Results of repeated percutaneous interventions on failing arteriovenous fistulas and grafts and factors affecting outcomes

Efficacy of drug-coated balloon versus uncoated balloon for dysfunctional dialysis access: a systematic review and meta-analysis

BACKGROUND

Dysfunctional vascular access is a major cause of morbidity and mortality in patients undergoing hemodialysis, affecting both arteriovenous fistulas and grafts. The most optimal strategy to restore long-term patency has not been established. This meta-analysis compares drug-coated balloon (DCB) versus uncoated balloon (UCB) angioplasty for dysfunctional vascular access.

METHODS

We performed a systematic literature search across multiple databases from inception to June 2024. Randomized-controlled trials (RCTs) comparing DCB and UCB in dialysis patients with dysfunctional vascular access were included. Risk ratios were pooled using a random-effects model.

RESULTS

Twenty-seven RCTs (2645 patients) were included. Target lesion patency (TLP) at 6 months was significantly superior in the DCB group (RR 1.22, 95% CI 1.07-1.39, p = 0.003). The two regimens were comparable for TLP at 3 months (RR 1.14, p = 0.24) and 12 months (RR 1.14, p = 0.10). The two regimens were comparable in terms of circuit patency rate, target-lesion revascularization, and all-cause mortality.

CONCLUSION

DCB has significantly superior TLP and a comparable risk of mortality to UCB. Further research is warranted to identify factors affecting outcomes following DCB angioplasty for dysfunctional dialysis access.

Ultrasound guided percutaneous sharp recanalization for restoring patency from peripheral chronic total occlusions of hemodialysis accesses

OBJECTIVE

Resistant chronic total occlusion (CTO) lesions present an ongoing challenge for conventional endovascular interventions to restore functional hemodialysis (HD) access. This study endeavors to present a novel endovascular approach utilizing ultrasound (USG)-guided percutaneous sharp recanalization to cross the resistant occlusions and evaluates its effectiveness.

METHODS

This is a multi-center retrospective review of consecutive patients received USG guided sharp recanalization for the treatment of resistant CTO lesions of their HD access between 1st January 2019 and 31st July 2023. Data encompassing patient demographics, access and lesion characteristics, procedural specifics, associated complications, immediate clinical outcomes, and outcomes during follow-up were collected. The procedural technical and clinical success, Kaplan-Meier estimated target lesion (TLPP), access circuit primary patency (ACPP), and index access secondary patency (SP) were reported.

RESULTS

During the study period, 22 patients underwent USG-guided sharp recanalization procedures in the three participating centers with median follow-up of 14.5 months. Both the technical and clinical success were 100%. Only two patients experienced minor complications of localized hematoma over the access, with no instances of major complication. Kaplan-Meier estimated TLPP and ACPP at 3-, 6-, and 12 months were 90.9%, 68.2%, 56.8%, and 90.9%, 63.6%, 52.1% respectively. The SP rates were 100%, 95.5%, and 84.1% at 3-, 6-, and 12 months respectively.

CONCLUSION

USG guided percutaneous sharp recanalization is an effective and safe endovascular approach to treat resistant CTO lesions of dysfunctional HD access.

Assessment of Sonographic Parameters for Predicting Primary Patency Rate in Hemodialysis Patients With Venous Valve-Related Stenosis

OBJECTIVES

Ultrasonography is more frequently used in patients with arteriovenous fistula (AVF) stenosis. The aim of this study is to use sonographic parameters for predicting primary patency in hemodialysis patients with venous valve-related stenosis (VVRS) who are treated by ultrasound-guided percutaneous transluminal angioplasty (PTA).

METHODS

A total of 229 VVRS patients who underwent PTA between January 2017 and December 2021 were enrolled. Clinical characteristics were retrospectively collected. Sonographic parameters were measured both before and after PTA. Univariate and multivariate Cox analyses were performed to identify independent factors associated with primary patency rate.

RESULTS

All measured sonographic parameters improved after PTA compared to before PTA. Before PTA, the diameter of VVRS > 1.0 mm, age ≤ 57 years, and body mass index (BMI) > 21.57 kg/m2 were associated with better outcomes. While the diameter of radial artery, proximal radial artery close to the anastomosis, brachial artery, the flow volume of brachial artery, the length and peak velocity (PV) of the VVRS, and the diameter and PV after the VVRS had no association with the primary patency rate. After PTA, only patients with a diameter of VVRS > 4.0 mm had favorable outcome. In addition, patients with a gain of diameter of VVRS > 2.4 mm after PTA had a trend of better outcomes.

CONCLUSIONS

The diameter of VVRS before and after PTA could be served as markers to predict primary patency rate and second patency rate in AVF patients with VVRS. The gain of diameter of VVRS could also be a potential marker.

CLINICAL IMPACT

Using simple markers of sonographic parameters, we could quickly identify patients with a higher risk of restenosis. These patients should be followed more closely in case of restenosis at early. It is also beneficial to the prevention of thrombosis. These measures help to preserve more valuable vascular for a long-term dialysis. Additionally, the physician should pay more attention on the dialysis-related complications in these risky patients, such as hemodialysis-related hypotension.

