Atherosclerosis: pathologic process thatcauses disease of the arteries.

Most common cause of in situ local diseasewithin the supraaortic arteries and intracranialarteries.

Chronic disease:childhood: fatty streaksfibrous plaquesfibrous capsadvanced atheromatous lesions

Multiple pathogenic factors:endothelial dysfunctioninflammatory and immunologic factorsplaque rupturetraditional risk factors

PATHOPHYSIOLOGY

In-situ thromboembolism:local thrombosis, embolism (multiple cortical infarcts)

Progression of luminal stenosis:hemodynamic insufficiency (watershed infarct)

Branch atheromatous disease:small vessel occlusion (single deep infarct)

PATHOPHYSIOLOGY: STROKE MECHANISMS EPIDEMIOLOGYCommon cause of ischemic stroke

50% in Asia, most common worldwide?Whites: 5 - 10%. Higher in hispanics (x4), blacks (x5), Asians (x6)Underdiagnosis of non-stenosing plaques

Genetic susceptibilityVs.

Differences in lifestyle and risk factors

HypertensionDyslipidemia *severe stenosisDiabetes *carotidAge *basilarMetabolic syndromeSedentarismSmoking

*MCA: women, blacks

RISK FACTORSRisk factors more prevalent than in other stroke subtypes Noninvasive neurovascular imaging

CTA, MRA, TCDBetter NPV than PPVLimitations:

occlusion vs. pseudo-occlusionoverestimate severity of stenosis

Catheter angiography (1% complications)Advantages:

accurate measurement of the degree of stenosisdifferentiation of occlusion vs. pseudo-occlusionassessment of collateral flow patterns

Indications:The added information is unlikely to alter management. I ti t lt ti ti l i di ti liti

DIAGNOSIS

Is thisaterosclerosis?

High-resolution vessel wall imagingIs this

aterosclerosis?

Clinicalpresentation

Less common conditions

Dissection: less frequent than extracranial dissections. String sign, tapered/flame-shaped occlusion, intimal flap, dissecting aneurysm, distal pouchIntramural hematoma in fat-saturated MRI

Primary angiitis CNS: rarePresentation: insidious, headache, cognitive impairment, and multiple infarcts in different

vascular territories. ”String of beads" in smaller distal intracranial vessels.

Reversible cerebral vasoconstriction syndrome: Thunderclap headache

Fibromuscular displasia: most frequently involves the renal and internal carotid and vertebral arteries.

Moyamoya: bilateral stenoses affecting the distal internal carotid arteries and prominent collateralvessels.

DIFFERENTIAL DIAGNOSISHigh risk of stroke, especially in symptomatic cases (up to 25% anual risk in WASID)

Lower with intensive medical therapy (SAMMPRIS 12%)

Subgroups with high risk of stroke:Degree stenosis: severe (≥70%) HR 2Hypoperfusion (“hemodynamic stenosis”) Recent ischemic symptomsPresentation with stroke (vs. TIA)Old infarct in the territory of the stenosisWomenAbsence of statin at trial entry

PROGNOSIS

TREATMENTMaximal medical therapy: association between good control of risk factors and lower risk of events

Antiplatelets: dual antiplatelet for 3 weeks – 3 months (CHANCE subgroup analysis)

ticagrelor in clopidogrel resistants?Intensive control of vascular risk factors:

Antihypertensive agents: the majority of patients benefit from SBP <140 (WASID, SAMMPRISS)

Statins: target LDL-C <70 mg/dLLifestyle modification: exercise

smoking cessationweight reductionhealthy diet: mediterranean diet (Estruch et al NEJM 2013)

Interventions:EC-IC bypassStenting

SAMMPRISVISSIT

y

Atherosclerotic stenosis of the major intracranial arteries is a commoncause of ischemic stroke, especially in blacks, Asians, and Hispanics

Diagnosis usually made with noninvasive imaging

Differential diagnosis includes other less common types of intracranialvasculopathies

The anual risk of stroke is high, especially in patients with severe stenosis

Despite this, the primary treatment is based in MAXIMAL medical therapy that includes antiplatelet and antihypertensive agents, statins, and lifestyle modifications

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