Prophylaxis of fatal pulmonary embolism in general surgery using low-molecular weight heparin Cy 216: a multicentre, double-blind, randomized, controlled, clinical trial versus placebo (STEP). STEP-Study Group

The effectiveness of low-molecular weight heparin CY 216 in the prophylaxis of fatal pulmonary embolism in patients undergoing general surgery was assessed in a multicentre, double-blind, randomized, clinical trial against placebo. A total of 4,498 patients aged over 40 undergoing general surgery were enrolled in the 18 centres which took part in the trial. Patients received a single daily subcutaneous injection of 7,500 anti-Xa units I.C. of CY 216 or placebo two hours before surgery, 12 hours after the initial injection and then daily for at least seven days. A post-mortem examination had to be carried out in every patient who died. The two groups of patients were well-matched for age, sex, type of disease, site and duration of operation as well as for incidence of risk factors which could predispose to the development of thromboembolism. Twenty-six deaths were recorded and validated: eight (0.36%) in the CY 216 group and 18 (0.80%) in the placebo group (p less than 0.05). At the post-mortem examination, carried out in 23 patients (88.5%), two deaths were found to be directly due to pulmonary embolism (0.09%) in the CY 216 group and four (0.18%) in the placebo group. Pulmonary embolism contributed to death in four other placebo-treated patients. Pulmonary or extrapulmonary thromboembolism was a significantly less frequent direct cause of death (p less than 0.05) in the CY 216 group (two pulmonary embolisms) than in the placebo group (four pulmonary embolisms, one acute myocardial infarction, one disseminated intravascular coagulation, two ischemic cerebral strokes).(ABSTRACT TRUNCATED AT 250 WORDS)