Intraoperative transit time flow measurement predicts maturation of radiocephalic arteriovenous fistulas.

OBJECTIVE: The arteriovenous fistula (AVF) is the first choice for gaining vascular access for hemodialysis. However, 20% to 50% of AVFs fail within 4 months after creation. Although demographic risk factors have been described, there is little evidence on the intraoperative predictors of AVF maturation failure. The aim of this study was to assess the predictive value of intraoperative transit time flow measurements (TTFMs) on AVF maturation failure. METHODS: In this retrospective cohort study, intraoperative blood flow, measured using TTFM, was compared with AVF maturation after 6 weeks in 55 patients. Owing to its significantly higher prevalence and risk of nonmaturation, the radiocephalic AVF (RCAVF) was the main focus of this study. A recommended cutoff point for high vs low intraoperative blood flow was determined for RCAVFs, using a receiver operating characteristic curve. RESULTS: The average intraoperative blood flow in RCAVFs was 156 mL/min. Patients with an intraoperative blood flow equal or lower than the determined cutoff point of 160 mL/min, showed a 3.03 times increased risk of AVF maturation failure after 6 weeks, compared with patients with a higher intraoperative blood flow (P < .001). CONCLUSIONS: The intraoperative blood flow in RCAVFs measured by TTFM provides an adequate means of predicting AVF nonmaturation 6 weeks after surgery. For RCAVFs, a cutoff point for intraoperative blood flow of 160 mL/min is recommended for maximum sensitivity and specificity to predict AVF maturation failure after 6 weeks.

Creating hemodialysis autogenous access in children and adolescents.

OBJECTIVE: End-stage renal disease (ESRD) in childhood and adolescence is rare, with relatively few published reports of pediatric ESRD vascular access. This study analyzes a 10-year experience creating arteriovenous fistulas (AVFs) in children and adolescents. Our goal is to review our strategy for creating functional autogenous vascular access in younger patients and report our results. METHODS: We retrospectively reviewed data and outcomes for consecutive vascular access patients aged ≤19 years during a 10-year period. Each patient had preoperative vascular ultrasound mapping by the operating surgeon in addition to physical examination. A distal forearm radiocephalic AVF was the first access choice when feasible, and a proximal radial artery inflow AVF was the next option. Demographic data, inflow artery, venous outflow target, and required transposition vs direct AVFs were variables included in the analysis. Primary and cumulative patency were calculated by Kaplan-Meier analysis. RESULTS: Thirty-seven AVFs were created in 35 patients. No grafts were used. Ages were 6 to 19 years (mean, 15 years), and 20 were male. Causes of ESRD included glomerular disease (n = 18) and urinary obstruction or reflux (n = 7), among others. Three had previous AVFs, and 10 were obese. The proximal radial artery supplied AVF inflow in 25 patients and the brachial artery in only seven. Eleven individuals required a transposition and one a vein translocation to the contralateral arm. No patients developed hand ischemia, although two later required banding procedures for high flow. Eleven patients had successful transplants. A single patient died, unrelated to the vascular access. Five AVFs failed. Of these, two had new successful AVFs created, two regained renal function, one was transplanted, and one declined other procedures. Primary and cumulative patency rates were 75% and 85% at 12 months, 70% and 85% at 24 months, and 51% and 85% at 36 months, respectively. Median follow-up was 16 months. CONCLUSIONS: Creating an AVF for hemodialysis is a successful vascular access strategy for pediatric and adolescent patients. Proximal radial artery AVFs provided safe and functional access when a distal AVF was not feasible. Cumulative AVF patency was 85% at 36 months.

Management of Arteriovenous Fistula After Successful Kidney Transplantation in Long-Term Follow-Up.

