Stent graft versus balloon angioplasty for failing dialysis-access grafts

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.

Chronic mesenteric ischemia: Clinical practice guidelines from the Society for Vascular Surgery

BACKGROUND

Chronic mesenteric ischemia (CMI) results from the inability to achieve adequate postprandial intestinal blood flow, usually from atherosclerotic occlusive disease at the origins of the mesenteric vessels. Patients typically present with postprandial pain, food fear, and weight loss, although they can present with acute mesenteric ischemia and bowel infarction. The diagnosis requires a combination of the appropriate clinical symptoms and significant mesenteric artery occlusive disease, although it is often delayed given the spectrum of gastrointestinal disorders associated with abdominal pain and weight loss. The treatment goals include relieving the presenting symptoms, preventing progression to acute mesenteric ischemia, and improving overall quality of life. These practice guidelines were developed to provide the best possible evidence for the diagnosis and treatment of patients with CMI from atherosclerosis.

METHODS

The Society for Vascular Surgery established a committee composed of vascular surgeons and individuals experienced with evidence-based reviews. The committee focused on six specific areas, including the diagnostic evaluation, indications for treatment, choice of treatment, perioperative evaluation, endovascular/open revascularization, and surveillance/remediation. A formal systematic review was performed by the evidence team to identify the optimal technique for revascularization. Specific practice recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation system based on review of literature, the strength of the data, and consensus.

RESULTS

Patients with symptoms consistent with CMI should undergo an expedited workup, including a computed tomography arteriogram, to exclude other potential causes. The diagnosis is supported by significant arterial occlusive disease in the mesenteric vessels, particularly the superior mesenteric artery. Treatment requires revascularization with the primary target being the superior mesenteric artery. Endovascular revascularization with a balloon-expandable covered intraluminal stent is the recommended initial treatment with open repair reserved for select younger patients and those who are not endovascular candidates. Long-term follow-up and surveillance are recommended after revascularization and for asymptomatic patients with severe mesenteric occlusive disease. Patient with recurrent symptoms after revascularization owing to recurrent stenoses should be treated with an endovascular-first approach, similar to the de novo lesion.

CONCLUSIONS

These practice guidelines were developed based on the best available evidence. They should help to optimize the care of patients with CMI. Multiple areas for future research were identified.

Use of the Viabahn covered stent for the treatment of venous rupture during interventions of dysfunctional or thrombosed hemodialysis vascular access

BACKGROUND

Angioplasty-related vessel rupture is a common complication of interventions. The effect of covered stents to treat venous rupture has been evaluated in smaller series, but should be further evaluated.

OBJECTIVE

To report the immediate outcomes and patency rates of a covered stent to rescue angioplasty-related venous rupture of hemodialysis vascular access.

METHODS

From January 2013 to December 2018, 113 procedures complicated with vessel ruptures were retrospectively analyzed from a prospectively collected database of 8146 hemodialysis access interventions. The strategies to salvage vessel ruptures were based on the discretion of the treating physicians. Follow-up outcomes were obtained via review of the angiographic images, procedural notes, and medical and dialysis records within 12 months after the index procedures.

RESULTS

A total of 52 vessel ruptures (21 fistulas, 31 grafts) salvaged by using Viabahn covered stents were enrolled. Vessel ruptures developed in 28 (53.8%) thrombectomy procedures. Device success was achieved in all procedures (100%) and clinical success was achieved in 50 (96.2%). The primary patency of the stent area was 66.0% at 6 months and 50.0% at 12 months. The primary patency of the entire access circuit was 27.4% at 6 months and 16.0% at 12 months. The most common cause of access circuit primary patency loss was thrombotic occlusion for graft accesses and restenosis at stent area for native accesses. Eleven vascular accesses were abandoned within 12 months after vessel ruptures, and the secondary patency rate of the entire access circuit was 78.0% at 12 months.

CONCLUSIONS

Treatment of angioplasty-induced vessel rupture of hemodialysis vascular accesses by using Viabahn covered stents has good immediate outcomes and patency results at the stent area. Nonetheless, the patency rate of entire access circuit was still below the threshold recommended by guidelines.

Outcome of Percutaneous Intervention in Dysfunctional Loop versus Straight Arteriovenous Grafts in Hemodialysis Patients

Objective:

To compare the patency control of dysfunctioning forearm arteriovenous graft (AVG) using percutaneous transluminal angioplasty (PTA) in patients with loop versus straight grafts.

Materials and Methods:

Between January 2012 and March 2017, hemodialysis patients with forearm AVG were treated with PTA at two hospitals. We reviewed technical and clinical success rates of each procedure. Procedure time and patency of the graft were compared for all patients as well as for subgroups of stenosis only and thrombosis using paired-sample t-test and Kaplan-Meier analysis.

Results:

Sixty-six patients (mean age, 62.11 ± 11.85 years) underwent PTA. Thirty-eight patients (58%) had loop grafts and 28 (42%) had straight grafts. Among 66 patients, 54 (82%) had thrombosis. Technical success rate was 95.5% (only stenosis: 100%; thrombosis: 94%) and the mean procedure time was 48.00 ± 16.75 minutes in all patients. Although there was a tendency towards shorter procedure time in patients with loop grafts (45.24 ± 20.24 minutes) than those with straight grafts (51.85 ± 22.76 minutes), the difference was not statistically significant (p = 0.217), with or without thrombi. There was no statistical significance in primary and assisted primary patency (log rank 0.78, p = 0.38 in primary patency; log rank 0.88, p = 0.35 in assisted primary patency).

Conclusion:

Our study suggests there is no different patency outcome between straight and loop arteriovenous grafts after PTA.

The challenge of stent placement within cannulation zones of Arteriovenous Fistulae

BACKGROUND

Stent placement in the cannulation zone of AVF is becoming alarmingly frequent and sometimes in cases where surgical management would be more appropriate. When complications arise repair can be particularly challenging. We present our experience and management of this problem.

