Hemodialysis vascular access dysfunction: a cellular and molecular viewpoint

Safety and Performance of a Cell-Impermeable Endoprosthesis for Hemodialysis Vascular Access Outflow Stenosis: A Brazilian Multicenter Retrospective Study

PURPOSE

To evaluate the safety and performance of Wrapsody™, a cell-impermeable endoprosthesis (CIE), for treating hemodialysis vascular access outflow stenosis.

MATERIALS AND METHODS

Investigators retrospectively analyzed 113 hemodialysis patients treated with a CIE (11/2021-12/2022) across four centers in Brazil. De novo or restenotic lesions were treated. The primary efficacy outcome measure was target lesion primary patency (TLPP) at 1, 3, 6, and 12 months; the primary safety outcome measure was the absence of serious local or systemic adverse events within the first 30 days post-procedure. Secondary outcome measures included technical and procedural success, access circuit primary patency (ACPP), and secondary patency at 1, 3, 6, and 12 months post-procedure.

RESULTS

Thirty-nine patients (34.5%) had thrombosed access at the initial presentation, and 38 patients (33.6%) presented with recurrent stenosis. TLPP rates at 1, 3, 6, and 12 months were 100%, 96.4%, 86.4%, and 69.7%, respectively. ACPP rates were 100% at 1 month, 89.2% at 3 months, 70.9% at 6 months, and 56.0% at 12 months. The target lesion secondary patency rates at 1, 3, 6, and 12 months were 100%, 97.3%, 93.6%, and 91.7%, respectively. In the adjusted multivariate Cox regression analysis, male sex and endoprosthesis with diameters of 10, 12, 14, and 16 mm were associated with improved primary patency rates. No localized or systemic serious adverse event was observed through the first 30 days post-procedure.

CONCLUSION

The CIE evaluated in this study is safe and effective for treating peripheral and central outflow stenoses in hemodialysis vascular access.

LEVEL OF EVIDENCE

Level 2b, cohort study.

Off-the-Shelf Synthetic Biodegradable Grafts Transform In Situ into a Living Arteriovenous Fistula in a Large Animal Model

Current vascular access options require frequent interventions. In situ tissue engineering (TE) may overcome these limitations by combining the initial success of synthetic grafts with long-term advantages of autologous vessels by using biodegradable grafts that transform into autologous vascular tissue at the site of implantation. Scaffolds (6 mm-Ø) made of supramolecular polycarbonate-bisurea (PC-BU), with a polycaprolactone (PCL) anti-kinking-coil, are implanted between the carotid artery and jugular vein in goats. A subset is bio-functionalized using bisurea-modified-Stromal cell-derived factor-1α (SDF1α) derived peptides and ePTFE grafts as controls. Grafts are explanted after 1 and 3 months, and evaluated for material degradation, tissue formation, compliance, and patency. At 3 months, the scaffold is resorbed and replaced by vascular neo-tissue, including elastin, contractile markers, and endothelial lining. No dilations, ruptures, or aneurysms are observed and grafts are successfully cannulated at termination. SDF-1α-peptide-biofunctionalization does not influence outcomes. Patency is lower in TE grafts (50%) compared to controls (100% patency), predominantly caused by intimal hyperplasia. Rapid remodeling of a synthetic, biodegradable vascular scaffold into a living, compliant arteriovenous fistula is demonstrated in a large animal model. Despite lower patency compared to ePTFE, transformation into autologous and compliant living tissue with self-healing capacity may have long-term advantages.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Comparison between the 0- and 30-s balloon dilation time in percutaneous transluminal angioplasty for restenosed arteriovenous fistula among hemodialysis patients: a multicenter, prospective, randomized trial (CARP study)

BACKGROUND

This study aims to compare patency rates of the 0- and 30-s (sec) balloon dilation time in hemodialysis (HD) patients with restenosis after percutaneous transluminal angioplasty (PTA).

METHODS

The patients who underwent PTA within 6 months for failed arteriovenous fistula at the forearm were randomly assigned the 0-s or 30-s dilation time group. Effect of dilation time on the 3- and 6-month patency rates after PTA was examined.

RESULTS

Fifty patients were enrolled in this study. The 3-month patency rate in the 30-s dilation group was better than that in the 0-s dilation group (P = 0.0050), while the 6-month patency rates did not show a significant difference between the two groups (P = 0.28). Cox's proportional hazard model revealed that 30-s of inflation time (hazard ratio 0.027; P = 0.0072), diameter of the proximal (hazard ratio 0.32; P = 0.031), and dilation pressure (hazard ratio 0.63; P = 0.014) were associated with better 3-month patency. Dilation pressure between previous and present PTA did not differ in the 0-s (P = 0.15) and 30-s dilation groups (P = 0.16). The 6-month patency rate of the present PTA in the 30-s dilation group was higher than that of the previous PTA (P = 0.015). The visual analog scale did not differ between the two groups (P = 0.51).

CONCLUSION

The presenting data suggest that 30-s dilation potentially results in a better 3-month patency rate than 0-s dilation in HD patients with restenosis after PTA.

Application of modified no-touch technique in rabbit arteriovenous fistula model and its effect on venous neointimal hyperplasia

BACKGROUND

To investigate the technical advantages of a modified no-touch technique (MNTT) in constructing arteriovenous fistulas (AVF) compared to the conventional technique (CT) and assess its potential to reduce neointimal hyperplasia in the outflow vein.

METHODS

Forty-seven New Zealand rabbits were randomly divided into three groups: control, CT, and MNTT. Rabbits in control group were observed using ultrasound and then euthanized to obtain external jugular vein (EJV) for Hematoxylin-eosin (H-E). We established common carotid artery (CCA)-EJV AVF using MNTT in the MNTT group and the CT in the CT group. AVF patency and complications were compared between the CT and MNTT groups. Rabbits with patent AVF in both groups were observed using ultrasound 2 weeks after surgery to evaluate changes in the vessel diameter and blood flow spectrum of the AVFs. H-E staining measured the intima thickness of EJV adjacent to the anastomosis and histologic characteristics of the AVF at 2 and 4 weeks after surgery.

RESULTS

Five rabbits died after surgery with common symptoms of sneezing, coughing, runny nose, anorexia, and diarrhea; two in the MNTT group and three in the CT group. There were significant differences in the diameter (p = 0.010) and peak systolic velocities (PSV) (p = 0.001) of EJV between the CT and MNTT groups 2 weeks after surgery. Spiral laminar flow (SLF) was observed in CCA and EJV adjacent to anastomosis in the MNTT group. Additionally, histological observations showed less venous neointimal hyperplasia in the MNTT group than in the CT group 4 weeks after surgery.

CONCLUSION

The rabbit model of CCA-EJV AVF established using MNTT demonstrated fewer complications, larger vein diameters, and reduced venous neointimal hyperplasia, indicating that this maybe an ideal animal model to further investigate the application of MNTT in AVF surgery.

Patients, healthcare providers, and general population preferences for hemodialysis vascular access: a discrete choice experiment

Background

A patient-centered dialysis treatment option requires an understanding of patient preferences for alternative vascular accesses and nephrologists often face difficulties when recommending vascular access to end-stage kidney disease (ESKD) patients. We aimed to quantify the relative importance of various vascular access characteristics to patients, healthcare providers and general population, and how they affect acceptability for patients and healthcare providers.

Methods

In a discrete choice experiment, patients with maintenance hemodialysis (MHD), healthcare providers, and individuals from the general population were invited to respond to a series of hypothetical vascular access scenarios that differed in five attributes: cumulative patency, infection rate, thrombosis rate, cost, and time to maturation. We estimated the respondents' preference heterogeneity and relative importance of the attributes with a mixed logit model (MXL) and predicted the willingness to pay (WTP) of respondents via a multinomial logit model (MNL).

Results

Healthcare providers (n = 316) and the general population (n = 268) exhibited a favorable inclination toward longer cumulative patency, lower access infection rate and lower access thrombosis rate. In contrast, the patients (n = 253) showed a preference for a 3-year cumulative patency, 8% access infection rate, 35% access thrombosis rate and 1.5 access maturity time, with only the 3-year cumulative patency reaching statistical significance. Among the three respondent groups, the general population found cumulative patency less important than healthcare providers and patients did. Patients demonstrated the highest WTP for cumulative patency, indicating a willingness to pay an extra RMB$24,720(US$3,708) for each additional year of patency time.

