Histological Assessment of 526 Symptomatic Carotid Plaques in Relation to the Nature and Timing of Ischemic Symptoms

Abstract

Background— Atherosclerotic plaque at the carotid bifurcation is often associated with transient ischemic attack (TIA) and ischemic stroke, but the mechanisms are not completely understood. Previous histological studies have been too small or insufficiently detailed to reliably determine the temporal course of features of plaque instability or to stratify analyses by the nature of presenting symptoms. Methods and Results— We performed the largest-ever histological study of symptomatic carotid plaques from consecutive patients (n=526) undergoing endarterectomy and related detailed reproducible histological assessments to the nature and timing of presenting symptoms. There was a high prevalence of many features of coronary-type plaque instability. Dense plaque inflammation (especially infiltration with macrophages) was the feature most strongly associated with both cap rupture (odds ratio 3.39, 95% confidence interval 2.31 to 4.98, P<0.001) and time since stroke (P=0.001). Strong negative associations with ...