Arteriovenous fistula in dialysis patients: Factors implicated in early and late AVF maturation failure

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

A systematic review of prediction models on arteriovenous fistula: Risk scores and machine learning approaches

OBJECTIVE

Failure-to-mature and early stenosis remains the Achille's heel of hemodialysis arteriovenous fistula (AVF) creation. The maturation and patency of an AVF can be influenced by a variety of demographic, comorbidity, and anatomical factors. This study aims to review the prediction models of AVF maturation and patency with various risk scores and machine learning models.

DATA SOURCES AND REVIEW METHODS

Literature search was performed on PubMed, Scopus, and Embase to identify eligible articles. The quality of the studies was assessed using the Prediction model Risk Of Bias ASsessment (PROBAST) Tool. The performance (discrimination and calibration) of the included studies were extracted.

RESULTS

Fourteen studies (seven studies used risk score approaches; seven studies used machine learning approaches) were included in the review. Among them, 12 studies were rated as high or unclear "risk of bias." Six studies were rated as high concern or unclear for "applicability." C-statistics (Model discrimination metric) was reported in five studies using risk score approach (0.70-0.886) and three utilized machine learning methods (0.80-0.85). Model calibration was reported in three studies. Failure-to-mature risk score developed by one of the studies has been externally validated in three different patient populations, however the model discrimination degraded significantly (C-statistics: 0.519-0.53).

CONCLUSION

The performance of existing predictive models for AVF maturation/patency is underreported. They showed satisfactory performance in their own study population. However, there was high risk of bias in methodology used to build some of the models. The reviewed models also lack external validation or had reduced performance in external cohort.

Rejoining Veins for Forced Maturation of Small-Caliber Arteriovenous Fistula

BACKGROUND

To evaluate the efficacy of rejoining mainstream and accessory veins for forced maturation of autogenous arteriovenous fistula (AVF).

METHODS

Twenty-three patients who underwent forced maturation through vein rejoining between January 2018 and September 2022 were included. In cases where AVF maturation failure due to the presence of accessory veins, rejoining was primarily considered when distinguishing the main branch becomes challenging. This difficulty typically occurs when the sizes of the 2 vessels are nearly equal and the combined diameters of these veins exceed 6 mm.

RESULTS

The mean age and follow-up duration were 57.39 ± 16.22 years and 965.65 ± 573.42 days, respectively. Rejoining of both arterial and venous cannulation sites was performed in 11 patients (47.8%), and rejoining of only the venous cannulation site or only the arterial cannulation site was performed in 11 patients (47.8%) and 1 patient (4.3%), respectively. The mean vein size was 0.35 ± 0.06 cm before rejoining and 0.69 ± 0.07 cm after surgery, indicating a significant increase in size (P < 0.01), whereas the flow did not change significantly following rejoining surgery. Maturation and cannulation success was 100%. The 1-year primary patency rate after surgery was 82.0%. During the follow-up period, 34.8% of the patients required additional percutaneous transluminal angioplasty to maintain patency, and 2 patients (11.8%) had stenosis in the rejoined section.

CONCLUSIONS

Rejoining surgery is an effective method for achieving AVF maturation in patients with accessory veins when identification of the mainstream vein is difficult, and this method may be considered when achieving maturation by sacrificing 1 vein is expected to be challenging.

Short-term mortality and revisions to promote maturation after arteriovenous fistula creation

OBJECTIVE

Arteriovenous fistula (AVF) for hemodialysis access is traditionally considered superior to grafts due to infection resistance and purported improved patency. However, challenges to AVF maturation and limited patient survival may reduce AVF benefits. The objective of this study is to identify factors associated with risk of AVF requiring revision before maturation and/or mortality within 2 years of creation.

METHODS

We performed a retrospective review of 250 AVFs created between May 2017 and November 2020 at a single institution. Maturation was defined as the date the surgeon deemed the AVF ready for use or the patient successfully used the AVF for dialysis. The Risk Analysis Index was used to calculate frailty. The primary outcome was a composite of endovascular/surgical revision to promote maturation and/or mortality within 2 years of AVF creation (REVDEAD). The primary outcome was categorized as met if the patient required a revision to promote maturation or if the patient experienced mortality within 2 years of AVF creation, or if both occurred. REVDEAD was compared with those who did not meet the primary outcome and will be referred to as NOREVDEAD.

RESULTS

Survival at 2 years after AVF creation was 82%, and 54 (22%) patients underwent AVF revision. Of those, 31 (59%) patients progressed to AVF maturation. Of the 250 AVFs, 91 (36%) met the primary outcome of REVDEAD and 159 (64%) did not (NOREVDEAD). There was no difference between the REVDEAD and NOREVDEAD groups in age (P = .18), sex (P = .75), White race (P = .97), Hispanic ethnicity (P = .62), obesity (P = .76), coronary artery disease (P = .07), congestive heart failure (P = .29), diabetes mellitus (P = .78), chronic obstructive pulmonary disease (P = .10), dialysis status (P = .63), hypertension (P = .32), peripheral arterial disease (P = .34), or dysrhythmia (P = .13). There was no difference between the groups in the forearm vs the upper arm location of AVF (P = .42) or the vein diameter (P = .58). Forearm access, as opposed to upper arm AVF creation, was associated with higher rate of revision before maturation (P = .05). More patients in REVDEAD were frail or very frail (60% vs 48%, P = .05). Of the AVFs that matured, maturation required longer time in REVDEAD at 110.0 ± 9.1 days vs 78.8 ± 5.6 days (mean ± standard deviation) (P = .003). Adjusted for the vein diameter and the forearm vs the upper arm, frailty increased the odds of REVDEAD by 1.9 (95% confidence interval: 1.1, 3.3).

CONCLUSIONS

Frail patients who underwent AVF were significantly more likely to die within 2 years of AVF creation with no significant association between frailty and the need for revisions to promote maturation. Forearm AVFs were more likely to require revisions; in patients who are frail, with a high likelihood of 2-year mortality, graft may be more appropriate than AVF. If AVF is being considered in a frail patient, upper arm AVFs should be prioritized over forearm AVFs.

Percutaneous ecoguided endovascular lithotripsy to recruit failed-to-mature arteriovenous fistula due to completely calcified radial artery

The first-choice vascular access for starting dialysis is autogenous distal forearm arteriovenous-fistula (AVF); the increasing demand to create more fistulas may lead to their creation in borderline vessels and, in this setting, the early failure (EF) and failure of maturation (FTM) remain the main issues. The size of vessels or preexisting stenotic lesions of artery or vein are no longer considered absolute exclusion criteria for the creation of distal AVF, but huge arterial calcification still represents an indication to create upper arm AVF. A novel approach to treat arterial calcifications is represented by intravascular lithotripsy (IVL). This technique could represent a valid option to save failed to mature AVF due to extended calcified artery. We describe a case of a male patient, 43 years old with middle forearm AVF failed to mature with a completely calcified radial artery, low brachial flow (Qa) and small efferent vein. We treated the patient AVF with less invasive, percutaneous, endovascular, eco-guided IVL on the entire radial artery. After the procedure was observed a rapid increase of Qa, with reduction of calcification in the arterial wall, increase of arterial caliper and flow. This procedure could represent a valid alternative to surgical upper-arm AVF creation in patient with functioning but failed to mature fistula due to spread artery calcification, with a rapid, less invasive procedure.

Effectiveness of a native vein arteriovenous fistula tracking system

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Small Arteriovenous Anastomosis in Fistula Creation: Establishing a Functional Vascular Access while Minimizing Steal Syndrome

BACKGROUND

The size selection of the arteriovenous (AV) anastomosis in dialysis access creation requires a careful balance: the diameter must be large enough to accommodate sufficient flow for hemodialysis but small enough to minimize the complication of steal syndrome. Steal syndrome affects up to 10% of patients after creation of dialysis access with sometimes devastating consequences. Conventional teaching recommends a 7-10 mm anastomosis. We sought to assess the efficacy of using a smaller (5-6 mm) anastomosis in new arteriovenous fistula (AVF) creation.

METHODS

We conducted a comparative retrospective analysis of patients who underwent fistula creation with a small versus regular size anastomosis at any upper extremity anatomic site between March 2019 and October 2020 at our institution. Anatomic sites included radiocephalic, brachiocephalic, and brachiobasilic. All AV anastomoses were measured intraoperatively to be 5-6 mm in diameter for the small size groups and 8-10 mm for the regular size group. Endpoints included steal syndrome, functional patency, primary patency, and secondary patency.

RESULTS

Out of 110 patients who underwent an AVF creation, 59.1% received a 5-6 mm anastomosis with a median follow-up time of 10 ± 6 months. Patients' demographics and comorbidities were relatively similar between the 2 groups except for a higher rate of hyperlipidemia (55.4% vs. 28.9%, P = 0.008) in the small size group. Patients in the small size group were more likely to undergo a radiocephalic fistula (40% vs. 4.5%, P < 0.001) and to have a smaller mean vein diameter on preoperative duplex ultrasound (3.2±1 mm vs. 3.9±1 mm, P = 0.0016) when compared to their regular size counterparts. During follow-up, none of the patients in the small group developed steal syndrome (0% vs. 9%, P = 0.015). At 1 year, patients in the regular size group achieved higher rates of primary patency (67.9% vs. 46.9%, P = 0.02); however, no difference was seen in 1-year primary-assisted patency (84.9% vs. 73.6%, P = 0.3), secondary patency (89.6% vs. 79.5%, P = 0.3), or functional patency (87.7% vs. 82.2%, P = 0.64) between the small and regular size groups, respectively.