Conclusion

Patients and healthcare providers had a strong preference for vascular access with superior patency. While the general population preferred vascular access with lower thrombosis rates. These results indicate that most patients prefer autogenous arteriovenous fistula (AVF) as an appropriate choice for vascular access due to its superior patency and lower complications than other vascular access types.

The predictive value of systemic inflammatory markers in 902 patients with tunneled hemodialysis catheter

AIM

This study aimed to assess the predictive role of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and mean platelet volume, on catheter survival in chronic hemodialysis patients, analyzing both infectious and non-infectious complications.

METHODS

A retrospective analysis encompassed 1279 tunneled catheter insertion procedures involving 902 patients between March 2014 and October 2018. Patients were categorized into two main groups: (i) initial placement and (ii) exchange. The exchange group was further stratified into four subgroups: infection, dysfunction, displacement, and transitioning temporary hemodialysis catheters to long-term ones. Hematologic ratios were calculated from baseline hemogram data, including neutrophil, lymphocyte, monocyte, and platelet counts, while mean platelet volume was derived from the same hemogram.

RESULTS

The patients in the exchange group displayed significantly higher lymphocyte and monocyte values (p < 0.001), while lower values were noted for neutrophil-lymphocyte ratio and platelet-lymphocyte ratio (p < 0.001). The transition group displayed higher monocyte values and lower mean platelet volume and lymphocyte-monocyte ratio values (p < 0.05). In the infection-related exchange subgroup, higher neutrophil count, mean platelet volume, neutrophil-lymphocyte ratio, and platelet-lymphocyte ratio values were observed compared to other groups (p < 0.05). Cases related to catheter dysfunction exhibited increased lymphocyte-monocyte ratio but lower neutrophil, monocyte, neutrophil-lymphocyte ratio, and platelet-lymphocyte ratio values (p < 0.05).

CONCLUSION

This study highlights the interest of specific inflammatory markers, particularly monocytes, neutrophil-lymphocyte ratio, and platelet-lymphocyte ratio, in the management of tunneled catheters, notably in patients undergoing exchanges. However, cut-off values, essential for constructing management algorithms, are currently lacking, and prospective multicenter studies are needed for further elucidation.

Periadventitial biomaterials to improve arteriovenous fistula and graft outcomes

Periadventitial biomaterials have been employed for nearly three decades to promote adaptive venous remodeling following hemodialysis vascular access creation in preclinical models and clinical trials. These systems are predicated on the combination of scaffolds, hydrogels, and/or particles with therapeutics (small molecules, proteins, genes, and cells) to prevent venous stenosis and subsequent maturation failure. Periadventitial biomaterial therapies have evolved from simple drug delivery vehicles for traditional drugs to more thoughtful designs tailored to the pathophysiology of access failure. The emergence of tissue engineering strategies and gene therapies are another exciting new direction. Despite favorable results in experimental and preclinical studies, no periadventitial therapy has been clinically approved to improve vascular access outcomes. After conducting an exhaustive review of the literature, we identify the seminal studies and clinical trials that utilize periadventitial biomaterials and discuss the key features of each biomaterial format and their respective shortcomings as they pertain to access maturation. This review provides a foundation from which clinicians, surgeons, biologists, and engineers can refer to and will hopefully inspire thoughtful, translatable treatments to finally address access failure.

Arteriovenous Access for Hemodialysis: A Review

Importance

Hemodialysis requires reliable vascular access to the patient's blood circulation, such as an arteriovenous access in the form of an autogenous arteriovenous fistula or nonautogenous arteriovenous graft. This Review addresses key issues associated with the construction and maintenance of hemodialysis arteriovenous access.

Observations

All patients with kidney failure should have an individualized strategy (known as Patient Life-Plan, Access Needs, or PLAN) for kidney replacement therapy and dialysis access, including contingency plans for access failure. Patients should be referred for hemodialysis access when their estimated glomerular filtration rate progressively decreases to 15 to 20 mL/min, or when their peritoneal dialysis, kidney transplant, or current vascular access is failing. Patients with chronic kidney disease should limit or avoid vascular procedures that may complicate future arteriovenous access, such as antecubital venipuncture or peripheral insertion of central catheters. Autogenous arteriovenous fistulas require 3 to 6 months to mature, whereas standard arteriovenous grafts can be used 2 to 4 weeks after being established, and "early-cannulation" grafts can be used within 24 to 72 hours of creation. The prime pathologic lesion of flow-related complications of arteriovenous access is intimal hyperplasia within the arteriovenous access that can lead to stenosis, maturation failure (33%-62% at 6 months), or poor patency (60%-63% at 2 years) and suboptimal dialysis. Nonflow complications such as access-related hand ischemia ("steal syndrome"; 1%-8% of patients) and arteriovenous access infection require timely identification and treatment. An arteriovenous access at high risk of hemorrhaging is a surgical emergency.

Conclusions and Relevance

The selection, creation, and maintenance of arteriovenous access for hemodialysis vascular access is critical for patients with kidney failure. Generalist clinicians play an important role in protecting current and future arteriovenous access; identifying arteriovenous access complications such as infection, steal syndrome, and high-output cardiac failure; and making timely referrals to facilitate arteriovenous access creation and treatment of arteriovenous access complications.

Stenosis to stented: decrease in flow disturbances following stent implantation of a diseased arteriovenous fistula

The arteriovenous fistula (AVF) is commonly faced with stenosis at the juxta-anastomotic (JXA) region of the vein. Implantation of a flexible nitinol stent across the stenosed JXA has led to the retention of functioning AVFs leading to the resulting AVF geometry being distinctly altered, thereby affecting the haemodynamic environment within it. In this study, large eddy simulations of the flow field within a patient-specific AVF geometry before and after stent implantation were conducted to detail the change in flow features. Although the diseased AVF had much lower flow rates, adverse flow features, such as recirculation zones and swirling flow at the anastomosis, and jet flow at the stenosis site were present. Larger velocity fluctuations (leading to higher turbulent kinetic energy) stemming from these flow features were apparent in the diseased AVF compared to the stented AVF. The unsteadiness at the stenosis created large regions of wall shear stress (WSS) fluctuations downstream of the stenosis site that were not as apparent in the stented AVF geometry. The larger pressure drop across the diseased vein, compared to the stented vein, was primarily caused by the constriction at the stenosis, potentially causing the lower flow rate. Furthermore, the WSS fluctuations in the diseased AVF could lead to further disease progression downstream of the stenosis. The change in bulk flow unsteadiness, pressure drop, and WSS behaviour confirms that the haemodynamic environment of the diseased AVF has substantially improved following the flexible stent implantation.

CEUS-guided PTA on stenotic AVF: Morphological and functional point of view

BACKGROUND

Stenosis represents the main cause of hemodialysis fistula malfunction. The ultrasound-guided angioplasty with ecographic contrast (CEUS) could provide further advantages to the classical ultrasound guided method improving the morphological characterization of the stenosis and providing quantitative data with the creation of time intensity curves (TIC) collecting functional data comparable between pre and post procedure.

METHODS

A total of 10 CEUS-guided angioplasties were performed on malfunctioning fistulas. The sonographic contrast medium was injected into the vascular tree trough the introducer. Morphological and functional data nature were collected. Were generated TIC curves, obtained by positioning a ROI in correspondence with the post-stenotic tract of the efferent vein. The data collected, regarding the peak intensity reached by the signal (PI) and the time to reach the peak signal intensity (TTP), were compared in the pre and post-procedural phase with flow of vascular access (Qa) and resistance indices (RI).

RESULTS

Statistically significant correlation (p < 0.05) was observed between Qa and TTP (r = 0.77; p = 0.009), RI and TTP (r = 0.71; p = 0.02), Qa and PI (r = 0.86; p = 0.0012), and between RI and PI (r = 0.88; p < 0.001).

CONCLUSION

In addition to the advantages associated with the use of ultrasound contrast medium in improving the visualization and characterization of the stenosis by facilitating the PTA procedure, the functional data deriving from the quantitative analysis provide new parameters for evaluating the success of the procedure which could also be used as predictive markers of stenosis recurrence together with the classical ones.

Hemodialysis patients and complications management costs in Italy: Plastic cannulae a potentially cost-effective strategy

BACKGROUND

The treatment of end-stage chronic renal failure involves substantial costs for health care, which could be higher considering hemodialysis access complications management costs. Complications could be addressed by cannulation technique, but also by the needle. In particular, the use of a metal needle for cannulation is responsible for several complications that compromise dialysis delivery and require interventions. This analysis aims to evaluate, from a hospital perspective, the direct costs related to complications that may occur in hemodialysis patients in Italy.

