Abstract 2863: Patient-Prosthesis Mismatch is Associated with Reduced Mid-Term Survival after Aortic Valve Replacement
There has been ongoing controversy as to whether patient-prosthesis mismatch (PPM), defined as an indexed effective orifice area (EOAI)< 0.85cm2/m2, influences mortality after aortic valve replacement (AVR). In most studies, as opposed to directly measured PPM is anticipated by reference tables based on mean effective orifice areas. These reference values may not reflect the actual in-vivo EOAI preventing accurate determination of the presence or absence of PPM. 521 patients (mean age 72.3±7.6y) following AVR between August 2000 and February 2007 entered the study. All patients underwent transthoracic echocardiography for determination of the actual and not referenced EOAI within six months postoperatively. In order to predict time from surgery to death (overall survival) we employed Cox proportional hazards regression. EOAI was entered as a continuous variable and adjusted for age, gender and clinically relevant variables. PPM (EOAI≤0.85cm2/m2) occurred in 40% of the patients. After a median FU of 2.3yrs, 94.4% of the patients were alive. Our final Cox regression model provides evidence of a decreased mortality risk among patients with a larger EOAI (HR = 0.273, p = 0.076). The effect of EOAI on mortality risk for a selected profile of patients is illustrated in figure 1⇓. In contrast to previous studies our EOAI values were obtained through postoperative echocardiography, substantially improving the accuracy of measurement. There was a strong trend of improved survival for larger EOAIs following AVR. Strategies to avoid PPM, such as the use of third generation prostheses or annular enlargement, should become paramount during AVR.