Prognostic value of plaque burden on computed tomography angiography in patients with symptomatic carotid artery disease

INTRODUCTION: Patients with symptomatic carotid stenosis are at increased risk for recurrent ischaemic stroke. Plaque burden on MRI has been shown to independently predict (recurrent) ischaemic stroke. However, CT is usually preferred in acute stroke patients due to its availability and rapid scan time. We examined whether carotid plaque burden on CTA can also independently predict (recurrent) ipsilateral ischaemic cerebrovascular symptoms in patients with symptomatic carotid stenosis. PATIENTS AND METHODS: In the Plaque At RISK (PARISK) study, recently symptomatic patients with < 70% carotid stenosis underwent a carotid CTA at baseline. Plaque burden was quantified as total plaque volume (μL) of the ipsilateral carotid artery using semiautomated segmentation. Cox proportional hazards models were used to assess whether plaque burden on CTA was associated with recurrent ipsilateral ischaemic events. Plaque burden was added to an existing prediction model (ECST score) to determine additional predictive value. RESULTS: During a median follow-up of 5.1 [IQR: 3.4-5.7] years, 26 of 199 patients experienced a (recurrent) ipsilateral TIA or stroke. A larger plaque burden increased the risk of recurrent ipsilateral stroke or TIA (HR = 1.07 [95% CI, 1.00-1.14] per 100 μL increase; P = .04). Performance of the ECST score increased from a C-statistic of 0.65-0.70 upon addition of plaque burden. DISCUSSION: The association between CTA-based plaque burden and recurrent ischaemic events aligns with previous MRI-based findings, suggesting that CTA can provide predictive value when MRI is unavailable. CONCLUSIONS: Plaque burden on CTA is an independent predictor for recurrent ipsilateral stroke or TIA in symptomatic patients with a < 70% carotid stenosis.