True aneurysm in autologous hemodialysis fistulae: definitions, classification and indications for treatment

Skin pigmentation as landmark for arteriovenous fistula cannulation in hemodialysis

BACKGROUND

The cannulation of the arteriovenous fistula (AVF) for hemodialysis (HD) has traditionally depended on the nurse's tactile sensation, which has been associated with suboptimal needle placement and detrimental effects on vascular access (VA) longevity. While the introduction of ultrasound (US) has proven beneficial in mapping the AVF outflow vein and assisting in cannulation planning, aneurysmal deformations remain a common occurrence resulting from various factors, including inadequate cannulation techniques. Within this context, the utilization of skin pigmentation as a clinical landmark has emerged as a potential approach to enhance cannulation planning in HD.

METHODS

A prospective longitudinal study was undertaken to investigate the correlation between the occurrence of venous morphological deformations and the cannulation technique guided by skin pigmentation after a 2-month period of implementation.

RESULTS

Thirty patients were enrolled in the study with 433 cannulations being described within the first 2 months of AVF use. The overall rate of cannulation-related adverse events was 21.9%. Comparative analysis demonstrated a statistically significant relationship (p < 0.001) between aneurysmal deformation and non-compliance with the proposed cannulation technique, resulting in cannulation outside the designated points. Non-compliance was primarily attributed to nurse's decision (57.1%).

CONCLUSION

The integration of US mapping of the AVF outflow vein and the utilization of skin pigmentation as a guiding tool have shown promising results in enhancing cannulation planning over time. Consistent adherence to a cannulation technique other than the area technique has been found to reduce the risk of AVF morphological deformation. These findings underscore the potential benefits of incorporating skin pigmentation as a clinical landmark in cannulation practices, highlighting its ability to impact positively cannulation outcomes.

Impact of arteriovenous fistula aneurysms on a UK dialysis populations' perception of vascular access

BACKGROUND

Clinically-oriented outcome measures are increasingly being recognized as lacking in consideration of factors important to patients. There is an emerging move of guideline bodies advocating a more patient-centred approach. Aneurysms in autogenous arteriovenous fistula (AVF) can be considered unsightly and a constant reminder for patients of their dependence on dialysis. However, their impact on patient's perception has not previously been reported.

METHODS

Between April 2017-18, the Vascular Access Questionnaire (VAQ) was administered to prevalent haemodialysis patients across ten dialysis units via structured interviews, as part of a quality improvement project. Data for the subgroup of patients with aneurysmal AVF (categorised as per classification by Valenti et al.), were retrospectively evaluated and compared to the wider cohort.

RESULTS

Data were collected for 539 patients (median age: 66 years; 59% male), of whom 195 (36%) had aneurysmal AVF, with Type 2 morphology (cannulation site) being the most common (75%). Duration of AVF was found to be significantly associated with aneurysmal development, with estimated likelihoods of 11%, 43% and 61% after one, five and ten years, respectively. Interestingly, patients with diabetes had a significantly lower prevalence of aneurysmal development than those that were non-diabetic (25% vs. 43%, p < 0.001). Overall VAQ scores were not found to differ significantly by aneurysm status (p = 0.816) or across morphology types (p = 0.277). However, patients with aneurysmal AVF were significantly more concerned with the appearance of their AVF (p < 0.001) than the wider cohort. Despite this, patients with aneurysmal AVF gave significantly higher scores for satisfaction and ease of use and lower scores for bruising and clotting (p < 0.05).

CONCLUSIONS

Aneurysmal AVF are often cited as an important factor by patients for not proceeding with fistula formation. In this evaluation of patient reported experiences, those with aneurysmal AVF reported high satisfaction levels. This may help clinicians highlight positive patient reported outcomes of aneurysmal AVF during preprocedural consent processes.

Salvage Aneurysmorrhaphy as an Adaptable and Still Pertinent Technique in the Management of Challenging True Aneurysms of Arteriovenous Fistulas: A Case Series of Different Variations, With Illustrative Surgical Pictures

Introduction

Aneurysmorrhaphy, described as reduction aneurysmoplasty, partial aneurysmectomy, or vessel wall recalibration, can be considered a suitable surgical plan for true aneurysms of arteriovenous fistulas (AVFs), allowing for a dynamic approach to reconstruction of aneurysmal AVFs of different severities, ensuring salvage of the native access.

Report

Six challenging cases of AVF aneurysms are presented, some with extremely dilated and tortuous megafistulas, for which three surgical technique variations were performed. The patients had a mean age of 59.2 years, 50% were female, with brachiocephalic (n = 5, 83.3%) or brachiobasilic (n = 1, 16.7%) AVFs. The fistulas were created an average of 4.67 years previously, and the aneurysms had an average maximum diameter of 37.5 mm (range 25-60 mm). Surgical indications were rupture risk, thrombosis, or outflow stenosis compromising haemodialysis, infections, and concerns for quality of life (affected by post-puncture bleedings, disfiguring aesthetics, pain, and discomfort). The surgical techniques were simple aneurysmorrhaphy (n = 3, 50%), aneurysmorrhaphy with partial excision of aneurysmal segment with end to end anastomosis of venous ends (n = 2, 33.3%), and aneurysmorrhaphy with establishment of new venous outflow (n = 1, 16.7%). All AVFs were patent post-operatively and at follow up (mean 5.6 months, median one month). Haemodialysis was resumed through the AVFs at a mean of 2.17 weeks post-operatively, with placement of an alternative route for haemodialysis in the meantime. No patients experienced post-operative complications.

Discussion

Experience with the more challenging cases shows that aneurysmorrhaphy can still be considered an acceptable, flexible, and pertinent method for salvage of megafistulas, giving the surgeon the much needed versatility to adapt to anatomical and pathological variations, with high patency rates and minimal complications, especially when other treatment options are not possible in complicated cases. AVF salvage through aneurysmorrhaphy allows for a dynamic approach to the reconstruction of severely tortuous, dilated veins, ensuring patency of the native AVF.

Internal fistula stenosis with true pseudoaneurysm formation in a patient on maintenance hemodialysis: A case report

BACKGROUND

Arteriovenous fistula stenosis can directly lead to the formation of autologous arteriovenous fistula aneurysms (AVFAs), but the coexistence of true and pseudoaneurysms is relatively rare. The coexistence of true and pseudoaneurysms increases the risk of rupture of the arteriovenous fistula and complicates subsequent surgical intervention, potentially posing a threat to the patient's life, and thus requires significant attention.

CASE PRESENTATION

The patient presented with arteriovenous fistula (AVF) after hemodialysis 6 years ago. 2 years ago, the patient presented with a mass that had formed near the left forearm arteriovenous fistula and gradually increased in size. Preoperatively, the AVF stenosis was identified as the cause of the mass formation, and the patient was operated on. First, the blood flow was controlled to reduce the pressure at the aneurysm, and then the incision was enlarged to separate the AVF anastomosis from the mass area. The stenotic segment of the true and pseudo aneurysms and cephalic vein was removed and the over-dilated proximal cephalic vein was locally narrowed and subsequently anastomosed with the proximal radial artery to create AVF. The patient was dialyzed with an internal fistula the next day and showed no clinical manifestations related to end-limb ischemia.

CONCLUSION

We removed a true pseudoaneurysm in AVF and secured the patient's vascular access. This report provides an effective strategy to manage this condition.

