Paclitaxel-coated balloon fistuloplasty versus plain balloon fistuloplasty only to preserve the patency of arteriovenous fistulae used for haemodialysis (PAVE): study protocol for a randomised controlled trial

Circulating Interleukin-6 and CD16 positive monocytes increase following angioplasty of an arteriovenous fistula

Arteriovenous fistulas are the ideal form of vascular access that allows provision of haemodialysis. Stenotic lesions caused by neointimal hyperplasia commonly occur resulting in patients requiring a fistuloplasty. This is effective but there is a high recurrence rate. We sought to investigate the effects of a fistuloplasty on monocyte populations. Blood samples were taken from patients before and after their fistuloplasty procedure. Samples were analysed using flow cytometry, ELISA and Luminex assays. Univariate cox regression was carried out to investigate associations with post fistuloplasty patency. At 1-2 days post fistuloplasty, the proportion of classical (CD14++CD16-) monocytes decreased (p < 0.001), whilst intermediate (CD14++CD16+) and non-classical (CD14+CD16+) monocytes increased (both p < 0.01) in a cohort of 20 patients. A time course study carried out in 5 patients showed that this was due to an increase in absolute numbers of non-classical and intermediate monocytes. Higher levels of non-classical monocytes pre-fistuloplasty were associated with an increased risk for patency loss (p < 0.05). We measured 41 soluble factors in plasma samples taken before a fistuloplasty in 54 patients, with paired post-fistuloplasty samples (1-2 days) available in 30 patients. After correcting for false discovery, the only factor with a significant change in level was IL-6 (P = 0.0003, q = 0.0124). In a further time-course study in 6 patients, peak level of IL-6 occurred 2-3 h post fistuloplasty. This study demonstrates that there is a systemic inflammatory response to the fistuloplasty procedure and that monocyte subsets and IL-6 may be important in the pathophysiology of restenosis.

Procedure and Clinical Success of Drug-Coated Balloon Fistuloplasty of the Drainage Vein in Dysfunctional Native Arteriovenous Fistulas

Purpose

Native arteriovenous fistulas (AVFs) are the most effective vascular access (VA) for haemodialysis. We aimed to evaluate the results of balloon angioplasty (fistuloplasty) from drainage vein performed for the treatment of AVF dysfunction in haemodialysis patients and examine potential patient and AVF-associated factors that might affect such results.

Methods

This is a nonrandomized, retrospective, and single-centred study. A total of 105 balloon fistuloplasties were performed for dysfunctional AVFs of 82 haemodialysis patients. Patients were treated with a drug-coated balloon according to standard procedures. Evaluations were performed by physical examinations and if needed by color Doppler imaging in every 6 months. The primary endpoint was patency by balloon fistuloplasty. Patency was evaluated clinically by detecting the thrill in AVF and by the adequacy of the dialysis. Multidimensional scaling (MDS) technique was used as a method for the statistical analysis.

Results

The success of the procedure after the first attempt was 85.3% with 70 patients. Patency in the 6th, 12th, 18th, and 24th months were 63 (76.8%), 60 (73.1%), 53 (64.6%), and 44 (54%), respectively. The procedure was considered successful when the thrill was detected in AVF and when dialysis was adequate. The statistical analysis by MDS revealed that patients' age was the most effective factor acting on the procedure success followed by the age of AVF. Other patient-associated and AVF-associated factors were not found as effective statistical evaluation.

Conclusions

Haemodialysis through native AVFs with restored functionality contributes positively to the life span and the quality of life of the patient. Probably, advanced age and high fistula age are unfavourable factors leading to the development of neointimal hyperplasia and venous stenosis. Balloon fistuloplasty of the draining vein is an effective and safe method regardless of patient age and the age of AVF.

Trends in Adaptive Design Methods in Dialysis Clinical Trials: A Systematic Review

Rationale & Objective

Adaptive design methods are intended to improve the efficiency of clinical trials and are relevant to evaluating interventions in dialysis populations. We sought to determine the use of adaptive designs in dialysis clinical trials and quantify trends in their use over time.

Study Design

We completed a novel full-text systematic review that used a machine learning classifier (RobotSearch) for filtering randomized controlled trials and adhered to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines.

Setting & Study Populations

We searched MEDLINE (PubMed) and ClinicalTrials.gov using sensitive dialysis search terms.