METHODS

To identify the main complications to consider in our analysis and related patient pathway for their management, we conducted an international literature search on PubMed and validated the data for Italy with an Italian Key Opinion Leader (KOL). A micro-costing analysis was developed to precisely assess the economic costs of healthcare interventions to manage complications due to vascular access cannulation.

RESULTS

The major complications identified, and the average cost/per episode for their management are the following ones: Local infection € 1455 (min € 745 and max € 2160); Sepsis, that requires hospitalization in ward € 4401 (min € 3693 and max € 4623); Sepsis (ICU) € 17,190; Hematoma € 304 (min € 252 and max € 728); Aneurysm € 3632 (min € 3139 and max € 4014); Pseudoaneurysm € 3695 (min € 3615 and max € 4014); Stenosis € 2229 (min € 1874 and max € 4857); Thrombosis € 2151 (min € 1941 and max € 3395).

CONCLUSIONS

In making decisions, hospital administration, and payer should take into consideration, not just the price of devices, but the entire patient's pathway. The use of plastic cannulae in hemodialysis patients shows improved outcomes compared to traditional metal needles. Furthermore, combining it with accurate and efficient cannulation techniques reduces complication rates, improves patients' quality of life, and reduces healthcare resource consumption.

Effect of two different techniques of arteriovenous fistula puncture on wound infection in haemodialysis patients

Safe and effective arteriovenous fistula (AVF) puncture is very important to reduce the wound complications of haemodialysis (HD). For AVF puncture in dialysis patients, there is a lack of clarity and consistency regarding the relative advantage of buttonhole (BH) over rope-ladder (RL) cannulae in terms of wound complications. The study was published in several scientific databases including Cochrane Library, PubMed and Embase by October 2023. Data from all controlled trials looking at the effect of BH and RL on wound complications in haemodialysis patients were included. The articles were written in English, and they were about adult who had AVF while on dialysis. Studies with or without BH or RL treatment were excluded from the analysis. The data was analysed with RevMan5.3 software. Out of 215 trials, 9 were chosen for the final analysis. The study publication dates were between 2000 and 2023. Of these, 17 326 patients received AVF therapy. Among them, there were 3070 BH and 14 256 RL. In 9 studies, RL had a lower risk of postoperative wound infection compared to BH (OR, 3.38; 95% CI, 3.06, 3.73 p < 0.0001); In all 3 studies, there were no statistically significant differences in the risk of post operative bleeding in RL versus BH(OR, 0.76; 95% CI, 0.25, 2.33 p = 0.63). Our studies have demonstrated that RL trocars are superior to BH trocars in the prevention of wound infection.

Safety and efficacy of a new covered stent in hemodialysis vascular access outflow stenosis: A Brazilian multicenter retrospective study

BACKGROUND

Vascular stenosis commonly leads to dysfunction in hemodialysis vascular access. Although percutaneous transluminal angioplasty is an established treatment, stent utilization has increased in the last decade as an alternative solution to extend the access function. This study evaluated the safety and initial results of a new impermeable covered stent for treating vascular access outflow stenosis.

METHODS

Investigators retrospectively analyzed 114 hemodialysis patients treated with polytetrafluorethylene-covered stents from September 2018 to September 2022 across four centers. Lesions treated were de novo or restenotic and located in the venous graft anastomosis, outflow segment, cephalic arch, and basilic swing point. Patients were followed by in-person physical examination at 1, 3, and 6 months, and Duplex ultrasound was performed to evaluate the vascular access circuit and in-stent restenosis. The primary efficacy endpoint was target lesion primary patency at 1, 3, and 6 months. Secondary endpoints included access circuit primary patency and secondary patency at 1, 3, and 6 months. The primary safety endpoint was freedom from local or systemic serious adverse events through 30 days post-procedure.

RESULTS

Forty-four patients had thrombosed access at the initial presentation, and 41 patients presented with recurrent stenosis. The target lesion primary patency rates at 1, 3, and 6 months were 100%, 89.4%, and 74%, respectively. The access circuit primary patency rates were 100% at 1 month, 85% at 3 months, and 62.7% at 6 months. The secondary patency rates at 1, 3, and 6 months were 100%, 96.4%, and 94.6%, respectively. In the adjusted multivariate Cox regression analysis, only recurrent lesions and female gender were associated with reduced primary patency rates. No serious adverse event was observed through the first 30 days post-procedure.

CONCLUSION

In this retrospective analysis, a new covered stent was shown to be safe and effective for treating peripheral outflow stenosis in vascular access.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

ADVANCES IN KNOWLEDGE

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

The rodent models of arteriovenous fistula

Arteriovenous fistulas (AVFs) have long been used as dialysis access in patients with end-stage renal disease; however, their maturation and long-term patency still fall short of clinical needs. Rodent models are irreplaceable to facilitate the study of mechanisms and provide reliable insights into clinical problems. The ideal rodent AVF model recapitulates the major features and pathology of human disease as closely as possible, and pre-induction of the uremic milieu is an important addition to AVF failure studies. Herein, we review different surgical methods used so far to create AVF in rodents, including surgical suturing, needle puncture, and the cuff technique. We also summarize commonly used evaluations after AVF placement. The aim was to provide recent advances and ideas for better selection and induction of rodent AVF models. At the same time, further improvements in the models and a deeper understanding of AVF failure mechanisms are expected.

Comparison of Lower and Upper Extremity Arteriovenous Graft: A Retrospective Clinical Analysis with 5-Year Follow-Up

BACKGROUND

For patients in whom an upper extremity (UE) vascular access cannot be established, the lower extremity (LE) arteriovenous graft (AVG) could be selected. However, the application of LE AVG is limited owing to its high infection rate, uncertain patency time, and technical difficulties. This study aimed to compare the long-term patency rates and the incidence of vascular access complications of AVG in the LE and UE to provide a reference for the applications of AVG, especially in the LEs.

METHODS

This was a retrospective analysis of patients who successfully underwent LE or UE AVG placement from March 2016 to October 2021. Patient characteristics were collected and compared using parameter or nonparameter tests according to data type. Postoperative patency was evaluated using Kaplan-Meier test. Postoperative complication incidence density and intergroup comparison were estimated using the Poisson distribution.

RESULTS

Twenty-two patients with LE AVG and 120 patients with UE AVG were included. The 1-year primary patency rate was 67.4% (±11.0% standard error [SE]) in the LE group and 30.1% (±4.5% SE) in the UE group (P = 0.031). The assisted primary patency rate at postoperative months 12, 24, and 36 was respectively 78.6% (±9.6% SE), 65.5% (±14.4% SE), and 49.1% (±17.8% SE) in the LE group and 63.3% (±4.6% SE), 47.5% (±5.4% SE), and 30.4% (±6.1% SE) in the UE group (P = 0.137). The secondary patency rate at postoperative months 12, 24, and 36 remains 95.5% (±4.4% SE) in the LE group and 89.3% (±2.9% SE), 83.7% (±3.9% SE), and 73.0% (±6.2% SE), respectively, in the UE group (P = 0.200). Postoperative complications included stenosis, occlusion/thrombosis, infection, steal syndrome, pseudoaneurysm, severe postoperative serum swelling, and AVG exposure. The total incidence rates of postoperative complications were 0.87 (95% confidence interval [CI] 0.59-1.23) versus 1.61 (95% CI 1.45-1.79) (P = 0.001) cases/person-year, the incidence rates of stenosis were 0.45 (95% CI 0.26-0.73) versus 0.92 (95% CI 0.80-1.06) (P = 0.005) cases/person-year and the incidence rates of occlusion/thrombosis were 0.34 (95% CI 0.17-0.59) versus 0.62 (95% CI 0.52-0.74) cases/person-year in the LE group compared to those in the UE group (P = 0.041).

CONCLUSIONS

LE AVG had higher primary patency rate and lower postoperative complication incidence than UE AVG. With the development of interventional technology, both LE AVG and UE AVG exhibited high secondary patency rates. LE AVG can be a reliable and long-term alternative for appropriately selected patients with unusable UE vessels.

Treatment of intragraft stenosis in hemodialysis grafts with Supera stents: A retrospective study

PURPOSE

To report the patency rates after implantation of an interwoven nitinol stent to salvage failing arteriovenous grafts (AVGs) caused by intragraft stenoses.

