[Late malfunction of the Björk-Shiley valve prosthesis due to Delrin disc defacement].

A 55-year-old woman eighteen years after mitral valvular replacement with Delrin disc Björk-Shiley valve prosthesis underwent a reoperation of prosthetic valve replacement for the prosthetic malfunction due to disc defacement. The patient suffered from faintness and vertigo at rest. An echocardiographic examination showed a moderate mitral insufficiency with a normal disc movement. Precise examination on the removed prosthesis revealed accelerated defacement of disc margin which made the ring-disc clearance up to 0.35 mm and strut-shaped groove formation on the inlet surface of the disc occluder. These findings suggested a pronouncedly earlier disc wear than predicted by Björk and co-workers. We concluded, therefore, that a patient undergone a valve replacement with Delrin disc Björk-Shiley valve should be examined periodically by echocardiography even though being without any symptoms.