It remains unclear whether measures of magnetic resonance imaging plaque characteristics are associated with cardiovascular disease events independent of plaque burden at the population level.
Magnetic resonance imaging (MRI) of high-risk plaque characteristics have identified cerebrovascular events prospectively in asymptomatic patients, but, despite this progress it remains uncertain whether measures of MRI plaque characteristics are associated with cardiovascular disease events independent of plaque burden at the population level.
A recent study, published in JAMA, looked to determine whether measures of plaque characteristics through use of MRI are independently associated with cardiovascular disease events, when adjusted for carotid artery (CA) wall thickness, in an asymptomatic community-based cohort.
Between January 2004 and December 2005, the study enrolled 1256 men and women with CA intima media thickness of roughly the 68th percentile or higher. All participants were imaged on 1.5-T MRI systems with a 4-element phased-array carotid coil and standard MRI protocols. Measures of MRI CA plaque burden included total carotid wall volume, maximum carotid wall thickness, lumen and wall area, normalized wall index, and maximum stenosis.
Cardiovascular disease events were defined by the authors as the composite of incident coronary heart disease events or incident ischemic strokes. These events included definite or probable myocardial infarction, coronary heart disease death, and the occurrence of a coronary artery bypass surgery or angioplasty during follow-up.
Of the 1256 participants enrolled, 701 (55.8%) were women. CA plaques in participants with incident cardiovascular disease events (172 [13.7%]) compared with those without (1084 [86.3%]) had a higher normalized wall index (median interquartile range [IQR], 0.48 [0.36-0.62] vs 0.43 [0.34-0.55]; P = .001), maximum CA wall thickness (median [IQR], 2.22 [1.37-3.52] mm vs 1.96 [1.29-2.85] mm; P = .01), maximum CA stenosis (median [IQR], 5% [0%-22%] vs 0% [0%-13%]; P < .001), and when present, a larger lipid core volume (median [IQR], 0.05 [0.02-0.11] mL vs 0.03 [0.01-0.07] mL; P = .03), respectively.
The occurrence of a lipid core was independently associated with incident cardiovascular disease events when adjusted for traditional cardiovascular disease risk factors and maximum CA wall thickness (HR, 2.48; 95% CI, 1.36-4.51; P = .003), however, the presence of calcification was not.
The authors found that in asymptomatic participants, the presence of a CA lipid core on MRI is associated with incident cardiovascular disease independent of maximum CA wall thickness. Furthermore, the authors noted that when present, noninvasive MRI carotid plaque characteristics improved risk prediction of incident cardiovascular disease events.
Brunner G, Virai S, Sun W, et al. Associations between carotid artery plaque burden, plaque characteristics, and cardiovascular events. Published online November 18, 2020. JAMA Cardiol. doi:10.1001/jamacardio.2020.5573