Mitochondrial targeted catalase improves muscle strength following arteriovenous fistula creation in mice with chronic kidney disease.

Hand dysfunction is a common observation after arteriovenous fistula (AVF) creation for hemodialysis access and has a variable clinical phenotype; however, the underlying mechanism responsible is unclear. Grip strength changes are a common metric used to assess AVF-associated hand disability but has previously been found to poorly correlate with the hemodynamic perturbations post-AVF placement implicating other tissue-level factors as drivers of hand outcomes. In this study, we sought to test if expression of a mitochondrial targeted catalase (mCAT) in skeletal muscle could reduce AVF-related limb dysfunction in mice with chronic kidney disease (CKD). Male and female C57BL/6J mice were fed an adenine-supplemented diet to induce CKD prior to placement of an AVF in the iliac vascular bundle. Adeno-associated virus was used to drive expression of either a green fluorescent protein (control) or mCAT using the muscle-specific human skeletal actin (HSA) gene promoter prior to AVF creation. As expected, the muscle-specific AAV-HSA-mCAT treatment did not impact blood urea nitrogen levels (P = 0.72), body weight (P = 0.84), or central hemodynamics including infrarenal aorta and inferior vena cava diameters (P > 0.18) or velocities (P > 0.38). Hindlimb perfusion recovery and muscle capillary densities were also unaffected by AAV-HSA-mCAT treatment. In contrast to muscle mass and myofiber size which were not different between groups, both absolute and specific muscle contractile forces measured via a nerve-mediated in-situ preparation were significantly greater in AAV-HSA-mCAT treated mice (P = 0.0012 and P = 0.0002). Morphological analysis of the post-synaptic neuromuscular junction uncovered greater acetylcholine receptor cluster areas (P = 0.0094) and lower fragmentation (P = 0.0010) in AAV-HSA-mCAT treated mice. Muscle mitochondrial oxidative phosphorylation was not different between groups, but AAV-HSA-mCAT treated mice had lower succinate-fueled mitochondrial hydrogen peroxide emission compared to AAV-HSA-GFP mice (P < 0.001). In summary, muscle-specific scavenging of mitochondrial hydrogen peroxide significantly improves neuromotor function in mice with CKD following AVF creation.

Factors Associated with Dialysis Initiation in Patients with Predialysis Arteriovenous Fistula.

INTRODUCTION: A large proportion of patients initiated hemodialysis with a central vein catheter rather than a permanent vascular access which was recommended by guidelines. One major barrier was the paucity of evidence regarding the optimal timing of vascular access creation in predialysis patients. METHODS: Our study prospectively enrolled 300 patients undergoing predialysis arteriovenous fistula (AVF) creation in our center from 2015 to 2018. Cox proportional hazard regression was performed to identify which demographic and clinical factors were associated with the initiation of hemodialysis after AVF surgery. A receiver operating characteristic area under the curve (AUC) was used to assess the predictive power of preoperative factors for the likelihood of hemodialysis initiation. RESULTS: Overall, 163 (54.3%), 214 (71.3%), and 275 (91.7%) patients initiated hemodialysis within 3 months, 6 months, and 1 year, respectively, after AVF creation. The median time between AVF creation and hemodialysis start was 71.5 days. Using multivariate Cox regression analysis, three factors were associated with hemodialysis initiation within 1 year: serum phosphorus (HR = 1.407, p = 0.021), diabetic kidney disease (DKD) (HR = 1.429, p = 0.039), and cystatin C (HR = 1.179, p = 0.009). Cystatin C alone had a moderate predictive value for dialysis initiation (AUC = 0.746; p < 0.001), whereas the full model had a higher predictive value (AUC = 0.800; p < 0.001). CONCLUSION: DKD, serum cystatin C, and phosphorus at access surgery were associated with hemodialysis initiation within 1 year of the predialysis AVF creation. Our findings provide a basis for a more customized approach to planning AVF placement in patients with chronic kidney disease.

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.

N-acetylcysteine treatment attenuates hemodialysis access-related limb pathophysiology in mice with chronic kidney disease.