Selection Criteria for Studies

We included all randomized clinical trials with patients receiving dialysis or clinical trials with dialysis as a primary or secondary outcome. There was no restriction of disease type or intervention type.

Data Extraction & Analytical Approach

We performed a detailed data extraction of trial characteristics and a completed a narrative synthesis of the data.

Results

57 studies, available as 68 articles and 7 ClinicalTrials.gov summaries, were included after full-text review (initial search, 209,033 PubMed abstracts and 6,002 ClinicalTrials.gov summaries). 31 studies were conducted in a dialysis population and 26 studies included dialysis as a primary or secondary outcome. Although the absolute number of adaptive design methods is increasing over time, the relative use of adaptive design methods in dialysis trials is decreasing over time (6.12% in 2009 to 0.43% in 2019, with a mean of 1.82%). Group sequential designs were the most common type of adaptive design method used. Adaptive design methods affected the conduct of 50.9% of trials, most commonly resulting in stopping early for futility (41.2%) and early stopping for safety (23.5%). Acute kidney injury was studied in 32 trials (56.1%), kidney failure requiring dialysis was studied in 24 trials (42.1%), and chronic kidney disease was studied in 1 trial (1.75%). 27 studies (47.4%) were supported by public funding. 44 studies (77.2%) did not report their adaptive design method in the title or abstract and would not be detected by a standard systematic review.

Limitations

We limited our search to 2 databases (PubMed and ClinicalTrials.gov) due to the scale of studies sourced (209,033 and 6,002 results, respectively).

Conclusions

Adaptive design methods are used in dialysis trials but there has been a decline in their relative use over time.

Drug-coated balloon angioplasty for failing haemodialysis access: meta-analysis of randomized clinical trials

BACKGROUND

Arteriovenous fistulas, a major treatment for end-stage kidney disease, frequently require endovascular reinterventions to maintain haemodialysis function. Drug-coated angioplasty balloons (DCBs) were developed with the intention of reducing reintervention rates. The aim of this study was to perform a systematic review and meta-analysis of DCBs in the treatment of failing haemodialysis access.

METHODS

Electronic databases were searched systematically to identify all relevant RCTs and any follow-up studies from RCTs. Pooled estimates of dichotomous outcomes were calculated using the odds ratio (OR) and 95 per cent confidence interval. Effect data are presented as summary hazard ratio and 95 per cent confidence interval.

RESULTS

Some 19 studies from 18 RCTs and comprising 1898 patients were included in the meta-analysis. Compared with plain balloon angioplasty (PBA), DCB use was associated with higher target-lesion primary patency (HR 0.60, 95 per cent c.i. 0.45 to 0.79), access-circuit primary patency (HR 0.67, 0.56 to 0.80), and less target-lesion revascularization (TLR) within 6 months (OR 0.33, 0.23 to 0.47). No difference was observed between DCB and PBA in 12-month TLR (OR 0.62, 0.28 to 1.37). Mortality after DCB use was similar to that associated with PBA use at 6 months (OR 1.20, 0.65 to 2.21) and 12 months (OR 0.99, 0.66 to 1.49), and was higher at 24 months (23.1 versus 16.6 per cent), although the difference was not statistically significant (OR 1.53, 0.92 to 2.53).

CONCLUSION

Drug-coated balloon angioplasty of haemodialysis fistulas is associated with higher patency rates and lower rates of reintervention in the short to mid term. Although mortality rates appeared to be higher with drug-coated angioplasty at 24 months, this did not reach statistical significance.

A multicenter randomized controlled trial indicates that paclitaxel-coated balloons provide no benefit for arteriovenous fistulas

The role of paclitaxel-coated balloons has been established in the coronary and peripheral arterial circulations with recent interest in the use of paclitaxel-coated balloons to improve patency rates following angioplasty of arteriovenous fistulas. To assess the efficacy of paclitaxel-coated angioplasty balloons to prolong the survival time of target lesion primary patency in arteriovenous fistulas, we designed an investigator-led multi-center randomized controlled trial with follow up time variable for a minimum of one year. Patients with an arteriovenous fistula who were undergoing an angioplasty for a clinical indication were included but patients with one or more lesions outside the treatment segment were excluded. Following successful treatment with a high-pressure balloon, 212 patients were randomized. In the intervention arm, the second component was insertion of a paclitaxel-coated balloon. In the control arm, an identical procedure was followed, but using a standard balloon. The primary endpoint was time to loss of clinically driven target lesion primary patency. Primary analysis showed no significant evidence for a difference in time to end of target lesion primary patency between groups: hazard ratio 1.18 with a 95% confidence interval of 0.78 to 1.79. There were no significant differences for any secondary outcomes, including patency outcomes and adverse events. Thus, our study demonstrated no evidence that paclitaxel-coated balloons provide benefit, following standard care high-pressure balloon angioplasty, in the treatment of arteriovenous fistulas. Hence, in view of the benefit suggested by other trials, the role of paclitaxel-coated angioplasty balloons remains uncertain.

