Carotid Artery Stenosis

Posted by e-Medical PPT Tuesday, November 20, 2012
Internal Carotid Artery Stenosis is responsible for 30% of ischemic strokes
• 4-8% of 50-79 year old patients have ICA stenosis >50%
• ICA stenosis causes mostly (90%) embolic strokes, rarely failure of perfusion

Carotid Artery Stenosis
• Asymptomatic
• Symptomatic

Natural History
Short term (2-3 years)1-3% incidence of unheralded ipsilateral CVA
• Approximate event rate of <1%/year for <50% stenosis
• Approximate event rate of 1%/year for >50% stenosis

Asymptomatic Carotid Atherosclerosis Study
Limitations of ACAS
Absolute stroke risk reduction of 1.2%/year
– Eg pt with 3%/year stroke risk now with 1.8%/year stroke risk
– Risk of cardioembolic, lacunar CVA NOT reduced
• Perioperative complication rate 2.3%; death 0.1%
– Good risks; 25 pts screened for every 1 enrolled
– Other studies show 4.6-5.1% incidence of perioperative
stroke/death in aysmptomatic ICA with CEA
– If 5% event rate applied, results of ACAS are nullified
• CEA not beneficial for women with ICA 60-99%!
• No incremental benefit for increasing stenoses
– 60-69% stenosis had HIGHER benefit than 80-89%!

Asymptomatic Carotid Surgery Trial
Largest prospective study to date, most recent
(May 2004)
• 3120 patients, 5 year followup; 10 year period
• ICA >60% stenosis (ultrasound)
• Immediate CEA vs. Deferred CEA (+ ‘usual
therapy)
• 5 year stroke risk – 6.4% CEA; 11.8% medical
– Men and women, all age groups, all stenosis subsets
– 3% perioperative event rate

Screening Methods
Carotid duplex US
– 85% sensitivity/specificity for 70-99% vs <70%
• Digital Subtraction Angiography
– Clinical periprocedure CVA rate of 1%
– Gold standard
• MRA (Elliptic Centric Contrast Enhanced MRA)
– 95% sensitivity/ 90% specificity for 70-99% vs <70%
• Spiral CTA
– 74-100% sensitivity/ 83-100% specificity for 70-99%
vs <70%
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