Incomplete Restoration of Homeostatic Shear Stress Within Arteriovenous Fistulae

2012 ◽  
Author(s):  
Patrick M. McGah ◽  
James J. Riley ◽  
Alberto Aliseda ◽  
Daniel F. Leotta ◽  
Kirk W. Beach
Keyword(s):  
Shear Stress ◽  
Peripheral Circulation ◽  
Shear Stresses ◽  
Dialysis Access ◽  
Venous Flow ◽  
Arteriovenous Fistulae ◽  
Flow Rates ◽  
Stage Renal Disease ◽  
End Stage ◽  
Low Shear

Arteriovenous fistulae are created surgically to provide an adequate access for dialysis in patients with End-Stage Renal Disease (ESRD). Producing an autogenous shunt linking an artery and a vein in the peripheral circulation bypasses the high resistance capillary bed in order to provide the necessary flow rates at sites easily accessible for dialysis. In successful fistulae, venous flow rates can easily exceed 1000 mL/min. It has long been recognized that the hemodynamics constitute the primary external influence on the remodeling process [1]; The high flow rate, together with the exposure of the venous tissue to the high arterial pressure, leads to a rapid process of wall remodeling that may end in a mature access or in failure. Recent hemodynamic simulations [2,3] have computed very high viscous wall shear stresses within fistulae; Stresses > 15Pa have been reported which are much greater than what is typically considered normal (i.e. homeostatic, ≈ 1Pa). Both sustained high shear and sustained low shear have been hypothesized to cause pathological venous remodeling (i.e. intimal hyperplasia) which causes stenoses and threatens fistula patency. The role of high vs. low shear stress in effecting patency remains unclear. Given the high failure rate of dialysis access sites (up to 50% require surgical revision within one year [4]), understanding the dynamics of blood flow within the fistula is a necessary step in understanding the remodeling, and ultimately, in improving clinical outcomes.

Hemodynamic Comparisons Between Different Anastomotic Configurations in Dialysis Access Fistulae

2011 ◽  
Author(s):  
Patrick M. McGah ◽  
Alberto Aliseda ◽  
James J. Riley ◽  
Daniel F. Leotta ◽  
Kirk W. Beach
Keyword(s):  
Peripheral Circulation ◽  
Dialysis Access ◽  
External Influence ◽  
High Failure Rate ◽  
Venous Flow ◽  
Flow Rates ◽  
Capillary Bed ◽  
One Year ◽  
Stage Renal Disease ◽  
End Stage

Arteriovenous fistulae are created surgically to provide an adequate access for dialysis in patients with End-Stage Renal Disease. Producing an autogenous shunt linking an artery and a vein in the peripheral circulation bypasses the high resistance capillary bed in order to provide the necessary flow rates at sites easily accessible for dialysis. In successful fistulae, venous flow rates can easily exceed 1000 mL/min. It has long been recognized that the hemodynamics constitute the primary external influence on the remodeling process [1, 2]; The high flow rate, together with the exposure of the venous tissue to the high arterial pressure, leads to a rapid process of wall remodeling that may end in a mature access or in stenosis and failure. Given the high failure rate of dialysis access (up to 50% require surgical revision within one year [3]), understanding the dynamics of blood flow within the fistula is a necessary step in understanding the remodeling, and ultimately, in improving clinical outcomes.

Effects of Wall Distensibility on the Numerical Simulation of Arteriovenous Fistulae

2013 ◽  
Author(s):  
Patrick M. McGah ◽  
Alberto Aliseda ◽  
Daniel F. Leotta ◽  
Kirk W. Beach
Keyword(s):  
Vascular Tissue ◽  
Peripheral Circulation ◽  
Shear Stresses ◽  
Dialysis Access ◽  
Arteriovenous Fistulae ◽  
Capillary Bed ◽  
One Year ◽  
Stage Renal Disease ◽  
End Stage ◽  
Hemodynamic Simulations

Arteriovenous fistulae are created surgically to provide an adequate access for dialysis in patients with End-Stage Renal Disease (ESRD). Producing an autogenous shunt linking an artery and a vein in the peripheral circulation bypasses the high resistance capillary bed in order to provide the necessary flow rates at sites easily accessible for dialysis. It has long been recognized that hemodynamics constitute the primary external influence on the remodeling process of anastomosed vascular tissue [1, 2]. The high flow rate, together with the exposure of the venous tissue to the high arterial pressure, leads to a rapid process of wall remodeling that may lead to a mature access or end in failure. Recent hemodynamic simulations [3, 4] have computed very high viscous wall shear stresses within dialysis access fistulae; Stresses >15 Pa have been reported. These are much higher than what is typically considered normal or homeostatic (i.e. ≈ 1–1.5 Pa). The abnormal stresses in the fistulae have been hypothesized to cause pathological venous remodeling (i.e. intimal hyperplasia) which causes stenoses and threatens fistula patency. Given the high failure rate of dialysis access sites (up to 50% require surgical revision within one year), understanding the dynamics of blood flow within the fistula is a necessary step in understanding remodeling, and ultimately, in improving clinical outcomes.

