Hemodialysis arteriovenous fistula patency revisited: results of a prospective, multicenter initiative

Distal Forearm Arteriovenous Fistula Maturation in Diabetic Hemodialysis Patients

PURPOSE

Atherosclerotic disease of the forearm arteries can impede the maturation of distal fistulas in diabetic patients. The goal of this study was to look at the maturity of diabetic hemodialysis patients' distal forearm (radiocephalic snuffbox or distal forearm) arteriovenous fistulas.

MATERIALS AND METHODS

Patients with chronic renal failure who were candidates for distal forearm radiocephalic arteriovenous fistula implantation were evaluated in this cross-sectional study. Patients' demographic details, underlying disorders, laboratory measurements, vital signs, and information on their surgery were all noted. Patients were checked for fistula development 1 week, 1 month, 2 months, and then monthly until 6 months after surgery. Arteriovenous fistula maturation characterized by optimal blood flow, vessel dilation, and structural adaptations.

RESULTS

Among 343 patients (56% male, 44% female, mean age: 57.32 ± 12.48 years), hypertension prevailed (81.9%), followed by hyperlipidemia (42.3%) and coronary artery disease history (25.9%). AVFs achieved 58.3% maturation in 64.98 ± 11.05 days; higher BP during creation correlated with successful maturation (17.02 ± 1.46 mmHg vs 13.90 ± 1.93 mmHg, P < .05). No significant statistical difference found in distal forearm arteriovenous fistula maturation between males (57.8%) and females (58.9%) (P > .005). However, 41.7% of AVFs failed in 18.83 ± 17.89 days. Failed AVFs exhibited lower BP during operation and failure (11.75 ± 1.86 mmHg). Kaplan-Meier analysis depicted maturation probabilities over 90 days post-surgery.

CONCLUSION

Diabetes and patient sex did not affect the maturation time of distal forearm AVFs in hemodialysis patients. Increased blood pressure during and after surgery correlated with shorter maturation time.

To evaluate the complication and patency rate of superficial femoral vein transposition in tertiary care center

INTRODUCTION

When all access options in the upper extremity have been exhausted, an autologous access can be created in lower extremity. The purpose of this study is to report our experience with superficial femoral vein transposition (SFVT) results in terms of postoperative complication and patency rate.

MATERIALS AND METHODS

In the time period from January 1, 2019 to April 30, 2021, thirty-five cases of SFVT performed at our large tertiary care center Sindh Institute of Urology and Transplantation (SIUT). All patients had exhausted upper arm veins or had central vein obstructions. Medical records of all patients were traced, patients were interviewed using a standard proforma and evaluated the current AVF function in the OPD clinic or by telephone calls. Data including demographics and postoperative complications were collected.

RESULTS

Thirty-nine cases of SFVT performed at our institute. Three were immediately lost to follow up so they were excluded from the study. Mean patient age was 30 ± 13.4 years. Most of our patients were females (57%) and 15 males (43%) with an average age of 29.05 years. The most common underlying renal diseasewas unknown in 16 (45%).Thirty-five patients included in the analysis; out of which primary failure observed in 4 patients, three patients were expired before fistula maturation and 3 were expired before 6 months. The remaining 25 fistulas patency rates were estimated. No any patient died due to fistulas related complication; patients died due to their primary disease.

CONCLUSION

Our study shows that with appropriate patient selection, SFVT have low infection rates and patency that is comparable with other access types.

Doppler ultrasound surveillance of recently formed haemodialysis arteriovenous fistula: the SONAR observational cohort study

Background

Arteriovenous fistulas are considered the best option for haemodialysis provision, but as many as 30% fail to mature or suffer early failure.

Objective

To assess the feasibility of performing a randomised controlled trial that examines whether, by informing early and effective salvage intervention of fistulas that would otherwise fail, Doppler ultrasound surveillance of developing arteriovenous fistulas improves longer-term arteriovenous fistula patency.

Design

A prospective multicentre observational cohort study (the 'SONAR' study).

Setting

Seventeen haemodialysis centres in the UK.

Participants

Consenting adults with end-stage renal disease who were scheduled to have an arteriovenous fistula created.

Intervention

Participants underwent Doppler ultrasound surveillance of their arteriovenous fistulas at 2, 4, 6 and 10 weeks after creation, with clinical teams blinded to the ultrasound surveillance findings.

Main outcome measures

Fistula maturation at week 10 defined according to ultrasound surveillance parameters of representative venous diameter and blood flow (wrist arteriovenous fistulas: ≥ 4 mm and > 400 ml/minute; elbow arteriovenous fistulas: ≥ 5 mm and > 500 ml/minute). Mixed multivariable logistic regression modelling of the early ultrasound scan data was used to predict arteriovenous fistula non-maturation by 10 weeks and fistula failure at 6 months.

Results

A total of 333 arteriovenous fistulas were created during the study window (47.7% wrist, 52.3% elbow). By 2 weeks, 37 (11.1%) arteriovenous fistulas had failed (thrombosed), but by 10 weeks, 219 of 333 (65.8%) of created arteriovenous fistulas had reached maturity (60.4% wrist, 67.2% elbow). Persistently lower flow rates and venous diameters were observed in those fistulas that did not mature. Models for arteriovenous fistulas' non-maturation could be optimally constructed using the week 4 scan data, with fistula venous diameter and flow rate the most significant variables in explaining wrist fistula maturity failure (positive predictive value 60.6%, 95% confidence interval 43.9% to 77.3%), whereas resistance index and flow rate were most significant for elbow arteriovenous fistulas (positive predictive value 66.7%, 95% confidence interval 48.9% to 84.4%). In contrast to non-maturation, both models predicted fistula maturation much more reliably [negative predictive values of 95.4% (95% confidence interval 91.0% to 99.8%) and 95.6% (95% confidence interval 91.8% to 99.4%) for wrist and elbow, respectively]. Additional follow-up and modelling on a subset (n = 192) of the original SONAR cohort (the SONAR-12M study) revealed the rates of primary, assisted primary and secondary patency arteriovenous fistulas at 6 months were 76.5, 80.7 and 83.3, respectively. Fistula vein size, flow rate and resistance index could identify primary patency failure at 6 months, with similar predictive power as for 10-week arteriovenous fistula maturity failure, but with wide confidence intervals for wrist (positive predictive value 72.7%, 95% confidence interval 46.4% to 99.0%) and elbow (positive predictive value 57.1%, 95% confidence interval 20.5% to 93.8%). These models, moreover, performed poorly at identifying assisted primary and secondary patency failure, likely because a subset of those arteriovenous fistulas identified on ultrasound surveillance as at risk underwent subsequent successful salvage intervention without recourse to early ultrasound data.

Conclusions

Although early ultrasound can predict fistula maturation and longer-term patency very effectively, it was only moderately good at identifying those fistulas likely to remain immature or to fail within 6 months. Allied to the better- than-expected fistula patency rates achieved (that are further improved by successful salvage), we estimate that a randomised controlled trial comparing early ultrasound-guided intervention against standard care would require at least 1300 fistulas and would achieve only minimal patient benefit.

Trial Registration

This trial is registered as ISRCTN36033877 and ISRCTN17399438.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR135572) and is published in full in Health Technology Assessment; Vol. 28, No. 24. See the NIHR Funding and Awards website for further award information.

Assessing Time to Removal of Tunneled Dialysis Catheters after Arteriovenous Access Creation

BACKGROUND

Tunneled dialysis catheters (TDCs) are a temporary bridge until definitive arteriovenous (AV) access is established. Our objective was to evaluate the time to TDC removal in patients who underwent AV access creations with TDCs already in place.

METHODS

A single-center analysis of all AV access creations in patients with TDCs was performed (2014-2020). Primary outcome was time to TDC removal after access creation.

RESULTS

There were 364 AV access creations with TDCs in place. The average age was 58 years, 44% of patients were female, and 64% were Black. The median time to TDC removal was 113 days (range, 22-931 days) with 71.4% having a TDC >90 days after access creation. Patients with TDC >90 days were often older (60 vs. 54.7), had hypertension (98.1% vs. 93.3%), were diabetic (65.4% vs. 47.1%), and had longer average time to maturation (107.1 vs. 55.4 days, P < 0.001) and first access (114 vs. 59.4 days, P < 0.001). Multivariable analysis showed that older age was associated with prolonged TDC placement (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.05, P = 0.005) and prosthetic graft use was associated with shorter TDC indwelling time (OR 0.09, 95% CI 0.04-0.23, P ≤ 0.001). Kaplan-Meier analysis showed that 87% of TDCs were removed at 1 year.

CONCLUSIONS

The majority of patients with TDCs who underwent AV access creation had prolonged TDC placement. Prosthetic graft use was associated with shorter catheter times. Close follow-up after access placement, improving maturation times, and access type selection should be considered to shortened TDC times.

Long-term outcomes following thrombolysis of arteriovenous grafts

BACKGROUND

Thrombolysis for arteriovenous grafts (AVG) yields high technical success rates, however, long-term outcomes are unclear. We conducted a multicenter retrospective cohort study to analyze 5-year patency rates following AVG thrombolysis.

METHODS

All patients who underwent AVG thrombolysis between 2005 and 2015 at three academic hospitals were included. Prospectively maintained institutional nephrology and radiology databases were used to record demographic, clinical, and AVG characteristics. The primary outcome was primary patency, defined as AVG access survival without re-intervention including angioplasty ± stent with/without re-thrombolysis. Secondary outcomes were assisted primary patency and cumulative patency, defined as AVG access survival until re-thrombosis requiring re-thrombolysis or abandonment, respectively. Technical success was defined as restoration of flow with <30% residual stenosis. Patients were followed until 2017. Patency rates were assessed using Kaplan-Meier survival analysis and Cox proportional hazards were calculated to determine associations between covariates and patency loss.

RESULTS

Seventy-four patients underwent AVG thrombolysis during the study period with a median follow-up period of 21.4 (IQR 8.3-42.8) months. The average age was 58.6 years with a high rate of comorbidities, including hypertension (82.4%) and diabetes (54.1%). Thrombolysis technical success was 96%. There were 147 re-interventions in 46 patients, of which 98 were re-thrombolysis (mean re-intervention rate of 1.27/patient/year). Primary patency at 1, 3, and 5 years were 43.2%, 20.2%, and 7.7%. Assisted primary patency at 1, 3, and 5 years were 47.5%, 20.2%, and 7.7%. Cumulative patency at 1, 3, and 5 years were 75.0%, 38.8%, and 22.6%. Cox proportional hazards analysis demonstrated no associations between demographic, clinical, and procedural characteristics and patency rates.

