The arteriovenous fistula (AVF), a surgically created connection between an artery and a vein, remains the gold standard for vascular access in patients undergoing chronic hemodialysis. The fistula is most commonly created on the upper limb, where, for example, the cephalic vein and radial or brachial artery can be used. Although AVF is the most common method used for vascular access in hemodialysis, its performance remains vulnerable to multiple sources of potential failure. An arteriovenous fistula aneurysm (AVFA) in particular is one of the most common pathologies that develops in the vein segment of the anastomosis. The causes leading to AVFA formation are not yet fully understood. With this study, we wish to contribute to expanding our knowledge of AVFA biomechanics. Samples of healthy cephalic veins and aneurysmatic AVFs were collected from human donors. Uniaxial tensile tests in two perpendicular directions were carried out to determine their mechanical response. A significant decrease in the initial Young’s elastic modulus and anisotropy was observed in the AVFA group. Histological analysis of the samples showed a degradation of the elastic component and a disorganization of the collagen and VSMC. A 4-fiber-family hyperelastic anisotropic constitutive model of the exponential type was used in the nonlinear regression of the experimental data. The resulting constitutive models led to a good correspondence between the data and predictions. The obtained estimates of the constitutive parameters can be used in future fluid-structure interaction analyses aimed at computational simulations of AVF and AVFA hemodynamics.

OBJECTIVE:There is a lack of information and consistency in the treatment of retroperitoneal malignancy involving the inferior vena cava (IVC). The aim of this study was to establish an expert consensus on the surgical management of tumours involving the IVC. METHODS:Fourteen experts participated in this three round Delphi project. The survey was conducted from 1 January 2023 to 15 December 2023. RESULTS:All experts completed the first round, and the response rates in the second and third rounds were 92% and 86%, respectively. Consensus was reached on several key points. Abdominal computed tomography (CT) was identified as the gold standard imaging method for assessing tumours invading the IVC. CT guided core needle biopsy was preferred for tissue sampling. Experts agreed that the suprarenal IVC should be reconstructed, whereas a chronically occluded IVC with intact collateral circulation should not. Thrombectomy was indicated for malignant thrombi not involving the vessel wall; otherwise, IVC resection was recommended. A ringed expanded polytetrafluoroethylene prosthesis was the preferred graft material for interposition. Use of an IVC filter to prevent tumour embolisation and the creation of an arteriovenous fistula after IVC resection were not recommended. Post-operative thrombosis prevention should include therapeutic heparinisation and a mechanical compression device, and routine post-operative CT angiography was recommended. CONCLUSION:Based on scarce data from the literature and experience of international experts, this document will help clinicians in the decision making process when planning the treatment of retroperitoneal tumours involving the IVC.

Aneurysm formation is a complication of the use of arteriovenous fistulas, and symptomatic aneurysms require surgical treatment. The optimum treatment is aneurysmorrhaphy, because this salvages the function of the fistula. Aneurysmorrhaphy outcomes may be improved by implanting an external prosthesis over the repaired aneurysm. This study aimed to compare aneurysmorrhaphy performed with and without an external prosthesis. This was a multicenter, randomized, prospective non-blinded study. Patients with symptomatic aneurysms of arteriovenous fistulas were recruited between February 2018 and September 2022. Recruited patients were assigned randomly to undergoing aneurysmorrhaphy with or without an external prosthesis. The study compared patency and aneurysm recurrence rates at 1-year follow-up. Forty-six patients underwent aneurysmorrhaphy with an external prosthesis and fifty-five underwent aneurysmorrhaphy without an external prosthesis. There were no differences in patient and aneurysm characteristics between the two groups. At 1 year follow-up, the patency rates were 86% for aneurysmorrhaphy with external prosthesis and 80% for aneurysmorrhaphy without external prosthesis (p = 0.87). Aneurysm recurrences occurred in 2 patients (4.3%) who underwent aneurysmorrhaphy with external prosthesis and in 6 patients (10.9%) who underwent aneurysmorrhaphy without external prosthesis (p = 0.114). There was no statistically significant difference in primary patency rates and aneurysm recurrence between patients treated with aneurysmorrhaphy with and without external prosthetic support.

