Radiocephalic Arteriovenous Fistula Creation Research Articles

Evaluating the Effectiveness of Systemic Heparin During Arteriovenous Fistula Creation by Emulating a Target Trial.

Most of the 800,000 people living with end-stage kidney disease in the United States rely on a functioning vascular access to provide life-sustaining hemodialysis, yet one-third of arteriovenous fistulas experience early failures. Determining the safety and effectiveness of systemic heparin during fistula creation could improve the quality and quantity of life for these vulnerable patients. In this paper, a pragmatic randomized trial was emulated to assess the effect of systemic heparin administration (vs. none) during radiocephalic arteriovenous fistula creation on early bleeding and thrombosis using data from two international multicenter randomized trials performed between 2014 and 2019. Marginal risks were estimated using inverse probability weighted parametric survival analysis and confidence intervals were generated with bootstrapping. A total of 914 patients were enrolled and 61% received systemic heparin; median (IQR) age was 58 (49, 67) years and 45% were on hemodialysis at enrollment. No difference in the risk of bleeding events was observed, with a risk difference (95% CI) at 14 days of -0.1% (-1.6, 1.4). The risk of access thrombosis was lower in the heparin group, with a risk of 3.7% (2.6, 4.8) after heparin and 5.3% (3.4, 7.4) without heparin at 14 days (risk ratio 0.72, 95% CI 0.50, 0.98).

Predicting recurrent interventions after radiocephalic arteriovenous fistula creation with machine learning and the PREDICT-AVF web app.

Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines discourage ongoing access salvage attempts after two interventions prior to successful use or more than three interventions per year overall. The goal was to develop a tool for prediction of radiocephalic arteriovenous fistula (AVF) intervention requirements to help guide shared decision-making about access appropriateness. Prospective cohort study of 914 adult patients in the United States and Canada undergoing radiocephalic AVF creation at one of the 39 centers participating in the PATENCY-1 or -2 trials. Clinical data, including demographics, comorbidities, access history, anatomic features, and post-operative ultrasound measurements at 4-6 and 12 weeks were used to predict recurrent interventions required at 1 year postoperatively. Cox proportional hazards, random survival forest, pooled logistic, and elastic net recurrent event survival prediction models were built using a combination of baseline characteristics and post-operative ultrasound measurements. A web application was created, which generates patient-specific predictions contextualized with the KDOQI guidelines. Patients underwent an estimated 1.04 (95% CI 0.94-1.13) interventions in the first year. Mean (SD) age was 57 (13) years; 22% were female. Radiocephalic AVFs were created at the snuffbox (2%), wrist (74%), or proximal forearm (24%). Using baseline characteristics, the random survival forest model performed best, with an area under the receiver operating characteristic curve (AUROC) of 0.75 (95% CI 0.67-0.82) at 1 year. The addition of ultrasound information to baseline characteristics did not substantially improve performance; however, Cox models using either 4-6- or 12-week post-operative ultrasound information alone had the best discrimination performance, with AUROCs of 0.77 (0.70-0.85) and 0.76 (0.70-0.83) at 1 year. The interactive web application is deployed at https://predict-avf.com. The PREDICT-AVF web application can guide patient counseling and guideline-concordant shared decision-making as part of a patient-centered end-stage kidney disease life plan.

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.

Predicting Recurrent Interventions After Radiocephalic Arteriovenous Fistula Creation with Machine Learning and the PREDICT-AVF Web App

