Computational analysis for competition flows in arteriovenous fistulas based on non-contrast magnetic resonance imaging

TL;DR

This study uses computational simulations based on phase-contrast MRI to classify flow patterns in arteriovenous fistulas, revealing how different flow types impact wall shear stress and pressure, which are crucial for patient outcomes.

Contribution

It introduces a novel classification of flow types around AVF anastomotic sites based on MRI data and analyzes their hemodynamic differences through computational modeling.

Findings

Merging flow type causes spiral flow, high wall shear stress, and large pressure drops.

Splitting flow type results in smooth flow with smaller pressure drops.

Regurgitating flow induces instabilities and high wall shear stress near the anastomotic site.

Abstract

Introduction: Characteristics of hemodynamics strongly affect the patency of arteriovenous fistula (AVF) in hemodialysis patients. Because of pressure balance changes among arteries after AVF construction, regurgitating flow occurs in some patients. Methods: Based on phase-contrast MRI measurements, flow types around the anastomotic site are classified to the three different types of splitting, merging, and one-way, where merging type incorporates regurgitating flow. We have performed computational simulations to analyze characteristic differences among these types. Results: In the merging type, a characteristic spiral flow is observed in AVF causing strong wall shear stress and large pressure drop, whereas the splitting type shows a smooth flow and gives a smaller pressure drop. The one-way case is intermediate between splitting and merging types. Conclusion: Regurgitation brings about high wall shear stress near the anastomotic site because of instabilities induced by merging phenomena, for which type careful follow-up examinations are regarded as necessary.