Elevated C1rC1sC1inh levels independently predict atherosclerotic coronary heart disease

► Complement activation in ischaemic heart disease. ► Classical complement pathway is activated in coronary atherosclerosis. ► C1rC1sC1inh is a promising cardiovascular biomarker. Clinical studies as well as animal models emphasized the importance of the complement system in the pathogenesis of coronary atherosclerosis and cardiovascular diseases. Our aim was to examine the extent and clinical implication of complement system activation in patients with stable atherosclerotic coronary heart disease (ACHD). Seventy-six patients with stable angina pectoris (SAP) scheduled for elective coronary angiography were enrolled into the study. Percutaneous coronary intervention (PCI) was performed in 24 patients, in 27 patients (NOPCI group) the coronary angiography showed significant stenosis and bypass surgery (CABG) or optimal medical therapy (OMT) were advised, whereas in 25 patients the coronary angiography was negative (NC group). 115 volunteers served as healthy controls (HC). In all individuals, the plasma level of several complement activation products – C1rC1sC1inh, C3bBbP and SC5b-9 – were determined on admission, strictly before the coronary angiography. In patients with angiographically proven ACHD (PCI and NOPCI groups), the baseline C1rC1sC1inh levels were significantly higher compared to NC group and HC (p