Albert Cheung

All Publications

• Strain estimation in aortic roots from 4D echocardiographic images using medial modeling and deformable registration. Medical image analysis Aggarwal, A., Mortensen, P., Hao, J., Kaczmarczyk, Ł., Cheung, A. T., Al Ghofaily, L., Gorman, R. C., Desai, N. D., Bavaria, J. E., Pouch, A. M. 2023; 87: 102804

  Abstract

  Even though the central role of mechanics in the cardiovascular system is widely recognized, estimating mechanical deformation and strains in-vivo remains an ongoing practical challenge. Herein, we present a semi-automated framework to estimate strains from four-dimensional (4D) echocardiographic images and apply it to the aortic roots of patients with normal trileaflet aortic valves (TAV) and congenital bicuspid aortic valves (BAV). The method is based on fully nonlinear shell-based kinematics, which divides the strains into in-plane (shear and dilatational) and out-of-plane components. The results indicate that, even for size-matched non-aneurysmal aortic roots, BAV patients experience larger regional shear strains in their aortic roots. This elevated strains might be a contributing factor to the higher risk of aneurysm development in BAV patients. The proposed framework is openly available and applicable to any tubular structures.

  View details for DOI 10.1016/j.media.2023.102804

  View details for PubMedID 37060701

• Evaluation of the efficacy and safety of a novel dermatotomy device for central venous cannulation Keeyapaj, W., Cheung, A. T. LIPPINCOTT WILLIAMS & WILKINS. 2021: 994

  View details for Web of Science ID 000752526600429

• THE ECONOMIC CONSEQUENCES OF CARDIAC SURGERY ASSOCIATED ACUTE RENAL DYSFUNCTION AFTER HEART SURGERY. Seminars in thoracic and cardiovascular surgery DeAnda, A. J., Basu, R., Cheung, A. T., Shaw, A. 2020

  Abstract

  The STS definition of acute renal failure requires a three-fold rise in creatinine (CR), CR > 4 mg/dL (with at least 0.5mg/dL rise from pre-operative value), or new hemodialysis requirement. This definition does not capture the incidence, clinical impact, and economic burden of lesser degrees of acute renal dysfunction. A retrospective cohort study using discharge data from 650 hospitals was extracted from the Premier administrative database (2010-2014) for index cardiac cases (isolated CABG, isolated valve, and CABG-valve). We documented acute renal dysfunction through ICD 9-CM codes and hospital charges, excluding those patients with pre-existing renal dysfunction. The incidence, length of stay (LOS), and total hospital costs associated with renal dysfunction for each of the index procedures were captured. The results reported are unadjusted for demographic and clinical factors. 200,471procedures were available for analysis in the database. The mean age was 66 years, 68.2% were male and 74% were white. Based on ICD 9-CM codes and hospital charges for these cases, 27,216 (13.6%) patients had some level of renal dysfunction. In addition to increase in LOS, patients who developed renal dysfunction had an associated 57-85% increase in total cost of hospitalization. The incidence of renal dysfunction in this study is higher than reported previously. The STS definition of renal failure captures only severe disease and may miss lesser degrees of dysfunction, which nonetheless have an impact on patient outcome and costs.

  View details for DOI 10.1053/j.semtcvs.2020.11.014

  View details for PubMedID 33186738

• Three-Dimensional Transesophageal Echocardiography: Do We Have the Technology to Predict Outcomes in Ischemic Mitral Regurgitation? Journal of cardiothoracic and vascular anesthesia Shapeton, A. D., Cheung, A. T. 2020

  View details for DOI 10.1053/j.jvca.2020.04.036

  View details for PubMedID 32434721

• Sphenopalatine Ganglion Blockade for the Management of Postdural Puncture Headache After Lumbar Drain Placement in Patients Undergoing Thoracoabdominal Aortic Aneurysm Repair. Journal of cardiothoracic and vascular anesthesia Hickerson, L. C., Madden, A., Keeyapaj, W., Cheung, A. T. 2020

  View details for DOI 10.1053/j.jvca.2020.03.012

  View details for PubMedID 32553645

• Dynamic volumetric assessment of the aortic root: The influence of bicuspid aortic valve competence. The Annals of thoracic surgery Pouch, A. M., Patel, P. A., Desai, N. D., Yushkevich, N. n., Goodwin, M. n., Lai, E. K., Cheung, A. T., Moeller, P. n., Weiss, S. J., Gorman, J. H., Bavaria, J. E., Gorman, R. C. 2020

  Abstract

  Aortic root evaluation is conventionally based on two-dimensional measurements at a single phase of the cardiac cycle. This work presents an image analysis method for assessing dynamic three-dimensional changes in the aortic root of minimally calcified bicuspid aortic valves (BAVs) with and without moderate to severe aortic regurgitation.The aortic root was segmented over the full cardiac cycle in three-dimensional transesophageal echocardiographic images acquired from 19 patients with minimally calcified BAVs and from 16 patients with physiologically normal tricuspid aortic valves (TAVs). The size and dynamics of the aortic root were assessed using the following image-derived measurements: absolute mean root volume and mean area at the level of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction, as well as normalized root volume change and normalized area change of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction over the cardiac cycle.Normalized volume change over the cardiac cycle was significantly greater in BAV roots with moderate to severe regurgitation than in normal TAV roots and in BAV roots with no or mild regurgitation. Aortic root dynamics were most significantly different at the mid-level of the sinuses of Valsalva in BAVs with moderate to severe regurgitation than in competent TAVs and BAVs.Echocardiographic reconstruction of the aortic root demonstrates significant differences in dynamics of BAV roots with moderate to severe regurgitation relative to physiologically normal TAVs and competent BAVs. This finding may have implications for risk of future dilatation, dissection, or rupture, which warrant further investigation.

  View details for DOI 10.1016/j.athoracsur.2020.07.036

  View details for PubMedID 32987018

• Enhanced Recovery After Cardiac Surgery (ERAS Cardiac) Recommendations: An Important First Step-But There Is Much Work to Be Done. Journal of cardiothoracic and vascular anesthesia Gregory, A. J., Grant, M. C., Manning, M. W., Cheung, A. T., Ender, J., Sander, M., Zarbock, A., Stoppe, C., Meineri, M., Grocott, H. P., Ghadimi, K., Gutsche, J. T., Patel, P. A., Denault, A., Shaw, A., Fletcher, N., Levy, J. H. 2019

  View details for DOI 10.1053/j.jvca.2019.09.002

  View details for PubMedID 31570245

• The "Ice Age" in Cardiac Surgery: Evolution of the "Siberian" Method of Brain Protection During Deep Hypothermic Perfusionless Circulatory Arrest. Journal of cardiothoracic and vascular anesthesia Guvakov, D., Bezinover, D., Lomivorotov, V. V., Postnov, V. G., Weiss, S. J., Cheung, A. T., Swain, J., Lomivorotov, V. N. 2019

  Abstract

  Deep hypothermic perfusionless circulatory arrest was the first practical neuroprotective technique used for open-heart surgery. It was refined at the Novosibirsk Medical Research Center in Siberia and was actively used from the mid-1950s until 2001.This review describes the development of this technique and its contribution to our understanding of the dynamic changes in human physiology during induced hypothermia for circulatory arrest without extracorporeal perfusion. Deep hypothermic perfusionless circulatory arrest was an important stepping stone in the development of modern approaches in neuroprotection and monitoring during cardiac surgery.

  View details for DOI 10.1053/j.jvca.2019.04.001

  View details for PubMedID 31129071

• The Penn Classification Predicts Hospital Mortality in Acute Stanford Type A and Type B Aortic Dissections. Journal of cardiothoracic and vascular anesthesia Tien, M. n., Ku, A. n., Martinez-Acero, N. n., Zvara, J. n., Sun, E. C., Cheung, A. T. 2019

  Abstract

  Mortality in acute aortic dissection varies depending on anatomic location, extent, and associated complications. The Stanford classification guides surgical versus medical management. The Penn classification stratifies mortality risk in patients with Stanford type A aortic dissections undergoing surgery. The objective of the present study was to determine whether the Penn classification can predict hospital mortality in patients with acute Stanford type A and type B aortic dissections undergoing surgical or medical management.Retrospective, observational study.Tertiary care, university hospital.Patients with acute aortic dissection between January 2008 and December 2017.Examination of hospital mortality after surgical or medical management.Three hundred fifty-two patients had confirmed dissections (186 type A, 166 type B). The overall mortality was 18.8% for type A and 13.3% for type B. Penn class A patients with type A or type B dissections undergoing surgical repair had the lowest mortality (both 3.1%). Penn class B, C, or B+C patients with type A dissections and Penn class B+C patients with type B dissections undergoing medical management had the greatest incidence of mortality (50.0%-57.1%). All others had intermediate mortality (6.7%-39.3%). Logistic regression analysis demonstrated that Penn class B, C, and B+C patients had a greater odds of mortality and predicted mortality than did Penn class A patients.The Penn classification predicts hospital mortality in patients with acute Stanford type A or type B aortic dissections undergoing surgical or medical management. Early endovascular repair may confer lower risk of mortality in patients with type B dissections presenting without ischemia.

  View details for DOI 10.1053/j.jvca.2019.08.036

  View details for PubMedID 31558394

• Inhaled Nitric Oxide (iNO) and Inhaled Epoprostenol (iPGI(2)) Use in Cardiothoracic Surgical Patients: Is there Sufficient Evidence for Evidence-Based Recommendations? JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Rao, V., Ghadimi, K., Keeyapaj, W., Parsons, C. A., Cheung, A. T. 2018; 32 (3): 1452–57

  View details for PubMedID 29336971

• Preventing Brain Injury After Cardiopulmonary Bypass Will Require More Than Just Dialing Up the Pressure CIRCULATION Cheung, A. T., Messe, S. R. 2018; 137 (17): 1781–83

  View details for PubMedID 29685929

• Assessment of Left Ventricular Dimensions by Transoesophageal Echocardiography in Patients During Coronary Artery Bypass Surgery. Turkish journal of anaesthesiology and reanimation Bolliger, D., Poltera, C., Cheung, A. T., Couture, P., Michaux, I., Poelaert, J., Preisman, S., Skarvan, K., Buse, G. L., Seeberger, M. D. 2017; 45 (6): 367-373

  Abstract

  Normative values of left ventricular (LV) end-diastolic area and diameter (EDA and EDD) for intraoperative transoesophageal echocardiography (TEE) have not been established. We aimed to define the ranges of LV EDA and EDD for intraoperative TEE examinations in patients undergoing coronary artery bypass graft (CABG) surgery.A MEDLINE search for studies reporting LV EDA and EDD in CABG patients was performed. Individual-level dataset from 333 anaesthetised and mechanically ventilated patients with preserved LV function (study population) were received from 8 studies. EDA and calculated EDD values in the study population were compared with summary mean EDD values obtained by transthoracic echocardiography (TTE) in 2 studies of 500 awake patients with coronary artery disease (CAD). Further, the influence of prespecified factors on EDD was evaluated through a multivariate regression model.LV EDA and EDD values measured by TEE in anaesthetised CABG patients were 16.7±4.7 cm2 and 4.6±0.6 cm, respectively. EDD values measured by TEE in anaesthetised patients were 10% to 13% less those measured by TTE in 2 studies of awake patients (p<0.001). Body surface area, age and fractional area change but not sex were factors that affected LV EDD.LV EDD values measured by intraoperative TEE in anaesthetised and mechanically ventilated CABG patients were 10% to 13% less than those measured by TTE in awake CAD patients. This finding indicates that independent normative values specific for intraoperative TEE should be established for guiding intraoperative clinical decisions.

  View details for DOI 10.5152/TJAR.2017.25483

  View details for PubMedID 29359077

  View details for PubMedCentralID PMC5772417

• Spatiotemporal Segmentation and Modeling of the Mitral Valve in Real-Time 3D Echocardiographic Images. Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention Pouch, A. M., Aly, A. H., Lai, E. K., Yushkevich, N., Stoffers, R. H., Gorman, J. H., Cheung, A. T., Gorman, J. H., Gorman, R. C., Yushkevich, P. A. 2017; 10433: 746–54

  Abstract

  Transesophageal echocardiography is the primary imaging modality for preoperative assessment of mitral valves with ischemic mitral regurgitation (IMR). While there are well known echocardiographic insights into the 3D morphology of mitral valves with IMR, such as annular dilation and leaflet tethering, less is understood about how quantification of valve dynamics can inform surgical treatment of IMR or predict short-term recurrence of the disease. As a step towards filling this knowledge gap, we present a novel framework for 4D segmentation and geometric modeling of the mitral valve in real-time 3D echocardiography (rt-3DE). The framework integrates multi-atlas label fusion and template-based medial modeling to generate quantitatively descriptive models of valve dynamics. The novelty of this work is that temporal consistency in the rt-3DE segmentations is enforced during both the segmentation and modeling stages with the use of groupwise label fusion and Kalman filtering. The algorithm is evaluated on rt-3DE data series from 10 patients: five with normal mitral valve morphology and five with severe IMR. In these 10 data series that total 207 individual 3DE images, each 3DE segmentation is validated against manual tracing and temporal consistency between segmentations is demonstrated. The ultimate goal is to generate accurate and consistent representations of valve dynamics that can both visually and quantitatively provide insight into normal and pathological valve function.

  View details for PubMedID 29285527

• The value of preoperative 3-dimensional over 2-dimensional valve analysis in predicting recurrent ischemic mitral regurgitation after mitral annuloplasty. journal of thoracic and cardiovascular surgery Wijdh-den Hamer, I. J., Bouma, W., Lai, E. K., Levack, M. M., Shang, E. K., Pouch, A. M., Eperjesi, T. J., Plappert, T. J., Yushkevich, P. A., Hung, J., Mariani, M. A., Khabbaz, K. R., Gleason, T. G., Mahmood, F., Acker, M. A., Woo, Y. J., Cheung, A. T., Gillespie, M. J., Jackson, B. M., Gorman, J. H., Gorman, R. C. 2016; 152 (3): 847-859

  Abstract

  Repair for ischemic mitral regurgitation with undersized annuloplasty is characterized by high recurrence rates. We sought to determine the value of pre-repair 3-dimensional echocardiography over 2-dimensional echocardiography in predicting recurrence at 6 months.Intraoperative transesophageal 2-dimensional echocardiography and 3-dimensional echocardiography were performed in 50 patients undergoing undersized annuloplasty for ischemic mitral regurgitation. Two-dimensional echocardiography annular diameter and tethering parameters were measured in the apical 2- and 4-chamber views. A customized protocol was used to assess 3-dimensional annular geometry and regional leaflet tethering. Recurrence (grade ≥2) was assessed with 2-dimensional transthoracic echocardiography at 6 months.Preoperative 2- and 3-dimensional annular geometry were similar in all patients with ischemic mitral regurgitation. Preoperative 2- and 3-dimensional leaflet tethering were significantly higher in patients with recurrence (n = 13) when compared with patients without recurrence (n = 37). Multivariate logistic regression revealed preoperative 2-dimensional echocardiography posterior tethering angle as an independent predictor of recurrence with an optimal cutoff value of 32.0° (area under the curve, 0.81; 95% confidence interval, 0.68-0.95; P = .002) and preoperative 3-dimensional echocardiography P3 tethering angle as an independent predictor of recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84-1.00; P < .001). The predictive value of the 3-dimensional geometric multivariate model can be augmented by adding basal aneurysm/dyskinesis (area under the curve, 0.94; 95% confidence interval, 0.87-1.00; P < .001).Preoperative 3-dimensional echocardiography P3 tethering angle is a stronger predictor of ischemic mitral regurgitation recurrence after annuloplasty than preoperative 2-dimensional echocardiography posterior tethering angle, which is highly influenced by viewing plane. In patients with a preoperative P3 tethering angle of 29.9° or larger (especially when combined with basal aneurysm/dyskinesis), chordal-sparing valve replacement should be strongly considered.

