Hemodialysis Arteriovenous Fistula Research Articles

Retained foreign body in radial artery: Endovascular retrieval and salvage of a hemodialysis arteriovenous fistula.

A foreign body was inadvertently retained in the patient's radial artery during a previous endovascular procedure, leading to early recurrent thrombosis of his hemodialysis arteriovenous fistula. Through the strategic use of ultrasound, a through-and-through wire, as well as sequential balloon inflation to "push" the foreign body, it was successfully retrieved endovascularly, leading to effective salvage of the patient's hemodialysis access.

Saphenous vein versus synthetic graft in arteriovenous fistula for hemodialysis in patient with inaccessible veins.

An autologous arteriovenous fistula (AVF) provides an optimal and secure way for managing the condition. An optimal blood supply to hemodialysis is linked to decreased incidence of complications and mortality, as well as reduced expenses. The objective of this research was to evaluate the outcome of people with suboptimal superficial venous system quality or who had exhausted all available arteriovenous fistula options, who received either autologous saphenous vein graft or polytetrafluoroethylene (PTFE) interposition graft as an access for effective hemodialysis. This prospective randomized controlled trail was carried out on fifty cases with chronic renal failure on hemodialysis and inaccessible superficial veins of both upper limbs for AVF. Cases were separated into two equal groups: Group A: cases performed saphenous vein reposition graft for hemodialysis access. Group B: cases who underwent PTFE interposition graft for prosthetic hemodialysis access. Time for maturation and time for graft maturation, operative time, hospital stay, and postoperative HB were significant increase in group A in contrast to group B (P<0.05). Blood loss was significant decrease in group A in contrast to group B (P<0.001). Patients underwent saphenous vein repositioning graft for hemodialysis access required prolonged operative time and hospital stay. Cases that underwent PTFE interposition graft for prosthetic hemodialysis access were less in time for maturation and time for graft maturation.

Factors Affecting Successful Creation of Arterio-venous Fistula for Hemodialysis

The preferred vascular access method for efficient hemodialysis is the arterio-venous fistula (AVF). There is a rising trend in AVF establishment conducted by nephrologists, aiming to alleviate the workload of vascular surgeons and expedite the prompt care of individuals afflicted with end-stage renal disease (ESRD). This descriptive observational study was conducted at the Department of Vascular Surgery, Ibrahim Cardiac Hospital and Research Institute during the period of June 2017 to July 2022. During the data collection period 1700 patients sought care in the Department for arterio-venous fistula creation, among them complete data of 1103 patients were included in this study. Majority of chronic kidney disease (CKD) patients were referred from the Department of Nephrology, BIRDEM for AVF creation in the mentioned timeline. Data were collected pre-designed data collection sheet and data were analyzed using Statistical Package for Social Sciences (SPSS) version- 25. This study shows that most of the patients (80.8%) were in ages 30 - 59 years and more than two-third (67.6%) of them were male; male-female ratio was 2:1. Diabetes mellitus (DM) was detected in nearly half of the patients (47.2%) and more than two-third (67.2%) of them were suffering from hypertension (HTN). Higher failure rate (73.3%) of AVF creation among patients of age group 30-59 years was significant. Failure rate for male patients was 57% and female patients was 43%. The AVF creation failure rates were 100% for patients with hypertension and for diabetes patients was 60.5%. Complications were found in 15.2% of patients. Post-operative edema and hematoma formation were more common (3.2% and 3.5%, respectively) in comparison to other complications. Among the complicated cases, 7 patients (4.2%) required intervention to correct stealing syndrome and AVF salvage was attempted in 43 cases (25.6%); medical management was pursued in 32(19.0%) cases. Majority (51.2%) of cases who were experiencing complications required AVF ligation. This research demonstrates that several significant clinical factors influence the successful establishment of an arterio-venous fistula (AVF) for hemodialysis factors include advanced age, being male, having diabetes (DM) and hypertension (HTN), having a history of Maintenance Hemodialysis (MHD) prior to AVF creation, choosing the wrist or arm as the AVF site, utilizing specific veins (cephalic and basilic) and specific arteries (radial and brachial). Bangladesh Med J. 2023 Sept; 52(3): 1-7

Ulnar-Basilic Arteriovenous Fistula for Hemodialysis: A 15-Year Overview.

