Andrew Michael Brennan Jr

All Publications

• Diastolic Function Unchanged After Lifestyle Intervention Despite Improved VO2 in Pediatric Heart Transplant Patients. Pediatric cardiology Brennan, A., Mardy, C., Punn, R., Tierney, S. 2026

  Abstract

  Pediatric heart transplant recipients commonly exhibit diastolic dysfunction, which may contribute to reduced exercise capacity. In our Healthy Hearts study, a supervised exercise and nutrition intervention improved exercise performance and endothelial function. We hypothesized that this intervention would also improve resting echocardiographic markers of diastolic function in this cohort. Fourteen stable heart transplant patients aged 8 to 19 years, at least one year post-transplant, participated in a live-video-supervised exercise and nutrition intervention from 2014 to 2018. Participants completed a 12-16-week intervention, followed by a maintenance phase of similar duration with mostly self-directed sessions. Echocardiograms taken near baseline, post-intervention, and post-maintenance visits were reviewed retrospectively. Diastolic dysfunction at baseline was defined by any of the following: E/A ratio > 2, mitral deceleration time < 160 ms, septal or lateral E/e' > 14, or tricuspid regurgitant jet velocity > 2.8 m/s. Atrial strain was measured using TOMTEC software. No significant improvements from baseline to post-intervention were observed in conventional diastolic function parameters or atrial strain, including patients with baseline diastolic dysfunction (n = 9). Among those with baseline diastolic dysfunction, there was a strong inverse correlation between the change in E/A ratio and the change in peak VO2 from baseline to post-intervention (r = - 0.94). Despite improvements in exercise capacity and endothelial function following a nutrition and exercise intervention in pediatric heart transplant patients, echocardiographic markers of diastolic function remained unchanged. These findings suggest that peripheral rather than cardiac adaptations may underlie the observed functional improvements.

  View details for DOI 10.1007/s00246-026-04213-3

  View details for PubMedID 41843013

  View details for PubMedCentralID 12414510

• Left Atrial Mechanics in Isolated Total Anomalous Pulmonary Venous Connection After Repair. Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography Brennan, A., Tierney, S., Thorson, K., Ma, M., Ho, D. Y., Martin, E., Punn, R. 2025

  Abstract

  Repaired total anomalous pulmonary venous connection (TAPVC) patients with preoperative pulmonary venous obstruction (PVO) have reductions in echocardiographic metrics, such as left atrial reservoir function and pulmonary venous variability index (PVVI). We hypothesized reduced preoperative left atrial strain mechanics in isolated TAPVC patients serve as risk factors for postoperative PVO. We also evaluated echocardiographic metrics and clinical characteristics associated with preoperative and postoperative PVO, as well as compared these to healthy controls.A single-center retrospective study was conducted on 64 isolated TAPVC patients who underwent repair between 9/1/2003 and 12/31/2022 with an available preoperative, immediate postoperative, and follow-up echocardiogram (most recent or prior to reintervention). Twenty-five individual age and body surface area-matched healthy controls were compared at each echo time point. LA strain analysis was performed using TOMTEC software. Postoperative PVO was defined as peak Doppler velocity ≥1.2 m/s in an individual pulmonary vein or pulmonary venous confluence.Thirty-seven (58%) TAPVC patients had preoperative PVO. Twenty-eight (44%) patients developed postoperative PVO, of which twelve (19%) required reintervention. Preoperative PVO increased the risk of postoperative PVO (78.6% vs 41.7%, p = 0.004) and reintervention (91.7% vs 50%, p = 0.001). This was no longer true when preoperative PVO was defined as peak velocity ≥1.2 m/s (p = 0.2362), although it remained associated with reintervention (p = 0.02). In TAPVC patients there were no other preoperative echocardiographic metrics, including LA strain measurements and PVVI, significantly associated with postoperative PVO or reintervention. Immediately postoperative LA volumes and mechanics demonstrated no difference between TAPVC patients with and without postoperative PVO or reintervention. Compared to healthy controls, pulmonary vein Doppler absolute velocities, left ventricle length, and LA mechanics were diminished in TAPVC patients at all echo time points (p = 0.0149 to <0.0001). In contrast LA two-dimensional volumes, left ventricular volumes, and LA dyssynchrony index normalized over time.Although preoperative pulmonary vein Doppler velocity ≥ 1.2 m/s increased the risk for reintervention in repaired isolated TAPVC patients, no preoperative LA mechanics or other echocardiographic metrics were associated with the development of postoperative PVO or reintervention. Immediately postoperative LA volumes do not appear to modify reintervention risk indicating pulmonary vein hypoplasia/stenosis is the primary driver for reintervention. Despite ongoing impaired LA mechanics and decreased LV length, LA and LV volumes normalize over time in repaired TAPVC patients.

