Severe Orbital Congestion After a Brow Lift Due to an Osteodural Arteriovenous Fistula

The authors describe a 73-year-old woman who developed worsening proptosis, binocular diplopia, and periorbital pain shortly after undergoing an open subperiosteal brow lift procedure. She was found to have a pre-existing osteodural fistula (ODF) within left frontal bone, which was draining through supraorbital vein (SOV) in cavernous sinus. When SOV was inadvertently severed during a brow lift, blood from the fistula was now redirected in the orbit. This is the first report of a decompensated ODF after a brow lift procedure. It underscores the complexity of orbital venous drainage and the importance in preserving the supraorbital and supratrochlear veins during brow lift.

Dialysis Access Evaluation

The vascular lab (VL) provides vital information for dialysis access to guide management. This article discusses the indication, protocol, and diagnostic criteria for the evaluation of arteriovenous fistulas and grafts. An arteriovenous (AV) dialysis access is made by creating a connection between an artery and vein (AV fistula [AVF]) or by interposing a conduit between an artery and a vein (AV graft [AVG]) to provide high flow circuit for hemodialysis. A normal mature AV dialysis access has a thrill or vibration from turbulent flow in the graft or vein. The nomenclatures at our institution for an AVF and AVG are in the Figure 1 A and B diagrams.

[Contribution of hemostatic dressings in the hemostasis of arteriovenous fistula? A quality improvement program in our center]

INTRODUCTION

In haemodialysis patients the length of bleeding times after fistula cannulation is an easy and fairly used method of monitoring vascular access. In the most cases, compression is performed manually by nurses and the use of haemostatic dressing is common. As data in the literature are scares, we have decided to develop a quality improvement program in our hemodialysis center to manage this issue.

MATERIAL AND METHODS

After informed consent, 35 hemodialysis outpatients were selected in order to study the bleeding time using haemostatic dressing or not during two weeks in a cross over schema. The dialysis schedule was unchanged and comparative analysis of parameters such as blood flow rate or anticoagulant treatment were done between the groups.

RESULTS

Compression times with and without hemostatic dressing were not different (12.6 min and 12.9 min, respectively). Patients with an anticoagulation during the dialysis session greater than 0.35 IU/kg/session had a longer bleeding time (12.75 min vs 11.75 min; P=0.008).

CONCLUSION

In our evaluation, the use of haemostatic dressings is not associated with a real shorter bleeding time. Their use generate an additional cost estimated on average at 164 euros/year/patient. Patients and team realized that compression time is important for fistula monitoring and using compresses does not really increase this time.

Interest of surgical vascular reconstructions aiming at preserving hemodialysis access

BACKGROUND

Vascular hemodialysis access is a very precious asset for patients with end-stage renal failure. Ideally complications in these accesses should be detected early in order to treat them in time. The aim of this study was to evaluate the effectiveness of vascular reconstructions to preserve the vascular access for hemodialysis and to examine their benefits in terms of conserving the venous network, using hemodialysis catheters, time of cannulation after surgery, patency and postoperative morbi-mortality, by comparing them to those of newly created arterio-venous fistula (AVF).

METHODS

This was a retrospective, descriptive and comparative study, performed from September 2012 to February 2015. It concerned patients operated for complications of their native AVF. Two groups were compared: reconstructed AVF (group 1) and newly created AVF (group 2). Demographic characteristics, comorbidities, preoperative clinical and paraclinical data, surgical techniques and outcomes were recorded. This data was analyzed and compared between the two groups.

