Cerebrovascular Disease: Natural History, Diagnostic Evaluation, Plaque, and Medical Therapy

29.1Natural history and stroke-risk framing

Cerebrovascular disease must be framed first as a time-dependent risk problem, not simply as a stenosis measurement. The same carotid lesion carries very different implications in a patient seen days after an ipsilateral hemispheric TIA than in a patient with an incidental bruit and no neurological symptoms. Modern management therefore begins by classifying the patient as symptomatic or asymptomatic, defining the qualifying event, measuring stenosis with a reproducible method, and estimating whether the patient’s early stroke risk is high enough to justify procedural risk in addition to intensive medical therapy. The 2011 multisociety carotid and vertebral guideline established the broad intervention envelope for extracranial carotid disease, while later SVS, ESVS, and AHA/ASA guidance refined threshold language and embedded carotid decisions within secondary prevention pathways Editor's Choice European 2023 · SVS 2022 · AHA 2021 · ACC/AHA 2011 · AHA/ASA secondary stroke prevention 2021 · CREST-2 protocol 2017.

The most secure natural-history signal remains recent ipsilateral symptoms with severe carotid stenosis. In NASCET, patients with recent ipsilateral TIA or minor stroke and 70–99% stenosis by the NASCET method had a 2-year ipsilateral stroke risk of 26% on medical therapy, reduced to 9% with carotid endarterectomy. That 17 percentage-point absolute reduction explains why symptomatic severe stenosis is not managed as a routine outpatient plaque problem; it is a high-risk, time-sensitive syndrome in which neurological stability, infarct burden, operative risk, and speed of work-up determine whether benefit is preserved Endarterectomy symptomatic carotid 2004 · NASCET · 1991.

Moderate symptomatic stenosis is less forgiving of imprecision. For 50–69% symptomatic stenosis, NASCET showed a smaller absolute benefit over 5 years, with benefit concentrated in selected subgroups, particularly men and patients treated within a few weeks of the qualifying event. The practical implication is that moderate stenosis should not be rounded upward, treated reflexively, or judged from a single technically limited duplex report; the surgeon must confirm measurement method, symptom laterality, timing, sex-specific and clinical modifiers, and competing stroke mechanisms before recommending intervention Endarterectomy symptomatic carotid 2004 · NASCET · 1991.

Timing is central to the natural history of symptomatic carotid disease. The pooled NASCET/ECST analysis showed that carotid endarterectomy delivers its largest absolute benefit when performed within 2 weeks of the qualifying event. In the same pooled evidence base, the approximate number needed to treat to prevent one ipsilateral stroke was 5 when surgery occurred within 2 weeks, compared with approximately 125 when delayed beyond 12 weeks. Late operation may still benefit selected patients, but delay converts a high-yield preventive operation into a marginal one unless the patient remains at ongoing risk Endarterectomy symptomatic carotid 2004 · Randomised trial endarterectomy 1998 · NASCET · 1991.

The early hazard after TIA or minor stroke is not merely a historical artifact. The international TIA registry found that most recurrent strokes after TIA or minor stroke occurred within the first 90 days, even in contemporary rapid-access settings. EXPRESS similarly demonstrated that urgent assessment and immediate secondary prevention after TIA or minor stroke reduced early recurrent stroke compared with delayed standard-care pathways. For the vascular surgeon, this means a carotid referral after a transient neurological event should trigger a pathway, not an appointment queue: brain imaging, vascular imaging, antithrombotic initiation, statin therapy, blood-pressure management, mechanism classification, and procedural planning must proceed in parallel One-Year Risk Stroke 2016 · EXPRESS study 2007.

Asymptomatic carotid stenosis has a different evidentiary profile. ACAS reported that, in patients with asymptomatic stenosis of 60% or greater, 5-year aggregate stroke risk was approximately 11.0% with medical therapy and 5.1% after carotid endarterectomy, but that result came from an era of less intensive medical therapy. ACST-1 long-term follow-up supported durable stroke reduction after successful endarterectomy, while also showing that benefit depends on perioperative risk being kept low and on long enough life expectancy for the modest absolute reduction to accrue Endarterectomy asymptomatic carotid 1995 · ACST-1 (10-year) 2010.

