Abstract 379: Introducing Stress-Based Quantitative Plaque Vulnerability Index for Patients with Coronary Artery Disease
Introduction: Mechanical forces play an important role in plaque progression and rupture process. It is of interest to introduce stress-based plaque vulnerability indices and to study their associations with morphology-based vulnerability indices. Stress-based indices include both mechanical and morphological conditions and may improve over image-only assessment schemes.
Method: In vivo intravascular ultrasound (IVUS) data were acquired from 14 patients (11M, 3F, mean age: 59) after voluntary informed consent. IVUS-based 3D fluid-structure interaction (FSI) models were constructed to obtain critical plaque wall stress (CPWS), strain (CPWSn), flow shear stress (CFSS), cap thickness and lipid percentage following our established procedures. 617 slices from the 14 plaques were obtained for analysis. Analogous to AHA histology-based classifications, three morphological indices with values from 0 to 4 were introduced for each slice. A lipid index was assigned depending on slice lipid percentage. A cap index was assigned according to slice minimal cap thickness. The morphological index was defined as the maximum of lipid index and cap index. Each slice was assigned a stress index (0, 1, 2, 3, or 4) according to its CPWS value by using five stress intervals with optimal match rates with morphological index. Correlations between mechanical and morphological quantities were investigated.
Results: Based on data from the 617 slices, CPWS had negative correlation with cap thickness (r = -0.6570, p<0.001) and positive correlation with lipid percentage (r=0.2209, p<0.001). CPWS correlated with morphological index positively (r=0.7725, p<0.001). CFSS correlated with cap thickness positively (r = 0.1336, p<0.001) and lipid percentage negatively (r = -0.1569, p=0.0025). CFSS correlations were weaker. The stress index correlated positively with morphological index (r=0.7939, p<0.001). The match rate between the two indices was 66.8%.
Conclusion: The results demonstrated that stress index had good agreement with morphological features closely related to plaque vulnerability. Stress index provides an opportunity for improved assessment for the 33.2% cases where two indices differ. Final validation of those indices requires large-scale patient studies.
Author Disclosures: D. Tang: Research Grant; Significant; NIH/NIBIB-R01 EB004759. L. Wang: Research Grant; Significant; NIH/NIBIB-R01 EB004759. J. Zheng: None. Z. Wu: None. A. Maehara: None. C. Yang: None. R.G. Bach: None. D. Muccigrosso: None. G.S. Mintz: None.
- © 2015 by American Heart Association, Inc.