Shobha Natarajan

Perinatal and early surgical outcome for the fetus with hypoplastic left heart syndrome: a 5-year single institutional experience.

To review our experience with the prenatal diagnosis of hypoplastic left heart syndrome (HLHS). Our goal was to establish the benchmark for perinatal and early surgical outcome in the current era, from a center with an aggressive surgical approach and a cohort with a high level of intention‐to‐treat.

Speckle Tracking-Derived Myocardial Tissue Deformation Imaging in Twin-Twin Transfusion Syndrome: Differences in Strain and Strain Rate between Donor and Recipient Twins

Objectives: Twin-twin transfusion syndrome (TTTS) is a complex disorder with altered cardiovascular loading conditions that affects both donors and recipients. Myocardial tissue deformation analysis using vector velocity imaging is an angle-independent, speckle-tracking technique which can assess myocardial mechanics and may provide insight into cardiac dysfunction in TTTS. Methods: Digital dynamic two-dimensional four-chamber views were interrogated offline. Images were acquired utilizing standard video frame rates (30 frames/s). The global longitudinal strain, systolic strain rate, and diastolic strain rate were measured in the left (LV) and right ventricles (RV) of 25 fetal pairs with TTTS and compared to 25 gestational age-matched normal controls. Pulsatility indices for the umbilical artery and middle cerebral artery were measured. Results: The gestational age at evaluation was 20.5 ± 1.3 weeks. The donor LV systolic strain rate was higher, while the donor RV diastolic strain rate was significantly lower, than control values. The recipient longitudinal strain, systolic strain rate, and diastolic strain rate were significantly lower for both LV and RV in comparison to controls. The donor umbilical artery pulsatility index was higher than control values (1.92 ± 0.45 vs. 1.41 ± 0.25, p < 0.001), while the donor middle cerebral artery pulsatility index was lower (1.46 ± 0.28 vs. 1.87 ± 0.21). Recipient umbilical artery and middle cerebral artery pulsatility indices were no different than control values. Conclusions: In TTTS, both the donor and the recipient exhibit abnormalities of myocardial tissue deformation with ventricle-specific changes evident based on loading conditions. Donor LV systolic function is hyperdynamic due to hypovolemia and selective ejection into a low-resistance cerebrovascular circuit while the donor RV selectively ejects into a high-resistance placental circuit. Recipient RV and LV are both globally depressed with systolic and diastolic dysfunction. Further prospective validation of our findings using high frame rate analysis is indicated.

Surgical Interventions for Atrioventricular Septal Defect Subtypes: The Pediatric Heart Network Experience

BACKGROUND The influence of atrioventricular septal defect (AVSD) subtype on outcomes after repair is poorly understood. METHODS Demographic, procedural, and outcome data were obtained 1 and 6 months after AVSD repair in an observational study conducted at 7 North American centers. RESULTS The 215 AVSD patients were subtyped as 60 partial, 27 transitional, 120 complete, and 8 with canal-type VSD. Preoperatively, transitional patients had the highest prevalence of moderate or severe left atrioventricular valve regurgitation (LAVVR, p = 0.01). At repair, complete AVSD and canal-type VSD patients, both with the highest prevalence of trisomy 21 (p < 0.001), were younger (p < 0.001), had lower weight-for-age z scores (p = 0.005), and had more associated cardiac defects (p < 0.001). Annuloplasty was similar among subtypes (p = 0.91), with longer duration of ventilation and hospitalization for complete AVSD (p < 0.001). Independent predictors of moderate or severe LAVVR at the 6-month follow-up were older log(age) at repair (p = 0.02) but not annuloplasty, subtype, or center (p > 0.4). Weight-for-age z scores improved in all subtypes at the 6-month follow-up, and improvement was similar among subtypes (p = 0.17). CONCLUSIONS AVSD subtype was significantly associated with patient characteristics and clinical status before repair and influenced age at repair. Significant postoperative LAVVR is the most common sequela, with a similar prevalence across centers 6 months after the intervention. Annuloplasty failed to decrease the postoperative prevalence of moderate or severe LAVVR at 6 months. After accounting for age at repair, AVSD subtype was not associated with postoperative LAVVR severity or growth failure at 6 months. Further investigation is needed to determine if interventional strategies specific to AVSD subtype improve surgical outcomes.