The objective of the present study was to determine if treatment with N-acetylcysteine (NAC) could reduce access-related limb dysfunction in mice. Male and female C57BL6J mice were fed an adenine-supplemented diet to induce chronic kidney disease (CKD) prior to the surgical creation of an arteriovenous fistula (AVF) in the iliac vascular bundle. AVF creation significantly increased peak aortic and infrarenal vena cava blood flow velocities, but NAC treatment had no significant impact, indicating that fistula maturation was not impacted by NAC treatment. Hindlimb muscle and paw perfusion recovery and muscle capillary density in the AVF limb were unaffected by NAC treatment. However, NAC treatment significantly increased the mass of the tibialis anterior (P = 0.0120) and soleus (P = 0.0452) muscles post-AVF. There was a significant main effect of NAC treatment on hindlimb grip strength at postoperative day 12 (POD 12) (P = 0.0003), driven by significantly higher grip strength in both male (P = 0.0273) and female (P = 0.0031) mice treated with NAC. There was also a significant main effect of NAC treatment on the walking speed at postoperative day 12 (P = 0.0447), and post hoc testing revealed an improvement in NAC-treated male mice (P = 0.0091). The area of postsynaptic acetylcholine receptors (P = 0.0263) and motor endplates (P = 0.0240) was also increased by NAC treatment. Interestingly, hindlimb skeletal muscle mitochondrial oxidative phosphorylation trended higher in NAC-treated female mice but was not statistically significant (P = 0.0973). Muscle glutathione levels and redox status were not significantly impacted by NAC treatment in either sex. In summary, NAC treatment attenuated some aspects of neuromotor pathology in mice with chronic kidney disease following AVF creation.NEW & NOTEWORTHY Hemodialysis via autogenous arteriovenous fistula (AVF) is the preferred first-line modality for renal replacement therapy in patients with end-stage kidney disease. However, patients undergoing AVF surgery frequently experience a spectrum of hand disability symptoms postsurgery including weakness and neuromotor dysfunction. Unfortunately, no treatment is currently available to prevent or mitigate these symptoms. Here, we provide evidence that daily N-acetylcysteine supplementation can attenuate some aspects of limb neuromotor function in a preclinical mouse model of AVF.

The Effect of Acupressure and Cryotherapy on the Pain of Patients on Hemodialysis During Arteriovenous Fistula Cannulation: A Randomized Crossover Clinical Trial.

Various pharmacological and non-pharmacological measures are used to reduce pain of patients on hemodialysis during an arteriovenous fistula (AVF) cannulation. In this randomized, crossover clinical trial, 39 patients randomly received acupressure and cryotherapy. In cryotherapy, an ice cube was used to massage the Hegu point in the hand without the fistula for 10 minutes before AVF cannulation. In acupressure, a moderate pressure with the thumb was applied. The pain score was mild after cryotherapy and acupressure, with no significant difference between the two methods. In addition, acupressure significantly reduced pain compared with routine care, but cryotherapy did not significantly reduce pain compared with routine care. Pain intensity was mild after acupressure and cryotherapy, and neither of these two methods was preferred over the other to reduce the pain during AVF cannulation.

Evaluation of outcomes with permanent vascular access in an elderly Korean population based on the National Health Insurance Service database.

INTRODUCTION: As nearly half of patients with end-stage kidney disease (ESKD) who initiate hemodialysis (HD) are over 65 years old (commonly defined as elderly), the fistula first strategy is controversial even in HD patients ≥65 years. METHODS: In Korea's National Health Insurance Service database from 2008 to 2019, 41,989 elderly (≥ 65 years) HD patients were retrospectively reviewed to identify their clinical characteristics and outcomes. Vascular access (VA) patencies, risk factors associated with patencies and patient survival between arteriovenous fistula (AVF) and arteriovenous graft (AVG) were compared. RESULTS: Elderly AVF group (n = 28,467) had superior primary, primary assisted, and secondary patencies than elderly AVG group (n = 13,522) (all p values are <0.001). Patient survival was also better in the elderly AVF group than in the elderly AVG (p < 0.001). In multivariate Cox regression analyses for diverse outcomes, AVG (vs. AVF) was identified as a risk factor for all-cause mortality (adjusted hazard ratio [HR]: 1.307; 95% confidence interval [CI]: 1.272-1.343; p < 0.001), primary patency (adjusted HR: 1.745; 95% CI: 1.701-1.790; p < 0.001), primary-assisted patency (adjusted HR: 2.163; 95% CI: 2.095-2.233; p < 0.001), and secondary patency (adjusted HR: 3.718; 95% CI: 3.533-3.913; p < 0.001). CONCLUSION: Our study demonstrated that as a permanent VA for HD, AVF should be strongly considered in elderly (≥ 65 years) ESKD Korean patients. The age limit for AVF creation in ESKD patients should be adjusted more upward.

