Relationship between serum interleukin-6 levels and severity of coronary artery disease undergoing percutaneous coronary intervention

Background: Cytokines play a potential role in atherosclerosis pathogenesis and progression. We investigated the association of interleukin-6 (IL-6) with the angiographic severity of coronary artery disease (CAD). Methods: 310 angiografically diagnosed CAD patients and 210 controls were enrolled in this study. CAD patients were stratified according to IL-6 cut-off value into high levels IL-6 group (≥ 9.5 pg/mL) and low levels IL-6 group (< 9.5 pg/mL). The severity of CAD was assessed according to Gensini score (GS), artery stenosis degree and the number of vessels involved. The mean age was 60.3 ± 11.0 years. Results:The level of IL-6 in patients was increased compared to controls and ranged from 1.5 to 3640.0 pg/mL. High levels of IL-6 were significantly associated with high levels of GS (>40) but not with stenosis degree and vessel score. GS levels were significantly more elevated in patients with high levels of IL-6 group than in low IL6 levels patients (60.6 ± 39.5 vs 46.7 ± 37.2; p = 0.027). The analysis of the ROC curve performed in myocardial infarction patients showed that IL-6 (AUC: 0.941 (CI 95% 0.886, 0.997; p<0.001) could be a powerful predictor marker in evaluating the infarct size after myocardial infarction when compared to myonecrosis biomarkers. Conclusions: IL-6 levels were associated with the severity of CAD assessed by the GS. Based on the highest levels of IL-6 measured in patients with STEMI, our study strongly suggests that IL-6 could be a powerful marker in evaluating the myocardial necrosis. ClinicalTrials.gov Number: NCT03075566 (09/03/2017)