Evaluation of Central Venous Catheter for Dialysis Associated with Bloodstream Infections

Objective: Hemodialysis (HD) catheter-related bloodstream infections (CRBSIs) are a major complication of long-/short-term catheter. Material and Methods: Patients with HD CRBSIs were identified, and their blood was taken and sent to clinical pathology for culture and sensitivity testing. The inclusion criteria were adults with end-stage renal disease who required urgent HD access in the presence of a central venous catheter (CVC) infection. Results: The most common isolates among the patients with CRBSIs were gram-positive microorganisms (57.5%) and gram-negative organisms (42.5%). Overall, in our entire study, Staphylococcus aureus was the most common pathogen isolated, accounting for 30%, followed by Pseudomonas aeruginosa (20%), coagulase-negative staphylococci (CoNS) (12.5%), Klebsiella spp. and Acinetobacter (10%), Staphylococcus epidermidis (7.5%), and methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Staphylococcus hominis, and Enterococcus faecalis (2.5%). The commonest bacterial in femoral was S. aureus, and for subclavian was Pseudomonas aeruginosa. All S. aureus were sensitive to aminoglycosides and quinolones. P. aeruginosa was sensitive to the third generation of cephalosporins, especially cefoperazone and carbapenem. Conclusion: Nontunneled CVCs used for more than 2 weeks could increase the risk of CRBSIs. Procalcitonin and erythrocyte sedimentation rate could predict the CRBSIs in this study. This study also revealed that the gram-positive bacteria were primadonna in dialysis of CRBSIs, and most of them were sensitive to aminoglycosides.

Comparison between transposed arteriovenous fistulas and arteriovenous graft for the hemodialysis patients: A meta-analysis and systematic review

It is challenging for a surgeon to determine the appropriate vascular access for hemodialysis patients whose cephalic vein is usually inaccessible. The purpose of the study is to compare the complications and patency rates between transposed arteriovenous fistulas (tAVF) and arteriovenous graft (AVG) for the hemodialysis patients. Studies were recruited from PubMed, Cochrane library, EMBASE, the web of science databases, and reviewing reference lists of related studies from the inception dates to September 2, 2021. Statistical analyses were conducted using the statistical tool Review Manager version5.3 (Cochrane Collaboration, London, UK). I2 > 50% was defined as a high degree of heterogeneity, and then a random-effects model was used. Otherwise, the fixed-effects model was used. Odds ratio with its 95% confidence interval (95% CI) was used. Thirty-three trials (26 retrospective studies, four randomized controlled trials, two prospective trials, and one controlled-comparative study) with 6430 enrolled participants were identified in our analysis. The results showed that tAVF was accompanied with lower thrombosis rate (103/1184 (8.69%) vs 257/1367 (18.80%); I2 = 45%; 95% CI, 0.34 (0.26, 0.45)) and infection rate (43/2031 (2.12%) vs 180/2147 (8.38%); I2 = 0%; 95% CI, 0.20 (0.14, 0.30)) than arteriovenous graft. The significantly better primary patency rates, secondary patency rates, and primary assisted patency rates during follow-up were found in tAVF. However, the failure rate and the prevalence of hematoma were significantly lower in AVG group. No evidence showed the rate of overall mortality, steal syndrome, and aneurysm reduced in tAVF. Our results showed that tAVF is a promising vascular access technique for hemodialysis patients whose cephalic vein is inaccessible. Our data showed that tAVF has less thrombosis, infection risk, and better patency rates when compared with AVG. However, more attentions need to be paid to transposed arteriovenous fistulas maturation and hematoma.

Comparison of Open and Endovascular Aneurysm Repair in Native Arteriovenous Fistulas

BACKGROUND

Arteriovenous accesses develop aneurysms (FA) during their active use, resulting in pain, erosion, bleeding, and difficulty in cannulation. This study aims to evaluate the outcomes of open and endovascular management of single FA in arteriovenous fistulas (AVF).

METHODS

A retrospective review of all upper extremity primary AVFs over 12 years was undertaken at a single center. Patients undergoing elective open and endovascular repair of a single FA were identified. Thirty-day outcomes, cannulation failure, line placement, re-intervention, and functional dialysis (continuous hemodialysis) for 3 consecutive months were examined.

RESULTS

Three hundred and seventy nine patients presented with a single FA that met the requirements for intervention: 126 (33%) underwent endovascular repair, and the remainder 253 (67%) underwent open repair. Preoperative fistulogram identified anatomically significant issues in 91% of the cases, and these were treated by balloon angioplasty: 10% within the fistula tract, 44% within the outflow tract, and 47% in the central veins. In open repair, 57% underwent plication, 35% underwent resection and re-anastomosis, and the remainder (8%) underwent interposition grafting. In endovascular repair, successful placement of a stent was achieved in all cases with 1 ± 2 (mean ± standard deviation [SD]) covered stents (diameter: 6 -8 mm) placed, achieving successful exclusion of the FA. The combination of early thrombosis and cannulation failures led to the greater need for a tunneled central line in endovascular repair (6.5% vs. 2.4%; endovascular versus open repair; P = 0.04). As a result, the mean time for establishing renewed access in the index AVF was significantly higher in endovascular repair (2 ± 3 vs. 2 ± 2 weeks, mean ± SD; endovascular open repair versus open repair; P = 0.001). In follow-up, there were more secondary interventions per year in the endovascular compared to open repair groups (3.1 vs. 1.4 secondary interventions per year; endovascular versus open repair; P = 0.04). Median functional dialysis durations were superior in the open repair (48 ± 6%, mean + standard error) compared to the endovascular repair at 5 years. (26 ± 7%; P = 0.03).

CONCLUSIONS

Open repair results in a more rapid return to access use, lower need for a tunneled central line, lower secondary re-intervention rates, and superior functional dialysis durations compared to endovascular repair. Open FA repair should be considered for symptomatic single FA repairs before endovascular FA repair.

Outcomes of one-stage and two-stage aneurysm repair in arteriovenous fistulae

OBJECTIVE

Maintenance of long-term arteriovenous access is important in long-term care for patients with end-stage renal disease. Arteriovenous access is associated in the long term with the development of fistula aneurysms (FAs). This study aims to evaluate the outcomes of staged FA treatment in dialysis access arteriovenous fistulae (AVF).

METHODS

A retrospective review of all patients over a 12-year period with primary autogenous AVF was undertaken at a single center. Patients undergoing elective open aneurysm repair were identified and were categorized into three groups: single FA repair (single, control group) and staged and unstaged repair of two FAs (staged and unstaged). A staged repair was a procedure in which the initial intent was to treat both aneurysms in the AVF and in which the most symptomatic aneurysm was treated first. When the incision from the first surgery had healed, the second symptomatic aneurysm in the AVF was treated. An unstaged repair was a procedure in which the initial intent was to repair both symptomatic aneurysms simultaneously. All patients had a fistulogram before the FA repair. Thirty-day outcomes, cannulation failure, line placement, reintervention, and functional dialysis (continuous hemodialysis for 3 consecutive months) were examined.