Arteriovenous fistula (AVF) is the best method of vascular access for hemodialysis. This approach can lead to several complications, such as hyperkinetic heart failure due to a hyperfunctional AVF or dilatation of the feeding artery. These are late complications, especially in patients after a successful kidney transplantation. An observational study was performed focusing on patients more than 12 months after kidney transplantation. The AVF was evaluated by ultrasound and, if the outflow exceeded 1.5 L/min, an echocardiogram was performed. Surgical management was indicated if the cardiac index was higher than 3.9 L/min/m2 or upon finding a brachial artery aneurysm. A total of 208 post- kidney transplantation patients were examined over a 3-year period, of which 46 subjects (22.11%) had hyperfunctional AVF and 34 cases (16.34%) of feeding artery dilatation were determined. In total, 40 AVF flow reduction and 6 AVF ligation procedures were performed. The median AVF flow before and after the reduction was 2955 mL/min and 1060 mL/min, respectively. Primary patency after flow reduction was 88.3% at 12 months. Late AVF complications in patients following kidney transplantation are quite common. It is necessary to create a screening program to monitor AVFs in these patients.

Establishing an autogenous vascular access program in a Guatemalan comprehensive pediatric nephrology center.

BACKGROUND: The Guatemalan Foundation for Children with Kidney Diseases collaborated with Bridge of Life, a not-for-profit charitable organization, to establish a vascular access program. We reviewed our experience with graded surgical responsibility and structured didactic training, creating arteriovenous fistulas (AVF) for Guatemalan children. METHODS: Pediatric vascular access missions were completed from 2015 to 2023 and analyzed retrospectively. Follow-up was completed by the Guatemalan pediatric surgeons, nephrologists, and nursing staff. AVF patency and patient survival were evaluated by Kaplan-Meier life-table analysis with univariate and multivariable association between patient demographic variables by Cox proportional hazards models. RESULTS: Among a total of 153 vascular access operations, there were 139 new patient procedures, forming the study group for this review. The mean age was 13.6 years, 42.6% were female, and the mean BMI was 17.3. Radial or ulnar artery-based direct AVFs were established in 100 patients (71.9%) and ten of the 25 transposition procedures. Brachial artery inflow was required in 29 direct AVFs (20.9%). Two patients underwent femoral vein transpositions. Access-related distal ischemia was not encountered. Seven of the AVF patients later required access banding for arm edema; all had previous dialysis catheters (mean = 9, range 4-12). Primary and cumulative patency rates were 84% and 86% at 12 months and 64% and 81% at 24 months, respectively. The median follow-up was 12 months. Overall patient survival was 84% and 67% at 12 and 24 months, respectively. There were no deaths related to AVF access. CONCLUSIONS: Safe and functional AVFs were established in a teaching environment within a Guatemalan comprehensive pediatric nephrology center.

Is central venous catheter in haemodialysis still the main factor of mortality after hospitalization?

BACKGROUND: Haemodialysis is the most frequently prescribed Renal Replacement Therapy modality worldwide. However, patients undergoing this therapy have an unpredictable evolution related to vascular access. OBJECTIVE: To determine the factors associated with the mortality and hospitalization rate in haemodialysis patients at a third-level care Centre in the Dominican Republic. METHODS: This was an observational and prospective study involving a cohort of 192 haemodialysis patients. The patient selection was non-probabilistic for convenience, and a direct source questionnaire was applied. RESULTS: Of the 192 patients in the cohort, 103 (53.6%) were hospitalized and evaluated. The most frequent cause of hospitalization was catheter-related bloodstream infections (53.4%). Almost one-third (28.2%) of the hospitalized patients died, mostly due to infections (12.6%). Of those who died 29 patients (90%) had a Central venous catheter (CVC) with a non-tunnelled catheter (NTCVC) (65.5%); having an NTC CVC makes a patient 85.5 times more likely to be hospitalized than patients with arteriovenous fistulas. CONCLUSION: Vascular access plays a predominant role in the hospitalization and mortality rates in haemodialysis. Patients with an arteriovenous fistula obtained significantly better outcomes than those with central venous catheters.

To evaluate the complication and patency rate of superficial femoral vein transposition in tertiary care center.

