Stent grafts for treatment of cannulation zone stenosis and arteriovenous graft venous anastomosis

SUPERA stent placement for salvaging early recurrent arteriovenous graft thrombosis after percutaneous transluminal angioplasty: A single-center study

BACKGROUND

The aim of this study was to evaluate the patency of the helical interwoven SUPERA stent for salvaging prosthetic arteriovenous (AV) grafts with rapidly recurrent thrombotic occlusion developed within a short time period after successful percutaneous transluminal angioplasty.

METHODS

From December 2019 to September 2021, the data of 20 patients with AV graft who had the SUPERA stent inserted satisfying the following conditions were consecutively collected. (1) More than 1 year has passed since the AV access operation; (2) Thrombotic re-occlusion of AV graft occurred within 3 months after previous successful endovascular treatment; (3) Residual stenosis is greater than 30% after full effacement of balloon angioplasty in the primary lesion. Post-interventional target lesion primary patency (TLPP), access circuit primary patency (ACPP), and secondary patency (SP) were calculated.

RESULTS

Primary lesions of early recurrent arteriovenous graft thrombosis were found in 13 patients with graft-vein anastomosis, six patients with intra-graft stenosis, and one patient with outflow vein complications. The lesions showed residual stenosis in 47.4% (interquartile range: 44.1%-55.3%) of patients despite full-effacement balloon angioplasty. Clinical success was achieved in all patients with full-expansion of the stents at the 1-month follow-up. The TLPP was 70.7% and 32% at 6 and 12 months, respectively, and ACPP was 47.5% and 6.8% at 6 and 12 months, respectively. The SP was 76.1% and 57.1% at 6 and 12 months, respectively. No cannulation complications occurred in the six patients with installation inside the graft. No hemodialysis or stent fracture occurred in any patient during the follow-up period.

CONCLUSIONS

The SUPERA stent may have a role in salvaging AV grafts with early recurrent thrombosis due to its greater radial force and its conformability and can be useful in treating stenosis involving the elbow or axilla, with fair patency and low complication rates.

Patency and Durability of Stent Grafts Placed in the Dialysis Circuit Cannulation Zone

PURPOSE

To investigate the safety, durability, and patency rates of stent grafts (SGs) placed in the cannulation zone of hemodialysis access circuits.

MATERIALS AND METHODS

From April 2020 to April 2023, all procedures with SGs placed in the cannulation zone were retrospectively analyzed. A total of 40 patients (25 men and 15 women) with SGs placed in the cannulation zone were included in the study. Mean age of the patients was 70 years. The Covera covered stent (BD, Franklin Lakes, New Jersey) was used in all cases. Of these, 26 were arteriovenous (AV) fistulae and 14 were AV grafts. SGs were placed for residual stenosis, perforation, aneurysm, and thrombosis. Follow-up outcomes were determined using follow-up angiographic images and included primary patency, primary-assisted patency, and secondary patency.

RESULTS

The primary patency of the target lesion was 89% (SD ± 5) and 74% (SD ± 8.4) at 6 and 12 months, respectively. The primary-assisted patency was 89% (SD ± 5.2) and 78% (SD ± 7.6) at 6 and 12 months, respectively. Secondary patency of the access circuit was 97% (SD ± 2.5) at both 6 and 12 months. Mean follow-up was 332 days (range, 28-661 days). All SGs were successfully cannulated for hemodialysis. No cases of stent fracture or stent infection were observed during follow-up.

CONCLUSIONS

SGs placed for cannulation zone pathologies can be safely cannulated for dialysis and have adequate short- and mid-term patency rates.

The role of stents in hemodialysis vascular access

Vascular access is the Achilles' heel of dialysis therapy among patient with end stage kidney disease. The development of neointimal hyperplasia and subsequent stenosis is common in vascular access and is associated with significant morbidity. Percutaneous transluminal angioplasty using balloon inflation was the standard therapy of these lesions. However, the balloon-based approaches were associated with poor vascular access patency rate necessitating new inventions. It is within this context that different types of stents were developed in order to improve the overall dialysis vascular access functionality. In this article, we review the available literature regarding the use of stents in treating dialysis vascular access stenotic lesions. Further, we review the major clinical trials of stent use in different anatomic locations and in different clinical scenarios.

ASDIN white paper: Management of cephalic arch stenosis endorsed by the American Society of Diagnostic and Interventional Nephrology

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

A UK Expert Consensus Approach for Managing Symptomatic Arteriovenous Fistula (AVF) Stenosis in Haemodialysis Patients

PURPOSE

Stenoses in mature arteriovenous fistulas (AVFs) are common and can negatively impact on the quality of haemodialysis, the longevity of the AVF and lead to debilitating symptoms. Multiple treatment options exist; however, management can vary between different centres. We aimed to establish multidisciplinary consensus on the optimal stepwise application of interventions based on evidence and consensus.

METHODS

A modified Delphi process was conducted with 13 participants from hospitals across the UK, all of whom have high-volume dialysis access practice.