Distal forearm arteriovenous fistulas (AVFs) for hemodialysis (HD) include radiocephalic fistulas (RCFs) and ulnar-basilic fistulas (UBFs). However, due to the unique anatomical peculiarities of the latter approach, UBFs are only established in a limited subset of patients undergoing vascular access procedures. This study aimed to present a retrospective case series detailing the creation of UBFs, emphasizing both the technical challenges and clinical outcomes associated with this approach. We conducted a retrospective review of UBFs created between 2008 and 2023. Data collected included patient demographics, comorbidities, patency, functionality, and outcomes. Adequate blood flow and personalized Kt/Vurea levels were prerequisites for defining UBF functionality for HD. Among 253 patients receiving HD, 82.2% had an AVF, with only 3.3% (n = 5) of the 150 distal AVFs functional for HD being UBFs. In this series, a total of 11 UBF fistulas were created, with nine patients experiencing an immediate thrill. Among those with UBF failure, three patients were aged > 85 years, and three had concurrent diabetes mellitus, peripheral vascular disease, and ischemic heart disease. The survival rate in the UBF group correlated with the duration of dialysis in the three patients for whom the UBF was the sole AVF, with one patient achieving a remarkably prolonged period of > 10 years. No incidences of ischemia, hand edema, or ulnar nerve lesions were noted. While the difficulties experienced in achieving functional UBFs for HD are highlighted in this long-term perspective, its safety and durability make it a viable option in managing an increasingly comorbid patient population.

What are the effects of surgical thrombectomy or the pulse spray technique compared with mechanical thrombectomy for treating people with thrombosed hemodialysis arteriovenous fistulas or grafts?

What are the effects of surgical thrombectomy or the pulse spray technique compared with mechanical thrombectomy for treating people with thrombosed hemodialysis arteriovenous fistulas or grafts?

Comparison of End-To-Side and Side-To-Side Anastomosis Techniques in Arteriovenous Fistula for Hemodialysis: A Systematic Review and Meta-Analysis.

Autogenous arteriovenous fistula (AVF) is the vascular access of choice for chronic kidney disease to patients requiring hemodialysis. However, there still needs to be more consensus on whether the best surgical approach is an end-to-side (ETS) or a side-to-side (STS) anastomosis. This study aims to compare venous maturation rates, midterm patency and postoperative steal syndrome rates between ETS and STS techniques for AVFs. Three databases were searched during November 2022: PubMed, Scopus, and ISI Web of Knowledge. Two independent reviewers examined both titles and abstracts. In all studies, eligibility was assessed, and data regarding the study's characteristics, methods, and considered outcomes were obtained. The odds ratio (OR) assessed maturation rates, 6- and 12-month patency, and steal syndrome. Meta-analysis was done using a fixed effects model if I2 values were under 30%, and a random-effects model from 30-60%. Thirteen studies were included, with a total of 1960 patients studied. Patients undergoing ETS anastomosis had higher maturation rates (OR 3.30 95% confidence interval [CI] 1.81, 6.00, I2=20%). No difference was found in patency at 6months (OR 1.05 95% CI 0.69, 1.59, I2=54%) and 12months (OR 0.75 95% CI 0.46, 1.23, I2=7%). Regarding steal syndrome, STS anastomosis presented a greater risk of developing this postoperative complication (OR 0.24 95% CI 0.11, 0.50, I2=0%). Thepresent review suggests that ETS anastomosis is associated with higher maturation rates and a lower risk of arterial steal syndrome. Randomized clinical trials are required to confirm our findings.

Liposuction for Superficialization of Deep Hemodialysis Vascular Access: A Novel Application.