The perioperative-risk requirement is especially strict in asymptomatic disease. ACST-1 reported an approximately 3.0% 30-day perioperative stroke or death rate in the immediate-CEA arm, and contemporary ESVS guidance frames an approximately 3% 30-day stroke or death cap as the quality threshold for asymptomatic carotid intervention. If a center cannot reproduce such outcomes, the natural-history advantage of prophylactic intervention erodes; the patient then assumes immediate procedural risk for a future stroke risk that may already be reduced by contemporary medical therapy ACST-1 (10-year) 2010.

Guidelines diverge most visibly in asymptomatic stenosis because the baseline event rate has fallen and because plaque vulnerability, life expectancy, procedural risk, and patient preference modify the decision. SVS 2022 frames asymptomatic carotid endarterectomy as indicated for stenosis of approximately 70% or greater by validated imaging when life expectancy and surgical risk are acceptable. ESVS 2023 is more selective and emphasises plaque morphology and other risk features as co-modifiers, while the CREST-2 evidence program directly tests intensive medical management against revascularization strategies in high-grade asymptomatic disease SVS 2022 · CREST-2 medical management 2026 · CREST-2 protocol 2017.

Medical therapy has changed the natural history of both symptomatic and asymptomatic disease. For patients with recent stroke or TIA without known coronary heart disease, SPARCL showed that atorvastatin 80 mg daily reduced 5-year recurrent stroke risk, with recurrent stroke rates of approximately 11.2% on atorvastatin versus 13.1% on placebo. The small hemorrhagic stroke signal in SPARCL is a reminder that “best medical therapy” is not a slogan; it is individualized antiplatelet therapy, lipid therapy, blood-pressure control, smoking cessation, diabetes care, lifestyle change, and mechanism-directed management SVS 2022 · High-Dose Atorvastatin after 2006.

Short-course dual antiplatelet therapy is part of the early-risk strategy after selected minor stroke or high-risk TIA, but it is not indefinite carotid medical therapy. CHANCE randomized Chinese patients with minor stroke or high-risk TIA to 21 days of clopidogrel plus aspirin versus aspirin alone and reduced 90-day recurrent stroke. POINT extended the evidence base mainly in North American sites using 90 days of clopidogrel plus aspirin, reducing major ischemic events but increasing major hemorrhage, with net benefit concentrated early. MATCH, by contrast, showed that 18 months of clopidogrel plus aspirin after recent ischemic stroke or TIA did not lower recurrence and increased life-threatening bleeding compared with clopidogrel alone Clopidogrel Aspirin Acute 2018 · Clopidogrel Aspirin Acute 2013 · Aspirin clopidogrel compared 2004.

Stroke-risk framing should therefore be explicit in every consultation note. A useful formulation is: neurological event and date; symptom laterality; stenosis percentage and measurement method; confirmatory imaging status; competing mechanisms; current antithrombotic and statin therapy; blood-pressure trajectory; life expectancy; estimated perioperative stroke or death risk; and whether intervention can occur inside the evidence-supported time window. This discipline prevents the common error of treating all carotid stenoses as equivalent and aligns the vascular plan with AHA/ASA source-mechanism classification and integrated secondary prevention Editor's Choice European 2023 · SVS 2022 · ACC/AHA 2011.

29.2Clinical and imaging diagnosis of carotid disease

The diagnosis of clinically important carotid disease begins with the neurological history, not with the duplex image. The surgeon must establish whether the patient had a retinal or cerebral ischemic event, whether symptoms were ipsilateral to the suspected carotid lesion, whether the event was disabling or non-disabling, and how much time has elapsed since onset. This classification determines whether the stenosis is symptomatic, whether the early recurrent-stroke window is still open, and whether procedural benefit is likely to outweigh risk.

