Performance at 10 years of the CarboMedics "Top-Hat" valve. Postclamping time is a predictor of mortality.

OBJECTIVE: The CarboMedics "Top-Hat" supraannular prosthesis was designed to permit the implantation of a larger prosthesis. We evaluated the outcome at 10 years in patients with this prosthesis.

METHODS: Between June 1993 and May 2001, 269 patients (average age, 63.9 years) received a CarboMedics "Top-Hat" supraannular aortic prosthesis. Primary valve replacement was performed on 203 patients (75.5%) and repeat valve replacement on 66 (24.5%). The duration of myocardial ischemia was 70.2+/-31.4 min, cardiopulmonary bypass 96.1+/-48.3 min, and postclamping time (time between release of aortic clamp and the end of extracorporeal circulation) 22.1+/-41.3 min. The mean follow-up was 82.3+/-17.8 months. Follow-up was 97.6% complete.

RESULTS: The hospital mortality was 5.9%. It was 1% when the duration of postclamping time was <15 min, 2.8% between 15 and 29 min, 13.2% between 30 and 44 min, and 26.9% >44 min. In the multivariate analysis, postclamping time, urgent surgery, and body mass index were statistically significant risk factors for hospital mortality. The late mortality was 17.1%. Cardiac-related mortality showed a linearized rate of 18.1% per 1000 patients-year. The Kaplan-Meier estimates for cardiac-related mortality was 75.0% at 10 years. Postclamping time, aortic valve gradient, age over 70 years, and BMI were statistically significant risk factors for cardiac-related late mortality. The incidence of paravalvular leak in the "Top-Hat" aortic prosthesis was 1.7% per 1000 patients-year.

CONCLUSIONS: Using the CarboMedics supraannular prosthesis allows implantation of a larger prosthesis without increasing valve-related complications. Postclamping time appears as a strong predictor of both hospital mortality and late cardiac-related death.