More than 65% of patients with end-stage renal disease (ESRD) use arteriovenous fistulas (AVFs) for hemodialysis. The increasing incidence of comorbid ESRD and obesity (body mass index, >35 kg/m2) precludes patients from kidney transplantation, resulting in a need for long-term, durable AVF access. Compared with traditional superficialization techniques for overlying adiposity, liposuction is minimally invasive and well-tolerated, allowing for earlier fistula use with lower complications. We present the detailed surgical technique for superficialization of AVFs using liposuction. Fourteen patients with well-matured but difficult-access fistulas due to adiposity were selected. Preoperative ultrasound mapped depth of fistulas. Tumescent liposuction was completed in a cross-hatched manner. Intraoperative ultrasound confirmed cannula positioning and measured fistula depth. A palpable thrill remained throughout superficialization. Cannulation began 4 weeks postoperatively. Mean access depth preoperatively was 10.8 mm (8-15 mm), immediately postoperative was 7 mm (6-9 mm), and at 4 weeks was 5.3 mm (4-8 mm). The average usable access length was 12.7 cm (10-15 cm) after surgery. Thirteen fistulas were successfully accessed after liposuction superficialization. All patients were discharged home the same day. There were no postoperative infections or hemorrhage. Early experience with liposuction for superficialization of deep hemodialysis access is promising. This innovative solution has the possibility to improve outcomes and quality of life for patients living with ESRD and obesity. Our experience shows that this is a safe and effective technique to increase patient eligibility, enable successful and early cannulation, and decrease recovery time.

Prospective Analysis of Arteriovenous Fistula Performance in the Context of Competing Risks.

Many patients with newly created arteriovenous fistulas (AVF) may die before the AVF is needed for hemodialysis. However, formal competing risks frameworks are rarely used to report AVF patency, which may lead to biased estimates. We sought to identify the proportion of newly created AVF experiencing primary non-function and to describe long-term patency using a competing risk framework. We did a prospective observational study in 257 adults with newly created AVF in Alberta, Canada. The primary outcome was primary non-function. Secondary outcomes included loss of primary-patency, loss of assisted primary-patency, and loss of secondary functional-patency. Results were presented using icon-array plots to form the basis for future decision aids. Participants were 63.0% male with mean age 62.3 years and median follow-up of 18.5 months (range 0.02-180 months). Of 257 participants, 50 could not be assessed for function or primary non-function, usually due to death. Of the remaining 207, 102 (49.3%) had primary non-function, and function was ultimately established for 142 (68.6%). Thus, only 142 of the 257 participants (55.3%) ultimately used the AVF for hemodialysis. High rates of competing risks led to biased results from Kaplan-Meier analyses of lost patency. When accounting for competing risks, loss of primary-patency among AVF with established function was 36.6%, 65.5% and 66.2%, at 1y, 3y and 5y respectively. Only 55% of fistulas were ultimately used for hemodialysis when accounting for competing risks and primary non-function. These results and the icon-array plots may inform discussions surrounding vascular access options for patients.

Abstract 4137902: Layer-specific Gene Expression Associated with Intima Hyperplasia in Arterio-venous Fistula

Background: The mechanism of hemodialysis arteriovenous fistula (AVF) vein intima hyperplasia (IH) may be specific to its layers (intima, media, and adventitia) but is poorly understood. To address this gap, we studied layer-specific transcriptomics related to IH in veins of two-stage AVF creation. Methods: Vein samples were collected during the initial creation of brachial artery-basilic vein AVF (1st stage) and vein transposition surgery 6 weeks later (2nd stage) and were sectioned in OCT. Tissues from each layer were separately collected by laser microdissection. Following Takara’s SMARTer Stranded Total RNA-Seq Pico Input protocol, libraries were constructed and sequenced in NovaSeq. The sequencing reads were processed by fastp, aligned to genome GENCODE 45 by STAR and gene-level counts were estimated by RSEM. Intima was assessed by histology. Layer-specific differentially expressed genes in pre-access or AVF veins associated with IH in AVF veins were detected by edgeR and further identified the enriched pathways and predicted functions using Qiagen IPA. Results: 44 veins were collected from 22 patients. 13,522 protein-coding genes that had a raw count of at least 10 in more than 70% of samples were included in analysis. 10 AVF veins had severe IH. Among the layers of pre-access vein, intima had the largest number of genes significantly associated with severe AVF IH and most or all these genes were upregulated (35/4, 26/2, 5/0 for the number of up/downregulated genes in intima, media, and adventitia of pre-access vein, respectively); cellular movement and immune cell trafficking were more strongly activated in intima of pre-access vein with severe AVF IH. No genes in any layer of AVF vein were significantly associated with severe AVF IH. From 1 st to 2 nd stage, more genes significantly changed expression in intima with severe AVF IH than intima without severe AVF IH (197/150 vs 144/93 for up/downregulated genes), while media (20/4 vs 149/31) and adventitia (99/27 vs 196/70) were the opposite; TGFB1, angiotensinogen, and TNF were more strongly activated in intima, while cell survival and migration were diminished in media and adventitia with severe AVF IH, respectively. Conclusion: Intima of pre-access vein has more genes associated with severe AVF IH. The layer-specific gene expression changes during AVF development and predicted functions are associated with AVF IH. These data can be used to develop layer-specific therapies to reduce AVF IH.

