Fibroblast growth factor 21 predicts arteriovenous fistula functional patency loss and mortality in patients undergoing maintenance hemodialysis

BACKGROUND

Arteriovenous fistula (AVF) dysfunction is a common complication in patients undergoing maintenance hemodialysis (MHD). Elevated serum levels of fibroblast growth factor 21 (FGF21) are associated with atherosclerosis and cardiovascular mortality. However, its association with vascular access outcomes remains elusive. The present study evaluated the relationship of serum FGF21 levels with AVF dysfunction and all-cause mortality in patients undergoing MHD.

METHODS

We included patients undergoing MHD using AVF from January 2018 to December 2019. FGF21 concentration was detected using enzyme-linked immunosorbent assay. Patients were followed up to record two clinical outcomes, AVF functional patency loss and all-cause mortality. The follow-up period ended on April 30, 2022.

RESULTS

Among 147 patients, the mean age was 58.49 ± 14.41 years, and the median serum level of FGF21 was 150.15 (70.57-318.01) pg/mL. During the median follow-up period of 40.83 months, the serum level of FGF21 was an independent risk factor for AVF functional patency loss (per 1 pg/mL increase, HR 1.002 [95% CI: 1.001-1.003, p = 0.003]). Patients with higher serum levels of FGF21 were more likely to suffer from all-cause mortality (per 1 pg/mL increase, HR 1.002 [95% CI: 1.000-1.003, p = 0.014]). The optimal cutoffs for FGF21 to predict AVF functional patency loss and all-cause mortality in patients undergoing MHD were 149.98 pg/mL and 146.43 pg/mL, with AUCs of 0.701 (95% CI: 0.606-0.796, p < 0.001) and 0.677 (95% CI: 0.595-0.752, p = 0.002), respectively.

CONCLUSIONS

Serum FGF21 levels were an independent risk factor and predictor for AVF functional patency loss and all-cause mortality in patients undergoing MHD.

Computational fluid-structure interaction analysis of the end-to-side radio-cephalic arteriovenous fistula

BACKGROUND AND OBJECTIVE

In the current work, we present a descriptive fluid-structure interaction computational study of the end-to-side radio-cephalic arteriovenous fistula. This allows us to account for the different thicknesses and elastic properties of the radial artery and cephalic vein.

METHODS

The core of the work consists in simulating different arteriovenous fistula configurations obtained by virtually varying the anastomosis angle, i.e. the angle between the end of the cephalic vein and the side of the radial artery. Since the aim of the work is to understand the blood dynamics in the very first days after the surgical intervention, the radial artery is considered stiffer and thicker than the cephalic vein.

RESULTS

Our results demonstrate that both the diameter of the cephalic vein and the anastomosis angle play a crucial role to obtain a blood dynamics without re-circulation regions that could prevent fistula failure.

CONCLUSIONS

When an anastomosis angle close to the perpendicular direction with respect to the radial artery is combined with a large diameter of the cephalic vein, the recirculation regions and the low Wall Shear Stress (WSS) zones are reduced. Conversely, from a structural point of view, a low anastomosis angle with a large diameter of the cephalic vein reduces the mechanical stress acting on the vessel walls.

Evaluation of arteriovenous fistula for hemodialysis with a new generation digital stethoscope: a pilot study

BACKGROUND AND AIMS

The management of complications of arteriovenous fistula (AVF) for hemodialysis, principally stenosis, remains a major challenge for clinicians with a substantial impact on health resources. Stenosis not infrequently preludes to thrombotic events with the loss of AVF functionality. A functioning AVF, when listened by a stethoscope, has a continuous systolic-diastolic low-frequency murmur, while with stenosis, the frequency of the murmur increases and the duration of diastolic component decreases, disappearing in severe stenosis. These evidences are strictly subjective and dependent from operator skill and experience. New generation digital stethoscopes are able to record sound and subsequently dedicated software allows to extract quantitative variables that characterize the sound in an absolutely objective and repeatable way. The aim of our study was to analyze with an appropriate software sounds from AVFs taken by a commercial digital stethoscope and to investigate the potentiality to develop an objective way to detect stenosis.

METHODS

Between September 2022 and January 2023, 64 chronic hemodialysis (HD) patients were screened by two blinded experienced examiners for recognized criteria for stenosis by Doppler ultrasound (DUS) and, consequently, the sound coming from the AVFs using a 3 M™ Littmann® CORE Digital Stethoscope 8570 in standardized sites was recorded. The sound waves were transformed into quantitative variables (amplitude and frequency) using a sound analysis software. The practical usefulness of the core digital stethoscope for a quick identification of an AVF stenosis was further evaluated through a pragmatic trial. Eight young nephrologist trainees underwent a simple auscultatory training consisting of two sessions of sound auscultation focusing two times on a "normal" AVF sound by placing the digital stethoscope on a convenience site of a functional AVF.

RESULTS

In 48 patients eligible, all sound components displayed, alone, a remarkable diagnostic capacity. More in detail, the AUC of the average power was 0.872 [95% CI 0.729-0.951], while that of the mean normalized frequency was 0.822 [95% 0.656-0.930]. From a total of 32 auscultations (eight different block sequences, each one comprising four auscultations), the young clinicians were able to identify the correct sound (stenosis/normal AVF) in 25 cases, corresponding to an overall accuracy of 78.12% (95% CI 60.03-90.72%).

CONCLUSIONS

The analysis of sound waves by a digital stethoscope permitted us to distinguish between stenotic and no stenotic AVFs. The standardization of this technique and the introducing of data in a deep learning algorithm could allow an objective and fast method for a frequent monitoring of AVF.

Retrospective analysis of predictive factors for AVF dysfunction in patients undergoing MHD

To construct an early clinical prediction model for AVF dysfunction in patients undergoing Maintenance Hemodialysis (MHD) and perform internal and external verifications. We retrospectively examined clinical data from 150 patients diagnosed with MHD at Hefei Third People's Hospital from January 2014 to June 2023. Depending on arteriovenous fistula (AVF) functionality, patients were categorized into dysfunctional (n = 62) and functional (n = 88) cohorts. Using the least absolute shrinkage and selection operator(LASSO) regression model, variables potentially influencing AVF functionality were filtered using selected variables that underwent multifactorial logistic regression analysis. The Nomogram model was constructed using the R software, and the Area Under Curve(AUC) value was calculated. The model's accuracy was appraised through the calibration curve and Hosmer-Lemeshow test, with the model undergoing internal validation using the bootstrap method. There were 11 factors exhibiting differences between the group of patients with AVF dysfunction and the group with normal AVF function, including age, sex, course of renal failure, diabetes, hyperlipidemia, Platelet count (PLT), Calcium (Ca), Phosphorus, D-dimer (D-D), Fibrinogen (Fib), and Anastomotic width. These identified factors are included as candidate predictive variables in the LASSO regression analysis. LASSO regression identified age, sex, diabetes, hyperlipidemia, anastomotic diameter, blood phosphorus, and serum D-D levels as 7 predictive factors. Unconditional binary logistic regression analysis revealed that advanced age (OR = 4.358, 95% CI: 1.454-13.062), diabetes (OR = 4.158, 95% CI: 1.243-13.907), hyperlipidemia (OR = 3.651, 95% CI: 1.066-12.499), D-D (OR = 1.311, 95% CI: 1.063-1.616), and hyperphosphatemia (OR = 4.986, 95% CI: 2.513-9.892) emerged as independent risk factors for AVF dysfunction in MHD patients. The AUC of the predictive model was 0.934 (95% CI: 0.897-0.971). The Hosmer-Lemeshow test showed high consistency between the model's predictive results and actual clinical observations (χ2 = 1.553, P = .092). Internal validation revealed an AUC of 0.911 (95% CI: 0.866-0.956), with the Calibration calibration curve nearing the ideal curve. Advanced age, coexisting diabetes, hyperlipidemia, blood D-D levels, and hyperphosphatemia are independent risk factors for AVF dysfunction in patients undergoing MHD.