Metabolomic profiling reveals muscle metabolic changes following iliac arteriovenous fistula creation in mice.

End-stage kidney disease, the most advanced stage of chronic kidney disease (CKD), requires renal replacement therapy or kidney transplant to sustain life. To accomplish durable dialysis access, the creation of an arteriovenous fistula (AVF) has emerged as a preferred approach. Unfortunately, a significant proportion of patients that receive an AVF experience some form of hand dysfunction; however, the mechanisms underlying these side effects are not understood. In this study, we used nuclear magnetic resonance spectroscopy to investigate the muscle metabolome following iliac AVF placement in mice with CKD. To induce CKD, C57BL6J mice were fed an adenine-supplemented diet for 3 wk and then randomized to receive AVF or sham surgery. Two weeks following surgery, the quadriceps muscles were rapidly dissected and snap frozen for metabolite extraction and subsequent nuclear magnetic resonance analysis. Principal component analysis demonstrated clear separation between groups, confirming a unique metabolome in mice that received an AVF. AVF creation resulted in reduced levels of creatine, ATP, and AMP as well as increased levels of IMP and several tricarboxylic acid cycle metabolites suggesting profound energetic stress. Pearson correlation and multiple linear regression analyses identified several metabolites that were strongly linked to measures of limb function (grip strength, gait speed, and mitochondrial respiration). In summary, AVF creation generates a unique metabolome profile in the distal skeletal muscle indicative of an energetic crisis and myosteatosis.NEW & NOTEWORTHY Creation of an arteriovenous fistula (AVF) is the preferred approach for dialysis access, but some patients experience hand dysfunction after AVF creation. In this study, we provide a detailed metabolomic analysis of the limb muscle in a murine model of AVF. AVF creation resulted in metabolite changes associated with an energetic crisis and myosteatosis that associated with limb function.

Pain after Arteriovenous Access Creation.

OBJECTIVES: Dialysis access creation is a common outpatient procedure that can be completed using general, regional, or local anesthetic techniques. There are few endorsed guidelines regarding opioid-based pain control following fistula creation. The purpose of this study was to determine whether utilization of regional anesthesia (RA) is associated with the decreased use of narcotics postoperatively. METHODS: We performed a prospective cohort study including all patients undergoing arteriovenous fistula creation with one vascular surgeon from August 2019 to February 2020. Patients were selected for regional versus general anesthesia. Selection for anesthesia type was determined by the primary anesthesiologist. Patients selected for RA underwent supraclavicular brachial plexus block with 30 cm3 of 0.5% ropivacaine. Patients were seen in clinic follow-up and completed a questionnaire regarding their postoperative opiate use and pain control. RESULTS: In the study period, 52 patients underwent arteriovenous fistula creation and completed the follow-up questionnaire. Forty patients received RA. Seventy-five percent of patients sent home with a narcotic prescription filled the prescription. There was a significant difference in postoperative opioid use between the two study groups. Patients who received regional block took on average 3.3 pills totaling 16.5 morphine milligram equivalents, whereas patients who received general anesthesia took on average 6.64 pills totaling 33.2 morphine milligram equivalents (P = 0.04). CONCLUSIONS: Morbidity and mortality related to opiate use continues to be a public health issue in the United States. This study demonstrates that regional anesthetic techniques in comparison to general anesthesia can result in a significant decrease in postoperative opiate consumption.

Music Therapy in Dialysis Access Procedures With Moderate Sedation.

