Successful Arteriovenous Fistula Research Articles

Efficacy of ultrasonography and color-Doppler for early prediction of hemodialysis arteriovenous fistula unassisted maturation.

Arteriovenous fistula (AVF) failure is a prevalent concern for patients with end-stage kidney disease on hemodialysis. Recognizing the efficacy of ultrasound Doppler in post-operative AVF evaluation, this study sought to discern the predictive capabilities of various ultrasonographic and color-Doppler metrics for early AVF outcomes. This single-center, prospective cohort study spanned 1 year and, post ethical clearance, included all patients who underwent native AVF creation surgery and were subsequently referred for standard post-operative ultrasound Doppler assessment. Parameters such as fistula size, cephalic vein area and diameter, and AVF flow velocity and rates were assessed on post-operative day 2, week 2, and week 6. These initial findings were juxtaposed with later outcomes to determine unassisted AVF results. Of the initial cohort of 40 patients, 75% encountered AVF failure, whereas 25% realized successful unassisted AVF maturation. A notable observation was the significant variance in AVF flow rates as early as post-operative day 2. A threshold of >246 ml/min was indicative of successful unassisted AVF maturation, leading to a sensitivity of 80% and a specificity of 70%. Although the cephalic vein diameter on post-operative day 2 lacked a robust association with AVF outcomes, a cut-off of >3.4 mm, when combined with flow rate testing, augmented the cumulative sensitivity to 92%. Ultrasound Doppler stands out as a valuable quantitative imaging modality, adept at prognosticating AVF outcomes from as early as post-operative day 2. In particular, a flow rate exceeding 246 ml/min and a cephalic vein diameter surpassing 3.4 mm are salient indicators for the early prediction of successful AVF outcomes.

Early Prediction of Native Arteriovenous Fistula for Maturation by Doppler Ultrasound Study

Introduction: There are significant chances of maturation failure in arteriovenous fistulas (AVFs) made for vascular access for hemodialysis. AVFs are usually assessed for maturation 6 weeks after the operation. Significant time is lost for performing a salvage radiological procedure or making an alternative AVF, in case the AVF fails to mature. Materials and Methods: This prospective observational study was conducted to predict the chances of maturation of AVF by Doppler ultrasound (USG) study. One hundred and thirty-seven patients in whom native AVF was made as a vascular access procedure for hemodialysis were included in the study. In five patients, palpable thrill was absent after 48 h of operation and were excluded from the study. The velocity of the blood, diameter of the vessel, and depth of the vessel from the skin were assessed by USG Doppler 3 weeks after the operation and were correlated with AVF maturation. Results: Successful maturation occurred in 114 (86.3%) AVF. The flow rate of the blood and depth of the vein were statistically different in successful and unsuccessful AVF maturation for both the groups of radial artery (RA) and brachial artery (BA) based AVF. For RA AVF, successful maturation was predicted by the flow rate of 539 mL/min (sensitivity 95% and specificity 83%) and 4.2 mm diameter of the vein (sensitivity 93% and specificity 100%). For BA AVF, successful maturation was predicted by the flow rate of 456 mL/min (sensitivity 93% and specificity 100%) and 5.7 mm diameter of the vein (sensitivity 77% and specificity 100%). The measurement of flow and depth at 3 weeks after AVF may predict the maturation of AVF. Conclusion: It will be beneficial to do a USG Doppler study 3 weeks after making AVF, as the measurement of flow may predict the maturation of AVF.

The role of glomerular filtration rate in AVF success: Should we intervene earlier?

