BackgroundTo investigate the correlation between lg (circSCMH1/miR-874) and acute coronary syndrome (ACS), acute myocardial infarction (AMI), and carotid plaque stability.Methods701 patients were divided into stable coronary artery disease (SCAD), ACS, and control groups. Furthermore, 225 patients who underwent carotid ultrasound were selected from the above 701 patients and were divided into low-risk plaque, medium-to-high risk plaque, and control (without carotid plaques) groups. We collected their baseline characteristics and measured the contents of exosomal circSCMH1 and miR-874 in peripheral blood. Then lg(circSCMH1/miR-874) was calculated and statistical analysis was performed.ResultsThe lg (circSCMH1/miR-874) values of ACS, SCAD, and the control group decreased successively (P ConclusionLg (circSCMH1/miR-874) is closely associated with coronary and carotid plaque stability.</p