Balloon angioplasty vs nitinol stent placement in the treatment of venous anastomotic stenoses of hemodialysis grafts after surgical thrombectomy

Existing and Evolving Therapies for Arteriovenous Fistula and Graft Dysfunction

A functional vascular access (VA) is of paramount importance to patients on hemodialysis therapy. While arteriovenous fistula (AVF) remains the preferred VA, their long-term patency is unpredictable. A dysfunctional VA contributes to a high morbidity rate, an increased susceptibility to major adverse cardiovascular events, recurrent hospitalization, and a poor quality of life. The recent innovations in devices and technologies have significantly expanded our options to create and prolong VA patency. Endovascular devices such as WavelinQ and Ellipsys are recent additions to creating a VA. The endovascular creation of AVF helps reduce the wait time and potentially avoids or reduces the duration of catheter use. The bioengineered graft and immediate access arteriovenous graft offer reasonable alternatives in a select group of patients. There is growing evidence that covered stents and drug-coated balloons offer options to prolong the VA patency. Finally, the role of stem cell therapy in VA is currently being explored. This article presents a comprehensive review of the conventional and current developments in the management of a dysfunctional VA.

Bare-Metal Stent in Dysfunctional Hemodialysis Access: An Assessment of Circuit Patency according to Access Type and Stent Location

Purpose

To evaluate the circuit patency after nitinol bare-metal stent (BMS) placement according to the type of access and location of the stent in dysfunctional hemodialysis access.

Materials and Methods

Between January 2017 and December 2019, 159 patients (mean age, 64.1 ± 13.2 years) underwent nitinol BMS placement for dysfunctional access. The location of stents was as follows: 18 brachiocephalic vein, 51 cephalic arch, 40 upper arm vein, 10 juxta-anastomotic vein, 7 arteriovenous (AV) anastomosis, and 33 graft-vein (GV) anastomosis. Circuit patency was evaluated by the Kaplan-Meier method, and cox regression model.

Results

A total of 159 stents were successfully deployed in 103 AV fistula (AVF) and 56 AV graft (AVG). AVG showed lower primary and secondary patency at 12-months compared with AVF (primary patency; 25.0% vs. 44.7%; p = 0.005, secondary patency; 76.8% vs. 92.2%; p = 0.014). Cox regression model demonstrated poorer primary patency at 12 months after stenting in the cephalic arch and GV anastomosis compared with the other sites.

Conclusion

AVF showed better primary and secondary circuit patency at 12 months following the placement of BMS compared with AVG. Stents in the cephalic arch and GV anastomosis were associated with poorer primary patency at 12 months compared to those in other locations.

Comparison of Clinical Outcomes in Patients Undergoing a Salvage Procedure for Thrombosed Hemodialysis Arteriovenous Grafts

Background

The major limitation of arteriovenous graft access is the high incidence of thrombotic occlusion. This study investigated the outcomes of our salvage strategy for thrombosed hemodialysis arteriovenous grafts (including surgical thrombectomy with balloon angioplasty) and evaluated the efficacy of intragraft curettage.

Methods

Salvage operations were performed for 290 thrombotic occluded arteriovenous grafts with clinical stenotic lesions from 2010 to 2018. Of these, 117 grafts received surgical thrombectomy and balloon angioplasty from 2010 to 2012 (group A), and 173 grafts received surgical thrombectomy and balloon angioplasty, with an additional salvage procedure using a curette and a graft thrombectomy catheter, from 2013 to 2018 (group B). Outcomes were described in terms of post-intervention primary patency and secondary patency rates.

Results

The post-intervention primary patency rates in groups A and B were 44.2% and 66.1% at 6 months and 23.0% and 38.3% at 12 months, respectively (p=0.003). The post-intervention secondary patency rates were 87.6% and 92.6% at 6 months and 79.7% and 85.0% at 12 months, respectively (p=0.623). Multivariate Cox regression analysis demonstrated that intragraft curettage was a positive predictor of post-intervention primary patency (hazard ratio, 0.700; 95% confidence interval, 0.519-0.943; p=0.019).

Conclusion

Surgical thrombectomy and balloon angioplasty showed acceptable outcomes concerning post-intervention primary and secondary patency rates. Additionally, intragraft curettage may offer better patency to salvage thrombotic occluded arteriovenous grafts with intragraft stenosis.

Comparable Patency of Open and Hybrid Treatment of Venous Anastomotic Lesions in Thrombosed Haemodialysis Grafts

OBJECTIVE

Arteriovenous graft (AVG) failures are typically associated with venous anastomotic (VA) stenosis. Current evidence regarding AVG thrombosis management compares surgical with purely endovascular techniques; few studies have investigated the "hybrid" intervention that combines surgical balloon thrombectomy and endovascular angioplasty and/or stenting to address VA obstruction. This study aimed to describe outcomes after hybrid intervention compared with open revision (patch venoplasty or jump bypass) of the VA in thrombosed AVGs.

