Serial analysis of lumen geometry and hemodynamics in human arteriovenous fistula for hemodialysis using magnetic resonance imaging and computational fluid dynamics

Abstract

The arteriovenous fistula (AVF) is the preferred form of vascular access for maintenance hemodialysis, but it often fails to mature to become clinically usable, likely due to aberrant hemodynamic forces. A robust pipeline for serial assessment of hemodynamic parameters and subsequent lumen cross-sectional area changes has been developed and applied to a data set from contrast-free MRI of a dialysis patient’s AVF collected over a period of months after AVF creation surgery. Black-blood MRI yielded images of AVF lumen geometry, while cine phase-contrast MRI provided volumetric flow rates at the in-flow and out-flow locations. Lumen geometry and flow rates were used as inputs for computational fluid dynamic (CFD) modeling to provide serial wall shear stress (WSS), WSS gradient, and oscillatory shear index profiles. The serial AVF lumen geometries were co-registered at 1-mm intervals using respective lumen centerlines, with the anastomosis as an anatomical landmark. Lumen enlargement was limited at the vein region near the anastomosis and a downstream vein valve, potentially attributed to a physical inhibition of wall expansion at those sites. This work is the first serial and detail study of lumen and hemodynamic changes in human AVF using MRI and CFD. This novel protocol will be used for a multicenter prospective study to identify critical hemodynamic factors that contribute to AVF maturation failure.

New Insights into Dialysis Vascular Access: Molecular Targets in Arteriovenous Fistula and Arteriovenous Graft Failure and Their Potential to Improve Vascular Access Outcomes

“…Magnetic resonance imaging and computed tomography have been used in both large-animal and clinical studies to evaluate neointimal hyperplasia development, lumen geometry, hemodynamics, and computational fluid dynamics (34,(64)(65)(66). These imaging technologies would be even more powerful if they could be applied in transgenic rodent models where the combination of pathobiology and computational fluid dynamics modeling could be studied in greater depth.…”

Novel Paradigms for Dialysis Vascular Access

“…The next step in these investigations should be the use of image-based CFD analyses to document WSS patterns in patient-specific models of AVF during vascular access follow-up (58,59), aimed at identifying areas at risk for development of neointimal hyperplasia. Moreover, with the advent of parallel processors power and new CFD solvers including fluid-structure interaction, vessel wall elasticity could be modeled in pulsatile simulations toward the understanding of the influence of wall compliance on the pattern of disturbed flow in AVF.…”

Hemodynamic Shear Stress and Endothelial Dysfunction in Hemodialysis Access

“…He et al developed an MRI-CFD protocol that uses state-of-the-art techniques to characterize blood flow and calculate WSS in human AVF (Figure 2) [46]; this protocol has also been used in AVG [67]. The protocol by He et al uses contrast-free MRI, black blood MRI for lumen geometry and cine phase-contrast MRI for flow measurement.…”

“…In Misra et al [43], WSS in the porcine model was also obtained by estimation from Poiseuille’s law using velocity measured at discrete 2D slices using cine phase-contrast MRI and luminal area obtained by 3D magnetic resonance angiography and histology. We have used the MRI-CFD approach by He et al mentioned above [46] to characterize WSS in a porcine AVG in a more comprehensive manner [67]. …”

“…Reprinted from Journal of Biomechanics , Y He, C Terry, C Nguyen, S Berceli, Y Shiu, A Cheung, “Serial analysis of lumen geometry and hemodynamics in human arteriovenous fistula for hemodialysis using magnetic resonance imaging and computational fluid dynamics,” 46:165–169. Copyright (2013), with permission from Elsevier [46]. …”