Forearm Arteriovenous Fistula Research Articles

#2143 Unveiling key factors on arteriovenous fistulas maturation—a prospective observational study

Abstract Background and Aims The incidence of patients starting haemodialysis is increasing. While Arteriovenous Fistula (AVF) stands as the preferred vascular access method, a significant proportion of AVFs experience primary failure, with rates ranging from 20% to 65%. Moreover, around 50% require reintervention due to delayed maturation, resulting in increased costs and patient morbidity. Understanding the factors involved and their influence on AVF development is paramount. This analysis aims to improve the preoperative decision-making process, advocating for a personalized patient approach, thereby increasing the likelihood of success. Method A prospective observational cohort study that included patients with chronic kidney disease either on dialysis or in the pre-dialysis stage. The study enrolled a total of 140 patients attending a multidisciplinary team appointment (including a vascular surgeon and a nephrologist) at a Tertiary Hospital Centre during the first semester of 2023, of whom 98 patients were included. Demographic characteristics, comorbidities, and vascular parameters observed through ultrasound underwent a comprehensive analysis. The newly formed fistulas were then thoroughly reassessed for maturation using both physical and ultrasound examinations. Results The cohort comprised 56.1% male, with a mean age of 71.06 ± 12.51 years. Among the newly formed fistulas, there were 35.7% (n = 35) radiocephalic fistulas, 46.9% (n = 46) brachiocephalic fistulas, and 17.3% (n = 17) brachiobasilic fistulas. Out of the total 98 AVFs, 59.2% (n = 58) AVFs were maturate and 11.22% (n = 11) AVFs had delayed maturation and were proposed for surgery or angiography procedure. Primary failure occurred in 29.6% (n = 29) AVF, with 42.9% (n = 15) occurring in the forearm, and 22.2% (n = 14) in the upper arm. The major cause of primary failure was thrombosis, accounting for 93.1% (n = 27) of cases. The analysis unveiled that the absence of immediate post-operative thrill, forearm AVFs and previous fistula failure were associated with a higher likelihood of AVF primary failure and non-maturation. Conversely, a larger vein diameter was linked with a reduced likelihood of AVF primary failure, with a Youden Index-derived cut-off of 4.25 mm, with 40.9% sensitivity and 86.2% specificity (p < 0.05). No other clinical or ultrasound factors exhibited a statistically significant impact. Conclusion This study sheds light on the challenges faced in AVF maturation due to a high incidence of primary fistula failure and a maturation rate that only slightly surpasses 50%. A larger vein diameter emerges as a significant predictor of AVF maturation. Although the cut-off point for vein diameter is frequently cited as 2 mm, this value often varies in the literature. This study underscores the importance of considering higher vein diameters, but, more importantly, it suggests that establishing a rigid and uniform cut-off for all centres may not be beneficial. It is crucial to recognize that the optimal vascular characteristics may vary based on the unique circumstances of each centre and the specific needs and features of each patient. The lack of association between demographic parameters and comorbidities with primary failure, juxtaposed with the evidence of more susceptible patients to consecutive primary failure, underscores the need for further studies to explore the unique individual circumstances that may account for this phenomenon.

Application of a supporting catheter in surgery for forearm arteriovenous fistula construction.

This study explored the feasibility of a supporting catheter combined with modified end-to-side anastomosis in the operation of radio-cephalic arteriovenous fistula (RC-AVF) and evaluated the clinical application value of this technique. Sixty patients underwent RC-AVF operations in our hospital from January 2022 to June 2022. All the patients were treated with modified end-to-side AVF anastomosis and divided into the control group or the test group depending on whether a supporting catheter was applied. The clinical data of 60 cases were analysed retrospectively. Intraoperative related indices, the first time the fistula was used, the success rate of first puncture, the blood flow of first dialysis, the maturity condition of fistula, the size of anastomosis, the diameter of radial artery and drainage vein, the blood flow of brachial artery 8 weeks after operation and the incidence of complications within 6 months after operation were compared between the two groups. Compared with that in the control group, the time spent on the vascular anastomosis in the test group was significantly shortened (p<0.05). The blood flow of the first dialysis, the size of the anastomosis, the diameter of the drainage vein, the blood flow of the brachial artery 8 weeks after the operation and the incidence of complications within 6 months after operation were significantly different between the two groups (p<0.05). In the RC-AVF operation, using a supporting catheter can not only increase operation efficiency by reducing surgical injury and difficulty of vascular anastomosis, but also improve postoperative prognosis. RC-AVF is worth promoting in clinical practice.

Impact of stage-specific limb function exercises guided by a self-management education model on arteriovenous fistula maturation status.