RESULTS

Five hundred twenty-seven patients presented with FA that met requirements for open intervention; 44% underwent single FA repair, whereas the remaining 34% and 22% underwent staged and unstaged repair of two FAs, respectively. The majority of patients were diabetic and Hispanic. Ninety-one percent of the patients required percutaneous interventions of the outflow tract (37%) and the central veins (54%). Thirty-day major adverse cardiovascular events were equivalent across all modalities. Thirty-day morbidity and early thrombosis (<18 days) were significantly higher in the unstaged group (4.3%) compared with the two other groups (1.3% and 2.1%, single and staged, respectively), which led to an increased need for a short-term tunneled catheter (8.9%) compared with the two other groups (3.4% and 4.4%, single and staged, respectively), Unstaged repair resulted in an increased incidence of secondary procedures (5.0%) compared with the two other groups (2.6% and 3.1%, single and staged, respectively). Functional dialysis at 5 years was equivalent in the single and staged groups but was significantly decreased in the unstaged group.

CONCLUSIONS

Open interventions are successful therapeutic modalities for FAs, but unstaged rather than staged repair of two concurrent FAs results in a higher early thrombosis, an increased secondary intervention rate, and a need for a short-term tunneled central line. Staged and single FA repairs have equivalent results. In the setting of two symptomatic FAs, staged repair is recommended.

Long-term results of autologous scaffold-free tissue-engineered vascular graft for hemodialysis access

BACKGROUND

The growing size of the end stage renal disease (ESRD) population highlights the need for effective dialysis access. Exhausted native vascular access options have led to increased use of catheters and prosthetic shunts, which are both associated with high risks of access failure and infection. Emerging alternatives include tissue-engineered vascular grafts (TEVG). Here we present the endpoint results for 10 ESRD patients with the scaffold-free tissue-engineered vascular access produced from sheets of extracellular matrix produced in vitro by human cells in culture.

METHODS

Grafts were implanted as arteriovenous shunts in 10 ESRD patients with a complex history of access failure. Follow-up included ultrasound control of graft morphology and function, dialysis efficiency, access failure, intervention rate, as well as immunohistochemical analysis of graft structure.

RESULTS

One patient died of unrelated causes and three shunts failed to become useable access grafts during the 3-month maturation phase. The 12-month primary and secondary patency for the other six shunts was 86%. Survival of six shunts functioning as the vascular access was 22 ± 12 months with longest primary patency of 38.6 months. The dialysis event rate of 3.34 per patient-year decreased significantly with the use of this TEVG to 0.67.

CONCLUSIONS

This living autologous tissue-engineered vascular graft seems to be an alternative to synthetic vascular access options, exhibiting advantages of native arteriovenous fistula.

Hemodialysis Access: US for Preprocedural Mapping and Evaluation of Maturity and Access Dysfunction

Patients with kidney failure require kidney replacement therapy. While renal transplantation remains the treatment of choice for kidney failure, renal replacement therapy with hemodialysis may be required owing to the limited availability and length of time patients may wait for allografts or for patients ineligible for transplant owing to advanced age or comorbidities. The ideal hemodialysis access should provide complication-free dialysis by creating a direct connection between an artery and vein with adequate blood flow that can be reliably and easily accessed percutaneously several times a week. Surgical arteriovenous fistulas and grafts are commonly created for hemodialysis access, with newer techniques that involve the use of minimally invasive endovascular approaches. The emphasis on proactive planning for the placement, protection, and preservation of the next vascular access before the current one fails has increased the use of US for preoperative mapping and monitoring of complications for potential interventions. Preoperative US of the extremity vasculature helps assess anatomic suitability before vascular access creation, increasing the rates of successful maturation. A US mapping protocol ensures reliable measurements and clear communication of anatomic variants that may alter surgical planning. Postoperative imaging helps assess fistula maturation before cannulation for dialysis and evaluates for early and late complications associated with arteriovenous access. Clinical and US findings can suggest developing stenosis that may progress to thrombosis and loss of access function, which can be treated with percutaneous vascular interventions to preserve access patency. Vascular access steal, aneurysms and pseudoaneurysms, and fluid collections are other complications amenable to US evaluation. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.

Management of an aneurysmal arteriovenous fistula in kidney transplant recipients

Aneurysms remain the most common complication of an arteriovenous fistula created for dialysis access. The management of an aneurysmal arteriovenous fistula (AAVF) in kidney transplant recipients remains contentious with a lack of clear clinical guidelines. Recipients of a functioning graft do not require the fistula for dialysis access, however risk of graft failure and needing the access at a future date must be considered. In this review we outline the current evidence in the assessment and management of a transplant recipient with an AAVF. We will describe our recommended five-step approach to assessing an AAVF in transplant patients; 1.) Define AAVF 2.) Risk assess AAVF 3.) Assess transplant graft function and future graft failure risk 4.) Consider future renal replacement therapy options 5.) Vascular mapping to assess future vascular access options. Then we will describe the current therapeutic options and when they would most appropriately be employed.

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.

Standardized Methodology for Duplex Ultrasound Examination of Arteriovenous Access for Hemodialysis: A Proposal of the French Society of Vascular Medicine and the French-Speaking Society of Vascular Access

Duplex ultrasound (DUS) is an essential tool for characterizing and monitoring arteriovenous (AV) access for hemodialysis. The aim of the work described here, requested by the French Society of Vascular Medicine in collaboration with the French-Speaking Vascular Access Society, is to propose a standardized methodology for performing and documenting DUS, taking into account the variety of AV access techniques and the problems routinely encountered. A steering committee reviewed the literature and selected the relevant references. A draft was prepared, and all items with missing or conflicting data were submitted to a Delphi consensus. The final document was discussed and approved by all participants. The principles of DUS evaluation of AV access consist of examination of the afferent artery, the anastomosis and the entire venous drainage system. DUS uses B-mode ultrasound, color flow, pulsed wave and power Doppler analysis. DUS can be used in a variety of clinical situations, which can directly influence the methodology of the examination and the interpretation of the results. Blood flow should be assessed as it correlates with the risk of thrombosis. The measurement should be adapted to the different anatomical and hemodynamic conditions encountered. Characterization of stenosis should take into account the residual diameter of the drainage vein and its hemodynamic consequences. Other complications can be assessed with a standardized DUS examination. When performed according to a rigorous methodology, DUS of the AV access allows a comprehensive assessment of its functionality and eliminates the need for further invasive diagnostic procedures.

Surgical Referral for Hemodialysis Access Maintenance

Hemodialysis access is the lifeline for end-stage renal disease patients. However, dialysis access is associated with a host of complications, including thrombosis, recurrent stenosis, infection, aneurysmal changes and bleeding. Although endovascular therapy remains the first-line treatment owing to its less invasive nature, there are certain situations where surgical referral is recommended or even necessary. Regardless, management of dialysis access complications requires a multidisciplinary approach. Interventional radiologists should be familiar with the appropriate timing for surgical referral to better serve the complex patient population.

Manual compression technique improves the success rate in the treatment of thrombosed aneurysmal arteriovenous fistula: A single-center experience

OBJECTIVE

Endovascular intervention for thrombosed aneurysmal arteriovenous fistula (AVF) is still a challenge. Manual compression technique (MCT)-assisted angioplasty may be helpful, but there is no evidence or data to support it.

METHODS

From January 2018 to May 2021, patients with thrombosed aneurysmal AVFs were retrospectively enrolled. The patients were separated into the MCT group or the traditional group according to the procedure received. Technical failure, clinical failure, 90-day patency, and safety were analyzed.

