Disc failure in a Björk-Shiley mitral prosthesis.

The case of a 50-year-old man is presented who underwent reoperation for a malfunctioning Björk-Shiley spherical valve which had been inserted 14 years previously. The patient made a satisfactory recovery after surgery. Examination of the explanted valve revealed that a segment of the pyrolytic carbon disc was missing. There was no evidence of embolization.