Carotid artery risk score

David Goldemund M.D.
Updated on 03/11/2023, published on 30/05/2023
  • Carotid Artery Risk (CAR) score estimates the 5-year ipsilateral stroke rate in recently symptomatic patients with carotid stenosis of ≥ 50% treated with optimized medical therapy (OMT)
  • the algorithm incorporates the effects of modern medical management
  • the calculator was used to determine patient eligibility for the ECST-2 trial
    • ECST-2 trial evaluated the optimal treatment for patients with symptomatic or asymptomatic moderate-to-severe carotid stenosis, who are at low-to-intermediate risk of recurrent stroke
    • the trial compared the risks and benefits of OMT alone versus OMT + immediate carotid surgery (or stenting)
    • patients with symptomatic stenosis or stenosis that has not caused symptoms for ≥ 180 days were automatically eligible for the ECST-2 trial
  • the score serves as a guide; it should not substitute for the judgment of experienced clinicians, who must consider all relevant information about the individual patient
  • the color-coded risk tables serve as an alternative to the computer model
  • these tables predict the 5-year risk of ipsilateral ischemic stroke in patients with recently symptomatic carotid stenosis who are on medical treatment based on data derived from the ECST model  (Rothwell, 1999)
The 5-year risk of stroke in patients with carotid stenosis (model derived from ECST trial)
  • nearly 430 patients with symptomatic and asymptomatic atherosclerotic carotid stenosis of ≥50% and a Carotid Artery Risk (CAR) score <20% were randomized to optimized medical therapy (OMT) alone or OMT plus revascularization via carotid endarterectomy (CEA) or carotid artery stenting (CAS)
  • preliminary results suggest that adding carotid revascularization to OMT does not appear to offer clinical benefit in patients with significant carotid stenosis who have a low-to-intermediate 5-year risk of stroke
    • no significant difference exists between the treatment groups at 2 years regarding the rate of a composite endpoint, as well as the occurrence of any stroke, myocardial infarction, and periprocedural death

Explanation of items in the CAR score

  • degree of stenosis
    • measured by NASCET criteria (50-99%;  no evidence of benefit in patients with <50% stenosis)
    • if reported by ultrasound as a range of values, use the middle of the range (e.g., for a report saying stenosis 50-59%, enter 55)
  • near occlusion – severe (subtotal) stenosis associated with the collapse of the carotid artery distal to the stenosis (string sign)
  • time in days since the last event
    • risk predictions will not correctly assess the patients who have experienced multiple recurrent events in recent months
  • definition of events
    • major stroke = a non-disabling stroke with residual signs present or expected to persist > 7 days
    • minor stroke = a stroke with signs and symptoms lasting or expected to last between 24 hours and 7 days
    • TIA = symptoms lasting < 24 hours (old definiton)
    • multiple TIAs
    • monocular symptoms = amaurosis fugax (TIA) or retinal infarction (CRAO)
  • plaque ulceration
    • clear evidence of ulcerated plaque on noninvasive imaging
    • irregular and ulcerated plaques have been shown to correlate highly with with lipid-rich, unstable, or ruptured plaques on histology ⇒ patients with evidence of lipid-rich or unstable/ruptured plaque on noninvasive imaging could, therefore, be recorded as having irregular or ulcerated plaque
  • MI – history of myocardial infarction
  • PVD – history of peripheral vascular disease (also known as PAD)

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Carotid artery risk score
link: https://www.stroke-manual.com/carotid-artery-risk-score/