Increase of scavenger receptor A-positive monocytes in patients with acute coronary syndromes.

To evaluate the utility of the scavenger receptor A (SRA) index (no. SRA(+) monocytes observed in 10 high-power fields of peripheral blood (PB) smear samples, normal upper limit <30) as the indication of disrupted, fissured, or eroded plaque, 225 patients with acute myocardial infarction (AMI), 79 with unstable angina (UA) and 91 with stable angina (SA) were examined. Thrombus was gathered from 95 of 205 sequential AMI patients (46.3%), and classified into platelets, mixed, and two kinds of residual mural thrombus (RMT). RMT was observed in 56 of 169 (33.1%) AMI patients with SRA index > or =30 at hospitalization. The SRA index of 82.4% of AMI, and 75.9% of UA, and 70.3% of SA patients was > or =30 at hospitalization. For 36 AMI patients who initially had an SRA index of <30 at hospitalization, it exceeded 30 within 2 days, and the SRA index rapidly increased in most AMI patients after hospitalization. SRA(+) monocytes were considered to differentiate from SRA(-) monocytes in PB. An abnormally high SRA index is considered to be a useful indication of disrupted or fissured or eroded plaque.