Midterm Follow-Up After Biventricular Repair of the Hypoplastic Left Heart Complex

Contemporary management of borderline left ventricle

Borderline left ventricle cases present considerable difficulties in determining the most effective surgical approaches. The evolution of approaches in the field has shifted from classical systemic pulmonary shunts to orthodox univentricular palliation and has subsequently seen the emergence of biventricular repair concepts. The concept of biventricular repair for borderline left heart conditions has developed through studies that aim to establish predictive scoring systems for identifying appropriate candidates. Despite continuous efforts, a definitive scoring system for guiding this decision is still difficult to find. There is a growing trend to provide neonatal patients with borderline ventricles with options other than univentricular palliation. Several centres have developed personalized strategies, including hybrid and staged ventricular recruitment approaches. These strategies provide sufficient time for personalized decision-making, taking into account the individual circumstances of each patient. This article presents an overview of the changing approaches to borderline left ventricular cases. It discusses the use of predictive scoring systems and emphasizes the advancements in staged strategies that improve the likelihood of successful biventricular repairs.

Neonates and Infants with Left Heart Obstruction and Borderline Left Ventricle Undergoing Biventricular Repair: What Do We Know about Long-Term Outcomes? A Critical Review

BACKGROUND

The decision to perform biventricular repair (BVR) in neonates and infants presenting with either single or multiple left ventricle outflow obstructions (LVOTOs) and a borderline left ventricle (BLV) is subject to extensive discussion, and limited information is known regarding the long-term outcomes. As a result, the objective of this study is to critically assess and summarize the available data regarding the prognosis of neonates and infants with LVOTO and BLV who underwent BVR.

METHODS

In February 2023, we conducted a review study with three different medical search engines (the National Library of Medicine, Science Direct, and Cochrane Library) for Medical Subject Headings and free text terms including "congenital heart disease", "outcome", and "borderline left ventricle". The search was refined by adding keywords for "Shone's complex", "complex LVOT obstruction", "hypoplastic left heart syndrome/complex", and "critical aortic stenosis".

RESULTS

Out of a total of 51 studies, 15 studies were included in the final analysis. The authors utilized heterogeneous definitions to characterize BLV, resulting in considerable variation in inclusion criteria among studies. Three distinct categories of studies were identified, encompassing those specifically designed to evaluate BLV, those focused on Shone's complex, and finally those on aortic stenosis. Despite the challenges associated with comparing data originating from slightly different cardiac defects and from different eras, our results indicate a favorable survival rate and clinical outcome following BVR. However, the incidence of reintervention remains high, and concerns persist regarding residual pulmonary hypertension, which has been inadequately investigated.

CONCLUSIONS

The available data concerning neonates and infants with LVOTO and BLV who undergo BVR are inadequate and fragmented. Consequently, large-scale studies are necessary to fully ascertain the long-term outcome of these complex defects.

Echocardiographic scores for biventricular repair risk prediction of congenital heart disease with borderline left ventricle: a review

The aim of this review is to highlight the strengths and limitations of major echocardiographic biventricular repair (BVR) prediction models for borderline left ventricle (LV) in complex congenital heart disease (CHD). A systematic search in the National Library of Medicine for Medical Subject Headings and free text terms including echocardiography, CHD, and scores, was performed. The search was refined by adding keywords for critical aortic stenosis (AS), borderline LV, complex left ventricular outflow tract (LVOT) obstruction, hypoplastic left heart syndrome/complex (HLHS/HLHC), and unbalanced atrio-ventricular septal defects (uAVSD). Fifteen studies were selected for the final analysis. We outlined what echocardiographic scores for different types of complex CHD with diminutive LV are available. Scores for CHD with LVOT obstruction including critical AS, HLHS/HLHC, and aortic arch hypoplasia have been validated and implemented by several studies. Scores for uAVSD with right ventricle (RV) dominance have also been established and implemented, the first being the atrioventricular valve index (AVVI). In addition to AVII, both LV/RV inflow angle and LV inflow index have all been validated for the prediction of BVR. We conclude with a discussion of limitations in the development and validation of each of these scores, including retrospective design during score development, heterogeneity in echocardiographic parameters evaluated, variability in the definition of outcomes, differences in adopted surgical and Interventional strategies, and institutional differences. Furthermore, scores developed in the past two decades may have little clinical relevance now. In summary, we provide a review of echocardiographic scores for BVR in complex CHD with a diminutive LV that may serve as a guide for use in modern clinical practice.

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.

Biventricular Conversion of Borderline Hypoplastic Left Heart Complex Facilitated by Spontaneous Closure of the Atrial Septum

We present the case of a child with borderline hypoplastic left heart complex who initially received Norwood and Glenn operations without atrial septectomy and was later converted to a biventricular circulation after progressive growth of the left ventricle as assessed by serial echocardiography and cardiac magnetic resonance imaging.

