Prosthesis-Patient Mismatch After Aortic Valve Replacement: Effect on Long-Term Survival.

Background: Mean follow-up in previous studies on the effect of prosthesis-patient mismatch on long-term survival after aortic valve replacement (AVR) is confined to a maximum of one decade. This retrospective longitudinal cohort study was performed to determine the effect on long-term survival of prosthesis-patient mismatch after AVR with a mean follow-up of almost two decades.

Methods: Kaplan-Meier survival analysis was used to determine long-term survival after AVR in a cohort of 673 consecutive patients, divided into 163 patients (24.2%) with prosthesis-patient mismatch (indexed effective orifice area ≤ 0.85 cm(2)/m(2)) and 510 patients (75.8%) without prosthesis-patient mismatch (indexed effective orifice area >0.85 cm(2)/m(2)). Effective orifice area values of the prosthetic valves were retrieved from the literature or obtained from the charts of the prosthetic valve manufacturers. Cox multiple regression analysis was used to identify possible independent predictors, including prosthesis-patient mismatch, of decreased long-term survival.

Results: Median sizes of the implanted mechanical (n = 430) and biologic (n = 243) prostheses were 25 and 23 mm, respectively. Mean follow-up after AVR was 17.8 ± 1.8 years. Prosthesis-patient mismatch was not an independent predictor of decreased long-term survival (hazard ratio, 0.828; 95% confidence interval, 0.669 to 1.025; p = 0.083). Severe prosthesis-patient mismatch (indexed effective orifice area ≤ 0.65 cm(2)/m(2)), occurring in only 17 patients (2.5%), showed an insignificant trend toward decreased long-term survival (hazard ratio, 1.68; 95% confidence interval, 0.97 to 2.91; p = 0.066).

Conclusions: Prosthesis-patient mismatch was not an independent predictor of decreased long-term survival after AVR.