BACKGROUND: The aim was to evaluate the effects of music on patients' anxiety and satisfaction after undergoing dialysis access procedures under moderate sedation. METHODS: Patients (n = 30) undergoing moderate sedation for dialysis access procedures were evaluated at a single institution. Each patient filled out a survey preoperatively and postoperatively using the short form State-Trait Anxiety Inventory (STAI-6). Patient-selected music was provided by using a MP3 player with noise canceling headphones. RESULTS: Postoperatively, 77% of patients perceived music intervention as very or extremely helpful in decreasing anxiety during the procedure. Further, 93% of patients were somewhat or very satisfied with their procedure. The average pain rating was 3.1 on a scale of 0-10, in which 70% of patients had no to mild pain and 30% of patients rated moderate to severe pain. In comparison to prior procedures without music, 63% of patients rated better experience with the music intervention, 37% rated a similar experience, and 3.7% rated having a worse experience. Approximately, 93% of patients were willing to repeat procedure with music and would recommend it to other patients. Preoperative anxiety average score was 35.6 ± 13 and was reduced postoperatively to 28.9 ± 12.9 (P = .006). Preoperatively, 23% of patients rated high anxiety and postoperatively only 6.7% of patients rated high anxiety (P = .016). CONCLUSION: Music is an easy, feasible, inexpensive intervention that may reduce patients' anxiety and improve satisfaction during moderate sedation procedures and in the postoperative period.

Ultrasound-Guided Cradle-Like Infiltrative Anesthesia for Percutaneous Transluminal Angioplasty of Stenotic Autogenous Arteriovenous Hemodialysis Access.

BACKGROUND: Percutaneous transluminal angioplasty (PTA) is an effective treatment for autogenous arteriovenous hemodialysis access (AAVA) stenosis; however, it causes pain in most cases. Therefore, safe and effective anesthesia for PTA is required. METHODS: We introduced a method of ultrasound-guided cradle-like infiltration anesthesia (UCIA) to administer analgesia during PTA. Using ultrasound guidance, 1% lidocaine was injected into the bilateral and inferior perivascular spaces of the stenosis to form a cradle-like region. In this study, 100 consecutive patients were divided into two groups, and the analgesic effect of UCIA was evaluated using a numerical rating scale with non-ultrasound-guided infiltration anesthesia as a control. Meanwhile, we compared the effect of PTA between the two groups with the postoperative internal diameter of the stenosis. RESULTS: The numerical rating scale score was 4.6 ± 1.9 and 2.0 ± 1.6 (P < 0.001) in UCIA group and non-ultrasound-guided infiltration anesthesia group, respectively. The postoperative internal diameter of stenosis was 3.9 ± 0.6 mm and 4.1 ± 0.7 mm (P = 0.113); the postoperative AAVA flow volume was 627 ± 176 mL/min and 644 ± 145 mL/min (P = 0.600). CONCLUSIONS: This study preliminarily showed that UCIA is effective and safe for the analgesia of AAVA PTA.

Anaesthesia Choice for Creation of Arteriovenous Fistula (ACCess) study protocol : a randomised controlled trial comparing primary unassisted patency at 1 year of primary arteriovenous fistulae created under regional compared to local anaesthesia.

INTRODUCTION: Arteriovenous fistulae (AVF) are the 'gold standard' vascular access for haemodialysis. Universal usage is limited, however, by a high early failure rate. Several small, single-centre studies have demonstrated better early patency rates for AVF created under regional anaesthesia (RA) compared with local anaesthesia (LA). The mechanistic hypothesis is that the sympathetic blockade associated with RA causes vasodilatation and increased blood flow through the new AVF. Despite this, considerable variation in practice exists in the UK. A high-quality, adequately powered, multicentre randomised controlled trial (RCT) is required to definitively inform practice. METHODS AND ANALYSIS: The Anaesthesia Choice for Creation of Arteriovenous Fistula (ACCess) study is a multicentre, observer-blinded RCT comparing primary radiocephalic/brachiocephalic AVF created under regional versus LA. The primary outcome is primary unassisted AVF patency at 1 year. Access-specific (eg, stenosis/thrombosis), patient-specific (including health-related quality of life) and safety secondary outcomes will be evaluated. Health economic analysis will also be undertaken. ETHICS AND DISSEMINATION: The ACCess study has been approved by the West of Scotland Research and ethics committee number 3 (20/WS/0178). Results will be published in open-access peer-reviewed journals within 12 months of completion of the trial. We will also present our findings at key national and international renal and anaesthetic meetings, and support dissemination of trial outcomes via renal patient groups. TRIAL REGISTRATION NUMBER: ISRCTN14153938. SPONSOR: NHS Greater Glasgow and Clyde GN19RE456, Protocol V.1.3 (8 May 2021), REC/IRAS ID: 290482.

