Arteriovenous Fistula Creation Research Articles

PREDICTING HIGH FLOW ARTERIOVENOUS FISTULAS AND CARDIAC OUTCOMES IN HEMODIALYSIS PATIENTS.

Heart failure is common in patients receiving hemodialysis. A high flow arteriovenous fistula (AVF) may represent a modifiable risk factor for heart failure and death. Currently, no tools exist to assess the risk of developing a high flow AVF (>2000 mL/min). The aim of this study was to use machine learning to develop a predictive model identifying patients at risk of developing a high flow AVF and to examine the relationship between blood flow, heart failure, and death. Between 2011 and 2020, serial AVF blood flows were measured in 366 prevalent hemodialysis patients at two tertiary hospitals in Australia. Four prediction models (deep neural network, and 3 separate tree-based algorithms) employing age, first AVF flow, diabetes, and dyslipidemia were compared to predict high flow AVF development. Logistic regression was used to assess the relationship between AVF blood flow, heart failure, and death. High flow AVFs were present in 31.4% of patients. The bootstrap forest predictive model performed best in identifying those at risk of a high flow AVF (AUC 0.94, sensitivity 86%, specificity 83%). Heart failure prior to vascular access creation was identified in 10.2% of patients with an additional 24.9% of patients developing heart failure after AVF creation. Long-term mortality after access formation was 27%, with an average time to death after AVF creation of 307.5 ± 185.6 weeks. No univariable relationship using logistic regression was noted between AVF flow and incident heart failure after AVF creation or death. Age, flow at first measurement >1000 mL/min, time to highest AVF flow, and heart failure predicted death after AVF creation using a general linear model. Predictive modelling techniques can identify patients at risk of developing high flow AVF. No association was seen between AVF blood flow rate and incident heart failure after AVF creation. In those patients who died, time to highest AVF flow was the most important predictor of death after AVF creation.

Single or dual antiplatelet therapy improves one-year arteriovenous graft patency and overall survival

IntroductionFollowing new dialysis access creation there is no consensus on the optimal use of anti-thrombotic therapy. Recent studies have suggested that single antiplatelet therapy may improve hospital mortality as well as patency. The aim of this study was to assess the role of different antiplatelet and anticoagulation therapies on outcomes following dialysis access creation. Material and MethodsA retrospective study was conducted utilizing patients from the Vascular Quality Initiative who underwent AV fistula (AVF) and AV graft (AVG) creation from 2011-2023. Patients who were antiplatelet and anticoagulation naive were separated into four cohorts: no antiplatelet (No APT), single antiplatelet (SAPT), dual antiplatelet (DAPT), and aspirin with anticoagulation (ASA + AC). Univariate Kaplan-Meier (KM) and multivariable regression analyses were conducted to assess overall survival, primary patency, and secondary patency. Results49,980 patients with AVF creation and 12,688 patients with AVG creation were identified. AVG patients had improved 1-year primary patency with SAPT compared to No APT (48% vs 44%, p = 0.03) on KM analysis. No difference on KM analysis was observed for AVF. Regression analysis showed decreased risk of loss of primary patency for AVF (HR 0.90, CI 0.83-0.97, p = 0.009). AVG with SAPT showed decreased risk of mortality (HR 0.80, CI 0.64 – 1.00, p = 0.05) and decreased risk of loss of primary patency (HR 0.80, CI 0.67-0.94, p = 0.009). DAPT also showed decreased risk of loss of primary patency for AVG (HR 0.64, CI 0.43-0.95, p = 0.028). Survival was worse for both AVF and AVG patients on ASA + AC on KM analysis. ConclusionsSingle antiplatelet therapy following access creation improves primary patency for both AVF and AVG, as well as overall survival for those with AVG. DAPT may further improve primary patency in those with AVG. The use of anticoagulation shows no clear benefit and may be harmful, however is more likely to reflect higher risk patients with other co-morbidities. These results suggest that following an AVF one should consider discharging patients on SAPT, and following an AVG one should consider SAPT or DAPT.

