Associations between plasma C-reactive protein levels and the severities of coronary and aortic atherosclerosis

Limited correlations between C-reactive protein (CRP) and coronary artery disease (CAD) have been reported. Recently, MRI became a useful tool for non-invasively evaluating atherosclerotic plaques in thoracic and abdominal aortas.

To elucidate the associations between plasma CRP levels and the severities of coronary and aortic atherosclerosis, we performed aortic black-blood MRI in 136 patients undergoing coronary angiography. For each patient, 9 slices of thoracic aorta and 9 slices of abdominal aorta were obtained at 12-mm intervals, and the plaque extent in each slice was scored. The degree of aortic atherosclerosis is represented as the sum of scores. The degree of coronary atherosclerosis is represented as the number of >50% stenotic vessels and >25% stenotic segments.

CAD (>50% stenosis) was present in 96 patients. Patients with CAD had higher CRP levels than those without CAD (median 0.78 vs. 0.48 mg/L, p<0.02). CRP levels tended to increase depending on the number of stenotic vessels: 0.48, 0.70, 0.74, and 0.88 mg/L (p=NS). CRP correlated weakly with the number of stenotic segments (r=0.21). Regarding aortic atherosclerosis, 136 patients were divided into quartiles by plaque score. CRP levels increased stepwise in quartiles: 0.40, 0.56, 1.08, and 1.10 mg/L (p<0.001). CRP levels also correlated with the plaque score (r=0.38). In multivariate analysis, aortic atherosclerosis was an independent factor for CRP levels, but coronary atherosclerosis was not.

Plasma CRP levels correlated with the severities of both coronary and aortic atherosclerosis, but CRP levels are more likely to reflect the severity of aortic atherosclerosis than coronary atherosclerosis.