Arteriovenous Graft Delamination and Dissection as a Cause of Graft Dysfunction.
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ABSTRACT:
SUBMITTER: Dai R
PROVIDER: S-EPMC7586731 | biostudies-literature | 2020 May
REPOSITORIES: biostudies-literature
Publications
Arteriovenous Graft Delamination and Dissection as a Cause of Graft Dysfunction.
Dai Rui R Broadwell Scott R SR Lessne Mark L ML Kim Charles Y CY
Journal of vascular and interventional radiology : JVIR 20200415 5
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Project description:BackgroundA series of cases have reported graft delamination as a rare complication of early-cannulation arteriovenous graft (ecAVG). The unique multilayer structure of ecAVGs contributes to the property of cannulation as early as hours after implantation, but on other hand it takes the risk of graft delamination. However, the underlying mechanism and management of graft delamination as well as its effects on the long-term patency of ecAVGs have not been systemically analyzed.MethodszA retrospective study was conducted in a cohort of patients who required an ecAVG for hemodialysis (HD) access in our center between April 2017 and December 2021. The characteristics of graft delamination and the outcomes of its different treatments were analyzed.ResultsA total of 144 ecAVGs were established in 141 end-stage renal disease (ESRD) patients, including 124 (86.1%) Acuseal grafts and 20 (13.9%) Flixene grafts. During follow-up 24.5(11.5, 45.8) months, 11 (7.6%) subjects had graft infection with an incidence of 0.03 patient-year. Thirteen (9.0%) subjects had graft delamination at 9.3(5.0,12.4) months after ecAVG implantation, with an incidence of 0.04 per patient-year. ecAVG delamination was observed in both Acuseal grafts (0.037 per patient-year) and Flixene grafts (0.055 per patient-year). Thrombosis or venous hypertension was the most common complaints. Seven delamination was observed at 1.3 (0.1, 4.2) months after an endovascular procedure. The primary patency, primary assistant patency and secondary patency in delamination group were significantly lower than that in non-delamination group (p < 0.05). Post-procedure primary patency of group A (percutaneous transluminal angioplasty, PTA), group B (stenting) and group C (partial graft replacement, PGR) were 1.3 (0.45,4.22) months, 5.3 (3.05,6.85) months and 8.45 (4.78,14.53) months respectively (p = 0.029).ConclusionsGraft delamination was not a rare complication of ecAVGs in this cohort. It significantly reduced the long-term patency of AVGs. PGR might be a more effective therapeutic way than endovascular treatments.
| S-EPMC11552294 | biostudies-literature
Project description:Computational models of aortic dissection can examine mechanisms by which this potentially lethal condition develops and propagates. We present results from phase-field finite element simulations that are motivated by a classical but seldom repeated experiment. Initial simulations agreed qualitatively and quantitatively with data, yet because of the complexity of the problem it was difficult to discern trends. Simplified analytical models were used to gain further insight. Together, simplified and phase-field models reveal power-law-based relationships between the pressure that initiates an intramural tear and key geometric and mechanical factors-insult surface area, wall stiffness, and tearing energy. The degree of axial stretch and luminal pressure similarly influence the pressure of tearing, which was ~88 kPa for healthy and diseased human aortas having sub-millimeter-sized initial insults, but lower for larger tear sizes. Finally, simulations show that the direction a tear propagates is influenced by focal regions of weakening or strengthening, which can drive the tear towards the lumen (dissection) or adventitia (rupture). Additional data on human aortas having different predisposing disease conditions will be needed to extend these results further, but the present findings show that physiologic pressures can propagate initial medial defects into delaminations that can serve as precursors to dissection.
| S-EPMC8957392 | biostudies-literature
Project description:We present a series of kidney transplant dysfunction secondary to lower extremity deep venous thrombosis (DVT). A 70-year-old man underwent living unrelated kidney transplantation and presented 2 months postoperatively with acute kidney injury (AKI) secondary to external iliac vein thrombosis. Graft function improved after endovascular intervention. A 43-year-old man underwent living unrelated kidney transplantation and presented 3 years postoperatively with AKI secondary to external iliac vein thrombosis. Graft function recovered after thrombolysis. A 42-year-old woman underwent simultaneous pancreas and kidney transplantation. Four weeks postoperatively, she had AKI secondary to common femoral vein DVT. Her graft function improved after common iliac vein stenting. A 67-year-old man underwent living unrelated kidney transplantation and presented a week later with lower extremity DVT and AKI. His graft function improved with anticoagulation. Iliofemoral DVT can cause allograft dysfunction. The cause may be multifactorial. Endovascular intervention is safe and feasible when anticoagulation fails.