CONCLUSIONS

The use of a 5-6 mm anastomosis in the creation of new AVFs of the upper extremities appears to be a technically safe option for dialysis access. Our experience suggests that smaller anastomosis still creates enough flow to maintain a functional AV access while minimizing the incidence of steal syndrome. Additionally, even with smaller vein sizes preoperative, adequate dialysis access can be created via a small sized anastomosis, including distal arm access. Larger studies with longer follow-up are needed to evaluate long-term outcomes of small anastomosis fistulas.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Early arteriovenous fistula failure associated with mortality and major adverse cardiovascular events in patients undergoing incident hemodialysis

BACKGROUND

Arteriovenous fistula (AVF) patency is important for patients undergoing hemodialysis. The association between early AVF failure and the prognosis, including all-cause mortality and major adverse cardiovascular events (MACE), has not been fully investigated. The present study was performed to investigate the association between early AVF failure and 3-year mortality, cardiovascular disease (CVD) mortality, and MACE.

METHODS

We analyzed 358 patients who started hemodialysis in our institution from October 2008 to February 2020. We defined early AVF failure as cases requiring percutaneous transluminal angioplasty or reoperation within 1 year after AVF surgery. The patients were divided into two groups according to the presence or absence of early AVF failure, and the prognosis of each group was examined. The association between early AVF failure and outcomes (3-year all-cause mortality, CVD mortality, and MACE) was determined using Cox proportional hazards regression analysis.

RESULTS

During the 3-year follow-up, 75 (20.9%) patients died (cardiovascular death: n = 39) and 145 patients developed MACE. According to the multivariable analysis, the early AVF failure group had a significantly higher risk of 3-year all-cause mortality (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.09-1.83; p = 0.009), CVD mortality (HR, 1.54; 95% CI, 1.29-2.08; p < 0.001), and MACE (HR, 1.68; 95% CI, 1.25-2.26; p < 0.001). When the patients were stratified by age, early AVF failure was associated with 3-year all-cause mortality in all groups except for the younger group (<65 years of age).

CONCLUSIONS

Early AVF failure was associated with an increased risk of 3-year all-cause mortality, CVD mortality, and MACE.

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.

Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

A Case Report of a Successful Attempt to Create a Hemodialysis Vascular Access in a Patient With Recurrent Failed Arteriovenous Fistulas

The majority of individuals undergoing hemodialysis for chronic renal insufficiency (CRI) require vascular access. The more appropriate and long-term accesses are arteriovenous fistulas (AVF). These accesses must be attempted to be salvaged even in the circumstances when they stop functioning. In this study, a case report of a 57-year-old female patient with CRI who presented with a failed brachioradial and brachiocephalic AVF in the left upper limb and who later underwent the creation of a new functional radio-cephalic AVF mid-arm on the same limb is presented.

Preoperative assessment for vascular access: Vascular mapping and handgrip strength

BACKGROUND

Reliable vascular access (VA) is required for patients receiving chronic hemodialysis (HD) treatment. Vascular mapping using duplex doppler ultrasonography (DUS) can aid in planning VA construction. Greater handgrip strength (HGS) was found to be associated with more developed distal vessels both in chronic kidney disease (CKD) patients and healthy individuals, and patients with lower HGS had worse morphologic vessel characteristics and were, therefore, less likely to construct distal VA.

OBJECTIVES

This study aims to describe and analyze clinical, anthropometric, and laboratory characteristics of patients who underwent vascular mapping prior to VA creation.

RESEARCH DESIGN

Prospective analysis.

SUBJECTS

Adult patients with CKD referred for vascular mapping, at a tertiary center, between March 2021 and August 2021.

MEASURES

Preoperative DUS by a single experienced nephrologist was carried out. HGS was measured using a hand dynamometer, and PAD was defined as ABI < 0.9. Sub-groups were analyzed according to distal vasculature size (<2 mm).

RESULTS

A total of 80 patients were included, with a mean age of 65.7 ± 14.7 years; 67.5% were male, and 51.3% were on renal replacement therapy (RRT). Twelve (15%) participants had PAD. HGS was higher in the dominant arm (20.5 ± 12.0 vs 18.8 ± 11.2 kg). Fifty-eight (72.5%) patients had vessels smaller than 2 mm in diameter. There were no significant differences between groups concerning demographics or comorbidities (diabetes, HTN, PAD). HGS was significantly higher in patients with distal vasculature greater than or equal to 2 mm in diameter (dominant arm: 26.1 ± 15.5 vs 18.4 ± 9.7 kg, p = 0.010; non-dominant arm: 24.1 ± 15.3 vs 16.8 ± 8.6, p = 0.008).

CONCLUSIONS

Higher HGS was associated with more developed distal cephalic vein and radial artery. Low HGS might be an indirect sign of suboptimal vascular characteristics, which might help predict the outcomes of VA creation and maturation.

Long-term efficacy and risk factors of balloon-assisted maturation for radial-cephalic arteriovenous fistula with small-caliber veins

INTRODUCTION

Balloon angioplasty maturation (BAM) is a salvage method for autologous arteriovenous fistula (AVF) maturation failure. AVF creation using small-diameter veins is considered to have poor outcomes. Therefore, this study aimed to explore the long-term patency of small-diameter veins (≤3 mm) using BAM.

METHODS

BAM was performed if the fistula failed to mature and function adequately to provide prescribed dialysis.

FINDINGS

Out of 61 AVFs, 22 AVFs successfully matured without further intervention (AVF group) and 39 AVFs failed to mature. Except for 1 patient who required peritoneal dialysis, the remaining 38 patients received salvage BAM, and 36 of those successful matured (BAM group). Kaplan-Meier analysis revealed no significant differences between the AVF and BAM groups in terms of primary functional patency (p = 0.503) and assisted functional patency (p = 0.499). Compared with the AVF group, the BAM group had similar assisted primary functional patency (1-year: 94.7% vs. 93.1%; 3-year: 88.0% vs. 93.1%; 5-year: 79.2% vs. 88.3%). In addition, there were no significant difference between groups in the duration of primary functional patency and assisted primary functional patency (p > 0.05). Multivariate analyses showed that vein diameter and number of BAM procedures were independent predictors of primary functional patency in the AVF group and BAM group, respectively. Patient with 1 mm increase in vein size had 0.13-fold probability of having decreased duration of patency (HR = 0.13, 95% CI: 0.02-0.99, p = 0.049), while patients who received two times of BAM procedures were 2.885 as likely to have decreased duration of primary functional patency (HR = 2.885, 95% CI: 1.09-7.63, p = 0.033) than patients who received one BAM procedure.

DISCUSSION

BAM is a relatively effective salvage management option with an acceptable long-term patency rate, even for small cephalic veins.

Patency Rates and Outcomes of Renal Access Arteriovenous Fistulas for Hemodialysis in Patients with Chronic Kidney Disease

Hemodialysis remains the most popular modality of renal replacement therapy for end-stage renal disease patients with chronic kidney disease. Various factors such as a radial artery, cephalic vein diameter, age, hypertension, and diabetes mellitus can affect the fistula maturation. This study was carried out to know the patency rates and factors affecting fistula maturation in the Indian population. This is a prospective observational study which aimed to study the patency rate of arteriovenous (AV) fistulas. On the day of surgery, patients were shifted inside the operation theater. Under all aseptic precautions, an AV fistula was formed using the radial artery and cephalic vein. All patients were followed up for 6 months. The data were analyzed using IBM SPSS version 22. To see the change over a period of time, McNemar test for categorical data and repeated measure for continuous data followed by post hoc comparison by Bonferroni method were used. The mean age of the patients was 46.98 ± 13.33 years. The mean diameter of the cephalic vein, ulnar artery, and radial artery at the wrist was 1.733 ± 0.528, 1.700 ± 0.364, and 1.908 ± 0.420, respectively, whereas the mean diameter of the cephalic vein, ulnar artery, and radial artery at the forearm was 1.952 ± 0.488, 1.910 ± 0.421, and 2.058 ± 0.458, respectively. Immediate thrill after the surgery was present in 36/52 (69.2%) of the patients. The radial artery diameter at the wrist was significantly less in the patients with primary failure in whom immediate thrill was not present (P = 0.016). At 1-month follow-up, 30/49 (61.2%) and, at 6 months, 29/48 (60.4%) fistulas were functional. Radiocephalic AV fistulas have a reasonable success rate and minimal morbidity, and radial artery diameter is a good predictor of the outcome.

Arteriovenous fistula creation by nephrologist and its outcomes: a prospective cohort study from Vietnam

BACKGROUND

Arteriovenous fistula (AVF) is the gold standard vascular access for effective hemodialysis. There is a growing interest in AVF creations performed by nephrologists to help reduce vascular surgeons' workload and enhance the timely treatment of patients with end-stage renal disease (ESRD). However, little is known about the feasibility and effectiveness of this approach in the low-resource settings. We examined the AVF surgical success and failure rates and associated predictors as well as early complications of AVF creations by a trained nephrologist with supports from vascular surgeons in Vietnam.

METHODS

A prospective cohort study was conducted on all adult ESRD patients at the Hemodialysis Department of Thong Nhat Hospital between April 2018 and October 2020. Information on demographic characteristics, comorbidities, and AVF creations was collected using a standardized questionnaire. All patients were followed up until 18 weeks post-surgery.

RESULTS

Among 100 patients with a mean age of 61.22 ± 17.11 years old, male accounted for 54%. Common causes of ESRD included hypertension (57%) and diabetes (32%). Just more than half (52%) of them reported having an AVF creation prior to ESRD. The successful first-time AVF creation rate was 98% (13/99, 95%CI: 8.74-21.18%). The primary and secondary AVF failure rates were 13.13% (13/99, 95%CI: 8.74-21.18%) and 16.87% (14/83, 95%CI: 10.32-26.25%), respectively. Early complications included bleeding (1%) and early thrombosis of the anastomosis (2%). There was a statistically significant association between age and primary AVF failure (P = 0.005) and between operation time and secondary AVF failure (P = 0.038).

