Fluid-structure interaction simulations in patient-specific coronary arteries with aneurysms: Viscoelastic or...

Coronary artery aneurysm is a progressive and often asymptomatic condition with a prevalence ranging from 0.3 % to 5 %. This condition can lead to severe and potentially fatal complications. Given the challenges of conducting experiments on real patients, numerical simulations have emerged as a valuable alternative. This study aims to enhance the accuracy of hemodynamic analysis and fluid-structure interaction assessments by incorporating the viscoelastic properties of blood, which are often overlooked, in simulations of the right coronary artery with various aneurysm morphologies.

This research employs numerical simulations to analyse the hemodynamics and assess the one-way coupled fluid-structure interaction within the right coronary artery. The study utilised the simplified Phan-Thien/Tanner model to represent the viscoelastic properties of blood. Different aneurysm morphologies were simulated, and the results were compared with those obtained using the widely recognised Carreau model. The analysis focused on the time-average wall-shear stress, as well as the stress and deformation experienced by the aneurysm wall.

The hemodynamic analysis demonstrated that the simplified Phan-Thien/Tanner model produced similar flow patterns to the Carreau model but resulted in a significant reduction of approximately 50 % in the time-average wall-shear stress. This reduction aligns with previous findings. Additionally, the study revealed substantial differences in the stress and deformation of the aneurysm wall, with the simplified Phan-Thien/Tanner model proving more accuracy. The largest deformations were observed in aneurysms with incipient and fusiform shapes, particularly in the divergent section of the proximal region. In the case of saccular aneurysms, the most compromised area was identified not within the aneurysm sac itself, but in the region of the artery just upstream.

Incorporating the viscoelastic properties of blood into fluid-structure interaction simulations significantly improves the accuracy of hemodynamic and structural assessments of coronary artery aneurysms. This study underscores the importance of considering these properties when evaluating aneurysm behaviour, which could have important implications for understanding the progression and potential rupture of aneurysms, thereby guiding more effective clinical interventions.