[Report of a case with re-mitral valve replacement for Björk-Shiley Delrin disc valve prosthesis--disc wear of the Delrin disc 20 years after implantation].

: We reported a patient in whom slight congestive heart failure gradually developed 20 years after mitral valve replacement with a Delrin disc Bjork-Shiley valve prosthesis. Although no evident cause of prosthetic valve malfunction could be detected preoperatively, the mitral prosthesis was excised and replaced uneventfully with a 29 mm St. Jude Medical valve prosthesis. At gross inspection, marked wears of the Delrin disc surface and strut shaped indentations were present. These disc variance, occurred much earlier than initially predicted by Dr. Bjork, allowed prosthetic valve malfunction. The patient with this specific model should be carefully followed-up, if necessary, performed reoperation.