  View details for DOI 10.1016/j.jtcvs.2016.06.040

  View details for PubMedID 27530639

• Modeling the Myxomatous Mitral Valve With Three-Dimensional Echocardiography. Annals of thoracic surgery Pouch, A. M., Jackson, B. M., Lai, E., Takebe, M., Tian, S., Cheung, A. T., Woo, Y. J., Patel, P. A., Wang, H., Yushkevich, P. A., Gorman, R. C., Gorman, J. H. 2016; 102 (3): 703-710

  Abstract

  Degenerative mitral valve disease is associated with variable and complex defects in valve morphology. Three-dimensional echocardiography (3DE) has shown promise in aiding preoperative planning for patients with this disease but to date has not been as transformative as initially predicted. The clinical usefulness of 3DE has been limited by the laborious methods currently required to extract quantitative data from the images.To maximize the utility of 3DE for preoperative valve evaluation, this work describes an automated 3DE image analysis method for generating models of the mitral valve that are well suited for both qualitative and quantitative assessment. The method is unique in that it captures detailed alterations in mitral leaflet and annular morphology and produces image-derived models with locally varying leaflet thickness. The method is evaluated on midsystolic transesophageal 3DE images acquired from 22 subjects with myxomatous degeneration and from 22 subjects with normal mitral valve morphology.Relative to manual image analysis, the automated method accurately represents both normal and complex leaflet geometries with a mean boundary displacement error on the order of one image voxel. A detailed quantitative analysis of the valves is presented and reveals statistically significant differences between normal and myxomatous valves with respect to numerous aspects of annular and leaflet geometry.This work demonstrates a successful methodology for the relatively rapid quantitative description of the complex mitral valve distortions associated with myxomatous degeneration. The methodology has the potential to significantly improve surgical planning for patients with complex mitral valve disease.

  View details for DOI 10.1016/j.athoracsur.2016.05.087

  View details for PubMedID 27492671

• Protocol for prevention of spinal cord ischemia after thoracoabdominal aortic surgery. Vascular Hobbs, R. D., Ullery, B. W., Mentzer, A. R., Cheung, A. T. 2016; 24 (4): 430-434

  Abstract

  This manuscript was written to present a systemic protocol for the prevention, early detection, and treatment of spinal cord ischemia following open and endovascular thoracoabdominal aortic operations.This protocol was a collaborative effort between surgeons, anesthesiologists and intensivists. It was implemented at our institution in November 2007. Nurses are trained to prevent, rapidly detect and ultimately aid in the treatment of spinal cord ischemia.Implementation of this protocol has aided in prevention, detection and treatment of spinal cord ischemia in patients after open and endovascular thoracoabdominal aortic operations.Standardized care and reliance on trained nursing staff to monitor for symptoms following thoracoabdominal aortic operations are safe and aid in the rapid detection, treatment and reversal of spinal cord ischemia.

  View details for DOI 10.1177/1708538115593193

  View details for PubMedID 26113574

• Sodium bicarbonate use and the risk of hypernatremia in thoracic aortic surgical patients with metabolic acidosis following deep hypothermic circulatory arrest. Annals of cardiac anaesthesia Ghadimi, K., Gutsche, J. T., Ramakrishna, H., Setegne, S. L., Jackson, K. R., Augoustides, J. G., Ochroch, E. A., Weiss, S. J., Bavaria, J. E., Cheung, A. T. 2016; 19 (3): 454-462

  Abstract

  Metabolic acidosis after deep hypothermic circulatory arrest (DHCA) for thoracic aortic operations is commonly managed with sodium bicarbonate (NaHCO 3 ). The purpose of this study was to determine the relationships between total NaHCO 3 dose and the severity of metabolic acidosis, duration of mechanical ventilation, duration of vasoactive infusions, and Intensive Care Unit (ICU) or hospital length of stay (LOS).In a single center, retrospective study, 87 consecutive elective thoracic aortic operations utilizing DHCA, were studied. Linear regression analysis was used to test for the relationships between the total NaHCO 3 dose administered through postoperative day 2, clinical variables, arterial blood gas values, and short-term clinical outcomes.Seventy-five patients (86%) received NaHCO 3 . Total NaHCO 3 dose averaged 136 ± 112 mEq (range: 0.0-535 mEq) per patient. Total NaHCO 3 dose correlated with minimum pH (r = 0.41, P < 0.0001), minimum serum bicarbonate (r = -0.40, P < 0.001), maximum serum lactate (r = 0.46, P = 0.007), duration of metabolic acidosis (r = 0.33, P = 0.002), and maximum serum sodium concentrations (r = 0.29, P = 0.007). Postoperative hypernatremia was present in 67% of patients and peaked at 12 h following DHCA. Eight percent of patients had a serum sodium ≥ 150 mEq/L. Total NaHCO 3 dose did not correlate with anion gap, serum chloride, not the duration of mechanical ventilator support, vasoactive infusions, ICU or hospital LOS.Routine administration of NaHCO 3 was common for the management of metabolic acidosis after DHCA. Total dose of NaHCO 3 was a function of the severity and duration of metabolic acidosis. NaHCO 3 administration contributed to postoperative hypernatremia that was often severe. The total NaHCO 3 dose administered was unrelated to short-term clinical outcomes.

  View details for DOI 10.4103/0971-9784.185527

  View details for PubMedID 27397449

  View details for PubMedCentralID PMC4971973

• Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation After Mitral Annuloplasty ANNALS OF THORACIC SURGERY Bouma, W., Lai, E. K., Levack, M. M., Shang, E. K., Pouch, A. M., Eperjesi, T. J., Plappert, T. J., Yushkevich, P. A., Mariani, M. A., Khabbaz, K. R., Gleason, T. G., Mahmood, F., Acker, M. A., Woo, Y. J., Cheung, A. T., Jackson, B. M., Gorman, J. H., Gorman, R. C. 2016; 101 (2): 567-575

  Abstract

  Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if prerepair three-dimensional (3D) echocardiography combined with a novel valve-modeling algorithm would be predictive of IMR recurrence 6 months after repair.Intraoperative transesophageal real-time 3D echocardiography was performed in 50 patients undergoing undersized ring annuloplasty for IMR and in 21 patients with normal mitral valves. A customized image analysis protocol was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥ grade 2) was assessed with two-dimensional transthoracic echocardiography 6 months after repair.Preoperative annular geometry was similar in all IMR patients, and preoperative leaflet tethering was significantly higher in patients with recurrent IMR (n=13) than in patients in whom IMR did not recur (n=37) (tethering index: 3.91 ± 1.01 vs 2.90 ± 1.17, p = 0.008; tethering angles of A3: 23.5° ± 8.9° vs 14.4° ± 11.4°, p = 0.012; P2: 44.4° ± 8.8° vs 28.2° ± 17.0°, p = 0.002; and P3: 35.2° ± 6.0° vs. 18.6° ± 12.7°, p < 0.001). Multivariate logistic regression analysis revealed the preoperative P3 tethering angle as an independent predictor of IMR recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84 to 1.00; p < 0.001).3D echocardiography combined with valve modeling is predictive of recurrent IMR. Preoperative regional leaflet tethering of segment P3 is a strong independent predictor of IMR recurrence after undersized ring annuloplasty. In patients with a preoperative P3 tethering angle of 29.9° or larger, chordal-sparing valve replacement rather than valve repair should be strongly considered.

  View details for DOI 10.1016/j.athoracsur.2015.09.076

  View details for Web of Science ID 000368189700039

  View details for PubMedCentralID PMC4718840

• Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation After Mitral Annuloplasty. The Annals of thoracic surgery Bouma, W., Lai, E. K., Levack, M. M., Shang, E. K., Pouch, A. M., Eperjesi, T. J., Plappert, T. J., Yushkevich, P. A., Mariani, M. A., Khabbaz, K. R., Gleason, T. G., Mahmood, F., Acker, M. A., Woo, Y. J., Cheung, A. T., Jackson, B. M., Gorman, J. H., Gorman, R. C. 2016; 101 (2): 567-75; discussion 575

  Abstract

  Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if prerepair three-dimensional (3D) echocardiography combined with a novel valve-modeling algorithm would be predictive of IMR recurrence 6 months after repair.Intraoperative transesophageal real-time 3D echocardiography was performed in 50 patients undergoing undersized ring annuloplasty for IMR and in 21 patients with normal mitral valves. A customized image analysis protocol was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥ grade 2) was assessed with two-dimensional transthoracic echocardiography 6 months after repair.Preoperative annular geometry was similar in all IMR patients, and preoperative leaflet tethering was significantly higher in patients with recurrent IMR (n=13) than in patients in whom IMR did not recur (n=37) (tethering index: 3.91 ± 1.01 vs 2.90 ± 1.17, p = 0.008; tethering angles of A3: 23.5° ± 8.9° vs 14.4° ± 11.4°, p = 0.012; P2: 44.4° ± 8.8° vs 28.2° ± 17.0°, p = 0.002; and P3: 35.2° ± 6.0° vs. 18.6° ± 12.7°, p < 0.001). Multivariate logistic regression analysis revealed the preoperative P3 tethering angle as an independent predictor of IMR recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84 to 1.00; p < 0.001).3D echocardiography combined with valve modeling is predictive of recurrent IMR. Preoperative regional leaflet tethering of segment P3 is a strong independent predictor of IMR recurrence after undersized ring annuloplasty. In patients with a preoperative P3 tethering angle of 29.9° or larger, chordal-sparing valve replacement rather than valve repair should be strongly considered.

  View details for DOI 10.1016/j.athoracsur.2015.09.076

  View details for PubMedID 26688087

  View details for PubMedCentralID PMC4718840

• Medially constrained deformable modeling for segmentation of branching medial structures: Application to aortic valve segmentation and morphometry MEDICAL IMAGE ANALYSIS Pouch, A. M., Tian, S., Takebe, M., Yuan, J., Gorman, R., Cheung, A. T., Wang, H., Jackson, B. M., Gorman, J. H., Gorman, R. C., Yushkevich, P. A. 2015; 26 (1): 217-231

  View details for DOI 10.1016/j.media.2015.09.003

  View details for Web of Science ID 000367490800018

• Medially constrained deformable modeling for segmentation of branching medial structures: Application to aortic valve segmentation and morphometry. Medical image analysis Pouch, A. M., Tian, S., Takebe, M., Yuan, J., Gorman, R., Cheung, A. T., Wang, H., Jackson, B. M., Gorman, J. H., Gorman, R. C., Yushkevich, P. A. 2015; 26 (1): 217-31

  Abstract

  Deformable modeling with medial axis representation is a useful means of segmenting and parametrically describing the shape of anatomical structures in medical images. Continuous medial representation (cm-rep) is a "skeleton-first" approach to deformable medial modeling that explicitly parameterizes an object's medial axis and derives the object's boundary algorithmically. Although cm-rep has effectively been used to segment and model a number of anatomical structures with non-branching medial topologies, the framework is challenging to apply to objects with branching medial geometries since branch curves in the medial axis are difficult to parameterize. In this work, we demonstrate the first clinical application of a new "boundary-first" deformable medial modeling paradigm, wherein an object's boundary is explicitly described and constraints are imposed on boundary geometry to preserve the branching configuration of the medial axis during model deformation. This "boundary-first" framework is leveraged to segment and morphologically analyze the aortic valve apparatus in 3D echocardiographic images. Relative to manual tracing, segmentation with deformable medial modeling achieves a mean boundary error of 0.41 ± 0.10 mm (approximately one voxel) in 22 3DE images of normal aortic valves at systole. Deformable medial modeling is additionally demonstrated on pathological cases, including aortic stenosis, Marfan syndrome, and bicuspid aortic valve disease. This study demonstrates a promising approach for quantitative 3DE analysis of aortic valve morphology.

  View details for DOI 10.1016/j.media.2015.09.003

  View details for PubMedID 26462232

  View details for PubMedCentralID PMC4679439

• Severity and Duration of Metabolic Acidosis After Deep Hypothermic Circulatory Arrest for Thoracic Aortic Surgery JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Ghadimi, K., Gutsche, J. T., Setegne, S. L., Jackson, K. R., Augoustides, J. G., Ochroch, E. A., Bavaria, J. E., Cheung, A. T. 2015; 29 (6): 1432-1440

  Abstract

  To determine the severity, duration, and contributing factors for metabolic acidosis after deep hypothermic circulatory arrest (DHCA).Retrospective observational study.University hospital.Eighty-seven consecutive patients undergoing elective thoracic aortic surgery with DHCA.Regression analysis was used to test for relationships between the severity of metabolic acidosis and clinical and laboratory variables.Minimum pH averaged 7.27±0.06, with 76 (87%) having a pH<7.35; 55 (63%), a pH<7.30; and 7 (8%), a pH<7.20. The mean duration of metabolic acidosis was 7.9±5.0 hours (range: 0.0 - 26.8), and time to minimum pH after DHCA was 4.3±2.0 hours (1.0 - 10.0 hours). Hyperchloremia contributed to metabolic acidosis in 89% of patients. The severity of metabolic acidosis correlated with maximum lactate (p<0.0001) and hospital length of stay (LOS) (r = 0.22, p<0.05), but not with DHCA time, DHCA temperature, duration of vasoactive infusions, or ICU LOS. Patient BMI was the sole preoperative predictor of the severity of postoperative metabolic acidosis.This retrospective analysis involved short-term clinical outcomes related to pH severity and duration, which indirectly may have included the impact of sodium bicarbonate administration.Metabolic acidosis was common and severe after DHCA and was attributed to both lactic and hyperchloremic acidosis. DHCA duration and temperature had little impact on the severity of metabolic acidosis. The severity of metabolic acidosis was best predicted by the BMI and had minimal effects on short-term outcomes. Preventing hyperchloremic acidosis has the potential to decrease the severity of metabolic acidosis after DHCA.

  View details for DOI 10.1053/j.jvca.2015.07.025

  View details for Web of Science ID 000367421800006

  View details for PubMedID 26706792

• Pro: Patients at Risk for Spinal Cord Ischemia After Thoracic Endovascular Aortic Repairs Should Receive Prophylactic Cerebrospinal Fluid Drainage. Journal of cardiothoracic and vascular anesthesia Arora, H., Ullery, B. W., Kumar, P. A., Cheung, A. T. 2015; 29 (5): 1376-1380

  View details for DOI 10.1053/j.jvca.2015.05.192

  View details for PubMedID 26384635

• Reversible spinal cord ischemia as a complication of acute aortic intramural hematoma VASCULAR Ullery, B. W., Hobbs, R. D., Cheung, A. T. 2015; 23 (4): 427-431

  Abstract

  Aortic intramural hematoma is a variant of acute aortic dissection characterized by localized hemorrhage into the aortic media causing a separation of the intimal and adventitial layers of the aorta. Malperfusion represents an unusual presenting sign of acute intramural hematoma. Herein, we describe the case of a patient with an acute Type A IMH who developed reversible ischemic spinal cord syndrome after presenting with paraplegia as a consequence of malperfusion. A decision was made to delay operative repair and, instead, emergently apply medical interventions to increase spinal cord perfusion pressure. Medical treatment was effective for the treatment of spinal cord ischemia and operative repair of the intramural hematoma was accomplished after complete recovery of neurologic function. This is the third case ever reported of an intramural hematoma presenting in the form of spinal cord ischemia.