METHODS

Between May 2018 and May 2020, 21 Supera stents were placed in 20 patients (18 women; mean age: 79.9 years) who had a failing AVG due to repeat intragraft stenoses. Recurrent AVG dysfunction with same intragraft stenosis within 3 months after first time angioplasty was a criterion for stenting. Those with concurrent treatment for other lesions were excluded.

RESULTS

The technical success rate was 100%. Intragraft stenoses were treated at a median of 19.7 (interquartile range: 6-36) months after graft creation. Access circuit primary patency rates after stent placement were 84% and 35% at 6 and 12 months, respectively. Access circuit secondary patency rates were 100% at 6 and 12 months and 89% at 18 months. Only one patient presented with graft failure due to proximal drainage vein occlusion. The target lesion patency rates were 100% at 6 months and 75% at 12 months. The rate of reintervention for intragraft lesion was 0.15 procedures per year. Stent distortion did not occur under regular cannulation.

CONCLUSION

The interwoven nitinol stent is a promising treatment for failing AVGs with recurrent intragraft stenoses. The 1-year access circuit primary, secondary, and target lesion patency rates were acceptable, with a low reintervention rate. Stent fracture does not occur in areas of needle puncture.

Risk factors for arteriovenous fistula dysfunction in hemodialysis patients: a retrospective study

Arteriovenous fistula (AVF) is the first choice of vascular access in hemodialysis (HD) patients. However, the correlations between patient factors and the arteriovenous fistula patency remain unclear. Therefore, our study investigates the risk factors associated with AVF dysfunction in HD patients. A total of 233 end-stage renal disease (ESDR) patients who met the study inclusion criteria in the Nephrology Department of Hunan Provincial People's Hospital between December 2020 and June 2022 were included in this study. The baseline demographic, clinical and laboratory parameters were collected at the time of AVF creation and analyzed. Of the 233 ESRD patients, 146 (62.7%) were male and the mean age was 56.11 ± 12.14 (21-82) years. The patients were followed for a median time of 14 months. Kaplan-Meier analysis showed a 6-, 12- and 24-month post-placement survival of 87.1%, 82.8% and 80.7%, respectively. Univariate Cox regression analysis revealed weight (HR, 1.03; P = 0.03) as a predictor for the loss of vascular access functionality. In addition, multivariate Cox regression analysis further demonstrated that sex (HR, 3.41; P = 0.03), weight (HR 1.08; P < 0.01) and phosphorus level (HR: 3.03; P = 0.01) are independent risk factors for AVF dysfunction. AVF dysfunction is highly associated with several risk factors including weight, phosphorus level, and sex. Positive intervention strategies targeting these potential factors, such as weight loss or oral phosphate binders could improve the long-term success of AVF.

Exosomal miRNA-200b-3p regulated autogenous arteriovenous fistula thrombosis in maintenance hemodialysis patients

BACKGROUND

Autogenous arteriovenous fistula (AVF) is the best vascular hemodialysis access for terminal chronic renal failure patients but is prone to thrombosis. Pathogenic mechanisms of AVF thrombus are thus largely explored. As exosomes carry genetic content from cell of origin. We hypothesized that miRNAs in serum exosomes are promising regulators of AVF thrombosis.

METHODS

Serum exosomes were isolated from maintenance hemodialysis (MHD) patient, miRNAs profile of the exosomes was obtained by high throughput sequencing, six miRNAs (miR-144-5p, miR-18a-5p, miR-200a-3p, miR-200b-3p, miR-141-3p, and miR-429) were determined as candidates examined by RT-PCR, cells transfected with miR-200b-3p mimics demonstrated significantly increased mRNA levels of VEGF and Ang-II, the relationship between miR-200b-3p and VEGF or Ang-II was performed by adual luciferase reporter assay.

RESULTS

There are 43 miRNA down-regulation and 15 miRNA up-regulation between MHD group and MHD+Thrombus group, the expression levels of miR-200b-3p and miR-429 in MHD with thrombus were significantly increased (p < 0.001, p < 0.05). Inhibited miR-200b-3p expression level can increase VEGF mRNA and protein expression levels and decrease Ang-II mRNA and protein expression levels. Furthermore, we also identified that miR-200b-3p targets VEGF and Ang-II.

CONCLUSION

Our study indicates that serum exosome-derived miR-200b-3p regulate VEGF and Ang-II to increase intimal hyperplasia to induce AVF thrombosis. Besides miR-200b-3p, miR-200 family may also play a regulatory role in AVF thrombosis.

Role of neutrophil extracellular traps in vascular access thrombosis in hemodialysis patients

BACKGROUND

A patent vascular access (VA) is a lifeline for hemodialysis (HD) patients. However, vascular access is prone to thrombosis, which, if left untreated, can lead to permanent VA loss and increased mortality. Neutrophil extracellular traps (NETs) are known to be involved in intravascular thrombosis. We evaluated the relationship between NETs and VA thrombosis and their impact on VA prognosis.

METHODS

A total of 189 patients with VA flow problems were enrolled. Among these, 93 patients underwent percutaneous transluminal angioplasty (PTA) for stenosis, and 96 patients underwent PTA with thrombectomy for thrombosis. Plasma nucleosome, myeloperoxidase-DNA complex, and von Willebrand factor (vWF) were measured as markers of circulating NETs and thrombosis risk, respectively. The primary outcome was permanent VA loss and the secondary outcome was recurrent thrombotic occlusion within 6 months. In addition, the presence of NETs in thrombi was evaluated by histopathological analysis.

RESULTS

Circulating nucleosome levels were closely associated with plasma vWF levels (r = 0.172, p = 0.025), and both were higher in thrombectomy cases than in PTA alone cases (nucleosome; 0.83 ± 0.70 vs. 0.35 ± 0.26, p < 0.001, vWF: 9.0 ± 7.6 vs. 7.3 ± 6.2, p = 0.038). The highest quartile of nucleosomes (Q4) was associated with an 18-fold increased rate of access thrombotic occlusion (p < 0.001). In addition, multivariate analysis showed that the rates of permanent access loss (HR 2.77, 95 % CI 1.35-5.77) and recurrent thrombosis (HR 2.35, 95 % CI 1.22-4.54) were much higher in patients with the Q4 nucleosome group than in those with Q1-3. In addition, higher neutrophil infiltration and NET expression in thrombi were also associated with poor VA prognosis.

CONCLUSIONS

Higher levels of circulating NETs and the amount of NET expression in thrombi may be associated with VA thrombosis and poor VA outcomes.

A bio-instructive parylene-based conformal coating suppresses thrombosis and intimal hyperplasia of implantable vascular devices

Implantable vascular devices are widely used in clinical treatments for various vascular diseases. However, current approved clinical implantable vascular devices generally have high failure rates primarily due to their surface lacking inherent functional endothelium. Here, inspired by the pathological mechanisms of vascular device failure and physiological functions of native endothelium, we developed a new generation of bioactive parylene (poly(p-xylylene))-based conformal coating to address these challenges of the vascular devices. This coating used a polyethylene glycol (PEG) linker to introduce an endothelial progenitor cell (EPC) specific binding ligand LXW7 (cGRGDdvc) onto the vascular devices for preventing platelet adhesion and selectively capturing endogenous EPCs. Also, we confirmed the long-term stability and function of this coating in human serum. Using two vascular disease-related large animal models, a porcine carotid artery interposition model and a porcine carotid artery-jugular vein arteriovenous graft model, we demonstrated that this coating enabled rapid generation of self-renewable "living" endothelium on the blood contacting surface of the expanded polytetrafluoroethylene (ePTFE) grafts after implantation. We expect this easy-to-apply conformal coating will present a promising avenue to engineer surface properties of "off-the-shelf" implantable vascular devices for long-lasting performance in the clinical settings.

