Different Doses and Duration of Low Molecular Weight Heparin (Parnaparin)in Superficial Vein Thrombosis

Inclusion Criteria: * Weight \> 50 kg and less than 110 kg * SVT of the grand saphenous vein for at least 4 cm * SVT of the small saphenous vein for at least 4 cm * Collateral SVT of the large saphenous vein of the thigh for at least 4cm Exclusion Criteria: * SVT of the grand saphenous vein reaching the saphenofemoral cross (within 3 cm) * SVT of the small saphenous vein reaching the saphenopopliteal cross * Documented proximal or distal DVT or pulmonary embolism * SVT secondary to sclerotherapy * Pregnancy and puerperium * uncontrolled arterial hypertension (Systolic pressure \> 180 mmHg and diastolic pressure \> 110 mmHg) * Active peptic ulcer * Bacterial endocarditis * Stroke in the previous 3 months * Haemorrhagic diathesis * Thrombocytopenia (platelets \< 100,000/ µL) * Hypersensitivity to heparin or history of thrombocytopenia induced by heparin * Creatinine \> 2 mg% (\> 180 µmol/L) * Heparin therapy (any dose) or anticoagulant therapy for longer than the previous 72 hours * In-hospital development of SVT * Previous saphenectomy by any method * Surgery in the previous 30 days * Serious liver disease * Use of dextran, mannitol, thrombolytic treatment, chronic use of NSAID and cortisone-based drugs. * Active cancer or under chemotherapy or radiotherapy * Thrombectomy of superficial vein involved * Refusal to give informed consent