The Role of Echocardiography and Intracardiac Exploration in the Evaluation of Candidacy for Biventricular Repair in Patients With Borderline Left Heart Structures

Hypoplastic Left Ventricle: Hypoplastic Left Heart Complex

Hypoplastic left heart syndrome (HLHS) without intrinsic valvar stenosis or atresia is synonymous with the term hypoplastic left heart complex (HLHC) and is defined as a cardiac malformation at the milder end of the spectrum of HLHS with normally aligned great arteries without a common atrioventricular junction, characterized by underdevelopment of the left heart with significant hypoplasia of the left ventricle and hypoplasia of the aortic or mitral valve, or both valves, in the absence of intrinsic valvar stenosis or atresia, and with hypoplasia of the ascending aorta and aortic arch. This article describes the definitions, nomenclature, and classification of HLHC; the indications and contraindications for biventricular repair of HLHC; the surgical treatment of HLHC; and the associated outcomes.

Hypoplastic Left Ventricle: Left Ventricular Recruitment With Hybrid Approach

Decision-making for biventricular repair (BVR) or univentricular palliation is challenging in neonates with hypoplastic left heart complex (HLHC). Hybrid strategy can be used successfully to achieve BVR in some of these patients. Between June 1998 and January 2022, 342 patients with a diagnosis of HLHS/variants, ductal-dependent lower body circulation with two ventricles, or HLHC with borderline left ventricle (LV) underwent initial bilateral pulmonary artery banding and ductal stenting in our institution. Among these 342 patients, 224 patients were defined as HLHS/variants and underwent univentricular palliation. 118 patients were determined to have borderline LV and hypoplastic left ventricular structures (HLHC, n = 48) or ductal-dependent lower body circulation with two ventricles (n = 70) considered suitable for BVR. 48 patients had multilevel obstructions including both aortic and mitral valve hypoplasia, aortic arch hypoplasia, and borderline LV. These were considered to have HLHC. These 48 HLHC patients are the subject of this report. Neonatal hybrid palliation at a median age of seven days was performed in 48 patients and 46 patients underwent BVR at a median age of 156 days. In 46 patients who underwent BVR, hospital mortality was not observed. The median follow-up was 66 months, with no late mortality. Heart transplant-free survival at 5, 10, and 15 years was 95.7%. 12 patients (26%) required reoperation and 9 (19.5%) required catheter reinterventions. Hybrid palliation may increase the chances for biventricular circulation in patients with borderline LV and small left-sided structures. Giessen hybrid approach as a left ventricular recruitment strategy achieves excellent early and long-term results.

Biventricular Conversion for Hypoplastic Left Heart Variants: An Update

Ongoing concerns with single-ventricle palliation morbidity and poor outcomes from primary biventricular strategies for neonates with borderline left heart structures have led some centers to attempt alternative strategies to obviate the need for ultimate Fontan palliation and limit the risk to the child during the vulnerable neonatal period. In certain patients who are traditionally palliated toward single-ventricle circulation, biventricular circulation is possible. This review aims to delineate the current knowledge regarding converting certain patients with borderline left heart structures from single-ventricle palliation toward biventricular circulation.

Left heart hypoplasia in the fetus: echocardiographic predictors of outcome

INTRODUCTION

Fetal left heart hypoplasia (LHH) with an apex-forming left ventricle may require neonatal intervention but it is difficult to predict.

METHODS

We performed a retrospective study of fetuses with LHH defined as normal segmental anatomy, apex-/near-apex forming left ventricle, and ≥1 left-sided Z-score <-2 between 1997-2014. Fetuses with mitral or aortic atresia, critical aortic stenosis, extracardiac anomalies, or fetal intervention were excluded. Classification and regression tree analyses (CART) were performed to construct algorithms to predict postnatal circulation: no surgery versus biventricular surgery versus single ventricle (SV) palliation.

RESULTS

Among 138 included fetuses, 52 (37%) underwent neonatal surgery, with 10 (7%) undergoing SV palliation. The strongest single outcome discriminator was exclusively left-to-right flow foramen ovale (FO) flow >32 weeks gestational age (seen in 0% with no surgery, 22% with biventricular surgery, 88% with SV palliation). On CART analysis >32 weeks GA, fetuses with right-to-left FO flow and aortopulmonary ratio >0.76 had 0% probability of neonatal surgery, while those with left-to-right FO flow and mitral valve Z-score <-3.6 had a 70% probability of SV palliation.

CONCLUSION

SV palliation is an uncommon outcome of fetal LHH. Fetal FO flow and other echocardiographic measures can help determine risk and type of postnatal intervention. This article is protected by copyright. All rights reserved.

