Use of Expanded Polytetrafluoroethylene–covered Nitinol Stents for the Salvage of Dysfunctional Autogenous Hemodialysis Fistulas

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.

Stent graft deployment in haemodialysis fistula: patency rates in partially thrombosed aneurysm and residual thrombi

Background

Current evidence is insufficient to determine the contribution of stent grafts as treatment in partially thrombosed aneurysms or residual wall-adherent thrombi in arteriovenous fistulae (AVFs) for haemodialysis. The overall purpose of this study was to analyse patency rates of post-interventional covered stent deployment in those cases. We also assessed if patency rates differed when fistulas were punctured through the stent during dialysis sessions.

Methods

We conducted a retrospective study between 2006 and 2014 analysing post-intervention primary patency rates using the Kaplan-Meier log-rank test. Multivariate Cox proportional regression models were performed to determine if cannulation within the stent graft area was a potential risk factor for occlusion, by adjusted hazard ratio (HR).

Results

A total of 27 procedures were included in the study. Primary patency rates (%) after stent deployment at 3, 6, 12, 24, 36 and 72 months were, respectively: total 59, 32, 32, 21, 11 and 5; stent puncture 53, 21, 21, 16, 5 and 0; and no stent puncture 80, 80, 80, 40, 40 and 40. Cannulation through the stent graft was not significantly associated with increased risk of obstruction in multivariate analysis (HR = 3.01; P = 0.286).

Conclusion

Stent graft treatment may be a feasible procedure in partially thrombosed aneurysms and residual thrombi in AVF. Although fistulas punctured through the stent presented lower patency rates, this practice was not associated with a higher risk of obstruction. Giving the impossibility of comparing with similar approaches, further studies are needed to confirm or refute the advantages of this procedure.

A Hybrid Approach to Salvage a Failing Long-Standing Autogenous Aneurysmal Fistula in a Hemodialysis Patient

Very few studies have addressed the repair of autogenous and prosthetic-related false arteriovenous access (AVA) aneurysms in hemodialysis patients. Surgical management of complicated AVA-related aneurysms remains the gold standard method although covered stents have recently been introduced for the exclusion of such aneurysms, offering a minimally invasive therapy. In this paper, we describe a combination of open and endovascular repair for treating an anastomotic and a puncture-site aneurysm to salvage a failing long-standing autogenous radial-cephalic fistula in the wrist. Resection of the anastomotic aneurysm and reconstruction of the anastomosis proximally was initially performed. Via the first cm of the anastomosis, a Fluency® stent graft (SG) was inserted and it successfully excluded the mid-outflow vein false aneurysm. Such hybrid therapies may be the future of AVA revisions and this trend should not be overlooked by nephrologists and vascular surgeons.

Stent tunnel technique to save thrombosed native hemodialysis fistula with extensive venous aneurysm

INTRODUCTION AND PURPOSE

The increasing number of patients undergoing hemodialysis and the limited number of access sites have resulted in an increasing number of techniques to maintain vascular access for hemodialysis. Thrombosed arteriovenous (AV) fistulas with large venous aneurysms have poor treatment results, with both endovascular and surgical techniques, leading to a high rate of definitive AV access loss. The purpose of this study was to review the feasibility and initial results of this novel endovascular treatment of thrombosed AV fistulas with large venous aneurysms.

MATERIALS AND METHODS

A novel endovascular treatment technique of inserting nitinol auto-expandable uncovered stents stretching through the whole puncture site area, thus creating a tunnel inside the thrombus, was retrospectively analyzed and described.

RESULTS

A total of 17 stents were placed in 10 hemodialysis fistulas, with a mean venous coverage length of 17.8 cm. In all the cases, 100% technical success was achieved, with complete restoration of blood flow in all patients. There were no procedure-related complications. The mean follow-up was 167 days (range 60-420 days), with a primary and assisted patency of 80% and 100%, respectively. No multiple trans-stent struts-related complications were observed. Three stent fractures were diagnosed with plain films at the site of puncture without consequence in the venous access permeability.

