Impact of Prosthesis-Patient Mismatch on Long-term Functional Capacity After Mechanical Aortic Valve Replacement

Abstract

Background: The impact of prosthesis-patient mismatch (PPM) after aortic valve replacement (AVR) for aortic stenosis on exercise capacity remains controversial. The aim of this study was to analyze the long-term impact of PPM after mechanical AVR on maximal oxygen uptake (VO_2max).

Methods: The study included 75 patients who had undergone isolated mechanical AVR for aortic stenosis with normal left ventricular (LV) function between 1994 and 2012. Their functional capacity was evaluated on average 4.6 years after AVR by exercise testing, including measurement of their VO_2max, and by determining their New York Heart Association functional class and Short Form-36 score. Two groups were defined by measuring the patients' indexed effective orifice area (iEOA) by transthoracic echocardiography: a PPM group (iEOA < 0.85 cm²/m²) and a no-PPM group (iEOA ≥ 0.85 cm²/m²).

Results: PPM was present in 37.0% of the patients. The percentage of the predicted VO_2max achieved was significantly lower in the PPM group (86.7 ± 19.5% vs 97.5 ± 23.0% in the no-PPM group; P = 0.04). Compared with the no-PPM group, the PPM group contained fewer patients in New York Heart Association functional class I and their mean Short Form-36 physical component summary score was significantly lower. The mean transvalvular gradient was significantly higher in the PPM group than in the no-PPM group (P < 0.001). Systolic and diastolic function and LV mass had normalized in both groups.

Conclusions: PPM is associated in the long term with moderate but significant impairment of functional capacity, despite optimal LV reverse remodelling and normalization of LV systolic and diastolic function.