CONCLUSIONS

AVF creations performed by well-trained and skilled interventional nephrologists with supports from vascular surgeons can result in favorable short- and long-term outcomes. It is important to follow up older patients and those with a long operation time to detect AVF failures. A standardized AVF creation training program and practice for nephrologists is needed to increase successful rates.

Bundle of Care Promotes Arteriovenous Fistula Maturity in Patients with End-Stage Kidney Disease

BACKGROUND

Arteriovenous fistula (AVF), as the hemodialysis access, has the advantages of safety, sufficient blood flow, and long use time. To establish an ideal AVF, patients require good vascular condition. However, many teams often neglect preoperative preparation and exercises and have no concept of specialized nursing or bundle of care, directly leading to stenosis of the outflow tract and seriously affected surgical efficacy. This study aimed to evaluate the influence of bundle of care on AVF.

METHODS

A total of 260 patients with end-stage kidney disease were included from January 2019 to December 2020 at Qilu Hospital, Shandong University. Patients were divided into 2 groups, and were treated with ordinary nursing care (the control group) or bundle of care (the observation group). Maturity of AVF fistula and postoperative complications were compared between 2 groups.

RESULTS

The observation group was associated with larger internal diameter of the cephalic vein (6.524 ± 0.347 vs. 6.346 ± 0.32 4 mm) and faster blood flow at the anastomosis of AVF (568.2 ± 26.8 vs. 565.7 ± 27.5 mL/min) than the control group at 2 weeks after surgery (both P < 0.05). The observation group had a higher maturity rate than the control group (93.1% vs. 81.5%, P < 0.05) at 8 weeks after surgery. There were lower incidences of fistula stenosis (4.6% vs. 10.8%) and fistula thrombosis (2.3% vs. 7.7%) in the observation group than in the control group (both P < 0.05). The secondary patency was higher in the observation group than in the control group (97.7% vs. 92.3%, P < 0.05).

CONCLUSIONS

The use of bundle of care promotes AVF maturity and reduces postoperative complications in patients with end-stage kidney disease.

Does the balloon-assisted maturation procedure offer comparable results for AVF created with a smaller vein?

BACKGROUND

Traditionally, a venous diameter of less than 3 mm was not considered for creation of AVF. Some studies have reported smaller venous size could be used for operation. AVF created with a smaller vein may have a lower maturation rate. Currently, percutaneous angioplasty is also used to enhance the maturation of AVF. This study aimed to establish whether the BAM procedure could offer comparable results for AVF created with a smaller vein.

METHODS

From January 2016 to July 2021, 290 patients who received native AVF operation were enrolled in this study. All of the preoperative venous sizes were measured by Duplex ultrasonography under tourniquet enhancement. The study cohort was categorized into two groups based on the pre-operative venous diameter: smaller vein group (SVG, 2.5 < size < 3 mm, 53.1%) and normal vein group (NVG, size ⩾ 3 mm, 46.9%).

RESULTS

The mean age was 64 ± 12.9 years, and 58.6% of patients were male. Hypertension and DM were the most common comorbidities. Most patients underwent operation of radio-cephalic fistula (71.4%). The overall primary maturation rate was 79%. The primary maturation rate was significantly higher in the NVG (86% vs 72.7%, p = 0.009). However, after the BAM procedure, the secondary maturation rate was similar in both groups (94.1% vs 90.3%, p = 0.319).

CONCLUSIONS

According to our study, the BAM procedure can significantly increase the maturation rate, and the secondary maturation rate was similar in both groups. Thus, more patients can be given the opportunity to undergo creation of an AVF for long-term hemodialysis.

Luminal pressure gradient and risk of arteriovenous fistula nonmaturation

While arteriovenous fistula (AVF) nonmaturation is a major issue of hemodialysis care, an effective treatment to improve AVF maturation remains lacking. AVF introduces pulsatile arterial blood flow into its venous limb and produces high luminal pressure gradient, which may have adverse effect on vascular remodeling. As such, the aim of the present study is to investigate effect of luminal pressure gradient on AVF nonmaturation. This single-center, prospective observational study includes patients receiving autologous AVF creation. Participants received early postoperative ultrasound 5-7 days after surgery to collect parameters including diameters, flow rates, and volume at inflow and outflow sites. Luminal pressure gradient was estimated by using modified Bernoulli equation. The outcome was spontaneous AVF maturation within 8 weeks after surgery without intervention. Thirty patients were included, of which the mean age was 66.9 years and 70% were male. At the end of study, 13 (43.3%) patients had spontaneous AVF maturation. All demographic and laboratory characteristics were similar between patients with mature and nonmature AVF. Regarding ultrasonographic parameters, nonmature AVF showed significantly higher inflow/outflow diameter ratio, inflow velocity, and luminal pressure gradient. While these 3 parameters were significantly correlated, multivariate logistic regression showed their significant association with AVF nonmaturation. Receiver operating characteristic curve exhibited their high predictive value for AVF nonmaturation. Our findings showed that higher inflow/outflow ratio, inflow velocity, and AVF luminal pressure gradient in early postoperative ultrasound predicted risk of AVF nonmaturation. Reducing inflow/outflow diameter ratio or inflow rate may be an approach to improve AVF maturation. The predictive value of this early assessment might have impact on the clinical practice of AVF care.

Localized Perivascular Therapeutic Approaches to Inhibit Venous Neointimal Hyperplasia in Arteriovenous Fistula Access for Hemodialysis Use

An arteriovenous fistula (AVF) is the preferred vascular access for chronic hemodialysis, but high failure rates restrict its use. Optimizing patients' perioperative status and the surgical technique, among other methods for preventing primary AVF failure, continue to fall short in lowering failure rates in clinical practice. One of the predominant causes of AVF failure is neointimal hyperplasia (NIH), a process that results from the synergistic effects of inflammation, hypoxia, and hemodynamic shear stress on vascular tissue. Although several systemic therapies have aimed at suppressing NIH, none has shown a clear benefit towards this goal. Localized therapeutic approaches may improve rates of AVF maturation by providing direct structural and functional support to the maturating fistula, as well as by delivering higher doses of pharmacologic agents while avoiding the adverse effects associated with systemic administration of therapeutic agents. Novel materials-such as polymeric scaffolds and nanoparticles-have enabled the development of different perivascular therapies, such as supportive mechanical devices, targeted drug delivery, and cell-based therapeutics. In this review, we summarize various perivascular therapeutic approaches, available data on their effectiveness, and the outlook for localized therapies targeting NIH in the setting of AVF for hemodialysis use. Highlights: Most systemic therapies do not improve AVF patency outcomes; therefore, localized therapeutic approaches may be beneficial. Locally delivered drugs and medical devices may improve AVF patency outcomes by providing biological and mechanical support. Cell-based therapies have shown promise in suppressing NIH by delivering a more extensive array of bioactive substances in response to the biochemical changes in the AVF microenvironment.

Oxidative stress: An essential factor in the process of arteriovenous fistula failure

For more than half a century, arteriovenous fistula (AVFs) has been recognized as a lifeline for patients requiring hemodialysis (HD). With its higher long-term patency rate and lower probability of complications, AVF is strongly recommended by guidelines in different areas as the first choice for vascular access for HD patients, and its proportion of application is gradually increasing. Despite technological improvements and advances in the standards of postoperative care, many deficiencies are still encountered in the use of AVF related to its high incidence of failure due to unsuccessful maturation to adequately support HD and the development of neointimal hyperplasia (NIH), which narrows the AVF lumen. AVF failure is linked to the activation and migration of vascular cells and the remodeling of the extracellular matrix, where complex interactions between cytokines, adhesion molecules, and inflammatory mediators lead to poor adaptive remodeling. Oxidative stress also plays a vital role in AVF failure, and a growing amount of data suggest a link between AVF failure and oxidative stress. In this review, we summarize the present understanding of the pathophysiology of AVF failure. Furthermore, we focus on the relation between oxidative stress and AVF dysfunction. Finally, we discuss potential therapies for addressing AVF failure based on targeting oxidative stress.

Preoperative Cardiac Index as a Predictor of Maturation and Primary Patency of Radiocephalic Arteriovenous Fistula in Hemodialysis

BACKGROUND

Radiocephalic arteriovenous fistula (RCAVF) is the best access modality to be considered initially when planning arteriovenous fistula (AVF) for maintenance hemodialysis. Considering the higher incidence of RCAVF failed maturation (M), it is important to perform proper preoperative evaluation and identification of high-risk patients. There has been no study on the influence of preoperative cardiac function on the M and patency of AVFs. The purpose of this investigation is to determine whether preoperative cardiac index (CI) is a predictor of M and primary patency of RCAVF.

METHOD

A total of 365 end-stage renal disease patients undergoing RCAVF surgery were consecutively enrolled with a median follow-up time of 20 months in this prospective cohort study. Demographics, vascular diameters measured by duplex ultrasound examination, and CI measured by echocardiography, were analyzed for effect on RCAVF primary functional M and primary patency.

RESULT

Patients in the group achieving primary RCAVF functional M had a significantly larger mean CI than the group with early RCAVF failure (2.93 ± 0.77 vs. 3.57 ± 0.76 L/min/m2, p < 0.001). The receiver operating characteristic curve was plotted and demonstrated that preoperative vein diameter and CI can predict failure of RCAVF M. The AUC of CI was higher (0.745 vs. 0.666). Multivariate regression analysis, adjusted for age, sex, diabetes, preoperative dialysis status and vessel diameters, showed that decreased CI remained associated with increased risk of failure of M (FM) and worse primary unassisted patency. The Kaplan-Meier survival analysis suggested that patients with CI <3 L/min/m2 had a worse primary unassisted patency rate at all time points compared with patients with CI ≥3 L/min/m2.

