Risk of ipsilateral and recurrent stroke over 5-years in patients with non-stenotic carotid disease: A retrospective imaging-based population level study from Manitoba

Abstract Background Symptomatic Non-stenotic Carotid (SyNC) disease is an increasingly recognized etiology in ischemic stroke, particularly in the presence of certain high-risk plaque features. The aim of this population level clinical-imaging study was to examine the risk of ipsilateral and recurrent stroke in SyNC with 5-year follow-up. Methodology All patients with an index stroke/TIA in calendar year 2019 were identified, and baseline & follow-up imaging were analyzed through December 2023 to assess recurrent stroke. CT Angiograms were assessed for plaque features such as degree of stenosis, plaque thickness, calcification, plaque irregularity, ulceration, positive rim sign, and focal vessel caliber increase. Parenchymal imaging was assessed for infarct presence on same side as carotid disease (concordant stroke). Analysis was performed at the patient and carotid level using unadjusted and adjusted logistic regression analysis. Sensitivity analysis excluding patients with competing stroke etiologies was also completed. Results Of the total 1249 patients with stroke, 658 patients with available neck imaging and ≤50% stenosis were included. Of these, 153 (23.5%) had concordant stroke and 76 (11.6%) had recurrent stroke. In adjusted analysis, there was significantly increased odds of concordant stroke at index presentation with stenosis grade [aOR 3.56, 95% CI 2.99 – 4.25] and plaque thickness [aOR 1.19, 95% CI 1.03 – 1.38]. Similarly, adjusted analysis showed significant increase in odds of recurrent concordant stroke with degree of stenosis [aOR 2.39, 95% CI 1.94 – 2.95], plaque thickness [aOR 1.32, 95% CI 1.05 – 1.67], and plaque ulceration [aOR 3.86, 95% CI 1.31 – 11.35]. Results remained consistent after sensitivity analysis. Conclusion This retrospective analysis of the population level clinical-imaging study shows that plaque thickness, degree of stenosis and plaque ulceration are associated with increased risk of index and recurrent ischemic strokes. More prospective data is needed to validate these findings.