Prophylactic vs Therapeutic Anticoagulation in Symptomatic Isolated Distal Deep Vein Thrombosis

Inclusion Criteria: * Patients aged 18-90 * Outpatients with a first, acute (within 2 weeks), symptomatic, objectively confirmed isolated distal DVT * Compliance to the scheduled follow up plan * Ability and willing to participate and sign the informed consent. Exclusion Criteria: * Any absolute contraindication to anticoagulant treatment * Pregnancy or breast-feeding * Systolic pressure \> 180 mmHg or diastolic pressure \> 100 mmHg * Platelet count \< 100 × 10⁹ /L * Serum creatinine \> 180 mmol/L or creatinine clearance ≤30 ml/min * Liver disease associated with coagulopathy and high risk of bleeding * Clinically suspected or confirmed pulmonary embolism * Ipsilateral or contralateral proximal DVT * Any indication for long-term anticoagulation * Enrolled in another clinical trial simultaneously * Life expectancy \< 6 months