Cannulation Technique of Vascular Access in Hemodialysis and the Impact on the Arteriovenous Fistula Survival: Systematic Review and Meta-Analysis

Adequate cannulation technique (CT) methods and successful puncture are essential for hemodialysis (HD) and arteriovenous fistula (AVF) maintenance. This systematic review and meta-analysis was designed to identify which CT allows better AVF primary patency and lower rates of complications in HD patients. The search was carried out on the CINAHL, MEDLINE, Cochrane Library, and Joanna Briggs Institute Library databases to identify all randomized controlled trials (RCTs) and observational studies comparing clinical outcomes of buttonhole (BH) versus rope ladder cannulation (RL) from 2010 to 2022. The Risk-of-Bias (Rob 2) tool was used for RCTs and the ROBINS-I was used for non-randomized studies. RevMan 5.4 was used for the meta-analysis. A total of five RCTs, one quasi-randomized controlled trial, and six observational studies were included. When compared with RL cannulation, BH cannulation significantly increased bacteremia (RR, 2.76, 95% CI (1.14, 6.67), p = 0.02) but showed no differences in AVF primary patency (HR, 1.06, 95% CI (0.45, 4.21), p = 0.90). There was no thrombosis reduction (RR, 0.51, 95% CI (0.23, 1.14), p = 0.10) or intervention number reduction (RR, 0.93, 95% CI (0.49, 1.80), p = 0.84) with BH. Outcomes like pain, hematoma, and aneurism could not be merged due to a lack of data, reported as medians, as well as due to different definitions. The quality in general was poor and the heterogeneity among the studies prevented us from merging the outcomes.

The Role of Drug-Coated Balloon in Haemodialysis Arteriovenous Fistula Stenosis Management

Arteriovenous fistula (AVF) stenosis is a common problem leading to dialysis access dysfunction. The conventional balloon (CB) is the most commonly used device during angioplasty but suffers from poor durability of results due to neointimal hyperplasia-mediated recurrence. The drug-coated balloon (DCB) is an adjunct to balloon angioplasty that reduces neointimal hyperplasia, thereby improving post-angioplasty patency. Despite the heterogeneity of DCB clinical trials to date, the evidence suggests that DCBs of different brands are not necessarily equal, and that patient selection, adequate lesion preparation and proper DCB procedural technique are important to realize the benefit of DCB angioplasty.

Endovascular salvage of failing arterio-venous fistulas utilising sirolimus eluting balloons: Six months results from the ISABELLA trial

BACKGROUND

Aim of this pilot clinical study was to evaluate the safety and efficacy of the Selution Sustained Limus Release (SLR)™ sirolimus-eluting balloon (SEB) for improving failing arterio-venous fistulas (AVF) patency in Asian haemodialysis patients.

METHODS

Prospective single-centre, multi-investigator, non-consecutive, non-blinded single arm trial. Forty end-stage renal failure Asian patients with a dysfunctional AVF underwent SEB angioplasty between May and November 2020. All stenotic lesions were prepared with high pressure non-compliant balloon angioplasty prior to SEB angioplasty. Endpoints of interest included target lesion primary patency and circuit access patency and safety through 30 days. All patients received dual antiplatelet therapy for 1 month and were followed up with Duplex ultrasound at 6 months.

RESULTS

There was one subject dropout so final n = 39 patients (mean age 65.0 ± 11.9; males = 26 (66.7%)) and n = 43 target lesions treated. Main indication for intervention was dropping access flow (24/39; 61.5%) and most common target lesion was in the juxta-anastomosis (24/43; 54.5%). There was 100% technical and procedural success. There were no adverse events related to the SEB. Target lesion primary patency rates at 3 and 6 months were 39/41 (95.1%) and 28/39 (71.8%) respectively. Access circuit patency rates at 3 and 6 months were 35/37 (94.6%) and 22/35 (62.9%) respectively. There were 3 (7.7%) deaths all attributable to patients' underlying co-morbidities.

CONCLUSIONS

Fistuloplasty using the novel Selution SLR™ SEB for dysfunctional AVF circuits seems a safe and effective modality in Asian haemodialysis patients at 6 months but larger randomised controlled studies are required now to determine its true efficacy against plain balloon angioplasty.

Health care disparities involved in establishing functional arteriovenous fistula hemodialysis access

OBJECTIVE

Race-related disparities in outcomes associated with cardiovascular disease are well-documented. Arteriovenous fistula (AVF) maturation can be a challenge in establishing functional access in the population of patients with end-stage renal disease requiring hemodialysis. We sought to investigate the incidence of adjunctive procedures required to establish fistula maturation and evaluate the association with demographic factors including patient race.

METHODS

This study was a single-institution retrospective review of patients undergoing first-time AVF creation for hemodialysis from January 1, 2007, to December 31, 2021. Subsequent arteriovenous access interventions, such as percutaneous angioplasty, fistula superficialization, branch ligation and embolization, surgical revision, and thrombectomy, were recorded. The total number of interventions performed after index operation was recorded. Demographic data including age, sex, race, and ethnicity was recorded. The need for and number of subsequent interventions was evaluated using multivariable analysis.

RESULTS

A total of 669 patients were included in this study. Patients were 60.8% male and 39.2% female. Race was reported as White in 329 (49.2%), Black in 211 (31.5%), Asian in 27 (4.0%), and other/unknown in 102 (15.3%). Of the patients, 355 (53.1%) underwent no additional procedures after initial AVF creation, 188 (28.1%) underwent one additional procedure, 73 (10.9%) had two additional procedures, and 53 (7.9%) had three or more additional procedures. As compared with the White reference group, Black patients were at higher risk of having maintenance interventions (relative risk [RR], 1.900; P ≤ .0001) and additional AVF creation interventions (RR, 1.332; P = .05), and total interventions (RR, 1.551; P ≤ .0001).

CONCLUSIONS

Black patients were at significantly higher risk of undergoing additional surgical procedures, including both maintenance and new fistula creations, as compared with their counterparts of other racial groups. Further exploration of the root cause of these disparities is necessary to facilitate the achievement of equivalent high-quality outcomes across racial groups.

Impact of preoperative exercise in not initially candidates to native arteriovenous fistulas

BACKGROUND

Native autologous arteriovenous fistula (AVFn) is the preferred vascular access for hemodialysis due to its long term patency and low complication rate. A challenging limitation is the anatomical inability to perform AVFn and failure of maturation. Preoperative isometric exercise (PIE) can increase vascular calibers and improve the rate of distal AVF. However, it is unknown whether PIE might enhance the performance of AVFn in patients who are not initially candidates.

METHODS

A retrospective observational study was conducted over a population of 45 patients evaluated in vascular access clinic, 23 were not initially candidates for radiocephalic (NRC-AVF) and 22 were not candidates for autologous fistula at all (NA-AVF). They were assigned to perform PIE with handgrip device and revaluated.

RESULTS

After 4-8 weeks of PIE, a AVFn was performed in 16 patients from NA-AVF group and a radiocephalic AVFn was performed in 21 patients from NRC-AVF group. Both groups experienced a significant and similar increase in venous caliber 0.91 ± 0.43 mm in NA-AVF versus 0.76 ± 0.47 mm in NRC-AVF (p = 0.336) and arterial caliber 0.18 ± 0.24 mm versus 0.18 ± 0.21 mm (p = 0.928), respectively. Nevertheless, primary failure rate was significantly higher in NA-AVF (n = 8, 50%) than in NRC-AVF group (n = 3, 14.3%) (p = 0.030). After 6 months, the fistula usability for dialysis was only 50% in NA-AVF, while 86.7% were dialyzed by fistula in NRC-AVF group (p = 0.038).

CONCLUSIONS

PIE allowed the allocation of an AVFn in patients not initially candidates, but entailed a high rate of maturation failure. Patients not candidates to radiocephalic AVF benefited from PIE and preserved a long term usability of AVF for dialysis.

Fate mapping RNA-sequencing reveal Malat1 regulates Sca1+ progenitor cells to vascular smooth muscle cells transition in vascular remodeling

Regeneration of smooth muscle cells (SMCs) is vital in vascular remodeling. Sca1⁺ stem/progenitor cells (SPCs) can generate de novo smooth muscle cells after severe vascular injury during vessel repair and regeneration. However, the underlying mechanisms have not been conclusively determined. Here, we reported that lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (Malat1) was down-regulated in various vascular diseases including arteriovenous fistula, artery injury and atherosclerosis. Using genetic lineage tracing mice and veingraft mice surgery model, we found that suppression of lncRNA Malat1 promoted Sca1⁺ cells to differentiate into SMCs in vivo, resulting in excess SMC accumulation in neointima and vessel stenosis. Genetic ablation of Sca1⁺ cells attenuated venous arterialization and impaired vascular structure normalization, and thus, resulting in less Malat1 down-regulation. Single cell sequencing further revealed a fibroblast-like phenotype of Sca1⁺ SPCs-derived SMCs. Protein array sequencing and in vitro assays revealed that SMC regeneration from Sca1⁺ SPCs was regulated by Malat1 through miR125a-5p/Stat3 signaling pathway. These findings delineate the critical role of Sca1⁺ SPCs in vascular remodeling and reveal that lncRNA Malat1 is a key regulator and might serve as a novel biomarker or potential therapeutic target for vascular diseases.

