Impact of culprit plaque composition on the no-reflow phenomenon in patients with acute coronary syndrome - An intravascular ultrasound radiofrequency analysis

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 I 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 hi her percentage of necrotic core companent 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=0.0 15). Conclusion Culprit plaques of patients with the no-reflow phenomenon differ from those in patients without the no-reflow phenomenon.