Midterm Results of the Bioprosthesis in Mitral Position

Cho, Hyun Jin; Lee, Jae Won; Jung, Sung Ho; Je, Hyoung Gon; Choo, Suk Jung; Song, Hyun; Chung, Cheol Hyun

Abstract

BACKGROUND: The choice between a bioprosthetic and a mechanical valve is an important decision in cardiac valve surgery, and the durability of the tissue valve is a major decision factor. We retrospectively evaluated the midterm results of bioprosthetic valve replacement in the mitral position. MATERIAL AND METHOD: The subjects were all patients who had undergone mitral bioprosthesis replacement between July 1989 and August 2007. Among the 216 patients, there were 236 surgical cases. The mean age was 63+/-15 years, and the male to female ratio was 1:3. We retrospectively analyzed hospital and outpatient records such that the total follow-up duration amounted to 760.2 patient-years, and the mean follow-up duration was 41.9+/-40.7 months (range 0~212 months). RESULT: Early death occurred in 18 patients (8.3%), and 13 of these underwent concomitant cardiac procedures. The survival rate after 5 years was 79.9+/-3.5%, and the survival rate after 8 years was 65.5+/-5.5%, while freedom from structural valve deterioration (SVD) was 96.2+/-2.2% at 5 years and 85.9+/-5.3% at 8 years. Freedom from reoperation was 96.0+/-1.7% at 5 years and 90.4+/-4.2% at 8 years, while freedom from reoperation for SVD was 98.1+/-1.2% at 5 years and 92.3+/-4.1% at 8 years. On multivariate analysis of preoperative risk factors, small valve size (between 25 mm and 27 mm) was a significant risk factor for reoperation, and low LV ejection fraction (<40%) was a significant risk factor for SVD and mortality. CONCLUSION: Survival and freedom from reoperation for SVD in mitral bioprosthesis replacement had acceptable midterm results, but freedom from SVD was relatively low. In particular, since SVD increased sharply at the eighth postoperative year, frequent follow-up and echocardiograms around that time will be helpful for the early detection of SVD. It will be necessary to conduct further studies involving long-term follow-up and more patients.