| S-EPMC6313836 | biostudies-other
Project description:ImportanceInitial hemodialysis access with arteriovenous fistula (AVF) is associated with superior clinical outcomes compared with arteriovenous graft (AVG) and should be the procedure of choice whenever possible. To address the national underuse of AVF in the United States, the Centers for Medicare & Medicaid has established an AVF goal of 66% or greater in 2009.ObjectiveTo explore contemporary practice patterns and physician characteristics associated with high AVG use compared with AVF use.Design, setting, and participantsThis review of 100% Medicare Carrier claims between January 1, 2016, and December 31, 2017, includes both inpatient and outpatient Medicare claims data. All patients undergoing initial permanent hemodialysis access placement with an AVF or AVG were included. All surgeons performing more than 10 hemodialysis access procedures during the study period were analyzed.ExposuresPlacement of an AVF or AVG for initial permanent hemodialysis access.Main outcomes and measuresA surgeon-level AVG (vs AVF) use rate was calculated for all included surgeons. Hierarchical logistic regression modeling was used to identify patient-level and surgeon-level factors associated with AVG use.ResultsA total of 85 320 patients (median age, 70 [range, 18-103] years; 47 370 men [55.5%]) underwent first-time hemodialysis access placement, of whom 66 489 (77.9%) had an AVF and 18 831 (22.1%) had an AVG. Among the 2397 surgeons who performed more than 10 procedures per year, the median surgeon level AVG use rate was 18.2% (range, 0.0%-96.4%). However, 498 surgeons (20.8%) had an AVG use rate greater than 34%. After accounting for patient characteristics, surgeon factors that were independently associated with AVG use included more than 30 years of clinical practice (vs 21-30 years; odds ratio, 0.85 [95% CI, 0.75-0.96]), metropolitan setting (odds ratio, 1.25 [95% CI, 1.02-1.54]), and vascular surgery specialty (vs general surgery; odds ratio, 0.77 [95% CI, 0.69-0.86]). Surgeons in the Northeast region had the lowest rate of AVG use (vs the South; odds ratio, 0.83 [95% CI, 0.73-0.96]). First-time hemodialysis access benchmarking reports for individual surgeons were created for potential distribution.Conclusions and relevanceIn this study, one-fifth of surgeons had an AVG use rate above the recommended best practices guideline of 34%. Although some of these differences may be explained by patient referral practices, sharing benchmarked performance data with surgeons could be an actionable step in achieving more high-value care in hemodialysis access surgery.
| S-EPMC6563590 | biostudies-literature
Project description:ObjectiveThe hemodynamic benefit of novel arteriovenous graft (AVG) designs is typically assessed using computational models that assume highly idealized graft configurations and/or simplified boundary conditions representing the peripheral vasculature. The objective of this study is to evaluate whether idealized AVG models are suitable for hemodynamic evaluation of new graft designs, or whether more realistic models are required.MethodsAn idealized and a realistic, clinical imaging based, parametrized AVG geometry were created. Furthermore, two physiological boundary condition models were developed to represent the peripheral vasculature. We assessed how graft geometry (idealized or realistic) and applied boundary condition models of the peripheral vasculature (physiological or distal zero-flow) impacted hemodynamic metrics related to AVG dysfunction.ResultsAnastomotic regions exposed to high WSS (>7, ≤40 Pa), very high WSS (>40 Pa) and highly oscillatory WSS were larger in the simulations using the realistic AVG geometry. The magnitude of velocity perturbations in the venous segment was up to 1.7 times larger in the realistic AVG geometry compared to the idealized one. When applying a (non-physiological zero-flow) boundary condition that neglected blood flow to and from the peripheral vasculature, we observed large regions exposed to highly oscillatory WSS. These regions could not be observed when using either of the newly developed distal boundary condition models.ConclusionHemodynamic metrics related to AVG dysfunction are highly dependent on the geometry and the distal boundary condition model used. Consequently, the hemodynamic benefit of a novel graft design can be misrepresented when using idealized AVG modelling setups.
