**11. Surgical outcomes**

Even though the outcomes for partial AVSDs are excellent, approximately 10–15% of patients require additional operations. It is well known that pre-operative left AV valve regurgitation predicts the post-operative severity of regurgitation. Other factors are severely dysplastic valve, failure to close the cleft, age of initial surgery, left AV valve stenosis and LVOT obstruction [41]. A technical performance score (TPS) was proposed to grade residual lesions after partial and transitional AVSD repair. In that study, left AV valve regurgitation was the strongest predictor of in-hospital outcomes and unplanned reinterventions after discharge [50]. When compared to complete AVSD, LVOT obstruction occurs more frequently after repair of partial AVSD. Several technical strategies were proposed to decrease the likelihood of subaortic stenosis [51–53].

In complete AVSDs, late reoperation occurs in around 11–20% of patients with most common reason being left AV valve regurgitation [54, 55]. In these studies, freedom from further reoperation after the first reoperation was 63%, 48%, and 42% at 5, 10, and 15 years, respectively. On later follow-up (median 10.7 years, maximum 30 years), actuarial overall survival was 91%, 91%, and 86% at 5, 10, and 15 years, respectively [55]. A recent study showed improved outcomes with overall survival at 10, 15 and 20 years was 91.7%, 90.7% and 88.7%, respectively and freedom from reoperation was 82.7%, 81.1% and 77%, respectively [56].
