Salvage of nonmaturing native fistulas by using angioplasty

The trans-radial approach for endovascular intervention of the problem arterio-venous fistula: A single-centre case series and systematic review

INTRODUCTION

The arteriovenous fistula (AVF) is the gold standard access modality for haemodialysis, but due to patient and technical factors, it is prone to stenosis and thrombosis. The trans-radial approach offers multiple unique benefits, but its safety, efficiency and efficacy have not been rigorously studied in the context of the AVF. This study provides a case series of trans-radial AVF procedures, and a systematic review and meta-analysis of existing literature to solidify the role of the trans-radial approach in endovascular AVF surgery.

METHODS

Surgical records were interrogated to identify all trans-radial AVF interventions between 2019 and 2021. The primary endpoints were procedure time and complication rates. The secondary endpoints were primary assisted patency and increase in pre- and post-operative brachial artery blood flow. The systematic review was performed by searching MEDLINE, Embase and CENTRAL from 2000 to 2023.

RESULTS

The case series identified 76 consecutive procedures performed on 49 patients. Mean procedure time was 64 min, and only one complication, a puncture site haematoma, was identified. Mean postoperative AVF flow increase was 342 mL/min (p < 0.001). Primary-assisted patency at 6 and 12 months was 91% and 82% respectively. The systematic review included 16 studies totalling 1163 procedures with a mean MINORS score of 69%. Mean procedure time was 44 min. Complications were rare: procedural failure (1.2%), haematoma (0.90%), radial artery occlusion (0.74%) and pseudoaneurysm (0.12%). Post-procedural flow increased by an average of 274 mL/min. Pooled primary-assisted patency rates at 6 and 12 months were 88% and 77% respectively.

CONCLUSION

The trans-radial approach allows for expedient, safe and durable AVF endovascular surgery, however this technique would benefit from prospective evaluation.

Outcomes of balloon-assisted maturation with large-diameter balloons

OBJECTIVES

Balloon-assisted maturation (BAM) is a well-established technique for maturation of inadequate arteriovenous fistulas (AVF). The objective of this study was to evaluate outcomes of initial BAM using large-diameter angioplasty balloons.

METHODS

Charts of patients who underwent BAM between 2018 and 2021 at a single academic institution were reviewed. AVF maturation rate was the primary outcome. Secondary outcomes included procedural complications, re-intervention rates, post-procedure vein diameter, and time to catheter-free hemodialysis (HD). Outcomes of patients that underwent initial BAM with ⩾7 mm diameter balloons (Group I) were compared to those of patients that had initial BAM with <7 mm balloons (Group II).

RESULTS

Group I (n = 149) was a significantly younger cohort and had more men compared to Group II (n = 90). There were no significant differences associated with procedural details and complication rates. Median vein diameter was larger (5.9 mm, IQR: 5-6.4) in Group I compared to Group II (5.1 mm, IQR: 4.2-5.9; p = 0.03) on post-procedure Duplex ultrasound. There was also a higher incidence of vein stenosis in Group II. The overall maturation rate was higher in Group I (97% vs 88%, p = 0.003), and a larger proportion of patients in Group II required more than one BAM to achieve maturation (33% vs 16%, p = 0.002). The median time to catheter-free HD after first BAM was 29 days (IQR: 19-47) in Group I and 42 days (IQR: 24-75) in Group II (p = 0.002). At 60 days after first BAM, the incidence of catheter-free HD was 83% in Group I versus 67% in Group II (p = 0.001).

CONCLUSIONS

Our study demonstrates that the ability to utilize large angioplasty balloons during initial BAM is associated with higher rates of AVF maturation with fewer re-interventions and shorter time to catheter-free dialysis. AVFs that can tolerate this procedure often have more favorable baseline characteristics.

Transjugular approach: comparison with conventional endovascular treatment of native arteriovenous fistulas

OBJECTIVES

The aim of this study was to compare the outcomes of the transjugular approach with those of the conventional approach for endovascular treatment of arteriovenous fistulas (AVFs).

METHODS

Between May 2015 and July 2019, 112 patients with endovascular treatment of dysfunctional or immature AVFs were included and divided into the transjugular (n = 46) and conventional (n = 66) groups. Electronic medical records and angiography of the patients were retrospectively reviewed to assess technical and clinical success rates, time to first fistulography, total procedure time, primary and secondary patency, and complications in both groups.

RESULTS

There were no significant differences in technical success rate (87.0% vs 97.0%; P = .062), clinical success rate (80.4% vs 90.9%; P = .109), or total procedure time (60.2 vs 57.9 min; P = .670) between the groups. Cox proportional hazards models showed that the cumulative primary patency was significantly higher in the transjugular group than in the conventional group (P = .041; 6-month patency rates, 93.8% vs 91.5%). Also, a statistically significant difference was found between the cumulative secondary patency of the groups (P = .014; 6-month patency rates, 91.4% vs 86.5%). No major complications were observed.

CONCLUSIONS

Transjugular endovascular treatment of AVFs was successful and effective. Longer patency periods were observed when treated via transjugular access.

ADVANCES IN KNOWLEDGE

This article compared the outcomes of transjugular approaches with those of conventional approaches in the endovascular treatment of native AVFs and showed higher patency periods/rates in the transjugular group than in the conventional group.

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.

Management of Immature Arteriovenous Fistulas

In patients requiring long-term hemodialysis for chronic kidney disease, an arteriovenous fistula is the preferred mode of hemodialysis access over synthetic arteriovenous graft or hemodialysis catheters. The National Kidney Foundation recommended in their Kidney Dialysis Outcomes Quality Initiative (KDOQI) Clinical Practice Guidelines that the creation of an autogenous arteriovenous fistula should initially be sought whenever possible. In 2003, a program named the Fistula First Breakthrough Initiative was initiated in the U.S. to increase the use of arteriovenous fistula for hemodialysis and to ultimately surpass the goal of 50% fistula use in incident and 40% fistula use in prevalent hemodialysis patients per recommendation by KDOQI Guidelines. While this goal was achieved, the encouraged creation of arteriovenous fistulas saw a rise in fistulas that failed to mature. Researchers have focused on developing strategies to optimize fistula maturation. Studies have revealed that the presence of stenoses and accessory draining veins may contribute to unsuccessful fistula maturation. Endovascular treatment, including balloon angioplasty and accessory vein embolization, aim to correct anatomical factors that negatively affect the maturation process. This article reviews the techniques and outcomes of endovascular treatment in the management of immature fistulas.

