Hypothesis: Aggressive screening, early angiographic diagnosis, and prompt anticoagulation for blunt carotid artery injuries (CAIs) improves neurologic outcome. Design: From January 1, 1996, through December 3 1, 2002, there were 13 280 blunt trauma admissions to our level I center, of which 643 under-went screening angiography for blunt CAI on the basis of a protocol including injury patterns and symptoms. Patients without con-traindications underwent anticoagulation immediately for documented lesions. Setting: A state-designated, level I urban trauma center Patients: Of the 643 patients undergoing screening angiography, 114 (18%) had confirmed CAI. Intervention: Early angiographic diagnosis and prompt anticoagulation. Main Outcome Measures: Diagnosis, stroke rate, and complications stratified by method of intervention. Results: A CAI was identified in 114 patients during the 7-year study period; the majority were men (71%), with a mean SD age of 34 +/- 1.3 years and a mean +/- SD Injury Severity Score of 29 +/-1.5. Seventy-three patients underwent anticoagulation after diagnosis (heparin in 54, low-molecular-weight heparin in 2, antiplatelet agents in 17); none had a stroke. Of the 41 patients who did not receive anticoagulation (because of a contraindication in 27, symptoms before diagnosis in 9, and carotid coil or stent in 5), 19 patients (46%) developed neurologic ischemia. Ischemic neurologic events occurred in 100% of patients who presented with symptoms before angio-graphic diagnosis and those receiving a carotid coil or stent without anticoagulation. Conclusions: Our prospective evaluation of blunt CAIs suggests that early diagnosis and prompt anticoagulation reduce ischemic neurologic events and their disability. The optimal anticoagulation regimen, however, remains to be established.