Risk factors for recurrent events in subjects with superficial vein thrombosis in the randomized clinical trial SteFlux (Superficial Thromboembolism Fluxum)

Abstract

Background/aims: To evaluate risk factors for recurrent events in patients enrolled in the SteFlux (Superficial Thromboembolism Fluxum) clinical trial which compared different doses and duration of low molecular weight heparin (parnaparin) for superficial vein thrombosis (SVT).

Materials and methods: Outpatients with acute SVT of at least 4 cm in length of the internal or external saphenous veins or their collaterals were randomized in a double blind fashion to receive either parnaparin 8500 UI aXa od for ten days followed by placebo for 20 days or 8500 UI aXa od for ten days followed by 6400 UI aXa od for 20 days or 4250 UI aXa od for 30 days. Outcomes were the composite of symptomatic and asymptomatic deep vein thrombosis, pulmonary embolism and SVT recurrence or extension in the first 30+/-3 days with a 60+/-3 day follow-up.

Results: 98 outcomes (14.7%) were recorded during 93 days among 664 patients (M/F: 246/418, mean age 65). After correction for treatment, outcomes during 33 days were associated with previous venous thromboembolism (VTE) and/or SVT and/or family history of VTE (odds ratio-OR: 2.5; 95% confidence interval - CI: 1.4-4.8; p=0.003). After stopping LMWH treatment, only the absence of varicose veins (OR: 2.5; 95% CI 1.3-5.0; p=0.004) and previous VTE and/or SVT and/or family history of VTE (OR: 1.9; 95% CI:1.0-3.7; p=0.048) were significantly associated with outcomes.

Conclusions: SVT patients with these factors may deserve a higher intensity and/or longer anticoagulant treatment.

Keywords: Deep vein thrombosis; Low molecular weight heparin; Pulmonary embolism; Randomized clinical trial; Superficial vein thrombosis; Venous thromboembolism.