Carotid Endarterectomy: When and in Whom?

Carotid endarterectomy has been a widely used method of preventing primary or secondary cerebrovascular ischemic events since the 1950s. Over the past several years, the interest in this surgical procedure has increased due to the publication of several large randomized trials comparing best medical therapy (antithrombotic) with carotid endarterectomy. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) has demonstrated a risk reduction of 65% in patients who underwent carotid endarterectomy for symptomatic carotid stenosis. The Asymptomatic Carotid Atherosclerosis Study (ACAS) also demonstrated a benefit of carotid endarterectomy, however, in a group of asymptomatic patients. There was an approximate reduction of 6% in stroke in patients undergoing carotid endarterectomy in this series. Carotid endarterectomy is the treatment of choice in patients with symptomatic extracranial carotid atherosclerosis. Data is now emerging that this is also an effective therapy in patients with asymptomatic carotid stenosis. The perioperative stroke risk by the surgeon performing the procedure and the patient's co-morbid medical conditions are important factors to consider before proceeding with surgical treatment of this disorder.     

Comparative Review of the Treatment Methodologies of Carotid Stenosis

The treatment of carotid stenosis entails three methodologies, namely, medical management, carotid angioplasty and stenting (CAS), as well as carotid endarterectomy (CEA). The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) have shown that symptomatic carotid stenosis greater than 70% is best treated with CEA. In asymptomatic patients with carotid stenosis greater than 60%, CEA was more beneficial than treatment with aspirin alone according to the Asymptomatic Carotid Atherosclerosis (ACAS) and Asymptomatic Carotid Stenosis Trial (ACST) trials. When CAS is compared with CEA, the CREST resulted in similar rates of ipsilateral stroke and death rates regardless of symptoms. However, CAS not only increased adverse effects in women, it also amplified stroke rates and death in elderly patients compared with CEA. CAS can maximize its utility in treating focal restenosis after CEA and patients with overwhelming cardiac risk or prior neck irradiation. When performing CEA, using a patch was equated to a more durable result than primary closure, whereas eversion technique is a new methodology deserving a spotlight. Comparing the three major treatment strategies of carotid stenosis has intrinsic drawbacks, as most trials are outdated and they vary in their premises, definitions, and study designs. With the newly codified best medical management including antiplatelet therapies with aspirin and clopidogrel, statin, antihypertensive agents, strict diabetes control, smoking cessation, and life style change, the current trials may demonstrate that asymptomatic carotid stenosis is best treated with best medical therapy. The ongoing trials will illuminate and reshape the treatment paradigm for symptomatic and asymptomatic carotid stenosis.     

Surgery Insight: carotid endarterectomy--which patients to treat and when?

Over the past 15 years, we have witnessed a resurgence of surgery for prevention of ischemic stroke. Landmark trials including the North American Symptomatic Carotid Endarterectomy Trial and the European Carotid Surgery Trial have explored the role of carotid endarterectomy in this context, comparing the procedure with best medical treatment in patients with high-grade stenosis of the internal carotid artery and transient ischemic attack or minor nondisabling stroke in the same territory. Here, we discuss the lessons learnt from these trials, and review the Asymptomatic Carotid Atherosclerosis Study and the Asymptomatic Carotid Surgery Trial, which attempted to resolve the rather vexing issue of surgical treatment for patients with asymptomatic internal carotid artery stenosis. We also review the best medical treatment for patients undergoing carotid endarterectomy in the perioperative period, and examine the risk of ischemic stroke after CABG surgery, both when this procedure is performed alongside endarterectomy and when CABG surgery and endarterectomy are performed as a two-staged procedure.     

Surgical and percutaneous management of carotid artery stenosis

Stroke is one of the leading causes of morbidity and mortality in the United States. Approximately 700,000 Americans suffer from a stroke per year and 270,000 of these patients will die as a result of their stroke. The etiology of cerebrovascular events can be attributed to carotid artery disease in 20-30% of cases. Carotid endarterectomy has been shown to be beneficial in selected patients with symptomatic and asymptomatic carotid artery stenosis. Percutaneous treatment of carotid disease appears to be effective when performed with distal protection by an experienced operator. This review presents the clinical trial data regarding surgical and percutaneous management of carotid disease.     

