Improved cumulative survival in fistulas requiring surgical interventions to promote fistula maturation compared with endovascular interventions

Rejoining Veins for Forced Maturation of Small-Caliber Arteriovenous Fistula

BACKGROUND

To evaluate the efficacy of rejoining mainstream and accessory veins for forced maturation of autogenous arteriovenous fistula (AVF).

METHODS

Twenty-three patients who underwent forced maturation through vein rejoining between January 2018 and September 2022 were included. In cases where AVF maturation failure due to the presence of accessory veins, rejoining was primarily considered when distinguishing the main branch becomes challenging. This difficulty typically occurs when the sizes of the 2 vessels are nearly equal and the combined diameters of these veins exceed 6 mm.

RESULTS

The mean age and follow-up duration were 57.39 ± 16.22 years and 965.65 ± 573.42 days, respectively. Rejoining of both arterial and venous cannulation sites was performed in 11 patients (47.8%), and rejoining of only the venous cannulation site or only the arterial cannulation site was performed in 11 patients (47.8%) and 1 patient (4.3%), respectively. The mean vein size was 0.35 ± 0.06 cm before rejoining and 0.69 ± 0.07 cm after surgery, indicating a significant increase in size (P < 0.01), whereas the flow did not change significantly following rejoining surgery. Maturation and cannulation success was 100%. The 1-year primary patency rate after surgery was 82.0%. During the follow-up period, 34.8% of the patients required additional percutaneous transluminal angioplasty to maintain patency, and 2 patients (11.8%) had stenosis in the rejoined section.

CONCLUSIONS

Rejoining surgery is an effective method for achieving AVF maturation in patients with accessory veins when identification of the mainstream vein is difficult, and this method may be considered when achieving maturation by sacrificing 1 vein is expected to be challenging.

Tongue patch angioplasty for small-caliber vein segments directly connected to juxta-anastomotic stenosis

This study introduces a surgical method to increase the size of small vessels in patients with juxta-anastomosis stenosis (JAS) requiring full-length dissection. The small-caliber segment that is adjacent to JAS is usually expanded using balloon angioplasty or surgically resected. After resection, if the cannulation site is sufficient, only the arterial anastomosis is moved proximally; otherwise, it is replaced with a prosthetic graft. Herein, we describe the cases of two 60- and 34-year-old men with left brachio-basilar and left radiocephalic fistulas, respectively. The first and second patients needed transposition and superficialization, respectively, both of which required full-length vessel dissection. Both patients developed JAS with a long, small-caliber segment, leaving no space for arterial needle cannulation. A tongue patch with a graft on the bottom and a native vein on the top was used to resolve the JAS and make the native vein the needle cannulation site. In our cases, this method was effective for more than 2 years without adverse events in the particular surgical area. Although this method had a complicated indication, it could help ensure a sufficiently long area of the native vein for cannulation.

The RADAR technique in reconstruction of failed autologous arteriovenous fistulas due to juxta-anastomotic stenosis is equivalent to that with traditional surgery in maintenance hemodialysis patients

OBJECTIVE

Autologous arteriovenous fistula (AVF) is recommended as superior vascular access for hemodialysis but has a high rate of failure, and juxta-anastomotic stenosis (JAS) is one of the predominant causes of fistula failure. The aim of this study was to compare the primary patency in reconstruction of failed AVFs due to JAS between the radial artery deviation and reimplantation (RADAR) technique and traditional surgery (end-vein to side-artery neo-anastomosis) in maintenance hemodialysis (MHD) patients.

METHODS

A total of 1215 MHD patients with failed AVF were enrolled in this retrospective cohort study, and 614 patients with failed AVF received surgical intervention. Among these surgical interventions, 417 patients experienced AVF failure due to JAS. Finally, 25 patients who received the RADAR technique were enrolled. Controls of 50 patients received traditional surgery were randomly selected matched by age and sex. Clinical data such as age, sex, comorbidities, and blood biochemical indices were collected. Kaplan-Meier survival curves and Cox proportional hazards analyses were used to explore the difference between the RADAR group and the traditional group in reconstruction of failed AVFs.

