Combined Aortic and Mitral Valve Replacement with the Björk-Shiley Tilting Disc Valve Prosthesis

Abstract

This study evaluates the early and late results of combined aortic and mitral valve replacement with the Björk-Shiley tilting disc valve prosthesis in 75 consecutive patients operated upon during a 6-year-period commencing October 1969. The Delrin disc model Björk-Shiley prosthesis was inserted in the first 20 patients and the pyrolytic carbon disc model in the remainder. The opening angle was increased from 50° to 60° and the Teflon sewing ring was designed with two flanges in the pyrolytic carbon disc mitral model. The patient material was characterized by marked cardiomegaly, impaired physical working capacity, hypokinetic central circulation, pulmonary hypertension and a 59% incidence of atrial arrhythmias before operation. Surgery was performed during generalized hypothermia to 30°C and selective coronary perfusion, and the mitral valve was always replaced first. There were no intra-operative deaths, although 7/75 patients (9%) died while in hospital. Twelve patients (16%) died in average 19 (2–59) months postoperatively. Thrombo-embolic complications, which were frequently associated with poor anticoagulation, occurred in 9 patients and were fatal in 4 cases, corresponding to an incidence per patient month of 0.005 and 0.002, respectively. This risk was not affected by the type of prosthesis. One patient required operative repair of an aortic paraprosthetic leakage. Clinical improvement was found in 88% of the long-term survivors. The maximal working capacity increased in average 41% over the pre-operative value (p < 0.001) and cardiac enlargement diminished in average by 22% (p < 0.001). The incidence of atrial arrhythmias decreased slightly to 48%. Haemolysis was mild and without clinical significance. The actuarial curve indicated a 75% survival rate 3 years after operation.