INTRODUCTION: When all access options in the upper extremity have been exhausted, an autologous access can be created in lower extremity. The purpose of this study is to report our experience with superficial femoral vein transposition (SFVT) results in terms of postoperative complication and patency rate. MATERIALS AND METHODS: In the time period from January 1, 2019 to April 30, 2021, thirty-five cases of SFVT performed at our large tertiary care center Sindh Institute of Urology and Transplantation (SIUT). All patients had exhausted upper arm veins or had central vein obstructions. Medical records of all patients were traced, patients were interviewed using a standard proforma and evaluated the current AVF function in the OPD clinic or by telephone calls. Data including demographics and postoperative complications were collected. RESULTS: Thirty-nine cases of SFVT performed at our institute. Three were immediately lost to follow up so they were excluded from the study. Mean patient age was 30 ± 13.4 years. Most of our patients were females (57%) and 15 males (43%) with an average age of 29.05 years. The most common underlying renal diseasewas unknown in 16 (45%).Thirty-five patients included in the analysis; out of which primary failure observed in 4 patients, three patients were expired before fistula maturation and 3 were expired before 6 months. The remaining 25 fistulas patency rates were estimated. No any patient died due to fistulas related complication; patients died due to their primary disease. CONCLUSION: Our study shows that with appropriate patient selection, SFVT have low infection rates and patency that is comparable with other access types.

Factors associated with dysfunction of autogenous arteriovenous fistula in patients with secondary hyperparathyroidism after parathyroidectomy.

BACKGROUND: Secondary hyperparathyroidism (SHPT) is a prevalent chronic complication in patients undergoing hemodialysis. Parathyroidectomy (PTX) is crucial for reducing mortality and improving the prognosis in the treatment of refractory hyperparathyroidism. However, it is often associated with a number of postoperative complications such as postoperative hypotension, hyperkalemia, and hungry bone syndrome. A previous study demonstrated that low blood pressure influences the patency of autogenous arteriovenous fistulas (AVF). Few studies have examined AVF dysfunction following PTX. This study aimed to identify and describe the risk variables associated with AVF dysfunction after PTX. METHODS: Cases of AVF dysfunction after PTX between 2015 and 2021 were studied. Four controls were identified for each patient and were matched for sex and age. Biochemical parameters and blood pressure of the patients before and after PTX were recorded. Risk factors for AVF dysfunction after PTX were identified using conditional logistic regression analysis. RESULTS: Sixteen patients and 64 controls were included in this study. Baseline demographic and laboratory data were compared. Patients in the AVF dysfunction group had lower levels of postoperative calcium than the controls. After surgery, calcium levels decreased more in patients with AVF dysfunction than in the control group. The decrease in systolic blood pressure (ΔSBP) after PTX was greater in the AVF dysfunction group than that in the control group. For each 1 mmHg increment in ΔSBP, the risk of AVF dysfunction after surgery increased by 11.6% (OR = 1.116, 95% CI, 1.005-1.239, p = .040). The likelihood of developing AVF dysfunction after surgery was twelvefold higher in diabetic patients than in non-diabetic patients (OR = 12.506, 95% CI, 1.113-140.492, p = .041). Among patients with ΔSBP > 5.8 mmHg after PTX, the AVF failure rate was significantly greater in patients with diabetes than in those without diabetes. Patients with a history of AVF failure had a nine-fold higher risk of developing AVF dysfunction (OR = 9.143, 95% CI, 1.151-72.627, p = .036). Serum albumin, hemoglobin, ΔiPTH, and age were not independent predictors of AVF dysfunction. The cutoff value for SBP was 5.8 mmHg, as determined by the Youden index of the receiver operating characteristic curve. CONCLUSION: Decreased systolic blood pressure (ΔSBP) after PTX, diabetes, and AVF failure history were risk factors for AVF dysfunction following PTX in patients with SHPT. Diabetes patients with ΔSBP > 5.8 mmHg were more prone to AVF dysfunction after PTX.

Outcomes of AV fistula formation for dialysis patients using interrupted sutures one-year single center study.

