Magnetic Resonance Imaging Plaque Hemorrhage for Risk Stratification in Carotid Artery Disease With Moderate Risk
Akram A Hosseini1, Richard J Simpson1, Nishath Altaf1
1From the Radiological Sciences, Division of Clinical Neuroscience (A.A.H., R.J.S., N.A., D.P.A.); Stroke Trials Unit, Division of Clinical Neuroscience (P.M.B.), University of Nottingham, United Kingdom; and Department of Vascular Surgery, Nottingham University Hospital NHS Trust, United Kingdom (R.J.S., N.A., S.T.M.).
Background And Purpose:
Magnetic resonance imaging (MRI)-defined carotid plaque hemorrhage (MRIPH) can predict recurrent cerebrovascular ischemic events in severe symptomatic carotid stenosis. It is less clear whether MRIPH can improve risk stratification despite optimized medical secondary prevention in those with moderate risk.
Methods:
One-hundred fifty-one symptomatic patients with 30% to 99% carotid artery stenosis (median age: 77, 60.5% men) clinically deemed to not benefit from endarterectomy were prospectively recruited to undergo MRI and clinical follow-up (mean, 22 months). The clinical carotid artery risk score could be evaluated in 88 patients. MRIPH+ve was defined as plaque intensity >150% that of adjacent muscle. Survival analyses were performed with recurrent infarction (stroke or diffusion-positive cerebral ischemia) as the main end point.
Results:
Fifty-five participants showed MRIPH+ve; 47 had low, 36 intermediate, and 5 high carotid artery risk scores. Cox regression showed MRIPH as a strong predictor of future infarction (hazard ratio, 5.2; 95% confidence interval, 1.64-16.34; P=0.005, corrected for degree of stenosis), also in the subgroup with 50% to 69% stenosis (hazard ratio, 4.1; 95% confidence interval, 1-16.8; P=0.049). The absolute risk of future infarction was 31.7% at 3 years in MRIPH+ve versus 1.8% in patients without (P<0.002). MRIPH increased cumulative risk difference of future infarction by 47.1% at 3 years in those with intermediate carotid artery risk score (P=0.004).
Conclusions:
The study confirms MRIPH to be a powerful risk marker in symptomatic carotid stenosis with added value over current risk scores. For patients undergoing current secondary prevention medication with clinically uncertain benefit from recanalization, that is, those with moderate degree stenosis and intermediate carotid artery risk scores, MRIPH offers additional risk stratification.
Insights
Magnetic resonance imaging-defined carotid plaque hemorrhage (MRIPH) strongly predicts future strokes in symptomatic carotid stenosis patients. MRIPH offers crucial additional risk stratification for intermediate-risk individuals on secondary prevention.
Area of Science:
- Neurology
- Cardiovascular Medicine
- Radiology
Background:
- Carotid plaque hemorrhage (MRIPH) identified via MRI is a known predictor of recurrent ischemic events in severe symptomatic carotid stenosis.
- Its utility in refining risk stratification for patients with moderate stenosis undergoing optimized medical secondary prevention remains less understood.
Purpose of the Study:
- To investigate the predictive value of MRIPH for recurrent cerebrovascular ischemic events in patients with moderate to severe symptomatic carotid stenosis.
- To determine if MRIPH improves risk stratification beyond established clinical risk scores in this population.
Main Methods:
- Prospective recruitment of 151 symptomatic patients (30%-99% carotid artery stenosis) not candidates for endarterectomy.
- MRI assessment for MRIPH and clinical follow-up for recurrent infarction over a mean of 22 months.
- Survival analyses, including Cox regression, were performed to assess MRIPH as a predictor of future infarction.
Main Results:
- Fifty-five participants (36.4%) showed MRIPH. MRIPH was a significant predictor of future infarction (HR, 5.2; P=0.005), even in moderate stenosis subgroups (50%-69% stenosis; HR, 4.1; P=0.049).
- The 3-year risk of infarction was substantially higher in MRIPH-positive patients (31.7%) compared to MRIPH-negative patients (1.8%; P<0.002).
- MRIPH significantly increased the cumulative risk difference for future infarction by 47.1% at 3 years in patients with intermediate carotid artery risk scores (P=0.004).
Conclusions:
- MRIPH is a powerful risk marker in symptomatic carotid stenosis, providing added value beyond current risk scores.
- For patients with moderate stenosis and intermediate risk scores on secondary prevention, MRIPH offers essential additional risk stratification.
- This imaging biomarker can aid in identifying high-risk individuals who may benefit from closer monitoring or more aggressive management strategies.
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