preferences. It is critical that the patient understand that with intensive medical therapy the risk of stroke is relatively low, and the benefit of carotid revascularization is uncertain. We encourage patients with this degree of asymptomatic carotid stenosis to participate in ongoing randomized controlled trials comparing carotid revascularization with contemporary medical management, such as the CREST-2 trial [62]. Occlusion There is no role for revascularization to prevent recurrent stroke in the setting of complete carotid chronic occlusion. Intensive medical therapy is indicated. (See 'Intensive medical therapy and follow-up' above.) Alternative approaches The management of asymptomatic carotid atherosclerotic disease is controversial. The following strategies are advocated by different experts: Avoidance of carotid revascularization regardless of the degree of asymptomatic carotid stenosis, with reliance on intensive medical management as described above using statins, antiplatelet agents, treatment of hypertension and diabetes, and healthy lifestyle changes [63]. (See 'Intensive medical therapy and follow-up' above.) Intensive medical management for most patients, with carotid revascularization only for a subgroup of patients with asymptomatic carotid stenosis who have a particularly high risk of stroke [12,31]. This approach relies on the use of markers to determine high stroke risk, such as those with progression of carotid stenosis, the detection of asymptomatic carotid embolism, the presence of silent embolic infarcts, increased carotid plaque burden or high- risk plaque morphology, and reduced cerebrovascular reserve. Some vascular surgeons recommend medical therapy for stenosis <80 percent but recommend revascularization when stenosis exceeds 80 percent. (See 'Factors potentially associated with stroke risk' above.) Revascularization with CEA for most medically stable patients with asymptomatic carotid stenosis of 60 to 99 percent, rather than reserving CEA for more severe degrees of stenosis https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 12/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate (ie, 70 or 80 percent) [2,31,64]. This approach relies on prior data from randomized clinical trials, which showed a benefit in patients who were not receiving optimal medical therapy (see 'Carotid endarterectomy' below) without accounting for the uncertainty introduced by subsequent data, which show a lower risk of stroke with contemporary intensive medical therapy. For this reason, we advocate a more conservative approach. (See 'Intensive medical therapy and follow-up' above and 'Our approach to patient selection' above.) Patients unlikely to benefit from revascularization Patients unlikely to benefit from carotid revascularization include those with severe comorbidity due to other medical or surgical illnesses that increase their perioperative risk, limited life expectancy, a prior disabling ipsilateral stroke, or patients with total occlusion of the internal carotid artery (contraindication). Risk factors for morbidity and mortality associated with carotid revascularization techniques (ie, carotid endarterectomy, carotid artery stenting) should be evaluated to identify those who may face unacceptably high risk [65]. These risk factors are discussed separately. (See "Carotid endarterectomy", section on 'Preoperative evaluation' and "Overview of carotid artery stenting".) Most other asymptomatic atherosclerotic lesions affecting the inflow to the internal carotid artery or its outflow are best managed medically, including stenosis involving the brachiocephalic artery (ie, also not causing extremity symptoms or subclavian steal syndrome), the common carotid artery, or stenosis of the distal internal carotid artery beyond the bifurcation. Likewise, conditions causing asymptomatic nonatherosclerotic carotid stenosis (eg, fibromuscular dysplasia, dissection, vasculitis, or prior radiotherapy) are best managed medically. Choice of procedure The optimal carotid revascularization procedure, whether CEA or CAS, and for CAS, the optimal approach (transfemoral [TF-CAS] versus transcarotid artery revascularization [TCAR]) is controversial. However, there is agreement that the short-term (periprocedural) risk of stroke and death is generally higher with TF-CAS, while long-term outcomes are similar for CEA and CAS. The risk of stroke may be lower for TCAR compared with TF-CAS. (See 'Carotid endarterectomy' below and 'Carotid stenting' below.) Carotid endarterectomy Randomized controlled trials had found that CEA was beneficial for selected patients with asymptomatic internal carotid artery stenosis of 60 to 99 percent [51-53]. However, the absolute benefit was low. In addition, the evidence from these trials supporting CEA for asymptomatic carotid disease was less compelling for females compared with males. For those who are not already receiving antiplatelet therapy, treatment with aspirin (81 