Thrombosed Björk-Shiley standard disc mitral valve prosthesis.

Between April 1980 and June 1986, 274 patients underwent mitral valve replacement (MVR) with the Björk-Shiley (BS) standard disc mitral valve prosthesis at the American University of Beirut Medical Center (AUBMC). Eleven patients (3.9%) presented 6-41 months after surgery with prosthetic valve dysfunction due to thrombosis. Inadequate control of anticoagulation was the major factor predisposing to thrombosis in all except one. All patients had documented rheumatic valvular disease. Nine patients were operated on an emergency basis and two died before any surgical intervention was possible. Thrombectomy was performed on six patients with four survivors and MVR in three with two survivors. Two patients died intraoperatively (22%). Three pregnant patients underwent mechanical declotting; pregnancy was terminated by abortion in 2 and by caesarean section and live birth in one. We conclude that implantation of the BS mitral valve prosthesis mandates emphasis on anticoagulation and the difficulty encountered with continuous anticoagulant therapy in pregnancy.