RESULTS

We collected 151 surgical interventions divided into two groups: 55 surgical reconstructions and 96 new AVF. The average age was 59.9±1.3 years [19.1-88.9], with a male predominance (59.6%). The two groups were comparable in terms of age, gender and comorbidities. Reconstructions were mostly indicated for stenosis (47.3%) and new vascular accesses for venous thrombosis (92.7%). Reconstruction had significantly better successful exploitation rates (95.7%) and time of cannulation (26.6 days) (respectively P=0.025 and P=0.000). Its primary failure rate was null. Its primary patency and primary functional patency were respectively 94.2% and 97.7% at 1 month and 82.2% and 87.1% at 2 years. Morbidity's global rates were comparable between both groups (41.8% vs. 43.8%). The rates of early morbidity and stenosis were significantly higher for reconstructions (respectively P=0.037 and P=0.047), while late morbidity and thrombosis' rates were significantly higher for new AVF (respectively P=0.021 and P=0.023). Mid-term permeabilities were better for reconstructions, but the differences were not statistically significant.

CONCLUSION

Surgical reconstructions seem to be an effective alternative for the treatment of complicated AVF. Our results appear to be comparable to those of the literature. The benefits of these surgical techniques in terms of conserving venous network, use of hemodialysis catheters, time for cannulation after surgery, patency and postoperative morbi-mortality appear to be undeniable.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Difficult cannulation of hemodialysis arteriovenous fistula - Role of imaging in access management (DICAF STUDY)

BACKGROUND

Difficulty in cannulation of arteriovenous fistula (AVF) can lead to inadequate dialysis, transient to permanent loss of access and increases dependency on bridging catheters. This study aimed to analyze the causes for difficult fistula cannulation, using various imaging modalities.

METHODOLOGY

This was a retrospective single-center observational study conducted between October 2017 and June 2018. Patients whose fistulae were difficult to cannulate were initially evaluated by physical examination followed by doppler ultrasonography or/and fistulogram as necessary. The patients were divided into two groups that is, primary difficult cannulation (within first three months of creation of fistula) or secondary difficult cannulation (after three months).

RESULTS

We encountered difficult cannulation in 43 patients. About 60% were primary difficult cannulations. Most common causes for difficulty in cannulation were cannulation zone (CZ) stenosis (23.3%), immature fistula (20.9%), outflow stenosis (18.6%), inflow stenosis (11.6%), anatomical abnormalities (11.6%), outflow plus CZ stenosis (9.3%) and inflow plus CZ stenosis (4.7%). Among patients with primary difficult cannulation, immature fistula (34.6%) was the most common cause, whereas CZ stenosis (47.1%) was the most common etiology for secondary difficult cannulation. Edema leading to difficult cannulation was found in 12 patients (27.9%), all of which was due to central vein stenosis. Cannulation resulted in hematoma, fistula thrombosis, failure of fistula and pseudoaneurysm in 83.7%, 27.9%, 16.3%, and 2.3% of cases respectively. Bridging temporary dialysis catheter placement was required in 67.4% patients. Ultrasound doppler had lower diagnostic value when compared to fistulogram (71.4% vs 93.9%, p = 0.014).

CONCLUSION

Difficulty in cannulating the arteriovenous fistula is a common problem in hemodialysis patients. We suggest that patients whose fistulae are difficult to cannulate should undergo early radiological evaluation to decrease catheter dependency and access failure.

Nurses' Use of Ultrasound Location for Puncturing Arteriovenous Fistulas in Hemodialysis

Puncturing an arteriovenous fistula (AVF) in chronic hemodialysis (HD) patients is a source of difficulty even for experienced dialysis nurses. The objective of this study was to compare the failure rate of AVF puncture by the usual technique (visual or by palpation) and after ultrasound location. This nonrandomized prospective single-center study was carried out at the Safi HD Hospital Center for 16 weeks in two successive phases, with the time between each phase dedicated to training nurses in locating punctures by ultrasound. We first evaluated 30 HD patients (300 HD sessions, i.e., 600 punctures) without ultrasound location, then the same patients (300 sessions, i.e., 600 punctures) using ultrasound location for all punctures. Ultrasound location carried out by a single nurse did not show a significant reduction in the rate of failure to puncture the AVF compared with the standard method (2.6% vs. 4%, P = 0.07). However, the rate of complications at the puncture site, recourse to medical advice, or mobilization of a second nurse were significantly reduced (P < 0.05). This single-center study showed no advantage of this approach for the effective cannulation of AVF in HD patients known to be not difficult to cannulate.