RESULTS

The RADAR group and the traditional group shared common baseline characteristics. The primary patencies of the reconstructed AVFs were 88.8%, 79.0%, 72.2%, 57.4%, and 38.3% at 12, 24, 36, 48, and 60 months among the 75 patients, respectively. Kaplan-Meier survival curve analysis demonstrated similar primary patencies in the two groups (log-rank test, p = 0.73). Compared with the traditional group, the RADAR group had no difference in predicting AVF failure after adjusting for potential confounders, with an HR of 0.92 (95% CI, 0.18-4.63).

CONCLUSIONS

The primary patency of the RADAR technique and the traditional surgery in the reconstruction of failed AVFs due to JAS is almost equal in 5 years.

Differential hemodynamics between arteriovenous fistulas with or without intervention before successful use

A significant number of arteriovenous fistulas (AVFs) fail to maturate for dialysis. Although interventions promote maturation, functional primary patency loss is higher for AVFs with interventions (assisted maturation) than AVFs without interventions (un-assisted maturation). Although blood flow-associated hemodynamics have long been proposed to affect AVF remodeling, the optimal hemodynamic parameters for un-assisted maturation are unclear. Additionally, AVF maturation progress is generally not investigated until 6 weeks after AVF creation, and the examination is focused on the AVF's venous limb. In this exploratory study, patients (n = 6) underwent magnetic resonance imaging (MRI) at 1 day, 6 weeks, and 6 months after AVF creation surgery. Before successful use for hemodialysis, three AVFs required intervention and three did not. MRI of the AVFs were used to calculate lumen cross-sectional area (CSA) and perform computational fluid dynamics (CFD) to analyze hemodynamics, including velocity, wall shear stress (WSS), and vorticity. For the venous limb, the no-intervention group and intervention group had similar pre-surgery vein diameter and 1-day post-surgery venous CSA. However, the no-intervention group had statistically larger 1-day venous velocity (0.97 ± 0.67 m/s; mean ± SD), WSS (333 ± 336 dyne/cm2) and vorticity (1709 ± 1290 1/s) than the intervention group (velocity = 0.23 ± 0.10 m/s; WSS = 49 ± 40 dyne/cm2; vorticity = 493.1 ± 227 1/s) (P < 0.05). At 6 months, the no-intervention group had statistically larger venous CSA (43.5 ± 27.4 mm2) than the intervention group (15.1 ± 6.2 mm2) (P < 0.05). Regarding the arterial limb, no-intervention AVF arteries also had statistically larger 1-day velocity (1.17 ± 1.0 m/s), WSS (340 ± 423 dyne/cm2), vorticity (1787 ± 1694 1/s), and 6-month CSA (22.6 ± 22.7 mm2) than the intervention group (velocity = 0.64 ± 0.36 m/s; WSS = 104 ± 116 dyne/cm2, P < 0.05; vorticity = 867 ± 4551/s; CSA = 10.7 ± 6.0 mm2, P < 0.05). Larger venous velocity, WSS, and vorticity immediately after AVF creation surgery may be important for later lumen enlargement and AVF maturation, with the potential to be used as a tool to help diagnose poor AVF maturation earlier. However, future studies using a larger cohort are needed to validate this finding and determine cut off values, if any.

A novel technique using long segment patch angioplasty maturation to increase the maturation rate of arteriovenous fistulas

OBJECTIVE

Given the superior patency of arteriovenous fistulas (AVFs) and the decreased risk of infection compared with arteriovenous grafts, the Kidney Disease Outcomes Quality Initiative guidelines have recommended the fistula-first approach. However, ∼20% to 60% of all fistulas will fail to mature. We have described our experience with a novel technique using bovine pericardial patch angioplasty to increase the rate of AVF maturation.

METHODS

We used 2-cm × 9-cm-long or 2.5-cm × 15-cm-long segment pericardial patch angioplasty to assist in the maturation of AVFs. A single-center, retrospective cohort study was conducted of all patients who had undergone patch angioplasty maturation (PAM) for AVFs that had failed to mature. The outcomes of interest were maturation status and patency, censored by the death and last known follow-up dates.