Maintenance and Salvage of Hemodialysis Access

Many end-stage kidney failure patients require hemodialysis as a life-sustaining treatment. Hemodialysis access via arteriovenous fistula or graft creation is preferred over long-term dialysis catheters, but intervention to maintain patency and prevent access failure is common. Endovascular and open surgical techniques are both utilized to address the underlying etiology of failure. Endovascular options include balloon angioplasty, angioplasty with stenting, and drug-eluting stents. Open revision is commonly needed for recurrent stenosis, aneurysmal or pseudoaneurysmal change, hemodialysis access-induced distal ischemia, and infection. Treatment plans should be guided by patient's individualized goals of care and require a multidisciplinary approach to the management of this complex disease.

Oversized balloon angioplasty for endovascular maturation of arteriovenous fistulae to accelerate cannulation and to decrease the duration of catheter use

BACKGROUND

The functional autologous arteriovenous fistula is considered the best vascular access for patients on hemodialysis. Some fistulae exhibit maturation problems after creation and do not reach adequate vessel diameter and flow in dialysis. The aim of this study was to describe our technique of oversized balloon angioplasty for assisted maturation of arteriovenous fistulae to accelerate the cannulation and to decrease the time of catheter use and its outcome.

METHODS

A retrospective analysis of balloon-assisted procedures for maturation failure was performed in a single center between October 2011 and January 2019. Patients underwent imaging procedures to identify stenosis, followed by angioplasty using oversized high-pressure balloons from the anastomosis to the deep venous outflow tract. The flow volume, time interval of use of the fistula and removal of the catheter, patency rates, and complications rates were evaluated.

RESULTS

Seventy-eight patients underwent 124 balloon angioplasty procedures. Technical and clinical success was achieved in 91% of the cases. In patients in whom maturation was successful, the fistula was cannulated in a mean time of 5 days after the procedure (range, 1-20 days). On average, catheter removal was performed 14 days (range, 5-33 days) after the maturation procedure. The mean flow volume in the fistula before the procedure was 276 ml/min (range, 122-488 ml/min) and 24 h after the maturation was 1014 ml/min (range, 760-1800 ml/min).The primary patency rate at 3, 6, and 12 months was 87.3%, 66.2%, and 50.7%, respectively. Assisted primary patency was 100% at 3 months, 92.9% at 6 months, and 90.0% at 12 months. Minor complications occurred in 18% of cases, and major complications in 4.8%.

CONCLUSIONS

The oversized balloon-assisted arteriovenous fistula maturation technique is safe and effective, allowing the cannulation of the fistulae a few hours or days after the procedure and decreasing the time of catheter use.

Accessory Vein Obliteration and Balloon-Assisted Maturation for Immature Arteriovenous Fistulas for Haemodialysis: A Systematic Review and Meta-Analysis

PURPOSE

This study aims to examine outcomes of immature arteriovenous fistula salvage using balloon angioplasty (PTA) without and with accessory vein obliteration (PTA + VO).

MATERIALS AND METHODS

PubMed and Embase were accessed on 21 September 2020 to retrieve cohort studies on adult patients with end-stage renal failure (ESRF) requiring dialysis. Risk of bias was assessed using Newcastle-Ottawa Scale. Studies were pooled into PTA or PTA + VO arms, with outcomes (technical/clinical success, primary/secondary post-intervention patency until 12 months) reported as event rates with 95% confidence intervals. Random-effects model and maximum likelihood meta-regression were used for meta-analysis.

RESULTS

Fourteen studies (1030 participants) were included. The between-subgroup difference in outcomes was largely non-significant (p > 0.050).

CONCLUSION

The evidence does not support balloon angioplasty with concomitant accessory vein obliteration for immature fistula salvage.

Ultrasound guided interventional procedures on arteriovenous fistulae

Autogenous (AVF) and prosthetic (AVG) arteriovenous fistulas are the vascular accesses (VA) of choice for hemodialysis thanks to their improved patency, reduced costs, and lower rate of infections relative to catheters.

In an effort to maximize the number of primary AVF and AVG, shorten maturation times for AVF, and reduce the number of indwelling catheters, several new techniques have been developed within the context of an overall program designed to optimize access care.

This approach includes: (a) Primary Intraoperative Balloon Angioplasty on the vessels selected for AV creation whether small-sized or altered by pre-existing lesions; (b) Percutaneous Transluminal Angioplasty (PTA) on AVF and AVG stenosis, performed under ultrasonographic (UG) or fluoroscopic guide (FG).

We report the experience of two Center in performing the above mentioned procedures on even complex VA. The wise adoption of these techniques may avail to meet the stringent demands for reliable VA placement as defined by KDOQI and, thereby, expand the duration and quality of life for hemodialysis patients.

Better Efficacy of Balloon Assisted Maturation in Radial-Cephalic Arteriovenous Fistula for Hemodialysis

Purpose

Native arteriovenous fistula (AVF) is the first choice for hemodialysis access; however, the maturation failure rate remains high. Hence, balloon-assisted maturation (BAM) is increasingly being used to overcome maturation failure. This study evaluated the outcomes of BAM and compared the differences between radial-cephalic (RC) and brachial-cephalic (BC) AVF.

Methods

Materials and Between January 2013 and December 2017, 1,622 new AVFs were created. BAM was considered if the AVF did not satisfy the criteria for hemodynamic maturation (6-mm diameter and 500-mL/min flow rate within 8 weeks after the operation).

Results

Of the 1,622 AVFs, BAM was performed in 142 patients (8.75%). There were 92 RC and 50 BC AVFs. Multivariate analyses revealed that ipsilateral central vein catheter history was the sole risk factor for maturation failure after BAM. One-year functional primary patency (FPP) and functional secondary patency (FSP) in RC AVFs were higher than those in BC AVFs without statistical significance (FPP, RC vs. BC: 70.9% vs. 50.9%, P=0.099; FSP, 95.5% vs. 81.1%, P=0.146). Further, based on the multivariate analysis, the independent risk factors for FPP in the RC and BC AVFs were the number of BAMs (odds ratio [OR], 3.05; 95% confidence interval [CI], 1.11-8.37; P=0.03) and age (OR, 1.04; 95% CI, 1.00-1.07; P=0.04), respectively.

