Biventricular repair in children with atrioventricular septal defects and a small right ventricle: anatomic and surgical considerations.

Objective: We sought to characterize morphology and to evaluate a strategy of using biventricular repair in patients with a small right ventricle and an unbalanced atrioventricular septal defect.

Methods: Thirty-eight children with a small right ventricle and an atrioventricular septal defect underwent operative therapy. Thirty-two had biventricular repair, and 6 had single-ventricle palliation. A small right ventricle was defined on the basis of echocardiographic measurements expressed as the atrioventricular valve index (ie, right atrioventricular valve/left atrioventricular valve area) and as the ratio of right ventricular to left ventricular length. Validation of measurements in patients with a small right ventricle and an atrioventricular septal defect was achieved by comparison with balanced case-matched control subjects with atrioventricular septal defects.

Results: Children with a small right ventricle and an atrioventricular septal defect had a lower atrioventricular valve index (mean, 0.41 +/- 0.1 vs 0.52 +/- 0.1 [control], P < .0001) and lower right ventricular/left ventricular length ratio (0.78 +/- 0.1 vs 0.99 +/- 0.17 [control], P < .0001). Children with a small right ventricle undergoing single-ventricle palliation had the smallest right ventricular dimensions. There were 4 operative deaths. Three patients with a small right ventricle and an atrioventricular septal defect who underwent biventricular repair and had an atrioventricular valve index of less than 0.50 required early reoperation for right ventricular inadequacy. A restrictive atrial fenestration was created in 11 infants. Survival at 10 years was 87% for patients undergoing biventricular repair versus 100% for control subjects (P = .042).

Conclusions: Extending the use of biventricular repair in properly selected patients with a small right ventricle and an atrioventricular septal defect is feasible. An atrial fenestration improves the physiologic tolerance to repair in selected patients. The use of biventricular repair in children with atrioventricular valve indexes of less than 0.50 requires caution.