RESULTS

The usual intervention to rectify de novo stenoses of mature AVFs is fistuloplasty, although surgery for inflow segment stenoses is also clinically acceptable. Appropriate first-line interventions include plain old balloon angioplasty or high-pressure balloon angioplasty; if these fail during the fistuloplasty, consider upsizing the balloon, prolonged balloon inflation or using alternative interventions, such as cutting or scoring balloons and ultra-high-pressure balloons. Alternative or subsequent interventions vary by anatomical site and may require additional multidisciplinary team input. For a stenoses recurring between 3 and 12 months, it is appropriate to consider interventions used de novo, but with a lower threshold for using drug-coated balloons (DCBs) in all regions and for using stent grafts in all regions but inflow segment. Recurrence after 12 months should be treated as a de novo lesion, with DCBs considered if they have been used successfully during previous interventions.

CONCLUSIONS

These recommendations aim to provide a practical guide to multidisciplinary teams in order to optimise the use of multiple interventions for rectifying AVF stenoses and provide unified evidence-based practice guidelines.

Salvage of autogenous dialysis access with balloon-assisted thrombin injection

Arteriovenous fistulas are known to be one of the most enduring and safe hemodialysis access modalities. However, access preservation can be challenging in the setting of degeneration, including the development of complex pseudoaneurysms. Prolonged compression or thrombin injection can risk thrombosis of the fistula, and covered stent use can predispose the access to infection and other stent complications. We present a case in which endovascular balloon occlusion was used to facilitate the use of ultrasound-guided thrombin injection to resolve a dialysis access pseudoaneurysm by transiently reducing flow and preventing thromboembolism. This method is a safe, effective, and minimally invasive technique that should be considered for salvage of autogenous access compromised by pseudoaneurysm development.

Efficacy and safety of secondary procedures for maintaining arteriovenous hemodialysis access patency: protocol for a systematic review and network meta-analysis

BACKGROUND

Arteriovenous (AV) hemodialysis access creation is recommended by international guidelines as the preferred method of hemodialysis access. However, most AV access sites will require revision to maintain patency. Although several treatment options exist, many have not been directly compared. We intend to compare the relative effectiveness of methods to maintain post-intervention primary patency of failing AV access.

METHODS

We will search EMBASE, MEDLINE, CENTRAL, trial registries, the grey literature, and ancestry and citation search from January 1977 to present, for randomized controlled trials comparing interventions to maintain primary patency of AV access. Two investigators will independently and blindly review all identified citations and extract data from included studies. The primary outcome is the primary patency 6 months after intervention. Secondary outcomes include immediate technical and functional success, reinterventions, patency, and mortality. Risk of bias, subgroup analyses, and sensitivity analyses are planned.

DISCUSSION

There are a number of treatment modalities for the management of failing AV access. However, most modalities have only been directly compared with plain old balloon angioplasty, and currently synthesized evidence focuses on individual pairwise comparisons. In light of the lack of comprehensively synthesized evidence and clinical equipoise, our study intends to synthesize currently available evidence though it is unclear which treatment modality is most effective.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID CRD42020148224.

Use of the Covera Stent Graft for the Treatment of Dysfunctional or Thrombosed Arteriovenous Grafts: A Retrospective Analysis of 64 Patients

PURPOSE

To retrospectively evaluate the safety and effectiveness of the Covera stent graft (SG) for the treatment of dysfunctional or thrombosed arteriovenous grafts (AVGs).

MATERIALS AND METHODS

Within 29 months (February 2016-August 2018), 79 patients underwent Covera SG placement in the authors' department for the treatment of dysfunctional AVGs. Data were available for 64 patients who underwent 64 procedures, using 64 devices. Minimum follow-up was 6 months, unless reintervention occurred. Mean follow-up was 277 days (6-923 days). Treatment characteristics were 51 cases with venous-graft anastomosis (VGA) stenosis (79.7%), 13 cases of puncture zone stenosis (20.3%), 14 cases of in SG stenosis (21.9%), 8 cases of pseudoaneurysm treatment (12.5%) (1 treatment area might have had more than 1 characteristic). Thirty-six patients presented with thrombosis (56.2%), and 31 of 64 case were de novo treatment areas (48.4%). Primary outcome measurements were technical success and post-intervention primary patency (PIPP) at 6 months, whereas secondary outcome measurements included factors influencing primary outcome.

RESULTS

Technical success was 100%. Median PIPP was 336 days, and 73.6% of treatment areas were patent at 6 months. There were no significant differences in terms of PIPP when de novo treatment areas were compared with restenotic areas (519 vs. 320 days, respectively; P = .1); patients who presented with versus those who presented without thrombosis (320 vs. 583 days, respectively; P = .07); puncture zone stenosis or elsewhere (329 vs. 686 days, respectively; P = .52); and VGA stenosis or elsewhere (336 vs. 335 days, respectively; P = .9).

CONCLUSIONS

Use of the Covera SG for AVG treatment was safe and effective in every type of treatment area presented in this retrospective analysis.