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 Conversion in Unseptatable Hearts: "Ventricular Switch"

Patients with complex systemic and pulmonary venous anatomy, common atrioventricular canal defects and conotruncal anomalies have traditionally been routed to univentricular palliation and labeled as "unseptatable." This report describes our initial experience in septation/biventricular conversion ("ventricular switch"), utilizing the left ventricle (LV) as the subpulmonary ventricle, essentially recapitulating the physiology of congenitally corrected transposition of the great arteries. Five consecutive patients with challenging anatomic configuration underwent septation. All patients were severely cyanotic and had important functional limitations. All patients required complex atrial septation. Ventricular septation was precluded by fixed pulmonary vascular resistance in 2 patients. Systemic venous return was diverted to the morphologic LV as part of physiological 2V (n = 4) or 1.5 V repair (n = 1). Median conversion age was 9 years (range 11 months-46 years). Four patients had 12 previous cardiac surgical procedures in preparation for univentricular repair elsewhere. Three dimensional-printed heart models evaluated feasibility of septation. All patients are alive at a median follow-up of 0.6 years (range 0.08-2.7 years). Median hospital stay was 13 (range 10-60) days. LV recruitment improved functional status and significantly increased systemic oxygen saturation in all patients (79 ± 7% vs 95 ± 5%, P = 0.003). We report a novel paradigm for successfully utilizing both ventricles with the morphologic LV as the subpulmonary ventricle, in a complex population thought to be unseptatable. This approach is versatile and can likely be extrapolated to other complex anatomic configurations. Although we utilized this strategy in patients of variable age, earlier ventricular switch may yield the best results.