Vascular access-induced limb ischaemia is a potentially severe complication. A classification system for clinical assessment and treatment would be a useful clinical tool for standardising management. There are several classifications described in the current literature using inconsistent terminology. The aim of this review is to identify all the reported classification systems of vascular access-induced limb ischaemia and to present a comprehensive summary. PubMed, Scopus, Web of Science, Google Scholar and the ClinicalTrials.gov registry were searched from inception to the 17th of October 2024. All articles containing newly proposed classifications regarding haemodialysis vascular access were eligible. There were no restrictions to the full text's language or the type of study. The classifications were evaluated using a modified Buchbinder's classification critical appraisal tool. From 4694 screened papers, 59 full-text papers were retrieved, and eight articles contained classifications based only on the severity of vascular access-induced limb ischaemia. According to the modified Buchbinder critical appraisal, the classifications identified were overall good quality. The systems are all based on clinical symptoms but use inconsistent terminology and do not consider various aetiologies. We present a summary and propose a unified classification based on the anatomical location of the pathology, which leads to high- or low-flow ischaemia, along with a suitable therapeutic approach for each type.

The Arteriovenous Access Stage (AVAS) classification simplifies information about suitability of vessels for vascular access (VA). It’s been previously validated in a clinical study. Here, AVAS performance was tested against multiple ultrasound mapping measurements using machine learning. A prospective multicentre international study (NCT04796558) with patient recruitment from March 2021-July 2024. Demographics, risk factors, vessels parameters, types of predicted and created VA (pVA, cVA) were collected. We modelled pVA and cVA using the Random Forest algorithm. Model performance was estimated and compared using Bayesian generalized linear models. ROC AUC with 95% credible intervals was the performance metric. 1151 patients were included. ROC AUC for pVA prediction by AVAS was 0.79 (0.77;0.82) and by mapping was 0.85 (0.83;0.88). ROC AUC for cVA prediction by AVAS was 0.71 (0.69;0.74) and by mapping was 0.8 (0.78;0.83). Using AVAS with other parameters increased the ROC AUC to 0.87 for pVA (0.84;0.89) and 0.82 (0.79;0.84) for cVA. Using mapping with other parameters increased the ROC AUC to 0.88 for pVA (0.86;0.91) and 0.85 (0.83;0.88) for cVA. Multiple mapping measurements showed higher performance at VA prediction than AVAS. However, AVAS is simpler and quicker, so may be preferable for routine clinical practice.

StopBac is an innovative silver-impregnated antimicrobial dressing specifically designed to reduce surgical site infections and enhance healing. The primary objective of this study was to compare infection healing rate at 30 days after surgery between primarily closed surgical wounds covered with StopBac and those covered with Cosmorpor, a standard surgical dressing. Between 1.3.2023 and 30.4.2023, we conducted a prospective screening of all patients undergoing surgical operations within a single surgical department. Patients were randomised into either the Cosmopor group or the StopBac group. Outcome measures were superficial and deep surgical site infections and healed wounds. Data concerning patient and surgical factors were prospectively collected and analysed. The analysis comprised 275 patients, divided into two groups: 140 patients in the StopBac group and 135 in the Cosmopor group. The StopBac dressing was associated with a reduced rate of infection, with an odds ratio of 0.288 (p < 0.001), and an increased likelihood of wound healing at 30 days after surgery. The odds ratio for healing at 30 days was 4.661 (p < 0.001). StopBac was associated with a lower incidence of surgical wound infections and a higher probability of healing at 30 days after surgery, when compared with standard dressing.