Management of Interrupted Aortic Arch With Associated Anomalies: A Single-Center Experience

OBJECTIVES

Interrupted aortic arch (IAA) includes a broad spectrum of associated anomalies. In this study, we present our surgical management and patient-specific decisions regarding IAA anomalies with early- and mid-term outcomes.

METHODS

The medical records of 25 patients undergoing IAA repair between 2014 and 2019 were retrospectively reviewed. Sixteen patients had type B (64%) interruptions, 7 had type A (28%) interruptions, and 2 had type C (8%) interruptions. Fourteen patients had an isolated ventricular septal defect, and 3 of them had associated left ventricular outflow tract obstruction. Other associated anomalies were functional single ventricle (n = 5), Taussig-Bing anomaly (n = 3), aortopulmonary window (n = 1), multiple ventricular septal defects (n = 1), and truncus arteriosus with dextrocardia (n = 1). The initial operation age was 17.2 ± 14 (range: 1 - 60) days.

RESULTS

Single-stage total repair was performed for 15 patients. Six patients underwent aortic arch repair and pulmonary artery banding. Four patients with left ventricular outflow tract obstruction or who were premature underwent the hybrid procedure. The aortic arch repair was performed in 16 cases (64%) by the anterior patch augmentation technique, in 3 cases (12%) by the reverse left subclavian artery flap technique, and in 3 cases (12%) by direct end-to-end anastomosis. Postoperative early mortality occurred in 4 (16%) patients, and sternal closure was delayed in 13 (52%) patients. Three patients who underwent a hybrid procedure due to left ventricular outflow tract obstruction underwent biventricular repair 8 to 13 months later. Eight patients (38%) required reintervention due to arch restenosis during the follow-up period. The mean follow-up was 37.1 ± 21.7 months.

CONCLUSION

Planning surgical treatment according to the characteristics of the patients and accompanying anomalies may improve the results.

Small and borderline left ventricular outflow tract - a perplexing maladie

The left ventricular outflow tract (LVOT) comprises of the subvalvular area, the aortic valve, and the supravalvular region. Obstructive lesion of LVOT is a spectrum with varying levels and degree of obstruction with or without associated hypoplasia of the left ventricle. Decision-making in small and borderline LVOT can be challenging. Imaging modalities such as echocardiography and magnetic resonance imaging and scores based on imaging aid in the decision making in truly borderline cases. Newer treatment strategies like staged left ventricular rehabilitation and hybrid procedure have come to the fore in the past decade or so. Although these do not address small LVOT per se, they delay the decision-making to a more appropriate age. The goal of management in these cases is to achieve a biventricular repair whenever feasible. Several surgical techniques could be employed to achieve this goal. However, it is important to be cognizant of the fact that an overzealous approach to achieve a biventricular repair might be counterproductive. A univentricular palliation could be a safer alternative; especially considering the possibility of a future transplant candidacy.

Role of echocardiographic scoring systems in predicting successful biventricular versus univentricular palliation in neonates with critical aortic stenosis

BACKGROUND

There are several published echo-derived scores to help predict successful biventricular versus univentricular palliation in neonates with critical aortic stenosis. This study aims to determine whether any published scoring system accurately predicted outcomes in these neonates.

METHODS

Single centre, retrospective cohort study including neonates who underwent aortic valve intervention (surgical valvotomy or balloon valvuloplasty) with the intention of biventricular circulation. Primary outcome was survival with biventricular circulation at hospital discharge. Data from their initial neonatal echocardiogram were used to compute the following scores - Rhodes, CHSS 1, Discriminant, CHSS 2, and 2 V.

RESULTS

Between 01/1999 and 12/2017, 68 neonates underwent aortic valve intervention at a median age of 4 days (range 1-29 days); 35 surgical valvotomy and 33 balloon valvuloplasty. Survival with biventricular circulation was maintained in 60/68 patients at hospital discharge. Of the remaining eight patients, three were converted to univentricular palliation, four died, and one underwent heart transplant prior to discharge. None of the binary score predictions of biventricular versus univentricular (using that score's proposed cut-offs) were significantly associated with the observed outcome in this cohort. A high percentage of those predicted to need univentricular palliation had successful biventricular repair: 89.4% by Rhodes, 79.3% by CHSS 1, 85.2% by Discriminant, and 66.7% by CHSS 2 score. The 2 V best predicted outcome and agreed with the local approach in most cases.

CONCLUSION

This study highlights the limitations of and need for alternative scoring systems/cut-offs for consistently accurate echocardiographic prediction of early outcome in neonates with critical aortic stenosis.