SPIRAL COMPUTED TOMOGRAPHY ANGIOGRAPHY (SCTA) AND COLOR CODED DUPLEX ULTRASOUND (CCDUS): TWO COMPLEMENTARY DIAGNOSTIC TECHNIQUES FOR ASSESSMENT OF EXTRACRANIAL CEREBRAL ARTERY STENOSIS

Atherosclerotic lesions of the extracranial cerebral arteries account for ischemic stroke in over half of all cases. The risk of stroke associated with symptomatic carotid artery disease is related to the severity of the stenosis. Results of the two major clinical trials, North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST), showed that patients with symptomatic carotid artery disease may benefit from carotid endarterectomy. Therefore, detection and quantification of stenosis are essential. Discrepancies in the angiographic criteria used in both NASCET and ECST trials resulted in continued controversy about the most accurate method of measuring carotid artery stenosis. Moreover, to avoid complications related to the angiography procedure, a good evaluation of vessel wall and plaque composition need to be considered. Both SCTA and CCDUS are non invasive techniques that could overcome angiographic complications and give detailed information on stenosis grading and plaque characteristics. They have been used to evaluate carotid stenosis as a single or combined methods.     

Spiral computed tomography angiography (SCTA) and color coded duplex ultrasound (CCDUS): two complementary diagnostic techniques for assessment of extracranial cerebral artery stenosis

Atherosclerotic lesions of the extracranial cerebral arteries account for ischemic stroke in over half of all cases. The risk of stroke associated with symptomatic carotid artery disease is related to the severity of the stenosis. Results of the two major clinical trials, North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST), showed that patients with symptomatic carotid artery disease may benefit from carotid endarterectomy. Therefore, detection and quantification of stenosis are essential. Discrepancies in the angiographic criteria used in both NASCET and ECST trials resulted in continued controversy about the most accurate method of measuring carotid artery stenosis. Moreover, to avoid complications related to the angiography procedure, a good evaluation of vessel wall and plaque composition need to be considered. Both SCTA and CCDUS are non invasive techniques that could overcome angiographic complications and give detailed information on stenosis grading and plaque characteristics. They have been used to evaluate carotid stenosis as a single or combined methods.     

Carotid Artery Stent Placement Prior to Coronary Angioplasty or Coronary Bypass Graft Surgery

Patients with concomitant carotid and coronary artery disease are at high risk of both cardiac and cerebrovascular complications when they undergo revascularization procedures. The best management strategies for patients with concomitant disease have not been determined for certain. Staged surgical procedures with either coronary artery bypass grafting prior to carotid endarterectomy or vice versa appear to be associated with an increased risk of ischemic complications compared to separate procedures. Until recently, there were no convincing data favoring a simultaneous or combined revascularization approach. Carotid artery stenting has emerged as a treatment option in patients with cerebrovascular disease, even in the presence of a high cardiac risk. Recent results in patients with severe concomitant coronary artery disease are encouraging. This report focuses on the treatment of severe carotid artery stenosis by stent implantation in patients with life-threatening comorbidity to emphasize the possibility of this endovascular approach as an alternative treatment option.     

Asymptomatic carotid artery disease in the elderly. Diagnosis and management strategies

Carotid atherosclerosis is commonly detected in the asymptomatic elderly and in patients with known vascular disease in other distributions. Although there has been considerable interest in carotid bruits, they are not a reliable indicator of asymptomatic stenosis. In patients with asymptomatic stenosis detected by carotid ultrasound or angiography, the annual risk of ipsilateral infarction is approximately 1% to 2%. If ischemic events occur, they are usually transient ischemic attacks. Stroke risk is higher when there is progressive stenosis, stenosis exceeding 75% to 80%, and, possibly, complicated plaque-morphologic characteristics. The treatment of asymptomatic carotid stenosis remains controversial. Antiplatelet agents are of unproven value in asymptomatic patients. The role of surgical management is disputed because of uncertainties regarding the natural history of asymptomatic stenosis and the efficacy and complication rates of endarterectomy. Pending results of several ongoing randomized clinical trials, it may be advisable to withhold endarterectomy from those asymptomatic patients with stenosis of less than 75% to 80%. Prophylactic carotid endarterectomy is not necessary in the patient with asymptomatic stenosis who will undergo another operative procedure such as coronary artery bypass.     

