Treatment of failed native arteriovenous fistulae for hemodialysis by interventional radiology

Endovascular Thrombectomy of Arteriovenous Dialysis Access: A Feasible Treatment?

INTRODUCTION

There is no single best treatment for arteriovenous vascular access thrombosis, with comparable patency rates for both surgical and endovascular treatment. This study aims to evaluate the results of endovascular thrombectomy in our center and analyze the patency rates in different groups.

MATERIAL AND METHODS

We retrospectively selected patients referred to our vascular access treatment unit due to arteriovenous access thrombosis from June 2017 to February 2022. All patients were submitted to endovascular manual thromboaspiration. Patient demographic data, comorbidities and clinical data were collected from medical records for further analysis.

RESULTS

Out of the 96 patients selected, 45 (47%) had AV grafts and 51 (53%) had AV fistulas. The mean age was 74 (±15) years and 54% were males. The overall success rate of interventions was 85.4% (n = 82), while the reintervention rate stood at 59.8% (n = 49). AV grafts exhibited superior secondary patency compared to AV fistulas (92.4% vs. 78.0% and 85.3% vs. 74.1% at 6 and 12 months, respectively; p = 0.047). Forearm fistulas demonstrated enhanced primary patency (72.7% vs. 41.5% and 58.2% vs. 23.1% at 6 and 12 months, respectively; p = 0.017), better assisted primary patency (81.8% vs. 55.8% and 81.8% vs. 42.0% at 6 and 12 months, respectively; p = 0.025), and a lower reintervention rate (27.3% vs. 63.3%; p = 0.040) compared to upper arm fistulas.

CONCLUSIONS

Endovascular manual thromboaspiration seems to be an alternative technique for salvaging thrombosed vascular accesses. Forearm fistulas had the best assisted primary patency, which consolidates the rationale of giving primacy to its construction over other options.

Editor's Choice - A Systematic Review and Meta-analysis of 24 Month Patency After Endovenous Stenting of Superior Vena Cava, Subclavian, and Brachiocephalic Vein Stenosis

OBJECTIVE

This systematic review and meta-analysis aimed to appraise recent evidence assessing patency outcomes at various time points in patients with superior vena cava, subclavian, and brachiocephalic vein stenosis who had undergone stenting.

DATA SOURCES

PubMed, Scopus, and Cochrane Library databases were searched for studies up to December 2022.

REVIEW METHODS

Measured outcomes included technical success rate, primary, primary assisted, and secondary patency at various time points. A subgroup analysis was also conducted to compare malignant and benign obstruction. GRADE was used to assess the certainty of evidence.

RESULTS

Thirty nine studies reporting outcomes in 1 539 patients were included in the meta-analysis. Primary patency up to one year after the procedure was 81.5% (95% CI 74.5 - 86.9%). Primary patency declined after one year to 63.2% (95% CI 51.9 - 73.1%) at 12 - 24 months. Primary assisted patency and secondary patency at ≥ 24 months were 72.7% (95% CI 49.1 - 88.0%) and 76.6% (95% CI 51.1 - 91.1%). In the subgroup analysis, primary patency was significantly higher in patients with a malignant stenosis compared with a benign stenosis at 1 - 3 and 12 - 24 months. No significant difference was seen for pooled secondary patency rates when comparing the malignant and benign subgroups. GRADE analysis determined the certainty of evidence for all outcomes to be very low.

CONCLUSION

Stenting is an effective intervention for benign and malignant stenosis of the superior vena cava, subclavian, and brachiocephalic veins. Primary patency rates were good up to one year after the procedure, with 81.5% of stents retaining patency at 6 - 12 months. Patency rates declined after one year, to 63.2% primary and 89.3% secondary patency at 12 - 24 months, showing improved outcomes following re-intervention. High quality evidence is lacking. More research is needed to investigate patency outcomes and the need for surveillance or re-intervention programs.

Feasibility of an antegrade-retrograde single-sheath inverse technique via vertical puncture in dysfunctional hemodialysis arteriovenous fistula angioplasty

BACKGROUND

Stenosis resulting in dysfunctional dialysis access may occur simultaneously on the anastomotic and central venous side. The purpose of this study was to retrospectively evaluate the feasibility of a single sheath inverse technique using the vertical puncture approach to perform bidirectional transvenous percutaneous transluminal angioplasty (PTA) from a single sheath for such dialysis access stenoses.

MATERIALS AND METHODS

Twenty patients (26 cases; 13 males; median age, 74 [range: 50-89] years) who underwent PTA using the sheath inverse technique for dysfunctional arteriovenous fistula stenoses between April 2019 and June 2023 were included. All procedures were performed in an outpatient setting. A 4-cm sheath (4Fr, four cases; 5Fr, 19 cases; 6Fr, three cases) was inserted by vertical puncture through a cutaneous vein in the forearm (20 cases) or upper arm (six cases). After treating one side of the lesion, the sheath was reversed to treat the lesion on the opposite side. The vessel diameter at the sheath insertion site, the success rate of sheath inversion, the number of PTA balloon catheters used, the PTA success rate, adverse events, and primary and secondary patency rates up to one year after PTA were evaluated.

RESULTS

The median diameter at the sheath indwelling site was 5.2 (range: 3.6-9.5) mm, and sheath inversion was successful in all cases, eliminating the need to place an additional sheath at another site for contralateral stricture treatment. The number of balloon catheters used was one and two in 17 (65%) and eight cases (31%), respectively, and three in one case wherein a drug-coated balloon was used. PTA was successful in all cases and major complications were not observed. However, in one case wherein a sheath had to be placed at the arterial needle puncture site, the skin was hard, leading to difficulty in inversion, and transient venous spasm occurred post-inversion. The primary patency rates at 3, 6 and 12 months after the PTA were 87.5%, 41.7%, and 20.8%, respectively. The secondary patency rates at 6 and 12 months were 100% and 75%, respectively.

CONCLUSION

The single-sheath inverse technique for arteriovenous fistulas was feasible without sheath withdrawal.

Outcomes of prosthetic upper arm arteriovenous graft vs brachiobasilic fistula for hemodialysis access

OBJECTIVE

Primary arteriovenous access such as radiocephalic and brachiocephalic fistulas are initial choices for creating vascular access in dialysis patients. When neither of these choices is an option, upper arm arteriovenous graft or brachiobasilic transposition is recommended. Although primary fistula is better than prosthetic graft for suitable patients, there is little data to guide the best treatment strategy in the absence of suitable vein for primary access creation. This study identifies factors that influence patency rates and compares outcomes of patients treated with brachiobasilic fistula vs upper arm graft in patients who have failed forearm access or are not candidates for primary access.

METHODS

A prospectively maintained database of patients with dialysis-dependent renal failure from 2010 to 2022 was analyzed. Primary, primary assisted, and secondary patency rates were calculated. Incidence rates of complications and reinterventions were compared.

