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Dive into the research topics where Sowmya Balasubramanian is active.

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Featured researches published by Sowmya Balasubramanian.


Circulation-cardiovascular Interventions | 2012

Outcomes After Stent Implantation for the Treatment of Congenital and Postoperative Pulmonary Vein Stenosis in Children

Sowmya Balasubramanian; Audrey C. Marshall; Kimberlee Gauvreau; Lynn F. Peng; Alan Nugent; James E. Lock; Doff B. McElhinney

Background— Pulmonary vein stenosis (PVS) is a rare condition that can lead to worsening pulmonary hypertension and cardiac failure in children, and it is frequently lethal. Surgical and transcatheter approaches are acutely successful but restenosis is common and rapid. Methods and Results— We reviewed outcomes among patients who underwent transcatheter pulmonary vein stent implantation for congenital or postoperative PVS at <18 years of age. A total of 74 pulmonary veins were stented with bare metal, drug-eluting, or covered stents in 47 patients. Primary diagnoses included PVS associated with anomalous venous return in 51%, PVS associated with other congenital cardiovascular defects in 36%, and congenital (“de novo”) PVS in 13% of patients. Median age at the time of pulmonary vein stent implantation was 1.4 years. During a median cross-sectional follow-up of 3.1 years, 21 patients died. Estimated survival was 62±8% at 1 year and 50±8% at 5 years after pulmonary vein stent implantation. Stent placement acutely relieved focal obstruction in all veins. Of the 54 stents reexamined with catheterization, 32 underwent reintervention. Freedom from reintervention was 62±7% at 6 months and 42±7% at 1 year. Stent occlusion was documented in 9 cases and significant in-stent stenosis in 17 cases. Stent implantation diameter ≥7 mm was associated with longer freedom from reintervention (hazard ratio, 0.32; P=0.015) and from significant in-stent stenosis (hazard ratio, 0.14; P=0.002). Major acute complications occurred in 5 cases. Conclusions— Transcatheter stent implantation can acutely relieve PVS in children, but reintervention is common. Larger stent lumen size at implantation is associated with longer stent patency and a lower risk of reintervention.


American Journal of Cardiology | 2014

In-Hospital Arrhythmia Development and Outcomes in Pediatric Patients With Acute Myocarditis

Christina Y. Miyake; Sarah A. Teele; Liyuan Chen; Kara S. Motonaga; Anne M. Dubin; Sowmya Balasubramanian; Raymond R. Balise; David N. Rosenthal; Mark E. Alexander; Edward P. Walsh; Douglas Y. Mah

Cardiac arrhythmias are a complication of myocarditis. There are no large studies of in-hospital arrhythmia development and outcomes in pediatric patients with acute myocarditis. This was a retrospective 2-center review of patients ≤21 years hospitalized with acute myocarditis from 1996 to 2012. Fulminant myocarditis was defined as the need for inotropic support within 24 hours of presentation. Acute arrhythmias occurred at presentation and subacute after admission. Eighty-five patients (59% men) presented at a median age of 10 years (1 day to 18 years). Arrhythmias occurred in 38 patients (45%): 16 acute, 12 subacute, and 9 acute and subacute (1 onset unknown). Arrhythmias were associated with low voltages on the electrocardiogram (14 of 34, 41% vs 6 of 47, 13%; odds ratio [OR] 4.78, 95% confidence interval [CI] 1.60 to 14.31) and worse outcome (mechanical support, orthotopic heart transplant, or death; OR 7.59, 95% CI 2.61 to 22.07) but were not statistically significantly associated with a fulminant course, ST changes, initial myocardial function, lactate, creatinine level, C-reactive protein and/or erythrocyte sedimentation rate, or troponin I level, after adjusting for multiple comparisons. Subacute arrhythmias were associated with preceding ST changes (10 of 15, 67% vs 15 of 59, 25%, OR 5.87, 95% CI 1.73 to 19.93). All patients surviving to discharge had arrhythmia resolution or control before discharge (10 on antiarrhythmic), with 1 exception (patient with complete heart block requiring a pacemaker). At 1-year follow-up, there were 3 recurrences of ventricular arrhythmias, but no arrhythmia-related mortality. In conclusion, arrhythmias are common in pediatric patients with myocarditis, occurring in nearly 1/2 of all hospitalized children and are associated with a worse outcome. Early identification of subacute arrhythmias using electrocardiographic changes may help management. A majority of patients do not require continued postdischarge arrhythmia treatment.