End-stage kidney disease (ESKD) patients require life-sustaining kidney replacement therapies, with the natural arteriovenous fistula (AVF) being the preferred vascular access due to its low infection risk, high patency, and fewer complications. Factors like vessel diameter, gender, diabetes, age, and surgical technique influence AVF maturation. Our study focused on short-term AVF creation success, specifically examining estimated glomerular filtration rate (eGFR) levels using the CKD-EPI formula. Patients were categorized according to their eGFR levels to observe the effects of fistula timing and the severity of kidney disease. No significant demographic or outcome differences between eGFR groups have been observed except for gender. AVF maturation was notably associated with distal vein diameter (>2mm), while other factors did not significantly impact maturation rates. As a secondary outcome, it was concluded that the recording of patients' blood pressure values at preoperative and perioperative levels led to the conclusion that blood pressure levels may have an impact on fistula maturation. To ensure vascular access effectiveness, optimizing blood pressure, determining vein diameter, strategic AVF timing, and reducing catheter usage are crucial. Our study aimed to identify eGFR levels conducive to optimal AVF outcomes. Although significant results could not be obtained in this regard, it is considered worthwhile to re-examine the effect of blood pressure in secondary outcomes. Additionally, prospective studies may be appropriate for reevaluating the effect of GFR.

Snuffbox Versus Wrist Radiocephalic Arteriovenous Fistulas: 10 Years Experience.

Background The wrist radiocephalic arteriovenous fistula (RCAVF) is the initial suggested procedure for establishing hemodialysis vascular access (HVA) in the most distal site of the upper limb. The anatomical snuffbox arteriovenous fistula (SBAVF) is barely utilised, despite its remote location. In this study, we aimed to analyse and compare the results of SBAVF and RCAVF in terms of their maturity, patency, and failure rates. Methodology This descriptive, retrospective study compared outcomes between SBAVF and RCAVF in terms of maturation, patency, and failure. All patients with chronic kidney disease who attended and underwent either procedure at Betsi Cadwaladr University Health Board between 2013 and 2023 were studied. Results In a period of 10 years, 179 patients were included. Overall, 102 (57%) were male and 77 (43%) were female, with a male-to-female ratio of 1.3:1. Wrist radiocephalic fistula was the dominant type of surgery done in 76% (n = 136), while the snuffbox radiocephalic fistula was done in fewer than 24% (n = 43) of patients. Most patients underwent a successful arteriovenous (AV) fistula (n = 105, 58.7%), in contrast to 67 patients whose fistulas failed. There was a significant relationship between fistula failure and complications (p = 0.000). There was no significant effect of the fistula site, hypertension, diabetes, cardiac diseases, smoking, peripheral vascular disease, or central vein stenosis on the failure of the AV fistula (p = 0.127, 0.534, 0.510, 0.397, 0.017, 0.68, and 0.371, respectively). Conclusions The snuffbox AV fistula is a suitable and feasible first choice for patients on hemodynamic therapy.

Arteriovenous fistula access for dialysis using vessels of the arm

Background: Site selection, configuration of the access and technical performance of operation are keys to a successful arteriovenous fistula (AVF) for haemodialysis. Objective: To evaluate the primary success rate and complications of AVF performed in Port Harcourt using vessels of the arm. Materials and Methods: This was a prospective cross-sectional study on the success rate of the Arteriovenous fistulas done using vessels of the arm in patients with End Stage Renal Disease (ESRD) undergoing dialysis across public and private health facilities in Port Harcourt. The study was conducted between March 1, 2017, and February 29, 2024. Preoperatively, using a duplex scan (and sometimes through clinical examination) with and without a tourniquet, the selected vein size was ≥ 2.5mm and the artery ≥2mm with a healthy wall and good flow. Parameters monitored were thrill and bruit intra-operatively, immediate, one- week and 6-8 weeks post-operative periods; the size of the vein intra-operatively, one -week and 6-8 weeks post-operatively. In addition, the patients were monitored for complications. Data were analyzed using statistical packages for social sciences (SPSS) version 25. Th demographic data and medical information were summarized using descriptive statistics (mean, median, frequency percentage and standard deviation) as appropriate. Result: There were 87 patients during the period under review. The age range was 14-85years with mean age of 54 ± 6.4 years. Of these, 18 (20.69%) were females, and 69 (79.31%) were males; 92 AVFs were done in 87 patients (87 primary and 5 repeat) with ESRD for dialysis; 69 (75%) Brachiocephalic (BC) and 23 (25%) Brachiobasilic (BB)AVFs. The AVFs were primarily successful in 82 cases (94.25%), with 5 primary failures (5.75%), and a total of 5 repeat AVFs within this period, excluding secondary failures. Complications were 1 (1.15%) upper limb oedema, 6 (6.90%) delayed wound healing, 4 (4.60%) cases of seroma, 1 (1.15%) case of steal syndrome, 4 (4.60%) cases of spontaneous thrombosis and 3 (3.45%) cases of superficial wound infection. Conclusion: The primary success rate of AVF for dialysis in Port Harcourt using vessels of the arm is quite good with few complications.