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.

Arteriovenous Malformation Hemorrhage in Pregnancy: A Systematic Review and Meta-Analysis

Hemorrhage of arteriovenous malformation (AVM) is a rare condition during pregnancy. This study was proposed to pool the proportion of AVM hemorrhage per pregnancy. A systematic review and meta-analysis with three databases were performed to review the studies published until April 2022. The Newcastle Ottawa Scale was used for risk assessment of data quality. The meta-analysis was conducted by a generic inverse variance of double arcsine transformation with a random model using Stata software. Twelve studies were included in this review. The pooled proportion of AVM hemorrhage per pregnancy was 0.16 (95% CI: 0.08, 0.26). The subgroup analyses were carried out based on world regions and study designs, and the study duration with the highest proportion of each subgroup was Europe [0.35 (95% CI: 0.02, 0.79)], with retrospective review [0.18 (95% CI: 007, 0.32)] and 10 to 20 years of study duration [0.37 (95% CI: 0.06, 0.77)]. The AVM hemorrhage per pregnancy in this review was considered low. However, the conclusion must be carefully interpreted since this review had a small study limitation.

Upper limb exercise for arteriovenous fistula maturation in people requiring permanent haemodialysis access

BACKGROUND

The failure of arteriovenous fistulas (AVF) to mature is a major problem in patients with kidney failure who require haemodialysis (HD). Preoperative planning is an important factor in increasing functional AVF. Upper limb exercise has been recommended to gain AVF maturation. Studies of pre- and post-operative upper limb exercises in patients with kidney failure patients have been reported; however, the optimal program for this population is unknown due to inconsistent results among these programs.

OBJECTIVES

We aimed to determine if upper limb exercise would be beneficial for AVF maturation (prior to and post AVF creation) in patients with kidney failure and to improve AVF outcomes. This review also aimed to identify adverse events related to upper limb exercise.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 15 March 2022 through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov, and other resources (e.g. reference list, contacting relevant individuals, and grey literature).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs, comparing upper limb exercise training programs with no intervention or other control programs before or after AVF creation in patients with kidney failure. Outcome measures included time to mature, ultrasound and clinical maturation, venous diameter, blood flow in the inflow artery, dialysis efficacy indicator, vascular access function (functional AVF), vascular access complications, and adverse events.

DATA COLLECTION AND ANALYSIS

Study selection and data extraction were taken by four independent authors. Bias assessment and quality assessment were undertaken independently by two authors. The effect estimate was analysed using risk ratio (RR) with 95% confidence intervals (CI) for dichotomous data, or mean difference (MD) or standardised mean difference (SMD) for continuous data. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Nine studies (579 participants) were included, and seven studies (519 participants) conducting post-operative exercise training could be meta-analysed. Three comparisons were undertaken: (i) isotonic exercise training versus no intervention; (ii) isometric versus isotonic exercise training; and (iii) isotonic (high volume) versus isotonic exercise training (low volume). Due to insufficient data, we could not analyse pre-operative exercise training. Overall, the risk of bias was low for selection and reporting bias, high for performance and attrition bias, and unclear for detection bias. Compared to no intervention, isotonic exercise training may make little or no difference to ultrasound maturation (2 studies, 263 participants: RR 1.09, 95% CI 0.94 to 1.25; I² = 0%; low certainty evidence), but may improve clinical maturation (2 studies, 263 participants: RR 1.14, 95% CI 1.02 to 1.27; I² = 0%; low certainty evidence). Compared to isotonic exercise training, isometric exercise training may improve both ultrasound maturation (3 studies, 160 participants: RR 1.56, 95% CI 1.21 to 2.00; I² = 22%; low certainty evidence) and clinical maturation (3 studies, 160 participants: RR 1.80, 95% CI 1.18 to 2.76; I² = 53%; low certainty evidence). Venous diameter (3 studies, 160 participants: MD 0.84 mm, 95% CI 0.45 to 1.23; I² = 0%; low certainty evidence) and blood flow in the inflow artery (3 studies, 160 participants: MD 140.62 mL/min, 95% CI 38.72 to 242.52; I² = 0%; low certainty evidence) may be greater with isometric exercise training. It is uncertain whether isometric exercise training reduces vascular access complications (2 studies, 110 participants: RR 2.54, 95% CI 0.38 to 17.08; I² = 47%; very low certainty evidence). It is uncertain whether high volume isotonic exercise training improves venous diameter (2 studies, 93 participants: MD 0.19 mm, 95% CI -0.75 to 1.13; I² = 34%; very low certainty evidence) or blood flow in the inflow artery (1 study, 15 participants: MD -287.70 mL/min, 95% CI -625.99 to 60.59; very low certainty evidence) compared to low volume isotonic exercise training. None of the included studies reported time to mature, dialysis efficacy indicator, vascular access function, or adverse events.