METHODS

We report our experience on three patients (two females and one male, mean age 72) that were referred to our department for problems related to stents placed at the cannulation segments.

RESULTS

All patients required complex surgical interventions. In two of them maintenance of access was possible but required the use of a graft. In one complete resection of the AVF and all stents was necessary, and the patient remained on dialysis through catheter.

CONCLUSION

Stent placement at the cannulation zones may complicate access management in the future and should be avoided if possible.

Paclitaxel coated-balloon (PCB) versus standard plain old balloon (POB) fistuloplasty for failing dialysis access

INTRODUCTION

This study aimed to evaluate the safety and efficacy of paclitaxel-coated balloon compared with conventional plain balloon for the treatment of failing native dialysis access.

MATERIALS AND METHODS

This prospective study included 60 patients presenting to the Kasr Alainy Hospitals and Aseer Central Hospital in the period from September 2015 to December 2017 with failing native vascular access. Dilatation with a plain balloon was done in 30 patients (group I) and with a paclitaxel-coated balloon in 30 patients (group II) with either stenosis or occlusion. The majority were outflow lesions, with 20 (66.7 %) patients in group I and 21 (70%) patients in group II. Mean balloon diameter was 7.1mm (± 1.5mm) compared with 6.5mm (± 1.2mm) and length 66mm (± 19.1mm) compared with 54.6mm (± 15.7mm), respectively. Safety endpoint was reported as 30 day's freedom from procedure-related major complications and mortality. Procedural technical success was defined as a residual diameter 30% or less for treated lesions. Target lesion primary patency, circuit primary patency and secondary patency were reported at 3, 6 and 12 months.

RESULTS

There were no 30-day procedure-related major complications or mortality in either group. Procedural technical success of 100% was achieved in both groups. Target lesion primary patency, circuit primary patency and secondary patency in group II were better than in group I, especially at 12 months (90% vs 66.7%, 83.3% vs 60% and 96.7% vs 93.3%, respectively). There was a statistically significant difference in target lesion primary patency (p = 0.029) in patients who were treated with paclitaxel-coated balloon angioplasties.

CONCLUSION

The paclitaxel-coated balloon proved to be safe and effective, and improved the patency of failing vascular access. Results are comparable with previous studies.

Promising results of stent graft placement for cephalic arch stenosis after repeated failure of angioplasty in patients on hemodialysis

Objective

Cephalic arch stenosis (CAS) causes repeated dysfunction and failure of arteriovenous access. Percutaneous transluminal angioplasty is the standard initial treatment for CAS, but its outcome is unsatisfactory. This study aimed to evaluate the outcome of stent graft placement for CAS in patients on hemodialysis.

Methods

A retrospective chart review from a tertiary medical center was performed in patients receiving stent graft placement for CAS between January 2012 and 2016. Patency was analyzed using the Kaplan–Meier method.

Results

Twenty-one patients received stent graft placement for CAS. Technical and clinical success rates were 100%. Primary target lesion patency was 95% (95% confidence interval [CI], 86%–100%), 76% (95% CI, 58%–94%), and 43% (95% CI, 22%–64%) at 3, 6, and 12 months, respectively. No significant difference in patency was observed between the arteriovenous fistula and arteriovenous graft groups. Assisted primary patency was 95% (95% CI, 86%–100%), 71% (95% CI, 52%–91%), and 57% (95% CI, 36%–78%) at 3, 6, and 12 months, respectively. Secondary patency was 100% at 3, 6, and 12 months.

Conclusions

After repeated failed angioplasty for cephalic arch stenosis, patients on hemodialysis who receive stent graft placement have effective and durable outcomes.

Advances in Endovascular Salvage

Endovascular salvage plays an important role in dialysis access care. Angioplasty using standard high- and ultrahigh-pressure balloon is the mainstay of therapy, while the use of cutting balloons and balloons designed to deliver pharmacologically active agents to the site of recurrent stenosis is demonstrating improved performance for specific targets that have to be further defined. Stents and stent grafts are additional tools for use at access segments predisposed for inward remodeling such as the cephalic arch or basilic swing point. The juxta-anastomotic segment has particular relevance in maturation of autogenous accesses as well as maintenance of access flow volume. Depending on the location of the access in the forearm or upper arm, and which artery is feeding into the access vein, any type of balloon angioplasty and stent or stent graft placement may be used to establish and maintain patency. Successful management of dialysis access options relies on preservation of venous real estate during the chronic kidney disease phase of kidney disease as well as on knowledgeable evaluation of arm veins and the access by physical examination, bed side ultrasound, and angiographic studies.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

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.

Factors influencing outcomes of rheolytic thrombectomy on thrombosed dialysis access grafts: Door to angiographic bed time and what else?

BACKGROUND

The aim of this study was to investigate the effect of the time interval from clinical presentation of arteriovenous graft thrombosis and the thrombectomy procedure by the AngioJet system in terms of technical and clinical success and to identify factors influencing success.

METHODS

A total of 60 consecutive patients (35 men and 25 women; mean age = 52 ± 7.89 years) who had undergone percutaneous thrombectomy by the AngioJet device from 2016 to 2019 were retrospectively enrolled. Demographics and fistula data, previous treatments, time from clinical onset of thrombosis to intervention, procedural details and complications were recorded. Technical and clinical success and primary and secondary patency rates were calculated. One-way analysis of variance was performed to test any correlation between patient-related and fistula/procedure-related variables and technical/clinical success. Odds ratio and relative risk were also calculated when necessary.

RESULTS

Technical success and clinical success were 95% and 91.7%, respectively. Post-interventional primary and secondary patency rates at 1 year were 72.5% and 84.3%, respectively. Complication rate was 6.7%. One-way analysis of variance showed that clinical success was higher in patients with no previous treatment (p = 0.015). Furthermore, clinical success was significantly associated with door to angiographic bed time (p = 0.002): p-value for the 24-h and the 72-h cut-off was 0.012 and 0.006, respectively.