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.

Personalised stroke evaluation and management: tailoring individualised patient care for hereditary haemorrhagic telangiectasia

SummaryHereditary haemorrhagic telangiectasia (HHT) has an estimated prevalence of 1 in 5000-8000 individuals globally with pulmonary arteriovenous malformations (PAVMs) affecting approximately 15%-50% of HHT patients. Ischaemic stroke is a known complication of PAVMs that affects ≤30% of patients with PAVMs. Studies have shown that patients with PAVMs have ischaemic stroke a decade earlier than routine stroke. The predominant mechanism of ischaemic stroke in HHT patients is paradoxical embolism due to PAVMs, but most HHT-related PAVMs are asymptomatic. Additionally, HHT is often underdiagnosed in patients and poses a challenge to physicians due to its rarity. We present a case of a patient with ischaemic stroke who was subsequently diagnosed with HHT and found to have a PAVM on further evaluation. This case highlights the importance of using an individualised patient-centred stroke evaluation and screening for PAVMs in patients who had a stroke with possible or suspected HHT and definite HHT.

Hemodialysis nurses' knowledge, attitude, and practices in managing vascular access: A cross-sectional study in Saudi Arabia

Hemodialysis continues to be the primary approach for renal replacement therapy. Vascular access (VA), particularly arteriovenous fistula or arteriovenous graft, is the preferred technique for establishing hemodialysis access due to its lower risk of infection and central venous stenosis compared to catheters. The aim of this cross-sectional investigation was to examine hemodialysis nurses' knowledge, confidence, and practices in managing VA in Saudi Arabia. This is an online cross-sectional survey study that was conducted in Saudi Arabia between June and August 2023. This study utilized a previously validated questionnaire. Examined dialysis nurses' knowledge, attitude, practice, and self-efficacy pertaining to VA cannulation and evaluation. Binary logistic regression analysis was used to identify predictors of better knowledge of dialysis VA. A total of 197 participants were involved in this study. Around one-third of the study participants (37.0%) reported that they have received specialized training in managing VA. Participants agreement (answered agree or strongly agree) on statements that examined attitudes toward dialysis VA cannulation and management was high and ranged between 75.0% and 93.0%. The majority of participants (97.5%) reported that they perform this assessment. Most nurses (65%) preferred the rope-ladder technique. Participants agreement on statements that examined self-efficacy on dialysis VA cannulation and management was high and ranged between 72.1% and 98.0%. The most commonly agreed upon statement was that "they have confident in performing hemodialysis access (arteriovenous fistula and arteriovenous graft) assessment before cannulation." With 98.0% (answered agree and strongly agree). The mean knowledge score for our study sample was 6.4 (SD: 2.0) out of 12 (53.3%); which reflects marginal-level of knowledge on dialysis VA. Binary logistic regression analysis identified that nurses who have undergraduate degree are 92% more likely to be knowledgeable on dialysis VA compared to others (P < .05). Concerning VA, the level of knowledge among hemodialysis nurses working in Saudi Arabia was inadequate. Nurses who hold an undergraduate degree are presumed to have a more extensive understanding of dialysis VA. Further education programs are necessary for HD nurses to enhance their knowledge of VA, thereby optimizing their professional practices and enhancing the outcomes for their patients.

Feasibility of Breath-Hold Zero TE Magnetic Resonance Imaging Sequence for Evaluation of Pulmonary Arteriovenous Malformations After Embolotherapy

ABSTRACT

We obtained breath-hold zero TE (ZTE) magnetic resonance imaging for the evaluation of pulmonary arteriovenous malformations before and after embolotherapy. To the best of our knowledge, there have been no reports of ZTE for the entire lung imaging in single breath-hold scan time such as 20 seconds. Breath-hold ZTE magnetic resonance imaging can be a useful technique for magnetic resonance-based follow-up of vascular lung diseases without using contrast media, reducing the undesired artifacts from metallic devices.

Effectiveness of a native vein arteriovenous fistula tracking system

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

A Case Report of Modified Pancreatic Transplantation With a Limited Splenic Arteriovenous Fistula to Elude Thrombosis

In classic pancreatic transplantation, the splenic artery and vein are ligated at the tail of the pancreas graft. This leads to slowed blood flow in the splenic vein and may cause thrombosis and graft loss. In this study, a patient received a pancreas after kidney transplantation. A modified surgical technique was used in the pancreatic graft preparation. The donor splenic artery and vein were anastomosed end to end at the tail of the pancreas. The splenic artery near the anastomosis was partially ligated, and an effective diameter of 2 mm was reserved to limit arterial blood pressure and flow. The patient recovered very well. Contrasted computed tomography scans on days 11 and 88 after pancreas transplantation indicated sufficient backflow of the splenic vein. We believe that this procedure may avoid the risk of splenic vein thrombosis after pancreas transplantation. This modified technique has not been reported in clinical cases previously and may help reduce the risk of thrombosis after pancreas transplantation.

Hemodialysis vascular access coordinator: Three-level model for access management

Management of vascular access is a challenge for the dialysis team, particularly to keep the arteriovenous access working. The vascular access coordinator can positively contribute to increase the number of arteriovenous fistulas and reduce central venous catheters. In this article, we introduce a new approach to vascular access management centered on (the results of setting up) the role of vascular access coordinator. We described the three-level model (3Level_M) for vascular access management organized in three levels: vascular access nurse manager, vascular access coordinator, and vascular access consultant. We defined the instrumental skills and training required to be developed by each element and clarify the articulation between the model and all members of the dialysis team related to vascular access.

Use of Polyurethane-Covered Stents for Exclusion of Pulmonary Arteriovenous Malformations

PURPOSE

To evaluate the safety, technical success and short-term effectiveness of polyurethane-covered stent (PK Papyrus, BioTronik, Berlin) in the treatment of pulmonary arteriovenous malformations (PAVMs) that are not amenable to embolotherapy.

MATERIALS AND METHODS

In this IRB-approved, retrospective study, data from patients who received polyurethane-covered stents for exclusion of PAVMs were analyzed. The study included 5 patients (all women) with a median age of 40 years (range 25-60). Patients presented with hypoxemia, TIAs, and/or epistaxis; 4 were confirmed to have HHT. All had multiple PAVMs diagnosed on chest CT and underwent embolization with other devices in addition to the polyurethane-covered stent. The indication for stent placement in all cases was a short and/or tortuous feeding artery. Safety was assessed by immediate or short-term complications, e.g., migration, stent thrombosis, and fracture. Technical success was defined as the ability to accurately place the stent at the intended location. Effectiveness was defined as successful exclusion of PAVM with no perfusion across the AVM.

RESULTS

Technical success of stent placement was 100%. AVM exclusion rate was 80% after single stent deployment; in the case of incomplete exclusion, success was achieved using an overlapping stent to completely cover a second feeding artery. During the median follow-up period of 5 months (range 2-10), all stents remained patent, and AVMs were excluded without other complications.

CONCLUSION

Exclusion of PAVMs with polyurethane-covered stents is technically feasible, safe, and shows short-term effectiveness for PAVMs with a short/tortuous feeding artery when traditional embolization techniques are not possible.

Knowledge of arteriovenous fistula care in patients with end-stage kidney disease in south Asian countries: A systematic review and meta-analysis

OBJECTIVES

To find the prevalence of knowledge of arteriovenous fistula (AVF) self-care, its characteristics, and associated factors among hemodialysis patients and summarize the findings of various domains of AVF self-care in south Asian countries.

METHODS

The systematic literature search was performed on online databases and additional sources to retrieve published articles on AVF self-care. We estimated the pooled prevalence using a random effects model in meta-analysis. Additionally, thematic knowledge regarding various aspects of AVF self-care was narratively summarized.

