Comparative Durability of Porcine and Bovine Mitral Valve Bioprostheses

The objective of this study was to compare the durability of bovine pericardial and porcine bioprostheses in patients who underwent surgical mitral valve replacement.

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.

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).

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.