Radiocephalic arteriovenous fistulas (AVFs) are often criticized for requiring numerous recurrent interventions to achieve and maintain hemodialysis access function. Recent Kidney Disease Outcomes Quality Initiative guidelines discourage ongoing access salvage attempts after two interventions prior to successful use or more than three interventions per year overall. This study's goal was to develop a useful prediction tool for preoperative and postoperative assessment of intervention requirements to help guide decision-making about access appropriateness and futility. The data source was patient-level data from the international multicenter PATENCY-1 and PATENCY-2 randomized controlled trials, which enrolled patients undergoing new radiocephalic AVF creation. Routine ultrasounds were performed at 4 to 6 weeks and 12 weeks from AVF creation and interpreted by a core laboratory. The outcome for the prediction models was the number of recurrent surgical or endovascular interventions required at 1 year. Cox, random survival forest, pooled logistic, and penalized pooled logistic (elastic net) recurrent event survival prediction models were built using a combination of baseline characteristics and postoperative ultrasound measurements. Models were trained with 10-fold cross-validation hyperparameter selection within a randomly split training dataset. Discrimination and calibration performance was assessed on a holdout testing dataset. An interactive web application was built, which generates patient-specific predictions at 1 year, draws cumulative hazard curves, and contextualizes the predictions with the Kidney Disease Outcomes Quality Initiative guidelines for recurrent interventions after access creation. The cohort included 914 patients; mean age was 57 ± 13 years and 22% were female. Radiocephalic AVFs were created at the snuffbox (2%), wrist (74%), or proximal forearm (24%). Patients underwent a median of 1.04 (95% confidence interval [CI], 0.95-1.13) interventions in the first year. Using only baseline characteristics, the random survival forest model performed best, with a C-statistic of 0.72 (95% CI, 0.65-0.78) at 1 year (Table). The addition of ultrasound information to baseline characteristics did not substantially improve performance; however, Cox models using either 4- to 6-week or 12-week postoperative ultrasound information alone had the best discrimination performance, with C-statistics of 0.74 (95% CI, 0.67-0.81) and 0.78 (95% CI, 0.72-0.84) at 1 year (Table). The interactive web application is deployed at PREDICT-AVF.com (Figure). When assessing candidates for radiocephalic AVF in the preoperative setting, baseline patient characteristics can predict future interventions with moderate performance. In the postoperative setting, ultrasound findings alone are sufficient to predict future interventions. A free point-of-care web application can guide patient counseling and guideline-concordant surgeon decision-making as part of a patient-centered end-stage kidney disease life plan.TableDiscrimination performance of each model and feature set, measured by the area under the receiver operating characteristic curve (C-statistic) at 1 year postoperativelyFeaturesCoxRandom survival ForestPooled logistic regressionElastic netBaseline0.704 (0.639-0.769)0.715 (0.647-0.783)0.696 (0.631-0.762)0.703 (0.638-0.769)Baseline + 4- to 6-week US0.704 (0.629-0.779)0.737 (0.666-0.808)0.702 (0.627-0.778)0.703 (0.627-0.778)Baseline + 12 week US0.737 (0.670-0.803)0.766 (0.701-0.832)0.730 (0.663-0.797)0.746 (0.680-0.812)4- to 6-Week US0.743 (0.674-0.813)0.696 (0.620-0.773)0.740 (0.670-0.810)0.742 (0.672-0.812)12-Week US0.782 (0.722-0.842)0.721 (0.652-0.791)0.774 (0.712-0.835)0.775 (0.714-0.837)US, Ultrasound.Perfect discrimination corresponds to an area under the receiver operating characteristic curve of 1. Feature sets included baseline (age, sex, race, smoking status, diabetes, heart failure, renal transplant history, anticoagulation use, antiplatelet use, statin use, hemodialysis status at the time of arteriovenous fistula creation, central venous catheter history, number of prior failed accesses, vein and artery diameter, anastomotic suture technique, access location, and access side), baseline with the addition of postoperative ultrasound measurements (flow volume, access diameter, and luminal stenosis), and ultrasound measurements alone. Open table in a new tab

Comparative Study between Different Modalities of Creation of Radiocephalic Arteriovenous Fistula Around the Wrist for Hemodialysis

Comparative Study between Different Modalities of Creation of Radiocephalic Arteriovenous Fistula Around the Wrist for Hemodialysis

Evaluating national guideline concordance of recurrent interventions after radiocephalic arteriovenous fistula creation

