Clinical Focus

  • Cardiac Catheterization
  • Echocardiography
  • Interventional Cardiology

Professional Education

  • Board Certification: Royal College of Physicians and Surgeons of Canada, Pediatrics (1994)
  • Board Certification: Royal College of Physicians and Surgeons of Canada, Pediatric Cardiology (1997)
  • Fellowship: Hospital for Sick Children Pediatric Cardiology (1997) Canada
  • Residency: Hospital For Sick Children (1994) Canada
  • Internship: University of Toronto (1990) Canada
  • Medical Education: University of Toronto MD Program (1989) Canada

All Publications

  • Current-era outcomes of balloon aortic valvotomy in neonates and infants JACC: Advances Christensen, A. H., Chaturvedi, R. R., Callahan, C. P., Lee, K., Wan, A., Barron, D. J., Honjo, O., Benson, L. N. 2022
  • Thoracic epidural anesthesia in congenital heart surgery JTCVS Techniques Schmehil, C., Lee, K., Casella, S., Millan, D. 2022; 11: 64-66
  • Is there a role for endovascular stent implantation in the management of postoperative right ventricular outflow tract obstruction in the era of transcatheter valve implantation? CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS Kang, S., Ramroop, R., Manojlovich, L., Runeckles, K., Fan, S., Chaturvedi, R. R., Lee, K., Benson, L. N. 2021


    The optimal management pathway for the dysfunctional right ventricular outflow tract (RVOT) is uncertain. We evaluated the long-term outcomes and clinical impact of stent implantation for obstructed RVOTs in an era of rapidly progressing transcatheter pulmonary valve technology.Retrospective review of 151 children with a biventricular repair who underwent stenting of obstructed RVOT between 1991 and 2017.RVOT stenting resulted in significant changes in peak right ventricle (RV)-to-pulmonary artery (PA) gradient (39.4 ± 17.1-14.9 ± 8.3; p < 0.001) and RV-to-aortic pressure ratio (0.78 ± 0.22-0.49 ± 0.13; p < 0.001). Subsequent percutaneous reinterventions in 51 children to palliate recurrent stenosis were similarly effective. Ninety-nine (66%) children reached the primary outcome of subsequent pulmonary valve replacement (PVR). Freedom from PVR from the time of stent implantation was 91%, 51%, and 23% at 1, 5, and 10 years, respectively. Small balloon diameters for stent deployment were associated with shorter freedom from PVR. When additional children without stent palliation (with RV-to-PA conduits) were added to the stent cohort (total 506 children), the multistate analysis showed the longest freedom from PVR in those with stent palliation and subsequent catheter reintervention. Pulmonary regurgitation was well-tolerated clinically. Indexed RV dimensions and function estimated by echocardiography remained stable at last follow up or before primary outcome.Prolongation of conduit longevity with stent implant remains an important strategy to allow for somatic growth to optimize the risk-benefit profile for subsequent surgical or transcatheter pulmonary valve replacement performed at an older age.

    View details for DOI 10.1002/ccd.30043

    View details for Web of Science ID 000735913600001

    View details for PubMedID 34967102

  • The COAST Is Not Clear: Late Aneurysms and Fractures. Circulation. Cardiovascular interventions Adamson, G. T., Lee, K. J. 2021: CIRCINTERVENTIONS121010886
  • Balloon Angioplasty for Native Aortic Coarctation in 3- to 12-Month-Old Infants. Circulation. Cardiovascular interventions Sandoval, J. P., Kang, S. L., Lee, K. J., Benson, L., Asoh, K., Chaturvedi, R. R. 2020; 13 (11): e008938


    Balloon angioplasty for native coarctation of the aorta (CoA) is successful in children and adults but in neonates results in frequent restenosis. The efficacy of balloon angioplasty for native CoA during infancy beyond the neonatal period was examined in infants aged 3 to 12 months of age.A retrospective review of 68 infants who underwent balloon angioplasty for native CoA. 95% CI are in parentheses.Procedural age was (mean±SD) 6±3.4 months and weight was 7±1.8 kg. Balloon angioplasty produced a large decrease in both the noninvasive arm-to-leg blood pressure gradient (41.2±18.7 to 5.6±9.6 mm Hg) and the invasive peak systolic pressure gradient (34±12 to 11±9 mm Hg). Balloon angioplasty increased the CoA diameter from 2.7±1 mm to 4.6±1.2 mm. One patient was lost to follow-up. A catheter reintervention was required in 11.8% and surgery in 10.3%. The hazard of reintervention was highest early. Median freedom from reintervention was 89% (95% CI, 80%-96%) at 1 year, 83% (95% CI, 73%-92%) at 5 years, and 81% (95% CI, 69%-90%) at 10 years. Femoral artery thrombosis was documented in 6 (9%) infants without any long-term consequence. One patient developed a small aortic aneurysm late and has not required treatment. A robust estimate of the frequency of aortic aneurysms remains to be determined as the majority of subjects have not had cross-sectional imaging.Balloon angioplasty of native CoA is effective and safe in infants aged 3 to 12 months with outcomes comparable to those in older children and adults. Catheter reinterventions can avoid the need for surgery in most patients.

    View details for DOI 10.1161/CIRCINTERVENTIONS.120.008938

    View details for PubMedID 33167702

  • Using the arterial cannula for cardiac catheterization in neonates and small infants supported by extracorporeal membrane oxygenation. The Journal of thoracic and cardiovascular surgery Kang, S. L., Lee, K. J., Stanisic, A., Chaturvedi, R. R. 2019

    View details for DOI 10.1016/j.jtcvs.2019.03.119

    View details for PubMedID 31126658

  • Automated 3-Dimensional Single-Beat Real-Time Volume Colour Flow Doppler Echocardiography in Children: A Validation Study of Right and Left Heart Flows. The Canadian journal of cardiology Kato, A., Sandoval, J. P., Mroczek, D., Chaturvedi, R., Houle, H., Georgescu, B., Yoo, S. J., Benson, L. N., Lee, K. J. 2018; 34 (6): 726-735


    Novel quantification of stroke volume according to mitral inflow and aortic outflow using automated real-time 3-dimensional volume colour flow Doppler echocardiography (3D-RT-VCFDE) is more accurate than 2-dimensional echocardiography and has excellent correlation with cardiac magnetic resonance imaging-based flows in adults. This technology is applied for the first time to the right heart and in children.3D-RT-VCFDE was performed in 61 image sets of flow through the aortic (AV), mitral (MV), pulmonary (PV), and tricuspid (TV) valves of 34 children. These were compared with stroke volumes of the right (RV) and left (LV) ventricles and ratio of pulmonary to systemic blood flow determined using the Fick method in 31 children with atrial shunts.The mean age was 8.0 ± 3.3 years, and the mean weight was 27.8 ± 10.0 kg. The mean temporal resolution for flow analyses was ≥ 22 volumes per second. In conditions with no shunt, the correlations were: AV with MV flows (r = 0.98), PV with TV flows (r = 0.96), RV stroke volume with PV flow (r = 0.95), and with TV flow (r = 0.93), LV stroke volume with AV flow (r = 0.87), and with MV flow (r = 0.89). Fick ratio of pulmonary to systemic blood flow correlations were: PV/AV ratio (r = 0.84), TV/MV ratio (r = 0.87), and RV/LV ratio (r = 0.70).Stroke volume determined using automated 3D-RT-VCFDE is feasible in children and in the right side of the heart. This technique potentially provides a noninvasive alternative to historically invasively acquired hemodynamic data and to cardiac magnetic resonance imaging.

    View details for DOI 10.1016/j.cjca.2018.03.001

    View details for PubMedID 29801738

  • Outcomes of Blalock-Taussig shunts in current era: A single center experience. Congenital heart disease Sasikumar, N., Hermuzi, A., Fan, C. S., Lee, K. J., Chaturvedi, R., Hickey, E., Honjo, O., Van Arsdell, G. S., Caldarone, C. A., Agarwal, A., Benson, L. 2017; 12 (6): 808-814


    Mortality associated with the modified Blalock-Taussig shunt (MBTS) remains high despite advanced perioperative management. This study was formulated to provide data on (1) current indications, (2) outcomes, and (3) factors affecting mortality and morbidity.A retrospective single center chart review identified 95 children (excluding hypoplastic left heart lesions) requiring a MBTS. Mortality and major morbidity were analyzed using the Kaplan Meier method and risk factor analysis using Cox's proportional hazard regression.Median age was 8 (0-126) days, weight 3.1(1.7-5.4) kg. Seventy-three percent were neonates, 58% duct dependent and 73% had single ventricle physiology. Ninety-seven percent had a sternotomy approach for shunt placement with 70% receiving a 3.5 mm graft. Mean graft index (shunt cross sectional area [mm2 ]/BSA [m2 ]) was 44.39 ± 8.04 and shunt size (mm) to body weight (kg) ratio 1.1 ± 0.2. Hospital mortality was 12%, with an interval mortality of 6%. Shunt thrombosis/stenosis occurred in 23% and pulmonary over circulation in 30%, while shunt reoperation was required in 12% and catheter intervention in 8% of the cohort. At 1-year, survival was 82.0% (95% CI [72.7%, 88.4%]), and survival free of major morbidity 61.4% (95% CI [50.7%, 70.5%]). Duct dependency predisposed to mortality (P = .01, HR 6.74 [1.54, 29.53]) and composite outcome (mortality and major morbidity) (P = .04, HR 2.15, CI [1.036, 4.466]) and higher graft index to mortality (P = .005, HR 1.07 [1.02, 1.12]).The commonest indication for a MBTS in the current era was single ventricle palliation. Morbidity and mortality was considerable, partly explained by the higher at risk population. Alternative methods to maintain pulmonary blood flow in place of a MBTS requires further investigation.

    View details for DOI 10.1111/chd.12516

    View details for PubMedID 28736841

  • Clinical Impact of Stent Implantation for Coarctation of the Aorta with Associated Hypoplasia of the Transverse Aortic Arch. Pediatric cardiology Lu, W. H., Fan, C. S., Chaturvedi, R., Lee, K. J., Manlhiot, C., Benson, L. 2017; 38 (5): 1016-1023


    The aim of this study was to explore the clinical impact of transverse aortic arch hypoplasia (TAH) after stent implementation for isthmal coarctation of the aorta (CoA). From a retrospective chart review, 51 children (median age 11.1 years) were identified who had TAH and a CoA stent implanted between 10/1995 and 4/2015. Arm-leg cuff blood pressure measurements, echocardiographic arch imaging, and 24-h ambulatory blood pressure monitoring, prior to and after stent implantation, were reviewed. At catheterization, peak systolic gradients across the CoA's were 25 mmHg before and 4 mmHg after stent implantation. At a median 37-month follow-up, echocardiographic imaging showed no significant catch-up growth in the transverse arch (median z-score; proximal and distal arch -1.54 and -1.99 vs. -1.78 and -1.63, p = 0.13 and 0.90). A trend to increasing systolic blood pressure (SBP) differentials between the right and left arms was noted (11 mmHg [prior to]; 16 mmHg [follow-up], p = 0.09). Age-adjusted percentiles for right arm SBP decreased from 99.7% prior to, and 87.6% in follow-up (p < 0.001). The median time to re-intervention was 5.6 years (95% CI [2.8, 7.8]) and the proportion of children using anti-hypertensive in follow-up was not significantly different before the implantation (38% [prior to]; 45% [follow-up]). Elevated right arm blood pressure persists after successful stent implantation in the setting of associated TAH and there appears to be no catch-up growth of the transverse arch with time. Medical management can be difficult and approaches to surgical arch augmentation or stent implantation should be considered to avoid unilateral arm hypertension.

    View details for DOI 10.1007/s00246-017-1611-z

    View details for PubMedID 28396934

  • Impacts of early cardiac catheterization for children with congenital heart disease supported by extracorporeal membrane oxygenation. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Kato, A., Lo Rito, M., Lee, K. J., Haller, C., Guerguerian, A. M., Sivarajan, V. B., Honjo, O. 2017; 89 (5): 898-905


    Cardiac catheterization is often required for patients on extracorporeal membranous oxygenation (ECMO) support, though its efficacy remains unclear. This study aimed to assess the impact of catheterization on successful ECMO weaning.This is a single-center retrospective study from 2000 to 2014. Patients with congenital heart disease who underwent cardiac catheterization while on cardiac ECMO support were included. Logistic regression analysis and Kaplan-Meier survival analysis with log-rank test were performed to determine predictors for successful weaning and patient outcome.Forty-nine catheterizations in 47 patients with the median age of 65 days (range: 1 day-12 years) and the median body weight of 4.2 kg (range: 1.9-32.7 kg) were included. Median duration between ECMO cannulation and catheterization was 1 day (range: 0-11 days). Thirty-three patients (70%) succeeded in decannulation and 24 patients (51%) survived to hospital discharge. Absence of renal (P = 0.045) and respiratory complications (P = 0.031) were significant prognostic factors for successful weaning in multivariate analysis. Patients who received catheterization within 48 hr after ECMO cannulation demonstrated less respiratory complications (P = 0.006) and better survival at 30 days after ECMO initiation (P = 0.039) than those who underwent later catheterization. There was no mortality; however, nine major catheterization-related complications (18%) were detected.Catheterization for pediatric patients on ECMO support can be performed, although this group contained high risk of serious adverse events. The absence of ECMO complications is a predictor for successful weaning. An earlier catheterization appears to be associated with better short-term survival in this cohort. © 2016 Wiley Periodicals, Inc.

    View details for DOI 10.1002/ccd.26632

    View details for PubMedID 27416545

  • Right Ventricular Outflow Tract Stenting in Tetralogy of Fallot Infants With Risk Factors for Early Primary Repair. Circulation. Cardiovascular interventions Sandoval, J. P., Chaturvedi, R. R., Benson, L., Morgan, G., Van Arsdell, G., Honjo, O., Caldarone, C., Lee, K. J. 2016; 9 (12)


    Tetralogy of Fallot with cyanosis requiring surgical repair in early infancy reflects poor anatomy and is associated with more clinical instability and longer hospitalization than those who can be electively repaired later. We bridged symptomatic infants with risk factors for early primary repair by right ventricular outflow tract stenting (stent).Four groups of tetralogy of Fallot with confluent central pulmonary arteries were studied: stent group (n=42), primary repair (aged <3 months) with pulmonary stenosis (early-PS group; n=44), primary repair (aged <3 months) with pulmonary atresia (early-PA group; n=49), and primary repair between 3 and 11 months of age (surg>3mo group; n=45). Stent patients had the smallest pulmonary arteries with a median (95% credible intervals) Nakata index (mm2/m2) of 79 (66-85) compared with the early-PA 139 (129-154), early-PS 136 (121-153), and surg>3mo 167 (153-200) groups. Only stent infants required unifocalization of aortopulmonary collaterals (17%). Stent and early-PA infants had younger age and lower weight than early-PS infants. Stent infants had the most multiple comorbidities. Stenting allowed deferral of complete surgical repair to an age (6 months), weight (6.3 [5.8-7.0] kg), and Nakata index (147 [132-165]) similar to the low-risk surg>3mo group. The 3 early treatment groups had similar intensive care unit/hospital stays and high reintervention rates in the first 12 months after repair, compared with the surg>3mo group.Right ventricular outflow tract stenting of symptomatic tetralogy of Fallot with poor anatomy (small pulmonary arteries) and adverse factors (multiple comorbidities, low weight) relieves cyanosis and defers surgical repair. This allowed pulmonary arterial and somatic growth with clinical results comparable to early surgical repair in more favorable patients.

