Prospective, randomized study of cutting balloon angioplasty versus conventional balloon angioplasty for the treatment of hemodialysis access stenoses

Endovascular tools for vascular access stenosis: Flow-chart proposal

Stenosis represents the most relevant arteriovenous fistula (AVF) pathology and can affects the entire conduit forming the fistula, from afferent artery to central venous vessels. Correction of vascular access stenosis significantly affects the survival and quality of life for end stage renal disease patients (ESRD) dependent on hemodialysis. Guidelines consider the procedure of percutaneous transluminal angioplasty (PTA) relevant for the primary treatment of these lesions with excellent results in restoring AVF immediately at the end of the procedure. From first AVF angioplasty in 1981 to now, wide scientific innovation has led to development of new devices, composed by different materials and technologies, specific for the site and the type of stenosis to be treated, able to manage resistant stenotic lesion and to reduce stenosis recurrences. International guidelines do not clearly specify all treatment possibilities in the individual case. In this review the authors want to provide specific information on most used devices for stenosis treatment based on literature evidence, showing when and where to use the various tools available with flow-chart treatment proposal.

Treatment of intragraft stenosis in hemodialysis grafts with Supera stents: A retrospective study

PURPOSE

To report the patency rates after implantation of an interwoven nitinol stent to salvage failing arteriovenous grafts (AVGs) caused by intragraft stenoses.

METHODS

Between May 2018 and May 2020, 21 Supera stents were placed in 20 patients (18 women; mean age: 79.9 years) who had a failing AVG due to repeat intragraft stenoses. Recurrent AVG dysfunction with same intragraft stenosis within 3 months after first time angioplasty was a criterion for stenting. Those with concurrent treatment for other lesions were excluded.

RESULTS

The technical success rate was 100%. Intragraft stenoses were treated at a median of 19.7 (interquartile range: 6-36) months after graft creation. Access circuit primary patency rates after stent placement were 84% and 35% at 6 and 12 months, respectively. Access circuit secondary patency rates were 100% at 6 and 12 months and 89% at 18 months. Only one patient presented with graft failure due to proximal drainage vein occlusion. The target lesion patency rates were 100% at 6 months and 75% at 12 months. The rate of reintervention for intragraft lesion was 0.15 procedures per year. Stent distortion did not occur under regular cannulation.

CONCLUSION

The interwoven nitinol stent is a promising treatment for failing AVGs with recurrent intragraft stenoses. The 1-year access circuit primary, secondary, and target lesion patency rates were acceptable, with a low reintervention rate. Stent fracture does not occur in areas of needle puncture.

Contemporary review of management techniques for cephalic arch stenosis in hemodialysis

The type of hemodialysis access and its preservation impact the quality of life and survival of patients undergoing hemodialysis. Vascular access complications are among the top causes of morbidity, hospitalization, and catheter use, with significant economic burden. Poor maturation and stenosis continue to be key impediments to upper arm arteriovenous fistula feasibility. Cephalic arch is a common location for vascular access dysfunction due to its distinctive anatomy, complex valves, and biochemical alterations attributable to renal failure. Understanding cephalic arch stenosis is critical due to its high prevalence and treatment failure. The appropriate management option is highly debatable and mostly dependent on patient characteristics and interventionist's preference. Current options include, percutaneous transluminal balloon angioplasty, stent grafts, bare metal stents, cutting balloon angioplasty, endovascular banding, and surgical procedures. This article discusses the etiologies of cephalic arch stenosis as well as currents trends in management including endovascular and surgical options.

Dual outflow upper arm arteriovenous fistula: An effective technique to prevent cephalic arch stenosis

Cephalic arch stenosis (CAS) is critical point to maintain functional arteriovenous fistula (AVF) in patients undergoing hemodialysis with brachio-cephalic AVFs. In this study, we aimed to determine the effectiveness of dual outflow (cephalic and basilic veins) as a surgical method to prevent CAS. Between July 2016 and December 2019, 369 patients underwent upper arm AVF creation. Among them the 251 patients were enrolled in this retrospective study. Two hundred seven underwent brachio-cephalic arteriovenous fistula (BCAVF) and 44 underwent brachio-cephalicbasilic arteriovenous fistula (BCBAVF). From the 251 patients, diabetes mellitus (66.7% vs 36.4%, P < .001) and hypertension (91.3% vs 75%, P = .002) were more common in the patient group who underwent BCAVF surgery; however, the difference in volume flow to the fistula did not differ between the 2 groups. CAS (30.4% vs 9.1%, P = .004) and fistula occlusion (15.9% vs 4.5%, P = .048) were likely to occur in the BCAVF group. The primary patency rates at 12 months were 74.3% and 86.4% for the BCAVFs and BCBAVFs, respectively (P = .075). The primary-assisted patency rates at 12 months were 87.0% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .145). Secondary patency rates at 12 months were 92.2% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .023). Compared to BCAVF, traditional upper arm AVF, upper arm AVF with cephalic and basilic vein dual drainage can be optimal surgical method to preventing CAS.

