Factors associated with morbidity, mortality, and hemodynamic failure after biventricular conversion in borderline hypoplastic left hearts

Practical approach to using cardiac magnetic resonance imaging for pre-surgical planning in complex paediatric congenital heart disease

Decision-making in complex congenital heart disease (CHD) is challenging and requires the integration of anatomic and physiological data. Recent advances in cross-sectional imaging, particularly cardiac magnetic resonance imaging (MRI), have refined this process. In addition to anatomic detail, MRI provides quantitative physiological data on cardiac function and flows through volumetry and phase contrast assessment. This review outlines the current scope for cardiac MRI and aims to provide a practical framework for using the data in four structural anomalies: borderline left ventricle, double outlet right ventricle, congenitally corrected transposition of the great arteries and Ebstein anomaly of the tricuspid valve.

Biventricular Repair of Univentricular Heart Lowers Risk of Liver Disease Compared With the Fontan Operation

Background

The Fontan operation is associated with chronic venous hypertension, liver and renal disease, and several other sequelae. The alterative surgical approach, when feasible, a biventricular conversion (BiV), may diminish some of these long-term risks.

Objectives

The aim of this study was to compare long-term outcomes of patients undergoing BiV with those undergoing a destination Fontan operation.

Methods

We identified all patients with univentricular physiology cared for at Boston Children's Hospital between 2007 and 2022 and divided them into those who received BiV or Fontan operations. Outcomes included 10-year incidences of modified major adverse cardiovascular events (MACE), liver dysfunction, renal dysfunction, and transplant-free survival. Outcomes in the 2 groups were compared using propensity matching.

Results

A total of 927 patients were evaluated, 341 BiV and 586 Fontan. Following propensity matching, 258 patients from each group were compared. There were no differences between groups in estimated 10-year freedom from MACE (P = 0.70), transplant-free survival (P = 0.70), or freedom from renal disease (P = 0.60). However, estimated 10-year freedom from liver disease was greater in BiV patients (82% BiV vs 71% Fontan, P = 0.02). Incidence rate per 100 person-years follow-up of surgical interventions and readmissions was higher among BiV patients (10.11 vs 1.85, P < 0.001 and 13.09 vs 9.6, P = 0.002), while catheter-based interventions were higher among Fontan patients (8.41 vs 4.63, P < 0.001).

Conclusions

Among a contemporary cohort of patients with single ventricle anatomy, BiV provide comparable long-term survival and lower risk of liver disease when compared to patients who have undergoing Fontan operations.

Wide variation in shape of hypoplastic left ventricles undergoing recruitment and biventricular repair: A statistical shape modeling study

BACKGROUND

Patients with hypoplastic left ventricles (LV) who undergo volume-loading procedures (recruitment, biventricular [BIV] repair) are at risk for adverse outcomes, including heart failure and death. We investigated pre-BIV LV shape as a predictor of outcome after BIV repair in patients with hypoplastic LVs.

METHODS

Baseline and post-recruitment cardiac magnetic resonance imaging and computed tomography data were analyzed in patients with hypoplastic LV (<50 mL/m2). Statistical shape modeling (SSM) was utilized to generate a model of the shape and variability of LVs. Traditional measures of LV sphericity and eccentricity were also measured. Major adverse cardiovascular events (MACE) included heart failure, transplant, and death.

RESULTS

Of 95 patients with baseline mean LV volume 29 ± 13 mL/m2, 45/95 (47%) had a right dominant atrioventricular canal defect, 31/95 (33%) had a variant of hypoplastic left heart syndrome, and 18/95 (19%) had endocardial fibroelastosis (EFE). A wide variation in LV shape was found by SSM, and shape modes were associated with right ventricle (RV) and LV size, and diagnosis. BIV repair was achieved in 74/95 (78%) patients; 13/74 (18%) of BIV patients had MACE. Predictors of MACE following BIV repair included EFE, higher RV mass index, and higher RV end-diastolic volume index. No baseline or post-recruitment LV shape parameter was associated with the outcome after BIV repair.

