A Study to Assess the Effect of YM150 for Prevention of Venous Thromboembolism in Patients Undergoing Major Abdominal Surgery

Inclusion Criteria: * Patients after a major abdominal surgery * Written informed consent obtained Exclusion Criteria: * Subject has history of symptomatic deep vein thrombosis and/or pulmonary embolism * Subject has a hemorrhagic disorder and/or coagulation disorder * Subject has had clinically important bleeding occurred within 90 days prior to the screening visit * Subject has an active bacterial endocarditis * Subject has uncontrolled severe or moderate hypertension, retinopathy, myocardial infarction or stroke * Subject is receiving anticoagulants/antiplatelet agents * Subject has a thrombocytopenia * Body weight less than 40 kg at the screening