Comparison of peripheral cutting balloon angioplasty with conventional balloon angioplasty for recurrent hemodialysis vascular access stenosis: A prospective randomized controlled trial

PURPOSE

This study aimed to compare the efficacy and safety of cutting balloon angioplasty (CBA) and conventional balloon angioplasty (control group) for recurrent vascular access stenosis in arteriovenous fistulas.

MATERIALS AND METHODS

This prospective, randomized single-center clinical trial included patients with hemodynamically significant recurrent vascular access stenosis of an arteriovenous fistula. The Kaplan-Meier method was used to assess primary patency, whereas the log-rank test was used to evaluate differences in patency between groups. Functional evaluations were performed using Doppler ultrasonography.

RESULTS

Patients (n = 122) were randomly assigned to undergo CBA or conventional balloon angioplasty between December 2012 and November 2017. The clinical success rate was 100% in both groups. The anatomical success rates were 65% and 56% in the CBA and control groups, respectively. The primary patency of the target lesion was significantly better in the CBA group (33.3%) than in the control group (16.1%) at 6 months (hazard ratio, 0.50; 95% confidence interval, 0.33-0.77; p = 0.00171). The stenosis percentage decreased significantly after angioplasty in the CBA group (Δ-50.7%) compared with the control group (Δ-41.9%) (p = 0.0008). Access flow, measured using duplex Doppler ultrasonography, improved after angioplasty in both groups (300-526 ml/min in the control group and, 268-546 ml/min in the CBA group). Change in access flow (Δ + 278 ± 162) in the CBA group tended to be greater than that in the control group (Δ + 226 ± 151) (p = 0.07). However, the difference was not statistically significant.

CONCLUSION

In patients with recurrent vascular access stenosis of the arteriovenous fistula CBA is effective and superior to conventional angioplasty.

ACR Appropriateness Criteria® Dialysis Fistula Malfunction

The creation and maintenance of a dialysis access is vital for the reduction of morbidity, mortality, and cost of treatment for end stage renal disease patients. One's longevity on dialysis is directly dependent upon the quality of dialysis. This quality hinges on the integrity and reliability of the access to the patient's vascular system. All methods of dialysis access will eventually result in dialysis dysfunction and failure. Arteriovenous access dysfunction includes 3 distinct classes of events, namely thrombotic flow-related complications or dysfunction, nonthrombotic flow-related complications or dysfunction, and infectious complications. The restoration of any form of arteriovenous access dysfunction may be supported by diagnostic imaging, clinical consultation, percutaneous interventional procedures, surgical management, or a combination of these methods. This document provides a rigorous evaluation of how variants of each form of dysfunction may be appraised and approached systematically. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Relationship Between Intimal Thickness on Ultrasonography and Long-Term Patency of Arteriovenous Fistula Restenosis After Cutting Balloon Versus High Pressure Balloon Angioplasty

BACKGROUND

To investigate the relationship between intimal thickness on ultrasonography and long-term patency of arteriovenous fistula restenosis after cutting balloon and high pressure balloon angioplasty.

METHODS

We retrospectively compared the outcomes between cutting balloon angioplasty and high pressure balloon angioplasty in 149 patients with hemodialysis access restenosis. The relationship of intimal thickness and primary assisted patency of hemodialysis access on ultrasonography was investigated as the primary outcome, using Kaplan-Meier survival analysis and Cox proportional hazards model. The second outcomes included residual diameter, blood flow, and venous pressure of hemodialysis access before and after angiography and balloon diameter and inflation pressure.

RESULTS

Primary assisted patency in cutting balloon angioplasty was 90.6%, which was significantly (P = 0.001) more than that of 37.9% in high pressure balloon angioplasty during the 20-month follow-up period. Cox proportional hazards model screened significant factors including procedure type (high pressure or cutting, P = 0.004), inflation pressure (P = 0.013), preoperative intimal thickness (P = 0.009), and difference of intimal thickness (P = 0.029). Finally, procedure type (P = 0.012) and preoperative intimal thickness (P = 0.033) were identified for predicting primary assisted patency by multivariate Cox proportional hazards model.

CONCLUSIONS

Compared to high pressure balloon angioplasty for treating patients with hemodialysis access restenosis, cutting balloon angioplasty had a better primary assisted patency. The increase of intimal thickness on ultrasonography after angiography was inversely correlated with primary assisted patency.