Plain versus paclitaxel-coated balloon angioplasty in arteriovenous fistula and graft stenosis: An umbrella review

An umbrella review was performed to synthesize the evidence from systematic reviews/meta-analyses of clinical trials investigating the efficacy and safety of paclitaxel-coated balloons (PCB) vs. conventional balloon angioplasty in arteriovenous fistulas (AVFs) and grafts stenosis.Medline (via PubMed) and SCOPUS databases were searched up to July 15th 2020. All meta-analyses that enrolled randomized controlled trials (RCTs) comparing PCB with plain balloons in AVFs and grafts were included. Re-analysis of original data was performed assessing predictive intervals (PI). Quality of the included meta-analyses was assessed using AMSTAR score. Eight meta-analyses were included and four clinical outcomes [target lesion primary patency (TLPP), circuit primary patency, mortality, complication rate] derived from 14 RCTs, were analyzed. There were no significant differences in the TLPP in meta-analyses providing data purely from autologous AVFs. Significant benefits regarding TLPP and circuit primary patency at 3, 6, and 12-months in favor of PCB were reported in four meta-analyses mixing AVFs and grafts; however when PI were assessed, in all but one meta-analysis these included the null value, indicating no significant benefit. In only one meta-analysis significant difference of TLPP at 12-months in favor of PCB was noticed. (Odds Ratio 0.0009 PI: 0.28-0.85) No mortality difference was noticed in four meta-analyses providing data up to 24 months. In conclusion this overview revealed a modest benefit of using PCB angioplasty compared to plain angioplasty in AVFs and graft stenosis. No increased mortality was noticed in the PCB group.

Efficacy of ultrasound-guided percutaneous transluminal angioplasty for arteriovenous fistula stenosis or occlusion at juxta-anastomosis: A 3-year follow-up cohort study

OBJECTIVE

Arteriovenous fistula (AVF) is the preferred access for hemodialysis. Percutaneous transluminal angioplasty (PTA) has become a choice for AVF stenosis, and ultrasound has been used in PTA more frequently.

METHODS

This single-center retrospective cohort study analyzed 129 patients who underwent PTA in the First Affiliated Hospital of Chongqing Medical University from January 2016 to December 2016. Angioplasty was performed using a noncompliant high-pressure balloon. The process was visualized by duplex scan. Our inclusion criteria were as follows: (1) stenoses or occlusions were located at the juxta-anastomosis site: the first 5 cm of the vein distal to the anastomosis; (2) stenosis was confirmed with the following conditions: (a) flow rates are <500 mL/min in the brachial artery and <200 mL/min in the fistula during dialysis, and (b) the stenosis diameter is <1.7 mm. We used the Kaplan-Meier curve to show the postintervention primary and secondary patency rates of patients with stenosis and occlusion.

RESULTS

Altogether, 129 patients with 76 males were analyzed. Moreover, 104 have AVFs on the left arm, and only one patient had an ulnar-basilic AVF, whereas others had a radial-cephalic AVF. The postintervention primary patency rates are better in occlusion cases (P < .05), whereas secondary patency rates have no difference. The postintervention primary patency rates are better in patients without diabetes mellitus (P < .05), whereas the secondary patency rates had no difference.

CONCLUSIONS

For juxta-anastomosis site stenosis or occlusion, PTA can be used to obtain satisfactory results.

Early (6 months) results of a pilot prospective study to investigate the efficacy and safety of sirolimus coated balloon angioplasty for dysfunctional arterio-venous fistulas: MAgicTouch Intervention Leap for Dialysis Access (MATILDA) Trial

Background

The aim of this pilot study was to evaluate the safety and efficacy of the MagicTouch™ sirolimus-coated balloon (SCB) catheter (Concept Medical Inc., Tampa, FL, US) on improving the patency of failing arterio-venous fistulas (AVF) with de novo and recurrent stenoses. MATILDA reports early outcomes at 3- and 6 months post intervention.