Sociodemographic Disparities in Adults with Kidney Failure: A Meta-Analysis.

This meta-analysis aims to assess current evidence regarding sociodemographic disparities among adults with kidney failure. Medline, Scopus, Web of Science, CENTRAL, and Google Scholar were systematically searched from inception to 20 February 2022. Overall, 165 cohort studies were included. Compared to White patients, dialysis survival was significantly better among Black (hazard ratio-HR: 0.68; 95% CI: 0.61-0.75), Asian (HR: 0.67; 95% CI: 0.61-0.72) and Hispanic patients (HR: 0.80; 95% CI: 0.73-0.88). Black individuals were associated with lower rates of successful arteriovenous fistula use, peritoneal dialysis and kidney transplantation, as well as with worse graft survival. Overall survival was significantly better in females after kidney transplantation compared to males (HR: 0.87; 95% CI: 0.84-0.90). Female sex was linked to higher rates of central venous catheter use and a lower probability of kidney transplantation. Indices of low SES were associated with higher mortality risk (HR: 1.22, 95% CI: 1.14-1.31), reduced rates of dialysis with an arteriovenous fistula, peritoneal dialysis and kidney transplantation, as well as higher graft failure risk. In conclusion, Black, Asian and Hispanic patients present better survival in dialysis, while Black, female and socially deprived patients demonstrate lower rates of successful arteriovenous fistula use and limited access to kidney transplantation. PROSPERO registration: CRD42022300839.

Oblique versus Straight skin incision: The impact of incision type on postoperative outcomes in distal radiocephalic arteriovenous fistula creation

Aim: The type of skin incision utilized in arteriovenous (AV) fistula creation may significantly influence the patency, maturation, and overall outcomes of the fistulas. An oblique skin incision may offer distinct advantages in preventing early AV fistula failure by reducing skin tension and minimizing pressure on the newly formed anastomosis. This study aims to compare the postoperative early period outcomes of oblique versus straight skin incision techniques, with a focus on their impact on AV fistula success. Material and Methods: 2020 to 2023, all patients with created AV fistula via distal antebrachial vessels with oblique and straight skin incisions were enrolled. Retrospectively, the patients’ demographics, comorbidities were collated from the hospital data. All patients were operated with local anesthesia for radiocephalic AV fistula creation. The characteristics of the vessels were determined through preoperative Doppler ultrasonography mapping. Evaluations were conducted on primary patency, early maturation, and the incidence of early thrombosis. Results: In Total, 182 patients were operated for AV fistula creation. The mean age was 57±17 years and there was a male predominance with %68. We performed 74 patients AVF creation via straight skin incision and 108 via oblique skin incision. Despite there being no differences in comorbidities and demographic characteristics between the two groups, the group with a straight skin incision exhibited a higher incidence of early thrombosis (p=0.03), a lower maturation rate (p=0.03), and reduced primary patency (p=0.01). Conclusion: Oblique skin incision could be a feasible alternative to conventional straight incision with a higher early AVF patency and lower thrombosis rates. Reducing the pressure on and keeping the incision away from the new anastomosis may be crucial for achieving better outcomes.