CONCLUSION

This study demonstrated that preoperative CI was associated with RCAVF M and long-term patency. A decreased CI may be a possible predictor of an increased risk of FM and a shorter primary patency time.

Venous outflow banding for maturation of a percutaneous arteriovenous fistula

In the present report, we have described venous outflow banding as a technique to assist with maturation of a percutaneous arteriovenous fistula (pAVF) without sacrificing potential target veins for future access. A 47-year-old obese man had undergone pAVF creation between the right ulnar vessels with coil embolization of the brachial vein. Follow-up imaging demonstrated the median cubital vein briskly filling the cephalic and basilic veins. The basilic vein was banded with the patient under local anesthesia successfully. Banding of the superficial veins provides an alternative after creation of a pAVF to preserve veins that could be used as conduits for future access.

Bridge of Tunneled Cuffed Catheter as a Risk for Future Arteriovenous Fistulae Failure

Background: A clinically tunneled cuffed catheter (TCC) for hemodialysis (HD) is often inserted into end-stage renal disease patients, who have an immature or no arteriovenous fistula (AVF), for the performance of HD to relieve uremic syndrome or to solve uncontrolled fluid overload, hyperkalemia, or metabolic acidosis. The catheter is primarily regarded as a bridge until the AVF matures and can be cannulated for HD. However, the effect of the bridge of the TCC on the future patency of AVFs remains elusive. Methods: This nationwide population-based observational study compared the hazards of AVF failure and the time to AVF failure. We enrolled 24,142 adult incident patients on HD, who received HD via AVFs for at least 90 days between 1 January 2010 and 31 December 2015. The subjects were divided into two groups, according to the history of TCC, and were followed-up until the failure of the AVF, mortality, or the end of the study. A propensity score-matched analysis based on 1:1 matching of age, sex, and baseline comorbidities was utilized to reduce bias and confounding variables. Results: A Kaplan−Meier survival curve revealed that patients with and without a history of TCC had significantly better AVF survival rates (log-rank test; p < 0.001). A history of TCC was independently associated with a higher risk of new AVF or AVG creation due to AVF failure, after the adjustment of the Charlson comorbidity index score (corresponding adjusted hazard ratios of 2.17 and 1.52; 95% confidence intervals of 1.77−2.67 and 1.15−1.99). For the impact of time on AVF failure, patients with a TCC bridge had a significantly higher incidence of new AVF creation during the first year after the AVF cannulation. Conclusion: A history of a TCC bridge was an independent risk factor for AVF failure and the time of AVF failure was significantly higher during the first year after the fistula cannulation in the TCC bridge group.

Outcomes of Arteriovenous Fistula Creation in Patients Undergoing Hemodialysis: An Indian Experience

Introduction

Creating an arteriovenous fistula (AVF) to provide a patent and long-term vascular access (VA) for hemodialysis (HD) still remains a challenge. A methodical approach to choosing the appropriate HD access in accordance with patients’ end-stage kidney disease (ESKD) life plan will help them achieve their goals safely. This study summarizes the impact of various factors on the AVF outcomes in an Indian population as well as the necessary considerations before choosing the site of AVF creation.

Materials and methods

This study involved a single-center, retrospective evaluation of all patients who had undergone arteriovenous (AV) access creation for maintenance HD from October 2018 to August 2019 at a center in India.

Results

In our study of 216 cases, the average age at presentation was 43.9 years and the difference in age between the successful and unsuccessful group was not significant. The successful outcomes in males were significantly higher than those in females (p=0.005). The mean venous diameter in the successful group was significantly larger than that in the unsuccessful group. The distal arterial and vein diameter was higher in both males and females of the laborer group compared to the clerical group; however, the outcomes were comparable. The overall complication rate was 22.22%. We had primary patency rates of 83% at the end of one year with a primary failure rate of 8.80%.

Conclusion

Vein diameter was the most important predictive factor for a successful outcome in our study. Factors like age and life expectancy, gender, comorbidities, occupation, and type of anastomosis may not be individually predictive of outcomes but need to be considered before choosing the appropriate site of access creation according to the life plan of the patient. This will reduce morbidity associated with an additional procedure and facilitate the initiation of HD as early as possible. Occupation can be considered as a surrogate for preoperative forearm exercises with the increased caliber of vessels found in people performing heavy/manual labor favoring a more distal AVF creation.

Aorta in Pathologies May Function as an Immune Organ by Upregulating Secretomes for Immune and Vascular Cell Activation, Differentiation and Trans-Differentiation-Early Secretomes may Serve as Drivers for Trained Immunity

To determine whether aorta becomes immune organ in pathologies, we performed transcriptomic analyses of six types of secretomic genes (SGs) in aorta and vascular cells and made the following findings: 1) 53.7% out of 21,306 human protein genes are classified into six secretomes, namely, canonical, caspase 1, caspase 4, exosome, Weibel-Palade body, and autophagy; 2) Atherosclerosis (AS), chronic kidney disease (CKD) and abdominal aortic aneurysm (AAA) modulate six secretomes in aortas; and Middle East Respiratory Syndrome Coronavirus (MERS-CoV, COVID-19 homologous) infected endothelial cells (ECs) and angiotensin-II (Ang-II) treated vascular smooth muscle cells (VSMCs) modulate six secretomes; 3) AS aortas upregulate T and B cell immune SGs; CKD aortas upregulate SGs for cardiac hypertrophy, and hepatic fibrosis; and AAA aorta upregulate SGs for neuromuscular signaling and protein catabolism; 4) Ang-II induced AAA, canonical, caspase 4, and exosome SGs have two expression peaks of high (day 7)-low (day 14)-high (day 28) patterns; 5) Elastase induced AAA aortas have more inflammatory/immune pathways than that of Ang-II induced AAA aortas; 6) Most disease-upregulated cytokines in aorta may be secreted via canonical and exosome secretomes; 7) Canonical and caspase 1 SGs play roles at early MERS-CoV infected ECs whereas caspase 4 and exosome SGs play roles in late/chronic phases; and the early upregulated canonical and caspase 1 SGs may function as drivers for trained immunity (innate immune memory); 8) Venous ECs from arteriovenous fistula (AVF) upregulate SGs in five secretomes; and 9) Increased some of 101 trained immunity genes and decreased trained tolerance regulator IRG1 participate in upregulations of SGs in atherosclerotic, Ang-II induced AAA and CKD aortas, and MERS-CoV infected ECs, but less in SGs upregulated in AVF ECs. IL-1 family cytokines, HIF1α, SET7 and mTOR, ROS regulators NRF2 and NOX2 partially regulate trained immunity genes; and NRF2 plays roles in downregulating SGs more than that of NOX2 in upregulating SGs. These results provide novel insights on the roles of aorta as immune organ in upregulating secretomes and driving immune and vascular cell differentiations in COVID-19, cardiovascular diseases, inflammations, transplantations, autoimmune diseases and cancers.

A single-centre, retrospective analysis of mortality over 80 months comparing paclitaxel-coated balloon versus standard balloon angioplasty in the treatment of dysfunctional arteriovenous access

AIM

Percutaneous transluminal angioplasty (PTA) is a standard treatment for arteriovenous fistula (AVF) stenosis to preserve haemodialysis vascular access, promoting improved dialysis adequacy and better outcomes for those dependent on renal replacement therapy. Drug coated balloons (DCB) may help reduce the rate of neointimal hyperplasia and recurrent stenosis, but their use in femoropopliteal angioplasty has been associated with increased mortality at 2 and 5 year follow-up. This study aims to address the long-term safety of PTA for AVF stenosis with clinical correlation to participant co-morbidity and mortality.

METHODS

All patients undergoing PTA for AVF stenosis at a single centre between 2013 and 2017 were identified and grouped according to the use of DCB versus standard balloon angioplasty. All data was anonymised and correlated to verify independent predictors of mortality.

RESULTS

481 (400 standard balloon; 81 DCB) procedures were performed in 313 patients (250 standard balloon; 63 DCB). Follow-up at 80 months did not show any difference in mortality (p = 0.546). Multivariate analysis identified time on dialysis (p < 0.001), age (p = 0.001) and Charlson comorbidity index (p = 0.02) as independent predictors of mortality.

CONCLUSIONS

In this study, mortality was not associated with the use of DCBs, but was related to established factors of dialysis longevity, age and comorbidity.

Early cannulation versus standard arteriovenous grafts in hemodialysis patients: a randomized clinical study

OBJECTIVE

Arteriovenous grafts (AVGs) are frequently needed in hemodialysis (HD) patients with unsuitable superficial veins. First cannulation of standard arteriovenous grafts (sAVGs) still require about 2 weeks after implantation. Early cannulation arteriovenous grafts (eAVGs) were suggested to overcome this shortcoming. The present randomized study proposed to compare the clinical outcomes of sAVGs and eAVGs in HD patients.

METHODS

The present single-center randomized clinical study recruited 477 HD patients indicated for AVG creation. They included 236 in the sAVG group and 241 in the eAVG group. Eligible patients were simply randomized and allocated to the studied groups using 1:1 allocation ratio. Blinding was secured using the sealed envelope technique. Enrolled patients were followed up for 12 months. The primary outcome in the present study was primary, primary assisted, and secondary patency rates at 12 months. Other outcome parameters included time to first cannulation, graft complications, and mortality.