METHODS

Retrospective cohort study. Consecutive patients with a thrombosed AVG who underwent thrombectomy between January 2014 and July 2018 were divided into open and hybrid groups based on VA intervention; patients who underwent purely endovascular thrombectomy were excluded. Patient demographics, previous access history, central vein patency, AVG anatomy, type of intervention, and follow up data were recorded. Kaplan-Meier curves were used to analyse time from thrombectomy to first re-intervention (primary patency) and time to abandonment (secondary patency). Cox regression analysis was performed to evaluate predictors of failure.

RESULTS

This study included 97 patients (54 females) with 39 forearm, 47 upper arm, and 11 lower extremity AVGs. There were 34 open revisions (25 patches, nine jump bypasses) and 63 hybrid interventions, which included balloon angioplasty ± adjunctive procedures (15 stents, five cutting balloons). Technique selection was based on physician preference. Primary patency for the open and hybrid groups was 27.8% and 34.2%, respectively, at six months and 17.5% and 12.9%, respectively, at 12 months (p = .71). Secondary patency was 45.1% and 38.5% for open and hybrid treatment, respectively, at 12 months (p = .87). An existing VA stent was predictive of graft abandonment (hazard ratio 4.4, 95% confidence interval 1.2-16.0; p = .024). Open vs. hybrid intervention was not predictive of failure or abandonment.

CONCLUSION

Hybrid interventions for thrombosed AVGs are not associated with worse patency at six and 12 months compared with open revision.

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.

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.

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.

Long-term outcomes of bovine pericardial patch angioplasty for recurrent stenosis in vascular access: A UK single-centre experience

INTRODUCTION:

Stenosis of an arteriovenous fistula or arteriovenous graft for dialysis is a common problem. Stenosis may lead to a number of problems including failure of the fistula. Treatment of stenosis is commonly with percutaneous angioplasty or surgical patch angioplasty with autologous vein or synthetic graft or patch. Here we report the use of bovine pericardial patch angioplasty as an alternative mode of patch angioplasty when percutaneous intervention has failed.

METHODS:

Patients with fistulae treated with bovine patch angioplasty between 2013 and 2016 were identified from a prospectively maintained renal access database (Cyberren^®). Patient records were reviewed, noting type and location of access, patency, re-interventions and complications post bovine pericardial patch.

RESULTS:

A total of 40 patients were identified as having undergone bovine pericardial patch angioplasty between January 2013 and April 2016. The median time from fistula formation to bovine pericardial patch was 15 months (interquartile range (IQR): 5-43). Median duration of follow-up was 14 months (IQR: 5-18). Primary patency at 6, 12, 18 and 24 months was 91%, 66%, 61% and 54%, respectively. Secondary patency was 94%, 91%, 80% and 77% at the same time points, respectively. In total, 15 patients required 23 re-interventions post bovine pericardial patch. There has been no report of infection or aneurysm formation.

CONCLUSION:

Bovine pericardial patch angioplasty for recurrent stenosis in arteriovenous fistulae for dialysis access provides a robust alternative to other surgical patches with the added advantage of allowing early needling and relative resistance to infection. Rates of restenosis and failure post bovine pericardial patch are low.

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.

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.

Clinical Course of Hemodialysis Access After Initial Endovascular Intervention for Stenosis in Asian Renal Failure Patients

BACKGROUND

Arteriovenous fistula (AVF) and arteriovenous fistula graft (AVG) access for hemodialysis can develop stenosis, eventually leading to thrombosis and access failure. Prompt endovascular intervention can salvage the access but restenosis does occur. Clinical course, restenosis pattern, and risk factors associated with initial stenosis of AVFs/AVGs in Asian hemodialysis patients were studied.

METHOD

A retrospective study was conducted (January 2009-June 2012) on consecutive patients with renal failure who developed the first-time stenosis in the vascular access and were managed with endovascular intervention. One hundred fourteen patients (54 AVFs and 60 AVGs) were studied, and all clinical outcomes were recorded until October 2013.