Maternal hyperoxygenation improves left heart filling in fetuses with atrial septal aneurysm causing impediment to left ventricular inflow

Aneurysm of the atrial septum (AAS) with excessive excursion of septum primum into the left atrium is an uncommon and relatively benign fetal condition associated with impediment to left ventricular (LV) filling and the appearance of a slender, but apex‐forming, LV on fetal echocardiography. Impediment to filling can be severe, creating the image of LV hypoplasia with retrograde aortic flow. We hypothesize that maternal hyperoxygenation alters atrial septal position, improves LV filling, and normalizes aortic flow in fetuses with AAS by increasing fetal pulmonary venous return.

The Role of Echocardiography in the Intraoperative Management of the Fetus Undergoing Myelomeningocele Repair

Introduction: Fetal surgery for myelomeningocele (MMC) results in better outcomes compared to postnatal treatment. However, risks are present. We describe our experience with intraoperative fetal echocardiography during repair of MMC and report on the management of serious cardiovascular events. Material and Methods: The subjects included fetuses with intent to repair MMC from January 2011 to February 2014. The protocol involved continuous echocardiography in a looping, sequential manner of systolic function, heart rate and tricuspid and mitral valve regurgitation. Results: A total of 101 cases intended fetal MMC repair; 100 completed surgery. Intraoperative ventricular dysfunction was present in 60% (20 mild, 25 moderate, 15 severe). Heart rate <100 bpm was noted in 11 cases. Tricuspid valve regurgitation was present in 35% (26 mild, 7 moderate, 2 severe); mitral valve regurgitation was present in 19% (15 mild, 4 moderate). Serious cardiovascular events were experienced in 7 cases, which affected the conduct of surgery and/or outcome. In 4 of these, medications were given via the umbilical vein and external cardiac compressions were performed. Fetal echocardiography was used to gauge the efficacy of compressions and to guide resuscitation. Discussion: Cardiovascular compromise is common during fetal surgery for MMC. Intraoperative fetal echocardiography is recommended as a growing number of centers contemplate offering this form of novel, but potentially risky, therapy.

Peripheral Arterial Function in Infants and Young Children With One-Ventricle Physiology and Hypoxemia

Patients with 1-ventricle (1V) physiology may be at risk for peripheral arterial dysfunction at a young age. To determine whether infants and young children with 1V physiology and hypoxemia have peripheral arterial dysfunction before undergoing the Fontan operation, we measured (1) flow-mediated vasodilation (FMD) in the brachial artery, (2) serum levels of vasoactive mediators endothelin-1 (ET-1) and metabolites of nitric oxide, and (3) arterial stiffness with pulse-wave velocity (PWV) in the aorta. Eighteen patients with 1V physiology before the Fontan procedure and hypoxemia and 19 patients with normoxemia and 2-ventricle (2V) physiology were studied. Measurements were collected during cardiac catheterization. FMD in the brachial artery was the diameter gain after 4.5 minutes of forearm occlusion measured with high-resolution ultrasound and edge-detection software. Nitric oxide and ET-1 levels were measured in venous blood. PWV between the left carotid and femoral arteries was measured using pulse Doppler ultrasound. FMD was lower (2.4 +/- 3.7% vs 11.3 +/- 6%, p <0.0005) and ET-1 levels were higher (35.5 +/- 11.3% vs 24.1 +/- 9.7%, p = 0.003) in subjects with 1V physiology versus those with 2V physiology, respectively. There were no differences in nitric oxide levels or PWV. In conclusion, infants and young children with 1V physiology and hypoxemia have blunted FMD and higher ET-1 levels before undergoing the Fontan operation compared with normoxemic subjects with 2V physiology. A further understanding of pathophysiologic mechanisms underlying peripheral arterial dysfunction, including the roles of hypoxemia, low cardiac index, and ET-1, may lead to targeted therapies and improve the long-term survival of patients with 1V physiology.

