New Approaches to Arteriovenous Fistula Creation.
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ABSTRACT:
SUBMITTER: Rajan DK
PROVIDER: S-EPMC4803508 | biostudies-literature | 2016 Mar
REPOSITORIES: biostudies-literature
Publications
New Approaches to Arteriovenous Fistula Creation.
Seminars in interventional radiology 20160301 1
An autogenous arteriovenous fistula is considered the ideal access for hemodialysis delivery. However, surgical creation of an arteriovenous fistula is associated with less than optimal technical success, and multiple interventions are often required to assist maturation or maintain early patency. Given these shortcomings, multiple new approaches are now under investigation that possibly improve on surgical techniques and/or outcomes. Minimally invasive methods of creation with novel devices are ...[more]
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Project description:Stenosis from venous neointimal hyperplasia is common in native arteriovenous fistulas (AVFs). However, the preexisting histologic characteristics of veins at fistula creation, and associations thereof with baseline patient factors, have not been well characterized. In this study, we conducted histologic analysis of a segment of the vein used for anastomosis creation, obtained during AVF creation from 554 of the 602 participants in the multicenter Hemodialysis Fistula Maturation Cohort Study. We quantified intimal and medial areas and lengths of the internal and external elastic lamina by morphometry and assessed venous wall cells by immunohistochemistry, extracellular matrix with Movat stain, and calcium deposition by alizarin red stain. We also studied a representative subset of veins for markers of monocyte/macrophage content, cell proliferation, apoptosis, and neoangiogenesis. Neointima occupied >20% of the lumen in 57% of fully circumferential vein samples, and neointimal hyperplasia associated positively with age and inversely with black race. The neointima was usually irregularly thickened, sometimes concentric, and contained ?-smooth muscle actin-expressing cells of smooth muscle or myofibroblast origin. Proteoglycans admixed with lesser amounts of collagen constituted the predominant matrix in the neointima. In 82% of vein samples, the media of vessel walls contained large aggregates of collagen. A minority of veins expressed markers of inflammation, cell proliferation, cell death, calcification, or neoangiogenesis. In conclusion, we observed preexisting abnormalities, including neointimal hyperplasia and prominent accumulation of extracellular matrix, in veins used for AVF creation from a substantial proportion of this cohort.
| S-EPMC5619951 | biostudies-literature
Project description:To assess the anatomic development of native arteriovenous fistula (AVF) during the first 6 weeks after creation by using ultrasonographic (US) measurements in a multicenter hemodialysis fistula maturation study.Each institutional review board approved the prospective study protocol, and written informed consent was obtained. Six hundred and two participants (180 women and 422 men, 459 with upper-arm AVF and 143 with forearm AVF) from seven clinical centers underwent preoperative artery and vein US mapping. AVF draining vein diameter and blood flow rate were assessed postoperatively after 1 day, 2 weeks, and 6 weeks. Relationships among US measurements were summarized after using multiple imputation for missing measurements.In 55% of forearm AVFs (68 of 124) and 83% of upper-arm AVFs (341 of 411) in surviving patients without thrombosis or AVF intervention prior to 6 weeks, at least 50% of their 6-week blood flow rate measurement was achieved at 1 day. Among surviving patients without thrombosis or AVF intervention prior to week 2, 70% with upper-arm AVFs (302 of 433) and 77% with forearm AVFs (99 of 128) maintained at least 85% of their week 2 flow rate at week 6. Mean AVF diameters of at least 0.40 cm were seen in 85% (389 of 459), 91% (419 of 459), and 87% (401 of 459) of upper-arm AVFs and in 40% (58 of 143), 73% (104 of 143), and 77% (110 of 143) of forearm AVFs at 1 day, 2 weeks, and 6 weeks, respectively. One-day and 2-week AVF flow rates and diameters were used to predict 6-week levels, with 2-week prediction of 6-week measures more accurate than those of 1 day (flow rates, R(2) = 0.47 and 0.61, respectively; diameters, R(2) = 0.49 and 0.82, respectively).AVF blood flow rate at 1 day is usually more than 50% of the 6-week blood flow rate. Two-week measurements are more predictive of 6-week diameter and blood flow than those of 1 day. US measurements at 2 weeks may be of value in the early identification of fistulas that are unlikely to develop optimally.
