Extended-Duration Treatment of Superficial Vein Thrombosis of the Lower Limbs with Tinzaparin

PURPOSE: To identify risk factors for recurrent thromboembolic events (RTEs) and define the optimum duration of treatment with tinzaparin in patients with superficial vein thrombosis (SVT) of the lower limbs. MATERIALS AND METHODS: A total of 147 consecutive patients with significant SVT were treated with subcutaneously administered tinzaparin. The composite primary endpoint of the study was RTE, deep-vein thrombosis (DVT) and/or pulmonary embolism (PE) at 120 days. Patients were stratified into group A, where patients received a variable dose of tinzaparin for up to 60 days (n=98), and a subsequent group B-ext, where patients received a standardized intermediate dose of tinzaparin (n=49) for 90 days. RESULTS: RTEs occurred in 15/147 patients (10.2%), including recurrent SVT (n=10), DVT (n=4) and fatal PE (n=1). RTEs were less frequent in group B-ext (0% vs. 15.3% for group A, P=0.004), a difference that remained significant at the one-year follow-up. Clinically extensive SVT was an independent predictor for RTEs (hazard ratio, 5.94; 95% confidence interval, 2.05–17.23; P=0.001, Cox regression). Predictors or DVT or PE in group A included clinically extensive SVT (P=0.004), absence of local pain (P=0.023) and the ultrasound findings of superficial axial vein thrombosis (any, P=0.006 or isolated, P=0.036) and multiple thrombosed superficial venous sites (P<0.001). CONCLUSION: An extended three-month regimen of tinzaparin in patients with SVT of the lower limbs is more effective than a shorter course and may be desirable in patients with risk factors.