Guide to Anticoagulant Therapy: Heparin : A Statement for Healthcare Professionals From the American Heart Association

Although deep-vein thrombosis and pulmonary embolism are considered common complications after major trauma, their frequency and the associated risk factors have not been carefully quantified. We performed serial impedance plethysmography and lower-extremity contrast venography to detect deep-vein thrombosis in a cohort of 716 patients admitted to a regional trauma unit. Prophylaxis against thromboembolism was not used. Deep-vein thrombosis in the lower extremities was found in 201 of the 349 patients (58 percent) with adequate venographic studies, and proximal-vein thrombosis was found in 63 (18 percent). Three patients died of massive pulmonary embolism before venography could be performed. Before venography, only three of the patients with deep-vein thrombosis had clinical features suggestive of the condition. Deep-vein thrombosis was found in 65 of the 129 patients with major injuries involving the face, chest, or abdomen (50 percent); in 49 of the 91 patients with major head injuries (53.8 percent); in 41 of the 66 with spinal injuries (62 percent); and in 126 of the 182 with lower-extremity orthopedic injuries (69 percent). Thrombi were detected in 61 of the 100 patients with pelvic fractures (61 percent), in 59 of the 74 with femoral fractures (80 percent), and in 66 of the 86 with tibial fractures (77 percent). A multivariate analysis identified five independent risk factors for deep-vein thrombosis: older age (odds ratio, 1.05 per year of age; 95 percent confidence interval, 1.03 to 1.06), blood transfusion (odds ratio, 1.74; 95 percent confidence interval, 1.03 to 2.93), surgery (odds ratio, 2.30; 95 percent confidence interval, 1.08 to 4.89), fracture of the femur or tibia (odds ratio, 4.82; 95 percent confidence interval, 2.79 to 8.33), and spinal cord injury (odds ratio, 8.59; 95 percent confidence interval, 2.92 to 25.28). Venous thromboembolism is a common complication in patients with major trauma, and effective, safe prophylactic regimens are needed.

Platelets are believed to play a part in the ischemic complications of coronary angioplasty, such as abrupt closure of the coronary vessel during or soon after the procedure. Accordingly, we evaluated the effect of a chimeric monoclonal-antibody Fab fragment (c7E3 Fab) directed against the platelet glycoprotein IIb/IIIa receptor, in patients undergoing angioplasty who were at high risk for ischemic complications. This receptor is the final common pathway for platelet aggregation. In a prospective, randomized, double-blind trial, 2099 patients treated at 56 centers received a bolus and an infusion of placebo, a bolus of c7E3 Fab and an infusion of placebo, or a bolus and an infusion of c7E3 Fab. They were scheduled to undergo coronary angioplasty or atherectomy in high-risk clinical situations involving severe unstable angina, evolving acute myocardial infarction, or high-risk coronary morphologic characteristics. The primary study end point consisted of any of the following: death, nonfatal myocardial infarction, unplanned surgical revascularization, unplanned repeat percutaneous procedure, unplanned implantation of a coronary stent, or insertion of an intraaortic balloon pump for refractory ischemia. The numbers of end-point events were tabulated for 30 days after randomization. As compared with placebo, the c7E3 Fab bolus and infusion resulted in a 35 percent reduction in the rate of the primary end point (12.8 vs. 8.3 percent, P = 0.008), whereas a 10 percent reduction was observed with the c7E3 Fab bolus alone (12.8 vs. 11.5 percent, P = 0.43). The reduction in the number of events with the c7E3 Fab bolus and infusion was consistent across the end points of unplanned revascularization procedures and nonfatal myocardial infarction. Bleeding episodes and transfusions were more frequent in the group given the c7E3 Fab bolus and infusion than in the other two groups. Ischemic complications of coronary angioplasty and atherectomy were reduced with a monoclonal antibody directed against the platelet IIb/IIIa glycoprotein receptor, although the risk of bleeding was increased.