| S-EPMC4851120 | biostudies-literature
Project description:Introduction:Local inflammation is an important regulator of vascular remodeling. We hypothesized that adipose tissue adjacent to hemodialysis arteriovenous fistulae modulates maturation. Methods:During fistula creation, perivenous adipose was collected from 111 participants in the Hemodialysis Fistula Maturation Study. Nine adipose-associated mediators were measured. Duplex ultrasound was performed at 4 time points postoperatively from 1 day to first cannulation (10-26 weeks). Associations between logarithmically transformed biomarker levels and fistula remodeling were evaluated using mixed effects regression. Results:Elevated interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 were associated with a reduction in the fractional vein diameter during the early time frame of 1 day to 2 weeks (diameter change of 26.6% and 20.4% at the 25th and 75th percentile for IL-6, P = 0.01; 27.8% and 21.1% at the 25th and 75th percentile for MCP-1, P = 0.02), but not in later stages of remodeling. Local leptin levels showed a significant negative correlation with fractional venous flow increase between 2 and 6 weeks (percent flow change 31.4% and 11.3% at the 25th and 75th percentile for leptin, P = 0.03). Conclusion:Thus, impaired fistula vein dilation and reduced capacity for flow augmentation associate with specific local adipose phenotypic signatures in a time-dependent manner. In view of adipose tissue plasticity, these findings raise the possibility of novel adipose-based strategies to facilitate fistula maturation.
| S-EPMC6035127 | biostudies-literature
Project description:BACKGROUND:An arteriovenous fistula is the optimal form of vascular access in patients with end-stage renal failure requiring haemodialysis. Unfortunately, approximately one-third of fistulae fail at an early stage. Different anaesthetic techniques can influence factors associated with fistula success, such as intraoperative blood flow and venous diameter. A regional anaesthetic brachial plexus block results in vasodilatation and improved short- and long-term fistula flow compared to the infiltration of local anaesthetic alone. This, however, has not yet been shown in a large trial to influence long-term fistula patency, the ultimate clinical measure of success.The aim of this study is to compare whether a regional anaesthetic block, compared to local anaesthetic infiltration, can improve long-term fistula patency. METHODS:This study is an observer-blinded, randomised controlled trial. Patients scheduled to undergo creation of either brachial or radial arteriovenous fistulae will receive a study information sheet, and consent will be obtained in keeping with the Declaration of Helsinki. Patients will be randomised to receive either: (i) an ultrasound guided brachial plexus block using lignocaine with adrenaline and levobupivicaine, or (ii) local anaesthetic infiltration with lignocaine and levobupivicaine.A total of 126 patients will be recruited. The primary outcome is fistula primary patency at three months. Secondary outcomes include primary patency at 1 and 12 months, secondary patency and fistula flow at 1, 3 and 12 months, flow on first haemodialysis, procedural pain, patient satisfaction, change in cephalic vein diameter pre- and post-anaesthetic, change in radial or brachial artery flow pre- and post-anaesthetic, alteration of the surgical plan after anaesthesia as guided by vascular mapping with ultrasound, and fistula infection requiring antibiotics. CONCLUSIONS:No large randomised controlled trial has examined the influence of brachial plexus block compared with local anaesthetic infiltration on the long-term patency of arteriovenous fistulae. If the performance of brachial plexus block increases fistulae patency, this will have significant clinical and financial benefits as the number of patients able to commence haemodialysis when planned should increase, and the number of "redo" or revision procedures should be reduced. TRIAL REGISTRATION:This study has been approved by the West of Scotland Research Ethics Committee 5 (reference no. 12/WS/0199) and is registered with the ClinicalTrials.gov database (reference no. NCT01706354).