The Impact of Surgical Timing on Outcomes in Patients Undergoing Arteriovenous FistulaCreation for Hemodialysis. A Meta-analysis

Background: Arteriovenous fistula (AVF) creation is the preferred method for vascular access in hemodialysis patients, offering better long-term patency, fewer complications, and lower infection rates compared to other options. However, the timing of AVF creation plays a critical role in determining outcomes. This meta-analysis examines the impact of surgical timing on AVF success, focusing on primary failure rates, maturation time, patency, and postoperative complications. Objectives: We sought to evaluate whether the timing of AVF creation impacts outcomes in hemodialysis patients and to provide evidence-based recommendations for clinical practice. Methods: Following PRISMA guidelines, a comprehensive meta-analysis was conducted from major databases (PubMed, Embase, Cochrane) until 2024 that included data. We selected studies based on defined criteria, and assessed for quality using the Newcastle-Ottawa Scale and Cochrane Risk of Bias tool. Primary failure rates, maturation time, primary and secondary patency and postoperative complications were analyzed as outcomes. Heterogeneity was addressed with random effects models, and subgroup analyses were carried out on the basis of patient characteristics. Results: Early AVF creation (creating an AVF ≥ 6 months prior to dialysis initiation) was shown to reduced primary failure rate by 50%, shortened maturation time by 2 to 3 weeks and increase primary patency rates by up to 35%. Early AVF creation, on the other hand, was also accompanied by fewer postoperative complications, including infection and thrombosis, versus delayed AVF creation. Consistent benefits were seen for different patient profiles in subgroup analyses. Conclusion: Early AVF creation is associated with superior outcomes, including lower failure rates, quicker maturation, and fewer complications. These findings support early AVF as the preferred practice in hemodialysis care, enhancing long-term patient outcomes and quality of care.

Abstract 4124084: Nitric Oxide Releasing Bionanomatrix Gel For Dialysis Arteriovenous Fistula Maturation

Introduction: About 600,000 patients in the US suffer from end-stage renal disease (ESRD); more than 75% of ESRD patients undergo dialysis. Vascular access dysfunction is a major cause of morbidity and hospitalization in dialysis patients. Arteriovenous fistulas (AVFs) are considered the gold standard of vascular access for dialysis. However, about 60% of AVFs fail to mature because of early venous neointimal development and poor vasodilation and vascular wall remodeling. Therefore, to promote AVF maturation, we propose the application of a nitric oxide (NO) releasing nanomatrix gel, or ‘NO gel’, on the created AVF. The NO gel is composed of peptide amphiphiles (PA), which contain a polylysine (KKKKK) group to form NO-donating residues. In this study, we test our hypothesis that the NO gel applied at AVF can promote AVF maturation by decreasing venous intimal hyperplasia, enhancing vasodilation and vascular outward remodeling in porcine model. Materials and Methods: PA containing with KKKKK was synthesized and charged with NO to produce NO gel. For in vivo studies, AVFs in porcine were created by connecting the jugular vein and carotid artery. The NO gel was applied perivascularly over the AVF anastomosis. And the pigs were sacrifice after 35 days. AVF hemodynamics were evaluated using MRI-based computed fluid dynamics analysis. Results: We found significant decrease in neointimal hyperplasia in porcine AVFs treated with NO gel compared to the control groups. Additionally, the percentage of open lumens was significantly higher in the NO gel-treated group. It is indicated that veins in NO treated group showed less fibrosis as an less type I collagen I produced in the NO treated group than control. Also, the NO gel significantly improved hemodynamics and vascular remodeling of porcine AVFs compared to the control. Conclusion: These results suggest that the NO gel plays a crucial role in AVF maturation by reducing intimal hyperplasia and stenosis following AVF creation in a pig model. When intimal hyperplasia is reduced and the vessel is dilated, less tensile force of blood flow is applied on the arterialized vein, directing the AVF to appropriate maturation.