Conclusion

BAM is a relatively good salvage method with tolerable patency. However, the risk factors for patency and the outcomes of BAM differ between RC and BC AVFs.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Percutaneous intervention for salvage of non-maturing arteriovenous fistulas: Which is the better approach, arterial or venous?

Objectives

To evaluate the efficacy and long-term patency of endovascular treatment for non-maturing native arteriovenous fistulas according to the approach route (arterial vs. venous).

Methods

Eighty-five patients underwent percutaneous transluminal angioplasty for non-maturing fistulas (63 radiocephalic and 22 brachiocephalic) between 2010 and 2019. Outcome variables such as procedural success, complications, and primary and secondary patency rates were analyzed from the patients’ demographic, angiographic, clinical, and hemodialysis records according to the approach route (venous access group, n = 53 and arterial access group, n = 32). The Kaplan-Meier method was used to analyze the patency rates.

Results

The mean duration from fistula creation to fistulography was 78.4±51.4 days (range, 1–180 days). The anatomical and clinical success rates were 98.8% and 83.5%, respectively. Lesions were most commonly located at the juxta-anastomosis (55.3%). Accessory cephalic veins were observed in 16 patients. The primary patency rates were 83.9%, 71.9%, and 66.3% and the secondary patency rates were 98.6%, 95.9%, and 94.2% at 3 months, 6 months, and 1 year, respectively. The degree of hypertension (P = 0.023), minimal preoperative vein size (P = 0.041), and increment in postoperative vein diameter were higher in the venous access group than in the arterial access group (P<0.01). The frequency of using cutting balloons (P = 0.026) and complication rate were higher in the arterial access group than in the venous access group (arterial access: 1 major, 8 minor; venous access: 4 minor; P = 0.015).

Conclusions

Aggressive evaluation and endovascular therapy can salvage most non-maturing fistulas. Transradial and distal radial approaches can be effective even for challenging lesions.

Maturation Rates of Arteriovenous Fistulas Using Small Veins in the Era of Endovascular Interventions

BACKGROUND

Traditional practice suggests the abandonment of veins smaller than 3 mm in diameter for arteriovenous fistula (AVF) creation because of a low rate of maturation. This study aims to show that with balloon-assisted maturation (BAM), undersized veins can be used to create functional AVFs with a high rate of success.

METHODS

All patients who underwent AVF creation between 2014 and 2018 at a tertiary academic medical center were retrospectively reviewed. The patients without preoperative vein mapping, those who failed to follow-up, and the patients who were not on dialysis were excluded. A fistula was considered to be mature if it was successfully cannulated for dialysis. A total of 596 patients were identified for analysis. The cohort was divided into the small-vein group (SVG, <2.5 mm) and large-vein group (LVG, ≥2.5 mm) based on preoperative vein size. Categorical variables were analyzed with the chi-squared test for their association with maturation status. Continuous variables were analyzed with the Wilcoxon rank sum test. A P-value less than 0.05 was considered significant.

RESULTS

In the study cohort, 61.9% of the patients were male, with an average age of 62.8 ± 13.7 years, and an average preoperative vein size of 2.9 ± 1.1 mm. With similar demographic distribution, the participants in the SVG (n = 216) had significantly smaller preoperative vein size of 1.9 ± 0.4 mm than the patients in the LVG (n = 380), 3.5 ± 0.8 mm (P = 0.001). There were significantly more radio-cephalic AVFs created in the SVG (77.8% versus 48.7%, P < 0.0001). The overall maturation rate was 83.1% (n = 495), 219 fistulas (36.7%) matured primarily and 276 (46.3%) required interventions. Ninety-one percent of the patients required only 1 or 2 BAMs to achieve maturation. The SVG achieved a maturation rate of 75.9% as compared with 87.1% in the LVG (P = 0.002). A significantly higher number of patients in the SVG required BAM for maturation as compared with the LVG (67.7% versus 49.9%, P = 0.0002); however, there was no difference in the average number of BAMs required for fistula maturation between the groups (1.5 ± 0.8 for the SVG vs. 1.4 ± 0.7 for the LVG). In multivariable logistic regression analysis, vein size ≥2.5 mm (odds ratio (OR) = 2.11, confidence interval (CI): 1.36-3.27, P = 0.0009) and male sex (OR = 2.30, CI: 1.49-3.57, P = 0.0002) were independent predictors of maturation.

CONCLUSIONS

Small veins can be used for AVF creation with lower but still favorable maturation rates using BAM interventions, especially in male patients. This practice can increase the creation of autogenous dialysis access and potentially reduce complications related to prosthetic dialysis access.

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.

Diagnosis and Treatment of Nonmaturing Fistulae for Hemodialysis Access via Transradial Approach: A Case-Control Study

PURPOSE

To compare outcomes of transradial access for endovascular treatment of nonmaturing hemodialysis fistulae compared to brachial arteriography followed by unidirectional or bidirectional fistula access for intervention.

MATERIALS AND METHODS

In this institutional review board-approved, retrospective, case-control study, 56 consecutive patients with nonmaturing arteriovenous fistulae underwent percutaneous intervention between 2015 and 2018. The transradial group (n = 28) underwent radial artery access for diagnostic fistulography and intervention. The control group (n = 28) underwent retrograde brachial artery access for fistulography followed by unidirectional/bidirectional fistula access for intervention. Both groups had similar demographics, fistula characteristics, and stenosis locations.

RESULTS

Fewer punctures were required in the transradial group compared to controls (1.2 vs 2.4, P < .0001), and procedure time was shorter (64.9 vs 91.3 minutes, P = .0016). Anatomic, technical, and clinical success rates trended higher in the transradial group compared to controls (93% vs 86%, 96% vs 89%, and 82% vs 64%, respectively). Nonmaturation resulting in fistula abandonment was lower in the transradial group (3.7% vs 25%, P = .025). Primary unassisted patency at 3, 6, and 12 months was 77.1% ± 8.2%, 73.1% ± 8.7%, and 53.3% ± 10.6% in the transradial group, respectively, and 63.0% ± 9.3%, 55.6% ± 9.6%, and 48.1% ± 9.6% in the control group, respectively (P = .76). Primary assisted patency at 12 months was 92.3% ± 5.3% in the transradial group compared to 61.8% ± 9.6% at 12 months in the control group (P = .021). No major complications occurred. Minor complications were lower in the transradial group than in the control group (14% vs 39%, P = .068).

