['Previous studies have shown that prosthesis-patient mismatch (PPM) results in higher early and late mortality after bioprosthetic aortic valve replacement. Careful selection of stented bioprostheses was recommended to avoid inadequate effective orifice area. We studied the incidence of PPM and its potential effects on clinical outcome in patients undergoing aortic valve replacement using the Carpentier-Edwards Perimount bioprosthesis.', 'Independent predictors of early and late mortality and hospital readmission for cardiac reasons were defined in 506 patients (mean age, 73 years; range, 57 to 87 years) by multivariate analysis. Mean follow-up was 6.1 +/- 4.8 years; maximum follow-up was 18.6 years.', 'The incidence of severe PPM (effective orifice area index < 0.65 cm2/m2) was 0.2% and of moderate PPM (effective orifice area index > 0.65 and < 0.85) was 20%. Multivariate analysis revealed that moderate PPM was not an independent predictor of early mortality, late mortality, or hospital readmission for cardiac reasons. Reduction of septal hypertrophy was similar in patients with and without moderate PPM.'] Is prosthesis-patient mismatch clinically relevant in aortic valve replacement using the Carpentier-Edwards Perimount valve?