Decreased thrombotic mortality and morbidity after valvular cardiac surgery as a consequence of adequate coumarin anticoagulation. A retrospective study in 516 patients.

ABSTRACT

Two almost identical groups of 258 patients each who underwent surgery for the substitution of one or more than one cardiac valve were taken into consideration. After surgery all patients, with the exception of those who received a porcine allograph, were given coumarin drugs for 1 year for thrombosis prophylaxis. In the first group of patients operated in 1972 and 1973 the laboratory follow-up and the therapeutic range were neither constant nor uniform. In the case of the second group, which included patients operated in 1974 and 1975, adequate laboratory follow-up and constantly adequate therapeutic ranges were always kept. This retrospective study has shown a statistically significant decrease in mortality due to thromboembolism and to unknown causes in the second group of patients (x2 = 8,313, "p" less than 0,0025). A decrease of the non-lethal embolic complications was also noted in the second group of patients (x2 = 6,813, "p" less than 0,0025). On the other hand, bleeding complications were greater in the second group of patients (x2 = 3,485, "p" less than 0,05) and this was interpreted as secondary to the higher anticoagulation administered to the latter patients. The results indicate that an adequate coumarin anticoagulation seems able to decrease the incidence of lethal or non-lethal thromboembolic complications after cardiac valve replacement significantly.