  View details for DOI 10.1177/1708538114549067

  View details for Web of Science ID 000357518700014

  View details for PubMedID 25193357

• Pseudo-tamponade during transvenous lead extraction. Heart rhythm Sadek, M. M., Epstein, A. E., Cheung, A. T., Schaller, R. D. 2015; 12 (4): 849-50

  View details for DOI 10.1016/j.hrthm.2014.12.016

  View details for PubMedID 25533583

• Segmentation of the Aortic Valve Apparatus in 3D Echocardiographic Images: Deformable Modeling of a Branching Medial Structure Pouch, A. M., Tian, S., Takabe, M., Wang, H., Yuan, J., Cheung, A. T., Jackson, B. M., Gorman, J. H., Gorman, R. C., Yushkevich, P. A., Camara, O., Mansi, T., Pop, M., Rhode, K., Sermesant, M., Young, A. SPRINGER-VERLAG BERLIN. 2015: 196–203

  Abstract

  3D echocardiographic (3DE) imaging is a useful tool for assessing the complex geometry of the aortic valve apparatus. Segmentation of this structure in 3DE images is a challenging task that benefits from shape-guided deformable modeling methods, which enable inter-subject statistical shape comparison. Prior work demonstrates the efficacy of using continuous medial representation (cm-rep) as a shape descriptor for valve leaflets. However, its application to the entire aortic valve apparatus is limited since the structure has a branching medial geometry that cannot be explicitly parameterized in the original cm-rep framework. In this work, we show that the aortic valve apparatus can be accurately segmented using a new branching medial modeling paradigm. The segmentation method achieves a mean boundary displacement of 0.6 ± 0.1 mm (approximately one voxel) relative to manual segmentation on 11 3DE images of normal open aortic valves. This study demonstrates a promising approach for quantitative 3DE analysis of aortic valve morphology.

  View details for PubMedID 26247062

  View details for PubMedCentralID PMC4523230

• Invited commentary. The Annals of thoracic surgery Gutsche, J. T., Cheung, A. T. 2014; 97 (6): 1944-5

  View details for DOI 10.1016/j.athoracsur.2014.02.048

  View details for PubMedID 24882282

• The rationale and development of an adult cardiac anesthesia module to supplement the society of thoracic surgeons national database: using data to drive quality. Anesthesia and analgesia Aronson, S., Mathew, J. P., Cheung, A. T., Shore-Lesserson, L., Troianos, C. A., Reeves, S. 2014; 118 (5): 925-32

  View details for DOI 10.1213/ANE.0000000000000184

  View details for PubMedID 24781564

• Invited commentary. The Annals of thoracic surgery Cheung, A. T., Kofke, W. A. 2014; 97 (4): 1225-6

  View details for DOI 10.1016/j.athoracsur.2013.11.010

  View details for PubMedID 24694407

• Feasibility of in vivo human aortic valve modeling using real-time three-dimensional echocardiography. The Annals of thoracic surgery Jassar, A. S., Levack, M. M., Solorzano, R. D., Pouch, A. M., Ferrari, G., Cheung, A. T., Ferrari, V. A., Gorman, J. H., Gorman, R. C., Jackson, B. M. 2014; 97 (4): 1255-8

  Abstract

  Surgical techniques for aortic valve (AV) repair are directed toward restoring normal structural relationships in the aortic root and rely on detailed assessment of root and valve anatomy. Noninvasive three-dimensional (3D) imaging and modeling may assist in patient selection and operative planning.Transesophageal real-time 3D echocardiographic images of 5 patients with normal AVs were acquired. The aortic root and the annulus were manually segmented at end diastole using a 36-point rotational template. The AV leaflets and the coaptation zone were manually segmented in parallel 1-mm cross sections. Quantitative 3D models of the AV and root were generated and used to measure standard anatomic parameters and were compared to conventional two-dimensional echocardiographic measurements. All measurements are given as mean±SD.Annular, sinus, and sinotubular junction areas were 4.1±0.6 cm2, 7.5±1.2 cm2, and 3.9±1.0 cm2, respectively. Root diameters (measured in three locations) by 3D model inspection and two-dimensional echocardiography measurement correlated (R2=0.75). Noncoapted areas of the left, right, and noncoronary leaflets were 1.9±0.2 cm2, 1.6±0.3 cm2, and 1.6±0.3 cm2, respectively. Mean coaptation areas for the left-right, left-noncoronary, and right-noncoronary coaptation zones were 87.7±36.9 mm2, 69.9±20.7 mm2, and 114.2±23.0 mm2, respectively. The mean ratio of noncoapted leaflet area to annular area was 1.3±0.2.High-resolution 3D models of the in vivo normal human aortic root and valve were generated using 3D echocardiography. Quantitative 3D models and analysis may assist in characterization of pathology and decision making for AV repair.

  View details for DOI 10.1016/j.athoracsur.2013.12.017

  View details for PubMedID 24518577

  View details for PubMedCentralID PMC3975669

• Regional Annular Geometry in Patients With Mitral Regurgitation: Implications for Annuloplasty Ring Selection ANNALS OF THORACIC SURGERY Jassar, A. S., Vergnat, M., Jackson, B. M., McGarvey, J. R., Cheung, A. T., Ferrari, G., Woo, Y. J., Acker, M. A., Gorman, R. C., Gorman, J. H. 2014; 97 (1): 64-70

  Abstract

  The saddle shape of the normal mitral annulus has been quantitatively described by several groups. There is strong evidence that this shape is important to valve function. A more complete understanding of regional annular geometry in diseased valves may provide a more educated approach to annuloplasty ring selection and design. We hypothesized that mitral annular shape is markedly distorted in patients with diseased valves.Real-time 3-dimensional echocardiography was performed in 20 patients with normal mitral valves, 10 with ischemic mitral regurgitation, and 20 with myxomatous mitral regurgitation (MMR). Thirty-six annular points were defined to generate a 3-dimensional model of the annulus. Regional annular parameters were measured from these renderings. Left ventricular inner diameter was obtained from 2-dimensional echocardiographic images.Annular geometry was significantly different among the three groups. The annuli were larger in the MMR and in the ischemic mitral regurgitation groups. The annular enlargement was greater and more pervasive in the MMR group. Both diseases were associated with annular flattening, although though the regional distribution of that flattening was different between groups. Left ventricular inner diameter was increased in both groups. However, relative to the Left ventricular inner diameter, the annulus was disproportionately dilated in the MMR group.Patients with MMR and ischemic mitral regurgitation have enlarged and flattened annuli. In the case of MMR, annular distortions may be the driving factor leading to valve incompetence. These data suggest that the goal of annuloplasty should be the restoration of normal annular saddle shape and that the use of flexible, partial, and flat rings may be ill advised.

  View details for DOI 10.1016/j.athoracsur.2013.07.048

  View details for Web of Science ID 000329155900020

  View details for PubMedID 24070698

• Percutaneous closure of an aortic pseudoaneurysm due to saphenous vein graft dehiscence with an Amplatzer vascular plug. JACC. Cardiovascular interventions Shreenivas, S. S., Lilly, S., Desai, N. D., Farooki, A., Cheung, A. T., Acker, M. A., Herrmann, H. C., Anwaruddin, S. 2013; 6 (10): 1103-4

  View details for DOI 10.1016/j.jcin.2013.03.022

  View details for PubMedID 24156971

• Invited commentary. The Annals of thoracic surgery Ridley, C. H., Adler, J. V., Cheung, A. T. 2013; 96 (3): 1061

  View details for DOI 10.1016/j.athoracsur.2013.06.057

  View details for PubMedID 23992698

• A Pilot Study of Darbepoetin Alfa for Prophylactic Neuroprotection in Aortic Surgery NEUROCRITICAL CARE Messe, S. R., McGarvey, M. L., Bavaria, J. E., Pochettino, A., Szeto, W. Y., Cheung, A. T., Leitner, E., Miller, S. W., Kasner, S. E. 2013; 18 (1): 75-80

  Abstract

  Descending aortic (DA) surgery poses a high risk for spinal and cerebral infarction and routine use of lumbar drains allows for measurement of CSF markers of neurologic injury. Erythropoiesis medications have extensive preclinical data demonstrating neuroprotection. We hypothesized that prophylactic darbepoetin alfa (DARB) given before surgery reduces neurologic injury in patients undergoing DA repair.We performed a prospective adaptive dose-finding trial of prophylactic DARB ( www.clinicaltrials.gov NCT00647998) that terminated prematurely following publication of an erythropoietin stroke study showing possible harm. Enrollment halted before dose adjustments; nine patients each received 1 mg/kg IV DARB immediately before surgery. A prospective cohort of nine untreated patients was subsequently obtained for comparison. The primary outcome of death or neurologic impairment at discharge occurred in 1/9 (11 %) DARB patients and 3/9 (33 %) controls (p = 0.58). There were no statistical differences in changes of CSF biomarkers from baseline to 48 h comparing DARB patients to controls: S100β, median 214 versus 260 ng/ml (p = 0.69); glial fibrillary acidic protein (GFAP), median 0.022 versus 0.58 ng/ml (p = 0.45). In patients with early perioperative neurologic ischemia, there were greater changes in CSF biomarkers, compared to those without ischemia: S100β, median 2301 versus 124 ng/ml (p = 0.04); GFAP, median 31.78 versus 0.31 ng/ml (p = 0.34).There were no significant effects of prophylactic DARB on clinical outcome or CSF markers of neurologic injury in this pilot study, although all point estimates favored treatment. DA repair is a promising model of prophylactic neuroprotection.

  View details for DOI 10.1007/s12028-012-9710-4

  View details for Web of Science ID 000314708500013

  View details for PubMedID 22528284

• The effect of surgical and transcatheter aortic valve replacement on mitral annular anatomy. The Annals of thoracic surgery Vergnat, M., Levack, M. M., Jackson, B. M., Bavaria, J. E., Herrmann, H. C., Cheung, A. T., Weiss, S. J., Gorman, J. H., Gorman, R. C. 2013; 95 (2): 614-9

  Abstract

  The effect of aortic valve replacement on three-dimensional mitral annular geometry has not been well described. Emerging transcatheter approaches for aortic valve replacement employ fundamentally different mechanical techniques for achieving fixation and seal of the prosthetic valve than standard surgical aortic valve replacement. This study compares the immediate impact of transcatheter aortic valve replacement (TAVR) and standard surgical aortic valve replacement (AVR) on mitral annular anatomy.Real-time three-dimensional echocardiography was performed in patients undergoing TAVR using the Edwards Sapien valve (n = 10 [Edwards Lifesciences, Irvine, CA]) or AVR (n = 10) for severe aortic stenosis. Mitral annular geometric indexes were measured using Tomtec EchoView (Tomtec Imaging Systems, Munich, Germany) to assess regional and global annular geometry.Mixed between-within analysis of variance showed no differences between TAVR and AVR groups in any of the mitral annular geometric indices preoperatively. However, postoperative analysis did demonstrate an effect of AVR on geometry. Patients undergoing open AVR had significant decrease in annular height, septolateral diameter, mitral valve transverse diameter, and mitral annular area after valve replacement (p ≤ 0.006). Similar changes were not noted in the TAVR group.Mitral annular geometry is better preserved by TAVR than by AVR. Thus, TAVR may be a more physiologic approach to aortic replacement.

  View details for DOI 10.1016/j.athoracsur.2012.10.026

  View details for PubMedID 23245440

  View details for PubMedCentralID PMC3607374

• No increased risk of spinal cord ischemia in delayed AAA repair following thoracic aortic surgery. Vascular and endovascular surgery Ullery, B. W., Wang, G. J., Woo, E. Y., Cheung, A. T., McGarvey, M. L., Carpenter, J. P., Fairman, R. M., Jackson, B. M. 2013; 47 (2): 85-91

  Abstract

  To examine the results of open or endovascular abdominal aortic aneurysm (AAA) repair following prior open or endovascular thoracic aortic surgery.A retrospective review of all patients who underwent AAA repair in a delayed fashion following prior thoracic aortic surgery at a single university hospital between 1999 and 2011 was performed.Thirteen patients underwent AAA repair following prior thoracic aortic repair. Mean age was 68.9 ± 6.9 years and 77% (n = 10) were male. Three patients experienced transient delayed-onset spinal cord ischemia (SCI) following initial thoracic surgery. Mean time interval between initial thoracic aortic surgery and subsequent AAA repair was 2.0 ± 1.8 years. Overall rate of SCI and 30-day mortality after delayed AAA repair was 0%.This series does not demonstrate any evidence of increased risk of perioperative mortality or SCI in patients undergoing delayed AAA repair after prior thoracic aortic surgery.

  View details for DOI 10.1177/1538574412474500

  View details for PubMedID 23339150

• Vascular distribution of stroke and its relationship to perioperative mortality and neurologic outcome after thoracic endovascular aortic repair JOURNAL OF VASCULAR SURGERY Ullery, B. W., McGarvey, M., Cheung, A. T., Fairman, R. M., Jackson, B. M., Woo, E. Y., Desai, N. D., Wang, G. J. 2012; 56 (6): 1510-1517

  Abstract

  This study assessed the vascular distribution of stroke after thoracic endovascular aortic repair (TEVAR) and its relationship to perioperative death and neurologic outcome.A retrospective review was performed for patients undergoing TEVAR between 2001 and 2010. Aortic arch hybrid and abdominal debranching cases were excluded. Demographics, operative variables, and neurologic complications were examined. Stroke was defined as any new focal or global neurologic deficit lasting>24 hours with radiographic confirmation of acute intracranial pathology.Perioperative stroke occurred in 20 of 530 patients (3.8%) undergoing TEVAR. The cohort was 55% male and a mean age of 75.2±8.9 years (range, 57-90 years). Among patients with perioperative strokes, the indication for surgery was degenerative aneurysm in 14 (mean diameter, 6.8 cm), acute type B dissection in four, penetrating atherosclerotic aneurysm in one, and aortic transection in one. Cases were performed urgently or as an emergency in 60%. The proximal landing zone was zone 2 in 11 or zone 3 in nine. All strokes were embolic. The vascular distribution of stroke involved the anterior cerebral (AC) circulation in eight (zone 2, n=5) and the posterior cerebral (PC) circulation in 12 (zone 2, n=6). Laterality of cerebral infarction included five right-sided, eight left-sided, and seven bilateral strokes. Nine strokes were diagnosed<24 hours after operation. There was no difference in baseline demographics, aortic pathology, acuity, zone coverage, preoperative left subclavian artery revascularization, number of stents, or estimated blood loss between stroke groups based on vascular distribution. Independent risk factors for any perioperative stroke were chronic renal insufficiency (odds ratios [OR], 4.65; 95% confidence interval [CI], 1.22-17.7; P=.02) and history of prior stroke (OR, 4.92; 95% CI, 1.69-14.4; P=.004); the risk factor for AC stroke was prior stroke (OR, 7.67; 95% CI, 1.25-46.9; P=.03) and the risk factors for PC stroke were age (OR, 1.11; 95% CI, 1.00-1.23; P=.04), prior stroke (OR, 7.53; 95% CI, 1.78-31.8; P=.006), zone 2 coverage (OR, 6.11; 95% CI, 1.15-32.3; P=.03), and penetrating atherosclerotic ulcer (OR, 32.7; 95% CI, 1.33-807.2; P=.03). Overall in-hospital mortality was 20% (n=4), with those sustaining PC strokes observed to trend toward increased mortality (33% vs 0%; P=.12). Patients with AC strokes were more likely than those with PC strokes to achieve complete recovery of neurologic deficits before discharge (75% vs 17%; P=.02).Perioperative stroke after TEVAR is primarily an embolic event. Although infrequent, stroke was associated with significant morbidity and death, particularly among those with strokes involving the PC circulation.