Objectives: To document the Outcomes of AV fistula formation for dialysis patients using interrupted sutures. Methods: In this Cross-sectional study conducted at PNS Shifa Karachi, from June 2022 to June 2023, patients above 18 years of age, male or female, with ESRD/CKD were included. After clinical screening and ultrasound doppler, the distal most part of wrist was considered as a site for radio cephalic AVF. Operation was performed under surgical loupe with 4.5x magnification. Standard incision of about 4-5 cm oblique proximal to the wrist crease was given at the volar surface on the radial side of Distal forearm, extending till the lateral side up to the snuffbox. Subcutaneous tissue was incised and dissection was done to identify the cephalic vein and radial artery. Distal most end of the cephalic vein was ligated using vicryl 4-0 suture and cephalic vein dissected free from the underling tissue to mobilize it up to the radial artery. Results: During the study N=35 patients who required AVF creation visited the department. The mean age of the study participants was 59.34±15.48. If thrill at the site of AVF and backflow at cut end of cephalic vein were present the surgeons were satisfied, higher satisfaction among the surgeon was achieved in the AVF created at brachiocephalic artery while the diameter of vessels didn't contribute in surgeon satisfaction. Conclusion: Presence of thrill at the site of AVF and backflow at cut end of cephalic vein have strong association with good prognosis of AVF.

Patient and Clinician Perspectives on Shared Decision Making in Vascular Access Selection: A Qualitative Study.

RATIONALE & OBJECTIVE: Collaborative approaches to vascular access selection are being increasingly encouraged to elicit patients' preferences and priorities where no unequivocally superior choice exists. We explored how patients, their caregivers, and clinicians integrate principles of shared decision making when engaging in vascular access discussions. STUDY DESIGN: Qualitative description. SETTING & PARTICIPANTS: Semistructured interviews with a purposive sample of patients, their caregivers, and clinicians from outpatient hemodialysis programs in Alberta, Canada. ANALYTICAL APPROACH: We used a thematic analysis approach to inductively code transcripts and generate themes to capture key concepts related to vascular access shared decision making across participant roles. RESULTS: 42 individuals (19 patients, 2 caregivers, 21 clinicians) participated in this study. Participants identified how access-related decisions follow a series of major decisions about kidney replacement therapy and care goals that influence vascular access preferences and choice. Vascular access shared decision making was strengthened through integration of vascular access selection with dialysis-related decisions and timely, tailored, and balanced exchange of information between patients and their care team. Participants described how opportunities to revisit the vascular access decision before and after dialysis initiation helped prepare patients for their access and encouraged ongoing alignment between patients' care priorities and treatment plans. Where shared decision making was undermined, hemodialysis via a catheter ensued as the most readily available vascular access option. LIMITATIONS: Our study was limited to patients and clinicians from hemodialysis care settings and included few caregiver participants. CONCLUSIONS: Findings suggest that earlier, or upstream, decisions about kidney replacement therapies influence how and when vascular access decisions are made. Repeated vascular access discussions that are integrated with other higher-level decisions are needed to promote vascular access shared decision making and preparedness.

Early clinical experience and comparison between percutaneous and surgical arteriovenous fistula.

BACKGROUND: Percutaneous arteriovenous fistula (pAVF) has been recently developed as an alternative to surgical AVF (sAVF). We report our experience with pAVF in comparison with a contemporaneous sAVF group. METHODS: Charts of all 51 patients with pAVF performed at our institution were analyzed retrospectively, in addition to 51 randomly selected contemporaneous patients with sAVF (2018-2022) with available follow-up. Outcomes of interest were (i) procedural success rate, (ii) number of maturation procedures required, (iii) fistula maturation rates, and (iv) rates of tunneled dialysis catheter (TDC) removal. For patients on hemodialysis (HD), sAVF and pAVF were considered mature when the AVF was used for HD. For patients not on HD, pAVF were considered mature if flow rates of ≥500 mL/min were documented in superficial venous outflow; for sAVF, documentation of maturity based on clinical criteria was required. RESULTS: Compared patients with sAVF, patients with pAVF were more likely to be male (78% vs 57%; P = .033) and less likely to have congestive heart failure (10% vs 43%; P < .001) and coronary artery disease (18% vs 43%; P = .009). Procedural success was achieved in 50 patients with pAVF (98%). Fistula angioplasties (60% vs 29%; P = .002) and ligation (24% vs 2%; P = .001) or embolization (22% vs 2%; P = .002) of competing outflow veins were more frequently performed on patients with pAVF. The surgical cohort had more planned transpositions (39% vs 6%; P < .001). When all maturation interventions were combined, pAVF required more maturation procedures, but this was not statistically significant (76% vs 53%; P = .692). When planned second-stage transpositions were excluded, pAVF had a statistically significant higher rate of maturation procedures (74% vs 24%; P < .001). Overall, 36 pAVF (72%) and 29 sAVF (57%) developed mature fistulas. This difference, however, was not statistically significant (P = .112). At the time of AVF creation, 26 patients with pAVF and 40 patients with sAVF were on HD, all through use of a TDC. Catheter removal was recorded in 15 patients with pAVF (58%) and 18 patients with sAVF (45%) (P = .314). The mean time until TDC removal in pAVF group was 146 ± 74 days, compared with 175 ± 99 in the sAVF group (P = .341). CONCLUSIONS: Compared with sAVF, rates of maturation after pAVF seem to be similar, but this result may be related to the higher intensity of maturation procedures and patient selection. An analysis of appropriately matched patients will assist in elucidating the possible role of pAVF vis-a-vis sAVF.

