Restoration of wall shear stress in the cephalic vein during extreme hemodynamics

Boghosian, Michael; Hammes, Mary; Cassel, Kevin W.; Akherat, S. M. Javid Mahmoudzadeh; Coe, F. L.

doi:10.1080/03091902.2019.1591534

Cited by 6 publications

(5 citation statements)

References 32 publications

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“…This suggests that vessels in older adults are stiffer and less susceptible to intimal hyperplasia. Our hypothesis to explain these findings is based on the adaptation principle, 17 in which vessels of patients of younger age are able to adapt to WSS far better than those of older age because of increased vessel wall stiffness that occurs as we age.…”

Section: Discussionmentioning

confidence: 99%

“…For example, the CFD models are used to demonstrate the principle of adaptation occurring in the cephalic vein. 17 CFD modeling is performed at the time of maturation on the 40 subjects completing the study.…”

Section: Methodsmentioning

confidence: 99%

“…Several critical threshold levels of WSS have been identified in the literature for large arteries and veins. 17 There are at least two existing studies providing the normal physiological range (NPR) for large veins. Malek et al 18 give a range of 0.1 to 0.6 Pa.…”

Section: Normal Physiologic Range For Wss In Large Veinsmentioning

confidence: 99%

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A cohort study showing correspondence of low wall shear stress and cephalic arch stenosis in brachiocephalic arteriovenous fistula access

et al. 2020

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Background: A brachiocephalic fistula is frequently placed for hemodialysis; unfortunately, cephalic arch stenosis commonly develops, leading to failure. We hypothesized that a contribution to brachiocephalic fistula failure is low wall shear stress resulting in neointimal hyperplasia leading to venous stenosis. The objective of this investigation is to determine correspondence of low wall shear stress and the development of cephalic arch stenosis. Methods: Forty subjects receiving hemodialysis with a primary brachiocephalic fistula access were followed from time of placement for 3 years or until cephalic arch stenosis. Venogram, Doppler, and viscosity were performed at time of fistula maturation, annually for 3 years or to time of cephalic arch stenosis. Computational hemodynamics modeling was performed to determine location and percent low wall shear stress in the arch. The relationship between wall shear stress at time of maturation and location of cephalic arch stenosis were estimated by correlating computational modeling and quadrant location of cephalic arch stenosis. Results: In total, 32 subjects developed cephalic arch stenosis with 26 displaying correspondence between location of low wall shear stress at time of maturation and subsequent cephalic arch stenosis, whereas 6 subjects did not (p = 0.0015). Most subjects with correspondence had low wall shear stress areas evident in greater than 20% of the arch (p = 0.0006). Low wall shear stress was associated with a higher risk of cephalic arch stenosis in the 23-to-45 age group (p = 0.0029). Conclusions: The presence and magnitude of low wall shear stress in the cephalic arch is a factor associated with development of cephalic arch stenosis in patients with brachiocephalic fistula. Attenuation of low wall shear stress at time of maturation may help prevent the development of cephalic arch stenosis which is difficult to treat once it develops.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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A cohort study showing correspondence of low wall shear stress and cephalic arch stenosis in brachiocephalic arteriovenous fistula access

et al. 2020

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“…that represent a mature AVF, and another at 12 mo. at which restoration of WSS should occur [31]. The remodeling response in the vein after AVF creation should be greatest in the first 2-6 weeks, during which maturation is achieved.…”

Section: Plos Onementioning

confidence: 99%

Computational modeling of the cephalic arch predicts hemodynamic profiles in patients with brachiocephalic fistula access receiving hemodialysis

