Low-Molecular-Weight Heparin Therapy and Mortality

There is ample evidence from clinical trials to justify giving certain low-molecular-weight heparins (LMWHs) subcutaneously rather than administering continuous intravenous unfractionated heparin for the initial treatment of venous thromboembolic disease. The LMWHs given by subcutaneous injection have a predictable anticoagulant response and prolonged duration of action. They can, therefore, be administered once or twice daily to treat venous thrombosis. Furthermore, treatment with these agents does not require laboratory monitoring. Eliminating the need for intravenous therapy and for laboratory monitoring should allow patients to be discharged earlier, and eventually lead to the outpatient treatment of venous thromboembolism. Studies to date indicate that LMWH is safer and as effective as continuous intravenous heparin in the treatment of venous thrombosis. The decreased mortality rates seen in two clinical trials, particularly in patients with metastatic cancer, were an unexpected but intriguing finding. This requires further confirmation, in larger prospective randomized trials.