Comparison of Clinical Effectiveness and Safety of Drug-Coated Balloons versus Percutaneous Transluminal Angioplasty in Arteriovenous Fistulae: A Review of Systematic Reviews and Updated Meta-Analysis

PURPOSE

To evaluate the clinical effectiveness and safety of drug-coated balloons (DCBs) compared with those of percutaneous transluminal angioplasty (PTA) for arteriovenous fistula (AVF) stenosis via a review of systematic reviews (SRs) and an update of the current meta-analysis.

MATERIALS AND METHODS

Literature was searched to retrieve SRs comparing DCBs and PTA for AVFs. A narrative review of SRs and pooled analysis were performed.

RESULTS

Eleven SRs were included. DCBs demonstrated favorable outcomes at 6 and 12 months compared with PTA, with improved patency in 7 SRs and a trend toward favorable outcomes without statistical significance in 3 SRs. Target lesion revascularization (TLR) was reported in 3 SRs; 2 reviews reported a significantly lower incidence in the DCB group than in the PTA group, whereas 1 review reported no significant differences at 12 months. Four studies reporting all-cause mortality revealed no significant difference between the 2 treatments. In the updated meta-analysis including 23 studies, DCBs demonstrated improved primary patency at 6 months (risk ratio [RR], 1.27; 95% CI, 1.07-1.50) and 12 months (RR, 1.36; 95% CI, 1.19-1.55) and were associated with a lower incidence of TLR at 6 months (RR, 0.54; 95% CI, 0.41-0.73) and 12 months (RR, 0.78; 95% CI, 0.62-0.99). There was no difference in mortality between the 2 groups for 24 months.

CONCLUSIONS

A review of SRs and meta-analysis update revealed the consistent benefits of DCBs over PTA in treating AVFs in terms of primary patency and TLR. Compared with PTA, DCBs do not increase mortality risk.

Comparing post-maturation outcomes of arteriovenous grafts and fistulae

BACKGROUND

Though arteriovenous grafts (AVG) mature more reliably than arteriovenous fistulae (AVF) and require fewer maturation procedures (MP) to obtain functional patency, AVG are thought to have worse function after maturation. We explored differences in post-maturation outcomes between the following groups: AVF patients who did (AS-AVF) and did not (unAS-AVF) require assisted maturation and AVG patients who did (AS-AVG) and did not (unAS-AVG) require assisted maturation.

METHODS

Using the US Renal Data System (2012-2017), we retrospectively identified patients who initiated dialysis with a central venous catheter, underwent AVF or AVG placement and achieved successful two-needle cannulation. Primary patency and access abandonment after maturation were compared across groups using competing risks regression methods, generating sub-hazards ratios (sHR).

RESULTS

We identified 42,664 AVF and 12,335 AVG that met inclusion criteria. A larger proportion of AVFs required interventions: 18,408 AVF (43.2%) versus 2594 AVG (21.0%; p < 0.01). Both AS-AVG and AS-AVF patients experienced patency loss at 1 year more frequently compared with unAS-AVG (67.5% & 57.5% vs 55.2% respectively). Patency loss was lowest in unAS-AVF (38.9%). These trends were robust on adjusted analysis (unAS-AVG reference, AS-AVG sHR = 1.44, p < 0.01; AS-AVF sHR = 1.08, p < 0.01, unAS-AVF sHR = 0.67, p < 0.01). AS-AVGs were more likely to be abandoned than unAS-AVGs (11.7% unAS-AVG vs 17.2% AS-AVG). Fistulae, assisted or not, had lower unadjusted rates of 1-year abandonment than grafts (8.9% AS-AVF vs 7.3% unAS-AVF). On adjusted analysis, AVF usage was protective against abandonment (unAS-AVG, reference; AS-AVF sHR = 0.67, p < 0.01; unAS-AVF sHR = 0.59, p < 0.01) while AS-AVG was not (AS-AVG sHR = 1.32, p < 0.01).

CONCLUSIONS

unAS-AVF have the best long-term outcomes. AS-AVF lose primary patency at a higher rate than unAS-AVG. AVGs may be a better choice than AVFs if veins are marginal and likely to require assisted maturation. Further research is needed to identify anatomic and physiologic factors that affect long-term performance and influence conduit choice.

Comparison of percutaneous transluminal angioplasty and surgical revision after intraoperative dilatation with biliary tract probes for arteriovenous fistula stenosis at juxta-anastomosis

BACKGROUND

Percutaneous transluminal angioplasty (PTA) is widely used for stenosis of vascular access (VA) for hemodialysis. We aimed to evaluate the effectiveness of both PTA and surgical revision after intraoperative dilatation with biliary tract probes for juxta-anastomotic stenosis in autogenous radiocephalic arteriovenous fistulas (RCAVFs).

METHODS

We performed a retrospective analysis of PTA and surgical revision after intraoperative dilatation with biliary tract probes; these were the first interventions after RCAVF establishment in 112 patients with juxta-anastomotic stenosis. Anatomical (number of stenoses) and clinical variables (age and gender of the patient, time of hemodialysis, AVF age, presence of diabetes mellitus, and cause of end-stage renal disease) were reviewed. Technical success, clinical success, and post-intervention primary patency were evaluated.

