Multi-Parametric Computational Investigation of Stent Design for Tortuous Coronary Artery Bifurcations

Our work aims to investigate the effect of individual branch tortuosities on the atherosclerotic susceptibility at the left main coronary bifurcation, and further investigate parameters related to the design of coronary stents in order to best suit the requirements of such arteries.

The bend angle has been used as the metric for tortuosity, being varied between a physiological range of 15 and 60 degrees for each branch, while keeping the other two branches unchanged. Idealized geometries of the left coronary artery have been analyzed, and the impact of the stent design parameters strut spacing and lumen protrusion on the hemodynamics of the vessel for both straight and tortuous arteries studied, using CFD.

Our results indicate that the LAD branch is most significantly impacted by a change in the curvature of either of the branches and may hence be said to be most susceptible to the formation of atherosclerotic lesions. The OSI is observed to be impacted only in the curved branch. In general, an increase in tortuosity is associated with an up to 13% increase in the average TAWSS.

An increase in the strut spacing is observed to be associated with improved hemodynamics at the coronary bifurcation. The introduction of a stent in the LM branch is observed to have an ameliorating impact on the hemodynamics of the LAD branch, with an up to 23% reduction in adverse TAWSS regions being observed with an increase in strut spacing. Additionally, greater lumen protrusion increases both adverse TAWSS (max. 15%) and adverse RRT (max. 18%) regions.