Medical adjuvant treatment to increase patency of arteriovenous fistulae and grafts.

BACKGROUND: People with end-stage renal disease (ESRD) often require either the formation of an arteriovenous fistula (AVF) or an interposition prosthetic arteriovenous graft (AVG) for haemodialysis. These access sites should ideally have a long life and a low rate of complications (e.g. thrombosis, infection, stenosis, aneurysm formation and distal limb ischaemia). Although some of the complications may be unavoidable, any adjuvant technique or medical treatment aimed at decreasing complications would be welcome. This is the fourth update of the review first published in 2003. OBJECTIVES: To assess the effects of adjuvant drug treatment in people with ESRD on haemodialysis via autologous AVFs or prosthetic interposition AVGs. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and ClinicalTrials.gov trials register to 6 August 2020. SELECTION CRITERIA: Randomised controlled trials of active drug versus placebo in people with ESRD undergoing haemodialysis via an AVF or prosthetic interposition AVG. DATA COLLECTION AND ANALYSIS: For this update, two review authors (IM, MFAK) independently selected trials for inclusion, extracted data, assessed risk of bias and assessed the certainty of the evidence according to GRADE. We resolved disagreements by discussion or consultation with another review author (ADS). The primary outcome was the long-term fistula or graft patency rate. Secondary outcomes included duration of hospital stay; complications such as infection, aneurysm formation, stenosis and distal limb ischaemia; and number of related surgical or radiological interventions. MAIN RESULTS: For this update, one additional study was suitable for inclusion, making a total of 13 trials with 2080 participants. Overall the certainty of the evidence was low or moderate due to short follow-up periods, heterogeneity between trials, small sample sizes, and risk of bias due to incomplete reporting. Medical adjuvant treatments used in the included trials were aspirin, ticlopidine, dipyridamole, dipyridamole plus aspirin, warfarin, fish oil, clopidogrel, sulphinpyrazone and glyceryl trinitrate (GTN) patch.  All included studies reported on graft patency by measuring graft thrombosis. There was insufficient evidence to determine if there was a difference in graft patency in studies comparing aspirin versus placebo (odds ratio (OR) 0.40, 95% confidence interval (CI) 0.07 to 2.25; 3 studies, 175 participants; low-certainty evidence). The meta-analysis for graft patency comparing ticlopidine versus placebo favoured ticlopidine (OR 0.45, 95% CI 0.25 to 0.82; 3 studies, 339 participants; moderate-certainty evidence). There was insufficient evidence to determine if there was a difference in graft patency in studies comparing fish oil versus placebo (OR 0.24, 95% CI 0.03 to 1.95; 2 studies, 220 participants; low-certainty evidence); and studies comparing clopidogrel and placebo (OR 0.40, 95% CI 0.13 to 1.19; 2 studies, 959 participants; moderate-certainty evidence). Similarly, there was insufficient evidence to determine if there was a difference in graft patency comparing the effect of dipyridamole versus placebo (OR 0.46, 95% CI 0.11 to 1.94; 1 study, 42 participants, moderate-certainty evidence) and dipyridamole plus aspirin versus placebo (OR 0.64, CI 0.16 to 2.56; 1 study, 41 participants; moderate-certainty evidence); comparing low-intensity warfarin with placebo (OR 1.76, 95% CI 0.78 to 3.99; 1 study, 107 participants; low-certainty evidence); comparing sulphinpyrazone versus placebo (OR 0.43, 95% CI 0.03 to 5.98; 1 study, 16 participants; low-certainty evidence) and comparing GTN patch and placebo (OR 1.26, 95% CI 0.63 to 2.54; 1 study, 167 participants; moderate-certainty evidence). The single trial evaluating warfarin was terminated early because of major bleeding events in the warfarin group. Only two studies published data on the secondary outcome of related interventions (surgical or radiological); there was insufficient evidence to determine if there was a difference in related interventions between placebo and treatment groups. None of the included studies reported on the duration of hospital stay.  Most studies reported complications ranging from mortality to nausea. However, data on complications were limited and reporting varied between studies. AUTHORS' CONCLUSIONS: The meta-analyses of three studies for ticlopidine (an antiplatelet treatment), which all used the same dose of treatment but with a short follow-up of only one month, suggest ticlopidine may have a beneficial effect as an adjuvant treatment to increase the patency of AVFs and AVGs in the short term. There was insufficient evidence to determine if there was a difference in graft patency between placebo and other treatments such as aspirin, fish oil, clopidogrel, dipyridamole, dipyridamole plus aspirin, warfarin, sulphinpyrazone and GTN patch. The certainty of the evidence was low to moderate due to short follow-up periods, the small number of studies for each comparison, small sample sizes, heterogeneity between trials and risk of bias due to incomplete reporting. Therefore, it appears reasonable to suggest further prospective studies be undertaken to assess the use of these antiplatelet drugs in renal patients with an AVF or AVG.