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

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

Creating hemodialysis autogenous access in children and adolescents

ObjectiveEnd-stage renal disease (ESRD) in childhood and adolescence is rare, with relatively few published reports of pediatric ESRD vascular access. This study analyzes a 10-year experience creating arteriovenous fistulas (AVFs) in children and adolescents. Our goal is to review our strategy for creating functional autogenous vascular access in younger patients and report our results. MethodsWe retrospectively reviewed data and outcomes for consecutive vascular access patients aged ≤19 years during a 10-year period. Each patient had preoperative vascular ultrasound mapping by the operating surgeon in addition to physical examination. A distal forearm radiocephalic AVF was the first access choice when feasible, and a proximal radial artery inflow AVF was the next option. Demographic data, inflow artery, venous outflow target, and required transposition vs direct AVFs were variables included in the analysis. Primary and cumulative patency were calculated by Kaplan-Meier analysis. ResultsThirty-seven AVFs were created in 35 patients. No grafts were used. Ages were 6 to 19 years (mean, 15 years), and 20 were male. Causes of ESRD included glomerular disease (n = 18) and urinary obstruction or reflux (n = 7), among others. Three had previous AVFs, and 10 were obese. The proximal radial artery supplied AVF inflow in 25 patients and the brachial artery in only seven. Eleven individuals required a transposition and one a vein translocation to the contralateral arm. No patients developed hand ischemia, although two later required banding procedures for high flow. Eleven patients had successful transplants. A single patient died, unrelated to the vascular access. Five AVFs failed. Of these, two had new successful AVFs created, two regained renal function, one was transplanted, and one declined other procedures. Primary and cumulative patency rates were 75% and 85% at 12 months, 70% and 85% at 24 months, and 51% and 85% at 36 months, respectively. Median follow-up was 16 months. ConclusionsCreating an AVF for hemodialysis is a successful vascular access strategy for pediatric and adolescent patients. Proximal radial artery AVFs provided safe and functional access when a distal AVF was not feasible. Cumulative AVF patency was 85% at 36 months.

Pre-operative exercise therapy to increase blood vessel diameter in patients undergoing radiocephalic arteriovenous fistula creation

Background Post-operative upper extremity exercise is recommended to patients with arteriovenous fistulas. It is postulated that increased blood flow to vessels improves maturation and patency rates. Recent studies favour pre-operative exercise therapy to improve the outcomes of arteriovenous fistula creation. Objectives To investigate if pre-operative exercise therapy increases vessel diameter and maturation in patients undergoing distal arteriovenous fistula creation. Methods 34 patients planned for radiocephalic arteriovenous fistula creation were recruited at a tertiary university hospital Vascular Surgery Unit. Patients underwent a 6-week period of self-directed daily upper extremity exercises before surgery. Patients were reviewed up to 6 months post-surgery. The primary outcome investigated was change in venous and arterial diameters following exercise intervention. The secondary outcome investigated was the primary failure rate of the newly created arteriovenous fistulas. Results After exercise therapy, mean hand grip strength increased from 20.3 ± 6.62 kg to 21.9 ± 7.16 kg ( p=.01). There was a statistically significant increase in basilic vein diameter amongst those who demonstrated strict compliance to at least 42 days of pre-operative exercise therapy by 0.51 mm from 3.23 ± 1.09 mm to 3.74 ± 1.31 mm ( p=.03). Primary failure rate of newly created radiocephalic arteriovenous fistulas was 25% (7 of 28), comparable to our previous series of 436 distal arteriovenous fistulas created which had a failure rate of 26%. Conclusions There was a trend of increase in vein diameters after pre-operative exercise therapy. Although not statistically significant, patients with successful arteriovenous fistula creation had longer mean completion of exercise days.