ObjectiveRadiocephalic arteriovenous fistulas have been historically perceived as requiring multiple follow-up procedural interventions to achieve maturation and maintain patency. Recent clinical practice guidelines from the National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative (KDOQI) emphasize a patient-centered hemodialysis access strategy with new maximum targets for intervention rates, potentially conflicting with concomitant recommendations to prioritize autogenous forearm hemodialysis access creation. The present descriptive study seeks to assess whether radiocephalic fistulas can meet the KDOQI guideline benchmarks for interventions following access creation, and to elucidate clinical and anatomic characteristics associated with the timing and frequency of interventions following radiocephalic arteriovenous fistula creation. MethodsProspective patient-level data from the multicenter PATENCY-1 and PATENCY-2 randomized trials, which enrolled patients undergoing new radiocephalic arteriovenous fistula creation, was analyzed (ClinicalTrials.govNCT02110901 and NCT02414841). The primary outcome was the rate of interventions at 1 year postoperatively. Incidence rates were calculated, and time to surgical or endovascular intervention following fistula creation was modeled using recurrent event extensions of the Cox proportional hazards model. Confidence intervals at the 95% level were calculated using nonparametric bootstrapping. ResultsThe cohort consisted of 914 patients; mean age was 57 years (standard deviation, 13 years), and 22% were female. Median follow-up was 707 days (interquartile range, 447-1066 days). The incidence of interventions per person-year was 1.04 (95% confidence interval [CI], 0.95-1.13) overall; 1.10 (95% CI, 0.98-1.21) before fistula use, and 0.96 (95% CI, 0.82-1.11) after fistula use. The most common interventions overall were balloon angioplasty (54.9% of all interventions), venous side-branch ligation (16.4%), and open revisions (eg, proximalization from snuffbox to wrist, 16.4%). The locations requiring balloon angioplasty included the juxta-anastomotic segment (51.7% of angioplasties), the outflow vein (29.2%), the inflow artery (14.8%), the central veins (3.8%), and the cephalic arch (0.5%). Common indications were to restore or maintain patency (75.6% of all interventions), assist maturation (14.9%), improve depth (4.4%), or improve augmentation (3.0%). In the multivariable regression analysis, female sex (adjusted hazard ratio [HR], 1.21; 95% CI, 1.05-1.45), diabetes (HR, 1.21; 95% CI, 1.01-1.46), and intraoperative vein diameter <3.0 mm (vs ≥4.0 mm: HR, 1.33; 95% CI, 1.02-1.66) were associated with earlier and more frequent interventions. Patients not on hemodialysis at the time of fistula creation underwent less frequent interventions (HR, 0.69; 95% CI, 0.59-0.81). ConclusionsPatients with radiocephalic arteriovenous fistulas can expect to undergo one intervention, on average, in the first year after creation, which aligns with current KDOQI guidelines. Patients already requiring hemodialysis, female patients, patients with diabetes, and patients with intraoperative vein diameters <3.0 mm were at increased risk for repeated intervention. No subgroup exceeded guideline-suggested maximum thresholds for recurrent interventions. Overall, the results demonstrate that creation of radiocephalic arteriovenous fistula remains a guideline-concordant strategy when part of an end-stage kidney disease life-plan in appropriately selected patients.

Modified no-touch technique for radio-cephalic arteriovenous fistula increases primary patency and decreases juxta-anastomotic stenosis.

Low primary patency rate is a major problem of radio-cephalic arteriovenous fistula (RC-AVF) creation. Radial artery deviation and reimplantation (RADAR) is associated with low juxta-anastomotic stenosis rate. However, inflow artery stenosis is prominent with RADAR. To further reduce injury to veins and arteries during operation, a modified no-touch technique (MNTT) was used to create RC-AVF. We retrospectively reviewed our prospectively maintained database of patients with end-stage renal disease (ESRD)s undergoing RC-AVF creation for hemodialysis using either the MNTT between January 2021 and January 2022 (MNTT group) or conventional surgical procedure ( end-to-side vein-to-artery anastomosis) between October 2016 and October 2017 (Control group). Patients who chose to undergo RC-AVF surgery underwent standardized preoperative mapping and postoperative fistula evaluations using duplex ultrasound. Additionally, 4D flow MRI data were used to visualize and quantify the hemodynamics of one RC-AVF by MNTT. Outcomes included primary patency, juxta-anastomotic stenosis, and maturation rates. Forty patients underwent RC-AVFs by MNTT, compared to 60 patients in the control group. The MNTT group had a higher primary unassisted patency rate than the control group (p = 0.038). Juxta-anastomotic stenosis (all on the cephalic vein) occurred in 4 (10%) patients who underwent MNTT. RC-AVF maturation rates after 3 months were not different between both groups (maturation rate: 90% and 81.7% in the MNTT and control groups, respectively, p = 0.253). COX regression showed that both conventional AVF surgery (p = 0.031) and smaller cephalic vein diameter (p = 0.034) were associated with higher odds of RC-AVF failure. The AVF flow within the proximal vein remained helical during cardiac cycle. The distribution of wall shear stress (WSS) and oscillatory shear index (OSI) differed from that of conventional surgical AVF. RC-AVF by MNTT increases primary patency rate and decreases juxta-anastomotic stenosis rate. The improvement in hemodynamics may be one of the important reasons for the better patency rate of in the RC-AVF by MNTT group.