RESULTS

Our study enrolled 35 patients in the PTA group and 77 patients in the surgical revision group. Clinical and technical success rates of both groups were 100%. There were no complications, such as bleeding or hematomas. Using the Kaplan-Meier method, the post-intervention primary patency rates at 3, 6, 9, 12, 18, and 24 months in the PTA group were 100%, 94.28%, 77.1%, 60%, 54.29%, and 45.71%, respectively, and those in the surgical revision group were 100%, 94.81%, 92.2%, 90.91%, 81.82%, and 76.62%, respectively. The post-intervention primary patency rates at 9-24 months in the surgical revision group were significantly higher than those in the PTA group (χ2 = 19.04, p < 0.0001).

CONCLUSION

The post-intervention long-term primary patency rate of surgical revision after intraoperative dilatation with biliary tract probes is higher than that of PTA for the first intervention of patients with juxta-anastomotic stenosis in RCAVFs. The surgical revision method is safe and effective, especially in hospitals that have not yet carried out PTA.

ACR Appropriateness Criteria® Dialysis Fistula Malfunction

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

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

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

Comparing Patency Rates of Arteriovenous Dialysis Access following Percutaneous Thrombectomy Using Various Catheter Directed Therapies

BACKGROUND

Arteriovenous fistulas often require frequent interventions to maintain patency for hemodialysis. Interventions may include open or percutaneous thrombectomy with additional targeted interventions as indicated. We evaluated the primary and cumulative functional patency rates following three unique approaches to percutaneous thrombectomy of thrombosed dialysis access.

METHODS

A retrospective review of 236 unique patients who presented with thrombosed hemodialysis access was analyzed over a period of 4 years from 2016 to 2020. We analyzed a total of 413 procedures that utilized 3 separate percutaneous thrombectomy devices to assist with restoring patency. The Indigo System CAT-D Aspiration Thrombectomy Catheter (Penumbra; Alameda, CA), the Arrow-Trerotola Rotational Thrombectomy System (Teleflex; Wayne, PA) and the Angiojet Rheolytic Thrombectomy Catheter (Boston Scientific, Marlborough, MA) devices were compared for primary and cumulative functional patency. Primary patency was defined as time from percutaneous thrombectomy to next intervention (Angioplasty, stenting, and repeat thrombectomy). Cumulative functional patency was defined as time from percutaneous thrombectomy to time of access abandonment. Medical record chart review was utilized to determine patency rates.

RESULTS

A total of 413 percutaneous thrombectomy procedures were performed. Of the procedures performed, 98 utilized Angiojet, 103 utilized Trerotola, and 212 used Penumbra. The mean primary patency rates in (days) for the devices were as follows: Angiojet (194), Trerotola (204), and Penumbra (107). The mean cumulative functional patency rates (in days) for the devices were as follows: rheolytic thrombectomy (450 days), aspiration thrombectomy (292 days), and rotational thrombectomy (475 days). Angiojet versus Penumbra and Trerotola versus Penumbra both showed diminished patency rates when using the Penumbra catheter that were statistically significant (P < 0.05).

CONCLUSIONS

All percutaneous thrombectomy approaches do not result in the same primary or cumulative functional patency rates. Approaches with Trerotola and Angiojet resulted in improved primary and cumulative functional patency rates compared to those using Penumbra.

Protocol for a qualitative study exploring haemodialysis dependent patients' arteriovenous fistula experience, values and concerns in Sydney, Australia

INTRODUCTION

The experiences of patients from culturally and linguistically diverse backgrounds, with chronic mental illness, disabilities or who identify as sexual or religious minorities are under-represented in clinical research on arteriovenous fistula (AVF) for haemodialysis access. A greater understanding of the experiences, values and concerns of these diverse patient groups are needed to provide haemodialysis access care that addresses the needs of all haemodialysis-dependent patients. This study seeks to describe a broad range of patient experiences related to the creation, care and surveillance of AVFs, including interactions with healthcare teams.

METHODS AND ANALYSIS

This qualitative study will use semistructured interviews with individual patients purposefully selected to provide a diverse patient population. A deliberate strategy will be used to recruit a demographically broad range of participants. Thematic analysis of interview transcripts, using a constant comparative methodology, will generate themes that describe patient experiences, values and concerns. Findings from this study will give a nuanced insight into the experiences of patients on haemodialysis with respect to their AVF.

ETHICS AND DISSEMINATION

Ethical approval for this study was provided by the Sydney Local Health District Human Research Ethics Committee (REGIS identifier: 2021/ETH00362, CH reference number: CH62/6/2021-033). Results will be made available to the participants, local health district, funders and other researchers through various hospital and academic forums. Data will also be published in peer-reviewed journals and be part of a larger body of work looking into patient-reported outcome measures for patients with AVF.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Factors affecting arteriovenous access patency after percutaneous transluminal angioplasty in chronic haemodialysis patients under vascular access monitoring and surveillance: a single-centre observational study

OBJECTIVES

Maintenance of vascular access (VA) patency after percutaneous transluminal angioplasty (PTA) is important and remains a challenge despite VA monitoring and surveillance. The aim of this study was to examine factors affecting the post-PTA arteriovenous access (AVA) patency in patients who have been on close VA monitoring and surveillance for access flow.