A recent TIA or minor stroke should be treated as an urgent diagnostic episode. Contemporary rapid-access pathways have reduced but not abolished recurrence risk; the international TIA registry reported a one-year stroke risk of about 5% under urgent-evaluation conditions, and most recurrent events clustered in the first 90 days. The public-health rationale is substantial because stroke remains a leading cause of long-term disability in the United States, but the bedside point is narrower: delays in imaging, source classification, and secondary prevention are clinically meaningful One-Year Risk Stroke 2016 · AHA 2023.

Initial assessment should document vascular territory and competing mechanisms. A hemispheric motor or language event, an ipsilateral retinal ischemic event, and a posterior-circulation syndrome imply different arterial questions. The AHA/ASA secondary-prevention guideline emphasises mechanism classification—cardioembolic, large-artery atherosclerosis, small-vessel, cryptogenic—as the gate to tailored antithrombotic and risk-factor strategy. A carotid stenosis discovered after stroke is not automatically causal; it must match the clinical syndrome and imaging pattern.

Carotid duplex ultrasound is the usual first vascular test, but an abnormal duplex is not the final operative map. ESVS 2023 and SVS 2022 frame imaging as a stepwise commitment: a non-trivial duplex abnormality should prompt confirmatory cross-sectional imaging with CTA or MRA before intervention is offered. This approach reduces the risk of operating on a misclassified lesion, clarifies tandem disease, and gives the surgeon information that duplex cannot reliably provide in all patients SVS 2022.

CTA and MRA are confirmatory studies, not merely redundant images. They help characterise the aortic arch, common carotid origin, cervical internal carotid lesion, distal internal carotid artery, intracranial circulation, and diagnostic ambiguity when duplex is technically limited. The modality choice depends on renal function, contrast allergy, implants, local expertise, and urgency; the management requirement is that the final treatment decision rest on imaging adequate to define stenosis severity, anatomy, and the likely stroke mechanism.

The imaging report must specify stenosis severity in clinically usable terms. Severe symptomatic stenosis by NASCET convention is 70–99%, while moderate symptomatic stenosis is 50–69%; these categories are tied to trial-derived benefit and should not be blurred. ECST used a different measurement method, and an ECST percentage is not interchangeable with a NASCET percentage. When outside imaging is imported into a vascular practice, the surgeon should verify how the measurement was made before translating it into a procedural recommendation Endarterectomy symptomatic carotid 2004 · Randomised trial endarterectomy 1998 · NASCET · 1991.

Brain imaging and vascular imaging should be interpreted together. A non-disabling event with an ipsilateral severe carotid stenosis and no stronger competing mechanism is a different problem from a large completed infarct, a lacunar syndrome, or a cardioembolic pattern with an incidental carotid plaque. The AHA/ASA secondary-prevention pathway places carotid intervention within a broader sequence of antiplatelet therapy, statin initiation, blood-pressure control, and source-mechanism work-up, rather than treating revascularization as a stand-alone event.

The diagnostic conclusion should be written as a decision, not as a test list. A complete note states whether the patient is symptomatic or asymptomatic, the qualifying event and date, the ipsilateral artery, the stenosis category and measurement method, whether confirmatory CTA/MRA has been obtained, whether the brain imaging supports large-artery disease, and what medical therapy has already been started. This structure protects the patient from both under-treatment of high-risk symptomatic stenosis and over-treatment of incidental plaque.

Antithrombotic decisions are made while the diagnostic work-up proceeds. In selected minor stroke or high-risk TIA, short-course dual antiplatelet therapy has evidence from CHANCE and POINT, while THALES provides an evidence lane for ticagrelor plus aspirin for 30 days in mild-to-moderate stroke or high-risk TIA, reducing stroke or death at the cost of more severe bleeding. These regimens should not delay imaging or source classification, and they do not substitute for definitive evaluation of a symptomatic high-grade carotid lesion Ticagrelor Aspirin Aspirin 2020 · Clopidogrel Aspirin Acute 2018 · Clopidogrel Aspirin Acute 2013.