Abstract 4137902: Layer-specific Gene Expression Associated with Intima Hyperplasia in Arterio-venous Fistula

Background: The mechanism of hemodialysis arteriovenous fistula (AVF) vein intima hyperplasia (IH) may be specific to its layers (intima, media, and adventitia) but is poorly understood. To address this gap, we studied layer-specific transcriptomics related to IH in veins of two-stage AVF creation. Methods: Vein samples were collected during the initial creation of brachial artery-basilic vein AVF (1st stage) and vein transposition surgery 6 weeks later (2nd stage) and were sectioned in OCT. Tissues from each layer were separately collected by laser microdissection. Following Takara’s SMARTer Stranded Total RNA-Seq Pico Input protocol, libraries were constructed and sequenced in NovaSeq. The sequencing reads were processed by fastp, aligned to genome GENCODE 45 by STAR and gene-level counts were estimated by RSEM. Intima was assessed by histology. Layer-specific differentially expressed genes in pre-access or AVF veins associated with IH in AVF veins were detected by edgeR and further identified the enriched pathways and predicted functions using Qiagen IPA. Results: 44 veins were collected from 22 patients. 13,522 protein-coding genes that had a raw count of at least 10 in more than 70% of samples were included in analysis. 10 AVF veins had severe IH. Among the layers of pre-access vein, intima had the largest number of genes significantly associated with severe AVF IH and most or all these genes were upregulated (35/4, 26/2, 5/0 for the number of up/downregulated genes in intima, media, and adventitia of pre-access vein, respectively); cellular movement and immune cell trafficking were more strongly activated in intima of pre-access vein with severe AVF IH. No genes in any layer of AVF vein were significantly associated with severe AVF IH. From 1 st to 2 nd stage, more genes significantly changed expression in intima with severe AVF IH than intima without severe AVF IH (197/150 vs 144/93 for up/downregulated genes), while media (20/4 vs 149/31) and adventitia (99/27 vs 196/70) were the opposite; TGFB1, angiotensinogen, and TNF were more strongly activated in intima, while cell survival and migration were diminished in media and adventitia with severe AVF IH, respectively. Conclusion: Intima of pre-access vein has more genes associated with severe AVF IH. The layer-specific gene expression changes during AVF development and predicted functions are associated with AVF IH. These data can be used to develop layer-specific therapies to reduce AVF IH.

Abstract 4118070: High Output Heart Failure After Leadless Pacemaker Placement In a Heart Transplant Recipient

Introduction: The advent of leadless pacemaker (LP) technology has revolutionized cardiac rhythm management by minimizing risks associated with traditional transvenous pacemakers. LP use is expected to increase as dual-chamber LP systems emerge into clinical practice. The LP requires a large-bore venous sheath (27-Fr) through a femoral vein. One risk of large bore femoral cannulation is creation of an occult arteriovenous fistula (AVF), which can cause high output heart failure (HOHF) over time. In the LEADLESS II trial, the event rate for AVF was 0.2%. HOHF as a complication of LP implant has not been previously reported. We describe the first case of HOHF in a heart transplant (HT) recipient after LP. Case Presentation: An 82-year-old male with a history of HT 26 years earlier underwent leadless pacemaker for recurrent syncope, deemed associated with conduction system disease. He had no history of cardiac allograft rejection, angiographic coronary allograft vasculopathy or left ventricular dysfunction. Six months post-implant he presented with shortness of breath and bilateral lower extremity edema. Management: Evaluation included: 1) Chest X-ray which was suggestive of pulmonary edema 2) natriuretic peptide level of 5,500 pg/ml (6-fold increase from 6 months prior) 3) echocardiogram showing EF of 69%, and 4) bilateral lower extremity Doppler ultrasound where he was found to have a large AVF between the right superficial femoral artery and superficial femoral vein. Subsequent right heart catheterization was notable for a PCWP of 18 mmHg and a cardiac output/index of 11 L/min and 5.8 L/min/m2 respectively, hence confirming HOHF. Treatment with intravenous diuretic was initiated and percutaneous stent placement to correct the AVF was performed with symptomatic relief. Conclusion: This case highlights the rare but serious complication of unrecognized AVF following leadless pacemaker implant. Given that this event occurred in a HT recipient, a more exhaustive work-up was required to rule-out expected causes of congestion. To our knowledge there is only one other case report describing AVF post-LP implant for which no intervention was performed due to absence of symptoms at 6-month follow up and HOHF was not reported. Our case emphasizes that the differential diagnosis of new onset of signs and symptoms of heart failure that develop post LP implant in general and in HT recipients specifically, should include HOHF related to an unrecognized procedural AVF.