scholarly journals Incomplete Restoration of Homeostatic Shear Stress Within Arteriovenous Fistulae

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Patrick M. McGah ◽  
Daniel F. Leotta ◽  
Kirk W. Beach ◽  
R. Eugene Zierler ◽  
Alberto Aliseda
Keyword(s):  
3D Ultrasound ◽  
Patient Specific ◽  
Shear Stresses ◽  
Arteriovenous Fistulae ◽  
Vessel Remodeling ◽  
Mechanical Homeostasis ◽  
Stage Renal Disease ◽  
End Stage ◽  
Hemodynamic Simulations

Arteriovenous fistulae are surgically created to provide adequate access for dialysis patients suffering from end-stage renal disease. It has long been hypothesized that the rapid blood vessel remodeling occurring after fistula creation is, in part, a process to restore the mechanical stresses to some preferred level, i.e., mechanical homeostasis. We present computational hemodynamic simulations in four patient-specific models of mature arteriovenous fistulae reconstructed from 3D ultrasound scans. Our results suggest that these mature fistulae have remodeled to return to ‘‘normal’’ shear stresses away from the anastomoses: about 1.0 Pa in the outflow veins and about 2.5 Pa in the inflow arteries. Large parts of the anastomoses were found to be under very high shear stresses >15 Pa, over most of the cardiac cycle. These results suggest that the remodeling process works toward restoring mechanical homeostasis in the fistulae, but that the process is limited or incomplete, even in mature fistulae, as evidenced by the elevated shear at or near the anastomoses. Based on the long term clinical viability of these dialysis accesses, we hypothesize that the elevated nonhomeostatic shear stresses in some portions of the vessels were not detrimental to fistula patency.

scholarly journals Distal Radial Artery Ligation for Dialysis Access Steal Syndrome

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
David Fung ◽  
Yaasin Abdulrehman
Keyword(s):  
Radial Artery ◽  
Surgical Techniques ◽  
Limb Ischemia ◽  
Definitive Treatment ◽  
Dialysis Access ◽  
Artery Ligation ◽  
Stage Renal Disease ◽  
End Stage ◽  
Steal Syndrome ◽  
Distal Radial Artery

Renal replacement therapy is the definitive treatment for end stage renal disease apart from transplant. Steal syndrome, which can lead to distal limb ischemia, is a rare but serious complication in patients who undergo hemodialysis with an arteriovenous fistula. We present a case of a 48-year-old female with limited options for dialysis access who presented with symptoms of steal syndrome. Given the need to keep her current fistula, we opted to treat her with distal radial artery ligation. This case report summarizes the various surgical techniques available for treating dialysis access-associated steal syndrome and why distal radial artery ligation should be considered a viable management strategy, especially in the context of our patient.

Clinical Considerations in Hemodialysis Access Intervention

2018 ◽  
pp. 594-614
Author(s):  
Eric K. Hoffer
Keyword(s):  
Renal Disease ◽  
Arteriovenous Fistula ◽  
End Stage Renal Disease ◽  
Morbidity And Mortality ◽  
Dialysis Access ◽  
Hemodialysis Access ◽  
National Kidney Foundation ◽  
Clinical Considerations ◽  
Stage Renal Disease ◽  
End Stage

Interventional radiologists developed and refined the endovascular approaches to maintenance of the permanent arteriovenous vascular accesses that are integral to the provision of hemodialysis for patients with end stage renal disease. As methods of percutaneous arteriovenous fistula creation expand the scope of IR, this chapter reviews the clinical indications and preferences pertinent to dialysis access creation with respect to National Kidney Foundation Recommendations. Accesses remain imperfect, plagued by the development of flow-limiting intimal hyperplastic stenoses, and require monitoring and maintenance to minimize complications, morbidity and mortality. The measures of dialysis access function used in the surveillance of vascular accesses that indicate potential stenosis, and the utility of pre-occlusion recanalization of these stenoses are discussed. Complications specific to dialysis access interventions are also addressed.

scholarly journals Bioengineered human acellular vessels for dialysis access in patients with end-stage renal disease: two phase 2 single-arm trials

The Lancet ◽  
2016 ◽  
Vol 387 (10032) ◽  
pp. 2026-2034 ◽  
Author(s):  
Jeffrey H Lawson ◽  
Marc H Glickman ◽  
Marek Ilzecki ◽  
Tomasz Jakimowicz ◽  
Andrzej Jaroszynski ◽  
...  
Keyword(s):  
Renal Disease ◽  
End Stage Renal Disease ◽  
Dialysis Access ◽  
Phase 2 ◽  
Two Phase ◽  
Stage Renal Disease ◽  
End Stage

Cost analysis of ongoing care of patients with end-stage renal disease: The impact of dialysis modality and dialysis access