CONCLUSION

Percutaneous rheolytic thrombectomy is safe and effective for thrombosed arteriovenous grafts, with acceptable primary and secondary patency rates. Higher clinical success was found in patients never treated before and when the procedure was carried out within 24 h from the clinical onset of thrombosis.

A retrospective comparison analysis of results of drug-coated balloon versus plain balloon angioplasty in treatment of juxta-anastomotic de novo stenosis of radiocephalic arteriovenous fistulas

BACKGROUND

Juxta-anastomotic stenosis is a common issue of arteriovenous fistulas. We aimed to evaluate the results of percutaneous transluminal angioplasty with drug-coated balloon versus plain balloon for the treatment of juxta-anastomotic stenoses of mature but failing distal radiocephalic arteriovenous fistulas.

METHODS

A total of 80 patients with a juxta-anastomotic stenosis of distal radiocephalic arteriovenous fistula in our clinic between January 2016 and September 2017 were retrospectively analyzed. Patients were divided into two groups according to the type of treatment as drug-coated balloon - percutaneous transluminal angioplasty (n = 44) and plain balloon - percutaneous transluminal angioplasty (n = 43). Intra- and post-procedural data were recorded. Target lesion primary patency rate was evaluated at 6 and 12 months. Of all patients, 48 were females and 39 were males with a mean age of 56.3 ± 10.4 (range, 24-75) years. Both groups had mature fistulas, and the mean age of fistula was 11.3 ± 9.1 months in the drug-coated balloon - percutaneous transluminal angioplasty group and 10.3 ± 8.8 months in the plain balloon - percutaneous transluminal angioplasty group (p = 0.24).

RESULTS

There was no significant difference in the target lesion stenosis rate and the median lesion length between the groups. Technical and clinical success were achieved in both groups. Target lesion primary patency was similar at 6 months between the two groups (93.1% vs 81.3%, respectively; p = 0.14) but significantly higher for the drug-coated balloon - percutaneous transluminal angioplasty group at 12 months (81.8% vs 51.1%, respectively; p = 0.01).

CONCLUSION

Our study results suggest that the use of drug-coated balloon combined with percutaneous transluminal angioplasty is an effective treatment for juxta-anastomotic stenoses of mature but failing distal radiocephalic arteriovenous fistulas with significantly improved target lesion primary patency rates and reduced need for juxta-anastomotic reinterventions.

Site of service influence on stent use for hemodialysis access interventions

OBJECTIVE

With rising health care spending in the United States, the Centers for Medicare and Medicaid Services (CMS) in recent years attempted to use reimbursement rates to influence use of less expensive care sites for covered patients, such as ambulatory surgery centers (ASCs) and office-based laboratories (OBLs), in lieu of hospital service sites. It has been suggested that cost savings have not been realized because of more procedures being performed by physicians with ownership interests in nonhospital facilities. CMS adopted massive reimbursement changes for 2019 OBL and ASC-based procedures, which reduced dialysis access angioplasty reimbursement in the ASC setting by 50%, whereas facility reimbursement for stenting increased by 33% above prior levels. The clinical utility of adjunctive stenting in treating dialysis access stenosis remains controversial and highly discretionary. As a vascular group performing such procedures in both a hospital and nonhospital facility in which we have equity interest, we reviewed our use of stents in dialysis access procedures both in the hospital and in the ASC/OBL to determine whether site of service affected stent use.

METHODS

A retrospective review of a prospectively maintained database was performed from 2014 to 2018. All patients undergoing dialysis access angiography with angioplasty and adjunctive stent placement at our OBL (later ASC) and our primary hospital were included in the study.

RESULTS

There were 961 angioplasty or stent procedures performed for dialysis accesses between the two sites, 564 (58.7%) in the hospital setting and 397 (41.3%) at the OBL/ASC. There was a significant difference in race and age between the two sites, with younger, minority patients more frequently being treated in the hospital and older, white patients more likely to be treated in the ambulatory setting; 153 (27.1%) underwent adjunctive stent placement in the hospital and 127 (32.0%) in the ambulatory setting (P = .09).

CONCLUSIONS

Whereas financial incentives have not yet had an appreciable influence on stent use for dialysis access within previous reimbursement paradigms, the dramatic changes recently adopted by CMS may well alter this dynamic and could lead to substantially higher overall costs without proven clinical advantage. Interventionalists may be incentivized to add stents when performing balloon angioplasty in ASCs. With high failure and reintervention rates and increasingly expensive adjuncts (drug-coated balloons and stents, covered stents), the cost implications of attempts to incentivize interventionalists toward a specific type of procedure or site of care are substantial, and unintended negative consequences are likely to occur.

Central venous disease in hemodialysis patients

Central venous disease (CVD) is difficult to treat and often resistant to treatment. In CVD, hemodialysis vascular access should sometimes be abandoned, or in serious cases, the patient's life may be threatened. Therefore, prevention is ideal. However, as the prevalence of chronic kidney disease (CKD) has increased steadily with population aging, CKD patients with a peripherally inserted central catheter (PICC) are encountered frequently. PICCs can cause CVD, and the basilic vein, which is regarded as the important last option for native arteriovenous fistula (AVF) creation in end-stage renal disease (ESRD) patients, is destroyed frequently after its use as the entry site of PICC. The most well-established risk factors for CVD are a history of central venous catheter (CVC) insertion and its duration of use. Therefore, to reduce the incidence of CVD, catheterization in the central vein (CV) should be minimized, along with its duration of use. In this review, we will first explain the basic territories of the CV and introduce its pathophysiology, clinical features, and advanced treatment options. Finally, we will emphasize prevention of CVD.