Device Therapy of Hypertension.

In the past decade, efforts to improve blood pressure control have looked beyond conventional approaches of lifestyle modification and drug therapy to embrace interventional therapies. Based upon animal and human studies clearly demonstrating a key role for the sympathetic nervous system in the etiology of hypertension, the newer technologies that have emerged are predominantly aimed at neuromodulation of peripheral nervous system targets. These include renal denervation, baroreflex activation therapy, endovascular baroreflex amplification therapy, carotid body ablation, and pacemaker-mediated programmable hypertension control. Of these, renal denervation is the most mature, and with a recent series of proof-of-concept trials demonstrating the safety and efficacy of radiofrequency and more recently ultrasound-based renal denervation, this technology is poised to become available as a viable treatment option for hypertension in the foreseeable future. With regard to baroreflex activation therapy, endovascular baroreflex amplification, carotid body ablation, and programmable hypertension control, these are developing technologies for which more human data are required. Importantly, central nervous system control of the circulation remains a poorly understood yet vital component of the hypertension pathway and mandates further investigation. Technology to improve blood pressure control through deep brain stimulation of key cardiovascular control territories is, therefore, of interest. Furthermore, alternative nonsympathomodulatory intervention targeting the hemodynamics of the circulation may also be worth exploring for patients in whom sympathetic drive is less relevant to hypertension perpetuation. Herein, we review the aforementioned technologies with an emphasis on the preclinical data that underpin their rationale and the human evidence that supports their use.

Effectiveness of Flow Volume Measurement Training Using a Custom-Made Doppler Flow Simulator.

INTRODUCTION: This study was conducted to analyze the effectiveness of a custom-made Doppler ultrasound (DUS) flow simulator, vascular phantom, and Doppler test fluid in the training of dialysis staff in flow volume (FV) measurements for arteriovenous (AV) access in hemodialysis (HD) patients. METHODS: A DUS flow simulator was constructed using a continuous renal replacement therapy machine. Vascular phantoms were constructed using a rubber enema tube and keyboard cleaning gel. The Doppler test fluid consisted of freeze-dried instant coffee granules and 0.9% saline. This easy and affordable simulator was used to train 12 dialysis staff members, with no previous experience in DUS FV measurement. After a 3-day lecture course, the staff members performed DUS analyses on the AV access of HD patients. Thereafter, they underwent a 3-day training course using the simulator and then performed the DUS analyses of the AV access again. Each staff member assessed the FV 3 times, and the mean values of the measurements pretraining and posttraining were analyzed using paired t tests. RESULTS: The difference in the mean value of FV measurements and the reference value decreased from 131.6 mL/min to 62.5 mL/min (95% confidence interval = 30.0-108.0, P = 0.002), and the standard deviation of the FV measurements decreased from 96.9 mL/min to 47.0 mL/min (95% confidence interval = 7.9-91.8, P = 0.023) after DUS training with the simulator. CONCLUSIONS: The accuracy and reproducibility of FV measurements markedly improved after training with the simulator; it may be helpful for medical practitioners involved in AV access for HD treatment.

Cost-effectiveness analysis of immediate access arteriovenous grafts versus standard grafts for hemodialysis.