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.

Recurrent Interventions after Radiocephalic Arteriovenous Fistula Creation: A Post Hoc Analysis of Randomized Controlled Trials

Recurrent Interventions after Radiocephalic Arteriovenous Fistula Creation: A Post Hoc Analysis of Randomized Controlled Trials

Outcome of Radiocephalic Arteriovenous Fistula Constructed Under Brachial Plexus Block Versus Local Anesthesia: A Randomized Controlled Trial

Backgrounds: Hemodialysis (HD) is the commonest modality of renal replacement therapy (RRT) which needs vascular access. Ideal vascular access should be well functional, durable, stable, and have fewer complications. An arteriovenous fistula (AVF) is the preferred form of vascular access and is recommended by Kidney Disease Improving Global Outcome (KDIGO) guidelines. Most of the AVFs are constructed under local anesthetic infiltration which has a high failure rate which is about 30-40% for radiocephalic arteriovenous fistula (RCAVF). This study aimed to change the anesthetic technique to brachial plexus block (BPB) for RCAVF creation to improve the primary patency rate and reduce early thrombotic complications. Objectives: The objective was to see the effect of brachial plexus block (BPB) on the outcome of AVF creation by primary patency rate, maturation time, primary functional patency rate, and complications. Materials and Method: This was a randomized controlled trial conducted in the Department of Urology, Bangabandhu Sheikh Mujib Medical University, Dhaka from December 2018 to December 2019. A total of 80 patients were selected from the study population according to inclusion and exclusion criteria. Then divided into two groups by simple random sampling. In the group, A RCAVF constructed under BPB, and group B RCAVF was constructed under LA. The standard operation technique of AVF construction was followed. Evaluation of AVFs was done at 3rd POD, 2nd week, 6th week, and 12th weeks to see the functional status and any complications. Doppler US was done at the 6th week routinely. Results: Among these 80 patients 3 patients were lost from the follow-up, two from group A and one from group B. There was no significant difference in age, sex, comorbidities, and HD status between the groups. There was higher primary patency in group A at 3rd POD and 2nd weeks but was not statistically significant. In the 6th week primary patency in group A was 33/38 (86.8%) and in group B 25/39(64.1%), p=0.033. In the 12th week, primary patency and functional primary patency rate were in group A was 33/38 (86.8%) and in group B 25/39(64.1%), p=0.033 and statistically significant. No significant difference in maturation time between the groups. Thrombosis was the most common complication, 14 in group B and 5 in group A. One BPB was failed but there was no significant complication related to BPB. Conclusion: Radiocephalic arteriovenous fistula constructed under brachial plexus block has better primary patency and functional primary patency than local anesthesia at 6th and 12th week. Early thrombotic complications were higher in AVF creation under local anesthetic infiltration. Anaesthesia with BPB can be used for primary radiocephalic AVF construction surgery to improve the outcome of RCAVF fistula and early complications. Bangladesh J. Urol. 2021; 24(2): 129-134

Radiocephalic Arteriovenous Fistula Patency and Use: A Post Hoc Analysis of Multicenter Randomized Clinical Trials.

Objective:We sought to confirm and extend the understanding of clinical outcomes following creation of a common distal autogenous access, the radiocephalic arteriovenous fistula (RCAVF).Background:Interdisciplinary guidelines recommend distal autogenous arteriovenous fistulae as the preferred hemodialysis (HD) access, yet uncertainty about durability and function present barriers to adoption.Methods:Pooled data from the 2014-2019 multicenter randomized-controlled PATENCY-1 and PATENCY-2 trials were analyzed. New RC-AVFs were created in 914 patients, and outcomes were tracked prospectively for 3-years. Cox proportional hazards and Fine-Gray regression models were constructed to explore patient, anatomic, and procedural associations with access patency and use.Results:Mean (SD) age was 57 (13) years; 45% were on dialysis at baseline. Kaplan-Meier estimates of 3-year primary, primary-assisted, and secondary patency were 27.6%, 56.4%, and 66.6%, respectively. Cause-specific 1-year cumulative incidence estimates of unassisted and overall RC-AVF use were 46.8% and 66.9%, respectively. Patients with larger baseline cephalic vein diameters had improved primary (per mm, hazard ratio [HR] 0.89, 95% confidence intervals 0.81–0.99), primary-assisted (HR 0.75, 0.64–0.87), and secondary (HR 0.67, 0.57–0.80) patency; and higher rates of unassisted (subdistribution hazard ratio 1.21, 95% confidence intervals 1.02–1.44) and overall RCAVF use (subdistribution hazard ratio 1.26, 1.11–1.45). Similarly, patients not requiring HD at the time of RCAVF creation had better primary, primary-assisted, and secondary patency. Successful RCAVF use occurred at increased rates when accesses were created using regional anesthesia and at higher volume centers.Conclusions:These insights can inform patient counseling and guide shared decision-making regarding HD access options when developing an individualized end-stage kidney disease life-plan.