Treatment of failing arterio-venous dialysis graft by angioplasty, stent, and stent graft: Two-years analysis of patency rates and cost-effectiveness

The objective of this prospective randomized single-center study was to compare primary and secondary patency rates, number of percutaneous transluminal angioplasty (PTA) interventions and cost-effectiveness among PTA, deployment of a stent, or a stent graft in the treatment of failing arteriovenous dialysis grafts (AVG) due to restenosis in the venous anastomosis or the outflow vein. Altogether 60 patients with failing AVG and restenosis in the venous anastomosis or the outflow vein were randomly assigned to either PTA, placement of a stent (E-Luminexx^®) or stent graft (Fluency Plus^®). After the procedure, patients with stent or stent graft received dual antiplatelet therapy for the next three months. Follow-up angiography was scheduled at 3, 6, and 12 months unless requested earlier due to suspected stenosis or malfunction of the access. Subsequently, angiography was performed only if requested by the clinician. During a median follow-up of 22.4 (IQR=5.7) months patients with PTA, stent, or stent graft required 3.1±1.7, 2.5±1.7, or 1.7±2.1 (P=0.031) secondary PTA interventions. The primary patency rates were 0, 18 and 65% at 12 months and 0, 18 and 37% at 24 months in the PTA, stent, and stent graft group respectively (P<0.0001). The cost of the procedures in the first two years was €7,900±€3,300 in the PTA group, €8,500±€4,500 in the stent group, and €7,500±€6,200 in the stent graft group (P=0.45). We conclude that the treatment of failing dialysis vascular access by the deployment of a stent graft significantly improves its primary patency rates and decreases the number of secondary PTA interventions; however, the reduction in costs for maintaining AVG patency is not significant.

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.

Outcomes of endovascular salvage of clotted arteriovenous access and predictors of patency after thrombectomy

OBJECTIVE

This study aimed to report the outcomes of endovascular salvage of clotted arteriovenous (AV) accesses and to determine potential predictors of poor patency rates after thrombectomy.

METHODS

Records of hemodialysis patients who underwent endovascular salvage of clotted AV access were reviewed retrospectively. Technical and clinical success rates, complication rates, and 3- and 6-month patency rates were determined. Multivariate analysis was performed to determine the predictors of patency after thrombectomy.

RESULTS

A total of 294 patients underwent endovascular salvage of clotted AV access during the study period; 156 patients had arteriovenous fistula, whereas the remaining 138 were arteriovenous grafts (AVGs). The technical and clinical success rates were 96.3% and 93.2%; the major and minor complication rates were 0.7% and 9.9%. Post-thrombectomy primary, assisted primary, and secondary patency rates were 62.9%, 76.2%, and 77.6% at 3 months and 43.9%, 59.5%, and 61.6% at 6 months. The patency rates were significantly better for arteriovenous fistula than for AVG except for 6-month assisted primary and secondary patency. Multivariate Cox regression analysis showed that prior thrombosis within 90 days was significantly associated with loss of primary patency (hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.21-2.98; P < .01), assisted primary patency (HR, 2.42; 95% CI, 1.42-4.13; P < .01), and secondary patency (HR, 2.52; 95% CI, 1.40-4.53; P < .01). Having an AVG was also negatively associated with primary patency.

CONCLUSIONS

Most clotted AV accesses can be salvaged by endovascular technique. Recurrent thrombosis within 90 days is associated with poor short- and long-term patency even after successful endovascular reinterventions.

A randomized feasibility study of the effect of ascorbic acid on post-angioplasty restenosis of hemodialysis vascular access (NCT03524846)

Restenosis remains a significant problem after angioplasty of hemodialysis vascular access. Both experimental and clinical studies have shown a protective effect of antioxidants against post-angioplasty restenosis. A prospective, randomized, feasibility study was conducted to investigate the effect of ascorbic acid to prevent restenosis. Ninety-three hemodialysis patients were randomized into three groups after angioplasty: placebo (n = 31), 300 mg ascorbic acid (n = 31), and 600 mg ascorbic acid (n = 31), treated intravenously 3 times per week for 3 months. Eighty-nine completed the clinical follow-up, and 81 had angiographic follow-up. In the angiographic follow-up, the mean (stand deviation) late loss of luminal diameter for the placebo, 300 mg, and 600 mg groups were 3.15 (1.68) mm, 2.52 (1.70) mm (P = 0.39 vs. placebo group), and 1.59 (1.67) mm (P = 0.006, vs. placebo group), with corresponding angiographic binary restenosis of 79%, 67% (P = 0.38 vs. placebo group), and 54% (P = 0.08 vs. placebo group). The post-interventional primary patency rates at 3 months were 47%, 55% (P = 0.59 vs. placebo group), and 70% (P = 0.18 vs. placebo group) for placebo, 300 mg, and 600 mg groups. Our results demonstrated that intravenous 600 mg ascorbic acid was a feasible therapy and might attenuate restenosis after angioplasty; however, its effect on post-interventional primary patency was modest.

Septic embolization from stented arteriovenous fistula

Anastomotic stenosis of an arteriovenous fistula is often amenable to percutaneous intervention (angioplasty and stenting) and unlikely to be complicated by infection. A 69-year-old man underwent pre-emptive arteriovenous fistula construction that required interval placement of a covered stent for juxta-anastomotic stenosis. The patient presented 1 year after the intervention with systemic sepsis that required stent graft explantation and revision. This is a unique case report showing an infected stent graft, placed to restore secondary patency, that was later found to be the source of bacteremia and septic pulmonary emboli.

Stent Graft Placement for Treatment of Prosthetic Graft Outflow Stenosis, a Viable Long-term Solution: A Case Report

Failing prosthetic grafts in patients undergoing hemodialysis is a common problem. Balloon angioplasty is the first line in treating these stenoses, but it is associated with poor patency rates due to recoil and subsequent restenosis. The use of stent graft implantation has shown very promising early and long-term results as per recent literature. We describe a case of arteriovenous graft outflow stenosis, which led to complete thrombosis of the graft, which was rescued by surgical thrombectomy and stent graft placement across the venous end of the anastomosis with good results.

