Ten years of concomitant aortic and mitral replacement: trends, outcomes and the role of patient–prosthesis mismatch

Background Contemporary data comparing double mechanical prostheses (DMP) vs. double biological prostheses (DBP) for concomitant aortic and mitral valve replacement are scarce, and the cumulative hemodynamic burden of simultaneous prosthesis–patient mismatch (PPM) at both positions has never been systematically assessed. Results DMP recipients had lower in-hospital mortality (1.9% vs. 15.2%; P = 0.010) and superior 7-year survival (91.3% vs. 67.7%; P = 0.003), but significantly higher stroke rates (32.2% vs. 5.0%; P = 0.023). Combined PPM occurred in 64.6% of DBP vs. 14.8% of DMP ( P < 0.001). Major findings Concomitant double valve replacement confirmed its high-risk profile, with an overall in-hospital mortality of 10.5%. DMP demonstrated superior unadjusted survival (7-year: 91.3% vs. 67.7%; P = 0.003) but significantly higher stroke risk (32.2% vs. 5.0%; P = 0.023), without differences in major bleeding rates at follow-up (8.2% vs. 11.3%; P = 0.478), although baseline differences precluded definitive prosthesis-type recommendations after multivariable adjustment. Combined PPM is highly prevalent after DBP (64.6%) and emerged as a univariable mortality predictor (hazard ratio 1.97; P = 0.046); given the exploratory nature of the cPPM definition and its collinearity with prosthesis type, this should be regarded as hypothesis-generating and warrants validation in larger, ideally multicenter, cohorts.