RESULTS

Among the articles retrieved seven studies met our inclusion and exclusion criteria. The prevalence of AVF self-care in individual studies ranged from 59% to 99%, with an overall random pooled prevalence of 81% (95% CI, 68% to 94%). Major factors associated with self-care of AVF knowledge included patients' educational status, age, vintage of hemodialysis, and healthcare personnel's advice.

DISCUSSION

Knowledge scarcity regarding potential measures of AVF self-care obligates the need for continuous education in hemodialysis patients. A multidisciplinary approach is vital to enhance self-care from pre- to post-creation of AVF in hemodialysis patients as well as their caregivers in order to prolong the patency rates and decrease the subsequent morbidity and mortality due to failure of AVF.

Role of platelet factor 4 in arteriovenous fistula maturation failure: What do we know so far?

The rate of arteriovenous fistula (AVF) maturation failure remains unacceptably high despite continuous efforts on technique improvement and careful pre-surgery planning. In fact, half of all newly created AVFs are unable to be used for hemodialysis (HD) without a salvage procedure. While vascular stenosis in the venous limb of the access is the culprit, the underlying factors leading to vascular narrowing and AVF maturation failure are yet to be determined. We have recently demonstrated that AVF non-maturation is associated with post-operative medial fibrosis and fibrotic stenosis, and post-operative intimal hyperplasia (IH) exacerbates the situation. Multiple pathological processes and signaling pathways are underlying the stenotic remodeling of the AVF. Our group has recently indicated that a pro-inflammatory cytokine platelet factor 4 (PF4/CXCL4) is upregulated in veins that fail to mature after AVF creation. Platelet factor 4 is a fibrosis marker and can be detected in vascular stenosis tissue, suggesting that it may contribute to AVF maturation failure through stimulation of fibrosis and development of fibrotic stenosis. Here, we present an overview of the how PF4-mediated fibrosis determines AVF maturation failure.

Impacts of continuous quality improvement on wound pain in the puncture site of arteriovenous fistula in haemodialysis patient

This study analyses the effects of a continuous quality improvement nursing model on wound pain at the arteriovenous fistula (AVF) puncture site in patients undergoing haemodialysis. Forty haemodialysis patients from the First Affiliated Hospital of Chongqing Medical University, from September 2020 to December 2022, were selected as study subjects. They were randomly divided into an observation group and a control group. The control group received conventional nursing care, while the observation group was treated with a continuous quality improvement nursing model. The study compared the impact of these nursing approaches on pain intensity post-AVF puncture, wound visual analogue scale scores, self-rating anxiety scale, self-rating depression scale, quality of life scores and patient satisfaction with nursing care. In the observation group, the proportion of patients experiencing moderate to severe pain during AVF puncture was lower than that in the control group, whereas the proportion of patients with no pain or mild pain was higher (P = 0.008). After nursing, the observation group exhibited significantly lower wound visual analogue scale scores, self-rating anxiety scale scores, and self-rating depression scale scores compared to the control group (P < 0.001), with a significantly higher quality of life score (P < 0.05). The nursing satisfaction rate was 95.00% in the observation group, significantly higher than the 65.00% in the control group (P = 0.018). The continuous quality improvement nursing model significantly reduces wound pain at the AVF puncture site in haemodialysis patients, alleviates negative emotions, enhances the quality of life, and achieves high patient satisfaction. It is thus a highly recommendable approach in nursing practice.

Clinical features, treatment strategies and outcomes of craniocervical junction arteriovenous fistulas: a cohort study of 193 patients

BACKGROUND

Craniocervical junction (CCJ) arteriovenous fistulas (AVFs) are rare. The current treatment strategies for AVFs with different angioarchitecture need to be clarified. The present study aimed to analyse the correlation between angioarchitecture and clinical characteristics, share our experience in treating this disease and identify risk factors associated with subarachnoid haemorrhage (SAH) and poor outcomes.

METHODS

A total of 198 consecutive patients with CCJ AVFs from our neurosurgical centre were retrospectively reviewed. The patients were grouped according to their clinical manifestations, and their baseline clinical characteristics, angioarchitecture, treatment strategies and outcomes were summarised.

RESULTS

The patients' median age was 56 years (IQR 47-62 years). The majority of patients were men with 166 (83.8%) patients. The most common clinical manifestation was SAH (52.0%), followed by venous hypertensive myelopathy (VHM) (45.5%). The most common CCJ AVFs type was dural AVF, with 132 (63.5%) fistulas. The most frequent fistula location was C-1 (68.7%) and dural branch of vertebral artery (70.2%) was the most involved arterial feeders for fistulas. The most common direction of venous drainage was descending intradural drainage (40.9%), followed by ascending intradural drainage (36.5%). Microsurgery was the most common treatment strategy applied for 151 (76.3%) patients, 15 (7.6%) patients were treated with interventional embolisation only, and 27 (13.6%) received both interventional embolisation and microsurgical treatment. The learning curve for microsurgery only was analysed by cumulative summation method, and the turning point was the 70th case, and blood loss in post-group was lower than that in pre-group (p=0.034). At the last follow-up, there were 155 (78.3%) patients with favourable outcomes (modified Rankin Scale(mRS)<3). Age≥56 (OR 2.038, 95% CI 1.039 to 3.998, p=0.038), VHM as the clinical manifestation (OR 4.102, 95% CI 2.108 to 7.982, p<0.001) and pretreatment mRS≥3 (OR 3.127, 95% CI 1.617 to 6.047, p<0.001) were significantly associated with poor outcomes.

CONCLUSION

The arterial feeders and direction of the venous drainage were important factors in the clinical presentations. The location of fistula and drainage vein was essential for choosing different treatment strategies. Older age, VHM onset and poor pretreatment functional status predicted poor outcomes.

Interventions for thrombosed haemodialysis arteriovenous fistulas and grafts

BACKGROUND

Patients who present with problems with definitive dialysis access (arteriovenous fistula (AVF) or arteriovenous graft (AVG)) become catheter dependent (temporary access), a condition that often carries a higher risk of infections, central venous occlusions and recurrent hospitalisations. For AVG, primary patency rates are reported to be 30% to 90% in patients undergoing thrombectomy or thrombolysis. According to the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) guidelines, surgery is preferred when the cause of the thrombosis is a stenosis at the site of the anastomosis in thrombosed AVF. The European Best Practice Guidelines (EBPG) reported that thrombosed AVF may be preferably treated with endovascular techniques, but when the cause of thrombosis is in the anastomosis, surgery provides better results with re-anastomosis. Therefore, there is a need to carry out a systematic review to determine the effectiveness and safety of the intervention for thrombosed fistulae.

OBJECTIVES

This review aims to establish the efficacy and safety of interventions for failed AVF and AVG in patients receiving haemodialysis (HD).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 28 January 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Portal (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

The review included randomised controlled trials (RCTs) and quasi-RCTs in people undergoing HD treatment using AVF or AVG presenting with clinical or haemodynamic evidence of thrombosis. Patients had to have used an AVF or AVG at least once.

DATA COLLECTION AND ANALYSIS

Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Our search strategy identified 14 eligible studies (1176 randomised participants) for inclusion in this review. We included three types of interventions for the treatment of thrombosed AVF and AVG: (1) types of thrombectomy, (2) types of thrombolysis and (3) surgical procedures. Most of the included studies had a high risk of bias due to a poor study design, a low number of patients and industry involvement. Overall, there was insufficient evidence to suggest that a specific intervention was better than another for the outcomes of failure, primary patency at 30 days, technical success and adverse events (both major and minor). Primary patency at 30 days may improve with surgical compared to mechanical thrombectomy (3 studies, 404 participants: RR 1.36, 95% CI 1.07 to 1.67); however, the evidence is very uncertain. Death, access dysfunction, successful dialysis, and SONG (Standards Outcomes in Nephrology) outcomes were rarely reported. The current review is limited by the small number of available studies with a limited number of patients enrolled. Most of the studies included in this review have a high risk of bias and a low or very low certainty of evidence. Further research is required to define the most effective and clinically appropriate technique for access dysfunction.