Methods

Single-centre, single-arm prospective pilot study of 33 (18 males; mean age 64.7±11.6 years) end-stage renal failure Asian patients with a dysfunctional AVF, who underwent SCB angioplasty between May 2019-January 2020. All procedures were performed under local anaesthetic without sedation and as day surgery. All patients were prescribed dual antiplatelet therapy for 3 months and followed up with Duplex ultrasound at 3 and 6 months.

Results

47 stenotic target lesions treated and 24/33 (72.7%) patients were for restenosis. Main indications for intervention was low/dropping access flow (21/33; 63.6%) and most common target lesion was in the juxta-anastomosis (19/47; 40.4%). There was 100% technical and procedural success. There were no peri-procedural complications related to the SCB. The target lesion primary patency rates at 3 and 6 months were 46/47 (97.9%) and 29/35 (82.9%) respectively. Circuit access patency rates at 3 and 6 months were 31/33 (93.9%) and 17/25 (68%) respectively. There was one (2.9%) death at 6 months and 4/33 (12.1%) overall to date, all from patients’ underlying co-morbidities.

Conclusions

SCB angioplasty for dysfunctional AVF circuits is a safe and efficacious modality in Asian haemodialysis patients at six months comparable if not better than the paclitaxel data reported to date in the literature.

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.

Paclitaxel drug-coated balloon angioplasty for the treatment of failing arteriovenous fistulas: a single-center experience

Objectives: To report our experience of angioplasty with Lutonix (Bard Peripheral Vascular, Inc., Tempe, AZ) drug-coated balloon (DCB) for the treatment of failing arteriovenous fistulas (AVF).Materials and methods: Retrospective, single-center analysis consisting of 14 patients treated with Lutonix paclitaxel DCBs in the period from July 2015 through April 2017. We analyzed technical success, clinical success, primary patency of the target lesion, primary patency of the dialysis circuit, and the rate of complications. Regular follow-up of AVF patency was realized by clinical examination and duplex ultrasonography. The Kaplan-Meier survival method was applied to determine the cumulative primary patency of the target lesion and the dialysis circuit.Results: Technical success was 100% and clinical success 92.9%. There were no major or minor complications. Cumulative target lesion primary patency after DCB was 69.2% at 6 months and 31.6% at 12 months. Cumulative vascular circuit primary patency was 61.5% at 6 months and 31.6% at 12 months.Conclusion: Compared to results reported in literature with plain old balloon angioplasty (POBA), Lutonix paclitaxel DCB angioplasty proved a short-term patency benefit in treatment of dialysis AVF stenosis.

Mortality After Paclitaxel-Coated Device Use in Dialysis Access: A Systematic Review and Meta-Analysis

Purpose: To report the risk of all-cause mortality in patients who underwent dialysis access treatment using paclitaxel-coated devices compared with percutaneous transluminal angioplasty (PTA) with an uncoated balloon. Materials and Methods: A systematic review and meta-analysis of randomized controlled trials were performed to investigate the mortality outcomes associated with paclitaxel-coated devices in the treatment of patients with a failing dialysis access (last search date February 28, 2019). The primary endpoint was all-cause mortality. This analysis included 8 studies comparing paclitaxel-coated balloon (PCB) angioplasty (n=327) and PTA (n=331) in the treatment of failing dialysis access. None investigated paclitaxel-coated stents. Mortality data were pooled using a random effects model. Statistical heterogeneity was evaluated with a chi-square test and the I2 statistic. Summary statistics are expressed as relative risk ratios (RR) with a 95% confidence interval (CI). Results: At the pooled mean follow-up of 13.5 months (median 12, range 6–24) all-cause mortality was similar in the PCB group (13.8%) compared with PTA (11.2%; RR 1.26, 95% CI 0.85 to 1.89, p=0.25; I2=0%). Subgroup analysis, stratified according to length of follow-up, confirmed that there were no statistically significant differences in mortality at short- and midterm follow-up [6-month (8 studies): 5.2% vs 4.8%, RR 1.24, 95% CI 0.62 to 2.47, p=0.55; 12-month (6 studies): 6.3% vs 6.0%, RR 1.06, 95% CI 0.43 to 2.63, p=0.90; and 24-month (3 studies): 19.0% vs 13.5%, RR 1.38, 95% CI 0.90 to 2.12, p=0.14). Conclusion: The analysis found no difference in short- to midterm mortality among patients treated with a drug-coated balloon compared with PTA. With proven benefit and no evidence of harm, the authors recommend ongoing use of PCB for the failing dialysis access.