to 325 mg/day) is recommended for all patients who are having CEA. Aspirin should be started prior to https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 13/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate surgery and continued indefinitely for patients with asymptomatic atherosclerosis (see "Carotid endarterectomy", section on 'Antiplatelet therapy'). In addition, patients with atherosclerotic carotid disease, including those who undergo CEA, should receive intensive medical management that includes LDL-lower therapy and treatment of hypertension, cigarette smoking, and diabetes. (See 'Intensive medical therapy and follow-up' above and "Overview of secondary prevention of ischemic stroke".) Endarterectomy trials The efficacy of CEA, compared with no surgery, for patients with asymptomatic high-grade carotid stenosis was evaluated in three high-quality randomized controlled trials. These were the VA trial [51], ACAS [52], and ACST [53]. In a meta-analysis of these three trials, including 5268 subjects with a mean follow-up of 3.3 years per subject, CEA was associated with a 2.9 percent risk of perioperative stroke or death. CEA reduced the risk of any stroke, but the benefit was small with an overall absolute risk reduction of approximately one percent per year [54]; the corresponding number needed to treat (NNT) to prevent one stroke at three years was approximately 33. The outcome of any stroke or death was not significantly lower with CEA compared with medical therapy alone (20.5 versus 22.6 percent, relative risk [RR] 0.92, 95% CI 0.83-1.02). Findings of the individual CEA trials are as follows: The VA trial randomly assigned 444 males with 50 to 99 percent asymptomatic carotid stenosis to CEA plus aspirin or aspirin alone [51]. The mean duration of follow-up was 48 months. The incidence of stroke or TIA was significantly lower for the CEA plus aspirin group compared with the aspirin alone group (8 versus 21 percent, RR 0.38, 95% CI 0.22- 0.67) ( figure 1). The difference in incidence for ipsilateral stroke was nonsignificantly lower for the CEA plus aspirin group (4.7 versus 9.4 percent). The composite outcome of all stroke and death at 30 days and 48 months was similar (41 and 44 percent, respectively); most of the deaths were due to coronary heart disease. This trial was criticized for including TIA in the primary endpoint, since by definition TIA does not result in any persistent neurologic deficit [55]. The ACAS trial randomized 1662 adults with 60 to 99 percent asymptomatic carotid stenosis to CEA plus aspirin (325 mg/day) or aspirin alone [52]. At a median follow-up of 2.7 years, the incidence of ipsilateral stroke and any perioperative stroke or death was lower for the CEA plus aspirin group compared with the aspirin group (5 versus 11 percent; RR 0.53, 95% CI 0.22-0.72). The incidence of major ipsilateral stroke, major perioperative stroke, and perioperative death was nonsignificantly lower for the CEA plus aspirin group (3.4 versus 6 percent) ( figure 2). This study was not powered to determine sex https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 14/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate differences. However, subgroup analysis suggested that CEA was less effective in females. Males had an absolute risk reduction of 8 percent, whereas the absolute risk reduction in females was only 1.4 percent, perhaps due to a higher incidence of perioperative complications in females compared with males (3.6 versus 1.7 percent). The ACST trial randomly assigned 3120 patients with 60 percent asymptomatic carotid stenosis to immediate CEA or to deferred CEA (until a definite indication occurred) [53,66]. The main analysis for ACST combined ipsilateral and contralateral strokes [67]. In the immediate CEA group, one-half were treated with CEA by one month and 88 percent by one year. In the deferred CEA group, approximately 4 percent of patients per year underwent CEA. At a mean of 3.4 years of follow-up, the five-year risk for all strokes or perioperative death in the immediate CEA group was reduced compared with deferred CEA group (6.4 versus 11.8 percent, absolute risk reduction [ARR] 5.4 percent, 95% CI 2.96-7.75) ( figure 3). Benefit with immediate CEA was also found for fatal or disabling stroke (3.5 versus 6.1 percent). Approximately one-half of the strokes in the trial were fatal or disabling ( figure 4). The CEA group had a perioperative risk of stroke or death of 3.1 percent within 30 days of surgery. The ACST subgroup analyses reported the results of risk reduction for non-perioperative stroke (ie, the benefit) separately from perioperative risk (ie, the risk) but did not report the overall balance of benefit and risk, which is of most importance to patients and clinicians [68]. While CEA was beneficial for preventing non-perioperative stroke in the entire cohort, the risk reduction over five years was significant for males (ARR 8.2 percent, 95% CI 5.64- 