Effect of low molecular weight heparin versus warfarin sodium on mortality in long-term treatment of proximal vein thrombosis

Several different low molecular weight (LMW) heparins. when given by a once- or twice-daily subcutaneous injection without laboratory monitoring, have been shown to be as effective or more effective than continuous intravenous, unfractionated heparin monitored by the activated partial thromboplastin time. One such study demonstrated a statistically significant decrease in mortality rate over the 3-month follow-up of the study. This was particularly striking in patients with cancer. Based on these findings, a multicenter, randomized clinical trial has been designed to test the effect of long-term, once-daily LMW heparin with standard treatment with heparin and warfarin on the mortality rate in patients with proximal deep vein thrombosis. The study is stratified to ensure that equal numbers of cancer patients are in both arms. This will demonstrate whether or not the long-term use of LMW heparin can have a significant impact on mortality in patients with proximal venous thrombosis with or without the presence of cancer.