Clinical and Economic Benefits of Stent Grafts in Dysfunctional and Thrombosed Hemodialysis Access Graft Circuits in the REVISE Randomized Trial

PURPOSE

To compare reinterventions and associated costs to maintain arteriovenous graft hemodialysis access circuits after rescue with percutaneous transluminal angioplasty (PTA), with or without concurrent Viabahn stent grafts, over 24 months.

MATERIALS AND METHODS

This multicenter (n = 30 sites) study evaluated reintervention number, type, and cost in 269 patients randomized to undergo placement of stent grafts or PTA alone. Outcomes were 24-month average cumulative number of reinterventions, associated costs, and total costs for all patients and in 4 groups based on index treatment and clinical presentation (thrombosed or dysfunctional).

RESULTS

Over 24 months, the patients in the stent graft arm had a 27% significant reduction in the average number of reinterventions within the circuit compared to the PTA arm (3.7 stent graft vs 5.1 PTA; P = .005) and similar total costs ($27,483 vs $28,664; P = .49). In thrombosed grafts, stent grafts significantly reduced the number of reinterventions (3.7 stent graft vs 6.2 PTA; P = .022) and had significantly lower total costs compared to the PTA arm ($30,329 vs $37,206; P = .027). In dysfunctional grafts, no statistical difference was observed in the number of reinterventions or total costs (3.7 stent graft vs 4.4 PTA; P = .12, and $25,421 stent graft and $22,610 PTA; P = .14).

CONCLUSIONS

Over 24 months, the use of stent grafts significantly reduced the number of reinterventions for all patients, driven by patients presenting with thrombosed grafts. Compared to PTA, stent grafts reduced overall treatment costs for patients presenting with thrombosed grafts and had similar costs for stenotic grafts.

[Long-term results of chest wall arteriovenous graft for establishing hemodialysis access]

Objective

To explore the role of chest wall arteriovenous graft (CWAVG) for establishing hemodialysis access in patients with end-stage renal disease.

Methods

A retrospective analysis was made on the clinical data of 12 patients with end-stage renal disease who underwent CWAVG for establishing hemodialysis access between January 2014 and June 2015. There were 3 males and 9 females with an average age of 63.6 years (range, 54-82 years). The renal disease causes were chronic glomerulonephritis in 2 cases, hypertensive renal damage in 4 cases, diabetic nephropathy in 1 case, both kidney resection because of urinary tract tumors in 3 cases, and causes unknown in 2 cases. Hemodialysis time ranged from 1 to 144 months, with an average of 38.4 months. The 12 patients all underwent 1-14 times (mean, 4.2 times) anterior pathway failure in CWAVG, all of which were caused by repeated occlusion of dialysis pathway or poor vascular condition of upper extremity, resulting in the exhaustion of vascular pathway in upper extremity.

Results

All patients were followed up 30-48 months (mean, 35.4 months). Two patients died, including 1 case of digestive tract hemorrhage, 1 case of heart failure. The other 10 CWAVGs were functionally useful for hemodialysis access about 6 weeks after operations. The primary patency rates at 6, 12, 18, 24, and 30 months were 83.3%, 75.0%, 33.3%, 33.3%, and 16.7%, respectively, and the cumulative patency rates at 6, 12, 18, 24, and 30 months were 83.3%, 75.0%, 50.0%, 33.3%, and 16.7%, respectively. Among 8 cases of CWAVG dysfunction, 6 cases had thrombosis, 1 case had seroma, and 1 case had vertebral artery stealing. Among them, 4 patients underwent hemodialysis using tunneled-cuffed catheter, 3 patients using fistula or graft on other limbs, and 1 patient was not treated with hemodialysis.

Conclusion

Although the long-term patency rate of CWAVG is yet to be further increased by improvement of treatment strategies, but it is still a supplementary option for end-stage renal disease patients with inadequate upper extremity venous access sites.

Hybrid salvage of thrombosed dialysis access grafts

BACKGROUND

To report our experience and evaluate the results of a hybrid procedure comprising of surgical thrombectomy and adjuvant high pressure balloon angioplasty for management of thrombosed arteriovenous grafts (AVGs) with underlying venous anastomotic stenosis.

METHODS

Between January 2015 and June 2017, 148 patients with first-time thrombosis of AVGs were considered for treatment with surgical thrombectomy followed by high pressure balloon angioplasty of the underlying venous anastomotic lesions. Monitoring and surveillance was subsequently performed using clinical and hemodialysis criteria to detect a failing/failed access. Primary, assisted primary, and secondary patency rates were calculated using Kaplan-Meier analysis.

RESULTS

This hybrid procedure was technically successful in 135 cases (91.2%) and clinically successful in 131 cases (88.5%). The postintervention primary patency rate of the target lesions was 68.2%, 52.4%, and 44.2% at 3, 6, and 12 months, respectively. Endovascular re-interventions increased significantly the postintervention assisted primary patency to 79.1%, 71.9%, and 66.8% (P=0.0004), and the postintervention secondary patency to 86.5%, 82.2%, and 78.6% (P<0.0001) at the same time points, respectively.

CONCLUSIONS

Hybrid salvage of thrombosed AVGs using high pressure balloon angioplasty of the venous anastomotic stenosis following surgical thrombectomy by Fogarty catheter is a highly successful and safe procedure, with acceptable short-term primary patency. The need for repeated interventions demonstrates the necessity of continuous graft monitoring and surveillance to improve both assisted primary, and secondary patency rates.

