Effects of diffusion coefficients and struts apposition using numerical simulations for drug eluting coronary stents.
In the context of drug eluting stent, we present two-dimensional numerical models of mass transport of the drug in the wall and in the lumen to study the effect of the drug diffusion coefficients in the three principal media (blood, vascular wall, and polymer coating treated as a three-compartment problem) and the impact of different strut apposition configurations (fully embedded, half embedded, and not embedded). The different conditions were analyzed in terms of their consequence on the drug concentration distribution in the arterial wall. We apply the concept of the therapeutic window to the targeted vascular wall region and derive simple metrics to assess the efficiency of the various stent configurations. Although most of the drug is dispersed in the lumen, variations in the blood flow rate within the physiological range of coronary blood flow and the diffusivity of the drug molecule in the blood were shown to have a negligible effect on the amount of drug in the wall. Our results reveal that the amount of drug cumulated in the wall depends essentially on the relative values of the diffusion coefficients in the polymer coating and in the wall. Concerning the strut apposition, it is shown that the fully embedded strut configuration would provide a better concentration distribution.
Mongrain
Rosaire
R
Department of Mechanical Engineering, McGill University, Montreal, Quebec H3A 2K6, Canada. rosaire.mongrain@mcgill.ca
Faik
Isam
I
Leask
Richard L
RL
Rodés-Cabau
Josep
J
Larose
Eric
E
Bertrand
Olivier F
OF
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D001158:Arteries / Q000378:metabolism / Q000502:physiology; D001783:Blood Flow Velocity; D002317:Cardiovascular Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003198:Computer Simulation; D004058:Diffusion; D054855:Drug-Eluting Stents; D005343:Fibrinolytic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D018056:Hemorheology; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D012039:Regional Blood Flow
D000893:Anti-Inflammatory Agents; D002317:Cardiovascular Agents; D005343:Fibrinolytic Agents; D007166:Immunosuppressive Agents