RESULTS

A total of 159 cases (64 ± 12 years old, 60% male) were enrolled, of which 87 cases received MCT and 72 underwent traditional angioplasty. No technical failure was observed in the MCT group, while five technical failures were observed in the traditional group (0% vs. 7%, p = 0.02). There were no differences in the clinical failure rate (3% vs. 7%, p = 0.30), 90-day patency rate, or procedure time between the MCT group and the traditional group. There was no symptomatic pulmonary embolism or other complication in the two groups.

CONCLUSION

MCT is a low-cost, less invasive, and safe procedure for thrombosed aneurysmal AVF, and it achieves a higher technical success rate than traditional angioplasty.

Arteriovenous fistula aneurysmorrhaphy is associated with improved patency and decreased vascular access abandonment

BACKGROUND

Upper extremity hemodialysis arteriovenous fistulas (AVFs) can become aneurysmal over time due to repeated cannulation and/or outflow steno-occlusive disease. The optimal surgical management of aneurysmal AVFs (aneurysmorrhaphy vs interposition graft) has remained unclear.

METHODS

We performed a retrospective review in which current procedural terminology codes were used to screen for patients who had undergone surgical treatment of aneurysmal AVFs between 2016 and 2021 at a single hospital system. The patients were included after a review of the operative reports. The cases were divided by surgical procedure (aneurysmorrhaphy vs interposition graft placement). The patients who had undergone primary AVF ligation or other types of repair were excluded. The primary outcomes were primary assisted and secondary patency, and the secondary outcome was dialysis access abandonment. Multivariable Cox proportional hazards regression was used to test the association between the type of AVF aneurysm repair and the primary and secondary outcomes.

RESULTS

From 2016 to 2021, 6951 patients had undergone 16,190 dialysis access procedures. Of these procedures, 381 (2.4%) were related to surgical treatment of an aneurysmal AVF. We excluded 58 primary AVF ligation cases and 20 cases involving other types of repair, leaving 303 cases for analysis. These were divided into two groups: aneurysmorrhaphy (n = 123; 41%) and interposition graft (n = 180; 59%). No differences were found between the groups in male gender (68% vs 63%), hypertension (98% vs 98%), or central stenosis (14% vs 22%). The patients who had undergone aneurysmorrhaphy were younger (median age, 54 years vs 59 years); had had a lower rate of diabetes (41% vs 59%), coronary artery disease (41% vs 58%), and congestive heart failure (41% vs 55%); and were less likely to have undergone upper arm access (72% vs 92%). The median follow-up was 11.1 months (interquartile range, 3.6-25.2 months). No differences were found in the incidence of 30-day wound complications (1% vs 3%) or surgical site infections (4% vs 6%). On multivariable Cox regression, interposition graft placement was associated with the loss of primary assisted patency (adjusted hazard ratio [aHR], 2.42; 95% confidence interval [CI], 1.18-4.95), loss of secondary patency (aHR, 3.10; 95% CI, 1.21-7.94), and abandonment of dialysis access (aHR, 3.07; 95% CI, 1.61-5.87; P < .05 for all) at 2 years.

CONCLUSIONS

AVF aneurysmorrhaphy was associated with improved primary assisted and secondary patency and decreased abandonment of dialysis access. We suggest using aneurysmorrhaphy when AVF aneurysms are indicated for repair. However, individual factors such as patient comorbidities, AVF anatomy, remaining dialysis access options, and patient preference should be considered when planning the surgical approach.

A randomised control trial protocol of MuST for vascular access cannulation in hemodialysis patients (MuST Study): contributions for a safe nursing intervention

BACKGROUND

The vascular access preservation and the maintenance of a complication-free fistula remains an Achilles' heel of hemodialysis in chronic kidney patients due to its substantial contribution to the morbidity and mortality. Systematic studies in the area of examining cannulation practices, achieving complication-free cannulation, and strategies to improve fistula survival are needed. For this reason, we consider it essential to create and investigate new methodologies for approaching fistula in patients on regular HD. The Multiple Single Cannulation Technique (MuST) is based on the association between the rope-ladder (RL) using the arteriovenous vessel through progressive rotation, and the buttonhole (BH) since there are three specific cannulation sites for each cannulation day during the week. The MuST is simple to implement and seems to be a very promising technique in terms of patient safety. Previous studies already showed an arteriovenous fistula survival similar to RL but significantly higher than BH.

METHODS

This MuST study is a multicenter, prospective, non-blind, parallel-group, randomized controlled trial with the intervention group submitted to MuST and a control group undergoing the rope-ladder, up to 100 subjects for each group. Patients will be randomized 1:1 to one of two cannulation technique (CT), and the follow-up period of this study will be 12 months. Primary outcome is to evaluate the arteriovenous fistula survival rate at 12 months determined by the percentage of fistulas in use from the beginning of the study to the date of the first clinical intervention by angioplasty or vascular surgery, to maintain or restore patency (unassisted patency). Secondary outcome is to evaluate arteriovenous fistula survival rate at 12 month determined by the percentage of fistulas in use from the study start to the date of access abandonment due to dysfunction, patient abandonment, or death, treatment change modality or study end. We will also evaluate the assisted primary patency and include the following secondary outcomes associated with the cannulation technique: Infection, Hematoma, Aneurysm development, and pain.

DISCUSSION

The study will investigate whether fistula survival can be improved when using cannulation by MuST compared to the RL. MuST study will provide important information on fistula survival when cannulated by MuST but also information related to its use in fistulas previously cannulated by other CTs.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT05081648 registered on 18 October 2021.

Recanalization of thrombosed aneurysmal hemodialysis arterovenous fistulas using a hybrid technique based on data from a single center

Objective

To explore the technical specifications and clinical outcomes of thrombosed aneurysmal haemodialysis arteriovenous fistula (AVF) treated with ultrasound-guided percutaneous transluminal angioplasty combined with minimal aneurysmotomy.

Methods

This case series study included 11 patients who had thrombosed aneurysmal AVF and underwent salvage procedures over a 13-month period. All procedures were performed under duplex guidance. Minimal aneurysmotomy was performed, along with manual thrombectomy and thrombolytic agent infusion, followed by angioplasty to macerate the thrombus and sufficiently dilate potential stenoses. A successful procedure was defined as immediate restoration of flow through the AVF.

Results

The 11 patients (four males and seven females) had a mean age of 49.6 years ± 11.9 years. Six patients (54.5%) had two or more aneurysms. The mean aneurysm maximal diameter was 21.5 mm (standard deviation: ± 5.0 mm), and the mean thrombus length was 12.9 cm (8–22 cm). Ten (83.3%) of the 12 procedures were technically successful. The mean duration of operation was 150.9 minutes (standard deviation: ± 34.2 minutes), and mean postoperative AVF blood flow was 728.6 ml/min (standard deviation: ± 53.7 mi/min). The resumption of hemodialysis was successful in all 11 cases, with a clinical success rate of 100%. The primary patency rates were 90.0% and 75.0% at three and four months over a mean follow-up time of 6.3 months (3–12 months). The secondary patency rates were 90.4% at three and four months.

Conclusion

A hybrid approach combining ultrasound-guided percutaneous transluminal angioplasty and minimal aneurysmotomy might be a safe and effective method for thrombosed aneurysmal AVF salvage.

Surgical management of a giant venous aneurysm in an autogenous arteriovenous fistula with the vessel loop shoelace technique for wound closure: A case report

RATIONALE

Giant venous aneurysm (GVA) is a complication of chronic arteriovenous fistula (AVF). The risks of thrombosis, rupture, and massive hemorrhage increase with the increasing size of GVA; therefore, GVA requires treatment. However, the optimal timing and treatments are yet to be established.

