Antimineralization treatment and patient-prosthesis mismatch are major determinants of the onset and incidence of structural valve degeneration in bioprosthetic heart valves

Background: We examined the influence of multiple valve-related parameters on the onset and incidence of valve degeneration in aortic bioprostheses through detailed echocardiographic follow-up. Methods: In 648 patients (mean age, 73.8 +/- 4.9 years) receiving an aortic valve bioprosthesis, long-term clinical (mean, 7.5 +/- 3.2 years) and echocardiographic (mean, 6.5 +/- 3.4 years) follow-up were performed. The occurrence of signs of structural valve degeneration (stenosis type and regurgitation type) was studied through multivariate analysis, including tissue origin, design and label size of the prosthesis, effective orifice area index (EOAi), patient-prosthesis mismatch (PPM; EOAi< 0.85 cm(2)/m(2)), and antimineralization treatment. Results: Structural valve degeneration (SVD) was diagnosed in 12.6% of patients. In 7.6%, it was of the stenosis type (S-SVD); in 5%, it was the regurgitation type (R-SVD). The absence of antimineralization treatment is an independent predictor of SVD, S-SVD, and R-SVD. Patient-prosthesis mismatch is an independent predictor of SVD and S-SVD, but not of R-SVD. Patients receiving a nontreated valve show a freedom of SVD at 10 years follow-up of 70.1 +/- 4.3% versus 90.9 +/- 3.6% in patients receiving a treated valve (P<. 0001). Patients having PPM and receiving a nontreated valve show a freedom of SVD at 10 years of follow-up of only 59.8 +/- 7.0% versus 88.7 +/- 3.6% in patients also having PPM but receiving a treated valve (P<. 0001). In patients not having PPM, the corresponding values were 78.0 +/- 4.3% and 92.7 +/- 3.4% for nontreated versus treated valves respectively (P=01). Conclusions: Antimineralization treatment of bioprosthetic heart valves is effective and reduces the incidence of SVD significantly. Because valve type and size are determined at the moment of implantation, the surgeon carries an important responsibility in protecting the patient from valve degeneration.