Detection of intraplaque hemorrhage by magnetic resonance imaging in symptomatic patients with mild to moderate carotid stenosis predicts recurrent neurological events

Background: Carotid endarterectomy is beneficial in severe (>70%) symptomatic carotid stenosis. The risk of stroke in moderate carotid stenosis (50%-69%) is modest, and so the role of carotid endarterectomy in this group is unclear. Intraplaque hemorrhage is associated with advanced atherosclerosis and can be detected in the carotid arteries by magnetic resonance imaging. This study evaluates whether magnetic resonance imaging detected intraplaque hemorrhage (MR IPH) can identify patients with symptomatic mild to moderate carotid stenosis who are at higher risk of ipsilateral transient ischemic attack (TIA) and stroke. Methods: Prospective longitudinal cohort study of symptomatic patients with mild to moderate (30%-69%) carotid stenosis followed up for 2 years after imaging for IPH using magnetic resonance imaging. Results: Sixty four participants were followed up for a median of 28 months (interquartile range 26-30) after MRI of the carotid arteries. Thirty-nine (61%) ipsilateral arteries showed intraplaque hemorrhage. During follow-up, five ipsilateral strokes and a total of 14 ipsilateral ischemic events were observed. Thirteen of these ischemic events, of which five were strokes, occurred in those with ipsilateral carotid intraplaque hemorrhage (hazard ratio = 9.8, 95% confidence interval 1.3-75.1, P=.03). Conclusions: MR IPH is a good predictor of ipsilateral stroke and TIA in patients with symptomatic mild to moderate (30%-69%) carotid stenosis. This technique could help in the selection of patients for carotid endarterectomy.