Biventricular conversion after single ventricle palliation in patients with small left heart structures: short-term outcomes

Background: Patients with borderline small left heart (LH) structures who initially undergo single ventricle palliation (SVP) may eventually become candidates for biventricular conversion (BC). The purpose of this study was to describe our surgical experience with BC in patients with small LH.

Methods: We reviewed our institution's records for patients who underwent BC after an initial SVP between 1995 and 2012. Patients underwent an aortopulmonary amalgamation procedure as a part of their initial palliation. Data on imaging, BC operative details, and re-interventions after BC were collected.

Results: Twenty-eight patients underwent BC. Twenty patients had hypoplastic left heart syndrome (HLHS), 7 patients had unbalanced common atrioventricular canal (uCAVC), and 1 had interrupted aortic arch with VSD. Stage of palliation at BC was stage 1 in 6 patients (21.4%), bidirectional Glenn in 19 (67.9%), and Fontan in 3 (10.7%). Prior to BC, the median left ventricular end-diastolic volume (LVEDV) by echocardiography was 58.1 mL/m(2) in the HLHS group and 28.1 mL/m(2) in the uCAVC group. After BC, the LVEDV increased to 91.3 mL/m(2) in the HLHS group and 58.5 mL/m(2) in the uCAVC group (p < 0.05 compared with pre-BC in both groups). Right ventricular pressure was less than half systemic in 8 patients (53.3% of those measured). Seventeen patients (61%) have required either catheter-based or surgical re-intervention. Twenty-five patients (89.3%) were alive at a median follow-up of 2.6 years.

Conclusions: Biventricular conversion can be applied to patients with HLHS and uCAVC and borderline LH with acceptable short-term results. Left heart size increases after BC, but follow-up for potential left atrial hypertension is warranted.