29.3Plaque morphology, stenosis severity, and medical therapy

Plaque morphology matters because stenosis percentage alone does not fully describe stroke risk, especially in asymptomatic disease. ESVS 2023 emphasises imaging-defined plaque morphology as a co-modifier of intervention indication for asymptomatic carotid stenosis, alongside stenosis severity. The practical message is not that every irregular plaque requires intervention, but that the surgeon should avoid reducing asymptomatic risk assessment to a single percentage when guideline-supported morphology and patient-level factors are available.

Severity remains the backbone of evidence-based decision-making. The strongest symptomatic evidence attaches to 70–99% NASCET-method stenosis, where endarterectomy produced a large 2-year ipsilateral stroke reduction. Moderate symptomatic stenosis, 50–69%, requires more selective judgment because benefit is smaller and subgroup-sensitive. Asymptomatic stenosis thresholds are more controversial because the historical benefit from ACAS and ACST-1 occurred under older medical-therapy conditions and must be reinterpreted in the contemporary era Endarterectomy symptomatic carotid 2004 · Endarterectomy asymptomatic carotid 1995 · NASCET · 1991 · ACST-1 (10-year) 2010.

The asymptomatic plaque discussion should begin with medical therapy, not with a consent form. SVS 2022 frames antiplatelet therapy, statin therapy, blood-pressure control, and lifestyle modification as the foundation of care for extracranial cerebrovascular disease. AHA/ASA primary-prevention guidance similarly frames stroke prevention around blood-pressure control, lipid management, smoking cessation, glycaemic control, and selected antiplatelet therapy, while the AHA/ASA secondary-prevention guideline owns post-event risk-factor strategy. These measures are not “non-operative care”; they are the baseline therapy against which any prophylactic procedure must prove incremental benefit SVS 2022 · AHA 2014.

Urgency changes the medical-therapy sequence after TIA or minor stroke. EXPRESS demonstrated that urgent assessment and immediate secondary prevention reduced early recurrent stroke compared with delayed standard-care pathways. This supports a vascular service model in which the same referral triggers antiplatelet therapy when appropriate, statin intensification, blood-pressure review, source-mechanism work-up, and expedited imaging rather than waiting for a revascularization decision before acting EXPRESS study 2007.

High-intensity statin therapy has cerebrovascular-specific trial support. In SPARCL, atorvastatin 80 mg daily after recent stroke or TIA reduced recurrent stroke over 5 years, with recurrent stroke rates of approximately 11.2% on atorvastatin and 13.1% on placebo. The hemorrhagic stroke signal requires individualized discussion, but it should not obscure the broader point that lipid therapy is a core carotid treatment, not a perioperative adjunct High-Dose Atorvastatin after 2006.

Dual antiplatelet therapy should be time-limited and indication-specific. CHANCE supports 21 days of clopidogrel plus aspirin after minor stroke or high-risk TIA in the studied population, POINT supports early ischemic benefit with 90 days of clopidogrel plus aspirin but with increased major hemorrhage, and THALES supports 30 days of ticagrelor plus aspirin in mild-to-moderate stroke or high-risk TIA at the cost of more severe bleeding. MATCH defines the danger of extending dual therapy indefinitely: over 18 months, life-threatening bleeding was approximately 2.6% with clopidogrel plus aspirin versus 1.3% with clopidogrel alone Ticagrelor Aspirin Aspirin 2020 · Clopidogrel Aspirin Acute 2018 · Clopidogrel Aspirin Acute 2013 · Aspirin clopidogrel compared 2004.

The contemporary asymptomatic-stenosis debate is being reshaped by CREST-2. CREST-2 enrolled patients with high-grade asymptomatic carotid stenosis into two parallel trials: intensive medical management alone compared with stenting plus intensive medical management, and intensive medical management alone compared with endarterectomy plus intensive medical management. The minimum high-grade asymptomatic stenosis threshold was 70%, across 155 centers in 5 countries, making it a direct test of whether modern revascularization adds benefit to contemporary intensive medical care CREST-2 medical management 2026.