Congenital Heart Disease | 2012

Bilateral Disease and Early Age at Presentation Are Associated with Shorter Survival in Patients with Congenital Heart Disease and Intraluminal Pulmonary Vein Stenosis

Sowmya Balasubramanian; Maliha Rehman; Kimberlee Gauvreau; Kathy J. Jenkins

PURPOSE Pulmonary vein stenosis (PVS) is a progressive disease that is frequently lethal. We have previously identified neoproliferation of myofibroblasts as the mechanism for progressive intraluminal PVS. PVS occurs in association with other congenital heart diseases (CHD) and in structurally normal hearts. This study sought to describe the spectrum of CHD seen with PVS and explore risk factors associated with mortality. METHODS All patients diagnosed over a 12-year period with a combination of PVS involving ≥2 vessels and CHD were identified. Cases were categorized according to major anatomic and physiologic categories. Patient and disease characteristics associated with time to death were explored. RESULTS Eighty-two cases followed longitudinally at our institution were analyzed. Anatomic diagnoses included nonheterotaxy + anomalous pulmonary venous return (29%), heterotaxy + anomalous veins (20%), two ventricles + normal veins (22%), and single ventricle + normal veins (29%). Median age at diagnosis was 5.3 months (0-24 years). Despite multiple treatments, there were 35 (43%) deaths in the group with an estimated survival of 71%, 64%, and 44% at 1, 2, and 5 years, respectively. Bilateral disease at diagnosis (hazard ratio [HR] 3.9 [1.7, 9.2], P= .002), age <5 months at diagnosis (HR 3.4 [1.6, 7.6], P= .002), and involvement of >2 pulmonary veins at diagnosis (HR 3.7 [1.6, 8.8], P= .003) were associated with shorter time to death in univariate analysis. In multivariable analysis, both bilateral disease (HR 2.9 [1.2, 7.1]P= .02) and age <5 months at diagnosis (HR 2.4 [1.1, 5.6]P= .03) were independently associated with time to death. CONCLUSION Bilateral disease and earlier age at diagnosis are independent predictors of poor survival in patients with CHD and PVS, while patients with unilateral disease presenting at an older age have a better prognosis. These findings are helpful in risk stratification of patients with CHD and multivessel PVS.


Cardiovascular Engineering and Technology | 2013

Functional Imaging in Fetal Echocardiography: A Review of Conventional and Novel Approaches

Sowmya Balasubramanian; Theresa A. Tacy

Advances in fetal cardiac imaging have resulted in changes in the practice of fetal cardiology, and in improved neonatal outcomes for these patients. As the anatomic diagnostic accuracy of fetal cardiology has improved, cardiologists have sought new challenges in fetal imaging, and with new emphasis on improved front line detection, treatment/intervention during fetal life, and assessment of fetal ventricular function and cardiovascular performance. The evolution of noninvasive assessment of fetal cardiac function is related to technologic advances in ultrasound imaging. This article reviews conventional methods of the assessment of cardiac function, as well as some promising directions for future evaluation with emphasis on future applications of 3D echocardiography and 3D speckle tracking echocardiography.


Congenital Heart Disease | 2014

Chest Radiographic Findings in Pediatric Patients with Intraluminal Pulmonary Vein Stenosis

Caitlin E. Mayhew; Edward Y. Lee; Sowmya Balasubramanian; Muhammad Muneeb; Kimberlee Gauvreau; Donald A. Tracy; Kathy J. Jenkins