CONCLUSIONS

Treatment of nonmaturing fistulae via a transradial approach was safe, improved midterm patency, and was associated with lower rates of fistula abandonment.

Two-year cumulative patency of endovascular arteriovenous fistula

BACKGROUND AND OBJECTIVES

The recent advent of a device to create a proximal radial artery arteriovenous fistula using an endovascular approach to create the anastomosis represents a significant advance in dialysis access creation. This endovascular arteriovenous fistula offers the beneficial attributes of the proximal radial artery arteriovenous fistula while adding the advantages of avoiding a surgical procedure. The endovascular arteriovenous fistula can be created safely, functions well, has excellent patency, and has a high degree of patient satisfaction. The purpose of this study is to report the 2-year cumulative patency rate for a large multicenter cohort of endovascular arteriovenous fistula cases.

DESIGN

An endovascular arteriovenous fistula was created in 105 patients using either local or regional anesthesia and conscious sedation. Patient data were obtained from each program's electronic health record system. Data collection was truncated at 2 years postprocedure and used to calculate cumulative patency. Post-access creation patient satisfaction was assessed.

RESULTS

A physiologically mature arteriovenous fistula (blood flow ⩾500 mL/min and a target vein internal diameter ⩾4 mm) was obtained in 98%. A clinically functional arteriovenous fistula (supporting two-needle dialysis according to the patient's dialysis prescription) was demonstrated in 95%. Access failure resulting in the loss of access occurred in eight cases during the study period. The cumulative patency rate at 6, 12, 18, and 24 months was 97.1%, 93.9%, 93.9%, and 92.7%, respectively. The post-procedure patient evaluation emphasized a high level of patient satisfaction.

CONCLUSION

The proximal radial artery arteriovenous fistula created using an endovascular approach for the anastomosis is associated with excellent 2-year cumulative patency and is associated with a high level of patient satisfaction.

The influence of a doppler ultrasound in arteriovenous fistula for dialysis failure related to some risk factors

INTRODUCTION

The increasing prevalence of chronic kidney disease has increased the demand for arteriovenous fistula (AVF) care. The objective of this study was to assess the relationship between some risk factors for AVF failure (advanced age, female sex, diabetes, obesity, central venous catheter, previous fistula, and hospitalization) and having a Doppler ultrasound performed preoperatively.

METHODS

A prospective study was performed with 228 dialysis patients from Imperatriz, Maranhão. Half of the sample was randomly selected to receive preoperative Doppler ultrasound and the other half did not, from the period of October 2016 to September 2018.

RESULTS

There were 53 total failures corresponding to 23.2% of our sample, which is almost double that of the patients in the clinical group. Considering the failures and risk factors associated with the overall sample, there was a statistically significant association between a central venous catheter on the same side of the AVF with P = 0.04 (Odds Ratio 1.24) and obesity with P = 0.05 (Odds Ratio 1.36), which was not repeated in the Doppler ultrasound group individually. There was no statistically significant difference between the Doppler group and clinical group with respect to the amount of days of previous AVF hospitalization and failure.

CONCLUSIONS

We concluded that the reduction of failures with an introduction of the Doppler was statistically significant in the overall sample, but establishing a relationship between specific risk factors and failure was only possible with two of the risk factors in the study - obesity and central venous catheter on the same side of the AVF.

Endovascular salvage of non-maturing autogenous arteriovenous fistulas by using angioplasty and competitive vein embolization

INTRODUCTION

The aim of this study is to evaluate the maturation and patency rates after endovascular treatment of non-maturing arteriovenous fistulas with percutaneous transluminal angioplasty, embolization of competitive veins, or a combination of both in a series of consecutive patients.

MATERIAL AND METHODS

Retrospective evaluation of patients with non-matured arteriovenous fistulas treated in our hospital was performed. Fistulography and ultrasonography was performed in all patients to evaluate the presence of stenosis and competitive veins. Significant stenoses (> 50%) were treated with balloon angioplasty and competitive veins (accessory and collateral veins) with coil embolization.

RESULTS

A total of 78 fistulas were treated. Angioplasty and coil embolization were performed in 73 and 51 patients, respectively. No major complications occurred. In 65 out of 78 arteriovenous fistulas (83%), successful cannulation with two needles was possible after endovascular treatment. Sixty-three arteriovenous fistulas (81%) were used successfully for at least 3 months. Accessory veins were the only lesion present in 14% of the arteriovenous fistulas; coil embolization of these accessory veins resulted in 100% successful maturation. The estimated 3, 6, and 12 months postintervention assisted primary patency rates were, respectively, 73%, 55%, and 45%. The estimated 3, 6, and 12 months postintervention secondary patency rates were, respectively, 81%, 78%, and 73%.

CONCLUSION AND DISCUSSION

Angioplasty and coil embolization are successful and safe procedures that can convert a non-mature fistula into a mature one in more than 80% of patients. Accessory vein embolization may be more important than collateral vein embolization in the presence of stenosis.

Factors Associated with Secondary Functional Patency After Percutaneous Transluminal Angioplasty of the Early Failing or Immature Hemodialysis Arteriovenous Fistula

PURPOSE

To evaluate the efficacy of percutaneous transluminal angioplasty for early failing hemodialysis arteriovenous fistulas (AVFs) and predictors of secondary functional patency (FP).

METHODS

A review of our endovascular registry database showed that 61 patients with early failure after a surgically created AVF underwent endovascular intervention between 2011 and 2016. Median time from AVF creation to first intervention was 5.6 weeks. Median duration of follow-up was 14 months. Items related to the technical success rate and primary and secondary FP, and factors associated with secondary FP were analyzed.

RESULTS

Technical success was achieved in 55 (90%) of 61 patients. The primary and secondary FP rates were 42% and 65% at 12 months, respectively. Multivariate analysis showed that lesion length (HR; 1.15, P = 0.001) and lesions including juxta-AVF (the portion of fistula vein within 2 cm of the arteriovenous anastomosis, HR; 6.23, P = 0.008) were factors associated with reduced secondary FP. ROC curve analysis indicated lesion length with cutoff value ≥ 9 cm as a risk factor for reduced secondary FP. Secondary FP at 12 months for patients with no risk factors, with 1, and with 2 was 86%, 65%, and 0%, respectively. There was a significant difference in secondary FP rates among these groups (P = 0.001).