AUTHORS' CONCLUSIONS

It remains unclear whether any intervention therapy affects the patency at 30 days or failure in any thrombosed HD AV access (very low certainty of evidence). Future research will very likely change the evidence base. Based on the importance of HD access to these patients, future studies of these interventions among people receiving HD should be a priority.

The chief culprit of intractable hypoxemia: a case report of rare pulmonary arteriovenous fistula complicated with giant hemangioma

BACKGROUND

Pulmonary arteriovenous fistula (PAVF) is a rare disease, which can lead to the direct return of unoxidized venous blood to pulmonary veins and left heart, resulting in right-to-left shunt leading to hypoxia. Long term, the right-to-left shunt will cause severe pathophysiological changes in the patient's body and pulmonary circulation, and the prognosis will be poor if PAVF is not treated timely.

CASE PRESENTATION

Here, we report the case of a 71-year-old man who presented with chest tightness and shortness of breath. After a series of examinations, PAVF and giant hemangioma were diagnosed, which are difficult to operate.Transcatheter interventional therapy was initiated. The patient recovered on the third day after operation and was discharged smoothly. During the long-term follow-up of nearly 4 years after discharge, the general condition and quality of life of the patient basically returned to normal.

CONCLUSIONS

PAVF is rare but very important clinical problem. When the clinical manifestations of persistent unexplained hypoxia appear, it is necessary to fully consider the possibility of PAVF. Once the diagnosis of PAVF is clear, timely treatment is recommended to avoid deterioration of the disease and affecting the prognosis.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cost-effectiveness analysis of endovascular vs surgical arteriovenous fistula creation in the United States

OBJECTIVE

In the United States, an estimated $2.8 billion annually is spent on vascular access and its complications. Endovascular arteriovenous fistula (endoAVF) creation is a novel, minimally invasive alternative to traditional surgical AV fistula (sAVF) creation in ≤60% of patients. Although cost effective in single-payer systems, the clinical and financial impact of endoAVF in the United States remains uncertain.

METHODS

We constructed a decision tree followed by a probabilistic cohort state-transition model to study the cost effectiveness of endoAVF vs sAVF creation. We conducted a systematic review to obtain input parameters including technical success, maturation, patency, and utility values. We derived costs from the Medicare 2022 fee schedule and from the literature. We used a 5-year time horizon, an annual discount rate of 3% for costs and utilities (measured in quality-adjusted life-years [QALYs]), and the common willingness-to-pay threshold of $50,000. One-way and Monte Carlo probabilistic sensitivity analyses were performed varying technical success, patency, reintervention, cost, and utility parameters.

RESULTS

In the base-case scenario, endoAVF ($30,129 average per-person costs, 2.19 QALYs gained, 65% patent at 5 years) was not cost effective compared with sAVF ($12.987 average per-person costs, 2.11 QALYs gained, 66% patent at 5 years), generating an incremental cost-effectiveness ratio of $227,504 per QALY gained. In one-way sensitivity analyses, endoAVF becomes cost effective when the initial cost of sAVF creation exceeds endoAVF by ≥$600 (eg, if endoAVF creation costs ≤$3000 relative to the base-case sAVF cost of $3600), the additional QALYs gained from endoAVF exceeds 0.12 QALYs/year (eg, 0.81 QALYs gained/year from endoAVF compared with base-case sAVF 0.69 QALYs/year), the endoAVF maturation rate is >90% (base case 78%), or the sAVF maturation rate is <65% (base case 78%). Probabilistic sensitivity analysis demonstrated that sAVF remained the optimal strategy in 71% of iterations.

CONCLUSIONS

EndoAVF is not cost effective compared with sAVF when modeling 5-year outcomes. The main driver of sAVF remaining cost effective is the four times higher up-front cost for endoAVF creation, as well as a relatively low additional increase in quality of life for endoAVF. It will be important to establish how the endoAVF learning curve contributes to upfront costs and, given the annual cost attributed to vascular access nationally, a randomized controlled trial is warranted.

Effectiveness of the Eutectic Mixture of Local Anaesthetics Cream in the Management of Arteriovenous Fistula Needle Insertion Pain in Patients Undergoing Haemodialysis

This review aimed to assess the effectiveness of the eutectic mixture of local anaesthetics (EMLA) cream in the management of arteriovenous fistula (AVF) needle insertion pain in adult patients undergoing haemodialysis (HD) compared with other alternative interventions. The main search was conducted in November 2020 and updated in December 2021. In the search strategy, keywords and synonyms were used and multiple databases were searched with no date limitation to ensure a comprehensive search that would yield all studies relevant to the review and minimise location bias. A total of 209 studies were found in this search and filtered. After filtering through these studies, only five studies were finally included in the review. EMLA-cream was found to be effective in reducing AVF needle insertion pain among adult patients undergoing HD. Despite EMLA cream's effectiveness in reducing HD needle insertion pain and its fewer side effects, the findings of the included studies should be interpreted with caution, as there are some limitations, and further research is required.

Factors Affecting the Early Maturation of Arteriovenous Fistulae Created at a Tertiary Centre in Oman

Objectives

This study aimed to determine the risk factors associated with the failure of arteriovenous fistulae (AVF) maturation.

Methods

This retrospective cohort study was conducted from January 2014 to December 2018 in Sultan Qaboos University Hospital, Muscat, Oman. Patients were followed-up 3 months after surgery, and their electronic medical records were accessed for demographic and clinical data. Univariate analysis was used to determine the risk factors associated with early AVF maturation and multivariant analysis was used to determine the predictive factors for AVF failure.

Results

A total of 269 patients were included. Female gender was a significant factor affecting AVF maturity (P = 0.049), while age (P = 0.626), diabetes (P = 0.954), hypertension (P = 0.378), dyslipidaemia (P = 0.907), coronary artery disease (P = 0.576), cerebrovascular accident (P = 0.864), congestive heart failure (P = 0.685), previous central venous catheterisation (P = 0.05), fistula type (P = 0.863) and fistula site (P = 0.861) did not affect AVF maturation. Binary logistic regression showed that all the risk factors were insignificant. Failure of early AVF maturation affected 11.5% in the cohort.

Conclusion

This study found that the proportion of early AVF maturation at our hospital is at par with that in the international literature. Failure of AVF maturation was significantly associated with the female gender. These findings can help nephrologists and vascular surgeons prognosticate AVF maturation rates. However, a larger study is needed for definitive conclusions.

What are the observed procedural costs of vascular access surgery? Protocol for a systematic review

INTRODUCTION

A central component in the introduction of a novel surgical procedure or technique is an evaluation of its cost efficiency when compared with a benchmark standard of care. Accurate assessment of costs is thus essential in ensuring appropriate allocation of resources within a healthcare system. The treatment of kidney failure requires a significant volume of resources, and vascular access provision is the main modifiable cost. The costs of providing this service are obscured by generic NHS reference costs, which lack adequate granularity to allow meaningful comparisons between treatments. The aim of this systematic review will be to assess the reporting of procedural costs in all published economic analyses of vascular access surgery and perform a comparison of the reported procedural costs involved in arteriovenous fistula (AVF) and arteriovenous graft (AVG) creation. This will provide an estimate as to the accuracy of the NHS reference costs in this field.