RESULTS

There were 148 patients with brachiobasilic fistulas and 157 patients with upper arm grafts. The graft group was older (70.1 ± 14.7 vs 62.5 ± 14.6 years; P = .003) and had a higher incidence of pacemakers (11.9% vs 4.1%; P = .005). Brachiobasilic fistulas had higher 6-month (77.0% vs 64.3%; P = .02) and 1-year (68.2% vs 55.4%; P = .03) primary-assisted patency. Secondary patency rates were better for upper arm grafts at 1-year (82.2% vs 72.3%; P = .05). Access complications of non-maturation and aneurysm were higher in basilic vein transposition (21.6% vs 1.3%; P < .0001; 15.5% vs 6.4%; P = .017). Grafts had higher rates of occlusion (58.0% vs 25.7%; P < .0001). In terms of interventions, upper arm grafts had higher rates of thrombectomy (50.3% vs 18.9%; P < .0001), but there was no difference seen in angioplasty, stent, surgical revision, or steal procedures. Basilic vein transpositions had longer time to cannulation (104.6 ± 81.1 vs 32.5 ± 22.4 days; P < .0001), longer total catheter days (251.1 ± 181.7 vs 72.9 ± 56.3 days; P < .0001), and higher number of procedures to aid maturity (0.7 ± 0.7 vs 0.1 ± 0.3; P < .0001).

CONCLUSIONS

In this retrospective analysis, when forearm access or primary arteriovenous access is not an option, basilic vein transposition and upper arm grafts have fairly equivalent primary patency. Primary assisted patency is slightly better in basilic vein fistulas, but secondary patency is better in upper arm grafts at 1 year. Basilic fistulas also had longer time to cannulation, longer total catheter days, and more procedures to aid maturity.

Double guidewire technique (DGT): Optimising endovascular revision of juxta-anastomotic stenosis in AV-fistulae: A retrospective analysis

BACKGROUND

Arteriovenous fistula (AVF) is the preferred angioaccess for haemodialysis but suffers from a high stenosis rate, juxta-anastomotic stenosis (JAS) being the most frequent. Percutaneous transluminal angioplasty (PTA) of JAS would have some advantage (such as mini-invasive and vein sparing treatment), but higher recurrence rate is observed as compared to surgery. We report results of juxta anastomotic stenosis PTA using the 'double guide technique' (DGT) as described by Turmel-Rodrigues, in a selected cohort from our Vascular Access Centre.

PATIENTS AND METHODS

From January to June 2018, 25 consecutive patients were treated by DGT. By means of retrograde access through the outflow vein by a 6 F introducer, two guide wires were navigated: one into proximal radial artery (GW1), the other into distal artery (GW2). GW2 was used to dilate juxta-anastomotic vein and anastomotic area with 6 mm high-pressure balloon, while by GW1 juxta-anastomotic artery was dilated with 4 mm semi-compliant balloon. Mean diameter of balloons were 6.7 and 4.1 mm for venous and arterial tract dilatation. Follow up was carried out up to 12 months. Prospectively collected data were analysed retrospectively.

RESULTS

One-year primary and secondary patency was 52% and 95% respectively. Recurrence rate was 0.56 procedure/pt/year. Mean access blood flow at 12 months was 830 ml/min.

CONCLUSION

Double Guidewire Technique is an effective and minimally invasive procedure. By avoiding under dilation of JAS the recurrence rate resulted quite satisfactorily in our population.

Dialysis Access Maintenance: Plain Balloon Angioplasty

Plain balloon angioplasty remains the first-line treatment for dialysis access stenosis. This chapter reviews the outcomes of plain balloon angioplasty from cohort studies and comparative studies. Angioplasty outcomes are more favourable in arteriovenous fistulae (AVF) compared to arteriovenous grafts (AVG) with primary patency at 6 months ranging from 42-63% compared to 27-61%, respectively, and improved for forearm fistulae compared with upper arm fistulae. Higher pressures are required to treat stenoses in AVFs compared to AVGs. Outcomes are worse in more severe stenoses, increased patient age, previous interventions and fistulae that develop early stenoses. Major complication rates following angioplasty in dialysis access are between 3 and 5%. Repeat treatments and the use of adjuncts such as drug-coated balloons and stents can prolong the patency of dialysis access. Level of Evidence No level of evidence (Review paper).

Removal of Wall-Adherent Inferior Vena Cava Thrombus with a Combined Approach Using Vacuum-Assisted Thrombectomy and a Rotational Thrombectomy Device

Introduction. Large thrombi in the inferior vena cava pose a high risk for a pulmonary embolism. Percutaneous extracorporeal circulation-based vacuum-assisted thrombus aspiration is a viable option for removal. Wall adherence of thrombotic material can compromise procedural success. Case Report. A 46-year-old female presented with a subtotal thrombotic occlusion of the inferior vena cava and the proximal right common iliac vein after weaning from extracorporeal life support. Due to severe wall adherence of the thrombotic material, the patient was treated with the combination of percutaneous extracorporeal circulation-based thrombus aspiration using the AngioVac system and a rotational thrombectomy device.

Outcomes of endovascular treatment for stenosis occurring after cephalic vein transposition and graft interposition

OBJECTIVE

To evaluate the outcome of endovascular treatment after surgical treatment for cephalic arch stenosis in brachiocephalic fistula and to analyze the factors influencing patency.

METHODS

We conducted a retrospective review of patients undergoing cephalic transposition (CVT) or graft interposition (GIP) for cephalic arch stenosis (CAS) from January 1, 2017, to December 31, 2019. A total of 73 patients with restenosis were included in this study. Patients were classified into cephalic transposition (BCF-CVT) (n=49) and graft interposition (BCF-GIP) (n=24) groups. We calculated the postintervention primary and secondary patency of endovascular treatment by using the Kaplan-Meier analysis and analyzed variables associated with loss of postintervention patency.

RESULTS

Six-month and 12 month postintervention primary patency rates of endovascular treatment for restenosis were 56.7% and 15.6% and secondary patency rates were 89.7% and 72.1%, respectively. In BCF-CVT group, six month, and 12 month postintervention primary patency was 56.8% and 17.6% and secondary patency was 93.3% and 79.4%, respectively. In BCF-GIP group, six-month, and 12 month postintervention primary patency was 56.5% and 8.7% and secondary patency was 85.7% and 56.3%, respectively. There was no significant difference in postintervention primary patency between the two groups (p=0.79). However, BCF-CVT group demonstrated higher postintervention secondary patency (p=0.034). BCF-GIP group had a higher number of stenosis sites (p<0.01). There was no significant predictor of reduced postintervention primary patency. The only adverse variable of postintervention secondary patency was BCF-GIP (Hazard ratio 3.14; 95% CI 1.06 to 9.34, p <0.05).

CONCLUSION

Endovascular treatment is still the acceptable option for stenosis occurring after surgical treatment for CAS. CVT provides higher postintervention secondary patency than GIP.

