Recurrent thrombosis and patency of the arteriovenous access in patients receiving hemodialysis.

Background: Thrombosis of the vascular access in patients with end-stage renal disease requiring hemodialysis are common and require timely interventional procedures to restore patency. The aim of the current study was to identify factors having a significant effect on patency rates after access thrombosis. Our hypothesis was the length of time between the initial clotting of the access and the subsequent percutaneous declotting impacts the patency rates of the vascular access.

Acute Kidney Injury in Coronavirus Disease and Association with Thrombosis.

Introduction: Coronavirus disease (COVID-19) is a global pandemic which continues to cause systemic inflammation, leading to multi-system organ damage including acute kidney injury (AKI) and thrombotic complications. We hypothesize that D-dimer level predicts an increased risk of AKI and thrombotic complications in COVID-19.

Methods: This was a retrospective cohort study performed at a single-center academic center.

Creating patient-specific vein models to characterize wall shear stress in hemodialysis population.

End-Stage Renal Disease (ESRD) patients require arteriovenous fistulas (AVF) that allow a mature vein to withstand hemodialysis. Unfortunately, venous thrombosis and stenosis in the cephalic vein arch after AVF placement is common and heavily influenced by hemodynamics. To better assess forces and flow behavior in the cephalic arch, we have built patient-specific millifluidic models that allow us to explore the complex interplay between patient-specific vein geometry and fluctuating hemodynamics.

The FACT : Use of a novel intermittent pneumatic compression device to promote pre-surgery arm vein dilation in patients with chronic renal failure.

Background: Arteriovenous fistula (AVF) creation and maturation for hemodialysis is globally a topic of importance given the poor results and high costs associated with renal care. Successful AVF (surgical or endovascular) creation requires appropriate superficial veins and quality arteries. Many procedures fail due to initial small veins with limited blood flow capacity and distensibility.

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

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.

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

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.

Outcomes After Percutaneous Angioplasty of Arteriovenous Fistulas and Grafts in African American Patients.

Purpose: Arteriovenous fistulas and grafts, necessary for hemodialysis, may develop stenoses due to neointimal hyperplasia, which often require percutaneous transluminal angioplasty. Patient and lesion characteristics were evaluated prior to angioplasty and were correlated with 1- and 6-month outcomes.

Materials And Methods: This was an observational study of African American hemodialysis patients who presented for angioplasty of a dysfunctional fistula or graft.

Use of Hepatitis C Positive Organs: Patient Attitudes in Urban Chicago.

Background: Hepatitis C virus (HCV)-infected organs are being transplanted in patients with and without HCV in the direct-acting antiviral era. Little is known about patient attitudes towards receiving an HCV-positive organ.

Objectives: The aim of this study is to determine transplant candidates' attitudes towards receiving HCV-positive organs.

Hemodynamic effects of hemodialyzer pump speed on arteriovenous fistulas .

Aim: Arteriovenous fistulas (AVF) are the optimal vascular access for hemodialysis although many fistulas fail. The impetus to increase hemodialyzer blood flow (QB) in order to maximize solute clearances may be counterbalanced if AVF suffer adverse hemodynamic effects from accelerated pump flows. The optimal QB to maintain adequate hemodialysis without potentially contributing to AVF dysfunction is unknown.

A Report of Two Cases of Hazards Associated with High Flow Arteriovenous Fistula in ESRD Patients.

High flow arteriovenous fistulas are a common clinical entity affecting patients with end-stage renal failure receiving hemodialysis. Given the difficulty in predicting who will develop a high flow arteriovenous fistula the exact prevalence is unclear. We present two cases of patients with high flow arteriovenous fistula that developed clinical cardiac failure at a time point after the fistula was placed with findings of significant cephalic arch stenosis.

Asymmetric Dimethylarginine does not Predict Early Access Events in Hemodialysis Patients with Brachiocephalic Fistula Access.

Background: Vascular access for hemodialysis is best provided by an arteriovenous fistula (AVF). AVF fail primarily because of neointimal hyperplasia. Asymmetric dimethlyarginine (ADMA) is a naturally occurring analogue of L-arginine, which is elevated in renal failure and impairs endothelial cell function.

A Predictive Framework to Elucidate Venous Stenosis: CFD & Shape Optimization.