DESIGN

Retrospective cohort study.

SETTING

A single medical centre in Taiwan.

PARTICIPANTS

Records of patients who received chronic haemodialysis between 1 January 2017 and 31 December 2018 were retrospectively reviewed. Patients were divided into two groups (without or with PTA intervention on AVA).

PRIMARY AND SECONDARY OUTCOME

Patients were followed until reintervention PTA, termination or abandoned VA or end of study. In addition to routine monitoring, VA flow surveillance was performed every 3 months for detection of VA dysfunction adhering to Kidney Disease Outcomes Quality Initiative guidelines.

RESULTS

A total of 508 patients were selected for study inclusion (with PTA, n=231; without PTA, n=277). At baseline, variables that differed between groups included malignancy and levels of albumin, uric acid, potassium, phosphorous, high-density lipoprotein, total bilirubin and ferritin (all p<0.05). Significant between-group differences were observed for β-adrenergic blocking agents (with PTA, 49.8%; without PTA, 37.5%; p, 0.007) and ADP inhibitors (with PTA, 23.8%; without PTA, 11.2%; p<0.001). Among patients with PTA, those with acute myocardial infarction, high ferritin level or arteriovenous graft (AVG) had a significantly higher risk of reintervention post-PTA (p<0.05). Dipeptidyl peptidase-4 inhibitors, thiazolidinediones, ADP inhibitors, and warfarin use were predictors of post-PTA patency (p<0.05).

CONCLUSIONS

AVG access type, acute myocardial infarction, and high ferritin levels are risk factors for re-intervention post-PTA. These findings may be useful in the development of prophylactic strategies for monitoring VA function and tailoring surveillance programs for these dialysis patients.

Safety and efficacy of arteriovenous fistula angioplasties performed by nephrologists: report from a Brazilian interventional nephrology center

Introduction:

Arteriovenous fistulas (AVF) are the first choice vascular access for hemodialysis. However, they present a high incidence of venous stenosis leading to thrombosis. Although training in interventional nephrology may improve accessibility for treatment of venous stenosis, there is limited data on the safety and efficacy of this approach performed by trained nephrologists in low-income and developing countries.

Methods:

This study presents the retrospective results of AVF angioplasties performed by trained nephrologists in a Brazilian outpatient interventional nephrology center. The primary outcome was technical success rate (completion of the procedure with angioplasty of all stenoses) and secondary outcomes were complication rates and overall AVF patency.

Findings:

Two hundred fifty-six angioplasties were performed in 160 AVF. The technical success rate was 88.77% and the main cause of technical failure was venous occlusion (10%). The incidence of complications was 13.67%, with only one patient needing hospitalization and four accesses lost due to the presence of hematomas and/or thrombosis. Grade 1 hematomas were the most frequent complication (8.2%). The overall patency found was 88.2 and 80.9% at 180 and 360 days after the procedure, respectively.

Conclusion:

Our findings suggest that AVF angioplasty performed by trained nephrologists has acceptable success rates and patency, with a low incidence of major complications as well as a low need for hospitalization.

Editor's Choice - Paclitaxel Coated Balloon Angioplasty vs. Plain Balloon Angioplasty for Haemodialysis Arteriovenous Access Stenosis: A Systematic Review and a Time to Event Meta-Analysis of Randomised Controlled Trials

OBJECTIVE

A systematic review and meta-analysis of randomised controlled trials (RCTs) was performed to determine the effectiveness and safety of drug coated balloon (DCB) angioplasty compared with uncoated plain balloon (PB) angioplasty in treating arteriovenous access stenosis.

METHODS

MEDLINE, Embase, Scopus, and the Cochrane Central Register of Controlled Trials were searched for RCTs comparing paclitaxel coated DCB and PB angioplasty for arteriovenous access stenosis. The last date of the literature search was 31 December 2020. Risk of bias of the retrieved studies was assessed with the Cochrane Collaboration tool for assessing risk of bias (RoB 2.0). The random effects model was used to estimate the risk of loss of target lesion patency (six and 12 months) and circuit patency (six and 12 months). Procedure related adverse events and mortality rate were also compared. Patency results were pooled using the time to event meta-analytical method and the quality of evidence was assessed according to the GRADE approach.

RESULTS

Sixteen eligible trials, including 1 682 lesions, were included in the quantitative analysis for the efficacy and safety of paclitaxel coated DCBs. DCBs were associated with a lower risk of loss of target lesion patency at six months (HR 0.53, 95% CI 0.42 - 0.66) and 12 months (HR 0.60, 95% CI 0.47 - 0.76), and were also associated with improved six and 12 month circuit patency. Overall quality of evidence was moderate to low. Procedural complications were rare, and the risk of death up to 12 months was similar between the two groups (OR 1.03, 95% CI 0.68 - 1.56).

CONCLUSION

Paclitaxel coated DCBs reduced the risk of loss of target lesion patency and circuit patency in arteriovenous access stenosis compared with PBs. Considering the heterogeneity of the included trials, there is a need to investigate optimal treatment regimens regarding drug dose and agent of the DCB and the treatment procedure.