| S-EPMC3765116 | biostudies-literature
Project description:Current guidelines suggest that arteriovenous fistula (AVF) is associated with survival advantage over arteriovenous graft (AVG). However, AVFs often require months to become functional, increasing tunneled dialysis catheter (TDC) use, which can erode the benefit of an AVF. We sought to compare survival in patients with end-stage renal disease after creation of an AVF or AVG in patients starting hemodialysis (HD) with a TDC and to identify patient populations that may benefit from preferential use of AVG over AVF.Using U.S. Renal Data System databases, we identified incident HD patients in 2005 through 2008 and observed them through 2008. Initial access type and clinical variables including albumin levels were assessed using U.S. Renal Data System data collection forms. Attempts at AVF and AVG creation in patients who started HD through a TDC were identified by Current Procedural Terminology codes. We accounted for the effect of changes in access type by truncating follow-up when an additional AVF or AVG was performed. Survival curves were then constructed, and log-rank tests were used for pairwise survival comparisons, stratified by age. Multivariate analysis was performed with Cox proportional hazards regressions; variables were chosen using stepwise elimination. An interaction of access type and albumin level was detected, and Cox models using differing thresholds for albumin level were constructed. The primary outcome was survival.Among the 138,245 patients who started with a TDC and had complete records amenable for analysis, 22.8% underwent AVF creation (mean age ± standard deviation, 68.9 ± 12.5 years; 27.8% mortality at 1 year) and 7.6% underwent AVG placement (70.2 ± 12.0 years; 28.2% mortality) within 3 months of HD initiation; 69.6% remained with a TDC (63.2 ± 15.4 years; 33.8% mortality). In adjusted Cox proportional hazards regression, AVF creation is equivalent to AVG placement in terms of survival (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.93-1.02; P = .349). AVG placement is superior to continued TDC use (HR, 1.54; 95% CI, 1.48-1.61; P < .001). In patients older than 80 years with albumin levels >4.0 g/dL, AVF creation is associated with higher mortality hazard compared with AVG creation (HR, 1.22; 95% CI, 1.04-1.43; P = .013).For patients who start HD through a TDC, placement of an AVF and AVG is associated with similar mortality hazard. Further study is necessary to determine the ideal access for patients in whom the survival advantage of an AVF over an AVG is uncertain.
| S-EPMC4659732 | biostudies-literature
Project description:BackgroundArteriovenous fistula (AVF) is the vascular access of choice for patients on hemodialysis. Recent evidence suggests that AVF creation may slow estimated glomerular filtration rate (eGFR) decline. The study objective was to assess the impact of the AVF creation on eGFR decline, after controlling for key confounding factors.MethodsThis retrospective cohort study included adult patients followed in a single-center predialysis clinic between 1999 and 2016. Patients with a patent AVF were followed up to 2 years pre- and post-AVF creation. Estimated GFR trajectory was reported using linear mixed models adjusted for demographic characteristics, comorbidities and use of renin-angiotensin-aldosterone blockade.ResultsA total of 146 patients were studied with a median age 68.7 (60.5-75.4) years and a median eGFR at time of AVF creation of 12.8 (11.3-13.9) mL/min/1.73m2. The crude annual eGFR decline rates were?-?3.60?±?4.00?mL/min/1.73?m2 pre- and?-?2.28?±?3.56?mL/min/1.73?m2 post-AVF, resulting in a mean difference of 1.28?mL/min/1.73?m2 (95% CI 0.49, 2.07). In a mixed effect linear regression model, monthly eGFR decline was -?0.63 (95% CI -0.81, -?0.46; p?<? 0.001) mL/min/1.73m2/month. The period after AVF creation was associated with a relatively higher eGFR (? 0.94, 95% CI 0.61-1.26, p?<? 0.001). There was a significant association between follow-up time and the period pre/post AVF (? 0.19, 95% CI 0.16, 0.22; p?<? 0.001) such that eGFR decline was more attenuated each month after AVF creation.ConclusionsIn this cohort, AVF creation was associated with a significant reduction of eGFR decline. Further prospective studies are needed to confirm this association.