102. Surgical Treatment of Brachial Artery Aneurysm Associated qith Arteriovenous Shunt for Hemodialysis: Case Report

Introduction: A brachial artery aneurysm is a rare complication of an arteriovenous fistula (AVF) created for hemodialysis access. This report details the case of a patient with a brachial artery aneurysm associated with an AVF for hemodialysis, who underwent successful surgical treatment. Case: A 64-year-old female with CKD undergoing regular hemodialysis presented with a painful lump in her right arm one-week AVF installation. Her medical history included a left nephrectomy in 2022, previous failed AV fistula placement, and central dialysis line (CDL) insertion. The patient had a medical history significant for CKD requiring routine HD twice a week. Local examination of the patient's right arm revealed a mobile, painful lump, diagnosed as a brachial artery aneurysm, limiting arm movement. A chest X-ray showed cardiomegaly, thoracic spondylosis, and proper CDL positioning. Laboratory results were normal. The patient underwent surgical repair of the aneurysm and was hospitalized for three days postoperatively. Post-surgery treatment included analgesics, antibiotics, anticoagulation therapy, and outpatient clopidogrel. Conclusions: A brachial artery aneurysm is a rare complication of an AVF, posing risks of peripheral embolism and hand ischemia, and therefore requires surgical correction.

Ultrasound evaluation of arteriovenous fistula for hemodialysis

The article presents a pictorial literature review on ultrasound evaluation of arteriovenous fistula for hemodialysis in patients with end-stage renal failure. Native arteriovenous fistula (AVF) is considered the “gold standard” of vascular access. Nowadays ultrasound is the first-line imaging modality of management of patients receiving hemodialysis treatment at all stages. The article highlights the role of ultrasound in preoperative assessment when planning the AVF creation, assessing the maturation of vascular access, as well as early detection of its dysfunction. The main complications of arteriovenous fistulas are presented, and examples of their diagnosis using the ultrasound are given.

The Potential of Sound Analysis to Reveal Hemodynamic Conditions of Arteriovenous Fistulae for Hemodialysis

PurposeArteriovenous fistula (AVF), the preferred vascular access for hemodialysis, is associated with high failure rate. The aim of this study was to investigate the potential of AVF sound auscultation in providing quantitative information on AVF hemodynamic conditions.MethodsThis single-center prospective study involved six patients with native radio-cephalic AVFs who underwent multiple follow-up visits. Doppler Ultrasound blood flow volume (BFV) assessment and electronic stethoscope-based sound recordings were performed during each visit, whereas MRIs were acquired 3 days, 3 weeks and 1 year after surgery. Computational fluid dynamic (CFD) simulations were performed on patient-specific MRI-derived geometrical models.ResultsHigher values of median peak amplitudes ratios (high-low peak ratio-HLPR) were found to be associated with complex blood flow and velocity streamlines recirculation at systolic peak, and corresponding extended regions of high oscillatory shear index (OSI). On the contrary, lower values of HLPR were associated with laminar flow pattern and low values of OSI. Significant differences were observed in HLPR between subgroups with extended or limited areas with OSI > 0.1 (0.67 vs 0.31, respectively). Significant relationships were found between AVF sound intensity and brachial BFV (slope = 0.103, p < 0.01) as well as between longitudinal changes in brachial BFV and HLPR (slope = − 0.001, p < 0.01).ConclusionOur results show that AVF sound can be exploited to extract fundamental information on AVF hemodynamic conditions, providing indication of the presence of complex hemodynamic and adequate BFV to perform hemodialysis. Sound analysis has therefore the potential to improve clinical AVF surveillance and to ameliorate outcome.