Central vein stenosis: a rare cause of orbital congestion in a haemodialysis patient

We report a rare, potentially sight-threatening ocular complication due to central venous stenosis related to a previous site of haemodialysis catheter. A dialysis-dependent woman in her 60s presented with left eye redness for 1 month followed by a remarkably prominent vessel on the left upper eyelid for 2 weeks. Examinations found left eyelid oedema with prominent venous dilatation on the upper eyelid as well as left eye mild proptosis, conjunctiva injection with corkscrew vessels, raised intraocular pressure, and dilated and tortuous retina vessels. Central thoracic venogram showed total occlusion on the left brachiocephalic vein with retrograde reflux to the jugular vein. An endovascular percutaneous transluminal balloon angioplasty was performed for the left brachiocephalic vein stenosis, which resolved the orbital, facial and neck venous congestion. The patient remained asymptomatic after 1 year.

Combined treatment of dysfunctional dialysis access with cutting balloon and paclitaxel-coated balloon in real world

Background: Dysfunction in arteriovenous (AV) access is a common reason for subsequent intervention. To evaluate the results of endovascular treatment of AV access lesions using cutting balloon (CB) and drug-coated balloon (DCB) angioplasty compared to standard treatment using plain-old balloon angioplasty (POBA). Patients and methods: Patients who retrospectively were selected from a prospectively maintained database. Primary endpoint was primary patency rate at the target lesion up to 12 months after index procedure. Secondary endpoints were the acute treatment success, the "bail out" stent rate, primary patency at 6 months, freedom from target lesion revascularization (TLR), AV access replacement and surgical revision during a follow-up period up to 12 months, and all-cause mortality rate stratified to patients treated with and without DCB. Results: One hundred and eighty-four patients met the inclusion criteria. POBA as stand alone or combined with DCB angioplasty was performed in 71 patients (38.6%), CB in 54 patients (29.3%), and in 59 patients (32.1%), both CB and DCB were used. Primary patency rate at 12 months was 31.6% for the POBA/DCB-group, 52.3% for the CB-group, and 64.8% for the CB/DCB-group, respectively. In total, 80 patients (51.6%) had a TLR including endovascular or surgical revision, or a shunt replacement. All-cause mortality at 12 months was 7.2% in the DCB group and 9.1% in the group of patients treated without a DCB (p=0.747). Conclusions: The use of CB seems to be crucial for a better outcome. The combination of CB and DCB achieves the best patency results at mid-term.

Stent Diameter, Not Cephalic Arch Anatomy, Predicts Stent Graft Patency in Cephalic Arch Stenosis

PURPOSE

To investigate the relationship between anatomic factors and primary patency of brachiocephalic arteriovenous fistulae (AVFs) after stent graft (SG) placement for cephalic arch stenosis (CAS).

MATERIALS AND METHODS

This retrospective study reviewed all cephalic arch SGs placed in brachiocephalic AVFs in a tertiary academic medical center between 2014 and 2017. Sixty-three patients were included in the study. The mean patient age at the time of SG placement was 62.6 years ± 19, and the mean patient follow-up was 1,994 days ± 353. A cohort of patients (n = 31) who underwent brachiocephalic fistulograms for CAS but only received percutaneous transluminal angioplasty (PTA) was the control group. Patient demographic characteristics, AVF anatomy, SG type, and clinical outcomes were reviewed. The duration of primary cephalic arch patency after SG placement was compared with that after previous PTA.

RESULTS

The median AVF age at the time of data retrieval was 345 days. The primary patency of CAS after SG placement at 6 months, 12 months, and 3 years was 64%, 49.9%, and 23.5%, respectively. Primary cephalic arch patency was significantly associated with the SG diameter (P = .007) but not with cephalic vein-axillary vein junction anatomy, size of feeding artery, or SG length (P > .05). The primary patency of CAS in patients treated with PTA only (n = 31) at 6 months, 12 months, and 3 years was 61%, 35%, and 0%, respectively, which was significantly lower than that in patients treated with SG placement (P = .01).

CONCLUSIONS

This study showed that the primary patency of CAS after SG placement was significantly higher than that of PTA-only treatment. Moreover, primary cephalic arch patency after SG placement was significantly associated with the SG diameter.

Drug-eluting balloon (DEB) versus plain old balloon angioplasty (POBA) in the treatment of failing dialysis access: A prospective randomized trial

Objective

To compare the efficacy of angioplasty using drug-eluting balloons (DEB) compared with plain old balloon angioplasty (POBA) to reduce the rate of restenosis.

Methods

This prospective, single-centre, single-blinded, 1:1 randomized, clinical trial enrolled patients that had primary or restenotic lesions in native upper extremity arteriovenous (AV) fistulas or at the graft-venous anastomosis. Patients were randomized to angioplasty with a POBA or a DEB. The primary effectiveness endpoints were freedom from target lesion revascularization (TLR) and functional status of access circuit at 12 months.

