PROLONGED THROMBOPROPHYLAXIS FOLLOWING HIP-REPLACEMENT SURGERY - RESULTS OF A DOUBLE-BLIND, PROSPECTIVE, RANDOMIZED, PLACEBO-CONTROLLED STUDY WITH DALTEPARIN (FRAGMIN(R))

Discontinuation of thromboprophylaxis a few days after surgery may unm ask delayed hypercoagulability and contribute to late formation of dee p venous thrombosis (DVT). To investigate whether thromboprophylaxis s hould be prolonged beyond the hospital stay, a prospective, double-bli nd randomised study was conducted in 308 patients. All patients receiv ed initial thromboprophylaxis with dalteparin, dextran and graded elas tic stockings. On day 7, patients were randomised to receive daltepari n (Fragmin(R)) 5000 IU once daily, or placebo, for 4 weeks. Ail patien ts were subjected to bilateral venography, perfusion ventilation scint igraphy and chest X-ray on days 7 and 35. Patients with venographicall y verified proximal DVT on day 7 were withdrawn from the randomised st udy to receive anticoagulant treatment. The overall prevalence of DVT on day 7 was 15.9%. On day 35, the prevalence of DVT was 31.7% in plac ebo-treated patients compared with 19.3% in dalteparin-treated patient s (p = 0.034), The incidence of DVT from day 7 to day 35 was 25.8% in the placebo-treated group versus 11.8% in the dalteparin-treated group (p = 0.017). The incidence of symptomatic pulmonary embolism (PE) fro m day 7 to day 35 was 2.8% in the placebo-treated group compared with zero in the dalteparin-treated group. This included one patient who di ed from PE. No patients experienced serious complications related to t he injections of dalteparin or placebo. This study shows that prolonge d thromboprophylaxis with dalteparin, 5000 IU, once daily for 35 days significantly reduces the frequency of DVT and should be recommended f or 5 weeks after hip replacement surgery.