et al. 2021

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Background The most common configuration for arteriovenous fistula is brachiocephalic which often develop cephalic arch stenosis leading to the need for numerous procedures to maintain access patency. The hemodynamics that contributes to the development of cephalic arch stenosis is incompletely understood given the inability to accurately determine shear stress in the cephalic arch. In the current investigation our aim was to determine pressure, velocity and wall shear stress profiles in the cephalic arch in 3D using computational modeling as tools to understand stenosis. Methods Five subjects with brachiocephalic fistula access had protocol labs, Doppler, venogram and intravascular ultrasound imaging performed at 3 and 12 months. 3D reconstructions of the cephalic arch were generated by combining intravascular ultrasounds and venograms. Standard finite element analysis software was used to simulate time dependent blood flow in the cephalic arch with velocity, pressure and wall shear stress profiles generated. Results Our models generated from imaging and flow measurements at 3 and 12 months offer snapshots of the patient’s cephalic arch at a precise time point, although the remodeling of the vessel downstream of an arteriovenous fistula in patients undergoing regular dialysis is a dynamic process that persists over long periods of time (~ 5 years). The velocity and pressure increase at the cephalic bend cause abnormal hemodynamics most prominent along the inner wall of the terminal cephalic arch. The topology of the cephalic arch is highly variable between subjects and predictive of pathologic stenosis at later time points. Conclusions Low flow velocity and wall pressure along the inner wall of the bend may provide possible nidus of endothelial activation that leads to stenosis and thrombosis. In addition, 3D modelling of the arch can indicate areas of stenosis that may be missed by venograms alone. Computational modeling reconstructed from 3D radiologic imaging and Doppler flow provides important insights into the hemodynamics of blood flow in arteriovenous fistula. This technique could be used in future studies to determine optimal flow to prevent endothelial damage for patients with arteriovenous fistula access.

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“…Delto-pectoral fascial compression, presence of valves and variable curvature are among the factors that might contribute to the development of CAS [3]. It is also postulated that high flow leads to low wall shear stresses (WSS) with compensatory neointimal hyperplasia and lumen reduction to restore the local WSS [4][5][6]. Other factors may include endothelial damage and proinflammatory, pro-fibrotic mediators [7] with an additive effect of high levels of circulating urea [8].…”

Section: Introductionmentioning

confidence: 99%

Cephalic Arch Stenosis : An Analysis of Outcome by Type of First Intervention

Pisano,

Stevenson,

Kasthuri

et al. 2023

Preprint

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Background Cephalic arch stenoses (CAS) occur in near 70% of elbow arteriovenous fistulas. Percutaneous transluminal angioplasty (PTA) remains first-line treatment despite documented stent-grafts (SG) efficacy. The study aim is to report outcomes based on CAS initial treatment on long-term follow-up. Methods Retrospective review of 12-year data in single tertiary centre. Outcomes included technical success, rupture rate, primary patency (PP), dialysis performance; categorical variables assessed via c2 or Fisher’s; nonparametric tests used for skewed data. Kaplan-Meier analysis used for PP and cumulative patency. Cox proportional hazard regression model to assess explanatory variables in PP. Results 101 brachio- and radiocephalic fistulas with CAS were included. SG as first intervention had higher success than PTA (85% vs 61%, p = 0.003). Rupture occurred in 9/85 (10.6%) PTA vs 0% in SG (p = 0.046). In a subgroup with poor urea reduction rate (URR), both PTA and SG improved dialysis performance post-intervention (p = 0.002). SG demonstrated better PP than PTA (79,73,60% patency at 3, 6, 9 months; versus 71,51,47%; p = 0.195) and cumulative patency (73,61,61% at 1, 2, 3 years; versus 60,34,26%; p < 0.001). Of the variables analyzed, technical success of PTA was the only discriminating factor (coeff.-1.01; RR 35%,p = 0.035). Accesses that underwent secondary stenting performed better than primarily stented CAS (p = 0.01). Conclusions: SG superiority is confirmed in CAS, particularly when angioplasty is unsuccessful. While PTA has short-lived benefits, it can improve dialysis performance. Other than higher success rate, primary CAS stenting did not have advantages compared to post-PTA stenting in our study. Other factors related to inflow, outflow, conduit characteristics are presumed to be involved in access longevity.

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Restoration of wall shear stress in the cephalic vein during extreme hemodynamics

Cited by 6 publications

References 32 publications

A cohort study showing correspondence of low wall shear stress and cephalic arch stenosis in brachiocephalic arteriovenous fistula access

A cohort study showing correspondence of low wall shear stress and cephalic arch stenosis in brachiocephalic arteriovenous fistula access

Computational modeling of the cephalic arch predicts hemodynamic profiles in patients with brachiocephalic fistula access receiving hemodialysis

Cephalic Arch Stenosis : An Analysis of Outcome by Type of First Intervention

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