Hemodynamics in the cephalic arch of a brachiocephalic fistula

Abstract

The care and outcome of patients with end stage renal disease (ESRD) on chronic hemodialysis is directly dependent on their hemodialysis access. A brachiocephalic fistula (BCF) is commonly placed in the elderly and in patients with a failed lower-arm, or radiocephalic, fistula. However, there are numerous complications such that the BCF has an average patency of only 3.6 years. A leading cause of BCF dysfunction and failure is stenosis in the arch of the cephalic vein near its junction with the axillary vein, which is called cephalic arch stenosis (CAS). Using a combined clinical and computational investigation, we seek to improve our understanding of the cause of CAS, and to develop a means of predicting CAS risk in patients with a planned BCF access. This paper details the methodology used to determine the hemodynamic consequences of the post-fistula environment and illustrates detailed results for a representative sample of patient-specific anatomies, including a single, bifurcated, and trifurcated arch. It is found that the high flows present due to fistula creation lead to secondary flows in the arch owing to its curvature with corresponding low wall shear stresses. The abnormally low wall shear stress locations correlate with the development of stenosis in the singular case that is tracked in time for a period of one year.

Are Non-Newtonian Effects Important in Hemodynamic Simulations of Patients With Autogenous Fistula?

“…As mentioned before, from a clinical point of view, the WSS is the primary hemodynamic quantity of interest in this work. In the literature, the homeostatic range of WSS in the "human cephalic vein" is reported to be between 0.076 and 0.76 Pa [4,25,30,37,39]. In a parallel study [40], we substantiated these values for the cephalic vein in the present patient cohort via an integrated clinical, computational, and statistical investigation.…”

“…Patient-specific venograms and Doppler velocimetry are performed simultaneously by an interventional radiologist and are used to reconstruct the geometries and inlet velocity profiles, respectively [30,37]. In Figs.…”

Increased Inlet Blood Flow Velocity Predicts Low Wall Shear Stress in the Cephalic Arch of Patients with Brachiocephalic Fistula Access

“…A computational model of the hemodynamics through the cephalic vein and arch was created from the measured Doppler BFV, blood viscosity, and venogram image. This methodology has been used in previous research to predict various hemodynamic parameters such as velocity, pressure, and WSS throughout the vessel as shown in Boghosian et al [ 19 ]. In the present investigation, two-dimensional simulations are carried out with and without pulsatility in order to determine its effect on the percent low WSS within the cephalic arch region.…”

Hemodynamic and Biologic Determinates of Arteriovenous Fistula Outcomes in Renal Failure Patients

“…Anastomotic design and strategies and devices to define optimal WSS are in the process of being developed [ 47 ]. Computational models have been developed and are able to predict the clinical relevance of WSS in predicting AVF maturation and venous stenosis [ 48 – 50 ]. Randomized clinical trials are needed to determine the utility of CFD to improve AVF outcomes.…”