 Increased VTE risk is defined as a cumulative VTE risk score 4, so that patients with at least 1 major risk factor cancer, prior VTE, or hypercoagulability plus at least 1 additional intermediate risk factor major surgery or bed rest or minor risk factor advanced age, obesity, or hormone replacement therapyoral contraceptives become eligible. In the absence of a major risk factor, patients with 1 intermediate risk factor plus at least 2 minor risk factors become eligible. 