Incidence, Predictors, and Outcomes of Patient-Prosthesis Mismatch After Surgical Aortic Valve Replacement

This study aimed to assess the incidence, predictors, and clinical outcomes of patient-prosthesis mismatch after surgical aortic valve replacement using the binational Australian and New Zealand Society of Cardiac and Thoracic Surgeons Database.

Data from all adult patients undergoing surgical aortic valve replacement between 2001 and 2021 across 58 participating hospitals in the Database were included. Effective orifice areas of the prosthetic valves were collected from the manufacturer's specifications and existing literature. Patient-prosthesis mismatch was classified by indexed effective orifice areas: no mismatch (>0.85 cm²/m²), moderate mismatch (0.66-0.85 cm²/m²), and severe mismatch (≤0.65 cm²/m²).

We included 36,150 patients in the study, of whom 19,330 (53.5%) had no mismatch, 15,405 (42.6%) had moderate mismatch, and 1,415 (3.9%) had severe mismatch. Predictors of mismatch included older age, larger body surface area, diabetes, hypertension, poorer New York Heart Association class, earlier year of operation, urgent operation, and use of bioprostheses. Patients with severe mismatch had the highest 30-day mortality (4.5%; moderate mismatch, 3%; no mismatch, 2.4%; p<0.0001). Both moderate and severe mismatch were associated with significantly increased long-term mortality (p=0.0003) and reduced long-term survival (log-rank p<0.0001).

Moderate patient-prosthesis mismatch is common following surgical aortic valve replacement. Older age, larger body surface area, diabetes, hypertension, poorer New York Heart Association class, earlier year of surgery, urgent operation status, and the use of bioprosthetic valves were associated with mismatch. Patient-prosthesis mismatch of any severity was associated with increased risk of short- and long-term mortality, and worse survival.