Effect of Radiocephalic Anastomotic Length on the Maturation of Arteriovenous Fistula

A radiocephalic arteriovenous fistula (RCAVF) is associated with better long-term patency and fewer complications. However, RCAVF have lower maturation rate for hemodialysis compared with upper AVF or arteriovenous graft. We performed this study to determine the effect of the radiocephalic (RC) anastomotic length on the AVF maturation. We reviewed the patients who underwent RCAVF creation with a side-to-end manner from March 2015 to December 2018. AVF maturation was defined as successful hemodialysis (HD) in at least two consecutive sessions. We compared the possible factors including the RC anastomotic length between the initial HD success group and initial HD failure group. A total of 114 patients underwent RCAVF creation: 72 males and 42 females (63.2% and 36.8%, respectively). The mean preoperative arteriotomy length of the AVF was 14.1 mm (range 11.0-16.0 mm). Out of 114 patients, initial HD was executed successfully in 83 patients (72.8%). Among the 31 patients with initial HD failure (27.2%) balloon angioplasty was successfully performed in 17 patients, failed in 4 patients, and not performed in 10 patients. The secondary success rate after balloon angioplasty was 87.7%. After factor analysis, pre-emptive AVF (P=0.01), vein diameter (P < 0.001), and flow rate (P < 0.001) were revealed significant factors for initial HD success, but not RC anastomotic length of AVF (P=0.55). The length of the radiocephalic anastomosis does not affect the RCAVF maturation rate statistically. However, lengthening of arteriotomy on the radial artery may increase the initial success rate of HD.

MO777HISTOLOGICAL AND IMMUNOPHENOTYPICAL VESSEL CHANGES IN CHRONIC KIDNEY DISEASE

Abstract Background and Aims Recent studies suggest thw possibility of activating immune mechanism in the onset and progression of atherosclerotic disease. The aim of the present study was to evaluate the role of immune mechanisms in the vessel of patients with Chronic Kidney Disease (CKD) and the association with clinical and laboratory indicators of atherosclerosis. Method Patients with CKD stage V, in whom a radiocephalic arteriovenous fistula (RC-AVF) was created, were included in the study. Patients were divided in two groups, group A was consisted of patients who were on stage V, pre-dialysis, and being prepared to start on hemodialysis (HD), and those who had already been on HD for at least 3 years, and were having a new RC-AVF formation, due to previous failure, group B. Inclusion criteria were: age 25-80 years, gradual deterioration of renal function up to stage V or under dialysis for more than 3 years. All patients should have been under close follow up for at least 3 years prior to enrolment, with adequate control of diabetes, hypertension, dyslipidemia, secondary hyperparathyroidism and anemia. The control group included healthy volunteers of similar age, sex and ethnicity, who agreed to have a radial artery biopsy during an orthopedic procedure because of a fracture. All patients were informed and signed the consent form. Patients’ history, primary disease and comorbid conditions, medication and clinical examination were recorded based on hospital outpatients’ files. Prior to the scheduled day of RC-AVF creation, all patients underwent laboratory examination, included hematological and serum biochemical analyses. The histological characteristics, inflammatory activation and immunophenotypic alterations of the radial artery wall were estimated and their association with the severity of calcification and atherosclerosis were studied. Presence and severity of atherosclerotic lesions in CKD patients was assessed based on the measurement of common carotid intima – media thickness (IMT) of the common and internal carotid on both sides. Results Significant correlation was fount between inflammatory infiltration [expression of CD3(+), CD20(+), CD68(+) cells], cellular activation [CD34(+), a-SMA(+) cells] and calcification regulators (MPG, RANKL, OPG) with the degree of vascular calcification, as this was estimated and classified based on Verhoff’s Elastic and von Kossa staining Forty five patients with chronic kidney disease (CKD), stage V, either pre-dialysis (p=25) (group A) or on hemodialysis (HD) (p=20) (group B) were included in the study. There were no significant differences in age, sex, race, and also in the frequency of hypertension, diabetes mellitus or smoking habits between patients and controls. Presence and severity of atherosclerotic lesions in CKD patients was assessed based on the measurement of common carotid intima – media thickness (IMT) of the common and internal carotid on both sides. Conclusion Atherosclerotic disease in Chronic KidnEy Disease and its clinical effects appear to be directly related to inflammatory ifiltration of blood vessels by T, B lymphocytes, macrophages and myofibrolasts, as well as factors that affect calcification.

