Incremental value of carotid intraplaque hemorrhage for discriminating prior coronary events

Background: The value of noninvasive assessment of carotid plaque composition in identifying patients with high coronary risk remains elusive. We sought to determine whether and which carotid plaque components are associated with prior coronary events independent of traditional risk factors and plaque burden. Methods: Asymptomatic subjects with 50-79 % carotid stenosis by ultrasound were imaged with a multi-contrast carotid MRI protocol at 1.5 T. The independent associations between plaque components (fibrous tissue, calcification, lipid-rich necrotic core [LRNC] and intraplaque hemorrhage [IPH]) and prior coronary events, including myocardial infarction and coronary revascularization, were evaluated by controlling for traditional risk factors and plaque burden metrics. Results: A total of 159 subjects (69.7 ± 9.0 years, 84 % males) were included. Prior coronary events were documented in 66 (42 %) subjects, and were associated with a larger carotid plaque burden consisting of more LRNC and calcification. Additionally, a higher prevalence of IPH was observed in subjects with prior coronary events (32 % vs. 15 %, p = 0.019). In multivariate analysis, the percent wall volume was an independent discriminator among plaque burden metrics after accounting for traditional risk factors (odds ratio per 1-SD increase: 1.7 [1.2, 2.6]); the presence of IPH remained as a significant discriminator after accounting for traditional risk factors and percent wall volume (odds ratio: 2.9 [1.1, 7.6]) while other compositional metrics did not. Conclusions: IPH in the carotid artery was independently associated with prior coronary events. IPH imaging may provide incremental information on patients’ coronary risk beyond traditional risk factors and carotid plaque burden assessment.