Impact of Culprit Plaque Composition on the No-Reflow Phenomenon in Patients With Acute Coronary Syndrome

An Intravascular Ultrasound Radiofrequency Analysis

Abstract

Background The difference in the culprit plaque composition of acute coronary syndrome (ACS) patients with and without the no-reflow phenomenon has not been fully evaluated. Methods and Results Intravascular ultrasound radiofrequency data of culprit plaques were obtained and analyzed in 49 ACS patients. The no-reflow phenomenon was defined as a decrease of at least 1 grade in `Thrombolysis In Myocardial Infarction' flow immediately after mechanical dilatation compared with before mechanical dilatation, with no evidence of thrombus, spasm, or dissection. The no-reflow phenomenon was observed in 9 individuals. Culprit plaques with the no-reflow phenomenon contained a higher percentage of necrotic core component and a smaller percentage of fibrous component than plaques in the patients without the no-reflow phenomenon (necrotic core component, 22.1±9.3% vs 11.7±7.9%, p=0.0011; fibrous component, 59.6±11.2% vs 68.3±10.2%, p=0.027). Multivariate analysis identified the percentage of necrotic core component as an independent predictor of the no-reflow phenomenon after adjustment for plaque geometry and procedural factors (odds ratio, 1.7; 95% confidence interval, 1.1 to 2.5; p=0.015). Conclusion Culprit plaques of patients with the no-reflow phenomenon differ from those in patients without the no-reflow phenomenon. (Circ J 2008; 72: 1235 - 1241)