OBJECTIVE: Immediate-access arteriovenous grafts (IAAVGs), or early cannulation arteriovenous grafts (AVGs), are more expensive than standard grafts (sAVGs) but can be used immediately after placement, reducing the need for a tunneled dialysis catheter (TDC). We hypothesized that a decrease in TDC-related complications would make IAAVGs a cost-effective alternative to sAVGs. METHODS: We constructed a Markov state-transition model in which patients initially received either an IAAVG or an sAVG and a TDC until graft usability; patients were followed through multiple subsequent access procedures for a 60-month time horizon. The model simulated mortality and typical graft- and TDC-related complications, with parameter estimates including probabilities, costs, and utilities derived from previous literature. A key parameter was median time to TDC removal after graft placement, which was studied under both real-world (7 days for IAAVG and 70 days for sAVG) and ideal (no TDC placed with IAAVG and 1 month for sAVG) conditions. Costs were based on current Medicare reimbursement rates and reflect a payer perspective. Both microsimulation (10,000 trials) and probabilistic sensitivity analysis (10,000 samples) were performed. The willingness-to-pay threshold was set at $100,000 per quality-adjusted life-year (QALY). RESULTS: IAAVG placement is a dominant strategy under both real-world ($1201.16 less expensive and 0.03 QALY more effective) and ideal ($1457.97 less expensive and 0.03 QALY more effective) conditions. Under real-world parameters, the result was most sensitive to the time to TDC removal; IAAVGs are cost-effective if a TDC is maintained for ≥23 days after sAVG placement. The mean catheter time was lower with IAAVG (3.9 vs 8.7 months; P < .0001), as was the mean number of access-related infections (0.55 vs 0.74; P < .0001). Median survival in the model was 29 months. Overall mortality was similar between groups (76.3% vs 76.7% at 5 years; P = .33), but access-related mortality trended toward improvement with IAAVG (6.1% vs 6.8% at 5 years; P = .052). CONCLUSIONS: The Markov decision analysis model supported our hypothesis that IAAVGs come with added initial cost but are ultimately cost-saving and more effective. This apparent benefit is due to our prediction that a decreased number of catheter days per patient would lead to a decreased number of access-related infections.

Optimal Time of Thermotherapy for Reducing Pain, Anxiety, and Side Effects in Arteriovenous Fistula Puncture Patients: A Randomized Controlled Trial.

Chronic renal failure patients undergoing hemodialysis complain of moderate pain from repeated punctures of the arteriovenous fistula. This study examined the optimal application time of thermotherapy for reducing pain, anxiety, and side effects during arteriovenous fistula puncture. This study was conducted as a single-blinded randomized controlled trial. The participants were arteriovenous fistula puncture patients with chronic renal failure who were divided into two thermotherapy groups and one control group. This study was approved by the institutional review board and registered with the Clinical Research Information Service (KCT0003768). Differences between groups regarding pain, anxiety, and side effects were analyzed using one-way ANOVA, the χ2 test, and the Scheffé test. A significant difference was observed between the 10-min and 20-min thermotherapy groups and the control group in terms of the pain they experienced. Additionally, more side effects were encountered in the 20-min thermotherapy group than in the 10-min group. The 10-min application of thermotherapy for an arteriovenous fistula puncture showed the same pain-reducing effect as the conventional 20-min application. The study confirmed a 10-min application of thermotherapy to be an effective nursing intervention for pain relief without side effects.

The effects of eugenol nanoemulsion on pain caused by arteriovenous fistula cannulation in hemodialysis patients: A randomized double-blinded controlled cross-over trial.

OBJECTIVES: Local anesthetic and antinociceptive activity of eugenol, as the main ingredient of clove, was determined in previous researches. This study aimed to assess the efficacy of its topical nanoemulsion gel vs. placebo in controlling pain caused by arteriovenous fistula (AVF) needling in patients undergoing hemodialysis (HD). DESIGN: In this double-blinded cross-over trial, the patients were randomly allocated to eugenol gel 4% (n = 34) and placebo gel (n  = 34) groups. For each patient, a tip of finger unit of gel was applied 2 cm around the insertion site of hemodialysis needles. After 10 min, AVF needling was done. AVF needling-related pain was assessed using visual analogue scale (VAS) immediately after the puncture. All patients were tested at three different states: (1) before using any intervention; (2) after using either the eugenol or placebo gel; and (3) after crossing over the groups. RESULTS: There was a significant difference between the mean of patients' pain severity score in the three states (p = 0.001). It was reported as low as 3.29 ±â€¯0.67 in patients who received eugenol nanoemulsion. Also, the highest pain severity score (5.03 ±â€¯0.57) was reported at the no-intervention state. CONCLUSIONS: It seems that topical application of eugenol nanoemulsion may significantly decrease AVF cannulation related pain intensity score in patients undergoing HD. However, further studies with larger sample size and longer intervention period should be done for better judgment on its efficiency and safety.