RESULTS

From March 2007 to October 2019, 139 patients had undergone PAM. Follow-up data were available for 137 of the 139 patients (98.6%), with 126 AVFs (92.0%) progressing to maturation. Of the 126 patients with AVFs that had progressed to maturity, the previous hemodialysis (HD) method was known for 88 patients (69.8%). Of these 88 patients, 70 (79.5%) had previously been receiving HD via an HD catheter. Using a Kaplan-Meier estimator censored for death and loss to follow-up, the assisted primary patency rates at 1, 2, and 3 years were 87.3%, 78.1%, and 68.0%, respectively. Of the 137 patients, 69 (54.8%) had required no additional interventions after patch angioplasty. The complications requiring intervention were stenosis (n = 45; 32.8%), thrombosis (n = 10; 7.3%), infection (n = 3; 2.2%), steal syndrome (n = 3; 2.2%), noninfected wound complications (n = 1; 0.8%), and pseudoaneurysm (n = 1; 0.8%). The average interval to intervention after patch angioplasty was 4.56 months.

CONCLUSIONS

Long-segment bovine pericardial PAM can be performed safely to treat nonmaturing AVFs, with a 92.0% successful maturation rate and patency rates comparable to those for AVFs. PAM should be a consideration for patients with nonmaturing AVFs.

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.

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.

Clinical outcomes following the surgery of new autologous arteriovenous fistulas proximal to the failed ones in end-stage renal disease patients: a retrospective cohort study

Background: Most prior studies have explored surgery for the treatment of failed autologous arteriovenous fistulas (AVFs) with limited follow-up times and a lack of end point mortality. Accordingly, we conducted a retrospective cohort study to evaluate the clinical outcomes of the surgery of new AVF proximal to the failed forearm AVF.

Methods: In this study, 538 end-stage renal disease patients (group A, 418 with primary AVF; and group B, 120 with failed AVF) were consecutively enrolled between January 2013 and June 2016, with a median follow-up time of 41 months. Primary and secondary patency, all-cause mortality, and risk factors associated with AVF failure were explored by the Kaplan–Meier method or Cox proportional hazards model.

Results: In group A (n = 418), the primary and secondary patencies of AVF were 85.6% vs. 96.8%, 79.7% vs. 95.0%, 75.1% vs.93.9%, 73.2% vs. 93.6% and 73.2% vs. 93.6% at 12, 24, 36, 48 and 60 months, respectively. The primary patencies of AVF in group B were 95.0%, 91.7%, 89.2%, 88.3% and 88.3% at 12, 24, 36, 48 and 60 months, respectively. After adjusting for potential confounders, age, angiotensin-converting inhibitors or angiotensin-receptor blockers (anti-RAAS) drugs and D-dimer were independent predictors of AVF failure. However, there were no differences between functional and failed AVF regarding all-cause mortality.

Conclusions: The study revealed that the primary and secondary patiencies of the surgery of new AVF proximal to the failed ones were ideal operations to restore failed forearm AVF.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Definitions and End Points for Interventional Studies for Arteriovenous Dialysis Access

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

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.

Changes in the Profile of Endovascular Procedures Performed in Freestanding Dialysis Access Centers over 15 Years

BACKGROUND AND OBJECTIVES

Marked changes occurred in the vascular access profile of patients receiving hemodialysis in the United States over the 15-year period of 2001-2015. This study was undertaken to evaluate how these changes have affected dialysis access maintenance and salvage procedures performed in freestanding dialysis access centers and to examine the effectiveness, efficiency, and safety of these procedures in this setting.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data were collected from freestanding, dedicated dialysis access centers operating under a common system of management. Data were available on 689,676 dialysis access procedures. Data relating to case mix, procedure outcome, procedural time, and intraprocedural and immediate postprocedural complications were analyzed.

