Low-molecular-weight Heparins for the Treatment of Venous Thromboembolism

Recent studies have indicated that certain low-molecular-weight heparins given subcutaneously may replace continuous intravenous unfractionated heparin for the treatment of venous thromboembolism. Low-molecular-weight heparins have a predictably high absorption rate when given subcutaneously and they do not require laboratory monitoring. These characteristics of low-molecular-weight heparin therapy raise the possibility of treating uncomplicated patients with deep venous thrombosis or pulmonary embolism in the outpatient setting. The advantages to the patient of avoiding in-hospital care and its associated hazards are obvious. Outpatient low-molecular-weight heparin will likely prove to be highly cost-effective. At the present time, the finding associated with an individual low-molecular-weight heparin preparation cannot be extrapolated to different low-molecular-weight heparins and each must be evaluated in separate clinical trials. Recent randomized clinical trials indicate that low-molecular-weight heparin may be safer and more effective than continuous intravenous unfractionated heparin in the treatment of proximal venous thrombosis. A decreased mortality rate, which was particularly striking in patients with metastatic carcinoma, was unexpected and requires confirmation in further prospective randomized trials.