UNLABELLED Early recognition of pulmonary vein stenosis (PVS) is crucial for optimizing clinical outcomes. Our goal was to characterize radiographic patterns specific to pediatric patients with PVS to facilitate early detection. PATIENTS AND METHODS Pediatric patients with multivessel (≥2) intraluminal PVS were identified from a single-center registry. Initial chest radiographs were reviewed. Radiographic findings were summarized using frequencies and percentages for categorical data, and medians and ranges for continuous data. Interrater agreement was assessed using kappa statistics. RESULTS Chest radiographs of 41 PVS patients were evaluated; median age at presentation 5.2 (0.5-102.6) months. Underlying congenital heart disease was present in 31 (76%), lung disease in four (10%), and neither in six (15%). Common heart diseases were hypoplastic left heart syndrome (five, 12%), totally anomalous pulmonary venous connection (nine, 22%), and heterotaxy (five, 12%). PVS was bilateral in 22 (54%), right-sided in six (14%), and left-sided in 13 (32%). All chest radiographs were abnormal. Increased interstitial opacity was present in all patients, reticular opacity in 35 (85%), and ground-glass opacity in 29 (71%). Consolidation (one, 2%), pleural effusions (four, 10%), and nodular opacities (0) were unusual. Distributional heterogeneity was common (17, 42%). Interrater agreement was generally high (kappa >0.84) except for lobe location. Findings were similar among patients with isolated PVS, PVS with congenital heart disease, and PVS with lung disease. CONCLUSION Diagnosis of PVS should be considered in infants with increased interstitial opacity, reticular opacity, and ground-glass opacity on chest radiography, especially if findings are heterogeneous.


Congenital Heart Disease | 2014

Midgestation fetal pulmonary annulus size is predictive of outcome in tetralogy of fallot.

Kevin G. Friedman; Sowmya Balasubramanian; Wayne Tworetzky

BACKGROUND Surgical management of tetralogy of Fallot (TOF) is increasingly moving toward valve-sparing approaches rather than transannular patch (TAP). We evaluate whether fetal pulmonary valve (PV) size is predictive of postnatal course and surgical approach in TOF. METHODS In this retrospective study, fetal and postnatal demographic, clinical, and echocardiographic data on 66 patients diagnosed prenatally with TOF were collected. We compared those with midgestation PV z-score > -3.5 to those with z-score ≤-3.5. We analyzed fetal and postnatal PV size and growth and outcomes between groups RESULTS Gestational age at first fetal echo was 23 weeks (range 18-28). PV diameter and z-score on midgestation echo were 3.5 mm (1.3-6.0) and -2.8 (-0.5 to -6.0) respectively. Patients with PV z-score ≤ -3.5 on first fetal echo had smaller PV diameter (4.5 vs. 5.0 mm, P = .047) and PV z-score (-3.8 vs. -2.8, P < .001) in late gestation and at time of surgery (6.0 mm vs. 7.0 mm, P = .01; z-score = -2.9 vs. -1.7, P = .007). Similarly, those with smaller fetal PV z-score had smaller main and branch pulmonary arteries at time of surgery. PV growth rate over gestation was similar between groups, while after-birth PV growth rate was lower in those with smaller PV (0 mm/month vs. 0.6 mm/month, P = .002). Those with smaller pulmonary valve were more likely to be cyanotic (P = .05), to undergo surgery at <1 month (P < .01), and to have a TAP repair (P = .01). Among patients undergoing valve-sparing repair, those with smaller PV underwent more reinterventions for residual valvar PS (P < .01). CONCLUSION Midgestation fetal PV size is predictive of postnatal PV and PA size in TOF. Midgestation PV size has implications for timing and type of surgical management as well as for need for reintervention in valve-sparing repair patients and is therefore important to consider in prenatal counseling for TOF fetuses.


Journal of The American Society of Echocardiography | 2017

Right-Dominant Unbalanced Atrioventricular Septal Defect: Echocardiography in Surgical Decision Making

Alisa Arunamata; Sowmya Balasubramanian; Richard D. Mainwaring; Katsuhide Maeda; Elif Seda Selamet Tierney