  View details for DOI 10.1016/j.jvs.2012.05.086

  View details for Web of Science ID 000311489800004

  View details for PubMedID 22841287

• Annuloplasty ring dehiscence in ischemic mitral regurgitation. The Annals of thoracic surgery Levack, M. M., Vergnat, M., Cheung, A. T., Acker, M. A., Gorman, R. C., Gorman, J. H. 2012; 94 (6): 2132

  View details for DOI 10.1016/j.athoracsur.2012.04.051

  View details for PubMedID 23176936

  View details for PubMedCentralID PMC4062973

• Invited commentary. The Annals of thoracic surgery Gutsche, J. T., Cheung, A. T. 2012; 94 (1): 116

  View details for DOI 10.1016/j.athoracsur.2012.04.067

  View details for PubMedID 22734979

• Neurological complications of thoracic endovascular aortic repair. Seminars in cardiothoracic and vascular anesthesia Ullery, B. W., Wang, G. J., Low, D., Cheung, A. T. 2011; 15 (4): 123-140

  Abstract

  Thoracic endovascular aortic repair (TEVAR) has decreased the morbidity and mortality associated with open surgical repair of descending thoracic aortic diseases, but important complications unique to the procedure remain. Spinal cord ischemia and infarction is a recognized complication caused by endovascular coverage or injury to spinal cord collateral vessels. Stroke is a consequence of thromboembolism or coverage of aortic arch branch vessels with insufficient collateral circulation. Understanding the risk factors and the pathophysiology of neurological complications of TEVAR are important for the successful anesthetic and surgical management and treatment of patients undergoing endovascular procedures involving the thoracic aorta.

  View details for DOI 10.1177/1089253211424224

  View details for PubMedID 22025398

• Risk factors, outcomes, and clinical manifestations of spinal cord ischemia following thoracic endovascular aortic repair 39th Annual Symposium of the Society-for-Clinical-Vascular-Surgery Ullery, B. W., Cheung, A. T., Fairman, R. M., Jackson, B. M., Woo, E. Y., Bavaria, J., Pochettino, A., Wang, G. J. MOSBY-ELSEVIER. 2011: 677–84

  Abstract

  The purpose of this study was to assess the incidence, risk factors, and clinical manifestations of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR).A retrospective review of a prospectively collected database was performed for all patients undergoing TEVAR at a single academic institution between July 2002 and June 2010. Preoperative demographics, procedure-related variables, and clinical details related to SCI were examined. Logistic regression analysis was performed to identify risk factors for the development of SCI.Of the 424 patients who underwent TEVAR during the study period, 12 patients (2.8%) developed SCI. Mean age of this cohort with SCI was 69.6 years (range, 44-84 years), and 7 were women. One-half of these patients had prior open or endovascular aortic repair. Indication for surgery was either degenerative aneurysm (n = 8) or dissection (n = 4). Six TEVARs were performed electively, with the remaining done either urgently or emergently due to contained rupture (n = 2), dissection with malperfusion (n = 2), or severe back pain (n = 2). All 12 patients underwent extent C endovascular coverage. Multivariate regression analysis demonstrated chronic renal insufficiency to be independently associated with SCI (odds ratio [OR], 4.39; 95% confidence interval [CI], 1.2-16.6; P = .029). Onset of SCI occurred at a median of 10.6 hours (range, 0-229 hours) postprocedure and was delayed in 83% (n = 10) of patients. Clinical manifestations of SCI included lower extremity paraparesis in 9 patients and paraplegia in 3 patients. At SCI onset, average mean arterial pressure (MAP) and lumbar cerebrospinal fluid (CSF) pressure was 77 mm Hg and 10 mm Hg, respectively. Therapeutic interventions increased blood pressure to a significantly higher average MAP of 99 mm Hg (P = .001) and decreased lumbar CSF pressure to a mean of 7 mm Hg (P = .30) at the time of neurologic recovery. Thirty-day mortality was 8% (1 of 12 patients). The single patient who expired, never recovered any lower extremity neurologic function. All patients surviving to discharge experienced either complete (n = 9) or incomplete (n = 2) neurologic recovery. At mean follow-up of 49 months, 7 of 9 patients currently alive continued to exhibit complete, sustained neurologic recovery.Spinal cord ischemia after TEVAR is an uncommon, but important complication. Preoperative renal insufficiency was identified as a risk factor for the development of SCI. Early detection and treatment of SCI with blood pressure augmentation alone or in combination with CSF drainage was effective in most patients, with the majority achieving complete, long-term neurologic recovery.

  View details for DOI 10.1016/j.jvs.2011.03.259

  View details for Web of Science ID 000294505300010

  View details for PubMedID 21571494

• Saddle-shape annuloplasty increases mitral leaflet coaptation after repair for flail posterior leaflet. Annals of thoracic surgery Vergnat, M., Jackson, B. M., Cheung, A. T., Weiss, S. J., Ratcliffe, S. J., Gillespie, M. J., Woo, Y. J., Bavaria, J. E., Acker, M. A., Gorman, R. C., Gorman, J. H. 2011; 92 (3): 797-803

  Abstract

  The primary goal of surgical mitral repair is the reestablishment of normal leaflet coaptation. Surgical techniques that maintain or restore leaflet geometry promote leaflet coaptation. Recent 3-dimensional (3D) echocardiographic studies have shown that saddle-shaped annuloplasty has a salutary influence on leaflet geometry. Therefore we hypothesized that saddle-shaped annuloplasty would improve leaflet coaptation in cases of repair for flail posterior leaflet segments.Sixteen patients with flail posterior segment and severe mitral regurgitation had valve repair using standard techniques. Eight patients received saddle-shaped annuloplasty and 8 patients received flat annuloplasty. Real-time 3D transesophageal echocardiography was performed before and after repair. Images were analyzed using custom software to calculate mitral annular area (MAA), septolateral dimension (SLD), intercommissural width (CW), total leaflet area (TLA), and leaflet coaptation area (LCA).Postrepair MAA (flat, 588.6±26.5 mm2; saddle, 628.0±35.3 mm2; p=0.12) and TLA (flat, 2198.5±151.6 mm2; saddle, 2303.9±183.8 mm2; p=0.67) were similar in both groups. Postrepair LCA was significantly greater in the saddle group than in the flat group (226.8±24.0 mm2 and 154.0±13.0 mm2, respectively; p=0.02).Real-time 3D echocardiography and novel imaging software provide a powerful tool for analyzing mitral leaflet coaptation. When compared with flat annuloplasty, saddle-shaped annuloplasty improves LCA after mitral valve repair for severe mitral regurgitation secondary to flail posterior leaflet segment. Use of saddle-shaped annuloplasty devices may increase repair durability.

  View details for DOI 10.1016/j.athoracsur.2011.04.047

  View details for PubMedID 21803330

• Reversal of Delayed-Onset Paraparesis After Revision Thoracic Endovascular Aortic Repair For Ruptured Thoracic Aortic Aneurysm ANNALS OF VASCULAR SURGERY Ullery, B. W., Cheung, A. T., McGarvey, M. L., Jackson, B. M., Wang, G. J. 2011; 25 (6)

  Abstract

  Thoracic endovascular aortic repair (TEVAR) is an important surgical option for the emergency treatment of ruptured thoracic aortic aneurysms, but is associated with a risk of spinal cord ischemia (SCI). Although risk factors for the development of SCI have been well described, the effectiveness of treatment to increase spinal cord perfusion pressure remains incompletely understood. We report the successful treatment of delayed-onset paraparesis after revision TEVAR for acute descending thoracic aortic rupture with the combined use of blood pressure augmentation and cerebrospinal fluid drainage. The clinical manifestations, pathophysiology, and management of SCI after TEVAR are reviewed.

  View details for DOI 10.1016/j.avsg.2010.12.043

  View details for Web of Science ID 000293269500028

  View details for PubMedID 21621971

• Invited commentary. The Annals of thoracic surgery Falk, S. A., Cheung, A. T. 2011; 92 (2): 533-4

  View details for DOI 10.1016/j.athoracsur.2011.03.013

  View details for PubMedID 21801911

• Classification of acute type a dissection: focus on clinical presentation and extent EUROPEAN JOURNAL OF CARDIO-THORACIC SURGERY Augoustides, J. G., Szeto, W. Y., Desai, N. D., Pochettino, A., Cheung, A. T., Savino, J. S., Bavaria, J. E. 2011; 39 (4): 519-522

  Abstract

  Recent advances in the management of acute Stanford type A dissection have highlighted the clinical importance of clinical presentation and extent of dissection. The Penn classification of type A clinical presentations is based on ischemic profiles that not only determine mortality but also influence management options. The extent of type A dissection as summarized by the DeBakey classification significantly determines the role of endovascular intervention in this important disease. We propose an integration of these three classifications of acute type A dissection as a framework for future advances in diagnosis, intervention and prognosis.

  View details for DOI 10.1016/j.ejcts.2010.05.038

  View details for Web of Science ID 000289341100014

  View details for PubMedID 20615719

• Ischemic Mitral Regurgitation: A Quantitative Three-Dimensional Echocardiographic Analysis ANNALS OF THORACIC SURGERY Vergnat, M., Jassar, A. S., Jackson, B. M., Ryan, L. P., Eperjesi, T. J., Pouch, A. M., Weiss, S. J., Cheung, A. T., Acker, M. A., Gorman, J. H., Gorman, R. C. 2011; 91 (1): 157-164

  Abstract

  A comprehensive three-dimensional echocardiography based approach is applied to preoperative mitral valve (MV) analysis in patients with ischemic mitral regurgitation (IMR). This method is used to characterize the heterogeneous nature of the pathologic anatomy associated with IMR.Intraoperative real-time three-dimensional transesophageal echocardiograms of 18 patients with IMR (10 with anterior, 8 with inferior infarcts) and 17 patients with normal MV were analyzed. A customized image analysis protocol was used to assess global and regional determinants of annular size and shape, leaflet tethering and curvature, relative papillary muscle anatomy, and anatomic regurgitant orifice area.Both mitral annular area and MV tenting volume were increased in the IMR group as compared with patients with normal MV (mitral annular area=1,065±59 mm2 versus 779±44 mm2, p=0.001; and MV tenting volume=3,413±403 mm3 versus 1,696±200 mm3, p=0.001, respectively). Within the IMR group, patients with anterior infarct had larger annuli (1,168±99 mm2) and greater tenting volumes (4,260±779 mm3 versus 2,735±245 mm3, p=0.06) than the inferior infarct subgroup. Papillary-annular distance was increased in the IMR group relative to normal; these distances were largest in patients with anterior infarcts. Whereas patients with normal MV had very consistent anatomic determinants, annular shape and leaflet tenting distribution in the IMR group were exceedingly variable. Mean anatomic regurgitant orifice area was 25.8±3.0 mm2, and the number of discrete regurgitant orifices varied from 1 to 4.Application of custom analysis techniques to three-dimensional echocardiography images allows a quantitative and systematic analysis of the MV, and demonstrates the extreme variability in pathologic anatomy that occurs in patients with severe IMR.

  View details for DOI 10.1016/j.athoracsur.2010.09.078

  View details for Web of Science ID 000285411700030

  View details for PubMedID 21172506

  View details for PubMedCentralID PMC3021251

• Quantitative mitral valve modeling using real-time three-dimensional echocardiography: technique and repeatability. The Annals of thoracic surgery Jassar, A. S., Brinster, C. J., Vergnat, M., Robb, J. D., Eperjesi, T. J., Pouch, A. M., Cheung, A. T., Weiss, S. J., Acker, M. A., Gorman, J. H., Gorman, R. C., Jackson, B. M. 2011; 91 (1): 165-71

  Abstract

  Real-time three-dimensional (3D) echocardiography has the ability to construct quantitative models of the mitral valve (MV). Imaging and modeling algorithms rely on operator interpretation of raw images and may be subject to observer-dependent variability. We describe a comprehensive analysis technique to generate high-resolution 3D MV models and examine interoperator and intraoperator repeatability in humans.Patients with normal MVs were imaged using intraoperative transesophageal real-time 3D echocardiography. The annulus and leaflets were manually segmented using a TomTec Echo-View workstation. The resultant annular and leaflet point cloud was used to generate fully quantitative 3D MV models using custom Matlab algorithms. Eight images were subjected to analysis by two independent observers. Two sequential images were acquired for 6 patients and analyzed by the same observer. Each pair of annular tracings was compared with respect to conventional variables and by calculating the mean absolute distance between paired renderings. To compare leaflets, MV models were aligned so as to minimize their sum of squares difference, and their mean absolute difference was measured.Mean absolute annular and leaflet distance was 2.4±0.8 and 0.6±0.2 mm for the interobserver and 1.5±0.6 and 0.5±0.2 mm for the intraobserver comparisons, respectively. There was less than 10% variation in annular variables between comparisons.These techniques generate high-resolution, quantitative 3D models of the MV and can be used consistently to image the human MV with very small interoperator and intraoperator variability. These data lay the framework for reliable and comprehensive noninvasive modeling of the normal and diseased MV.

  View details for DOI 10.1016/j.athoracsur.2010.10.034

  View details for PubMedID 21172507

  View details for PubMedCentralID PMC3021252

• Transapical deployment of endovascular thoracic aortic stent graft for an ascending aortic pseudoaneurysm. The Annals of thoracic surgery Szeto, W. Y., Moser, W. G., Desai, N. D., Milewski, R. K., Cheung, A. T., Pochettino, A., Bavaria, J. E. 2010; 89 (2): 616-8

  Abstract

  We report a case of a patient with a history of previous coronary artery bypass grafting undergoing endovascular aortic repair of a large pseudoaneurysm in the ascending aorta. Due to the limitations of the current technology, the endograft was deployed through a left ventricular transapical approach by using a left mini-thoracotomy.

  View details for DOI 10.1016/j.athoracsur.2009.06.090

  View details for PubMedID 20103359

• Spinal cord protection and thoracic aortic surgery. Current opinion in anaesthesiology Sinha, A. C., Cheung, A. T. 2010; 23 (1): 95-102

  Abstract

  Spinal cord ischemia remains an important complication of open surgical and endovascular stent graft repair of thoracic and thoracoabdominal aortic aneurysm despite advances in operative technique. Identification of risk factors and interventions to prevent and treat spinal cord ischemia has the potential to prevent spinal cord infarction and the morbidity and mortality associated with paraplegia.Risk factors for spinal cord ischemia are aneurysm extent, open surgical repair, prior distal aortic operations, and perioperative hypotension. Augmenting spinal cord perfusion by increasing arterial pressure, lumbar cerebrospinal fluid drainage, and reattachment of segmental arteries are effective for the treatment of spinal cord ischemia. Early detection of spinal cord ischemia by intraoperative neurophysiologic monitoring and postoperative neurological examination is important to enable immediate treatment to prevent permanent paraplegia.Permanent paraplegia after thoracic and thoracoabdominal aortic aneurysm repair can be prevented in many high-risk patients by early detection and immediate treatment of spinal cord ischemia before it evolves to infarction. The mortality and morbidity associated with permanent paraplegia justifies the risks and uncertainties associated with established therapeutic interventions.