Results

A total of 42 (28 male, 14 female; age range, 42–83 years) patients were enrolled. Patients were followed for 12 months. No significant differences were detected between the POBA and DEB groups regarding total number of TLR procedures (31 versus 36, respectively), freedom from TLR (3 versus 4, respectively) and functional status of the access circuit at 12 months (14 of 20 patients [70%] versus 17 of 22 patients [77%], respectively).

Conclusion

This clinical trial did not demonstrate any significant differences between DEB angioplasty and standard balloon angioplasty when treating dysfunctional haemodialysis access.

Unilateral jugular vein stenosis in five horses and experience with percutaneous transluminal angioplasty

BACKGROUND

Venous stenosis, a possible cause of jugular dilatation and congestion, is well known in human medicine but has poorly been described in horses.

OBJECTIVE

To report unilateral jugular vein stenosis as a cause of jugular vein dilatation in horses and describe treatment by percutaneous transluminal angioplasty (PTA).

STUDY DESIGN

Case report.

METHODS

Details of horses diagnosed with unilateral jugular stenosis were retrieved from medical records.

RESULTS

Five horses were presented with a non-painful, unilateral dilatation of the jugular vein of which two horses showed headshaking during exercise. In one horse an indwelling catheter had been used and jugular dilatation developed 4 weeks later. In the other horses, no intravenous injections had been administered in the months before jugular dilatation developed. Ultrasonographic examination revealed venous stenosis in all horses approximately 5-10 cm cranial to the thoracic inlet. The internal diameter at the level of this stenosis was only 1-3.1 mm. The length of the stenosis was about 15-19 mm with a markedly thickened intima and media on ultrasonography. After enoxaparin treatment, PTA was performed in three horses. During the procedure the stenotic vein was dilated three times with progressively increasing pressures up to 12 atm. The stenotic diameter increased to a maximum of 4.9 mm with improved jugular blood flow. Aftercare included anti-inflammatory and anti-thrombotic therapy.

CONCLUSION

Jugular vein stenosis occurs in horses and should be included in the differential diagnoses of unilateral jugular vein dilatation. It may present in the absence of previous intravenous treatment. PTA of the jugular vein is feasible to improve jugular blood flow.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Network meta-analysis of trials comparing first line endovascular treatments for arteriovenous fistula stenosis

OBJECTIVE

We investigated the comparative effectiveness of different endovascular treatments for patients with failing autogenous arteriovenous fistulas (AVFs) with outflow vein stenosis.

METHODS

The Medline (via PubMed) and SCOPUS databases were searched. We performed a systematic review and network meta-analysis of randomized controlled trials that had investigated the effectiveness of plain balloon angioplasty (PBA), cutting balloon angioplasty, and drug-coated balloon angioplasty (DCBA) to treat vein stenoses in autogenous AVFs. Studies of central vein stenosis were excluded. The main outcome measures were the failure rates at 6 months and 1 year after treatment.

RESULTS

Eleven randomized controlled trials were included, with 814 patients, 395 of whom had undergone PBA. The network meta-analysis showed that DCBA at 6 months was significantly more effective than PBA (odds ratio, 0.39; 95% confidence interval, 0.18-0.81) and ranked as the best treatment option, although the difference was not statistically significant compared with cutting balloon angioplasty (odds ratio, 0.65; 95% confidence interval, 0.20-2.12). The differences among the three treatments at 1 year were not statistically significant. Additional conventional pairwise meta-analyses did not find significant differences at 1 year.

CONCLUSIONS

In failing AVFs with outflow stenosis, DCBA was significantly superior to PBA, with improved 6-month failure rates. However the effectiveness of DCBA in the long term deserves further investigation.

Single-Center Prospective Pilot Study of Sirolimus Drug-Coated Balloon Angioplasty in Maintaining the Patency of Thrombosed Arteriovenous Graft

PURPOSE

To investigate the use of a sirolimus drug-coated balloon (DCB) in the management of a thrombosed arteriovenous graft (AVG).

MATERIALS AND METHODS

A single-center prospective pilot study was conducted between October 2018 and October 2019. Twenty patients (age = 67.0 years ± 10; male = 35%; mean time on dialysis = 31 months) with thrombosed upper limb AVG were enrolled. After successful pharmacomechanical thrombectomy and adequate treatment of the graft vein junction, sirolimus DCB angioplasty was performed at the graft vein junction. The patients were followed-up for 6 months, and all adverse events occurring during the study period were recorded.

RESULTS

The primary circuit patency rates at 3 and 6 months were 76% and 65%, respectively, while the assisted-primary circuit patency rates at 3 and 6 months were 82% and 65%, respectively. The 3- and 6-month secondary circuit patency rates were 88% and 76%, respectively. Using Kaplan-Meier analyses, the estimated mean primary, assisted-primary, and secondary patencies were 285 days (95% confidence interval (CI) = 194-376 days), 319 days (95% CI = 221-416 days), and 409 days (95% CI = 333-485 days). No adverse event directly related to sirolimus DCB use was observed.