Efficacy of ultrasonography and color-Doppler for early prediction of hemodialysis arteriovenous fistula unassisted maturation.

Arteriovenous fistula (AVF) failure is a prevalent concern for patients with end-stage kidney disease on hemodialysis. Recognizing the efficacy of ultrasound Doppler in post-operative AVF evaluation, this study sought to discern the predictive capabilities of various ultrasonographic and color-Doppler metrics for early AVF outcomes. This single-center, prospective cohort study spanned 1 year and, post ethical clearance, included all patients who underwent native AVF creation surgery and were subsequently referred for standard post-operative ultrasound Doppler assessment. Parameters such as fistula size, cephalic vein area and diameter, and AVF flow velocity and rates were assessed on post-operative day 2, week 2, and week 6. These initial findings were juxtaposed with later outcomes to determine unassisted AVF results. Of the initial cohort of 40 patients, 75% encountered AVF failure, whereas 25% realized successful unassisted AVF maturation. A notable observation was the significant variance in AVF flow rates as early as post-operative day 2. A threshold of >246 ml/min was indicative of successful unassisted AVF maturation, leading to a sensitivity of 80% and a specificity of 70%. Although the cephalic vein diameter on post-operative day 2 lacked a robust association with AVF outcomes, a cut-off of >3.4 mm, when combined with flow rate testing, augmented the cumulative sensitivity to 92%. Ultrasound Doppler stands out as a valuable quantitative imaging modality, adept at prognosticating AVF outcomes from as early as post-operative day 2. In particular, a flow rate exceeding 246 ml/min and a cephalic vein diameter surpassing 3.4 mm are salient indicators for the early prediction of successful AVF outcomes.

Multicenter randomized controlled trial to assess the effectiveness of PASSEO-LUX DCB® drug coated balloon compared to plain balloon angioplasty of arteriovenous fistulae for hemodialysis: Two-years results.

To compare primary patency after angioplasty with drug-coated balloon (DCB)-Passeo-18Lux, BIOTRONIK versus uncoated balloon in dysfunctional peripheral vascular access (PVA) for hemodialysis. A total of 133 patients from four hospitals were randomized to receive DCB or plain old balloon angioplasty (POBA) after satisfactory treatment (residual stenosis <30%) with high pressure balloon (HPB). The primary endpoint was clinical patency of PVA 2 years after angioplasty. Secondary endpoints included the relationship between the location of stenosis and patency and also, other covariates. Mortality at 2 years was compared between both groups. Patency measured in days after angioplasty was higher in fistulae dilated with DCB than HPB. Kaplan-Meier survival curves showed the next percent of success (free time restenosis) after DCB versus POBA at 6 months-77.1% versus 58.2% (160.41-143.72 days until restenosis), 12 months-51.4% versus 44.3% (274.1-237.23), 18 months-38.6% versus 38% (350.74-305.18), and 24 months-37.1% versus 30.4% (419.04-369.1). At 6 months, this difference was statistically significant (p = 0.018), but not at 12 (p = 0.225), 18 (p = 0.471), or 24 months (p = 0.236). Mortality was similar in both groups. DCB angioplasty resulted in superior target lesion primary patency (TLPP)-free survival at 6 months of follow-up. No significant improvements in TLPP-free survival long term were observed. Mortality observed at 1 and 2 years was similar in DCB and POBA: there was no significant difference, and a safety study demonstrated no difference between the two groups (complications and mortality): DCB is safe to use in stenosis treatment in patients who are PVA carriers. Level Ia, therapeutic study, RCT. EBM ratings will be based on a scale of 1-5.

Effects of far infrared therapy in hemodialysis arterio-venous fistula maturation: A meta-analysis.