CONCLUSION

The "stent tunnel technique" is a feasible, safe and effective alternative to salvage native hemodialysis access, thus extending the function of the venous access with no signs of stent-related complications and a respectable midterm patency.

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

Stent grafts (SGs) are widely used for treatment of failing vascular accesses, fistulas and grafts. The mechanical barrier of the covered stent prevents in-stent stenosis and can be used to effectively correct ruptured vein and aneurysms. Treatment of cannulation zone stenosis with SG can be justified when its use is obligatory, in order to prevent total access loss. Although there are worrying complications attendant on SG insertion and cannulation, including jeopardizing future access creation, most studies report no complications of SG in cannulation zone stenosis. SGs for treatment of arteriovenous graft venous anastomosis stenosis is controversial. Two large randomized trials conclusively demonstrate improved primary patency with SGs at the venous anastomosis of arteriovenous graft at up to two years when compared with percutaneous transluminal angioplasty, sustained for up to 2 years and reducing the number of interventions per patient year. However, the ultimate goal of SG treatment of venous anastomosis stenosis is preventing thrombosis and increasing graft longevity, which was unfortunately not fully achieved.

Use of Hybrid Vascular Grafts in Failing Access for Hemodialysis: Report of Two Cases

Purpose

Vascular access morbidity represents one of the most common indications for readmission in patients with end-stage renal disease (ESRD). We report the use of hybrid grafts in two patients for revision of failed vascular access for hemodialysis (HD).

Case Presentations

The first patient was a 45-year-old woman with ESRD who presented with an arteriovenous graft (AVG) that had required multiple interventions for maintenance in whom much of the graft was lined with covered stents. The patient presented with erosion of a stent in the AVG through the skin to the emergency department. The second patient was a 41-year-old man with ESRD who also had an AVG that had required multiple interventions for maintenance. He presented to clinic with chronic bleeding from the AVG after HD sessions. Both patients were taken to the operating room for salvage of part of the AVG through the use of hybrid vascular access grafts. The patients have passed six and three months from the procedure, respectively, without needing additional interventions.

Conclusions

This technique demonstrates successful use of hybrid vascular access grafts, specifically inside existing grafts in locations that contain stents utilizing the existing venous resources in that arm to carry out the surgical repair, thereby preserving venous capital.

Role of stent grafts for the treatment of failing hemodialysis accesses

Covered stents or stent grafts are exciting new products with multiple applications for patients with vascular disease, including hemodialysis access-related complications. Although most of the current uses of stent grafts in these settings are "off-label" (ie, not approved by the US Food and Drug Administration) several studies are currently underway to provide the necessary data to support their application. It is clear that stent grafts provide a rapid, effective means for endovascular repair of ruptured access vessels. The commercially available devices and their current applications for treating access-related complications, including aneurysms/pseudoaneurysms, venous outflow stenoses, cephalic arch lesions, ruptures, and diffuse access stenoses, will be reviewed in this article. Available data are reported along with our current clinical practice and algorithms.

Endovascular stents for dialysis access: under what circumstances do the data support their use?

Despite strict K/DOQI clinical practice guidelines regarding the deployment of stents in the hemodialysis vascular circuit, their use has increased exponentially over the last 10 years in both arteriovenous fistulas and grafts. The literature is very scant regarding outcomes, with most studies suffering from design flaws. Some authors have advocated the use of stents for specific clinical scenarios, such as patients with thrombosed arteriovenous grafts or ones with a severe stenosis at the venous anastomosis. Others have advocated a more liberal strategy to deploy stents at a variety of sites if the stenotic lesion remains greater than 30% after angioplasty. Although not approved for the treatment of pseudoaneurysms in the AV grafts, stent use in this setting is emerging to be an important strategy. The use of stents as a treatment for rupture of a vessel while performing a percutaneous angioplasty is well described and performed routinely. It is important to recognize the clinical scenarios when stent placement may present a distinct disadvantage (eg, loss of a potential secondary fistula creation in the same extremity). Finally, well-designed studies need to address all these issues to clarify indications and to provide stronger scientific guidelines for stent use.