Comparison of regional and local anesthesia for arteriovenous fistula creation in end-stage renal disease: a systematic review and meta-analysis.

BACKGROUND: Arteriovenous fistulae (AVF) are the hemodialysis access modality of choice for patients with end-stage renal disease. However, they have a high early failure rate. Good vascular access is essential to manage long-term hemodialytic treatment, but some anesthesia techniques directly affect venous diameter as well as intra- and post-operative blood flow. The main purpose of this meta-analysis was to compare the results of regional and local anesthesia (RA and LA) for arteriovenous fistula creation in end-stage renal disease. METHODS: We conducted a systematic review and meta-analysis to synthesize evidence from 7 randomized controlled trials (565 patients) and 1 observational study (408 patients) with the aim of evaluating the safety and efficacy of RA versus LA in surgical construction of AVF. RESULTS: Pooled data showed that RA was associated with higher primary patency rates than LA (odds ratio [OR], 1.88; 95% confidence interval [CI]: 1.24-2.84; P = 0.003; I2 = 31%). Additionally, brachial artery diameter was significantly increased in the RA versus LA group (mean difference [MD], 0.83; 95% CI: 0.75-0.92; P < 0.001; I2 = 97%) and the need for intra- as well as post-operative pain killers was significantly less (RA, P = 0.0363; LA, P = 0.0318). Moreover, operation duration was significantly reduced using RA versus LA (MD, - 29.63; 95% CI: - 32.78 - -26.48; P < 0.001; I2 = 100%). CONCLUSIONS: This meta-analysis suggests that RA is preferable to LA in patients with end-stage renal disease in guaranteeing AVF patency and increasing brachial artery diameter.

Ferumoxytol MR Angiography versus Duplex US for Vascular Mapping before Arteriovenous Fistula Surgery for Hemodialysis.

Background Duplex US is performed routinely for vascular mapping prior to arteriovenous fistula (AVF) creation for hemodialysis but cannot demonstrate the central vasculature. Ferumoxytol, an iron oxide nanoparticle, provides an alternative to gadolinium contrast material for MR angiography for safe use in chronic kidney disease (CKD). Purpose To assess the clinical utility of ferumoxytol-enhanced MR angiography compared with duplex US for vascular mapping before upper limb AVF creation in participants with CKD. Materials and Methods In a prospective comparative study (ClinicalTrials.gov: NCT02997046) from December 2016 to August 2018, participants with CKD underwent ferumoxytol-enhanced MR angiography and duplex US. Two independent readers evaluated vessels for diameter, stenosis or occlusion, arterial disease, and central stenosis. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to assess intra- and interreader variability. On the basis of accepted standards for AVF creation, an algorithm was developed to predict AVF outcome based on imaging findings. Multivariable regression models used AVF success as the dependent variable and age, sex, and duplex US or ferumoxytol-enhanced MR angiography findings as independent variables. Results Fifty-nine participants with CKD (mean age, 59 years ± 13 [standard deviation]; 30 women) were evaluated. A total of 51 fistulas were created, of which 24 (47%) were successful. Ferumoxytol-enhanced MR angiography showed excellent inter- and intrareader repeatability (ICC, 0.84-0.99) for all variables assessed. In addition to revealing 15 central vasculature stenoses, ferumoxytol-enhanced MR angiography resulted in characterization of 88 of 236 (37%) of the arterial sections examined as unsuitable for AVF creation compared with 61 of 236 (26%) sections with duplex US (P = .01). Ferumoxytol-enhanced MR angiography independently predicted AVF success in models including (odds ratio, 6.5; 95% confidence interval: 1.7, 25; P = .006) and those excluding (odds ratio, 4.6; 95% confidence interval: 1.3, 17; P = .02) the central vasculature. Conclusion In addition to enabling identification of central vessel pathologic features, ferumoxytol-enhanced MR angiography revealed peripheral arterial disease not recognized with duplex US and was more predictive than duplex US of the outcome of arteriovenous fistula surgery. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Finn in this issue.