Evaluation of bioprosthetic mitral valve failure.

: Porcine bioprosthetic heart valves have been in use for the past 13 years. Although they are superior to mechanical valves in several clinical situations, their long-term durability remains in question. The slight increase in failure rate of the bioprosthetic valve starting about six years after implantation mandates close follow-up of these patients. Since primary care physicians often provide most of the medical care to patients who have undergone heart valve replacement, it is important that they recognize the signs of bioprosthetic valve failure.