Inflammation markers in patients with coronary artery disease - comparison of intracoronary and systemic levels

Background and aim: Raised levels of inflammation markers are associated with worse prognosis in patients with coronary artery disease. It is generally believed, although it has never been proven, that inflammation markers are released from (un)stable plaques in coronary arteries. We investigated this issue by directly comparing levels of inflammation markers in coronary and systemic blood. Patients and methods: Patients with acute coronary syndrome (N = 11), stable angina pectoris (N = 10) and controls with noncoronary origin of chest pain (N = 9) were included in the study. Intracoronary blood samples were taken at the culprit lesion in the coronary artery in patients with acute coronary syndrome and from any coronary artery in the other two groups, together with systemic blood samples from the femoral vein and artery. Levels of high-sensitivity C reactive protein (hsCRP), interleukin 6, interleukin 8, interleukin 10, soluble receptor for interleukin 2 (tR IL-2) and myeloperoxidase were measured in all samples. Results: We found significantly elevated levels of hsCRP and interleukin 10 in patients with acute coronary syndrome compared with patients with stable angina and the control patients. Notably, we did not find any difference between intracoronary and systemic levels of any inflammatory marker in patients with acute coronary syndrome. Furthermore, no difference between intracoronary and systemic levels of markers was present in patients with stable angina or in the control group. Conclusions: We observed that excess circulating inflammation markers, being characteristic of unstable coronary artery disease, are released from noncoronary sources. Thus, it may be speculated that systemic inflammation precedes local inflammation at the plaques, thereby transforming coronary disease from a stable to an unstable form.