Hemodialysis patients rely on stable vascular access to perform effective hemodialysis and reach good dialysis quality. However, an obstructed or under-matured arteriovenous fistula (AVF) may increase infection rate and mortality in hemodialysis patients. Far infrared (FIR) therapy might help to promote AVF maturation and reduce obstruction rate. Therefore, this meta-analysis was conducted to evaluate the effect of FIR therapy on AVF obstruction rate and maturation. PubMed, Embase, the Cochrane Library, and other databases which provide publications in randomized controlled trials (RCTs) of FIR to improve AVF in patients with CKD (Chronic Kidney Disease) or HD (hemodialysis) were used to collect articles which published before February 2023. Two authors selected relevant articles independently based on pre-defined inclusion and exclusion criteria, and assessed the quality of the articles by using the Cochrane Handbook before performing a meta-analysis in Review Manager (RevMan) 5.4 software. Four RCTs with 475 patients were included. The results of the meta-analysis showed that the FIR therapy groups had better physiological maturation at 3 months (RR = 1.22; 95% CI = 1.07 to 1.39; p = .002) and clinical maturation at 12 months (RR = 1.35; 95% CI = 1.14 to 1.60; p < .001) than the control groups without FIR therapy. The obstruction rates within 12 months were much lower in the FIR therapy groups than in the control groups (RR = 0.24; 95% CI = 0.08 to 0.68; p = .007), also, there was no statistical heterogeneity. FIR could promote fistula maturation and reduce the incidence of AVF obstruction.

Effects of high-frequency mechanical stimuli on flow related vascular cell biology.

Mechanical forces related to blood pressure and flow patterns play a crucial role in vascular homeostasis. Perturbations in vascular stresses and strain resulting from changes in hemodynamic may occur in pathological conditions, leading to vascular dysfunction as well as in vascular prosthesis, arteriovenous shunt for hemodialysis and in mechanical circulation support. Turbulent-like blood flows can induce high-frequency vibrations of the vessel wall, and this stimulus has recently gained attention as potential contributors to vascular pathologies, such as development of intimal hyperplasia in arteriovenous fistula for hemodialysis. However, the biological response of vascular cells to this stimulus remains incompletely understood. This review provides an analysis of the existing literature concerning the impact of high-frequency stimuli on vascular cell morphology, function, and gene expression. Morphological and functional investigations reveal that vascular cells stimulated at frequencies higher than the normal heart rate exhibit alterations in cell shape, alignment, and proliferation, potentially leading to vessel remodeling. Furthermore, vibrations modulate endothelial and smooth muscle cells gene expression, affecting pathways related to inflammation, oxidative stress, and muscle hypertrophy. Understanding the effects of high-frequency vibrations on vascular cells is essential for unraveling the mechanisms underlying vascular diseases and identifying potential therapeutic targets. Nevertheless, there are still gaps in our understanding of the molecular pathways governing these cellular responses. Further research is necessary to elucidate these mechanisms and their therapeutic implications for vascular diseases.

A prospective study of factors associated with successful maturation of arteriovenous fistulas for hemodialysis.

Our objective was to determine the factors associated with the successful maturation of arteriovenous fistulas during hemodialysis. This prospective study included patients treated with hemodialysis and predialysis patients. Clinical, biochemical, sociodemographic, vascular ultrasound mapping, flow-mediated dilatation, and surgical factors were analyzed. Success in the maturation process was defined by ultrasonographic criteria at six weeks. Thirty-seven patients were included. With a mean ± standard deviation age of 40 ± 14 years, 73% were male, 65% had type-2 diabetes mellitus, and 95% had hypertension. Arteriovenous fistulas were brachycephalic in 18 patients (49%), brachymedian in nine patients (24%), brachycommunicating posterior in five patients (14%), brachibasal in three patients (8%), radiocephalic in two patients (8%), and radiocephalic in two patients (5%). Fourteen percent of patients had unsuccessful maturation. The vein diameter was 4.3 ± 1.0 mm (maturation group) vs 3.2 ± 0.9 mm (non-maturation group), p = 0.04. The artery diameter was similar: 4.5 ± 0.6 vs 4.5 ± 0.4, p = 0.88. Logistic regression analysis revealed that the diameter of the vein for which the surgery was performed was the factor associated with successful maturation in our population, odds ratio = 4.77 (1.14-19.97), p-value = 0.032. It is highly important to plan vascular access in patients to perform vascular mapping and measure veins and arteries in patients. Vein measurement is a significant factor in successful maturation of the arteriovenous fistulas.

Toward a physiological model of vascular wall vibrations in the arteriovenous fistula.