2002 ◽  
Vol 40 (3) ◽  
pp. 611-622 ◽  
Author(s):  
Helen Lee ◽  
Braden Manns ◽  
Ken Taub ◽  
William A. Ghali ◽  
Stafford Dean ◽  
...  
Keyword(s):  
Cost Analysis ◽  
Renal Disease ◽  
End Stage Renal Disease ◽  
Dialysis Access ◽  
Dialysis Modality ◽  
Ongoing Care ◽  
Stage Renal Disease ◽  
End Stage ◽  
The Impact

scholarly journals In Vivo Shear Stress Determines Circulating Levels of Endothelial Microparticles in End-Stage Renal Disease

Hypertension ◽  
2007 ◽  
Vol 49 (4) ◽  
pp. 902-908 ◽  
Author(s):  
Chantal M. Boulanger ◽  
Nicolas Amabile ◽  
Alain P. Guérin ◽  
Bruno Pannier ◽  
Aurélie S. Leroyer ◽  
...  
Keyword(s):  
Shear Stress ◽  
Renal Disease ◽  
End Stage Renal Disease ◽  
Endothelial Microparticles ◽  
Stage Renal Disease ◽  
End Stage ◽  
Circulating Levels

Dialysis access: issues related to conversion from peritoneal dialysis to hemodialysis and vice versa

2017 ◽  
Vol 18 (1_suppl) ◽  
pp. S41-S46 ◽  
Author(s):  
Maurizio Gallieni ◽  
Antonino Giordano ◽  
Anna Ricchiuto ◽  
Davide Gobatti ◽  
Maurizio Cariati
Keyword(s):  
Peritoneal Dialysis ◽  
End Stage Renal Disease ◽  
Venous Catheter ◽  
Infectious Complications ◽  
Dialysis Access ◽  
Central Venous ◽  
Treatment Start ◽  
Alternative Approach ◽  
Stage Renal Disease ◽  
End Stage

Hemodialysis (HD) and peritoneal dialysis (PD) represent two complementary modalities of renal replacement therapy (RRT) for end-stage renal disease patients. Conversion between the two modalities is frequent and more likely to happen from PD to HD. Every year, 10% of PD patients convert to HD, suggesting the need for recommendations on how to proceed with the creation of a vascular access in these patients. Criteria for selecting patients who would likely fail PD, and therefore take advantage of a backup access, are undefined. Creating backup fistulas at the time of PD treatment start to allow emergency access for HD has proved to be inefficient, but it may be considered in patients with progressive difficulty in achieving adequate depuration and/or peritoneal ultrafiltration. A big challenge is represented by patients switching from PD to HD for unexpected infectious complications. Those patients need to start HD with a central venous catheter (CVC), but an alternative approach might be using an early cannulation graft, provided that infection has been cleared by the circulation. An early cannulation graft might also be used to considerably shorten the time spent using a CVC. In patients who need a conversion from HD to PD, urgent-start PD is now an accepted and well-established approach.

scholarly journals The effect to flow rate characteristic on biodegradation of bone scaffold

2017 ◽  
Vol 13 (4-2) ◽  
pp. 546-552 ◽  
Author(s):  
Hasan Basri ◽  
Jimmy Deswidawansyah Nasution ◽  
Ardiyansyah Syahrom ◽  
Mohd Ayub Sulong ◽  
Amir Putra Md. Saad ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Computational Models ◽  
Shear Stresses ◽  
Experimental Conditions ◽  
Flow Rates ◽  
Pressure Drops ◽  
Bone Scaffolds ◽  
Wall Shear

This paper proposes an improved modeling approach for bone scaffolds biodegradation. In this study, the numerical analysis procedure and computer-based simulation were performed for the bone scaffolds with varying porosities in determining the wall shear stresses and the permeabilities along with their influences on the scaffolds biodegradation process while the bio-fluids flow through within followed with the change in the flow rates. Based on the experimental study by immersion testing from 0 to 72 hours of the time period, the specimens with different morphologies of the commercial bone scaffolds were collected into three groups samples of 30%, 41%, and 55% porosities. As the representative of the cancellous bone morphology, the morphological degradation was observed by using 3-D CAD scaffold models based on microcomputed tomography images. By applying the boundary conditions to the computational fluid dynamics (CFD) and the fluid-structure interaction (FSI) models, the wall shear stresses within the scaffolds due to fluid flow rates variation had been simulated and determined before and after degradation. The increase of fluid flow rates tends to raise the pressure drop for scaffold models with porosities lower than 50% before degradation. As the porosities increases, the pressure drop decreases with an increase in permeability within the scaffold. The flow rates have significant effects on scaffolds with higher pressure drops by introducing the wall shear stresses with the highest values and lower permeability. These findings indicate the importance of using accurate computational models to estimate shear stress and determine experimental conditions in perfusion bioreactors for tissue engineering more accurate results will be achieved to indicate the natural distributions of fluid flow velocity, wall shear stress, and pressure.

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