Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

Covered stents versus balloon angioplasty for failure of arteriovenous access: a systematic review and meta-analysis

INTRODUCTION

Patients with end-stage renal disease may require arteriovenous (AV) access in the form of arteriovenous fistulae (AVFs) or arteriovenous grafts (AVGs) for haemodialysis. AV access dysfunction requires intervention such as plain balloon angioplasty or covered stents to regain patency.

AIM

To systematically review and meta-analyse the patency outcomes of covered stents in failing haemodialysis AV access, compared with balloon angioplasty.

METHODS

The review was first registered on the International Prospective Register of Systematic Reviews (CRD42018069955) before data collection. We searched six electronic databases to identify relevant randomised controlled trials (RCTs) up until August 2020, without language restriction. Two reviewers assessed the suitability and quality of studies for inclusion using the Consolidated Standards of Reporting Trials guidelines. We meta-analysed data using a random-effects model.

RESULTS

We included seven studies including 1147 patients in the systematic review, of which 867 had AVGs and 280 had AVFs. One study was an ongoing RCT. In the meta-analyses, we assessed patients with failing AVGs only. Overall risk of bias was moderate. Covered stents were associated with lower loss of patency versus angioplasty alone at 6, 12 and 24 months (OR 4.48, 95% CI 1.98 to 10.14, p<0.001; OR 4.07, 95% CI 1.74 to 9.54, p=0.001; OR 2.24, 95% CI 1.17 to 4.29, p=0.01, respectively). Covered stents afforded superior access circuit primary patency compared with angioplasty alone at 6 and 12 months (OR 1.91, 95% CI 1.31 to 2.80, p<0.001; OR 1.97, 95% CI 1.14 to 3.41, p=0.02, respectively). This was not significant at 24 months. There was no significant difference in loss of secondary patency between groups at 12 or 24 months (OR 0.74, 95% CI 0.45 to 1.23, p=0.25; OR 0.67, 95% CI 0.29 to 0.154, p=0.34, respectively).

CONCLUSION

Our results support use of covered stents over angioplasty alone, at 6, 12 and 24 months in failing AVGs. Further clinical trials are warranted.

Randomized Controlled Trial for Paclitaxel-coated Balloon versus Plain Balloon Angioplasty in Dysfunctional Hemodialysis Vascular Access: 12-month Outcome from a Nonsponsored Trial

BACKGROUND

Plain balloon angioplasty is regarded as the mainstay of treatment for failing vascular access with high success rate, but the poor treatment durability creates significant workload and increases patient morbidity. The study aims to compare target lesion primary patency rate at 12 months between paclitaxel-coated balloon (DCB) versus plain old balloon angioplasty (POBA) for treatment of dysfunctional vascular access.

METHODS

This nonsponsored-randomized trial enrolled 40 patients with dysfunctional dialysis access at a single center. Patients were randomized into In.Pact Admiral Paclitaxel DCB or POBA after lesion crossing regardless of lesion type. Patients are followed up under surveillance protocol. Patients, hemodialysis staff, and sonographer are blinded to the treatment arms. Twelve-month primary patency rate in both arms are evaluated.

RESULTS

40 patients were recruited since June 2016 and were allocated to the DCB or POBA group. The mean age is 58 and 57 years with comparable demographic parameters. The locations of target lesion were comparable in both groups (juxta and arteriovenous anastomosis, cannulation site, and fistula/graft), with similar mean target lesion stenosis 69.8 +/- 15.8% for DCB and 69.5 +/- 13.6% for POBA (P = 0.95), and the lesion length for DCB is 45.8 +/- 38.4 mm and 50.2 +/- 33.5 mm for POBA (P = 0.70). Patients in DCB performed significantly better in terms of primary patency at 6 months 85% versus 55% (P = 0.007). The superiority in primary patency in DCB group exists at 12 months 65% versus 30% (P = 0.007).

CONCLUSIONS

Paclitaxel balloon angioplasty approach provides significant better primary patency in dysfunctional arteriovenous access at 12 months in our nonsponsored-randomized trial.

Efficacy of Primary Stent-Graft Placement in the Treatment of Vascular Access Graft Outflow Tract Stenosis

PURPOSE

The aim of this study is to present our personal experience using covered nitinol stent-graft in the treatment of outflow tract stenosis of arteriovenous grafts (AVGs) for hemodialysis access.