CONCLUSIONS

A lesion length and juxta-AVF lesion are the risk factors for reduced secondary FP. The secondary FP rate at 12 months is acceptable in patients without risk factors.

Endovascular management in immature arteriovenous fistula for hemodialysis

To evaluate the outcomes and prognostic factors of endovascular management in immature arteriovenous fistula (AVF) for hemodialysis.From April 2007 to September 2017, 54 patients (male:female = 31:23, mean age 65.63 years, range 33-90 years) who underwent endovascular management for the salvage of immature AVF were retrospectively reviewed. Clinical data, procedural details, and results were evaluated. Primary and secondary patency rates and factors influencing the patency were also analyzed.Technical and clinical success rates were 88.9% (48/54) and 85.2% (46/54), respectively. Mean primary and secondary patency was 42.10 (±8.85) and 91.5 (±14.77) months, respectively. Primary and secondary patency rates were 66% and 89% in 1 year, 66% and 78% in 2 years, and 51% and 78% in 3 years. In multivariate analysis, only brachiocephalic AVF and antegrade access procedures showed significantly shorter primary patency (HR 5.196; 95% CI (1.04-25.77); P = .044, HR 8.096; 95% CI (1.36-48.00); P = .021). There was no statistically significant factor associated with secondary patency in the multivariate study.Endovascular management in immature AVF is safe and effective to make the AVF available. Brachiocephalic AVF and antegrade access procedures are the factors influencing the patency in multivariate analysis.

Long Thoracic Vein Embolization for the Treatment of Breast Edema Associated with Central Venous Occlusion and Venous Hypertension

Purpose

Breast edema is a rare complication in hemodialysis patients with central venous occlusions. The present study sought to determine whether coil embolization of the long thoracic vein is an effective long-term treatment for this pathology.

Methods

The study patients were 6 female hemodialysis patients whose primary clinical manifestation of central vein occlusion was breast edema. When conservative treatment (allowing collaterals to dilate over time), as well as recanalization of occlusions through angioplasty with or without stent placement, failed to alleviate symptoms, patients underwent coil embolization of the long (lateral) thoracic vein.

Results

In 4 of the 6 cases, the breast edema was completely resolved without recurrence, while the other 2 patients experienced durable symptomatic improvement with only mild residual swelling. Average follow-up was 22 months. There were no adverse sequelae and none of the patients experienced increased swelling elsewhere following the coil embolization procedure.

Conclusions

Coil embolization of the long thoracic vein effectively alleviates breast edema in hemodialysis patients with elevated venous hydrostatic pressure due to central venous occlusions.

Aggressive Approach to Salvage Non-Maturing Arteriovenous Fistulae: A Retrospective Study with follow-up

Purpose

To establish a standardized approach for the maturation of non-maturing arteriovenous fistulae.

Methods

consecutive patients (n=122) with non-maturing fistulae presented to our outpatient vascular access center for percutaneous interventions to assist in maturation. The techniques used included flow rerouting, competing branch vein elimination, staged balloon angioplasty, and limited controlled extravasation.

Results

Successful fistula maturations were achieved in 118/122 patients. Fistulae were divided into two classes according to initial vessel size: class 1 (6.0–8.0 mm diameter, >6 mm deep) and class 2 (2.0–5.0 mm diameter) fistulae were evaluated for differences in technical procedures and clinically successful fistula maturation. Class 1 and class 2 fistulae were evaluated for mean number of procedures to maturation (1.6 and 2.6, respectively), and time to maturation (5 and 7 weeks, respectively). Follow-up for 109 of the initial 118 patients was achieved (mean=24 months, range=0.25–60 months). Class 1 and class 2 fistulae had primary patencies of 17 and 39% at 6 months; and secondary patencies of 72 and 77% at 12 months, 53 and 61% at 24 months, and 42 and 32% at 36 months, respectively. Primary and secondary patencies (Mann-Whitney test, p=0.44 and p=0.38, respectively) of class 1 and class 2 fistulae did not differ significantly, and secondary patencies were comparable to other fistula salvage studies.

Conclusion

Fistula salvage attempts should not be limited by factors such as a diffusely small diameter or an inaccessibly deep position.

Transjugular Venous Approach for Endovascular Interventions in Hemodialysis Grafts and Fistulas of the Upper Extremities

OBJECTIVE

This article describes the use of a transjugular venous access for interventions in upper extremity hemodialysis arteriovenous fistulas (AVFs) and grafts. This access is used in selected patients in whom direct puncture of the hemodialysis access is considered to be difficult or cumbersome. Technical success was achieved in 96.7% of patients. If an intervention is unsuccessful, the transjugular access offers the possibility of placement of a dialysis catheter for temporary or long-term hemodialysis.

CONCLUSION

The transjugular approach for hemodialysis access endovascular interventions is technically successful and safe. Initially described as an intervention to treat malfunctioning arteriovenous grafts, we have used it successfully in AVF interventions. In our opinion, this approach is a safe and effective alternative that may prove useful in selected patients.

Transjugular venous approach for endovascular intervention in upper-extremity dialysis access fistulae and grafts

A transjugular venous access is an alternative approach for endovascular intervention in upper-extremity dialysis arteriovenous fistulae and grafts. The transjugular access is recommended for patients who have an unfavorable anatomy for the direct arm access approach. Ultrasound evaluation of the arteriovenous access is essential before intervention and includes evaluation of the inflow artery and outflow vein diameters, arteriovenous anastomosis, and the entire outflow vein, specifically looking into potential problem areas. Patency of the ipsilateral internal jugular vein needs to be assessed. If patency of the ipsilateral internal jugular vein is confirmed, it can be used for access. Retrograde access into the outflow vein is obtained with a reverse-curve catheter and a Glidewire. In some cases, puncture of the outflow vein is necessary along with the use of snares to direct the catheter system into the outflow vein. The techniques for intervention are described. Successful access into the outflow vein is possible in >95% of cases. The technique is useful for fistula maturation, declotting procedure, and arteriovenous fistula and graft maintenance. If intervention is unsuccessful, the transjugular access offers the possibility of placement of a dialysis catheter for temporary or long-term dialysis.

