Early Experience With Reverse Double Switch Operation for the Borderline Left Heart

Reverse double switch operation for the borderline left ventricle

OBJECTIVE(S)

This study investigates outcomes of the reverse double switch operation (R-DSO) and ventricular switch, novel approaches for patients with D-looped borderline left hearts that utilize the morphologic right ventricle as the systemic ventricle and the hypoplastic left ventricle as the subpulmonary ventricle.

METHODS

This retrospective review analyzed early outcomes of children who underwent R-DSO/ventricular switch at a single institution between 2015 and 2023. Our primary end points were right ventricular (RV) function and tricuspid regurgitation. Secondary outcomes included mortality, reoperation, and perioperative complications.

RESULTS

Twenty-eight patients underwent either R-DSO (n = 19) or ventricular switch (n = 9). In 19 patients, a decompressing bidirectional cavopulmonary shunt was utilized, creating a reverse 1.5 switch. Median age at R-DSO/ventricular switch was 3.1 years (range, 9 months-12 years). At a median follow-up of 1.0 year (range, 38 days-7.2 years), no mortalities or heart transplants had occurred. Mild-moderate or greater RV dysfunction was detected in 4 patients, and mild-moderate or worse tricuspid regurgitation was also detected in 4 patients. Three patients required reoperations. Preoperative RV ejection fraction <55% was associated with higher incidence of postoperative RV dysfunction.

CONCLUSIONS

The R-DSO/VS strategy is an alternative to single-ventricle palliation or anatomic biventricular repair in the borderline left heart. Concerns for RV dysfunction and tricuspid regurgitation mandate close monitoring. Patients with preoperative RV dysfunction may be at risk for postoperative RV dysfunction. Further studies with longer follow-up are needed to delineate outcomes in comparison to the Fontan pathway and identify optimal candidates for this novel strategy.

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.

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.

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

OBJECTIVE

A subset of patients with borderline hypoplastic left heart may be candidates for single to biventricular conversion, but long-term morbidity and mortality persist. Prior studies have shown conflicting results regarding the association of preoperative diastolic dysfunction and outcome, and patient selection remains challenging.

METHODS

Patients with borderline hypoplastic left heart undergoing biventricular conversion from 2005 to 2017 were included. Cox regression identified preoperative factors associated with a composite outcome of time to mortality, heart transplant, takedown to single ventricle circulation, or hemodynamic failure (defined as left ventricular end-diastolic pressure >20 mm Hg, mean pulmonary artery pressure >35 mm Hg, or pulmonary vascular resistance >6 international Woods units).

RESULTS

Among 43 patients, 20 (46%) met the outcome, with a median time to outcome of 5.2 years. On univariate analysis, endocardial fibroelastosis, lower left ventricular end-diastolic volume/body surface area (when <50 mL/m2), lower left ventricular stroke volume/body surface area (when <32 mL/m2), and lower left:right ventricular stroke volume ratio (when <0.7) were associated with outcome; higher preoperative left ventricular end-diastolic pressure was not. Multivariable analysis demonstrated that endocardial fibroelastosis (hazard ratio, 5.1, 95% confidence interval, 1.5-22.7, P = .033) and left ventricular stroke volume/body surface area 28 mL/m2 or less (hazard ratio, 4.3, 95% confidence interval, 1.5-12.3, P = .006) were independently associated with a higher hazard of the outcome. Approximately all patients (86%) with endocardial fibroelastosis and left ventricular stroke volume/body surface area 28 mL/m2 or less met the outcome compared with 10% of those without endocardial fibroelastosis and with higher stroke volume/body surface area.

CONCLUSIONS

History of endocardial fibroelastosis and smaller left ventricular stroke volume/body surface area are independent factors associated with adverse outcomes among patients with borderline hypoplastic left heart undergoing biventricular conversion. Normal preoperative left ventricular end-diastolic pressure is insufficient to reassure against diastolic dysfunction after biventricular conversion.