Management of zone of apposition in parachute left atrioventricular valve in atrioventricular septal defect

Background: The management of the zone of apposition (ZOA) in patients with atrioventricular septal defect (AVSD) and parachute left atrioventricular valve (LAVV) is controversial. Methods: Between 1977 and 2010, 28 patients with parachute LAVV associated with AVSD were reviewed. The median age at operation was 10 months (range, 36 days to 14 years). Sixteen (57%) patients had complete AVSD and 12 (43%) had partial AVSD. Thirteen (46%) patients had moderate to severe LAVV regurgitation. Results: The ZOA was managed with complete closure in 6 (22%), partial closure in 10 (36%), and no closure in 11 (39%) patients One patient underwent LAVV replacement for dysplastic leaflets. Dismissal echocardiogram demonstrated moderate LAVV regurgitation in 10 (36%) patients; 7 patients had no closure of ZOA, and 3 had partial closure. Mild or moderate LAVV stenosis was present in all 6 patients with complete closure of ZOA and 1 patient with partial closure. Median follow-up was 9 years (maximum, 22 years). Eight patients had progression of LAVV regurgitation through the unsutured ZOA; 6 patients subsequently underwent LAVV replacement. Of the 7 patients who had LAVV stenosis, 1 patient required opening of ZOA 1 month after surgery. The other 6 patients had a decrease in mean gradient. There was 1 late death after the fourth redo LAVV replacement. Conclusions: Progression of LAVV regurgitation from the unsutured ZOA was the main indication for reoperation in parachute LAVV with AVSD. The ZOA in parachute LAVV should be partially or completely closed at the time of AVSD repair. Although mild LAVV stenosis appeared to improve with time, life-long surveillance is essential.