Drug-coated balloon angioplasty in failing haemodialysis arteriovenous shunts: 12-month outcomes in 200 patients from the Aperto Italian registry

Background:

We evaluated the safety and technical and clinical outcomes of angioplasty with a drug-coated balloon for the management of venous stenosis in arteriovenous grafts and arteriovenous fistulas in patients undergoing haemodialysis.

Methods:

Data were obtained from an ongoing prospective, non-randomised registry conducted at three Italian centres. Patients were treated with a drug-coated balloon according to standard procedures in each participating centre. Evaluation was by colour Doppler imaging every 3 months. The primary end-point was primary assisted patency. The secondary end-point was the rate of assisted patency of the vascular access.

Results:

A total of 311 angioplasty procedures in 200 patients, (60.4% male), were analysed. The procedural success rate was 100%. A total of 192 treatments of restenosis were necessary in 81 patients during average 21 ± 8 months follow-up. Kaplan–Meier estimates indicated that 88.0%, 64.2% and 40.6% of treated lesions were free from restenosis at 6, 12 and 24 months, respectively. Including multiple angioplasty, circuit patency rates were 99.2%, 92.5% and 84.8% at 6, 12 and 24 months, respectively. Primary patency rates were highest in shunts treated de novo with drug-coated balloons. Risk of restenosis was associated with circuit age (p = 0.017), history of treatment with conventional angioplasty (p < 0.001) and the kind of balloon used during pre-dilation (p = 0.001).

Conclusion:

The results suggest that favourable long-term patency rates can be achieved with the drug-coated balloon in a varied population of patients with failing haemodialysis arteriovenous shunts treated under conditions of actual care.

Factors affecting arteriovenous fistula dysfunction: A narrative review

Vascular access dysfunction is one of the most important causes of morbidity and mortality in haemodialysis patients, contributing to up to one third of hospitalisations and accounting for a significant amount of the health care costs of these patients. In the past decades, significant scientific advances in understanding mechanisms of arteriovenous fistula maturation and failure have contributed to an increase in the amount of research into techniques for creation and strategies for arteriovenous fistula dysfunction prevention and treatment, in order to improve patient care and outcomes. The aim of this review is to describe the pathogenesis of vascular access failure and provide a comprehensive analysis of the associated risk factors and causes of vascular access failure, in order to interpret possible future therapeutic approaches. Arteriovenous fistula failure is a multifactorial process resulting from the combination of upstream and downstream events with consequent venous neo-intimal hyperplasia and/or inadequate outward remodelling. Inflammation appears to be central in the biology of arteriovenous fistula dysfunction but important triggers still need to be revealed. Given the significant association of arteriovenous fistula failure and patient's prognosis, it is therefore imperative to further research in this area in order to improve prevention, surveillance and treatment, and ultimately patient care and outcomes.

Factors associated with outcome after successful radiological intervention in arteriovenous fistulas: A retrospective cohort

Introduction:

Arteriovenous fistulas are the best form of vascular access for haemodialysis. A radiological balloon angioplasty is the standard treatment for a clinically relevant stenosis, but the recurrence rate is high. Data on factors associated with recurrence are limited.

Methods:

A single centre, retrospective analysis was performed for 124 consecutive patients who had successful interventions for dysfunctional arteriovenous fistulae, to examine factors associated with post-intervention patency. Follow-up was at least 1 year for all patients. Variables associated with primary and cumulative patency were pre-specified and assessed using both un-adjusted (univariate) and adjusted Cox proportional hazards models. Analysis was repeated for a subgroup of 80 patients with a single lesion only in order to examine the potential effects of stenotic lesion characteristics on patency.

Results:

Factors found to have a significant association with poorer outcomes (less time to loss of patency) included thrombosis at the time of intervention and a history of previous intervention. Fistula age (log days) was significantly associated with better outcomes (greater time to loss of patency). Non-white ethnicity, lesion length, and patient age were also significantly associated with accelerated loss of patency.

Discussion:

The factors we have identified as linked to poor outcome may help to identify patients in whom a balloon angioplasty is unlikely to provide a durable outcome. This may prompt exploring alternative treatment or dialysis options at an early stage.

