In sum, Grade I-III blunt carotid and vertebral arterial injuries (BCVI) have the potential for stroke, and should be treated. Heparin has not been shown to clearly improve healing rates compared with antiplatelet therapy. The purpose of this study is to determine whether systemic anticoagulation alters the course of Grade I-III BCVI compared with antiplatelet therapy. The investigators study hypothesis is that Grade I-III BCVI will heal or progress to pseudoaneurysm formation, independent of systemic antithrombotic regimen, and that the combination of aspirin and clopidogrel is equally efficacious in preventing neurologic symptoms compared to systemic heparin associated with Grade I-III BCVI.