Relationship Between Ascending Thoracic Aortic Aneurysms Hemodynamics and Biomechanical Properties.

OBJECTIVE

Ascending thoracic aortic aneu-rysm (aTAA) is a major cause of human deaths. Despite important recent progress to better understand its pathogenesis and development, the role played by deranged hemodynamics on aTAA risk of rupture is still partially unknown. Our aim was to develop and apply a novel methodology to assess the correlation between aTAA rupture risk and hemodynamic biomarkers combining for the first time in vivo, in vitro, and in silico analyses.

METHODS

Computational fluid dynamic analyses were performed and validated on ten patients using patient-specific data derived from CT scan and four-dimensional MRI. Systolic wall shear stress, time-averaged wall shear stress (TAWSS), flow eccentricity (Flow), and helicity intensity (h) were assessed. A bulge inflation test was carried out in vitro on the ten aTAA samples resected during surgical repair. The biomechanical and rupture properties of these samples were derived: the burst pressure, the physiological tangent elastic modulus (E), the Cauchy stress at rupture (σ), the rupture stretch (λ), and the rupture stretch criterion (Υ). Statistical analysis was performed to determine correlation between all variables.

RESULTS

Statistically highly significant (p < 0.01) positive correlation between λ and the TAWSS (r = 0.867 and p = 0.001) was found.

CONCLUSION

This study shows that relatively low TAWSS significantly correlates with reduced rupture properties in aTAAs.

SIGNIFICANCE

Understanding the pathogenesis of aTAA remains crucial to reduce morbidity and mortality. Our aim is to establish possible correlations between aTAA rupture risk and hemodynamic biomarkers by combining for the first time in vivo, in vitro, and in silico analyses.