Intervention with selution SLR™ Agent Balloon for Endovascular Latent Limus therapy for failing AV Fistulas (ISABELLA) Trial: Protocol for a pilot clinical study and pre-clinical results

BACKGROUND

The aim of this pilot clinical study is to evaluate the safety and efficacy of the Selution Sustained Limus Release (SLR)™ sirolimus-coated balloon (M.A. MedAlliance SA, Nyon, Switzerland) for improving the patency of failing arterio-venous fistulas (AVF) in hemodialysis patients. We also present herein a pre-clinical pharmacokinetic and safety evaluation of Selution™ to justify its first use in hemodialysis patients for endovascular access salvage.

METHODS AND RESULTS

This is an investigator-initiated prospective single-center, non-blinded single-arm trial. Forty patients with clinically significant de novo or recurrent stenoses in a mature AVF circuit will be recruited. All stenotic lesions will be prepared with high pressure non-compliant conventional balloon angioplasty (CBA) prior to deployment of the Sustained-Release Selution™ sirolimus drug-eluting balloon. The primary efficacy endpoint is 6-month target lesion primary patency and the primary safety endpoint is freedom from localized or systemic serious adverse events through 30 days. Secondary endpoints of interest include technical and clinical success rates and circuit access patency at 3 and 6 months. Follow-up will occur for 2 years for those patients whose AVFs remain patent. Pharmacokinetic and histological animal safety studies performed with the Selution™ coating formulation showed prolonged arterial tissue retention of sirolimus with therapeutic levels up to 60 days and non-toxic and rapidly declining blood levels. Histological results in animal models demonstrated safety, freedom from intraluminal thrombus, reduction in restenosis by sirolimus elution compared to CBA, and no evidence of embolic phenomena indicative of adverse particulate effects.

DISCUSSION

Long release sirolimus coated balloons may serve as a promising novel alternative therapy to paclitaxel-based technology for treating conduit stenosis secondary to neointimal hyperplasia. Pre-clinical pharmacokinetic and histological animal data are encouraging and provide suggestion of safety and efficacy in this setting. This single-center trial will provide a first step toward demonstration of efficacy and safety of this device for treatment of stenotic fistulas.

Intimal growth on the luminal surface of arteriovenous grafts in rats

BACKGROUND

Endothelial cells are known to grow on the luminal surface of arteriovenous grafts (AVGs) used in hemodialysis. Although endothelial cells are important for preventing infection, a detailed growth of endothelial cells in AVGs is unknown. This study sought to create a simpler animal model of AVGs and to investigate how endothelial cells form on the luminal surface.

METHODS

Polyethylene grafts were placed between the cervical artery and vein of Wistar rats. The grafts were removed at 6 h, 24 h, 3 days, or 7 days after placement. The luminal surface was observed under optical and polarizing microscopy and stained with endothelial cell markers (LEL, CD31), the progenitor cell marker CD34, and the macrophage marker ED-1.

RESULTS

Microscopy demonstrated many diffuse vascular endothelial cells on the luminal surface of AVGs after placement. While there was no difference in the number of LEL-positive cells between the arterial side (AS) and venous side (VS) at 6 h or 7 days, there were significantly more of these cells on the VS at both 24 h and 3 days (p < 0.05). Analysis at 24 h showed some CD31-positive cells and few CD34-positive cells.

CONCLUSIONS

This was the first study to use a simple rat model of AVG placement. Endothelial cell formation was initially more active on the VS than on the AS, but these cells subsequently increased in number across the luminal surface. Future clinical studies might contribute clinically by confirming whether AS versus VS puncture results in different infection rates.

Analysis of predictive factors of thrombosis in autogenous arteriovenous fistula

PURPOSE

To investigate the predictors of early diagnosis of thrombus of autogenous arteriovenous fistula (aAVF).

METHODS

The included patients were divided into the thrombus group with aAVF failure or thrombosis and the control group with good internal fistula function. The general data of the patients, including age, sex, diabetes mellitus, were collected. Platelets (PLT), platelet crit (P-LCR), platelet distribution width (PDW), mean platelet volume (MPV), homocysteine (HCY), and other biochemical data were collected. The predictors of thrombus of aAVF were obtained by the t test and logistic regression analysis, and receiver operating characteristic (ROC) curve analysis was used to compare the area under the ROC curve (AUC) between the combined predictors and the original indicators. The optimal critical value was determined when the Youden index reached its maximum value, and the sensitivity, specificity, accuracy, diagnostic index, and so on were calculated. Finally, prediction was performed by substituting each value in individually.

RESULTS

PLT, PDW, P-LCR, MPV, and HCY showed significant differences between two groups (p < 0.05). Logistic regression analysis showed that, for PLT (OR = 1.014, 95% CI 1.006-1.022, p = 0.01), PDW (OR = 1.295, 95% CI 1.009-1.661, p = 0.042), P-LCR (OR = 1.230, 95% CI 1.089-1.389, p = 0.001), MPV (OR = 1.696, 95% CI 1.101-2.613, p = 0.017), and HCY (OR = 1.332, 95% CI 1.182-1.502, p = 0.01), the difference was significant; PLT, PDW, P-LCR, MPV, and HCY were positively correlated with thrombogenesis (p < 0.05). By logistic regression, a group of the five predictors of PLT, PDW, P-LCR, MPV, and HCY was obtained, and the combined predictors were 0.014*PLT + 0.258*PDW + 0.207*P-LCR + 0.528*MPV + 0.287*HCY. The area under the curve of the combined predictor was 0.933, the sensitivity was 92.4%, the specificity was 81.2%, the maximum diagnostic index was 0.736, the diagnostic cutoff point was 21.790, and the accuracy rate was 87%.

CONCLUSION

PLT, PDW, P-LCR, MPV, and HCY are predictors of thrombus of aAVF. They can better predict thrombus of aAVF, and the combination of these five indicators is better than a single indicator.

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.

The role of stents in hemodialysis vascular access

Vascular access is the Achilles' heel of dialysis therapy among patient with end stage kidney disease. The development of neointimal hyperplasia and subsequent stenosis is common in vascular access and is associated with significant morbidity. Percutaneous transluminal angioplasty using balloon inflation was the standard therapy of these lesions. However, the balloon-based approaches were associated with poor vascular access patency rate necessitating new inventions. It is within this context that different types of stents were developed in order to improve the overall dialysis vascular access functionality. In this article, we review the available literature regarding the use of stents in treating dialysis vascular access stenotic lesions. Further, we review the major clinical trials of stent use in different anatomic locations and in different clinical scenarios.

Temporal regulation of notch activation improves arteriovenous fistula maturation

BACKGROUND

Arteriovenous fistula (AVF) maturation is a process involving remodeling of venous arm of the AVFs. It is a challenge to balance adaptive AVF remodeling and neointima formation. In this study we temporally controlled Notch activation to promote AVF maturation while avoiding neointima formation.

METHODS

Temporal Notch activation was controlled by regulating the expression of Notch transcription factor, RBP-Jκ, or dnMAML1 (dominant negative MAML2) in vascular smooth muscle cells (VSMCs). AVF mouse model was created and VSMC phenotype dynamic changes during AVF remodeling were determined.

RESULTS

Activated Notch was found in the nuclei of neointimal VSMCs in AVFs from uremic mice. We found that the VSMCs near the anastomosis became dedifferentiated and activated after AVF creation. These dedifferentiated VSMCs regained smooth muscle contractile markers later during AVF remodeling. However, global or VSMC-specific KO of RBP-Jκ at early stage (before or 1 week after AVF surgery) blocked VSMC differentiation and neointima formation in AVFs. These un-matured AVFs showed less intact endothelium and increased infiltration of inflammatory cells. Consequently, the VSMC fate in the neointima was completely shut down, leading to an un-arterialized AVF. In contrast, KO of RBP-Jκ at late stage (3 weeks after AVF surgery), it could not block neointima formation and vascular stenosis. Inhibition of Notch activation at week 1 or 2, could maintain VSMC contractile markers expression and facilitate AVF maturation.

CONCLUSIONS

This work uncovers the molecular and cellular events in each segment of AVF remodeling and found that neither sustained increasing nor blocking of Notch signaling improves AVF maturation. It highlights a novel strategy to improve AVF patency: temporally controlled Notch activation can achieve a balance between adaptive AVF remodeling and neointima formation to improve AVF maturation.

