Comparison of end-to-side versus side-to-side anastomosis in upper limb arteriovenous fistula in hemodialysis patients: A systematic review and meta-analysis

A review of technical steps in the performance of arteriovenous fistula creation

Although it is accepted that a functional arteriovenous fistula (AVF) is the optimal vascular access for dialysis, achieving function is difficult as the outcomes of AVF creation are sub-optimal. Many technical steps have been proposed to improve outcomes, but the strength of evidence to support these is unclear. Thus, a systematic review of all randomised controlled trials (RCT) of operative strategies to optimise AVF outcomes was performed to summarise the evidence, review the overall level of standardisation in RCT and thus determine if there was an objective basis for the technical steps in AVF creation. A systematic review of all RCT was performed and studies categorised by intervention type. The rationale for each intervention, outcomes and limitations were described. Most importantly, the completeness of reporting procedural steps was compared for all RCT and the therapeutic impact considered by AVF site. Of 6741 records meeting the search criteria, 31 RCT were included. Most RCT did not control for all technical aspects or fully detail the operative methods, with a mean of 4 technical steps not reported for which other RCT have been performed. Of studies involving a surgical intervention in RCF, 10/13 reported a significant benefit compared to only 5/15 studies in BCF or larger vessels. Overall, the adequacy of reporting the technical details in all RCT of technical steps in AVF creation was poor. Despite this, there was a consistent patency benefit found in RCT performed in smaller vessels although the extent of interaction between these is uncertain. There remain gaps in the literature in defining the optimal steps in fistula creation that, if confirmed, could significantly improve AVF outcomes. This makes it essential that future studies of novel techniques, such as percutaneous AVF creation, incorporate a standardised operating procedure of optimal current practice of surgically created AVF as a meaningful comparator.

A practical review of barriers and challenges to a definitive randomised trial of grafts versus fistula

A definitive randomised controlled trial of arteriovenous fistula (AVF) versus arteriovenous grafts (AVG) has been advocated for more than a decade, but as yet, none has been completed. The aim of this article is to summarise the theoretical barriers, review the difficulties in trial design and practicalities that have thus far prevented this from occurring.

Hemodynamic considerations in arteriovenous vascular access modalities for hemodialysis

Arteriovenous fistulas and arteriovenous grafts are the most commonly used vascular access for hemodialysis in patients with end-stage chronic kidney disease. However, both methods face significant challenges due to the hemodynamic disturbances induced by the arteriovenous anastomosis. This causes changes in vascular structure and blood flow velocity near the anastomosis site after the fistula/graft surgery, and introduces abnormal wall shear stress and cyclic stretch. This leads to endothelial cell dysfunction, vascular smooth muscle cell proliferation, and adverse remodeling. The resulting effects include low patency rates due to vascular stenosis caused by intimal hyperplasia and insufficient outward remodeling. Additionally, the high flow conduit has been linked to adverse cardiac remodeling. To address this, various strategies have been explored to correct these localized hemodynamic abnormalities, aiming to improve long-term patency rates. In this review, an overview is provided of the current surgical techniques, anastomosis types, anastomosis angles, external scaffolds, modified fistula designs, and types of grafts. It evaluates the impact of these approaches on local hemodynamics in the access conduit and their potential effects on patient outcomes.

Rebuilding vascular access: from the viewpoint of mechanics and materials

This review presents a comprehensive analysis of vascular access in hemodialysis, focusing on the current modalities, their associated challenges, and recent technological advancements. It closely examines the status of three primary types of vascular access: arteriovenous fistulas, arteriovenous grafts, and central venous catheters. The review delves into the complications and pathologies associated with these access types, emphasizing the mechanobiology-related pathogenesis of arteriovenous access. Furthermore, it explores recent clinical trials, biomaterials, and device innovations, highlighting novel pharmaceutical approaches, advanced materials, device designs, and cutting-edge technologies aimed at enhancing the efficacy, safety, and longevity of vascular access in hemodialysis. This synthesis of current knowledge and emerging trends underscores the dynamic evolution of vascular access strategies and their critical role in improving patient care in hemodialysis.

Risk factors for thrombosis in dialysis patients: A comprehensive systematic review and meta-analysis

AIM

To identify the factors associated with thrombosis in dialysis patients.

BACKGROUND

Thrombosis is a leading cause of vascular access failure in dialysis patients. Numerous risk factors contribute to thrombosis in this population.

METHODS

A systematic search was conducted across international databases using standardized keywords. The quality of the selected studies was assessed using the STROBE and CONSORT checklists. The findings were summarized in a Garrard table. Meta-analysis was performed using CMA software. The study adhered to the guidelines outlined in the PRISMA statement.

RESULTS

A total of 180 articles were reviewed. The odds ratio for thrombosis in patients with arteriovenous grafts compared to arteriovenous fistulas was 10.93 (95 % CI: 9.35-12.78), demonstrating statistical significance (P = 0.001). Similarly, hemodialysis patients had an odds ratio of thrombosis 3.60 times higher than non-hemodialysis patients (95 % CI: 3.54-4.19), with statistical significance (P = 0.001). Patients undergoing single-stage basilic vein transposition had a 1.89 times higher risk of thrombosis compared to those undergoing two-stage transposition (95 % CI: 1.04-3.46), also demonstrating statistical significance (P = 0.038).

CONCLUSIONS

Thrombosis in patients with end-stage renal disease undergoing dialysis was significantly associated with various factors, including graft access, single-stage basilic vein transposition, and hemodialysis. Additional contributing factors to thrombosis included diabetes, elevated homocysteine levels, female gender, age over 50, access location, and low access blood flow velocity. The analysis revealed a higher incidence of thrombosis in end-stage renal disease patients undergoing hemodialysis compared to those not undergoing dialysis, as well as in patients with arteriovenous grafts compared to those with arteriovenous fistulas. These findings underscore the importance of recognizing and managing these risk factors to prevent thrombotic events and enhance patient care within the dialysis setting.