Unstable carotid plaque characteristics increase between 2010-2021 in carotid endarterectomy patients

Background: Over the past decades, carotid plaque characteristics have been studied in association with previous symptoms and future cardiovascular events. We showed that destabilizing atherosclerotic plaque characteristics in carotid atherectomy patients between 2002 -2011 were decreasing. Time-dependent changes in plaque composition in the last decade, however, have not been studied. In this study, we investigate carotid plaque characteristics in carotid endarterectomy patients over the last decade. Methods: Atherosclerotic plaques from 1,362 carotid endarterectomy patients included in the Athero-Express biobank between 2010 and 2021 were analyzed to examine time dependent changes in histological plaque characteristics in intervals of 2 years. These results were compared with our previous time dependent plaque composition data between 2002-2011. Results: In contrast to the period 2002-2011 where vulnerable plaque characteristics were decreasing, the period 2010-2021 showed significant increase in vulnerable plaque characteristics: large lipid cores, intraplaque hemorrhage, macrophages, and calcification. When adjusted for confounders related to these plaque characteristics, such as time to operation and pre-operative symptoms, the adjusted odds ratios per 2 years increase in time were 1,177 (95% confidence interval, 1,070-1,293; p<0,001) for calcification, 1,352 (95% confidence interval, 1,229-1,487; p<0,000) for intraplaque hemorrhage, 1,277 (95% confidence interval, 1,159-1,407; p<0,000) for plaques consisting of >40% of fat and 1,388 (95% confidence interval, 1,262-1,528; p<0,000) for macrophages. Conclusion: Our study shows an increase in plaque characteristics associated with plaque vulnerability in 2010-2021 despite an overall decrease in cardiovascular mortality in Western Europe. Keywords: Plaque vulnerability, Atherosclerosis, Carotid endarterectomy, Time dependent changes