Aim
To analyse the factors affecting re-operation after primary bi-ventricular atrio-ventricular septal defect (AVSD) repair with focus on technical aspects.

Method
Between April 1997 and April 2007, 93 consecutive patients underwent surgery for bi-ventricular correction of AVSD (median age: 5.8 months (range 9 days–68.9 years) and median weight of 5.8 kg (range 2.6–81.0 kg). Fifty-three patients had complete AVSD, 6 patients an intermediate type, 29 patients partial AVSD, 4 patients with associated Tetralogy of Fallot and 1 with double outlet right ventricle. Nine patients were right ventricle dominant.

Results
There was no in-hospital mortality. There were 2 late deaths (2.2%). Actuarial survival at 10 years was 97.6%. Forty-three re-operations were performed in 23 patients (24.7%), of which 18 were for repair of significant left atrioventricular valve regurgitation (LAVVR) and 8 were mitral valve replacements. Seven patients (7.5%) required insertion of a permanent pacemaker. The overall 5-year and 10-year freedom from re-operation following AVSD repair was 75.5±4.8 % and 64.1±8.6%, respectively. In the multivariate analysis, presence of associated cardiac defects (p=0.016) and post-operative pulmonary hypertension (p=0.038) were independent predictors of re-operation. At last follow-up, 76 patients (87.4 %) were in NYHA class I and 68 patients (78.2 %) were on no heart failure medications. Echocardiographic examination showed absent to mild LAVVR in 76.5%, moderate in 19.8 % and severe in 3.7 % patients.

Conclusions
Associated cardiac defects and post-operative pulmonary hypertension increase the risk of re-operation after AVSD repair. In small left ventricles, biventricular repair can be accomplished with low mortality.