Prevalence and Center Variability of Catheter-Based Hemodialysis in Vienna: Insights from the Vienna ACTS NOW Study.

Objectives: The choice of vascular access continues to be a critical component in the management of hemodialysis patients. Despite the international consensus favoring arteriovenous (AV) fistulas, the use of central venous catheters (CVCs) remains prevalent, with substantial variations across countries and even among dialysis centers within the same region. This study examines the prevalence of CVC use among chronic hemodialysis (CHD) patients in Vienna, Austria, and explores inter-center differences. Methods: A cross-sectional analysis was conducted on patients receiving CVC-based CHD in Vienna as of March 2023. Patient demographics, comorbidities and their hemodialysis history were collected. Additionally, a subset of the population underwent vascular access (VA) mapping to assess eligibility for AV fistula (AVF) or AV graft (AVG) creation. Results: A total of 335 patients received CVC-based hemodialysis, equaling a CVC proportion of 42.5%. 191 (57.0%) patients on CVC-based CHD gave their consent to record their clinical data and vascular access history. Of the 191 included patients, 61 gave their consent to receive VA mapping. Of the 61 patients who received VA mapping, 60 (98.4%) were eligible for an upper extremity AVF or AVG. There was no significant difference regarding patient demographics, dialysis vintage, history of previous AVF or AVG or Charlson Comorbidity Index between the mapping and non-mapping group. The odds ratio of having a CVC in the absence of in-house vascular surgery was 3.41 (95% CI: 2.31-5.02, p-value < 0.001) compared to patients with in-house vascular surgery. Conclusions: The majority of patients that consented to ultrasound VA mapping fulfilled vascular requirements for AVF or AVG creation. Our study highlights the potential to decrease the prevalence of CVC-based CHD in Vienna that could translate to a reduction in CVC-associated complications.

Early and Midterm Outcomes of Percutaneous Arteriovenous Fistula Creation

Early and Midterm Outcomes of Percutaneous Arteriovenous Fistula Creation

Radial Artery Mediacalcosis in Patient with End-Stage Kidney Disease: An Incidental Intraoperative Discovered During a Radiocephalic Native Arteriovenous Fistula (AVF) Creation

Radial Artery Mediacalcosis in Patient with End-Stage Kidney Disease: An Incidental Intraoperative Discovered During a Radiocephalic Native Arteriovenous Fistula (AVF) Creation

Study protocol for a French multicenter randomized controlled trial evaluating the medicoeconomic impact of Surgical vs Endovascular Arteriovenous Access Creation for Hemodialysis in End-stage Renal Disease (ENDO-FAV)