    View details for DOI 10.1161/CIRCINTERVENTIONS.116.003979

    View details for PubMedID 27965298

  • Achievable radiation reduction during pediatric cardiac catheterization: How low can we go? Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Borik, S., Devadas, S., Mroczek, D., Lee, K. J., Chaturvedi, R., Benson, L. N. 2015; 86 (5): 841-8


    To assess the effectiveness of radiation-reduction measures implemented during pediatric catheterization, and provide data on the radiation doses for common interventional and diagnostic procedures, indexed to body weight.Ionizing radiation exposure must be minimized to "as low as reasonably achievable," by instituting radiation-limiting techniques and knowledge of expected radiation exposure.Radiation-reduction measures included pulsed-fluoroscopy at 7.5 pulses/second (0.032-0.045 µGy/pulse), an air-gap magnification technique for children<20 kg, operator awareness, and additional exposure reduction techniques through projection optimization. Radiation doses for procedures performed between 2007 through 2014 were retrospectively reviewed, including dose area product (DAP) and DAP/kg of body weight for 25 procedural types. Median doses were compared with those previously published from other large centers and multi-institutional databases and assessed for changes over time.Reviewed were 5,196 cases, which included 2,819 interventional, 710 endomyocardial biopsies and 1,667 diagnostic studies, documenting a significant difference in exposure between various procedures and body weights. The absolute exposure was significantly greater in larger children (e.g., for ductal closure median DAP/kg: 17 µGy*m2/kg 10-20 kg children vs. 37 µGy*m2 /kg for those>30 kg, P<0.001). Dose exposure using radiation-reduction techniques were the lowest reported in the literature for all procedure types compared (e.g. median DAP for pulmonary valvuloplasty 163 µGy*m2 vs. 405 to 1,230 µGy*m2 reported by 3 large centers). Reduction of fluoroscopy acquisition to 7.5 pulses/second nearly halved radiation exposure (P<0.001).Implementing a radiation dose reduction and awareness program can lead to documented reduction in exposure, across a variety of procedures performed by multiple operators.

    View details for DOI 10.1002/ccd.26024

    View details for PubMedID 26011560

  • Three-dimensional rotational angiography in the assessment of vascular and airway compression in children after a cavopulmonary anastomosis. Pediatric cardiology Borik, S., Volodina, S., Chaturvedi, R., Lee, K. J., Benson, L. N. 2015; 36 (5): 1083-9


    The aim of the study was to examine the role of three-dimensional rotational angiography (3DRA) in assessing vascular and airway narrowing in children with a bidirectional cavopulmonary anastomosis (BCPA). The course of children with single ventricle physiology is often complicated by left pulmonary artery (LPA) and/or bronchial stenosis and may be related to aortic compression. 3DRA may be useful in evaluating this complex anatomy and possible mechanisms for the observed obstruction. Clinical data and imaging (2D angiography and 3DRA) of children with a BCPA were reviewed retrospectively. Measurements were taken at similar locations along the pulmonary arteries in both modalities and in the airways on 3DRA. Twenty-five children with a previous BCPA were assessed at mean age of 3.1 ± 2.0 years and weight of 13.6 ± 3.6 kg. Excellent correlation was found between 3DRA and 2D angiographic LPA measurements (r = 0.89, p < 0.0001). Twelve children had qualitative LPA stenosis on 3DRA, with a stenotic dimension of 6.6 ± 2.2 mm on 2D angiography and 6.8 ± 1.9 mm on 3DRA (r = 0.94, p < 0.0001). Ten cases with LPA stenosis also had bronchial stenosis (83 %). Qualitative airway assessment correlated with quantitative bronchial dimensions from 3DRA-derived tomographic images: Bronchial stenosis measured 4.4 ± 1.6 versus 5.9 ± 1.1 mm in those with a normal appearing bronchus (p = 0.009). Hybrid patients (initial palliation with bilateral pulmonary artery banding and arterial ductal stenting, n = 5) and all patients with a Damus-Kaye-Stansel (DKS) anastomosis (n = 9) were more likely to have LPA and left bronchial stenosis (OR 7.7, p = 0.04). 3DRA is a useful and accurate tool in assessment of LPA and airway narrowing after BCPA. Hybrid and DKS patients are more prone to LPA and bronchial stenosis, and 3DRA can provide insight into the mechanism.

    View details for DOI 10.1007/s00246-015-1130-8

    View details for PubMedID 25762468

  • Pharmacokinetics of sirolimus-eluting stents implanted in the neonatal arterial duct. Circulation. Cardiovascular interventions Lee, K. J., Seto, W., Benson, L., Chaturvedi, R. R. 2015; 8 (5)


    Sirolimus-eluting stents may have clinical advantages over bare-metal stents in the extremely proliferative environment of the neonatal arterial duct. However, sirolimus has immunosuppressive actions and little is known regarding sirolimus pharmacokinetics in the newborn.This is a retrospective review of sirolimus pharmacokinetics in neonates who underwent sirolimus-eluting stent implantation in the arterial duct for pulmonary blood flow augmentation. Pharmacokinetic parameters were obtained by noncompartmental analysis and by a Bayesian one-compartment nonlinear mixed model. Nine neonates received a single sirolimus-eluting stent with a total sirolimus dose of 245 μg (n = 1), 194 μg (n = 5), or 143 μg (n = 3). Peak sirolimus concentrations were 13.6 ± 4.5 μg/L (24.8 μg/L highest) and clearance was 0.042 ± 0.03 L/hour (noncompartmental analysis) and 0.051 L/hour (95% credible intervals 0.037-0.069, nonlinear mixed model). Sirolimus remained > 5 μg/L, the trough level used in oral immunosuppressive therapy, for (95% credible interval) 15.9 (11.4, 22.8), 12.9 (7.6, 19.0), and 8.4 (2.3, 14.5) days for the 245, 194, and 143 μg sirolimus dose stents, respectively. Estimates of the duration of systemic immunosuppression are provided for combinations of 2 stents.In neonates after sirolimus-eluting stent implantation, peak sirolimus levels were 20 × higher and clearance 30 × lower than previously reported in older children and adults. Sirolimus levels were within the immunosuppressive range for a prolonged period, but with no observable clinically significant adverse outcomes.

    View details for DOI 10.1161/CIRCINTERVENTIONS.114.002233

    View details for PubMedID 25940522

  • Pulmonary artery stenosis in hybrid single-ventricle palliation: High incidence of left pulmonary artery intervention. The Journal of thoracic and cardiovascular surgery Rahkonen, O., Chaturvedi, R. R., Benson, L., Honjo, O., Caldarone, C. A., Lee, K. J. 2015; 149 (4): 1102-10.e2


    Pulmonary artery growth is an important determinant of outcome in single-ventricle strategies. Higher rates of pulmonary artery intervention have been reported with hybrid-based palliation when compared with Norwood palliation.We performed a retrospective review of pulmonary artery growth and clinical outcomes in patients undergoing hybrid-based single-ventricle palliation.The stage I hybrid procedure was performed in 72 patients between 2004 and 2012, of whom 54 were on a Fontan palliative pathway. Thirty-four infants completed stage II, and 20 infants underwent the Fontan operation. The mean diameters of the right pulmonary artery (5.6 ± 1.9 mm) and left pulmonary artery (5.6 ± 2.1 mm) were similar before stage II. After stage II, the right and left pulmonary artery diameters were 8.5 ± 2.1 mm and 5.8 ± 1.3 mm, respectively (P < .001), and after the Fontan operation, these were 8.8 ± 2.0 mm and 6.4 ± 1.1 mm, respectively (P = .002). The mean right pulmonary artery z score was normal throughout, but the left pulmonary artery did not maintain a normal size. The cumulative pulmonary artery intervention rate was 50% at any time after stage II. Fifteen interventions (88%) were performed after stage II (35% during the same hospitalization, 71% <60 days). The most intervened site was the midsection of the left pulmonary artery (41%). Initial pulmonary artery intervention was balloon dilation in 59% of patients and stent implantation in 41% of patients. Half of patients with initial balloon dilation required reintervention.There is significant risk of left pulmonary artery compromise after the second stage of hybrid palliation associated with a high intervention rate.

    View details for DOI 10.1016/j.jtcvs.2014.11.080

    View details for PubMedID 25595374

  • Characteristics of secundum atrial septal defects not percutaneously closed. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Ohno, N., Chaturvedi, R., Lee, K. J., Benson, L. 2015; 85 (2): 234-9


    We sought to review our single center experience with secundum atrial septal defect (ASD) device closure, evaluating the incidence and morphological characteristics where percutaneous closure was thought inappropriate.All children assessed as unsuitable for transcatheter device closure were reviewed. Data collected included: demographics, defect morphology by echocardiography or at cardiac catheterization and defect size focusing on the reasons for procedural deferral.Between January 2002 and December 2010, 639 children underwent closure of an isolated secundum ASD: 82 children (13%) where referred directly to surgery, 43 (6%) were thought unsuitable for device closure at the time of catheterization and underwent subsequent surgery and the remaining 514 (81%) underwent successful device closure including 2 on a second attempt. The reasons for pursuing a surgical closure (n = 124, mean age = 5.7 years; range: 0.6-17.4 years; defect diameter/body weight = 1.39) included: the need for a device thought too large for implantation versus the child's size (n = 51), defects with deficient rim(s) (n = 48), multiple defects (n = 7), defects sized >36 mm (n = 2), malposition (n = 2), ECG changes (n = 3), aneurysmal IAS (n = 2), sinus venosus (n = 2), or others (n = 7).The reasons for deferring transcatheter device closure of a secundum ASD are diverse, not only isolated rim deficiencies but the requirements of large implants, malposition, arrhythmias, and lack of hemodynamic need are influential components in clinical decision making.

    View details for DOI 10.1002/ccd.25700

    View details for PubMedID 25315692

  • Percutaneous pulmonary valve implantation: 5 years of follow-up: does age influence outcomes? Circulation. Cardiovascular interventions Borik, S., Crean, A., Horlick, E., Osten, M., Lee, K. J., Chaturvedi, R., Friedberg, M. K., McCrindle, B. W., Manlhiot, C., Benson, L. 2015; 8 (2): e001745


    Percutaneous pulmonary valve implantation (PPVI) is a safe, less invasive alternative to surgical valve replacement for the congenital heart disease patient with right ventricular (RV) outflow tract dysfunction. The aim of this study was to determine whether reverse RV remodeling after PPVI was persistent in the longer term and whether timing of PPVI influenced outcomes.Consecutive patients from the pediatric and adult congenital heart disease programs were enrolled. Cardiac MRI, echocardiography, metabolic exercise testing, chest radiography, and hemodynamics before intervention were compared with repeated follow-up measurements to assess changes over time. Fifty-one patients (including 23 patients <16 years old) were followed for a mean 4.5±1.9 (0.9-6.9) years after implantation, 59% of patients having available comparative cardiac MRI data. Freedom from any reintervention was 87% and 68% at 3 and 5 years, and freedom from surgery was 90% at 5 years. For every decade younger at implantation, there was an increase of 3.9%±1.0% in cardiac MRI left ventricular ejection fraction (P<0.001) and 2.4±0.9 mL/kg/min in maxVO2 (P=0.005) and a decrease of 0.7±0.2 cm in RV end-diastolic dimension (P<0.001) after intervention. Younger patients displayed an additional decline in the RV/left ventricular end-diastolic volume ratio (P=0.05) and trended toward improved RV ejection fraction in late follow-up (50%±7% versus 41%±12%, P=0.07).This is the largest series to show that PPVI at a younger age yields incremental improvements in RV size and maximum oxygen consumption. Early valve implantation is associated with better RV function and should be considered in management planning for this population.

    View details for DOI 10.1161/CIRCINTERVENTIONS.114.001745

    View details for PubMedID 25652317

  • The First Ten of Everything: A Review of Past and Current Practice in Pediatric Cardiac Percutaneous Interventions. Congenital heart disease Rahkonen, O. P., Lee, K. J., Chaturvedi, R. C., Benson, L. N. 2015; 10 (4): 292-301


    This study was designed to compare outcomes of the most common pediatric cardiac interventions from the time of implementation with the current era.Since the introduction of semilunar valve balloon dilation and device closure of the arterial duct and septal defects, development of interventional techniques and devices has been rapid. However, few studies have compared outcomes between those initial interventions and those in the current era.Five validated common catheter-based therapies were chosen for analysis, including atrial and duct device closure, balloon dilation of the aortic and pulmonary valves, and native coarctation of the aorta. A retrospective review of the first and most recent 10 consecutive patients in each group was performed.There was a high mortality (30%) among neonates who underwent aortic valve (AV) dilation in the early era, but no mortality noted in other groups. In the early era, transcatheter atrial defect closure and AV dilations were associated with a low success rate (60% for both lesions) and a high complication rate (40% for atrial septal defect, 30% for AV dilations). Among the last 10 children, the atrial defect occlusion was successful in 100% without complications and AV dilations where successful in all children with a 30% complication rate (one major, two minor).A learning curve with device development plays a significant role in the evolution of transcatheter techniques. These data provide baseline estimates of success and may be used as a template in the future when new techniques are adapted into practice.

