Abstract 12595: Early and Persistent Accumulation of Lipid is Associated With the Development of Thin-cap Fibroatheromas
Introduction: Rupture of a thin cap fibroatheroma (TCFA) is the dominant mechanism of acute coronary syndromes. Intravascular imaging permits the in vivo evaluation of plaque morphology and content. Serial assessment with intravascular ultrasound (IVUS) and near infrared spectroscopy (NIRS) may provide insight into the subsequent development of TCFAs. Hypothesis: We hypothesized that early and persistent accumulation of plaque lipid, detected by NIRS, predicts the future development of coronary TCFAs.
Methods: Diabetes and hypercholesterolemia were induced and maintained in 18 Yorkshire pigs. Multi-vessel diagnostic evaluation was performed at 3, 6 and 9 month time points with IVUS, measuring vessel atheroma and necrotic core volumes, and NIRS to measure lipid core burden index (LCBI). At 9 months animals' histology was performed at 5-mm intervals with the results correlated to in vivo data. The relationship between LCBI and the presence or absence of TCFA was determined with analysis of variance.
Results: Five pigs experienced sudden cardiac death. Serial IVUS and NIRS were performed at 3, 6, and 9 months on the remaining 13 animals (n=37 arteries) with histology obtained at 9 months. Per-vessel LCBI averaged 33.2±29.6, 55.5±65.4, and 52.1±50.2 at 3, 6, and 9 months respectively. LBCI increased between 3 and 6 months by 39.4% (p < 0.01), but was stable between 6 and 9 months (-5.2%, p = 0.41). Among vessels with an increase in LCBI between 3 and 6 months (n = 22) necrotic core volume at 9 months by IVUS was significantly greater than those vessels in which LCBI remained stable or decreased (142±148 µm3 vs. 18.9±32 µm3 ; < 0.01). There were a total of 69 sections containing TCFA by histology with an average cap thickness of 65.6 ± 23.9 µm. The [[Unable to Display Character: ∆]]LCBI between 3 and 6 months was greater in vessels in which TCFAs were identified (55.3+16.9 vs. 3.3+16.0; p = 0.03). The ▵ LCBI between 6 and 9 months was not related to the necrotic core volume or the presence of thin cap FA.
Conclusions: In this model, the early and persistent accumulation of lipid between 3 and 6 months within lipid core plaque predicted the development of thin-cap fibroatheromas at 9 months.
- Intravascular ultrasound/Doppler
- Acute coronary syndromes
- Coronary artery disease
- Vulnerable plaque
- © 2012 by American Heart Association, Inc.