TRANSLATIONAL PERSPECTIVE

Adaptive vascular remodeling is required for AVF maturation. The balance of wall thickening of the vein and neointima formation in AVF determines the fate of AVF function. Sustained activation of Notch signaling in VSMCs promotes neointima formation, while deficiency of Notch signaling at early stage during AVF remodeling prevents VSMC accumulation and differentiation from forming a functional AVFs. These responses also delay EC regeneration and impair EC barrier function with increased inflammation leading to failed vascular remodeling of AVFs. Thus, a strategy to temporal regulate Notch activation will improve AVF maturation.

Novel electrospun polyurethane grafts for vascular access in rats

OBJECTIVES

The purpose of this study is to develop a new and improved polyurethane (PU) graft using electrospinning and chemical modifications for hemodialysis patients, which will replace the current standard, polytetrafluoroethylene (PTFE) graft. The chemical modifications aim to improve hemocompatibility and reduce thrombogenicity and neointimal hyperplasia.

METHOD

The study population was randomized and divided equally into four groups; one control group received a PTFE graft, and three treatment groups received three different types of polyurethane grafts. Two duplex measurements were performed directly on the graft on the same locations, followed by a histologic examination.

RESULTS

In the first few days after the implantation animals lost some weight, it took a week to recover to pre-surgical weight. Throughout the 28 days, there was no significant difference between animals in wound, activity, and the general appearance. PTFE and PU A groups have lower compliance or reduced graft diameter due to neointimal hyperplasia development on Doppler interrogation. The histological analysis showed limited neointimal hyperplasia development and no excessive inflammatory response to any of the grafts.

CONCLUSION

This study demonstrates that animals with polyurethane grafts show better blood flow because the developed NIH was inconspicuous, as indicated by the different velocity measure than controls on Duplex and minimal NIH development microscopically.

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.

The association of long-term blood pressure variability with hemodialysis access thrombosis

Background

Blood pressure variability (BPV) is an important risk factor for cardiovascular events in hemodialysis patients. We sought to determine the impact of BPV on hemodialysis access thrombosis.

Methods

We enrolled 1,011 prevalent hemodialysis patients from 12 hemodialysis centers since January 2018 and followed them until December 2020. Predialysis blood pressure (BP) was assessed at 12-week intervals. The coefficient of variation derived from 36 consecutive BP measurements was used as the metric for variability. The primary outcome was incident hemodialysis access thrombosis. Linear regression models were used to assess factors associated with BPV at baseline. Kaplan-Meier curves of the time until vascular access events were drawn and log-rank tests were calculated. Cox proportional hazards models were performed to assess the association of BPV with incident vascular access events.

Results

The average coefficient of variance for systolic BPV was 10.9%. BPV was associated with age, body mass index, mean BP, diabetes, coronary and peripheral artery disease, history of access dysfunction, graft access, intradialytic hypotension, and use of antihypertensive medications. There were 194 access thrombosis events and 451 access stenosis events during a median follow-up period of 30 months. After adjustment of potential confounding factors, BPV was associated with increased risk of access thrombosis [hazard ratio = 1.27, 95% confidence interval (CI), 1.18–1.44, per 1 standard deviation increase in BPV]. The patients in the highest BPV quartile had 2.45 times the risk of thrombosis (CI, 1.62–3.70). The association was independent of average BP, intradialytic hypotension, and comorbidities. Similar trends of association were found in the subgroups analyzed. Comparative analysis using a time-varying variable model and different metrics of BPV showed consistent results.

Conclusion

Our findings underscored the impact of BP fluctuation on vascular access thrombosis.

Functional analysis of arteriovenous fistulae in non-contrast magnetic resonance images

BACKGROUND AND OBJECTIVE

Arteriovenous fistulae (AVF) are the preferred mode of hemodialysis vascular access and their successful maturation is critical to reduce patient morbidity, mortality, cost, and improve quality of life. Peri-anastomotic venous segment stenosis is the primary cause of AVF maturation failure. The objective is to develop a software protocol for the functional analysis of arteriovenous fistula.

METHOD

We have developed a standard protocol for the anatomical analysis of the AVF to better understand the mechanisms involved in AVF stenosis and to identify future imaging biomarkers for AVF success or failure using non-contrast magnetic resonance imaging (MRI). The 3D model of the AVF is created using a polar dynamic programming technique. Analysis has been performed on six Yorkshire cross domestic swine, but techniques can be applied into clinical settings.

RESULTS

Differences in AVF angles and vein curvature are associated with significant variability of venous cross-sectional area. This suggests that the pattern of stenosis is likely to be dependent upon hemodynamic profiles which are largely determined by AVF anatomical features and could play an important role in AVF maturation.

CONCLUSIONS

This protocol enables us to visualize and study the hemodynamic profiles indirectly allowing early stratification of patients into high and low risk groups for AVF maturation failure. High risk patients could then be targeted with an enhanced process of care or future maturation enhancing therapies resulting in a much-needed precision-medicine approach to dialysis vascular access.

A randomised control trial protocol of MuST for vascular access cannulation in hemodialysis patients (MuST Study): contributions for a safe nursing intervention

BACKGROUND

The vascular access preservation and the maintenance of a complication-free fistula remains an Achilles' heel of hemodialysis in chronic kidney patients due to its substantial contribution to the morbidity and mortality. Systematic studies in the area of examining cannulation practices, achieving complication-free cannulation, and strategies to improve fistula survival are needed. For this reason, we consider it essential to create and investigate new methodologies for approaching fistula in patients on regular HD. The Multiple Single Cannulation Technique (MuST) is based on the association between the rope-ladder (RL) using the arteriovenous vessel through progressive rotation, and the buttonhole (BH) since there are three specific cannulation sites for each cannulation day during the week. The MuST is simple to implement and seems to be a very promising technique in terms of patient safety. Previous studies already showed an arteriovenous fistula survival similar to RL but significantly higher than BH.

METHODS

This MuST study is a multicenter, prospective, non-blind, parallel-group, randomized controlled trial with the intervention group submitted to MuST and a control group undergoing the rope-ladder, up to 100 subjects for each group. Patients will be randomized 1:1 to one of two cannulation technique (CT), and the follow-up period of this study will be 12 months. Primary outcome is to evaluate the arteriovenous fistula survival rate at 12 months determined by the percentage of fistulas in use from the beginning of the study to the date of the first clinical intervention by angioplasty or vascular surgery, to maintain or restore patency (unassisted patency). Secondary outcome is to evaluate arteriovenous fistula survival rate at 12 month determined by the percentage of fistulas in use from the study start to the date of access abandonment due to dysfunction, patient abandonment, or death, treatment change modality or study end. We will also evaluate the assisted primary patency and include the following secondary outcomes associated with the cannulation technique: Infection, Hematoma, Aneurysm development, and pain.

DISCUSSION

The study will investigate whether fistula survival can be improved when using cannulation by MuST compared to the RL. MuST study will provide important information on fistula survival when cannulated by MuST but also information related to its use in fistulas previously cannulated by other CTs.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT05081648 registered on 18 October 2021.

An analysis of vascular access thrombosis events from the Proactive IV Iron Therapy in Hemodialysis Patients (PIVOTAL) trial

Introduction

Treatment of anemia in dialysis patients has been associated with increased risk of vascular access thrombosis (VAT). Proactive IV irOn Therapy in hemodiALysis Patients (PIVOTAL) was a clinical trial of proactive compared with reactive i.v. iron therapy in patients requiring hemodialysis. We analyzed the trial data to determine whether randomized treatment arm, alongside other clinical and laboratory variables, independently associated with VAT.

Methods

In PIVOTAL, 2141 adult patients were randomized. The type of vascular access (arteriovenous fistula [AVF], arteriovenous graft [AVG], or central venous catheter [CVC]) was recorded at baseline and every month after randomization. The associations between clinical and laboratory data and first VAT were evaluated in a multivariate analysis.

Results

A total of 480 (22.4%) participants experienced VAT in a median of 2.1 years of follow-up. In multivariable analyses, treatment arm (proactive vs. reactive) was not an independent predictor of VAT (hazard ratio [HR] 1.13, P = 0.18). Diabetic kidney disease (HR 1.45, P < 0.001), AVG use (HR 2.29, P < 0.001), digoxin use (HR 2.48, P < 0.001), diuretic use (HR 1.25, P = 0.02), female sex (HR 1.33, P = 0.002), and previous/current smoker (HR 1.47, P = 0.004) were independently associated with a higher risk of VAT. Angiotensin receptor blocker (ARB) use (HR 0.66, P = 0.01) was independently associated with a lower risk of VAT.

