Focal and Multi-focal Plaque Macrophage Distributions in Patients with Acute and Stable Presentations of Coronary Artery Disease

Objectives: This study was designed to utilize optical coherence tomography (OCT) images of coronary atherosclerotic plaque macrophages to investigate the relationship between macrophage distributions and clinical syndrome.

Background: The relative significance of focal macrophage infiltration and generalized coronary inflammation for predicting acute coronary events is a currently a source of considerable controversy in cardiology. Lack of a high-resolution cross-sectional imaging modality has limited macrophage evaluation in vivo.

Methods: Intracoronary OCT imaging was performed at culprit and non-culprit plaques in patients presenting with stable angina pectoris, unstable angina pectoris,and ST-segment elevation myocardial infarction. Macrophage densities were quantified from these images and analyzed with respect to the clinical presentations of the patients under investigation.

Results: A significantly greater macrophage density was found in unstable patients, both for fibrous and lipid-rich plaques (p = 0.025 and p = 0.002, respectively). Within each patient, the macrophage densities at culprit and non-culprit lesions correlated significantly (r = 0.66, y = 0.88x + 0.43, p = 0.01). Sites of plaque rupture demonstrated a greater macrophage density than non-ruptured sites (6.95 +/- 1.60%, 5.29 +/- 1.17%; p = 0.002). Surface macrophage infiltration was a stronger predictor of unstable clinical presentation than subsurface infiltration for culprit lesions (p = 0.035) but not for remote lesions (p = 0.80).

Conclusions: Our results demonstrate that increases in both multi-focal and focal macrophage densities are highly correlated with symptom severity. By providing a means of detecting increases in plaque macrophage content before an acute event, this technique may aid in determining prognosis and guiding preventive therapy.