| S-EPMC9302782 | biostudies-literature
Project description:Hemodialysis patient survival is dependent on the availability of a reliable vascular access. In clinical practice, procedures for vascular access cannulation vary from clinic to clinic. We investigated the impact of cannulation technique on arteriovenous fistula and graft survival. Based on an April 2009 cross-sectional survey of vascular access cannulation practices in 171 dialysis units, a cohort of patients with corresponding vascular access survival information was selected for follow-up ending March 2012. Of the 10,807 patients enrolled in the original survey, access survival data were available for 7058 patients from nine countries. Of these, 90.6% had an arteriovenous fistula and 9.4% arteriovenous graft. Access needling was by area technique for 65.8%, rope-ladder for 28.2%, and buttonhole for 6%. The most common direction of puncture was antegrade with bevel up (43.1%). A Cox regression model was applied, adjusted for within-country effects, and defining as events the need for creation of a new vascular access. Area cannulation was associated with a significantly higher risk of access failure than rope-ladder or buttonhole. Retrograde direction of the arterial needle with bevel down was also associated with an increased failure risk. Patient application of pressure during cannulation appeared more favorable for vascular access longevity than not applying pressure or using a tourniquet. The higher risk of failure associated with venous pressures under 100 or over 150 mm Hg should open a discussion on limits currently considered acceptable.
| S-EPMC4184025 | biostudies-other
Project description:A 4 year old boy was referred for evaluation of failure to thrive and mild cyanosis. He was found to have a structurally normal heart with evidence of microscopic pulmonary arterio-venous (AV) fistulae. Later, he was diagnosed to have congenital porto-systemic shunt, a very rare cause of pulmonary AV fistula.
| S-EPMC3180992 | biostudies-literature
Project description:A 75-year-old male presented with an immediately threatened grade IIb acute ischemia of the left leg due to thrombosis of a femoro-infrapopliteal prosthetic bypass graft. After an urgent Computed Tomography Angiography, an urgent graft thrombectomy was performed using a 5 Fr Fogarty catheter, which had a troublesome distal passage, causing a tibial A-V fistula.
| S-EPMC8577240 | biostudies-literature
Project description:BackgroundDialysis grafts fail due to recurrent stenosis and thrombosis. Vasoactive and prothrombotic substances affecting intimal hyperplasia or thrombosis may modify graft outcomes.Study designGenetic polymorphisms association study of patients enrolled in a multicenter randomized clinical trial.Setting & participants354 Dialysis Access Consortium (DAC) Study patients receiving a new graft with DNA samples obtained. Participants were randomly assigned to treatment with aspirin plus dipyridamole versus placebo.PredictorDNA sequence polymorphisms for the following candidate genes and their interaction with the study intervention: methylenetetrahydrofolate reductase (MTHFR), heme oxygenase 1 (HO-1), factor V (F5), transforming growth factor β1 (TGFβ1), klotho, nitric oxide synthase (NOS), and angiotensin-converting enzyme (ACE).OutcomeGraft failure (>50% stenosis, angioplasty, thrombosis, surgical intervention, or permanent loss of function).ResultsDuring a median patient follow-up of 34.3 months, 304 grafts failed. After adjusting for clinical factors (patient age, sex, access location, diabetes, cardiovascular disease, baseline aspirin use, body mass index, timing of graft placement, and study treatment) and genetic ancestral background, single-nucleotide polymorphism rs6019 of the factor V gene was associated significantly with graft failure in a dominant model (HR of 1.70 [95% CI, 1.32-2.19; P < 0.001] for G/C and G/G genotypes vs C/C genotypes). There was no significant association between graft failure and polymorphisms of MTHFR, HO-1, TGFβ1, klotho, NOS, or ACE.LimitationsSmall sample size.ConclusionThe rs6019 genotype of Factor V is associated with increased risk of graft failure. Anticoagulation may reduce graft failure in patients with the G/C or G/G genotypes.
| S-EPMC3328616 | biostudies-literature
Project description:ObjectiveCurrent 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.MethodsUsing 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.ResultsAmong 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).ConclusionsFor 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