Case report: duct dependency in hypoplastic left heart complex can be reversible without surgery

We describe an infant with duct-dependent hypoplastic left heart complex with moderate hypoplasia of the left ventricle and aortic arch who was not operated due to resource limitations. The left-sided structures grew remarkably due to favourable loading condition changes of the left ventricle, allowing weaning from prostaglandin at the age of 3 months and discharging the patient without intervention.

Biventricular Conversion in the Borderline Hypoplastic Heart

PURPOSE OF REVIEW

The development of biventricular repair and conversion pathways for patients with borderline hypoplastic heart disease represents an area of recent inquiry and innovation. This review summarizes emerging techniques and novel treatment algorithms for borderline hypoplastic heart disease with a focus on surgical advances within the last 10 years.

RECENT FINDINGS

Many patients with borderline hypoplastic heart disease are amenable to primary biventricular repair, or biventricular conversion following single-ventricle palliation coupled with ventricular rehabilitation strategies. New insights into the potential for growth and recovery of borderline ventricles have been uncovered. However, questions remain regarding optimal patient selection and the long-term outcomes of select patient groups treated with single-ventricle palliation versus biventricular repair/conversion or transplantation. Efforts to direct a greater proportion of borderline hypoplastic heart patients towards a biventricular circulation are accelerating and represent important avenues for progress and future research in the field of congenital heart disease.

Follow-up after biventricular repair of the hypoplastic left heart complex

OBJECTIVES

In hypoplastic left heart complex patients, biventricular repair is preferred over staged-single ventricle palliation; however, there are too few studies to support either strategy. Therefore, we retrospectively characterized our patient cohort with hypoplastic left heart complex after biventricular repair to measure left-sided heart structures and assess our treatment strategy.

METHODS

Patients with hypoplastic left heart complex who had biventricular repair between 2004 and 2018 were retrospectively reviewed. Operative results were evaluated and echocardiographic mitral valve (MV) and aortic valve (AoV) dimensions, left ventricular length and left ventricular internal diastolic diameter (LVIDd) were measured preoperatively and during follow-up after 0.5, 1, 3, 5 and 10 years.

RESULTS

In 32 patients, the median age at surgery was 10 (interquartile range 5.0) days. The median follow-up was 6.19 (interquartile range 6.04) years. During the 10-year follow-up, the mean Z-scores increased from -2.82 to -1.49 and from -2.29 to 0.62 for MV and AoV, respectively. Analysis of variance results with post hoc paired t-tests showed that growth of left-sided heart structures was accelerated in the first year after repair, but was not equal, with the MV lagging behind the AoV (P = 0.033), resulting in significantly smaller MV Z-scores compared with AoV Z-scores at 10-year follow-up (P < 0.001). There were 2 (6%) early deaths. The major adverse events occurred in 4 (13%) patients. The surgical or catheter-based reintervention was required in 14 (44%) patients.

CONCLUSIONS

The growth rate of heart structures was most prominent during the first year after biventricular repair with lower growth rate of the MV compared with the AoV.

Surgical Outcomes of Biventricular Repair for Hypoplastic Left Ventricle With Congenital Mitral Valve Stenosis

Objective:

Surgical outcomes of biventricular repair for hearts with hypoplastic left ventricle with congenital mitral valve stenosis are described. Serial changes of left ventricular geometry and clinical features after biventricular repair were reviewed.

Methods:

Eight patients with hypoplastic left ventricle and congenital mitral valve stenosis who underwent first surgical intervention for biventricular circulation in neonatal or infantile period between 2001 and 2014 comprise the study population. Serial change in left ventricular end-diastolic diameter, left ventricular mass index, and relative wall thickness after biventricular repair were evaluated by two-dimensional echocardiography.

Results:

The median Z-scores of left ventricular end-diastolic diameter and mitral valve diameter before the first surgical intervention were −3.0 (range, −4.8 to −2.0) and −1.0 (−2.9 to 2.1), respectively. Mitral valves were surgically treated in five patients; they were replaced in two and repaired in three patients. Left ventricular end-diastolic diameter Z-score at five years after biventricular repair was 0.1 (−3.0 to 1.0), which was significantly larger than before first surgical intervention ( P = .005). Left ventricular mass index, on the other hand, did not change, but relative wall thickness significantly decreased ( P = .009). Postoperative catheter study showed pulmonary hypertension with high left ventricular end-diastolic pressure in more than half of survivors.

Conclusions:

Left ventricle increased in size after the biventricular repair with appropriate mitral valve procedures before progression of pulmonary hypertension. Left ventricular mass, however, did not accompany the increase. Some patients may have suffered from mild, but certain restrictive left ventricular physiology and subsequent pulmonary hypertension as the result of abnormal remodeling process of the myocardium.