Plaque structural stress assessed by virtual histology-intravascular ultrasound predicts dynamic changes in phenotype and composition of untreated coronary artery lesions.

Background and Aims: We aimed to determine whether finite element analysis (FEA)-derived plaque structural stress (PSS) analysis can predict serial changes in atheroma volume, type, and tissue composition within a fibroatheroma-containing target segment.
Methods: Overall, 210 patients (210 untreated coronary artery lesions) underwent serial (baseline and 12-month follow-up) grayscale- and virtual histology (VH)-intravascular ultrasound (IVUS). Baseline PSS was assessed at the minimal lumen and at the maximum necrotic core (NC) sites.
Results: Overall, there was a significant decrease in %NC volume. The highest PSS tertile was associated with a smaller on-statin reduction in %NC volume (-1.55 ± 1.03% in the highest vs. -5.18 ± 1.12% in the lowest tertile, p = 0.025). Of the 115 lesions with baseline VH-thin cap fibroatheroma (TCFA), 36 (31%) showed persistent VH-TCFA at follow-up. Five of the 95 lesions with baseline thick-cap fibroatheroma evolved into VH-TCFA. Independent predictors of VH-TCFA at follow-up (including persistent and new VH-TCFAs) were diabetes mellitus (odds ratio [OR] = 3.87, 95% CI = 1.58-9.47), a large MLA (OR = 1.39, 95% CI = 1.10-1.75), a greater percent atheroma volume (OR = 1.12, 95% CI = 1.05-1.19), VH-TCFA at baseline (OR = 8.01, 95% CI = 2.73-23.50), and a higher superficial PSS at the maximum NC site (OR = 1.02, 95% CI = 1.00-1.03), (all p < 0.05). Independent determinants of the serial change in %NC volume were high-sensitive C-reactive protein (β = -2.79, 95% CI = -5.31 to -0.27), baseline %NC volume (β = -0.70, 95% CI = -0.84 to -0.56), and superficial PSS at the maximum NC site (β = 0.05, 95% CI = 0.01-0.08), (all p < 0.05).
Conclusions: An elevated PSS was more likely associated with an increase in atheroma volume, a smaller on-statin reduction in %NC volumes, and the presence of VH-TCFA at follow-up. Morphologic and hemodynamic assessment by utilizing VH-IVUS may help understand and predict atherosclerotic progression.
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