RESULTS

Comparison between the studied groups regarding the primary outcomes revealed no statistically significant differences. Primary patency rate was 65.7% and 68.0% (P = .58) at 6 months and 53.8% and 56.4% (P = .57) at 12 months in the sAVG and eAVG groups, respectively. Primary assisted patency rate was 70.8% and 69.7% (P = .8) in patients with sAVG and eAVG, whereas the reported rates at 12 months were 59.3% and 61.0% (P = .71), respectively. Secondary patency rate was 78.4% and 73.9% (P = .25) at 6 months and 67.8% and 69.7% (P = .65) at 12 months in the sAVG and eAVG groups, respectively. As expected, patients in the eAVG group experienced significantly earlier cannulation when compared with patients in the sAVG group (median, 3.0 days; range, 1.0-9.0 days vs 19.0 days; range, 15.0-22.0 days; P < .001).

CONCLUSIONS

Patients in the eAVG group have comparable outcomes to those in the sAVG group at 12 months with the added advantage of earlier time to first cannulation.

Effect of far infrared therapy on arteriovenous fistula maturation, survival and stenosis in hemodialysis patients, a randomized, controlled clinical trial: the FAITH on fistula trial

BACKGROUND

An arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis treatment. After creation many of the AVFs will never mature or if functioning will need an intervention within 1 year due to an AVF stenosis. Studies investigating possible therapies that improves the AVF maturation and survival are scarce. Far infrared therapy (FIR) has shown promising results. In minor single centre and industry supported trials FIR has shown improved AVF maturation and survival. There is a need of a randomized multicentre controlled trial to examine the effect of FIR on the AVF maturation and survival and to explore the possible AVF protective mechanism induced by the FIR treatment.

METHODS

This investigator initiated, randomized, controlled, open-labeled, multicenter clinical trial will examine the effect of FIR on AVF maturation in patients with a newly created AVF (incident) and AVF patency rate after 1 year of treatment in patients with an existing AVF (prevalent) compared to a control group. The intervention group will receive FIR to the skin above their AVF three times a week for 1 year. The control group will be observed without any treatment. The primary outcome for incident AVFs is the time from surgically creation of the AVF to successful cannulation. The primary outcome for the prevalent AVFs is the difference in number of AVFs without intervention and still functioning in the treatment and control group after 12 months. Furthermore, the acute changes in inflammatory and vasodilating factors during FIR will be explored. Arterial stiffness as a marker of long term AVF patency will also be examined.

DISCUSSION

FIR is a promising new treatment modality that may potentially lead to improved AVF maturation and survival. This randomized controlled open-labelled trial will investigate the effect of FIR and its possible mechanisms.

TRIAL REGISTRATION

Clinicaltrialsgov NCT04011072 (7th of July 2019).

Medical adjuvant treatment to increase patency of arteriovenous fistulae and grafts

BACKGROUND

People with end-stage renal disease (ESRD) often require either the formation of an arteriovenous fistula (AVF) or an interposition prosthetic arteriovenous graft (AVG) for haemodialysis. These access sites should ideally have a long life and a low rate of complications (e.g. thrombosis, infection, stenosis, aneurysm formation and distal limb ischaemia). Although some of the complications may be unavoidable, any adjuvant technique or medical treatment aimed at decreasing complications would be welcome. This is the fourth update of the review first published in 2003.

OBJECTIVES

To assess the effects of adjuvant drug treatment in people with ESRD on haemodialysis via autologous AVFs or prosthetic interposition AVGs.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and ClinicalTrials.gov trials register to 6 August 2020.

SELECTION CRITERIA

Randomised controlled trials of active drug versus placebo in people with ESRD undergoing haemodialysis via an AVF or prosthetic interposition AVG.

DATA COLLECTION AND ANALYSIS

For this update, two review authors (IM, MFAK) independently selected trials for inclusion, extracted data, assessed risk of bias and assessed the certainty of the evidence according to GRADE. We resolved disagreements by discussion or consultation with another review author (ADS). The primary outcome was the long-term fistula or graft patency rate. Secondary outcomes included duration of hospital stay; complications such as infection, aneurysm formation, stenosis and distal limb ischaemia; and number of related surgical or radiological interventions.

MAIN RESULTS

For this update, one additional study was suitable for inclusion, making a total of 13 trials with 2080 participants. Overall the certainty of the evidence was low or moderate due to short follow-up periods, heterogeneity between trials, small sample sizes, and risk of bias due to incomplete reporting. Medical adjuvant treatments used in the included trials were aspirin, ticlopidine, dipyridamole, dipyridamole plus aspirin, warfarin, fish oil, clopidogrel, sulphinpyrazone and glyceryl trinitrate (GTN) patch.  All included studies reported on graft patency by measuring graft thrombosis. There was insufficient evidence to determine if there was a difference in graft patency in studies comparing aspirin versus placebo (odds ratio (OR) 0.40, 95% confidence interval (CI) 0.07 to 2.25; 3 studies, 175 participants; low-certainty evidence). The meta-analysis for graft patency comparing ticlopidine versus placebo favoured ticlopidine (OR 0.45, 95% CI 0.25 to 0.82; 3 studies, 339 participants; moderate-certainty evidence). There was insufficient evidence to determine if there was a difference in graft patency in studies comparing fish oil versus placebo (OR 0.24, 95% CI 0.03 to 1.95; 2 studies, 220 participants; low-certainty evidence); and studies comparing clopidogrel and placebo (OR 0.40, 95% CI 0.13 to 1.19; 2 studies, 959 participants; moderate-certainty evidence). Similarly, there was insufficient evidence to determine if there was a difference in graft patency comparing the effect of dipyridamole versus placebo (OR 0.46, 95% CI 0.11 to 1.94; 1 study, 42 participants, moderate-certainty evidence) and dipyridamole plus aspirin versus placebo (OR 0.64, CI 0.16 to 2.56; 1 study, 41 participants; moderate-certainty evidence); comparing low-intensity warfarin with placebo (OR 1.76, 95% CI 0.78 to 3.99; 1 study, 107 participants; low-certainty evidence); comparing sulphinpyrazone versus placebo (OR 0.43, 95% CI 0.03 to 5.98; 1 study, 16 participants; low-certainty evidence) and comparing GTN patch and placebo (OR 1.26, 95% CI 0.63 to 2.54; 1 study, 167 participants; moderate-certainty evidence). The single trial evaluating warfarin was terminated early because of major bleeding events in the warfarin group. Only two studies published data on the secondary outcome of related interventions (surgical or radiological); there was insufficient evidence to determine if there was a difference in related interventions between placebo and treatment groups. None of the included studies reported on the duration of hospital stay.  Most studies reported complications ranging from mortality to nausea. However, data on complications were limited and reporting varied between studies.

AUTHORS' CONCLUSIONS

The meta-analyses of three studies for ticlopidine (an antiplatelet treatment), which all used the same dose of treatment but with a short follow-up of only one month, suggest ticlopidine may have a beneficial effect as an adjuvant treatment to increase the patency of AVFs and AVGs in the short term. There was insufficient evidence to determine if there was a difference in graft patency between placebo and other treatments such as aspirin, fish oil, clopidogrel, dipyridamole, dipyridamole plus aspirin, warfarin, sulphinpyrazone and GTN patch. The certainty of the evidence was low to moderate due to short follow-up periods, the small number of studies for each comparison, small sample sizes, heterogeneity between trials and risk of bias due to incomplete reporting. Therefore, it appears reasonable to suggest further prospective studies be undertaken to assess the use of these antiplatelet drugs in renal patients with an AVF or AVG.

Hydroxysafflor Yellow A inhibits the viability and migration of vascular smooth muscle cells induced by serum from rats with chronic renal failure via inactivation of the PI3K/Akt signaling pathway

It has been reported that the viability and migration of vascular smooth muscle cells contributes to arteriovenous fistula stenosis. Hydroxysafflor Yellow A (HSYA) has been demonstrated to inhibit the viability and migration of VSMCs by regulating Akt signaling. The present study aimed to investigate the role of HSYA on the viability and migration of human umbilical vein smooth muscle cells (HUVSMCs) following stimulation using serum from rats with chronic renal failure (CRF), and to determine the effects of HSYA on PI3K/Akt signaling. Wistar rats were randomly divided into two groups, control and CRF groups. Serum from each group was collected to stimulate the HUVSMCs. Cell Counting Kit-8 and wound healing assays were performed to assess cell viability and migration, respectively. Flow cytometry analysis was performed to assess apoptosis, and western blot analysis was performed to detect protein expression levels of PI3K and Akt. Nitric oxide (NO) production was measured using the Nitrate/Nitrite assay kit. The results demonstrated that serum from CRF rats significantly enhanced cell viability, migration and apoptosis, the effects of which were reversed following treatment with HSYA. In addition, CRF serum decreased NO and endothelial NO synthase expression, whilst increasing the protein expression levels of PI3K and phosphorylated-Akt in HUVSMCs. Notably, treatment with HSYA markedly restored NO production and inactivated the PI3K/Akt signaling pathway. Furthermore, the PI3K/Akt inhibitor, AMG511, exerted similar effects to HSYA. Taken together, the results of the present study suggest that HSYA suppresses cell viability and migration in the presence of CRF serum by inactivating the PI3K/Akt signaling pathway.

A novel technique using long segment patch angioplasty maturation to increase the maturation rate of arteriovenous fistulas

OBJECTIVE

Given the superior patency of arteriovenous fistulas (AVFs) and the decreased risk of infection compared with arteriovenous grafts, the Kidney Disease Outcomes Quality Initiative guidelines have recommended the fistula-first approach. However, ∼20% to 60% of all fistulas will fail to mature. We have described our experience with a novel technique using bovine pericardial patch angioplasty to increase the rate of AVF maturation.

