Prevalence of Nonstenotic Carotid Plaque in Stroke Due to Atrial Fibrillation Compared to Embolic Stroke of Undetermined Source.

Background: Embolic stroke of undetermined source (ESUS) accounts for about 20% of strokes. Nonstenotic cervical arterial plaque may be a mechanism of stroke in a subset of these patients. Methods: A cohort of consecutive patients with ischemic stroke was retrospectively identified from a stroke registry. Patients with unilateral anterior circulation embolic stroke due to atrial fibrillation (AF) or consistent with ESUS who underwent computed tomographic neck angiography were included. The prespecified primary outcome was a comparison of the prevalence of carotid plaque greater than or equal to 3 mm thickness ipsilateral versus contralateral to the infarct side. Results: Of 772 screened patients, 96 patients with ESUS and 99 patients with AF were included. Plaque greater than or equal to 3 mm was more frequently ipsilateral than contralateral to the infarct in patients with ESUS (41% versus 29%, P = .03), and plaque thickness was greater ipsilateral compared to contralateral (median 2.5 versus 2.2 mm, P = .02). No significant differences in plaque characteristics ipsilateral compared to contralateral were found in patients with AF. The prevalence of ipsilateral versus contralateral plaque was greater in ESUS patients less than or equal to 65 years old (48% versus 19%, P < .01), but no different in patients greater than 65 years old (35% versus 39%, P = .57). Conclusions: Nonstenotic cervical carotid plaque is more common ipislateral to the infarction in patients with ESUS, but not in patients with AF, supporting an underlying atheroembolic mechanism in a subset of ESUS patients. This association might be greater in younger ESUS patients.