CONCLUSIONS

Despite a high technical success rate, thrombolysis for AVG dysfunction is associated with poor long-term patency. Future studies are needed to determine risk factors for re-thrombosis to identify patients who will benefit from AVG thrombolysis in the long-term.

A systematic review of prediction models on arteriovenous fistula: Risk scores and machine learning approaches

OBJECTIVE

Failure-to-mature and early stenosis remains the Achille's heel of hemodialysis arteriovenous fistula (AVF) creation. The maturation and patency of an AVF can be influenced by a variety of demographic, comorbidity, and anatomical factors. This study aims to review the prediction models of AVF maturation and patency with various risk scores and machine learning models.

DATA SOURCES AND REVIEW METHODS

Literature search was performed on PubMed, Scopus, and Embase to identify eligible articles. The quality of the studies was assessed using the Prediction model Risk Of Bias ASsessment (PROBAST) Tool. The performance (discrimination and calibration) of the included studies were extracted.

RESULTS

Fourteen studies (seven studies used risk score approaches; seven studies used machine learning approaches) were included in the review. Among them, 12 studies were rated as high or unclear "risk of bias." Six studies were rated as high concern or unclear for "applicability." C-statistics (Model discrimination metric) was reported in five studies using risk score approach (0.70-0.886) and three utilized machine learning methods (0.80-0.85). Model calibration was reported in three studies. Failure-to-mature risk score developed by one of the studies has been externally validated in three different patient populations, however the model discrimination degraded significantly (C-statistics: 0.519-0.53).

CONCLUSION

The performance of existing predictive models for AVF maturation/patency is underreported. They showed satisfactory performance in their own study population. However, there was high risk of bias in methodology used to build some of the models. The reviewed models also lack external validation or had reduced performance in external cohort.

Early Ultrasound Surveillance of Newly-Created Hemodialysis Arteriovenous Fistula

Introduction

We assess if ultrasound surveillance of newly-created arteriovenous fistulas (AVFs) can predict nonmaturation sufficiently reliably to justify randomized controlled trial (RCT) evaluation of ultrasound-directed salvage intervention.

Methods

Consenting adults underwent blinded fortnightly ultrasound scanning of their AVF after creation, with scan characteristics that predicted AVF nonmaturation identified by logistic regression modeling.

Results

Of 333 AVFs created, 65.8% matured by 10 weeks. Serial scanning revealed that maturation occurred rapidly, whereas consistently lower fistula flow rates and venous diameters were observed in those that did not mature. Wrist and elbow AVF nonmaturation could be optimally modeled from week 4 ultrasound parameters alone, but with only moderate positive predictive values (PPVs) (wrist, 60.6% [95% confidence interval, CI: 43.9-77.3]; elbow, 66.7% [48.9-84.4]). Moreover, 40 (70.2%) of the 57 AVFs that thrombosed by week 10 had already failed by the week 4 scan, thus limiting the potential of salvage procedures initiated by that scan's findings to alter overall maturation rates. Modeling of the early ultrasound characteristics could also predict primary patency failure at 6 months; however, that model performed poorly at predicting assisted primary failure (those AVFs that failed despite a salvage attempt), partly because patency of at-risk AVFs was maintained by successful salvage performed without recourse to the early scan data.

Conclusion

Early ultrasound surveillance may predict fistula maturation, but is likely, at best, to result in only very modest improvements in fistula patency. Power calculations suggest that an impractically large number of participants (>1700) would be required for formal RCT evaluation.

Salvage of brachiocephalic aneurysmatic fistulas, using ePTFE graft with a minimally invasive approach

BACKGROUND

In this study, we evaluated our surgical approach in requiring surgical treatment of brachiocephalic arteriovenous fistula (AVF) aneurysms for salvage of AVF.

METHODS

Between 2012 and 2022, 20 patients (16 men, 4 women; mean age 54.5 years) who were surgically treated for a brachiocephalic AVF aneurysm in our Cardiovascular Surgery Clinic were evaluated retrospectively. These 20 patients were operated on for aneurysm thrombosis and fistula failure in 16 patients, sudden rupture and severe bleeding in 3 patients, cosmetic reasons, and anxiety in 1 patient.

RESULTS

These aneurysms were ligated and divided from distal and proximal cephalic veins. Then, a 6 mm dialysis graft was interposed between the well-developed cephalic vein distal and proximal to the aneurysm with small skin incisions. All patients were taken to dialysis via this dialysis graft 24 h after the procedure without any problem. All patients were discharged after dialysis. After surgery, no catheterization or any other additional procedure was required for hemodialysis. No complications, such as infection, hematoma, neurological damage, or ischemia, were observed after the surgical procedure. The mean postoperative follow-up was 12 months.

CONCLUSION

In brachiocephalic AVF aneurysms requiring surgical treatment, hemodialysis can be continued with a graft placed in the same arm in this technique.

Effectiveness of a native vein arteriovenous fistula tracking system

OBJECTIVE

This study aims to evaluate the effectiveness of a tracking program on the functional maturation rate of arteriovenous fistula (AVF).

METHODS

Two major clinical outcomes (commencement of cannulation and functional maturation) of created AVFs were compared between two cohorts. (i) Cohort 1: historical cohort; (ii) Cohort 2: AVFs created after implementation of the tracking project. Multivariable Cox regression models were used to assess the association between cohort allocation and the two major clinical outcomes.

RESULTS

Data of 114 and 141 patients were analyzed respectively from Cohorts 1 (historical data) and 2 (with AVF tracking). After adjustment of covariates in the multivariable analysis, the AVFs created in Cohort 2 were more likely to be cannulated earlier (adjusted HR: 2.82; 95% CI: 1.97-4.05; p < 0.001), compared to those in Cohort 1. Similarly, the AVFs of Cohort 2 patients had significantly higher probability of functional maturation (adjusted HR: 1.81; 95% CI: 1.31-2.48; p < 0.001) than fistulas in Cohort 1. Cannulation was commenced for half of the AVFs by 4.1 months post-creation in the historical cohort (Cohort 1), whereas in the post-tracking cohort, 50% of the AVFs were cannulated by 2.3 months after creation (p < 0.001). It took 5.5 and 4.3 months for 50% of the AVFs created in Cohort 1 and Cohort 2 patients to achieve catheter-free functional maturation, respectively (p = 0.06).

CONCLUSION

An AVF tracking program with maturation target for the access surgeons, together with a standardized tracking, feedback, and clinical strategy adjustment system is able to improve the AVF functional maturation rate.

Fully no-touch technique without inflating the cephalic vein increase the patency rate of arteriovenous fistulas

INTRODUCTION

One of the most important problems for patients undergoing hemodialysis due to chronic renal failure is the need for a long-lasting vascular access. The patency of vascular access is affected by many factors. Factors related to surgery are also among these factors. No-touch techniques theoretically and practically prevent endothelial damage due to minimal contact on vascular structures. It is a well-known fact that surgeries performed with these methods also increase long-term survival.

METHODS

Patients who underwent distal radiocephalic arteriovenous fistula (AVF) surgery for the first time between 2017 and 2021 were included in our study. The groups, whose cephalic veins were inflated conventionally and not inflated, were compared in a prospective randomized manner.

RESULTS

There was a significant difference between both groups in terms of failure and patency rates, which is one of the study endpoints (p = 0.012). The fact that the patency period is long, and the failure rate is low stands out as the superiority of the fully no-touch technique in AVF surgery. On the other hand, no significant difference was observed in terms of failure to maturation and fistula maturation time.

CONCLUSIONS

Fully no-touch technique in AVF surgery should be considered primarily in suitable patients due to its long patency time and low failure rate.

Effect of F11 Receptor/Junctional Adhesion Molecule-A-derived Peptide on Neointimal Hyperplasia in a Murine Model

PURPOSE

To determine whether inhibition of the F11 receptor/JAM-A (F11R) using F11R-specific antagonist peptide 4D results in inhibition of smooth muscle cell (SMC) proliferation and migration in vivo, known as neointimal hyperplasia (NIH), using a mouse focal carotid artery stenosis model (FCASM).

MATERIALS AND METHODS

The mouse FCASM was chosen to test the hypothesis because the dominant cell type at the site of stenosis is SMC, similar to that in vascular access stenosis. Fourteen C57BL/6 mice underwent left carotid artery (LCA) partial ligation to induce stenosis, followed by daily injection of peptide 4D in 7 mice and saline in the remaining 7 mice, and these mice were observed for 21 days and then euthanized. Bilateral carotid arteries were excised for histologic analysis of the intima and media areas.

RESULTS

The mean intimal area was significantly larger in control mice compared with peptide 4D-treated mice (0.031 mm2 [SD ± 0.024] vs 0.0082 mm2 [SD ± 0.0103]; P = .011). The mean intima-to-intima + media area ratio was significantly larger in control mice compared with peptide 4D-treated mice (0.27 [SD ± 0.13] vs 0.089 [SD ± 0.081]; P = .0079). NIH was not observed in the right carotid arteries in both groups.

CONCLUSIONS

Peptide 4D, an F11R antagonist, significantly inhibited NIH in C57BL/6 mice in a FCASM.

