 The purpose of this trial is to determine the comparative safety and efficacy of dabigatran etexilate 150 mg bid administered orally and warfarin as needed pro re nata - prn to maintain an International Normalised Ratio INR of 2.0-3.0 for 6 month treatment of acute symptomatic venous thromboembolism VTE, following initial treatment 5-10 days with a parenteral anticoagulant approved for this indication. This trial aims to demonstrate non-inferiority of dabigatran compared with warfarin in patients with acute symptomatic VTE. After achieving non-inferiority, this trial also aims to establish superiority by means of hierarchical tests of dabigatran over warfarin. 