MATERIALS AND METHODS

Between May 2015 and October 2017, we retrospectively evaluated 36 (24 males, 12 females; mean age: 65.6 years) patients with AVGs on hemodialysis who underwent percutaneous angioplasty followed by endovascular stent-graft deployment for the treatment of stenosis of the venous outflow of the AVG. Indication for treatment included early restenosis (<3 months after previous percutaneous transluminal angioplasty [PTA]), long stenosis (stenoses >50% extending for a length >5 cm), and recoil of the stenosis after PTA performed with a noncompliant high-pressure balloon. Of 36 patients, 27 (75%) required surgical thrombectomy prior to endovascular procedure. Technical success, clinical success, primary and secondary patency, and safety were evaluated.

RESULTS

Technical success was 100%, and clinical success was 94.4%. Primary patency was 94.4%, 72.2%, 63%, 45.9%, and 45.9% at 1, 3, 6, 12, and 18 months (average: 215 days, range: 9-653 days); secondary patency was 94.4% and 86.1% at 1 and 3 months; 80.4% at 6, 12, and 18 months; and 53.6% at 24 months (average: 276.8 days, range: 9-744 days). No deaths were registered.

CONCLUSIONS

In selected cases, the use of stent-graft represents an effective and safe solution for the treatment of stenotic complications of the venous outflow of AVGs, even in the setting of access thrombosis.

Long-term results of endovascular treatment for arteriovenous dialysis access thrombosis in 143 patients: A single center experience

Objective:

This study aimed to determine the long-term patency duration and rate of thrombosis of autologous arteriovenous fistulas and synthetic grafts treated with endovascular methods in a large patient population.

Methods:

A total of 144 arteriovenous accesses (37 radiocephalic, 51 brachiobasilic, 41 brachiocephalic, and 15 femorofemoral) from 143 patients were included in the study. A total of 304 endovascular thrombolytic treatment procedures were performed for 94 (65%) arteriovenous fistula and 50 (35%) arteriovenous graft accesses.

Results:

The procedural technical success rate was 98.7%. The mean follow-up duration was 32.5 (range, 3–132) months. The primary patency rates for arteriovenous fistulas and arteriovenous grafts were 78% and 78% at 6 months, 66% and 63% at 1 year, and 45% and 0% at 36 months, respectively. The assisted primary patency rates for arteriovenous fistulas and arteriovenous grafts were 82% and 84% at 6 months, 71% and 69% at 1 year, 51% and 29% at 36 months, and 30% and 1% at 60 months, respectively. The secondary patency rates for arteriovenous fistulas and arteriovenous grafts were 94% and 93% at 6 months, 85% and 85% at 1 year, 58% and 59% at 36 months, and 47% and 48% at 60 months, respectively.

Conclusion:

Although the primary patency durations for arteriovenous fistulas were better after endovascular thrombolytic treatment than those for arteriovenous grafts, the long-term outcomes of assisted primary and secondary patency durations after repeated procedures were similar for both types of arteriovenous accesses.

Viabahn stent for hemodialysis shunt: efficacy, long segment recanalization and prognostic factors for reintervention

INTRODUCTION

The study evaluated the Heparin Bioactive Surface (HBS) Viabahn Stent (W.L. Gore & Associates, Flagstaff, Arizona) efficacy in the maintenance or re-establishment of hemodialysis.

MATERIALS AND METHODS

Fifty HBS Viabahn stents deployed in 37 consecutive patients with hemodialysis dysfunction from January 2008 to May 2016 were evaluated in a single-institution retrospective review. Outcomes were stent patency intended as primary circuit patency (PP), assisted primary patency (APP), target lesion primary patency (TLPP) and secondary patency (SP). Moreover, the risk factor analysis for hemodialysis dysfunction that required reintervention was performed. A subgroup analysis was conducted to assess patency of Viabahn stent to treat peripheral venous long segment obstruction (LSO).