Quantitative assessment of carotid stenosis: comparison between Doppler ultrasound, spiral computed tomography angiography, magnetic resonance angiography and digital angiography

BACKGROUND: The North American Symptomatic Carotid Endarterectomy Trial has confirmed the benefit of carotid endarterectomy in comparison to medical treatment in stroke prevention in symptomatic patients having a carotid stenosis of 70% or more. The Asymptomatic Carotid Atherosclerosis Study has concluded that the benefit of surgical treatment remains significant in asymptomatic patients with 60% (or more) stenosis of the ipsilateral internal carotid artery, when mortality rate remains inferior to 3%. In these two trials, angiography has been used to quantify the stenosis. Though this test is carrying some neurological and renal risks, replacing the angiography stenosis grading for a non or less invasive test, seems to be permissible. METHODS: In our retroprospective study, the assessments of the carotid stenosis by several non-invasive tests findings were compared to the angiography results. Nineteen carotid arteries of fifteen patients, both symptomatic and asymptomatic, having a carotid stenosis at least 60% or more and being detected by the Doppler ultrasound were explored either by magnetic resonance angiography (MRA), spiral computed tomography angiography (SCTA) and angiography. RESULTS: The ultrasonography and angiography findings were well correlated (r=0,88; p<0.002) according to the Spearman test. The assessments of the MRA were better correlated to the angiography than to the SCTA (respectively r=0.91, p<0.0001 and r=0,68, p<0.001). Using both ultrasonography and MRA as a confirmatory test, the rate of injustified carotid endarterectomy was 25%. And this rate rose up to 33% when the ultrasonography was used with the SCTA. It is noteworthy that negative predictive value of ARM was 100%. To reduce the mortality rate, several surgical teams managed the carotid stenosis without angiography. CONCLUSION: MRA could replace angiography, on condition that the rate of unjustified carotid endarterectomy lowers and becomes acceptable. Far reaching complementary studies are necessary to confirm the fiability of those non-invasive tests. In order to raise the benefit to carotid endarterectomy, the research studies should turn to the predictive score determination of a surgical international risk and towards the "High benefit" patients groups after endarterectomy.     

Asymptomatic carotid bruit.

Cerebrovascular events are responsible for high morbidity and mortality, and carotid atherosclerosis with vascular stenosis is a major etiological factor in cerebrovascular disease. Carotid bruit is an important marker of generalized atherosclerosis. On the basis of good quality studies, we can conclude that it indicates an increased risk of cerebrovascular events and acute myocardial infarction, with the degree of carotid stenosis and presence of ischemic heart disease as the most important predictive factors. Management can be medical (risk factor modification and antiplatelet therapy) or surgical (endarterectomy). In this review article we briefly discuss the management of asymptomatic carotid bruit based on the main studies published in the last few years addressing cardiovascular event prevention in carotid atherosclerosis.     

Symptomatic and asymptomatic carotid stenosis: just when we thought we had all the answers

The management of symptomatic and asymptomatic carotid stenosis has been a hotly debated topic for decades. The publication of four randomized controlled trials of carotid endarterectomy has clarified many of the issues. Patients with symptomatic carotid stenosis >70% benefit most with an absolute risk reduction of 17% over 2 years with numbers needed to treat of 3-6, whereas in patients with asymptomatic carotid stenosis >60%, the absolute risk reduction is 1% per annum (numbers needed to treat = 14-17). There is doubt about the benefit in women >70 years of age with asymptomatic stenosis. Carotid angioplasty and stenting is in its infancy and may one day supplant carotid endarterectomy as the treatment of choice; however, currently indications for this procedure include participation in randomized controlled trials, surgically inaccessible stenosis, in patients with combined symptomatic carotid and symptomatic coronary artery disease or in patients with severe co-morbidities that preclude formal carotid endarterectomy.     

Management of carotid artery stenosis: Comparing endarterectomy and stenting

Stroke ranks as the third leading cause of death, behind diseases of the heart and cancer. It is also the most important cause of disability. Approximately 750,000 people experience a stroke annually, costing an estimated $40 billion in direct and indirect costs. Approximately 25% of these ischemic events are related to occlusive disease of the cervical internal carotid artery. Carotid atherovascular stenosis increases the risk of ischemic stroke by acting as an embolic source, and causing hypoperfusion of the ipsilateral cerebral hemisphere. With some limitations, the North American Symptomatic Carotid Endarterectomy Trial (NASCET), European Carotid Surgery Trialists' Collaborative Group (ECST), and Asymptomatic Carotid Atherosclerosis Study (ACAS) have shown that carotid endarterectomy (CEA) substantially reduces the risk of stroke associated with certain grades of carotid stenosis. During the past few years, carotid angioplasty and stenting (CAS) has evolved as an alternative to CEA, particularly in patients who are known to have a higher complication rate with CEA.     