BackgroundVascular access is indispensable for performing hemodialysis in patients with end-stage renal disease. The Kidney Disease Outcome Quality Initiative and the French Health Authority advocate for native arteriovenous fistulas (AVFs) as a primary option owing to their association with lower morbidity, mortality, and enhanced quality of life. However, a significant proportion of AVFs fail to mature, and many require multiple re-interventions, increasing overall costs. To address these issues, endovascular techniques for AVF creation have been developed. These methods use energy-based technologies, avoiding vessel dissection and preserving perivascular tissues. Initial results are promising, but these devices are expensive, and the technical act of creating an endovenous fistula is not recorded in the coding of the common classification of medical procedures and, as such, cannot be reimbursed by health insurance in France. Although international studies suggest their effectiveness, no French studies have yet replicated or confirmed these findings in the local context, which would help to support a reimbursement request from health insurance. MethodsThis protocol represents the first French medicoeconomic study to compare the two available endovascular AVF creation devices (Ellipsys and WaveLinQ) with traditional open surgery. This multicenter, comparative clinical trial will randomize patients into two parallel groups: (1) endovascular AVF creation using either the WaveLinQ or Ellipsys device, and (2) surgical proximal AVF creation (brachiocephalic/brachiobasilic). Randomization will be balanced and stratified by center and dialysis timing. Follow-up assessments will occur at 1 week and 1, 3, 6, 12, and 18 months. The primary objective is to evaluate the cost effectiveness of endovascular AVF creation compared with open surgery from the perspective of the French health care system. The primary end point is the cost-utility ratio (cost per quality-adjusted life year gained) of endovascular AVF vs open surgery. Utility is assessed using the EQ-5D-5 L questionnaire, with costs derived from micro-costing and the National Health Data System. Secondary outcomes include health economics with total costs at 18 and 36 months, success rate of vascular access creation, AVF maturation and functionality, recirculation rates, early and late access failures, cannulation success, primary and secondary patency, reintervention rates, and adverse events. Based on a cost-utility threshold of €30,000 per quality-adjusted life year, cost difference estimates, and standard deviations from previous studies, anticipated sample size is 126 patients per group (endovascular and surgical), totaling 252 patients with approximately 142 patients for the Ellipsys device and 110 patients for WaveLinQ, based on the capacity of 7 centers using Ellipsys and 4 centers using WaveLinQ. ConclusionsThis multicenter randomized controlled trial will provide contemporary data on the clinical outcomes and prognoses for endovascular AVF techniques, potentially establishing endovascular methods as a viable and cost-effective alternative to traditional surgical AVF creation.

Safety and efficacy of an innovative external support device for de novo arterio-venous fistula creation: a French bicentric experience.

The aim of this study was to evaluate the safety and efficacy of VasQTM, a permanent extravascular nitinol vascular support device, implanted around the anastomosis of de novo arteriovenous fistulas (AVF), in consecutive patients. This was a French prospective bicentric study. All patients with an indication for creation of a distal or proximal end to side AVF performed by supervised trainee were eligible. Follow-up was performed clinically and by Duplex scan at 6 weeks and 6 months post fistula creation. Primary endpoint was functional maturation at 6 weeks defined as successful use for dialysis via 2-needle cannulation in dialysis patients or a flow rate of ≥600 mL/min and a target vein diameter ≥6 mm for pre-dialysis patients. Overall functional success for dialysis patients was assessed as well. Between March and November 2022, 21 patients received the VasQTM device and were followed for an average of 165 days. Median age was 61. Eleven patients (52%) were on dialysis at the time of implantation. AVFs were created with distal radial (N.=8), proximal radial (N.=5), brachial cephalic (N.=4) or brachial basilic (N.=4) arteries with 100% technical success . Functional maturation at 6-weeks was achieved in 81% (17/21). Functional success was 80% (12/15) with unassisted functional success of 67% (10/15) at 6 months for patients requiring dialysis at that time point. Two reoperations were performed within the device, one thrombectomy and one angioplasty, both were successful. Freedom from access-related interventions occurred in 71% (15/21) of the study population at 6-months. This study demonstrates that the VasQTM AVFs achieved high rates of maturation at 6-weeks, without the need to modify standards of care. VasQTM can successfully assist in achieving excellent results at the introduction of the device to a new center.

The relationship between post-anastomosis brachial artery flow rate and brachiocephalic arteriovenous fistula access maturity in end-stage kidney disease patients with diabetes mellitus.

From previous studies, evaluation of post-anastomosis draining-vein volume flow rate with Doppler ultrasound can be a predictor for arteriovenous fistula maturation. Due to the high variation in measurements by the effect of probe pressure in draining vein, measuring volume flow rate based on post-anastomosis feeding-artery may be an early alternative predictor of arteriovenous fistula maturation. This study aims to investigate the correlation of post-creation brachial artery volume flow rate on maturity of brachiocephalic arteriovenous fistula access in patients with end-stage kidney disease with diabetes mellitus. A retrospective cohort study was conducted on end-stage kidney disease patients with diabetes mellitus who underwent brachiocephalic arteriovenous fistula creation at three hospitals from July 2019 to March 2020. Doppler ultrasound examination of the brachial artery and draining vein volume flow rate was conducted at pre-operative, post-creation, 2 weeks, and 6 weeks post-creation. Maturity was evaluated at 6 weeks post-anastomosis. A total of 71 subjects met the inclusion and exclusion criteria, with 44 (62%) achieving maturation within 6 weeks. There was a correlation between post-anastomosis brachial artery (p < 0.001) and draining vein volume flow rate (p < 0.001) with arteriovenous fistula maturity after 6 weeks post-operatively. Brachial artery volume flow rate of ⩾350 mL/min can predict AVF maturity with a sensitivity of 95.45% (95% confidence interval = 84.86-98.74) and a specificity of 85.19% (95% confidence interval = 67.52-94.08). Post-anastomosis brachial artery flow volume can be a valuable parameter to predict brachiocephalic arteriovenous fistula maturity. It is a potential alternative to draining vein volume flow, which is technically a difficult examination.