Results of Prompt Surgical Intervention in Hemodialysis Radiocephalic Fistula Secondary Dysfunction

Radiocephalic fistula (RCF) dysfunction is a common problem due to low maturation and patency rates of these fistulas. The most common procedure in such cases is to place a temporary catheter for the dialysis. Temporary catheter placement and undergoing dialysis with this catheter cause complications, reduce the chance for fistula, and deteriorate the quality of life. The aim of this study was to demonstrate that immediate intervention in RCF dysfunctions can increase fistula success for the patient and can reduce the need for a catheter. Furthermore, the hemodialysis treatment can continue without affecting the quality of life. A total of 295 patients who were admitted for RCF dysfunction and who underwent early surgical intervention without any catheter placement were evaluated for postoperative complications, patency rates, and rates and durations of temporary catheter use over a mean time of 47 months of follow-up (range: 4–79 months). Of the patients, 77.2% (n = 228) underwent new proximal anastomosis (NEO; the radial artery and cephalic vein were reached with an incision created proximal to the previous anastomosis), 14.2% (n = 42) underwent brachiocephalic arteriovenous fistula (AVF), 8.4% (n = 25) underwent side-to-side brachiobasilic AVF + superficialization of the basilic vein. In 88.8% (n = 262) of the patients, successful cannulations were performed within the first 24 to 48 hours without any catheter requirement or complications. Temporary catheter was used for 15.1 ± 10.7 days in 11.2% (n = 33) of the patients. In RCF dysfunctions, early surgical interventions performed in the forearm and elbow provide early cannulation and thus decrease the catheter requirement, also prevent the complications of temporary catheters (infection, decreasing the fistula success, vascular injuries, etc.), increase the autogenous fistula success, and allow for the continuation of dialysis without disturbing the quality of life.

The Anastomotic Angle of Hemodialysis Arteriovenous Fistula Is Associated With Flow Disturbance at the Venous Stenosis Location on Angiography

The juxta-anastomotic stenosis of an arteriovenous fistula (AVF) is a significant clinical problem in hemodialysis patients with no effective treatment. Previous studies of AV anastomotic angles on hemodynamics and vascular wall injury were based on computational fluid dynamics (CFD) simulations using standardized AVF geometry, not the real-world patient images. The present study is the first CFD study to use angiographic images with patient-specific outcome information, i.e., the exact location of the AVF stenotic lesion. We conducted the CFD analysis utilizing patient-specific AVF geometric models to investigate hemodynamic parameters at different locations of an AVF, and the association between hemodynamic parameters and the anastomotic angle, particularly at the stenotic location. We analyzed 27 patients who used radio-cephalic AVF for hemodialysis and received an angiographic examination for juxta-anastomotic stenosis. The three-dimensional geometrical model of each patient's AVF was built using the angiographic images, in which the shape and the anastomotic angle of the AVF were depicted. CFD simulations of AVF hemodynamics were conducted to obtain blood flow parameters at different locations of an AVF. We found that at the location of the stenotic lesion, the AV angle was significantly correlated with access flow disturbance (r = 0.739; p < 0.001) and flow velocity (r = 0.563; p = 0.002). Furthermore, the receiver operating characteristic (ROC) curve analysis revealed that the AV angle determines the lesion's flow disturbance with a high area under the curve value of 0.878. The ROC analysis also identified a cut-off value of the AV angle as 46.5°, above or below which the access flow disturbance was significantly different. By applying CFD analysis to real-world patient images, the present study provides evidence that an anastomotic angle wider than 46.5° might lead to disturbed flow generation, demonstrating a reference angle to adopt during the anastomosis surgery.

Safety and Efficacy of the Percutaneous Manual Aspiration Thrombectomy Technique to Treat Thrombotic Occlusion of Native Arteriovenous Fistulas for Hemodialysis

목적

대상과 방법

결과

결론

Salvage of thrombosed arteriovenous fistulae of patients on hemodialysis: report on the experience of a Brazilian center

INTRODUCTION

Hemodialysis vascular access thrombosis is an acute event that can interrupt the dialytic treatment. A timely management can restore access patency, avoiding the use of central venous catheters and their complications.

OBJECTIVE

To present the experience from a Brazilian Interventional Nephrology Center (INC) in the salvage of arteriovenous fistula (AVF) and grafts for hemodialysis.

METHODS

A retrospective study was performed to evaluate the primary and secondary patencies of 41 hemodialysis accesses with thrombosis confirmed by ultrasound and submitted to endovascular salvage procedures. We considered clinical success the use of the access for at least 3 subsequent hemodialysis sessions. The procedures were done in an outpatient center by interventional nephrologists. Patients were followed for up to 18 months with Doppler every 3 months.

RESULTS

Forty-five salvage procedures were performed in 41 accesses of 40 hemodialysis patients with native AVF or grafts. Of these, 90% were AVF, mostly upper arm, and 10% were grafts. Clinical success rate was 60% (27 procedures). Primary patency at 12 months was 39% and secondary was 52%. Gender of the patient, diabetes, and location of the access did not correlate statistically with outcomes. There were 3 major complications (anastomosis rupture, grade 3 hematoma, and anaphylactic shock).

CONCLUSION

The majority of thrombosed accesses can be successfully treated, maintaining its long-term patency. The need of repeated intervention is frequent.

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.

Radiological Central Vein Treatment in Vascular Access

In the last decades, the percutaneous interventional approach for the treatment of central venous obstructions (CVO) has become increasingly popular as the treatment of first choice because of its minimal invasiveness and reported success rates. CVOs are caused by a diverse spectrum of diseases which can be broadly categorized into two principal eliciting genera, either benign or malignant obstructions. The large group of benign venous obstructions includes the increasing number of end-stage renal disease patients with vascular access related complications. Due to the invasiveness and complexity of thoracic surgery for benign CVOs, the less invasive percutaneous interventional therapy can generally be considered the preferred treatment option. Initially, the radiological intervention consisted of balloon angioplasty alone, subsequently additional stent placement was applied. This was advocated as either primary placement or secondary in cases of elastic recoil or residual stenosis after percutaneous transluminal angioplasty (PTA). The efficacy of angioplasty of CVO in patients with vascular accesses, either with or without stenting, has been addressed by various studies. Overall, reports indicate an initial technical and clinical success rate above 95% and satisfactory patency rates. However, systematic follow-up and frequent re-interventions are necessary to maintain vascular patency to achieve long-term success.

Predicting Technical Success after Fistuloplasty: An Analysis of 176 Procedures

BACKGROUND

Significant stenoses in arteriovenous fistulae (AVFs) or arteriovenous grafts (AVGs) with limitation of flow and dialysis inadequacy should prompt consideration for fistuloplasty. We sought to identify fistulae, lesions, and patient-specific variables, which predict for outcomes after fistuloplasty.

METHODS

Data were extracted retrospectively from a renal access database from 2011 to 2016 of patients undergoing fistuloplasty. Demographics, comorbidities, outcomes of intervention, and flow rates documented on preintervention and postintervention duplex were collected. Secondary analysis of factors associated with postfistuloplasty flow rates of >600 mL/min, previously shown to be predictive of not requiring future intervention, was performed.