MO773THE VASCULAR REALITY BEHIND ULTRASOUND VASCULAR MAPPING: WHICH FACTORS PREDICT THE BEST CANDIDATES FOR RADIOCEPHALIC ARTERIOVENOUS FISTULA?

Abstract Background and Aims Vascular accesses (VA) are key components for efficient hemodialysis. Arteriovenous fistulas (AVF) are recommended over arteriovenous graft (AVG), but deciding the type and location of a VA is challenging. Preoperative vascular mapping before surgical creation of VA, especially trough ultrasound (US), is helpful in this decision, contributing to improve AVF e AVG outcomes. Our study aims to identify patient factors associated with appropriate arterial US parameters that predict feasibility for radiocephalic fistula creation. Method We analyzed a cohort of chronic kidney disease patients who underwent US vascular mapping for preoperative planning of dialysis access from 2019 to 2020, in a tertiary referral center. Patients were characterized based on its demographical characteristics, and the presence of diabetes, hypertension, obesity, and smoking. Arterial indicators were analyzed by ultrasound techniques in both upper arms, including radial, ulnar and brachial arteries. Those indicators included arterial diameter, calcification, doppler wave form, and pulse wave velocity. Continuous variables were recorded as means (±SD) for normally distributed data and as medians (interquartile ranges) for nonnormally distributed data. Comparisons were made using t tests or Wilcoxon rank sum tests as appropriate. Categorical variables were examined by frequency distribution and recorded as proportions. Comparisons were made using the x2 test. Unadjusted and adjusted multivariate logistic regression models were fitted to identify predictors for a good candidate for radiocephalic arteriovenous fistula. Results A total of 252 patients were included. The mean age was 65±16 years, 144 (57%) were male, 211 (84%) where white, 40 (16%) were black, and 1 (0.4%) was asian. Most had arterial hypertension (205, 81%), 98 (39%) had diabetes mellitus, 89 (35%) were smokers, and 72 (29%) were obese. The majority of patients were attending for the first VA (186; 74%). Most patients were considered appropriate candidates for arteriovenous fistula creation (207, 82%), whereas 45 (18%) were assigned to PTFE graft. Obesity and male sex were found to be predictors for being a good candidate for radiocephalic arteriovenous fistula in a multivariate logistic regression model adjusted for age, hypertension, and diabetes (OR 3.21, CI 95% 1.63-6.32, p-value 0.001 and OR 2.09, CI 95% 1.07-4.08, p-value 0.031, respectively). Figure 1 presents the arterial indicators analyzed during ultrasound mapping, including both upper limbs. Conclusion Our results show that obesity and male sex are predictors for radiocephalic arteriovenous fistula creation. While female sex has long been known to be a risk factor for VA failure, possibly because of worse arterial indicators, an association between obesity and higher probability of distal AVF creation has not been established yet. Comparison between arterial indicators in obese and nonobese patients shows that obese patients generally have better arterial indicators, especially higher pulse wave velocities, and less arterial calcification. Given that some studies show an association between obesity and shorter fistula survival (due to higher secondary failure rate), our results may come as. A possible explanation for this difference is that obesity may exert a physical protective effect of the forearm vascular bed against iatrogenic damage (blood sampling and vessel cannulation). Besides that, factors other than vascular indicators may contribute to ulterior VA failure, like the proinflammatory state in obese patients and its consequent myointimal hyperplasia. However, our conclusions are based on preoperative findings, and not on VA outcomes, especially its patency and complications. Moreover, which further help to determine the better location for a VA creation, were not evaluated in this study.