Effect of exercises on the maturation of newly created arteriovenous fistulas over distal and proximal upper limb: A systematic review and meta-analysis

The aims of our review were: (i) to evaluate the effect of post-operative upper extremity exercise on maturation of AVFs, stratified by their locations. (ii) To evaluate the effect of pre-operative arm exercise on patients' superficial vein caliber of patients. Literature search was performed on PubMed, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and China National Knowledge Infrastructure (CNKI) to identify eligible articles. The quality of the randomized controlled trials (RCTs) were assessed using the Cochrane Risk of Bias tool 2.0. In the Meta-analysis, Risk ratios (RRs) of clinical maturation and ultrasonographic maturation were pooled from studies focused on post-operative exercise program; Mean difference (MD) of venous caliver was pooled from those studied pre-operative exercise. Nine studies (six for post-operative exercise; three for pre-operative exercise) were included in the review. Among the AVFs created in distal region (158 patients in exercise group and 144 patients in control group), there was a significantly superior clinical maturation (RR: 1.28; 95% CI: 1.10-1.48, p = 0.001; I2 = 0), and ultrasonographic maturation (RR: 1.30; 95% CI: 1.07-1.59, p = 0.009; I2 = 0) in the exercise group in comparison to the control group. For the AVFs created in proximal region (93 and 96 patients in exercise group and control group respectively), there is no significant difference in clinical maturation (RR:1.25, 95% CI: 0.88-1.78, p = 0.27, I2 = 74%) and ultrasonographic maturation (RR: 1.17, 95% CI: 0.97-1.40, p = 0.11, I2 = 43%) between the exercise group and controls. For pre-operative exercise, the mean difference of 0.34 mm (95% CI: 0.23-0.46, p < 0.001, I2 = 87% ) was found for vein size. In conclusion, existing upper extremity exercise programs appear to be useful in facilitating maturation of AVFs created in distal region, while its effect on fistulas created in proximal region is less certain. However, more robust trials are warranted to establish these findings.

Outcome after early thrombotic occlusion of arteriovenous fistulas

OBJECTIVE

Arteriovenous fistulas (AVFs) are considered the first choice for venous access in end-stage renal disease patients, however, they are also known to have a high primary failure rate (early thrombosis and maturation failure). Of these, the outcome of thrombosed immature AVFs is not well known. This study aimed to investigate the outcome of AVFs with early thrombosis.

METHODS

Patients who underwent AVF creation from January 2009 to December 2019 at Seoul National University Hospital or Seoul Metropolitan Government - Seoul National University Boramae Medical Center were retrospectively reviewed. Patients who received salvage operations due to early thrombosis within 30 days after access creation were analyzed.

RESULTS

During the study period, a total of 45 patients (radiocephalic 26; brachiocephalic 19) developed early thrombosis and underwent salvage operations. The median age of patients was 61.0 (54.5-69.5) years, and 51.1% were male. The first salvage operation was performed on the median 1.0 (0.0-4.5) day after AVF creation. The most common cause for early thrombosis was venous stenosis (64.4%) and followed by poor arterial inflow (28.9%), especially in radiocephalic AVFs. About 20 AVFs were salvaged to maturation (46.5%). Post-salvage primary patency and secondary patency at 1 year was 72.6% and 100%. In a multivariate logistic regression, significant risk factors for maturation failures were minimum venous outflow diameter ⩽2.5 mm (OR, 4.433; 95% CI, 1.039-18.921; p = 0.044) and lower in patients with hypertension (OR, 0.064; 95% CI, 0.006-0.637; p = 0.019).

CONCLUSIONS

Thrombosed immature AVFs are associated with a high failure rate after salvage operation. However, if the salvage operation is successfully performed, it is associated with an acceptable 1-year outcome.

VasQ U.S. pivotal study demonstrates the safety and effectiveness of an external vascular support for arteriovenous fistula creation

OBJECTIVE

Arteriovenous fistula (AVF) creation is a commonly performed vascular operation that reports 6-month functional success rates as low as 50%. Recently, a nitinol external vascular support device, VasQ, has shown potential in studies outside the United States (U.S.) to improve AVF outcomes when implanted at creation. Here, the pivotal study results of this novel technology in treating patients in the U.S. are described.

METHODS

VasQ was implanted in 144 patients at 16 centers across the U.S. who were referred for creation of a new AVF and consented for enrollment in a 2-year, prospective, multicenter, single-arm, open-label study. Brachiocephalic (n = 129) and radiocephalic (n = 15) AVFs were analyzed. The primary endpoint was primary patency at 6 months compared against a performance goal of 55% derived from a systematic literature search. Safety endpoints included device-related events, ischemic steal, infection, aneurysm, and seroma at up to 6 months. Minimum arterial size was 2.0 mm; target veins were required to measure 2.5 to 6 mm. Key exclusion criteria were patients <18 or >80 years, those with known ipsilateral central venous occlusion, target cannulation zone venous depth greater than 8 mm, and New York Heart Association class 3 or 4.

RESULTS

Patients were 61% male, 53% White, 35% African American, and 14% Hispanic. Mean age was 60 years, and median body mass index was 30.4. Of the patients, 69% were diabetic, 66% were on dialysis at the time of creation, and 70% had a prior access surgery. At 6 months, steal was observed in 2.1%, infection in 0.7%, and no aneurysms or seromas were seen. Primary patency at 6 months was 66% (P < .021 vs performance goal). Physiological maturation was achieved in 92.4% of patients. Successful two-needle cannulation for patients that entered the study on dialysis was achieved in 88% of VasQ AVFs at a median of 56 days. Pre-dialysis patients who initiated dialysis during the study achieved two-needle cannulation in 81.6% VasQ AVFs. Interventions were required at a rate of 1.07 per patient year over the entire study period. Two-year cumulative patency was 76.6% (95% confidence interval, 67.9%-83.4%) with no statistical difference between patients requiring interventions and those that did not. No patency differences were observed between brachiocephalic and radiocephalic AVFs.

CONCLUSIONS

The U.S. pivotal study results demonstrated improved AVF outcomes and an excellent safety profile with VasQ use relative to traditional AVFs. Under the conditions of this trial, VasQ shows great promise in expeditiously and efficiently enhancing AVF functional success.

Elevated plasma leptin levels are associated with vascular access dysfunction in patients on maintenance hemodialysis

BACKGROUND

Inflammation has been associated with vascular access (VA) dysfunction. The adipocytokine leptin can directly induce pro-inflammatory T helper 1 immune responses and the pathogenesis of chronic inflammation. We explored the association between plasma leptin and VA dysfunction in patients on maintenance hemodialysis (HEMO).

METHODS

A total of 344 consecutive patients who received anastomosis for VA at a single HEMO center between June 1, 2010 and December 31, 2021 were screened. Of these patients, 267 met the inclusion criteria and were included. ELISA was used to measure circulating levels of leptin.

RESULTS

The VA dysfunction group had a higher leptin level than the patent VA group. A higher concentration of leptin was independently and significantly associated with an elevated risk of VA dysfunction. Multiple logistic regression analysis showed that leptin, female sex, and hypertension were independently associated with VA dysfunction, even after adjusting for known biomarkers. We then evaluated the ability of leptin, female sex, and hypertension to predict the risk of VA dysfunction, and the area under the curve (AUC) for leptin was 0.626 (p = 0.0001). When leptin, female sex, and hypertension were added to this multivariate model, the AUC increased to 0.679 (p = 0.001) for leptin and hypertension, and 0.690 for leptin, hypertension, and female sex (p = 0.004). In addition, plasma leptin levels were associated with sex, body mass index, and hemoglobin.

CONCLUSIONS

In addition to the association between leptin and VA dysfunction, hypertension and female sex independently predicted VA dysfunction in patients with HEMO.

Long-term patency of arteriovenous fistulas for hemodialysis: A decade's experience in a transplant unit

BACKGROUND

The heterogeneous quality of studies on arteriovenous fistulas outcome, with variable clinical settings and large variations in definitions of patency and failure rates, leads to frequent misinterpretations and overestimation of arteriovenous fistula patency. Hence, this study aimed to provide realistic and clinically relevant long-term arteriovenous fistula outcomes.

METHODS

We retrospectively analyzed all autologous arteriovenous fistulas at our center over a 10-year period (2012-2022). Primary and secondary patency analysis was conducted using the Kaplan-Meier method; multivariate analysis of variance was used to detect outcome predictors. Vascular access-specific endpoints were defined according to the European guidelines on vascular access formation.

FINDINGS

Of 312 arteriovenous fistulas, 57.5% (n = 181) were radio-cephalic (RC_AVF), 35.2% (n = 111) brachio-cephalic (BC_AVF), and 6.3% (n = 20) brachio-basilic (BB_AVF). 6, 12, and 24 months follow-up was available in 290 (92.1%), 282 (89.5%), and 259 (82.2%) patients, respectively. Primary patency rates at 6, 12, and 24 months were 39.5%, 34.8%, and 27.2% for RC_AVF, 58.3%, 44.4%, and 27.8% for BC_AVF, and 40.0%, 42.1%, and 22.2% for BB_AVF (p = 0.15). Secondary patency rates at 6, 12, and 24 months were 65.7%, 63.8%, and 59.0% for RC_AVF, 77.7%, 72.0%, and 59.6% for BC_AVF, and 65.0%, 68.4%, and 61.1% for BB_AVF (p = 0.29). Factors associated with lower primary and secondary patency were hemodialysis at time of arteriovenous fistula formation (p = 0.037 and p = 0.024, respectively) and higher Charlson Comorbidity Index (p = 0.036 and p < 0.001, respectively). Previous kidney transplant showed inferior primary patency (p = 0.005); higher age inferior secondary patency (p < 0.001).

DISCUSSION

Vascular access care remains challenging and salvage interventions are often needed to achieve maturation or maintain patency. Strict adherence to standardized outcome reporting in vascular access surgery paints a more realistic picture of arteriovenous fistula patency and enables reliable intercenter comparison.

Trans-radial percutaneous intervention for thrombosed hemodialysis access: A single-center experience

BACKGROUND

Traditionally, percutaneous transluminal angioplasty (PTA) is a first-line approach for stenosed dialysis accesses and has been performed through the non-thrombosed vein segment. For thrombosed accesses, thrombectomy (whether open or percutaneous) is a standard approach. The primary objective of our study is to determine the clinical and technical outcomes of the trans-radial approach of PTA among thrombosed dialysis accesses, in terms of safety and feasibility, technical and clinical aspects and factors influencing them, as well as assisted primary patency, secondary patency at 6 and 12 months.

METHODS

This is a single-center retrospective study that included 150 patients over 3 years. About 123 patients underwent successful percutaneous balloon angioplasty through the radial access.

RESULTS

We report an overall technical and clinical success rate of 82%, assisted primary patency rate of about 90.25% at 3 months, 82.93% at 6 months, 73.18% at 1 year, and secondary patency rate of 94% at 1 year. Twenty-seven patients were referred for surgical revisions/creation of a new fistula for reasons like inability to pass wire (6 patients), unfavorable anatomical variations like aneurysms at the proximal segments (5 patients), inability to cross the fistula (5 patients), and persistent fistula dysfunction with no flow after initial balloon dilatation (11 patients). Three patients had hematoma at the radial access site (2.5%) while two patients had the AV fistula segment rupture and were successfully treated conservatively.

