Low molecular weight heparin in prevention of perioperative thrombosis

• Published in: BMJ Vol. 305; no. 6859; pp. 913 - 920
• Main Authors: Leizorovicz, A., Haugh, M. C., Chapuis, F. R., Samama, M. M., Boissel, J. P.
• Format: Journal Article
• Language: English
• Published: London British Medical Journal Publishing Group 17-10-1992; British Medical Association; BMJ Publishing Group LTD
• Subjects: Biological and medical sciences; Bleeding; Blood Loss, Surgical; Blood. Blood coagulation. Reticuloendothelial system; Clinical trials; Dextrans; Dextrans - therapeutic use; Heparin; Heparin - therapeutic use; Heparin, Low-Molecular-Weight - therapeutic use; Humans; Incidence; Intraoperative Complications - epidemiology; Intraoperative Complications - prevention & control; Low molecular weights; Medical sciences; Meta analysis; Orthopedics; Pharmacology. Drug treatments; Placebos; Pulmonary Embolism - epidemiology; Pulmonary Embolism - prevention & control; Pulmonary embolisms; Thrombophlebitis - epidemiology; Thrombophlebitis - prevention & control; Thrombosis; Venous thrombosis; Human; Prevention; Chemotherapy; Orthopedic surgery; Treatment; Low; Cardiovascular disease; Anticoagulant; Heparin; Vein; Thrombosis; Molecular weight
• ISSN: 0959-8138; 0959-8146; 1468-5833; 1756-1833
• DOI: 10.1136/bmj.305.6859.913

OBJECTIVE--To determine whether prophylactic treatment with low molecular weight heparin reduces the incidence of thrombosis in patients who have had general or orthopaedic surgery. DESIGN--Meta-analysis of results from 52 randomised, controlled clinical studies (29 in general surgery and 23 in orthopaedic surgery) in which low molecular weight heparin was compared with placebo, dextran, or unfractionated heparin. SUBJECTS--Patients who had had general or orthopaedic surgery. INTERVENTION--Once daily injection of a low molecular weight heparin compared with placebo, dextran, or unfractionated heparin. MAIN OUTCOME MEASURES--Incidence of deep venous thrombosis, pulmonary embolism, major haemorrhages, and death. RESULTS--The results confirm that low molecular weight heparins are more efficacious for the prophylactic treatment of deep venous thrombosis than placebo (common odds ratio 0.31, 95% confidence interval 0.22 to 0.43; p < 0.001) and dextran (0.44, 0.30 to 0.65; p < 0.001). The results suggest that low molecular weight heparins are also more efficacious than unfractionated heparin (0.85, 0.74 to 0.97; p = 0.02), with no significant difference in the incidence of major haemorrhages (1.06, 0.93 to 1.20; p = 0.62). CONCLUSIONS--Low molecular weight heparins seem to have a higher benefit to risk ratio than unfractionated heparin in preventing perioperative thrombosis. However, it remains to be shown in a suitably powered clinical trial whether low molecular weight heparin reduces the risk of fatal pulmonary embolism compared with heparin.