METHODS AND ANALYSIS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will be followed. A systematic search will be performed of the MEDLINE, Embase and Cochrane databases to identify full-text economic analyses of vascular access for haemodialysis in which the procedural cost of AVF or AVG creation is reported. Publications in English from 1 January 2000 to 30 August 2023, will be eligible for inclusion. Studies will be selected by title and abstract review, followed by a full-text review using inclusion and exclusion criteria. Studies not reporting the procedural costs of surgery will be excluded. Data collected will pertain to procedural costs of AVF and AVG creation. Costs will be adjusted to a common currency using a gross domestic product (GDP) deflator index and conversion rates based on purchasing power parities for GDP. Comparison with NHS reference costs will indicate their reliability for use in future economic analyses in this field.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review. Findings will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42023458779.

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.

Combined endovascular and percutaneous approach to the management of spontaneous splenic arteriovenous fistula

A splenic arteriovenous fistula (AVF) is an uncommon splenic vascular disease which can be congenital or acquired. A 40yr old woman, without any history of chronic liver disease, presented with non-specific pain abdomen, underwent contrast-enhanced CT and was diagnosed to have a splenic AVF with multiple intervening venous aneurysms and early filling of the portal vein. The vascular abnormality was successfully treated with a combined percutaneous glue embolisation and endovascular balloon-assisted coil embolisation. Neither recurrence nor other complications were observed in the patient during the follow-up after 6 months.

Comparative analysis of RADAR vs. conventional techniques for AVF maturation in patients with blood viscosity and vessel elasticity-related diseases through fluid-structure interaction modeling: Anemia, hypertension, and diabetes

PURPOSE

This study aims to compare two surgical techniques, the standard Vein-to-Artery and the newer Artery-to-Vein (Radial Artery Deviation And Reimplantation; RADAR), for enhancing the success of Arterio-Venous Fistula maturation in end-stage renal disease patients. The impact of diseases like anemia, diabetes, hypertension, and chronic kidney disease were considered. The goals are to advance Arterio-Venous Fistula (AVF) surgery, improve patient outcomes, and contribute to evidence-based surgical guidelines.

METHODS

Fluid-structure interaction modeling was employed to investigate how hemodynamic and mechanical stresses impact arteriovenous fistula maturation, with a particular focus on the role of wall shear stress in determining maturation outcomes. The critical threshold for vessel injury was identified as wall shear stress values exceeding 35 N/m2, while stenosis formation was projected to occur at levels below 1 N/m2. This work introduced a novel approach by considering disease-related factors, including blood viscosity (anemia), and vessel elasticity (diabetes, hypertension, and chronic kidney diseases), which directly influence hemodynamics and the generation of wall shear stress. Furthermore, the model was designed to incorporate varying thicknesses and elasticities for both the vein and artery, accurately representing authentic vascular anatomy.

RESULTS

The RADAR technique has demonstrated superior performance compared to the standard technique by providing appropriate wall shear stress in critical regions and minimizing the risk of wall damage. Its use of a thicker vessel also reduces the risk of vessel injury, making it particularly effective for patients with Chronic Kidney Disease (CKD), hypertension, anemia, and diabetes, ensuring optimal blood flow and fewer complications. However, there are minor concerns about stenosis formation in hypertension and anemia cases, which could be mitigated by adjusting the anastomosis angle to be lower than 30°.

CONCLUSION

Diabetes and hypertension have significant physiological effects that increase the risks associated with arteriovenous fistula maturation. The anemic condition resulting from CKD may help reduce vessel injury but raises concerns about potential stenosis formation. Despite these co-morbidities, the RADAR technique has demonstrated its ability to induce more favorable hemodynamic changes, promoting arteriovenous fistula maturation.

A comparison of arteriovenous fistula failure between Malaysian and Australian and New Zealand participants enrolled in the FAVOURED trial

AIM

To describe and compare de novo arteriovenous fistula (AVF) failure rates between Australia and New Zealand (ANZ), and Malaysia.

BACKGROUND

AVFs are preferred for haemodialysis access but are limited by high rates of early failure.

METHODS

A post hoc analysis of 353 participants from ANZ and Malaysia included in the FAVOURED randomised-controlled trial undergoing de novo AVF surgery was performed. Composite AVF failure (thrombosis, abandonment, cannulation failure) and its individual components were compared between ANZ (n = 209) and Malaysian (n = 144) participants using logistic regression adjusted for patient- and potentially modifiable clinical factors.

RESULTS

Participants' mean age was 55 ± 14.3 years and 64% were male. Compared with ANZ participants, Malaysian participants were younger with lower body mass index, higher prevalence of diabetes mellitus and lower prevalence of cardiovascular disease. AVF failure was less frequent in the Malaysian cohort (38% vs 54%; adjusted odds ratio (OR) 0.53, 95% confidence interval (CI) 0.31-0.93). This difference was driven by lower odds of cannulation failure (29% vs 47%, OR 0.45, 95% CI 0.25-0.80), while the odds of AVF thrombosis (17% vs 20%, OR 1.24, 95% CI 0.62-2.48) and abandonment (25% vs 23%, OR 1.17, 95% CI 0.62-2.16) were similar.

CONCLUSIONS

The risk of AVF failure was significantly lower in Malaysia compared to ANZ and driven by a lower risk of cannulation failure. Differences in practice patterns, including patient selection, surgical techniques, anaesthesia or cannulation techniques may account for regional outcome differences and warrant further investigation.

The role of vacuum-assisted mechanical thrombectomy in the management of acutely thrombosed arteriovenous fistulas and grafts

PURPOSE

The purpose of this study is to evaluate the safety and efficacy of the mechanical thrombectomy with the Indigo System in the treatment of thrombosed arteriovenous fistulas and grafts.

METHODS

A retrospective search of endovascular procedures performed from November 2018 to June 2020 was conducted. Inclusion criteria were: acute arteriovenous fistula or graft thrombosis that underwent endovascular mechanical thrombectomy with Indigo System. The following information was collected from each case: sex, age, fistula modality, fistula location, treatment modality, and outcomes. Endpoints evaluated were: technical and clinical success rates; primary, assisted primary, and secondary patency rates; complication rates.

RESULTS

Twenty-six mechanical thrombectomy procedures for declotting of arteriovenous fistula thrombosis, using the Indigo System, were performed in 22 patients. Technical and clinical success was achieved in 23/26 cases (88%). Mean follow-up was 9 months (range 11-539 days). The 6-month primary, primary assisted, and secondary patency rates were 71%, 86%, 93% and the 12-month primary, primary assisted, and secondary patency rates were 71%, 72%, 80%, respectively. No technical or device-related complications were observed during thrombectomy, however two venous ruptures occurred on the angioplasty of the underlying stenosis.

CONCLUSION

In conclusion, vacuum-assisted thrombectomy of acutely thrombosed arteriovenous fistulas and grafts with Indigo System is safe and effective, providing good short term patency rates.

Arteriovenous fistula creation with VasQTM device: A feasibility study to reveal hemodynamic implications

BACKGROUND

Arteriovenous fistula (AVF) is the preferred vascular access (VA) for hemodialysis, but it is still affected by high non-maturation and early failure rates due to stenosis development. Increasing evidence suggests that the presence of turbulent-like flow may play a key role, therefore, to stabilize the flow in the venous segment, an external support device (VasQTM) has been designed. The aim of this study was to provide preliminary evidence of VasQTM impact on AVF hemodynamics as compared to AVFs created with conventional surgery.

METHODS

In this pilot single-center prospective randomized study six patients were enrolled, three in the VasQ group and three in the control group. Contrast-free magnetic resonance imaging (MRI) scans were acquired at 3 days, 3 months and 1 year after AVF surgery and were used to generate 3D patient-specific models. Computational fluid dynamic (CFD) simulations were performed using pimpleFoam, imposing patient-specific flow waveforms derived from ultrasound (US) examinations at the inlet of the proximal and distal artery, and a traction-free condition at the venous outflow. Morphologic and hemodynamic changes occurring over time were compared between VasQ and control AVFs.