METHODS

We used 2-cm × 9-cm-long or 2.5-cm × 15-cm-long segment pericardial patch angioplasty to assist in the maturation of AVFs. A single-center, retrospective cohort study was conducted of all patients who had undergone patch angioplasty maturation (PAM) for AVFs that had failed to mature. The outcomes of interest were maturation status and patency, censored by the death and last known follow-up dates.

RESULTS

From March 2007 to October 2019, 139 patients had undergone PAM. Follow-up data were available for 137 of the 139 patients (98.6%), with 126 AVFs (92.0%) progressing to maturation. Of the 126 patients with AVFs that had progressed to maturity, the previous hemodialysis (HD) method was known for 88 patients (69.8%). Of these 88 patients, 70 (79.5%) had previously been receiving HD via an HD catheter. Using a Kaplan-Meier estimator censored for death and loss to follow-up, the assisted primary patency rates at 1, 2, and 3 years were 87.3%, 78.1%, and 68.0%, respectively. Of the 137 patients, 69 (54.8%) had required no additional interventions after patch angioplasty. The complications requiring intervention were stenosis (n = 45; 32.8%), thrombosis (n = 10; 7.3%), infection (n = 3; 2.2%), steal syndrome (n = 3; 2.2%), noninfected wound complications (n = 1; 0.8%), and pseudoaneurysm (n = 1; 0.8%). The average interval to intervention after patch angioplasty was 4.56 months.

CONCLUSIONS

Long-segment bovine pericardial PAM can be performed safely to treat nonmaturing AVFs, with a 92.0% successful maturation rate and patency rates comparable to those for AVFs. PAM should be a consideration for patients with nonmaturing AVFs.

Initial single-center experience with a new external support device for the creation of the forearm native arteriovenous fistula for hemodialysis

OBJECTIVE

To assess and compare the maturation rate of the native radiocephalic arteriovenous fistula (RC-AVF) created with and without a nitinol external support (VasQ™ Laminate Medical Technologies Ltd, Tel Aviv, Israel).

METHODS

Data of all consecutive patients who underwent the creation of native RC-AVFs at our center between October 2018 and January 2020 was prospectively collected and retrospectively analyzed.Selected patients who had a suitable vein and a radial artery with triphasic flow at preoperative duplex ultrasound exam and were selected for the creation of a radiocephalic fistula were included. Exclusion criteria were: malignant tumors, acute renal failure, previous upper limb revascularization, and septic status. Patency and maturation, vein, and artery diameter and blood flow rate were assessed at the following intervals: post-operatively, 24 h post-operatively, 1 month, 3 months, and 6 months post-operatively.

RESULTS

Forty-nine patients (31 males, mean age 65.7 years old) were included. Patients who received VasQ™ devices were 25 (VasQ group), the other 24 formed the control group. All patients underwent radio-cephalic AVF placement (21 on the wrist, 20 on the forearm, 8 on the proximal forearm). There were no perioperative complications and fatalities. At 1, 3, and 6 months, primary patency rates were 96 ± 4%, 96 ± 4%, 91 ± 6% (VasQ group) versus 87 ± 7%, 87 ± 7%, 80 ± 9% (control group, P 0.17), secondary patency rates were 96 ± 4%, 96 ± 4%, 91 ± 6% (VasQ group) versus 95 ± 4%, 90 ± 7%, 90 ± 7% (control group, P 0.79). A significantly larger vein diameter increase postoperatively (P 0.009) and a greater maturation rate (96% vs 74%, p 0.044) were found in the VasQ group compared to the control group.

CONCLUSIONS

The use of the VasQ™ device was associated with higher maturation rates and larger vein diameters postoperatively. The patency rates were slightly higher but not significantly. Further studies are needed to confirm these findings.

Outcome of Permanent Vascular Access with Vein ≤ 2.2 mm in Diameter

OBJECTIVE

End-stage renal disease patients with vein diameter of ≤2.2 mm can undergo autogenous arteriovenous fistula (AVF) formation with the acceptable results.

METHODS

This observational retrospective study of prospectively collected data analyzed end-stage renal disease patients with a vein diameter of ≤ 2.2 mm, who underwent AVF formation at Shifa International Hospital Islamabad from January 2009 to December 2017. The fistulae were observed for immediate success and maturity at 3 months. The chi-square test was used to determine the effect of vein diameter on final maturity. All data were analyzed using SPSS.

RESULTS

The total number of patients with vein diameter of ≤2.2 mm was 38, with a mean age of 46.76 ± 12.790 years. Vein diameters ranged from 1.6 to 2.2 mm. Immediate success was observed in 35 (92.1%) cases. Veins of 31 (81.6%) patients showing maturity at 3 months and were used for hemodialysis. The overall success rate for the small caliber veins was 82%.

CONCLUSION

Although end-stage renal disease patients present late with very small diameter veins, these veins should still be accommodated for permanent vascular access, because their maturity rates are still acceptable, even though these are lower than those of patients with adequate sized veins.

Mid-term results of tunneled brachial venous hemodialysis catheter placement: Our single-center experience with 21 patients

Background

This study aims to analyze the safety and efficacy of permanent hemodialysis catheter insertion via the brachial vein in unsuitable patients for catheter insertion from other vascular access sites.

Methods

A total of 21 patients (6 males, 18 females; mean age: 54.4±11.3 years; range, 48 to 77 years) who underwent permanent hemodialysis catheter insertion via the brachial vein between February 2019 and February 2020 were retrospectively analyzed. All patients underwent brachial venous tunneled catheter insertion under the ultrasound guidance and under local anesthesia. Transthoracic echocardiography was performed before and six months after catheter insertion. The primary patency rate of the catheter at six months of follow-up, potential associated complications of a permanent hemodialysis catheter including catheter thrombosis and catheter infections, and all-cause mortality rates were recorded.

Results

Catheter removal was required in eight patients (catheter thrombosis, n=5; catheter infection, n=2; and extensive hematoma, n=1). The catheters were patent in the remaining 13 (62%) patients at six months. Mortality occurred in one patient due to bacterial pneumonia. No life-threatening complications including hemothorax or pneumothorax and neurological injury was observed in any of the patients.

Conclusion

Our study results show that brachial venous tunneled catheter placement for hemodialysis can be a safe and valid alternative to catheter insertion from the jugular or subclavian veins for vascular access in patients with end-stage renal disease.

Preoperative color Doppler ultrasound parameters for surgical decision-making in upper arm arteriovenous fistula maturation

OBJECTIVE

Current scientific evidence is insufficient to determine the best vascular access for each patient. It is an unmet clinical need because vascular access dysfunction accounts for 20% to 30% of hospital admissions. Our aim was to evaluate preoperative color flow Doppler ultrasound (CDUS)-derived parameters (vein diameter and brachial artery flow and diameter) and their effect interaction with comorbidities as predictors of brachiocephalic (BC) and brachiobasilic (BB) arteriovenous fistula (AVF) maturation.

METHODS

A prospective analysis was performed of patients who underwent BC and BB AVF as primary definitive vascular access between January 2016 and May 2017. Variables included patients' demographics, comorbidities, medication, preoperative blood pressure, and CDUS-derived parameters. Outcomes were patency 48 hours after surgery and fistula maturation at 6 and 12 weeks. Nonparametric descriptive and univariate statistics were used. Logistic regression models and receiver operating characteristic curve analyses were performed.

RESULTS

There were 132 patients (91 with BC AVF and 41 with BB AVF) included. The 48-hour patency was 91.7%. AVF maturation at 6 weeks was observed in 71.3%, and AVF maturation at 12 weeks was observed in 66.3%. There were no associations in univariate and multivariate logistic regression analysis between AVF maturation and comorbidities. Systolic blood pressure was an independent predictor of 48-hour patency with an optimized cutoff of 154 mm Hg (area under the curve, 0.73; P = .013; Youden index, 0.40). Vein diameter with tourniquet was an independent predictor of AVF maturation at 6 and 12 weeks with an optimized cutoff of 3.9 mm (area under the curve, 0.74; P < .001; Youden index, 0.38).

CONCLUSIONS

AVF maturation was independent of comorbidities. Systolic blood pressure ≥154 mm Hg and vein diameter with tourniquet ≥3.9 mm were the associated conditions that better predicted BC and BB AVF maturation. There were no effect interactions between CDUS-derived parameters and associated comorbidities.

Real-World Usage of the WavelinQ EndoAVF System

BACKGROUND

Dependent on existing deep to superficial perforating venous branches, the WavelinQ EndoAVF System is a novel technique used to create an arteriovenous fistula (AVF) between ulnar or radial veins and concomitant arteries for dialysis access. We sought to examine a single center's success rates and short-term follow-up using this device.

METHODS

All consecutive patients undergoing placement of a WavelinQ AVF from October 2018 to July 2019 were included. Preoperative/intraoperative variables including demographics, preoperative/postoperative duplex ultrasonography, success rate of procedure, and subsequent endovascular/surgical procedures were obtained. Descriptive statistics and comparison of groups requiring subsequent intervention were performed.

RESULTS

Thirty-five patients underwent placement of the WavelinQ AVF, with 32 (91%) patients having at least one documented follow-up. These patients were predominantly male (23/32, 72%) with an average age of 60.2 and 23 of 32 (72%) patients were on dialysis. Initial fistula creation success rate was 100%. Average procedural length was 120 min, fluoroscopy time 9.6 min, and contrast usage 52.2 mL. Eight of 32 (25%) patients had perioperative complications (3 hematomas, 3 contrast extravasations, 1 resolved vessel spasm all resolving spontaneously, and 1 pseudoaneurysm requiring surgical repair). Thirteen of 32 (41%) patients underwent subsequent endovascular interventions to assist with maturation [9/32 (28%) branch coiling, 5/32 (16%) angioplasty/stenting, and 3/32 (9%) access thrombectomy] and 4 of 32 (13%) patients required subsequent surgical interventions (1 pseudoaneurysm repair, 1 revision of fistula, and 2 definitive AVF creation in thrombosed grafts). The majority of accesses (30/32, 94%) were ulnar-ulnar fistulas and overall patency at average follow-up of 73 days was 88% (28/32) with average brachial artery inflow volume of 1,078 cc/min and average cephalic vein (18/32) outflow volume of 447 cc/min. Eleven of 23 (48%) patients on dialysis were successfully using the EndoAVF at follow-up.