Background The arteriovenous access stage (AVAS) classification provides evaluation of upper extremity vessels for vascular access (VA) suitability. It divides patients into classes within three main groups: suitable for native fistula (AVAS1) or prosthetic graft (AVAS2), and patients not suitable for conventional native or prosthetic VA (AVAS3). We validated this system on a prospective dataset.Methods A prospective, international observational study (NCT04796558) involved 11 centres from 8 countries. Patient recruitment was from March 2021 to January 2024. Demographic data, risk factors, vessels parameters, VA types, AVAS class and early VA failure were collected. Percentage agreement was used to assess predictive ability of AVAS (comparison of AVAS and created VA) and consistency of AVAS assessment between evaluators. Pearson's Chi-squared test was used for comparison of early failure rate of conventional (predicted by AVAS) and unconventional (not predicted by AVAS) VA.Results From 1034 enrolled patients, 935 had arteriovenous fistula or graft, 99 patients did not undergo VA creation due opting for alternative renal replacement therapies, experiencing health complications, death or non-compliance. AVAS1 had 91.2%, AVAS2 7.2% and AVAS3 1.6% of patients. Agreement between evaluators was 89%. The most frequently created VAs were radial-cephalic (46%) and brachial-cephalic (27%) fistulae. The accuracy of AVAS versus created access was 79%. In comparison, VA predicted by clinicians versus created access was 62.1%. Inaccuracy of AVAS prediction was more common with higher AVAS classes, and the most common reason for inaccuracy was creation of distal VA despite less favourable anatomy (17%). Patients with unconventional VA had higher early failure rate than patients with conventional VA (20% vs 9.3%, respectively, P = .002)Conclusion AVAS is effective in predicting VA creation, but overall accuracy is reduced at higher AVAS classes when the complexity of decision-making increases and proximal vessels require preservation. When AVAS was followed by clinicians, early failure was significantly decreased. Graphical Abstract

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.

Background: VAVASC study (Validation of Arterio Venous Access Stage Classification) is a multicentre, international, prospective study. The study aims to validate the AVAS classification, which is a classification system describing vascular status of patients indicated for creation of arteriovenous access on the upper limb. Methods: Observational, prospective, multicentre, international study starting in March 2021. Participant recruitment has commenced. Basic demographic data, risk factors and vascular mapping parameters are collected via an online platform. The outcome measures are class of AVAS, predicted arteriovenous access, final arteriovenous access that has been created and a functionality of the arteriovenous access. Predictive models will be used for statistical analysis. Current status: A total of 140 patients from 4 centres in Great Britain, Czech Republic, Brazil and Slovakia are already included and undergoing evaluation. Conclusions: The study is registered in the Clinical trials registry (NCT04796558), https://register.clinicaltrials.gov/ . Study is still open for collaboration with other centres that can register via www.vavasc.com .

Introduction: Portomesenteric vein resections are a well-established part of pancreatec-tomies for advanced tumors that invade the portomesenteric axis. There are two main types of portomesenteric resections: partial resections, where only part of the venous wall is removed and segmental resection, where the full circumference of the wall is removed. The aim of this study is to compare short-term and long-term outcomes between these two techniques.Methods: This is a single-centre retrospective study of the patients with pancreatic cancer who underwent pancreatectomy with portomesenteric vein resections between November 2009 and May 2021.Results: From a total of 773 pancreatic cancer procedures, 43 (6%) patients underwent pancreatectomy with portomesenteric resections: 17 partial and 26 segmental. The overall median survival was 11 mo. For the partial portomesenteric resections, the median sur-vival was 29 mo, and for the segmental portomesenteric resections, it was 10 mo (P = 0.019). The primary patency of the reconstructed veins after partial resection was 100% and after segmental resection was 92% (P = 0.220). Negative resection margins were ach-ieved in 13 patients (76%) who underwent partial portomesenteric vein resection and 23 patients (88%) who underwent segmental portomesenteric vein resection.Conclusions: |Although this study is associated with worse survival, segmental resection is often the only way to safely remove pancreatic tumors with negative resection margins.(c) 2023 Elsevier Inc. All rights reserved.

