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

Objective — 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).

Methods — 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).

Results — 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.

Conclusions — 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.