The long-term results and changing patterns of biological valves at the mitral position in contemporary practice in Japan.

Mitral valve surgery has changed with the wide acceptance of mitral valve repair. The aim of this study is to obtain the long-term results of patients who underwent mitral valve replacement (MVR) using a biological prosthesis in contemporary practice in Japan. From January 1990 to December 2013, 76 patients underwent MVR using a biological prosthesis with or without concomitant surgery. Data were obtained by means of a questionnaire and a telephone interview. The mean follow-up period was 4.26 years. The etiologies of the patients included dilated cardiomyopathy (DCM) (n=20 [26.3%]), ischemic mitral regurgitation (n=7 [9.2%]). There is a trend towards decreasing number of rheumatic and degenerative disease and increasing number of DCM and ischemic mitral regurgitation. Three patients (3.9%) died in the perioperative period. The 5- and 10-year overall survival rates were 69.6% and 31.7%, respectively. The 5- and 10-year freedom from valve related death were 95.6% and 80.6 %, respectively. The linearized rates of valve-related complications were as follows: thromboembolism (0.63%/patient/year), bleeding (1.25%/patient/year). One patient underwent reoperation for structural degeneration 13 years after the first operation. The present study shows the long-term results of mitral valve replacement with bioproshtesis in a contemporary case series. The practice pattern is changing. The low rate of valve-related complication justify the current patient selection.