A Study to Evaluate the Efficacy and Safety of Fondaparinux Sodium When Used With Intermittent Pneumatic Compression to Prevent Venous Thromboembolic (IPC) Versus IPC Alone for the Prevention of Venous Thromboembolic Events in Subjects at Increased Risk Undergoing Major Abdominal Surgery (APOLLO).

Inclusion Criteria: * Undergoing abdominal surgery (any surgery between the diaphragm and pelvic floor) lasting longer than 45 minutes (duration from anesthesia induction to surgical closure) * Over 40 years of age * Subject who had signed the informed consent. Exclusion Criteria: * Active, clinically significant bleeding * Documented congenital or acquired bleeding tendency/disorders * Active ulcerative gastrointestinal disease unless the reason for the present surgery. * Recent intracranial hemorrhage or recent (less than 3 months prior to randomisation) brain, spinal, or ophthalmologic surgery. * Indwelling intrathecal or epidural catheters for more than 6 hours after surgical closure. * Subjects who had a traumatic puncture or unusual difficulty in applying the catheter * Known cerebral metastasis, * Subjects in whom hemostasis had not been established 6 hours after surgical closure, * Current thrombocytopenia, * Bacterial endocarditis * Creatinine level above 2.0 mg/dL (180 μmol/L) in a well-hydrated subject, * Documented hypersensitivity to contrast media, * Use of any contraindicated drug that could not be combined with the injection of contrast medium, * Patent with evidence of leg ischemia caused by peripheral vascular disease, unable to undergo IPC and unable to wear Elastic Stockings. Exclusion criteria related to trial methodology: * Mental disorders that could interfere with study participation and/or failure to give written informed consent to take part in the study, * Subject's life expectancy \< 6 months, * Clinical sign of DVT and/or history of recent DVT, * Participation in any other therapeutic drug study or a device study evaluating DVT prophylaxis within 90 days preceding inclusion, * Previous participation in a study of fondaparinux sodium, * Known hypersensitivity to fondaparinux and its excipients, * Current addictive disorders that could interfere with study participation, * Administration of heparin, heparinoids, LMWH, oral anticoagulants, dextrans, hirudin, fibrinolytic agents or drugs blocking glycoprotein platelet receptors (GPIIb-IIIa) during the screening period, i.e., from admission to surgery, * Subjects for whom anticoagulant therapy was contraindicated or who had, due to concomitant disease, an indication for oral anticoagulant or heparins (including LMWH) and who could not discontinue those treatments, * Women of child-bearing potential: women not using an appropriate contraceptive method during the whole duration of study participation , * Subject with body weight \<50 kg, * Subjects, who in the opinion of the investigator, required a pharmacological prophylaxis in addition to intermittent pneumatic compression, * Known pregnancy and / or women who intended to breastfeed, * Subjects undergoing vascular surgery such as aorto-femoral bypass graft