Background: Management of right‐dominant atrioventricular septal defect (AVSD) remains a challenge given the spectrum of ventricular hypoplasia. The purpose of this study was to assess whether reported echocardiographic indices and additional measurements were associated with operative strategy in right‐dominant AVSD. Methods: A blinded observer retrospectively reviewed preoperative echocardiograms of patients who underwent surgery for right‐dominant AVSD (January 2000 to July 2013). Ventricular dimensions, atrioventricular valve index (AVVI; left valve area/right valve area), and right ventricular (RV)/left ventricular (RV/LV) inflow angle were measured. A second observer measured a subset of studies to assess agreement. Pearson correlation analysis was performed to examine the relationship between ventricular septal defect size (indexed to body surface area) and RV/LV inflow angle in systole. A separate validation cohort was identified using the same methodology (August 2013 to July 2016). Results: Of 46 patients with right‐dominant AVSD (median age, 1 day; range, 0–11 months), overall survival was 76% at 7 years. Twenty‐eight patients (61%) underwent single‐ventricle palliation and had smaller LV dimensions and volumes, AVVIs (P = .005), and RV/LV inflow angles in systole (P = .007) compared with those who underwent biventricular operations. Three patients undergoing biventricular operations underwent transplantation or died and had lower indexed LV end‐diastolic volumes compared with the remaining patients (P = .005). Interobserver agreement for the measured echocardiographic indices was good (intraclass correlation coefficient = 0.70–0.95). Ventricular septal defect size and RV/LV inflow angle in systole had a strong negative correlation (r = −0.7, P < .001). In the validation cohort (n = 12), RV/LV inflow angle in systole ≤ 114° yielded sensitivity of 100% and AVVI ≤ 0.70 yielded sensitivity of 88% for single‐ventricle palliation. Conclusions: Mortality remains high among patients with right‐dominant AVSD. RV/LV inflow angle in systole and AVVI are reproducible measurements that may be used in conjunction with several echocardiographic parameters to support suitability for a biventricular operation in right‐dominant AVSD.


Journal of The American Society of Echocardiography | 2017

Left Ventricular Systolic Myocardial Deformation: A Comparison of Two- and Three-Dimensional Echocardiography in Children

Sowmya Balasubramanian; Rajesh Punn; Shea N. Smith; Helene Houle; Theresa A. Tacy

Background: The clinical applicability and reliability of three‐dimensional (3D) speckle‐tracking echocardiography has not been well studied in pediatric patients. The aim of this study was to compare two‐dimensional (2D) echocardiography and 3DE real‐time full‐volume–derived strain and rotation indices in healthy children and patients with dilated cardiomyopathy (DCM). Methods: Children with either normal function or DCM were prospectively recruited in an outpatient setting, and deformation indices, including circumferential, radial, and longitudinal strain and torsion, were measured by 2D and 3D echocardiography. Control subjects were compared with patients using the Mann‐Whitney U test, correlations between 2D and 3D measurements were analyzed using Spearman correlation analysis, and reproducibility analyses are reported using intraclass correlation coefficients and coefficient of variations. Results: The study cohort consisted of 15 patients (47%) with DCM and 17 control subjects (53%). The median age of the cohort was 13.4 years (range, 5.7–19.3 years). By both 2D and 3D analysis, magnitudes of global longitudinal (P = .01), circumferential (P = .007), and radial (P = .004) strain were significantly lower in patients with DCM in comparison with control subjects. Using receiver operating characteristic curves, lower values of absolute circumferential (area under the curve = 0.95, P < .0001) and longitudinal (area under the curve = 0.93, P < .0001) strain were associated with left ventricular dysfunction. No difference was noted in torsion between control subjects and patients. Three‐dimensional analysis was superior to 2D analysis in terms of intraobserver, interobserver, and test‐retest reliability. Conclusions: Left ventricular deformation shows significant changes while torsion is preserved in outpatients with DCM compared with control subjects. Three‐dimensional global strain can discriminate subtle left ventricular dysfunction and has better reproducibility in comparison with 2D echocardiography. High‐resolution 3D imaging is a useful clinical assessment tool for cardiac performance and may overcome some of the limitations of 2D analysis. HighlightsThree‐dimensional speckle‐tracking echocardiography‐derived mechanics is feasible and a highly reproducible modality that can be used to characterize ventricular function.This prospective study compared 3D and 2D echocardiography‐derived mechanics in healthy children and in pediatric patients with dilated cardiomyopathy.Global strain showed significant changes while torsion was preserved in outpatients with dilated cardiomyopathy compared to controls.Three‐dimensional echocardiography‐derived mechanics is a useful clinical assessment tool for cardiac performance and may overcome some of the limitations of 2D analysis.