Angiography of Hemodialysis Fistulas and Grafts

Angiography of the dialysis access is an important procedure in dealing with dialysis arteriovenous access (AVA) dysfunction. It is an integral part and the initiating procedure for all the interventional procedures performed for the management and salvage of dialysis AVA. The performance of this procedure and normal dialysis access-related anatomy including anatomical variants are discussed. In addition, pathology commonly encountered in association with the anatomy is reviewed.

Evaluation of Diagnostic Values of Clinical Assessment in Determining the Maturation of Arteriovenous Fistulas for Satisfactory Hemodialysis

BACKGROUND

Fistulas are the preferred permanent hemodialysis vascular access, but a significant obstacle to increasing their prevalence is the fistula's high "failure to mature" (FTM) rate. This study aimed to identify postoperative clinical characteristics that are predictive of fistula FTM.

MATERIALS AND METHODS

This descriptive cross-sectional study was performed on 80 end-stage renal disease patients who referred to Al Zahra Hospital, Isfahan, for brachiocephalic fistula placement. After 4 weeks, the clinical criteria (trill, firmness, vein length, and venous engorgement) examined and the fistulas situation divided to favorable or unfavorable by each criterion, and the results comprised with dialysis possibility. Data were analyzed with SPSS version 21. Diagnostic index for CLINICAL examination was calculated.

RESULTS

Among the 80 cases, 25 (31.2%) female and 55 (68.8%) male were studied with the mean age of 51.9 (standard deviation = 17) year ranged between 18 and 86 years old. Sixty-two (77.5%) cases had successful hemodialysis. All four clinical assessments were significantly more acceptable in patients with successful dialysis (P < 0.001). According to the results of our study, the accuracy of all physical assessments was above 70% and except vein length other criteria had a sensitivity and negative predictive value of 100%. In this study, firmness of vein has highest specificity and positive predictive value (83.9% and 64.3%, respectively).

CONCLUSION

Results of our study showed that high sensitivity and relatively low specificity of the clinical criterion. It means that unfavorable results of each clinical criterion predict unfavorable dialysis. Clinical evaluation of a newly created fistula 4-6 weeks after surgery should be considered mandatory.

Percutaneous Endovascular Treatment to Salvage Non-Maturing Arteriovenous Fistulas in a Multiethnic Asian Population

Introduction: An arteriovenous fistula (AVF) is the preferred method for haemodialysis in patients with end-stage renal failure. Previous studies have shown value in attempting percutaneous transluminal angioplasty (PTA) to salvage AVFs that fail to mature, but they are relatively small in size and mainly reported in Western populations. We reviewed our data of PTA in non-maturing AVFs to establish whether this technique is translatable to our local multiethnic population. Materials and Methods: We retrospectively reviewed the medical records and procedural images of 105 patients who had PTA for non-maturing AVFs performed at our department from January 2008 to January 2011. Technical success was defined as ≤30% residual stenosis after angioplasty. Clinical success was defined as at least 1 successful haemodialysis session within 4 weeks after PTA. Results: All 105 patients underwent angioplasty for at least 1 haemodynamically significant stenosis. Six (5.7%) had additional embolisation of accessory veins. Technical success was achieved in 95.2% of cases. The clinical success rate was 76.2%. Primary patency rates at 3, 6 and 12 months were 83%, 45% and 28%, respectively. Secondary patency rates at 3, 6 and 12 months were 90%, 79% and 70%, respectively. The minor complication rate was 18.1%. No major complications were encountered. An average of 1.7 interventions per access-year was required to maintain AVF patency. Patients with a preoperative vein size >2.0 mm and age <55 years were more likely to achieve clinical success, although not statistically significant. Conclusion: PTA is a viable option to help salvage non-maturing AVFs in a multiethnic Asian population. Key words: Angioplasty, Chronic renal disease, Haemodialysis, Interventional radiology

Transjugular Access for Endovascular Treatment of Immature Autogenous Arteriovenous Fistulae

PURPOSE

To assess the feasibility and outcome of transjugular access for endovascular treatment of immature arteriovenous fistulae (AVFs).

MATERIALS AND METHODS

Between August 2013 and January 2016, 90 patients (mean age, 64.5 y ± 12.8) underwent endovascular treatment of immature AVFs via transjugular access. The mean age of fistulae was 3.3 months ± 1.8. Total procedure time and technical and clinical success rates of endovascular procedures were assessed. Primary and secondary patency rates were calculated according to the Kaplan-Meier method, and complications were assessed.

RESULTS

All patients had inflow lesions, among which 19 (21.1%) had occlusions. The juxtaanastomotic segment was the most common site (44.3%). Transjugular access was successful in 83 patients (92.2%), and 7 required additional standard or transarterial access. The mean procedure time was 36.5 minutes. Technical and clinical success rates were 98.9% and 90.5%, respectively. Mean primary and secondary patency durations were 14.3 months ± 1.7 and 31.0 months ± 0.7, respectively. Primary patency rates at 3, 6, and 12 months were 84.4%, 67.3%, and 48.8%, respectively. Secondary patency rates at 6 and 18 months were 98.6% and 95.5%, respectively. Venous rupture occurred as a result of balloon inflation in 9 patients (10%), and was managed by balloon tamponade. There were no complications related to transjugular access during a mean follow-up period of 12.6 months.

CONCLUSIONS

Transjugular access for angioplasty of immature AVFs is feasible and safe. Potential problems associated with access in the outflow vein could be avoided by transjugular access.

Interventions for Failed Wrist Fistulae: Is it Worthwhile?

A well-functioning forearm fistula is considered as the most suitable access for dialysis. It is easy to construct, has the fewest number of complications and lasts for a long time. Many patients fail to enjoy this benefit due to the high rates of thrombosis and the failure to mature associated with this procedure. Attempts to salvage failed and failing fistula suggest that there is a group of patients where interventions can help provide this benefit. This article provides a brief review of current experience using surgical and interventional techniques to salvage failing forearm fistulae. It attempts to classify modes of presentation of access failure and different modalities used to salvage them. It also suggests an algorithm that can be used to identify patients who may benefit from these interventions and a guide to make the decisions related to selection of a treatment modality. Successful salvage of a failing forearm fistula provides the patient with an opportunity to enjoy all the benefits of this access.