    View details for DOI 10.1111/chd.12247

    View details for PubMedID 25597863

  • Acquired von Willebrand syndrome in paediatric patients with congenital heart disease: challenges in the diagnosis and management of this rare condition. Haemophilia : the official journal of the World Federation of Hemophilia Avila, M. L., Lee, K. J., Bouskill, V., Rand, M. L., James, P., Carcao, M. 2015; 21 (1): e89-92

    View details for DOI 10.1111/hae.12567

    View details for PubMedID 25495773

    View details for PubMedCentralID PMC4675139

  • Direct measurement of aortic regurgitation with phase-contrast magnetic resonance is inaccurate: proposal of an alternative method of quantification. Pediatric radiology Iwamoto, Y., Inage, A., Tomlinson, G., Lee, K. J., Grosse-Wortmann, L., Seed, M., Wan, A., Yoo, S. J. 2014; 44 (11): 1358-69


    Phase-contrast magnetic resonance (MR) has been widely used for quantification of aortic regurgitation. However there is significant practice variability regarding where and how the blood flow data are acquired.To compare the accuracy of flow quantification of aortic regurgitation at three levels: the ascending aorta at the level of the right pulmonary artery (level 1), the aortic valve hinge points at end-diastole (level 2) and the aortic valve hinge points at end-systole (level 3).We performed cardiovascular MR in 43 children with aortic regurgitation. By using phase-contrast MR, we measured the systolic forward, diastolic retrograde and net forward flow volume indices at three levels. At each level, the following comparisons were made: (1) systolic forward flow volume index (FFVI) versus left ventricular cardiac index (LVCI) measured by cine ventricular volumetry; (2) retrograde flow volume index (RFVI) versus estimated aortic regurgitation volume index (which equals LVCI minus pulmonary blood flow index [QPI]); (3) net forward flow volume index (NFVI) versus pulmonary blood flow index.The forward flow volume index, retrograde flow volume index and net forward flow volume index measured at each of the three levels were significantly different except for the retrograde flow volume index measured at levels 1 and 3. There were good correlations between the forward flow volume index and the left ventricular cardiac index at all three levels, with measurement at level 2 showing the best correlation. Compared to the forward flow volume indices, the retrograde flow volume index had a lower correlation with the estimated aortic regurgitation volume indices and had widely dispersed data with larger prediction intervals.Large variations in systolic forward, diastolic retrograde and net forward flow volumes were observed at different levels of the aortic valve and ascending aorta. Direct measurement of aortic regurgitation volume and fraction is inaccurate and should be abandoned. Instead, calculation of the aortic regurgitation volume from more reliable data is advised. We recommend subtracting pulmonary blood flow from systolic forward flow measured at the aortic valve hinge points at end-diastole as a more accurate and consistent method for calculating the volume of aortic regurgitation.

    View details for DOI 10.1007/s00247-014-3017-x

    View details for PubMedID 24939669

  • Impact of pre-stage II hemodynamics and pulmonary artery anatomy on 12-month outcomes in the Pediatric Heart Network Single Ventricle Reconstruction trial. The Journal of thoracic and cardiovascular surgery Aiyagari, R., Rhodes, J. F., Shrader, P., Radtke, W. A., Bandisode, V. M., Bergersen, L., Gillespie, M. J., Gray, R. G., Guey, L. T., Hill, K. D., Hirsch, R., Kim, D. W., Lee, K. J., Pelech, A. N., Ringewald, J., Takao, C., Vincent, J. A., Ohye, R. G. 2014; 148 (4): 1467-74


    To compare the interstage cardiac catheterization hemodynamic and angiographic findings between shunt types for the Pediatric Heart Network Single Ventricle Reconstruction trial. The trial, which randomized subjects to a modified Blalock-Taussig shunt (MBTS) or right ventricle-to-pulmonary artery shunt (RVPAS) for the Norwood procedure, demonstrated the RVPAS was associated with a smaller pulmonary artery diameter but superior 12-month transplant-free survival.We analyzed the pre-stage II catheterization data for the trial subjects. The hemodynamic variables and shunt and pulmonary angiographic data were compared between shunt types; their association with 12-month transplant-free survival was also evaluated.Of 549 randomized subjects, 389 underwent pre-stage II catheterization. A smaller size, lower aortic and superior vena cava saturation, and higher ventricular end-diastolic pressure were associated with worse 12-month transplant-free survival. The MBTS group had a lower coronary perfusion pressure (27 vs 32 mm Hg; P<.001) and greater pulmonary blood flow/systemic blood flow ratio (1.1 vs 1.0, P=.009). A greater pulmonary blood flow/systemic blood flow ratio increased the risk of death or transplantation only in the RVPAS group (P=.01). The MBTS group had fewer shunt (14% vs 28%, P=.004) and severe left pulmonary artery (0.7% vs 9.2%, P=.003) stenoses, larger mid-main branch pulmonary artery diameters, and greater Nakata indexes (164 vs 134, P<.001).Compared with the RVPAS subjects, the MBTS subjects had more hemodynamic abnormalities related to shunt physiology, and the RVPAS subjects had more shunt or pulmonary obstruction of a severe degree and inferior pulmonary artery growth at pre-stage II catheterization. A lower body surface area, greater ventricular end-diastolic pressure, and lower superior vena cava saturation were associated with worse 12-month transplant-free survival.

    View details for DOI 10.1016/j.jtcvs.2013.10.057

    View details for PubMedID 24332668

    View details for PubMedCentralID PMC4053497

  • Changes in systemic and pulmonary blood flow distribution in normal adult volunteers in response to posture and exercise: a phase contrast magnetic resonance imaging study. The journal of physiological sciences : JPS Wong, D. T., Lee, K. J., Yoo, S. J., Tomlinson, G., Grosse-Wortmann, L. 2014; 64 (2): 105-12


    Hemodynamics are usually evaluated in the supine position at rest. This is only a snapshot of an individual's daily activities. This study describes circulatory adaptation, as assessed by magnetic resonance imaging, to changes in position and exercise. Phase contrast magnetic resonance imaging of blood flow within systemic and pulmonary arteries and veins was performed in 24 healthy volunteers at rest in the prone and supine position and with bicycle exercise in the supine position. No change was seen in systemic blood flow when moving from prone to supine. Exercise resulted in an increased percentage of cardiac output towards the lower body. Changes in position resulted in a redistribution of blood flow within the left lung--supine positioning resulted in decreased blood flow to the left lower pulmonary vein. With exercise, both the right and left lower lobes received increased blood flow, while the upper lobes received less.

    View details for DOI 10.1007/s12576-013-0298-z

    View details for PubMedID 24385190

  • Infolding of covered stents used for aortic coarctation: report of two cases. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Wan, A. W., Lee, K. J., Benson, L. N. 2014; 83 (1): 104-8


    Covered stents have been used for the treatment of aortic coarctation to protect the arterial wall during dilation. Early results have shown them to be safe and effective. We report two cases of infolding of the proximal edge of a covered aortic coarctation stent. Management required implantation of a second stent. Poor stent apposition to the vessel wall and/or recoil may allow conditions for these events to occur.

    View details for DOI 10.1002/ccd.24998

    View details for PubMedID 23703810

  • Surgical palliation strategy does not affect interstage ventricular dysfunction or atrioventricular valve regurgitation in children with hypoplastic left heart syndrome and variants. Circulation Chetan, D., Kotani, Y., Jacques, F., Poynter, J. A., Benson, L. N., Lee, K. J., Chaturvedi, R. R., Friedberg, M. K., Van Arsdell, G. S., Caldarone, C. A., Honjo, O. 2013; 128 (11 Suppl 1): S205-12


    All 3 palliation strategies, Norwood, Sano, and Hybrid, currently used for hypoplastic left heart syndrome pose a risk of myocardial injury at different times and through different mechanisms. We sought to compare these strategies to understand longitudinal differences in interstage ventricular dysfunction and their subsequent impact on transplant-free survival and atrioventricular valve regurgitation (AVVR) as well as the relationship between adverse events and ventricular function.Serial echocardiographic reports and clinical data were reviewed for 138 children with hypoplastic left heart syndrome who underwent stage I surgical palliation (Sano: 11; Norwood: 73; Hybrid: 54) between 2004 and 2011. Stage II palliation was achieved in 92 (67%) patients (Sano: 7; Norwood: 51; Hybrid: 34). Interstage transplant-free survival, ventricular dysfunction, and AVVR were equivalent among palliation strategies. Patients with preserved ventricular function had a higher rate of transplant-free survival and freedom from AVVR, regardless of palliation strategy. Patients who had cardiac arrest, cardiopulmonary resuscitation, or extracorporeal membrane oxygenation (adverse events) experienced more transient and persistent ventricular dysfunction compared to those without adverse events. Surgical palliation strategies were not identified as risk factors for ventricular dysfunction or AVVR.Surgical palliation strategy does not affect mortality, interstage ventricular function, or interstage AVVR in children with hypoplastic left heart syndrome. Therefore, the different timing and mechanisms of myocardial injury among palliation strategies do not affect outcomes. Ventricular dysfunction adversely affects transplant-free survival and atrioventricular valve function. Adverse events are associated with the development of ventricular dysfunction. To improve outcomes, interstage treatment should focus on the preservation of ventricular function.

    View details for DOI 10.1161/CIRCULATIONAHA.112.000380

    View details for PubMedID 24030408

  • Intervention for recoarctation in the single ventricle reconstruction trial: incidence, risk, and outcomes. Circulation Hill, K. D., Rhodes, J. F., Aiyagari, R., Baker, G. H., Bergersen, L., Chai, P. J., Fleming, G. A., Fudge, J. C., Gillespie, M. J., Gray, R. G., Hirsch, R., Lee, K. J., Li, J. S., Ohye, R. G., Oster, M. E., Pasquali, S. K., Pelech, A. N., Radtke, W. A., Takao, C. M., Vincent, J. A., Hornik, C. P. 2013; 128 (9): 954-61


    Recoarctation after the Norwood procedure increases risk for mortality. The Single Ventricle Reconstruction (SVR) trial randomized subjects with a single right ventricle undergoing a Norwood procedure to a modified Blalock-Taussig shunt or a right ventricle-pulmonary artery shunt. We sought to determine the incidence of recoarctation, risk factors, and outcomes in the SVR trial.Recoarctation was defined by intervention, either catheter based or surgical. Univariate analysis and multivariable Cox proportional hazard models were performed with adjustment for center. Of the 549 SVR subjects, 97 (18%) underwent 131 interventions (92 balloon aortoplasty, 39 surgical) for recoarctation at a median age of 4.9 months (range, 1.1-10.5 months). Intervention typically occurred at pre-stage II catheterization (n=71, 54%) or at stage II surgery (n=38, 29%). In multivariable analysis, recoarctation was associated with the shunt type in place at the end of the Norwood procedure (hazard ratio, 2.0 for right ventricle-pulmonary artery shunt versus modified Blalock-Taussig shunt; P=0.02), and Norwood discharge peak echo-Doppler arch gradient (hazard ratio, 1.07 per 1 mm Hg; P<0.01). Subjects with recoarctation demonstrated comorbidities at pre-stage II evaluation, including higher pulmonary arterial pressures (15.4±3.0 versus 14.5±3.5 mm Hg; P=0.05), higher pulmonary vascular resistance (2.6±1.6 versus 2.0±1.0 Wood units·m(2); P=0.04), and increased echocardiographic volumes (end-diastolic volume, 126±39 versus 112±33 mL/BSA(1.3), where BSA is body surface area; P=0.02). There was no difference in 12-month postrandomization transplantation-free survival between those with and without recoarctation (P=0.14).Recoarctation is common after Norwood and contributes to pre-stage II comorbidities. Although with intervention there is no associated increase in 1-year transplantation/mortality, further evaluation is warranted to evaluate the effects of associated morbidities.

    View details for DOI 10.1161/CIRCULATIONAHA.112.000488

    View details for PubMedID 23864006

    View details for PubMedCentralID PMC3825266

  • "Reverse Blalock-Taussig shunt": application in single ventricle hybrid palliation. The Journal of thoracic and cardiovascular surgery Baba, K., Honjo, O., Chaturvedi, R., Lee, K. J., Van Arsdell, G., Caldarone, C. A., Benson, L. N. 2013; 146 (2): 352-7


    Retrograde aortic arch malperfusion after ductal stenting can be life-threatening after univentricular hybrid palliation. Arch perfusion can be maintained with a main pulmonary artery to innominate artery shunt placed during the stage I procedure: a "reverse Blalock-Taussig shunt."A retrospective review of 37 infants who underwent hybrid palliation from January 2004 to March 2010 was performed. The infants were divided into 2 groups, those with (group I, n = 16) and those without (group II, n = 21) a reverse Blalock-Taussig shunt.At the initial palliation, no differences were found in the demographics, systolic or diastolic pressures, or ventricular or atrioventricular valve function between the 2 groups. Group I had more infants with aortic atresia (P < .01) and smaller ascending aortas (P < .01). Before stage II, the retrograde aortic Doppler flow velocity increased in group I (P < .01) and was unchanged in group II. The reintervention rates before stage II were similar between the 2 groups. Before stage II, the ventricular end-diastolic pressure, left and right pulmonary artery pressures and diameters, and mixed venous and arterial saturations were similar between the 2 groups. The complication rates between the 2 groups were not significantly different, although a nonsignificant trend toward more neurologic complications was noted in group I. The Kaplan-Meier survival estimate at 1 year was similar between the 2 groups (63% for group I vs 71% for group II).The presence of a reverse Blalock-Taussig shunt was not associated with more adverse events than those without. Gradual retrograde arch obstruction occurs commonly in palliated infants with aortic atresia. A reverse Blalock-Taussig shunt might play an important role to address the potential of retrograde obstruction, augmenting arch blood flow.

    View details for DOI 10.1016/j.jtcvs.2012.11.029

    View details for PubMedID 23228402

  • Fate of the ductal stent after hybrid palliation for hypoplastic left heart syndrome. The Annals of thoracic surgery Baba, K., Chaturvedi, R., Lee, K. J., Caldarone, C. A., Benson, L. N. 2013; 95 (5): 1660-4


    Ductal stenting plays a central role in hybrid palliation (with bilateral pulmonary artery [PA] banding) for hypoplastic left heart syndrome (HLHS). The "natural" history of ductal stent is relatively unknown.We retrospectively reviewed 37 neonates with HLHS or its variants who underwent hybrid palliation between January 2004 and March 2010.Forty-nine ductal stents were deployed in 37 neonates. A single stent was implanted in 26, 2 in 10, and 3 in 1 neonate at the index procedure. There were 5 neonates (13.5%) who required reintervention on the stent with an additional implant; 4 stents were placed proximally (PA-end) and 1 on the aorta side. No infant required reintervention on the stent if the implant covered from the PA junction to beyond the aortic isthmus. There were 2 infants (5.4%) who developed retrograde arch obstruction. Of the cohort, 9 died before stage II, 1 had a bidirectional cavopulmonary shunt after conversion to a Norwood circulation, and 27 underwent comprehensive stage II. In 24 infants who did not require an additional stent, duct velocity increased during follow-up (p < 0.001). Stent position was altered distally in relation to the anterior border of the trachea with child growth.The stent should cover the full length of the duct from the PA junction to beyond the arch isthmus to reduce reintervention rates. Such stents tend to have progressive stenosis and move distally with child growth. However, lower body blood flow appears well maintained until the time of a comprehensive stage II repair.