Revision Using Distal Inflow for the Treatment of Dialysis Access Steal Syndrome: A Systematic Review

The aim of this systematic review is to establish the efficacy of revision using distal inflow (RUDI) on the primary endpoints of complete dialysis access steal syndrome (DASS) resolution and arteriovenous fistula (AVF) longevity. An electronic search of literature from 1966 to 2017 in CINAHL, Medline, Embase and the Cochrane library according to PRISMA standards was conducted. Quality evaluations and recommendations for practice were examined. Data on power, age, gender, comorbidities, arterial inflow, conduit material, fistulae type, follow-up, failure incidence, ischaemia grade, modality of diagnosis, morbidity and mortality were subjected to pooled analysis of prevalence at a 95% confidence interval (CI). Eleven studies involving 130 individuals with a median age of 57 [interquartile ranges (IQR), 54-65] and equal gender distribution were conducted. Of the patients with diabetes mellitus (67.3%), the most common type of AVF with DASS was brachiocephalic AVF (73.7%). Overall, the prevalence of success was 82.0% (95%CI, 74.4%-89.6%) over 12 months (IQR, 1-40 months). Grade 3 ischaemia was the most common type of DASS (49.2%). Grade 4 had the worst outcomes compared with grades 2 and 3. The overall morbidity was 3% with no mortality. Overall, RUDI is an effective treatment for various grades of DASS and their longevity.

Clinical Evaluation of the Cook Advance Enforcer 35 Focal-Force PTA Balloon Catheter for Treatment of Hemodialysis Fistula Stenoses: A Feasibility Study

PURPOSE

A prospective, single-center, single-arm feasibility study evaluated procedural and short-term performance of the Advance Enforcer 35 focal-force percutaneous transluminal angioplasty (PTA) balloon catheter in treating stenoses of mature native arteriovenous (AV) hemodialysis access circuits.

MATERIALS AND METHODS

Twenty-eight patients undergoing treatment for stenosis of a mature native AV hemodialysis access circuit were enrolled at a single institution. Angiographic assessments of the study lesion were required at baseline and after the procedure. Adjunctive procedures for significant residual stenosis were permitted, and patients had clinical and imaging follow-up for as long as 6 months.

RESULTS

Treatment with the study balloon was effective in reducing the average percent diameter stenosis of the treated lesion from 66.3% (range, 43.8%-93.3%) before the procedure to 23.7% (range, -6.7% to 51.4%) after the procedure. The average inflation pressure required was 12.3 atm. Only 1 patient required an adjunctive procedure, and all patients could resume normal dialysis following the study procedure. At 3 months, 62.0% of study lesions remained patent, and the 6-month patency rate was 25.1%. Two adverse events associated with the study procedure were reported: access-site hematoma and forearm pain (3.6% each).

CONCLUSIONS

The results demonstrate safety of the study balloon in treating AV access stenosis. Nominal-diameter angioplasty was achieved at relatively low pressure in most study patients without the use of adjunctive procedures, and resumption of normal dialysis was achieved for all patients.

Recent developments in endovascular interventions to sustain vascular access patency in haemodialysis patients

There is amassed evidence regarding the use of endovascular procedures for the treatment of vascular access stenosis and thrombosis. A review was conducted based on available randomized trials, cohort studies and retrospective analyses published after 2000 on endovascular treatment of dysfunctional and thrombosed vascular access, with an aim to illustrate the available device and procedural options. The use of paclitaxel-coated balloons, cutting balloons and covered stents is described in the field of vascular access stenosis. The broad spectrum of available devices and endovascular declotting procedures ranging from thrombolysis to thrombectomy is also discussed. Overall, in this review we demonstrate the increasing role of endovascular procedures in vascular access treatment and the improved patency outcomes provided by the implementation of novel endovascular devices. Moreover, the improvement of post-intervention primary patency rates after endovascular declotting procedures and the shift to more thrombectomy-dependent procedures over time is also highlighted. In conclusion, endovascular treatment of dialysis access stenosis and thrombosis has an established role, owing to the implementation of sophisticated devices, allowing, when needed, the simultaneous treatment of thrombosis and the underlying stenosis.

Outcomes of endovascular treatments for in-stent restenosis in patients with mesenteric atherosclerotic disease

OBJECTIVE

Mesenteric angioplasty and stenting (MAS) has surpassed open revascularization as the treatment of choice for mesenteric ischemia. Despite the lower perioperative mortality associated with MAS, the need for reintervention is not infrequent. The purpose of this study was to review the outcomes of patients treated for mesenteric artery in-stent restenosis (MAISR).

METHODS

Clinical data from a single center between 2004 and 2017 were retrospectively analyzed. Standard statistical analysis including Kaplan-Meier estimate for time-dependent outcomes, χ² test for categorical variables, and two-sample t-test for continuous variables was performed. Primary end points included stent patency and reintervention rate. Secondary end points included mortality and morbidity.

RESULTS

During the study period, 91 patients underwent primary MAS. In total, 113 mesenteric vessels were treated with 20 covered stents and 93 bare-metal stents. Overall primary patency was 69% at 2 years. At 2 years, primary patency was 83% for covered stents compared with 65% for bare-metal stents (P = .17). Of these 91 primary MAS patients, 27 (30%) were treated for MAISR (32 vessels). Two covered stent patients developed significant restenosis (11%) compared with 25 (34%) bare-metal stent patients (P = .02). The mean age of patients requiring reintervention was 69 years (36% male), with the majority having a history of tobacco use (85%), hypertension (75%), and hyperlipidemia (78%). Fourteen reintervention patients (52%) presented with recurrent symptoms, 10 (37%) had asymptomatic restenosis, and 3 (11%) developed intestinal ischemia. Twelve patients (44%) underwent reintervention with balloon angioplasty alone and 15 (56%) underwent repeated stent placement. Of the 15 patients who had repeated stent placement, 7 patients had covered stents placed. The 30-day mortality rate after reintervention for mesenteric stent restenosis was 0%. Postoperative complications occurred in 15% of patients (myocardial infarction, 4%; reversible kidney injury, 4%; and bowel ischemia requiring surgical exploration, 7%). There was no difference in the perioperative morbidity in comparing symptomatic and asymptomatic patients undergoing reintervention. Mean follow-up after mesenteric reintervention was 31 months, with one-third of patients (n = 9) requiring another reintervention because of either recurrence of symptoms or asymptomatic high-grade restenosis. Assisted primary patency at 2 years was 92% after reintervention with balloon angioplasty and 87% for repeated stent placement, with no statistically significant difference between the groups (P = .66).