Disruptive technological advances in vascular access for dialysis: an overview

End-stage kidney disease (ESKD), one of the most prevalent diseases in the world and with increasing incidence, is associated with significant morbidity and mortality. Current available modes of renal replacement therapy (RRT) include dialysis and renal transplantation. Though renal transplantation is the preferred and ideal mode of RRT, this modality may not be available to all patients with ESKD. Moreover, renal transplant recipients are constantly at risk of complications associated with immunosuppression and immunosuppressant use, and posttransplant lymphoproliferative disorder. Dialysis may be the only available modality in certain patients. However, dialysis has its limitations, which include issues associated with lack of vascular access, risks of infections and vascular thrombosis, decreased quality of life, and absence of biosynthetic functions of the kidney. In particular, the creation and maintenance of hemodialysis vascular access in children poses a unique set of challenges to the pediatric nephrologist owing to the smaller vessel diameters and vascular hyperreactivity compared with adult patients. Vascular access issues continue to be one of the major limiting factors prohibiting the delivery of adequate dialysis in ESKD patients and is the Achilles' heel of hemodialysis. This review aims to provide a critical overview of disruptive technological advances and innovations for vascular access. Novel strategies in preventing neointimal hyperplasia, novel bioengineered products, grafts and devices for vascular access will be discussed. The potential impact of these solutions on improving the morbidity encountered by dialysis patients will also be examined.

Drug-eluting balloon: design, technology and clinical aspects

A drug-eluting balloon is a non-stent technology in which the effective homogenous delivery of anti-proliferative drugs is processed by the vessel wall through an inflated balloon. This is done to restore luminal vascularity in order to treat atherosclerosis, in-stent restenosis and reduce the risk of late thrombosis without implanting a permanent foreign object. The balloon technology relies on the concept of targeted drug delivery, which helps in the rapid healing of the vessel wall and prevents the proliferation of smooth muscle cells. Several drug eluting devices in the form of coated balloons are currently in clinical use, namely DIOR^®, PACCOCATH^®, SeQuent^®Please and IN.PACT™. The device varies in terms of the material used for making the balloon, the coating techniques, the choice of coated drug and the release pattern of the drug at the site. This review gives an insight into the evolution, rationale and comparison of the marketed drug-eluting balloons. Here, different coating techniques have been analysed for the application and critical analysis of available DEB technologies, and a technical comparison has been done.

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.

A Single-Center Retrospective Analysis of the Efficacy of a New Balloon Catheter in Autogenous Arteriovenous Fistula Dysfunction Resistant to Conventional Balloon Angioplasty

PURPOSE

The purpose of the study was to present a new alternative balloon catheter option for autogenous arteriovenous fistula (AVF) dysfunction with a stiff constriction resistant to conventional balloon angioplasty.

METHODS

Our first series of 51 patients with autogenous AVF dysfunction who were simultaneously treated with VascuTrak™ balloon catheter, following failed conventional balloon therapy (failure was defined as residual stenosis of >30%), were retrospectively observed and analyzed. The indices that were used to evaluate the clinical efficacy of VascuTrak balloon catheter included the immediate technical success rate, residual stenosis, successful dilation times, degree of pain assessed using the Visual Analog Scale, complications, and follow-up patency rate.

RESULTS

The stenotic or occlusive lesions of all 51 cases resistant to conventional balloon angioplasty were promptly eliminated or alleviated (residual stenosis rate ≤ 30%), with a 100% immediate technical success rate. VascuTrak balloon catheters were successful in achieving full dilation under working pressure, of which 44 cases required a 1-time dilation (86.3%) and 7 cases required 2 dilations, which differed significantly from the average of 2.4 dilations required by the preceding conventional balloon therapy (P < 0.0001). A statistically significant improvement in the degree of pain experienced by patients who received VascuTrak balloon dilation was observed compared to that of the preceding conventional balloon dilation (P < 0.0001). One case of a brachial artery pseudoaneurysm complication occurred in the perioperative period. The primary patency rate was 88.2% at 6 months and 74.5% at 12 months.

CONCLUSION

The use of VascuTrak balloon catheter to treat autogenous AVF dysfunction resistant to conventional balloon angioplasty appears to be safe and effective, although further, large randomized controlled trials are necessary.