Statins Protect against Thrombosis of Cannulated Radiocephalic Fistulas in Diabetic Patients

Radiocephalic arteriovenous fistula (RCAVF) creation is the preferred first line hemodialysis access procedure. Analysis of diabetic rat arteriovenous fistula model indicates improved vascular function with HMG-CoA-Reductase Inhibitor (statin) use. We predict similar outcomes in diabetic patients undergoing primary RCAVF placement. A Veterans Administration Hospital dialysis access database over a fifteen-year period was queried identifying all RCAVF placements in diabetic patients. Patients were stratified into statin medication usage or not at RCAVF creation. Outcomes examined include rate of successful cannulation, functional patency duration, interventions per access, and rates of access thrombosis. Thrombosis-free survival of cannulated RCAVFs were compared using Kaplan-Meier method with log-rank analysis followed by univariate, stepwise logistic regression and ROC curve analysis. Total number of 123 RCAVF cases were performed in 122 diabetic male patients. At the time of RCAVF placement, 92 cases were performed on patients that were taking statin medication and 31 cases were performed on patients that were not taking statin medication. There was no difference in terms of rate of successful cannulation, functional patency duration, and number of interventions per access between the statin and non-statin groups. However, rate of RCAVF thrombosis once accessed was significantly lower in the statin group compared to the non-statin group (p=0.0005). Kaplan-Meier survival curve for each group were compared using log-rank test to reveal that diabetic patients who were on statin therapy at the time of operation had significantly higher access survival over time against thrombosis once it was cannulated for dialysis treatment compared to those who were not on statin therapy (p=0.0003). Univariate, stepwise logistic regression model indicated statin use as the only significant factor associated with lack of thrombosis (p=0.05). Statins appear to have protective effects against RCAVF thrombosis as predicted in animal models for diabetic patients undergoing primary RCAVF placements. There were similar functional outcomes in terms of rate of successful cannulation, functional patency duration, and number of interventions per access. These data should encourage further investigation of statins and their role in hemodialysis access.

Determination of early adaptive flow and diameter changes following creation of radiocephalic arteriovenous fistula for hemodialysis

article: Determination of early adaptive flow and diameter changes following creation of radiocephalic arteriovenous fistula for hemodialysis - Chirurgia 2021 February;34(1):21-4 - Minerva Medica - Journals

PATENCY-2 trial of vonapanitase to promote radiocephalic fistula use for hemodialysis and secondary patency.

Arteriovenous fistulas created for hemodialysis often fail to become usable and are frequently abandoned. This prospective trial evaluated the efficacy of vonapanitase, a recombinant human elastase, in increasing radiocephalic fistula use for hemodialysis and secondary patency. PATENCY-2 was a randomized, double-blind, placebo-controlled trial in patients on or approaching the need for hemodialysis undergoing radiocephalic arteriovenous fistula creation. Of 696 screened, 613 were randomized, and 603 were treated (vonapanitase n = 405, placebo n = 208). The study drug solution was applied topically to the artery and vein for 10 min immediately after fistula creation. The primary endpoints were fistula use for hemodialysis and secondary patency (fistula survival without abandonment). Other efficacy endpoints included unassisted fistula use for hemodialysis, primary unassisted patency, fistula maturation and unassisted maturation by ultrasound criteria, and fistula procedure rates. The proportions of patients with fistula use for hemodialysis was similar between groups, 70% vonapanitase and 65% placebo, (p = 0.33). The Kaplan-Meier estimates of 12-month secondary patency were 78% (95% confidence interval [CI], 73-82) for vonapanitase and 76% (95% CI, 70-82) for placebo (p = 0.93). The proportions with unassisted fistula use for hemodialysis were 46% vonapanitase and 37% placebo (p = 0.054). The Kaplan-Meier estimates of 12-month primary unassisted patency were 50% (95% CI, 44-55) for vonapanitase and 43% (95% CI, 35-50) for placebo (p = 0.18). There were no differences in the proportion of patients with fistula maturation or in fistula procedure rates. Adverse events were similar between groups. Vonapanitase was not immunogenic. Vonapanitase treatment did not achieve clinical or statistical significance to meaningfully improve radiocephalic fistula surgical outcomes. Outcome in the placebo group were better than in historical controls. Vonapanitase was well-tolerated and safe. clinicaltrials.gov: NCT02414841 (https://clinicaltrials.gov/ct2/show/NCT02414841).