CONCLUSIONS

The results of this pilot study suggest that the application of sirolimus DCB at the graft vein junction after the successful thrombectomy of AVG may be a feasible option to improve patency outcomes.

Restoring arteriovenous access: Pilot study using a scoring balloon in 50 patients

Background:

Arteriovenous access failure is most often due to the development of neointimal hyperplastic stenoses. Balloon angioplasty remains standard of care for endovascular treatment of stenoses obstructing blood flow in hemodialysis fistulas and grafts. Scoring balloon technologies have been developed to disrupt the atheromatous plaque and have shown to be safe and effective for treating stenosis in the hemodialysis access circuit. However, improvement in patency has yet to be established.

Methods:

This prospective, single-arm study included 50 patients with stenosed hemodialysis fistula/grafts treated with the AngioSculpt® scoring balloon (Philips) and followed for 6 months. The primary endpoint was target lesion primary patency at 2 and 6 months defined as freedom from re-intervention.

Results:

Treatment with the scoring balloon resulted in a reduction in stenosis from 78% ± 13.36% to 7.2% ± 7.57% (mean ± standard deviation). Scoring balloon inflation pressures averaged 11.4 atm; no slippage/dissections occurred. After 2 months, 10% of patients required re-intervention. At 6 months, 19% of patients required re-intervention. The 6-month freedom from re-intervention rate was higher for patients with stenosed fistulas (83.3%) compared to patients with stenosed grafts (71.4%). Six-month patency rates were highest for patients with no or one previous intervention (91.6% and 90.0%, respectively); patients with two to five preceding interventions had a 6-month patency rate of 80%, and those with more than five previous interventions had a 50% 6-month patency rate.

Conclusion:

Results from this pilot study suggest that the AngioSculpt scoring balloon may be a viable treatment option for stenosed arteriovenous fistula/graft access.

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.

Predictors of primary patency after percutaneous balloon angioplasty for stenosis of Brescia-Cimino hemodialysis arteriovenous fistula

OBJECTIVE

Percutaneous transluminal balloon angioplasty (PTA) is recommended as the first choice to treat stenosis of Brescia-Cimino arteriovenous fistulas (B-C AVFs). The ability to predict which B-C AVFs are at risk for recurrent stenosis post-PTA would allow closer monitoring of patients, and possibly result in surgical intervention rather than repeat PTA. The purpose of this study was to identify predictive factors of primary patency after PTA in B-C AVFs.

METHODS

Patients diagnosed with B-C AVF primary stenosis and treated by PTA between November 2013 and March 2018 were included in the study. Patient and stenotic lesion characteristics and PTA procedure factors were included in the analysis. The Kaplan-Meier method was used to analyze the primary patency rate. Cox proportional hazard regression analysis was used to identify factors predictive of decreased primary patency.

RESULTS

74 patients (35 males, 39 females) with a mean age of 61.68 ± 11.44 years (range, 36-84 years) were included in the study. The mean B-C AVF age was 16.34 ± 12.93 months (range, 2-84 months), and the median primary patency time was 7.79 ± 0.48 months. Cox proportional hazard regression analysis revealed stenosis location at the inflow artery [hazard ratio (HR)=3.83, 95% confidence interval (CI): 1.46-10.09] or anastomosis (HR = 1.90, 95% CI: 1.09-3.32), dilation >2 times during PTA (HR = 2.30, 95% CI: 1.22-4.34), and residual stenosis >30% (HR = 2.42, 95% CI: 1.26-4.63) were significantly associated with decreased patency.

CONCLUSION

In conclusion, the primary patency rate of PTA for B-C AVF dysfunction is reduced by dilation >2 times, residual stenosis >30%, and stenosis located at the inflow artery or anastomosis. These results may help in tailoring surveillance programs, multiple PTA, or a proximal re-anastomosis surgery in patients with AVF dysfunction.

ADVANCES IN KNOWLEDGE

A number of studies have been conducted to examine the predictors of primary patency after PTA, however, no definitive conclusions have been reached. Our study revealed that stenosis location at the inflow artery or anastomosis, dilation >2 times during PTA, and residual stenosis >30% were the predictors of primary patency after PTA, which may help in tailoring surveillance programs, multiple PTA, or a proximal re-anastomosis surgery in patients with arteriovenous fistulas dysfunction.

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.

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.

Comparing the 12-month patency of low- versus high-pressure dilation in failing arteriovenous fistulae: A prospective multicenter trial (YOROI study)

PURPOSE

This study was performed to investigate the effect of the balloon dilation pressure on the 12-month patency rate in patients with failed arteriovenous fistulas undergoing hemodialysis.