The surgical creation of vascular accesses for renal failure patients provides an abnormally high flow rate conduit in the patient's upper arm vasculature that facilitates the hemodialysis treatment. These vascular accesses, however, are very often associated with complications that lead to access failure and thrombotic incidents, mainly due to excessive neointimal hyperplasia (NH) and subsequently stenosis. Development of a framework to monitor and predict the evolution of the venous system post access creation can greatly contribute to maintaining access patency.

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

Given the current emphasis on accurate computational fluid dynamics (CFD) modeling of cardiovascular flows, which incorporates realistic blood vessel geometries and cardiac waveforms, it is necessary to revisit the conventional wisdom regarding the influences of non-Newtonian effects. In this study, patient-specific reconstructed 3D geometries, whole blood viscosity data, and venous pulses postdialysis access surgery are used as the basis for the hemodynamic simulations of renal failure patients with native fistula access. Rheological analysis of the viscometry data initially suggested that the correct choice of constitutive relations to capture the non-Newtonian behavior of blood is important because the end-stage renal disease (ESRD) patient cohort under observation experience drastic variations in hematocrit (Hct) levels and whole blood viscosity throughout the hemodialysis treatment.

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

Background: An autogenous arteriovenous fistula is the optimal vascular access for hemodialysis. In the case of brachiocephalic fistula, cephalic arch stenosis commonly develops leading to access failure. We have hypothesized that a contribution to fistula failure is low wall shear stress resulting from post-fistula creation hemodynamic changes that occur in the cephalic arch.

Hemodynamic and biologic determinates of arteriovenous fistula outcomes in renal failure patients.

The outcome of patients with end-stage renal disease on hemodialysis depends on a functioning vascular access. Although a variety of access options are available, the arteriovenous fistula remains the best vascular access. Unfortunately the success rate of mature fistula use remains poor.

Central venous catheters: incidence and predictive factors of venous thrombosis.

Aims: Central venous catheter access in an acute setting can be a challenge given underlying disease and risk for venous thrombosis. Peripherally inserted central venous catheters (PICCs) are commonly placed but limit sites for fistula creation in patients with chronic renal failure (CKD). The aim of this study is to determine the incidence of venous thrombosis from small bore internal jugular (SBIJ) and PICC line placement.

Morphometric and histological parameters in veins of diabetic patients undergoing brachiocephalic fistula placement.

Diabetic patients with end-stage renal failure have higher rates of arteriovenous failures when compared with nondiabetics. The aim was to compare differences in indicators of vascular remodeling and endothelial dysfunction in veins of patients with or without diabetes at the time of surgical placement. In this prospective observational trial, vein samples were collected from patients when a brachiocephalic fistula was created.

Characterization of the cephalic arch and location of stenosis.

Purpose: The purpose of this study is to accurately characterize the cephalic arch segments into four domains and to enable more specific evaluation of cephalic arch stenosis (CAS) and determine the frequency of stenosis in each domain.

Methods: After Institutional Review Board (IRB) approval, a retrospective chart review was done to define a population of patients receiving hemodialysis who developed CAS as apparent on clinically indicated radiologic imaging. A standardized approach was devised to categorize four domains of the cephalic arch.

Asymmetric dimethylarginine and whole blood viscosity in renal failure.

Background: Renal failure is a disease with accelerated atherosclerosis beginning with endothelial cell dysfunction. Factors affecting endothelial cell dysfunction include whole blood viscosity (WBV) and asymmetric dimethylarginine (ADMA). The relationship in controls and renal failure was determined.

Whole blood viscosity: Effect of hemodialysis treatment and implications for access patency and vascular disease.

Background: Hemodialysis patients have increased mortality from cardiovascular complications. Whole blood viscosity (WBV) and red cell aggregation (RCA) may influence the pathogenesis of vascular complications in this population. The objective of this study was to determine whether the hemodialysis treatment or vascular complications were associated with impaired WBV or RCA.

Characteristic differences in cephalic arch geometry for diabetic and non-diabetic ESRD patients.

Background: Fistula access in chronic haemodialysis patients is recommended. The first and second choice for location of fistula placement is radial-cephalic followed by the brachiocephalic fistula. Fistula access using the cephalic vein often results in cephalic arch stenosis that is less common in diabetics for unclear reasons.