PATIENT CONCERNS

A 51-year-old male patient who had been undergoing hemodialysis for 10 years using a left radio-cephalic AVF presented to the hospital with an enormous venous aneurysm.

DIAGNOSIS

Physical examination and ultrasound revealed a GVA in the AVF.

INTERVENTION

The aneurysm was resected, and autogenous AVF was concomitantly formed using the basilic vein. The large wound caused by the removed aneurysm defect was closed using the vessel loop shoelace technique.

OUTCOMES

The wound healed completely, and the patient has been undergoing hemodialysis using the autogenous AVF created during the surgery for 15 months since then.

LESSONS

Surgical treatment should be considered for symptomatic GVA. Concomitant aneurysm resection and autogenous AVF formation using the basilic vein may be performed, and the resulting large wound can be closed with the vessel loop shoelace technique to facilitate healing.

Cannulation Technique of Vascular Access in Haemodialysis and the Impact on the Arteriovenous Fistula Survival: Protocol of Systematic Review

BACKGROUND

Based on a literature review of various studies, comparisons between BH and RL are inconclusive regarding some outcomes. However, in the last 5 years, some studies have been published that may contribute to clarifying which cannulation technique (CT) allows better fistula survival.

AIM

To review which cannulation technique allows better primary patency of the arteriovenous fistula in haemodialysis patients.

METHODS

We will include all randomised controlled trials and observational studies that include comparisons among CTs and thus define the benefits and risks of each CT. A PRISMA-compliant systematic review and meta-analysis will be performed in accordance with the quality and homogeneity of studies. A comprehensive search strategy will be applied to the CINAHL, MEDLINE and Embase electronic databases from January 2000 to September 2021. The primary outcome is the arteriovenous fistula primary patency. To assess the risk of bias in randomised controlled trials or quasi-experimental studies, we will use the tool Revised Cochrane Risk-of-Bias Tool for Randomized Trials (RoB 2). For nonrandomised studies, the Risk of Bias In Non-Randomized Studies of Interventions (ROBINS-I) will be used.

DISCUSSION

The evidence generated from this systematic review of current evidence could inform the design and implementation of continuous quality improvement programs in cannulation techniques in haemodialysis patients, as well as contributing to improving the curricula within haemodialysis courses. This protocol was registered with the National Institute for Health Research PROSPERO database prior to commencement (registration number CRD42021237050).

To Close, Observe, or Reconstruct: The Third Way of Managing Dialysis Fistula Aneurysms in Kidney Transplant Recipients

Background: The management of patent dialysis fistulas in patients after kidney transplantation (KTx) is controversial—the options that are usually considered are the fistula’s closure or observation. Many complications of dialysis fistulas occur in patients after KTx, and immunosuppression increases the risk of fistula aneurysms and hyperkinetic flow. This study aimed to evaluate the results of dialysis fistula aneurysm treatment in patients after KTx and to compare them to procedures performed in an end-stage renal disease (ESRD) dialyzed population. Methods: We enrolled 83 renal transplant recipients and 123 ESRD patients with dialysis fistula aneurysms qualified for surgical revision to this single-center, prospective study. The results of the surgical treatment of dialysis fistula aneurysms were analyzed, and the primary, assisted primary and secondary patency rate, percentage and type of complications were also assessed. Results: For the treatment of dialysis fistula aneurysms in transplant patients, we performed dialysis fistula excisions with fistula closure in 50 patients (60.2%), excision with primary fistula reconstruction (n = 10, 12.0%) or excision with PTFE bypasses (n = 23, 27.7%). Postoperative complications occurred in 11 patients (13.3%) during a follow-up (median follow-up, 36 months), mostly in distant periods (median time after correction procedure, 11.7 months). The most common complication was outflow stenosis, followed by hematoma, dialysis fistula thrombosis and the formation of a new aneurysm and postoperative bleeding, infection and lymphocele. The 12-month primary, primary assisted and secondary patency rates of fistulas corrected by aneurysm excision and primary reconstruction in the KTx group were all 100%; in the control ESRD group, the 12-month primary rate was 70%, and the primary assisted and secondary patency rates were 100%. The 12-month primary, primarily assisted and secondary patency rates after dialysis fistula aneurysm excision combined with PTFE bypass were better in the KTx group than in the control ESRD group (85% vs. 71.8%, 90% vs. 84.5% and 95% vs. 91.7%, respectively). Kaplan–Meier analysis showed a significant difference in primary patency (p = 0.018) and assisted primary (p = 0.018) rates and a strong tendency in secondary patency rates (p = 0.053) between the KTx and ESRD groups after dialysis fistula excisions combined with PTFE bypass. No statistically significant differences in patency rates between fistulas treated by primary reconstruction and reconstructed with PTFE bypass were observed in KTx patients. Conclusions: Reconstructions of dialysis fistula aneurysms give good long-term results, with a low risk of complications. The reconstruction of dialysis fistulas can be an effective treatment method. Thus, this is an attractive option in addition to fistula ligation or observation in patients after KTx. Reconstructions of dialysis fistula aneurysms enable the preservation of the dialysis fistula while reducing various complications.

Role of Doppler ultrasonography in the evaluation of hemodialysis arteriovenous access maturation and influencing factors

The goal of vascular access creation is to achieve a functioning arteriovenous fistula (AVF) or arteriovenous graft (AVG). An autologous fistula has been shown to be superior to AVG or to central venous catheters (CVCs) with lowest rate of re-intervention, but vessel obstruction or immaturity accounts for 20 % to 54% of cases with primary failure of AVF. This review is focused on the factors influencing maturation; indication and timing of preoperative mapping/creation of vascular access; ultrasound parameters for creation AVF/AVG; early postoperative complications following creation of a vascular access; ultrasound determinants of fistula maturation and endovascular intervention in vascular access with maturation failure. However, vascular accesses that fail to develop, have a high incidence of correctable abnormalities, and these need to be promptly recognized by ultrasonography and managed effectively if a high success rate is to be expected. We review approaches to promoting fistula maturation and duplex ultrasonography (DUS) of evaluating vascular access maturation.

Multiple single cannulation technique of arteriovenous fistula: A randomized controlled trial

Introduction

Despite the impact needling has had on vascular access survival and patient outcome, there is no universal or standardized method proposed for proper cannulation. Rigorous studies are needed, examining cannulation practices, and challenges to achieving complication‐free cannulation.

Methods

This randomized, open‐label trial was conducted at 18 dialysis units owned by a large private dialysis provider operating in Portugal. Eligible patients were adults on chronic hemodialysis, with a new arteriovenous fistula (AVF); cannulated for at least 4 weeks complication‐free. Patients were randomly assigned in a 1:1 ratio to one of three cannulation techniques (CT): Multiple Single cannulation Technique (MuST), rope‐ladder (RLC), and buttonhole (BHC). The primary endpoint was AVF primary patency at 1 year.

Findings

One hundred seventy‐two patients were enrolled between March 2014 and March 2017. Fifty‐nine patients were allocated to MuST, 56 to RLC, and 57 to BHC.

