Prevention of venous thromboembolism in general surgery.

Venous thromboembolism continues to be an important cause of death in hospitalized patients undergoing major elective surgery. A study of autopsy-proven pulmonary embolism in hospital patients showed that venous thromboembolism accounted for 10% of deaths and that recognition of non-fatal thromboembolism continues to be a problem. The incidence of deep vein thrombosis increases with ageing, the annual rate per 1000 being one to three for those aged between 65 and 69 years and from two to eight for those aged between 85 and 89 years. The introduction of low-molecular-weight heparins has resulted in important changes in the management and prophylaxis of venous thromboembolism. Low-molecular-weight heparin preparations reduce the overall incidence of deep vein thrombosis in general surgery by at least 70%. Furthermore, the effect of low-molecular-weight heparin against pulmonary embolism is at least as great as that of low-dose unfractionated heparin. The incidence of serious and minor haemorrhagic events with low-molecular-weight heparin is similar to that with low-dose unfractionated heparin. Prophylaxis is started pre-operatively, and the usual duration for the post-operative period has been 7 days, or until the patient is discharged from the hospital. In conclusion, low-molecular-weight heparin is highly effective in preventing post-operative venous thromboembolism.