Features of Unstable Carotid Plaque During and After the Hyperacute Period Following TIA/Stroke

Background: The aim was to test the hypothesis that histologically unstable carotid plaque features were more prevalent in patients undergoing carotid endarterectonny (CEA) in the acute period after onset of symptoms and that the plaque would assume more stable histological characteristics as the delay from the most recent event increased. Methods: Seven histological features of plaque instability (haemorrhage, large lipid core, chronic plaque inflammation, chronic cap inflammation, marked vascularity, cap rupture and many foam cells) were independently quantified and then correlated with recency of symptoms in patients undergoing CEA. Results: In patients undergoing CEA <= 14 days of their last event, 87/119 (73%) exhibited >= 5/7 unstable histological plaque features, compared with 22/40 (55%) of patients undergoing delayed surgery (P = 0.048). As expected, there was a sustained decline in the prevalence of unstable plaque features in 61 patients undergoing surgery between days 7-28. However, there was then a marked increase in the prevalence of plaque haemorrhage (59% up to 65%), large lipid core (41% up to 78%), chronic plaque inflammation (71% up to 91%), cap rupture (35% up to 39%), many foam cells (24% up to 43%) and marked vascularity (71% up to 91%) in 23 patients undergoing CEA after 29 days had elapsed. Conclusion: Patients undergoing surgery <= 14 days had a significantly higher overall burden of high risk plaque features compared with those undergoing delayed CEA. However, the secondary upsurge across a range of unstable plaque features in patients undergoing CEA after >= 29 days had elapsed suggests that the relationship between recency of symptoms and plaque histology is more complex than had been anticipated in previous studies.. (C) 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved. Article history: Received 18 September 2012, Accepted 19 November 2012, Available online 25 December 2012