Subcutaneous low molecular weight heparin compared with continuous intravenous unfractionated heparin in the treatment of proximal deep vein thrombosis: a systematic review

It is difficult to draw conclusions from published meta-analysis on the tre atment of proximal deep vein thrombosis by low molecular weight heparins in view of methodological problems related to selection of the studies and th e addition of early and late complications. To determine the efficacy and s afety of subcutaneous low molecular weight heparins in the initial treatmen t of proximal deep vein thrombosis we reviewed all published randomised con trolled studies comparing this treatment to the standard intravenous unfrac tionated heparin regimen. Adverse events were taken into account up to 48 h ours after cessation of heparin treatment. Results point towards equivalent or greater efficacy, with reduction in thr ombosis size, and safety of low molecular weight heparin. The mortality rat e was low (0-1.2%). Incidence of recurrent venous thromboembolism (0-2%) or major bleeding (0-2.4%) was also low, though such events were linked to a high mortality rate (9-16%). Thrombocytopenia occurred in 0 to 2.5% of case s.