Objective: To determine the durability of repair of a bicuspid aortic valve with leaflet prolapse, and to identify factors associated with repair failure. Methods: From November 1988 to January 1997, 94 patients with a bicuspid aortic valve and regurgitation from leaflet prolapse had aortic valve repair. In 66 patients, the repair employed triangular resection of the prolapsing leaflet. The remainder underwent mid-leaflet plication of the prolapsing leaflet. Mean age was 38 +/- 10 years and 93% were male. Median follow-up was 5.5 years (range 0.2-9 years). Factors associated with aortic valve competence and durability were identified by multivariable logistic and hazard function analyses. Results: Early valve competence was more difficult to achieve in patients with large, poor functioning ventricles (P = 0.02). Aortic valve reoperation was necessary in 12 patients that included three re-repairs and nine aortic valve replacements. Freedom from reoperation was 95, 87 and 84% at 1, 5 and 7 years, respectively. The instantaneous risk of reoperation was highest immediately after operation, and fell rapidly to approximately 2% per year and less after 2 years. The only risk factor identified was the presence of residual aortic regurgitation (trace to mild in 35 cases) on immediate intraoperative post-repair transesophageal echocardiography. Late aortic regurgitation did not progress detectably across time (P = 0.3). There were no deaths, early or late. Conclusion: Bicuspid aortic valve repair for prolapsing leaflet is a safe procedure with good intermediate-term outcome. However, any residual aortic regurgitation jeopardizes repair durability and initial repair achievement is more difficult in patients with dilated, poor functioning ventricles. (C) 1999 Elsevier Science B.V. All rights reserved.