    View details for DOI 10.1016/j.athoracsur.2013.02.002

    View details for PubMedID 23506633

  • Systemic blood pressure after stent management for arch coarctation implications for clinical care. JACC. Cardiovascular interventions Morgan, G. J., Lee, K. J., Chaturvedi, R., Bradley, T. J., Mertens, L., Benson, L. 2013; 6 (2): 192-201


    The goal of this study was to prospectively assess blood pressure (BP) and echocardiographic parameters to delineate the incidence and nature of the hypertension burden in this cohort.Few data are available on the long-term outcomes of aortic stenting.Thirty-one patients with successfully stented coarctation during childhood (mean age 12.4 years) underwent 24-h ambulatory BP monitoring (ABPM), exercise BP measurement, and echocardiographic assessment.Mean time after stent implantation was 5.3 ± 4 years. Hypertension was noted on one-off right-arm BP assessment in 3 patients (10%), but on the basis of the 24-h ABPM assessment in 14 patients (45%). Twenty-four of 31 patients (80%) had an abnormally elevated exercise BP response. Peak exercise BP correlated with left ventricular mass index (r = 0.51; p < 0.05), which was also significantly increased in the entire cohort (mean = 91.3 g/m(2); p < 0.05). In patients with significant somatic growth since implantation, the indexed diameter of the stent (to aortic diameter) had significantly decreased from the 48th percentile at the implantation to the 4th percentile during the study (p < 0.05). There was no difference in any parameter between patients with native or those with recurrent coarctation.Hypertension is endemic in patients with stented coarctation, irrespective of the absence of residual obstruction. Due to abnormal BP homeostasis, hypertension should be aggressively pursued by ABPM assessment and exercise stress testing in this population. Relative hypoplasia of the stented arch after somatic growth may contribute to this tendency and should provoke consideration of elective serial redilation of coarctation stents.

    View details for DOI 10.1016/j.jcin.2012.10.009

    View details for PubMedID 23428013

  • Aortopulmonary collateral flow volume affects early postoperative outcome after Fontan completion: a multimodality study. The Journal of thoracic and cardiovascular surgery Grosse-Wortmann, L., Drolet, C., Dragulescu, A., Kotani, Y., Chaturvedi, R., Lee, K. J., Mertens, L., Taylor, K., La Rotta, G., van Arsdell, G., Redington, A., Yoo, S. J. 2012; 144 (6): 1329-36


    Aortopulmonary collaterals are a frequent phenomenon in patients after bidirectional cavopulmonary connection. The aortopulmonary collateral flow volume can be quantified using cardiac magnetic resonance imaging. However, the significance of aortopulmonary collateral flow for the postoperative outcome after total cavopulmonary connection is unclear and was sought to be determined.The data from 33 patients were prospectively studied with cardiac magnetic resonance, echocardiography, and cardiac catheterization before the total cavopulmonary connection operation. The early postoperative outcomes after total cavopulmonary connection completion were recorded.Aortopulmonary collateral flow was 1.59 L/min/m(2) ± 0.65 L/min/m(2) (range, 0.54 L/min/m(2)-3.34 L/min/m(2)), constituting 43% ± 13% (range, 12-87%) of pulmonary blood flow and 35% ± 12% (range, 11-62%) of the cardiac index, resulting in a pulmonary blood flow/systemic blood flow ratio of 1.06 ± 0.17 (range, 0.79-1.55). The aortopulmonary collateral flow correlated with pulmonary blood flow/systemic blood flow ratio (r = 0.69, P < .0001), oxygen saturation (r = 0.42, P = .018), and cardiac index (r = 0.53, P = .002). Of the 36 patients, 24 underwent fenestrated total cavopulmonary connection during the study period. The aortopulmonary collateral flow, relative to the cardiac index, correlated with the duration of hospital stay (r = 0.48, P = .02) and pleural drainage (r = 0.45, P = .03). Patients whose pleural drainage lasted 1 week or less had less aortopulmonary collateral flow before the Fontan operation than those with a longer period until chest tube removal (1.23 L/min/m(2) ± 0.38 L/min/m(2) vs 1.73 L/min/m(2) ± 0.76 L/min/m(2); P = .03). Compared with a contemporary group of total cavopulmonary connection patients with fenestration in their extracardiac conduit who were studied prospectively, with a similar protocol, the bidirectional cavopulmonary connection had a greater amount of aortopulmonary collateral flow (1.59 L/min/m(2) ± 0.65 L/min/m(2) vs 1.30 L/min/m(2) ± 0.57 L/min/m(2), P = .04).Patients after bidirectional cavopulmonary connection routinely acquire a large amount of aortopulmonary collateral flow. The hemodynamic consequences of aortopulmonary collateral flow translate into adverse outcomes early after total cavopulmonary connection completion.

    View details for DOI 10.1016/j.jtcvs.2012.03.032

    View details for PubMedID 22502974

  • Hybrid versus Norwood strategies for single-ventricle palliation. Circulation Baba, K., Kotani, Y., Chetan, D., Chaturvedi, R. R., Lee, K. J., Benson, L. N., Grosse-Wortmann, L., Van Arsdell, G. S., Caldarone, C. A., Honjo, O. 2012; 126 (11 Suppl 1): S123-31


    Hybrid and Norwood strategies differ substantially in terms of stage II palliative procedures. We sought to compare these strategies with an emphasis on survival and reintervention after stage II and subsequent Fontan completion.Of 110 neonates with functionally single-ventricle physiology who underwent stage I palliation between 2004 and 2010, 75 (69%) infants (Norwood, n=43; hybrid, n=32) who subsequently underwent stage II palliation were studied. Survival and reintervention rates after stage II palliation, anatomic and physiologic variables at pre-Fontan assessment, and Fontan outcomes were compared between the groups. Predictors for reintervention were analyzed. Freedom from death/transplant after stage II palliation was equivalent between the groups (Norwood, 80.4% versus hybrid, 85.6% at 3 years, P=0.66). Hybrid patients had a higher pulmonary artery (PA) reintervention rate (P=0.003) and lower Nakata index at pre-Fontan evaluation (P=0.015). Aortic arch and atrioventricular valve reinterventions were not different between the groups. Ventricular end-diastolic pressure, mean PA pressure, and ventricular function were equivalent at pre-Fontan assessment. There were no deaths after Fontan completion in either group (Norwood, n=25, hybrid, n=14).Survival after stage II palliation and subsequent Fontan completion is equivalent between the groups. The hybrid group had a higher PA reintervention rate and smaller PA size. Both strategies achieved adequate physiology for Fontan completion. Evolution of the hybrid strategy requires refinement to provide optimal PA growth.

    View details for DOI 10.1161/CIRCULATIONAHA.111.084616

    View details for PubMedID 22965972

  • The fellows stitch: large caliber venous hemostasis in pediatric practice. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Morgan, G. J., Waragai, T., Eastaugh, L., Chaturvedi, R. C., Lee, K. J., Benson, L. 2012; 80 (1): 79-82


    To analyze safety and efficiency of a subcutaneous figure of eight suture for hemostasis after large caliber venous sheath access in children.Vascular complications remain a significant cause of morbidity after pediatric cardiac catheterization. In an attempt to reduce such complications and yet improve lab efficiency and decrease length of stay, various techniques have been applied to improve time to hemostasis.Prospectively recorded were vascular complications and hemostasis times in children where hemostasis was attempted using a figure of eight subcutaneous suture following large caliber venous cannulation. These were compared to a matched group achieving hemostasis using standard manual pressure techniques. Vascular ultrasound assessments were performed within 24 hr of hemostasis in both groups.Thirty-two subcutaneous sutures were placed in 26 children, mean weights 31.9 kg [median (range): 29.4 (8.4 to 96) kg], with a mean sheath French size of 9.2 [8; (6 to 22)], 11 >10 French, compared to 33 sheaths in 30 cases using manual compression, mean sheath French size 9.1 (9; (6 to 13), with 10 cases ≥10 French. The mean and median times to hemostasis were shorter in the suture group: 13.6 min (P < 0.05) and 10 min (P < 0.05), respectively. Vascular complication rate was also lower in the suture group (n = 0) compared with the control group (n = 2) but did not achieve statistical significance.A subcutaneous figure of eight suture hemostasis strategy can provide a safe and efficient method for large caliber venous hemostasis in a pediatric practice with improved hemostasis times and no additional morbidity.

    View details for DOI 10.1002/ccd.23406

    View details for PubMedID 22105903

  • Delayed repair of right atrial isomerism with obstructed total anomalous pulmonary venous drainage by hybrid stent insertion between the left-sided atrium and pulmonary venous confluence. The Journal of thoracic and cardiovascular surgery Chaturvedi, R. R., Van Arsdell, G. S., Jacques, F., Lee, K. J. 2012; 144 (1): 271-3

    View details for DOI 10.1016/j.jtcvs.2011.12.056

    View details for PubMedID 22381351

  • The impact of additional epicardial imaging to transesophageal echocardiography on intraoperative detection of residual lesions in congenital heart surgery. The Journal of thoracic and cardiovascular surgery Dragulescu, A., Golding, F., Van Arsdell, G., Caldarone, C., Mertens, L., Al-Radi, O., Lee, K. J. 2012; 143 (2): 361-7


    Transesophageal echocardiography is the primary intraoperative imaging modality used to evaluate cardiac surgery. Its predecessor, epicardial echocardiography, enables visualization of certain cardiovascular structures that are beyond the visual scope of transesophageal echocardiography. We review the current use of epicardial echocardiography to analyze its contemporary application and benefit.A retrospective review of the intraoperative echocardiograms of 1204 children undergoing bypass cardiovascular surgery between January 2007 and December 2009 was performed. The incidence of epicardial echocardiography use, intraoperative revisions, and early reinterventions were analyzed.Epicardial echocardiography was performed in 7.9% of all intraoperative studies: epicardial echocardiography alone (n = 38) and transesophageal echocardiography + epicardial echocardiography (n = 57). Epicardial echocardiography alone was performed in patients with contraindications for transesophageal echocardiography. In the transesophageal echocardiography + epicardial echocardiography group, indications to obtain additional information by epicardial echocardiography were for the assessment of branch pulmonary arteries (40%), coronary arteries (28%), aortic arch/Blalock-Taussig shunt (14%), Glenn/Fontan circuit (9%), pulmonary veins/baffles (7%), and residual ventricular septal defects (1.7%). The overall intraoperative surgical revision incidence was 10.2%, consisting of 21% of the transesophageal echocardiography + epicardial echocardiography group, 5.3% of the epicardial echocardiography alone group (P = .01), and 9.8% of transesophageal echocardiography alone group (P = .02). Intraoperative revisions indicated after epicardial echocardiography were mostly related to extracardiac structures (77%), whereas they were mostly related to intracardiac structures in the transesophageal echocardiography alone group (80.7%) (P = .0002). Early reintervention was indicated mostly for pulmonary artery and Glenn obstructions, the majority (75%) with previously known stenosis or interventions on the pulmonary arteries.Epicardial echocardiography detects residual intraoperative lesions not visualized by transesophageal echocardiography, most frequently related to pulmonary arteries. Its use, in addition to standard transesophageal echocardiography, may decrease the need for early reintervention.

    View details for DOI 10.1016/j.jtcvs.2011.06.010

    View details for PubMedID 21752399

  • Acute effects of the ACE inhibitor enalaprilat on the pulmonary, cerebral and systemic blood flow and resistance after the bidirectional cavopulmonary connection. Heart (British Cardiac Society) Lee, K. J., Yoo, S. J., Holtby, H., Grant, B., Mroczek, D., Wong, D., Grosse-Wortmann, L., Benson, L. N., Chaturvedi, R. R. 2011; 97 (16): 1343-8


    The bidirectional cavopulmonary connection (BCPC) is used in the staged palliation of univentricular hearts and places the cerebral and pulmonary vascular beds in series. Angiotensin-converting enzyme inhibitors (ACEI) are often used in this complex circulation, but the effects of their vasodilation are unclear.Assessment of the acute response of perfusion pressure, flow and resistance across the systemic, cerebral and pulmonary vascular beds to ACEI in patients with a BCPC.Prospective interventional study.Single tertiary care centre.12 patients with a BCPC (median age 28 months, weight 11.8 kg) undergoing a pre-Fontan catheterisation with MRI measurement of flows.Intravenous enalaprilat 0.005 or 0.01 mg/kg.Enalaprilat increased descending aorta flow (median 21.6%, p=0.0005), decreased total pulmonary vein flow (median 10.6%, p=0.025), and both superior caval vein flow (median 8.6%, p=0.065) and aortopulmonary collateral flow (median 15.5%, p=0.077) tended to decrease. Total cardiac output was unchanged (p=0.57). Systemic vascular resistance (median 41.9%, p=0.0005) and cerebral vascular resistance (median 23.4%, p=0.0005) decreased, but pulmonary vascular resistance (p=0.73) showed little change. There was evidence of autoregulation of cerebral blood flow. The proportion of descending aortic flow to total cardiac output increased (median 27 to 35%, p=0.001). Systemic oxygen saturation decreased from 87% to 83% (p=0.02).Enalaprilat did not increase total cardiac output but redistributed flow to the lower body, with a concomitant decrease in arterial oxygen saturation. It is difficult to increase cardiac output in patients with a BCPC and ACEI should be used with caution in those with borderline aortic saturations.

    View details for DOI 10.1136/hrt.2011.225656

    View details for PubMedID 21646245

  • Vascular hemostasis bandage compared to standard manual compression after cardiac catheterization in children. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Waragai, T., Morgan, G., Ralston, T., Chaturvedi, R., Lee, K. J., Benson, L. 2011; 78 (2): 262-6


    Femoral venous and arterial approaches are the commonly used to obtain vascular access for pediatric cardiac catheterization. Hemostasis after catheter removal is usually obtained by manual compression. However, this technique is time consuming and at times painful. Although several closure devices are available for adults, they are not widely applicable in children.To evaluate the safety and efficacy of a microporous polysaccharide hemospheres hemostasis (MPH) bandage compared to manual compression.Prospective randomized study, involving 112 children after cardiac catheterization. One group received the MPH bandage, another manual compression. Compression time was predetermined by the size of sheath plus one minute. Success was defined as no bleeding or hematoma formation. If bleeding continued, compression was continued as needed and time to hemostasis recorded. Informed consent was obtained prior to randomization. Group comparisons were performed with a Student's t, Pearson's Chi Square, and Fisher's exact test as appropriate.Fewer children required a compression time of >15 min (P = 0.006) and more had a shorter time to hemostasis (P = 0.003) in the MPH group for venous access control. Time to hemostasis was also shorter in the MPH (P = 0.048) in arterial access cases, but the number of children requiring a compression time >15 min was the same. Complications including hematoma formation in each group were similar.The MPH bandage allows a shorter time to achieve hemostasis compared to manual compression. This improves turnaround time and laboratory efficiency.

