Abstract 3172: Impact of Prosthesis-Patient Mismatch on Long-Term Survival After Aortic Valve Replacement

Abstract

Background: We recently reported that Prosthesis-Patient Mismatch (PPM) is an independent predictor of operative mortality in patients undergoing aortic valve replacement (AVR). The objective of this study was to evaluate the impact of PPM on late postoperative survival. Methods and Results: Between 1992 and 2005, 2653 patients (age: 68±10 years; 61% of males) underwent AVR in our institution. Patients who died at the time of operation or within 30 days were excluded from this study. The projected indexed effective orifice area (EOAi) was derived from the published normal in vivo EOA values for each model and size of prosthesis and PPM was classified as severe if the EOAi was ≤0.65 cm 2 /m 2 , moderate if it was > 0.65 cm 2 /m 2 and ≤ 0.85 cm 2 /m 2 , or not clinically significant if >0.85 cm 2 /m 2 . PPM was severe in 40 patients (2%), moderate in 797 (31%), and not significant in 1739 (67%). Patients with severe PPM had higher proportion of female gender (67% vs. 38%; P=0.0002) and hypertension (68% vs. 55%, p=0.02) and larger body surface (1.86±0.25 vs. 1.77±0.20, p=0.02). For patients with severe PPM, 5-year survival rate (74±8%) and 10-year survival rate (40±10%) were significantly (p=0.008) less than for patients with moderate PPM (5-yr: 81±2% and 10-yr: 57±3%) or no significant PPM (5-yr: 84±1% and 10-yr: 61±2%). On multivariate analysis after adjustment for other predictors of outcome, severe PPM was associated with increased overall mortality (Hazard ratio 1.38, [95% Confidence Interval 1.04 –1.75]; (p=0.02) Conclusion: In our previous study, we reported that severe PPM is a powerful risk factor for operative mortality. The results of the present study now suggest that severe PPM is also an independent predictor of long-term mortality. Hence, for the patients who are identified to be at risk of severe PPM at the time of operation, every effort should be made to implant a prosthesis with a larger EOA. Funded by: Canadian Institutes of Health Research