The reported 4-year CREST-2 results complicate simple historical narratives. At 4 years, the primary composite outcome was lower with stenting plus intensive medical management than with intensive medical management alone, while the endarterectomy comparison did not show a statistically significant reduction versus medical management alone. Reported 4-year primary outcome rates were 6.0% in the stenting-trial medical-management group, 2.8% in the stenting group, and 5.3% in the endarterectomy-trial medical-management group. These findings should be interpreted in the context of trial design, patient selection, procedural quality, and evolving guideline updates CREST-2 medical management 2026 · CREST-2 protocol 2017.

European guidance illustrates the selective posture toward asymptomatic disease. The ESO guideline reserves endarterectomy for selected patients with 60–99% asymptomatic stenosis who are at increased stroke risk despite best medical therapy, while carotid stenting is framed mainly as an option for symptomatic patients younger than 70 years with 50–99% stenosis. This reinforces that plaque morphology, stenosis severity, age, symptoms, and procedural risk must be integrated rather than treated as independent indications European Stroke Organisation 2021.

A practical plaque conference should therefore ask five questions. Is the plaque symptomatic and ipsilateral to the event? Is the stenosis category confirmed by validated imaging? Are there plaque or patient features that modify risk? Has intensive medical therapy been initiated and tolerated? Can the center deliver the necessary 30-day stroke or death performance for the symptomatic or asymptomatic indication under consideration? This sequence keeps the discussion clinically anchored and avoids converting morphology into an unsupported mandate SVS 2022.

29.4Selecting patients for CEA, CAS, TCAR, or medical therapy transition

Patient selection begins with the question of whether intervention adds timely stroke prevention beyond medical therapy. For symptomatic 70–99% NASCET-method stenosis, the evidence for carotid endarterectomy is strong: NASCET reported an absolute reduction of approximately 17 percentage points in 2-year ipsilateral stroke. In a neurologically appropriate, non-disabling presentation, this evidence supports rapid movement from diagnosis to operation if perioperative risk is acceptable and the procedure can be performed within the high-benefit time window Endarterectomy symptomatic carotid 2004 · Randomised trial endarterectomy 1998 · NASCET · 1991.

The operative window is not a scheduling preference; it is part of the indication. Pooled NASCET/ECST data showed maximal benefit within 2 weeks of the qualifying event, and ESVS 2023 frames carotid endarterectomy as the preferred modality for symptomatic 70–99% stenosis within 14 days of the index neurological event. ESO similarly prioritizes treatment within 2 weeks after the qualifying retinal or cerebral ischemic event for symptomatic 50–99% stenosis. The vascular team should therefore treat diagnostic delay as a loss of therapeutic effect European Stroke Organisation 2021 · Endarterectomy symptomatic carotid 2004 · Randomised trial endarterectomy 1998 · NASCET · 1991.

Moderate symptomatic stenosis is a selection problem rather than a reflex operation. ESO recommends carotid endarterectomy for symptomatic 70–99% stenosis and suggests it for symptomatic 50–69% stenosis; NASCET found smaller benefit in 50–69% stenosis, with benefit concentrated in selected subgroups. Pooled NASCET/ECST analysis also reported sex-related differences, with an approximate NNT of 9 to prevent one ipsilateral stroke at 5 years in men compared with approximately 36 in women. These subgroup findings should inform individualized judgment without denying appropriately selected women with symptomatic high-grade stenosis access to beneficial surgery European Stroke Organisation 2021 · Endarterectomy symptomatic carotid 2004 · Randomised trial endarterectomy 1998 · NASCET · 1991.

Perioperative quality thresholds are decisive. ESVS 2023 frames an approximately 6% 30-day stroke or death cap as the operator-level threshold above which symptomatic carotid intervention loses net benefit, and an approximately 3% 30-day stroke or death cap for asymptomatic intervention. These figures are not audit decorations; they should determine whether a patient is offered local intervention, referred to a higher-performing service, or managed medically.

Asymptomatic intervention requires more stringent selection because benefit is modest, delayed, and dependent on procedural safety. ACAS and ACST-1 showed long-term stroke reduction after endarterectomy in patients with asymptomatic stenosis of 60% or greater under trial-era medical therapy, but contemporary best medical therapy lowers baseline risk. ACST-1 long-term follow-up reported 10-year stroke rates of approximately 10.8% after CEA and 16.9% in the deferred-CEA medical arm, emphasizing that any benefit must survive the initial procedural hazard and accrue over years Endarterectomy asymptomatic carotid 1995 · ACST-1 (10-year) 2010.

