Atherosclerotic Disease of Atherosclerotic Disease of the Carotid Artery the Carotid Artery

Atherosclerosis is a degenerative Atherosclerosis is a degenerative disease of the arteries resulting in disease of the arteries resulting in plaques consisting of necrotic cells, plaques consisting of necrotic cells, lipids, and cholesterol crystals. lipids, and cholesterol crystals.

These plaques can result in These plaques can result in symptoms by causing a stenosis, symptoms by causing a stenosis, embolizing, and thrombosing. embolizing, and thrombosing.

Atherosclerotic Disease of Atherosclerotic Disease of the Carotid Arterythe Carotid Artery

Stroke from any cause represents the Stroke from any cause represents the third leading cause of death in the third leading cause of death in the United States. United States.

Half a million new strokes occur each Half a million new strokes occur each year in the United States, resulting in year in the United States, resulting in approximately 150,000 deaths. approximately 150,000 deaths.

Stroke is the leading cause of serious Stroke is the leading cause of serious long-term disability in the United States. long-term disability in the United States. Direct and indirect cost of stroke in the Direct and indirect cost of stroke in the United States in 1997 was estimated at United States in 1997 was estimated at $40 billion. $40 billion.

Atherosclerotic Disease of Atherosclerotic Disease of the Carotid Arterythe Carotid Artery

Etiology: Etiology: Ninety percent of all Ninety percent of all extracranial carotid lesions are due to extracranial carotid lesions are due to atherosclerosis. atherosclerosis.

Pathophysiology: Pathophysiology: Currently, Currently, embolization is considered the most embolization is considered the most common mechanism causing ischemic common mechanism causing ischemic strokes from atherosclerotic lesions in strokes from atherosclerotic lesions in the carotid bulb. Thrombosis and low the carotid bulb. Thrombosis and low flow are other possible mechanisms. flow are other possible mechanisms.

Atherosclerotic Disease of Atherosclerotic Disease of the Carotid Arterythe Carotid Artery

Clinical: Clinical: Amaurosis fugax (transient visual loss) Amaurosis fugax (transient visual loss) Transient ischemic attacks (TIAs) Transient ischemic attacks (TIAs) Crescendo TIAs Crescendo TIAs Stroke-in-evolution Stroke-in-evolution Cerebral infarctionCerebral infarction

Management of Carotid Management of Carotid Artery DiseaseArtery Disease

Risk Factor Modification and Risk Factor Modification and Medical TherapyMedical Therapy

Carotid EndarterectomyCarotid Endarterectomy Carotid Artery StentingCarotid Artery Stenting

Management of Risk FactorsManagement of Risk Factors HypertensionHypertension

Hypertension is the most powerful, prevalent, Hypertension is the most powerful, prevalent, and treatable risk factor for stroke. and treatable risk factor for stroke.

Both systolic and diastolic blood pressure are Both systolic and diastolic blood pressure are independently related to stroke incidence. independently related to stroke incidence.

Reduction of elevated blood pressure Reduction of elevated blood pressure significantly lowers risk of stroke. significantly lowers risk of stroke.

Meta-analyses of randomized trials found Meta-analyses of randomized trials found that an average reduction in diastolic blood that an average reduction in diastolic blood pressure of 6 mm Hg produces a 42% pressure of 6 mm Hg produces a 42% reduction in stroke incidence. reduction in stroke incidence.

Management of Risk FactorsManagement of Risk Factors Cigarette SmokingCigarette Smoking

Cigarette smoking substantially Cigarette smoking substantially increases risk of stroke with relative increases risk of stroke with relative risk values of 1.5 to 2.2. risk values of 1.5 to 2.2.

Smoking cessation promptly reduces Smoking cessation promptly reduces risk of stroke. risk of stroke.

Management of Risk FactorsManagement of Risk FactorsBlood LipidsBlood Lipids

Recently the Scandinavian Simvastatin Recently the Scandinavian Simvastatin Survival Study (4S) reported a 30% Survival Study (4S) reported a 30% reduction in fatal and nonfatal strokes in reduction in fatal and nonfatal strokes in patients taking simvastatin.patients taking simvastatin.

Other lipid-lowering trials using statin Other lipid-lowering trials using statin drugs found a slowing of the progression drugs found a slowing of the progression of carotid atherosclerosis by ultrasound. of carotid atherosclerosis by ultrasound.

Lipid lowering may be effective in Lipid lowering may be effective in reducing risk of some kinds of reducing risk of some kinds of cerebrovascular disease. cerebrovascular disease.

Antiplatelet TherapyAntiplatelet Therapy

Antiplatelet therapy has been shown in Antiplatelet therapy has been shown in individual trials and meta-analysis to individual trials and meta-analysis to reduce risk of stroke and other vascular reduce risk of stroke and other vascular events in patients at high risk.events in patients at high risk.

The Antiplatelet Trialists Collaboration The Antiplatelet Trialists Collaboration overview found a 23% reduction in risk overview found a 23% reduction in risk for nonfatal stroke with antiplatelet for nonfatal stroke with antiplatelet therapy compared with placebo among therapy compared with placebo among persons with a history of transient persons with a history of transient ischemic attack (TIA) or stroke. ischemic attack (TIA) or stroke.

Carotid EndarterectomyCarotid Endarterectomy

CCarotid endarterectomy is an arotid endarterectomy is an excellent example of evidence-based excellent example of evidence-based medicine in practice. medicine in practice.

