Identifying a high risk cardiovascular phenotype by carotid MRI-depicted intraplaque hemorrhage

Abstract

Intraplaque hemorrhage (IPH), a component of late-stage complicated plaque, identified within carotid endarterectomy surgical specimens has been recently demonstrated to predict cardiovascular (CV) events. MRI is able to depict carotid IPH. We investigated the ability of carotid MR-depicted IPH (MR-IPH) to identify high-risk CV patients. From January 2008 to April 2011, 216 patients (mean age, 67.5 years; range 31-100) referred for neurovascular MRI at an academic tertiary care centre, underwent 3T carotid MRI with adjunct 3D high-spatial-resolution coronal imaging to detect MR-IPH. Five experienced neuroradiologists made a binary decision on the presence or absence of MR-IPH. Patients' charts were reviewed blindly for demographic and CV outcomes data. Of the patients with and without MR-IPH, 62.5 % (15/24) and 19.8 % (38/192) had a composite CV event (defined as a past myocardial infarction, coronary intervention (i.e., angioplasty, stenting or bypass graft) and/or peripheral vascular disease), respectively. The odds ratio (OR) of a composite CV event in the MR-IPH group was 6.75 (Bivariable analysis, 95 % CI 2.75-16.6, p < 0.0001) and 3.25 (Multivariable regression analysis, 1.14-9.37, p = 0.028). MR-IPH had the highest OR of a prior CV event compared to other variables including age, sex, hypertension and stenosis. The OR of individual CV events was also significant: MI (3.35, 95 % CI 2.11-14.2, p < 0.01), coronary stenting (26.4, 95 % CI 8.80-79.4, p < 0.01), coronary angioplasty (21, 95 % CI 4.84-91.1, p < 0.01), and PVD (3.35, 95 % CI 1.09-10.3, p < 0.05). MR-IPH is independently associated with prior CV events in patients who are evaluated for neurovascular disease. Carotid MR-IPH, employed easily in routine clinical practice, is emerging as an indicator of systemic vascular disease and may potentially be a useful surrogate marker of CV risk including in those already undergoing neurovascular imaging.