Abstract WMP84: Symptomatic Intracranial Atherosclerotic Plaques: Different Morphological Features In The Anterior Versus Posterior Circulation

Introduction: We compared the morphology of intracranial atherosclerotic plaques in the anterior versus posterior circulation, using three-dimensional rotational angiography (3DRA). Methods: We prospectively recruited adult patients with acute ischemic stroke or transient ischemic attack attributed to high-grade (60-99%), atherosclerotic intracranial stenosis as confirmed by 3DRA. We assessed the plaque morphology in 3DRA, including the percentage of luminal stenosis, smooth/irregular/ulcerative plaque surface contour, plaque thickness, length, eccentricity, upstream plaque shoulder angulation, longitudinal distribution of the maximal stenosis, and adjoining branch atheromatous disease (BAD). We compared characteristics of patients with middle cerebral artery-M1 (MCA-M1) and basilar artery (BA) plaques, and the plaque morphology in the two subgroups. Results: Overall, 164 and 17 patients respectively with MCA-M1 and BA plaques were analyzed, with similar age (medians 60 versus 62 years), sex (male 64.6 versus 52.9%) and history of common vascular risk factors. The percentage of luminal stenosis (medians 77 versus 81%), proportion of smooth/irregular/ulcerative plaque surface contour, upstream plaque shoulder angulation (32.1 versus 25.8 °), longitudinal distribution of the maximal stenosis, and presence of adjoining BAD (56.7 versus 64.7%) were similar between MCA-M1 and BA plaques. However, BA plaques were thicker (1.5 versus 1.3mm; p=0.03) and longer (16.4 versus 8.4mm; p<0.001), but less likely eccentric (70.6 versus 88.4%; p=0.039). Conclusions: There were differences in the morphology of symptomatic atherosclerotic plaques in anterior and posterior circulations, independent of demographics and common vascular risk factors. Different artery geometry and the hemodynamics may underlie such differences.