Risk factors for late left atrioventricular (AV) valve insufficiency, which occurred in 16 (18%) of 90 patients evaluated after repair of partial AV septal defect, were examined. The operative findings in 9 patients undergoing reoperation were also examined. Preoperative left AV valve insufficiency was significantly more common in the group with late left AV valve incompetence, as were associated valvular malformations as a whole and fenestrations of valve leaflets in particular. Conversely, the higher incidence of malformed or malpositioned papillary muscles, accessory clefts, and double-orifice left AV valves in the group with late left AV valve insufficiency did not reach significance. The method of surgical treatment of the septal commissure was not a significant factor. In the group having reoperation, additional valvular malformations were found in association with inappropriate treatment of the septal commissure in 7 patients. The 2 remaining patients had either a directly sutured ostium primum or dilatation of the annulus. Three re-repairs were successful. Five patients required prosthetic valve replacement. Preoperative left AV valve insufficiency and associated valvular malformations are major determinants of late left AV valve insufficiency in partial AV septal defect. © 1990.
