This study was designed to evaluate the efficacy of carefully controlled treatment
with oral anticoagulants in patients with different mechanical heart valve prostheses.
One hundred eighty-one patients with various types of prosthetic valves (mitral 89,
aortic 87, combined 5) received oral anticoagulation aiming at Thrombotest (TT) values
between 5 % and 12 %. Median follow-up was 46 months; 80.8 % of all TT determinations
were below 12 %. The thromboembolic rate was 0.25 %/year in patients with aortic valve
replacement (AVR) and 4.87 %/year in patients with mitral valve replacement (MVR).
There was a strikingly lower incidence of thromboembolism with newer types of valves
(Björk-Shiley convex-concave) in the mitral position under exactly the same intensity
and stability of anticoagulant treatment. Clinically overt valve occlusion could be
almost completely prevented (0.12 %/year) in prostheses at both sites. Severe hemorrhage
occurred at a rate of 1.71 %/year and fatal bleeding at a rate of 0.37 %/year. Our
results indicate that carefully controlled anticoagulation is effective in the reduction
of thromboembolic complications at a reasonable risk of bleeding.
Thromboembolism - Prosthetic heart valves - Anticoagulation
