Does prosthesis-patient mismatch (EOA/BSA <0.75 cm2/m2) increase mortality in patients undergoing aortic valve replacement with stented bioprostheses?
Prosthesis-patient mismatch (EOA/BSA <0.75 cm2/m2) is associated with significantly higher early operative and late valve-related mortality after bioprosthetic aortic valve replacement.
BACKGROUND: Surgeons traditionally avoid the use of "small" aortic prostheses because of the potential for residual left ventricular outflow tract obstruction and persistent transvalvular gradients. This study examines the ratio between prosthetic valve size and the body surface area (BSA) of patients undergoing aortic valve replacement (AVR). We sought to determine the effect of potential "prosthesis-patient" mismatch on long-term survival. METHODS AND RESULTS: Follow-up was conducted on 2981 patients who underwent AVR with stented bioprostheses between 1976 and 1996. To account for differences between manufacturers' labeled valve sizes, we calculated the ratio between the prosthetic valve effective orifice area (EOA) and the patient's BSA (recorded for 2154 patients). The lowest decile in this cohort had a calculated EOA/BSA of 0.75 cm(2)/m(2). Operative mortality was higher in the Small group (8% versus 5%, P:=0.03). Actuarial survival at 12 years was 50+/-5% in the Small group compared with 49+/-2% in the control group (P:=0.27). However, freedom from valve-related mortality was significantly lower in the Small group (75+/-5% versus 84+/-2%, P:=0.004). Cox regression analysis determined age and NYHA functional class to be the multivariate predictors of overall mortality, whereas advanced age and EOA/BSA 0.75 cm(2)/m(2) may avoid residual left ventricular outflow tract obstruction and persistent transvalvular gradients. Careful prosthesis-patient matching will improve both early and late survival after AVR.
Rao et al. (Tue,) studied this question.