Abstract 15019: Relation Between Fibrous Cap Thickness and No Reflow Phenomenon in Patients with Acute Myocardial Infarction
Background: No reflow phenomenon after percutaneous coronary intervention (PCI) has been shown to lead to poorer outcome in patients with acute myocardial infarction (AMI). Recent studies have reported about possible causes of this phenomenon, such as distal embolization of thrombus and plaque contents. Little is known about the surface morphologies of culprit coronary artery in AMI and it is still difficult to predict no reflow phenomenon. We assessed the hypothesis that released substances from easily ruptured plaque due to PCI might play a role for no reflow phenomenon in AMI.
Objectives: The aim of this study is to investigate the predictor of no reflow phenomenon using optical coherence tomography (OCT) as well as intravascular ultrasound (IVUS).
Methods: 45 patients with AMI, who underwent OCT and IVUS before primary PCI were included. No reflow phenomenon was defined using coronary angiography as decrease in TIMI flow grade without mechanical coronary obstruction. Fibrous cap thickness was measured by OCT, and plaque characteristics were determined using previously validated criteria. Arterial remodeling and attenuated plaque were assessed by IVUS.
Results: No reflow phenomenon occurred in 7 cases (group 1), and was not found in 38 cases (group 2). Fibrous cap thickness of group 1 was smaller (45.7±19.5 micrometer in group 1, 69.0±55.4 micrometer in group 2, p=0.0076), positive remodeling was more frequent (85.7% in group 1, 39.3% in group 2, p=0.028). Frequency of attenuated plaque, plasma C-reactive protein level, lipid profile, number of diseased vessels and stent size were not different significantly between two groups. Multiple logistic regression analysis indicated that thin-cap fibroatheroma was the strongest predictor of no reflow phenomenon (odds ratio 2.76, 95% confidence interval; 1.56 to 160.51; p=0.0196), and that neither attenuated plaque (p=0.7208) nor positive remodeling (p=0.1202) was significant predictors.
Conclusions: No reflow phenomenon increased in cases presenting thin-cap fibroatheroma. OCT highly predicted no reflow phenomenon, suggesting that OCT is useful for predicting no reflow phenomenon in primary PCI in AMI.
- © 2011 by American Heart Association, Inc.