Journal of The American Society of Echocardiography | 2017

Echocardiography-Derived Left Ventricular Outflow Tract Gradient and Left Ventricular Posterior Wall Thickening Are Associated with Outcomes for Anatomic Repair in Congenitally Corrected Transposition of the Great Arteries

Shreya Moodley; Sowmya Balasubramanian; Theresa A. Tacy; Frandics P. Chan; Rajesh Punn

Background: Congenitally corrected transposition of the great arteries is a rare form of congenital heart disease. Management is controversial; options include observation, physiologic repair, and anatomic repair. Assessment of morphologic left ventricle preparedness is key in timing anatomic repair. This studys purpose was to review the modalities used to assess the morphologic left ventricle preoperatively and to determine if any echocardiographic variables are associated with outcomes. Methods: A retrospective review of patients with congenitally corrected transposition of the great arteries eligible for anatomic repair at Lucile Packard Childrens Hospital from 2000 to 2016 was conducted. Inclusion criteria were (1) presurgical echocardiography, magnetic resonance imaging, and cardiac catheterization and (2) clinical follow‐up information. Echocardiographic measurements included left ventricular (LV) single‐plane Simpsons ejection fraction, LV eccentricity index, LV posterior wall thickening, pulmonary artery band (PAB)/LV outflow tract (LVOT) pressure gradient, and LV and right ventricular strain. Magnetic resonance imaging measurements included LV mass, ejection fraction, eccentricity index, and LV thickening. LV pressure, PAB/LVOT gradient, right ventricular pressure, pulmonary vascular resistance, and Qp/Qs constituted catheterization data. Outcomes included achieving anatomic repair within 1 year of assessment in patients with LVOT obstruction or within 1 year of pulmonary artery banding and freedom from death, transplantation, or heart failure at last follow‐up. Results: Forty‐one patients met the inclusion criteria. PAB/LVOT gradients of 85.2 ± 23.4 versus 64.0 ± 32.1 mm Hg (P = .0282) by echocardiography and 60.1 ± 19.4 versus 35.9 ± 18.9 mm Hg (P = .0030) by catheterization were associated with achieving anatomic repair and freedom from death, transplantation, and heart failure. Echocardiographic LV posterior wall thickening of 35.4 ± 19.8% versus 20.6 ± 15.0% (P = .0017) and MRI LV septal wall thickening of 37.1 ± 18.8% versus 19.3 ± 18.8% (P = .0306) were associated with achieving anatomic repair. Inter‐ and intraobserver variability for echocardiographic measurements was very good. Conclusions: PAB/LVOT gradient and LV posterior wall thickening are highly reproducible echocardiographic measurements that reflect morphologic LV performance and can be used in assessing patients with congenitally corrected transposition of the great arteries undergoing anatomic repair. HighlightsThe authors assessed imaging techniques in patients with CCTGA.Echocardiography was an important tool for assessing the morphologic left ventricle before anatomic repair.Intrinsic or PAB‐associated LVOT gradient was a useful measurement of LV preparedness for anatomic repair.LVPW thickening was also useful in assessing the left ventricle before anatomic repair.


Annals of Pediatric Cardiology | 2017

Chronic antepartum maternal hyperoxygenation in a case of severe fetal Ebstein's anomaly with circular shunt physiology

Alisa Arunamata; David M. Axelrod; Katherine Bianco; Sowmya Balasubramanian; Amy Quirin; Theresa A. Tacy

Perinatal mortality remains high among fetuses diagnosed with Ebsteins anomaly of the tricuspid valve. The subgroup of patients with pulmonary valve regurgitation is at particularly high risk. In the setting of pulmonary valve regurgitation, early constriction of the ductus arteriosus may be a novel perinatal management strategy to reduce systemic steal resulting from circular shunt physiology. We report the use of chronic antepartum maternal oxygen therapy for constriction of the fetal ductus arteriosus and modulation of fetal pulmonary vascular resistance in a late presentation of Ebsteins anomaly with severe tricuspid valve regurgitation, reversal of flow in the ductus arteriosus, and continuous pulmonary valve regurgitation.

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Theresa A. Tacy

Lucile Packard Children's Hospital

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Alisa Arunamata

Lucile Packard Children's Hospital

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Kathy J. Jenkins

Boston Children's Hospital

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Alan Nugent

University of Texas Southwestern Medical Center

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