RESULTS

Our MRI protocol provided high-quality images suitable for reliable segmentation and reconstruction of patient-specific 3D models of AVFs at all three timepoints in four out of six patients. The VasQTM device maintained the angle between the artery and the vein almost unchanged over time, with a more stable flow in the AVFs supported by the device. In contrast, one of the AVFs of the control group evolved to an extreme dilatation of the vein and highly disturbed flow, while the other developed a stenosis in the juxta-anastomotic region.

CONCLUSIONS

This study demonstrated the feasibility of characterizing the morphological and hemodynamic changes occurring over time in AVFs created using the VasQTM device and provided preliminary evidence of the potential hemodynamic benefits of its use.

Successful 8-year use of Venous Window Needle Guide for deep arteriovenous fistula cannulation

We describe the case of a patient who had been on hemodialysis for 8 years using a native arteriovenous fistula cannulated through the Venous Window Needle Guide™ device (VWING). The overall outcome was excellent and complication-free with intact state of the underlying vessel and a high degree of patient satisfaction. The patient was able to carry out self-cannulation without any difficulty almost from the very beginning. The current unavailability of VWING is a missed opportunity in the field of vascular access.

Strategies to Mitigate Bleeding in Shoulder Arthroplasty in the Setting of an Arteriovenous Fistula: A Report of 3 Cases

CASE

Arteriovenous (AV) fistula in the ipsilateral extremity for hemodialysis presents unique challenges during shoulder arthroplasty. We describe 3 cases of shoulder arthroplasty performed through a deltopectoral approach on the ipsilateral side of an AV fistula. In all cases, the cephalic vein was found to be arterialized with increased diameter and thickness. All procedures were successfully performed without injury to the arterialized cephalic vein.

CONCLUSION

This report highlighted strategies to mitigate catastrophic bleeding from an arterialized cephalic vein during shoulder arthroplasty, which includes preoperative cross-matching, expeditious vascular surgery availability, meticulous surgical dissection, and careful retractor placement.

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

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

Exercise guide to help on arteriovenous fistula maturation and maintenance

BACKGROUND

The arteriovenous fistula is the main vascular access in hemodialysis. Arteriovenous fistula access is generally evaluated by a vascular surgeon after 2 weeks of its surgery, however, exercise programs may begin earlier for improving outcomes. Therefore, we propose this guide with simple, but potentially effective exercises, using low-cost materials that can be safely performed by the patients at home or in the dialysis center. It also provides to the dialysis staff team a starting point for implementing an upper-limb exercise program that may facilitate arteriovenous fistula maturation and maintenance.

METHODS

This exercise routine for arteriovenous fistula maturation can be performed three to four times a day, every day, from 2 to 4 weeks. After its maturation, it can be performed on every non-dialysis day for conventional treatment and every other day, before dialysis, for short daily treatment.

CONCLUSIONS

Based on the available evidence, we have gathered some exercises, in a very easy and understandable language, that may potentially help arteriovenous fistula maturation and maintenance for hemodialysis patients.

Effects of endothelial nitric oxide synthase on mouse arteriovenous fistula hemodynamics

Newly created arteriovenous fistulas (AVFs) often fail to mature for dialysis use due to disturbed blood flow at and near the AVF anastomosis. The disturbed flow inhibits the endothelial nitric oxide synthase (NOS3) pathway, thus decreasing the production of nitric oxide, a vasodilator. Previously, our group reported that NOS3 expression levels affect AVF lumen size in a mouse model. In this study, we performed MRI-based computational fluid dynamics simulations to investigate the hemodynamical parameters (velocity, wall shear stress (WSS), and vorticity) in a mouse AVF model at day 7 and day 21 post-AVF creation using three NOS3 strains: overexpression (OE), knockout (KO), and wild-type (WT) control. This study is the first to reveal hemodynamics over time in mouse AVFs, consider spatial heterogeneity along the vein, and reveal the effect of NOS3 on the natural history of mouse AVF hemodynamics. From day 7 to day 21, OE has smoother streamlines and had significantly lower vorticity and WSS than WT and KO, suggesting that WSS was attempting to return to pre-surgery baseline, respectively. Our results conclude that the overexpression of NOS3 leads to desired optimal hemodynamics during AVF remodeling. Future studies can investigate enhancing the NOS3 pathway to improve AVF development.

The reasons for comparative effectiveness clinical trials of arteriovenous fistula versus graft strategy in older adults on hemodialysis with a catheter

Clinicians and patients are guided by observational studies to make one of the most consequential decisions for patients with advanced kidney disease: the selection of the "right" hemodialysis vascular access. More than a decade ago, a call for randomized clinical trials was made to equitably compare clinical outcomes between arteriovenous (AV) fistulas (AVFs) and AV grafts (AVGs). Mounting evidence suggests that trade-offs between AVF- and AVGrelated outcomes are context dependent. In this article, we summarize four streams of evidence that collectively underpin the burden of equipoise between the two types of AV access in older adults with comorbidities who are on hemodialysis with a central venous catheter.

Inflow Artery Aneurysmal Degeneration After Long Term Native Arteriovenous Fistula for Haemodialysis

OBJECTIVE

Inflow arterial aneurysms are a rare but serious complication after long term arteriovenous fistulae (AVF), probably due to arterial wall remodelling after an increase in flow and shear stress, and kidney transplantation with immunosuppressive therapy. This study aimed to describe the outcomes of surgical treatment and long term follow up in a large cohort.

METHODS

This prospective cohort study collected data from patients with a true inflow artery aneurysm after AVF creation that was surgically repaired between 2010 and 2022. Anastomotic and infected aneurysms or post-puncture pseudoaneurysms were excluded. Demographic data, access characteristics, symptoms, treatment strategies, and long term follow up were recorded; patency was estimated using Kaplan-Meier survival analysis.

RESULTS

During the study period, 28 patients (64% men, mean age 60.1 years) were treated surgically for aneurysmal degeneration of the axillary or brachial (n = 23) or radial (n = 5) artery after an AVF (10 distal, 18 proximal) performed a mean of 18.3 ± SD 7.9 years previously. Most AVFs were ligated or thrombosed, while all patients except one had previously received kidney transplants. Most of the cases (n = 18) were symptomatic: 13 with pain or swelling, four with distal embolisation, and one rupture. They were repaired by aneurysm partial excision and graft interposition (11 great saphenous vein, six ipsilateral basilic vein, three cephalic vein, and two PTFE graft), ligation (n = 3), or direct end to end anastomosis (n = 3). No major complications occurred before discharge, after a mean hospital stay of 2.4 days. After a mean follow up of 4.8 ± 3.3 years, three cases presented complications: two recurrent proximal brachial aneurysms were repaired with an additional proximal interposition graft (one with further late infected pseudoaneurysm) and an asymptomatic post-traumatic graft thrombosis. Five year primary and secondary patency was 84% and 96%, respectively.

CONCLUSION

Aneurysmal degeneration of the inflow artery is an unusual complication during long term follow up of AVFs. Aneurysm excision and, in general, autogenous graft interposition using the saphenous or ipsilateral arm vein is a safe and effective strategy.

Transvenous Embolization of Dural Arteriovenous Fistulas Through the Galenic (Deep Venous) System: Multicenter Case Series and Meta-Analysis

BACKGROUND AND OBJECTIVES

Arteriovenous fistulas involving the deep venous system have often been treated with microsurgery or transarterial embolization. Increasing familiarity with transvenous navigation and improved endovascular access systems may facilitate transvenous embolization (TVE) for these rare and challenging lesions.

METHODS

We performed a retrospective study of neurointerventional databases of 6 high-volume centers. We identified all cases of arteriovenous fistulas with deep transvenous embolizations for arteriovenous fistula. Details regarding demographics, fistula characteristics, treatment considerations, clinical outcomes, and fistula occlusion were obtained and analyzed. The meta-analysis used the same inclusion criteria.