CONCLUSION

We conclude that PTA through the trans-radial approach to completely thrombosed hemodialysis accesses is a good alternative to transvenous access and has a very good assisted primary patency and secondary patency at 1 year without major complications.

Comparing non-invasive diagnostic methods for arteriovenous fistula stenosis: a prospective study

PURPOSE

International guidelines recommend screening for arteriovenous fistula (AVF) stenosis using various non-invasive methods. We evaluate different non-invasive AVF flow measurements for detecting AVF stenosis.

METHODS

Twenty-three haemodialysis patients with suspected AVF stenosis are enrolled based on abnormal physical signs or high venous pressure during dialysis. Ultrasound dilution, urea dilution, Doppler ultrasonography, and fistulography are performed on all patients. The accuracy of three non-invasive methods is compared.

RESULTS

Fistulography reveals AVF stenosis in 18 patients, 12 of whom have severe stenosis (greater than 50% stenosis in diameter). Concerning the location of the stenosis lesions, eight are at the inflow site, six at the outflow site, and four on both sites. Receiver operating characteristic curve analysis shows that Doppler ultrasonography has a high discriminative ability and the averaged areas under the curves are 0.933 (95% confidence interval [CI]; 0.81 to 0.99) for stenosis and 0.929 (95% CI 0.82-0.99) for severe stenosis. The sensitivity of each method for the prediction of access stenosis using ultrasound dilution, urea dilution, and Doppler ultrasonography is 73%, 73%, and 80%, respectively. The respective specificity of each method is 40%, 80%, and 100%, respectively. Physical examination (PE) shows an 80% sensitivity and 80% specificity in the detection of AVF stenosis. The combination of Doppler ultrasound with PE produces the highest sensitivity (93%) for detecting AVF stenosis.

CONCLUSIONS

Doppler ultrasound combined with physical examination is more accurate than other non-invasive methods for detecting AVF stenosis.

The Impact of COVID-19 Infection Control Measures on End-Stage Renal Disease Patients in a Community Hemodialysis Setting

INTRODUCTION

Several non-pharmaceutical infection control measures have been implemented at community-based hemodialysis centers to reduce the risk of Coronavirus Disease of 2019 (COVID-19) transmission, caused by the SARS-CoV-2 virus. However, there have been concerns that such measures may disrupt the routine and timely care required by patients, with adverse effects on their health outcomes. This cross-sectional study aims to determine the unintended consequences of COVID-19 infection control measures on hemodialysis patients.

METHODS

 Electronic medical records were extracted from patients enrolled in community-based hemodialysis centers in Singapore. A baseline group prior of patients consisted of those enrolled in 2017, which was three years prior to the SARS-CoV-2-related pandemic (n = 548). This was compared with the study group of patients enrolled in 2019 (n = 426), just before the COVID-19 pandemic started. Medical records for these two groups were extracted from January to July 2018 for the baseline group and from January to July 2020, respectively. Three regression models were built to study dialysis adherence, kidney disease biomarkers, and hospitalization episodes.

RESULTS

 There was no statistically significant difference in hospitalization and mortality outcomes, adherence to dialysis management, laboratory results for dialysis-related clearance, and anemia outcomes. There was a higher proportion of patients hospitalized for vascular access-related reasons in the study group as compared to the baseline group (OR 1.6, 95% CI: 1.10 to 2.29, P = 0.014). Patients in the study group had albumin levels 2.13% higher (95% CI: 0.88 to 3.39, P < 0.001) and alkaline phosphatase levels 7.3% lower (95% CI: 1.17 to 13.02, P = 0.020) than those in the baseline group.

CONCLUSIONS

 From this community-based hemodialysis study in Singapore, it was shown that the COVID-19 pandemic did not disrupt regular healthcare services for these patients. With strategies instituted for a coordinated health delivery workflow, ensuring sufficient capacity in the various healthcare delivery sites and overall pandemic preparedness, the patient clinical outcomes measures continued to be met with no adverse consequences noted. Some improvements in dialysis-related laboratory values and quality of care targets may be due to more stringent measures instituted to protect these vulnerable patients in the community.

Sedoanalgesia with intravenous midazolam and fentanyl for angioplasty of dysfunctional arteriovenous access: A retrospective single-center analysis

BACKGROUND

Endovascular therapy, such as percutaneous transluminal angioplasty (PTA), stenting, or embolization, is a well-established form of treatment to prolong the lifespan of arteriovenous access. These procedures, especially PTA, can be accompanied with severe pain. We reviewed and analyzed the efficacy, safety, and outcome of sedoanalgesia using intravenous midazolam and fentanyl, for pain relief during these procedures.

METHODS

Two hundred and two consecutive patients with dysfunctional dialysis access that had undergone endovascular procedure in our institute between July and November 2017 were included in this study. The dialysis access profile, procedure complication, and 10-point Visual Analog Scale (VAS) were collected. One-year clinical follow-up record was also collected to evaluate arteriovenous access patency and long-term complications.

RESULTS

Among the 202 patients, the mean age was (mean ± SD) 67.0 ± 12.08 years. Dialysis access profile of these patients were 119 (58.9%) native arteriovenous fistula and 162 (74.2%) forearm access. The number of lesions treated were 1.63 ± 0.802.Immediate complications included 11 (5.44%) nausea/vomiting, 24 (11.88%) desaturation (SpO2 < 90%, resolved after pillow removal or jaw trust), 16 (7.9%) hypotension (SBP < 90 mmHg, resolved without inotropic agents). There was a low average pain score (1.16 ± 1.594) during the procedure with 136 (67.3%) no pain (VAS 0-1) and 56 (27.7%) mild pain (VAS 2-4). Higher VAS score correlated with overweight patients, longer PTA time and pain after procedure. Six-month primary patency rate was 49.17% and primary assisted patency rate was 93.04%.

CONCLUSIONS

Sedoanalgesia with intravenous midazolam and fentanyl is an easy, safe, and effective method for surgeons.

Mid-term cumulative patency of fistula and PTFE grafts among hemodialysis patients: A retrospective, single-center study from Palestine

BACKGROUND

Due to the long waiting time for kidney transplantation, most End-Stage renal disease patients are commenced on either hemodialysis or peritoneal dialysis. Reusable fistulas have the lowest risk for death, cardiovascular events, and infections among all vascular accesses. This study aims to report the outcomes of the arteriovenous fistulas and PTFE grafts and the related predictive clinical and demographic variables.

METHODS

This retrospective study reviewed the charts of all hemodialysis patients between January 2017 and January 2021 at the Dialysis Center of An-Najah National University Hospital, Nablus, Palestine. Our outcomes were a primary failure, primary and secondary patency, and the related factors. Survival analysis using the Kaplan-Meier method was conducted, and the log-rank test was used to compare patency rates. The Cox proportional hazards regression model tested factors relevant to primary and secondary patency rates in univariate and multivariate analyses.

RESULTS

A total of 312 procedures were performed during the study period. Primary failure was 7.1% for AVF, 13.9% for arterio-venous graft (AVG) procedures. Peripheral arterial disease and left-sided AVF were associated with more primary failure rates. AVF, primary patency rates at 1, 2, and 3 years were 82%, 69%, and 59%, respectively, while secondary patency rates at 1, 2, and 3 years were 85%, 72%, and 63%, respectively. Factors associated with increased AVF patency in a proportional hazard model were younger age and dual antiplatelet administration.

CONCLUSION

Our study adds further evidence that autogenous AVF has better results than prosthetic AVG in both primary and secondary patency rates as well as less primary failure rates. Therefore, we encourage further longitudinal studies that assess the benefits of using antiplatelet on AVF outcome versus risks of bleeding, especially with dual agents.

Intimal CD31-Positive Relative Surfaces Are Associated with Systemic Inflammatory Markers and Maturation of Arteriovenous Fistula in Dialysis Patients

BACKGROUND

Arteriovenous fistula dysfunction is a widely disputed subject in the scientific literature on end-stage kidney disease (ESKD). The main cause of mortality and morbidity in these patients is the non-maturation or dysfunction of the arteriovenous fistula. Despite the many complications, the native arteriovenous fistula remains the gold standard in the treatment of these patients requiring renal replacement. This study aims to discuss the predictive role of some systemic inflammatory biomarkers (NLR, PLR, SII, IL-6), intimal hyperplasia, and neoangiogenesis (characterized by intimal-media CD31-positive relative surface) in arteriovenous fistula maturation failure.

METHODS

The present study was designed as an observational, analytical, and prospective study which included patients diagnosed with ESKD with indications of radio-cephalic arteriovenous fistula (RCAVF). Demographic data, comorbidities, preoperative laboratory data and histological/digital morphometry analysis results were processed. The patients included were divided into two groups based on their AVF maturation status at 8 weeks: "Maturation" (Group 1) and "Failed Maturation" (Group 2).

RESULTS

There was no difference in the demographic data. In terms of comorbidities, the second group had a greater incidence of heart failure (p = 0.03), diabetes (p = 0.04), peripheral artery disease (p = 0.002), and obesity (p = 0.01). Additionally, regarding the laboratory findings, these patients had higher levels of serum uric acid (p = 0.0005), phosphates (p < 0.0001), and creatinine (p = 0.02), as well as lower levels of total calcium (p = 0.0002), monocytes (p = 0.008), and lymphocytes (p < 0.0001). Moreover, all inflammatory markers (p = 0.001; p < 0.0001; p = 0.006, and p = 0.03) and Ca-P product (p < 0.0001) had higher baseline values in Group 2. Upon immunohistochemical analysis, regarding the density of neoformed vessels, there was a higher incidence of CD31-positive surfaces (p = 0.006) and CD31-positive relative surfaces (p = 0.001); the NLR (r = 0.323; p = 0.03), PLR (r = 0.381; p = 0.04), SII (r = 0.376; p = 0.03), and IL-6 (r = 0.611; p < 0.001) are all significantly correlated with vascular density, as evidenced by CD31.

CONCLUSIONS

Heart failure, peripheral artery disease, obesity, and diabetes, as well as the systemic inflammatory markers (NLR, PLR, SII, IL-6), intimal hyperplasia, and CD31-positive relative surfaces are predictors of arteriovenous fistula maturation failures.