MuST and RLC were associated with a better AVF primary patency than BHC. Primary patency at 12 months was 76.3% in MuST, 59.6% in BHC, and 76.8% in RLC group. Mean AVF survival times were 10.5 months (95% CI = 9.6, 11.3) in the MuST group, 10.4 months (95% CI = 9.5, 11.2) in RLC, and 9.5 months (95% CI = 8.6, 10.4) in BHC. BHC was a significant risk predictor for AVF survival with 2.13 times more events than the other two CT (HR 2.13; 95% CI = 1.07, 4.21; p = 0.03).

Discussion

MuST was easy to implement without a diagram and there is no need to use blunt needles. This study showed MuST was efficacious and safe in maintaining the longevity of AVF in dialysis patients.

Arterial diameter following arteriovenous fistula creation predicts aneurysm progression

OBJECTIVE

To investigate the relationship between arteriovenous fistula (AVF) arterial diameter (AD) and AVF aneurysm development and progression.

METHODS

This study identified all patients who underwent fistulograms which demonstrated AVF aneurysms meeting criteria and requiring surgical intervention between 01/01/2014 and 7/30/2016. Patient demographics were collected and AVF dimensions were measured on fistulograms. A control group with nonaneurysmal AVFs who had undergone serial fistulograms between 2013 and 2016 were identified and identical datasets collected. Statistical analysis was performed with STATA 14.0 using student's t-test, Chi square tests and linear regression.

RESULTS

45 eligible patients were identified in the AVF aneurysm study group and 24 in the control group, with the mean age of AVF creation being older in the control group (61.8 vs 53 years, p = 0.03). The mean interval between AVF creation and first fistulogram in the study group was 1464 ± 282 days, compared to an interval of 263 ± 101 days in the control group (p = 0.003). The AD on the first fistulogram in those study group patients with aneurysms evident on first fistulogram was greater than in the control group (6.5±1.8 mm vs 5.0 ± 1.8 mm, p = 0.003). The AD on first fistulogram of the study group predicted maximum aneurysm diameter on last fistulogram (r = 0.6, p = 0.03) as well as the interval between first fistulogram and surgical revision (r = -0.33, p = 0.03).

CONCLUSION

AVF aneurysms are a later complication in access natural history and AD may help to predict their progression.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

Aneurysm Excision With Arteriovenous Anastomosis Proximalization for Dialysis Fistula Aneurysm Treatment

INTRODUCTION

Dialysis fistula aneurysms are common complications, which require surgical revision in selective cases. The results of aneurysm excision with arteriovenous anastomosis proximalization for the treatment of dialysis fistula aneurysms have been described below.

METHODS

Patients qualified for the reconstruction of a dialysis fistula aneurysm underwent a duplex ultrasound examination. The diameter, length of the aneurysm, relations with the artery, thrombus presence and blood flow were determined. In the case of favorable anatomical conditions, we performed aneurysm excision with arteriovenous anastomosis proximalization as the procedure of choice. Patients, dialysis access, operative data and the results obtained during a median follow-up of 41 months were then analyzed.

FINDINGS

Since 2012, we have performed 20 aneurysm excision combined with primary anastomosis as dialysis fistula aneurysm treatment. In 18 patients, aneurysm excision was combined with simple re-anastomosis in the more proximal arterial segment. In 2 autogenous radio-cephalic forearm direct fistulas the aneurysm excision was combined with switching anastomosis type from side-to-end to end-to-end. The 12- and 24-month primary patency rates of corrected fistulas in the observed group were 94.7% and 82.4%, respectively. No early complications were noted. In 7 patients (35%) we observed late complications, which required reintervention or led to access failure. Dialysis fistula thrombosis as an indication for treatment was a significant risk factor for late re-occlusion.

DISCUSSION

A simple primary reconstruction by arteriovenous anastomosis proximalization and aneurysm excision for the surgical correction of dialysis fistula aneurysms has potential benefits compared to established methods-aneurysmorraphy and aneurysm excision with a vascular prosthesis bypass. The obtained data showed the efficiency, safety and excellent long-term results of this procedure.

Determining the incidence of needle-related complications in hemodialysis access: We need a better system

INTRODUCTION

Hemodialysis access complications are common. We hypothesize that many of these complications can be traced back to needle-related injury from routine cannulation practices or inadvertent cannulation injuries. We set out to compare the rates of hemodialysis access complications under prior and current diagnosis coding systems, determine the incidence of needle-related complications for hemodialysis access, and describe the association of needle-related complications and resulting interventions.

METHODS

Arteriovenous graft and arteriovenous fistula placements occurring in the first 6 months of 2014 and 2016 were identified in the United States Renal Data System Medicare claims data. Placements were followed until end of hemodialysis access life or end of the calendar year. Diagnoses and resulting interventions occurring during placement life were identified and mapped to needle-related complication terms.

RESULTS

Almost 30,000 placements for 27,000 patients were followed in each year, with 67% of all accesses placed being arteriovenous fistula and 33% arteriovenous graft. In both years, 75% of arteriovenous fistulae and arteriovenous grafts required one or more interventions. Stenosis and thrombosis were the most common complications diagnosed and treated (41% and 16%, respectively); however, potential needle-related complications accounted for 6% of this dataset.

DISCUSSION

International Classification of Diseases, 9th Revision, was inadequate for determining the incidence of specific hemodialysis access complications or needle-related complications. International Classification of Diseases, 10th Revision, introduced several more hemodialysis access diagnoses but is still subject to coding confusion and catch-all coding for a variety of common and otherwise well-defined complications, suggesting that the true incidence of needle-related complications is buried in the non-specific diagnosis codes. These findings mark the clear need for an improved diagnosis coding system that consistently represents all common hemodialysis access complications.

Hybrid procedures in the dialysis fistula aneurysm treatment

OBJECTIVES

Dialysis fistula aneurysms are common complications which in selective cases require surgical revision. It is recommended to detect and treat outflow stenosis concurrent with a dialysis fistula aneurysm, but usually, the treatment is divided into two stages - the open and endovascular stages are performed separately. We describe the results of hybrid procedures composed of aneurysm resection and endovascular correction for outflow veins performed for a dialysis fistula aneurysm treatment.

METHODS

From March 2012, we performed hybrid procedures in 28 patients to correct dialysis fistula aneurysms. Patients, dialysis access, operative data, and the results obtained during a median follow-up of 28.5 months were analyzed.

RESULTS

For dialysis fistula aneurysm correction, we performed 27 bypasses and 1 aneurysmorraphy. For outflow vein stenosis correction, we performed standard balloon angioplasty, no stents or stentgraft were used. The average increase in minimal diameter after angioplasty was 135.5% (range 57-275%). The 12- and 24-month primary patency rates of corrected fistulas in the observed group were 92.3% and 80%, respectively. A significant difference in the one-year patency rates between the urgent and planned procedures was observed (81.2% vs. 100%, respectively). No early complications related to endovascular or open procedures were observed. Late complications were observed in seven patients (25%) - mainly thrombosis caused by the recurrence of outflow vein stenosis (six patients, 21.5%), infection, lymphocele, and hematoma (one case of each complication).

CONCLUSIONS

A hybrid procedure for the surgical correction of dialysis fistula aneurysms with the simultaneous correction of outflow pathologies enables effective long-term treatment. The obtained data showed the efficiency and good results of this procedure. Procedures performed for urgent indications significantly increase the risk for later complications, especially fistula thrombosis and loss of dialysis access.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Stent graft deployment in haemodialysis fistula: patency rates in partially thrombosed aneurysm and residual thrombi

Background

Current evidence is insufficient to determine the contribution of stent grafts as treatment in partially thrombosed aneurysms or residual wall-adherent thrombi in arteriovenous fistulae (AVFs) for haemodialysis. The overall purpose of this study was to analyse patency rates of post-interventional covered stent deployment in those cases. We also assessed if patency rates differed when fistulas were punctured through the stent during dialysis sessions.