RESULTS

Seventeen cases of TVE were identified. The most common reasons for TVE included prior treatment failure with microsurgery (n = 2) or transarterial embolization (n = 3) or inaccessible arterial pedicles (n = 4). For patients with full clinical outcome data (n = 14), 2 patients had worsened modified Rankin Scale, 8 patients had no change, and 4 were improved at a median clinical follow-up of 3.5 months. Angiographic obliteration was achieved in 15/17 cases (88.2%). In 1 case, catheterization around a sharp turn in the basal vein of Rosenthal could not be performed. In another case, despite successful TVE, there was residual lesion which was treated 1 year later by microsurgical clipping and excision.

CONCLUSION

Transvenous approaches for embolization of deep arteriovenous fistulas have become possible with modern endovascular catheter systems and liquid embolics. These lesions can be treated safely and effectively through endovascular approaches, which may spare patients the traversal of deep structures needed for microsurgical approaches to these regions. The outcomes of TVE are comparable with published outcomes of microsurgical interruption.

Juan Bi Tang, a traditional Chinese medicine, for alleviating pain related to arteriovenous fistula in maintenance hemodialysis patients: An interventional pilot study with brief review

Myofascial pain around an arteriovenous fistula (AVF) during hemodialysis (HD) can affect a patient compliance with HD and quality of life. Prolonged use of analgesics is often associated with increased adverse events. Juan Bi Tang (JBT) is an ancient decoction of Chinese traditional medicinal plants commonly used to treat spasms and pain in the shoulder and upper arm, and it is popularly believed to have favorable outcomes in Asian populations. This interventional prospective pilot study was worked to demonstrate the potential of JBT for fistula-associated myofascial pain in HD patients and to prepare for future randomized controlled trials. Eligible patients were enrolled in this study and took JBT to treat fistula-associated myofascial pain for 4 weeks. Pain scores on a visual analogue scale (VAS) were reported at baseline, after a 4-week intervention, and 2 weeks after completion of treatment. The Kidney Disease Quality of Life 36-Item Short Form and a safety laboratory monitor were statistically compared between different time points. A total of 20 patients were selected as eligible participants and completed the intervention and questionnaires. The mean VAS score was significantly reduced after JBT treatment (P < .01). Participants reported improved physical (P < .01) and mental health (P < .05) after treatment. However, only improvements in mental health were preserved 2 weeks after the end of treatment (P < .05). In this study, complementary JBT for HD patients with fistula-related myofascial pain was viable and well tolerated, and it demonstrated the expected effects on pain control.

Perineural low dexamethasone dose as adjuvant in supraclavicular brachial plexus block for arteriovenous fistula creation in end stage renal disease: a randomized controlled trial

BACKGROUND AND AIMS

Dexamethasone as adjunct to local anesthetic solution improves the quality of brachial plexus block (BPB). However, evidence for its efficacy at low doses (< 4 mg) is lacking. This study was designed to evaluate the duration of analgesia attained with low dose dexamethasone as adjuvant to local anesthetic for creation of arteriovenous fistula (AVF) under BPB.

METHODS

Sixty-six patients scheduled for AVF creation were randomly allocated to receive either saline (control) or 2 mg dexamethasone, together with 0.5% ropivacaine and 0.2% lignocaine. The primary outcome was duration of analgesia, defined as time from performing the block to the first analgesic request. The secondary outcomes were time from injection to complete sensory block, time from injection to complete motor block, duration of motor block, postoperative analgesic consumption, and fistula patency at three months.

RESULTS

All the blocks were effective. In the group that received dexamethasone, the time to first analgesic request was significantly delayed (432 ± 43.8 minutes vs. 386.4 ± 40.2 minutes; p < 0.01). The onset of sensory and motor blockade occurred faster in dexamethasone group and overall analgesic consumption was also reduced. However, dexamethasone addition did not prolong the duration of motor block. There was no statistically significant difference in the patency of fistulas between the two groups at three months. (p = 0.34).

CONCLUSION

Addition of low-dose perineural dexamethasone to local anesthetic solution significantly prolonged the duration of analgesia. Further trials are warranted to compare the adverse effects between dexamethasone doses of 4 mg and lower.

Salvage of infected autogenous arteriovenous fistulas, is it possible?

BACKGROUND

Infection in autogenous arteriovenous fistulas (AVFs) is a critical situation in patients with end stage renal disease (ESRD) that can lead to life threatening rupture or septicemia. To date, no standard guidelines regarding the surgical repair of the infected AVFs is available.

AIM

To evaluate the safety and efficacy of the surgical repair in the infected autogenous AVFs.

METHODS

This prospective study involved 64 ESRD patients who presented with infected autogenous AVFs. Repair of the infected autogenous AVFs was done in 50 cases, while ligation was needed in the other 14 cases. Aneurysmorrhaphy was done in the 26 cases of puncture site infection over venous aneurysms. In 20 cases of AVFs with anastomotic disruption, higher recreation in a proximal clean field (AVF loop anastomosis) was performed, while abscess drainage was done in the remaining four cases presented with non-communicating abscess over the vein. The 14 cases of ligated AVFs included 9 cases of infected ruptured AVFs with active bleeding and 4 cases with non-reconstructable puncture site infection.

RESULTS

After 1 year of follow up, 41 cases (82%) of the repaired AVFs (n = 50) remained patent and functioning as re-infection occurred in 9 cases. Six tunneled permanent catheters were implanted in the 14 cases with ligated AVFs, while the remaining 8 cases had new AVFs established (7 cases of them retained patent AVFs during the follow up period).

CONCLUSION

Surgical repair of the infected AVFs is an effective procedure that achieves many goals, such as saving patients' lives, maintaining the patency of the native fistula, and avoidance of creation of new AVFs in another site with exhaustion the available veins.

Comparison of wound complications between one-stage and two-stage brachiobasilic arteriovenous fistula: A meta-analysis

Research assessing the outcome of brachiobasilic arteriovenous fistulas (BB-AVF) after a one- and two-stage technique was conducted. A strict review of the comprehensive literature up to May 2023 was carried out using four databases-PubMed，Embase, Cochrane Library and web of science. Inclusion and exclusion criteria developed for the study were then applied to assess the quality of the literature, it was decided to review 12 interrelated studies.95% confidence intervals (Cl) and odds ratios (OR) were calculated using fixed effects models. The data were meta-analysed using RevMan 5.3 software. The results showed that two-stage technique with BB-AVF reduced surgical site haematoma (SSH) formation, (OR, 2.28; 95% CI, 1.24-4.17, p = 0.008), and also reduced surgical site wound infection (SSWI) (OR, 1.86; 95% CI, 1.17-2.94, p = 0.008). There are, however, several small sample sizes in the selected studies for this meta-analysis, so caution should be used when processing their values. There are more high-quality studies with large sample sizes that should be considered for future meta-analyses.

Anesthetic effect of ultrasound-guided block of the musculocutaneous nerve during endovascular treatment of dysfunctional radiocephalic arteriovenous fistulas

BACKGROUND

Delivering requisite and minimal anesthesia for endovascular treatment (EVT) of dysfunctional arteriovenous fistulas (AVFs) under the target nerve block can achieve reasonable analgesia. We evaluated the anesthetic efficacy of ultrasound (US)-guided selective block of the musculocutaneous nerve (MCN) during the EVT of runoff venous strictures in the forearm through the radiocephalic (RC)-AVF at the wrist or the anatomical snuff box and analyzed the factors inhibiting the analgesia achieved under the MCN block.