A systematic review aggregated data and individual participant data meta-analysis of percutaneous endovascular arteriovenous fistula.

OBJECTIVE: To assess the short-term and mid-term safety and efficacy of percutaneous endovascular arteriovenous fistula (pAVF) creation. METHODS: A systematic search was implemented corresponding to the PRISMA 2020 and the PRISMA for individual participant data (IPD) systematic reviews 2015. Aggregated data from the included studies were obtained and meta-analyzed regarding both the overall pAVF efficacy and the comparison of pAVF with surgical AVF (sAVF). We performed a two-stage IPD meta-analysis for studies comparing pAVF and sAVF regarding primary and secondary patency. Primary end points included primary patency, secondary patency, and functional cannulation. RESULTS: Eighteen studies with 1863 patients were included. The overall pAVF, primary patency, secondary patency, functional cannulation and abandonment rates were 54.01% (95% confidence interval [CI], 40.69-66.79), 87.27% (95% CI, 81.53-91.42), 79.94% (95% CI, 65.94-89.13), and 15.58% (95% CI, 7.77-28.79), respectively. The overall pAVF, technical success, maturation, reintervention per person-years and mean time to maturation rates were 97.08% (95% CI, 95.66-98.04), 82.13% (95% CI, 71.64-89.32), 0.80 (95% CI, 0.34-1.47), and 58 days (95% CI, 36.64-92.82), respectively. Secondary patency and pAVF abandonment rates where the only end points were WavelinQ and Ellipsys displayed statistically significant differences of 81.36% (95% CI, 76.15-85.65) versus 92.12% (95% CI, 87.94-94.93) and 32.54% (95% CI, 22.23-44.87) versus 11.13% (95% CI, 4.82-23.65). An IPD meta-analysis of hazard ratios for primary and secondary patency between pAVF and sAVF were 1.27 (95% CI, 0.61-2.67) and 1.25 (95% CI, 0.87-1.80), favoring sAVF. Statistically significant difference between pAVF and sAVF were solely depicted for steal syndrome relative risk of 5.91 (95% CI, 1.12-31.12) and wound infections relative risk of 4.19 (95% CI, 1.04-16.88). Plotting of pAVF smoothed hazard estimate displayed an upsurge in the probability of primary patency failure at 1 month after the intervention. CONCLUSIONS: Although we failed to identify statistically significant differences between pAVF and sAVF regarding any of the primary end points, pAVF displayed a decreased risk for steal syndrome and wound infection. Although both the Ellipsys and WavelinQ devices displayed satisfactory secondary patency rates, Ellipsys demonstrated a statistically significant improved rate compared with WavelinQ. Additionally, and despite the borderline statistically insignificant inferior reintervention rate displayed by WavelinQ, one in three WavelinQ pAVFs resulted in abandonment. The introduction of pAVF as a treatment modality calls for standardized definition adjustment and improvement.

Systematic review and meta-analysis of preoperative interventions to support the maturation of arteriovenous fistulae in patients with advanced kidney disease.

