Multicentric inflammation in epicardial coronary arteries of patients dying of acute myocardial infarction

Objectives We sought to test the hypothesis of whether inflammatory cell infiltration in patients dying of an acute myocardial infarction (MI) is a multifocal event involving multiple coronary branches. Background Coronary instability is thought to reflect local disruption of a single vulnerable plaque. However, previous postmortem studies have not addressed the question of whether activation of inflammatory cells, particularly T lymphocytes, is limited to the culprit lesion only or rather diffuse in the coronary circulation. Methods We performed a systematic flow cytometric study in three groups of autopsied patients (group 1 = acute MI; group 2 = old MI; group 3 = no ischemic heart disease). Cell suspensions of enzymatically digested coronary arteries were stained for flow cytometry with CD3, CD68, alpha-smooth muscle actin, and human leukocyte antigen (HLA)-DR antibodies. Results The coronary plaques showed: 1) a higher proportion of inflammatory cells in groups 1 and 2 than in group 3; 2) a higher percentage of T lymphocytes in group 1 than in group 2 (11.67 ± 0.70% vs. 5.67 ± 0.74%, P = 0.001) and in group 2 than in group 3 (p = 0.008); and 3) diffuse cell activation in the whole coronary tree of group 1, but not of group 2 subjects. Conclusions Our study suggests that lymphocytes may play a key role in coronary instability by determining activation of various cellular types throughout the coronary circulation. Activated T lymphocytes and their products may well represent a new target in both the treatment and prevention of acute coronary syndromes.