RESULTS

The arteriovenous procedure profile changed from one characterized by approximately equal numbers of angioplasties and thrombectomies performed on arteriovenous grafts (AVGs) to one characterized primarily by angioplasties performed on arteriovenous fistulas. The percentage of angioplasties performed throughout the study was significantly greater than thrombectomies, with a mean of 67.9% versus 32.1% (P<0.001). Interventional procedures did not decrease with increasing arteriovenous fistula utilization in prevalent patients receiving dialysis. The incidence roughly paralleled the increasing prevalence of this type of access. A decreasing percentage of AVG utilization resulted in a progressive, roughly parallel, but disproportionately higher, decrease in the percentage of AVG procedures (P<0.001). A progressive improvement in procedure outcomes and a decrease in complication rates and procedure times were observed (P<0.001 for each). A progressive decrease in tunneled dialysis catheter placement was also observed.

CONCLUSIONS

The procedure profile treated in freestanding, dedicated dialysis access centers changed significantly over 15 years, reflecting the changes that have occurred in the vascular access profile of the dialysis population.

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.

Very high-dose cholecalciferol and arteriovenous fistula maturation in ESRD: a randomized, double-blind, placebo-controlled pilot study

PURPOSE

While vitamin D is critical for optimal skeletal health, it also appears to play a significant role in vascular homeostasis. This pilot study compared arteriovenous (AV) access outcomes following cholecalciferol supplementation compared to placebo in end-stage renal disease patients preparing to undergo AV access creation.

METHODS

A total of 52 adult hemodialysis patients preparing for arteriovenous fistula (AVF) creation were randomized to receive perioperative high-dose cholecalciferol versus placebo in this double-blind, randomized, placebo-controlled pilot study. The primary outcome was mean response to high-dose oral cholecalciferol versus placebo, and secondary outcome AV access maturation at 6 months. Logistic regression was used to assess the association between AV access maturation and baseline, posttreatment and overall change in vitamin D concentration.

RESULTS

A total of 45% of cholecalciferol-treated and 54% of placebo-treated patients were successfully using their AVF or arteriovenous graft (AVG) at 6 months (p=0.8). Baseline serum concentrations of 25(OH)D and 1,25(OH)2D did not differ between those who experienced AVF or AVG maturation and those who did not (p=0.22 and 0.59, respectively). Similarly, there was no relationship between AVF or AVG maturation and posttreatment serum 25(OH)D and 1,25(OH)2D concentration (p=0.24 and 0.51, respectively).

CONCLUSIONS

Perioperative high-dose vitamin D3 therapy does correct 25(OH)D level but does not appear to have an association with AV access maturation rates. Future research may include extended preoperative vitamin D3 therapy in a larger population or in certain subpopulations at high risk for AVF failure.

Natural history of venous morphologic changes in dialysis access stenosis

PURPOSE

Venous stenosis secondary to neointimal hyperplasia is a major etiology of early arteriovenous fistula (AVF) failure. The natural history of AVF failure is likely influenced by progressive vascular insults to the vein prior to and after AVF creation. The main objectives of this study were to (1) provide a histologic and morphometric description of non-chronic kidney disease (CKD), upper extremity vein specimens and (2) perform a morphometric analysis to study venous histology from non-CKD upper extremity veins, veins collected at the time of new vascular access surgery and veins collected from failed stenotic AVFs.

METHODS

Vein samples from 11 non-CKD deceased donors, 29 subjects receiving new vascular access creation and 20 subjects with stenotic failed AVFs were collected for histologic and morphometric analysis.

RESULTS

The mean values of average intima/media thickness ± S.E. from veins collected from non-CKD subjects, subjects receiving new vascular access and subjects with stenotic AVFs were 0.16±0.02, 0.43±0.07 and 3.84±0.55, respectively (p<0.0001). Among donor, non-CKD, vein samples, only diabetes (p=0.0007) was associated with increased average intima/media thickness.

CONCLUSIONS

Our results demonstrate a progressively increasing venous neointimal hyperplasia development from the non-CKD period through the period of AVF creation and failure. Vascular injuries from complications of progressive CKD prior to access placement and vascular injuries after vascular access placement may play important roles in these progressive vascular changes, and need to be further elucidated.