Methods

We conducted a retrospective study between 2006 and 2014 analysing post-intervention primary patency rates using the Kaplan-Meier log-rank test. Multivariate Cox proportional regression models were performed to determine if cannulation within the stent graft area was a potential risk factor for occlusion, by adjusted hazard ratio (HR).

Results

A total of 27 procedures were included in the study. Primary patency rates (%) after stent deployment at 3, 6, 12, 24, 36 and 72 months were, respectively: total 59, 32, 32, 21, 11 and 5; stent puncture 53, 21, 21, 16, 5 and 0; and no stent puncture 80, 80, 80, 40, 40 and 40. Cannulation through the stent graft was not significantly associated with increased risk of obstruction in multivariate analysis (HR = 3.01; P = 0.286).

Conclusion

Stent graft treatment may be a feasible procedure in partially thrombosed aneurysms and residual thrombi in AVF. Although fistulas punctured through the stent presented lower patency rates, this practice was not associated with a higher risk of obstruction. Giving the impossibility of comparing with similar approaches, further studies are needed to confirm or refute the advantages of this procedure.

[Conservative aneurysmorrhaphy for hemodialysis arteriovenous fistula]

The aim of this study was to evaluate the results of conservative surgical treatment of the aneurysmal complications of arteriovenous hemodialysis fistulae and to determine the factors predictive of long- and mid-term patency of treated fistulae. The surgical treatment was mainly based on caliber reduction and reconstruction.

METHODS

This was a descriptive retrospective study with a five-year duration, going from January 2013 to December 2018. This study included 40 patients presenting aneurysmal complications of their hemodialysis vascular access who were treated with aneurysmorrhaphy.

RESULTS

The mean age of the aneurysmal-complicated hemodialysis vascular access was 42 months. The indications for treatment were puncture-related difficulties in 42.5% of cases, rapid increase of the aneurysmal diameter in 27.5%, skin thinning in 25% and aneurysmal rupture in 5%. The mean aneurysmal course was 6.6 months with an average diameter of 3.25cm at the moment of management. The initial technical success rate was 100%. Twenty patients had complications in the postoperative period. Patency rates at 3, 6, 12 and 24 months were 89.5%, 81.6%, 71% and 63.1%, respectively. Factors predictive of thrombosis were diabetes (P=0.001), peripheral arterial disease (P=0.003), number of punctures per week (P=0.003) and context of emergency presentation (P=0.001).

CONCLUSION

Aneurysmorrhaphy seems to be the best conservative surgical treatment for aneurysmal complications of hemodialysis vascular access fistulae. This surgical approach allows us to conserve the native autologous vascular access and spare the patient's venous network.

Giant brachial artery aneurysm as a rare complication of a dialysis shunt

Our patient exhibited a large tumor on his right upper arm where his former dialysis access site had been. X-ray, Doppler ultrasound, and magnetic resonance imaging scan could not fully reveal the nature of that tumor. Eventually, a surgical approach showed a giant aneurysm of the inflowing brachial artery to a partially obliterated arteriovenous fistula. This case highlights the importance of ongoing care for patients with arteriovenous shunts. Even arteriovenous fistulas, that are obliterated or no longer in use, can, especially when immunosuppressant therapy and other vascular risk factors are added to the overall cardiovascular risk, transform and endanger the health of our patients.

Endoscopic Superficialisation of Haemodialysis Arteriovenous Fistulas in Obese Patients - Safety, Feasibility, and Outcomes

OBJECTIVE

The aim was to evaluate the safety and feasibility of endoscopic superficialisation (ES) in patients with deeply located cephalic veins in well matured arteriovenous fistulae (AVF) and to present functional outcomes.

METHODS

All patients with cannulation difficulties due to a deep lying cephalic vein of more than 6 mm but with an otherwise matured AVF with a straight needle access segment of at least 6 cm were included in this retrospective study. Procedure related safety, defined as completion of ES with no need for conversion to open surgery, and feasibility in terms of cephalic vein depth reduction were assessed. The primary endpoint was three successfully performed haemodialysis sessions using the endoscopically superficialised AVF during a minimum follow up of 12 months.

RESULTS

From June 2013 to August 2017, 12 patients with a mean body mass index of 33.5 ± 3.9 kg/m² underwent ES as a second stage procedure following radiocephalic (n = 5) or brachiocephalic AVF (n = 7) creation. All procedures were conducted endoscopically. Ultrasound imaging 12 weeks post-operatively documented a reduction in the depth of the cephalic vein from a mean of 10.1 ± 1.4 mm to 4.3 ± 0.8 mm. The mean duration of the ES was 69 ± 26.0 min with 67% performed under locoregional anaesthesia. In all but one patient with a cephalic vein of poor wall quality leading to recurrent haematoma, haemodialysis was performed successfully following ES.

CONCLUSIONS

Endoscopic superficialisation of the cephalic vein is a safe and effective technique. Providing good functional results, ES represents an alternative approach for second stage superficialisation in obese patients.

Partial aneurysmectomy for treatment of autologous hemodialysis fistula aneurysm is safe and effective

OBJECTIVE

The purpose of this study was to evaluate the outcome and the factors associated with stenosis after treatment using partial aneurysmectomy for aneurysm in autologous arteriovenous fistulas.

METHODS

This retrospective cohort study was conducted from July 2007 to June 2016 and included patients with complicated aneurysms in upper extremity autologous arteriovenous fistulas were treated by partial aneurysmectomy. Vascular ultrasound examination was performed every 6 months after the surgery.

RESULTS

Forty-one patients (median age, 37 years; 70.7% males) were included. Of the patients, 95.1% had a radial-cephalic fistula in the forearm and nearly 88% had 1 or 2 aneurysms in arteriovenous fistulas that had been created for 10 to 84 months. Technical success of partial aneurysmectomy was achieved in all patients. The access diameter (44.0 ± 5.1 mm vs 10.4 ± 1.8 mm; P < .01) and brachial artery blood flow (1618.2 ± 277.0 mL/min vs 772.1 ± 127.4 mL/min; P < .01) were significantly decreased after the surgery. The median follow-up time was 27 months (range, 12-43 months). The primary patency rates at 6 and 12 months were 100% and 95%, respectively. Loss of patency was due to stenosis of the remodeled fistulas, which occurred in seven patients (17%). Multivariate COX regression analysis revealed that diabetes (hazard ratio, 114.28; 95% confidence interval, 2.85-4583.94; P = .01) was a risk factor for the impaired primary patency rates. A larger postprocedure residual diameter trended to favor fistula patency (hazard ratio, 0.46; P = .07). Stenosis was successfully treated with percutaneous transluminal angioplasty.

