Association between inflammatory biomarkers and thin-cap fibroatheroma detected by optical coherence tomography in patients with coronary heart disease

INTRODUCTION The relationship between plaque morphology detected by optical coherence tomography (OCT) and inflammatory biomarkers is not well known. MATERIAL AND METHODS This study included 47 patients with ischemic heart disease (22 patients with acute coronary syndrome and 25 patients with effort angina pectoris) who underwent percutaneous coronary intervention (PCI). Before PCI, peripheral blood levels of the inflammatory biomarkers high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) were measured. The OCT can detect thin-cap fibroatheroma (TCFA), a lesion with high potential for adverse cardiac events. We investigated the relationships between TCFAs in culprit lesions detected by OCT and the peripheral blood levels of these biomarkers. RESULTS We observed 12 lesions detected as TCFAs. The natural logs of hs-CRP and IL-6 levels in the TCFA group were higher than those in the non-TCFA group (hs-CRP 0.87 (-0.96 to 0.87) vs. -0.47 (-0.92 to 0.30) mg/l, p = 0.027; and IL-6 1.63 (0.63-3.23) vs. 0.53 (-0.21 to 1.05) pg/dl, p = 0.005, respectively). In multivariate logistic regression analysis, log IL-6 was an independent predictor for TCFA detected by OCT (log IL-6, 0.970 pg/dl, p = 0.023). Receiver operating characteristic curve analysis confirmed that IL-6, compared to hs-CRP, has a higher area under the curve for predicting TCFA (0.783 vs. 0.715, respectively). CONCLUSIONS Peripheral blood levels of both hs-CRP and IL-6 were associated with TCFAs, as detected by OCT. Moreover, IL-6 has a higher potential than hs-CRP for predicting TCFA.