The efficacy and safety of antithrombotic treatment in patients with superficial vein thrombosis remain to be established in adequately designed trials.
In a double-blind trial, 427 patients older than 18 years, with documented acute symptomatic superficial vein thrombosis of the legs, were randomly assigned to receive subcutaneous enoxaparin sodium, 40 mg; subcutaneous enoxaparin, 1.5 mg/kg; oral tenoxicam; or placebo, once daily for 8 to 12 days. The primary efficacy outcome was deep venous thromboembolism between days 1 and 12, defined as deep vein thrombosis detected by ultrasonography between days 8 and 12 or earlier if clinically indicated, or documented symptomatic pulmonary embolism. For the secondary efficacy outcomes, superficial vein thrombosis recurrence or extension was also considered.
The incidence of deep venous thromboembolism by day 12 was 3.6% (4 of 111 patients) in the placebo group, 0.9% (1 of 109 patients) in the 40-mg enoxaparin group (P = .37 vs placebo), 1.0% (1 of 102 patients) in the 1.5-mg/kg enoxaparin group (P = .37 vs placebo), and 2.1% (2 of 94 patients) in the tenoxicam group (P = .69 vs placebo). The incidence of deep and superficial venous thromboembolism by day 12 was significantly reduced in all active treatment groups, from 30.6% (34 of 111 patients) in the placebo group to 8.3% (9 of 109 patients), 6.9% (7 of 102 patients), and 14.9% (14 of 94 patients) in the 40-mg enoxaparin (P<.001), 1.5-mg/kg enoxaparin (P<.001), and tenoxicam (P<.01) groups, respectively. No death or major hemorrhage occurred during the study.
Treatment with a low-molecular-weight heparin or with an oral nonsteroidal anti-inflammatory agent should be evaluated further in the prevention of thromboembolic complications in patients with superficial vein thrombosis.