Intimal Hyperplasia and Arteriovenous Fistula Failure: Looking Beyond Size Differences

The development of venous intimal hyperplasia (IH) has been historically associated with failure of arteriovenous fistulas (AVF) used for hemodialysis. This long-standing assumption, based on histological observations, has been recently challenged by clinical studies indicating that the size of the intima by itself is not enough to explain stenosis or AVF maturation failure. Irrespective of this lack of association, IH is present in most native veins and fistulas, is prominent in many cases, and suggests a role in the vein that may not be reflected by its dimensions. Therefore, the contribution of IH to AVF dysfunction remains controversial. Using only clinical data and avoiding extrapolations from animal models, we critically discuss the biological significance of IH in vein remodeling, vascular access function, and the response of the venous wall to repeated trauma in hemodialysis patients. We address questions and pose new ones such as: What are the factors that contribute to IH in pre-access veins and AVFs? Do cellular phenotypes and composition of the intima influence AVF function? Are there protective roles of the venous intima? This review explores these possibilities, with hopes of rekindling a critical discussion about venous IH that goes beyond thickness and AVF outcomes.

Repeated Endovascular Interventions Are Worthwhile, Even After Thrombosis, to Maintain Long-Term Use of Autogenous Dialysis Fistulas

OBJECTIVES

Patients often require multiple access re-interventions to improve fistula patency and the overall usable lifespan of autogenous arteriovenous fistula (aAVF). There is no consensus on the appropriate number of re-interventions after which an access should be abandoned and new access placed. We evaluated whether repeated endovascular interventions for failing/failed aAVF are worthwhile or futile.

METHODS

A retrospective review was performed on aAVFs created between 2009-2014. Fistula function was evaluated until January 2017. Functional fistula patency (FFP) was defined as the total time of functional fistula use for hemodialysis, from time of cannulation to time of measurement or fistula abandonment, including all interventions performed to maintain/reestablish patency. Primary outcomes were FFP duration and number of post-dialysis interventions.

RESULTS

The study included 163 patients. Mean age was 67 (SD = 15.03). The only variable statistically different between functional fistulas and abandoned fistulas was obesity (p = 0.03). At the end of the study period, 145 (89.0%) patients continued to have functional fistulas, and 73 (44.8%) patients died, but had functional fistulas at time of death. Median FFP for the functional group was 3.18 years (range 0.01-7.01 years) and median number of interventions was 1 (range 0-13). In 18 patients (11%), the fistula was abandoned, most commonly due to thrombosis (47.1%), followed by infection (23.5%). No fistula was abandoned because of an unacceptable rate of reintervention. Median FFP in the abandoned group was 0.91 years (range 0.03-5.30 years), and median number of interventions was 0 (range of 0-5).

CONCLUSIONS

Through repeated interventions on aAVFs, none of the patients in our study exhausted all hemodialysis access options prior to transplantation, death or loss to follow-up. These results may indicate repeated and/or more frequent revisions do not negatively affect the FFP nor do they increase the overall risk for abandonment of aAVFs.

Effectiveness and safety of repeated percutaneous intervention in an office-based endovascular center in maintaining hemodialysis access

OBJECTIVES

Percutaneous dialysis access interventions are routinely used to maintain the patency of dialysis access despite the lack of data regarding their long-term effectiveness. This retrospective study was undertaken to study the effectiveness and safety of percutaneous dialysis access interventions in arm fistulas and bridge grafts in an office-based endovascular center.

METHODS

Patients who had a percutaneous dialysis access intervention in their upper extremity access site, performed at a single office-based endovascular center over a nine-year period (2007-2016) were included in this study. The patients' demographic factors, patency, and complications were analyzed. Patients were entered in the study after first percutaneous dialysis access intervention.

RESULTS

A total of 298 limbs in 259 patients had 913 procedures carried out over a nine-year period. There were 190 access arteriovenous fistulas and 108 arteriovenous grafts. The two most common arteriovenous fistulas were the brachiocephalic fistula (n = 74, 39%) and radio cephalic fistula (n = 69, 36%). Arteriovenous grafts were most commonly placed in the upper arm (n = 66, 61%) followed by the forearm (n = 42, 39%). The mean overall patency for all limbs was 50.86 months. Arteriovenous fistulas had a significantly longer patency than arteriovenous grafts (51.65 vs. 42.09 months; P = 0.01). In addition, patients with two or more percutaneous dialysis access intervention in their arteriovenous fistula had significantly greater patency than those with only one percutaneous dialysis access intervention (58.5 vs. 7.6 months; hazard ratio 0.41; P = 0.0008). This was not true for the arteriovenous graft group. Women represented 49% of the patient group. Their accesses had shorter patency than men (39.8 vs. 60 months; P = 0.0007).

CONCLUSIONS

This data support the use of repeated percutaneous dialysis access intervention to maintain long-term patency of dialysis access sites in an office-based endovascular center. Overall, fistulas have longer patency than grafts and women have poorer outcomes as compared to men.

Predictors associated with early and late restenosis of arteriovenous fistulas and grafts after percutaneous transluminal angiography

BACKGROUND

The objective of this study was to assess postintervention patency and analyze the predictive factors associated with early and late restenosis after intervention in hemodialysis arteriovenous fistulas (AVF) and arteriovenous grafts (AVG).