AUTHORS' CONCLUSIONS

Our findings suggest that the current research evidence examining upper limb exercise programs is of low quality, attributable to variability in the type of interventions used and the overall low number of studies and participants.

Patient specific approach to analysis of shear-induced platelet activation in haemodialysis arteriovenous fistula

Shear-induced platelet activation (SIPAct) is an important mechanism of thrombosis initiation under high blood flow. This mechanism relies on the interaction of platelets with the von Willebrand factor (VWF) capable of unfolding under high shear stress. High shear stress occurs in the arteriovenous fistula (AVF) commonly used for haemodialysis. A novel patient-specific approach for the modelling of SIPAct in the AVF was proposed. This enabled us to estimate the SIPAct level via computational fluid dynamics. The suggested approach was applied for the SIPAct analysis in AVF geometries reconstructed from medical images. The approach facilitates the determination of the SIPAct level dependence on both biomechanical (AVF flow rate) and biochemical factors (VWF multimer size). It was found that the dependence of the SIPAct level on the AVF flow rate can be approximated by a power law. The critical flow rate was a decreasing function of the VWF multimer size. Moreover, the critical AVF flow rate highly depended on patient-specific factors, e.g., the vessel geometry. This indicates that the approach may be adopted to elucidate patient-specific thrombosis risk factors in haemodialysis patients.

Bindarit encapsulated nanoparticles prevent venous neointimal hyperplasia and restenosis in a murine angioplasty model

Monocyte and macrophage recruitment occur to the injured vessel wall after percutaneous transluminal angioplasty (PTA) of stenotic arteriovenous fistulas (AVF) through increased expression of MCP-1 leading to venous neointimal hyperplasia (VNH) and venous stenosis (VS). We hypothesized that adventitial delivery of Bindarit, an oral selective inhibitor of MCP-1, -2, and -3 encapsulated in poly lactic-co-glycolic acid (PLGA) nanoparticles embedded in a thermosensitive Pluronic F127 hydrogel (BN NP) could prevent VNH/VS formation in a murine model of PTA with AVF. Scanning electron microscope and dynamic light scattering were used to characterize the BN NP and control nanoparticles (NP C). Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used to study drug release kinetics. Immediately after PTA, in a murine model of AVF stenosis, BN NP or NP C was administrated to the adventitia of outflow veins. Animals were sacrificed 3 and 21 days later for gene expression, histomorphometric, and immunohistochemical analyses. Doppler ultrasound was performed weekly. There was no difference in the size and storage modulus of BN NP compared to controls. The pharmacokinetic analysis demonstrated increased drug release from BN NP when compared to controls. BN NP-treated vessels had reduced MCP-1, MCP-2, and MCP-3 gene, and protein levels, reduced macrophage/monocyte abundance, proinflammatory cytokines, and venous fibrosis resulting in positive vascular remodeling and improved patency with reduced VNH/VS. There was increased peak velocity 21 days after PTA in the BN NP group. Adventitial administration of BN NP to the outflow vein after PTA results in decreased VNH/VS.

