[Prevention of thrombosis in gynecology: double-blind comparison of low molecular weight heparin and unfractionated heparin]

Abstract

The safety and efficacy of low molecular heparin (Sandoz AG, Nürnberg), given 1500 aPTT once daily (and two placebo injections), in preventing postoperative venous thromboembolism, was assessed against sodium heparin at a dose of 5000 IU three times daily, in a unicenter double-blind randomized study. 300 patients, scheduled for major gynecological surgery, were included in this study. Two patients (1.3%) of 150 patients developed deep vein thrombosis in the LMWH-group, the corresponding figure for sodium heparin was 6 patients (4.0%). There was no statistically significant difference between the two groups in respect to the bleeding variables such as postoperative drainage, blood transfusions and haematoma. The antithrombotic effects were assessed with the anti-Xa assay and LMWH-fractions have shown a high antifactor Xa/activated partial thromboplastin time (aPTT) specific activity (2:1) compared to unfractionated heparin (1:1). It is concluded that one single daily injection of LMWH (without dihydergot) provides a convenient safe and effective prophylaxis against thromboembolism in gynecological surgery.