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Session: Vascular I
Session starts: Thursday 26 January, 14:30
Presentation starts: 15:00
Room: Room 559

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Aikaterini Tziotziou (Erasmus Medical Center)
Jolanda Wentzel (Erasmus Medical Center)
Ali Akyildiz (Erasmus Medical Center)

Abstract:
Atherosclerosis is one of the most widespread diseases in our cardiovascular system and a primary cause of death as its progression and rupture can lead to myocardial attack or stroke [1]. Atherosclerotic plaque progression over time in coronary arteries is affected by local hemodynamic and biomechanical factors, such as the Wall Shear Stress (WSS) and the Plaque Structural Stress (PSS) [2]. Low WSS is known to be associated with plaque progression but the association between PSS, and its combination with WSS, towards plaque progression has not been well-established yet [2]. In this work, we study the effect of PSS and WSS on human coronary plaque progression. Forty non-stented, non-culprit coronary arteries (IMPACT study) [3] were imaged at two time points (baseline and one-year follow-up) using combined near infrared spectroscopy intravascular ultrasound (NIRS-IVUS) and optical coherence tomography (OCT). The 2D plaque geometries were extracted from the combined imaging data. PSS (max principal stress) in patient-specific cross-sections was calculated via ABAQUS, by using the material properties of individual plaque components [2, 4] and the backward incremental method [4] to quantify and incorporate the initial stresses. The individual and combined impact of PSS and WSS on plaque progression was studied using Linear Mixed Models in SPSS. The 3D artery geometries were divided into 1,5mm/45o sectors and the statistical analyses were sector-based. The plaque burden and wall thickness change were used as parameters to quantify plaque progression. For the statistical analysis, the arterial sectors were divided into three tertiles (low, mid, high) with respect to PSS and WSS and categorised as healthy and diseased based on 0.5mm thickness threshold, including NIRS+ and NIRS- sectors. The effect of PSS and WSS individually, as well as when combined, on the plaque burden and wall thickness change were statistically significant. Specifically, low WSS was associated with plaque progression, while low and high PSS was associated with increased plaque burden and wall thickness change in diseased and healthy sectors, respectively. The analysis of the combined effect of PSS and WSS on plaque progression showed that healthy sectors of high PSS with low WSS and diseased sectors of low PSS with low WSS had the greatest plaque burden and wall thickness increase. We hope that this study will provide great insights for better understanding the plaque growth mechanisms and developing plaque progression prediction models. 1. Shah, P et al., Thrombosis, 2015:634983, 2015. 2. Costopoulos, C et al., Eur Heart J., 40:1411-1422, 2019. 3. Hartman, E et al., J. of Cardiovasc. Trans. Res., 14:416–425, 2021. 4. Akyildiz, A C et al., Computer. Methods in Biomech. and Biomed. Eng., 19: 771–779, 2016.