An immediate access dialysis graft designed to prevent needle-related complications: Results from the initial pre-clinical studies

Early cannulation arteriovenous graft (Acuseal) versus standard arteriovenous graft in patients with end-stage renal disease

INTRODUCTION

The use of Acuseal arteriovenous graft (AAVG) is spreading in end-stage renal disease (ESRD) patients for its advantages in early cannulation. However, comparison of clinical outcomes between AAVGs and standard arteriovenous grafts (SAVGs) is limited. In this study, we compared the performance of AAVGs and SAVGs.

METHODS

Consecutive ESRD patients underwent prosthetic vascular access between October 2017 and May 2019 at a single center were identified. Patients were divided into AAVG group and SAVG group. Patients' demographics, perioperative characteristics, and clinical outcomes were collected. Primary, primary assisted, and secondary patency rates were compared using Kaplan-Meier analyses. Postsurgery complications were compared using chi-square test or the Fisher's exact test.

FINDINGS

A total of 304 arteriovenous grafts (AVGs) were implanted in 145 males and 159 females (mean age, 60.1 years; range, 20-91 years), comprising 143 AAVGs and 161 SAVGs. Median time to first cannulation was 3 days (interquartile range [IQR], 1-15 days) in the AAVG group and 30 days (IQR, 20-52 days) in the SAVG group (P < 0.001). Adjusted primary, primary assisted, and secondary patency at 12 months were not significant different between AAVGs and SAVGs (P = 0.911, P = 0.945, and P = 0.640, respectively). There was no statistical significance in regards to thrombosis (AAVG, 34.3%; SAVG, 26.1%; P = 0.120) and infection (AAVG, 4.9%; SAVG, 2.5%; P = 0.261) between the groups.

DISCUSSION

Acuseal grafts provide comparable patency, and complication rates to SAVGs, with less time to first cannulation from the graft implanted.

A Novel Hybrid Silk Fibroin/Polyurethane Arteriovenous Graft for Hemodialysis: Proof-of-Concept Animal Study in an Ovine Model

To solve the problem of vascular access failure, a novel semi-degradable hybrid vascular graft, manufactured by electrospinning using silk fibroin and polyurethane (Silkothane), has been previously developed and characterized in vitro. This proof-of-concept animal study aims at evaluating the performances of Silkothane grafts in a sheep model of arteriovenous shunt, in terms of patency and short-term remodeling. Nine Silkothane grafts are implanted between the common carotid artery and the external jugular vein of nine sheep, examined by palpation three times per week, by echo-color Doppler every two weeks, and euthanized at 30, 60, and 90 days (N = 3 per group). At sacrifice, grafts are harvested and submitted for histopathology and/or scanning electron microcopy (SEM). No cases of graft-related complications are recorded. Eight of nine sheep (89%) show 100% primary unassisted patency at the respective time of sacrifice (flow rate 1.76 ± 0.61 L min^-1 , one case of surgery-related thrombosis excluded). Histopathology and SEM analysis evidence signs of inflammation and pseudointima inside the graft lumen, especially at the venous anastomosis; however, endoluminal stenosis never impairs the functionality of the shunt and coverage by endothelial cells is observed. In this model, Silkothane grafts grant safety and 100% patency up to 90 days.

Challenges and novel therapies for vascular access in haemodialysis

Advances in standards of care have extended the life expectancy of patients with kidney failure. However, options for chronic vascular access for haemodialysis - an essential part of kidney replacement therapy - have remained unchanged for decades. The high morbidity and mortality associated with current vascular access complications highlights an unmet clinical need for novel techniques in vascular access and is driving innovation in vascular access care. The development of devices, biological approaches and novel access techniques has led to new approaches to controlling fistula geometry and manipulating the underlying cellular and molecular pathways of the vascular endothelium, and influencing fistula maturation and formation through the use of external mechanical methods. Innovations in arteriovenous graft materials range from small modifications to the graft lumen to the creation of completely novel bioengineered grafts. Steps have even been taken to create new devices for the treatment of patients with central vein stenosis. However, these emerging therapies face difficult hurdles, and truly creative approaches to vascular access need resources that include well-designed clinical trials, frequent interaction with regulators, interventionalist education and sufficient funding. In addition, the heterogeneity of patients with kidney failure suggests it is unlikely that a 'one-size-fits-all' approach for effective vascular access will be feasible in the current environment.

Use of a novel immediate access dialysis graft designed to prevent needle-related complications: A first-in-man case report

Currently, there is no vascular access that possesses all ideal qualities for hemodialysis access, but attributes particularly lacking include: ease of identification (cannulation zone), ease of access, resistance to stenosis, durable to repetitive cannulation, resistance to infection, resistance to acute needle-related injuries, and instant hemostasis. The overall value of these attributes could be appreciated in the reduction of complications (patient burden and suffering, which can also result in increased healthcare costs), and improved safety and durability. In this case report, we present a novel hemodialysis access graft that has the potential to provide the following benefits: it is designed to be self-sealing and immediately usable post implant, easy to identify, easy to access, has more durable cannulation zones, and protects from needle-related injuries. This case report describes the first-in-man use of this novel graft technology to replace a giant, thrombotic, and difficult-to-access arteriovenous fistula to provide the patient with a potentially safer and more durable access that does not require placement of a bridging dialysis catheter. This single-patient experience suggests that implantation and function of this novel graft as a hemodialysis access is feasible in a human subject with end-stage renal disease, and it suggests that the novel properties (i.e. immediate use, easy identification, easy use, cannulation zone durability, and protection from needle-related injuries) of this graft seem to function as intended.