CONCLUSIONS

Treatment of MAISR is associated with low mortality and acceptable morbidity. The initial use of covered stents may reduce the need for reintervention.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

An Economic Analysis of Stent Grafts for Treatment of Vascular Access Stenosis: Point-of-Care and Medicare Perspectives in the United States

PURPOSE

To conduct an economic analysis on the impact of increased stent graft (SG) use for treatment of arteriovenous graft (AVG) anastomotic stenosis or arteriovenous fistula (AVF)/AVG in-stent restenosis (ISR) from United States point-of-care (POC) and Medicare perspectives.

MATERIALS AND METHODS

The analyses compared initial device and reintervention costs over 2 years between current and projected treatment mixes, including percutaneous transluminal angioplasty (PTA), bare metal stents (BMSs), and SGs. In projected scenarios, the absolute increase in SG use was approximately 3%. Costs included procedure reimbursement rates (Medicare) and device list prices (POC) for index procedures and reinterventions. Reintervention rates and types were informed by the RENOVA and RESCUE randomized trials. Reinterventions were primarily PTA only; however, stent use occurred a proportion of the time. BMS reintervention rates were assumed to be identical to PTA based on observational data. A population size of 1,000 patients was assumed.

RESULTS

To the POC (n = 1,000), increased SG use was predicted to result in cost savings ranging from $4,106 to $34,420 for AVG anastomotic stenosis. For AVF/AVG ISR, increased SG use was predicted to result in either a cost increase of $17,187 or a cost savings of $13,159. To Medicare (n = 1,000), increased SG use was predicted to save costs for both populations, with savings ranging from $57,401 to $169,544.

CONCLUSIONS

The use of SG for treatment of AVG anastomotic stenosis and AVF/AVG ISR appears to be economically favorable for POC providers and Medicare. Further data on reintervention rates are required from other SG trials to validate findings.

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.

A survival guide for endovascular declotting in dialysis access: procedures, devices, and a statistical analysis of 3,000 cases

INTRODUCTION

Thrombosis is the most important access-related complication. Several declotting procedures have been suggested falling mainly into two categories; thrombolysis-dependent and thrombectomy-dependent.

AREAS COVERED

Seventeen studies after 2001 have been published on percutaneous treatment of thrombosed vascular access. Authors performed a systematic review of these studies together with a parametric meta-analysis of data available investigating clinical success, postintervention assisted primary patency (PAPP) and independent factors that could influence outcome measures.

EXPERT COMMENTARY

A shift to thrombectomy-dependent procedures is observed with a view to diminishing complications from the use of thrombolytic agents. Arteriovenous fistulas provide significantly better PAPP, while newer studies show improved, non-significant results compared with older ones. The role of improvement of devices for subsequent angioplasty is of equal importance, if not more, for improved declotting results.

Role of stents in hemodialysis vascular access

Stents are ubiquitously utilized in coronary and peripheral arterial disease. Interventional nephrologists, however, place stents in the venous outflow of the arteriovenous access. Stenosis is the predominant pathology that causes access dysfunction and will ultimately lead to thrombosis if uncorrected. Angioplasty and stent deployment are the current techniques available to combat stenosis. From initial bare metal stainless steel stents, the current generations of stents used are predominately covered nitinol stents. The latest randomized control trials reveal that stents decrease the number of interventions required to maintain patency but do not improve the overall access survival. Furthermore, bare metal stents have been shown to be inferior to stent grafts. This review discusses indications for stent deployment in the hemodialysis access, the current evidence for their use, and briefly touches on their complications.

Definitions and End Points for Interventional Studies for Arteriovenous Dialysis Access

This paper is part of the Clinical Trial Endpoints for Dialysis Vascular Access Project of the American Society of Nephrology Kidney Health Initiative. The purpose of this project is to promote research in vascular access by clarifying trial end points which would be best suited to inform decisions in those situations in which supportive clinical data are required. The focus of a portion of the project is directed toward arteriovenous access. There is a potential for interventional studies to be directed toward any of the events that may be associated with an arteriovenous access' evolution throughout its life cycle, which has been divided into five distinct phases. Each one of these has the potential for relatively unique problems. The first three of these correspond to three distinct stages of arteriovenous access development, each one of which has been characterized by objective direct and/or indirect criteria. These are characterized as: stage 1-patent arteriovenous access, stage 2-physiologically mature arteriovenous access, and stage 3-clinically functional arteriovenous access. Once the requirements of a stage 3-clinically functional arteriovenous access have been met, the fourth phase of its life cycle begins. This is the phase of sustained clinical use from which the arteriovenous access may move back and forth between it and the fifth phase, dysfunction. From this phase of its life cycle, the arteriovenous access requires a maintenance procedure to preserve or restore sustained clinical use. Using these definitions, clinical trial end points appropriate to the various phases that characterize the evolution of the arteriovenous access life cycle have been identified. It is anticipated that by using these definitions and potential end points, clinical trials can be designed that more closely correlate with the goals of the intervention and provide appropriate supportive data for clinical, regulatory, and coverage decisions.

Vascular Tissue Engineering: Progress, Challenges, and Clinical Promise

Although the clinical demand for bioengineered blood vessels continues to rise, current options for vascular conduits remain limited. The synergistic combination of emerging advances in tissue fabrication and stem cell engineering promises new strategies for engineering autologous blood vessels that recapitulate not only the mechanical properties of native vessels but also their biological function. Here we explore recent bioengineering advances in creating functional blood macro and microvessels, particularly featuring stem cells as a seed source. We also highlight progress in integrating engineered vascular tissues with the host after implantation as well as the exciting pre-clinical and clinical applications of this technology.

