Number of Yellow Plaques Detected in a Coronary Artery Is Associated With Future Risk of Acute Coronary Syndrome

OBJECTIVES: We sought to test whether the risk of acute coronary syndrome (ACS) can be estimated by angioscopy. BACKGROUND: Disruption of vulnerable plaque and subsequent thrombosis is regarded as a major mechanism of ACS. Although yellow plaques are supposedly vulnerable, the association between angioscopically determined extent of coronary atherosclerosis and risk of ACS events has not been reported. METHODS: Patients (n = 552) who received catheterization and angioscopic examination for the diagnosis of coronary artery diseases were prospectively included and followed up for new onset of ACS events. Yellow color intensities of all detected yellow plaques were graded as 1, 2, or 3 according to the standard colors. Number of yellow plaques (NYP) in a coronary artery and maximum color grade of detected yellow plaques (maxYP) were determined. Association between the incidence of ACS events and angioscopic findings were analyzed. RESULTS: Follow-up interval was 57.3 +/- 22.1 months. Acute coronary syndrome events were detected in 39 patients (7.1%). Although maxYP was not statistically different (2.0 +/- 0.7 vs. 1.8 +/- 0.9; p = 0.18), NYP was higher in the patients with an ACS event than those without the event (3.1 +/- 1.8 vs. 2.2 +/- 1.5; p = 0.008). Patients with NYP > or =2 and those with NYP > or =5 had 2.2- and 3.8-fold higher event rates, respectively, than those with NYP 0 or 1 (9.0% and 15.6%, respectively, vs. 4.1%; p = 0.02). Multivariate logistic regression analysis revealed NYP and multivessel disease as the independent risk factors of ACS events. CONCLUSIONS: Patients with multiple yellow plaques per vessel have a higher risk of suffering ACS events than those with NYP 0 or 1. Angioscopy would be useful to detect vulnerable patients.