Outcomes of arteriovenous fistula and role of duplex ultrasound for its assessment in pre-dialysis patients; a single center longitudinal study

Introduction: Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis; however, it has a primary failure rate of 20%–60%. Analyzing the factors associated with AVF failure is crucial for planning appropriate management strategies. Objectives: We aimed to identify the AVF outcomes and associated factors along with the role of duplex ultrasound (DUS) in preoperative and postoperative AVF assessment at a tertiary care hospital. Patients and Methods: This prospective observational study was conducted on pre-dialysis patients who underwent AVF creation between January 2020 and December 2021.AVF outcomes and associated clinical and vascular factors were analyzed using pre- and post-operative DUS. Results: Of 171 patients, males were predominant (83.6%), and diabetic nephropathy (42.7%) was the predominant cause of chronic kidney disease (CKD). AVF outcomes showed, 109 (63.7%) had unassisted mature AVF and 29 (16.9%) had AVF failure wherein early dialysis suitability failure was predominant (17; 9.94%). Among clinical factors, only a history of smoking correlated with AVF failure (P=0.04). On pre-and post-operative DUS assessment, the absence of distensibility and immediate post-operative vein diameter strongly correlated with AVF failure (P&lt;0.001). A unit increase (1 mm) in outflow vein diameter immediately after surgery emerged as an independent predictor of AVF outcome in both univariate (OR 0.98, 95% CI: 0.35-3.99; P&lt;0.001) and multivariate analysis (OR: 0.313, 95% CI: 0.148-0.663; P&lt;0.001). Conclusion: Most patients in our setting had unassisted AVF fistula. We additionally found that smoking correlated with AVF failure. Predominant factors determining AVF success were cephalic vein diameter, distensibility, and increase in draining vein diameter and flow volume at six weeks. This study highlights using DUS in pre- and post-operative periods, along with conventional examination to improve AVF outcomes.

Outcomes Following Arteriovenous Fistula Creation in Medicare Beneficiaries With End-Stage Kidney Disease

The objective of this study was to measure the contemporary patency rates and frequency of interventions required for arteriovenous fistula (AVF) care among a representative United States (US) population of end stage kidney disease (ESKD) patients, including by age, race and sex. All Medicare beneficiaries >20 years of age who underwent AVF graft creation for ESKD between 2017 through 2019 were included for analysis. The primary endpoints included primary patency, primary assisted patency, post-intervention patency, and fistula functionality up to one year after AVF placement. Secondary endpoint included admission for an associated adverse event following AVF creation. Multivariate analysis of patency rates was also assessed. Of 43,457 patients included in the analysis, the cumulative primary patency at 90 days was 68.4% and at one year was 31.5%. At one year, the primary assisted patency rate, post-intervention patency, and fistula use were 70.4%, 30.2% and 59.1%, respectively. There was no difference in primary patency rates when comparing age groups (age 40 – 59: HR 1.01 [95% CI 0.95 – 1.06], p = 0.84) or age ≥60: HR 0.99 [95% CI 0.93 – 1.04], p = 0.61) to the reference of age group 20 – 39. Women vs men (HR 1.16 [95% CI 1.14 – 1.20], p < 0.001) and Black vs White patients (HR 1.34 [95% CI 1.31 – 1.38], p < 0.001) and were at higher risk of experiencing primary patency failure. The cumulative incidence of admissions for adverse events was 32.6% at 1-year. In conclusion, our findings suggest that the real-world AVF patency rates remain low, with disproportionately low rates among women and Black patients.