#4606 INNOVATIVE METHOD TO EVALUATE MATURATION OF NEWLY CREATED ARTERIO-VENOUS FISTULAS: INSIGHTS FROM A QUALITY IMPROVEMENT PROJECT

Abstract Background and Aims Recently, we introduced central-venous oxygen saturation (ScvO2) and estimated upper-body blood flow (eUBBF) to monitor the maturation of newly created arterio-venous fistulas (AVF) in hemodialysis (HD) patients [1]. The approach was implemented in a clinical quality improvement project (QIP). Method The QIP involved two Renal Research Institute dialysis centers in New York City that use the Crit-Line monitor (CLM, Fresenius Medical Care, Waltham, MA, USA) as part of the standard of care. CLM measures automatically and non-invasively hematocrit and oxygen saturation (i.e., ScvO2 in patients with central venous catheter as vascular access). eUBBF was computed as described previously [1]. Patients with a with a newly created AVF were included, irrespective of their HD vintage. The QIP team comprised a registered nurse per clinic, two research physicians, and two data analysts. The team met weekly to assess the AVF maturation progress based on eUBBF and ScvO2 data that were displayed on a specific dashboard. Successful AVF maturation is typically accompanied by a rise in cardiac output and eUBBF that starts immediately after AVF creation. However, it is unknown what degree of eUBBF increase indicates a subsequently successful AVF maturation. To identify predictive eUBBF thresholds, we correlated eUBBF changes with the progress of AVF maturation in the six weeks following AVF creation. We defined maturation as unsuccessful when the newly created AVF required an intervention (e.g., angioplasty) or was abandoned. Results We studied 39 patients (age 56 ±18 years; 25 males). Twenty-eight of them were incident patients. Two patients had a second AVF created. In 15 patients AVF maturation was unsuccessful. In these patients, eUBBF increased to an average of 119.2% (SD 35.2) compared to pre-AFV creation. In patients with successful AFV maturation (N = 24), eUBBF increased to an average of 153.7% (SD 31.6) (Figure 1). The difference between the groups is 34.4 percentage points (95% CI: 12.4 to 56.4; p = 0.003). Using eUBBF as a diagnostic measure to discriminate successful vs. failed AVF maturation, an area under the receiver operating characteristics curve of 0.824 (95% CI: 0.673 to 0.925; p&amp;lt;0.0001) was obtained. An eUBBF increase of 25% had a sensitivity of 59% and a specificity of 92% to predict AVF maturation outcomes. Conclusion Computation of eUBBF provides a simple and non-invasive means to track AVF maturation and predict its outcomes.

Small Caliber Distal Cephalic Veins Undergo Significant Dilation under Anesthesia and Can Successfully Be Used for Arteriovenous Fistula Creation

Successful arteriovenous fistula (AVF) maturation and use for dialysis is highly dependent on preoperative diameter. Small veins (<2mm) exhibit high failure rates and are typically avoided. This study investigates the effects of anesthesia on the distal cephalic vein diameter as compared to preoperative outpatient vein mapping for the purpose of hemodialysis access creation. One hundred eight consecutive procedures for dialysis access placement met inclusion criteria and were reviewed. All patients received preoperative venous mapping and postanesthesia ultrasound mapping (PAUS). All patients received either regional and/or general anesthesia. A multiple regression was conducted to determine predictors of venous dilatation. The independent variables included both demographical and operative-specific variables such as the type of anesthesia. Outcomes of fistula maturation (successful cannulation and dialysis) were analyzed. In this cohort, the mean preoperative vein diameter was 1.85mm and the mean PAUS diameter was 3.45mm, a 2.21× increase, with only 2 patient veins failing to increase in diameter. Smaller veins (<2mm) exhibited significantly more dilation than larger veins after anesthesia (2.73 vs. 1.47×, P<0.001). In the multiple regression analysis, smaller vein diameter was correlated with a significantly greater degree of dilation (P<0.001). The degree of venous dilation was not affected by patient demographic-specific factors or by the type of anesthesia (regional block versus general) in the multiple regression analysis. 6month follow-up data for fistula maturation was available for 75 of 108 patients. Small veins (<2mm) on preoperative ultrasound matured at a similar rate as larger veins (90% vs. 91.4%, P=0.833). Small caliber distal cephalic veins experience a significant degree of dilation under regional and general anesthesia and can successfully be used for AVF creation. Consideration should be made to perform a postanesthesia vein mapping for all patients undergoing access placement despite preoperative venous mapping results.

