Towards validating stent induced micro flow patterns in left main coronary artery bifurcations

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Fluid Dynamics

Background:

• Stents are crucial in treating coronary artery disease, but their impact on blood flow dynamics requires detailed investigation.
• In vitro models offer a controlled environment to study complex physiological phenomena like blood flow.
• Accurate visualization of micro-scale flow changes is essential for understanding stent performance.

Purpose of the Study:

• To assess the feasibility of using dynamically scaled in vitro 4D Phase-Contrast Magnetic Resonance Imaging (PC-MRI) to detect stent-induced blood flow alterations.
• To compare the efficacy of non-Newtonian and Newtonian fluids in simulating physiological blood flow in scaled arterial geometries.
• To evaluate the influence of patient-specific arterial non-planarity on the detection of near-wall flow changes.

Main Methods:

• 3D printing of idealized and patient-specific left main coronary artery bifurcations.
• In vitro flow circuit with dynamically scaled geometries for 4D PC-MRI acquisition.
• Testing with both non-Newtonian and Newtonian fluids.
• Comparison with true-scale computational fluid dynamics (CFD) simulations.

Main Results:

• The dynamically scaled in vitro PC-MRI setup successfully revealed stent-induced blood flow changes near the vessel wall.
• Non-Newtonian fluid demonstrated strong agreement (R² > 0.9) with CFD simulations, accurately replicating the flow field.
• Newtonian fluid resulted in less prominent fine flow structures compared to non-Newtonian fluid.
• Patient-specific arterial non-planarity posed challenges in capturing subtle near-wall velocity variations.

Conclusions:

• Dynamically scaled in vitro 4D PC-MRI is a promising technique for investigating micro blood flow alterations induced by stents.
• Non-Newtonian fluid behavior is critical for accurate simulation of blood flow in such experimental models.
• Further refinement of the technique is needed to address complexities in patient-specific geometries for comprehensive analysis.