Adapting a Dialysis Service for Delivery of Percutaneous Arteriovenous Fistulas

The percutaneous arteriovenous fistula (pAVF) is an exciting and novel addition to the vascular access options available to patients with end-stage kidney disease who require dialysis. Early clinical results have been promising, with high rates of maturation and low rates of reintervention. To successfully adapt an existing hemodialysis service to include the provision of pAVF formation, it is essential to identify and align the interests of key clinical and nonclinical stakeholders. Only through strong collaboration can the service be supported. The authors provide a comprehensive overview of the planning fundamentals required, including the referral pathway, screening and clinical assessment, and practical procedural elements and considerations, as well as follow-up requirements such as cannulation, fistula surveillance, and maintenance. Key staffing requirements are highlighted, including those pertaining to vascular US screening and dialysis nurse training. A broad and structured planning approach ensures that the entire network of key stakeholder interests is included and provides a strong foundation for a compelling business plan to attract the necessary funding and managerial support for the service. The authors present a systematic framework of the essential considerations necessary to facilitate the planning, funding, and ultimately delivery of a successful pAVF service. Online supplemental material is available for this article. ^©RSNA, 2022.

[A narrative review on arteriovenous fistula for hemodialysis]

Vascular access is the lifeline for hemodialysis patients. Autologous artero-venous fistula (AVF) is still the most popular vascular access for hemodialysis even if declining during the last decades. Compared to central venous catheters and vascular grafts, AVF is characterized by a lower risk of infection and lower number of hospitalizations, and by a better quality of life, higher dialysis efficiency, and more prolonged life expectancy for patients. Since the year 1966 when the two surgeons Cimino and Brescia had the idea of connecting the forearm vein and artery for chronic dialysis, several data have accumulated on surgical procedures, positioning of AVF (distal vs proximal), time for the first use, monitoring and surveilling. All guidelines suggest that special care should be given by monitoring and surveilling AVF to avoid its failure or fatal closing. Attention should be paid to the patient's vasculature before surgery, through the "maturation" phase and chronic use. Indeed, AVF requires constant and careful care. The crucial role is played by the patient itself in cooperation with devoted clinical staff participated by skilled nurses, nephrologists, surgeons, radiologists, and sonographers. Literature on AVF is evaluated and guidelines suggestions reported as well as the data attained by the Accesso Vascolare per Emodialisi (AVE) project. This project aimed to evaluate the benefits of monitoring and surveilling, operated by a multidisciplinary team on dialysis adequacy, AVF longevity, and patient's mortality.

Overview of hemodialysis access and assessment

OBJECTIVE

To provide family physicians with an evidence-based overview on the various methods of vascular access for hemodialysis (HD) and to provide a framework for the clinical assessment of HD access.

SOURCES OF INFORMATION

A MEDLINE literature search was conducted using the MeSH terms arteriovenous fistula, arteriovenous graft, central venous catheter, and hemodialysis (or haemodialysis), including all relevant English-language articles published between January 1995 and September 2021.

MAIN MESSAGE

The main types of permanent vascular access for HD are arteriovenous fistulas, arteriovenous grafts, and central venous catheters. A pragmatic, patient-centred approach is required when choosing the type of access for an individual. Common complications of vascular access creation include thrombosis, central venous stenosis, dialysis access steal syndrome, and arteriovenous fistula aneurysms.

CONCLUSION

Family physicians play an important role in the clinical assessment and monitoring of HD vascular access. A thorough clinical assessment can detect a failing arteriovenous fistula and any associated complications, which can allow for prompt investigation and intervention to restore functionality, maintain access longevity, and improve patient quality of life.