SVS 2022 provides a more intervention-supportive asymptomatic frame, describing carotid endarterectomy as indicated for stenosis of approximately 70% or greater by validated imaging when life expectancy and acceptable surgical risk criteria are satisfied. ESVS 2023 and ESO guidance are more selective, incorporating plaque morphology and increased stroke risk despite best medical therapy into the decision. The practical solution is not to memorize a single threshold but to make the indication reproducible: stenosis category, imaging validation, plaque-risk features, patient longevity, and center-specific 30-day outcomes should all be explicit SVS 2022 · European Stroke Organisation 2021.

CAS selection is narrower and more context-dependent than CEA selection in most guideline framings. The 2011 multisociety guideline established a broad CEA-preferred and CAS-reasonable framework in selected patients, while ESO frames carotid stenting mainly as an option for symptomatic patients younger than 70 years with 50–99% stenosis. Procedural technique belongs elsewhere, but selection at the bedside should still address age, symptom status, stenosis severity, anatomy, perioperative stroke risk, and whether the expected benefit equals or exceeds a well-performed endarterectomy or intensive medical therapy Editor's Choice European 2023 · SVS 2022 · European Stroke Organisation 2021 · ACC/AHA 2011.

Medical therapy transition is not a failure of procedural care; it is a defined endpoint for many patients. Patients with asymptomatic stenosis below a selected intervention threshold, limited life expectancy, unacceptable procedural risk, uncertain symptom attribution, inadequate imaging confirmation, or a competing stroke mechanism should be transitioned to intensive medical management with clear follow-up implications. AHA/ASA 2021 frames carotid intervention as one component of integrated secondary prevention beginning with antiplatelet therapy, statin initiation, blood-pressure control, and source-mechanism work-up SVS 2022.

Short-course dual antiplatelet therapy may bridge the acute minor-stroke or high-risk-TIA period, but the long-term plan should deliberately transition to single antiplatelet therapy when the acute window has passed. AHA/ASA 2021 frames short-course aspirin and clopidogrel after minor stroke or high-risk TIA with subsequent transition to single antiplatelet therapy, while MATCH demonstrates why prolonged DAPT is hazardous. In the operative candidate, antithrombotic plans must be coordinated with the procedural pathway rather than allowed to drift into indefinite dual therapy Aspirin clopidogrel compared 2004.

CREST-2 now occupies the center of asymptomatic decision-making. The trial design compared intensive medical management alone against stenting plus intensive medical management and against endarterectomy plus intensive medical management in high-grade asymptomatic stenosis. The 2026 results reported a lower 4-year primary composite outcome with stenting plus intensive medical management than with intensive medical management alone, while the endarterectomy comparison did not show a statistically significant reduction versus medical management alone. Selection discussions should therefore acknowledge that asymptomatic thresholds are actively evolving and should be revisited as guideline interpretations mature CREST-2 medical management 2026 · CREST-2 protocol 2017.

29.5Controversies, surveillance, and boundaries with intervention chapters

The central controversy in carotid disease is no longer whether symptomatic severe stenosis benefits from timely endarterectomy; it is how to preserve that benefit in modern systems while avoiding unnecessary intervention in lower-risk disease. NASCET, ECST, and pooled analyses support early intervention for appropriately selected symptomatic stenosis, but their value depends on accurate stenosis measurement, correct symptom attribution, rapid treatment, and acceptable perioperative outcomes. ECST also reminds surgeons that measurement methods differ: an ECST-method threshold of 80% is not numerically interchangeable with NASCET grading for the same lesion Endarterectomy symptomatic carotid 2004 · Randomised trial endarterectomy 1998 · NASCET · 1991.

