Risk of intracranial hemorrhage after carotid artery stenting versus endarterectomy: a population-based study

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Intracranial hemorrhage (ICH) associated with cerebral hyperperfusion syndrome is a rare but major complication of carotid artery revascularization. The objective of this study was to compare the rate of ICH after carotid artery stenting (CAS) with that after endarterectomy (CEA).


The authors performed a retrospective population-based cohort study of patients who underwent carotid artery revascularization in the province of Ontario, Canada, between 2002 and 2015. The primary outcome was the rate of ICH that occurred within 90 days after carotid artery intervention among patients who underwent CAS versus that of those who underwent CEA. The authors used inverse probability of treatment weighting and propensity scores to account for selection bias. In sensitivity analyses, patients who had postprocedure ischemic stroke were excluded, and the following subgroups were examined: patients with symptomatic and asymptomatic carotid artery stenosis, patients treated between 2010 and 2015, and patients aged ≥ 66 years (to account for antiplatelet and anticoagulant use).


A total of 16,688 patients underwent carotid artery revascularization (14% CAS, 86% CEA). Patients with more comorbid illnesses, symptomatic carotid artery stenosis, or cardiac disease and those who were taking antiplatelet agents or warfarin before surgery were more likely to undergo CAS. Among the overall cohort, 80 (0.48%) patients developed ICH within 90 days (0.85% after CAS, 0.42% after CEA). The 180-day mortality rate after ICH in the overall cohort was 2.7%, whereas the 180-day mortality rate among patients who suffered ICH was 42.5% (40% for CAS-treated patients, 43.3% for CEA-treated patients). In the adjusted analysis, patients who underwent CAS were significantly more likely to have ICH than those who underwent CEA (adjusted OR 1.77; 95% CI 1.32–2.36; p < 0.001). These results were consistent after excluding patients who developed postprocedure ischemic stroke (adjusted OR 1.90; 95% CI 1.41–2.56) and consistent among symptomatic (adjusted OR 1.74; 95% CI 1.16–2.63) and asymptomatic (adjusted OR 1.75; 95% CI 1.16–2.63) patients with carotid artery stenosis, among patients treated between 2010 and 2015 (adjusted OR 2.21; 95% CI 1.45–3.38), and among the subgroup of patients aged ≥ 66 years (adjusted OR 1.53; 95% CI 1.05–2.24) after adjusting for medication use.


CAS is associated with a rare but higher risk of ICH relative to CEA. Future research is needed to devise strategies that minimize the risk of this serious complication after carotid artery revascularization.

ABBREVIATIONS CAS = carotid artery stenting; CEA = carotid endarterectomy; ICD-10-CM = International Classification of Diseases, 10th Revision, Clinical Modification; ICH = intracranial hemorrhage; IPTW = inverse probability of treatment weighting.

Article Information

Correspondence Mohammed Al-Omran: St. Michael’s Hospital, Toronto, ON, Canada. alomranm@smh.ca.

INCLUDE WHEN CITING Published online February 2, 2018; DOI: 10.3171/2017.8.JNS171142.

M.A.H. and A.S.A. contributed equally to this work.

Disclosures Dr. Bhatt reports that he is on the advisory board of Cardax, Elsevier Practice Update Cardiology, Medscape Cardiology, and Regado Biosciences; is on the board of directors for the Boston VA Research Institute and Society of Cardiovascular Patient Care; is a chair on the American Heart Association Quality Oversight Committee; is on the Data Monitoring Committee for the Cleveland Clinic, Duke Clinical Research Institute, Harvard Clinical Research Institute, Mayo Clinic, and Population Health Research Institute; has received honoraria from the American College of Cardiology (senior associate editor, Clinical Trials and News, ACC.org), Belvoir Publications (editor-in-chief, Harvard Heart Letter), Duke Clinical Research Institute (clinical trial steering committees), Harvard Clinical Research Institute (clinical trial steering committee), HMP Communications (editor-in-chief, Journal of Invasive Cardiology), Journal of the American College of Cardiology (guest editor and associate editor), Population Health Research Institute (clinical trial steering committee), Slack Publications (chief medical editor, Cardiology Today’s Intervention), Society of Cardiovascular Patient Care (secretary/treasurer), and WebMD (CME steering committees); is deputy editor of Clinical Cardiology; is a chair on the NCDR-ACTION Registry Steering Committee and the VA CART Research and Publications Committee; has received research funding from Amarin, Amgen, AstraZeneca, Bristol-Myers Squibb, Chiesi, Eisai, Ethicon, Forest Laboratories, Ironwood, Ischemix, Lilly, Medtronic, Pfizer, Roche, Sanofi Aventis, and The Medicines Company; has received royalties from Elsevier (editor, Cardiovascular Intervention: A Companion to Braunwald’s Heart Disease); is site coinvestigator for Biotronik, Boston Scientific, and St. Jude Medical; is a trustee for the American College of Cardiology; and has performed unfunded research for FlowCo, Merck, PLx Pharma, and Takeda. This study was funded by the Physicians’ Services, Inc., Foundation and the King Saud University–Li Ka Shing Collaborative Research Program. This study was supported also by the Institute for Clinical Evaluative Sciences (ICES), which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). Dr. Saposnik is supported by the Heart and Stroke Foundation Career Award following an open peer-reviewed competition. The opinions, results, and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by the ICES or the Ontario MOHLTC is intended or should be inferred. All data sets used in this study were linked using unique encoded identifiers and analyzed at the ICES. Parts of this material are based on data and information compiled and provided by the Canadian Institute for Health Information (CIHI). However, the analyses, conclusions, opinions, and statements expressed herein are those of the authors, and not necessarily those of the CIHI.

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