Abstract 14829: Semi-quantitative Assessment of OCT-macrophage Predicts Future Development of Thin-cap Fibroatheroma in Non-culprit Lipid Plaques: A Serial Optical Coherence Tomography Study
Introduction: Previous pathological studies have demonstrated that macrophages play an important role for the deterioration of fibrous cap and the onset of acute coronary syndrome. However, the significance of macrophage on the development of thin-cap fibroatheroma (TCFA) had not been fully evaluated in vivo. Aim: To explore the impact of OCT detected macrophage on the development of TCFA in patients with coronary artery disease using serial OCT images. Methods: A total of 152 non-culprit plaques from 90 patients who had serial OCT imaging at baseline and follow-up (median 6.38 [6.07-12.5] months) were included. TCFA was defined as the plaque with the fibrous cap thickness <65μm.OCT detected macrophage was semi-quantitatively assessed in every 1mm along the entire target plaque using a previously introduced grading system; Grade 0: no macrophage, Grade 1: localized macrophage accumulation, Grade 2: clustered accumulation<1 quadrant, Grade 3: clustered accumulation≥1 quadrant but <3 quadrants, Grade 4: clustered accumulation≥3 quadrants. The summation of 0 to 4 grades was evaluated. Results: Among 45 TCFA at baseline, 19 remain as TCFA [persistent TCFA] and 26 changed to non-TCFA [resolved TCFA] at follow-up (Figure). The macrophage grade in persistent TCFA was significantly greater than that in resolved TCFA (13.0 [8.00-17.0] vs. 4.00 [2.00-8.25] (P<0.001)) at baseline. On the other hand, 11 among 107 non-TCFA at baseline changed to TCFA [acquired TCFA] at follow-up. The macrophage grade in acquired TCFA was significantly greater than that in non-TCFA (14.0 [11.0-19.0] vs. 2.0 [0.00-6.75] (P<0.001)) at baseline. The macrophage grade>7.5 at baseline had good performance in discriminating TCFA from non-TCFA at follow-up (area under the curve [AUC] = 0.884, P<0.001) (Figure). Conclusions: The semi-quantitative evaluation of OCT detected macrophage at baseline had the potential to predict the future development of TCFA in patients with coronary artery disease.