Occurrence, diagnosis and treatment of thromboses of heart valve prostheses.

In the period from 1978 to 1985, the authors implanted a total of 667 Björk-Shiley heart valve prostheses. In the same period, they performed 6 times reoperation for thrombosis of these valves. There was one reoperation for thrombosis per 271 years of life with a valve prosthesis, i.e. 0.36% per patient year. All 6 reoperations were successful and there was until now no recurrence of thrombosis in any of the reoperated patients. All cases involved were thrombosis of the flat disc Björk-Shiley valve. There was now no thrombosis of convexo-concave types, which the authors have been using since 1981. The most important preventive measure against the development of thrombosis is strict observance and control of anticoagulation regimen. Thrombosis of a disc valve prosthesis can in most cases be diagnosed on the basis of the clinical picture and X-ray evidence of restricted disc mobility. Diagnosis of thrombosis is an indication for urgent reoperation, which is preferred to an uncertain attempt at thrombolysis.