  View details for DOI 10.1016/j.echo.2025.08.021

  View details for PubMedID 40915397

• Association Between Location of Pulmonary Outflow Obstruction and Right Ventricular Size and Function After Repair of Tetralogy of Fallot, Pulmonary Atresia, and Major Aortopulmonary Collaterals. Pediatric cardiology Brennan, A., Punn, R., Lopez, L., Long, Z., McElhinney, D. B., Mainwaring, R. D., Ma, M., Friedberg, M. K., Hanley, F. L., Arunamata, A. A. 2024

  Abstract

  Quantification of right ventricular (RV) size and function after tetralogy of Fallot repair is critical for determining timing of reintervention and outcomes. Tetralogy of Fallot patients with pulmonary atresia and major aortopulmonary collateral arteries (TOF/PA/MAPCAs) are a unique group in which the RV is subjected to various loading conditions, allowing for direct comparison. Retrospective evaluation of RV echocardiographic indices in repaired pediatric TOF/PA/MAPCAs patients (2/2002 - 4/2018). Patients were categorized as having conduit stenosis (peak gradient ≥ 2.5 m/s) and/or distal pulmonary artery (PA) stenoses (requiring catheter or surgical intervention and > 1/2 systemic RV pressures). A comparison group (N = 9) included distinct age-matched repaired patients without residual lesions. Indexed right heart dimensions were larger in patients with distal PA stenoses (N = 49) compared to conduit stenosis (N = 26), including RV end-diastolic and end-systolic dimensions (p < 0.01), despite earlier time to reintervention (p < 0.0001). RV fractional area change (FAC) was diminished in patients with distal PA stenoses compared to patients without residual lesions (p = 0.006). Patients with conduit stenosis demonstrated a marked decrement in tricuspid annular plane systolic excursion (TAPSE) z-scores. Repaired TOF/PA/MAPCAs patients with residual distal PA stenoses have larger right heart dimensions compared to patients with conduit stenosis, and decreased RV FAC compared to patients without residual lesions at 1-2 years after repair, suggesting early surveillance and immediate intervention on stenotic PA segments appears warranted to decrease the risk of further deterioration of RV systolic function.

  View details for DOI 10.1007/s00246-024-03730-3

  View details for PubMedID 39680069

  View details for PubMedCentralID 3898939

• Anti-NMDAR Encephalitis: A Multidisciplinary Approach to Identification of the Disorder and Management of Psychiatric Symptoms. Psychosomatics Forrester, A., Latorre, S., O'Dea, P. K., Robinson, C., Goldwaser, E. L., Trenton, A., Tobia, A., Aziz, R., Dhawan, S., Brennan, A., Kurukumbi, M., Dong, Y., Benavides, D. R., Offurum, A. I. 2020; 61 (5): 456-466

  Abstract

  The novelty of anti-NMDA receptor encephalitis, for which somatic treatments have only recently been developed, has led to a lack of information on assessment and treatment of its variable behavioral manifestations.In this article, we discuss 4 challenging cases of anti-NMDAR encephalitis, focusing on the importance of a multidisciplinary approach to identification and management of the disorder and the necessity of close collaboration in the acute hospital setting for management of the behavioral symptoms.The cases we discuss highlight some of the medication and nonpharmacologic treatment strategies that may facilitate management of psychiatric symptoms, both while the medical workup is ongoing and after the diagnosis has been confirmed.

  View details for DOI 10.1016/j.psym.2020.04.017

  View details for PubMedID 32507506

• A Method to Account for Variation in Congenital Heart Surgery Length of Stay. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies Brennan, A., Gauvreau, K., Connor, J., Almodovar, M., DiNardo, J., Banka, P., Nathan, M., Mathieu, D., Kaza, A., Mayer, J. E., Bergersen, L. 2017; 18 (6): 550-560