RESULTS

Of 204 attempted fistuloplasties, 176 were completed. One hundred forty (79.5%) were native AVFs and 34 (19.3%), AVGs (no data for 2). Median stenosis treated was 75%, with a majority (43.8%) in the proximal outflow vein. Flow rate on duplex after fistuloplasty was significantly better in AVFs (mean improvement 189.2 mL/min) than that in AVGs (mean improvement 51.8 mL/min; P = 0.034). Greatest flow improvement occurred for needling site stenotic lesions compared with other locations (from anastomosis to central vein) but was not significant. Brachio-brachial or brachio-axillary AVGs did significantly (P < 0.05) worse than all other fistulae types. The presence of hypertension was predicted for postfistuloplasty flow rate of >600 mL/min.

CONCLUSIONS

Flow rates after fistuloplasty vary depending on the type of fistula treated and the presence of hypertension. Knowledge of this can lead to better patient selection and counseling for fistuloplasty.

Definitions and End Points for Interventional Studies for Arteriovenous Dialysis Access

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

Vascular Access Practice Patterns in Canada: A National Survey

Background:

One of the mandates of the Canadian Society of Nephrology’s (CSN) Vascular Access Working Group (VAWG) is to inform the nephrology community of the current status of vascular access (VA) practice within Canada. To better understand VA practice patterns across Canada, the CSN VAWG conducted a national survey.

Objectives:

(1) To inform on VA practice patterns, including fistula creation and maintenance, within Canada. (2) To determine the degree of consensus among Canadian clinicians regarding patient suitability for fistula creation and to assess barriers to and facilitators of fistula creation in Canada.

Design:

Development and implementation of a survey.

Setting:

Community and academic VA programs.

Participants:

Nephrologists, surgeons, and nurses who are involved in VA programs across Canada.

Measurements:

Practice patterns regarding access creation and maintenance, including indications and contraindications to fistula creation, as well as program-wide facilitators of and barriers to VA.

Methods:

A small group of CSN VAWG members determined the scope and created several VA questions which were then reviewed by 5 additional VAWG members (4 nephrologists and 1 VA nurse) to ensure that questions were clear and relevant. The survey was then tested by the remaining members of the VAWG and refinements were made. The final survey version was submitted electronically to relevant clinicians (nephrologists, surgeons, and nurses) involved or interested in VA across Canada. Questions centered around 4 major themes: (1) Practice patterns regarding access creation (preoperative assessment and maturation assessment), (2) Practice patterns regarding access maintenance (surveillance and salvage), (3) Indications and contraindications for arteriovenous (AV) access creation, and (4) Facilitators of and barriers to fistula creation and utilization.

Results:

Eighty-two percent (84 of 102) of invited participants completed the survey; the majority were nurses or VA coordinators (55%) with the remainder consisting of nephrologists (21%) and surgeons (20%). Variation in practice was noted in utility of preoperative Doppler ultrasound, interventions to assist nonmaturing fistulas, and procedures to salvage failing or thrombosed AV-access. Little consensus was seen regarding potential contraindications to AV-access creation (with the exception of limited life expectancy and poor vasculature on preoperative imaging, which had high agreement). Frequent barriers to fistula utilization were primary failure (77% of respondents) and long maturation times (73%). Respondents from centers with low fistula prevalence also cited long surgical wait times as an important barrier to fistula creation, whereas those from centers with high fistula prevalence cited access to multidisciplinary teams and interventional radiology as keys to successful fistula creation and utilization.

Conclusions:

There is significant variation in VA practice across Canada and little consensus among Canadian clinicians regarding contraindications to fistula creation. Further high-quality studies are needed with regard to appropriate fistula placement to help guide clinical practice.

Restoration of Acutely Thrombosed Arterio-Venous Fistulae by rTPA and Percutaneous Angioplasty

Acute thrombosis in native arterio-venous fistulae (AVF) results in considerable patient morbidity. Interventional radiology (IR) comprising thrombolysis and percutaneous transluminal angioplasty (PTA) is well established in the management of thrombosed polytetrafluoroethylene (PTFE) grafts. However its role in thrombosed AVF is uncertain. We looked retrospectively at the role of IR in re-establishing blood flow in acutely thrombosed AVF.

Between 1992–2000, 21 episodes of acutely thrombosed AVF in 15 patients (9 females; age range 29–80yrs) were referred for intervention. All fistulae were being used for haemodialysis at the time. Diagnosis was established by angiography and thrombolysis with recombinant tissue plasminogen activator (rTPA) was attempted in all patients. Discrete stenoses when present (n=12) were then treated with PTA and resistant or recurrent stenoses were managed by stent insertion (n=3). Patients were then heparinised for 24 hours.

Technical success as defined by radiological patency was achieved in 86% cases. Clinical success i.e. the ability to reuse of the fistula for haemodialysis was achieved in 62% of the interventions, where patency rates at 3 and 6 months were 92% and 69% respectively. Five patients had recurrence of thrombosis >3 months after the primary procedure, 3 had successful re-intervention. Minor local bleeding was the only complication.

Our retrospective study shows rTPA and PTA is successful in the management of acutely thrombosed AVF. We advocate the routine use of IR as a valuable technique for prolonging the life of native AVF in patients on maintenance haemodialysis.

A new technique for autogenous brachiobasilic upper arm transposition for vascular access for hemodialysis

Purpose

Conventional brachiobasilic fistula creation consists of the mobilization and preparation of the brachial part of the basilic vein along its whole length, the vein transposition on the anterior surface of the arm and anastomosis using the brachial artery. In case of late thrombosis, the reparation of such a fistula is almost impossible.

Methods

To avoid total vein clotting in the case of thrombosis we decided to prepare only a short part of the vein in our method and not to mobilize the other part of the vein. The brachiobasilic fistula with our modification was performed as a two-stage procedure in 18 patients (8 females and 10 males), aged from 37–78 yrs (60 ± 13.6 yrs).

Results

In two patients early thrombosis occurred. The reparation procedure was not performed in two patients (the first patient died due to pneumonia; the second patient did not give his permission for further intervention). In 16 patients brachiobasilic fistula creation was successful. Late thrombotic complications occurred in three patients (in the 3rd, 8th and 12th months). A new successful fistula, a few centimeters proximally to the original one, was performed in 2 patients 24hr and in 1 patient 48hr after fistula clotting. On the following day after the procedure the fistula was ready to be used. The primary, assisted primary and cumulative secondary patency rates after 12 months of follow-up were 74, 89 and 100%, respectively.

Conclusion

In comparison with standard brachiobasilic techniques our method offers the possibility of a reparation procedure in the case of late thrombosis, which could improve the long-term patency of brachiobasilic fistulas. However, a prospective controlled study is necessary to establish if this new technique is superior to the traditional surgical procedure.

