Interleukin 6 plasma levels predict with high sensitivity and specificity coronary stenosis detected by coronary angiography

In recent years new biomarkers able to measure the coronary atherosclerotic burden have been investigated. The aim of the present study was: i) to measure plasma levels of four biomarkers: C reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1), interleukin 6 (IL-6), 8-isosprostane (8-ISO), in a series of patients undergoing coronary angiography; ii) to assess the power of the biomarkers to predict critical coronary stenosis detected by angiography. The study population consisted of a group of 438 subjects undergoing coronary angiography; 160 patients with 0, 1, 2, or 3 critical vessels were selected, and biomarkers plasma levels were measured in plasma samples obtained before the procedure. The most predictive biomarker was then assayed in 120 patients with critical stenosis and 120 unmatched patients without stenosis. CRP, sICAM-1, IL-6 and 8-ISO plasma levels increased with the number of diseased vessels. All biomarkers were good predictors of critical stenosis (receiver-operator-curve [ROC] areas; CRP = 0.880, IL-6 = 0.936, sICAM-1 = 0.907, 8-ISO = 0.873). IL-6 was confirmed in an expanded sample of 240 subjects to be the best predictor with a ROC area = 0.959. With a threshold of 3.6 ng/l, a 100% sensitivity (120/120) and a 90% specificity (108/120) was observed. In conclusion, IL-6, sICAM-1, CRP and 8-ISO are predictive of CAD. IL-6 predicts critical coronary stenosis with the highest sensitivity and specificity.