RESULTS

The mean time from access creation to endovascular intervention for the first-time stenosis for patients with AVF and AVG was 23.5 (32.7 standard deviation [SD]) months and 12.5 (11.0) months, respectively. An average of 1.7 (range, 1-5) interventions were performed for AVFs, whereas 2.4 (range, 1-11) for AVGs ( P = .008). Upon conclusion of the study, 23 patients with AVF survived with functional index access, whereas 10 passed away with a functional original access. The remaining 21 patients with AVFs failed, requiring new access, tunneled catheter, or peritoneal dialysis. Of the 60 patients with AVG, 6 survived and 8 died with functional index access; 46 required new access or other forms of dialysis ( P = .000). Kaplan-Meier estimated that access patency and survival with functional access were significantly lower for AVGs than for AVFs after the first salvage intervention. Female patients had an increased risk of restenosis with both univariate ( P = .016) and multivariate ( P = .013) analysis. With univariate analysis ( P = .039), patients with hyperlipidemia had a higher risk of developing restenosis in the vascular access.

CONCLUSION

The clinical course and prognosis of failing AVFs and AVGs are distinct. The information on access prognosis and stenosis recurrence patterns will be helpful for patient counseling and planning of follow-up intervals, after the first-time intervention for access stenosis.

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

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

Initiation of antiplatelet medication after surgical thrombectomy jeopardized arteriovenous graft longevity

INTRODUCTION

The efficacy of antiplatelet agents in preventing thrombosis in newly formed arteriovenous graft (AVG) in hemodialysis (HD) patients has been extensively examined. The aim of this study was to investigate the possible effect of initiation of antiplatelet medications on preventing AVG thrombosis recurrence after surgical thrombectomy for acute occlusion in HD patients. Whether post-operatively antiplatelet medications have protective effects on the patency or longevity of AVG after surgical thrombectomy in HD patients has not been investigated.

METHODS

We conducted a 4-year quasi-randomized study of the unassisted patency and AVG longevity for 213 HD patients with or without initiating antiplatelet drugs after receiving surgical thrombectomy for first episode of acute AVG thrombosis.

RESULTS

From the propensity-score-matched quasi-randomized study, initiation of antiplatelet drugs after first surgical thrombectomy in HD patients did not prevent the recurrence of surgical thrombectomy (log-rank p = 0.81), but significantly decreased the longevity of the access (log-rank p = 0.034). Multivariate Cox model demonstrated that prescription of antiplatelet drugs significantly increased the risk of graft failure (adjusted hazard ratio 2.13, p = 0.025).

CONCLUSIONS

Adjunctive prescription with antiplatelet medications in HD patients after surgical thrombectomy did not prevent recurrent thrombosis of AV access, but significantly jeopardized the longevity of AVG after surgical thrombectomy.

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.

Advanced Stent Graft Treatment of Venous Stenosis Affecting Hemodialysis Vascular Access: Case Illustrations

Surgically placed dialysis access is an important component of dialysis replacement therapy. The vast majority of patients undergoing dialysis will have surgically placed accesses at some point in the course of their disease, and for many patients these accesses may represent their definitive renal replacement option. Most, if not all, arteriovenous fistulae and grafts will require interventions at some point in time. Percutaneous angioplasty is the typical first treatment performed for venous stenoses, with stents and stent grafts being reserved for patients in whom angioplasty and surgical options are exhausted. In some salvage situations, stent graft placement may be the only or best option for patients. This article describes, using case illustrations, placement of stent grafts in such patients; a focus will also be made on the techniques utilized in such salvage situations.

The Eternal Tale of Dialysis Access Vessels and Restenosis: Are Drug-Eluting Balloons the Solution?

In dialysis access fistulas and grafts, percutaneous transluminal angioplasty (PTA) is frequently followed by restenosis development, which results in repeated periodical re-interventions. The technique of drug-eluting balloon (DEB) angioplasty has shown promising results in the treatment of femoropopliteal arteriosclerotic lesions. In contrast to arteriosclerotic arteries, dialysis access vessels host unfavorable hemodynamics due to the direct conduction of high-pressure fluid into a low-pressure system. Hence, the beneficial effect of DEB angioplasty may be limited in this system. However, a first prospective randomized trial on 40 patients with arteriovenous fistula or graft stenoses exhibited a significantly higher 6-month primary patency of the treated lesions after DEB angioplasty than after uncoated balloon angioplasty. Despite such a positive reference, general recommendations regarding the value of DEBs in dialysis access vessels cannot be considered as serious unless large randomized controlled trials have been performed.

Arteriovenous graft for hemodialysis, graft venous anastomosis closure - current state of knowledge. Minireview

Backround. The use of artificial vascular grafts (arteriovenous graft, AVG) is indicated in patients in hemodialysis programs if the subcutaneous venous bed is exhausted or unsuitable for arteriovenous fistula (AVF) creation. The native fistula should be the hemodialysis access of first choice: AVF has better results in terms of function and potential complications. However, the use of AVG is necessary in some patients. In these patients, extensive clinical examination, color duplex sonography and angiography should be performed prior to indication. The technique of graft implantation requires respect for geometric relations for the graft anastomoses to minimize the formation of intimal hyperplasia mainly on the venous anastomosis. The main complications of AVG are stenosis on the venous anastomosis (VAG), causing closure of graft and graft infection. The cumulative function of AVG is 59-90% in the first year and 50-82% in the second year. Arteriovenous graft stenosis leading to thrombosis is a major cause of complications in patients undergoing hemodialysis. The purpose of this review is to summarise current knowledge of the diagnostics and treatment of graft thrombosis and discuss the issue in combination with relevant publications via Pubmed database.

