A randomized double-blind study of low-molecular-weight heparin (parnaparin) for superficial vein thrombosis: STEFLUX (Superficial ThromboEmbolism and Fluxum).

BACKGROUND: Optimal doses and duration of low-molecular-weight heparin (LMWH) for the treatment of superficial vein thrombosis (SVT) are still uncertain.

OBJECTIVES: To compare the efficacy and safety of different doses and durations of LMWH parnaparin for symptomatic lower limb SVT.

PATIENTS AND METHODS: Outpatients with at least a 4-cm-long SVT of long or short saphenous veins or their collaterals were randomized to receive parnaparin either 8500 UI once daily ( o.d.) for 10 days followed by placebo for 20 days (group A) or 8500 UI o.d. for 10 days followed by 6400 UI once daily (o.d.) for 20 days (group B) or 4250 UI o.d. for 30 days (group C) in a double-blind fashion in 16 clinics. Primary outcome was the composite of symptomatic and asymptomatic deep vein thrombosis (DVT), symptomatic pulmonary embolism (PE) and relapse and/or symptomatic or asymptomatic SVT recurrence in the first 33 days with 60 days follow-up.

RESULTS: Among 664 patients, primary outcome occurred in 33/212 (15.6%), 4/219 (1.8%) and 16/217 (7.3%) subjects in groups A, B and C, respectively (B vs. A: absolute risk reduction [ARR]: 13.7%, 95% confidence intervals [CI]: 8-18.9 P<0.001; B vs. C: ARR: 5.5%; 95% CI: 1.6-9.4 P= 0.011; C vs. A: ARR: 8.2%, 95% CI: 2-14 P=0.012). During days 0-93, the event rate was higher in group A (22.6%) than either in group B (8.7%; P=0.001) or C (14.3%, P=0.034). No major hemorrhages occurred.

CONCLUSIONS: An intermediate dose of parnaparin for 30 days is superior to either a 30-day prophylactic dose or a 10-day intermediate dose for lower limb SVT treatment.