  View details for DOI 10.1097/ACO.0b013e3283348975

  View details for PubMedID 19920758

• Pro: ultrasound should be the standard of care for central catheter insertion. Journal of cardiothoracic and vascular anesthesia Augoustides, J. G., Cheung, A. T. 2009; 23 (5): 720-4

  View details for DOI 10.1053/j.jvca.2009.06.012

  View details for PubMedID 19686963

• Invited commentary. The Annals of thoracic surgery Sinha, A. C., Cheung, A. T. 2009; 87 (5): 1474

  View details for DOI 10.1016/j.athoracsur.2009.03.044

  View details for PubMedID 19379887

• Neurologic Outcomes from High Risk Descending Thoracic and Thoracoabdominal Aortic Operations in the Era of Endovascular Repair NEUROCRITICAL CARE Messe, S. R., Bavaria, J. E., Mullen, M., Cheung, A. T., Davis, R., Augoustides, J. G., Gutsche, J., Woo, E. Y., Szeto, W. Y., Pochettino, A., Woo, Y. J., Kasner, S. E., McGarvey, M. 2008; 9 (3): 344-351

  Abstract

  Spinal cord ischemia and stroke are recognized complications of descending thoracic (DTA) and thoracoabdominal aortic (TAA) operations. However, there are limited data available on outcomes since the advent of thoracic endovascular aortic repair (TEVAR).We reviewed charts from consecutive patients who underwent open DTA and TAA operations, excluding type IV repair, from January, 2000 through April, 2005.A total of 224 open DTA and TAA operations were included in the analysis. During this period 108 additional patients received TEVAR, accounting for 66% of all DTA repairs. Among the 224 patients who underwent open surgery, 63 patients (28%) developed spinal ischemia postprocedure, 13 (6%) had a stroke, and 9 (4%) had both. The 30 day in-hospital mortality was 18%. Neurologic complications were strongly associated with mortality: 64% of patients with stroke died compared to 17% without (P < 0.001) and 39% of patients with spinal ischemia died compared to 14% without (P < 0.001). At discharge, 29% had a poor outcome from surgery, defined as death or moderate-to-severe neurologic disability. A multivariable logistic regression incorporating characteristics known prior to surgery resulted in a score to stratify risk of poor outcome by giving one point each for age > or =60, history of cerebrovascular disease, Crawford extent II or III repair, and acute rupture. Patients with score > or =3 had an estimated 60% risk for poor outcome, while those with score < or =1 had an estimated risk of 7-11%.Ischemic neurologic complications were frequent and strongly associated with poor outcomes after open DTA and TAA repair among patients not eligible for TEVAR. Risk of death or neurologic disability can be estimated based on factors known prior to surgery.

  View details for DOI 10.1007/s12028-008-9104-9

  View details for Web of Science ID 000260542100011

  View details for PubMedID 18483880

• The ECLIPSE trials: Comparative studies of clevidipine to nitroglycerin, sodium nitroprusside, and nicardipine for acute hypertension treatment in cardiac surgery patients ANESTHESIA AND ANALGESIA Aronson, S., Dyke, C. M., Stierer, K. A., Levy, J. H., Cheung, A. T., Lumb, P. D., Kereiakes, D. J., Newman, M. F. 2008; 107 (4): 1110-1121

  Abstract

  Acute hypertension during cardiac surgery can be difficult to manage and may adversely affect patient outcomes. Clevidipine is a novel, rapidly acting dihydropyridine L-type calcium channel blocker with an ultrashort half-life that decreases arterial blood pressure (BP). The Evaluation of CLevidipine In the Perioperative Treatment of Hypertension Assessing Safety Events trial (ECLIPSE) was performed to compare the safety and efficacy of clevidipine (CLV) with nitroglycerin (NTG), sodium nitroprusside (SNP), and nicardipine (NIC) in the treatment of perioperative acute hypertension in patients undergoing cardiac surgery.We analyzed data from three prospective, randomized, open-label, parallel comparison studies of CLV to NTG or SNP perioperatively, or NIC postoperatively in patients undergoing cardiac surgery at 61 medical centers. Of the 1964 patients enrolled, 1512 met postrandomization inclusion criteria of requiring acute treatment of hypertension based on clinical criteria. The patients were randomized 1:1 for each of the three parallel comparator treatment groups. The primary outcome was the incidence of death, myocardial infarction, stroke or renal dysfunction at 30 days. Adequacy and precision of BP control was evaluated and is reported as a secondary outcome.There was no difference in the incidence of myocardial infarction, stroke or renal dysfunction for CLV-treated patients compared with the other treatment groups. There was no difference in mortality rates between the CLV, NTG or NIC groups. Mortality was significantly higher, though, for SNP-treated patients compared with CLV-treated patients (P=0.04). CLV was more effective compared with NTG (P=0.0006) or SNP (P=0.003) in maintaining BP within the prespecified BP range. CLV was equivalent to NIC in keeping patients within a prespecified BP range; however, when BP range was narrowed, CLV was associated with fewer BP excursions beyond these BP limits compared with NIC.CLV is a safe and effective treatment for acute hypertension in patients undergoing cardiac surgery.

  View details for DOI 10.1213/ane.0b013e31818240db

  View details for Web of Science ID 000259522100006

  View details for PubMedID 18806012

• Endovascular stenting of thoracic aortic aneurysm. Anesthesiology clinics Gutsche, J. T., Szeto, W., Cheung, A. T. 2008; 26 (3): 481-499

  Abstract

  In 2005, the findings of the multicenter Gore Tag study led to United States Food and Drug Administration approval for endovascular repair of thoracic aortic aneurysms (TEVAR). TEVAR provides a therapeutic option for patients who have thoracic aortic aneurysm and for the treatment of type B aortic dissection with malperfusion. Spinal cord ischemia and stroke are recognized neurologic complications of TEVAR. Identification of high-risk patients combined with targeted anesthetic and perioperative management may decrease the risk of neurologic complications after TEVAR.

  View details for DOI 10.1016/j.anclin.2008.03.006

  View details for PubMedID 18765219

• The treatment of spinal cord ischemia following thoracic endovascular aortic repair. Neurocritical care McGarvey, M. L., Mullen, M. T., Woo, E. Y., Bavaria, J. E., Augoustides, Y. G., Messé, S. R., Cheung, A. T. 2007; 6 (1): 35-9

  Abstract

  Thoracic endovascular aortic repair (TEVAR) is a promising alternative to the traditional open surgical approach, though spinal cord ischemia remains a challenging complication. Spinal cord ischemia has been treated using lumbar cerebral spinal fluid (CSF) drainage.We report a case of delayed spinal cord ischemia that was successfully treated with vasopressor therapy alone, supporting aggressive blood pressure augmentation as a primary intervention to increase spinal cord perfusion.The pathophysiology of spinal cord ischemia after TEVAR is presented along with our treatment protocol.

  View details for DOI 10.1385/NCC:6:1:35

  View details for PubMedID 17356189

• Risk factors for perioperative stroke after thoracic endovascular aortic repair 43rd Annual Meeting of the Society-of-Thoracic-Surgeons Gutsche, J. T., Cheung, A. T., McGarvey, M. L., Moser, W. G., Szeto, W., Carpenter, J. P., Fairman, R. M., Pochettino, A., Bavaria, J. E. ELSEVIER SCIENCE INC. 2007: 1195–1200

  Abstract

  Stroke has emerged as an important complication of thoracic endovascular aortic repair (TEVAR). Identifying risk factors for stroke is important to define the risks of this procedure.All neurologic complications were analyzed in a prospective database of patients in thoracic aortic stent graft trials from 1999 to 2006. Serial neurological examination was performed. Stroke was defined as any new onset focal neurologic deficit.The TEVAR was performed on 171 patients; 52 had lesions requiring coverage of the proximal descending thoracic aorta (extent A), 50 requiring coverage of the distal descending aorta (extent B), and 69 requiring coverage of the entire descending thoracic aorta (extent C). The incidence of stroke was 5.8%. Eighty-nine percent (8 of 9) of strokes occurred within 24 hours of operation. Stroke was associated with a 33% in-hospital mortality rate. Risk factors identified for stroke included prior stroke (odds ratio [OR] 9.4, confidence interval [CI] 2.3 to 38.1, p = 0.002) and extent A or C coverage (OR 5.5, CI 1.7-12.5, p = 0.001). The stroke rate in patients with both prior stroke and extent A or C coverage was 27.7%. Severe atheromatous disease involving the aortic arch by computed tomographic scan was strongly associated with perioperative stroke (OR = 14.8, CI 1.7 to 675.6, p = 0.0016). Transesophageal echocardiography demonstrated mobile atheroma in two patients with stroke.Stroke after TEVAR was associated with a high mortality. The TEVAR of the proximal descending aorta (extent A or C) in patients with a history of stroke had the highest perioperative stroke rate. These risk factors, together with high grade aortic atheroma of the aortic arch, predicted a high probability for cerebral embolization and can be used to identify patients at high risk for stroke as a consequence of TEVAR.

  View details for DOI 10.1016/j.athoracsur.2007.04.128

  View details for Web of Science ID 000249595600021

  View details for PubMedID 17888969

• Management of neurologic complications of thoracic aortic surgery. Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society McGarvey, M. L., Cheung, A. T., Szeto, W., Messe, S. R. 2007; 24 (4): 336-43

  Abstract

  Neurologic complications of thoracic aortic surgery are strongly associated with increased morbidity and mortality. Identifying preoperative risk factors for neurologic injury may enable us to refine our perioperative approach, and to lessen or avoid these complications. Methods to identify stroke and spinal ischemia intraoperatively such as neurophysiologic monitoring may enable us to improve outcomes in these patients by immediately instituting measures to improve brain and spine perfusion. The development of both protocols and therapies to treat these complications has allowed us to mitigate and, at times, reverse neurologic injury both intraoperatively and postoperatively.

  View details for DOI 10.1097/WNP.0b013e31811ec0b0

  View details for PubMedID 17938602

• Cardiopulmonary bypass, hemolysis, and nitroprusside-induced cyanide production ANESTHESIA AND ANALGESIA Cheung, A. T., Cruz-Shiavone, G. E., Meng, Q. C., Pochettino, A., Augoustides, J. A., Bavaria, J. E., Ochroch, E. A. 2007; 105 (1): 29-33

  Abstract

  Cyanide toxicity is a complication of sodium nitroprusside administration. Cardiac surgery may increase the risk of cyanide toxicity, because hemolysis during cardiopulmonary bypass (CPB) may catalyze the release of free cyanide from sodium nitroprusside.We obtained serial blood specimens from 25 cardiac surgical patients during CPB. Plasma specimens were analyzed for free hemoglobin concentration and ability to generate free cyanide anion upon exposure to sodium nitroprusside.Hemolysis based on plasma-free hemoglobin concentration increased over time during CPB at an average rate of 0.27 mg x dL(-1) x min(-1) (P < 0.001). The concentration of free cyanide generated by the addition of sodium nitroprusside to the plasma samples was directly related to the plasma-free hemoglobin concentration (P < 0.001).CPB-associated hemolysis and free hemoglobin release accelerated the immediate release of free cyanide from sodium nitroprusside. These in vitro findings suggest that cardiac surgical patients may be at increased risk of cyanide toxicity in response to the perioperative administration of sodium nitroprusside.

  View details for DOI 10.1213/01.ane.0000264078.34514.32

  View details for Web of Science ID 000247444800009

  View details for PubMedID 17578949

• Images in cardiovascular medicine. Rib perforation from a right ventricular pacemaker lead. Circulation Singhal, S., Cooper, J. M., Cheung, A. T., Acker, M. A. 2007; 115 (14): e391-2

  View details for PubMedID 17420357

• Echocardiographic evidence of the Brockenbrough-Braunwald-Morrow sign after mitral valve repair. Anesthesia and analgesia Stearns, J. D., Szeto, W. Y., Cheung, A. T. 2007; 104 (3): 502-3

  View details for DOI 10.1213/01.ane.0000255221.55774.3b

  View details for PubMedID 17312196

• Techniques for preserving vertebral artery perfusion during thoracic aortic stent grafting requiring aortic arch landing. Vascular and endovascular surgery Woo, E. Y., Bavaria, J. E., Pochettino, A., Gleason, T. G., Woo, Y. J., Velazquez, O. C., Carpenter, J. P., Cheung, A. T., Fairman, R. M. 2006; 40 (5): 367-373

  Abstract

  Thoracic endografting offers many advantages over open repair. However, delivery of the device can be difficult and may necessitate adjunctive procedures. We describe our techniques for preserving perfusion to the left subclavian artery despite endograft coverage to obtain a proximal seal zone. We reviewed our experience with the Talent thoracic stent graft (Medtronic, Santa Rosa, CA). From 1999 to 2003, 49 patients received this device (29 men, 20 women). Seventeen patients required adjunctive procedures to facilitate proximal graft placement. We performed left subclavian-to-left common carotid artery transposition (6), left common carotid-to-left subclavian artery bypass with ligation proximal to the vertebral artery (7), and left common carotid-to-left subclavian artery bypass with proximal coil embolization (4). Patients who had anatomy unfavorable to transposition or bypass with proximal ligation (large aneurysms or proximal vertebral artery origin) were treated with coil embolization of the proximal left subclavian artery in order to prevent subsequent type II endoleaks. Technical success rate of the carotid subclavian bypass was 100%. Patient follow-up ranged from 3 to 48 months with a mean of 12 months. Six patients had follow-up <6 months owing to recent graft placement. Primary patency was 100%. No neurologic events occurred during the procedure or upon follow-up. One patient had a transient chyle leak that spontaneously resolved in 24 hours. Another patient had a phrenic nerve paresis that resolved after 3 weeks. We believe that it is important to maintain patency of the vertebral artery specifically when a patent right vertebral system and an intact basilar artery is not demonstrated. Furthermore, we describe a novel technique of coil embolization of the proximal left subclavian artery in conjunction with left common carotid-to-left subclavian artery bypass. This circumvents the need for potentially hazardous mediastinal dissection and ligation of the proximal left subclavian artery in cases of large proximal aneurysms or unfavorable vertebral artery anatomy.

  View details for PubMedID 17038570

• Exploring an optimum intra/postoperative management strategy for acute hypertension in the cardiac surgery patient. Journal of cardiac surgery Cheung, A. T. 2006; 21 Suppl 1: S8-S14

  Abstract

  An estimated 50% of patients undergoing routine cardiac surgery require intravenous antihypertensive therapy to manage life-threatening arterial bleeding, myocardial ischemia, or cardiac failure in the perioperative period. Managing hypertension in this setting can be challenging because of the need to reduce blood pressure while maintaining adequate end organ perfusion. Hypotensive episodes can increase the risk of cardiac complications and end organ hypoperfusion, particularly in patients whose underlying cardiovascular disease has altered autoregulation of blood flow. To decrease the risk of hypertensive or hypotensive episodes, blood pressure is monitored continuously, and short-acting intravenous antihypertensive agents are administered in an effort to target a mean arterial pressure generally within 20% of the patient's baseline value. Efforts to optimize end organ perfusion and avoid recognized adverse drug effects may influence the choice of antihypertensive agents. The ideal agent for postoperative hypertension should have a rapid onset of action, be highly vascular selective, and be rapidly reversible. In addition, it should be safe, with little risk of overshoot hypotension or adverse drug reaction. Precise management of arterial pressure in the perioperative period has the potential to improve clinical outcome by avoiding hypotensive episodes, ensuring adequate end organ perfusion, decreasing the risk of adverse drug effects, and serving as a bridge to definitive long-term therapy for essential hypertension.