Objective: The goal of this study was to compare the cyanoacrylate venous sealing systems VenaSeal (TM) and VariClose (R) in the treatment of superficial venous insufficiency. Methods: A single-centre retrospective analysis on patients treated between April 2018 and April 2022 with cyanoacrylate adhesives for lower limb superficial truncal vein insufficiency was performed. Results: The VariClose (R) system was used in 27 patients (30 veins) and the VenaSeal (TM) system in 97 patients (125 veins). The median follow-up periods for patients treated with VariClose (R) and VenaSeal (TM) systems were 267 (IQR 223) and 201 (IQR 280) days, respectively. At one year, recanalization occurred in 11 veins treated with the VariClose (R) system and 5 veins treated with the VenaSeal (TM) system. The occlusion rates estimated by the Kaplan-Meier method at 30, 90, 180, and 360 days were 100%, 96%, 83%, and 42% for veins treated with the VariClose (R) system and 100%, 98%, 96%, and 91% for veins treated with the VenaSeal (TM) system (p <0.01). Conclusions: The VenaSeal (TM) system had significantly better occlusion rates than the VariClose (R) system.

Pancreaticoduodenal artery aneurysms are rare visceral artery aneurysms that may be associated with stenosis of the coeliac trunk. We present a case of a 48-year-old woman with a symptomatic aneurysm of the inferior pancreaticoduodenal artery caused by occlusion of the coeliac trunk due to median arcuate ligament syndrome. The patient was treated with an aorto-hepatic bypass and excision of the aneurysm. We discuss the case and the complexities and controversies in the treatment of this disease.

Background: A new silver-based dressing has been designed to reduce surgical sited infections. Patients and Methods: A prospective multicenter observational study was conducted from January 2020 to October 2021. Patients with and without silver-based dressing after surgical incision were observed and their data analyzed. The study aimed to assess the incidence of incisional surgical site infection and primary healing after general surgery procedures. Results: Overall, 218 patients with silver-based (n = 109) and conventional silver-free dressing (n = 109) were analyzed. Surgical site infection (SSI) and primary incision healing were reported in 10 (9.2%) versus 21 (19.3%) (p = 0.037) and in 95 (87.2%) versus 86 (78.9%) (p = 0.107) patients treated with and without silver-based dressing, respectively. Conclusions: Silver-based dressing demonstrated a lower incidence of incisional SSI and improved primary healing in comparison with patients in whom conventional non-silver-based dressing has been used.

BACKGROUND:One of the three commercially available cyanoacrylate venous glues used for the treatment of saphenous vein insufficiency is the VariClose® vein sealing system. Previous studies have documented a high rate of occlusion and minimal postoperative complications. The aim of this study was to compare occlusion rates and clinical outcomes of endovenous laser treatment with the VariClose® vein sealing system in the treatment of truncal vein insufficiency.PATIENTS AND METHODS:Retrospective non-randomized single center study with prospectively collected data comparing endovenous laser treatment and VariClose® procedures between April 2018 and November 2019.RESULTS:VariClose® was used in 27 patients (30 veins) and endovenous laser treatment in 42 patients (51 veins). The occlusion rate at one, three, and six months were 96%, 85%, and 65% for VariClose® procedures and 100%, 100%, and 97% for endovenous laser treatment procedures (p = 0.01), respectively. Reduction of VCSS scores before treatment and at the last postoperative follow-up visit in the VariClose® group dropped by an average of 1.8 ± 1.6 and in the endovenous laser treatment by an average of 3.3 ± 2.9 (p = 0.01).CONCLUSION:VariClose® vein sealing system is inferior to endovenous laser treatment as a treatment option for varicose veins as it has a higher recanalization rate.

