An international multicentre study: Clivarin in the prevention of venous thromboembolism in patients undergoing general surgery. Report of the International Clivarin Assessment Group

Abstract

A randomized multicentre double-blind study was organized to evaluate the efficacy and the safety of Clivarin (reviparin-sodium) (anti-Xa/anti-IIa ratio: 3-5 International units) for the prevention of post-operative thromboembolism in patients undergoing general surgery. 1,351 patients were randomly allocated to receive subcutaneously either 5,000 U of unfractionated heparin (UFH) twice a day or 1,750 anti-Xa IU of reviparin-sodium once a day (morning) followed by a placebo injection (evening) for at least 6 days. Deep vein thrombosis (DVT) was detected with the 125I-fibrinogen technique confirmed by phlebography if necessary. After randomization thrombotic risk factors were equally distributed in each group. More than 50% of the patients had a cancer. The incidence of DVT and of pulmonary embolism was 4.8% (CI 95%: 3.3-6.7%) in the reviparin-sodium group and 4.4% (CI 95%: 2.9-6.2%) in the UFH group, a non-significant difference. The number of transfusions required was equivalent in the two groups. However, post-operative bleeding complications, including wound haematomas and internal bleeding, were less frequent in the reviparin-sodium group (P < 0.01). Therefore, for the first time, this study demonstrates that an unusual low dose of a low molecular weight heparin retains its antithrombotic efficacy by comparison with UFH and that the tolerance of this low dose is better.