Abstract 15068: Impact of Out-stent Plaque Vulnerability on Neointimal Stent Coverage in Patients with Acute Coronary Syndrome: Intracoronary Angioscopic and Ultrasonic Quantification
Background: Intracoronary angioscopy is a unique imaging device to visualize in-stent neointimal coverage (ISNC). iMAP intravascular ultrasound (IVUS) quantitates not only plaque burden but also its tissue characterization. The aim of this study was to clarify the healing process of stented vulnerable plaques in patients with acute coronary syndrome (ACS).
Methods: In 27 patients with ACS (18 acute myocardial infarction and 9 unstable angina), a bare metal stent (n=6) or a drug-eluting stent (n=21) was successfully implanted at each culprit lesion. Subsequently, out-stent vulnerable plaques were characterized by 40 MHz iMAP IVUS, i.e. out-stent plaque volume (OSPV) and its % tissue fractions of fibrotic, lipidic, necrotic, or calcified volumes. OSPV was defined as integral calculation of out-stent plaque area per 0.5mm interval, from proximal to distal edge of each stent. At one-year follow-up (chronic phase), in addition to iMAP IVUS analysis, coronary angioscopy was performed to assess ISNC grade (grade 0, no coverage; grade 3, full coverage). In the protocol period, patients received optimal medical treatments including statins, anti-platelet agents, etc.
Results: Although OSPV did not change significantly during the protocol (147.5±84.5 vs. 146.2±88.8mm3, acute vs. chronic phase, p=0.86), its % tissue fractions significantly changed, indicating that out-stent vulnerable plaques were stabilized at chronic phase (fibrotic 47.1±7.6 vs. 53.2±7.7%, P < 0.0001; lipidic 11.9±2.9 vs. 10.2±2.9%, P <0.01; necrotic 30.2±7.0 vs. 25.3±7.3%, P = 0.0001; calcified 2.9±1.6vs. 4.1±2.4%, P<0.01; acute vs. chronic phase). Correlation analyses were performed between angioscopic ISNC grades and iMAP IVUS parameters at chronic phase. We found positive correlation of ISNC grades to % fibrotic tissue (R=0.537, P<0.01), negative to % lipidic (R=-0.42, P<0.05), and negative to % necrotic tissue (R=-0.56, P<0.001).
Conclusions: Out-stent plaque vulnerability appeared to delay angioscopic ISNC at one-year follow-up, suggesting that the more aggressive medication might be necessary to prevent late in-stent thrombosis and to stabilize the stented coronary plaques in ACS patients.
Author Disclosures: K. Kawai: None. M. Ichikawa: None. T. Takagi: None. M. Asai: None. Y. Takei: None. K. Fukuda: None. S. Yoshima: None. T. Oshita: None. Y. Kijima: None.
- © 2014 by American Heart Association, Inc.