Prevention of venous thromboembolism in patients undergoing minimally invasive surgery with a short-term hospital stay - Results of a multicentric, prospective, randomised, controlled clinical trial with a low-molecular-weight heparin

A prospective, randomised, controlled clinical trial was carried out in order to elucidate the incidence of venous thromboembolism in selected patients undergoing laparoscopic cholecystectomy and other types of minimally invasive surgery, as well as to show safety and efficacy of a low-molecular-weight heparin (LMWH) in the prevention of post-operative venous thromboembolism. Seven hundred and eighteen patients were randomly allocated to one of two groups: One group received physical measures for prevention of deep-vein thrombosis, i.e. graduated elastic stockings (n = 359). The second group also received graduated elastic stockings and, additionally, a LMWH (reviparin sodium, Clivarin) SC once daily (n = 359). For safety reasons, with respect to the untreated control group, patients with three or more risk factors for venous thromboembolism were not included into the trial. Diagnosis for DVT was systematically done by duplex scan. In this, rather artificial low-risk selection the overall incidence of thromboembolic events was surprisingly low: five cases of suspected pulmonary embolism, confirmed by scintigraphy in one case only, and one patient with phlebographically confirmed calf vein thrombosis. The use of reviparin for prevention of venous thromboembolism was safe and convenient - the rate of post-operative bleeding complications was 2.3 % in the LMWH group, even lower than in the control group (3.2 %). The real incidence of venous thromboembolism in patients undergoing laparoscopic cholecystectomy remains unclear. Further trials with unselected patients are needed.