Plasma YKL-40 in relation to the degree of coronary artery disease in patients with stable ischemic heart disease

Background. YKL-40 is a glycoprotein secreted by macrophages and neutrophils in tissues with inflammation. Plasma YKL-40 is increased in patients with coronary artery disease (CAD) and associated with cardiovascular and all-cause mortality. Furthermore, plasma YKL-40 seems related to the number of diseased main vessels in patients with stable CAD. The aim was to further study the relation between YKL-40 and stenosis degree, stenosis type and actual ischemia in stable CAD patients. Methods. Plasma YKL-40 and hsCRP levels were determined from 206 consecutive patients with stable angina pectoris admitted for coronary angiography. Plasma YKL-40 in 245 healthy subjects was used for comparison. In addition to one to three vessel stenosis scores, two new scores for evaluating coronary angiographies were established for discriminating between focal and diffuse CAD and the extent of myocardial ischemia. Results. YKL-40 levels in CAD patients (median: 52 mu g/L and quartiles: 37-85 mu g/L) were significantly increased (p < 0.001) compared to the healthy controls. In univariate analyses plasma YKL-40 was significantly associated with ischemic myocardium score, age, hypertension, peripheral vascular disease and serum creatinine levels. In multivariate analyses YKL-40 was related to hsCRP, peripheral artery disease, hypertension, and statin treatment. Conclusions. Plasma YKL-40 was increased in patients with CAD compared to controls. YKL-40 was related to the ischemic myocardium, but not to degree of CAD using different scoring systems. Therefore, YKL-40 is not related to the extent of CAD, but to some other pathophysiological mechanisms of importance for the prognosis.