Asymptomatic carotid artery stenosis

Opinion statement Severe asymptomatic carotid stenosis is associated with a stroke risk of approximately 2% per annum. Aggressive management of risk factors is recommended, including cessation of smoking, and treatment of hypertension, diabetes, and hypercholesterolemia. Patients should be treated with antiplatelet agents. Carotid endarterectomy (CEA) in patients with greater than or equal to 60% stenosis reduces the risk of stroke by approximately 1% per annum overall. The benefit is greatest for men and younger patients. There may be no benefit for women or for older patients. Carotid angioplasty and stenting is not recommended as an alternative to CEA until there is clinical trial evidence of efficacy in asymptomatic stenosis, except in some patients with technical contraindications to CEA. There is no evidence that patients with asymptomatic severe carotid stenosis should undergo carotid revascularization prior to other surgical procedures, including coronary bypass surgery.     

Extracranial cerebrovascular disease

The prevention, management, and prognosis of patients with transient ischemic attack or stroke caused by extracranial cerebrovascular disease depend on the underlying pathophysiologic mechanisms involved. Atherosclerotic vascular disease is the predominant pathophysiologic mechanism. Management of this entity remains controversial and should be individualized. Recent data have clearly confirmed that carotid endarterectomy is better than medical therapy. Patients with a critically tight carotid stenosis appropriate in location to their symptoms are considered for carotid endarterectomy. This procedure should be performed only in the setting of excellent neuroradiologic support and surgical expertise, however, with a cumulative complication risk of less than 3%. Intimal dissection appears to be associated with a good prognosis with or without treatment. However, patients with symptoms should receive short-term therapy with antiplatelet or anticoagulant agents to prevent distal embolization. Corticosteroids are the drugs of choice for treatment of patients with extracranial arteritis. The presence of fibromuscular dysplasia in the cerebrovascular system has not proved to be a definitive risk for stroke or transient ischemic attack.     

Evolving treatment strategies for carotid artery stenosis

Opinion statement Internal carotid artery stenosis is an important cause of ischemic stroke. Treatment decisions frequently center on whether the patient is symptomatic or asymptomatic. For recently symptomatic patients with severe stenosis (70% to 99%) and low to medium surgical risk, carotid endarterectomy (CEA) is extremely useful for stroke prevention. CEA is moderately useful for patients with 50% to 69% symptomatic stenosis and is not indicated for patients with symptomatic stenosis of less than 50%. CEA may be useful for select patients with severe asymptomatic stenosis (80% to 99%) but only if the surgical complication is kept below the 3% level. Carotid stenting is an emerging option for the future but is still experimental. In addition to carotid intervention, patients with carotid stenosis should receive aggressive risk factor management, including treatment with antiplatelet agents and statins.     

Diabetes mellitus, Intima-Media-Dicke und Stenosen der A.?carotis

Atherosclerotic changes of the cerebral feeding arteries, beginning either as increased intima-media thickness (IMT) or as atherosclerotic plaques with subsequent lumen narrowing, are more frequent in diabetics than in non-diabetics. Although several pharmacological as well as non-pharmacological treatment options are available to reduce progression of inner-wall thickness, increased IMT alone is not an indication for pharmacological treatment. Patients, including diabetics, with asymptomatic carotid artery stenosis have an only slightly increased risk of ischemic stroke. Thus, primary preventive carotid endarterectomy (CEA) is justified only in the minority of cases. In contrast, patients with symptomatic carotid artery stenosis are at high risk of recurrence and should be treated early after the cerebrovascular event. CEA remains the gold standard for secondary prevention in these patients. Carotid stenting is only an alternative if the risk of periprocedural complications can be reduced.     

Carotid angioplasty and stenting versus carotid endarterectomy: randomized trial in a community hospital.

OBJECTIVES: The goal of this study was to determine whether carotid angioplasty and stenting (CAS) is equivalent to carotid endarterectomy (CEA) in patients with symptomatic carotid stenosis >70% by a randomized, controlled trial in a community hospital. BACKGROUND: Carotid angioplasty and stenting has been suggested to be as effective as CEA for treatment of symptomatic carotid artery stenosis. METHODS: A total of 104 patients presenting with cerebrovascular ischemia ipsilateral to carotid stenosis were selected randomly for CEA or carotid stenting and followed for two years. RESULTS: Stenosis decreased to an average of 5% after CAS. The patency of the reconstructed artery remained satisfactory regardless of the technique as determined by sequential ultrasound. One death occurred in the CEA group (1/51); one transient ischemic attack occurred in the CAS group (1/53); no individual sustained a stroke. The perception of procedurally related pain/discomfort was similar. Hospital stay was similar, although the CAS group tended to be discharged earlier (mean = 1.8 days vs. 2.7 days). Complications associated with CAS prolonged hospitalization when compared with those sustaining a CEA-related complication (mean = 5.6 days vs. 3.8 days). Return to full activity was achieved within one week by 80% of the CAS group and 67% of the patients receiving CEA. Hospital charges were slightly higher for CAS. CONCLUSIONS: Carotid stenting is equivalent to CEA in reducing carotid stenosis without increased risk for major complications of death/stroke. Because of shortened hospitalization and convalescence, CAS challenges CEA as the preferred treatment of symptomatic carotid stenosis if a reduction in costs can be achieved.     

