Thromboembolic and haemorrhagic risk in mechanical and biological aortic prostheses

Thromboembolism, valve thrombosis and haemorrhagic events have been compared in 356 Starr-Edwards (SE) 1260, 133 Bjork-Shiley (BS), and 178 aortic bioprostheses operated upon between 1968 and 1982, and reviewed by the same group with less than 2% of patients lost to follow-up. Expressed in actuarial rate at 7 years the percentage of patients free of thromboembolism event is 87% for SE, 86% for BS, 94% for bioprostheses; the linearized rate is 2.9%/patient/year for SE, 2.2 for BS, 1.9 for bioprostheses (NS). Valve thrombosis was not observed in bioprostheses; 97.9% of patients with mechanical valves were free of valve thrombosis at 6.5 years. Haemorrhagic risk was lower with bioprostheses than with mechanical valves 0.2% patient/year vs 2.33 (P < 0.005). The most important factor influencing thromboembolic and haemorrhagic risks is the quality of anticoagulant therapy. Other contributing factors are the date of the operation and associated mitral disease.