10.78) but not females (ARR 4.1 percent, 95% CI 0.74-7.41). The benefit of CEA was maintained at long-term follow-up (median nine years) in the ACST cohort [66]. The risk for all stroke or perioperative death in the immediate CEA group was significantly reduced compared with the deferred CEA group at five years (6.9 versus 10.9 percent) and at 10 years (13.4 versus 17.9 percent). Factors influencing outcome Delay to benefit CEA for patients with asymptomatic carotid atherosclerosis is a long- term investment [53]. The ACAS and especially the ACST trials showed that the net benefit of CEA is delayed for many months to nearly two years because of perioperative morbidity. In the ACST, the net benefit of CEA was delayed for approximately two years after surgery ( figure 3) [53,66]. (See 'Endarterectomy trials' above.) Perioperative complications CEA for patients with asymptomatic carotid atherosclerosis should be performed only at institutions in which the perioperative stroke and death rate is https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 15/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate <3 percent. Combined morbidity and mortality that exceed 3 percent could eliminate the small benefit gained from revascularization for patients with asymptomatic carotid disease [69-71]. Surgeons participating in the ACAS trial were required to have a perioperative complication rate of <3 percent in asymptomatic patients [72]. Similarly, the ACST reported a 3.1 percent perioperative complication rate [53]. (See 'Endarterectomy trials' above.) A review of Medicare recipients undergoing CEA found a higher mortality rate in hospitals that did not participate in major carotid surgery trials, particularly in those centers performing fewer procedures (2.9 percent, versus 1.4 percent in North American Symptomatic Carotid Endarterectomy Trial [NASCET] and ACAS trial hospitals) [73]. Low patient volume (less than three CEAs performed every two years) and a greater number of years since licensure of the surgeon have also been associated with worse outcomes following CEA [74]. (See 'Endarterectomy trials' above.) Sex The potential benefit of CEA may be greater for males compared with females with asymptomatic carotid disease. Nevertheless, we use the same approach for managing asymptomatic carotid stenosis regardless of sex, but include a discussion of the difference in the data when counseling female patients. A meta-analysis of data from the ACAS and ACST trials ( figure 5) found no benefit for females with respect to the five-year risk of any stroke or perioperative death (odds ratio [OR] 0.96, 95% CI 0.63-1.45) [68]. By contrast, there was significant benefit for males (OR 0.49, 95% CI 0.36-0.66). In the ACST trial, the benefit of surgery for females with asymptomatic carotid disease was reported as significant, although less robust than the benefit for males [53]. However, this analysis excluded perioperative events. The 10-year data from ACST found a similar benefit for the outcome of any stroke or perioperative death for males and females <75 years of age (males: ARR 5.5 percent, 95% CI 0.9-10.0; females: ARR 5.8 percent, 95% CI 0.1-11.4). In addition, a cohort study that included over 1.2 million patients treated primarily with CEA (but also CAS) from 2005 to 2015 reported no difference in outcome for asymptomatic carotid stenosis in males versus females [75]. Carotid stenting Although overall outcomes with CAS have improved over time, CEA remains the preferred method of revascularization for most patients with asymptomatic carotid atherosclerosis with standard surgical risk. Based upon the data from randomized trials comparing CEA with predominantly carotid artery stents placed using a transfemoral approach (ie, TF-CAS), we suggest not treating asymptomatic carotid disease with CAS unless both of the following conditions are met (see 'Stenting versus endarterectomy trials' below): https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 16/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate The patient's anatomy or risk factors suggest a prohibitively high risk for CEA The local center and operator have demonstrated a low (<3 percent) periprocedural risk The available evidence suggests that CAS and CEA provide similar long-term outcomes for patients with asymptomatic and symptomatic carotid occlusive disease, but the periprocedural risk of stroke and death has been higher with TF-CAS. An alternative to TF-CAS, TCAR uses a neck incision to deliver the stent directly into the carotid artery, which avoids passing wires and catheters across the aortic arch and possibly reduces the risk for embolism. Observational data suggest that TCAR has a lower risk of perioperative stroke or death compared with TF-CAS. However, there are no trials directly comparing these techniques. The approach to CAS, including a comparison of transfemoral and transcarotid carotid stenting and their advantages and disadvantages, is