BACKGROUND: There is great potential to improve outcomes of arteriovenous fistulas (AVFs) by focusing more on the preoperative period of AVF creation. We aim to systematically review the evidence on safety and efficacy of various preoperative interventions that have been tried to improve AVF maturation and success rate. METHODS: We searched five databases: PubMed, Embase, CINAHL, Cochrane Library and King's Fund Library. Experimental studies that investigated the effect of various preoperative interventions to improve AVF outcomes among advanced chronic kidney disease (CKD) patients were searched. The effect size for primary outcome was calculated as the weighted mean difference in the final vessel calibre, rate of AVF maturation or primary failure between the intervention and control arm. We also assessed adverse effects and dropout rates. This review was preregistered in the International Prospective Register of Systematic Reviews (CRD42020193257). RESULTS: Eight eligible studies were identified involving three types of intervention: hand exercise (n = 6), cholecalciferol supplementation (n = 1) and pneumatic compression of the arm using a Fist Assist device (n = 1). The overall effect size of hand exercise on distal cephalic vein calibre was 0.24 mm [95% confidence interval (CI) 0.03-0.45] on meta-analysis of hand exercise studies. On restricting analysis to two randomized controlled trials (RCTs) that had independent control groups, the effect size was higher, at 0.29 mm (95% CI 0.11-0.47). Hand exercise was a well-tolerated intervention, especially when confined to the first 4 weeks. DISCUSSION: Hand exercise is the predominant intervention tried in the preoperative period of AVF creation, although there is methodological heterogeneity. Intermittent pneumatic compression using a Fist Assist device is a novel intervention that has shown some promise. Well-designed prospective RCTs are needed on preoperative interventions among advanced CKD patients, aimed at improving AVF outcomes.

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

BACKGROUND: Arteriovenous fistula (AVF) is the gold standard vascular access for effective hemodialysis. There is a growing interest in AVF creations performed by nephrologists to help reduce vascular surgeons' workload and enhance the timely treatment of patients with end-stage renal disease (ESRD). However, little is known about the feasibility and effectiveness of this approach in the low-resource settings. We examined the AVF surgical success and failure rates and associated predictors as well as early complications of AVF creations by a trained nephrologist with supports from vascular surgeons in Vietnam. METHODS: A prospective cohort study was conducted on all adult ESRD patients at the Hemodialysis Department of Thong Nhat Hospital between April 2018 and October 2020. Information on demographic characteristics, comorbidities, and AVF creations was collected using a standardized questionnaire. All patients were followed up until 18 weeks post-surgery. RESULTS: Among 100 patients with a mean age of 61.22 ± 17.11 years old, male accounted for 54%. Common causes of ESRD included hypertension (57%) and diabetes (32%). Just more than half (52%) of them reported having an AVF creation prior to ESRD. The successful first-time AVF creation rate was 98% (13/99, 95%CI: 8.74-21.18%). The primary and secondary AVF failure rates were 13.13% (13/99, 95%CI: 8.74-21.18%) and 16.87% (14/83, 95%CI: 10.32-26.25%), respectively. Early complications included bleeding (1%) and early thrombosis of the anastomosis (2%). There was a statistically significant association between age and primary AVF failure (P = 0.005) and between operation time and secondary AVF failure (P = 0.038). CONCLUSIONS: AVF creations performed by well-trained and skilled interventional nephrologists with supports from vascular surgeons can result in favorable short- and long-term outcomes. It is important to follow up older patients and those with a long operation time to detect AVF failures. A standardized AVF creation training program and practice for nephrologists is needed to increase successful rates.

Chest pain with ST-elevation in leads AVR, III, AVF, V1, V3R, V4R and V5R.

We mistakenly diagnosed a patient with pulmonary embolism as ST-elevation acute myocardial infarction. The case complained of chest pain with ST-elevation in leads AVR, III, AVF, V1, V3R, V4R and V5R. In addition, we also found ST- elevation AVR, III>ST- elevation AVF, QIII>QAVF and QV1. Multi-site pulmonary embolism can lead to type 2 myocardial infarction or special type of myocardial infarction with non-obstructive coronary arteries through multiple pathological mechanisms.

Increased expression of the P2Y12 receptor is involved in the failure of autogenous arteriovenous fistula caused by stenosis.