CONCLUSIONS

The WavelinQ AVF system has a high initial procedural success rate, although a significant portion of patients require subsequent endovascular procedures to aid in maturation. Further work on determining factors predictive of need for reintervention is necessary.

Diagnosis and Treatment of Nonmaturing Fistulae for Hemodialysis Access via Transradial Approach: A Case-Control Study

PURPOSE

To compare outcomes of transradial access for endovascular treatment of nonmaturing hemodialysis fistulae compared to brachial arteriography followed by unidirectional or bidirectional fistula access for intervention.

MATERIALS AND METHODS

In this institutional review board-approved, retrospective, case-control study, 56 consecutive patients with nonmaturing arteriovenous fistulae underwent percutaneous intervention between 2015 and 2018. The transradial group (n = 28) underwent radial artery access for diagnostic fistulography and intervention. The control group (n = 28) underwent retrograde brachial artery access for fistulography followed by unidirectional/bidirectional fistula access for intervention. Both groups had similar demographics, fistula characteristics, and stenosis locations.

RESULTS

Fewer punctures were required in the transradial group compared to controls (1.2 vs 2.4, P < .0001), and procedure time was shorter (64.9 vs 91.3 minutes, P = .0016). Anatomic, technical, and clinical success rates trended higher in the transradial group compared to controls (93% vs 86%, 96% vs 89%, and 82% vs 64%, respectively). Nonmaturation resulting in fistula abandonment was lower in the transradial group (3.7% vs 25%, P = .025). Primary unassisted patency at 3, 6, and 12 months was 77.1% ± 8.2%, 73.1% ± 8.7%, and 53.3% ± 10.6% in the transradial group, respectively, and 63.0% ± 9.3%, 55.6% ± 9.6%, and 48.1% ± 9.6% in the control group, respectively (P = .76). Primary assisted patency at 12 months was 92.3% ± 5.3% in the transradial group compared to 61.8% ± 9.6% at 12 months in the control group (P = .021). No major complications occurred. Minor complications were lower in the transradial group than in the control group (14% vs 39%, P = .068).

CONCLUSIONS

Treatment of nonmaturing fistulae via a transradial approach was safe, improved midterm patency, and was associated with lower rates of fistula abandonment.

Development and validation of a clinical score to predict 1-year survival of arteriovenous fistula access: a diagnostic study

Purpose

To develop and validate a clinical scoring model to predict 1-year access survival among end-stage renal disease (ESRD) patients who received a new arteriovenous fistula (AVF).

Methods

The data of 195 ESRD patients in the development cohort who underwent first-time AVF creation between January 2009 and June 2013 and who had successful cannulation for dialysis use were reviewed. The clinical features that were significantly associated with 1-year AVF survival were incorporated into a clinical scoring model. The validity of this clinical score was then tested in a validation cohort of 204 ESRD patients who received a new AVF between July 2013 and December 2017.

Results

Of the 195 patients in the development cohort, 168 patients (86.2%) had a well-functioning AVF at 1 year. Absence of diabetes mellitus, no previous history of central venous catheter insertion, and absence of intervention performed to achieve access maturation were positively associated with 1-year AVF survival. These 3 factors were incorporated into a clinical scoring model, which ranged from 0 to 4 points. For a cutoff score of ≥3, the sensitivity, specificity and area under the receiver operating characteristic curve to predict 1-year AVF survival were 81.5%, 70.4%, and 0.760, respectively. The predictive performance of the clinical score was confirmed in the validation cohort, with a sensitivity of 76.1%, a specificity of 64.4% and an area under the curve of 0.703.

Conclusion

The scoring model using clinical data yielded acceptable performance in predicting 1-year access survival among patients receiving a new AVF.

Brachial vein transposition: an alternative to hemodialysis arteriovenous graft

Background

There is currently a worldwide effort to increase the options for autogenous hemodialysis access.

Objectives

To evaluate patency and complications of brachial vein transposition compared to other autogenous hemodialysis accesses.

Methods

A retrospective evaluation of 43 patients and 45 procedures. Patients who did not have adequate superficial veins according to duplex scanning were allocated to brachial vein transposition. The sample was thus divided in two groups, as follows: A: brachial vein transposition n=10 and B: other autogenous accesses n=35.

Results

There were no statistical differences between the two groups in terms of age diabetes, systemic arterial hypertension, dyslipidemias, arteriopathies, neoplasms, kidney disease stage, donor artery diameter, recipient vein diameter, systolic blood pressure in the operated limb, postoperative ischemia, hematoma, or infection. There were no statistical differences in terms of patency on day 7: A 80% vs. B 90% p=0.6, on day 30: A 80% vs. B 86% p=0.6, or on day 60: A 60% vs. B 80% p=0.22. There were statistical differences between the groups for number of previous fistulae A 1.0 ± 0.44 vs. B 0.6 ± 0.3 p = 0.04 and upper limb edema A: 20% x B 0% p = 0.04. A vein with diameter of less than 3 mm was associated with an increased risk of early occlusion (RR = 8 p = 0.0125). During the study period there were no procedures using grafts.

Conclusions

Transposition of brachial vein is an alternative to arteriovenous graft.

Comparison of outcomes between type 2 diabetic and non-diabetic incident hemodialysis patients with functioning arteriovenous fistulas

This study compared clinical outcomes of patient survival and arteriovenous fistula (AVF) patency between incident hemodialysis patients with and without type 2 diabetes mellitus (T2DM).Between January 2011 and December 2013, 384 consecutive incident hemodialysis patients with confirmed first upper-extremity AVF placement were divided into a T2DM group (n = 180, 46.9%) and a non-DM group (n = 204, 53.1%) and analyzed retrospectively. The primary outcome was all-cause mortality, and secondary outcome was AVF patency.Patients in the T2DM group had a higher prevalence of hypertension (P = .02), smoking (P < .01), cardiovascular disease (P < .01), history of cerebrovascular accident (CVA) (P < .01), and peripheral arterial occlusive disease (P < .01) than those in the non-DM group. On Kaplan-Meier survival analysis, the overall survival and AVF patency rates were significantly higher in the non-DM group relative to the T2DM group (both P < .01). In the adjusted model, older age (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.02-1.06; P < .01), T2DM (HR, 1.76; 95% CI, 1.12-2.77; P = .014), and history of CVA (HR, 1.76; 95% CI, 1.04-2.98; P = .04) were significantly associated with an increased risk of mortality. Older age and T2DM were independently associated with decreased primary (HR, 1.03; 95% CI, 1.02-1.04; P < .01, HR, 1.69; 95% CI, 1.22-2.33; P < .01, respectively) and secondary (HR, 1.03; 95% CI, 1.01-1.04; P < .01, HR, 2.07; 95% CI, 1.42-3.00; P < .01, respectively) AVF patency during follow-up.Compared with patients in the non-DM group, patients in the T2DM group had a higher mortality rate and worse AVF patency rates.

Patency rates of arteriovenous fistulas created before versus after hemodialysis initiation

In an incident hemodialysis (HD) population, we aimed to investigate whether arteriovenous fistula (AVF) creation before HD initiation was associated with improved AVF patency compared with AVF creation from a central venous catheter (CVC), and also to compare patient survival between these patients. Between January 2011 and December 2013, 524 incident HD patients with identified first predialysis vascular access with an AVF (pre-HD group, n = 191) or an AVF from a CVC (on-HD group, n = 333) were included and analyzed retrospectively. The study outcome was defined as AVF patency and all-cause mortality (time to death). On Kaplan-Meier survival analysis, primary and secondary AVF patency rates did not differ significantly between the two groups (P = 0.812 and P = 0.586, respectively), although the overall survival rate was significantly higher in the pre-HD group compared with the on-HD group (P = 0.013). On multivariate analysis, well-known patient factors were associated with decreased primary (older age and diabetes mellitus [DM]) and secondary (DM and peripheral arterial occlusive disease) AVF patency, whereas use of a CVC as the initial predialysis access (hazard ratios, 1.84; 95% confidence intervals, 1.20-2.75; P = 0.005) was significantly associated with worse survival in addition to well-known patient factors (older age, diabetes mellitus, and peripheral arterial occlusive disease). Worse survival in the on-HD group was likely confounded by selection bias because of the retrospective nature of our study. Therefore, the observed lower mortality associated with AVF creation before HD initiation is not fully attributable to CVC use, but rather, affected by other patient-level prognostic factors. There were no CVC-related complications in the pre-HD group, whereas 10.2% of CVC-related complications were noted in the on-HD group. In conclusion, among incident HD patients, compared with patients who underwent creation of an AVF from a CVC, initial AVF creation showed similar primary and secondary AVF patency rates, but lower mortality risk. We also observed that an initial CVC use was an independent risk factor associated with worse survival. A fistula-first strategy might be the best option for incident HD patients who are good candidates for AVF creation.