Superior cavopulmonary anastomosis timing and outcomes in infants with single ventricle

OBJECTIVES We sought to identify factors associated with the timing and surgical outcomes of the superior cavopulmonary anastomosis. METHODS The Pediatric Heart Networks Infant Single Ventricle trial database identified participants who underwent superior cavopulmonary anastomosis. Factors potentially associated with age at superior cavopulmonary anastomosis, length of stay and death by 14 months of age were evaluated. Factors included subject demographics, cardiac anatomy, measures from neonatal hospitalization and pre-superior cavopulmonary anastomosis visit, adverse events, echocardiographic variables, intraoperative variables, superior cavopulmonary anastomosis type, and number of concurrent cardiac surgical procedures. Age at superior cavopulmonary anastomosis was analyzed using Cox proportional hazards regression. Natural log length of stay was analyzed by multiple linear regression. RESULTS Superior cavopulmonary anastomosis was performed in 193 subjects at 5.2 months of age (interquartile range, 4.2, 6.2) and weight of 5.9 kg (interquartile range, 5.3, 6.6). The median length of stay was 7 days (interquartile range, 6, 10). There were 3 deaths and 1 transplant during the superior cavopulmonary anastomosis hospitalization, and 3 deaths and 3 transplants between discharge and 14 months of age. Age at superior cavopulmonary anastomosis was associated with center and interstage adverse events. A longer length of stay was associated with younger age and greater case complexity. Superior cavopulmonary anastomosis type, valve regurgitation, ventricular ejection fraction, and ventricular end-diastolic pressure were not independently associated with age at superior cavopulmonary anastomosis or the length of stay. CONCLUSIONS Greater case complexity and more frequent interstage adverse events are associated with an earlier age at superior cavopulmonary anastomosis. Significant variation in age at superior cavopulmonary anastomosis among centers, independent of subject factors, highlights a lack of consensus regarding the optimal timing. Factors associated with length of stay could offer insights for improving presuperior cavopulmonary anastomosis care and surgical outcome.

Intramural Ventricular Septal Defect is a Distinct Clinical Entity Associated with Postoperative Morbidity in Children after Repair of Conotruncal Anomalies

Background— Intramural ventricular septal defects (VSDs) are interventricular communications through right ventricular free wall trabeculations that can occur after repair of conotruncal anomalies. We assessed the prevalence of residual intramural VSDs and their effect on postoperative course. Methods and Results— Children who underwent biventricular repair of a conotruncal anomaly from January 1, 2006, to June 30, 2013, and had a postoperative transthoracic echocardiogram were included. Images were reviewed for residual intramural or nonintramural VSDs. The primary outcome was a composite of mortality, extracorporeal membrane oxygenation use, and need for subsequent catheter or surgical VSD closure. The secondary outcome was postoperative hospital length of stay. A residual VSD was present in 256 of the 442 subjects (58%), of which 231 (90%) were <2 mm in size. Forty‐nine patients (11%) had intramural VSDs, and 207 (47%) had nonintramural VSDs. Patients with intramural VSDs were more likely to reach the primary composite outcome compared with those with nonintramural VSDs or no residual VSD (14 of 49 [29%] versus 15 of 207 [7%] versus 6 of 186 [3%]; P<0.0001). In addition, those with intramural VSDs had longer postoperative hospital length of stay compared with those with nonintramural VSDs or no residual VSD (20 days [interquartile range, 11‐42 days] versus 7 days [interquartile range, 5‐14 days] versus 6 days [interquartile range, 4‐11 days]; P=0.0001). These associations remained significant after adjustment for known risk factors for poor outcomes, including residual VSD size and operative complexity. Conclusions— Among residual VSDs after repair of conotruncal anomalies, intramural VSDs are uniquely associated with postoperative morbidity, mortality, and longer postoperative hospital length of stay. It is important to recognize intramural VSDs in the postoperative period.