    View details for DOI 10.1002/ccd.23057

    View details for PubMedID 21538780

  • A randomized controlled trial of motavizumab versus palivizumab for the prophylaxis of serious respiratory syncytial virus disease in children with hemodynamically significant congenital heart disease. Pediatric research Feltes, T. F., Sondheimer, H. M., Tulloh, R. M., Harris, B. S., Jensen, K. M., Losonsky, G. A., Griffin, M. P. 2011; 70 (2): 186-91


    Children with hemodynamically significant congenital heart disease (CHD) are at risk for serious respiratory syncytial virus (RSV) disease. This study was designed to assess the safety and tolerability of motavizumab versus palivizumab in children with CHD and was not powered for efficacy. Patients (n = 1236) aged ≤24 mo were randomized to receive five monthly doses (15 mg/kg) of motavizumab or palivizumab during the RSV season. Adverse events (AEs) and serious AEs (SAEs) were recorded through 30 d after the last dose. RSV hospitalizations and RSV outpatient medically attended lower respiratory tract infections (MALRI; season 2) were summarized. Approximately 93 and 50% of patients reported an AE or SAE, respectively. Skin events occurred in 19.3% of motavizumab recipients and 16.2% of palivizumab recipients. Rates of hospitalizations and RSV MALRI were similar between treatment groups [relative risk (RR): 0.75; 95% CI, 0.34-1.59 and RR: 0.49; 95% CI, 0.10-1.99, respectively; both p > 0.05]. Motavizumab and palivizumab had similar safety profiles in children with hemodynamically significantly CHD; with the exception of skin events which were increased in motavizumab recipients. Safety and efficacy were consistent with another study comparing motavizumab with palivizumab in premature infants without CHD.

    View details for DOI 10.1203/PDR.0b013e318220a553

    View details for PubMedID 21522037

  • A biodegradable device (BioSTAR) for atrial septal defect closure in children. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Morgan, G., Lee, K. J., Chaturvedi, R., Benson, L. 2010; 76 (2): 241-5


    Percutaneous closure of atrial defects (ASD) has evolved as the treatment of choice for the majority of defects and patent oval foramens. The BioSTAR biodegradable implant avoids many issues associated with devices containing substantial amounts of metal.Reviewed was a consecutive series of 10 ASD occlusions in a pediatric population with the BioSTAR biodegradable device. All implantations were performed by one operator. The inclusion criterion was a balloon stretched ASD diameter of < or =16 mm. Procedural data and acute and early-term closure rates were retrospectively matched to a cohort of children having defect closure using the Amplatzer Septal Occluder (ASO).Acute and 6 month follow up closure rates for the BioSTAR were 90% and 100% vs. 100% and 100% closure with the ASO implants. There was a statistically significant difference in the median procedure time (52 min: BioSTAR; 39.5 min: ASO device, P < 0.05), with fluoroscopy times slightly longer for the BioSTAR group (6.7 min vs. 6.1 min, P = ns). There were no significant complications in either group.The BioSTAR implant can achieve comparable closure rates to the ASO in small- to moderate-atrial septal defects with only a minimal skeleton of foreign material remaining after 6 months. Longer fluoroscopy and procedure times were a drawback; however, these should improve with familiarity with the implant and deployment system.

    View details for DOI 10.1002/ccd.22517

    View details for PubMedID 20665870

  • Percutaneous pulmonary valve implantation within bioprosthetic valves. European heart journal Asoh, K., Walsh, M., Hickey, E., Nagiub, M., Chaturvedi, R., Lee, K. J., Benson, L. N. 2010; 31 (11): 1404-9


    Replacement of bioprosthetic valves in the right ventricular (RV) outflow tract (RVOT) is inevitable due to acquired valvar dysfunction. Percutaneous pulmonary valve implantation (PPVI) may result in acceptable clinical improvement avoiding surgical reintervention. To report outcomes of PPVI in dysfunctional surgically implanted bioprosthetic valves.All children undergoing PPVI into a bioprosthetic pulmonary valve between October 2005 and February 2008 were reviewed. Acute haemodynamic changes were compared and an analysis of variance applied to assess changes in ventricular geometry and pressure over time. Fourteen children (seven males), median weight 57.8 kg and 14.7 years of age were identified, with an echocardiographic RVOT gradient of 59.6 +/- 26.8 mmHg and a pulmonary regurgitation (PR) grade of 3.6 +/- 0.8 (out of 4). Implantation was successful in all. Twenty-four hours after implantation, there was a significant improvement in RV pressure (RVP) (from 82.2 +/- 15.6 to 59.4 +/- 9.9 mmHg, P < 0.001) and degree of PR to 0.6 +/- 0.9 (P < 0.001). Mean hospital stay was 2.0 +/- 0.4 days. Freedom from reintervention was 92 and 89% at 1 and 2 years, respectively. Follow-up echocardiography (mean 12.9 +/- 9.8 months) revealed a further reduction in RVP (P < 0.001) and RVOT gradients (P < 0.001) and an increase in left ventricular end-diastolic volume (P= 0.01) and aortic valve annulus diameters (P < 0.001).Percutaneous pulmonary valve implantation for RVOT dysfunction in a previously implanted prosthetic valve is feasible and safe. Short-term follow-up data are encouraging, yet longer-term information is required to determine if this form of palliation has a significant impact on management strategies.

    View details for DOI 10.1093/eurheartj/ehq056

    View details for PubMedID 20231157

  • Percutaneous pulmonary valve implantation in the young 2-year follow-up. JACC. Cardiovascular interventions Vezmar, M., Chaturvedi, R., Lee, K. J., Almeida, C., Manlhiot, C., McCrindle, B. W., Horlick, E. M., Benson, L. N. 2010; 3 (4): 439-48


    The aim of this study was to investigate physiological and clinical consequences of percutaneous pulmonary valve implantation (PPVI) in patients with chronic right ventricular outflow tract (RVOT) obstruction and volume overload.The PPVI is a nonsurgical technique to address RVOT conduit dysfunction.Twenty-eight adolescents (median age 14.9 years; age range 10.9 to 19 years) underwent PPVI due to RVOT stenosis and/or pulmonary regurgitation (PR). Before and after PPVI echocardiographic and magnetic resonance imaging, cardiopulmonary exercise tests were obtained.The RVOT gradient (p < 0.001) and right ventricular (RV) systolic pressure decreased (p < 0.001), acutely. Magnetic resonance imaging (median 6 months) documented reduction in RV end-diastolic (149 +/- 49 ml/m(2) vs. 114 +/- 35 ml/m(2), p < 0.005) volume, increases in left ventricular (LV) end-diastolic (p < 0.007) volume and cardiac output (RV: p < 0.04 and LV: p < 0.02), and reduced PR fraction (24 +/- 10% to 7 +/- 7%, p < 0.0001). Symptoms, aerobic exercise performance (maximal oxygen consumption: p < 0.0001) and ventilatory response to carbon dioxide production (p < 0.003) improved. After 24 months, echocardiography demonstrated the RV/systemic-pressure ratio, and RVOT peak pressure gradient reductions persisted, and PR was absent in 93% (n = 12 of 13) of the cohort. Freedom from surgery was 91%, 83%, and 83%, and freedom from transcatheter reintervention was 91%, 80%, and 80%, at 12, 24, and 36 months, respectively. There were no acute device-related complications, with stent fractures noted in 10.8%.Percutaneous pulmonary valve implantation is feasible and safe in the young with dysfunctional RVOT conduits. An improvement in symptoms, hemodynamic status, and objective findings of exercise performance occurs. Early follow-up demonstrates persistent improvement in ventricular parameters, PR, and objective exercise capacity.

    View details for DOI 10.1016/j.jcin.2010.02.003

    View details for PubMedID 20398873

  • Balloon dilation of pulmonary valve stenosis in infants less than 3 kg: a 20-year experience. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Karagoz, T., Asoh, K., Hickey, E., Chaturvedi, R., Lee, K. J., Nykanen, D., Benson, L. 2009; 74 (5): 753-61


    This study focused on the anatomical features and outcomes of percutaneous pulmonary valve balloon dilation (PVD) in newborns < or = 3 kg in weight.Although PVD is the treatment of choice for isolated pulmonary valve stenosis, there are no studies detailing technical, anatomical, and outcome variables in the smallest of infants undergoing the procedure.A retrospective, consecutive review of all initial and follow-up echocardiograms, catheterization data, cineangiograms, and surgical records of all neonates less than 3 kg.Fifty infants underwent 55 PVD's, median age 7 days and weight 2.7 kg. Congestive heart failure and/or cyanosis were present in 55%, 46% prostaglandin dependent, with 28% having a hypoplastic right ventricle. The pulmonary valve diameter median z-score was -2.6, (range -5.8 to 1.2, P < 0.0001 vs. normal). The procedure was accomplished in all but one child, using a balloon to annulus ratio of 1.3 (range 1.1 to 1.7). There was a reduction in both the peak right ventricular systolic pressure (P < 0.0001) and outflow gradient (P < 0.0001). There was no procedure related mortality, although six children died in long-term follow-up (14%). Reintervention was necessary in 15 infants within 8 months of the procedure. Pulmonary regurgitation, present in 36% after the procedure, showed a gradual increase over time while outflow gradients decreased and valve annular dimensions increased toward normal.In infants < or = 3 kg, PVD is safe and effective. A large proportion remains free from surgery (76% at 10 years). Small valve annular dimensions show catch up growth with time.

    View details for DOI 10.1002/ccd.22064

    View details for PubMedID 19496127

  • Complete congenital obstruction of a scimitar vein in an infant with severe respiratory failure. Cardiology in the young Bauch, A., Lee, K. J., Yoo, S. J. 2009; 19 (5): 524-6


    We report an infant of 3 1/2 months with complete obstruction of the venous component of the scimitar syndrome, a large atrial septal defect within the oval fossa, a common left pulmonary vein, and pulmonary hypertension. To the best of our knowledge, ours is the first description of complete congenital obstruction of a scimitar vein.

    View details for DOI 10.1017/S1047951109990825

    View details for PubMedID 19671218

  • Cutting balloon angioplasty for aortic coarctation. The Journal of invasive cardiology Ozawa, A., Predescu, D., Chaturvedi, R., Lee, K. J., Benson, L. N. 2009; 21 (6): 295-9


    Cutting balloon angioplasty (CBA) has improved outcomes for resistant stenotic vascular lesions in adult coronary artery disease. Application of this technique in coarctation of the aorta (CoA) in children has not been reported.We sought to review the safety, efficacy and outcomes of CBA in the setting of CoA.Between February 2004 and October 2007, 8 children (4 males) underwent 10 procedures. The median age was 5.5 months (range: 2.5 months to 5 years) and median weight 7.5 kg (range: 4.1-13.3 kg). Two children had native CoA. CBA was employed due to a persistent waist after conventional balloon angioplasty (6 procedures) or as the primary dilatation (4 procedures). The cutting balloon diameter was a median 143% (range: 108-222%) of the diameter of the lesion. After dilatation, all children underwent further conventional balloon angioplasty. The CoA median diameter increased from 2.8 mm (range: 1.8-4 mm) to 4 mm (range: 2.9-6.7 mm; p = 0.0018), and the arm-to-leg blood systolic blood pressure gradient decreased from 38.5 mmHg (range: 2-70 mmHg) to 7 mmHg (0-30 mmHg; p < 0.0001). The median follow-up period was 4.6 months (range: 0.5-15.6 months), and 2 children required a second balloon dilatation. No aneurysm formation was observed acutely, although 2 children each developed a femoral arteriovenous fistula or a pseudoaneurysm.This early experience suggests that CBA is acutely safe and can be effective in the management of recalcitrant coarctation lesions in the young.

    View details for PubMedID 19494410

  • Rapamycin-eluting stents in the arterial duct: experimental observations in the pig model. Circulation Lee, K. J., Hinek, A., Chaturvedi, R. R., Almeida, C. L., Honjo, O., Koren, G., Benson, L. N. 2009; 119 (15): 2078-85


    Maintaining arterial duct patency by stent implantation may be advantageous in congenital heart disease management algorithms. Rapamycin, an immunosuppressant drug that demonstrates antiproliferative properties and inhibits smooth muscle cell migration, may deter the intimal hyperplasia that occurs during spontaneous closure and after-stent implantation of the arterial duct.Twenty-eight Yorkshire piglets (7 to 11 days old; weight, 2.2 to 4.9 kg) underwent stent implantation of the arterial duct (rapamycin-eluting (n=14) or bare metal (n=14) stents, 3.5-mm diameter) and were euthanized at 2, 4, and 6 weeks. Dissected arterial ducts were analyzed for lumen diameter, smooth muscle cell, and extracellular matrix components. Isolated arterial duct-derived smooth muscle cells were cultured in the presence or absence of rapamycin. Cellular proliferation rates were assessed by Ki-67 detection and [(3)H]-thymidine incorporation. No significant neointimal proliferation was present in either stent type at 2 weeks. At 4 weeks, the median luminal diameters of the bare metal stents were 87% (P=0.009), 54% (P=0.004), and 77% (P=0.004) that of the drug-eluting stents at the middle and aortic and pulmonary artery ends, respectively. At 6 weeks, the median luminal diameters of the bare metal stents were 0% (P=0.18), 5% (P=0.25), and 61% (P=0.13) that of the drug-eluting stents at the same respective levels. Complete histological occlusion was found in at least 1 level of the lumen in 9 pigs: 1 (17%) in the BMS group at 4 weeks, 5 (83%) in the BMS group at 6 weeks, and 3 (50%) in the DES group at 6 weeks. In vitro studies demonstrated 50%-lower proliferation rates in rapamycin-treated cultures of duct-derived smooth muscle cell cultures (P<0.001).Rapamycin has antiproliferative actions on the arterial duct. Drug-eluting stents may be a more efficient tool than current palliative options for maintaining patency in critically duct-dependent states, but there may be a finite time-related benefit.