Comparison of clinical examination, doppler and fistulogram for arterio-venous fistula surveillance in detecting secondary failure

BACKGROUND

Arteriovenous Fistula (AVF) surveillance is required to detect early dysfunction (thrombosis, stenosis) and its timely correction prolongs access-patency. Clinical examination (CE) and doppler have been used as screening/surveillance of AVF, for early detection of AVF dysfunction. Since there was inadequate evidence for KDOQI to make recommendations on AVF surveillance and on secondary failure rate. We compared CE, doppler and fistulogram as surveillance modalities in detecting a secondary failure in matured AVF.

METHODOLOGY

This prospective-observational, single-center study, was done between December 2019-April 2021. CKD stage 5 patients on dialysis/Not-on-dialysis with matured AVF were included at third month. CE, doppler (blood flow, vein diameter, depth), and fistulogram were done at third and sixth month. Secondary failure was assessed at sixth month classifying AVF to patent/functional and failed group. Diagnostic tests were performed by comparing three methods considering fistulogram as gold-standard. Residual urine output is also monitored to look for any contrast induced residual renal function loss.

RESULTS

Of total 407 created AVF, 98 (24%) had primary failure. Twenty-five (6%) had surgical complications including unsuccessful AVF and aneurysm/rupture, 156 lost follow-up at third month, 104 consented patients were enrolled, 16 lost to follow-up subsequently, and 88 patients' data were analyzed at the end. At the sixth month, 76(86.4%) had patent AVF, 8 (9.1%) had secondary failure (Thrombosis-4, Central Venous Stenosis-4), and 4 (4.1%) patients expired. Considering fistulogram as a diagnostic standard, CE showed 87.5% sensitivity, and 93.4% specificity (cohen's kappa value of 0.66). Doppler had sensitivity and specificity of 87% and 96% respectively (cohen's kappa value of 0.75), Combination of clinical examination with doppler showed sensitivity and specificity of 100% and 89% respectively.

CONCLUSION

Although the secondary AVF failure rate is less than the primary, CE is an important and valuable tool in the diagnosis and surveillance of AVF in detecting its dysfunction. Moreover, CE with doppler can be used as a surveillance protocol that can detect early AVF dysfunction at par with Fistulogram.

Long-term efficacy and risk factors of balloon-assisted maturation for radial-cephalic arteriovenous fistula with small-caliber veins

INTRODUCTION

Balloon angioplasty maturation (BAM) is a salvage method for autologous arteriovenous fistula (AVF) maturation failure. AVF creation using small-diameter veins is considered to have poor outcomes. Therefore, this study aimed to explore the long-term patency of small-diameter veins (≤3 mm) using BAM.

METHODS

BAM was performed if the fistula failed to mature and function adequately to provide prescribed dialysis.

FINDINGS

Out of 61 AVFs, 22 AVFs successfully matured without further intervention (AVF group) and 39 AVFs failed to mature. Except for 1 patient who required peritoneal dialysis, the remaining 38 patients received salvage BAM, and 36 of those successful matured (BAM group). Kaplan-Meier analysis revealed no significant differences between the AVF and BAM groups in terms of primary functional patency (p = 0.503) and assisted functional patency (p = 0.499). Compared with the AVF group, the BAM group had similar assisted primary functional patency (1-year: 94.7% vs. 93.1%; 3-year: 88.0% vs. 93.1%; 5-year: 79.2% vs. 88.3%). In addition, there were no significant difference between groups in the duration of primary functional patency and assisted primary functional patency (p > 0.05). Multivariate analyses showed that vein diameter and number of BAM procedures were independent predictors of primary functional patency in the AVF group and BAM group, respectively. Patient with 1 mm increase in vein size had 0.13-fold probability of having decreased duration of patency (HR = 0.13, 95% CI: 0.02-0.99, p = 0.049), while patients who received two times of BAM procedures were 2.885 as likely to have decreased duration of primary functional patency (HR = 2.885, 95% CI: 1.09-7.63, p = 0.033) than patients who received one BAM procedure.

DISCUSSION

BAM is a relatively effective salvage management option with an acceptable long-term patency rate, even for small cephalic veins.

Reassessing the utility of access recirculation and Kt/V for the prediction of arteriovenous fistula failure using online clearance monitoring: the SHUNT STUDY

BACKGROUND

The arteriovenous fistula (AVF) is prone to thrombosis which can be avoided by use of monitoring and surveillance programmes. Although surveillance imaging techniques have been shown to be more sensitive and specific than clinical monitoring during dialysis, monitoring may have significant advantages in terms of cost and time saving. In this study we evaluate the yield of two monitoring techniques [blood temperature monitoring (BTM) access recirculation (AR) and Kt/V via online-clearance-monitoring (OCM)].

METHODS

In this single-centre prospective observational study, 101 patients were followed-up for one year. The primary outcome measure was a composite of AVF failure. OCM-Kt/V and BTM-AR were recorded at every dialysis session.

RESULTS

Of all baseline characteristics only a prior history of percutaneous transluminal angioplasty (PTA) to the AVF conferred a significant change in AVF survival (failure events/100 pt years with prior PTA vs. without = 64.0 vs. 17.3, log-rank p = 0.0014; unadjusted hazard ratio (HR) 3.74 (95% CI 1.56-8.94) p = 0.003). Participants with baseline AR < 10% vs. > 15% had poorer AVF survival (p = 0.0002) and HR for baseline AR 10-15% group vs. AR > 15% group = 4.5 (95% CI 1.55-13.05). There was no combination of change in (Δ) AR, ΔKt/V or its presence over any number of dialysis sessions that provided an acceptable combination of sensitivity and specificity or discrimination for AVF failure.

CONCLUSIONS

BTM-AR and OCM-Kt/V are specific but insufficiently sensitive tools for the prediction of AVF failure. BTM-AR and OCM-Kt/V use at every dialysis session appears to add little to the traditional, infrequent use of these evaluations.

The Transcriptomics of the Human Vein Transformation After Arteriovenous Fistula Anastomosis Uncovers Layer-Specific Remodeling and Hallmarks of Maturation Failure

Introduction

The molecular transformation of the human preaccess vein after arteriovenous fistula (AVF) creation is poorly understood. This limits our ability to design efficacious therapies to improve maturation outcomes.

Methods

Bulk RNA sequencing (RNA-seq) followed by paired bioinformatic analyses and validation assays were performed in 76 longitudinal vascular biopsies (veins and AVFs) from 38 patients with stage 5 chronic kidney disease or end-stage kidney disease undergoing surgeries for 2-stage AVF creation (19 matured, 19 failed).

Results

A total of 3637 transcripts were differentially expressed between veins and AVFs independent of maturation outcomes, with 80% upregulated in fistulas. The postoperative transcriptome demonstrated transcriptional activation of basement membrane and interstitial extracellular matrix (ECM) components, including preexisting and novel collagens, proteoglycans, hemostasis factors, and angiogenesis regulators. A postoperative intramural cytokine storm involved >80 chemokines, interleukins, and growth factors. Postoperative changes in ECM expression were differentially distributed in the AVF wall, with proteoglycans and fibrillar collagens predominantly found in the intima and media, respectively. Interestingly, upregulated matrisome genes were enough to make a crude separation of AVFs that failed from those with successful maturation. We identified 102 differentially expressed genes (DEGs) in association with AVF maturation failure, including upregulation of network collagen VIII in medial smooth muscle cells (SMCs) and downregulation of endothelial-predominant transcripts and ECM regulators.

Conclusion

This work delineates the molecular changes that characterize venous remodeling after AVF creation and those relevant to maturation failure. We provide an essential framework to streamline translational models and our search for antistenotic therapies.

Achieving high maturation and cannulation rates of radial-cephalic arteriovenous fistulas with VasQ™ device

BACKGROUND

Hemodialysis is the predominant treatment modality for chronic kidney disease, with arteriovenous fistula (AVF) being considered to be the preferred type of long-term vascular access. Implantation of the external anastomotic VasQ™ support device during AVF creation has been suggested to improve the functional outcomes of AVFs. In the current study, we report the clinical outcomes when using the device with radial-cephalic AVF (RCAVF) creation in a large cohort over 3 years.

METHODS

One hundred fifty RCAVFs were created between June 2018 and August 2021 with implantation of VasQ™. Time to maturation, cannulation characteristics, and assisted (AP) and secondary patency (SP) rates were analyzed.

RESULTS

In this predominantly male (68%), median 64 years old cohort, 150 VasQ™ devices were implanted. Physiological maturation was achieved in 142/150 (95%) and was unassisted in 133/150 (89%). Of those, 129 matured within 1 month and four additional AVFs within 165 days. Eight AVFs achieved maturation following percutaneous transluminal angioplasty, and one required surgical patch angioplasty. The median time from creation to first successful cannulation in dialysis patients was 41 days. AP at 6, 12, 18, 24, and 30 months was 89%, 81%, 78%, 73%, and 73%, and SP was 94%, 87%, 86%, 84%, and 84%, respectively.

CONCLUSIONS

Consistent use of the VasQ™ device in RCAVF creation demonstrates excellent AVF maturation and patency rates with very low frequency of assisted maturation and interventions for maintenance. The VasQ™ device appears a suitable aid in increasing the creation of functional RCAVFs.

Plasma Interleukin-6 Level Predicts the Risk of Arteriovenous Fistula Dysfunction in Patients Undergoing Maintenance Hemodialysis

Systemic inflammation has been proposed as a relevant factor of vascular remodeling and dysfunction. We aimed to identify circulating inflammatory biomarkers that could predict future arteriovenous fistula (AVF) dysfunction in patients undergoing hemodialysis. A total of 282 hemodialysis patients were enrolled in this prospective multicenter cohort study. Plasma cytokine levels were measured at the time of data collection. The primary outcome was the occurrence of AVF stenosis and/or thrombosis requiring percutaneous transluminal angioplasty or surgery within the first year of enrollment. AVF dysfunction occurred in 38 (13.5%) patients during the study period. Plasma interleukin-6 (IL-6) levels were significantly higher in patients with AVF dysfunction than those without. Diabetes mellitus, low systolic blood pressure, and statin use were also associated with AVF dysfunction. The cumulative event rate of AVF dysfunction was the highest in IL-6 tertile 3 (p = 0.05), and patients in tertile 3 were independently associated with an increased risk of AVF dysfunction after multivariable adjustments (adjusted hazard ratio = 3.06, p = 0.015). In conclusion, circulating IL-6 levels are positively associated with the occurrence of incident AVF dysfunction in hemodialysis patients. Our data suggest that IL-6 may help clinicians identify those at high risk of impending AVF failure.

