Relationship Between Macrophage Arc and Plaque Vulnerability in Patients With Coronary Artery Disease.

BACKGROUND: Macrophages are key drivers of coronary artery plaque development and can be detected via optical coherence tomography as circumferential regions. However, the association between macrophage arc and plaque vulnerability remains unclear. OBJECTIVES: The objective of the study was to evaluate the correlation between macrophage arc and vulnerable plaques. METHODS: This multicenter, retrospective study enrolled consecutive patients with coronary artery disease who underwent optical coherence tomography (January 2017-April 2023). Macrophage arc was evaluated using maximum arc, mean arc, and mean arc score (MAS) in the target vessel. The mean arc and MAS were calculated as the total detectable macrophage arc or score of each frame, divided by imaged vessel segment length (mm). Furthermore, the association between macrophage arc, plaque vulnerability, and acute myocardial infarction (AMI) at admission was investigated. RESULTS: Overall, 1,129 patients (1,278 vessels; 1,525 vulnerable plaques) were enrolled. The macrophage arc was significantly increased in cases of plaque rupture (PR), thin-cap fibroatheroma (TCFA), and AMI cases (P < 0.0001). Both the mean arc and MAS were markedly higher in regions adjacent to PR or TCFA compared with the entire segment (P < 0.0001). Multivariate analyses demonstrated that maximum arc, mean arc, and MAS were correlated with PR, TCFA, and AMI. Receiver operating characteristic analysis identified optimal cutoff values-maximum arc ≥156.5°, mean arc ≥78.89°/mm, and MAS ≥2.34-each significantly associated with PR, TCFA, and AMI, respectively (all P < 0.001). CONCLUSIONS: Macrophage arcs are associated with plaque vulnerability and AMI. Further external validation and prospective studies are needed to confirm these observations.