The Occurrence of Senescence in the Arteriovenous Fistula in the Rat.

Maturational failure of dialysis arteriovenous fistulas (AVFs) not uncommonly occurs and is of considerable and timely importance. Our prior studies demonstrate that senescence, a phenotypic process that promotes vascular and other diseases, occurs in the murine AVF. In the present study, we examined whether senescence also occurs in the rat AVF model and the effect of compounds that inhibit or accelerate senescence. The rat AVF was created in the femoral vessels by an end vein-side artery anastomosis. We assessed in the AVF the expression of critical drivers of senescence, specifically, the cell cycle inhibitors p16Ink4a and p21Cip1, and such indices of a senescence phenotype as senescence-associated β-galactosidase (SA-β-gal) activity, SA-β-gal staining, and a senescence-associated secretory phenotype (SASP). We examined the effects of compounds that retard or accelerate senescence on AVF blood flow. The AVF evinced upregulation of p16Ink4a and p21Cip1 when assessed 3 days after AVF creation. The AVF also demonstrated increased SA-β-gal activity in the artery and vein; staining for SA-β-gal in the AVF artery, anastomosis, and vein; and a prominent SASP. Fisetin, an established senolytic that is protective in other models of vascular injury, when administered for 3 weeks, increased AVF blood flow and outward remodeling. Hemin, when administered for 3 weeks, decreased AVF blood flow. We demonstrate that hemin is a novel inducer of a senescence phenotype in endothelial cells, as reflected by several senescence indices. However, when administered relatively acutely (for 5 days) hemin increased AVF blood flow via HO-dependent mechanisms, as the latter was entirely prevented by a competitive inhibitor of HO activity. The rat AVF exhibits senescence within 3 days of its creation. Chronic administration of a senolytic compound (fisetin) increases AVF blood flow, whereas chronic administration of a pro-senescence compound (hemin) decreases AVF blood flow.

Efficacy of Using a Vessel Dilator during Surgery to Evaluate Vein Diameter and Predict Radiocephalic Arteriovenous Fistula Maturation and Patency

Background: We use vessel dilators to assess the diameter of the target vein during surgery for arteriovenous fistula (AVF) creation in hemodialysis patients. This study investigates the efficacy of using vein diameter as measured using dilators (surgical diameter; SD) versus that as measured by preoperative ultrasonography (ultrasonographic diameter; UD) to predict postoperative complications and patency. Methods: Sixty-three patients who underwent radiocephalic AVF creation and had measurements of UD and SD were retrospectively analyzed. Cutoff values for UD and SD regarding complications were used to dichotomize the patients into high and low groups for comparisons. Results: The 2-year primary and secondary patency rates overall were 66.5% and 88.9%, respectively. The optimal UD and SD cutoff values were 2.4 and 3.5 mm, respectively. The 2-year primary patency rate was higher in the high-SD group than the low-SD group (88.2% vs. 58.6%; p = 0.0426). The 2-year secondary patency rate was significantly higher in the high-UD/high-SD group than the low-UD/low-SD group (91.7% vs. 68.4%; p = 0.0067). Conclusions: Intraoperative measurement of vein diameter using dilators during AVF creation might be a useful method of predicting patency, particularly when SD is used in combination with UD.

Effect of a novel cannulation device for vascular access on AVF maturation in a goat carotid-jugular fistula model.