Drug eluting balloons for resistant arteriovenous dialysis access stenosis

Vascular access maintenance is vital for hemodialysis patients. Conventional balloon angioplasty is the gold standard of treatment in endovascular therapy according to published guidelines, accompanied by bare metal stents as a bail-out method. Several devices have been used so far with a view to improve patency outcomes, but only covered stents have been proposed as a valid alternative and only for venous juxta-anastomotic stenosis of arteriovenous grafts. Paclitaxel-coated balloons (PCBs) have been extensively investigated in the last few years in pilot studies with small numbers of patients in dialysis access. Results from these studies have been promising so far; however, a larger number of subjects is needed to prove outcomes. Aim of this analysis is to discuss current available studies and explore some critical aspects of PCB use in dialysis access treatment.

Paclitaxel-Coated Balloons for the Treatment of Dysfunctional Dialysis Access. Results from a Single-Center, Retrospective Analysis

PURPOSE

To investigate the safety and effectiveness of lutonix paclitaxel-coated balloon (PCB) for the treatment of dysfunctional dialysis access.

MATERIALS AND METHODS

This was a single-center, single-arm, retrospective analysis of 39 patients (23 male, 59 %) undergoing 61 interventions using 69 PCBs in a 20-month period. There was a balance between arteriovenous fistulae (AVF) and grafts (AVG) (20 AVFs, 19AVGs), and the majority of lesions were restenotic (25/39, 64.1 %). Mean balloon diameter used was 6.6 mm and length 73.4 mm. Primary outcome measure was target lesion primary patency (TLPP) at 6 months, while secondary outcome measures included factors affecting TLPP and major complications. As there were lesions treated more than once with PCB, authors also compared patency results after first and second PCB angioplasty.

RESULTS

TLPP was 72.2 % at 6 months with a median patency of 260 days according to the Kaplan-Meier survival analysis. No major complications occurred. TLPP between AVFs and AVGs (311 vs. 237 days, respectively; p = 0.29) and de novo and restenotic lesions was similar (270.5 vs. 267.5 days, respectively; p = 0.50). In 14 cases, in which lesions were treated with two PCB angioplasties, a statistically significant difference in TLPP after the second treatment was noted (first intervention 179.5 days vs. second intervention 273.5 days; p = 0.032).

CONCLUSION

In this retrospective analysis, Lutonix PCB proved to be safe and effective in treating restenosis in dysfunctional dialysis access with results comparable to the literature available. Larger studies are needed to prove abovementioned results.

Cutting balloons, covered stents and paclitaxel-coated balloons for the treatment of dysfunctional dialysis access

Percutaneous transcatheter balloon angioplasty has evolved to the current mainstay treatment for salvage of dysfunctional dialysis access. Nonetheless, it is frequently associated with recurrent vessel restenosis and the need for multiple repeat treatments in order to maintain hemodynamic patency. Cutting-balloons, covered stents or stent-grafts, and paclitaxel-coated balloons have been extensively tested and investigated with the aim to improve immediate anatomical and long-term clinical results. Areas covered: In the present overview, we discuss the background and appraise relevant medical literature on the aforementioned technologies and provide a more in-depth synthesis of the results of different clinical studies for each device category. We will also discuss the limitations in the mode of action of each group of devices and envision what the future holds for the challenging field of dialysis access interventions. Expert commentary: We propose a good practice algorithm for the treatment of thrombosed or dysfunctional dialysis access.

Arteriovenous Access Failure, Stenosis, and Thrombosis

Vascular access–related complications can lead to patient morbidity and reduced patient quality of life. Some of the common arteriovenous access complications include failure to mature, stenosis formation, and thrombosis.

Drug-coated balloon angioplasty for dialysis access fistula stenosis

Maintaining vascular access patency represents a tremendous challenge in hemodialysis patients. Although "native" arteriovenous fistula (AVF) is currently recommended as primary vascular access, neointimal hyperplasia stenoses frequently develop, with a risk for AVF thrombosis and vascular access loss. For years, first-line treatment of AVFs stenoses has been percutaneous transluminal angioplasty, generally with high-pressure or cutting uncoated balloons. However, restenosis and reintervention rates remain incredibly high and occur, according to recent studies, in up to 60% and 70% of patients at 6 and 12 months, respectively. Drug-coated balloons delivering paclitaxel at the angioplasty site have proved their superiority in the treatment of coronary and peripheral arterial stenoses. Paclitaxel reduces neointimal hyperplasia and drug-coated balloons, therefore, it represents an attractive option for AVF stenoses. Because data are scarce, the aim of this paper was to review the concepts and current results of drug-coated balloons in AVF stenosis management.