  Abstract

  We sought to develop a risk-adjustment methodology for length of stay in congenital heart surgery, as none exist.Prospective cohort analysis combined with previously obtained retrospective cohort analysis of a Department of Cardiovascular Surgery clinical database.Patients discharged from Boston Children's Hospital between October 1, 2006, and May 31, 2014, that underwent a congenital heart surgery procedure(s) linked to one of 103 surgical procedure types.Six thousand two hundred nine discharges during the reporting period at Boston Children's Hospital comprised the cohort. Seven Surgical Length Categories were developed to group surgical procedure types. A multivariable model for outcome length of stay was built using a derivation cohort consisting of a 75% random sample, starting with Surgical Length Categories and considering additional a priori factors. Postoperative factors were then added to improve predictive performance. The remaining 25% of the cohort was used to validate the multivariable models. The coefficient of determination (R) was used to estimate the variability in length of stay explained by each factor. The Surgical Length Categories yielded an R of 42%. Model performance increased when the a priori factors preoperative status, noncardiac abnormality, genetic anomaly, preoperative catheterization during episode of care, weight less than 3 kg, and preoperative vasoactive support medication were introduced to the model (R = 60.8%). Model performance further improved when postoperative ventilation greater than 7 days, operating room time, postoperative catheterization during episode of care, postoperative reintubation, number of postoperative vasoactive support medications, postoperative ICU infection, and greater than or equal to one secondary surgical procedure were added (R = 76.7%). The validation cohort yielded an R of 76.5%.We developed a statistically valid procedure-based categorical variable and multivariable model for length of stay of congenital heart surgeries. The Surgical Length Categories and important a priori and postoperative factors may be used to pursue a predictive tool for length of stay to inform scheduling and bed management practices.

  View details for DOI 10.1097/PCC.0000000000001168

  View details for PubMedID 28437365

• A method to account for variation in congenital heart surgery charges. The Annals of thoracic surgery Bergersen, L., Brennan, A., Gauvreau, K., Connor, J., Almodovar, M., DiNardo, J., David, S., Triedman, J., Banka, P., Emani, S., Mayer, J. E. 2015; 99 (3): 939-46

  Abstract

  In response to societal pressure to reduce expenditures and increase quality, we sought to develop a methodology to predict hospital charges related to congenital heart surgery.Patients undergoing congenital heart surgery at Boston Children's Hospital in fiscal years 2007 to 2009 comprised the derivation cohort. Clinical data, including Current Procedural Terminology coding of the primary surgical intervention, were collected prospectively and linked to total hospital charges for an episode of care. Surgical charge categories were developed to group surgical procedure types using empiric data and expert consensus. A multivariable model was built using surgical charge categories and additional patient and procedural characteristics to predict the outcome, total hospital charges. A contemporary cohort for fiscal years 2010 to 2012 was used to validate surgical charge categories and the multivariable model.In the derivation cohort, 2,105 cases met inclusion criteria. One hundred three surgical procedure types were categorized into seven surgical charge categories, yielding a grouper variable with an R(2) explanatory value of 47.3%. Explanatory value increased with consideration of patient age, admission status, and preoperative ventilator dependence (R(2) = 59.4%), as well as weight category, noncardiac abnormality, and genetic syndrome other than trisomy 21 (R(2) = 61.5%). Additional variability in charge was explained when extracorporeal membrane oxygenation utilization and greater than one operating room visit during the episode of care were added (R(2) = 74.3%). The contemporary cohort yielded an R(2) explanatory value of 67.7%.The combination of clinical data with resource utilization information resulted in a statistically valid predictive model for total hospital charges in congenital heart surgery.

  View details for DOI 10.1016/j.athoracsur.2014.10.066

  View details for PubMedID 25620593

• Development of a charge adjustment model for cardiac catheterization. Pediatric cardiology Brennan, A., Gauvreau, K., Connor, J., O'Connell, C., David, S., Almodovar, M., DiNardo, J., Banka, P., Mayer, J. E., Marshall, A. C., Bergersen, L. 2015; 36 (2): 264-73

  Abstract

  A methodology that would allow for comparison of charges across institutions has not been developed for catheterization in congenital heart disease. A single institution catheterization database with prospectively collected case characteristics was linked to hospital charges related and limited to an episode of care in the catheterization laboratory for fiscal years 2008-2010. Catheterization charge categories (CCC) were developed to group types of catheterization procedures using a combination of empiric data and expert consensus. A multivariable model with outcome charges was created using CCC and additional patient and procedural characteristics. In 3 fiscal years, 3,839 cases were available for analysis. Forty catheterization procedure types were categorized into 7 CCC yielding a grouper variable with an R (2) explanatory value of 72.6%. In the final CCC, the largest proportion of cases was in CCC 2 (34%), which included diagnostic cases without intervention. Biopsy cases were isolated in CCC 1 (12%), and percutaneous pulmonary valve placement alone made up CCC 7 (2%). The final model included CCC, number of interventions, and cardiac diagnosis (R (2) = 74.2%). Additionally, current financial metrics such as APR-DRG severity of illness and case mix index demonstrated a lack of correlation with CCC. We have developed a catheterization procedure type financial grouper that accounts for the diverse case population encountered in catheterization for congenital heart disease. CCC and our multivariable model could be used to understand financial characteristics of a population at a single point in time, longitudinally, and to compare populations.

  View details for DOI 10.1007/s00246-014-0994-3

  View details for PubMedID 25113520

  View details for PubMedCentralID PMC4303716