Comparison of low molecular weight heparin vs. unfractionated heparin in gynecological surgery.

In a double-blind, randomized trial, the antithrombotic effect and haemorrhagic complications of low molecular weight heparin (LMWH) (Heparin fragment 2165, KabiVitrum) and unfractionated heparin (UH) were compared. LMWH (5000 anti-XaU) was injected every 24 h, UH (5000 IU) every 12 h; both drugs by subcutaneous injection. During 1984-85, 215 patients were examined clinically and by plethysmography. Venography was performed whenever DVT was suspected. None of the patients proved to have DVT. Bleeding complications were found in 54% of the cases. The LMWH group had a statistically significant predominance of bleeding complications as reflected by wound haematomas (p = 0.02) and the number of blood transfusions (p = 0.02). The heparin concentration was higher in the LMWH group (mean 0.13 IU/ml) than in the UH group (mean 0.13 IU/ml) measured 2 h after the injection. In the doses administered, LMWH and UH seem effective in the prevention of thrombosis. The increased bleeding tendency in the LMWH group probably was a consequence of the to high dosage.