Risk Factors and Utility of Intraoperative Arteriovenous Fistula Blood Flow Level as a Surrogate Marker of Arteriovenous Fistula Failure in Patients with End-stage Renal Disease

An arteriovenous fistula (AVF) can fail for different reasons at each stage after its creation. The study aimed to analyze the associations of the clinical and laboratory parameters, including the intraoperative AVF blood flow, with AVF failure at different periods (3 weeks and 3, 6, 9, 12, 24, and 36 months) after the AVF's creation and to evaluate the usefulness of the intraoperative AVF blood flow as a surrogate marker of AVF failure in patients with end-stage renal disease (ESRD). This was a single-center, retrospective cohort study that included 130 patients with ESRD who underwent the creation of new radiocephalic AVFs. The associations of the preoperative clinical and laboratory parameters and intraoperative flow with AVF failure in the different observation periods were investigated. Intraoperative AVF blood flow was significantly associated with AVF failure from 3 weeks to 24 months (P <0.05). Hemoglobin level and the size of the anastomosis were significantly associated with AVF failure at 6 months (P <0.05). In the analysis of the receiver operating characteristic curve, intraoperative AVF blood flow was significant from 3 weeks to 24 months (P <0.05). The intraoperative blood flow with the greatest sensitivity and specificity was 205-225 mL/min. Intraoperative blood flow was independently associated with AVF failure from 3 weeks to 24 months after the AVF's creation. An intraoperative AVF blood flow of >225 mL/min is crucial for long-term AVF patency. The intraoperative AVF blood flow level could be a surrogate marker of AVF failure in ESRD patients.

[Vein of Galen aneurysmal malformation]

The vein of Galen aneurysmal malformation (VGAM) is a rare aneurysmatic cerebrovascular malformation in newborns and children. The VGAM results from an arteriovenous fistula between the persistent vein of Markowski (embryonic precursor of the vein of Galen) and deep choroidal arteries. The VGAM is the most common noncardiac cause of high-output cardiac failure in newborns. It may also cause hemorrhage, seizures, and liquor malabsorption resulting in hydrocephalus. Preferred treatment of VGAM is transarterial embolization (TAE) to reduce the arteriovenous shunt volume and allow normal brain development.

Effect of buttonhole cannulation versus rope-ladder cannulation in hemodialysis patients with vascular access: A systematic review and meta-analysis of randomized/clinical controlled trials

BACKGROUND

Safe and effective arteriovenous fistula (AVF) puncture techniques must be used to reduce harm to hemodialysis patients. The relative benefits of buttonhole (BH) cannulation over those of rope ladder (RL) cannulation for AVF remain unclear and inconsistent.

METHODS

This systematic review and meta-analysis was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Literature searches were conducted in June 2020 in multiple scientific databases including Cochrane library, CINAHL, PubMed/ Medline, Airiti Library, National Digital Library of Theses and Dissertations in Taiwan, Google scholar, Embase, and ProQuest. We included all randomized controlled trials (RCTs) and clinical controlled trials (CCTs) that explored the efficacy of BH cannulation in hemodialysis patients. These included reports published in either English or Chinese that enrolled adults aged 18 years or older who underwent hemodialysis using an autogenous AVF. Studies that showed poor design, such as use of a self-control group or no control group, were excluded from analysis. The critical appraisal skills program checklist for RCTs were used to assess the quality of the evidence and RevMan software were used to perform the meta-analysis.

RESULTS

Fifteen studies (11 RCTs and 4 CCTs) met the inclusion criteria and were used for the meta-analysis. Meta-analysis showed that BH cannulation significantly reduced aneurysm formation (RR = 0.18, 95% confidence interval [CI] [0.1, 0.32]), stenosis (RR = 0.44, 95% CI [0.25, 0.77]), thrombosis formation (RR = 0.4, 95% CI [0.2, 0.8]), and hematoma (RR = 0.63, 95% CI [0.40, 0.99]) and showed no differences in AVR infection (≦6 months, RR = 2.17, 95% CI [0.76, 6.23]; >6 months, RR = 2.7, 95% CI [0.92, 7.92]) compared to RL cannulation.

CONCLUSIONS

Given the benefits of BH, this meta-analysis found that BH cannulation should be recommended as a routine procedure for hemodialysis but that hospitals and hemodialysis clinics should strengthen staff knowledge and skills of BH cannulation to reduce the risk of AVF infection.