Gracz fistula is a feasible option after two failed percutaneous arteriovenous fistulae

Two devices for the creation of an endovascular percutaneous (pAVF) endovascular (endoAVF) arteriovenous fistulae (AVF) are available: the Ellipsys and the WavelinQ-4F systems. The main difference is the location of the anastomosis, making it feasible to use both pAVFs and surgical Gracz-type AVF in an algorithm sequence. A 66-year-old male patient with end-stage kidney disease and HIV was referred for a creation of a dialysis access after failed peritoneal dialysis. A radial-radial WavelinQ-pAVF with simultaneous coil embolization of a brachial vein was created but failed within 4 weeks. Therefore, an Ellipsys-pAVF was successfully created between the proximal radial artery and perforating vein on the same arm. After 2 days, however, the Ellipsys-pAVF anastomosis occluded. The ipsilateral Gracz-AVF was created, anastomosing perforating vein with the antecubital brachial artery. Cannulations were started 28 days later. During the follow up of 807 days, the AVF remained patent with last known volume flow of 1500 ml/min and no need for secondary interventions. We report a successful creation of a Gracz-AVF after primary failed pAVFs created with both pAVF-systems in a single patient and in the same arm. Thus, based on that case we recommend creation of pAVF prior to Gracz-AVF as integral part of Vascular Access creation algorithm, based on each patient's life plan.

Novel external stenting for reconstruction of high flow arteriovenous fistula

BACKGROUND

High-flow arteriovenous fistulae (HF-AVF) may lead to adverse cardiac remodeling in hemodialysis patients. We have investigated whether a novel external stent is safe and effective in reducing and stabilizing flow rates during a 1-year follow-up after HF-AVF reconstruction.

METHODS

All patients with HF-AVF (access flow rate ⩾ 1500 ml/min), who underwent HF-AVF reconstruction with external stenting in two centers between June 2018 and May 2020, were included in this retrospective analysis. During HF-AVF reconstruction, the dilated vein segment was resected, underwent volume reduction, and was externally stabilized using a braided cobalt-chromium external stent. AVF flow rates were assessed preoperatively, intraoperatively, and at follow up visits using duplex ultrasound.

RESULTS

Forty-three HF-AVFs in 42 patients were reconstructed and supported with an external stent (mean age 49 years, range 20-86 years; 74% men). Fifty-one percent were forearm AVFs, 49% were upper arm. The mean preoperative flow rate was 2622 ± 893 ml/min (range: 1500-6000 ml/min) and was decreased to 710 ± 221 ml/min (range: 300-1300 ml/min) intra-operatively after HF-AVF reconstruction. At 6 and 12-months follow-up, the mean flow rates were 1132 ± 320 ml/min (range: 470-1700 ml/min) and 1453 ± 888 ml/min (range: 300-3800 ml/min), respectively. Recurrence of high flow (>1500 ml/min) occurred in 16% and 25% of the patients at 6 and 12 months and primary patency rates were 86% and 70%, respectively.

CONCLUSIONS

This early experience with novel external stenting for HF-AVF reconstruction demonstrates that it is a safe and effective method for reducing and stabilizing flow rates up to 1-year post procedure. Additional studies are required to evaluate the durability of this procedure over the longer term and assess its effect on cardiac remodeling.

Primary Balloon Angioplasty Versus Hydrostatic Dilation for Arteriovenous Fistula Creation in Patients with Small-Caliber Cephalic Veins: A Systematic Review and Meta-Analysis

BACKGROUND

For arteriovenous fistula (AVF) presence of a venous segment with adequate diameter is essential which is lacking in many patients. To find the optimal augmentation technique in patients with small-caliber cephalic vein (i.e., cephalic vein diameter <3 mm), studies compared primary balloon angioplasty (PBA) versus hydrostatic dilation (HD); however, it remained debatable. This systematic review seeks to determine which technique is preferable.

METHODS

We searched MEDLINE, PubMed, Embase, and Google Scholar. Primary outcomes were 6-month primary patency, reintervention, and working AVF. Secondary outcomes were immediate success, the AVF's maturation time (day), and surgical site infection.

RESULTS

Three randomized controlled trials yielding 180 patients were included, of which 89 patients were in the PBA group. The odds ratio (OR) of primary patency was significantly higher in the PBA group (OR 6.09, 95% confidence interval [CI], 2.36-15.76, P = 0.0002), the OR of reintervention was significantly lower in the PBA group (OR 0.16, 95% CI, 0.06-0.42, P = 0.0002), and the OR of working AVF was greater in PBA group (OR 4.22, 95% CI, 1.31-13.59, P = 0.02). The OR of immediate success was significantly greater in the PBA group (OR 11.42, 95% CI, 2.54-51.42, P = 0.002), and the AVF maturation time was significantly shorter in patients who underwent PBA (mean difference -20.32 days, 95% CI, -30.12 to -10.52, P = 0.0001). The certainty of the evidence was high.

CONCLUSIONS

PBA of small cephalic veins with diameter ≤2.5 cm is a safe, feasible, and efficacious augmentation method for AVF creation. This technique achieves favorable maturation outcomes, and PBA is superior to the standard hydrostatic dilatation technique.

Oxidative stress: An essential factor in the process of arteriovenous fistula failure

For more than half a century, arteriovenous fistula (AVFs) has been recognized as a lifeline for patients requiring hemodialysis (HD). With its higher long-term patency rate and lower probability of complications, AVF is strongly recommended by guidelines in different areas as the first choice for vascular access for HD patients, and its proportion of application is gradually increasing. Despite technological improvements and advances in the standards of postoperative care, many deficiencies are still encountered in the use of AVF related to its high incidence of failure due to unsuccessful maturation to adequately support HD and the development of neointimal hyperplasia (NIH), which narrows the AVF lumen. AVF failure is linked to the activation and migration of vascular cells and the remodeling of the extracellular matrix, where complex interactions between cytokines, adhesion molecules, and inflammatory mediators lead to poor adaptive remodeling. Oxidative stress also plays a vital role in AVF failure, and a growing amount of data suggest a link between AVF failure and oxidative stress. In this review, we summarize the present understanding of the pathophysiology of AVF failure. Furthermore, we focus on the relation between oxidative stress and AVF dysfunction. Finally, we discuss potential therapies for addressing AVF failure based on targeting oxidative stress.

Endothelial Cell TGF-β (Transforming Growth Factor-Beta) Signaling Regulates Venous Adaptive Remodeling to Improve Arteriovenous Fistula Patency

BACKGROUND

Arteriovenous fistulae (AVF) are the gold standard for vascular access for hemodialysis. Although the vein must thicken and dilate for successful hemodialysis, excessive wall thickness leads to stenosis causing AVF failure. Since TGF-β (transforming growth factor-beta) regulates ECM (extracellular matrix) deposition and smooth muscle cell (SMC) proliferation-critical components of wall thickness-we hypothesized that disruption of TGF-β signaling prevents excessive wall thickening during venous remodeling.

METHODS

A mouse aortocaval fistula model was used. SB431542-an inhibitor of TGF-β receptor I-was encapsulated in nanoparticles and applied to the AVF adventitia in C57BL/6J mice. Alternatively, AVFs were created in mice with conditional disruption of TGF-β receptors in either SMCs or endothelial cells. Doppler ultrasound was performed serially to confirm patency and to measure vessel diameters. AVFs were harvested at predetermined time points for histological and immunofluorescence analyses.

RESULTS

Inhibition of TGF-β signaling with SB431542-containing nanoparticles significantly reduced p-Smad2-positive cells in the AVF wall during the early maturation phase (days 7-21) and was associated with decreased AVF wall thickness that showed both decreased collagen density and decreased SMC proliferation. SMC-specific TGF-β signaling disruption decreased collagen density but not SMC proliferation or wall thickness. Endothelial cell-specific TGF-β signaling disruption decreased both collagen density and SMC proliferation in the AVF wall and was associated with reduced wall thickness, increased outward remodeling, and improved AVF patency.

CONCLUSIONS

Endothelial cell-targeted TGF-β inhibition may be a translational strategy to improve AVF patency.

Percutaneous Hemodialysis Fistula Creation

Two devices have been recently introduced to European Union and North American clinical practice that allow for percutaneous creation of autogenous hemodialysis fistulas (pAVF). Although there are similarities between the devices, there are many differences. Adoption of either or both technologies by an interventionalist may be determined by the individual's comfort with the device. Importantly, current and future outcomes will shape acceptance and use of these devices. This review focuses on the similarities and differences of each device, the procedures, published outcomes to date and their interpretation and other clinical considerations towards initiation of a successful pAVF program.

Long Term Results from The Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access

PURPOSE

To report the five-year results from the Pivotal Multicenter Trial of Ultrasound Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access.

MATERIALS AND METHODS

Retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients followed a median 50 months (range 12-60). Data evaluated in the LTP group were fistula maturation and use, secondary procedures, and complications. Kaplan-Meier analysis of primary, primary assisted, cumulative patency, and functional patency (time from two-needle to abandonment) were performed for the ITT population.

RESULTS

In the LTP 99% (84/85) of fistulas were mature with 99% (78/79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (two-needle cannulation at prescribed rate, 2/3 sessions) was achieved in 92% (78/85) of patients, with seven patients never using their pAVF because not on dialysis (n=4), peritoneal dialysis (n=2), and refusing to use fistula (n=1). Fistula maintenance was required in 31.8% (27/85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year (PPPY) to maintain function and patency was 0.32 (91/288) for years 2-5. The cumulative patency was 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% years 1-5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during long-term follow-up CONCLUSION: Percutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. Continued use and evaluation of pAVF is warranted.