Role of color Doppler assessment in predicting outcomes of wrist Brescia-Cimino arteriovenous fistula creation: A single-center prospective study.

The most common reason for constructing an arteriovenous fistula (AVF) is chronic kidney disease. Various factors are associated with nonmaturation or failure of AVF, which can be evaluated using color Doppler/duplex ultrasound (DUS). We carried out this study to evaluate the role of pre- and postoperative DUS for the prediction of outcomes of wrist radiocephalic (RC) AVF. In our prospective observational study, dialysis-dependent patients between 20 and 70 years of age undergoing primary RC-AVF from May 2019 to July 2020 were included. All patients underwent pre- and postoperative DUS examination after obtaining consent. Among 104 participants, 87 (83.7%) were male and 17 (16.3%) were female. Successful maturation was seen in 68 (65.4%) participants, whereas 90 (86.53%) had functional maturation. Radial artery diameter (RAD) ≥1.6 mm, cephalic vein diameter (CVD) ≥2.0 mm, vein distensibility (VD) ≥0.5 mm, and peak systolic velocity (PSV) RAD ≥30 cm/s were associated with higher successful maturation of AVF with statistically significant results (P < 0.05). RAD ≥1.6 mm, CVD ≥2.0 mm, VD ≥0.5 mm, and PSV RAD ≥30 cm/s were related to a greater probability of RC-AVF maturation. Among them, VD and PSV-RA were the most influencing factors predicting RC-AVF successful maturation. If we consider the rule of six for AVF maturation, then the results will be much less than the actual fistulas which are dialyzable with adequate blood flow as per functional maturation criteria. Thus, more randomized studies are needed to define maturation criteria for the Indian population and to identify the effect of papaverine on successful AVF maturation.

The blood flow rate on the first day after arteriovenous fistula creation is a predictor of successful fistula maturation.

The determination of blood flow rate (BFR) is a useful tool for assessing the function of arteriovenous fistula (AVF). Eighty patients with a newly created radio cephalic AVF were analyzed. Hemodynamics and morphological characteristics of the blood vessels were assessed by Doppler ultrasound. The mean age of patients was 59.9± 13.5 years. A successful rate of AVF maturation was 62.5% at 8 weeks. Six adjusted models of multivariate analysis showed that BFR at Day 1 was a predictor for AVF maturation both at 4 weeks (p< 0.001) and 8 weeks (p< 0.001). Receiver operating characteristic analysis showed an optimal cut-off point for BFR at Day 1 of 395 ml/min for successful maturation at 4 weeks (sensitivity 0.714, specificity 0.889) and 344ml/min for successful maturation at 8 weeks (sensitivity 0.860, specificity 0.867). BFR at Day 1 is a powerful predictor for successful AVF maturation at 4 and 8 weeks.

Collagen, Hemodynamics, and Wall Mechanics of Failed vs. Successful Arteriovenous Fistulas From a Single Patient

Collagen, Hemodynamics, and Wall Mechanics of Failed vs. Successful Arteriovenous Fistulas From a Single Patient

Predicting radiocephalic arteriovenous fistula success with machine learning

After creation of a new arteriovenous fistula (AVF), assessment of readiness for use is an important clinical task. Accurate prediction of successful use is challenging, and augmentation of the physical exam with ultrasound has become routine. Herein, we propose a point-of-care tool based on machine learning to enhance prediction of successful unassisted radiocephalic arteriovenous fistula (AVF) use. Our analysis includes pooled patient-level data from 704 patients undergoing new radiocephalic AVF creation, eligible for hemodialysis, and enrolled in the 2014–2019 international multicenter PATENCY-1 or PATENCY-2 randomized controlled trials. The primary outcome being predicted is successful unassisted AVF use within 1-year, defined as 2-needle cannulation for hemodialysis for ≥90 days without preceding intervention. Logistic, penalized logistic (lasso and elastic net), decision tree, random forest, and boosted tree classification models were built with a training, tuning, and testing paradigm using a combination of baseline clinical characteristics and 4–6 week ultrasound parameters. Performance assessment includes receiver operating characteristic curves, precision-recall curves, calibration plots, and decision curves. All modeling approaches except the decision tree have similar discrimination performance and comparable net-benefit (area under the ROC curve 0.78–0.81, accuracy 69.1–73.6%). Model performance is superior to Kidney Disease Outcome Quality Initiative and University of Alabama at Birmingham ultrasound threshold criteria. The lasso model is presented as the final model due to its parsimony, retaining only 3 covariates: larger outflow vein diameter, higher flow volume, and absence of >50% luminal stenosis. A point-of-care online calculator is deployed to facilitate AVF assessment in the clinic.

