High-risk carotid surgery means that the likelihood of a complication is increased over the levels that are customarily accepted for carotid reconstruction. There are many instances where a high-risk operation should be performed, and where the increased risk is acceptable to the patient and the physician. In this presentation, I will identify the cases that I consider to be in high-risk groups and will present my evaluation and management strategy for these patients. Clearly, the surgeon considering a high-risk operation should have a good understanding of the natural history of carotid disease and the risks of surgery compared to the expected risks of medical treatment. I divide high-risk operations into several major categories. These include predictably difficult operations, cases with high risk for medical complications, cases with high risk for intraoperative ischemia, and cases with high risk for postoperative occlusion/stroke. Predictably, difficult operations include those with peculiar anatomical variants, reoperation, irradiated carotids, or extreme high exposures. With special emphasis on technique, these cases can be well performed surgically and the presentation will illustrate such cases. Patients with high-risk for medical complications include those with recent myocardial infarction, unstable angina, diabetic patients, patients with severe pulmonary disease, and patients who require continued postoperative anticoagulation (usually for heart valves). In many cases, these patients can undergo successful surgery; some such cases may also be suitable for endovascular treatment, particularly for recent myocardial disease. Patients with high-risk for intraoperative ischemia require that the surgeon have a solid knowledge of shunt placement and other strategies for cerebral protection. These include patients with contralateral occlusion, difficult shunt placements, high or difficult exposures, unstable neurological deficits, and propagating intraluminal thrombus high up the internal carotid. Patients with high risk for postoperative occlusion or stroke include diabetic patients, high focal lesions in the ICA, patients with postoperative hypotension, and hypertensive patients with headache following opening of a tight stenosis (dysautoregulated brain). In the majority of these cases, the use of a Hemashield patch graft will reduce or eliminate the chances of postoperative problems. Carotid surgery can be well performed by an experienced surgeon even in high-risk groups, and at present it remains the best-proven treatment for these cases. In the future, endovascular treatments may become common for some of these cases, but the scientific evidence to support this must still be proven. The most important factors in assuring a successful operation are careful planning, experience, and a high skill level for the operating surgeon. (C) 2002 Published by Elsevier Science B.V.