Biventricular Conversion After Single-Ventricle Palliation in Unbalanced Atrioventricular Canal Defects

Background Management of unbalanced common atrioventricular canal (UCAVC) defect by a single-ventricle (SV) approach frequently results in poor outcomes, especially in trisomy 21 patients. In this report we describe our results with conversion to biventricular circulation in UCAVC patients with SV palliation. Methods Retrospective review of patients with UCAVC undergoing biventricular conversion from prior SV palliation between 2003 and 2011 was conducted. Mortality and freedom from reinterventions were analyzed using nonparametric methods. Results Sixteen children with UCAVC (8 patients [50%] were left dominant) and prior SV palliation underwent conversion to biventricular circulation between 2003 and 2011. Median follow-up was 18 months (range, 3 to 94 months). Surgical indications included worsening cyanosis, severe atrioventricular valve regurgitation, or failing bidirectional Glenn or Fontan physiology. All patients had either unequal distribution of the common atrioventricular valve of greater than 60% or one hypoplastic ventricle. By magnetic resonance imaging or computed tomography, 8 patients with right dominant atrioventricular canal had a median left ventricular end-diastolic volume of 32 mL/m 2 (range, 22 to 35 mL/m 2 ). Eight patients with a left dominant atrioventricular canal had a median right ventricular end-diastolic volume of 42 mL/m 2 (range, 26 to 64 mL/m 2 ). Eleven patients (69%) had trisomy 21, and 3 patients (19%) had heterotaxy. Stages of palliation included stage I in 2 patients, bidirectional Glenn in 10 patients, hemi-Fontan in 2 patients, and Fontan in 2 patients. There was 1 (6%) operative (right ventricle dominant) and 1 (6%) late death (left ventricle dominant). Eight patients required reinterventions, 3 (19%) surgical and 6 (38%) catheter-based. On follow-up, all had improvement in cyanosis and symptoms. Conclusions Biventricular conversion from failing SV palliation in UCAVC can be accomplished with an acceptable early and late morbidity and mortality, although need for reintervention was not uncommon.