    View details for DOI 10.1161/CIRCULATIONAHA.107.737734

    View details for PubMedID 19349326

  • Stenting of the right ventricular outflow tract in the symptomatic infant with tetralogy of Fallot. Heart (British Cardiac Society) Dohlen, G., Chaturvedi, R. R., Benson, L. N., Ozawa, A., Van Arsdell, G. S., Fruitman, D. S., Lee, K. J. 2009; 95 (2): 142-7


    Repair of neonatal tetralogy of Fallot (TOF) has low mortality. Debate continues regarding the initial management of cyanotic or duct-dependent infants with TOF and adverse risk factors. While repair can and has been performed in these patients, it is associated with increased morbidity.We review the effectiveness of right ventricular outflow tract (RVOT) stenting in the symptomatic young infant with TOF.Clinical, echocardiographic, angiographic and haemodynamic data were reviewed for nine patients who underwent 11 RVOT stenting procedures from October 1994 to August 2007.The pulmonary valve was deemed unsalvageable in all patients (median valve diameter 3.7 mm (range 2.7-4.2), Z-score -6.7 (range -9.7 to -5.4). RVOT stenting improved arterial oxygen saturation from a median of 73% (60-85%) to 94% (90-98%) (p = 0.008). Median Z-score for the left pulmonary artery increased from -4.9 (-7.8 to -2.4) before stent implantation to -1.5 (-4.2 to -0.2) (p = 0.02) before surgical repair. Median Z-score for the right pulmonary artery increased from -3.7 (-6.8 to -1.9) to -0.8 (-2.5 to 0.1) (p = 0.008). Median Nakata index increased from 56 mm(2)/m(2) (21-77) to 150 mm(2)/m(2) (123-231) (p = 0.008). There were no procedural complications. Six patients have undergone successful repair. There were no deaths.In the symptomatic young infant with TOF, stenting of the RVOT provides a safe and effective management strategy, improving arterial oxygen saturation and encouraging pulmonary artery growth.

    View details for DOI 10.1136/hrt.2007.135723

    View details for PubMedID 18332061

  • Implantation of drug-eluting stents for relief of obstructed infra-cardiac totally anomalous pulmonary venous connection in isomerism of the right atrial appendages. Cardiology in the young Wong, D. T., Yoo, S. J., Lee, K. J. 2008; 18 (6): 628-30


    We describe an infant with severe obstruction of infra-cardiac totally anomalous pulmonary venous connection associated with right isomerism, atrioventricular septal defect, pulmonary atresia, and multiple aortopulmonary collateral arteries. Implantation of a stent into the obstructed descending vertical vein provided effective palliation, with a dramatic increase in saturations of oxygen obviating the need for urgent high-risk surgery.

    View details for DOI 10.1017/S1047951108003120

    View details for PubMedID 18828956

  • Borderline hypoplasia of the left ventricle in neonates: insights for decision-making from functional assessment with magnetic resonance imaging. The Journal of thoracic and cardiovascular surgery Grosse-Wortmann, L., Yun, T. J., Al-Radi, O., Kim, S., Nii, M., Lee, K. J., Redington, A., Yoo, S. J., van Arsdell, G. 2008; 136 (6): 1429-36


    We sought to compare the usefulness of echocardiography and magnetic resonance imaging in neonates with a borderline small left ventricle.The preoperative magnetic resonance and echocardiography studies of 20 consecutive patients (mean age 10 +/- 9 days) undergoing magnetic resonance imaging were analyzed. The diagnoses were aortic stenosis (n = 3), hypoplastic left heart complex (n = 12), and unbalanced atrioventricular septal defect (n = 5). The magnetic resonance imaging protocol included ventricular volumetry, flow measurements, and angiography. Potential left ventricular volumes, assuming an ideal geometric shape, were calculated by mathematically "unfolding" the compressed left ventricle.Left ventricular end-diastolic volume was 16.0 +/- 7.0 mL/m(2) of body surface area by echocardiography and 33.5 +/- 15.5 mL/m(2) by magnetic resonance imaging. Echocardiography consistently underestimated left ventricular volume and did not correlate with magnetic resonance. Of all echocardiographic parameters, mitral valve z-score was the best predictor of left ventricular end-diastolic volume by magnetic resonance (r = 0.77; P = .02). The average potential volume increase was 8.8% for aortic stenosis, 35.0% for atrioventricular septal defect and 23.0% for hypoplastic left heart complex patients. Aortic valve diameter did not correlate with flow volume in the ascending aorta. Sixteen (80%) of 20 patients underwent biventricular repair, without early mortality. Of these, only 5 (31.3%) had a preoperative left ventricular end-diastolic volume of more than 20 mL/m(2) by echocardiography.Magnetic resonance imaging is feasible in neonates with borderline left ventricular hypoplasia. Echocardiography does not accurately measure left ventricular hypoplasia in these patients and may unfairly preclude some patients from a biventricular repair in whom magnetic resonance is reassuring.

    View details for DOI 10.1016/j.jtcvs.2008.04.027

    View details for PubMedID 19114185

  • Complete heart block associated with device closure of perimembranous ventricular septal defects. The Journal of thoracic and cardiovascular surgery Predescu, D., Chaturvedi, R. R., Friedberg, M. K., Benson, L. N., Ozawa, A., Lee, K. J. 2008; 136 (5): 1223-8


    The development of the Amplatzer Membranous VSD Occluder (AGA Medical Corp, Plymouth, Minn) for closure of the perimembranous ventricular septal defect has ameliorated many of the technical difficulties of previous devices. Application of this new technology requires comparative evaluation with the current standard of surgical repair. We report our experience of complete heart block associated with device closure of a large perimembranous ventricular septal defect with unequivocal indications for intervention.We performed a retrospective review of 20 patients between January 2003 and August 2005 who underwent perimembranous ventricular septal defect device closure, 18 with hemodynamically large shunts meeting the surgical criteria for intervention. The median age was 1.6 years (range, 0.5-16.2 years), and the median weight was 9.7 kg (range, 6.2-43 kg).Acute complete shunt occlusion was achieved in all patients. There were no acute procedural complications. The median follow-up time was 23.1 months (range, 1-37.8 months). Four (22%) had complete heart block at 17 days, 4.2 months, 8.8 months, and 37.5 months after implantation, respectively. No risk factors were identified for development of complete heart block, including age, weight, trisomy 21, preceding conduction abnormalities, perimembranous ventricular septal defect size related to body surface area or device size, and progressive device flattening.Device closure of large perimembranous ventricular septal defects in infants and children with the Amplatzer Membranous VSD Occluder resulted in excellent closure rates but an unacceptably high rate of complete heart block.

    View details for DOI 10.1016/j.jtcvs.2008.02.037

    View details for PubMedID 19026807

  • Kaposiform hemangioendothelioma presenting antenatally with a pericardial effusion. Journal of pediatric hematology/oncology Walsh, M. A., Carcao, M., Pope, E., Lee, K. J. 2008; 30 (10): 761-3


    We describe an infant presenting with fetal pericardial effusion requiring in utero pericardiocentesis. Important postnatal clinical features included recurrent pericardial effusion, progressive stridor, thrombocytopenia, anemia, and a mediastinal mass surrounding the heart and coronary arteries. Investigations and management consisted of repeat pericardiocentesis, platelet and red blood cell transfusions, laryngoscopy, creation of a pericardial window, and biopsy of the mediastinal mass. Diagnosis was made of Kaposiform hemangioendothelioma surrounding the base of the heart, trachea, and esophagus as well as Kasabach-Merritt phenomenon. The infant responded well to treatment with vincristine and prednisone.

    View details for DOI 10.1097/MPH.0b013e318175c244

    View details for PubMedID 19011475

  • Complications of pediatric cardiac catheterization: a review in the current era. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Mehta, R., Lee, K. J., Chaturvedi, R., Benson, L. 2008; 72 (2): 278-85


    To determine types of complications and risks associated with pediatric cardiac catheterization in the current era.Pediatric cardiac catheterization is an important diagnostic and therapeutic tool. Although in the last decade, there have been significant improvements in technology and equipment, the risk for complications remains, adversely effecting outcomes.The clinical records of 11,073 children undergoing cardiac catheterizations between January 1994 and March 2006 were reviewed to identify procedures associated with complications within the first 24 h after catheterization. All children's electronic and paper chart records were reviewed to obtain demographic, procedural, and treatment data.A total of 858 (7.3%) complications (classified as major or minor) occurred in 816 studies (510 males, 63%), in children ranging in age from 8 h to 20 years (median 4.13 years). There were 195 major (22%) and 663 (78%) minor complications. Vascular complications represented the majority (n = 278; 32.4%) and were major in 53 instances (P < 0.0001). Twenty-five children died within 24 h (0.23% of total case numbers). Independent risk factors for a complication included young patient age (<6 months), male gender, inpatient status, and year of catheterization.Complications continue to be associated with pediatric cardiac catheterization, although overall incidence appears to be decreasing. Patient age, gender, and inpatient status continue to be risk factors for morbidity and mortality. Efforts at improving equipment for flexibility and size, and developing strategies for the use of alternative methods for catheter access should be encouraged.

    View details for DOI 10.1002/ccd.21580

    View details for PubMedID 18546231

  • Outcome and growth potential of left heart structures after neonatal intervention for aortic valve stenosis. Journal of the American College of Cardiology Han, R. K., Gurofsky, R. C., Lee, K. J., Dipchand, A. I., Williams, W. G., Smallhorn, J. F., McCrindle, B. W. 2007; 50 (25): 2406-14


    The purpose of this study was to determine trends of growth of left heart structures after intervention for neonatal aortic valve stenosis.The growth potential of left heart structures in neonatal aortic valve stenosis after relief of obstruction might influence risk for subsequent outcomes.From 1994 to 2004, 53 patients underwent neonatal (< or =30 days old) balloon aortic valve dilation. Factors associated with time-related outcomes (death, reintervention, aortic valve replacement) and longitudinal changes in normalized left heart dimensions were sought.The median age at intervention was 3.5 days (range 1 to 30 days). During a median follow-up of 3.2 years ranging up to 10.9 years, there were 31 reinterventions on the aortic valve in 21 (40%) patients and 7 deaths (13%). The presence of moderate or severe left ventricular (LV) endocardial fibroelastosis was the only independent predictor for time-related mortality (hazard ratio 22.1; p = 0.004), and a smaller initial aortic valve annulus z-score was a significant independent predictor for aortic valve replacement (hazard ratio 0.63 per 1-U change; p = 0.007). Aortic valve annulus, aortic sinus, and LV dimension z-scores significantly increased over time, whereas mitral valve z-scores remained below normal. The structure's initial z-score and concomitant size of other left heart structures were significant independent factors associated with subsequent z-scores.There is potential catch-up growth of the aortic valve and LV over time for neonates after intervention for aortic valve stenosis. However, the continued hypoplasia of the mitral valve warrants further consideration in the long-term management of these patients.

    View details for DOI 10.1016/j.jacc.2007.07.082

    View details for PubMedID 18154967

  • Radiofrequency perforation of the right ventricular outflow tract as a palliative strategy for pulmonary atresia with ventricular septal defect. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Walsh, M. A., Lee, K. J., Chaturvedi, R., Van Arsdell, G. S., Benson, L. N. 2007; 69 (7): 1015-20


    Radiofrequency perforation (RF) of the right ventricular outflow tract (RVOT), while an effective management strategy in children with an intact ventricular septum, has not been fully detailed in those presenting with a ventricular septal defect.To determine whether transcatheter perforation of the atretic pulmonary valve is an acceptable management strategy prior to surgical repair.Valve perforation was attempted in eight children seen between May 2000 and March 2006, five being infants between 1 and 9 days of age. In five children, this was the first of two procedures, the second a planned surgical correction. The RF was successful in six children with one child requiring additional stenting of the RVOT. Of these children, three attained a biventricular repair within the next year without additional palliative surgical procedures. Of the remaining three patients, one is awaiting surgical correction, one did not require further surgery, and one had this procedure as the only planned palliation. The two children in whom RF was not possible were referred for surgical augmentation of pulmonary blood flow.A treatment strategy that includes pulmonary valve perforation as initial palliation to increase pulmonary blood flow may be effective. Additional experience to better define those children who would benefit from this treatment algorithm is required.

    View details for DOI 10.1002/ccd.21119

    View details for PubMedID 17377999

  • Feasibility and clinical impact of transcatheter closure of interatrial communications after a fenestrated Fontan procedure: medium-term outcomes. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Pihkala, J., Yazaki, S., Mehta, R., Lee, K. J., Chaturvedi, R., McCrindle, B. W., Van Arsdell, G., Benson, L. N. 2007; 69 (7): 1007-14


    This study was to review an institutional experience with transcatheter closure of Fontan fenestrations and its impact on clinical care.An interatrial fenestration improves postoperative outcomes in high-risk children undergoing a Fontan repair. While technical feasibility has been well defined, the clinical impact of subsequent closure is not well defined.Transcatheter closure of a surgically created or additional interatrial communication was attempted in 152 children at a median interval of 13.8 months after surgery. The clinical records were reviewed for demographic and anatomical characteristics, previous surgeries; catheterization data, and status at latest follow-up.Mean oxygen saturation and right atrial pressure increased acutely from 87% +/- 5% to 96% +/- 3% (P < 0.001) and 12 +/- 2 mm Hg to 13 +/- 3 mm Hg (P < 0.001), respectively. Higher systemic venous atrial pressures after occlusion correlated with higher pulmonary artery pressures (P = 0.05) before the Fontan procedure and with higher right (P < 0.001) and left atrial (P = 0.001) and ventricular end-diastolic pressures (P < 0.001) immediately before occlusion. Complications included device malposition in 2 children, 1 child each had an air embolism and post-procedural bleeding, and each self-limiting and 1 child had acute ST elevation in inferior ECG leads because of occlusion of the acute marginal branch which was treated with angioplasty and placement of a stent. At follow-up (median 4.5 years), the mean oxygen saturation was 95% +/- 3%. Residual interatrial leaks were noted echocardiographically in 9%. Two children developed protein-losing enteropathy after fenestration closure. No deaths or strokes were observed in follow-up.Transcatheter occlusion of Fontan fenestrations is safe with acute and persistent improvements in oxygen saturations.

    View details for DOI 10.1002/ccd.20995

    View details for PubMedID 17421018

  • Neonatal rhabdomyoma causing right ventricular inflow obstruction with duct-dependent pulmonary blood flow: successful stenting of PDA. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Ilina, M. V., Jaeggi, E. T., Lee, K. J. 2007; 69 (6): 881-5


    We describe an infant with the antenatal diagnosis of a large intracardiac rhabdomyoma causing tricuspid inflow obstruction. Postnatal cyanosis and arterial hypoxemia prompted commencement of intravenous prostaglandin E1 with immediate improvement in saturations. Clinical and genetic testing confirmed diagnosis of tuberous sclerosis. To secure ductal patency, two tandem coronary stents were implanted via an antegrade approach. Several episodes of long RP atrio-ventricular re-entrant tachycardia were observed. At 7(1/2) months of age, the tumor was no longer obstructive to tricuspid inflow, ductal flow was highly restrictive and there was no recurrence of supraventricular tachycardia.

