Association between circulating monocytes and coronary plaque progression in patients with acute myocardial infarction.

BACKGROUND Monocytes and macrophages have been shown to play major roles in the progression of atherosclerosis. This study examined whether the circulating monocyte count can be used to predict coronary plaque progression of non-culprit intermediate lesions in acute myocardial infarction (AMI). METHODS AND RESULTS Intravascular ultrasound findings of non-culprit intermediate plaque in 90 patients were analyzed in the acute phase and at a 7-month follow up. A higher peak monocyte count after AMI was associated with a greater plaque volume change (r=0.32, P=0.002). Multivariate analysis showed that a peak monocyte count of > or =800 /mm(3) was an independent predictor of plaque progression (odds ratio 5.02, P=0.005). High monocyte (> or =800 /mm(3)) at baseline had a higher monocyte count at 7-month follow up than did those with a lower count (368+/-109 vs 263+/-64 /mm(3), P<0.0001). Moreover, the monocyte count at the 7-month follow up was also associated with plaque volume change (r=0.29, P=0.006). CONCLUSIONS The results suggest that circulating monocytes play an important role in the progression of coronary plaque in AMI and that the peak monocyte count during hospitalization might be a predictor of plaque progression.