Carotid angioplasty and stenting (CAS) with embolic protection is currently accepted as treatment for patients considered to be at high risk for carotid endarterectomy (CEA). The purpose of this study was (1) to determine what proportion of patients treated with CEA would be categorized as "high" risk by currently accepted criteria, (2) to characterize preoperative angiographic findings in patients with carotid stenosis, and (3) to determine the potential technical challenges of CAS in these patients. Consecutive patients who underwent CEA from January 1999 through August 2004 prior to introduction of CAS at our institution were identified. Demographics, indications, perioperative complications, and deaths were reviewed. Published guidelines defining high risk for CEA were applied, and preoperative angiograms were examined for technical limitations to CAS. Two hundred and seventy-nine CEAs were performed in 259 patients for asymptomatic carotid occlusive disease (57%), transient ischemic attacks (35%), or stroke (8%) during the study period. Of these, 35.5% (n = 99) would have met one or more high-risk criteria. Overall risks of perioperative stroke, myocardial infarction, and death were 1.1%, 2.2%, and 0.4% (n = 279), respectively, with a combined major complication rate of 3.3%. No difference in major complication rates was observed between standard-risk and high-risk patients. Preoperative angiograms were available for review in 83.5% of CEAs (n = 233). The distribution of aortic arch configurations included types I (3.5%), IIa (39.5%), IIb (54.5%), and III (1.3%). Aortic arch anomalies were observed in 15.5% (n = 35) of angiograms. There were 77.7% (n = 181) with one or more angiographic findings that would have increased the technical difficulty of CAS, but only 17.6% had relative angiographic contraindications to CAS. A significant proportion of patients with carotid stenosis previously managed with CEA would be categorized as high risk and considered potential candidates for CAS by currently accepted criteria. Based on preoperative angiography, technically challenging factors, some of which limit the ability to perform CAS, are common and should be anticipated when planning CAS. © 2008 Annals of Vascular Surgery Inc.