Evaluating the Sensitivity of Coronary Artery Hemodynamics to Anatomical Changes in Angles, Branch Positions, and Diameter Ratios

Local hemodynamics play a crucial role in the progression of coronary artery disease [1]. Low wall shear stress (WSS) suggests flow separation and can promote atherosclerotic plaque formation [2]. Computational fluid dynamics studies have explored how anatomy impacts hemodynamics and atherosclerotic risk. However, small sample sizes, idealized geometries, or simplified boundary conditions have limited their scope.

To address these limitations, we quantified hemodynamic sensitivity to changes in bifurcation angles, positions, and diameter ratios in left-coronary arteries (LCA). We implemented an automated workflow in Simvascular to generate synthetic 3D LCA geometries based on data from angiographic studies [3, 4, 5]. The hemodynamic simulations considered rigid arterial walls and used physiological inlet waveforms and specialized coronary outlet conditions. We computed WSS and normalized low WSS areas (ALWSS) at bifurcations and branches in 75 LCA models.

At the proximal LCA bifurcation, position had a more significant effect than angle on ALWSS (R = -0.97, p < 0.0001 v.s. R = -0.62, p < 0.01). Distal ALWSS increased with upstream bifurcation positions (R = -0.78, p < 0.01). Diameter asymmetry at the bifurcation led to higher ALWSS in the smaller branch (p < 0.01).

In conclusion, vascular structure variations had a significant effect on coronary hemodynamics. In particular, proximal bifurcations and high diameter ratios increased ALWSS, potentially indicating greater plaque formation risk.