CONCLUSION

The most frequent cause of failure of AVG for hemodialysis is stenosis and closure by VAG. AVG closure can be addressed surgically, endovascularly (amenable to thrombectomy by radiological or surgical means) and by hybrid performance.

Treatment of hemodialysis vascular access arteriovenous graft failure by percutaneous intervention

A patent vascular access is the lifeline of end-stage renal disease patients depending on hemodialysis treatment. Once a functioning vascular access has been established, maintaining its patency is of utmost importance. During the last decades percutaneous techniques became increasingly important for the treatment of hemodialysis vascular access graft failure. In this review, the role of percutaneous balloon angioplasty and stent implantation is evaluated for different clinical scenarios, based on the available evidence.

Hybrid Simultaneous Treatment of Thrombosed Prosthetic Grafts for Hemodialysis

Purpose

The aim of the study was to evaluate our experience in the hybrid simultaneous treatment (open and endovascular) of acute thrombosis of prosthetic grafts for hemodialysis.

Methods

Between January 2011 and June 2013, 23 patients with acute thrombosis of a prosthetic graft for hemodialysis were urgently treated with a hybrid simultaneous treatment in order to obtain a prompt restoration of the flow. A new puncture of the graft was scheduled after 24 hours.

Results

Intraoperative technical success was 100% with a completion angiography showing the restored patency of the graft. As adjunctive procedures, in 6 patients (26.1%) locoregional thrombolysis was necessary and in all cases further endovascular manoeuvres (angioplasty/stenting) were immediately performed to solve a significant stenosis of the venous anastomosis/first tract of the vein. At 24 hours when the first puncture was done, three grafts were occluded resulting in a primary patency of 87%. During the follow-up (mean duration 5.6 months) four reocclusions occurred. In-stent restenosis occurred in all patients undergone stenting. At 1 year the rates of primary patency, primary assisted patency and secondary patency were 58.7%, 78.3% and 87%, respectively.

Conclusions

In our series the combined simultaneous hybrid approach in urgency maximizes the use of different available techniques, which appeared to improve overall success rate to save a thrombosed graft for hemodialysis. The great difference showed between primary and primary assisted patency demonstrates the necessity of a close follow-up.

Novel therapies for hemodialysis vascular access dysfunction: myth or reality?

Hemodialysis vascular access dysfunction is a major source of morbidity for patients with ESRD. Development of effective approaches to prevent and treat vascular access failure requires an understanding of the underlying mechanisms, suitable models for preclinical testing, systems for targeted delivery of interventions to maximize efficacy and minimize toxicity, and rigorous clinical trials that use appropriate outcome measures. This article reviews the substantial progress and ongoing challenges in developing novel treatments for arteriovenous vascular access failure and focuses on localized rather than systemic interventions.

Early outcomes of the intraluminal flow guard device for secondary renal access

PURPOSE

The Flixene Intraluminal Flow Guard (IFG) is a novel arteriovenous graft for use in complex renal access patients. The IFG is a PTFE graft with a covered nitinol stent at the venous end implanted into the axillary vein rather than anastomosed. The purported benefits are improved hemodynamic flow in the vein with reduced neointimal hyperplasia. Our primary aim was to assess its early patency and complications. Our center is the first to publish early outcomes.

METHODS

All patients on whom we would have otherwise performed a standard brachial-axillary graft from April to November 2011 were instead given an IFG graft if they were suitable and consented. The only exclusion criteria was an axillary vein size under 5.5 mm as this would not accommodate the intraluminal stent graft. Data were collected prospectively and follow-up was identical to our usual graft surveillance.

RESULTS

A total of 12 patients (mean age 64, mean follow-up 393 days) had IFG grafts implanted during the study period. There were no exclusions and all patients consented. All patients were having secondary access following previous failed fistulae or grafts and no patient had an autogenous hemodialysis option. On average each patient had already had 1.1 previous ipsilateral access procedures. Mean operating time was 109 minutes. Functional patency at one year was 65.6%, with a mean functional patency of 162 days. There was only one early complication (wound hematoma) and one graft infection requiring explantation.

CONCLUSIONS

The IFG device provides an alternative to standard brachial-axillary grafts and brings similar early patency and complication profile. Continued monitoring of outcomes, however, is required to determine long-term results.