Derivation of a CT Angiography-Based Arch Atherosclerosis Grading in Cryptogenic Ischemic Stroke

BACKGROUND AND OBJECTIVES: We aimed to develop a novel computed tomography angiography (CTA)-based grading system to quantify the severity of aortic arch disease and compare the detection of aortic arch atherosclerosis (AAAthero) on routinely acquired arch-to-vertex CTA against transesophageal echocardiogram (TEE) among patients with cryptogenic ischemic stroke. METHODS: A systematic literature review was conducted to develop a computed tomography (CT)-based AAAthero grading system. CTA was compared against TEE for detecting AAAthero. The severity of arch atherosclerosis was scored based on a 5-point grading system. Patients with cryptogenic stroke who underwent both CTA and TEE were included in the derivation cohort to assess the sensitivity and specificity of CTA compared to TEE. The CT-based grading system for aortic plaques was then applied to an independent cohort of patients with cryptogenic stroke. RESULTS: Three studies were identified in a systematic review, and 141 patients were included in the derivation cohort. AAAthero was detected in 29 patients (20.6%) and 28 patients (19.9%) on TEE and CTA, respectively. The sensitivity of CTA to detect any atherosclerosis was 76%, which increased to 100% to detect moderate to severe disease. The specificity was 95% for any atherosclerosis and 100% for moderate to severe arch disease. Seven patients with AAAthero on TEE had normal CTA, but mild arch disease. Meanwhile, six patients with CTA and negative TEE had plaques on the arch's transverse segment. CONCLUSIONS: Routinely acquired arch-to-vertex CTA provides an accurate, noninvasive alternative to TEE for detecting AAAthero, especially in clinically relevant moderate to severe arch disease.