Sudden hemolysis indicating prosthetic valve dysfunction.

Ten months after aortic valve replacement (Björk-Shiley prosthesis) a 57-year-old man had thrombotic encapsulation of his prosthetic valve. The only clinical manifestation of this serious complication was gross hemoglobinuria. The management of the patient is described. The slightest change in the condition of a patient after prosthetic valve replacement should be viewed as a possible sign of thrombosis.