The exercise of limb function is the most economical and safe method to promote the maturation of arteriovenous fistula (AVF). However, due to the lack of a unified exercise standard in China, many patients have insufficient awareness of the importance of AVF, leading to poor effectiveness of limb function exercise. The self-management education model can effectively promote patients to take proactive health-related actions. This study focuses on the characteristics of patients during the peri-AVF period and conducts a phased limb function exercise under the guidance of the self-management education model to observe changes in factors such as the maturity of AVF. To assess the impact of stage-specific limb function exercises, directed by a self-management education model, on the maturation status of AVFs. This study is a randomized controlled trial involving 74 patients with forearm AVFs from the Nephrology Department of a tertiary hospital in Sichuan Province, China. Patients were randomly divided into an observation group and a control group using a random number table method. The observation group underwent tailored stage-specific limb function exercises, informed by a self-management education model which took into account the unique features of AVF at various stages, in conjunction with routine care. Conversely, the control group was given standard limb function exercises along with routine care. The assessment involves the maturity of AVFs post-intervention, postoperative complications, and the self-management level of the fistula in both groups patients. Analyses were conducted using SPSS version 23.0. Count data were represented by frequency and percentage and subjected to chi-square test comparisons. Measurement data adhering to a normal distribution were presented as mean ± SD. The independent samples t-test was utilized for inter-group comparisons, while the paired t-test was used for intra-group comparisons. For measurement data not fitting a normal distribution, the median and interquartile range were presented and analyzed using the Wilcoxon rank sum test. At the 8-wk postoperative mark, the observation group demonstrated significantly higher scores in AVF symptom recognition, symptom prevention, and self-management compared to the control group (P < 0.05). However, the variance in symptom management scores between the observation and control groups lacked statistical significance (P > 0.05). At 4 wk after the operation, the observation group displayed a superior vessel diameter and depth from the skin of the drainage vessels in comparison to the control group (P < 0.05). While the observation group did manifest elevated blood flow rates in the drainage vessels relative to the control group, this distinction was not statistically significant (P > 0.05). By the 8-wk postoperative interval, the observation group outperformed the control group with notable enhancements in blood flow rates, vessel diameter, and depth from the skin of drainage vessels (P < 0.01). Seven days following the procedure, the observation group manifested significantly diminished limb swelling and an overall reduced complication rate in contrast to the control group (P < 0.05). The evaluation of infection, thrombosis, embolism, arterial aneurysm stenosis, and incision bleeding showed no notable differences between the two groups (P > 0.05). By the 4-wk postoperative juncture, complications between the observation and control groups were statistically indistinguishable (P > 0.05). Stage-specific limb function exercises, under the guidance of a self-management education model, amplify the capacity of AVF patients to discern and prevent symptoms. Additionally, they expedite AVF maturation and mitigate postoperative limb edema, underscoring their efficacy as a valuable method for the care and upkeep of AVF in hemodialysis patients.

Snuffbox distal transradial access (dTRA) for arteriovenous fistuloplasty in Singapore: Going distal is safe.

Arteriovenous fistula (AVF) dysfunction resulting from stenosis or occlusion, is a prevalent issue in end-stage renal failure patients reliant on autogenous AVFs for dialysis. Recently, a distal transradial approach (dTRA) has emerged, offering advantages such as diminished access site complications, better patient comfort and reduced risk of radial artery occlusion. Our study seeks to assess the effectiveness, outcomes and complication rates of employing dTRA for arteriovenous fistuloplasty in Singaporean patients. A retrospective review of all dTRA fistuloplasties performed on dysfunctional or slow to mature AVFs from 2017 to 2023 in our institution was performed. Patients with a distal radial artery measuring 2 mm or more with no evidence of occlusion or thrombosis were included. Patients who required central venoplasty or cutting balloon angioplasty were excluded. Outcome measures included technical success, mean procedure duration, complications and post-intervention primary patency at 1, 3 and 6 months. Patients were followed up for 12 months post-intervention. A total of 37 patients were included. 97.3% of patients undergoing dTRA fistuloplasty had radiocephalic fistulas while 2.7% had brachiobasilic fistulas. There was 100% technical success (defined as success in radial artery cannulation, sheath insertion and crossing of stenotic lesions) in our study as all patients successfully underwent fistuloplasty via dTRA approach. One-month patency rate was 97.4%, 3-month patency rate was 92.1% and 6-month patency rate was 86.8%. There were no immediate complications (haematoma, infection, bleeding, pseudoaneurysm, occlusion) of the radial artery post-intervention. Our paper illustrates the safety and efficacy of utilising dTRA for arteriovenous fistuloplasty. This approach offers distinct benefits in addressing non-mature or dysfunctional distal forearm arteriovenous fistulas and should be taken into account in anatomically suitable cases.

Distal Forearm Arteriovenous Fistula Maturation in Diabetic Hemodialysis Patients.

