Patient-Scale Blood Flow Analysis in Artery Stent Implantation via Smoothed-Particle Hydrodynamics

TL;DR

The paper tackles end-to-end analysis of coronary stent implantation by developing a unified, mesh-free SPH framework that couples weakly compressible hemodynamics with solid-stent mechanics through a multi-resolution discretization. It combines WCSPH with Riemann fluxes, wall boundary handling, Total-Lagrangian solid formulation, and dual-criteria time stepping to efficiently simulate pre- and post-stent hemodynamics, using Windkessel outlets for physiologic boundary conditions. Validation across Poiseuille flow, pressure-driven channel flow, and a three-ring impact demonstrates accuracy and stability, while a patient-specific coronary bifurcation case shows stent deployment reduces resistance and increases FFR from $0.45$ to $0.91$, along with smoother velocity and pressure fields. The work provides a quantitative, clinically interpretable framework for pre-procedural planning and stent design insights, with potential extensions toward fully coupled FSI, non-Newtonian blood models, balloon-expansion modeling, and patient-specific pipelines for broader clinical adoption.

Abstract

A unified Smoothed Particle Hydrodynamics (SPH) simulation framework for coronary stent implantation is developed, which unifies weakly compressible hemodynamics, Neo-Hookean solids, and stent-artery contacts, based on a multi-resolution particle discretization. Prior to application, feasibility and accuracy are established via three baseline validations: (i) poiseuille flow in a two-dimensional channel with prescribed parabolic inflow and a pressure outlet, maintaining parabolic profiles with low Root Mean Squared Error of Prediction (RMSEP); (ii) channel flow initialized with a uniform velocity field and driven by a specified inlet-outlet pressure differential, with agreement to reference profiles quantified by low RMSEP at five reference instants; and (iii) a three-ring impact benchmark in solid mechanics, capturing large deformation, multi-body contact, and self-contact. The validated framework is subsequently applied to a coronary bifurcation with a focal stenosis, where flow-field diagnostics reveal acceleration at the stenotic throat, near-wall low-velocity zones, and co-localization of elevated pressure with increased Von Mises stress at the bifurcation and inlet. Following simulated stent implantation, velocity transitions across the stenosis become smoother, pressure gradients are reduced, and the fractional flow reserve increases from 0.45 to 0.91. These results demonstrate that the proposed SPH framework yields quantitatively reliable, clinically interpretable hemodynamic metrics alongside robust solid-solid contact predictions, thereby supporting rigorous analysis and pre-procedural planning of vascular interventions.

Figures (26)

• Figure 1: Left: anatomical locations of the right and left coronary arteries TexasHeartInstitute. Right: steps of percutaneous stent implantation from guidewire passage and balloon inflation to final stent deployment nhlbi_stent_placement.
• Figure 2: Inter-particle Riemann problem: construction along the $i$–$j$ line (left) and wave structure of the solution (right) zhang2017weakly.
• Figure 3: Wall boundary particles: fluid particles (solid dots) interact with Cartesian dummy particles (hollow) to complete kernel support and impose wall conditions adami2012generalized.
• Figure 4: Comparison of numerical and analytical velocity profiles at different particle spacings.
• Figure 5: Velocity profiles $u(y,t)$ at the five milestones $t_k$. Symbols denote the reference data extracted from Tsugio FukuchiFukuchi2011,solid lines are the present SPH results.