Heparin-bonded expanded polytetrafluorethylene grafts in hemodialysis access

When options for autologous arteriovenous (AV) fistulas have been fully exhausted, AV grafts continue to play an important role in access creation for hemodialysis, offering long-term hemodialysis access that is a better alternative to central vein catheters. The drawbacks of AV grafts are their poor patency, infection and higher cost. Their main advantages are that they are widely available, are easy to create, and mature early. In the context of the "Fistula First" initiative, many patients with low quality veins suffer from fistula failure and non-maturation resulting in prolonged catheter days that would otherwise be prevented by initial creation of an AV graft. Endeavors to improve graft patency include administration of pharmacological agents, changing graft configuration, altering graft biology, and altering the graft surface. In this review, the current status of heparin-bonded AV grafts for hemodialysis is discussed.

Accessory Vein Obliteration for Early Fistula Failure: A Myth or Reality?

Early fistula failure (EFF) is a significant clinical problem causing lower rates of arteriovenous fistulae (AVFs) use in patients with ESRD on hemodialysis. The 2 main factors amenable to treatment and widely accepted to cause EFF are stenosis anywhere in the AVF circuit and/or presence of accessory vein (av). The role of stenotic lesions in causing EFF and their treatment options are relatively better defined with clear guidelines. On the other hand, assessing the significance of an av in causing EFF and the indications for its treatment seem to lack scientific recommendations based on robust clinical data. In this article, we review the pathophysiology of EFF as pertains to the presence of av's. Current recommendations for obliteration of av, the available techniques and the evidence to support current clinical practice are discussed. The possible cons of av obliteration are highlighted, while newer concepts and the need for future clinical trials are addressed.

Upper Limb Grafts for Hemodialysis Access

Arteriovenous (AV) grafts are required for hemodialysis access when options for native fistulas have been fully exhausted, where they continue to play an important role in hemodialysis patients, offering a better alternative to central vein catheters. When planning autogenous accesses using Doppler ultrasound, adequate arterial inflow and venous outflow must be consciously preserved for future access creation with grafts. Efforts to improve graft patency include changing graft configuration, graft biology and hemodynamics. Industry offers early cannulation grafts to reduce central catheter use and a bioengineered graft is undergoing clinical studies. Although the outcome of AV grafts is inferior to fistulas, grafts can provide long-term hemodialysis access that is a better alternative to central venous catheters. AV grafts have significant drawbacks, mainly poor patency, infection and cost but also have some advantages: early maturation, ease of creation and needling and widespread availability. The outcome of AV graft surgery is variable from center to center. The primary patency rate for AV grafts is 58% at 6 months and the secondary patency rate is 76% at 6 months and 55% at 18 months. There are centers of excellence that report a 1 year secondary patency rate of up to 91%. In this review of the use of AV grafts for hemodialysis access in the upper extremities, technical issues involved in planning the access and performing the surgery in its different configurations are discussed and the role of surveillance and maintenance with their attendant surgical and radiological interventions is described.

Risk Factors Associated with Arteriovenous Fistula Failure after First Radiologic Intervention

Purpose

Improving arteriovenous fistula (AVF) patency is an integral part of the care of hemodialysis patients, often requiring procedures such as percutaneous transluminal angioplasty (PTA). However, these interventions may fail to reduce AVF dysfunction and failure. The purpose of this study was to determine predictive factors for subsequent AVF failure post-PTA.

Methods

Data from 155 consecutive AVFs in 155 patients at a single institution who had undergone a first PTA and had at least 1 year of follow-up data were analyzed. Using survival analysis, we assessed primary and secondary patency, and identified predictive factors taking into account competing risks.

Results

Of the 155 patients, 52% required multiple subsequent PTAs; 32% of the AVFs were not in use prior to the first PTA. At first PTA, 83% had outflow vein stenosis (OVS), 26% had multiple stenoses and 43% of stenoses were longer than 2 cm. During follow-up, 1-, 2-, 3-year postintervention primary patency was 41%, 32%, 32% and secondary patency was 80%, 71% and 68%. AVFs with stenoses greater than 2 cm or OVS were at higher risk of requiring multiple PTAs (p = 0.04, 0.006). Factors associated with requiring a second PTA included stenosis greater than 2 cm (hazard ratio (HR) = 1.8, 95% confidence interval (CI) = 1.2-2.9), OVS (HR = 2.5, 95% CI = 1.1-5.4) and primary renal diagnosis of diabetes or renal vascular diseases (HR = 1.8, 95% CI = 1.1-2.9); after adjustments for competing risks, OVS and stenosis length remained associated with requiring subsequent PTAs.

Conclusions

The location and size of the AVF stenosis at first PTA appear to be consistent factors associated with worse postintervention primary patency.

Persistent Median Artery As A Cause Of Nonmaturing AV Fistula

A 68-year-old right handed male with End-Stage Renal Disease with a left radiocephalic fistula created 8 months ago was referred for the evaluation of a nonmaturing access. Patient had an arterial anastomosis lesion that underwent successful angioplasty. Diagnostic arteriogram of the AV access extremity revealed the presence of a short radial artery and dominant common interosseous artery manifesting as a persistent median artery in the distal forearm and was anastomosed to the fistula and then continues as the median-ulnar superficial arch in the palm. Balloon angioplasty of the common interosseous artery led to a complication when the distal 30 cm of the 0.018 guide wire fractured and had to be retrieved using a snare device. In addition to anticipating and treating the common complications of vascular access procedures, it is also important to be aware of the anomalies of the distal forearm arterial anatomy and perform a detailed arterial evaluation prior to creating the arterio-venous anastomosis.

Primary Intraoperative Transluminal Angioplasty: A New Approach to Reduce the Early Failure of Distal Arteriovenous Fistulas

Purpose

About 8 years ago, we approached an intraoperative transluminal angioplasty (ITA) performed during the arteriovenous fistula (AVF) creation, to treat arterial or venous stenosis diagnosed by a preliminary ultrasound examination. Objective of this study is to validate the efficacy of ITA.

Methods

Early failure (EF) and failure to mature (FTM) were evaluated in 69 AVFs with ITA created in 58 patients in the last 3 years. In the same period, 160 patients received 188 AVFs without ITA and were considered control group. Of the two groups, age, comorbid factors, sex, primary and secondary patency rate (PR) were also analysed.