CONCLUSION

The shape model of hypoplastic LVs demonstrated a wide array of LV shapes. LVs gained sphericity and size and lost eccentricity with recruitment. Though the ventricles changed shape with recruitment, no specific LV shape characteristic at the baseline or post-recruitment stage was predictive of decision to proceed with BIV repair or outcome. Higher RV mass and volume may represent new biomarkers that predict outcomes following BIV repair in patients with hypoplastic LV. Further investigation could determine the reproducibility of these findings.

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.

Borderline Ventricles: From Evaluation to Treatment

A heart with a borderline ventricle refers to a situation where there is uncertainty about whether the left or right underdeveloped ventricle can effectively support the systemic or pulmonary circulation with appropriate filling pressures and sufficient physiological reserve. Pediatric cardiologists often deal with congenital heart diseases (CHDs) associated with various degrees of hypoplasia of the left or right ventricles. To date, no specific guidelines exist, and surgical management may be extremely variable in different centers and sometimes even in the same center at different times. Thus, the choice between the single-ventricle or biventricular approach is always controversial. The aim of this review is to better define when "small is too small and large is large enough" in order to help clinicians make the decision that could potentially affect the patient's entire life.

Staged repair of borderline hypoplastic heart disease with early biventricular conversion

Objective

In select patients with borderline ventricular hypoplasia, we adopted a strategy of initial single-ventricle palliation followed by staged or direct biventricular conversion by 2 years of age.

Methods

Between 2018 and 2023, 14 newborns with borderline hypoplastic heart disease deemed high risk for primary biventricular repair underwent palliative procedures as a neonate/infant, followed by staged or direct biventricular conversion.

Results

Of the 14 patients, 6 had borderline left ventricles and 8 had borderline right ventricles. Index neonatal operations were performed in 12 patients and included the Norwood operation (n = 5), pulmonary artery band (n = 3), ductal stent (n = 3), and hybrid Norwood (n = 1). Five patients underwent direct biventricular conversion, and the remaining 9 patients underwent staged ventricular recruitment operations at a mean age of 6 months (range, 3-11 months). Ventricular recruitment operations included atrial septation with or without ventricular rehabilitation, atrioventricular valve repair, or outflow tract operations. At a mean duration of 8 months (range, 4-10 months) after ventricular recruitment, there was a significant increase in chamber volume, aortic valve, and mitral valve size in patients with borderline left ventricles, and a normalization of the right ventricle:left ventricle end-diastolic volume ratio in patients with borderline right ventricles. To date, 13 of 14 patients have undergone successful biventricular conversion at a mean age of 16 months (range, 4-31 months).

Conclusions

In select newborns with borderline hypoplastic heart disease, single-ventricle palliation followed by staged or direct biventricular conversion may increase infant survival while allowing for early attainment of a biventricular circulation.

Endocardial Fibroelastosis Resection: When it Works and When it Does Not

Endocardial fibroelastosis (EFE) is a thickening of the endocardial layer by accumulation of collagen and elastic fibers. Endothelial to mesenchymal transformation is proposed to be the underlying mechanism of formation. Although EFE can occur in both right and left ventricles, this article will focus on management of left ventricular EFE. Through its fibrous, nonelastic manifestation EFE restricts the myocardium leading to diastolic and systolic ventricular dysfunction and prevents ventricular growth in neonates and infants. The presence of EFE may be a marker for underlying myocardial fibrosis as well. The extent of EFE within the left ventricular cavity can be variable ranging from patchy to confluent distribution. Similarly the depth of penetration and degree of infiltration into myocardium can be variable. The management of EFE is controversial, although resection of EFE has been reported as part of the staged ventricular recruitment therapy. Following resection, EFE recurs and infiltrates the myocardium after primary resection. Herein we review the current experience with EFE resection.