Objectives The treatment of concomitant abdominal aortic aneurysms and renal tumours is controversial. The aim of this study was to ascertain which of the following three strategies, one-stage open aneurysm repair and nephrectomy, two-stage open aneurysm repair and nephrectomy or two-stage endovascular aneurysm repair and nephrectomy, is the best approach. Methods systematic review and meta-analysis of articles published between January 1992 and April 2021 describing the treatment of concomitant abdominal aortic aneurysms and renal tumours. Results A total of 1168 records were identified. After the selection process, 12 studies with data on 89 patients were included. Sixty-two patients underwent one-stage open procedures, 18 patients underwent two-stage open procedures and nine underwent two-stage endovascular procedures. The overall postoperative mortality was 0.82% (95% CI, 0.00–4.61). The postoperative mortality for one-stage open procedures was 3.09% (95% CI, 0.00–10.11). No deaths occurred in the postoperative period open two-stage procedures or two-stage endovascular procedures. The weighted postoperative morbidity for all procedures was 23.86% (95% CI, 12.64–35.08) and for open one-stage procedures was 37.40% (95% CI, 14.33–60.47). Data concerning postoperative complications of two-stage open procedures were extractable from only one patient in whom no complications were reported. Two postoperative complications were reported after two-stage endovascular procedures from a total of six patients with extractable postoperative data. We were unable to perform meta-analysis on long-term outcomes as the data were reported non-uniformly. Conclusion There is currently no evidence to suggest that any procedure is associated with better outcomes. However, a one-stage open approach was the most commonly used option, favoured as it avoids delaying treatment of either of the conditions. Two-stage open procedures were preferred in cases where the surgical risk of a one-stage procedure was higher than the potential benefit. For such cases, two-stage endovascular repair is becoming more popular as a less invasive approach.

Objectives: The aim of this study was to assess occlusion rates of saphenous veins treated with the VariClose vein sealing system. Methods: A retrospective analysis including a total of 64 patients from four centres from the Czech Republic. Occlusion was defined as a non-compressible vein with absence of flow with exception to the first 3 cm from the saphenofemoral or saphenopopliteal junction on duplex ultrasound. Results: In 64 patients a total of 79 veins were treated. Technical success of the procedure was achieved in 74 (94%) of cases. The mean follow-up was 5.5 months. The closure rates calculated by the Kaplan-Meier method at 1, 3, 6 and 12 months were 94%, 85%, 69% and 36%, respectively, and there were no significant differences between centers. The average difference in VCSS score before and after the procedure was 1.8. Conclusions: The present study demonstrated surprisingly worse occlusion rates than the current literature.

IntroductionClassifications are important clinical tools that enable data arrangement, patient categorisation and comparative research. The care of patients with end-stage renal disease who have vascular access requires collaboration of several specialists. In such a field, where several different specialties overlap, strong evidence and well-grounded recommendations for good practice are essential. In this protocol, we aim to search the literature to identify classification systems regarding vascular access for haemodialysis. This protocol serves as a pragmatic tool for setting a systematic approach using scoping review methodology. It also aims to make the study transparent and avoid potential duplication.Methods and analysisWe will follow the Joanna Briggs Institute methodology for the conduct of scoping reviews during the course of the proposed review. Scopus, Web of Science, PubMed, Google Scholar and the ClinicalTrials.gov registry will be searched by two researchers. Titles and abstracts will be screened and articles featuring classifications regarding vascular access for haemodialysis will be eligible for full-text analysis. There will be no age, sex or race limitation for the study populations. The title and abstract (if abstract available) must be in English but there will be no language restrictions for full-text review. Databases will be searched from inception to the date of search. All patients indicated for creation or placement of vascular access will be eligible, as well as patients with already existing vascular access. Classifications regarding preprocedural assessment, vascular access insertion or creation, complications and their management will be included in the study. Classifications regarding peritoneal dialysis will not be eligible. A comprehensive summary of the available evidence will be presented.Ethics and disseminationThe protocol and the review are exempt from ethical approval as there is no direct patient involvement and the review will summarise data from already published literature. The final article will be submitted to a peer-reviewed scientific journal.

A large tumorous mass completely surrounding and compressing the coeliac trunk was identified on computed tomography in a young woman with a six-month history of progressive abdominal pain. The tumor was excised along with the coeliac trunk and the proximal parts of its branches. The hepatic artery was reconstructed with an aorto-hepatic autogenous bypass. Postoperatively the patient had neurogenic diarrhea, which subsided on medical treatment. Seven months after surgery the patient is in a good state of health and living a normal life.