Atherosclerotic disease of the forearm arteries can impede the maturation of distal fistulas in diabetic patients. The goal of this study was to look at the maturity of diabetic hemodialysis patients' distal forearm (radiocephalic snuffbox or distal forearm) arteriovenous fistulas. Patients with chronic renal failure who were candidates for distal forearm radiocephalic arteriovenous fistula implantation were evaluated in this cross-sectional study. Patients' demographic details, underlying disorders, laboratory measurements, vital signs, and information on their surgery were all noted. Patients were checked for fistula development 1 week, 1 month, 2months, and then monthly until 6 months after surgery. Arteriovenous fistula maturation characterized by optimal blood flow, vessel dilation, and structural adaptations. Among 343 patients (56% male, 44% female, mean age: 57.32 ± 12.48years), hypertension prevailed (81.9%), followed by hyperlipidemia (42.3%) and coronary artery disease history (25.9%). AVFs achieved 58.3% maturation in 64.98 ± 11.05days; higher BP during creation correlated with successful maturation (17.02 ± 1.46mmHg vs 13.90 ± 1.93mmHg, P < .05). No significant statistical difference found in distal forearm arteriovenous fistula maturation between males (57.8%) and females (58.9%) (P > .005). However, 41.7% of AVFs failed in 18.83 ± 17.89days. Failed AVFs exhibited lower BP during operation and failure (11.75 ± 1.86mmHg). Kaplan-Meier analysis depicted maturation probabilities over 90 days post-surgery. Diabetes and patient sex did not affect the maturation time of distal forearm AVFs in hemodialysis patients. Increased blood pressure during and after surgery correlated with shorter maturation time.

Temporal trends in hemodialysis access creation during the fistula first era

ObjectiveAlthough forearm arteriovenous fistulas (AVFs) are the preferred initial vascular access for hemodialysis based on national guidelines, there are no population-level studies evaluating trends in creation of forearm vs upper arm AVFs and arteriovenous grafts (AVGs). The purpose of this study was to report temporal trends in first-time permanent hemodialysis access type, and to assess the effect of national initiatives on rates of AVF placement. MethodsRetrospective cross-sectional study (2012-2022) utilizing the Vascular Quality Initiative database. All patients older than 18 years with creation of first-time upper extremity surgical hemodialysis access were included. Anatomic location of the AVF or AVG (forearm vs upper arm) was defined based on inflow artery, outflow vein, and presumed cannulation zone. Primary analysis examined temporal trends in rates of forearm vs upper arm AVFs and AVGs using time series analyses (modified Mann-Kendall test). Subgroup analyses examined rates of access configuration stratified by age, sex, race, dialysis, and socioeconomic status. Interrupted time series analysis was performed to assess the effect of the 2015 Fistula First Catheter Last initiative on rates of AVFs. ResultsOf the 52,170 accesses, 57.9% were upper arm AVFs, 25.2% were forearm AVFs, 15.4% were upper arm AVGs, and 1.5% were forearm AVGs. From 2012 to 2022, there was no significant change in overall rates of forearm or upper arm AVFs. There was a numerical increase in upper arm AVGs (13.9 to 18.2 per 100; P = .09), whereas forearm AVGs significantly declined (1.8 to 0.7 per 100; P = .02). In subgroup analyses, we observed a decrease in forearm AVFs among men (33.1 to 28.7 per 100; P = .04) and disadvantaged (Area Deprivation Index percentile ≥50) patients (29.0 to 20.7 per 100; P = .04), whereas female (17.2 to 23.1 per 100; P = .03), Black (15.6 to 24.5 per 100; P < .01), elderly (age ≥80 years) (18.7 to 32.5 per 100; P < .01), and disadvantaged (13.6 to 20.5 per 100; P < .01) patients had a significant increase in upper arm AVGs. The Fistula First Catheter Last initiative had no effect on the rate of AVF placement (83.2 to 83.7 per 100; P=.37). ConclusionsDespite national initiatives to promote autogenous vascular access, the rates of first-time AVFs have remained relatively constant, with forearm AVFs only representing one-quarter of all permanent surgical accesses. Furthermore, elderly, Black, female, and disadvantaged patients saw an increase in upper arm AVGs. Further efforts to elucidate factors associated with forearm AVF placement, as well as potential physician, center, and regional variation is warranted.

Analysis of risk factors for late arteriovenous fistula failure and patency rates after angioplasty in hemodialysis patients: a retrospective cohort study.