Percutaneous treatment of thrombosed arteriovenous fistulae using the Gelbfish-Endovac aspiration thrombectomy device

Purpose

To study the efficacy and safety of percutaneous treatment of thrombosed hemodialysis arteriovenous fistulae (AVF) using the Gelbfish-Endovac aspiration thrombectomy device (Gelbfish-Endovac).

Methods

From September 2003 to May 2004, twenty-nine percutaneous thrombectomy procedures were performed in 27 patients (median age of 67 years, 14 females) with thrombosed hemodialysis AVF using the Gelbfish-Endovac. Prior interventions, procedure time, anticoagulation, use of additional devices/thrombolytic agents, technical success, clinical success, complication rates, and patency at 30, 60 and 90 days were evaluated.

Results

Sixteen upper arm and 13 forearm AVF were declotted. Seventeen AVF had prior percutaneous interventions. Three AVF had not matured. Median AVF age was 9 months. Heparin was used in 14 procedures. Sixteen arterial lesions and 25 venous lesions were uncovered and treated. Two AVF required the additional use of the Arrow-Trerotola percutaneous thrombectomy device. One AVF underwent side branch ligation. No thrombolytic agents were used. Median procedure time was 70 minutes. Initial technical success was achieved in 24 AVF and clinical success was achieved in 22 AVF. Eleven complications occurred. Ten AVF remained open at 30 days, 10 at 60 days and 8 at 90 days without further interventions. With additional percutaneous interventions, 16 AVF remained open at 30 days, 16 at 60 days and 15 at 90 days.

Conclusion

The Gelbfish-Endovac aspiration thrombectomy device is safe and efficacious for percutaneous de-clotting of AVF.

Surgery versus Interventional Radiology in the Management of Thrombosed Vascular Access for Hemodialysis

Thrombosis is the most frequent complication occurring in vascular access (VA). The two widely used treatment strategies for thrombosed VA are surgical and endovascular. Which is the best and whether different approaches should be used on proximal versus distal VA, is still debated. This is a retrospective study. Over a three years period, we studied among a population of 475 dialysis patients, 54 VA thromboses in 46 patients. Surgical procedure was successful in 14/17 (82%) distal artero-venous fistulas (AVF) while, in 9 proximal AVF, it led to initial success in 6 patients (66%), with a six months primary patency respectively of 93% and 84%. Radiological procedure resolved 6/10 distal AVF (initial success 60%) with primary patency of 66%, and was successful in 16/18 proximal AVF (initial success 89%) with primary patency of 81%. Taking our data all together, no differences are found between two thrombolitic (surgical and endovascular) procedures. But results were different in thrombosed proximal VA (where endovascular treatment should be preferred) versus distal ones (where surgery seems better).

Stent tunnel technique to save thrombosed native hemodialysis fistula with extensive venous aneurysm

INTRODUCTION AND PURPOSE

The increasing number of patients undergoing hemodialysis and the limited number of access sites have resulted in an increasing number of techniques to maintain vascular access for hemodialysis. Thrombosed arteriovenous (AV) fistulas with large venous aneurysms have poor treatment results, with both endovascular and surgical techniques, leading to a high rate of definitive AV access loss. The purpose of this study was to review the feasibility and initial results of this novel endovascular treatment of thrombosed AV fistulas with large venous aneurysms.

MATERIALS AND METHODS

A novel endovascular treatment technique of inserting nitinol auto-expandable uncovered stents stretching through the whole puncture site area, thus creating a tunnel inside the thrombus, was retrospectively analyzed and described.

RESULTS

A total of 17 stents were placed in 10 hemodialysis fistulas, with a mean venous coverage length of 17.8 cm. In all the cases, 100% technical success was achieved, with complete restoration of blood flow in all patients. There were no procedure-related complications. The mean follow-up was 167 days (range 60-420 days), with a primary and assisted patency of 80% and 100%, respectively. No multiple trans-stent struts-related complications were observed. Three stent fractures were diagnosed with plain films at the site of puncture without consequence in the venous access permeability.

CONCLUSION

The "stent tunnel technique" is a feasible, safe and effective alternative to salvage native hemodialysis access, thus extending the function of the venous access with no signs of stent-related complications and a respectable midterm patency.

Exercise effectiveness of arteriovenous fistula maturation in chronic renal patients: A systematic review with meta-analysis

Aims:

The purpose of this research is to evaluate the effectiveness of upper limb exercises to improve arteriovenous fistula maturation in patients with chronic kidney disease.

Methods:

A bibliographic search was carried out from February to August 2015 in the following databases: PUBMED, CINAHL, Web of Science, SCOPUS, LILACS, SCIELO and CENTRAL.

Results:

Three studies were included, involving 134 participants (total). According to the total effect estimation, a mean difference of 0.36 (-0.95–1.67) was found for vein diameter, meanwhile a mean difference of 107.87 (-3.90–219.64) was found for blood flow.

Conclusion:

It was not possible to determine the effect size of the treatment due to a high bias risk of all included studies. Given this, the available evidence is still insufficient to support the prescription of upper limb exercises in order to improve arteriovenous fistula maturation. Therefore, randomised and controlled clinical trials monitored by methodological rigour should be developed in order to verify if the AVF maturation process can be evidenced through exercise.

Use of a proactive duplex ultrasound protocol for hemodialysis access

OBJECTIVE

Arteriovenous fistula (AVF) creation is the preferred approach for hemodialysis access; however, the maturation of AVFs is known to be poor. We established a proactive early duplex ultrasound (DUS) surveillance protocol for evaluating AVFs before attempted access. This study determined the effect of this protocol related to improving AVF maturation.

METHODS

From 2008 to 2013, 153 patients received new upper extremity AVFs and an early DUS surveillance protocol at a single academic institution. The protocol involved an early DUS evaluation before hemodialysis cannulation of the AVF at 4 to 8 weeks after AVF creation. A positive DUS result was identified as a peak systolic velocity of >375 cm/s or a >50% stenosis on gray scale imaging, along with decreased velocity in the outflow vein. Patients with positive DUS findings underwent prophylactic endovascular or open intervention to assist with AVF maturation. Nature of secondary interventions, as well as AVF patency and maturation, were assessed. Overall clinical outcomes and fistula patency were investigated.

RESULTS

During the study period, 183 upper extremity AVFs were created in 153 patients, including 82 radiocephalic, 63 brachiocephalic, and 38 brachiobasilic AVFs. A mortality rate of 43% (n = 66) was observed in a median follow-up period of 34.5 months (interquartile range, 19.6-46.9). A total of 164 early DUS were performed at a median of 6 weeks (interquartile range, 3.4-9.6 weeks) after the initial creation. Early DUS showed nine AVFs were occluded and were excluded from further analysis. Hemodynamically significant lesions were found in 62 AVFs (40%); however, only 17 (11%) were associated with an abnormal physical examination. Positive DUS finding prompted a secondary intervention in 81% of the patients. Among those with positive early DUS findings, AVF maturation was 70% in those undergoing a secondary intervention compared with 25% in those not undergoing a prophylactic intervention (P = .011). Primary-assisted patency for AVFs with early positive and negative DUS findings were 83% and 96% at 6 months, 64% and 89% at 1 year, and 52% and 82% at 2 years, respectively (P < .001).