The mechanism behind hemodialysis arteriovenous fistula (AVF) failure remains poorly understood, despite previous efforts to correlate altered hemodynamics with vascular remodeling. We have recently demonstrated that transitional flow induces high-frequency vibrations in the AVF wall, albeit with a simplified model. This study addresses the key limitations of our original fluid-structure interaction (FSI) approach, aiming to evaluate the vibration response using a more realistic model. A 3D AVF geometry was generated from contrast-free MRI and high-fidelity FSI simulations were performed. Patient-specific inflow and pressure were incorporated, and a three-term Mooney-Rivlin model was fitted using experimental data. The viscoelastic effect of perivascular tissue was modeled with Robin boundary conditions. Prescribing pulsatile inflow and pressure resulted in a substantial increase in vein displacement ( %) and strain ( %), with a higher maximum spectral frequency becoming visible above -42 dB (from 200 to 500 Hz). Transitioning from Saint Venant-Kirchhoff to Mooney-Rivlin model led to displacement amplitudes exceeding 10 micrometers and had a substantial impact on strain ( %). Robin boundary conditions significantly damped high-frequency displacement ( %). Incorporating venous tissue properties increased vibrations by 91%, extending up to 700 Hz, with a maximum strain of 0.158. Notably, our results show localized, high levels of vibration at the inner curvature of the vein, a site known for experiencing pronounced remodeling. Our findings, consistent with experimental and clinical reports of bruits and thrills, underscore the significance of incorporating physiologically plausible modeling approaches to investigate the role of wall vibrations in AVF remodeling and failure.

Health-care Professionals' Perspectives on Ultrasound Evaluation of Arteriovenous Hemodialysis Fistula: A Narrative Review.

Arteriovenous hemodialysis fistulas play a critical role in maintaining life on hemodialysis. With the growing use of Doppler ultrasound in nephrology, its utility has expanded to improve the prognosis and quality of life of patients receiving hemodialysis. On a fistula care team, different health-care professionals, including nephrologists, dialysis technicians, and surgeons or vascular interventionalists, require different information. This review article comprehensively explains how Doppler ultrasound evaluation can be beneficial in the management of arteriovenous fistulas from different perspectives of health-care professionals. The article also introduces the pathophysiology of arteriovenous fistula disease and provides a thorough introduction to the use of Doppler ultrasound for the evaluation of arteriovenous fistulas and their associated diseases, addressing the need for a comprehensive understanding among ultrasound practitioners.

The Predictive Significance of Doppler Parameters on the Arteriovenous Fistula Maturation for Hemodialysis-A Single Center Experience.

Doppler ultrasound examination of blood vessels has a significant role in planning and identifying parameters that affect the functioning and maturation of arteriovenous fistula (AVF). Our goal was to determine the predictive parameters of Doppler ultrasound, measured at different time distances, which affect the maturation of AVF for hemodialysis. The research was a retrospective cohort study. The criteria for selecting patients in our study was the existence of information on ultrasound examinations of the lumen of blood vessels before the creation of AVF, as well as lumens of fistula conduits and blood flow measurements, at time intervals of 6-8 weeks and 2-4 months, after the creation of AVF, which we recorded in 105 patients. The respondents were divided into two groups: a group of patients with immature, and mature fistulas. Basic demographic data, clinical characteristics of the responders and laboratory parameters were analyzed. By comparing clinical and laboratory parameters between the group of subjects with and without AVF maturation, a statistically significant difference was determined between the lumen of the proximal radial vein (p = 0.008) and the lumen of the distal radial vein (p = 0.001). The diameter of the fistulous veins (p = 0.037), and the blood flow through the AVF 6-8 weeks (p = 0.001) and 2-4 months (p = 0.001) after its creation were statistically significantly higher in subjects with mature fistulas. By univariate regression analysis, brachial vein (p = 0.04), proximal (p = 0.011) and distal radial artery (p = 0.001), fistula vein, after 6-8 weeks (p = 0.002), blood flow through AVF 6-8 weeks (p = 0.001) and 2-4 months (p = 0.001) after AVF creation, are statistically significant parameters. Predictive parameters of AVF maturation are AVF blood flow after 6-8 weeks (p = 0.010) and AVF blood flow after 2-4 months (p = 0.001). Our research confirmed that greater the blood flow through AVF, at time intervals of 6-8 weeks and 2-4 months after creation, the better the maturation.