Contemporary Strategies to Promote Dialysis Access Fistula Maturation

Background: The inability of a newly created arteriovenous fistula to support hemodialysis due to non-maturation results in increased complications secondary to catheter dependence. Methods: In view of the highly variable approaches by providers with heterogenous backgrounds (general surgery, vascular surgery, interventional radiology and interventional nephrology, urology, transplant surgery, etc.) we sought to describe a collection of algorithms that have functioned well in our hands to manage this challenging clinical problem and guide trainees and practicing clinicians alike.Results: Physical examination along with selective duplex ultrasound and fistulogram can identify most pathologies underlying non-maturation.Conclusion: Both endovascular and open techniques can be employed to optimize maturation rates in this complex population.

The related factors to the re-thrombosis of hemodialysis arteriovenous graft after endovascular salvage

BACKGROUND

Only a few issues of the related factors to hemodialysis access dysfunction have been evaluated, and the effects of antiplatelets to improve the patency of hemodialysis access remained controversial. Hence, this study aimed to determine the related factors to the re-thrombosis of arteriovenous grafts (AVGs) after endovascular treatment.

METHODS

This retrospective study was conducted at a university-affiliated teaching hospital in Southern Thailand. All patients who underwent hemodialysis with thrombosed AVG, who had pharmacomechanical thrombolysis from January 2016 to December 2018, were enrolled. Post-intervention primary patency was analyzed by the Kaplan-Meier method, and the related factors to the re-thrombosis of AVG were evaluated using logistic regression.

RESULTS

A total of 157 patients with thrombosed hemodialysis AVG were enrolled. The most common graft location and configuration was a forearm loop graft (65%). Post-intervention primary patency rate at 1, 3, and 6 months were 79.0%, 67.1%, and 54.0%, respectively. Diabetes mellitus (DM) was a significant related factor for re-thrombosis (hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.20-2.98; p = 0.006). A single antiplatelet after the procedure was a protective factor for re-thrombosis (HR, 0.58; 95% CI, 0.38-0.89; p = 0.013). The median post-intervention primary patency was 15.7 months in the group of single antiplatelet usage, which was better than that of the non-antiplatelet group (p = 0.012).

CONCLUSION

DM and antiplatelet usage were significant related factors to the re-thrombosis of hemodialysis AVG after endovascular salvage.

Association of Permanent Vascular Access Dysfunction with Subsequent Risk of Cardiovascular Disease: A Population-Based Cohort Study

A functional permanent vascular access (VA) is required to perform a successful hemodialysis procedure. Hemodialysis VA dysfunction is a major cause of morbidity and hospitalization in the hemodialysis population. Cardiovascular disease (CVD) is the leading cause of death in patients receiving chronic hemodialysis. Information about CVD associated with hemodialysis VA dysfunction is unclear. We analyzed the association between dialysis VA dysfunction and the risk of developing CVD in hemodialysis patients. This nationwide population-based cohort study was conducted using data from the National Health Insurance Research Database in Taiwan. One million subjects were sampled from 23 million beneficiaries and data was collected from 2000 to 2013. Patients with end-stage renal disease who had received permanent VA construction and hemodialysis and were aged at least 20 years old from 2000 to 2007 were included in the study population. The primary outcome was CVD, as defined by ICD-9-CM codes 410–414 and 430–437. A total of 197 individuals with permanent VA dysfunction were selected as the test group, and 100 individuals with non-permanent VA dysfunction were selected as the control group. Compared with the control group, the adjusted hazard ratio of CVD for the VA dysfunction group was 3.05 (95% CI: 1.14–8.20). A Kaplan–Meier analysis revealed that the cumulative incidence of CVD was higher in the permanent VA dysfunction group than in the comparison group. Permanent VA dysfunction is significantly associated with an increased risk of subsequent CVD.

Weight-Based Assessment of Access Flow Threshold to Predict Arteriovenous Fistula Functional Patency

Introduction

The 2019 Kidney Disease Outcome Quality Initiative (K/DOQI) guideline recommended evaluating arteriovenous fistula (AVF) malfunction risks primarily based on clinical monitoring, which can be assisted with the value of vascular access flow (Qa). Nevertheless, Qa thresholds recommended by different guidelines vary, ranging from 300 to 500 ml/min. This study investigated the optimal Qa threshold to predict future functional patency in AVFs with Qa <500 ml/min.

Methods

Both the clinical indicators of access dysfunction and the Qa value were monitored in patients receiving hemodialysis by the radiocephalic AVF. Routine access flow surveillance was performed by the ultrasound dilution method (HD03, Transonic Inc.). The development of clinically significant indicators of access dysfunction, which necessitated percutaneous transluminal angiography (PTA) to maintain functional patency, was analyzed in this cohort.

Results

Among the enrolled 302 patients, Qa of 52 patients was under 500 ml/min. These 52 patients received 2 Qa measurements during the follow-up period. Of these 52 patients, serial Qa of 17 patients varied trivially and their AVF remained functional. Multivariable logistic regression analysis revealed that a low Qa per ideal body weight (IBW) is an independent predictor of AVF functional loss. Receiver operating characteristic curve analysis of Qa/IBW in predicting future AVF functional loss revealed that the best cutoff value of Qa is 7.1 times the IBW.

Conclusion

For radiocephalic AVFs with Qa <500 ml/min, the minimally required Qa to maintain access function is associated with individual IBW. The IBW-based Qa threshold assessment would allow more flexibility in the treatment of patients and reduce unnecessary invasive measures.

Inhibition of β-catenin signaling attenuates arteriovenous fistula thickening in mice by suppressing myofibroblasts

Background

Arteriovenous fistula (AVF) is the most important vascular access for hemodialysis; however, preventive treatment to maintain the patency of AVFs has not been developed. In endothelium, β-catenin functions in both the intercellular adherens complex and signaling pathways that induce the transition of endothelial cells to myofibroblasts in response to mechanical stimuli. We hypothesize that mechanical disturbances in the AVF activate β-catenin signaling leading to the transition of endothelial cells to myofibroblasts, which cause AVF thickening. The present study aimed to test this hypothesis.

Methods

Chronic kidney disease in mice was induced by a 0.2% adenine diet. AVFs were created by aortocaval puncture. Human umbilical vein endothelial cells (HUVECs) were used in the cell experiments. A pressure-culture system was used to simulate mechanical disturbances of the AVF.

Results

Co-expression of CD31 and smooth muscle alpha-actin (αSMA), loss of cell–cell adhesions, and the expression of the myofibroblast marker, integrin subunit β6 (ITGB6), indicated transition to myofibroblasts in mouse AVF. Nuclear translocation of β-catenin, decreased axin2, and increased c-myc expression were also observed in the AVF, indicating activated β-catenin signaling. To confirm that β-catenin signaling contributes to AVF lesions, β-catenin signaling was inhibited with pyrvinium pamoate; β-catenin inhibition significantly attenuated AVF thickening and decreased myofibroblasts. In HUVECs, barometric pressure-induced nuclear localization of β-catenin and increased expression of the myofibroblast markers, αSMA and ITGB6. These changes were attenuated via pretreatment with β-catenin inhibition.

Conclusions

The results of this study indicate that mechanical disturbance in AVF activates β-catenin signaling to induce the transition of endothelial cells to myofibroblasts. This signaling cascade can be targeted to maintain AVF patency.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00436-1.

Role of Endovascular Treatment in Dysfunctional Hemodialysis Fistulae: A Single Center Experience

Introduction

Arteriovenous fistulas (AVFs) are the preferred route of hemodialysis in end-stage renal disease. However, recurrent patency loss is an obstacle in long-term maintenance. Endovascular treatments may provide a durable option for prolongation of patency in AVFs.

Methods

Retrospective observational study was done on 46 patients with AVF for hemodialysis in the Department of Diagnostic and Interventional Radiology for a period of 1 year from September 2020 to August 2021. The characters of dysfunctional fistulas and results of various interventional procedures were assessed for technical and clinical success rates. Short-term follow-up records of patients were assessed for post-intervention primary patency (PIPP) and post-intervention assisted primary patency (PIAPP) of various procedures.

Results

The most successful outcomes post intervention were seen in radio-cephalic fistulas formed more than 1 year ago with juxta-anastomotic narrowing. The overall technical success rate was 89.13% with a PIPP of 78.26% and a PIAPP of 82.60% at 3 months. PTA had better technical success rates (88.23%) as compared to dysfunctional segments with thrombosis that underwent angioplasty and thromboaspiration (84.2%). Central venous stenosis undergoing PTA and stenting had a 100% success rate. At 3 months follow-up, PIPP was better among the angioplasty plus thromboaspiration group (73.7%), while PIAPP rate was better in the angioplasty subgroup at 82.35%.

Conclusion

Endovascular intervention is the first-line treatment in dysfunctional AVFs attributable to the multitude of options available, all of which have comparable outcomes, high success rates, and notable short-term patency.

Effect of Radiocephalic Anastomotic Length on the Maturation of Arteriovenous Fistula

BACKGROUND

A radiocephalic arteriovenous fistula (RCAVF) is associated with better long-term patency and fewer complications. However, RCAVF have lower maturation rate for hemodialysis compared with upper AVF or arteriovenous graft. We performed this study to determine the effect of the radiocephalic (RC) anastomotic length on the AVF maturation.

METHODS

We reviewed the patients who underwent RCAVF creation with a side-to-end manner from March 2015 to December 2018. AVF maturation was defined as successful hemodialysis (HD) in at least two consecutive sessions. We compared the possible factors including the RC anastomotic length between the initial HD success group and initial HD failure group.

RESULTS

A total of 114 patients underwent RCAVF creation: 72 males and 42 females (63.2% and 36.8%, respectively). The mean preoperative arteriotomy length of the AVF was 14.1 mm (range 11.0-16.0 mm). Out of 114 patients, initial HD was executed successfully in 83 patients (72.8%). Among the 31 patients with initial HD failure (27.2%) balloon angioplasty was successfully performed in 17 patients, failed in 4 patients, and not performed in 10 patients. The secondary success rate after balloon angioplasty was 87.7%. After factor analysis, pre-emptive AVF (P = 0.01), vein diameter (P < 0.001), and flow rate (P < 0.001) were revealed significant factors for initial HD success, but not RC anastomotic length of AVF (P = 0.55).

CONCLUSION

The length of the radiocephalic anastomosis does not affect the RCAVF maturation rate statistically. However, lengthening of arteriotomy on the radial artery may increase the initial success rate of HD.