The Ark is a 3-D printed titanium device designed to be implanted around the draining vein of an arteriovenous fistula (AVF) to facilitate vascular access. The purpose of this study was to assess AVF maturation after Ark implantation in a large animal model. End-to-side AVFs were created between the carotid artery and jugular vein in nine pygmy goats that included three control (AVF only) and six experimental (AVF and Ark device) animals. For experimental animals, an Ark device was implanted approximately 10 cm downstream of the anastomosis at the time of AVF creation. Postoperative ultrasounds and cannulations of the jugular vein fistula were performed over 12 months. At the conclusion of the study, the AVF was ligated and Ark devices along with a segment of the arterialized vein and surrounding tissues were explanted for gross and histological assessment. The control and experimental Ark groups exhibited increased dilation and flow as well as diminished depth underscoring the parallel developments in vascular attributes and AVF maturation between the two groups. Gross pathology, histology, and micro-CT imaging revealed intact endothelium, mature tissue integration throughout the porous Ark device, and no underlying stenosis. No adverse events such as foreign body reaction, skin or vessel erosion were identified. The study showed maturation without stenosis of the fistula in all animals. This study confirmed that the Ark device functions as a scaffold around the access vein, allows fistula maturation, and can be consistently cannulated without infiltrations over a 12-month period in a large animal model.

Streamlining Preoperative Evaluation for Dialysis Access: A Pilot Study

Outpatient in-person clinic evaluation is the standard consultation practice for an initial referral for hemodialysis (HD) access. However, most factors predicting the complexity of first-time access surgery can be determined from history rather than physical exam. This study compares the outcomes of patients undergoing first-time arteriovenous fistula creation screened with a standardized preoperative phone interview and no preoperative clinic visit (SPEEDY group) to those opting for a standard in-person clinic visit. From September 2021 to August 2022, all patients scheduled in our vascular surgery clinic for first-time dialysis access were interviewed via telephone using a standardized history questionnaire. Those meeting criteria and expressing desire to bypass the initial clinic visit were scheduled for surgery without an in-person preoperative evaluation (SPEEDY group). The comparison group included patients who were study-eligible but desired to meet with the surgeon preoperatively. Time from referral to fistula creation, overall fistula patency rates, and the incidence of access-specific complications were compared between the 2 groups. Of the 107 patients contacted, 43 (40%) were study eligible. Of these eligible patients, 21 (49%) were scheduled for surgery without a preoperative visit, of whom 19 (90%) underwent surgery. Compared to eligible controls, SPEEDY patients had a younger median age (49.3years vs. 58.9, P=0.056) but similar median duration of HD prior to fistula creation. SPEEDY patients had a significantly shorter median time from initial referral to surgery than eligible controls (48days vs. 82, P=0.01). Incidence of complications did not differ between the groups. At a median follow up time of 18.3months (IQR 11.4-20.9) there was no difference in overall access patency between SPEEDY participants and eligible controls (P=0.83). A standardized telephone questionnaire can effectively be used to identify patients who can safely undergo first time dialysis access surgery without an in-person clinic evaluation, significantly reducing time from initial referral to surgery without increasing complications or compromising patency rates.

Effectiveness of autologous interposition saphenous graft in the creation of proximal arteriovenous fistula: Our initial experience

Abstract: For the individuals with end-stage renal disease, maintenance hemodialysis is a common treatment. When we compare to dialysis catheters or prosthetic grafts, arteriovenous fistula (AVF) is associated with a greater maturation period but a smaller incidence of infections, central venous stenosis, hospitalizations, and mortality. Fistulas mature by a dynamic process which is known as venous arterialization, where the breakdown of elastin and release of nitric oxide promote the functional and structural remodeling of the venous wall, permitting the expansion of venous outflow. Veins made them exposed to the arterial environment at the time of venous grafts and AVFs creation. Successful adaptation of the vein to the arterial flow is the most demanding part for long-term success, identified by venous dilation followed by wall thickening. Arteriovenous fistulas (AVF) and grafts (AV graft) are the commonest form of vascular access used for maintenance of hemodialysis. In general AVF is superior than AV graft in terms of its durability, patency, complication rate and overall survival of patients. But when the calibre of the vein is not satisfactory or length is not adequate to make tension free anastomosis, interposition graft is used. Most commonly used bridging material is polytetrafluoroethylene (PTFE) polymer. In this case, we used an interposition graft of the saphenous vein for making dialysis access on a 38 year old male patient having renal insufficiency and evaluated its efficacy in maintaining flow.

Informing Choices about Arteriovenous Fistula Creation: Insights from a Prospective Cohort Study

Informing Choices about Arteriovenous Fistula Creation: Insights from a Prospective Cohort Study