Rapid-access pathways are a systems-level intervention with direct surgical consequences. EXPRESS reported a 90-day recurrent stroke rate of approximately 10.3% under a standard appointment pathway, falling to approximately 2.1% after introduction of urgent-access assessment and immediate treatment, with a hazard ratio near 0.20. The magnitude reflects pathway redesign rather than a single drug or procedure, but the implication for vascular services is clear: carotid diagnosis and secondary prevention must be organized around the first days and weeks after the event EXPRESS study 2007.

Guideline timing statements align with the pooled-trial signal. ESVS 2023 frames carotid endarterectomy as the preferred modality for symptomatic 70–99% stenosis within 14 days of the index neurological event, and ESO recommends endarterectomy for symptomatic 70–99% stenosis, suggests it for symptomatic 50–69% stenosis, and prioritizes treatment within 2 weeks for symptomatic 50–99% stenosis after a qualifying retinal or cerebral ischemic event. These recommendations belong in the diagnostic and triage pathway, not only in the operating room consent discussion European Stroke Organisation 2021.

Asymptomatic surveillance is controversial because stenosis progression, plaque morphology, procedural risk, medical-therapy intensity, and life expectancy all influence whether a future intervention will be reasonable. The chapter-level principle is that surveillance should be tied to an actionable threshold: repeat imaging is valuable when it can identify progression, confirm stability, or trigger reconsideration of intervention under a guideline-supported framework. Surveillance without a management consequence risks converting incidental plaque into perpetual anxiety SVS 2022.

The operator-risk boundary is one of the most important safeguards in asymptomatic disease. ESVS 2023 frames an approximately 3% 30-day stroke or death cap for asymptomatic carotid intervention, while symptomatic intervention requires an approximately 6% cap. These thresholds should be discussed transparently in morbidity review and service planning because they define whether local intervention reproduces the conditions under which benefit was observed.

The AHA/ASA secondary-prevention lineage is relevant because carotid intervention is embedded in broader stroke prevention. The 2014 AHA/ASA secondary-prevention guideline has been superseded by the 2021 update, and current patient-facing recommendations should therefore rest on the 2021 framework. That framework emphasizes source-mechanism work-up, antiplatelet therapy, statin therapy, blood-pressure control, and individualized risk-factor management before, during, and after any carotid procedure Guidelines Prevention Stroke 2014.

Boundaries with intervention chapters should be explicit. This chapter defines who is at risk, how stenosis and plaque are evaluated, how medical therapy changes natural history, and how patient selection is framed. Technical choices such as exposure, shunting, patching, embolic protection, access strategy, and device-specific execution belong in procedural chapters. The clinical interface is the handoff: a patient should arrive at the intervention chapter with symptom status, timing, stenosis method, confirmatory imaging, mechanism attribution, antithrombotic plan, statin plan, blood-pressure strategy, and perioperative-risk justification already defined Editor's Choice European 2023 · SVS 2022 · ACC/AHA 2011.

Follow-up after a medical or procedural decision should track the risks that created the indication. For symptomatic disease, the key early question is whether the first-90-day recurrence window has been addressed with urgent secondary prevention and, when indicated, timely intervention. For asymptomatic disease, follow-up should reassess stenosis category, plaque-risk features when available, medical-therapy adherence, blood-pressure and lipid management, smoking status, life expectancy, and whether procedural risk remains acceptable. The goal is not repeated imaging for its own sake, but preservation of a coherent stroke-prevention plan SVS 2022 · One-Year Risk Stroke 2016 · EXPRESS study 2007.

The mature vascular approach is to separate durable evidence from moving targets. Timely CEA for symptomatic severe stenosis is durable evidence. Short-course dual antiplatelet therapy after selected minor stroke or high-risk TIA is a defined acute strategy, not a permanent regimen. High-intensity statin therapy and blood-pressure control are foundational. Asymptomatic intervention thresholds remain the moving target, especially as CREST-2 and contemporary medical therapy reshape baseline risk and comparative benefit CREST-2 medical management 2026 · Clopidogrel Aspirin Acute 2018 · Clopidogrel Aspirin Acute 2013 · High-Dose Atorvastatin after 2006 · Aspirin clopidogrel compared 2004 · Endarterectomy symptomatic carotid 2004 · NASCET · 1991.