CONCLUSIONS

Early DUS surveillance of AVFs before initial access is reasonable to identify problematic AVFs that may not be reliably detected on clinical examination. Although DUS criteria for AVFs have yet to be universally accepted, proactive early postoperative DUS interrogation assists in the early detection of dysfunctional AVFs and improvement of fistula maturation. Despite improved patency in those with positive DUS findings who undergo prophylactic secondary intervention, overall patency remains inferior to those without an abnormality detected on early DUS imaging.

Soluble adhesion molecules as markers of native arteriovenous fistula thrombosis in children on uremia

Vascular access represents a lifeline for children undergoing hemodialysis. A failure of vascular access among patients receiving regular hemodialysis is associated with increased morbidity, mortality and costs. We assessed the possibility of using soluble adhesion molecules as reliable predictors of vascular access failure in children on hemodialysis. Moreover, we evaluated whether there is an association among the different studied adhesion molecules in hemodialysis patients with thrombosed and non-thrombosed arteriovenous fistula fistulas (AVFs). This study included 55 hemodialysis children, 36 with good access and 19 with access failure, and 20 healthy volunteers. Forty-four patients had native AVFs and 11 patients had tunneled permanent catheter (11with thrombosed and 33 with non-thrombosed AVFs). Serum-soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble E-selectin (sE-selectin) and soluble P-selectin (sP-selectin) were measured using ELISA technique. A significant increase was found in the levels of sVCAM-1, sICAM-1, sE-selectin and sP-selectin versus controls and all hemodialysis patients, hemodialysis patients with good access and hemodialysis patients with access failure (P=0.001 for sVCAM-1 and sICAM-1 and P=0.0001 for sE-selectin and sP-selectin). A significant increase was found in the levels of sVCAM-1, sE-selectin and sP-selectin in both chronic hemodialysis patients with thrombosed and non-thrombosed native AVFs versus controls (P=0.0001 for all parameters). There was significant difference between both chronic hemodialysis patients with thrombosed and non-thrombosed native AVFs as regard to sVCAM-1 (54.64±30.82 versus 25.69±27.96ng/ml, P=0.04). Both sICAM-1 and sP-selectin were positively correlated with the erythropoietin (EPO) dose in hemodialysis children (r=0.31, P=0.04 and r=0.32, P=0.04, respectively). A significant positive association was found between E-selectin and sP-selectin in hemodialysis patients with thrombosed AVFs (r=0.83, P=0.04). There was a significant correlation between sVCAM-1 and EPO dose in thrombosed AVF group (r=0.84, P=0.01). The assessment of serum sVCAM-1 might be useful for the identification of the chronic hemodialysis patients at an increased risk for native AVFs thrombosis. The role of EPO in vascular access failure should be taken into consideration. The clinical relevance of these observations warrants further investigations.

Percutaneous Rheolytic Thrombectomy of Thrombosed Autogenous Dialysis Fistulas

Purpose: To retrospectively analyze the technical and clinical outcome of percutaneous rheolytic thrombectomy with the use of the AngioJet device in thrombosed autogenous arteriovenous dialysis fistulas. Methods: A cohort of 38 consecutive patients (24 men; mean age 70.7±13.8 years) presenting with 59 thrombotic events in 39 autogenous dialysis fistulas were retrospectively analyzed. The AngioJet rheolytic thrombectomy device was used in all cases. Adjunctive therapies, as well as procedure-related complications, were noted. Primary, assisted primary, and secondary patency of the autogenous fistulas was assessed along with factors potentially influencing patency. Results: Initial technical success to recanalize the efferent vein was 100% (n=59), and a successful postprocedure dialysis session was possible in 97% (n=57) of cases. Adjunctive procedures included percutaneous thromboaspiration (n=4, 7%), balloon angioplasty (n=59, 100%), and stent placement (n=16, 27%). Complications related to thrombectomy occurred in 3 (5%) procedures (distal arterial embolus). Primary, assisted primary, and secondary patency rates at 12 months were 56.1% (95% CI 42.8% to 75.2%), 61.6% (95% CI 48.6% to 74.7%), and 86.2% (95% CI 74.9% to 97.5%), respectively. Risk factors for early fistula occlusion were greater patient age (p=0.045), the age of the fistula (p=0.045), previous stent insertion (p=0.019), and an upper arm fistula (p=0.047). Conclusion: Percutaneous rheolytic thrombectomy of autogenous dialysis fistulas is effective in restoring patency and allowing subsequent hemodialysis. The complication rate is acceptably low, and the large majority of the fistulas are still used for hemodialysis at 1-year follow-up. Older fistulas and upper arm fistulas are at higher risk for early rethrombosis.

Pharmacomechanical thrombolysis for the treatment of thrombosed native arteriovenous fistula: a single-center experience

Background

Native arteriovenous fistula is one of the important routes for hemodialysis patients because of increased long-term survival and preservation of quality of life. We reported on a single-center experience with using pharmacomechanical thrombolysis for the treatment of thrombosed native arteriovenous fistula.

Material/Methods

This was a retrospective study of 12 hemodialysis patients (8 males and 4 females) with 14 thrombosed distal forearm Brescia-Cimino radiocephalic fistulas who were referred for pharmacomechanical thrombolytic treatment in the intervention unit of the Radiology Department, from 1 January 2010 to 30 December 2011. Demographic data, technical success rates, clinical success rates and complications were evaluated. The patency was evaluated by Kaplan-Meier analysis.

Results

The technical and clinical success was found in 12 thrombosed fistulas. Only 3 procedures had minor complications including small amounts of adjacent soft tissue hematoma. There were no procedure-related major complications. The primary patency rates at 6 and 12 months were 67% and 50%. The secondary patency rates at 6 and 12 months were 75% and 67%.

Conclusions

Pharmacomechanical thrombolysis is a minimally invasive, effective, durable, and safe procedure for the treatment of thrombosed native arteriovenous fistula. This procedure can be considered as an alternative treatment for thrombosed dialysis fistulas.

Central Transposition of the Cephalic Vein in Patients with Brachiocephalic Arteriovenous Fistula and Cephalic Arch Stenosis

Purpose:

Our study aims to evaluate to evaluate clinical outcomes after cephalic vein transposition (CVT) to the axilla in patients with brachiocephalic arteriovenous fistula (BC-AVF) and cephalic arch stenosis (CAS).

Materials and Methods:

Hospital records of 13 patients (median age, 61 years; males, 54%) who received CVT to the proximal basilic/axillary vein due to either dysfunction (n=2) or thrombosis (n=11) between January 2010 and February 2014 were retrospectively reviewed.

