Screening and preoperative imaging of candidates for carotid endarterectomy.

Randomized clinical trials have provided us with clinical guidelines regarding the indications for performing carotid endarterectomy in patients who have symptomatic and asymptomatic disease. Logically, any patient with a history of transient ischemic attacks, amaurosis fugax, or stroke should be evaluated for extracranial carotid artery occlusive disease. In asymptomatic patients, however, carotid artery surveillance may be helpful in identifying those at risk before neurological events. Patients at particularly high risk include those identified with (1) manifestations of systemic atherosclerotic disease (peripheral vascular disease, coronary artery disease, renovascular disease); (2) presence of a carotid bruit; (3) advanced age (> 65 years); and (4) ABI less than 0.7. Duplex ultrasonography remains the best and most widely used noninvasive screening method, but its accuracy is highly technologist dependent. A high-quality duplex study may, in itself, be adequate to determine whether the severity of extracranial carotid occlusive disease warrants surgical intervention. Catheter-based arteriography may be used as an adjunct to validate duplex results, but its invasive nature and risk of complications has popularized alternative imaging methods. Of these, magnetic resonance angiography (MRA) and spiral computed tomographic angiography (CTA) show excellent promise as noninvasive imaging techniques for the evaluation of extracranial carotid artery occlusive disease.