Comparative Durability of Porcine and Bovine Mitral Valve Bioprostheses

OBJECTIVE: The objective of this study was to compare the durability of bovine pericardial and porcine bioprostheses in patients who underwent surgical mitral valve replacement. METHODS: From 1/1/2000-1/1/2024, 6,515 adults underwent 6,789 mitral valve replacements with either porcine(n=4,597) or bovine(n=2,192) stented bioprostheses. Propensity score matching yielded 1,853 well-matched pairs. Durability was assessed by explant for structural valve deterioration(SVD) and longitudinal analysis of echocardiographic data(≥moderate mitral regurgitation and mean mitral gradient). Mortality and competing risks of explant for SVD and infective endocarditis were modeled using multiphase hazards. RESULTS: Bovine bioprostheses were more commonly used before 2010, and porcine more recently. Within the matched groups, 352 reinterventions were identified, primarily for SVD(70%; n=253) and endocarditis(19%; n=69). At 15 years, conditional probability of reintervention for SVD was 34% in the porcine versus 45% in the bovine group(early P=.61; late P=.003). The porcine group had an increased risk of reintervention for endocarditis in the first year(P=.046), but similar risk thereafter(P=.54). Risk of ≥moderate mitral regurgitation at 10 years was 3% among porcine and 12% among bovine bioprostheses(P<.0001), with higher mean gradients in the bovine group(6.6 mmHg vs. 8.2 mmHg; late P<.0001). Survival 15-years after porcine mitral valve replacement was 18%, compared to 22% after bovine(P=.21). CONCLUSIONS: The stent-mounted porcine bioprosthesis had better durability than the bovine bioprosthesis in the mitral position and is preferred over a bovine bioprosthesis with excellent late outcomes, particularly in patients under 60 years of age.