The incidence of chronic kidney disease (CKD) and end-stage kidney disease (ESKD) is increasing worldwide. Hemodialysis (HD) is the mainstay of renal replacement therapy for patients with ESKD. Risk factors associated with late arteriovenous fistula (AVF) failure in HD patients are poorly investigated. Therefore, the aim of this study was to identify factors associated with late AVF failure in HD patients. Patients with end-stage renal disease (ESRD) who underwent forearm or upper arm AVF angioplasty at Second Affiliated Hospital of Chongqing Medical University between September 2009 and August 2018 were included. Patients were followed up for 36 months. Baseline characteristics were collected using electronic medical records (EMRs). Variables associated with late AVF failure were identified using Cox proportional hazards models. There were 137 patients (64% male, 36% female) included in this study, with 50 (36.5%) experiencing AVF failure. Univariable log-rank analysis showed that age, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), intact parathyroid hormone (iPTH), albumin (ALB), and AVF patency rate were significantly different between patients who did and did not experience AVF failure. Cox regression analysis showed that CRP [P=0.002, hazard ratio (HR) =2.719, 95% confidence interval (CI) for HR: 1.432-5.164], ESR (P=0.030, HR =2.431, 95% CI: 1.088-5.434), iPTH (P=0.013, HR =0.325, 95% CI: 0.133-0.793), and ALB (P=0.040, HR =0.539, 95% CI: 0.299-0.972) were independently associated with AVF failure. Kaplan-Meier survival analysis showed that the cumulative patency rates of AVF at 6, 12, 18, 24, 30, and 36 months were 84%, 74%, 69%, 64%, 64%, and 64%, respectively. CRP, ESR, iPTH, and ALB were associated with AVF failure and should be used as reference in clinical practice.

Distal AVF creation with marginal calcified radial artery: Multicentric experience of intraoperative intravascular lithotripsy.

The first-choice vascular access to starting dialysis in patients with End Stage Renal Disease (ESRD) is autogenous distal arteriovenous-fistula (AVF) to spare vascular district avoiding proximal fistula complications. One of most significant exclusion criteria to create distal AVF is still now the presence of huge calcification of the feeding artery due to large numbers of early failure (EF) and failure in maturation (FTM). In recent years the possibility to use new devices able to deliver intravascular lithotripsy (IVL) to treat high calcified stenosis could be a possibility to recruit these marginal arteries to create distal AVF. ESRD patients with totally calcified radial artery wall were enrolled to participate to this prospective, single arm, multicentric study. The selected patients were treated with intraoperative IVL at surgical time, during anastomosis creation to soften calcified radial artery. Patients were followed 1 month after surgery with eco-doppler, for flow and vessels maturation assessment. At 3 month was investigated how many patients have started dialysis treatment with two needle cannulation and good efficiency. Nineteen distal forearm radio-cephalic fistula were built in 19 patients. One-month doppler assessment showed mean AVF flow of 743 ml/min and efferent vein caliper of 6.46 mm. At 3 months 14 patient have started stable 2 needles dialysis (other three patients were not yet dialysis dependent CKD). Were observed one immediate failure, one failure in maturation, and two late failures at 4 and 16 months respectively. Sixteen months primary and secondary patency was 78.9% and 89.5% respectively. These results showed how intraoperative IVL could help to recruit huge calcified marginal artery to create autogenous distal forearm AVF, avoiding proximal AVF, risking distal ischemia syndrome, and sparing vascular district to eventually rebuilt more proximal AVF in future.

Salvage treatment of forearm arteriovenous fistula with small caliber inflow distal artery by percutaneous transluminal angioplasty

Background: Dysfunctional distal arteriovenous fistulas (AVFs) with small caliber distal inflow arteries theoretically require percutaneous transluminal angioplasty (PTA) throughout the entire arterial length. However, in clinical practice, whole distal inflow arterial PTA is not frequently performed due to concerns about possible arterial rupture. Therefore, we investigated the safety and efficacy of this procedure at our center, comparing it with the standard venous PTA. Methods: From March 2017 to December 2022, 48 cases of distal AVF salvaged by whole distal inflow arterial PTA were assigned into a treatment group and 121 cases of distal AVF salvaged by venous standard PTA not involving the whole inflow artery were assigned into a control group. These two groups were then compared. Results: Those in the treatment group (who received whole distal inflow arterial PTA) were older than those in the control group (mean age, 69 vs 59 years, p &lt; 0.001). Otherwise, differences between the two groups were unremarkable. After the salvage treatment, primary patency seemed to decrease in the treatment group with whole distal inflow arterial PTA compared to the control group with conventional PTA, although such decrease was not significant ( p = 0.072). However, primary assisted patency and secondary patency were comparable between the two groups ( p = 0.350 and p = 0.590, respectively). And in the treatment group, only one arterial dissection occurred, which was successfully managed with balloon tamponade so that no distal AVF was abandoned due to complications following whole distal inflow arterial PTA. Conclusion: Whole distal inflow arterial PTA is an effective and safe option for distal AVF salvage with a narrowed inflow artery, frequently refractory to conventional venous PTA.