RESULTS

Overall Kaplan-Meyer PPs were 60% at 12 months and 42% at 24 months. Overall TLPP estimated rates were 68% and 49% at 12 and 24 months, respectively. The corresponding SP rates were 85% and 78% at the same period. Estimated PP rates at 12 and 24 months for stent placement after peripheral venous long segment recanalization procedure were 53% and 31%, respectively. Corresponding SP rates were 82% and 68%, respectively. The APP rates were 79% at 12 months and 61% at 24 months. Female sex, access age and thrombosis were associated with reduced primary patency.

CONCLUSIONS

Considering the high rates of PP, TLPP, APP and SP, Viabahn stents have been proven effective in maintaining or re-establishing the hemodialysis access. Moreover, stent placement after recanalization of LSO of venous out-flow represented a valid approach to rescue a dysfunctional fistula that would otherwise be abandoned.

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.

Treatment of central venous in-stent restenosis with repeat stent deployment in hemodialysis patients

Purpose

To report patency rates for stent deployment for treatment of in-stent stenosis of the central veins of the chest in hemodialysis patients.

Materials and Methods

A retrospective analysis was performed on 29 patients who underwent 35 secondary percutaneous transluminal stent (PTS) deployments for in-stent stenosis within the central veins that were refractory to angioplasty and ipsilateral to a functioning hemodialysis access (in-stent PTS group). For comparison, patency data were acquired for 47 patients who underwent 78 successful percutaneous transluminal angioplasty (PTA) procedures for in-stent stenosis (in-stent PTA group) and 55 patients who underwent 55 stent deployments within native central vein stenosis refractory to angioplasty (native vein PTS group).

Results

The 3-, 6-, and 12-month primary lesion patency for the in-stent PTS group was 73%, 57%, and 32%, respectively. The 3-, 6-, and 12-month primary patency for the in-stent PTA group was 70%, 38%, and 17% and for the native vein PTS group was 78%, 57%, and 26%, which were similar to the in-stent PTS group (p = 0.20 and 0.41, respectively). The 3-, 6-, and 12-month secondary access patency was 91%, 73%, and 65% for the in-stent PTS group. Sub-analysis of the in-stent PTS group revealed no difference in primary (p = 0.93) or secondary patency rates (p = 0.27) of bare metal stents (n = 23) compared with stent grafts (n = 12).

Conclusions

Stent deployment for central vein in-stent stenosis refractory to angioplasty was associated with reasonable patency rates, which were similar to in-stent PTA and native vein PTS.

Stent Grafts Provided Superior Primary Patency for Central Venous Stenosis Treatment in Comparison with Angioplasty and Bare Metal Stent: A Retrospective Single Center Study on 70 Hemodialysis Patients

PURPOSE

To compare patency in dialysis patients following different endovascular treatment of symptomatic central venous stenosis.

MATERIALS AND METHODS

A 10-year retrospective evaluation in 70 patients (32 men) dialyzing through vascular access (33, 47%) and tunneled catheters (37, 53%) was made. Three cohorts were compared: angioplasty alone (22), bare metal stent (28), and stent graft (20). Patencies were described with Kaplan-Meier method, and Cox uni- and multivariate models were analyzed to find factors associated.

RESULTS

All patients had a favorable anatomical and clinical outcome. Restenosis occurred in 22 (31%) of 70 patients requiring 41 additional interventions; 34 of 70 patients died (median follow-up 19.4 months). Primary patency at 3, 6, 12, and 24 months was 100%, 100%, 100%, and 84% for stent graft versus 90%, 79%, 58%, and 43% for angioplasty (P = .014) versus 84%, 80%, 75%, and 46% for bare-metal stent (P = .062). The overall comparison was more favorable for stent graft (P = .020) when the sites of lesions were matched. Patencies for angioplasty and bare-metal stents were equivalent (P = .141). A lower risk of restenosis (hazard rate [HR] 0.20, confidence interval [CI] 0.06-0.7) and fewer reinterventions (P < .01) were associated with stent graft, whereas age (HR 1.04, CI 1.001-1.08) and cardiovascular disease (HR 2.26, CI 1.06-4.84) influenced the overall survival. No difference in assisted primary patency was found.

CONCLUSION

Stent graft seems to improve primary patency for central venous stenosis and requires fewer reinterventions in a dialysis population with a high prevalence of long-term catheters.