MATERIALS AND METHODS

In this multicenter, prospective, randomized trial, the 4-mm-diameter YOROI balloon was used for dilation of stenotic lesions. The balloons were inflated to a pressure of 8 atm (low-pressure group) or 30 atm to achieve complete expansion (high-pressure group). The 12-month patency rate after balloon angioplasty was analyzed by the Kaplan-Meier method and log-rank test and/or a Cox proportional hazard model. We also investigated the dilation pressure required to achieve complete expansion in the high-pressure group.

RESULTS

In total, 71 patients were enrolled and allocated to either the low-pressure group (n = 34) or the high-pressure group (n = 37). The 12-month patency rates showed no significant difference between the low- and high-pressure groups (47% and 49%, respectively; p = 0.87). In the low-pressure group, the patency rate was not different between patients with complete dilation and residual stenosis (44% and 50%, respectively; p = 0.87). The Cox proportional hazard model revealed that the 12-month patency rate was associated with the stenosis diameter (hazard ratio 0.36; p = 0.001) and the presence of diabetes (hazard ratio 0.33; p = 0.018). Finally, the pressure required to achieve complete dilation was ≤20 atm in 76% of patients and ≤30 atm in 97% of patients. One patient required a dilation pressure of >30 atm.

CONCLUSION

The patency rate does not differ between low-pressure dilation and high-pressure dilation.

Stenoses in the surgically manipulated segment have better angioplasty response compared to the surgically naive segment in fistulas

Purpose

Balloon angioplasty is the standard treatment for dysfunctional hemodialysis fistulas, but angioplasty response of stenotic lesions located in different segments of the dialysis circuit has not been explicitly evaluated. The purpose of this study is to describe the distribution of stenotic lesions in the most common types of arteriovenous fistulas and to investigate the response to balloon angioplasty of stenotic lesions located in various segments of the fistula circuit.

Materials and Methods

This single-center, retrospective study was approved by the Institutional Review Board. A total of 263 fistulograms performed between January, 2014 and June, 2015 were reviewed. Stenotic lesion response to angioplasty was analyzed based on lesion location using a Kaplan-Meier analysis.

Results

Juxta-anastomotic stenoses (48%) were the most common lesions in radiocephalic fistulas, while the cephalic arch (30%) and venous outflow tract (24%) were the most common locations of stenotic lesions in brachiocephalic fistulas and basilic vein transposition fistulas, respectively. Primary patency after balloon angioplasty was significantly higher in lesions located in the venous segments manipulated during surgeries compared to the lesions located in the surgically naive zone (p = 0.001). The 6-month and 12-month primary patency of lesions post-angioplasty in the surgical zone were 76% and 71% compared to 58% and 43% in the surgically naive segments.

Conclusions

The distribution of stenotic lesions differs among each type of fistula. The primary patency of balloon angioplasty of stenotic lesions located in the surgically manipulated venous segment was significantly better than lesions located in the rest of the fistula circuit.

Monocyte Chemoattractant Protein-1 Levels and Postangioplasty Restenosis of Arteriovenous Fistulas

BACKGROUND AND OBJECTIVES

Inflammation is relevant in restenosis of atherosclerotic vascular diseases, but its role in dialysis arteriovenous fistula remains unknown. In animal studies, upregulation of monocyte chemoattractant protein-1 has been shown in venous segments of arteriovenous fistula. We, therefore, aimed to investigate serial changes in circulating monocyte chemoattractant protein-1 after percutaneous transluminal angioplasty of dialysis arteriovenous fistulas and its relation to restenosis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Fifty-nine patients with dysfunctional arteriovenous fistulas that were referred for percutaneous transluminal angioplasty were enrolled prospectively between January of 2010 and July of 2012. Three of them were excluded due to percutaneous transluminal angioplasty failure or acute infection. Blood was sampled from arteriovenous fistulas at baseline, 2 days, 2 weeks, and 3 months after percutaneous transluminal angioplasty. Clinical follow-up was continued monthly for 3 months. Angiographic follow-up was arranged at the end of 3 months. Seventeen patients without significant stenosis were enrolled as the control group.

RESULTS

Fifty-six patients completed clinical follow-up. Significant increases in monocyte chemoattractant protein-1 were observed at 2 days and 2 weeks (both P<0.001) after percutaneous transluminal angioplasty. Twenty-three (41%) patients had symptomatic restenosis. The restenosis group had a higher percentage change in monocyte chemoattractant protein-1 levels at 2 days (median =47%; interquartile range, 27%-65% versus median =17%; interquartile range, 10%-25%; P<0.001) after percutaneous transluminal angioplasty compared with the patent group. Fifty-two patients completed angiographic follow-up. A positive correlation between relative luminal loss and monocyte chemoattractant protein-1 increase at 2 days after percutaneous transluminal angioplasty was found (r=0.53; P<0.001). In multivariate analysis, postangioplasty monocyte chemoattractant protein-1 increase at 2 days was an independent predictor of restenosis. Using receiver operator characteristic analysis, >25% postangioplasty increase of monocyte chemoattractant protein-1 was significantly associated with restenosis after percutaneous transluminal angioplasty (hazard ratio, 5.36; 95% confidence interval, 1.81 to 15.8).