    View details for DOI 10.1002/ccd.21064

    View details for PubMedID 17436271

  • Femoral vein hemostasis in children using a suture-mediated closure device. Journal of interventional cardiology Ozawa, A., Chaturvedi, R., Lee, K. J., Benson, L. 2007; 20 (2): 164-7


    The safety and efficacy of a suture-mediated vascular closure device (Perclose, Abbott, Redwood City, CA) for hemostasis after percutaneous vascular access using >or=8-Fr sheath in the femoral vein after cardiac catheterization in children was assessed. Efficacy was determined by time to hemostasis and vessel integrity, using Doppler vascular ultrasound within 24 hours of the procedure. Forty children were randomized to treatment with either the closure device (n = 20, 10 males, weight 34.8 +/- 21 kg) or manual compression (n = 20, 10 males, weight 33.7 +/- 16 kg, P = 0.57 between groups for weight). Sheath sizes used were >or=8 French (8 Fr, n = 8; 9 Fr, n = 7; 10 Fr, n = 1; 11 Fr, n = 1; 12 Fr, n = 2; and 14 Fr, n = 1). Successful suture deployment was achieved in 14 of the 20 children. Mean time to hemostasis was 6.2 +/- 0.9 versus 14.9 +/- 1.1 minutes in controls (P = 0.003). Five of six unsuccessful deployments were in children with weights <20 kg. There were no differences in the occurrence of vascular complications (i.e., intraluminal thrombus) between the two groups as determined by ultrasound. A suture-mediated device appears safe and effective in achieving rapid vascular hemostasis even after the use of large sheath sizes in children.

    View details for DOI 10.1111/j.1540-8183.2007.00241.x

    View details for PubMedID 17391226

  • Presentation, management and outcomes of thrombosis for children with cardiomyopathy. The Canadian journal of cardiology McCrindle, B. W., Karamlou, T., Wong, H., Gangam, N., Trivedi, K. R., Lee, K. J., Benson, L. N. 2006; 22 (8): 685-90


    Thrombosis in children with dilated and inflammatory cardiomyopathy is an unpredictable complication with potentially important morbidity.To determine the prevalence, associated factors, management and outcomes of thrombosis in this setting.Data were obtained from review of medical records. Factors associated with thrombosis and the impact on outcome were sought.From 1990 to 1998, 66 patients that presented with dilated cardiomyopathy were followed for a median interval of 1.4 years (range 0 to 9.79 years) from first presentation. Thrombosis was diagnosed in four patients at presentation and in four patients during follow-up. Thrombosis was noted in one additional patient at examination after death. The overall nine-year period prevalence of thrombosis was 14%. Anticoagulation was started at presentation in 31% of patients. The mean left ventricular ejection fraction at presentation was significantly lower in those given anticoagulation (19+/-8%) versus those who were not (32+/-15%; P < 0.001). The mean ejection fraction at presentation was similar in those patients with (25+/-10%) versus those without thrombosis (28+/-15%; P = 0.44). During follow-up, 11 patients died and seven underwent cardiac transplantation. Kaplan-Meier estimates of freedom from death or transplantation were 88% at three months, 81% at one year and 70% at five years. Survival free of transplantation was not affected by thrombosis.Thrombosis is common in children with cardiomyopathy, can occur at any time in the patients' clinical course and is not related to clinical features or survival free of transplantation. The relevance and prevention of thrombosis in this setting remains unclear.

    View details for DOI 10.1016/s0828-282x(06)70937-0

    View details for PubMedID 16801999

    View details for PubMedCentralID PMC2560561

  • Late outcomes after pulmonary valve balloon dilatation in neonates, infants and children. The Journal of invasive cardiology Garty, Y., Veldtman, G., Lee, K., Benson, L. 2005; 17 (6): 318-22


    This review was designed to document late outcomes after percutaneous balloon dilation (PBD) of the pulmonary valve (PV) on infants and children.PBD is the treatment of choice for PV stenosis. While short and intermediate term results are excellent, late outcomes, with respect to growth of the right heart are poorly defined.Clinical data and serial echocardiograms were reviewed for children who had PBD between 1984 and 1992.One-hundred and fifty children were identified. PV gradients decreased from 62+/-29 to 23+/-20 mmHg (p<0.0001) and remained low during a mean follow-up of 11.9+/-3.1 (range 3.7 to 19.3 years). Freedom from re-intervention at 1, 10 and 15 years were: 90%, 83%, and 77%. Pulmonary regurgitation (PR) increased during follow-up such that 57% of children had moderate or severe PR at last follow-up. These children tended to have a smaller body surface area (0.52 vs. 0.82 m2, p=0.04), were younger (3.1 vs. 5.9 years, p=0.004), and less likely to be syndromic (p=0.04). Only children with severe PR demonstrated a significant increase in right ventricular (RV) size. Tricuspid and pulmonary annuli grew with the child's growth, the PV demonstrating catch-up growth (PV z-score: negative 1.3 vs. negative 0.7 at last follow-up, p=0.04).Following PBD in childhood, gradient reduction persists and RV structures grow appropriately in the majority of children. Although late PR occurs commonly, it is well tolerated. While life-long follow-up is essential, excellent outcome can be anticipated.

    View details for PubMedID 16003007

  • Transcatheter closure of atrial septal defects in children with a hypoplastic right ventricle. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Atiq, M., Lai, L., Lee, K. J., Benson, L. N. 2005; 64 (1): 112-6


    The efficacy and safety of device closure of atrial defects in children with complex congenital heart disease and a hypoplastic right ventricle have not been detailed. The objective of this study was to determine the clinical impact and outcomes of a staged surgical catheter-based management strategy. A retrospective analysis of 17 children with a hypoplastic right ventricle who had undergone cardiac catheterization and attempted device occlusion of an atrial defect was undertaken. Clinical data, anatomical diagnoses, previous surgeries, and interventions were noted. The clinical course and echocardiographic findings were compared before and after defect closure (6 +/- 4 months of follow-up). Nine children had pulmonary atresia with an intact ventricular septum, six had Ebstein's anomaly of the tricuspid valve, and two had isolated right ventricular hypoplasia. The mean age at defect closure was 6.6 +/- 3.4 years. Under general anesthesia, closure of the atrial defect was undertaken after initial temporary test occlusion. The Qp:Qs ratio before closure was 1.1 +/- 0.4. Oxygen saturation improved in all children from 91% +/- 1% to 98% +/- 1% (P < 0.0005). Mean right atrial pressure increased from 9 +/- 3 to 11 +/- 4 mm Hg after closure, but the difference was not statistically significant (P = 0.2). Follow-up revealed an increased right ventricular length (P = 0.009) and Z-score (P = 0.02), although no significant increase in the diameter of the tricuspid valve annulus was observed in children with pulmonary atresia. Right ventricular systolic pressures or systolic function did not change significantly during follow-up (P = 0.5 and 0.29, respectively). Exercise tolerance improved in all children and clinical evidence of right ventricular decompensation was absent. Catheter closure of atrial defects in children with a hypoplastic right ventricle is well tolerated, safe, and effective as a treatment strategy in the staged management.

    View details for DOI 10.1002/ccd.20245

    View details for PubMedID 15619280

  • Creation and enlargement of atrial defects in congenital heart disease Pediatric Cardiology Veldtman, G., Norgard, G., Wahlander, H., Garty, Y., Thabit, O., McCrindle, B., Lee, K., Benson, L. 2005
  • Lymphomatous involvement of the heart in children: two cases and a review of the literature. Journal of pediatric hematology/oncology Das, P. K., Grant, R., Malkin, D., Lee, K. J., Ngan, B., MacDonald, C. E., Carcao, M. 2004; 26 (12): 852-4


    Primary cardiac lymphoma (PCL) is a rare presentation of lymphoma in children. The emergency nature of its presentation (heart failure and arrhythmias) makes management of this entity difficult. The authors describe two children with lymphoma primarily involving the heart; one patient was a case of PCL and the other was a case of lymphoma involving the heart along with pelvic involvement. These two patients, together with a literature review on the topic, suggest that if the diagnosis of PCL is made early and treatment is expeditiously started, patients may do well.

    View details for PubMedID 15591913

  • Bladed balloon angioplasty for peripheral pulmonary artery stenosis. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Sugiyama, H., Veldtman, G. R., Norgard, G., Lee, K. J., Chaturvedi, R., Benson, L. N. 2004; 62 (1): 71-7


    Treatment for peripheral pulmonary artery stenosis is challenging, and conventional balloon angioplasty has not proved to be universally effective. Evaluated was the efficacy of bladed balloon (BB) dilation to address vessels resistant to conventional high-pressure (10-15 atm) balloon angioplasty (BA). Thirty-one procedures were performed on 14 children with age range 1 month to 15 years. The diameter of the BB ranged from 3 to 8 mm. After BB dilation, all children had subsequent conventional BA (balloon size range, 3-10 mm). The minimal lumen diameter (MLD) before and after the procedure, whether there was a waist at initial BA, and BB diameter-to-MLD ratio before the procedure were measured. A > 50% increase in MLD was considered successful. Four children had Williams syndrome, two children Alagille syndrome, five children Fallot's tetralogy, and three miscellaneous lesions. The resistant stenosis was located in the right central pulmonary artery in 6, right branch pulmonary artery in 7, left central pulmonary artery in 6, and left branch pulmonary artery in 12 lesions. Median BB diameter was 253% (117-440%) of the MLD and increased from 2.0 +/- 0.7 to 3.2 +/- 0.8 mm (P < 0.0001), with a mean increase of 73% +/- 62%. There was an inverse relationship between the MLD before and increase after the procedure (r = 0.75; P < 0.001). The BB diameter-to-MLD ratio before procedure was significantly associated with the increase in MLD (r = 0.70; P < 0.001). After the procedure, 18 of the 31 procedures were considered successful. In all successful procedures, the BB diameter was greater than twice the MLD before the procedure. Comparing children with Williams and Alagille syndrome with the remaining eight children, there were no significant differences in the increase in MLD. A small aneurysm and thrombus were noticed in two and three children, respectively, but no fatal complications were reported. BB angioplasty is effective for resistant peripheral pulmonary artery stenosis when conventional BA fails. The diameter of the BB should be larger than twice the minimal luminal diameter of the stenotic lesion.

    View details for DOI 10.1002/ccd.20030

    View details for PubMedID 15103608

  • Native right ventricular outflow stent implantation in patients with unsalvageable extracardiac conduits. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Veldtman, G. R., Sugiyama, H., Norgard, G., Mikailian, H., Lee, K. J., Benson, L. N. 2004; 61 (2): 256-8


    We describe two patients with unsalvageable ventricular-to-pulmonary artery conduits in whom endovascular stents were implanted in the native right ventricular (RV) outflow providing double outlet ventricle and RV hypertension relief. Both patients are free from surgical reintervention at 7 years and 5 months, respectively.

    View details for DOI 10.1002/ccd.10749

    View details for PubMedID 14755823

  • A prospective cohort study determining the prevalence of thrombotic events in children with acute lymphoblastic leukemia and a central venous line who are treated with L-asparaginase: results of the Prophylactic Antithrombin Replacement in Kids with Acute Lymphoblastic Leukemia Treated with Asparaginase (PARKAA) Study. Cancer Mitchell, L. G., Andrew, M., Hanna, K., Abshire, T., Halton, J., Anderson, R., Cherrick, I., Desai, S., Mahoney, D., McCuster, P., Wu, J., Dahl, G., Chait, P., de Veber, G., Lee, K. J., Mikulis, D., Ginsberg, J., Way, C. 2003; 97 (2): 508-16


    Thrombotic events (TEs) are serious secondary complications in children with acute lymphoblastic leukemia (ALL) who receive L-asparaginase (ASP) therapy; however, the prevalence of TEs has not been established. The primary objective of the Prophylactic Antithrombin Replacement in Kids with Acute Lymphoblastic Leukemia Treated with Asparaginase (PARKAA) Study was to determine the prevalence of TEs. The secondary objective was to detect any association of TEs with the presence of congenital or acquired prothrombotic disorders.Children with ALL were screened for TEs at the end of ASP treatment using bilateral venograms, ultrasound, magnetic resonance imaging, and echocardiography. Symptomatic TEs were confirmed by appropriate radiographic tests. All tests were read by a blinded central adjudication committee.Twenty-two of 60 children had TEs, a prevalence of 36.7% (95% confidence interval, 24.4-48.8%). TEs were located in the sinovenous system of the brain in 1 patient, the right atrium in 3 patients, and the upper central venous system in 19 patients. TEs detected by venography resulted in 1) 25-100% occlusion, with 1 in 3 patients showing occlusion of > 75% of the greatest vessel dimension, and 2) the presence of collaterals in 60% of patients, with 40% categorized as major. No children with TEs were positive for factor V Leiden or prothrombin gene 20201A, and four of eight children with antiphospholipid antibodies had a TE.The prevalence of TEs is exceedingly high in this population, and it is likely that the extent of occlusion is likely clinically significant. No trend was seen toward an association between TEs and the presence of congenital prothrombotic disorders. A trend was seen toward an association between TEs and antiphospholipid antibodies. Carefully designed clinical trials of primary prophylaxis for the prevention of TEs are required in this patient population.

    View details for DOI 10.1002/cncr.11042

    View details for PubMedID 12518376

  • Radiofrequency-assisted atrial septoplasty for an intact atrial septum in complex congenital heart disease. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions Du Marchie Sarvaas, G. J., Trivedi, K. R., Hornberger, L. K., Lee, K. J., Kirsh, J. A., Benson, L. N. 2002; 56 (3): 412-5


    Septoplasty of the atrial septum was performed with sequential balloon dilation following radiofrequency-assisted perforation of an intact atrial septum in two newborn infants with hypoplastic left heart syndrome and one with double-outlet right ventricle.