Vascular Factors Affecting Outcomes of Snuffbox AV Fistula with Side-to-Side Anastomosis: A Single Institutional Observational Study

Background: Angioaccess is considered the "Tendon of Achilles" for hemodialysis. Arteriovenous fistula (AVF) is the commonly entailed vascular access for hemodialysis. Objectives: The present study evaluates the outcomes of anatomical snuffbox AVF by preoperative and postoperative color Doppler scans. It also determines the anatomical snuffbox AVF maturation rate concerning preoperative radial artery diameter (RAD), cephalic vein diameter (CVD), cephalic vein distensibility, and peak systolic velocity (PSV). Methods: This study was conducted from April 2020 to January 2021 on end-stage renal diseases (ESRD) patients undergoing an operation for anatomical snuffbox AVF creation at our center after taking permission from the institutional ethics committee and written informed consent from patients. Results: Thirty-five ESRD patients underwent snuffbox arteriovenous fistula (SBAVF) creation, including 68% males and 32% females. Diabetes mellitus was noted in 40% and hypertension in 80%. Successful AVF maturation was noted in 92% (69.57% of males and 30.43% of females). The mean RAD assessed on color Doppler ultrasonography (CDUS) preoperatively was 1.79 mm, while the peak velocity of the radial artery at the snuffbox was 23.80 cm/s. Conclusions: We recommend applying the side-to-side configuration as its anastomosis angle is less owing to the lesser kink on the anastomotic site. A longer segment of anastomosis is achieved, and better fluid dynamics and WSS profiles are seen in this configuration with good outcomes.

Patient-specific computational haemodynamics associated with the surgical creation of an arteriovenous fistula

Despite arteriovenous fistulae (AVF) being the preferred vascular access for haemodialysis, high primary failure rates (30-70%) and low one-year patency rates (40-70%) hamper their use. Furthermore, AVF creation has been associated with haemodynamic changes causing maladaptive cardiac remodelling leading to cardiovascular (CV) complications. In this study, we present a new workflow for characterising the haemodynamic profile prior to and following surgical creation of a successful left radiocephalic AVF in a 20-year-old end-stage kidney disease patient. The reconstructed vasculature was generated using multiple ferumoxytol-enhanced magnetic resonance angiography (FeMRA) datasets. Computational fluid dynamics (CFD) simulations utilising a scale-resolving turbulence model were completed to investigate the changes in the proximal haemodynamics following AVF creation, in addition to the post-AVF juxta-anastomosis flow patterns, which is impractical to obtain in-vivo. Following AVF creation, a significant 2-3-fold increase in blood flow rate was induced downstream of the left subclavian artery. This was validated through comparison with post-AVF patient-specific phase-contrast data. Proximal to the anastomosis, the increased flow rate yielded an increase in time-averaged wall shear stress (WSS), which is a key marker of adaptive vascular remodelling. In the juxta-anastomosis region, the success of the AVF was discussed with respect to the National Kidney Foundation's vascular access guidelines, where the patient-specific AVF met the flow rate and geometry criterion. The AVF venous diameter exceeded 6mm and the venous flow rate surpassed 600mL/min. This workflow may potentially be significant clinically when applied to multi-patient cohorts, with population-wide patient-specific conclusions being ascertained for the haemodynamic assessment of AVFs and improved surgical planning.

