Vulnerable plaque of the petrous internal carotid artery in embolic stroke of undetermined source

Abstract Background and purpose The association between nonstenotic plaque at the petrous internal carotid artery (ICA) and embolic stroke of undetermined source (ESUS) remains unknown. We aimed to test the hypothesis that the presence of a larger build‐up of petrous plaque is more prevalent in the ipsilateral versus the contralateral side among ESUS patients without plaque in the intracranial and proximal ICA. Methods From a total of 243 patients with ESUS and 160 patients with small‐vessel disease (SVD) without proximal ICA plaque, we enrolled 88 ESUS and 103 SVD patients without ipsilateral nonstenotic intracranial and proximal ICA plaque in the present study. Targeting the petrous segment of the ICA on two sides, plaque burden including plaque thickness, lumen area, vessel area, wall area, and percentage of luminal stenosis, and composition features (presence/absence of the ruptured fibrous cap, ulcer plaque, thrombus, discontinuity of plaque surface [DPS], intraplaque hemorrhage and complicated plaque) were assessed by high‐resolution magnetic resonance imaging. Results We found a higher prevalence of petrous plaque thickness ≥3.5 mm ipsilateral versus contralateral to the stroke (25/88 [28.4%] vs. 12/88 [13.6%], odds ratio [OR] 3.60, 95% confidence interval [CI] 1.34–9.70), but this imbalance was not seen in SVD. In patients with plaque thickness ≥3.5 mm, the presence of DPS (OR 4.05, 95% CI 1.11–14.78) and complicated plaque (OR 5.00, 95% CI 1.10–22.82) was more closely related to an index ESUS, a finding that was not evident in the subgroup with petrous plaque <3.5 mm ( p for interaction = 0.027). Conclusions The present study provided the first evidence supporting a potential etiological role of vulnerable petrous plaque in ESUS.