Chest pain with elevated troponin assay in adolescents.

OBJECTIVE We sought to describe the evaluation, treatment, and follow-up of adolescents who presented to a single institution with chest pain and an elevated troponin I value in the absence of typical symptoms of pericarditis or myocarditis. Materials and methods We performed a retrospective review of patients in the age group of 10-18 years of age with no history of significant heart disease admitted to our institution from 2000 to 2010 after presenting with chest pain and an elevated troponin I value. RESULTS A total of 16 patients were identified with a median age of 16.5 years (range 11.2-17.8 years). Of these 13 (81%) were male and 10 (63%) showed evidence of localised ST elevations on electrocardiogram. The median peak troponin I level was 17.8 nanograms per millilitre (range 0.89-227, normal less than 0.4). There were eight patients (50%) with a diagnosis of coronary vasospasm, three patients (20%) with atypical myopericarditis, one patient with coronary anomaly, one patient with hypercoagulable disorder, and one patient with prolonged supraventricular tachycardia. In two patients, no definitive diagnosis was made. There was one patient who needed catheter-based intervention, which involved stenting of a coronary artery after a procedure-related complication. CONCLUSIONS In our cohort of adolescents without history of significant cardiac disease, chest pain and elevated troponin I levels were attributed to a variety of causes. Although coronary vasospasm and atypical myopericarditis were seen most commonly, coronary anomaly was identified in one case. Magnetic resonance imaging proved a useful diagnostic tool to assess coronary artery anatomy and myocardial changes suggestive of myocarditis. On the basis of these results and a review of the literature, a general evaluation algorithm is presented.

Reproducibility of Left Ventricular Dimension Versus Area Versus Volume Measurements in Pediatric Patients With Dilated CardiomyopathyCLINICAL PERSPECTIVE

Background— Multiple echocardiographic methods are used to measure left ventricular size and function. Clinical management is based on individual evaluations and longitudinal trends. The Pediatric Heart Network VVV study (Ventricular Volume Variability) in pediatric patients with dilated cardiomyopathy has reported reproducibility of several of these measures, and how disease state and number of beats impact their reproducibility. In this study, we investigated the impact of observer and sonographer variation on reproducibility of dimension, area, and volume methods to determine the best method for both individual and sequential evaluations. Methods and Results— In 8 centers, echocardiograms were obtained on 169 patients prospectively. During the same visit, 2 different sonographers acquired the same imaging protocol on each patient. Each acquisition was analyzed by 2 different observers; first observer analyzed the first acquisition twice. Intraobserver, interobserver, interacquisition, and interobserver-acquisition (different observers and different acquisition) reproducibility were assessed on measurements of left ventricular end-diastolic dimension, area, and volume. Left ventricular shortening fraction, ejection fraction, mass, and fractional area change were calculated. Percent difference was calculated as (interobservation difference/mean)×100. Interobserver reproducibility for both acquisitions was better for both volume and dimension measurements (P⩽0.002) compared with area measurements, whereas intraobserver, interacquisition (for both observers), and interobserver-acquisition reproducibilities (for both observer-acquisition sets) were best for volume measurements (P⩽0.01). Overall, interobserver-acquisition percent differences were significantly higher than interobserver and interacquisition percent differences (P<0.001). Conclusions— In pediatric patients with dilated cardiomyopathy, compared with dimension and area methods, left ventricular measurements by volume method have the best reproducibility in settings where assessment is not performed by the same personnel. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT00123071.