CONCLUSIONS

Partial aneurysmectomy is an effective and safe method for treating aneurysm of upper extremity autologous arteriovenous fistulas, leading to good 12-month primary patency and no aneurysm recurrence. Using a larger catheter to size the revised fistula during aneurysmectomy may increase access patency.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

A Report of Two Cases of Hazards Associated with High Flow Arteriovenous Fistula in ESRD Patients

High flow arteriovenous fistulas are a common clinical entity affecting patients with end-stage renal failure receiving hemodialysis. Given the difficulty in predicting who will develop a high flow arteriovenous fistula the exact prevalence is unclear. We present two cases of patients with high flow arteriovenous fistula that developed clinical cardiac failure at a time point after the fistula was placed with findings of significant cephalic arch stenosis. Both patients required treatment of cephalic arch stenosis with balloon angioplasty with subsequent surgical aneurism resection. Accurate and timely diagnosis of high flow arteriovenous hemodynamics by prospective monitoring of volumetric flow and cardiac function is required to halt this process prior to cardiac compromise.

Definitions and End Points for Interventional Studies for Arteriovenous Dialysis Access

This paper is part of the Clinical Trial Endpoints for Dialysis Vascular Access Project of the American Society of Nephrology Kidney Health Initiative. The purpose of this project is to promote research in vascular access by clarifying trial end points which would be best suited to inform decisions in those situations in which supportive clinical data are required. The focus of a portion of the project is directed toward arteriovenous access. There is a potential for interventional studies to be directed toward any of the events that may be associated with an arteriovenous access' evolution throughout its life cycle, which has been divided into five distinct phases. Each one of these has the potential for relatively unique problems. The first three of these correspond to three distinct stages of arteriovenous access development, each one of which has been characterized by objective direct and/or indirect criteria. These are characterized as: stage 1-patent arteriovenous access, stage 2-physiologically mature arteriovenous access, and stage 3-clinically functional arteriovenous access. Once the requirements of a stage 3-clinically functional arteriovenous access have been met, the fourth phase of its life cycle begins. This is the phase of sustained clinical use from which the arteriovenous access may move back and forth between it and the fifth phase, dysfunction. From this phase of its life cycle, the arteriovenous access requires a maintenance procedure to preserve or restore sustained clinical use. Using these definitions, clinical trial end points appropriate to the various phases that characterize the evolution of the arteriovenous access life cycle have been identified. It is anticipated that by using these definitions and potential end points, clinical trials can be designed that more closely correlate with the goals of the intervention and provide appropriate supportive data for clinical, regulatory, and coverage decisions.

Randomized pilot study to compare metal needles versus plastic cannulae in the development of complications in hemodialysis access

BACKGROUND

Hemodialysis requires needle insertions every treatment. Needle injury (mechanical or hemodynamic) may cause complications (aneurysms/stenosis) that compromise dialysis delivery requiring interventions. Metal needles have a sharp slanted "V"-shaped cutting tip; plastic cannulae have a dull round tip and four side holes. Preliminary observations demonstrated a difference in intradialytic blood flow images and mean Doppler velocities at cannulation sites between the two devices. Complications from mechanical and hemodynamic trauma requiring interventions were compared in each group.

MATERIALS AND METHODS

In all, 33 patients (13 females and 17 new accesses) were randomized to metal group (n = 17) and plastic group (n = 16). Mechanical trauma was minimized by having five nurses performing ultrasound-guided cannulations. Complications were identified by the clinician and addressed by the interventionalists, both blinded to study participation. Patients were followed for up to 12 months.

RESULTS

Baseline characteristics were not significant. Procedures to treat complications along cannulation segments increased from 0.41 to 1.29 per patient (metal group) and decreased from 1.25 to 0.69 per patient (plastic group; p = 0.004). The relative risks of having an intervention (relative risk = 1.5, 95% confidence interval = 0.88-2.67) and having an infiltration during hemodialysis (relative risk = 2.26, 95% confidence interval = 1.03-4.97) were higher for metal needles. Time to first intervention trended in favor of plastic cannula (p = 0.069). Cost of supplies for these interventions was approximately CAD$20,000 lower for the plastic group.

CONCLUSION

Decreased burden of illness related to cannulation (less infiltrations during hemodialysis) and Qb were associated with plastic cannulae. Decreased procedure costs were suggested during the study period in the plastic group.

Aneurysms in Vascular Access: State of the Art and Future Developments

A master class was held at the Vascular Access at Charing Cross (VA@CX2017) conference in April 2017 with invited experts and active audience participation to discuss arteriovenous (AV) vascular access aneurysms, a serious and common complication of vascular access (VA). The natural history of aneurysms in VA is poorly defined, and although classifications exist they are not uniformly applied in studies or clinical practice. True and pseudo aneurysms of AV access occur. Whilst an AV fistula by definition is an abnormal dilatation of a blood vessel, an agreed definition of 18 mm, or 3 times accepted maturation diameter, is proposed. The mechanism of aneurysmal dilatation is unknown but appears to be a combination of excessive external remodeling, wall changes due to injury, and obstruction of outflow. Diagnosis of AV aneurysms is based on physical examination and ultrasound. Venography and cross-sectional imaging may assist and be required for the investigation of outflow stenosis. Treatment of pseudo aneurysms and true aneurysms of VA (AVA) is not evidence-based, but relies on clinical experience and available facilities. In many AVA, a conservative approach with surveillance is suitable, although intervals and modalities are unclear. Avoidance of rupture is imperative and preemptive treatment should aim for access preservation, ideally with avoidance of prosthetic materials. Different techniques of aneurysmorrhaphy are described with good results in published series. Although endovascular approaches and stenting are described with good short-term results, issues with cannulation of stented areas occur and, while possible, this is not recommended, and long-term access revision is recommended.

Impact of Needles in Vascular Access for Hemodialysis

This article reviews pragmatic aspects of cannulation practice and types of cannulation devices, as well as their impact in vascular access for hemodialysis. Hemodialysis treatment requires successful insertion of two needles for each dialysis treatment. The first needle is the arterial needle; it removes blood with toxin accumulation from the patient and delivers it to the dialysis machine. The second needle, called the venous needle, returns the purified blood from the dialyzer to the patient. Mechanical and hemodynamic trauma related to needle insertions will be discussed.

Cardiac remodeling after reduction of high-flow arteriovenous fistulas in end-stage renal disease

In patients with end-stage renal disease, excessive blood flow through an arteriovenous fistula (AVF) may lead to volume overload-induced cardiac remodeling and heart failure. It is unclear which patients with hyperfunctional AVF may benefit from AVF reduction or ligation. The indication for the procedure is often based on AVF flow. Because cardiac remodeling is driven by increased venous return, which is equivalent to cardiac output, we hypothesized that an elevated cardiac index (CI) might better identify subjects with reverse remodeling after AVF reduction. Thirty patients (age 52±12 years, 73% male) with AVF flow ⩾1.5 l min(-1) underwent comprehensive echocardiographic evaluations before and after AVF reduction. At baseline, 16 patients had a normal CI (2.5-3.8 l min(-1) m(-2)) and 14 had a high CI (4.0-6.0 l min(-1) m(-2)). A left ventricular end-diastolic diameter decrease after operation was predicted by elevated baseline CI (P<0.01), but not elevated AVF flow (P=0.07). There was a significant decrease in CI, left ventricular mass, left atrial and right ventricular diameter and pulmonary systolic pressure in the high CI group but not in the normal CI group. After AVF reduction, systemic vascular resistance decreased in the normal CI group, whereas it did not change in the high CI group. In conclusion, reduction of high-flow AVF leads to reverse cardiac remodeling but only in patients with elevated CI. The variability of the response of systemic vascular resistance to AVF flow may explain this observation. Increased CI but not increased AVF flow may better determine candidates for AVF reduction.