A proof-of-concept real-time processing to characterize vascular flow

In dialysis patients, monitoring vascular flow of the surgically created arteriovenous fistula (AVF) is critical to indicate the success of the AVF as a dialysis access site. Current gold standard to quantify vascular flow involves external doppler evaluation which requires frequent visits to the clinic. In this paper, we present a proof-of-concept cost-efficient vascular flow monitoring system towards a wearable and robust blood flow monitoring system. The proposed system captures beat-to-beat blood flow from impedance plethysmography (IPG) signal and performs embedded computing to robustly map the changes in the IPG to peripheral blood flow. We present the proof-of-concept results for the embedded real-time blood flow computing from measurements obtained using a custom electrical bioimpedance hardware presented previously elsewhere. We anticipate the results serving as the first step towards potentially eliminating the need for using expensive and bulky systems that require specialized personnel to operate for peripheral blood flow monitoring. Clinical relevance-The study paves the way to engineering a ubiquitous blood flow monitoring system for patients who have a surgically created Arteriovenous fistula (AVF) for dialysis vascular access.

Understanding burden of proof and equipoise in the design of pragmatic clinical trials: An example from a trial on brain arteriovenous malformations

BACKGROUND AND PURPOSE

The burden of proof principle is rarely discussed and poorly understood, but central to the proper design of pragmatic clinical trials. A better understanding of the principle could play an important role in the re-introduction of scientific methods within practice and in revising fundamental problems with the current research-care separation.

METHODS

We analyze the design of the ARUBA trial on the management of unruptured brain arteriovenous malformations. We also review how the concept of clinical equipoise was introduced to address a misconceived problem of research ethics.

RESULTS

The ARUBA trial hypothesis in favour of conservative management of brain arteriovenous malformations failed to take into account the fact that the burden of proof was on surgery, endovascular treatment or radiation therapy. Thus, results remained inconclusive and other trials are needed. The equipoise notion fails to take into account that the burden of proof is on unvalidated medical or surgical interventions, if we want to provide outcome-based medical care that patients can trust.

CONCLUSION

The burden of proof principle is essential to properly design pragmatic trials. This principle also explains why in certain circumstances optimal care is a randomized care trial.

Overcoming Health Literacy Barriers by Developing Standardized Surgical Discharge Instructions

INTRODUCTION

Approximately one-third of surgical patients exhibit low health literacy, and 39% of our patients are primary Spanish speakers. We first evaluated the current content of our arteriovenous fistula/graft discharge instruction (DCI) templates. Using the Plan-Do-Study-Act cycle quality improvement methodology, we then aimed to optimize the readability and formally translate new DCI and evaluate usage and inappropriate bouncebacks following implementation.

METHODS

Current arteriovenous fistula/graft template content was reviewed by the literacy department for readability and vascular faculty for completeness and accuracy. The literacy department edits were categorized by word choice, added/removed content, format change, and grammatical errors. Two vascular surgeons rated completeness and accuracy on a Likert scale (1-5). Retrospective chart review was performed for telephone calls and emergency department bouncebacks for 3 mo flanking new DCI implementation.

RESULTS

Of the 10 templates, all were in English and word count ranged from 192 to 990 words. Despite each template including all necessary subcategories, the median number of edits per 100 words was 9.2 [7.0-9.5]. Approximately half of the edits (5.4 [5.1-5.5]) were word choice edits. Overall, experts rated completeness at 3.9 [3.2-4.2] and accuracy at 4.0 [3.7-4.1]. Highest template utilization occurred during post-implementation months 1 (90%) and 3 (100%) with orientation sessions. There was a significant increase in concordant Spanish DCI use (P < 0.01) and no inappropriate bouncebacks after implementation.

CONCLUSIONS

Our study demonstrated notable variability in the content and readability of our vascular access instruction templates. New DCI had strong usage and language concordance; continued use may decrease bouncebacks.