reviewed separately. (See "Overview of carotid artery stenting".) Most major guidelines note that the advantage of revascularization with CAS over intensive medical therapy alone is not well established for patients with asymptomatic carotid disease [2,31,57,64]. Nevertheless, some experts consider CAS as an alternative to CEA for the treatment of patients with asymptomatic carotid atherosclerotic disease, particularly in patients younger than age 70 years who are considered to be poor candidates for surgery due to high risks for perioperative complications. Risk factors for periprocedural complications of CAS are discussed separately. (See "Overview of carotid artery stenting".) Stenting versus endarterectomy trials Most clinical trial data regarding carotid stenting compared CEA with CAS in patients with either symptomatic or asymptomatic carotid disease. These trials suggest that the periprocedural (30-day) stroke or death rate is higher with TF-CAS compared with CEA, while the risk of stroke or death beyond 30 days is similar for both techniques [76,77]. A 2017 meta-analysis of five trials (ACT1, CREST, EVA-3S, ICSS, SAPPHIRE) compared CEA with CAS in 6526 patients with symptomatic or asymptomatic carotid disease [76]. In a subgroup analysis limited to patients with asymptomatic carotid disease, the risk of any periprocedural stroke was higher for CAS compared with CEA (2.8 versus 1.6 percent, OR 1.86, 95% CI 1.05-3.31). However, the risk of periprocedural stroke plus ipsilateral stroke during long-term follow-up was similar for CAS and CEA (5.3 versus 4.5 percent, OR 1.26, 95% CI 0.86- 1.84). The composite outcome of death, stroke, or myocardial infarction during the periprocedural period plus ipsilateral stroke during long-term follow-up was also similar for CAS and CEA (6.0 versus 8.2 percent, OR 0.92, 95% CI 0.68-1.26) [76]. No randomized trials have compared CAS (TF-CAS or TCAR) with medical therapy alone. Note that the trials discussed below have involved TF-CAS. Data regarding TCAR or other approaches https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 17/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate to CAS are reviewed separately. (See "Overview of carotid artery stenting", section on 'Approach to carotid artery stenting'.) The ACST-2 trial, conducted from 2008 to 2020, randomly assigned 3625 patients with asymptomatic carotid stenosis of 70 to 99 percent to either CAS or CEA in a 1:1 ratio [78]. The procedural (ie, 30-day) rate of death or any stroke was higher with CAS compared with CEA (3.7 versus 2.7 percent), but the difference was not statistically significant. The five- year rate of procedural death or any stroke during follow-up was also higher with CAS compared with CEA (8.6 versus 7.1 percent), but again the difference did not achieve statistical significance. These results largely reflected a slightly higher incidence of nondisabling stroke in the CAS group; the five-year rate of procedural death or any fatal or disabling stroke was similar for CAS and CEA (3.3 versus 3.5 percent). The ACT I trial, halted early due to slow recruitment, randomly assigned 1453 patients with asymptomatic carotid stenosis of 70 to 99 percent to either CAS or CEA in a 3:1 ratio [79]. For the primary composite endpoint (death, stroke, or myocardial infarction within 30 days after the procedure or ipsilateral stroke within one year), event rates for CAS and CEA were 3.8 and 3.4 percent, respectively, achieving the prespecified statistical margin for noninferiority of CAS compared with CEA. The rates of stroke or death within 30 days for CAS and CEA were 2.9 and 1.7 respectively, and the difference was not statistically significant. The CREST trial randomly assigned 2502 patients with carotid atherosclerotic disease to endarterectomy or stenting [80,81]. The proportion of enrolled patients with asymptomatic and symptomatic carotid disease was 47 and 53 percent, respectively. The overall effectiveness and safety of CAS and CEA were similar, and the benefits were equal for males and females and for patients with asymptomatic and symptomatic carotid disease. The primary endpoint for the trial, a composite of any stroke, myocardial infarction, or death within 30 days following treatment plus any ipsilateral stroke during 10-year follow- up (median 2.5 years), was similar for CAS and CEA (11.8 versus 9.9 percent, hazard ratio [HR] 1.11, 95% CI 0.83-1.44). In addition, the overall rate of ipsilateral stroke, including the periprocedural period through 10 years of follow-up, was similar for CAS and CEA (10.8 versus 7.9 percent, HR 1.33, 95% CI 0.98-1.80). However, there was a clear trade-off, with higher rates of perioperative stroke or death (and lower rates of perioperative myocardial infarction) for CAS compared with CEA. A CREST substudy found that at one year, stroke had a large detrimental impact on quality of life, while both MI and cranial nerve palsy had small impacts on quality