Conclusion

In PIVOTAL, VAT occurred in nearly 1 quarter of participants in a median of just >2 years. In this post hoc analysis, randomization to proactive i.v. iron treatment arms did not increase the risk of VAT.

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.

Mean Platelet Volume: A Possible Predictor for Patients with Decompensated Chronic Heart Failure

Purpose

Despite all medical efforts and discoveries, heart failure (HF) remains one of the most important and common public health problems, with high mortality and hospitalization rates, due to decompensation of HF. In the present study, we aimed to identify a predictive factor through which we can evaluate the risk of readmission and mortality in the first year, given the initial admission of a patient with decompensated heart failure.

Patients and Methods

The parameter we have investigated is the mean platelet volume (MPV). Studies have shown that there is a significant correlation between the value of MPV and the risk of cardiovascular disease (CVD) and cardiovascular (CV) death. In this study, we enrolled 130 patients hospitalized for decompensated chronic HF (NYHA class IV HF or acute pulmonary edema) and analyzed whether there is a relationship between the value of the MPV at admission and 6-month rehospitalization, and 1-year mortality, respectively.

Results

The statistical analysis revealed significantly different values (p = 0.041) for MPV at admission between the group of patients without decompensated chronic HF compared to the group of patients with decompensated chronic HF (8.74 fl vs 9.08 fl). Also, the results of our study revealed that patients with decompensated chronic heart failure who were readmitted at 6 months and died at 1 year, respectively, had a higher MPV at admission (>9 fl), compared to those without the above-mentioned events, with a statistical significance.

Conclusion

A higher MPV at admission can be considered in our study as an independent predictor for rehospitalization and 1-year mortality of patients with decompensated chronic HF.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Preoperative Cardiac Index as a Predictor of Maturation and Primary Patency of Radiocephalic Arteriovenous Fistula in Hemodialysis

BACKGROUND

Radiocephalic arteriovenous fistula (RCAVF) is the best access modality to be considered initially when planning arteriovenous fistula (AVF) for maintenance hemodialysis. Considering the higher incidence of RCAVF failed maturation (M), it is important to perform proper preoperative evaluation and identification of high-risk patients. There has been no study on the influence of preoperative cardiac function on the M and patency of AVFs. The purpose of this investigation is to determine whether preoperative cardiac index (CI) is a predictor of M and primary patency of RCAVF.

METHOD

A total of 365 end-stage renal disease patients undergoing RCAVF surgery were consecutively enrolled with a median follow-up time of 20 months in this prospective cohort study. Demographics, vascular diameters measured by duplex ultrasound examination, and CI measured by echocardiography, were analyzed for effect on RCAVF primary functional M and primary patency.

RESULT

Patients in the group achieving primary RCAVF functional M had a significantly larger mean CI than the group with early RCAVF failure (2.93 ± 0.77 vs. 3.57 ± 0.76 L/min/m2, p < 0.001). The receiver operating characteristic curve was plotted and demonstrated that preoperative vein diameter and CI can predict failure of RCAVF M. The AUC of CI was higher (0.745 vs. 0.666). Multivariate regression analysis, adjusted for age, sex, diabetes, preoperative dialysis status and vessel diameters, showed that decreased CI remained associated with increased risk of failure of M (FM) and worse primary unassisted patency. The Kaplan-Meier survival analysis suggested that patients with CI <3 L/min/m2 had a worse primary unassisted patency rate at all time points compared with patients with CI ≥3 L/min/m2.

CONCLUSION

This study demonstrated that preoperative CI was associated with RCAVF M and long-term patency. A decreased CI may be a possible predictor of an increased risk of FM and a shorter primary patency time.

Pentraxin 3 Predicts Arteriovenous Fistula Functional Patency Loss and Mortality in Chronic Hemodialysis Patients

INTRODUCTION

Viable vascular access is the lifeline for hemodialysis patients. In the nondialysis population, emerging evidence suggests that circulating pentraxin 3 (PTX3), neutrophil gelatinase-associated lipocalin (NGAL), and chitinase-3-like protein 1 (CHI3L1) are associated with cardiovascular inflammation and endothelial injury. However, predictive values of these three biomarkers on arteriovenous fistula (AVF) outcomes are unknown.

METHODS

This prospective observational cohort study enrolled 135 hemodialysis patients using AVF and then followed them for 3 years. Plasma levels of PTX3, NGAL, and CHI3L1 were measured. Patients were followed up prospectively for two clinical outcomes, including AVF functional patency loss and death. Cox proportional hazards regression models were used to analyze hazard ratios for the commencement of AVF functional patency loss and mortality.

RESULTS

Among 135 patients, the mean age was 66.0 ± 15.7 years old and 48.1% were male. The plasma level of PTX3, NGAL, and CHI3L1 was 2.8 ± 2.3 ng/mL, 349.2 ± 111.4 ng/mL, and 185.5 ± 66.8 ng/mL, respectively. During a 3-year follow-up period, the plasma level of PTX3 was an independent predictor for AVF functional patency loss (per 1 ng/mL increase, HR 1.112 [95% CI: 1.001-1.235], p = 0.048). Besides, patients with higher plasma levels of PTX3 were more likely to suffer from cardiovascular mortality (per 1 ng/mL increase, HR 1.320 [95% CI: 1.023-1.703], p = 0.033), infectious mortality (per 1 ng/mL increase, HR 1.394 [95% CI: 1.099-1.769], p = 0.006), and all-cause mortality (per 1 ng/mL increase, HR 1.233 [95% CI: 1.031-1.476], p = 0.022).

CONCLUSIONS

The plasma level of PTX3, not NGAL or CHI3L1, was associated with higher risks of AVF functional patency loss in chronic hemodialysis patients, showing its value in reflecting AVF endothelial dysfunction. Furthermore, PTX3 also predicts mortality in chronic hemodialysis patients.

Drug-Coated Balloons for the Dysfunctional Vascular Access: An Evidence-Based Road Map to Treatment and the Existing Obstacles

An underlying stenosis within the venous limb of a hemodialysis access circuit is the main etiology for graft and fistula dysfunction as well as other symptoms such as arm, breast, and neck swelling. Treatment options for both peripheral and central venous stenoses include plain old balloon angioplasty, angioplasty with drug-coated balloons, and stenting. This article discusses the current evidence for the use of drug-coated balloon angioplasty in this patient population.

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.

Procedure and Clinical Success of Drug-Coated Balloon Fistuloplasty of the Drainage Vein in Dysfunctional Native Arteriovenous Fistulas

Purpose

Native arteriovenous fistulas (AVFs) are the most effective vascular access (VA) for haemodialysis. We aimed to evaluate the results of balloon angioplasty (fistuloplasty) from drainage vein performed for the treatment of AVF dysfunction in haemodialysis patients and examine potential patient and AVF-associated factors that might affect such results.

Methods

This is a nonrandomized, retrospective, and single-centred study. A total of 105 balloon fistuloplasties were performed for dysfunctional AVFs of 82 haemodialysis patients. Patients were treated with a drug-coated balloon according to standard procedures. Evaluations were performed by physical examinations and if needed by color Doppler imaging in every 6 months. The primary endpoint was patency by balloon fistuloplasty. Patency was evaluated clinically by detecting the thrill in AVF and by the adequacy of the dialysis. Multidimensional scaling (MDS) technique was used as a method for the statistical analysis.

Results

The success of the procedure after the first attempt was 85.3% with 70 patients. Patency in the 6th, 12th, 18th, and 24th months were 63 (76.8%), 60 (73.1%), 53 (64.6%), and 44 (54%), respectively. The procedure was considered successful when the thrill was detected in AVF and when dialysis was adequate. The statistical analysis by MDS revealed that patients' age was the most effective factor acting on the procedure success followed by the age of AVF. Other patient-associated and AVF-associated factors were not found as effective statistical evaluation.

Conclusions

Haemodialysis through native AVFs with restored functionality contributes positively to the life span and the quality of life of the patient. Probably, advanced age and high fistula age are unfavourable factors leading to the development of neointimal hyperplasia and venous stenosis. Balloon fistuloplasty of the draining vein is an effective and safe method regardless of patient age and the age of AVF.