A double-blind placebo-controlled randomized study on the efficacy and safety of enoxaparin for the prevention of upper limb deep vein thrombosis in cancer patients with central vein catheter

Abstract

8021 Background: Efficacy of prophylaxis with fixed dose of warfarin or low molecular weight heparin (LMWH) for upper limb deep vein thrombosis (UL-DVT) related to central vein catheter (CVC) has been claimed after open studies with limited sample size. The rate of bleeding in cancer patients receiving prolonged prophylaxis with LMWH is unclear. The aim of this study was to evaluate the efficacy and safety of the LMWH enoxaparin in the prevention of UL-DVT in cancer patients with CVC. Methods: Consecutive cancer patients with CVC for chemotherapy were included in a multicenter double-blind randomized placebo-controlled study performed in 11 Italian centers. Enoxaparin, 40 mg once a day, or placebo were given subcutaneously for 6 weeks, starting 2 hours before the CVC insertion. The primary endpoint of the study was UL-DVT, as detected by venography (CVC limb) performed at 6 weeks and/or clinically overt pulmonary embolism confirmed by objective testing. The secondary endpoints of the study were death from thromboembolic disease and death from any cause at 3-month. The safety endpoint was major bleeding. Results: 385 patients were included in the study. 321 patients underwent venography (83.4%). The primary efficacy outcome was assessed in 310 patients with adequate venography. Enoxaparin reduced the incidence of UL-DVT from 18.1 % (28/155) to 14.2 % (22/155), a relative risk reduction of 21.4 % (95% CI: 0.47 to 1.31, p=0.35). Two patients in the enoxaparin group (1.0%) and 6 patients in the placebo group (3.1%) had a symptomatic venous thromboembolism. No major bleeding occurred in both treatment groups. Minor bleeding occurred in 6.3% of the patients (12/191) in the enoxaparin group and 3.6% of the patients (7/194) in the placebo group. Conclusions: Enoxaparin, at the dose of 40 mg daily, produced a 21% non significant reduction in the incidence of CVC-related DVT in cancer patients. This dose was safe and well tolerated: this leaves open the option of increasing the dose of enoxaparin to optimize its efficacy in this clinical setting. No significant financial relationships to disclose.