<qa>  What is the purpose of this trial?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. 