Investigation of coronary artery tortuosity with atherosclerosis: A study on predicting plaque rupture and progression

This study investigated the effects of different patterns of coronary artery tortuosity (CAT) on the stress concentration of the plaques and the blood flow pattern inside an atherosclerotic artery to predict the risk of plaque rupture and progression. Four different loadings of the coronary artery, including pulsatile blood pressure as well as one-end twist around the artery axis at blood pressures of 74, 100, and 120 mmHg were considered. No study has addressed bent and twist buckling of an atherosclerotic artery considering pulsatile flow (for bent buckling), fluid-solid interaction, and different geometrical parameters of the plaque. The results showed that C-shape tortuosity under pulsatile blood pressure increased the maximum principal stress (MPS) by 10% to 58%, depending on plaque geometry. Application of one end twist, which led to tortuosity in the middle of the artery, increased MPS with rotation angle (e.g., an approximately 2-fold increase was observed for an internal pressure of 74 mmHg). At the moment of maximal transverse deformation, regions of low wall shear stress (WSS < 0.4 Pa) were formed after the tortuosity at the interior wall of the artery, making it prone to the formation of plaque. However, maximum WSS, which occurred at the stenotic region, will make the plaques more prone to rupture. The most influential parameters of plaque geometry on the amount of tortuosity, MPS, and WSS are the stenosis ratio, lipid core angle of 180°, plaque length, and fibrous cap thickness. Furthermore, the effect of mechanical properties of blood on WSS is studied.