Current status of the mechanical valve and bioprosthesis in Japan.

The American College of Cardiology/American Heart Association guidelines for the management of patients with valvular heart disease were revised in 2006. These guidelines are introduced in this review, and the current status of the mechanical valve, bioprosthesis, and treatment of valvular heart disease are described based on the new guidelines as compared with the guidelines of 1998. The trend in valve selection in aortic valve replacement in the United States has been toward bioprosthesis, away from the mechanical valve. The reasons are: 1) current bioprostheses appear to have lower rates of structural valve deterioration, 2) the risks of reoperation have continued to decrease, 3) patients undergoing AVR today represent an older population than those in studies in randomized trials, 4) young patients undergoing AVR are often reluctant to accept warfarin therapy, 5) some large comparative trials have shown apparent survival benefit for patients receiving bioprostheses. In Japan, the use of tissue valves has been increasing and may continue to increase owing to the nation's aging population and to the reasons mentioned above. However, more patients received mechanical valves than bioprostheses for mitral valve replacement both in the United States and in Japan. The number of mitral valve repair cases has increased more than that of valve replacement. In selection of valve prosthesis for valve surgery, it is important that patients should decide by themselves based on mutual respect and trust between patient and doctor, with thorough discussion of the possibility of redo surgery and its risks, life-long warfarin intake, quality of life, and the patient's lifestyle and outlook on life.