    View details for DOI 10.1002/ccd.10222

    View details for PubMedID 12112899

  • Evolving strategies and improving outcomes of the modified norwood procedure: a 10-year single-institution experience. The Annals of thoracic surgery Azakie, T., Merklinger, S. L., McCrindle, B. W., Van Arsdell, G. S., Lee, K. J., Benson, L. N., Coles, J. G., Williams, W. G. 2001; 72 (4): 1349-53


    This study reviews our 10-year experience with the modified Norwood procedure to determine its early and midterm outcomes. The focus is on the impact of evolving management strategies and accumulated institutional experience.A modified Norwood operation was performed in 171 infants over a 10-year period. Sixty-eight percent of the infants were male, the median age at operation was 6 days (range 1 to 175 days), and the median weight was 3.3 kg (range 1.7 to 4.8 kg). The 10-year period was divided into three eras: era I; 1990 through 1993; era II; 1994 through 1997; and era III; 1998 into 2000. Outcomes and risk factors for mortality were sought.Hypoplastic left heart syndrome or a variant was the primary diagnosis in 118 infants (69%). The overall 5-year survival rate was 43%. Multivariate analysis revealed that only need of preoperative ventilatory support, earlier date of operation, and lower weight at operation were significant independent predictors of increased time-related mortality. Morphologic features such as a diagnosis other than hypoplastic left heart syndrome, ascending aortic size, and noncardiac anomalies were not significantly associated with an increased risk of death. The hospital survival rate for stage-one palliation in era III was 82%, significantly better than that in the preceding eras (p < 0.001). Attrition between stages one and two accounted for a 15% mortality rate among hospital survivors.With increasing experience and improvements in perioperative care and surgical technique, good outcomes can be expected for the first-stage modified Norwood procedure. Greater monitoring of patients in the interstage period may reduce interval mortality and improve overall survival.

    View details for DOI 10.1016/s0003-4975(01)02795-3

    View details for PubMedID 11603459

  • Restoration of aortopulmonary shunt patency. The American journal of cardiology Lee, K. J., Humpl, T., Hashmi, A., Nykanen, D. G., Williams, W. G., Benson, L. N. 2001; 88 (3): 325-8

    View details for DOI 10.1016/s0002-9149(01)01654-x

    View details for PubMedID 11472721

  • Exercise capacity after repair of Tetralogy of Fallot in infancy. The American journal of cardiology Yetman, A. T., Lee, K. J., Hamilton, R., Morrow, W. R., McCrindle, B. W. 2001; 87 (8): 1021-3; A5

    View details for DOI 10.1016/s0002-9149(01)01443-6

    View details for PubMedID 11306001

  • Pediatric heart transplantation: improving results in high-risk patients. The Journal of thoracic and cardiovascular surgery Dellgren, G., Koirala, B., Sakopoulus, A., Botta, A., Joseph, J., Benson, L., McCrindle, B., Dipchand, A., Cardella, C., Lee, K. J., West, L., Poirier, N., Van Arsdell, G. S., Williams, W. G., Coles, J. G. 2001; 121 (4): 782-91


    Our institutional experience with 73 pediatric patients undergoing cardiac transplantation between January 1, 1990, and December 31, 1999, was reviewed to determine the impact of unconventional donor and recipient management protocols implemented to extend the availability of this therapy.The introduction of donor blood cardioplegic solution with added insulin was associated with a significant improvement in patient and graft survival (hazard ratio [Cox] = 0.25, P =.08), despite significantly longer ischemic times with this protocol compared with the use of crystalloid-based donor procurement techniques (P <.01). Eleven patients underwent intentional transplantation of ABO-incompatible donor hearts with the aid of a protocol of plasma exchange on bypass. In this subgroup, there were 2 early deaths caused by nonspecific graft failure (n = 1) and respiratory complications with mild vascular rejection (n = 1), and there was 1 late death caused by lymphoma. ABO-incompatible transplantation was not a risk factor for death by multivariate analysis. The postoperative course in these patients suggests minimal reactivity directed against incompatible grafts on the basis of low anti-donor blood group antibody production, in association with a favorable rejection profile. Ten of 13 patients requiring preoperative support with an extracorporeal membrane oxygenator survived transplantation; there were 3 additional late deaths in this subgroup (hazard ratio = 2.88, P =.05).The results with pediatric cardiac transplantation continue to improve as a result of changes in both surgical and medical protocols permitting successful treatment of patients conventionally considered at high risk or unsuitable for transplantation.

    View details for DOI 10.1067/mtc.2001.111383

    View details for PubMedID 11279421

  • ABO-incompatible heart transplantation in infants. The New England journal of medicine West, L. J., Pollock-Barziv, S. M., Dipchand, A. I., Lee, K. J., Cardella, C. J., Benson, L. N., Rebeyka, I. M., Coles, J. G. 2001; 344 (11): 793-800


    Transplantation of hearts from ABO-incompatible donors is contraindicated because of the risk of hyperacute rejection mediated by preformed antibodies in the recipient to blood-group antigens of the donor. This contraindication may not apply to newborn infants, who do not yet produce antibodies to T-cell-independent antigens, including the major blood-group antigens.We studied 10 infants 4 hours to 14 months old (median, 2 months) who had congenital heart disease or cardiomyopathy and who received heart transplants from donors of incompatible blood type between 1996 and 2000. Serum isohemagglutinin titers were measured before and after transplantation. Plasma exchange was performed during cardiopulmonary bypass; no other procedures for the removal of antibodies were used. Standard immunosuppressive therapy was given, and rejection was monitored by means of endomyocardial biopsy. The results were compared with those in 10 infants who received heart transplants from ABO-compatible donors.The overall survival rate among the 10 recipients with ABO-incompatible donors was 80 percent, with 2 early deaths due to causes presumed to be unrelated to ABO incompatibility. The duration of follow-up ranged from 11 months to 4.6 years. Two infants had serum antibodies to antigens of the donor's blood group before transplantation. No hyperacute rejection occurred; mild humoral rejection was noted at autopsy in one of the infants with antibodies. No morbidity attributable to ABO incompatibility has been observed. Despite the eventual development of antibodies to antigens of the donor's blood group in two infants, no damage to the graft has occurred. Because of the use of ABO-incompatible donors, the mortality rate among infants on the waiting list declined from 58 percent to 7 percent.ABO-incompatible heart transplantation can be performed safely during infancy before the onset of isohemagglutinin production; this technique thus contributes to a marked reduction in mortality among infants on the waiting list.

    View details for DOI 10.1056/NEJM200103153441102

    View details for PubMedID 11248154

  • Graft accommodation in infant recipients of ABO-incompatible heart transplants: donor ABH antigen expression in graft biopsies. The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation West, L. J., Pollock-Barziv, S. M., Lee, K. J., Dipchand, A. I., Coles, J. G., Ruiz, P. 2001; 20 (2): 222

    View details for DOI 10.1016/s1053-2498(00)00488-5

    View details for PubMedID 11250415

  • Dobutamine/atropine stress echocardiography: feasibility, safety and early results in paediatric heart transplant recipients. The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation Dipchand, A. I., Mccrindle, B. W., Lee, K., West, L. J., Smallhorn, J. F. 2001; 20 (2): 232

    View details for DOI 10.1016/s1053-2498(00)00517-9

    View details for PubMedID 11250446

  • Comparison of two transcatheter closure methods of persistently patent arterial duct. The American journal of cardiology Justino, H., Justo, R. N., Ovaert, C., Magee, A., Lee, K. J., Hashmi, A., Nykanen, D. G., McCrindle, B. W., Freedom, R. M., Benson, L. N. 2001; 87 (1): 76-81


    A randomized trial of arterial duct occlusion with a double umbrella (DU) or wire coil (WC) was undertaken for patients <18 years of age, weighing >10 kg with isolated ducts < or = 3 mm in diameter. Baseline, procedural, and outcome characteristics were compared in an intention-to-treat analysis according to randomization group. From 40 consecutively screened patients, 2 were not enrolled due to a ductal diameter of >3 mm on initial aortography, 38 patients were randomized to either the DU (n = 20) or WC (n = 18) groups. The groups did not differ significantly with respect to age, weight, gender, duct size, type, or branch pulmonary artery diameters. Crossover occurred only in the DU group, where 4 patients (20%) had a ductal diameter of < or = 1 mm and could not be entered for umbrella placement. All remaining DU group patients had ductal diameters of > or = 1.3 mm (p <0.0001). There were no embolizations or secondary implants in the DU group, but in the WC group there was 1 early and 1 late embolization, with 6 patients (33%) with > or = 2 coils. Mean times for the procedure (DU 68+/-19 minutes; WC 65+/-27 minutes; p = 0.70) and fluoroscopy (DU 14+/-4 minutes; WC 11+/-6 minutes; p = 0.22) did not differ significantly. Angiographic duct closure was documented in 4 of 13 patients (31%) of the DU group and 4 of 18 patients (22%) of the WC group (p = 0.69). Combined with an echocardiogram, closure in 11 of 17 patients with DU (65%) and 13 of 18 patients with WC (72%) (p = 0.64) was documented before hospital discharge. One WC group patient received thrombolytic therapy for a femoral artery thrombus. Follow-up at a median of 6.5 months (range 3.2 to 37) showed closure by Doppler echocardiography in 15 of 19 patients with DU (79%) versus 14 of 18 patients with WC (78%) (p = 1.0). Thus, with a tendency toward similar procedural characteristics and outcomes, the higher cost of the DU system compared with coil implants favors the use of coils for closure of the small arterial duct.

    View details for DOI 10.1016/s0002-9149(00)01276-5

    View details for PubMedID 11137838

  • Transcatheter closure of atrial septal defects using the Cardio-Seal implant. Heart (British Cardiac Society) Pedra, C. A., Pihkala, J., Lee, K. J., Boutin, C., Nykanen, D. G., McLaughlin, P. R., Harrison, D. A., Freedom, R. M., Benson, L. 2000; 84 (3): 320-6


    To review the outcomes of transcatheter closure of atrial septal defects using the Cardio-Seal implant.A prospective interventional study.Tertiary referral centre.The first 50 patients (median age 9.7 years) who underwent attempted percutaneous occlusion.Procedures were done under general anaesthesia and transoesophageal guidance between December 1996 and July 1998.Success of deployment, complications, and assessment of right ventricular end diastolic diameter, septal wall motion, and occlusion status by echocardiography.The median balloon stretched diameter was 14 mm. Multiple atrial septal defects were present in 11 patients (22%) and a deficient atrial rim (< 4 mm) in 19 (38%). In four patients (8%), a second device was implanted after removal of an initially malpositioned first implant. There were no significant immediate complications. All patients except one were discharged within 24 hours. At the latest follow up (mean 9.9 months) a small shunt was present in 23 patients (46%), although right ventricular end diastolic dimensions (mean (SD)) corrected for age decreased from 137 (29)% to 105 (17)% of normal, and septal motion abnormalities normalised in all but one patient. No predictors for a residual shunt were identified. Supporting arm fractures were detected in seven patients (14%) and protrusion of one arm through the defect in 16 (32%), the latter being more common in those with smaller anterosuperior rims. No untoward effects resulted from arm fractures or protrusion. There were no complications during follow up, although five patients (10%) experienced transient headaches.The implantation of the Cardio-Seal device corrects the haemodynamic disturbances secondary to the right ventricular volume overload, with good early outcome.

    View details for DOI 10.1136/heart.84.3.320

    View details for PubMedID 10956299

    View details for PubMedCentralID PMC1760951

  • Interventions associated with minimal fontan mortality. The Annals of thoracic surgery Van Arsdell, G. S., McCrindle, B. W., Einarson, K. D., Lee, K. J., Oag, E., Caldarone, C. A., Williams, W. G. 2000; 70 (2): 568-74


    The operative mortality rate for the first 400 Fontan procedures at this institution was 15% but declined to 4% for the next 100 procedures.The cases of 100 consecutive patients receiving the Fontan procedure and associated with this change in mortality rate were reviewed to determine associations.The mortality rate in the first and second 50 patients was 16% and 0%, respectively. There were no differences in age, number of risk factors, diagnosis, or operating surgeon between the two groups. Patients in the lower-mortality era were significantly more likely to have had a cavopulmonary anastomosis before a Fontan procedure (90% versus 70%) and to have an extracardiac Fontan procedure (38% versus 8%), shorter cross-clamp (45+/-24 minutes versus 58+/-22 minutes) and cardiopulmonary bypass times (121+/-42 minutes versus 141+/-45 minutes), magnesium-rich cardioplegia (100% versus 39%), hemoconcentration after bypass (67% versus 4%), and institution of pharmacologic support in the operating room.Patient characteristics and risk factors were similar in the two groups. However, several interventions that were increasingly utilized in the lower-mortality era, including the extracardiac Fontan procedure and modified ultrafiltration after bypass, are associated with lower mortality. Each one had the potential to improve postoperative myocardial function.

    View details for DOI 10.1016/s0003-4975(00)01438-7

    View details for PubMedID 10969682

  • Microcephaly-cardiomyopathy syndrome: confirmation of the phenotype. Journal of medical genetics Kennedy, S. J., Lee, K. J., McCrindle, B. W., Teebi, A. S. 1999; 36 (11): 854-5


    We report a 9 year old girl with microcephaly and self-limiting dilated cardiomyopathy. Additional features include mental retardation, delayed developmental milestones, and minor dysmorphic features. This is the second reported case of this phenotype, which is believed to be a new autosomal recessive syndrome.

    View details for PubMedID 10544231

    View details for PubMedCentralID PMC1734265

  • Clinical outcomes of acute myocarditis in childhood. Heart (British Cardiac Society) Lee, K. J., McCrindle, B. W., Bohn, D. J., Wilson, G. J., Taylor, G. P., Freedom, R. M., Smallhorn, J. F., Benson, L. N. 1999; 82 (2): 226-33


    To describe clinical outcomes of a paediatric population with histologically confirmed lymphocytic myocarditis.A retrospective review between November 1984 and February 1998.A major paediatric tertiary care hospital.36 patients with histologically confirmed lymphocytic myocarditis.Survival, cardiac transplantation, recovery of ventricular function, and persistence of dysrhythmias.Freedom from death or cardiac transplantation was 86% at one month and 79% after two years. Five deaths occurred within 72 hours of admission, and one late death at 1.9 years. Extracorporeal membrane oxygenation support was used in four patients, and three patients underwent heart replacement. 34 patients were treated with intravenous corticosteroids. In the survivor/non-cardiac transplantation group (n = 29), the median follow up was 19 months (range 1.2-131.6 months), and the median period for recovery of a left ventricular ejection fraction to > 55% was 2.8 months (range 0-28 months). The mean (SD) final left ventricular ejection and shortening fractions were 66 (9)% and 34 (8)%, respectively. Two patients had residual ventricular dysfunction. No patient required antiarrhythmic treatment. All survivors reported no cardiac symptoms or restrictions in physical activity.Our experience documents good outcomes in paediatric patients presenting with acute heart failure secondary to acute lymphocytic myocarditis treated with immunosuppression. Excellent survival and recovery of ventricular function, with the absence of significant arrhythmias, continued cardiac medications, or restrictions in physical activity were the normal outcomes.

    View details for DOI 10.1136/hrt.82.2.226

    View details for PubMedID 10409542

    View details for PubMedCentralID PMC1729152