Arterial Aneurysmal Degeneration With Venous Varicosity Following Ligation of an Arteriovenous Fistula in a Kidney Transplant Recipient

Late occurrence of arterial aneurysms following ligation of a hemodialysis arteriovenous fistula (AVF) is rare. Here, we report the case of 51-year-old male patient with an AVF in which arterial aneurysms developed. The patient had undergone left arm radiocephalic (RC) AVF creation for hemodialysis in 2000. He had received a living related donor kidney transplantation from his father in the same year. His RC AVF was ligated in 2009. However, his arm continued to gradually grow in size even after ligation and he visited a hospital for acute pain and erythema around the left elbow in 2017. Since his renal allograft function had been deteriorating, duplex ultrasonography was performed. It revealed 2 giant aneurysms in the distal brachial artery and proximal radial artery with diameters of 3.0 and 2.8 cm, respectively. The superficial veins of the left upper arm showed varicosity and had multifocal thrombi. Microfistula between the artery and vein was revealed by contrast-enhanced ultrasonography and the contrast agent microbubbles flowed from the artery toward the superficial veins. The aneurysms were resected and the arteries were reconstructed with great saphenous vein. There were no perioperative complications and the patient was discharged on postoperative day 3. No complications in the arm or bypass conduit have occurred at 6 months after the surgery.

Subjective Global Assessment-Dialysis Malnutrition Score and arteriovenous fistula outcome: A comparison with Charlson Comorbidity Index

INTRODUCTION:

Malnutrition is a well-recognized risk factor for all-cause mortality in hemodialysis patients. However, its role for arteriovenous fistulas outcome has not been exhaustively investigated. Our aim was to point out the impact of Subjective Global Assessment-Dialysis Malnutrition Score as independent predictor of arteriovenous fistulas thrombosis (vascular access thrombosis) and/or significant stenosis (vascular access stenosis). In addition, we compared it with the widespread Charlson Comorbidity Index.

METHODS:

We assessed 57 hemodialysis patients for a 2-year interval and evaluated the incidence of vascular access thrombosis and/or stenosis. Linear regression analysis was used to test the relation of variables with Subjective Global Assessment-Dialysis Malnutrition Score at baseline. Logistic and Cox regression analysis evaluated markers as predictors of both vascular access thrombosis and stenosis. Receiver operating characteristic curve analysis was used to compare area under the curve values of Subjective Global Assessment-Dialysis Malnutrition Score, Charlson Comorbidity Index, and modified Charlson Comorbidity Index.

RESULTS:

Age and Charlson Comorbidity Index were positively related to Subjective Global Assessment-Dialysis Malnutrition Score: B = 0.06 (95% CI = 0.01; 0.11) and B = 0.31 (95% CI = 0.01; 0.63). Higher albumin and normalized protein catabolic rate levels had a protective role against vascular access failure: OR = 0.67 (95% CI = 0.56; 0.81) and OR = 0.46 (95% CI = 0.32; 0.67), respectively. Higher Subjective Global Assessment-Dialysis Malnutrition Score and Charlson Comorbidity Index values were significant risk factors: HR = 1.42 (95% CI = 1.04; 1.92) and HR = 1.48 (95% CI = 1.01; 2.17), respectively. Area under the curve of Subjective Global Assessment-Dialysis Malnutrition Score was significantly higher than those of both Charlson Comorbidity Index and modified Charlson Comorbidity Index: 0.70 (95% CI = 0.50; 0.88) versus 0.61 (95% CI = 0.41; 0.80) and 0.55 (95CI% = 0.41; 0.70).

CONCLUSION:

Subjective Global Assessment-Dialysis Malnutrition Score, as well as Charlson Comorbidity Index, are useful tools to predict vascular access failure and should be carefully and periodically evaluated in order to check significant variations that may compromise vascular access survival.

Dialysis Access, Infections, and Hospitalisations in Unplanned Dialysis Start Patients: Results from the Options Study

Introduction

Unplanned dialysis start (UPS) associates with worse clinical outcomes, higher utilisation of healthcare resources, lower chances to select dialysis modality and UPS patients typically commenced in-centre haemodialysis (HD) with central venous catheter (CVC). We evaluated patient outcomes and healthcare utilisation depending on initial dialysis access (CVC or PD catheter) and subsequent pathway of UPS patients.

Methods

In this study patient demographics, access procedures, hospitalisations, and major infectious complications were analysed over 12 months in 270 UPS patients. PD technique survival and impact of switching from HD to PD was examined along with logistic regression to investigate factors predicting AV fistula formation.

Results

72 UPS patients started with PD catheter and 198 with CVC. PD patients were older and more comorbid but had a significantly lower number of access procedures while there was no difference in hospitalisation or major infections. 13/72 initial PD patients switched to HD and 1-year technique survival was 79%. 158/198 patients remained on HD and 73/158 reported permanent access formation. Older age, OR = 0.34 (CI, 0.17-0.68) and cardiac failure, OR = 0.31(CI, 0.13–0.78), were significant negative predictors of receiving fistula. Younger patients, OR = 0.29 (CI, 0.11–0.79) and those who received AVF, OR = 0.11 (CI, 0.03–0.38), had significantly lower odds of death.

Discussion

UPS with initial PD was possible in many patients and was associated with lower requirement for access procedures. AVF formation in UPS patients starting on HD was associated with better 1-year survival. Modality switching in UPS patients requires careful clinical management, including clinical practice patterns promoting permanent HD access formation.

Arteriovenous Fistulae for Haemodialysis: A Systematic Review and Meta-analysis of Efficacy and Safety Outcomes

BACKGROUND

Arteriovenous fistulae are the currently recommended gold standard vascular access modality for haemodialysis because of their prolonged patency, improved durability, and low risk of infection for those that mature. However, notable disadvantages are observed in terms of protracted maturation time, associated high rates of catheter use, and substantial abandonment rates. The aim of this study was to quantitatively summarize the outcomes of fistula patency, infection, maturation, and abandonment published in the scientific literature.

METHODS

This was a systematic review and meta-analyses of studies evaluating fistula outcomes. Literature searches were conducted in multiple databases to identify observational and interventional studies of mean fistula patency rates at 1 year, infection risk, maturation time, and abandonment. Digitisation software was used to simulate individual patient level data from Kaplan-Meier survival plots.

RESULTS

Over 8000 studies were reviewed, and from these, 318 studies were included comprising 62,712 accesses. For fistulas the primary unassisted, primary assisted, and secondary patency rates at one year were 64%, 73% and 79% respectively, however not all fistulas reported as patent could be confirmed as being clinically useful for dialysis (i.e. functional patency). For fistulas that were reported as mature, mean time to maturation was 3.5 months, however only 26% of created fistulas were reported as mature at 6 months and 21% of fistulas were abandoned without use. Overall risk of infection in fistula patients was 4.1% and the overall rate per 100 access days was 0.018.

CONCLUSIONS

Reported fistula patency rates may overstate their potential clinical utility when time to maturation, maturation rate, abandonment and infection are considered. Protracted maturation times, abandonment and infection all have a significant impact on evaluating the clinical utility of fistula creation. A rigorous and consistent set of outcomes definitions for hemodialysis access are necessary to clarify factors contributing to fistula success and the clinical consequence of fistula failure.

Contribution of monoamine oxidases to vascular oxidative stress in patients with end-stage renal disease requiring hemodialysis

Arteriovenous fistula (AVF) is the "lifeline" for patients with end-stage renal disease (ESRD) undergoing hemodialysis. AVF maturation failure is a poorly understood process, one of the contributors being endothelial dysfunction due to oxidative stress. Monoamine oxidases (MAOs) A and B were recently identified as novel sources of vascular oxidative stress. The aim of the present study was to assess the contribution of MAOs to the endothelial dysfunction in patients with ESDR with indication of hemodialysis. Fragments of brachial artery collaterals were harvested from ESRD patients during the surgical procedure aimed at creating the vascular access in the cubital fossa. The effect of increasing concentrations (10, 30, 100 μmol/L) of the irreversible MAO-A inhibitor, clorgyline, and MAO-B inhibitor, selegiline, on endothelial-dependent relaxation (EDR) in response to cumulative doses of acetylcholine was studied in isolated phenylephrine-preconstricted vascular rings. Hydrogen peroxide (H₂O₂) production was assessed using ferrous oxidation xylenol orange assay. We showed that incubation of brachial rings with MAO inhibitors significantly improved EDR and attenuated H₂O₂ generation in patients with ESRD. MAO-related oxidative stress might contribute to the primary dysfunction/non-maturation of the AVF and MAO inhibitors could improve maturation and long-term patency of the vascular access in dialysis patients.

Administration of a High-Dose Erythropoietin-Stimulating Agent in Hemodialysis Patients is Associated with Late Arteriovenous Fistula Failure

PURPOSE

Investigating the risk of vascular access failure is critical for maintenance hemodialysis (MHD) patients. Erythropoietin stimulating agents (ESA) typically used for anemia of chronic kidney disease (CKD) may also stimulate neointimal hyperplasia, which is the most important factor in late arteriovenous fistula (AVF) failure. The aim of this study was to investigate whether ESA treatment is associated with late AVF failure.

MATERIALS AND METHODS

The late AVF failure group comprised 51 patients who underwent percutaneous intervention or surgery for fistula revision after successful use for at least three months. There were 51 controls whose AVF had been patent for at least 24 months.

RESULTS

The mean time from the first cannulation to late loss of AVF patency was 8.4±4.2 months. The average weekly dose of ESA was significantly higher in patients with AVF failure (4782.2±2360.5 IU/mL/wk vs. 7161.8±2775.2 IU/mL/wk, p<0.001). The only independent predictor of late AVF failure in multivariate analysis was high average ESA dose (odds ratio=1.015, 95% confidence interval=1.002-1.028, p=0.022).

CONCLUSION

Patients with late AVF patency loss exhibit an association with a higher dose of ESA, although causality is unproven. Further study to elucidate potential mechanisms is warranted.