Good outcomes for arteriovenous fistula with buttonhole cannulation for chronic hemodialysis in children and adolescents.

Arteriovenous fistula (AVF) is the preferred access for chronic hemodialysis (HD) in children and adolescents, but central venous catheter use is still high. Retrospective chart review of children and adolescents with AVF created between January 2003 and December 2015 was performed to assess primary failure (PF), maturation time, functional primary and functional cumulative patency, and potential risk factors for AVF dysfunction. Ninety-nine AVF were created in 79 patients (54% male; 7-24 years; 16-147 kg) by experienced surgeons. Duplex ultrasonography vein mapping was used to assist with site selection. PF occurred in 17 AVF (17%) in 14 patients. Patient age, gender, ethnicity, underlying disease, time on dialysis, and AVF site were not associated with PF or patency. Coagulation abnormality was positively associated with PF (p = 0.03). Function was achieved in 82 AVF (83%) in 77 patients (97%). Median maturation time was 83 days (range 32-271). AVF were accessed via buttonholes. Functional primary patency was 95%, 84%, and 53% at 1, 2, and 5 years. Overall 1- and 2-year functional cumulative patency was 95%, but lower for small patients 16-30 kg (88%) and those greater than 80 kg (91%). The 5-year patency rate was 80%, but significantly lower for 16-30 kg (59%) and greater than 80 kg (55%). Risk analysis showed significantly better patency for 31-45 kg and 46-80 kg groups (p < 0.01), non-obese BMI (p = 0.01), and buttonhole self-cannulation (p = 0.03). This study provides more information about successful AVF with buttonhole cannulation in pediatric hemodialysis patients lending additional support for AVF use in pediatrics. A higher resolution version of the Graphical abstract is available as Supplementary information.

MO777: The Impact of Morphological and Haemodynamic Characteristics of Blood Vessels on the Arteriovenous Maturation

Abstract BACKGROUND AND AIMS Doppler Ultrasound (DUS) is a superior tool for the assessment of arteriovenous fistula (AVF) functionality. The aim of the study was to determine the association between morphological and haemodynamic characteristics of the blood vessels with AVF maturation. METHOD The study was prospective that analysed 80 patients with chronic kidney disease (CKD) stage 4/5 and CKD stage 5 on haemodialysis (CKD5D) with newly created radio cephalic AVF. Haemodynamics and morphological evaluation of blood vessels by DUS was performed in all patients. The diameter of the cephalic vein, radial and brachial artery was measured: before creation, on the first day (24-h after creation) and at 4 weeks. The blood flow (BF) rate of AVF was calculated by DUS on day 1, at 4 and 8 weeks. The successful maturation of AVF was defined with BF ≥ 600 mL/min. RESULTS The mean age of the patients was 59.9 ± 13.5 years, of which 46 (57.50%) were males. Successful AVF maturation at 4 weeks was 43.75% and 62.5% at 8 weeks. The results of six adjusted models in multivariate analyses showed BF rate on day 1 was a predictor for AVF maturation at 4 (P &amp;lt;0.001) and 8 weeks (P &amp;lt;0.001). The receiver operating characteristic (ROC) analyses showed that the highest sum of sensitivity and specificity for the BF on day 1 was 395 mL/min (sensitivity 0.714 and specificity 0.889) for the outcome at 4 weeks; and 344 mL/min (sensitivity 0.860 and specificity 0.867) for the outcome measured at 8 weeks. The diameter of the blood vessel was AVF significantly larger in patients with mature AVF compared with patients with non-mature AVF. Male gender was significantly associated with AVF maturation of AVF at fourth week (P &amp;lt; 0.001) and at eighth week (P = 0.001) compared with the female gender. CONCLUSION Our study showed that BF rate of AVF on day 1 was a predictor for AVF maturation at 4 and 8 weeks. The diameter of blood vessels and male gender were statistically associated with AVF maturation.