Stent graft placement versus angioplasty for hemodialysis access failure: a meta-analysis

BACKGROUND

Hemodialysis is a common treatment for end-stage renal disease, and maintenance of access patency remains a key issue. Angioplasty is recommended as the first choice for access stenosis, but it poses a risk of a high rate of restenosis. Stent graft placement can generate a high patency rate of dialysis access. This study aimed to compare the primary patency of the treatment area and access circuit between stent grafts and angioplasty in dialysis access failure.

MATERIALS AND METHODS

Three electronic databases, namely, PubMed, Cochrane Library of Systematic Reviews, and EMBASE, were searched from the database inception to September 2017 without language restriction. Randomized controlled trials comparing the primary patency of the treatment area and access circuit between stent graft and angioplasty were included. Two independent reviewers assessed the quality of the trials and extracted relevant data.

RESULTS

Four trials satisfied our inclusion criteria. Our pooled results suggested that stent graft placement was associated with significantly higher primary patency of treatment area (hazard ratio: 0.65, 95% confidence interval: 0.55-0.77, P < 0.0001, I² = 0) and access circuit (hazard ratio: 0.76, 95% confidence interval: 0.65-0.88, P = 0.0004, I² = 0) in hemodialysis access compared with those of standard angioplasty.

CONCLUSIONS

The patency of hemodialysis access may be higher after stent graft placement combined with standard angioplasty than after angioplasty alone.

Stent Graft versus Balloon Angioplasty for Failing Dialysis Access Grafts: A Long-Awaited Advance in the Treatment of Permanent Hemodialysis Access

Arteriovenous grafts (AVGs) for hemodialysis have a high failure rate, often due to the development of stenosis at the graft-to-vein anastomosis. Angioplasty (PTA) has been used for over two decades to treat AVG stenosis, with good technical success but limited AVG patency. Results of a prospective multi-center randomized trial, comparing stent graft to PTA in AVGs, has demonstrated superior access circuit patency for the stent graft group. Recent publication of this clinical study brings us into an exciting new era of dialysis access management using covered stents to improve durability of catheter-based therapy.

Impact of Lesion Morphology on Durability After Angioplasty of Failed Arteriovenous Fistulas in Hemodialysis Patients

PURPOSE

To investigate if morphological patterns of arteriovenous fistula (AVF) venous lesions affect primary patency after percutaneous transluminal angioplasty (PTA).

METHODS

From July 2014 to June 2015, 262 patients underwent PTA for failed AVFs. A total of 104 patients were excluded owing to (1) calcification or AVF occlusion precluding ultrasound examination, (2) central venous or arterial lesions, and (3) no follow-up, leaving 158 patients (mean age 71±12; 96 men) for analysis. More than half of the patients had one or more previous PTAs for the failed AVF. Prior to PTA the stenotic lesions were assessed using ultrasonography to determine stenotic patterns at the minimum lumen area site and to evaluate the flow volume in the brachial artery. Three stenotic patterns were identified: intimal hyperplasia (IH) stenosis (n=110), shrinking lumen stenosis (n=32), and venous valve-related stenosis (n=16). The main outcome measure was primary patency after PTA estimated using Kaplan-Meier analysis. Predictors for loss of primary patency were determined using a multivariate Cox proportional hazards model; the results are presented as the adjusted hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

Median follow-up after PTA was 6.3 months (interquartile range 3.3, 10.5). The 6-month primary patency estimates were 56%±5% in the IH group, 40±9% in the shrinking lumen group, and 100% in the valve stenosis group (IH vs shrinking, p=0.013; IH vs valve, p=0.003). In multivariate analysis, shrinking lumen morphology had a negative impact on primary patency (HR 2.05, 95% CI 1.25 to 3.36, p=0.005), while venous valve-related stenosis had a positive impact (HR 0.19, 95% CI 0.04 to 0.79, p=0.023). Flow volume (10-mL/min increments; HR 0.97, 95% CI 0.96 to 0.99, p=0.004) and history of PTA (HR 1.66, 95% CI 1.06 to 2.60, p=0.029) were also independently associated with primary patency after PTA.

CONCLUSION

The patterns of AVF stenosis as determined by ultrasound can affect the outcome of treatment with balloon dilation.

Balloon Angioplasty Versus Stenting for the Treatment of Failing Arteriovenous Grafts: A Meta-Analysis

PURPOSE

To assess the outcomes of plain balloon angioplasty versus stenting for the treatment of failed or malfunctioning chronic haemodialysis arteriovenous grafts (AVGs).

METHODS

A systematic search of the literature was undertaken using the PUBMED, EMBASE, and Cochrane databases from January 2000 to September 2016 for articles comparing balloon angioplasty versus stenting in the management of failed or malfunctioning chronic haemodialysis AVGs. Results are reported as OR and 95% CI.

RESULTS

The search identified eight studies (1051 patients). Balloon angioplasty alone was used in 521 patients (49.6%) and stenting in 530 patients (50.4%). At the time of the endovascular re-intervention, the mean life of AVGs was 807.7±115.4 days for the balloon angioplasty and 714.2±96.3 days for the stenting group (p=.92). All AVGs were located in the arm. Most procedures (98.1%) were performed across the venous anastomosis, while 88% of the patients in the stenting group received a stent graft. The technical success rate was significantly higher in the stenting group (OR 0.16, 95% CI 0.08-0.31, p<.001). At 12 months, loss of primary and secondary patency was significantly higher in patients undergoing plain balloon angioplasty compared with stenting (OR 3.54, 95% CI 2.18-5.74, p<.001, and OR 1.82, 95% 1.17-2.82, p=.008, respectively).

CONCLUSION

Stenting is associated with better technical success and patency rates compared with plain angioplasty in treating failed or malfunctioning chronic haemodialysis AVGs, and thus it should be considered as the first line therapeutic option.