METHODS

This study retrospectively analyzed 284 hemodialysis patients who underwent percutaneous transluminal angioplasty (PTA) due to AVF and AVG stenosis. A total of 350 PTA procedures were performed. Clinical, anatomical, biochemical, and technical variables were analyzed. Using univariate and multivariate analyses, we assessed the postintervention patency of PTA by follow-up, and identified the predictive factors taking into account competing risks.

RESULTS

Postintervention patency rates at 3, 6, 12, and 24 months were 86.5%, 66.4%, 42.6%, and 29.8%, respectively, with a median patency duration of 11±0.71 months. Kaplan-Meier analysis showed that the patency rate of the AVF group (n=271) was dramatically higher than the AVG group (n=79) at 3, 6, and 12 months after PTA, respectively (88.9% vs. 78.5%, 69.0% vs. 57.4%, 48.8% vs. 20.0%, P<0.01). Cox survival analysis revealed that the factors associated with postintervention patency of AVF included age of fistulas, serum albumin (ALB) levels, location of stenoses, lesion length longer than 2 cm, multiple stenoses, and maximal pressure of dilatation lower than 16 atm. In addition, factors related to postintervention patency of AVG included the presence of diabetes and hypertension, and serum ALB.

CONCLUSIONS

This study demonstrated that the risk factors associated with postintervention patency of AVF included age of fistulas, lower levels of serum ALB, location of stenoses, lesion length longer than 2 cm, multiple stenoses, and maximal pressure of dilatation lower than 16 atm. In addition, risk factors related to postintervention patency of AVG included the presence of diabetes and lower levels of serum ALB, while the presence of hypertension was found to be a protective factor for reducing patency loss of AVG. Among all these factors, serum ALB and multiple stenoses tended to predict early restenosis, while pressure of dilatation tended to predict late restenosis.

Effect of short-term low molecular weight heparin on patency following successful salvage of arteriovenous access with recurrent thrombosis

AIM

This study aims to investigate the effect of low molecular weight heparin (LMWH) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis.

METHODS

Following successful thrombectomy, 66 patients with recurrent thrombosis were included in the study. The primary, assisted primary and secondary patency rates of patients who received LMWH (n = 24) were compared with those who did not receive anticoagulant (n = 42) using Kaplan-Meier analysis. Cox-regression analysis was performed to investigate potential predictors of patency rates.

RESULTS

The mean dose of enoxaparin used was 40 ± 13.1 mg or 0.74 ± 0.2 mg/kg daily for a median duration of 14 (IQR 7,28) days. The mean trough anti-Xa concentrations measured after two doses of LMWH was 0.17 ± 0.13 IU/mL. Kaplan-Meier analyses for mean primary, assisted primary and secondary patency rates of LMWH vs no anticoagulation groups were 149 (95% CI: 91 - 207) vs 87 (95% CI: 42-132) days (P < .006), 230 (95% CI: 142-320) vs 107 (95% CI: 62-150) days (P = .01) and 438 (299-579) vs 294 (95% CI: 197-392) days (P = .08) respectively. LMWH remained a significant protective predictor of primary (HR: 0.49; 95% CI: 0.25-0.86; P = .02) and assisted primary patency rates (HR: 0.51; 95% CI: 0.27-0.98; P = .04) after adjusting for patient age, access age, type of AV access, presence of peripheral vascular disease and haemoglobin levels.

CONCLUSION

LMWH may improve short and mid-term patency rates for AV accesses with recurrent thrombosis.

Efficacy of Regional Anesthesia in Secondary Procedures or Revisions of Arteriovenous Fistula

BACKGROUND

Several factors affect the outcomes of arteriovenous fistula (AVF) and end-stage renal disease (ESRD). This study aimed to evaluate the efficacy of regional anesthesia in secondary procedures or revisions of AVF.

METHODS

Medical records of patients who underwent treatment for AVF secondary procedures or revisions under brachial plexus block (BPB) between March 2016 and June 2019 were retrospectively analyzed. Patient characteristics and clinical outcomes were evaluated.

RESULTS

In total, 375 patients (mean age 65.6 ± 12.74; males 210, 56.0%) were enrolled in the study and 770 procedures were performed under BPB for AVF secondary procedures or revisions. The procedures included endovascular treatment (385, 50.0%), surgical treatment (105, 13.6%), and hybrid treatment (280, 36.4%). In 180 procedures (23.4%) for AVF lesions, the operative field included a single segment of the arm, whereas in 590 procedures (76.6%), the operative field included multiple segments. In total, 37 (4.8%) cases of 30-day postoperative complications were observed, of which 33 (4.3%) were surgery-related complications, 2 (0.3%) were BPB-related complications (neurapraxia), and 2 (0.3%) were contrast agent allergic reactions; 34 (4.4%) reinterventions of the total 201 (26.1%) reinterventions were performed within 30 days postoperatively. The mean operation time was 87.5 ± 55.35 min. The pain score for all patients was 0 (no pain), and no patient demanded opioids postoperatively.

CONCLUSIONS

Ultrasound-guided BPB is safe and effective for AVF secondary procedures or revisions in ESRD patients.

