Coupled fluid-chemical computational modeling of anticoagulation therapies in a stented artery

Stent thrombosis is a major complication that occurs after the placement of stents in the coronary artery through balloon angioplasty. The common treatment for stent thrombosis is to provide patients with anticoagulant and antiplatelet therapy through the bloodstream. This study uses numerical modeling to compare two delivery methods of heparin anticoagulant to the arterial wall to reduce thrombus formation: through the flow and via a drug-eluting stent. A unique computational fluid dynamics model is developed that couples an incompressible flow solver with a convection-diffusion-reaction equation solver. The flow solver uses a sharp-interface immersed boundary method on a Cartesian grid to characterize pulsatile flow over the curved wires of the stent. Concurrently, the convection-diffusion-reaction equations are solved for the 19 coupled reactions that make up the coagulation cascade and heparin interactions, as well as reaction and transport equations for both active and inactive platelet species. The simulation is run with input boundary conditions of steady flow, pulsatile Poiseuille flow, and a Womersley flow profile. Results are collected for the bare metal stent case, anticoagulant delivered through the bloodstream, and anticoagulant delivered through a drug-eluting stent. The results generally find that the drugeluting stent delivery of anticoagulant is more effective in reducing platelet activation and clotting, while also providing a more localized anticoagulant distribution.