OBJECTIVE: This study investigated the role of the P2Y12 receptor in autogenous arteriovenous fistula (AVF) failure resulting from stenosis. METHODS: Stenotic venous tissues and blood samples were obtained from patients with end-stage renal disease (ESRD) together with AVF stenosis, while venous tissues and blood samples were collected from patients with ESRD undergoing initial AVF surgery as controls. Immunohistochemistry and/or immunofluorescence techniques were utilized to assess the expression of P2Y12, transforming growth factor-ß1 (TGF-ß1), monocyte chemotactic protein 1 (MCP-1), and CD68 in the venous tissues. The expression levels of P2Y12, TGFß1, and MCP-1 were quantified using quantitative reverse transcription-polymerase chain reaction and western blot analyses. Double and triple immunofluorescence staining was performed to precisely localize the cellular localization of P2Y12 expression. RESULTS: Expression levels of P2Y12, TGFß1, MCP-1, and CD68 were significantly higher in stenotic AVF venous tissues than in the control group tissues. Double and triple immunofluorescence staining of stenotic AVF venous tissues indicated that P2Y12 was predominantly expressed in α-SMA-positive vascular smooth muscle cells (VSMCs) and, to a lesser extent, in CD68-positive macrophages, with limited expression in CD31-positive endothelial cells. Moreover, a subset of macrophage-like VSMCs expressing P2Y12 were observed in both stenotic AVF venous tissues and control venous tissues. Additionally, a higher number of P2Y12+/TGF-ß1+ double-positive cells were identified in stenotic AVF venous tissues than in the control group tissues. CONCLUSION: Increased expression of P2Y12 in stenotic AVF venous tissues of patients with ESRD suggests its potential involvement in the pathogenesis of venous stenosis within AVFs.

Endovascular salvage of thrombosed haemodialysis vascular access.

Background: Haemodialysis access thrombosis is associated with significant morbidity and access abandonment rates, for which endovascular salvage is a well described treatment option. This study aimed to evaluate the outcomes of endovascular salvage procedures of thrombosed vascular access circuits and identify factors influencing outcomes. Patients and methods: Retrospective review of 328 consecutive procedures performed over 10 years at our institution between January 2010 and December 2019. Patient demographics, access circuit characteristics, procedure details and outcome data were collected. Kaplan-Meier survival curves were used to estimate patency rates and Cox multivariate regression analysis to identify factors affecting outcomes. Results: Technical and clinical success rates were 87.8% and 75.9% respectively. The primary, primary assisted and secondary patency rates at 6 months were 42.2%, 46.7% and 59.1%; and at 12 months were 23.4%, 28.3% and 41.8% respectively. Median access circuit survival was 9.2 months. Major complication rate was 5.2% including 3 procedure-related deaths. Native AVF, lower time from thrombosis to intervention and pharmacomechanical thrombectomy using AngioJetTM predicted positive outcomes. Previous thrombectomy within 3 months and residual thrombus at completion were associated with poorer outcomes. Age and hypertension predicted higher complication rates. Conclusions: This is one of the largest single center series of endovascular salvage of thrombosed haemodialysis access and demonstrates that endovascular treatment is effective and provides durable access circuit survival. Careful patient screening is essential to optimize outcomes.

Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix.

Vascular access is the lifeline for patients receiving haemodialysis as kidney replacement therapy. As a surgically created arteriovenous fistula (AVF) provides a high-flow conduit suitable for cannulation, it remains the vascular access of choice. In order to use an AVF successfully, the luminal diameter and the vessel wall of the venous outflow tract have to increase. This process is referred to as AVF maturation. AVF non-maturation is an important limitation of AVFs that contributes to their poor primary patency rates. To date, there is no clear overview of the overall role of the extracellular matrix (ECM) in AVF maturation. The ECM is essential for vascular functioning, as it provides structural and mechanical strength and communicates with vascular cells to regulate their differentiation and proliferation. Thus, the ECM is involved in multiple processes that regulate AVF maturation, and it is essential to study its anatomy and vascular response to AVF surgery to define therapeutic targets to improve AVF maturation. In this review, we discuss the composition of both the arterial and venous ECM and its incorporation in the three vessel layers: the tunica intima, media, and adventitia. Furthermore, we examine the effect of chronic kidney failure on the vasculature, the timing of ECM remodelling post-AVF surgery, and current ECM interventions to improve AVF maturation. Lastly, the suitability of ECM interventions as a therapeutic target for AVF maturation will be discussed.

