The diagnosis and treatment of asymptomatic and symptomatic patients with carotid artery stenosis

Carotid artery atherosclerotic stenosis is an important annual cause of stroke in the United States. Moreover, the incidence of carotid artery stenosis is significantly increasing due to the widespread popularity of high fat and high salt diets, sedentary lifestyles, and the increasing age of the population. Of major importance to cardiovascular specialists is the fact that individuals with atherosclerotic carotid artery stenosis can have a prevalence of atherosclerotic coronary artery disease as high as 50 to 75%. Vascular screening for carotid artery stenosis with Doppler ultrasound should be considered for all symptomatic patients with possible carotid stenosis and also considered for asymptomatic patients with (1) symptomatic peripheral arterial disease, coronary artery disease, or atherosclerotic aortic aneurysm or, (2) multiple atherosclerotic risk factors. Carotid artery atherosclerotic plaques that are at high risk for rupture and thrombosis or cerebral embolization are characterized by large lipid cores, intraplaque hemorrhage, thin fibrous caps less than 165 mu ms that are infiltrated by macrophages and T cells or have surface ulcer(s) or fissures. Carotid artery plaque rupture with cerebral embolism can cause a stroke, transient ischemic attacks (TIA), or ipsilateral blindness (amaurosis fugax). Medical treatment based on the recommendations of the American and European Societies for Vascular Surgery and the American Heart Association for symptomatic patients with carotid stenosis and also asymptomatic patients with high risk carotid stenosis plaques include antiplatelet drugs, antihypertensive drugs for hypertension control and lipid lowering drugs. Management strategies and decisions about carotid revascularization in asymptomatic patients with high risk carotid stenosis should involve a multidisciplinary team and shared decision-making is recommended. The 30 day and five to 10 year outcomes in asymptomatic carotid stenosis patients who have undergone carotid endarterectomy, carotid stenting and/or optimal medical therapy are summarized from the Veterans Administration Cooperative Study, the Asymptomatic Carotid Atherosclerosis Study and the Asymptomatic Carotid Surgery Trials. The current Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial (CREST-2) should help to resolve the debate regarding carotid artery revascularization versus primary medical treatment in asymptomatic patients with >70% carotid artery stenosis. Symptomatic patients who present within 4.5 hours of stroke onset require evaluation for acute intravenous pharmacologic thrombolysis and patients who present with large vessel occlusion within 24 hours of symptom onset should be considered for mechanical thrombectomy to reduce the neurologic deficit. Patients with carotid artery stenosis who present with a history of cerebral infarct in the preceding six months due to cerebral embolism require medical treatment and evaluation by a multidisciplinary team for carotid revascularization in order to prevent future strokes or TIAs. The outcomes of the North American Symptomatic Carotid Endarterectomy Trial, Carotid Revascularization Endarterectomy Versus Stent Trial, Stent-Supported Percutaneous Angioplasty of the Carotid Artery vs. Endarterectomy Trial, and the Safety and Efficacy Study for Reverse Flow Used during Carotid Artery Stenting Procedure trials for symptomatic patients with carotid stenosis are reviewed. A synopsis of treatment guidelines for symptomatic and asymptomatic carotid stenosis patients from the American and European Societies of Vascular Surgery and the American Heart Association/American Stroke Association are presented. Each patient with carotid artery stenosis must be carefully evaluated to determine the best treatment based on the clinical presentation, the imaging and laboratory diagnostic information, the treatment guidelines, and the patient needs and preferences as well as the patient's social and cultural factors.