Plasma osteopontin as a predictor of coronary artery disease: association with echocardiographic characteristics of atherosclerosis

Osteopontin (OPN), a bone-related protein, is present within the atherosclerotic plaques, most strikingly in calcified plaques. Valvular calcifications are accepted as a part of the spectrum of atherosclerosis and are associated with atherosclerotic calcification in the coronary arteries. The study aimed to evaluate the association of plasma OPN with the presence and extent of coronary stenosis, mitral annular calcification (MAC), and aortic valve sclerosis in stable angina patients. We studied 120 subjects who underwent coronary angiography because of ischemic chest pain. Coronary artery disease (CAD) was defined as > or = 50% stenosis in > or = 1 coronary artery. MAC and aortic valve sclerosis were detected by echocardiography. Lipid profile, high sensitive C-reactive protein (hsCRP), and OPN were measured in all studied subjects. Patients with CAD had increased plasma OPN when compared with those without CAD (P < 0.001). Plasma OPN levels were significantly positively correlated with atherogenic lipid profile, hsCRP, MAC grading, aortic valve sclerosis grading, and the number of stenosed coronary vessels in CAD patients. In multivariate analysis, OPN was an independent predictor of CAD (P = 0.01), MAC (P = 0.01), and aortic valve sclerosis (P = 0.04). In conclusion, OPN is an independent predictor of MAC and aortic valve sclerosis. Plasma OPN levels reflect the extent of coronary stenosis and can be used as a biomarker to identify patients with coronary atherosclerosis.