The PPAR-γ Agonist Pioglitazone Modulates Proliferation and Migration in HUVEC, HAOSMC and Human Arteriovenous Fistula-Derived Cells.

The failure of arteriovenous fistulas (AVFs) following intimal hyperplasia (IH) increases morbidity and mortality rates in patients undergoing hemodialysis for chronic kidney disease. The peroxisome-proliferator associated receptor (PPAR-γ) may be a therapeutic target in IH regulation. In the present study, we investigated PPAR-γ expression and tested the effect of pioglitazone, a PPAR-γ agonist, in different cell types involved in IH. As cell models, we used Human Endothelial Umbilical Vein Cells (HUVEC), Human Aortic Smooth Muscle Cells (HAOSMC), and AVF cells (AVFCs) isolated from (i) normal veins collected at the first AVF establishment (T0), and (ii) failed AVF with IH (T1). PPAR-γ was downregulated in AVF T1 tissues and cells, in comparison to T0 group. HUVEC, HAOSMC, and AVFC (T0 and T1) proliferation and migration were analyzed after pioglitazone administration, alone or in combination with the PPAR-γ inhibitor, GW9662. Pioglitazone negatively regulated HUVEC and HAOSMC proliferation and migration. The effect was antagonized by GW9662. These data were confirmed in AVFCs T1, where pioglitazone induced PPAR-γ expression and downregulated the invasive genes SLUG, MMP-9, and VIMENTIN. In summary, PPAR-γ modulation may represent a promising strategy to reduce the AVF failure risk by modulating cell proliferation and migration.

[Procedural simulation for nursing education]. / La simulation procédurale pour la formation des infirmiers.

Simulation is an educational tool that allows, in initial and continuing education, the acquisition of gestures and procedures. The management of the vascular approach concerning the arteriovenous fistula is not yet standardized. Thus, the standardization of the fistula puncture technique, approached through simulation, could be part of an approach to optimizing practices and continuous improvement of care.

Inhibition of ß-catenin signaling attenuates arteriovenous fistula thickening in mice by suppressing myofibroblasts.

BACKGROUND: Arteriovenous fistula (AVF) is the most important vascular access for hemodialysis; however, preventive treatment to maintain the patency of AVFs has not been developed. In endothelium, ß-catenin functions in both the intercellular adherens complex and signaling pathways that induce the transition of endothelial cells to myofibroblasts in response to mechanical stimuli. We hypothesize that mechanical disturbances in the AVF activate ß-catenin signaling leading to the transition of endothelial cells to myofibroblasts, which cause AVF thickening. The present study aimed to test this hypothesis. METHODS: Chronic kidney disease in mice was induced by a 0.2% adenine diet. AVFs were created by aortocaval puncture. Human umbilical vein endothelial cells (HUVECs) were used in the cell experiments. A pressure-culture system was used to simulate mechanical disturbances of the AVF. RESULTS: Co-expression of CD31 and smooth muscle alpha-actin (αSMA), loss of cell-cell adhesions, and the expression of the myofibroblast marker, integrin subunit ß6 (ITGB6), indicated transition to myofibroblasts in mouse AVF. Nuclear translocation of ß-catenin, decreased axin2, and increased c-myc expression were also observed in the AVF, indicating activated ß-catenin signaling. To confirm that ß-catenin signaling contributes to AVF lesions, ß-catenin signaling was inhibited with pyrvinium pamoate; ß-catenin inhibition significantly attenuated AVF thickening and decreased myofibroblasts. In HUVECs, barometric pressure-induced nuclear localization of ß-catenin and increased expression of the myofibroblast markers, αSMA and ITGB6. These changes were attenuated via pretreatment with ß-catenin inhibition. CONCLUSIONS: The results of this study indicate that mechanical disturbance in AVF activates ß-catenin signaling to induce the transition of endothelial cells to myofibroblasts. This signaling cascade can be targeted to maintain AVF patency.