Reduction in thrombus extension and clinical end points in patients after initial treatment for deep vein thrombosis with the fixed-dose body weight-independent low molecular weight heparin certoparin

Low molecular weight heparin (LMWH) is effective in the treatment of acute deep vein thrombosis (DVT) in adults. This has not been demonstrated for on e LMWH alone. The relationship between venographic changes due to LMWH ther apy and clinical outcome in the initial treatment period has not been repor ted. A pooled analysis of two clinical trials was performed. The trials com pared a fixed-dose, body weight-independent, subcutaneous LMWH, certoparin (8000 antifactor Xa [aXa] U twice a day [b.i.d.]), with an adjusted-dose in travenous unfractionated heparin (UFH) with respect to venographic changes expressed as Marder score and occurrence of recurrent venous thromboembolis m, major bleeding, and mortality. The Marder score was 23.2 +/- 8.4 in pati ents randomized to LMWH (n = 299 paired phlebograms) and 23.9 +/- 8.9 in pa tients allocated to UFH (n = 297 paired phlebograms) at entry (2p = 0.23) a nd 18.9 +/- 9.7 and 20.5 +/- 9.9 at the end of the initial therapy (2p = 0. 04), respectively. The composite outcome of recurrent venous thromboembolis m, major bleeding, and mortality occurred less frequently during treatment with LMWH (n = 393) than it did with UFH (n = 404,1.3% versus 5.0%, risk re duction [RR] 0.26, 95% confidence interval [CI] 0.11 to 0.63, 2p = 0.004). Single events of recurrent thromboembolism (2p = 0.12), major bleeding (2p = 0.03), and mortality (2p = 0.12) were observed less frequently with LMWH. A trend toward a lack of regression of thrombus size was observed in recur rent venous thromboembolism (2p = 0.08). Body weight-independent LMWH signi ficantly reduces thrombus size and the incidence of composite outcome durin g the initial treatment of acute proximal venous thrombosis compared with a djusted dose, intravenous UFH. The data indicate a relation between an unim proved Marder score and a recurrent venous thromboembolism.