of life that were not statistically significant [82]. Despite the higher rate of stroke with CAS, there were no differences at one year after the procedure between the CEA and CAS groups in any quality-of-life measure. https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 18/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate The SAPPHIRE trial compared CAS with CEA in patients considered at high risk for surgery due to clinically significant cardiac disease, severe pulmonary disease, contralateral carotid occlusion, contralateral laryngeal nerve palsy, previous radical neck surgery, cervical radiation therapy, recurrent stenosis after CEA, and age greater than 80 years [83,84]. SAPPHIRE randomly assigned 334 patients to CAS or CEA and enrolled symptomatic patients with 50 percent carotid stenosis or asymptomatic patients with 80 percent carotid stenosis. More than 70 percent of patients had asymptomatic carotid disease. At one year, CAS was not inferior to CEA [83]. The primary endpoint was the cumulative incidence of periprocedural (30 day) death, stroke, or myocardial infarction, and/or death or ipsilateral stroke between 31 days and one year. There was near significant reduction in the primary composite endpoint for CAS compared with CEA (12.2 versus 20.1 percent, absolute difference 7.9 percent, 95% CI -0.7 to 16.4 percent). At three years, follow-up data was available for 78 percent of the subjects. The major secondary endpoint (ie, primary endpoint events plus death or ipsilateral stroke between one and three years) was similar for CAS compared with CEA (24.6 versus 26.2 percent) [85]. A number of methodologic and statistical problems with SAPPHIRE have made the conclusions problematic and controversial, with bias that favored the CAS group [65,86-89]. In addition, the periprocedural complication rates in both the CAS and CEA treatment groups were higher than the recommended rate of 3 percent [2,64], which might negate any potential advantages of CAS. Despite these shortcomings, the conclusion that CAS is not inferior to CEA in patients with asymptomatic disease is probably valid for the patient group that was studied, that is, those considered "high risk" for carotid surgery [86]. Stenting in specific subgroups Older adults appear to have worse outcomes with CAS than with CEA [90-92], even though older age was originally proposed to be a condition associated with high surgical risk and therefore a potential indication for stenting rather than endarterectomy. In the prospective CREST trial, the rate of poor outcome in patients age 70 and older was higher with stenting than with endarterectomy [90]. (See 'Stenting versus endarterectomy trials' above.) In a meta-analysis of 41 studies in patients 80 years old, the relative risks of death or myocardial infarction at 30 days were similar for patients having CAS or CEA, but the stroke rate was significantly higher for CAS (7.0 percent, versus 1.9 percent for CEA) [91]. Based upon an acceptable 3 percent stroke rate at 30 days, the pooled RR for stroke was more than threefold higher after CAS (RR 2.18 versus 0.63 with CEA). Most of the included studies were retrospective, so the results of this meta-analysis are not definitive. https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 19/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate A 2022 patient-level meta-analysis, which included 2544 patients from two large randomized trials (ACT1, CREST), found that in patients younger than 80 years of age with >70 percent asymptomatic stenosis, periprocedural adverse events were similar in TF-CAS and CEA including: any stroke (2.7 and 1.5 percent); death (0.1 and 0.2 percent); and any stroke/death (2.7 and 1.6 percent) [93]. The rate of ipsilateral stroke after the periprocedural period was also similar (2.3 and 2.2 percent). These data suggest that TF-CAS may be a reasonable treatment option for patients who are younger than 80 years old. In data drawn largely from registries and case series, subgroups suggested to have tolerated CAS with relative safety included patients with prior neck irradiation, high cervical carotid bifurcations, and those with complete occlusion of the contralateral internal carotid artery. Further evidence from large controlled clinical trials is needed before drawing firm conclusions about the safety and effectiveness of CAS in these various subgroups. (See "Overview of carotid artery stenting", section on 'Risk assessment'.) SOCIETY GUIDELINE LINKS Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Stroke in adults" and "Society guideline links: Occlusive carotid, aortic, renal, mesenteric, and peripheral atherosclerotic disease".) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 20/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate Basics topics (see "Patient education: Carotid artery disease (The Basics)" and "Patient education: Atherosclerosis (The Basics)") SUMMARY AND RECOMMENDATIONS Definition and implications Asymptomatic carotid atherosclerotic disease refers to the presence of atherosclerotic narrowing of the extracranial internal carotid artery in individuals without a history of ipsilateral carotid territory ischemic stroke or transient ischemic attack in the last six months. The most feared outcome of carotid atherosclerosis is ischemic stroke. The estimated risk of ipsilateral stroke in patients with asymptomatic carotid atherosclerosis (stenosis 50 percent) is approximately 0.5 to 1.0 percent annually. Asymptomatic carotid atherosclerosis is also a marker of increased risk for myocardial infarction and vascular death. (See 'Extracranial carotid atherosclerosis' above.) Intensive medical therapy for all patients All patients with carotid stenosis should receive intensive medical therapy to reduce the risk of future stroke and myocardial infarction. These interventions include antiplatelet and statin therapy and other measures to address risk factors for atherosclerosis. Specific recommendations are discussed separately. (See 'Intensive medical therapy and follow-up' above and "Overview of secondary prevention of ischemic stroke" and "Long-term antithrombotic therapy for the secondary prevention of ischemic stroke" and "Overview of primary prevention of cardiovascular disease".) Role of revascularization The approach to asymptomatic carotid stenosis due to atherosclerosis depends upon the severity of stenosis and the comorbid conditions and life expectancy of the patient. In addition, the local experience of the center and surgeon or interventionalist is important if carotid revascularization is desired. (See 'Role of carotid revascularization' above.) Less than 50 percent stenosis Patients with asymptomatic internal carotid artery atherosclerotic disease with <50 percent carotid artery stenosis do not require carotid revascularization. (See 'Stenosis less than 50 percent' above.) Fifty to 69 percent stenosis For patients with asymptomatic carotid atherosclerotic disease with 50 to 69 percent carotid artery stenosis, we suggest no revascularization procedure (Grade 2C). Patients should be managed with intensive medical therapy alone and followed with interval surveillance carotid ultrasound imaging. (See 'Stenosis 50 to 69 percent' above.) https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 21/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate Seventy to 99 percent stenosis For medically stable patients with a severe 70 to 99 percent asymptomatic carotid stenosis, either intensive medical therapy alone or intensive medical therapy plus carotid revascularization are reasonable. For patients to potentially benefit from carotid revascularization, their life expectancy should be at least five years, and the combined perioperative risk of stroke and death should be 3 percent. We advise a shared decision-making approach that incorporates the patient's values and preferences. Patients must understand both that the risk of stroke with intensive medical therapy is relatively low and that the benefits of carotid revascularization are limited. We encourage patients with asymptomatic carotid stenosis of 70 to 99 percent to participate in ongoing randomized controlled trials comparing carotid revascularization with modern medical management. (See 'Stenosis 70 to 99 percent' above and 'Carotid endarterectomy' above and 'Factors influencing outcome' above.) Endarterectomy compared with stenting Carotid artery angioplasty and stenting (CAS) and carotid endarterectomy (CEA) provide similar long-term outcomes for patients with carotid occlusive disease, but the periprocedural risk of stroke and death is higher with transfemoral carotid artery stenting (TF-CAS) compared with CEA. The periprocedural risk may be lower for transcarotid artery revascularization (TCAR) compared with TF-CAS. TF-CAS should generally be reserved for patients with unacceptably high surgical risk and performed only in centers with demonstrated low (<3 percent) periprocedural risk for combined stroke and death. (See 'Carotid stenting' above.) ACKNOWLEDGMENTS The UpToDate editorial staff acknowledges Ronald M Fairman, MD, who contributed to an earlier version of this topic review. The UpToDate editorial staff also acknowledges Emile R Mohler, III, MD (deceased), who contributed to an earlier version of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. de Weerd M, Greving JP, Hedblad B, et al. Prevalence of asymptomatic carotid artery stenosis in the general population: an individual participant data meta-analysis. Stroke https://www.uptodate.com/contents/management-of-asymptomatic-extracranial-carotid-atherosclerotic-disease/print 22/35 7/5/23, 11:40 AM Management of asymptomatic extracranial carotid atherosclerotic disease - UpToDate 2010; 41:1294. 2. Meschia JF, Bushnell C, Boden-Albala B, et al. Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2014; 45:3754. 3. 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