Results:

Operation was performed under local anesthesia in all cases. There was no technical failure. Concomitant inflow procedure (banding or aneurysmorrhaphy) was performed in 5 patients (38%). During follow-up (1 to 50 months, median 17 months), 3 patients died with functioning AVF and one was successfully transplanted. Two patients suffered from recurrent symptomatic stenosis of AVF and received percutaneous balloon angioplasty. Another 2 patients experienced AVF occlusion treated with interposition graft and manual fragmentation. Overall primary, assisted primary, and secondary patency rates were 77.5%, 92.3%, and 100% at 6 months and 66.1%, 92.3%, and 100% at 1 year, respectively.

Conclusion:

Although most patients presented with BC-AVF occlusion, technical success and access patency rates after CVT were favorable compared with historical data for interventional treatment. CVT should be considered as an appropriate option in selected patients with CAS.

Ipsilateral jugular access to treat an otherwise inaccessible puncture-related arteriovenous fistula pseudoaneurysm: a technical note

BACKGROUND

The standard approach for the endovascular treatment of a dysfunctional or occluded hemodialysis access in the upper limbs includes a direct intervention through the access itself or alternatively, when not feasible, through the brachial or radial artery access. Nonetheless, there are certain circumstances in which these approaches are not easily achieved.

METHODS

An 89-year-old male with end-stage renal disease developed a pseudoaneurysm after an hemorrhagic complication of a recently transposed native basilic arteriovenous fistula secondary to a needle puncture. Dehiscence of the injured access with spontaneous arterial bleeding evolved as a consequence of the upper limb swelling, rendering therapeutic intervention of the access through a conventional route impossible. A fistulogram through puncture of the common femoral artery was performed to obtain an accurate diagnosis. However, this approach was insufficient to advance the covered stent with the intention of excluding the pseudoaneurysm, as the stent delivery system could not reach the desired site. Given that the covered stent insertion required a 9 Fr introducer, the radial artery approach was ruled out. Therefore, we chose a venous access via the ipsilateral internal jugular vein, which was punctured under ultrasound guidance.

RESULTS

This strategy was useful to advance the stent and exclude the pseudoaneurysm successfully.

CONCLUSIONS

This technique should be considered for those individuals in whom conventional routes of approach for repairing dialysis accesses are not feasible or are extremely risky.

Endovascular stent placement of juxtaanastomotic stenosis in native arteriovenous fistula after unsuccessful balloon angioplasty

Background

In hemodialysis patients, the most common problem in arteriovenous fistulas, as the best functional vascular access, is the juxtaanastomotic located lesions. Percutaneous transluminal angioplasty is accepted as the treatment method for juxtanastomotic lesions.

Objectives

To assess juxtaanastomotic stent placement after insufficient balloon angioplasty in the treatment of autogenous radiocephalic or brachiocephalic fistula dysfunction.

Patients and Methods

Between July 2003 and June 2010, 20 hemodialysis patients with autogenous radiocephalic or brachiocephalic fistula dysfunction underwent stent placement for the lesion located at the juxtaanastomotic region. Indications for stent placement were insufficient balloon dilatation, early recurring stenosis, chronic organizing thrombus and vessel rupture. The Kaplan-Meier method was used to calculate the stent patency rates. All patients who had fistula dysfunction (thrombosis of hemodialysis access, difficult access cannulation, extremity pain due to thrombosis or decreased arterial access blood flow) were evaluated by color Doppler ultrasound. The stenoses were initially dilated with standard noncompliant balloons (3 to 10-mm in diameter). Dilatation was followed by high pressure (Blue Max, Boston Scientific) or cutting balloons (Boston Scientific), if the standard balloon failed to dilate the stenotic segment.

Results

Twenty-one stents were applied. The anatomical and clinical success rate was 100%. Seventeen additional interventions were done for 11 (55%) patients due to stent thrombosis or stenosis during follow-up. Our 1- and 2-year secondary patency rates were 76.2% and 65.5%, respectively and were comparable to those after balloon angioplasty and surgical shunt revision.

Conclusion

Metallic stent placement is a safe and effective procedure for salvage of native hemodialysis fistula after unsuccessful balloon angioplasty.

Challenges and management of high-flow arteriovenous fistulae

The Kidney Dialysis Outcomes Quality Initiative and Fistula First Initiative have embraced the arteriovenous fistula as the gold standard for hemodialysis accesses. Despite this status, fistulae are fraught with complex issues ranging from a high primary failure rate to high flow resulting in increased cardiovascular morbidity. It is important not to overlook the insidious peril of a hyperfunctioning access that may actively promote cardiac overload, cardiopulmonary recirculation, rapid access growth with aneurysm enlargement, recurrent venous stenosis resulting in access failure, and inflow/outflow mismatch. Once recognized, flow can and should be reduced to mitigate these and other negative effects.

Objective and subjective assessment of physician labor and resource utilization in maintenance percutaneous transluminal angioplasty of nonthrombosed hemodialysis arteriovenous fistulas versus arteriovenous grafts

PURPOSE

To complement prior studies that have shown that arteriovenous fistula (AVF) thrombectomies require more time and equipment than arteriovenous graft (AVG) thrombectomies by measuring work via established instruments to determine whether there is also a difference in maintenance percutaneous transluminal angioplasty (PTA) of nonthrombosed AVFs versus AVGs.

MATERIALS AND METHODS

PTA procedures performed on a consecutive cohort of 42 patients with AVFs and 27 patients with AVGs were prospectively compared. To quantify resource utilization, procedure time and disposable equipment were measured. Established instruments developed by the American Medical Association for Current Procedural Terminology code valuation were used to measure subjective "physician work," including mental effort and judgment, technical skill, physical effort, and psychological stress. These items were scored by 1 of 12 attending interventional radiology physicians performing the procedure.

RESULTS

Mean PTA procedure time was 74 minutes (range, 18-183 minutes) for AVFs and 71 minutes (range, 28-204 minutes) for AVGs; hemostasis time was 12 minutes for AVFs and 11 minutes for AVGs. There was no significant difference in equipment use between groups. "Physician work" for AVFs scored significantly higher in four categories (P≤ .05).

CONCLUSIONS

Using established subjective instruments, maintenance PTA of AVFs was scored as more cognitively, physically, and psychologically demanding than maintenance PTA of AVGs. However, there was no significant difference in resource utilization between maintenance PTA of AVFs versus AVGs, as has been previously shown with thrombectomy of thrombosed AVFs and AVGs.

Effect of buttonhole cannulation with a polycarbonate PEG on in-center hemodialysis fistula outcomes: a randomized controlled trial

BACKGROUND

Quality improvement strategies to increase and maintain the numbers of arteriovenous fistulas (AVFs) are a critical drive in enhancing the quality of care of patients receiving treatment with hemodialysis. How the AVF is needled is an important consideration in AVF survival; the ideal cannulation technique has not been established to date.

STUDY DESIGN

Prospective randomized single-center trial.

SETTING & PARTICIPANTS

Patients on maintenance hemodialysis therapy (N = 140).