  View details for DOI 10.1111/j.1540-8191.2006.00214.x

  View details for PubMedID 16492294

• Perioperative outcome in adults undergoing elective deep hypothermic circulatory arrest with retrograde cerebral perfusion in proximal aortic arch repair: Evaluation of protocol-based care JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Appoo, J. J., Augoustides, J. G., Pochettino, A., Savino, J. S., McGarvey, M. L., Cowie, D. C., Gambone, A. J., Harris, H., Cheung, A. T., Bavaria, J. E. 2006; 20 (1): 3-7

  Abstract

  The purpose of this study was to describe perioperative outcome in adults undergoing elective proximal aortic arch repair with protocol-based deep hypothermic circulatory arrest (DHCA) with retrograde cerebral perfusion (RCP).Retrospective and observational.Cardiothoracic operating rooms and intensive care unit.Seventy-nine consecutive adults undergoing elective proximal aortic arch repair with DHCA (1999-2001).None.Average age of the patients was 64.9 years. Mean circulatory arrest time was 30.4 +/- 8.5 minutes. Perioperative mortality was 7.6%. Perioperative stroke incidence was 3.8%. Tracheal extubation was successful in 87.3% of patients within 24 hours of operation. Of the cohort, 80.8% were discharged from the intensive care unit within 72 hours of surgery. Median length of hospital stay was 7.4 days. Repeat mediastinal exploration because of bleeding occurred in 3.8% of patients. Although perioperative renal dysfunction (defined as >1.5-fold increase in plasma creatinine concentration) developed in 24.0% of patients, only 3.8% required dialysis.The above parameters establish a baseline incidence for major perioperative complications in adults undergoing elective DHCA with RCP for elective proximal aortic arch repair. In approaching the open aortic arch for short periods of circulatory arrest, deep hypothermia with adjunctive RCP is safe and effective.

  View details for DOI 10.1053/j.jvca.2005.08.005

  View details for Web of Science ID 000235490300002

  View details for PubMedID 16458205

• Clinical predictors for prolonged intensive care unit stay in adults undergoing thoracic aortic surgery requiring deep hypothermic circulatory arrest. Journal of cardiothoracic and vascular anesthesia Augoustides, J. G., Pochettino, A., Ochroch, E. A., Cowie, D., McGarvey, M. L., Weiner, J., Gambone, A. J., Pinchasik, D., Cheung, A. T., Bavaria, J. E. 2006; 20 (1): 8-13

  Abstract

  The purpose of this study was to describe clinical predictors for prolonged length of stay in the intensive care unit (PLOS-ICU) after adult thoracic aortic surgery requiring standardized deep hypothermic circulatory arrest (DHCA); and to determine the incidence of PLOS-ICU after DHCA, univariate predictors for PLOS-ICU, and multivariate predictors for PLOS-ICU.A retrospective and observational study. PLOS-ICU was defined as longer than 5 days in the ICU.Cardiothoracic operating rooms and the ICU.All adults requiring thoracic aortic repair with DHCA INTERVENTIONS: None.The cohort size was 144. The incidence of PLOS-ICU was 27.8%. The mortality rate was 11.1%. Univariate predictors for PLOS-ICU were age, stroke, DHCA duration, vasopressor dependence >72 hours, mediastinal re-exploration for bleeding, and renal dysfunction. Multivariate predictors for PLOS-ICU were stroke, vasopressor dependence >72 hours, and renal dysfunction.PLOS-ICU after DHCA is common. The identified multivariate predictors merit further hypothesis-driven research to enhance perioperative protection of the brain, kidney, and cardiovascular system.

  View details for DOI 10.1053/j.jvca.2005.07.031

  View details for PubMedID 16458206

• Strategies to manage paraplegia risk after endovascular stent repair of descending thoracic aortic aneurysms 41st Annual Meeting of the Society-of-Thoracic-Surgeons Cheung, A. T., Pochettino, A., McGarvey, M. L., Appoo, J. J., Fairman, R. M., Carpenter, J. P., Moser, W. G., Woo, E. Y., Bavaria, J. E. ELSEVIER SCIENCE INC. 2005: 1280–89

  Abstract

  Paraplegia is a recognized complication after endovascular stent repair of descending thoracic aortic aneurysms. A management algorithm employing neurologic assessment, somatosensory evoked potential monitoring, arterial pressure augmentation, and cerebrospinal fluid drainage evolved to decrease the risk of postoperative paraplegia.Patients in thoracic aortic aneurysm stent trials from 1999 to 2004 were analyzed for paraplegic complications. Lower extremity strength was assessed after anesthesia and in the intensive care unit. A loss of lower extremity somatosensory evoked potential or lower extremity strength was treated emergently to maintain a mean arterial pressure 90 mmHg or greater and a cerebrospinal fluid pressure 10 mm Hg or less.Seventy-five patients (male = 49, female = 26, age = 75 +/- 7.4 years) had descending thoracic aortic aneurysms repaired with endovascular stenting. Lumbar cerebrospinal fluid drainage (n = 23) and somatosensory evoked potential monitoring (n = 15) were performed selectively in patients with significant aneurysm extent or with prior abdominal aortic aneurysm repair (n = 17). Spinal cord ischemia occurred in 5 patients (6.6%); two had lower extremity somatosensory evoked potential loss after stent deployment and 4 developed delayed-onset paraplegia. Two had full recovery in response to arterial pressure augmentation alone. Two had full recovery and one had near-complete recovery in response to arterial pressure augmentation and cerebrospinal fluid drainage. Spinal cord ischemia was associated with retroperitoneal bleed (n = 1), prior abdominal aortic aneurysm repair (n = 2), iliac artery injury (n = 1), and atheroembolism (n = 1).Early detection and intervention to augment spinal cord perfusion pressure was effective for decreasing the magnitude of injury or preventing permanent paraplegia from spinal cord ischemia after endovascular stent repair of descending thoracic aortic aneurysm. Routine somatosensory evoked potential monitoring, serial neurologic assessment, arterial pressure augmentation, and cerebrospinal fluid drainage may benefit patients at risk for paraplegia.

  View details for DOI 10.1016/j.athoracsur.2005.04.027

  View details for Web of Science ID 000232442100019

  View details for PubMedID 16181855

• Active thermoregulation improves outcome of off-pump coronary artery bypass. Asian cardiovascular & thoracic annals Woo, Y. J., Atluri, P., Grand, T. J., Hsu, V. M., Cheung, A. 2005; 13 (2): 157-160

  Abstract

  During off-pump coronary artery bypass grafting, hypothermia increases vasoconstriction, myocardial afterload, coagulopathy and postoperative bleeding. Traditional thermoregulatory techniques do not maintain core body temperature intraoperatively. The efficacy of a commercially available, computer-controlled, water-circulating, dorsal surface, active warming system for thermoregulatory control was evaluated. All patients who underwent non-emergency off-pump coronary bypass grafting by a single surgeon in a 1-year period were studied: the thermoregulation device was used in 50 cases and unavailable for use in 19. The patients who underwent active thermoregulation demonstrated significantly improved core body temperatures compared to the controls: lowest intraoperative, 35.8 degrees C +/- 0.1 degrees C vs. 35.0 degrees C +/- 0.2 degrees C; immediately postoperative, 36.5 degrees C +/- 0.1 degrees C vs. 35.6 degrees C +/- 0.2 degrees C; and 1-hour postoperative, 36.6 degrees C +/- 0.1 degrees C vs. 35.9 degrees C +/- 0.2 degrees C. Thermoregulated patients had significantly reduced 24-hour chest tube drainage (764 +/- 38 vs. 1227 +/- 183 mL), packed red blood cell transfusions (1.4 +/- 0.2 vs. 3.3 +/- 0.7 units), time to extubation (6.8 +/- 0.5 vs. 11.4 +/- 2.3 hours), intensive care unit stay (1.3 +/- 0.1 vs. 2.0 +/- 0.3 days), and hospital stay (4.3 +/- 0.1 vs. 5.1 +/- 0.3 days).

  View details for PubMedID 15905346

• Apolipoprotein E genotype and S100beta after cardiac surgery: is inflammation the link? Anesthesia and analgesia Kofke, W. A., Cheung, A., Konitzer, P. 2005; 100 (6): 1870

  View details for DOI 10.1213/01.ANE.0000156712.21918.BD

  View details for PubMedID 15920252

• Analysis of the interatrial septum by transesophageal echocardiography in adult cardiac surgical patients: anatomic variants and correlation with patent foramen ovale. Journal of cardiothoracic and vascular anesthesia Augoustides, J. G., Weiss, S. J., Ochroch, A. E., Weiner, J., Mancini, J., Savino, J. S., Cheung, A. T. 2005; 19 (2): 146-9

  Abstract

  The purpose of this study was to document the perioperative prevalence of anatomic variants of the interatrial septum (IAS), to classify atrial septal aneurysm based on mobility pattern, and to correlate anatomic variants of IAS with patent foramen ovale (PFO).A prospective observational study.University hospital (single institution).Patients presenting for cardiac surgery requiring transesophageal echocardiography.Multiplane TEE in 2 atrial views with color-flow Doppler and contrast echocardiography with a provocative respiratory maneuver.The cohort size was 206. PFO prevalence was 30.1%. The prevalence of IAS lipomatous hypertrophy was 43.2%, atrial septal flap (ASF) 43.2%, and atrial septal aneurysm (ASA) 28.6%. ASF and ASA were significantly ( p < 0.05) associated with PFO. Selected ASA subtypes are significantly associated with PFO ( p < 0.05).IAS anatomic variants are common in adult cardiac surgical patients undergoing multiplane TEE. The presence of ASF and ASA predicts enhanced PFO detection. ASA mobility patterns significantly correlate ( p < 0.05) with the presence of PFO.

  View details for PubMedID 15868518

• Diagnosis of patent foramen ovale with multiplane transesophageal echocardiography in adult cardiac surgical patients. Journal of cardiothoracic and vascular anesthesia Augoustides, J. G., Weiss, S. J., Weiner, J., Mancini, J., Savino, J. S., Cheung, A. T. 2004; 18 (6): 725-30

  Abstract

  To evaluate multiplane transesophageal echocardiography (TEE) for detection of patent foramen ovale (PFO) and to compare multiplane TEE with visual inspection (VI) for PFO detection.A prospective observational study.University hospital (single institution).Patients presenting for cardiac surgery requiring TEE.Multiplane TEE including 2 atrial views with color-flow Doppler (CFD) and contrast echocardiography (CE) with a provocative respiratory maneuver (PRM) and comparison of multiplane TEE and VI with respect to PFO detection.The cohort size was 187. PFO prevalence was 27.3%. CFD with serial decrease of the Nyquist limit detected 51% of all PFO: 41.2% in the bicaval view alone, 27.5% in the 4-chamber view alone, and 9.8% in both views. CE detected 78.4% of all PFO: 72.5% with PRM, 45.1% with no PRM, and 27.4% with/without PRM. PFO detection by multiplane TEE and visual inspection were correlated in 41 subjects. TEE diagnosed 11 PFO (26.8% prevalence, 3 missed by VI). VI diagnosed 12 PFO (29.3% prevalence, 4 missed by TEE).Multiplane TEE is a gold standard for detection of PFO. Despite advances in TEE technology, 2-dimensional imaging does not detect all PFO. To maximize PFO detection, multiple TEE modalities are required in multiple views, despite a low Nyquist limit for CFD or a PRM for CE. Even though multiplane TEE is equivalent to VI for PFO detection, the discrepancy rate may be an important consideration in the individual case.

  View details for DOI 10.1053/j.jvca.2004.08.009

  View details for PubMedID 15650981

• The effect of apolipoprotein E genotype on neuron specific enolase and S-100beta levels after cardiac surgery. Anesthesia and analgesia Kofke, W. A., Konitzer, P., Meng, Q. C., Guo, J., Cheung, A. 2004; 99 (5): 1323-5; table of contents

  Abstract

  We tested the hypothesis that two biochemical markers of brain injury would be increased after cardiac surgery in patients with the apolipoprotein (Apo) epsilon4 allele. Arterial blood samples were drawn before and 8 and 24 h after induction of anesthesia and later assayed for neuron specific enolase (NSE), S-100beta, and apoE genotype. There was a highly significant temporal effect with increases in NSE (2.2 +/- 1.6 ng/L to 11.8 +/- 8.9 ng/L; P < 0.0001) (mean +/- sd) and S-100beta (0.15 +/- 0.1 microg/L to 0.45 +/- 0.42 microg/L, P < 0.0001). At 8 and 24 h after induction of anesthesia S-100beta (0.28 +/- 0.18 microg/L versus 0.91 +/- 0.54 microg/L; P =0.004) and NSE (8.6 +/- 5.6 ng/L versus 19.0 +/- 19.7 ng/L; P = 0.02) levels, respectively, were higher in patients with the Apoepsilon4 allele. Patients with the Apoepsilon4 allele may be more susceptible to perioperative neural insults.

  View details for DOI 10.1213/01.ANE.0000135345.03635.6A

  View details for PubMedID 15502024

• Pro: Retrograde cerebral perfusion is useful for deep hypothermic circulatory arrest. Journal of cardiothoracic and vascular anesthesia Pochettino, A., Cheung, A. T. 2003; 17 (6): 764-7

  View details for PubMedID 14689421

• Perioperative changes in cerebral blood flow after cardiac surgery: influence of anemia and aging. The Annals of thoracic surgery Floyd, T. F., McGarvey, M., Ochroch, E. A., Cheung, A. T., Augoustides, J. A., Bavaria, J. E., Acker, M. A., Pochettino, A., Detre, J. A. 2003; 76 (6): 2037-42

  Abstract

  Stroke occurs in 2% to 5% and cognitive dysfunction occurs acutely in 60% to 80% of patients early after cardiac surgery. Both may have long-term consequences. Research into mechanisms behind these sequelae has been focused intraoperatively, although there is little reason to believe that injury is limited to this period. Aging prominently increases the incidence of these sequelae. Anemia with cardiac surgery is acute and severe, should cause an increase in cerebral blood flow (CBF), and may impact stroke and cognitive function in this setting. To better understand changes in perioperative CBF physiology we have measured changes in CBF and the influence of anemia and aging on these changes.Cerebral blood flow was measured using the noninvasive continuous arterial spin labeling perfusion magnetic resonance imaging method. Cerebral blood flow, mean arterial pressure, hemoglobin, hemoglobin oxygen saturation, and cardiopulmonary bypass time were recorded in 12 subjects before and 6 +/- 2 days after cardiac surgery.Cerebral blood flow increased from 44.6 +/- 15.6 mL100 g(-1)min(-1) to 64.4 +/- 20.1 mL100 g(-1)min(-1) after cardiac surgery, or 49.1% +/- 26.7%, (p < 0.0001). The absolute change in CBF (DeltaCBF) was predicted by the following regression model: DeltaCBF = -55 + 0.64(Age) + 0.53(CBF(Pre)) -3.3(DeltaHgb); R(2) = 0.81; p = 0.003, where CBF(Pre) is the baseline preoperative CBF and DeltaHgb is the change in hemoglobin from preoperative to postoperative periods.Cerebral blood flow increases after cardiac surgery, and anemia appears to be an important cause. Age appears also to be an important covariate, with advancing age further increasing the magnitude of this hyperemia. The interrelationship of aging and anemia, in determining perioperative changes in CBF, and potentially cerebral oxygenation, may have important implications for the understanding of perioperative stroke and cognitive dysfunction after cardiac surgery.