METHODS

We enrolled 30 adult patients undergoing hemodialysis who had received 78 EVT sessions in an outpatient clinic mainly for long and/or multiple outflow-venous strictures in the forearm under US-guided blocks of the MCN, which provides sensory innervation to the anterolateral forearm where the cephalic vein courses. We assessed patients' pain during balloon dilations using the Wong-Baker FACES® Pain Rating Scale (WBFRS) and evaluated the factors increasing the pain (WBFRS score ⩾4), including patient characteristics, dilated strictures, additional nerve blocks, and types of balloon catheters.

RESULTS

In 25 EVT sessions (32.1%) out of 78 sessions, patients complained of stronger pain (WBFRS score ⩾4), while in the other 53 sessions (67.9%), presented with no pain and slight pain (WBFRS score = 0 or 2). Univariate analysis clarified that dilation of the AVF anastomosis, presence of dilated stenosis >4 cm, and a single block of the MCN or its sensory terminal significantly triggered more pain (p < 0.05). Consequently, multivariate analysis of all the factors with p < 0.1 in the univariate analysis, including multiple dilated stenosis sites, demonstrated that dilation of the AVF anastomosis significantly caused severe pain despite the anesthesia of the MCN block (p < 0.05).

CONCLUSION

US-guided selective block of the MCN could be a leading anesthetic option for EVT for multiple long stenoses of the cephalic vein draining through the RC-AVF in the wrist or anatomical snuff box.

Automated 3D ultrasound enables novice users to measure arteriovenous fistula maturation parameters with comparable accuracy to conventional duplex by trained sonographers: Results of a benchtop study

BACKGROUND

Arteriovenous fistulae (AVF) are considered the preferred hemodialysis access but up to 50% of all AVF created in the United States never mature. Doppler ultrasound (DUS) is useful for predicting fistula maturity and impending fistula failure. DUS is resource-intensive and is associated with poor compliance rates in dialysis patients, ranging from 12% to 33%.

METHODS

EchoSure is an FDA-cleared 3D Doppler ultrasound device that automatically delivers quantitative blood flow and anatomic vascular information. The technology can be used at the bedside by personnel without formal sonographic training, nullifying limitations of traditional Duplex ultrasound imaging. This study compared the EchoSure system in the hands of inexpert personnel to a traditional expert-operated DUS for rapid assessment of a benchtop model vascular system with flow, diameter, and depth expected in a human AVF.

RESULTS

Both Duplex and EchoSure performed within the expected tolerance of ultrasound readings (35%) for volume flow, with the average error (AE) between the observed measurement and the ground truth being 8% for Duplex and 8% for EchoSure. However, the average coefficient of variation (CV) for Duplex pooled over all flow rate measurements was 17% versus 4% for EchoSure. Regarding diameter, Duplex measurements had AE of 15% with an average CV of 6% across all measurements versus EchoSure AE of 4% and average CV of 2%. Duplex and EchoSure measurements over all depths had the same AE of 2%. The two modalities were not statistically different for depth measurement (p = 0.05) but EchoSure measured closer to the ground truth for flow rate and vessel diameter (flow: p = 0.028, ρ = -0.07; diameter: p < 0.001, ρ = 0.69). The inexpert personnel using EchoSure acquired data 62% faster than the expert sonographers using the Duplex ultrasound (141 min for Duplex vs 87 min for EchoSure).

CONCLUSIONS

EchoSure may offer an accurate and convenient alternative for imaging fistulas in the clinic.

A new hope for vascular access, modifying a new technique: The Surfacer® Inside-Out Access Catheter System and sharp recanalization

Vascular access (VA) for hemodialysis (HD) continues to be the keystone of the technique's success. The first option should be an arteriovenous fistula (AVF) or arteriovenous graft (AVG), although in some scenarios the only possibility available is a central venous catheter, which could lead to an increase in vascular complications such as thoracic central vein occlusion (TCVO), becoming a challenge for physicians. If conventional therapies cannot be performed, a new device called the Surfacer® Inside-Out® Access Catheter System (IOA) (Bluegrass Vascular Technologies, San Antonio, TX, USA) arises as a promising alternative. Here we describe the case of a patient in which we performed a combination of two techniques: sharp recanalization plus Surfacer® Inside-Out® Access Catheter System.

Predictors of Arteriovenous Fistula Maturation among Patients with Severe Obesity

BACKGROUND

There is an increasing prevalence of obesity among patients who develop end-stage renal disease and require dialysis. While referrals for arteriovenous fistulas (AVFs) among patients with class 2-3 obesity (i.e., body mass index [BMI] ≥ 35) are increasing, it is unclear what type of autogenous access is most likely to mature in this patient population. This study was designed to evaluate factors that impact maturation of AVF among patients with class ≥2 obesity.

METHODS

We retrospectively reviewed AVFs created at a single center from 2016 to 2019 for patients who had undergone dialysis within the same healthcare system. Ultrasound studies were used to evaluate factors that defined functional maturation, including diameter, depth, and volume flow rates through the fistula. Logistic regression models were used to evaluate the risk-adjusted association between class ≥2 obesity and functional maturation.

RESULTS

A total of 202 AVFs [radiocephalic (24%), brachiocephalic (43%), and transposed brachiobasilic (33%)] were created during the study period, of which 53 (26%) patients had a BMI >35. Functional maturation was significantly lower among patients with class ≥2 obesity undergoing brachiocephalic (58% obese versus 82% normal-overweight; P = 0.017), but not radiocephalic or brachiobasilic AVFs. This was primarily a result of excessive AVF depth in severely obese patients (9.6 ± 4.0 mm obese versus 6.0 ± 2.7 mm normal-overweight; P < 0.001), whereas there was no significant difference found in average volume flow or AVF diameter between groups. In risk-adjusted models, a BMI ≥35 was associated with a significantly lower likelihood of achieving AVF functional maturation (odds ratio: 0.38; 95% confidence interval: 0.18-0.78; P = 0.009) after controlling for age, sex, socioeconomic status, and fistula type.

CONCLUSIONS

Patients with a BMI >35 are less likely to mature AVFs after creation. This principally affects brachiocephalic AVFs and occurs because of increased fistula depth as opposed to diameter or volume flow parameters. These data can help guide decision-making when planning AVF placement in severely obese patients.

Hybrid Revision of Dysfunctional Aneurysmal Arteriovenous Fistulas

Endovascular therapy has become the first-line treatment for failing hemodialysis arteriovenous fistulas (AVFs). However, open revision remains an important modality for vascular access maintenance and the recommended approach for AVF aneurysms. This case series describes a hybrid approach for aneurysmal access revision. Three patients were referred for second opinion after failure of endovascular therapy to establish a functioning access. The medical history is briefly described to highlight the limitations of endovascular therapy and the technical advantages of the hybrid approach in these clinical scenarios.

A snapshot of early venous remodeling in a 7-day-old arteriovenous fistula

Early remodeling of the arteriovenous fistula (AVF) determines maturation outcomes. However, the cellular response of the venous wall early after AVF creation remains largely enigmatic because of the lack of venous biopsies obtained shortly after anastomosis. This report presents a detailed immunohistochemistry analysis of a pre-access cephalic vein and the resulting seven-day-old AVF that required ligation due to steal syndrome. We test for markers of mature and progenitor endothelial cells (CD31, CD34, VWF), contractile smooth muscle cells and myofibroblasts (MYH11, SMA), and immune cell populations (CEACAM8, CD3, CD20, CD11b, CD45, CD68, CD163, tryptase). We demonstrated near complete endothelial coverage of the fistula at 7 days, a high degree of wall neovascularization, pronounced loss of myofibroblasts and smooth muscle cells, and significant infiltration of mast cells, neutrophils, monocytes, and macrophages. Of interest, the presence of CD163+ macrophages in the AVF suggests a reactive response to increased intramural oxygenation. In conclusion, these images provide for the first time a glimpse of early remodeling in a human AVF by immunohistochemistry. This case demonstrates the possibility to obtain additional precious samples of this early stage through future multicenter collaborative efforts.