Assessment of carotid intima-media thickness in subjects with ischemic cerebrovascular events undergoing endarterectomy

Background and aimIn clinical settings, the degree of lumen stenosis is the parameter used to select patients for carotid surgery. The present study was designed to measure carotid intima–media thickness (IMT), an indicator of atherosclerotic burden, in a sample of consecutive patients with ischemic cerebrovascular events referred for endarterectomy.Methods and resultsCarotid endarterectomy specimens from 55 consecutive patients (age 66 ± 10 years) admitted to hospital with recent documented atherothrombotic ischemic cerebrovascular events were compared with 24 carotid arteries from people (age 68 ± 11 years) who had died from documented causes unrelated to cerebrovascular disease. Measurement of extracranial carotid atherosclerosis was made from three anatomically defined segments, using image-processing software. A total of 426 cross sections was analyzed. Increasing IMT measures were clearly associated with increased risk of an ischemic event. Single maximum IMT values of 2.33 mm (95% CI, 1.69–2.96) for the common carotid, 2.45 mm (95% CI, 1.97–2.93) for the bifurcation, and 2.23 (95% CI, 1.83–2.64) for the internal carotid were associated with a 75% probability of a cerebrovascular ischemic accident. Receiver operator characteristic curve analyses demonstrated that the diagnostic ability of IMT measurements performed at the level of internal carotid artery to separate cases from controls was greater than common carotid artery or bifurcation measurements.ConclusionsThe present pathology study provides data on IMT in patients admitted to hospital for cerebrovascular accidents and referred for carotid endarterectomy.     

Management of Combined Severe Carotid and Coronary Artery Disease

Patients with severe carotid and coronary disease—especially if they require coronary artery bypass grafting (CABG)—are at high risk of cardiac events and stroke. Carotid revascularization should be considered for patients with symptomatic carotid disease and bilateral severe asymptomatic carotid stenosis. In patients with unilateral asymptomatic carotid stenosis, decision to proceed to revascularization should be based more on a perspective of long-term stroke prevention than of perioperative stroke reduction. Compared with endarterectomy, carotid artery stenting is associated with a lower incidence of periprocedural myocardial infarction, an event linked to long-term mortality. This observation may be particularly relevant for patients with advanced coronary artery disease such as those undergoing CABG. Irrespective of the carotid revascularization strategy, a broad disease management approach based on lifestyle modification and pharmacologic cardiovascular prevention is more likely to affect both the quality and duration of life than revascularization itself.     

Percutaneous treatment for carotid stenosis

Stroke is the leading cause of serious long-term disability in the United States. A substantial portion of strokes are caused by atherosclerotic carotid artery disease. The conventional risk factors for coronary atherosclerosis are also responsible for carotid atherosclerosis. Carotid stenosis is encountered in medical practice in either symptomatic or asymptomatic states. In symptomatic patients, medical management with antiplatelet agents does not provide adequate protection against stroke. Carotid endarterectomy can help reduce the risk of a subsequent stroke. Asymptomatic patients with severe carotid stenosis can also benefit from surgical intervention if endarterectomy can be performed at a low operative risk. In recent years, percutaneous carotid stenting using self-expanding stents has become popular for the treatment of carotid stenosis. Although this initial experience has been reported from a high-risk patient population, the results are encouraging, with acceptable periprocedural stroke rates. Moreover, emboli protection devices, modern adjuvant pharmacotherapy, and modern self-expanding stents were not utilized in these studies. With rapidly expanding technology and advances in interventional pharmacology, improvement of clinical outcome is likely. Table 3 summarizes current recommendations for carotid stenting based on a panel of cardiologists, radiologists, and vascular surgeons. At this stage, randomized trials to compare endarterectomy with carotid stenting are underway. Cautious optimism is necessary until the optimal equipment, emboli protection devices, and adjuvant pharmacotherapies are fully investigated. Until then, carotid stenting should be restricted to high-risk candidates for carotid endarterectomy, including patients with severe cardiac comorbidities, previous neck surgeries or radiation, restenosis after endarterectomy, or other technical contraindications for surgery.