Protocol for a qualitative study exploring haemodialysis dependent patients' arteriovenous fistula experience, values and concerns in Sydney, Australia

INTRODUCTION

The experiences of patients from culturally and linguistically diverse backgrounds, with chronic mental illness, disabilities or who identify as sexual or religious minorities are under-represented in clinical research on arteriovenous fistula (AVF) for haemodialysis access. A greater understanding of the experiences, values and concerns of these diverse patient groups are needed to provide haemodialysis access care that addresses the needs of all haemodialysis-dependent patients. This study seeks to describe a broad range of patient experiences related to the creation, care and surveillance of AVFs, including interactions with healthcare teams.

METHODS AND ANALYSIS

This qualitative study will use semistructured interviews with individual patients purposefully selected to provide a diverse patient population. A deliberate strategy will be used to recruit a demographically broad range of participants. Thematic analysis of interview transcripts, using a constant comparative methodology, will generate themes that describe patient experiences, values and concerns. Findings from this study will give a nuanced insight into the experiences of patients on haemodialysis with respect to their AVF.

ETHICS AND DISSEMINATION

Ethical approval for this study was provided by the Sydney Local Health District Human Research Ethics Committee (REGIS identifier: 2021/ETH00362, CH reference number: CH62/6/2021-033). Results will be made available to the participants, local health district, funders and other researchers through various hospital and academic forums. Data will also be published in peer-reviewed journals and be part of a larger body of work looking into patient-reported outcome measures for patients with AVF.

Brain Injury in Fetuses with Vein of Galen Malformation and Nongalenic Arteriovenous Fistulas: Static Snapshot or a Portent of More?

BACKGROUND AND PURPOSE

Brain injury in fetuses with vein of Galen malformations and nongalenic AVFs is a rare complication whose appearance, course, and prognosis are poorly studied. We sought to characterize the MR imaging features and examine associations with postnatal outcome.

MATERIALS AND METHODS

This was a retrospective analysis of fetal MRIs of subjects with vein of Galen malformation and nongalenic arteriovenous fistulas. Two pediatric neuroradiologists independently reviewed examinations to determine the presence of abnormalities on structural imaging (T1 volumetric interpolated breath-hold examination and T2-HASTE), DWI, and T2*-weighted images; discrepancies were adjudicated by a third reviewer. Radiologic progression of injury was determined by additional fetal or neonatal MRIs. A simple composite score evaluating poor neonatal clinical outcome as either intubation or death by postnatal day 2 was also queried. A body fetal imager evaluated the presence of systemic findings of right heart strain.

RESULTS

Forty-nine fetal MR imaging examinations corresponding to 31 subjects (27 vein of Galen malformations and 4 nongalenic AVF cases) were analyzed. Injury was observed in 8 subjects (26%) with 14 fetal examinations; the mean gestational age at identification of injury was 32.2 (SD 4.9) weeks. Structural abnormalities were present in all subjects with injury; restricted diffusion, in 5/7 subjects with available data; and T2* abnormalities, in all subjects with available data (n = 7). Radiologic progression was documented in all cases with follow-up imaging (n = 7). All subjects with fetal brain injury had a poor neonatal clinical outcome.

CONCLUSIONS

Brain injury in fetuses with vein of Galen malformation and nongalenic AVFs shows a combination of structural abnormalities, restricted diffusion, and blooming on T2* images. Injury appears to portend a poor prognosis, with relentless progression and a likely association with adverse neonatal outcomes.

Right Access, Right Time: How Nurses Can Advocate for Best Practice

Hemodialysis requires vascular access by way of an arteriovenous fistula (AVF), arteriovenous graft (AVG), or intravenous hemodialysis catheter. There is overwhelming evidence that an AVF should be the access of choice due to its lowest infection rate compared to an AVG or hemodialysis catheter; however, less than 17% of patients on hemodialysis have a functional AVF when hemodialysis treatment is initiated. Most patients with end stage kidney disease begin hemodialysis using a hemodialysis catheter, which has a higher infection rate. Nephrology nurses can advocate for best evidence-based practice, understanding that AVFs have lower infection and lower thrombosis rates, and provide more effective hemodialysis. This article provides a literature review for types and indications of hemodialysis access and how nurses can promote this best practice.