Effect of preoperative arterial diameter on hospitalization and mortality in patients undergoing hemodialysis with forearm arteriovenous fistula access.

As pointed out by the recent Kidney Disease Outcomes Quality Initiative Clinical Practice Guideline for Vascular Access, the current quality of evidence supporting preoperative vascular anatomy and patient outcomes is suboptimal and insufficient to make recommendations. This study assessed arteriovenous fistulas (AVFs) created with different preoperative arterial diameters on hospitalization and mortality rates in patients undergoing hemodialysis at the authors' center. Data from 261 patients who underwent HD between 2017 and 2019 were retrospectively examined. Differences in mortality and hospitalization rates between patients with different preoperative arterial diameters were compared, and risk factors for mortality and hospitalization were analyzed. Smaller preoperative artery diameter (<2 mm) was associated with all-cause mortality (risk ratio [RR] 1.61 [95% confidence interval (CI) 1.45-1.90]; p < 0.01), and access-related (RR 1.68 [95% CI 1.24-2.44]; p < 0.01), and congestive heart failure (CHF)-related (RR 0.67 [95% CI 0.38-1.01]; p = 0.04) hospitalization. Longer catheter-dependent duration (⩾60 days) was associated with access-related hospitalization (RR 1.48 [95% CI 1.07-2.11]; p = 0.03), and higher postoperative brachial artery blood flow (⩾1500 mL/min) was associated with CHF-related hospitalization (RR 1.58 [95% CI 1.02-2.29]; p < 0.01). Higher postoperative brachial artery blood flow (⩾1500 mL/min) was associated with all-cause mortality (hazard ratio [HR] 1.20 [95% CI 1.09-2.32]; p = 0.04), whereas preoperative artery diameter (HR 0.98 [95% CI 0.93-1.86]; p = 0.08) and catheter-dependent duration (HR 1.06 [95% CI 0.47-2.13]; p = 0.82) were not associated with all-cause mortality. In this cohort, smaller preoperative artery diameter was associated with all-cause and access-related hospitalizations, while a larger preoperative artery and higher postoperative brachial blood flow were associated with CHF-related hospitalization. However, only higher postoperative brachial blood flow was associated with all-cause mortality.

Guideline recommendations on minimal blood vessel diameters and arteriovenous fistula outcomes.

Clinical guidelines provide recommendations on the minimal blood vessel diameters required for arteriovenous fistula creation but the evidence for these recommendations is limited. We compared vascular access outcomes of fistulas created in agreement with the ESVS Clinical Practice Guidelines (i.e. arteries and veins >2 mm for forearm fistulas and >3 mm for upper arm fistulas) with fistulas created outside these recommendations. The multicenter Shunt Simulation Study cohort contains 211 hemodialysis patients who received a first radiocephalic, brachiocephalic, or brachiobasilic fistula before publication of the ESVS Clinical Practice Guidelines. All patients had preoperative duplex ultrasound measurements according to a standardized protocol. Outcomes included duplex ultrasound findings at 6 weeks after surgery, vascular access function, and intervention rates until 1 year after surgery. In 55% of patients, fistulas were created in agreement with the ESVS Clinical Practice Guidelines recommendations on minimal blood vessel diameters. Concordance with the guideline recommendations was more frequent for forearm fistulas than for upper arm fistulas (65% vs 46%, p = 0.01). In the entire cohort, agreement with the guideline recommendations was not associated with an increased proportion of functional vascular accesses (70% vs 66% for fistulas created within and outside guideline recommendations, respectively; p = 0.61) or with decreased access-related intervention rates (1.45 vs 1.68 per patient-year, p = 0.20). In forearm fistulas, however, only 52% of arteriovenous fistulas created outside these recommendations developed into a timely functional vascular access. Whereas upper arm arteriovenous fistulas with preoperative blood vessel diameters <3 mm had similar vascular access function as fistulas created with larger blood vessels, forearm arteriovenous fistulas with preoperative blood vessel diameters <2 mm had poor clinical outcomes. These results support that clinical decision-making should be guided by an individual approach.

Outflow Rescue of Elbow-Blockade Forearm Arteriovenous Fistulas: Outcomes of Open Surgical Techniques