Prognostic factors for radiocephalic arteriovenous fistula maturation in patients with prior placement of a central venous catheter and relationship with inflammation

Aim: A mature and functional arteriovenous fistula (AVF) is considered the best modality for vascular access(VA) for hemodialysis (HD) treatment but the incidence of early failure is high, especially in patients start their HD with a central venous catheter. The aim of this study was to evaluate the prognostic value and association of certain patient characteristics and specific inflammatory markers with early failure of AVF in patients who started their HD therapy with a CVC and a first autogenous radiocephalic AVF (RCAVF) was created after vascular consultation. Material and Methods: A retrospective review of 168 patients with end-stage renal disease who underwent RCAVF creation by the same surgeon by using the same surgical technique and whose primary vascular access for HD treatment was obtained via CVC at the time of access consultation was performed. The patients enrolled into this study were categorized into two groups as Group 1: patients with early failure (n=46) and Group 2: patients with no failure (n=122).Demographic characteristics, medical comorbidities, preoperative doppler ultrasound mapping results, laboratory parameters, postoperative follow-up details of these patients were collected. Primary patency of all patients, early failure rate, maturation failure rate, duration of CVC was calculated. Results: Female gender was found to be a significant risk factor in early failure of RCAVF (69.5% vs 36.1%; p=0.001). The number of patients whose diameter of cephalic vein&amp;lt; 2 mm were significantly higher in EF group (78.3% vs 22.1 ; p=0.028). The duration of CVC access of group 1 was significantly longer than group 2 (6.8 ± 3.6 months vs 2.3 ± 1.7 months, respectively; p&amp;lt;0.05). Overall maturation failure rate was 12.5% and primary patency at 1 year was 72.6%. Levels of C-Reactive protein (7.2 ± 9.6 vs 3.1 ± 3.3 mg/L, respectively; p=0.001) and neutrophil lymphocyte ratio (2.91± 0.30 vs 2.17 ± 0.22, respectively; p&amp;lt;0.05) was significantly lower at group 2 at one year. Conclusion:In patients whose VA for HD treatment was provided by CVC, small cephalic vein diameter, female gender and systemic inflammation may play a role in early failure of RCAVF.

Predictors of Primary Functional Maturation of Autogenous Radiocephalic Arteriovenous Fistula in a Cohort of Asian Patients

The aim of this study was to investigate the predictors of autogenous radiocephalic arteriovenous fistula (RCAVF) maturation. This was a retrospective analysis of patients undergoing RCAVF creation from June 2013 to December 2018 at a single medical center. Comparison of the variables between the matured and nonmatured group was performed. A total of 277 patients (men, 173; 62.5%) with a mean age of 56.6±16.9years underwent primary RCAVF creation during the study period. The mean diameter of the cephalic vein and radial artery were 2.4±0.6mm (range 1.5 to 4.3mm) and 2.3±0.5mm (range 1.5 to 4.0mm), respectively. Primary functional maturation was achieved in 236 patients (236/277, 85%). There was no statistical significance between the matured and nonmatured group in terms of age (56.4±14.8 vs. 58.1±15.1, respectively; P=0.498), coronary arterial disease (12% vs. 17%, respectively; P=0.449), diabetes mellitus (42% vs. 39%, respectively; P=0.864), smoking (26% vs. 22%, respectively; P=0.699), or antiplatelet therapy (23% vs. 24%, respectively; P=0.844). However, female gender (35% vs. 54%, respectively; P=0.024), peripheral arterial disease (9% vs. 22%, respectively; P=0.025), and small vein (2.4±0.5mm vs. 2.0±0.5mm, respectively; P<0.01) and artery (2.4±0.5 vs. 2.1±0.4, respectively; P<0.01) diameter were associated with the failure of maturation. The best cutoff diameter for the cephalic vein and radial artery was 1.85mm and 2.05mm, respectively. In this cohort of patients undergoing RCAVF creation, vein and artery diameter on preoperative ultrasound mapping was the predictor of functional maturation. Female gender and presence of peripheral arterial disease were associated with failure of maturation.

The utility of venous bifurcation for anastomosis with small-caliber veins in distal forearm radiocephalic arteriovenous fistula: Retrospective analysis of 52 fistula cases

Context: Distal forearm radiocephalic (RC) arteriovenous fistula (AVF) is the gold standard for vascular access for hemodialysis. The use of venous bifurcation to facilitate anastomoses in small-caliber vessels is well known in microvascular surgery. Small-caliber cephalic vein (CV) is frequently encountered during AVF creation in the distal forearm. We present here the utility of this technique for the creation of distal RC AVF in small-caliber CVs. Objective: The objective was to assess the utility of venous bifurcation for distal forearm RC AVF creation in small-caliber CV. Methodology: Fifty-two cases with CV diameter