  View details for PubMedID 14667637

• Safety of lumbar drains in thoracic aortic operations performed with extracorporeal circulation 39th Annual Meeting of the Society-of-Thoracic-Surgeons Cheung, A. T., Pochettino, A., Guvakov, D. V., Weiss, S. J., Shanmugan, S., Bavaria, J. E. ELSEVIER SCIENCE INC. 2003: 1190–96

  Abstract

  The safety of cerebrospinal fluid (CSF) drainage in thoracic aortic surgery using extracorporeal circulation (ECC) with systemic heparinization has not been established.Four hundred thirty-two patients had descending thoracic or thoracoabdominal aortic repair between 1993 and 2002. One hundred sixty-two of those patients (age range, 67 +/- 13 years) had repairs performed with ECC, systemic anticoagulation, and lumbar CSF drainage. Repairs performed without CSF drainage, without ECC, or by stent graft (n = 53) were excluded. The CSF catheters were inserted at L3 to L5. Cerebrospinal fluid was drained to maintain pressures of 10 to 12 mm Hg. In the absence of neurologic deficit or coagulopathy, the catheters were capped at 24 hours and removed at 48 hours. Cerebrospinal fluid drainage was continued beyond 24 hours for delayed onset paraparesis.Cerebrospinal fluid drains were used in 135 thoracoabdominal aortic aneurysms (extent I, n = 63; extent II, n = 25; extent III, n = 39; extent IV, n = 8) and 27 descending thoracic aortic repairs (aneurysm, n = 24; traumatic aortic injury, n = 2; aortic coarctation, n = 1). Partial left heart bypass was used in 132 patients, full cardiopulmonary bypass without deep hypothermic circulatory arrest in 5, and cardiopulmonary bypass with adjunctive deep hypothermic circulatory arrest in 25. Time between catheter insertion and anticoagulation was 153 +/- 60 minutes. Heparin achieved an average maximum activated clotting time of 528 +/- 192 seconds. Average ECC time was 114 +/- 77 minutes. Average deep hypothermic circulatory arrest time was 40 +/- 12 minutes. Mortality was 14.1% (23 of 162), and permanent paraplegia was 4.9% (8 of 162). No epidural or spinal hematoma was observed. Six (3.7%) patients had catheter-related complications (temporary abducens nerve palsy [n = 1]; retained catheter fragments [n = 2]; retained catheter fragment and meningitis [n = 1]; isolated meningitis [n = 1]; and spinal headache [n = 1]).The CSF drainage in thoracic aortic surgery using ECC with full anticoagulation did not result in hemorrhagic complications. The permanent paraplegia rate in this complex patient population consisting of combined distal arch, thoracoabdominal aortic procedures were low, and lumbar CSF catheter-related complications had no permanent sequelae.

  View details for Web of Science ID 000185717900050

  View details for PubMedID 14530010

• Acute circulatory actions of intravenous amiodarone loading in cardiac surgical patients. The Annals of thoracic surgery Cheung, A. T., Weiss, S. J., Savino, J. S., Levy, W. J., Augoustides, J. G., Harrington, A., Gardner, T. J. 2003; 76 (2): 535-41

  Abstract

  The duration, severity, and cause of hypotension after intravenous amiodarone has not been well characterized in anesthetized cardiac surgical patients. Because amiodarone is tolerated in patients with advanced cardiac disease, we hypothesized that left ventricular systolic performance is preserved despite hypotension during amiodarone loading.In a prospective double-blind trial, 30 patients undergoing coronary artery bypass graft (CABG) surgery were randomly assigned to receive intravenous amiodarone (n = 15) or placebo (n = 15). Cardiac output (CO), mixed venous oxygen saturation (SVO), arterial blood pressure (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP]), pulmonary artery pressure, and central venous pressure (CVP) were recorded. Transesophageal echocardiographic left ventricular end-diastolic area (EDA), end-systolic area (ESA), fractional area change (FAC), and end-systolic wall stress (ESWS) were measured every 5 minutes.Mean arterial pressure, SBP, and DBP decreased over time after drug administration in both groups (p < 0.05). At 6 minutes, amiodarone decreased the MAP by 14 mm Hg (p = 0.004) and placebo decreased the MAP by 4 mm Hg. The change in MAP, SBP, and DBP between groups was statistically different for the first 15 minutes after drug administration. Hypotension requiring intervention occurred in 3 of 15 after amiodarone and 0 of 15 after placebo (p = 0.22). The mean heart rate was 11.5 beats per minute less after amiodarone (p < 0.02), but pulmonary artery pressure, CVP, SVO, and FAC were not different between groups.Intravenous amiodarone decreased heart rate and caused a significant, but transient decrease in arterial pressure in the first 15 minutes after administration. Left ventricular performance was maintained suggesting that selective arterial vasodilation was the primary cause of drug-induced hypotension.

  View details for PubMedID 12902100

• Utility of the neurologic intensive care evaluation (NICE) in detecting neurologic deficit after cardiac operations--a pilot study. Medical science monitor Baker, S., Beauchamp, K., Ballinghoff, J., Escherich, A., Cheung, A. T., Stecker, M. M. 2003; 9 (5): CR151-6

  Abstract

  Neurocognitive changes are common after cardiac operations. The acute post-operative period is a critical time when significant neurologic changes may be detected and appropriate therapy initiated promptly. Formal neuropsychologic testing in this situation however is impractical so other means of early detection are required. The goal of this preliminary study was to determine whether simple, standardized, serial nursing neurologic evaluations using the Neurologic Intensive Care Evaluation (NICE) could be helpful in screening patients for neurologic injury in the immediate post-operative period.Details of the intra-operative and post-operative anesthetic management were obtained during report and nurses subsequently scored acute post-operative patients in the CTSICU using the NICE every half hour for the first five hours. Finally, a chart review was performed to determine the neurologic outcome of the patients.The time to achieve the lower NICE scores which reflect mainly brainstem function was the same whereas the time to achieve NICE scores>4 was prolonged in patients with neurocognitive dysfunction. The effect of intra-operative factors on the times to achieve NICE scores was different for the higher and lower scores. The times to reach NICE scores correlated with outcome variables including the time in ICU and time of intubation.Standardized, serial nursing neurologic assessments of post-operative cardiac patients may be a useful tool for early identification of patients with neurologic injury. They may also provide useful information complementing the data obtained from detailed neuropsychologic testing on the neurologic effects of cardiac operations.

  View details for PubMedID 12761449

• Interventions for reversing delayed-onset postoperative paraplegia after thoracic aortic reconstruction 38th Annual Meeting of the Society-of-Thoracic-Surgeons Cheung, A. T., Weiss, S. J., McGarvey, M. L., Stecker, M. M., Hogan, M. S., Escherich, A., Bavaria, J. E. ELSEVIER SCIENCE INC. 2002: 413–19

  Abstract

  Delayed postoperative paraplegia is a recognized complication of thoracic (TAA) or thoracoabdominal aortic aneurysm (TAAA) repair. The purpose of this study was to evaluate the effectiveness of interventions to treat delayed-onset paraplegia.Between January 1, 2000 and August 31, 2001, 99 patients underwent surgical repair of TAA, Crawford type I, II, or III TAAA. Standard intraoperative management included distal aortic perfusion and cerebrospinal fluid (CSF) drainage unless contraindicated. Therapeutic interventions to treat delayed paraplegia included lumbar CSF drainage and vasopressor therapy.Three of the 99 patients had paraplegia upon awakening. Delayed-onset paraplegia occurred in 8 patients, 2 of whom had recurrent episodes. In those 8 patients, the initial episode occurred at a median of 21.6 hours (range 6.4 to 110.0 hours) after surgery and the second episode averaged 176 hours after surgery. At the onset of paraplegia, the average mean arterial pressure was 74 mm Hg and CSF pressure was 14 mm Hg. Three of the 8 patients had a functioning CSF catheter at the onset and the other 5 patients had catheters subsequently placed. Therapeutic interventions increased blood pressure to a mean arterial pressure of 95 mm Hg and decreased CSF pressure to 10 mm Hg. Five of the 8 patients with delayed-onset paraplegia made a full neurologic recovery and 3 had partial recovery.Patients with delayed-onset paraplegia had an increased chance of recovery as compared with those patients in whom paraplegia was diagnosed upon emergence from anesthesia. Acute interventions directed to increase spinal cord perfusion by increasing systemic blood pressure and decreasing CSF pressure were effective for the reversal of delayed onset of paraplegia after TAA or TAAA repair, resulting in an overall 3% incidence of permanent paraplegia and 3% incidence of residual paraparesis.

  View details for Web of Science ID 000177320600030

  View details for PubMedID 12173822

• Successful treatment of delayed onset paraplegia after suprarenal abdominal aortic aneurysm repair. Anesthesiology Weiss, S. J., Hogan, M. S., McGarvey, M. L., Carpenter, J. P., Cheung, A. T. 2002; 97 (2): 504-6

  View details for PubMedID 12151944

• Life-threatening hyperkalemia: a complication of spironolactone for heart failure in a patient with renal insufficiency. Anesthesia and analgesia Hu, Y., Carpenter, J. P., Cheung, A. T. 2002; 95 (1): 39-41, table of contents

  Abstract

  Serum potassium concentration should be measured immediately before operation to detect hyperkalemia in heart failure patients treated with spironolactone. Renal insufficiency, advanced age, potassium supplementation, decompensated congestive heart failure, and a spironolactone dose larger than 25 mg/d increase the risk of hyperkalemia as a consequence of spironolactone therapy.

  View details for PubMedID 12088939

• Anesthesia and temperature effects on somatosensory evoked potentials produced by train stimuli. The International journal of neuroscience Stecker, M. M., Kent, G., Escherich, A., Patterson, T., Cheung, A. T. 2002; 112 (3): 349-69

  Abstract

  To determine the effect of anesthesia, temperature, and stimulus characteristics on the response of upper extremity somatosensory evoked responses (SSEP) to repetitive stimulation.Pairs and trains of electrical stimuli were used to elicit the upper extremity SSEP, and the amplitudes of the N20-P22, N13, and Erb's point potentials produced by each stimulus were measured. The ratio of the amplitude of the response to each stimulus to that produced by the first stimulus in a given train was computed. Recordings were also made directly from the cortical surface in a single patient.There were only minimal effects of anesthesia, temperature, or stimulus characteristics on the amplitude ratios for the N13 and Erb's point potentials. The N20-P22 amplitude ratio demonstrated facilitation with interstimulus intervals in the 20-100 ms range and was markedly reduced with hypothermia. The degree of facilitation was strongly dependent on isoflurane and nitrous oxide concentrations. In response to stimulation with trains of four stimuli, increased amplitudes of the N20-P22 complex were seen maximally with the second response while the third and fourth responses were of lower amplitude.There are strong effects of anesthesia and temperature on the cortical responses to repetitive stimulation of the upper extremity. Speculations on the origin of these effects were made.

  View details for PubMedID 12187784

• Reliability of nurses' neurological assessments in the cardiothoracic surgical intensive care unit. American journal of critical care BEAUCHAMP, K., Baker, S., McDaniel, C., Moser, W., Zalman, D. C., Balinghoff, J., Cheung, A. T., Stecker, M. 2001; 10 (5): 298-305

  Abstract

  Alterations in mental status are common among patients in the cardiothoracic surgical intensive care unit. Changes in mental status can be caused by metabolic factors, medications, or brain injury. In this setting, reliable, serial neurological evaluations are critical for assessing the effectiveness of treatment and the need for additional studies.To estimate the reliability of the Rancho Los Amigos Cognitive Scale and the newly developed Neurologic Intensive Care Evaluation as measures of cognitive function in the cardiothoracic surgical intensive care unit.Nurses used 1 of the 2 scales as part of routine neurological assessments of patients in the cardiothoracic surgical intensive care unit. For each test, scores of different observers were correlated and a reliability estimate formed.Interrater reliability was high for both evaluations (Rancho scale, 0.91; Neurologic Intensive Care Evaluation, 0.94). Correlations between the scores of different pairs of observers were also high (mean rho values, 0.84 for the Rancho scale and 0.77 for the Neurologic Intensive Care Evaluation).Both scales are reliable indicators of the neurological state of patients in the cardiothoracic surgical intensive care unit. These scales measure different, although limited, aspects of cognitive function. Each test was simple to administer and did not take more time than the standard nursing neurological examination. Most of the variability in scoring was related to the different degrees of stimulation used by examiners when assessing patients, not to differences in the interpretation of patients' responses.

  View details for PubMedID 11548562

• Deep hypothermic circulatory arrest: I. Effects of cooling on electroencephalogram and evoked potentials 36th Annual Meeting of the Society-of-Thoracic-Surgeons Stecker, M. M., Cheung, A. T., Pochettino, A., Kent, G. P., Patterson, T., Weiss, S. J., Bavaria, J. E. ELSEVIER SCIENCE INC. 2001: 14–21

  Abstract

  Deep hypothermia is an important cerebral protectant and is critical in procedures requiring circulatory arrest. The purpose of this study was to determine the factors that influence the neurophysiologic changes during cooling before circulatory arrest, in particular the occurrence of electrocerebral silence.In 109 patients undergoing hypothermic circulatory arrest with neurophysiologic monitoring, five electrophysiologic events were selected for detailed study.The mean nasopharyngeal temperature when periodic complexes appeared in the electroencephalogram after cooling was 29.6 degrees C +/- 3 degrees C, electroencephalogram burst-suppression appeared at 24.4 degrees C +/- 4 degrees C, and electrocerebral silence appeared at 17.8 degrees C +/- 4 degrees C. The N20-P22 complex of the somatosensory evoked response disappeared at 21.4 degrees C +/- 4 degrees C, and the somatosensory evoked response N13 wave disappeared at 17.3 degrees C +/- 4 degrees C. The temperatures of these various events were not significantly affected by any patient-specific or surgical variables, although the time to cool to electrocerebral silence was prolonged by high hemoglobin concentrations, low arterial partial pressure of carbon dioxide, and by slow cooling rates. Only 60% of patients demonstrated electrocerebral silence by either a nasopharyngeal temperature of 18 degrees C or a cooling time of 30 minutes.With the high degree of interpatient variability in these neurophysiologic measures, the only absolute predictors of electrocerebral silence were nasopharyngeal temperature below 12.5 degrees C and cooling longer than 50 minutes.

  View details for Web of Science ID 000166457600003

  View details for PubMedID 11216734

• Deep hypothermic circulatory arrest: II. Changes in electroencephalogram and evoked potentials during rewarming 36th Annual Meeting of the Society-of-Thoracic-Surgeons Stecker, M. M., Cheung, A. T., Pochettino, A., Kent, G. P., Patterson, T., Weiss, S. J., Bavaria, J. E. ELSEVIER SCIENCE INC. 2001: 22–28

  Abstract

  Electrophysiologic studies during rewarming after deep hypothermic circulatory arrest probe the state of the brain during this critical period and may provide insight into the neurological effects of circulatory arrest and the neurologic outcome.Electroencephalogram (EEG) and evoked potentials were monitored during rewarming in 109 patients undergoing aortic surgery with hypothermic circulatory arrest.The sequence of neurophysiologic events during rewarming did not mirror the events during cooling. The evoked potentials recovered first followed by EEG burst-suppression and then continuous EEG. The time to recovery of the evoked potentials N20-P22 complex was significantly correlated with the time of circulatory arrest even in patients without postoperative neurologic deficits (r = 0.37, (p = 0.002). The nasopharyngeal temperatures at which continuous EEG activity and the N20-P22 complex returned were strongly correlated (r = 0.44, p = 0.0002; r = 0.41, p = 0.00003) with postoperative neurologic impairment. Specifically, the relative risk for postoperative neurologic impairment increased by a factor of 1.56 (95% CI 1.1 to 2.2) for every degree increase in temperature at which the EEG first became continuous.No trend toward shortened recovery times or improved neurologic outcome was noted with lower temperatures at circulatory arrest, indicating that the process of cooling to electrocerebral silence produced a relatively uniform degree of cerebral protection, independent of the actual nasopharyngeal temperature.