CONCLUSIONS

Circulating monocyte chemoattractant protein-1 levels were elevated 2 days and 2 weeks after percutaneous transluminal angioplasty. Early postangioplasty increase of monocyte chemoattractant protein-1 level was associated with restenosis of arteriovenous fistulas.

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.

Usefulness of paclitaxel-releasing high-pressure balloon associated with cutting balloon angioplasty for treatment of outflow stenoses of failing hemodialysis arteriovenous shunts

AIM

To evaluate the technical and clinical success, primary patency (PP) and complications of angioplasty performed with paclitaxel-coated balloon (PCBs) associated with cutting balloon and for the treatment of the outflow stenoses of failing hemodialysis arteriovenous shunt.

MATERIAL AND METHODS

From September 2014 to September 2015, 50 patients with 66 stenoses were registered. Vascular accesses were autogenous (n = 20) and prosthetic (n = 30). Stenosis were documented during follow-up with routine echo-color Doppler, clinical evaluation and in the remaining incidentally during fistulography. Angioplasty was performed with cutting balloon and afterward with PCB. The mean follow-up time was 8 months (range 6-15 months). Technical success, clinical success, primary patency and complications were registered.

RESULTS

Technical success was 100 %. Clinical success was 94.7 %. Primary patency rate was 87.7 %; in five patients, a significant re-stenosis (≥50 %) was registered. A residual asymptomatic stenosis (<30 %) was registered in four cases (7 %). No major complications were registered.

CONCLUSIONS

A short-term patency benefit may be obtained including PCB in angioplasty treatment of failing hemodialysis arteriovenous shunts.

Outcomes of different treatments on Takayasu's arteritis

BACKGROUND

Takayasu's arteritis (TA) is a nonspecific chronic inflammation of the aorta and its branches. This study compared the outcomes of surgical treatments including bypass surgery, cutting balloon angioplasty and conventional balloon angioplasty to TA patients exhibiting supra-aortic arterial (SAA).

METHODS

This retrospective study was conducted on 42 TA patients, obtained from hospital database, who underwent surgical therapy due to SAA lesions from January 2010 to March 2015. Ten patients were reconstructed using cutting balloon angioplasty, 16 patients received conventional balloon angioplasty and 16 patients from bypass surgery. The primary patency, recurrent symptoms, re-intervention, early (<30 days) and late complications associated with treatment were evaluated.

RESULTS

In the conventional balloon angioplasty group, two patients were converted to bypass surgery as the guidewire could not traverse the lesions. The follow-up at 30.07±17.96 months (range, 1-60 months) showed restenosis or occlusion development in 40.9% arteries in conventional balloon angioplasty, compared with 6.3% after bypass surgery (P=0.018). The restenosis or occlusion rate between cutting balloon angioplasty and conventional balloon angioplasty groups were insignificant (P=0.738). In the re-intervention, three out of four (75%) treated by cutting balloon angioplasty were patent as compared to the three out of nine arteries (33.3%) dealt with by conventional angioplasty that was patent (P=0.266). Intracerebral hemorrhage (n=1) was developed in the bypass surgery group. Mortality was not observed in any of the groups.

CONCLUSIONS

Cutting balloon angioplasty can be considered as a safe, effective, and less-invasive alternative for non-diffuse SAA lesions, especially in young TA patients. However, bypass surgery has better primary patency rate than endovascular treatment.

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.

The use of a cutting balloon in contemporary reverse controlled antegrade and retrograde subintimal tracking (reverse CART) technique

The key concept of reverse controlled antegrade and retrograde tracking (CART) technique is retrograde puncture with a tapered wire to an antegrade balloon (contemporary reverse CART) or new connections between the antegrade and retrograde subintimal space (classical reverse CART). In our case, a 75-year-old man with severe chronic total occlusion of the right coronary artery, reverse CART with conventional balloons could not be accomplished. Externalization wiring was completed by contemporary reverse CART using a cutting balloon as an antegrade balloon to improve the fenestration force of the retrograde guidewire. Thus, the use of a cutting balloon for contemporary reverse CART might be promising.

