Validation of a patient-specific hemodynamic computational model for surgical planning of vascular access in hemodialysis patients

Abstract

Caroli, A.; Manini, S.; Antiga, L.; Passera, K.; Ene-Iiordache, B.; Rota, S.; Remuzzi, G.; Bode, A.S.; Leermakers, J.; van de Vosse, F.N.; Vanholder, R.; Malovrh, M.; Tordoir, J.; Remuzzi, A.

Arteriovenous Fistula Development in the First 6 Weeks after Creation

“…The mean AVF vein diameter and blood flow rate increased progressively over 6 weeks, which is similar to findings from other small single-center studies in forearm (1-3,15,16) and upper-arm (17) AVFs. Interestingly, 55% of forearm AVFs and 83% of upper-arm AVFs reached at least 50% of the 6-week blood flow rate measurements at 1 day, which is similar to findings in three small previous studies (4,18,19), only one including upper-arm AVF. Collectively, our large data set and the literature indicate that substantial increases in blood flow and dilation of the vein occur within a day of AVF creation.…”

Novel Paradigms for Dialysis Vascular Access

“…On the basis of demographic and clinical data, it is possible to predict the expected blood flow along the vascular network that will develop with time. We recently reported the results of the validation of this application (63), comparing the calculated vascular access flow with that measured in a group of 63 patients during a follow-up period of 6 weeks. We thus propose using this approach in the clinical routine to perform computer-based planning of AVF surgery using a fast and distributed computer infrastructure (http:/ /avfsim.herokuapp.com).…”

Suppressing unsteady flow in arterio-venous fistulae

“…The parameterisation and constraints were chosen to ensure that the resulting geometry had clinical/anatomical relevance. Specifically, the artery to vein diameter ratio of 1:1 is in line with various measurements made post AVF surgery, 38,68 the maximum venous curvature of 1.8/D a is in line with measurements of maximum curvature in aneurysmatic internal carotid arteries, 69 and the restriction to fit within a cylinder of radius 7.5D a is in line with measurements of average human arm radius. 70 A schematic illustration of the arterial and venous centrelines is shown in Fig.…”

“…This resulted in a Reynolds number of 800 at the PAI and an 80:20 flow split between the DVO and DAO for each configuration. 38,71 Finally, a constant (and arbitrary) pressure was applied at the DVO of each configuration, and a zero-velocity no-slip condition was applied at the arterial and venous walls, which were assumed to be rigid.…”

“…25 More recent work, undertaken specifically in the context of vascular fluid mechanics, includes studies of stenotic flows, 26 pulsatile flow in curved pipes, [27][28][29][30] flow in helical pipes, [31][32][33][34] and flow at junctions. [35][36][37] In terms of simulating flow in AVF configurations, there have been a range of previous Computational Fluid Dynamics (CFD) studies, including 1D simulations, [38][39][40] 2D simulations, 41 3D simulations with rigid walls in idealised geometries, [42][43][44][45][46][47] 3D simulations with rigid walls in more realistic geometries, [48][49][50][51][52][53][54][55] and simulations with distensible walls. 56 Of these studies, several investigated flow unsteadiness.…”