Sulodexide, VESSEL®, for the Prevention of Recurrent Venous Thromboembolism (The Jason Study)

Inclusion Criteria: 1. Patients with a first event of proximal lower extremity DVT and / or PE, idiopathic or associated with weak or removed risk factors. 2. Patients aged ≥75 years at the time of enrolment 3. Patients with at least one of the known risk factors of bleeding (APPENDIX 1): 1. Hypertension 2. Renal failure 3. Thrombocytopenia 4. Diabetes 5. Antiplatelet therapy (ASA maximum 140 mg/die) 6. Frequent falls (\>2 /years) 7. Nonsteroidal anti-inflammatory drug 8. Liver failure 9. Previous Stroke 10. Anemia 11. Poor anticoagulant control 12. Alcohol abuse 4. Patients of both sexes. 5. Patients who at the time of enrolment have already undergone a period of anticoagulant therapy (AT, with any medication) of at least 3 months and the therapy has not been suspended for more than 30 days. 6. Patients with no other AT indications. 7. Patients capable and able to provide informed consent Exclusion Criteria: 1. Patients aged \<75 years at the time of the recruitment visit. 2. "Provoked" index event, which occurred: * Within 3 months of surgery or major trauma, * Bed Rest \> 4 days, * Cast / immobility within 3 months. 3. Index event represented by severe PE, with life threatening risk or treated with thrombolytic therapy. 4. Index event represented by isolated distal DVT or superficial venous thrombosis. 5. Thrombotic event in sites other than the deep proximal veins of the lower limbs. 6. Anticoagulant therapy for less than 3 months at the time of enrolment. 7. Discontinuation of anticoagulant therapy for over thirty days at the time of enrolment 8. Recurrent episodes of DVT ± PE