Technology innovation for patients with kidney disease

The loss of kidney function is a life-changing event leading to life-long dependence on healthcare. Around 5000 people are diagnosed with kidney failure every year. Historically, technology in renal medicine has been employed for replacement therapies. Recently, a lot of emphasis has been placed on technologies that aid early identification and prevent progression of kidney disease, while at the same time empowering affected individuals to gain control over their chronic illness. There is a shift in diversity of technology development, driven by collaborative innovation initiatives such the National Institute's for Health Research Healthcare Technology Co-operative for Devices for Dignity. This has seen the emergence of the patient as a key figure in designing technologies that are fit for purpose, while business involvement has ensured uptake and sustainability of these developments. An embodiment of this approach is the first successful Small Business Research Initiative in the field of renal medicine in the UK.

Dialysis Access Anatomy and Interventions: A Primer

The creation of arteriovenous fistulae and the use of arteriovenous grafts are a vital component in the treatment of patients undergoing dialysis. For many patients in this population, these accesses represent the permanent solution to their dialysis needs. Understanding the basic anatomy of the most common accesses used, as well as initial treatment of many underlying causes of access failure is vital for any interventionalist performing such procedures. This article outlines the most common approaches to surgically placed accesses used for renal replacement therapy, as well as the basics of interventional approaches used to treat the most common abnormalities causing their dysfunction.

Postintervention Patency Rates and Predictors of Patency after Percutaneous Interventions on Intragraft Stenoses within Failing Prosthetic Arteriovenous Grafts

PURPOSE

To determine postintervention patency rates after endovascular interventions on intragraft stenosis within failing prosthetic arteriovenous (AV) grafts, as well as predictors of patency.

MATERIALS AND METHODS

Retrospective review of percutaneous interventions on prosthetic AV grafts presenting with first-time intragraft stenoses over a 7-year period revealed 183 patients (81 male; mean age, 59.7 y). "Intragraft" was defined as 2 cm or more from the arterial or venous anastomosis. Procedural imaging was retrospectively reviewed. Patency rates were estimated by Kaplan-Meier test. Predictors of patency were calculated by Cox proportional-hazards model.

RESULTS

Two-hundred twenty-nine intragraft stenoses were identified in 183 grafts. Intragraft stenoses were treated at a median of 20.7 months (interquartile range, 12.0-33.9 mo) after graft creation. Graft thrombosis was present in 62%. The anatomic success rate of angioplasty was 85%. Fifteen percent required stent or stent-graft deployment because of inadequate response to angioplasty. A concurrent nonintragraft stenosis within the access circuit was identified in 76% of grafts. At 3, 6, and 12 months, postintervention primary patency rates were 56%, 40%, and 23%, respectively. Secondary patency rates were 84%, 77%, and 67%, respectively. The lesion-specific patency rates were 89, 75%, and 63%, respectively. Graft thrombosis (hazard ratio [HR], 1.43; P = .048) and concurrent nonintragraft lesion (HR, 1.51; P = .047) were independent negative predictors of primary patency. Graft thrombosis (HR, 1.81; P = .029) was a negative predictor of lesion patency, and stent or stent-graft deployment (HR, 0.42; P = .045) was a positive predictor of lesion patency.

CONCLUSIONS

Endovascular interventions on intragraft stenoses resulted in primary, secondary, and lesion-specific patency rates of 40%, 77%, and 75%, respectively, at 6 months. Stent or stent-graft deployment may prolong lesion patency.

Percutaneous Transluminal Angioplasty in Japan: Five-Center Investigation

Purpose

Percutaneous transluminal angioplasty (PTA) is the first-line treatment for vascular access stenosis. To our knowledge, multicenter clinical research of PTA has not been reported in Japan. We examined the efficacy and safety of PTA for arteriovenous fistula (AVF) and arteriovenous graft (AVG) in five centers of Japan.

Methods

Three hundred cases of angioplasty for AVF and 300 for AVG were examined in three centers each. A hundred consecutive patients from each center who underwent PTA for AVG or AVF prior to March 2014 and met the inclusion criteria were searched retrospectively. Primary patency rates were estimated using the Kaplan-Meier method.

Results

The mean age was 69.3 ± 11.2 years in the AVF group and 70.2 ± 11.9 years in the AVG group. The anatomical success rates were 51.7% (155 of 300) in the AVF group and 72.0% (216 of 300) in the AVG group. The clinical success rates were 99.7% (299 of 300) in the AVF group and 100% (300 of 300) in the AVG group. A total of 25 complications (4.17%) were encountered in both groups including one major complication (0.17%). The primary patency was 99.0% at 1 month, 87.9% at 3 months and 51.7% at 6 months in the AVF group, and 96.0% at 1 month, 64.8% at 3 months and 20.4% at 6 months in the AVG group.

Conclusions

The clinical success rate of PTA in five centers was relatively high and a major complication rate was only 0.17%. However, anatomical success rates were low comparing with the previous studies and the primary patency rates were inferior to the past data.