Efficacy of the transjugular approach in endovascular intervention for hemodialysis access comparing with conventional approach

PURPOSE

Compared with the conventional approach, the benefits of the transjugular approach in endovascular intervention for hemodialysis access avoids complications due to direct puncture and reduces direct radiation exposure to the hands of operator. The aim of this non-inferiority study was to evaluate the efficacy of the transjugular approach in endovascular intervention for hemodialysis access comparing with conventional approach.

METHODS

We retrospectively assessed endovascular intervention for hemodialysis access performed in our hospital from 2012 to 2016, divided into the conventional approach group and the transjugular approach group. The hemodialysis access survival rate, re-intervention survival rate, and lesion characteristics were comparatively evaluated.

RESULTS

We included 223 cases in 118 patients (146 cases with conventional approaches and 77 cases with transjugular approaches). There was a higher incidence of thrombosis with the conventional approach (p < 0.001), however, no significant difference in the hemodialysis access type or main lesion location. The transjugular approach showed either a better hemodialysis access survival rate (p = 0.017) and a trend toward improved re-intervention survival rate (p = 0.098) than the conventional approach. Following classification according to the presence of thrombus, there was no significant difference in either the hemodialysis access survival rate or the re-intervention survival rate between the approaches with or without thrombus.

CONCLUSION

The transjugular approach could be performed in most cases and was similar to the conventional approach in terms of outcomes. The transjugular approach should be considered as an alternative to either replace or use in combination with the conventional approach in endovascular intervention for hemodialysis access.

Perioperative and long-term outcomes after percutaneous thrombectomy of arteriovenous dialysis access grafts

OBJECTIVE

Maintenance of functional arteriovenous grafts (AVGs) for dialysis is difficult secondary to low primary patency, need for reinterventions, and limited alternative dialysis access options. We assessed our experience with percutaneous thrombectomy for treatment of occluded AVGs.

METHODS

We performed a retrospective analysis of all percutaneous thrombectomies for AVGs from 2015 to 2017. These were generally performed using mechanical thrombectomy and occasional chemical tissue plasminogen activator thrombolysis, over-the-wire balloon embolectomy for inflow, and adjunctive inflow and outflow interventions as necessary. Perioperative outcomes, long-term patency, reinterventions, and need for new permanent access placement were analyzed.

RESULTS

There were 218 percutaneous thrombectomies performed on 86 AVGs in 77 patients. Approximately half (53.2%) of the patients were male and 68.8% were black. Mean age was 61.1 ± 13.0 years. At the time of thrombectomy, 73.8% underwent venous outflow interventions and 4.5% underwent arterial inflow interventions. Within 30 days, 24.8% of declotted grafts underwent repeated percutaneous thrombectomy, 14.3% required tunneled dialysis catheter placement, 4% developed minor access site or graft infections, and one patient underwent surgical arterial thrombectomy for arm ischemia. There were no venous thromboembolic, cardiopulmonary, or cerebrovascular complications or clinically significant pulmonary embolism. At 1 year and 3 years after percutaneous thrombectomy, freedom from repeated thrombosis was 37% and 18%, respectively, and freedom from new dialysis access placement was 66% and 51%, respectively. Overall patient survival was 82% at 3 years.

CONCLUSIONS

Percutaneous thrombectomy of AVGs is safe and is associated with acceptable patency rates. This minimally invasive method extends AVG use for these high-risk patients with limited dialysis access options.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Angiography and phlebography in a hemodialysis population: A retrospective analysis of interventional results

OBJECTIVE

To clarify the reasons and beneficial effects and duration of arteriovenous fistula patency after radiological interventions in arteriovenous fistula. The patients investigated were referred due to arteriovenous fistula access flow problems.

MATERIAL AND METHODS

In 174 patients, 522 radiological investigations and endovascular treatments such as percutaneous transluminal angioplasty were analyzed, retrospectively. All investigations were performed due to clinical suspicion of impaired arteriovenous fistula function.

RESULTS

Arterial stenosis was significantly more frequent among patients with diabetic nephropathy (p < 0.001) and interstitial nephritis (p < 0.001). According to the venous stenosis, the diagnosis did not affect the frequency (p = 0.22) or the degree (p = 0.39) of stenosis. The degree of stenosis prior to percutaneous transluminal angioplasty correlated significantly with the degree of remaining stenosis after intervention (p < 0.001). Of the 174 patients, 123 (71%) performed a total of 318 investigations including percutaneous transluminal angioplasty. Repeated percutaneous transluminal angioplasty was performed significantly more often in patients with diabetic nephropathy. The median times to the first percutaneous transluminal angioplasty and to the subsequent percutaneous transluminal angioplasties were 9.5 and 5 months, respectively. Arteriovenous fistula in patients with diabetic nephropathy performed similar to most other diagnoses, although performing more percutaneous transluminal angioplasty/patient than most other diagnoses.

CONCLUSION

Many patients could maintain long-term patency of arteriovenous fistula, including those with diabetic nephropathy, with repeated interventions; this motivates a closer follow-up for these patients. Clinically significant stenosis should be dilated as meticulously and as soon as possible. Occlusions of the arteriovenous fistula in most instances can be successfully thrombolyzed or dilated upon early diagnosis.