The beneficial effects of Carotid The beneficial effects of Carotid Endarterectomy depend on the Endarterectomy depend on the clinical presentation of the patient.clinical presentation of the patient. Symptomatic vs. AsymptomaticSymptomatic vs. Asymptomatic Degree of stenosisDegree of stenosis

Carotid Endarterectomy for Carotid Endarterectomy for Symptomatic Severe Symptomatic Severe

StenosisStenosis Randomized clinical trials have clearly Randomized clinical trials have clearly

established the benefit of carotid established the benefit of carotid endarterectomy for patients with endarterectomy for patients with symptomatic high-grade stenosis. symptomatic high-grade stenosis.

In NASCET, symptomatic patients with In NASCET, symptomatic patients with ipsilateral carotid stenosis of 70% to 99% ipsilateral carotid stenosis of 70% to 99% who were randomized to carotid who were randomized to carotid endarterectomy and medical management endarterectomy and medical management had significantly better outcomes than had significantly better outcomes than those randomized to medical management those randomized to medical management alone. alone.

Moderate stenosisModerate stenosis

In both NASCET and ECST, enrollment of In both NASCET and ECST, enrollment of symptomatic patients with moderate carotid symptomatic patients with moderate carotid artery stenosis was continued after enrollment artery stenosis was continued after enrollment of patients with severe stenosis was halted. of patients with severe stenosis was halted.

Carotid endarterectomy in symptomatic Carotid endarterectomy in symptomatic patients with carotid artery stenosis of 50% to patients with carotid artery stenosis of 50% to 69% yielded only a moderate reduction in the 69% yielded only a moderate reduction in the risk of stroke. risk of stroke.

Results of these two studies have shown that Results of these two studies have shown that carotid endarterectomy should not be carotid endarterectomy should not be performed in symptomatic patients with performed in symptomatic patients with carotid artery stenosis of less than 50%. carotid artery stenosis of less than 50%.

Asymptomatic carotid Asymptomatic carotid artery stenosisartery stenosis

It is often detected incidentally or in a It is often detected incidentally or in a patient with a neck bruit; the patient with a neck bruit; the prevalence is age-dependent and prevalence is age-dependent and ranges from 0.5% in persons under 60 ranges from 0.5% in persons under 60 years to 10% in those over 80 years.years to 10% in those over 80 years.

A number of observational studies A number of observational studies suggest that the rate of unheralded suggest that the rate of unheralded stroke ipsilateral to a hemodynamically stroke ipsilateral to a hemodynamically significant asymptomatic carotid artery significant asymptomatic carotid artery stenosis is about 1% to 2% annually stenosis is about 1% to 2% annually

Asymptomatic carotid Asymptomatic carotid artery stenosisartery stenosis

Starting in the late 1980s, a number Starting in the late 1980s, a number of clinical trials were conducted to of clinical trials were conducted to assess the benefit, if any, of carotid assess the benefit, if any, of carotid endarterectomy in reducing the risk endarterectomy in reducing the risk of ischemic stroke in asymptomatic of ischemic stroke in asymptomatic patients with carotid artery stenosis. patients with carotid artery stenosis.

Four major randomized clinical trials Four major randomized clinical trials have been performed.have been performed.

Asymptomatic carotid Asymptomatic carotid artery stenosisartery stenosis

Asymptomatic Carotid Atherosclerosis Study Asymptomatic Carotid Atherosclerosis Study (ACAS) is the largest and considered to be the (ACAS) is the largest and considered to be the most definitive study on this issue to date.most definitive study on this issue to date.

The study was terminated with a median The study was terminated with a median follow-up of 2.7 years because surgery was follow-up of 2.7 years because surgery was found to have a significant benefit. The 5-year found to have a significant benefit. The 5-year projected aggregate risk of ipsilateral stroke projected aggregate risk of ipsilateral stroke was estimated to be 11% for the medically was estimated to be 11% for the medically treated group and 5.1% for the surgically treated group and 5.1% for the surgically treated group. These risk rates translated into treated group. These risk rates translated into a 53% reduction in relative risk for ipsilateral a 53% reduction in relative risk for ipsilateral stroke in the carotid endarterectomy treatment stroke in the carotid endarterectomy treatment group group

Indications for Indications for RevascularizationRevascularization

Medical Management of Medical Management of Peripheral Vascular DiseasePeripheral Vascular Disease Most people with PAD can be treated Most people with PAD can be treated

with lifestyle changes, medications or with lifestyle changes, medications or both. Lifestyle changes to lower risk both. Lifestyle changes to lower risk include:include: Stop smoking (smokers are 2 to 25 times Stop smoking (smokers are 2 to 25 times

more likely to get PAD).more likely to get PAD). Control diabetes.Control diabetes. Control blood pressure.Control blood pressure. Be physically active (including a supervised Be physically active (including a supervised

exercise program).exercise program). Eat a low-saturated-fat, low-cholesterol diet.Eat a low-saturated-fat, low-cholesterol diet.

Medical Management of Medical Management of Peripheral Vascular DiseasePeripheral Vascular Disease PAD may require drug treatment, PAD may require drug treatment,

too. Drugs include:too. Drugs include: medicines to help improve walking medicines to help improve walking

distance (cilostazol and pentoxifylline).distance (cilostazol and pentoxifylline). antiplatelet agentsantiplatelet agents cholesterol-lowering agents (statins)cholesterol-lowering agents (statins)