Venous scarring at the elbow is a common problem that can cause early and late forearm arteriovenous fistula (AVF) dysfunction in hemodialysis patients. However, any effort to prolong the long-term patency of distal vascular accesses could benefit the patient's survival, maximizing the use of restricted venous patrimony. This study aims to report a single-center experience in the recovery of distal autologous AVF with venous outflow obstruction at the elbow using different surgical techniques. Retrospective observational study of all patients treated at a single vascular access center from January 2011 to March 2022, with dysfunctional forearm AVFs presenting with outflow stenosis or occlusions at the elbow treated by open surgery, using 3 different surgical techniques. Demographics and clinically relevant data were collected. Evaluated endpoints included primary, assisted primary, and secondary patency rates at 1 and 2years. Twenty-three patients with elbow-blocked outflow forearm AVFs have been treated with a mean age of 64±15years. The majority (96%) had a radiocephalic fistula. The median time from vascular access creation to intervention was 34.5months (12-216months). A total of 24 procedures have been performed using 3 different surgical techniques for bypassing the obstructed venous outflow at the elbow. Technical success was achieved in 96% of the surgically treated patients. Primary and secondary patency rates at 1year were 67.4% and 89.4%, respectively, and 52.9% and 82.0% at 2years, with a median follow-up of 19months (6-92months). AVFs outflow stenosis or occlusions at the elbow not amenable to endovascular therapy could lead to vascular access abandonment. Our study demonstrates multiple surgical solutions to avoid this adverse outcome. Elbow venous outflow surgical reconstruction seems effective for distal vascular access preservation. Close surveillance is essential for timely endovascular treatment of newly developed stenosis at the venous drainage.

The feasibility of small-caliber veins for autogenous arteriovenous fistula creation: A single-center retrospective study.

Autogenous arteriovenous fistula (AVF) is recommended as the first choice for hemodialysis vascular access. A small-caliber vein is one of the independent risk factors for AVF maturation and patency. However, the specific threshold is still unclear, making it difficult to accurately determine whether these vessels are suitable for AVF creation. This is a single-center retrospective study. Patients who underwent AVF creation in our medical center between January 2020 and September 2022 and satisfied the eligibility criteria were included in this retrospective study. Logistic regression analysis was performed to identify risk factors for functional maturation and additional intervention. The optimal cutoff value was determined based on the receiver operating curve (ROC) and the Youden index. Kaplan-Meier analysis was utilized in further patency rate comparisons. A total of 125 forearm AVFs were created in 121 patients with end-stage renal disease (ESRD). The mean age was 53.88 ± 15.10 years. Preoperative vascular Doppler ultrasound (DUS) was conducted and recorded in 106 cases (84.80%). The mean targeted artery and vein diameters were 2.17 ± 0.54 and 1.71 ± 0.75 mm, respectively. Small-caliber vein is the risk factor for functional maturation failure (OR = 0.256, 95%CI [0.06-0.75], p = 0.033) and additional intervention (OR = 0.306, 95% CI [0.09-0.78], p = 0.031). The optimal cutoff value is 1.35 mm (augmented) when specificity and sensitivity reach 80 and 63.7%, respectively. The AVFs with a vein diameter of more than 1.35 mm (augmented) showed higher patency rates (p < 0.01). After comprehensive DUS evaluation, intraoperative hydrodilation, postoperative active exercise and intensive DUS detection, and application of balloon-assisted maturation, if necessary, using a vein more than 1.35 mm (augmented), could achieve satisfactory functional maturation and postoperative patency in AVF formation.

Optimal Flow Volume Measurements in Forearm versus Arm Arteriovenous Fistulas.

Successful haemodialysis is dependent on optimal arteriovenous (AV) access flow. Although 600 mL/min is frequently quoted as the critical level for functional flow volume (Qa) according to the National Kidney Foundation guideline, this may not be applicable for the different configurations of AV fistulas (AVF) or AV grafts (AVG). This study evaluates ultrasound derived Qa measurement in the inflow brachial artery to autologous AVF in the forearm radiocephalic and arm brachiocephalic/basilic configurations in relation to significant flow related AV dysfunction. Five hundred and eleven duplex ultrasound (DUS) scans were analysed in 193 patients. The end points were therapeutic intervention and/or thrombosis of AVF versus no complication within three months of the scan. Receiver operating characteristic (ROC) curves were used to determine the optimal threshold Qa of the brachial artery supplying the AVF. Of the 511 scans, 155 scans were assigned to the intervention group, ie, AVF requiring intervention or thrombosing within 3 months of the DUS. Using ROC curve analysis, the area under the curve (AUC) for all AVF is 0.90 (CI: 0.88-0.93) with an optimal threshold Qa of 686mL/min. In forearm AVF, the threshold Qa is 589mL/min while in arm AVF the threshold Qa is 877mL/min. Forearm Qa is statistically different from arm Qa. Forearm AVF Qa threshold at 589 mL/min is distinct from arm AVF Qa at 877 mL/min and these are predictive of the need for impending intervention or thrombosis due to flow-limiting stenosis. This article is protected by copyright. All rights reserved.