  View details for Web of Science ID 000166457600004

  View details for PubMedID 11216751

• Postoperative neurologic assessment and management of the cardiac surgical patient. Seminars in thoracic and cardiovascular surgery Floyd, T. F., Cheung, A. T., Stecker, M. M. 2000; 12 (4): 337-348

  Abstract

  The neurologic evaluation of patients in the immediate postoperative period and postanesthetic state is unique and challenging. Neurologic assessment is complicated by the lingering residual effects of anesthetics as well as by the effects of narcotic analgesics, anxiolytics, and muscle relaxants, especially in ventilated patients. In this review we examine the suspected causes, clinical manifestations, diagnostic options, and intervention schemes for the common neurologic syndromes seen after cardiac operations.

  View details for PubMedID 11154729

• Nicardipine intravenous bolus dosing for acutely decreasing arterial blood pressure during general anesthesia for cardiac operations: Pharmacokinetics, pharmacodynamics, and associated effects on left ventricular function Annual Meeting of the American-Society-of-Anesthesiologists Cheung, A. T., Guvakov, D. V., Weiss, S. J., Savino, J. S., Salgo, I. S., Meng, Q. C. LIPPINCOTT WILLIAMS & WILKINS. 1999: 1116–23

  Abstract

  The objective of this study was to evaluate the efficacy of nicardipine, a dihydropyridine calcium channel antagonist, administered as an IV bolus dose to acutely decrease arterial pressure in anesthetized cardiac surgical patients. We performed a double-blind, randomized, self-controlled, dose-ranging study in 40 adult cardiac surgical patients to determine the pharmacokinetics and pharmacodynamics of nicardipine 0.25 mg, 0.50 mg, 1.00 mg, and 2.00 mg administered as an IV bolus. Transesophageal echocardiography was used to assess left ventricular preload, afterload, and global systolic function. Plasma nicardipine concentration was measured using high-performance liquid chromatography. Nicardipine selectively decreased arterial pressure in a dose-dependent manner with a maximum response within 100 s and recovery to half the maximum response within 3-7 min without associated changes in heart rate. The decreases in arterial pressure were associated with only small decreases in left ventricular end-systolic wall stress and small increases in global left ventricular systolic function without changes in left ventricular end-diastolic cavity area or cardiac output. The time course for nicardipine bolus was consistent with a two-compartment pharmacokinetic model with rapid redistribution from a small central compartment.Nicardipine was effective for selectively decreasing arterial blood pressure acutely, but had no effects on ventricular preload or cardiac output. The absence of dose-dependent changes in cardiac output, left ventricular systolic performance, and left ventricular afterload despite significant decreases in arterial pressure suggested that nicardipine had a small negative inotropic action.

  View details for Web of Science ID 000083498200008

  View details for PubMedID 10553821

• ASE/SCA guidelines for performing a comprehensive intraoperative multiplane transesophageal echocardiography examination: Recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certification in Perioperative Transesophageal Echocardiography ANESTHESIA AND ANALGESIA Shanewise, J. S., Cheung, A. T., ARONSON, S., Stewart, W. J., Weiss, R. L., Mark, J. B., Savage, R. M., Sears-Rogan, P., Mathew, J. P., Quinones, M. A., Cahalan, M. K., Savino, J. S. 1999; 89 (4): 870-884

  View details for Web of Science ID 000082827700010

  View details for PubMedID 10512257

• Oxygen delivery during retrograde cerebral perfusion in humans ANESTHESIA AND ANALGESIA Cheung, A. T., Bavaria, J. E., Pochettino, A., Weiss, S. J., Barclay, D. K., Stecker, M. M. 1999; 88 (1): 8-15

  Abstract

  Retrograde cerebral perfusion (RCP) potentially delivers metabolic substrate to the brain during surgery using hypothermic circulatory arrest (HCA). Serial measurements of O2 extraction ratio (OER), PCO2, and pH from the RCP inflow and outflow were used to determine the time course for O2 delivery in 28 adults undergoing aortic reconstruction using HCA with RCP. HCA was instituted after systemic cooling on cardiopulmonary bypass for 3 min after the electroencephalogram became isoelectric. RCP with oxygenated blood at 10 degrees C was administered at an internal jugular venous pressure of 20-25 mm Hg. Serial analyses of blood oxygen, carbon dioxide, pH, and hemoglobin concentration were made in samples from the RCP inflow (superior vena cava) and outflow (innominate and left carotid arteries) at different times after institution of RCP. Nineteen patients had no strokes, five patients had preoperative strokes, and four patients had intraoperative strokes. In the group of patients without strokes, HCA with RCP was initiated at a mean nasopharyngeal temperature of 14.3 degrees C with mean RCP flow rate of 220 mL/min, which lasted 19-70 min. OER increased over time to a maximal detected value of 0.66 and increased to 0.5 of its maximal detected value 15 min after initiation of HCA. The RCP inflow-outflow gradient for PCO2 (slope 0.73 mm Hg/min; P < 0.001) and pH (slope 0.007 U/min; P < 0.001) changed linearly over time after initiation of HCA. In the group of patients with preoperative or intraoperative strokes, the OER and the RCP inflow-outflow gradient for PCO2 changed significantly more slowly over time after HCA compared with the group of patients without strokes. During RCP, continued CO2 production and increased O2 extraction over time across the cerebral vascular bed suggest the presence of viable, but possibly ischemic tissue. Reduced cerebral metabolism in infarcted brain regions may explain the decreased rate of O2 extraction during RCP in patients with strokes.Examining the time course of oxygen extraction, carbon dioxide production, and pH changes from the retrograde cerebral perfusate provided a means to assess metabolic activity during hypothermic circulatory arrest.

  View details for Web of Science ID 000077901200002

  View details for PubMedID 9895058

• Detection of stroke during cardiac operations with somatosensory evoked responses JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Stecker, M. M., Cheung, A. T., Patterson, T., Savino, J. S., Weiss, S. J., Richards, R. M., Bavaria, J. E., Gardner, T. J. 1996; 112 (4): 962-972

  Abstract

  The objectives of this study were to determine if monitoring of intraoperative somatosensory evoked potentials could be used to detect stroke during cardiac operations and to establish indicators of cerebral ischemia based on changes in these potentials.Twenty-five patients undergoing cardiac operations underwent preoperative and postoperative neurologic examinations as well as intraoperative recording of somatosensory evoked potentials. Detailed analysis of the waveforms of these potentials was performed.Two of the 25 patients had intraoperative strokes. These patients and only these patients had changes in their somatosensory evoked potentials during the operation suggesting cerebral ischemia. The unilateral disappearance of the cortical somatosensory evoked potential waves correlated significantly with the clinical outcome of stroke (p < 0.004). Ischemic changes were detected in real time and were related to the removal of the aortic crossclamp in one patient and to the initiation of cardiopulmonary bypass in the other.Somatosensory evoked potentials can detect intraoperative stroke during cardiac operations. Acute, unilateral decreases in amplitude of the cortical potential are more useful than changes in latency in detecting intraoperative stroke.

  View details for Web of Science ID A1996VW27500013

  View details for PubMedID 8873722

• Beat-to-beat augmentation of left ventricular function by intraaortic counterpulsation American-Society-of-Anesthesiologists Annual Meeting Cheung, A. T., Savino, J., Weiss, S. J. LIPPINCOTT-RAVEN PUBL. 1996: 545–54

  Abstract

  Measuring the effects of intraaortic balloon counterpulsation (IABP) in single cardiac beats may permit an improved understanding of the physiologic mechanisms by which IABP improves the circulation. The objective of the study was to use trans- esophageal echocardiography in combination with hemodynamic measurements to test the hypothesis that IABP improves global left ventricular systolic function selectively in the IABP-augmented cardiac beats by acutely decreasing left ventricular afterload.Twenty-seven studies in which the IABP-to-R wave trigger ratio was serially changed from 1:1, 1:2, 1:4, 0:1 (IABP off) and back to 1:1 were performed in 20 anesthetized cardiac surgical patients during IABP support. Left ventricular short-axis end-diastolic cross-sectional area, end-systolic area, mean end-systolic wall thickness, and ejection time were measured by transesophageal echocardiography at the midpapillary muscle level. Aortic pressure was measured simultaneously from the central lumen of the intraaortic balloon catheter. These measurements were used to calculate the fractional area change, end-systolic meridional wall stress, and heart rate-corrected velocity of circumferential fiber shortening. The echocardiographic and hemodynamic parameters of left ventricular preload, afterload, and systolic function immediately after balloon deflation (IABP-augmented cardiac beats) were compared to the parameters measured during nonaugmented cardiac beats to determine the beat-to-beat effects of IABP on left ventricular function.IABP-augmented cardiac beats had a decreased systolic arterial pressure and end-systolic meridional wall stress and increased diastolic blood pressure, fractional area change, and velocity of circumferential fiber shortening compared to nonaugmented cardiac beats. IABP did not cause significant beat-to-beat changes in heart rate, pulmonary artery diastolic pressure, or central venous pressure. The improvement in left ventricular systolic function associated with IABP-augmented cardiac beats correlated with the decrease in end-systolic meridional wall stress for that cardiac beat.Beat-to-beat echocardiographic and hemodynamic measurements performed in anesthetized cardiac surgical patients during IABP support demonstrated improved left ventricular systolic function and decreased left ventricular systolic wall stress in the cardiac beats immediately after balloon deflation. The relationship between left ventricular systolic function and left ventricular systolic wall stress during IABP support suggests that afterload reduction was an important mechanism by which IABP instantaneously improved circulatory function in anesthetized cardiac surgical patients.

  View details for Web of Science ID A1996UA37700010

  View details for PubMedID 8659782

• Fatal paradoxical cerebral embolization during bilateral knee arthroplasty ANESTHESIOLOGY Weiss, S. J., Cheung, A. T., Stecker, M. M., Garino, J. P., Hughes, J. E., Murphy, F. L. 1996; 84 (3): 721-723

  View details for Web of Science ID A1996UA37700029

  View details for PubMedID 8659801

• Calcium blockage in pulmonary hypertension and hypoxic vasoconstriction. New horizons (Baltimore, Md.) NEELY, C. F., Stein, R., Matot, I., Batra, V., Cheung, A. 1996; 4 (1): 99-106

  Abstract

  Both extracellular and intracellular calcium (Ca2+) play important roles in hypoxic pulmonary vasoconstriction (HPV) and the vasoconstrictor responses to endogenous pulmonary vasoconstrictor substances, as evidenced by the effect of calcium-channel blockers on these vasoconstrictor responses and the measurement of changes in Ca2+ flux or intracellular Ca2+ concentrations in isolated cells. The more vasoselective the calcium-channel blocker, the greater its effect on pulmonary vasoconstriction. However, these drugs are not selective for the pulmonary vascular bed and are not as potent as pulmonary vasodilators when compared with other vasodilator drugs, including prostaglandin E1, isoproterenol, prostacyclin, or nitroglycerin. Moreover, the primary effect of vasoselective calcium-channel blockers on pulmonary vascular resistance is secondary to the effects of these agents on systemic vascular resistance and cardiac output. Although there is improvement in oxygen delivery, exercise tolerance, and survival in patients with primary pulmonary hypertension who respond to calcium-channel blockers, the response of individual patients to these drugs is difficult to predict because the extent of reversible versus irreversible changes in the pulmonary vasculature is not known. The use of these drugs in patients with chronic hypoxia-induced pulmonary vasoconstriction may be associated with a worsening of ventilation-perfusion mismatching secondary to inhibition of HPV.

  View details for PubMedID 8689279

• DETECTION OF ACUTE EMBOLIC STROKE DURING MITRAL-VALVE REPLACEMENT USING SOMATOSENSORY-EVOKED POTENTIAL MONITORING ANESTHESIOLOGY Cheung, A. T., Savino, J. S., Weiss, S. J., Patterson, T., Richards, R. M., Gardner, T. J., Stecker, M. M. 1995; 83 (1): 208-210

  View details for Web of Science ID A1995RH99900026

  View details for PubMedID 7605001

• ECHOCARDIOGRAPHIC AND HEMODYNAMIC INDEXES OF LEFT-VENTRICULAR PRELOAD IN PATIENTS WITH NORMAL AND ABNORMAL VENTRICULAR-FUNCTION ANESTHESIOLOGY Cheung, A. T., Savino, J. S., Weiss, S. J., Aukburg, S. J., Berlin, J. A. 1994; 81 (2): 376-387

  Abstract

  Transesophageal echocardiography (TEE) is used to diagnose hypovolemia despite the lack of validation studies. The objective was to determine the effects of acute graded hypovolemia on TEE and conventional hemodynamic determinants of left ventricular (LV) preload in anesthetized patients with normal and abnormal LV function.Determinants of LV preload derived from TEE and hemodynamic monitoring were measured serially in 35 anesthetized cardiac surgical patients without valvular heart disease. Patients were stratified into two groups: those with normal LV function (group 1, n = 17) and those with LV wall motion abnormalities (group 2, n = 13). Patients in groups 1 and 2 were subjected to graded hypovolemia produced by collecting 6 aliquots of blood, each equal to 2.5% of their estimated blood volume (EBV). A third group of patients (group 3, n = 5), not subjected to graded hypovolemia, were studied to test for time-dependent changes.Group 2 had a significantly greater baseline (mean +/- SD) pulmonary artery occlusion pressure (17 +/- 6 vs. 11 +/- 6 mmHg), LV end-diastolic area (23 +/- 5 vs. 18 +/- 4 cm2), LV end-diastolic wall stress (23 +/- 10 vs. 14 +/- 6 x 10(3) dyne.cm-2), and smaller fractional area change (35 +/- 13 vs. 59 +/- 7%). In groups 1 and 2, the LV end-diastolic area, pulmonary artery occlusion pressure, and LV end-diastolic wall stress decreased linearly in response to blood loss in the range of 0-15% of the EBV. No significant changes in the measured parameters occurred in group 3. A significant decrease in the central venous pressure, pulmonary artery occlusion pressure, and LV end-diastolic area was detected in response to a 2.5% EBV deficit (approximately 1.75 ml.kg-1) in groups 1 and 2. The mean change in LV end-diastolic area (0.3 cm2/1.0% EBV deficit) in response to equivalent EBV deficits was the same in groups 1 and 2. In contrast, the mean change in cardiac output and LV end-diastolic wall stress was less in group 2 despite a greater decrease in pulmonary artery occlusion pressure. Compared to group 1, a greater EBV deficit (7.5% to 12.5% vs. 2.5% to 5%) was required in group 2 to cause a significant decrease in the cardiac output, stroke volume, mixed venous oxygen saturation, and LV end-diastolic wall stress.TEE and hemodynamic determinants of LV preload detected changes in LV function caused by acute blood loss. Acute blood loss caused directional changes in LV end-diastolic area, pulmonary artery occlusion pressure, and LV end-diastolic wall stress even in patients with LV wall motion abnormalities. Changes in LV end-diastolic wall stress, derived from both TEE and hemodynamic measurements corresponded to changes in cardiac output, stroke volume, and mixed venous oxygen saturation that occurred during acute blood loss.

  View details for Web of Science ID A1994PA47900014

  View details for PubMedID 8053588

• Oropharyngeal injury after transesophageal echocardiography. Journal of cardiothoracic and vascular anesthesia Savino, J. S., Hanson, C. W., Bigelow, D. C., Cheung, A. T., Weiss, S. J. 1994; 8 (1): 76-78

  View details for PubMedID 8167291