Two-ventricle repairs in the unbalanced atrioventricular canal defect spectrum with midterm follow-up.

Objectives: Unbalanced atrioventricular (AV) canal defects include a hypoplastic ventricle (HV) and AV valve (HAVV) precluding complete 2-ventricle repairs (2VRs). Catch-up growth would solve this problem and was induced by increasing HAVV flow. The objectives were to assess reliability of HV and HAVV growth and provide 5- to 15-year 2VR follow-up.

Methods: From 1990 to 2005, 23 consecutive infants (13 females and 10 males) with echo-diagnosed unbalanced AV canal defects (n = 20) or subsets (n = 3) underwent 2VRs. HV volumes (18 left and 5 right) and HAVV sizes estimated from biplane echoes and z values (standard deviation from expected) were determined. Hypoplasia was defined by a z value of less than -2.0. Three operative approaches were used: (1) Staged repairs (n = 9) had complete AVV repairs with partial atrial septal defect and ventricular septal defect closures, which increased HAVV flow and maintained stability. The septal defects were closed later. (2) An asymmetric valve partition (n = 8) was used to increase HAVV size. (3) For moderate hypoplasia, HAVV flow was increased and ASDs/VSDs were left for stability (n = 6). Follow-up at 5 to 19 years was done locally.

Results: Staged repairs began at 20 to 328 days (average, 129 days) and were completed 5 to 145 days later (average, 101 days). Midterm survival was 87% (20/23) after 1 central nervous system bleed after trial weaning from extracorporeal membrane oxygenation and 2 later deaths from hyperkalemia. Reoperations for AVV regurgitation (n = 3), AVV stenosis (n = 1), and mitral valve replacement (n = 1) were satisfactory. On follow-up, all hypoplastic structures (HV and HAVV) had grown to normal size. Two patients "doing well" were lost to follow-up. Survivors have satisfactory 2VRs, with 15 of 18 taking no cardiac failure medications.

Conclusions: Reliable HV/HAVV catch-up growth was induced, and all midterm 2VRs were satisfactory.