MICROSURGERY FOR THE CREATION OF ARTERIOVENOUS FISTULAS IN PATIENTS WITH RADIAL ARTERIES DIAMETER SMALLER THAN 1.6 MM

In End-stage Renal Disease patients, the distal forearm is the preferred site for hemodialysis access, however forearm vessels have small diameter and according to Guidelines a radial artery internal diameter smaller than 1.6-2 mm is strongly predictive of early failure of the arteriovenous fistula (AVF) because of stenosis and obstruction. It could happen for some patients to not be considered suitable for distal forearm AVF because of poor peripheral vessels, so in these cases the micrusurgical technique can be very helpful in handling such “inadequates” vessels for lower-arm fistula creation. This study is an investigation of long-term patency of distal radio-cephalic AVFs created under microscopic guidance by using small radial arteries (less the 1.6 mm diameter) in adult patients with chronic renal failure and without severe comorbidities. In a sample of 31 patients, at 1 year postoperatively, the mean primary patency rate was 67.7% (21 functioning AVFs out of 31) and that is quite the same result of AVFs’ made with arteries larger than 2 mm.

Forearm Arteriovenous Fistula Maturation Delay due to Juxta-Anastomotic Stenosis: Role of Percutaneous Angioplasty

Introduction: Arteriovenous fistula is the optimal vascular access for hemodialysis as it has the best long-term patency rate and the lowest complication rate. Although we are still lacking consensus, surgery has been advocated as the best treatment option for maturation delay. We proposed to evaluate the results of endovascular approach of arteriovenous fistula’s maturation delay in our hospital. Methods: We conducted a retrospective study, selecting patients referred to our diagnostic and therapeutic angiography unit due to arteriovenous fistula delayed maturation, between April 2017 and June 2020. Results: Thirty-four patients were referred to our center due to maturation delay, of which six (17.7%) were excluded as the diagnosis was not confirmed and six (17.7%) because the lesions were not suitable for percutaneous angioplasty. The other 22 patients (64.7%) were subjected to percutaneous endovascular treatment. Mean age was 67.3 ± 13.8 years. Eighteen patients (81.8%) had maturation delay due to peri-anastomotic stenosis; 12 (66.7%) were forearm fistulas (all radio-cephalic). Mean follow-up time was 21.2 ± 11.2 months. Eleven (91.7%) fistulas were salvaged, although four (33.3%) needed reintervention. Primary and assisted primary patencies at 6 and 12 months were 66.7% vs 91.7% and 58.3% vs 91.7%, respectively. Conclusion: Our results point out that endovascular treatment is a good treatment option for maturation delay of forearm arteriovenous fistulas due to juxta-anastomotic stenosis. Even though surgical treatment appears to have better primary patency, a step-by-step approach seems to be a valid strategy, as our assisted primary patency shows.

The association between the locations of arteriovenous fistulas and patency rates: A systematic review and meta‐analysis

The arteriovenous fistulas (AVF) continue to be the most prevalent type of vascular access for hemodialysis (HD). However, the appropriate locations of AVF are controversial. We conducted the meta-analysis to investigate the differences in patency between upper-arm and forearm AVF. PubMed, EMBASE, CENTRAL, and ISI Web of Science were searched to identify studies with differences in AVF patency at different locations. Reviewers searched the database, screened studies according to inclusion criteria, and conducted Meta-analysis. A total of 12 studies involving 3437 patients were selected. Pooled data showed that primary patency (PP) of AVF were higher in upper-arm than forearm at 1 and 2 years (odds ratio [OR] = 1.54, p = 0.0005; OR = 2.45, p = 0.001), but the differences in cumulative patency (CP) were not statistically significant at 1 and 2 years (OR = 2.10, p = 0.08; OR = 2.16, p = 0.1). The differences in PP and CP between upper-arm and forearm AVF in patients older than 65 years were not statistically significant at 1 (OR = 1.61, p = 0.05; OR = 2.05, p = 0.17) and 2 years (OR = 3.40, p = 0.13; OR = 1.38, p = 0.16). In Asian patients, the differences in PP and CP between upper-arm and forearm AVF were not statistically significant at 1 (OR = 1.17, p = 0.41; OR = 1.02, p = 0.94) and 2 years (OR = 2.95, p = 0.08; OR = 1.23, p = 0.41). In this study, the CP of upper-arm and forearm AVF was similar in overall population. There was no difference in PP and CP of AVF between upper-arm and forearm in Asian population or the elderly. The forearm AVF could be consider to be the first choice. for Asian patients or the elderly.

Multicenter European real-world utilization of VasQ anastomotic external support device for arteriovenous fistulae.