| S-EPMC6876290 | biostudies-literature
Project description:BackgroundArticaine has emerged as a local anesthetic (LA) that produces sensory and motor blockade shorter than bupivacaine and lower in neurotoxicity than lidocaine. Studies have shown that adding dexmedetomidine to LA produces prolongation of sensory and motor bock duration. Early regain of motor power with adequate analgesia is needed in hemodialysis fistula creation surgery, for early start of physiotherapy. We designed this study to test efficacy of adding dexmedetomidine to articaine on the duration of sensory and motor block.MethodsAfter university review board approval, written informed consent to participate in the study was obtained. Patients with chronic renal failure undergoing radiocephalic hemodialysis fistula creation were eligible for enrollment in this double-blind, randomized trial. Patients receive either 40 ml of 2% articaine hydrochloride or 40 ml of articaine 2% mixed with dexmedetomidine (1 ?g.kg - 1). Sensory block duration in minutes is assessed by pinprick test and motor block duration in minutes is tested by Bromage scale; both are recorded as a primary outcome. Secondary outcomes, including onset of sensory and motor block, time for rescue analgesia, hemodynamic changes, oversedation, and possible side effect, were recorded.ResultsFifty patients were enrolled in the study (25 in the articaine Group A and 25 in the articaine and dexmedetomidine group [AD]). Longer sensory block duration was in Group AD (230-260 min) than in Group A (172-185 min) with P < 0.001. In addition, motor block duration was significantly longer in Group AD than in Group A, (220 ± 110 min), (165 ± 45 min), respectively. The duration of effective analgesia was significantly longer in Group AD (363 ± 134 min) versus in Group A (244 ± 84 min). The onset of block was short and similar between groups.ConclusionAddition of dexmedetomidine to articaine during arteriovenous fistula creation provide prolongation of sensory and motor block duration and augment analgesia.Trial registrationThis trial was registered at Clinical trial.gov https://clinicaltrials.gov/ct2/show/NCT04171349 with the identification number NCT04171349.
| S-EPMC7819413 | biostudies-literature
Project description:Preoperative assessment prior to surgical arteriovenous fistulas (AVFs) including ultrasound-guided mapping has been shown to have beneficial effects on their immediate success as well as early outcomes. This has led to their wide acceptance and adoption however clinical practice criteria is variable and is reflected in variabilities in practice. When transposing this to percutaneously created endovascular AVFs (endoAVFs), variable preoperative assessment criteria could equally result in variable practice and potentially subsequent and expectant outcomes. We aimed to review literature on reported validated methodologies and workflows of preoperative assessment for surgical AVF creation as reported in highest levels of available evidence, specifically randomized controlled trials. Published practice recommendations and guidelines on best clinical practice as well as systematic reviews and meta-analyses of published studies were also reviewed. Data on practice methodology from identified trial publications and protocols was collated and a summative narrative synthesis was carried out which compared these methodologies to additional assessments that may be required when targeting assessment for percutaneous endoAVF formation, based on our units experience as part of an international multicentre trial. In this review we present a brief overview of published literature and guidelines and propose a unified and uniform workflow for preoperative assessment for surgical AVFs and endoAVFs to aide clinical and imaging practice.
| S-EPMC7857810 | biostudies-literature
Project description: Not available
| S-EPMC7683226 | biostudies-literature
Project description:BackgroundThe arteriovenous fistula (AVF) is the preferred hemodialysis access for end-stage renal disease (ESRD) patients. Yet, establishment of a functional AVF presents a challenge, even for the most experienced surgeons, since postoperative stenosis frequently occludes the AVF. Stenosis results from the loss of compliance in fibrotic areas of the fistula which turns intimal hyperplasia into an occlusive feature. Fibrotic remodeling depends on deposition and crosslinking of collagen by lysyl oxidase (LOX), an enzyme that catalyzes the deamination of lysine and hydroxylysine residues, facilitating intra/intermolecular covalent bonds. We postulate that pharmacological inhibition of lysyl oxidase (LOX) increases postoperative venous compliance and prevents stenosis in a rat AVF model.MethodsLOX gene expression and vascular localization were assayed in rat AVFs and human pre-access veins, respectively. Collagen crosslinking was measured in humans AVFs that matured or failed, and in rat AVFs treated with β-aminopropionitrile (BAPN), an irreversible LOX inhibitor. BAPN was either injected systemically or delivered locally around rat AVFs using nanofiber scaffolds. The major endpoints were AVF blood flow, wall fibrosis, collagen crosslinking, and vascular distensibility.ResultsNon-maturation of human AVFs was associated with higher LOX deposition in pre-access veins (N=20, P=0.029), and increased trivalent crosslinks (N=18, P=0.027) in human AVF tissues. Systemic and local inhibition of LOX increased AVF distensibility, while reducing wall fibrosis and collagen crosslinking in rat fistulas.ConclusionsOur results demonstrate that BAPN-mediated inhibition of LOX significantly improves vascular remodeling in experimental fistulas.
| S-EPMC8315119 | biostudies-literature