Factors affecting arteriovenous fistula dysfunction: A narrative review

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

Ultrasound-guided Angioplasty of Arteriovenous Fistulas for Hemodialysis: Benefits and Limitations

BACKGROUND

Ultrasound-guided percutaneous angioplasty of arteriovenous fistulas (AVFs) makes it possible to avoid contrast agents and X-rays, to optimize the puncture site and to locate some stenoses on the fistulography, but is it really useful? Our objective is to report the results of our experience.

METHODS

Between November 2012 and November 2017, all the patients treated according to this method in our center were collected retrospectively. The surgical indications were an insufficient maturation of the AVF, an increase in the venous pressure, an inadequate outflow, difficulties in puncture, a prolonged bleeding time, a flow drop, or an aneurysmal evolution.

RESULTS

During this period, 50 patients had 72 ultrasound-guided angioplasties, 64 on native AVFs (88.9%) and 8 on prosthetic AVFs (11.1%). The technical success rate was 100%. The average preoperative flow of AVFs was 506.8 ± 302.2 vs. 955.9 ± 371.4 mL/min after angioplasty. The mean duration of follow-up was 13.4 ± 12.9 months. The cumulative rates of primary, assisted primary, and secondary patency were 43.5%, 68.8%, 81.5% at 1 year and 31.7%, 63.9%, 76.8% at 2 years, respectively.

CONCLUSIONS

AVF angioplasty under ultrasound guidance only is feasible, effective, and represents an interesting alternative. A controlled study comparing ultrasound guidance with angioplasties performed under conventional angiographic guidance as the reference technique would better clarify the value of this technique.

Use of the Viabahn stent graft for the treatment of recurrent cephalic arch stenosis in hemodialysis accesses

OBJECTIVE

Cephalic arch stenosis (CAS) is a frequent and challenging failure mode of brachiocephalic fistulas. Natural tortuosity of the cephalic arch requires special consideration in selecting a treatment modality. Typical percutaneous angioplasty and bare-metal stent (BMS) treatments provide a short-term treatment solution for CAS without a durable effect. This study assessed Viabahn (W. L. Gore & Associates, Flagstaff, Ariz) stent grafts (SGs) as a first-line percutaneous option to provide a durable treatment for CAS.

METHODS

SG data were collected at a free-standing physician office between July 10, 2009, and January 26, 2011. A single-arm, prospective, observational study was conducted of 50 consecutive CAS patients treated with angioplasty followed by deployment of Viabahn SGs. Outcomes included target lesion primary patency and reintervention rates as well as secondary access patency. Results were compared with historic cohorts of percutaneous balloon angioplasty (N = 50) and angioplasty followed by BMS deployment (N = 50). The cohorts were treated between May 5, 2005, and May 20, 2010, and assessed in chronologic order.

RESULTS

The SG cohort target lesion primary patency reported at 3, 6, and 12 months was 90% ± 7%, 74% ± 12%, and 60% ± 14% (±95% confidence interval), respectively. Compared with historic cohorts, the SG cohort demonstrated statistically superior target lesion primary patency (P < .001), with a reduced reintervention rate per access-year (P < .001). Secondary access patency was statistically superior compared with the percutaneous balloon angioplasty cohort (P = .034) but not statistically different from the BMS cohort when assessed during a 2.5-year period. The secondary access patency for the SG cohort at 5 years was 80% ± 15%.

CONCLUSIONS

In treatment of a CAS, the Viabahn SG study group demonstrated superior target lesion primary patency and required fewer subsequent interventions compared with historic cohorts treated with angioplasty or angioplasty followed by BMS placement. Given the significant improvement in target lesion primary patency, future studies should challenge Viabahn SGs as a primary percutaneous treatment modality vs durable surgical alternatives.

Factors Affecting Patency following Successful Percutaneous Intervention for Dysfunctional Hemodialysis Vascular Access

BACKGROUND

This study aimed to investigate the patency following initial successful percutaneous transluminal angioplasty (PTA) for untreated dysfunctional hemodialysis vascular access and to identify predictors of PTA durability.

METHODS

This retrospective observational study included data of 132 consecutive initial PTA of hemodialysis vascular access in 126 patients who showed immediate technical and clinical success and had at least 1 year of follow-up data.

RESULTS

The mean duration of primary and secondary patency post-PTA was 16 and 27 months, respectively. On multivariate adjusted Cox regression analysis, dyslipidemia (P < 0.001), use of insulin (P = 0.016), and arteriovenous graft (AVG) (P = 0.016) were significantly associated with shorter primary patency. Dyslipidemia (P < 0.001), use of antiplatelet medication (P = 0.013), and failed vascular access (P = 0.004) were significant predictors of secondary patency loss. Use of statin was the only clinical variable associated with increased primary and secondary patency (P < 0.001). According to a subgroup analysis on the type of vascular access and dysfunction, primary and secondary patency rates were significantly higher in the arteriovenous fistula (AVF) and failing vascular access groups than AVG and failed vascular access groups, respectively. Early dysfunction (within 6 months) was significantly higher in the AVG and failed vascular access groups after initial PTA, but there was no significant difference after multiple PTAs.

CONCLUSIONS

Post-PTA primary and secondary patency rates were significantly higher with AVF and failing vascular access. The use of statin was associated with increased primary and secondary patency after initial successful PTA in this study.