Prevalence and quantitative assessment of macrophages in coronary plaques

Although optical coherence tomography (OCT) proved to be able to identify macrophage clusters, there are no available data on the possibility to obtain reproducible measurements of their circumferential extension and location. The purpose of the present post-hoc analysis of the CLIMA study was to revise the clinical and demographic variables of patients having coronary plaques with macrophages and to investigate the reproducibility of their quantitative assessment. A total of 577 patients out of 1003 undergoing OCT showed macrophage accumulation. Three groups were identified; group 1 (426 patients) without macrophages, group 2 (296) patients with low macrophage content (less than median value [67°] of circumferential arc) and group 3 (281) with high macrophage content arc [> 67°]. Patients with macrophages (groups 2 and 3) showed a higher prevalence of family history for coronary artery disease and hypercholesterolemia and had a significantly larger body mass index. Furthermore, group 3 had more commonly triple vessel disease and higher value of LDL cholesterol levels compared to the two other groups. The inter-observer agreement for macrophage interpretation was good: R values were 0.97 for the circumferential arc extension, 0.95 for the minimum distance and 0.98 for the mean distance. A non-significant correlation between circumferential extension of macrophages and hsCRP values was found (R = 0.013). Quantitative assessment of macrophage accumulations can be obtained with high reproducibility by OCT. The presence and amount of macrophages are poorly correlated with hsCRP and identify patients with more advanced atherosclerosis and higher LDL cholesterol levels.