Deep vein thrombosis of the legs: new therapy by means of low molecular weight heparins.

This open controlled study compared the effects of subcutaneous administration of two types of heparin in two groups of 40 patients each with deep vein thrombosis. One group received calcium heparin and the other received low molecular weight heparin for 40 days in each case. Patients receiving low molecular weight heparin showed a greater increase in inhibition of activated factor X than those receiving calcium heparin. Both drugs slightly reduced activated partial thromboplastin time. No patient experienced pulmonary embolism during the study. At the end of the study, maximum venous outflow was significantly higher in patients given low molecular weight heparin than in those given calcium heparin. No major side-effects were observed. This study showed that: (a) the anti-thrombotic effect of low molecular weight heparin was greater than for calcium heparin; and (b) low molecular weight heparin improved maximum venous outflow in approximately half of the patients, possibly by promoting or accelerating recanalization of the vessel.