To evaluate the outcomes of arteriovenous fistulae (AVF), created with VasQ external support device under standard clinical practice across three vascular access clinics. This multinational, retrospective study evaluated prospectively collected clinical outcomes of both forearm and upper arm brachiocephalic AVF (BCAVF) created using the VasQ device. Fifty-one AVF patients were pooled from three different vascular access centers in Germany, Italy, and Spain. Postprocedure outcomes were assessed by flow measurement with ultrasound examination in all centers. Primary failure, usability, patency, and intervention rates during the study period were evaluated. Fifty-one VasQ devices were implanted during 37 forearm (36 radiocephalic and 1 ulnar-basilic AVF) and 14 BCAVF procedures. The study population comprised mostly males (73%) and Caucasians (82%), with a mean age of 62.5years (range, 38-84years) and mean body mass index of 29.2. One patient died owing to access-unrelated reasons, and one patient was lost to follow-up without AVF assessment after its creation. From the remaining 49, 3 patients had a follow-up of less than 4weeks and were excluded from maturation, primary failure, and dialysis initiation analysis (because those factors could not be evaluated yet), leaving 46 patients in this evaluation. Maturation was achieved in 91% of patients. The primary failure rate was 9%. A primary patency rate of 77% was observed at 6, 12, and 18months. The secondary patency rate was 91% at 6months, and 85% at 12months and 18months. Both primary patency and secondary patency did not differ statistically when comparing forearm AVF with BCAVF (P > .25). Successful cannulation was achieved in 86% of patients (32/37) requiring dialysis with a median time from creation to cannulation of 46days. Of those patients, the functional patency rate was 94%. Five patients underwent seven interventions to maintain or restore patency or functionality, with an overall rate of 0.248 interventions per patient-year. AVFs created with VasQ external support device demonstrated promising patency and functionality outcomesin multicentric real-world setting across the two most commonly used anatomic locations.

Routes to Improve Arteriovenous Fistula Formation for Haemodialysis

Background. Contemporary methods to create primary arteriovenous fistula (AVF) for permanent vascular access (PVA) in haemodialysis continue to improve. The modified Brescia-Cimino operation is considered the main technique of forming native AVF. Various early PVA complications occur in 6–40 % patients entailing repeated surgical interventions.Materials and methods. The study was conducted at the vascular surgery unit of City Clinical Hospital No. 21 of Ufa. All patients had surgery for distal AVF formation in forearm. Native forearm AVF creation was aided by the hydraulic balloon dilation technique prior to forming anastomosis.Results. The PVA survival was 75.0 (n = 30), the median survival time corresponding to estimated time-to-rehospitalisation in at least 50 % patients (n = 30) was 4.0 ± 0.89 (95 % CI: 2.25–5.75) months. Mean time-to-relapse was 6.05 ± 1.15 (95 % CI: 3.8–8.3) months.Discussion. The results obtained suggest the accessory hydraulic balloon dilation method useful prior to forming anastomosis to provide for the vein mechanical expansion, outflow capacity assessment and prevent venous torsion at preparation steps. Preparing a certain vein length (10 cm) with ligation of putative tributaries is also of importance.Conclusion. The accessory technique of hydraulic balloon dilation of recipient vein in primary native AVF creation allows an intraoperative estimation of the vein state to exclude torsion and perform its mechanical dilation prior to forming anastomosis, which reduces the risk of postoperative thromboses.

Creating reverse flow arteriovenous fistulas with a forearm cannulation target.

Establishing a forearm arteriovenous fistula (AVF) offers preferred cannulation sites and preserves proximal access opportunities. When a radiocephalic AVF at the wrist is not feasible and the upper arm cephalic and median cubital veins are inadequate, an AV graft or more complex access procedure is often required. Creating a retrograde flow forearm AVF (RF-AVF) is a valuable alternative where the mid-forearm median antebrachial or cephalic vein is adequate, offering forearm cannulation zones with AVF outflow through deep and superficial collaterals. We report our technique and results. We retrospectively reviewed our vascular access data base of consecutive patients during an 11-year study period where a RF-AVF established the only available cannulation target in the forearm. In addition to physical examination, all patients had ultrasound vessel mapping. A forearm access was established with a RF-AVF as the only opportunity for cannulation in 48 patients. Ages were 14-86 years (median = 62 years). Forty-four percent female, 63% diabetic, 13% obese, and 29% had previous access operations. Inflow was proximal radial artery in 47 individuals and one proximal ulnar. Nine AVFs (19%) failed at 2-66 months (median 14 months). One RF-AVF was ligated due to arm edema. Follow-up was 2-111 months (median = 23.5 months). Primary and cumulative patency rates were 62% and 91% at 12 months, and 46% and 85% at 24 months. Five patients were lost to follow-up with functioning RF-AVFs (mean 41 months). Twenty-three patients (48%) died during F/U of causes unrelated to access procedures (mean 25 months). Establishing a reverse flow forearm AVF offers a successful autogenous access option in the forearm for selected patients with an inadequate distal radial artery and/or cephalic vein at the wrist, avoiding more complex or staged procedures and preserving upper arm sites for future use. A proximal radial artery inflow procedure is recommended.