INTERVENTION

A 1-year intervention of buttonhole (constant site) or usual-practice (different site) cannulation.

OUTCOMES

Primary study outcome was AVF survival over 1 year, in which AVF failure was defined as an AVF no longer used for hemodialysis (also referred to as assisted patency). Secondary outcomes included primary patency, number of access interventions, bleeding time, infection rate, cannulation time and pain, and aneurysm formation.

RESULTS

Demographic data were similar for both groups. The primary outcome measure of AVF survival at 1 year was statistically significantly increased in the buttonhole group (100% vs 86% with usual practice; P = 0.005, log-rank test). In the buttonhole group, there were fewer interventions (19% vs 39% in usual practice) and less existing aneurysm enlargement (23% vs 67% in usual practice). There were no bacteremia events in the buttonhole group and 2 in the usual-practice group (0.09/1,000 AVF days). There were no significant differences in bleeding times and lignocaine use between the 2 groups.

LIMITATIONS

A single-center study, lack of blinding.

CONCLUSIONS

In this study, AVF survival was significantly greater when using buttonhole cannulation. The buttonhole technique significantly decreased the need for access interventions and reduced existing aneurysm enlargement. Concerns of increased infection rates or prolonged bleeding times with the buttonhole technique were not seen in this study. The buttonhole technique should be considered the cannulation technique of choice for AVFs.

Treatment of hemodialysis vascular access rupture irresponsive to prolonged balloon tamponade: retrospective evaluation of the effectiveness of N-butyl cyanoacrylate seal-off technique

OBJECTIVE

The current study retrospectively evaluated whether the percutaneous N-butyl cyanoacrylate (NBCA) seal-off technique is an effective treatment for controlling the angioplasty-related ruptures, which are irresponsive to prolonged balloon tamponade, during interventions for failed or failing hemodialysis vascular accesses.

MATERIALS AND METHODS

We reviewed 1588 interventions performed during a 2-year period for dysfunction and/or failed hemodialysis vascular access sites in 1569 patients. For the angioplasty-related ruptures, which could not be controlled with repeated prolonged balloon tamponade, the rupture sites were sealed off with an injection of a glue mixture (NBCA and lipiodol), via a needle/needle sheath to the rupture site, under a sonographic guidance. Technical success rate, complications and clinical success rate were reported. The post-seal-off primary and secondary functional patency rates were calculated by a survival analysis with the Kaplan-Meier method.

RESULTS

Twenty ruptures irresponsive to prolonged balloon tamponade occurred in 1588 interventions (1.3%). Two technical failures were noted; one was salvaged with a bailout stent-graft insertion and the other was lost after access embolization. Eighteen accesses (90.0%) were salvaged with the seal-off technique; of them, 16 ruptures were completely sealed off, and two lesions were controlled as acute pseudoaneurysms. Acute pseudoaneurysms were corrected with stentgraft insertion in one patient, and access ligation in the other. The most significant complication during the follow-up was delayed pseudoaneurysm, which occurred in 43.8% (7 of 16) of the completely sealed off accesses. Delayed pseudoaneurysms were treated with surgical revision (n = 2), access ligation (n = 2) and observation (n = 3). During the follow-up, despite the presence of pseudoaneurysms (acute = 1, delayed = 7), a high clinical success rate of 94.4% (17 of 18) was achieved, and they were utilized for hemodialysis at the mean of 411.0 days. The post-seal-off primary patency vs. secondary patency at 90, 180 and 360 days were 66.7 ± 11.1% vs. 94.4 ± 5.4%; 33.3 ± 11.1% vs. 83.3 ± 8.8%; and 13.3 ± 8.5% vs. 63.3 ± 12.1%, respectively.

CONCLUSION

Our results suggest that the NBCA seal-off technique is effective for immediate control of a venous rupture irresponsive to prolonged balloon tamponade, during interventions for hemodialysis accesses. Both high technical and clinical success rates can be achieved. However, the treatment is not durable, and about 40% of the completely sealed off accesses are associated with developed delayed pseudoaneurysms in a 2-month of follow-up. Further repair of the vascular tear site, with surgery or stent-graft insertion, is often necessary.

Cardiac Arrest Secondary to Bilateral Pulmonary Emboli following Arteriovenous Fistula Thrombectomy: A Case Report with Review of the Literature

Number of patients with End Stage Renal Disease (ESRD) is growing worldwide. Hemodialysis remains the main modality of renal replacement therapy for ESRD patients. A patent hemodialysis access (arteriovenous fistula or arteriovenous graft) plays a key role in successful delivery of hemodialysis. Common vascular access issues encountered by patients and nephrologists are thrombosis and infection. The thrombosed access is declotted by various percutaneous techniques these days by multiple outpatient access centers in a timely fashion. Thrombolysis can give rise to various complications, a few of which can be life threatening. A young hemodialysis patient underwent percutaneous thrombolysis of his clotted arteriovenous fistula. Outpatient access thrombectomy was complicated immediately afterwards with cardiac arrest requiring cardiac resuscitation in the recovery room. The patient was admitted to intensive care unit after life sustaining care. Work up revealed multiple pulmonary emboli to both lung fields on CT scan of the chest. Patient was anticoagulated and discharged from the hospital. Thrombolysis of clotted hemodialysis access is associated commonly with occurrences of pulmonary embolic which are usually asymptomatic. Massive pulmonary embolization due to access thrombolysis is rare. Nephrologists and radiologists should be aware of this dangerous complication particularly in patients with preexisting cardiopulmonary disease.

Allogenous vein graft as vascular access for hemodialysis--lost battle?

PURPOSE

The purpose of this paper is to assess a long-term outcome of allogenous vein grafts (ALVG) as vascular access for hemodialysis.

MATERIALS AND METHODS

For nearly eight years (between 9/2002 and 9/2011) a total of 78 patients with 112 ALVGs were involved in the study. The register included 46 women and 32 men, mean age 66.1 ± 11.2 years; range 20-88 years. The patient database was retrospectively reviewed and statistical processing was performed.

RESULTS

Almost all ALVGs were treated by PTA or surgically, very often repeatedly. The number of radiologic interventions was 316, the number of surgical procedures 31. Mean follow-up time was 795 days, range 28-3522 days. Thirty-five patients died of unrelated causes, nineteen with functional graft, fourteen patients were lost to follow-up. Forty ALVGs failed for various reasons, mostly because of occlusion. Only one patient underwent successful renal transplantation, no patient converted to peritoneal dialysis. Thirty-seven ALVGs remain correctly functioning. Primary patency rates at 6, 12, and 24 months were 81 ± 5%, 63 ± 5%, and 34 ± 2% respectively. Secondary patency rates at 6, 12, and 24 months were 96 ± 2%, 82 ± 4%, and 65 ± 5% respectively.

CONCLUSIONS

Allogenous vein grafts, in spite of the high number of necessary radiologic and surgical interventions and reinterventions, show acceptable clinical usability and durability, comparable with other types of prosthetic grafts.