Results

The two groups were homogeneous for gender and age (70.4 + 11.1 years of ITA group vs. 66.3 + 14.4, p = 0.059). The incidence of diabetes, heart disease and peripheral artery disease was higher in the ITA group (43% vs. 17%, p<0.0001, 35% vs. 6%, p<0.0001 and 56% vs. 15%, p<0.0001, respectively). EF and FTM occurred in seven and eight cases in the ITA group and in 15 and 13 cases in the controls, respectively. Total failure occurred in 24% of ITA group and 14% of the controls (p = 0.2). The primary PR at 6, 12 and 24 months was 78%, 72% and 59% for ITA group and 85%, 78% and 78 % for control group (p<0.01). The secondary PR at 6, 12 and 24 months was 91%, 86% and 80% for ITA group and 95%, 95% and 92% for the controls (p<0.01).

Conclusions

Our ITA approach has allowed satisfactory results in patients at a high risk of AVF failure.

Accessory veins in nonmaturing autogenous arteriovenous fistulae: analysis of anatomic features and impact on fistula maturation

The appropriate management of nonmaturing arteriovenous (AV) fistulae continues to be a controversial issue. While coil embolization of accessory side-branch veins can be performed to encourage maturation of nonmaturing AV fistulae, the true efficacy and optimal patient population are not well understood. Fistulagrams performed on nonmaturing AV fistulae were retrospectively reviewed in 145 patients (86 males, median age 63 years) for the presence of accessory veins. Fistula and accessory vein measurements were obtained, as were rates of eventual fistula maturation after accessory vein coil embolization. Of 145 nonmaturing fistulae, 49 (34%) had a stenosis without any accessory veins, 76 (52%) had a stenosis and one or more accessory veins, and 20 (14%) had an accessory vein without concurrent stenosis. Eighteen AV fistulae had one or more accessory veins without coexisting stenosis. Nine fistulae had a caliber decrease immediately downstream from the accessory vein. Coil embolization of dominant accessory veins with a caliber decrease immediately downstream (n = 6) resulted in a 100% eventual fistula maturation rate versus 67% for fistulae without this configuration (n = 6, p = 0.15). Accessory vein size was not correlated with maturation rates (p = 0.51). The majority of nonmaturing fistulae with accessory veins had a coexisting stenosis. Higher maturation rates may result with selected anatomic parameters, although additional studies with more robust sample sizes are needed prior to definitive conclusions.

Effectiveness of collateral vein embolization for salvage of immature native arteriovenous fistulas

PURPOSE

To investigate the value of collateral vein embolization (CVE) as a salvage treatment for nonmaturing native arteriovenous fistulae (AVFs) in patients requiring hemodialysis.

MATERIALS AND METHODS

A total of 49 patients undergoing CVE (N = 65) for immature native AVFs at a single institution were reviewed. The study included 42 patients treated by 56 embolizations. Average fistula age at time of intervention was 18.2 weeks. Each patient underwent angiographic evaluation for fistula immaturity, with clinical success defined by initiation of single-session hemodialysis through the native fistula.

RESULTS

Fistula maturity was achieved in 32 of 42 patients (76.2%). No major complications occurred. Average time from CVE to fistula maturity was 38.4 days. Angioplasty done with CVE was found in a statistically higher percentage of patients with fistula success versus failure (31.3% vs 8.3%; P = .039). Radiocephalic fistulae were seen in a higher percentage of fistula failures compared with successes, but the results were not statistically significant (83.3% vs 59.4%; P = .054). Thirty-four patients underwent CVE without angioplasty, which resulted in successful fistula maturation in 22 cases (64.7%). Radiocephalic fistulae were again seen in a higher percentage of fistula failures compared with successes, but the findings did not meet statistical significance (81.8% vs 54.5%; P = .052).

CONCLUSIONS

Coil embolization of competing collateral vessels as a salvage treatment for nonfunctioning autologous AVFs is a viable treatment option in the majority of patients. Patients with radiocephalic fistulae may be at higher risk for primary fistula failure, but the present data are inconclusive.

Mechanical enhancement of AVF maturation

A native arteriovenous fistula (AVF) should be systematically evaluated at 4 to 6 weeks after creation. Any clinical indications of nonmaturation should be promptly followed up and confirmed by detailed duplex ultrasonography looking for a deep vein or inadequate access flow due to stenoses. Once vein depth has been ruled out, a significant stenosis is invariably identified and should therefore be operated on or dilated. Predilation angiography should be performed preferably through the brachial artery. Arterial lesions are frequent causes of nonmaturation of forearm AVFs and should therefore be dilated. The best results are obtained when the juxta-anastomotic vein and the feeding artery are dilated with 6 and 4 mm dilation balloons, respectively. Our opinion is that there is no or only the very rare indication for ligation or embolization of collaterals. Rupture of the weak venous or arterial wall is common (15% of cases), the majority of which can be managed with prolonged balloon tamponade. Nonmaturing AVFs are ideally needled only 7 to 14 days after successful dilation to allow hematomas caused by cannulation and local anesthesia to resorb. Including initial failures, 1-year primary and secondary patency rates reported by interventional radiologists range from 34% to 39% and 68% to 79%, respectively. Results after dilation of diseased radial arteries feeding normal veins are even better, with primary patency rates ranging for 65% to 83%, and secondary patency rates of over 90%. Using an aggressive and multidisciplinary treatment strategy, nonmaturing dialysis fistulas can be identified, evaluated and salvaged with angioplasty.

Fistula eligibility: a work in progress

Effective hemodialysis requires a reliable vascular access. Clinical practice guidelines strongly recommend the fistula as the preferred option followed by arteriovenous (AV) grafts, with central venous catheters being least preferred. Recently, there has been a growing awareness of the limitations of the fistula, its high rate of primary failure and that a fistula may not be appropriate for all patients initiating or on hemodialysis. However, determinates for fistula eligibility have not been clearly defined. The creation and use of a fistula requires the complex integration of patient, biological, and surgical factors, none of which can be easily predicted or planned. There have been several successful initiatives over the last decade addressing patient suitability for AV access, but none have validated defined criteria for fistula eligibility. We discuss these initiatives by addressing: 1) process of care, 2) radiological and nonradiological tests and procedures, and 3) alternative surgical approaches. Careful clinical judgment, appropriate vascular access assessment and placement, and an individualized approach to the risks and benefits will optimize patient health outcomes while minimizing prolonged catheter dependence among hemodialysis patients.