Predictors of Mortality within 24 Months of Initial Arteriovenous Access Creation

INTRODUCTION

End Stage Renal Disease is increasingly common, with approximately 785,880 patients currently dialysis dependent in the United States. 86% of these patients utilize hemodialysis. Arteriovenous (AV) access with either a fistula or graft is preferred over a catheter due to lowered complication risk. The purpose of this paper is to identify mid- term predictors of mortality to guide the type of AV access in patients with suboptimal cephalic veins.

METHODS

This is a retrospective review of patient characteristics at the time of initial AV access placement. All patients receiving first time AV access were reviewed. Mortality data was found via electronic medical records review, social security death index review, and internet search. Patients in whom mortality data could not be found were excluded from the final analysis. Univariate analysis using Chi-Squared testing and Student T-Test was performed. Binary logistic regression analysis was also performed for multivariate investigation.

RESULTS

A total of 176 patients underwent first time AV access during the study period. Two year mortality data was available for 149 of these patients. Mortality occurred within 2 years for 27% of patients. Advanced age (70 vs. 61, P < 0.01), arrhythmia (48% vs. 24%, P < 0.01), abnormal EKG (36% vs.14%, P < 0.01), CHF (47% vs. 24%, P < 0.01), white, non-Hispanic race (51% vs. 22%, P < 0.01) and history of smoking (48% vs. 15%, P < 0.01) were statistically significant univariate predictors of 2-year mortality. Advanced age, white race and smoking were multivariate predictors with smoking having the largest impact (multivariate adjusted OR 11.8, P < 0.001).

CONCLUSIONS

History of tobacco smoking has a profoundly negative effect on two year survival in patients undergoing initial AV access. Absence of smoking history provides significant 2-year mortality protection and thorough attempt at autologous AVF creation should be made in these patients. Cardiac disease and advanced age continue to be lead predictors of mortality in ESRD patients.

Effect of cilostazol on arteriovenous fistula in hemodialysis patients

BACKGROUND

The maturation and patency of permanent vascular access are critical in patients requiring hemodialysis. Although numerus trials have been attempted to achieve permanently patent vascular access, little have been noticeable. Cilostazol, a phosphodiesterase-3 inhibitor, has been shown to be effective in peripheral arterial disease including vascular injury-induced intimal hyperplasia. We therefore aimed to determine the effect of cilostazol on the patency and maturation of permanent vascular access.

METHODS

This single-center, retrospective study included 194 patients who underwent arteriovenous fistula surgery to compare vascular complications between the cilostazol (n=107) and control (n=87) groups.

RESULTS

The rate of vascular complications was lower in the cilostazol group than in the control group (36.4% vs. 51.7%; p=0.033), including maturation failure (2.8% vs. 11.5%; p=0.016). The rate of reoperation due to vascular injury after hemodialysis initiation following fistula maturation was also significantly lower in the cilostazol group than in the control group (7.5% vs. 28.7%; p<0.001). However, there were no significant differences in the requirement for percutaneous transluminal angioplasty (PTA), rate of PTA, and the interval from arteriovenous fistula surgery to PTA between the cilostazol and control groups.

CONCLUSION

Cilostazol might be beneficial for the maturation of permanent vascular access in patients requiring hemodialysis.

Nuances of Arteriovenous Fistula Creation for Vascular Access in Hemodialysis

Background With rising incidence and increased life expectancy of patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD), the number of patients requiring hemodialysis has increased substantially. Vascular access is the lifeline for a patient on hemodialysis (HD), and an arteriovenous fistula (AVF) is the undisputed gold standard for HD access. An effective and long-lasting fistula serves to increase the life expectancy of ESRD patients and improves their quality of life.

Learning Objectives This paper aims to give a comprehensive overview of AVF creation, including the various techniques, patient selection, troubleshooting with decision-making, and common complications. Authors share their experience from previous publications and over 2000 AVF surgeries. They have not only described a new modification of the technique of proximal fistula but have also established a direct correlation between bruit and thrill on operation table and success of fistula surgery.

Conclusion A standardized, protocol-driven multidisciplinary approach with careful patient and site selection, guided by outcome predictors, is vital in AVF surgery. Knowledge about the potential complications of AVFs contributes to their timely detection and allows measures to be taken that might prevent deleterious consequences that range from loss of vascular access to serious morbidity and mortality.

Anticoagulation Therapy is Associated with Increased Access-related Wound Infections after Hemodialysis Access Creation

BACKGROUND

The effect of anticoagulation therapy (AC) on hemodialysis access patency and related complications is not well defined. Patients on long-term or chronic AC due to their underlying comorbid conditions may be particularly susceptible to access-related bleeding and complications from repetitive cannulation. Our goal is to assess the effect of anticoagulation therapy on outcomes after access creation.

METHODS

The Vascular Quality Initiative (VQI) database was queried for patients undergoing arteriovenous fistula (AVF) or graft (AVG) placement, from 2011 to 2019. Only patients with data on post-procedural AC status were included. Anticoagulation use was defined as patients on warfarin, dabigatran, or rivaroxaban after access creation at postoperative follow up. Demographic and procedural details were analyzed. Wound infection and patency rates at six months were assessed. Binomial logistic regression analysis was performed to assess the association of anticoagulation use with these outcomes.

RESULTS

A total of 27,757 patients underwent access creation, with the majority undergoing AVF creation (78.8%). The average age was 61.4 years and 55.3% were male. 12.9% of patients were on postoperative AC. The wound infection rate was 2.3- 3.8% in the no AC and AC cohorts, respectively (P < 0.001). At six months follow-up, patency was 85.7- 84.3% in the no AC and AC cohorts, respectively (P = 0.044). Expectedly, grafts had lower patency rates compared to AVF; those within the no AC cohort had a patency of 83.0% compared to 81.2 % in those on AC (P = 0.106). On multivariable analysis, anticoagulation use was associated with a higher risk of wound infections (odds ratio [OR] 1.513, 95% confidence interval [CI] 1.160-1.973, P = 0.002). AC use did not significantly affect access patency.

CONCLUSION

Anticoagulation therapy was associated with a higher rate of wound infections but did not affect short-term access patency within six-months. These patients warrant close surveillance of their access for signs of infection. Furthermore, long-term implications of anticoagulation needs further evaluation.

Percutaneous Arteriovenous Fistula Creation with the 4 French WavelinQ™ EndoAVF System

BACKGROUND

Percutaneous devices for creation of native arteriovenous fistulae offer an alternative to traditional open surgical techniques. The 4 Fr WavelinQ EndoAVF System was developed as a lower profile alternative to facilitate access through smaller vessels and minimize access site complications; The current report is the original first experience of this device, assessing outcome in 120 patients followed for 6 months.

METHODS

The use of the 4 Fr WavelinQ system in three studies, EASE (32 patients), EASE-2 (24 patients), and the EU post-market clinical follow-up study (64 patients) was aggregated and analyzed. Patients were followed with duplex ultrasound at discharge and follow-up visits at 1, 3, and 6 months. Primary, assisted primary, and secondary patency rates were evaluated as Kaplan-Meier (KM) estimates and standard errors. Time to maturity and time to successful cannulation were defined as the mean ± SD days from the procedure in patients enrolled on dialysis.

RESULTS

Procedural success was achieved in 116 patients (96.7%). Primary, assisted-primary, and secondary 6-month patency rates were 71.9%±4.5%, 80.7%±4.1%, and 87.8%±3.3%, respectively. Time to maturity averaged 41±17 days. Time to successful cannulation averaged 68±51 days. Device-related serious adverse events were reported in 3/120 patients (2.5%) and procedure-related serious adverse events occurred in 7/120 patients (5.8%). Arterial or venous access complications were not reported in any of the patients. Access circuit reinterventions were performed in 23 patients (19.2%), split between those performed for EndoAVF maturation (13/120, 10.8%) and maintenance (11/120. 9.2%).

CONCLUSIONS

Percutaneous creation of native dialysis fistulae with the 4 Fr WavelinQ EndoAVF System is safe and effective, with favorable durability and a low rate of serious complications and reinterventions through 6-month follow-up. Utilization of the 4F device allows for percutaneous fistula creation between the radial artery and radial vein or the ulnar artery and ulnar vein. These findings suggest that the 4 Fr device is a useful percutaneous alternative to open surgical AVF or endovascular AVF with larger-bore devices.

Study on prediction of arterio-venous fistula maturation by flow mediated dilatation and AVF blood flow

BACKGROUND

The physiology and pathology of AVF maturation depends on the vessels characteristics and its ability to remodel. Outcome of AVF using flow mediated dilatation (FMD), AVF blood flow and diameter has been studied.

METHODOLOGY

Present observational study included single stage AVF (both Radiocephalic and Brachiocephalic) in consecutive CKD five patients (n = 158) prospectively over 1 year. Demographic and Doppler ultrasound parameters of upper limb (for vessel diameter and FMD) at baseline were recorded. Blood flow, diameter and depth of AVF were studied at 2, 6 and 12 weeks and their association with clinical maturation (usage of fistula with two needles for 75% of dialysis sessions during 15 day period) was studied (n = 129, after excluding lost to followup and expired patients; accordingly cohort was divided in matured (M) or non-matured (NM) groups. Clinical and radiological parameters between both groups were compared; receiver operator curve (ROC) and correlation of Doppler parameters were analysed.

RESULTS

Of 129 AVF, 67.4% were matured and 32.5% non-matured. Mean age was 40 years with male predominance75% in both the groups. The mean arterial diameter for distal (NM = 1.96 ± 0.58 and M = 2.02 ± 0.41) and proximal AVF (NM = 3.37 ± 0.82 and M = 3.36 ± 0.75) was not statistically different in both the groups. The matured fistula group had a mean FMD of 11.67 ± 4.09 as against FMD value of 9.365 ± 3.55 in the failed fistula group (p value 0.01). For maturation prediction, sensitivity and specificity of blood flow at 2 weeks were 86.2% and 59.5% and at 6 weeks 96.6% and 64.3%, respectively. In multivariate analysis predictors for AVF maturation were FMD (adjusted odds ratio (AOR) = 1.15) and blood flow (AOR = 1.67).

CONCLUSION

Second and Sixth week AVF blood flow was found to be predicting AVF maturation. Higher baseline FMD correlated with the AVF maturation, but not with vessel diameter.