A Parametric Evaluation of the Location Dependent Drug Transport Properties of Coronary Arteries

Abstract

Plaque accumulation in the walls of coronary arteries reduces the delivery of nutrients and oxygen to the myocardium. This luminal narrowing can cause clinical indications such as angina or heart attacks, and without treatment, can be fatal. One method of treatment is the percutaneous intervention of stents to re-canalize the vessel. A potential complication of stent implantation is arterial wall remodeling and renarrowing of the vessel; termed restenosis. This can be prevented in the majority of patients with an antiproliferative drug coating on the surface of the stent: a drug-eluting stent. I hypothesize that drug transport in the arterial wall from these devices varies between arterial locations (left anterior descending (LADC) versus right (RC) coronary artery; proximal, middle, versus distal regions). The purpose of this work was to identify the properties of the vascular wall that govern transport, and computationally model stent-based delivery to better understand any differences that could exist in transport based on location. The first aim of this work was to identify the porohyperelastic properties. Permeability showed a decrease along the length of the LADC artery of 198%, and 98.6% along the length of the RC artery (p=NS between LADC and RC). Mechanical properties indicated significant differences between the LADC and RC arteries, with the LADC artery being stiffer than the RC. The second aim of this work was to identify the mass transport and cellular binding properties. There was no difference between the LADC and RC arteries; however, diffusivity peaked in the middle region of both arteries by a factor of 2.07. Convection coupling coefficients indicated an upward trend down each artery with the RC artery having higher values. The third aim was to use the model constants from the previous two aims to create six parametric computational models of stent deployment and drug delivery into the respective arterial sections. Results indicated that RC sections had lower stress along with 2.2 times the species concentration at time points of peak smooth muscle cell migration and remodeling.