Patient-prosthesis mismatch in patients undergoing bioprosthetic aortic valve implantation increases risk of reoperation for structural valve deterioration.

Objective: Patient-prosthesis mismatch has been identified as a risk factor for mortality after aortic valve replacement and for structural valve deterioration (SVD) in patients receiving a bioprosthetic aortic valve. The aim of the present study was to compare the incidence of aortic valve bioprosthesis replacement for SVD in patients with mismatch to a population without mismatch.

Methods: Three hundred eighty-seven adult patients who underwent aortic valve replacement with a bioprosthesis from 1974 to 2009 were retrospectively reviewed. Mismatch was considered to be present if the anticipated indexed effective orifice area was <0.70 cm(2) /m(2) . The median follow-up period was 7.2 years. Follow-up was 97% complete.

Results: Patient-prosthesis mismatch was present in 12% of the study population (n = 47). Ten-year freedom from reoperation for aortic bioprosthesis replacement was 74.3 ± 3.2%. During follow-up, 111 patients underwent reoperation for aortic bioprosthesis replacement. Causes of aortic bioprosthesis replacement were SVD of the bioprosthesis (n = 96), paravalvular leak (n = 10), and acute endocarditis (n = 5). According to unadjusted Kaplan-Meier analysis, patients with mismatch had a higher incidence of aortic bioprosthesis replacement for SVD when compared with patients without mismatch (log rank test: p 0.05). This result was confirmed by multivariable Cox regression analysis, which identified two independent predictors of aortic bioprosthesis replacement for SVD: patients' age (hazard ratio (HR) 0.967) and patient-prosthesis mismatch (HR 2.161).

Conclusions: Patients suffering from mismatch were twice as likely to undergo reoperation for aortic bioprosthesis replacement for SVD than those without mismatch.