Arteriovenous Fistula Diameter Research Articles

#336 Early detection of vascular access complication in pediatric CKD hemodialysis patients

Abstract Background and Aims Vascular access (VA) dysfunction is a major clinical complication in the hemodialysis (HD) population and has a direct effect on dialysis outcome. Where in patients undergoing HD, neointimal hyperplasia results in vascular stenosis and subsequent thrombosis, which lead to vascular access failure. Interleukin-10 (IL-10), hs CRP, and tumor necrosis factor- (TNF–α) are inflammatory markers which are proved to be involved in the process neointimal hyperplasia & subsequent complications. We aimed to evaluate the value of these inflammatory markers in early detection of arterio-venous fistula (AVF) failure, in pediatric patients on regular HD, together with the clinical & radiological diagnoses, for proper intervention for correcting AVF failure according to guidelines. Method It was an prospective cohort study, where we included 59 pediatric chronic kidney disease patients’ stage 5, on regular HD (CKD5d), who were following up regularly with us for 1 year. Patients with nonfunctioning AVFs due to complications as thrombus occluding fistula, infections, or large aneurysm, were excluded from the beginning of the study. Monitoring of VA by pre-cannulation physical examination was performed to detect the physical signs of dysfunction, at least once per month according to KDOQI guidelines. Venous pressure (VP) and trans-membrane pressure (TMP) were recorded at each HD session, to detect any abnormalities and to record the pressure changes with the appearance of any AVF complications. Doppler ultrasound (DUS) was performed routinely every 3 months for all HD patients, & at the time of development AVF complications. Blood samples for measuring IL10, TNF, hs CRP were collected from the patients every 2 weeks for 12 months, prior to HD sessions, where we included the most recent samples prior to, and at the time of development complications, which were clinically and radiologically confirmed. Results The mean (±SD) age of our patients was 13.97 (±2.65) years, where we had 39 (56.5%) males, and 30 (43.5%) females, with a median (IQR) HD duration of 4.0 (5.0) years. On assessing the AVF complications, 33 patients (55.9%) had experienced complications, where thrombosis was the most common reported one (17 patients, 28.8%), followed by aneurysm formation in 14 patients (23.7%), while 6 patients (10%) had stenosed AVF, early VA failure in 2 patients (3.4%),1 patient (1.7%) had pseudoaneurysm, and another patient (1.7%) had perivascular hematoma. Mean serum levels of Hs-CRP, TNF-α, IL-10 were elevated at timing of early development of complication, in comparison to their baseline levels, meanwhile serum IL10, and TNF alpha were significantly higher among patients who developed AVF stenosis. The baseline hs-CRP had related positively with AVF diameter at the time of the development of the complications. Conclusion The inflammatory markers have no clinically applied role in early detection of AVF abnormalities, therefore, physical examination and DUS are deemed sufficient.

Technical aspects of percutaneous endovascular arteriovenous fistula creation with the Ellipsys® Vascular Access System. Preliminary results after 16 patients

PurposeTechnical aspects are crucial for planning and performing endovascular arteriovenous fistula (AVF) creation. The Ellipsys® Vascular Access System represents a minimal invasive method for the creation of a proximal forearm fistula. This report summarizes the essential elements for AVF creation with the Ellipsys® Vascular Access System and investigates feasibility, efficacy, and safety procedures conducted on 16 patients.Materials and methodsWe performed a retrospective analysis of patients who underwent endovascular AVF creation with the Ellipsys® Vascular Access System between May 2020 and March 2022 at a tertiary referral center.ResultsThe median age was 67.5 years (47–86 years). The mean BMI was 31.4 kg/m2. AV fistula was created on 15/16 patients on their left arm. The technical success was 100%. The mean operation time was 24.2 min. There were no complications associated with the procedure. All patients were examined after 30 days (± 5 days). Primary patency after 30 days was 94% (15/16). The mean fistula flow was 681.1 mL/min and the mean AVF diameter was 6.1 mm. Thirteen out of 15 patients met the criteria for potential hemodialysis.ConclusionWith the Ellipsys Vascular Access System exist an additional possibility of an AV fistula creation. Based on above findings, the Ellipsys® Vascular Access System represents a feasible, safe, and effective method for AVF creation.

Primary Failure of Autogenous Arteriovenous Fistula: Critical Analysis.

Introduction:Permanent vascular access is an essential intervention in patients with advanced chronic kidney disease (CKD) and its success depends on various non-modifiable and modifiable factors. Considering the element of unpredictability and failure, we attempted to analyze various factors responsible for primary arteriovenous fistula (AVF) failure in presumed high-risk groups.Materials and Methods:We conducted an observational study of newly created AVFs at a tertiary referral government hospital in Eastern India between January 2014 and June 2015. All adult CKD patients undergoing AVF creation were included. Primary AVF failure was assessed at 12 weeks and total follow-up was 24 weeks in presumed high-risk groups of females, patients aged ≥65 years and those with diabetes mellitus.Results:Female gender was at a higher risk of primary AVF failure if aged ≥65 years (P = 0.0026), second AVF creation (P = 0.03), loupe magnification not used (P = 0.03), arterial plaque (P = 0.028), absent immediate thrill, and with radiocephalic AVF (P = 0.02). Absent immediate thrill (<0.0001) and AVF size ≤5 mm (P = 0.002) were important independent risk factors for primary failure. Diabetes or elderly age did not have additional risk, except with uncontrolled hypertension and female gender.Conclusion:Female gender was at a higher risk of poor unassisted AVF patency if their age was ≥65 years, had second AVF creation, loupe magnification not used or if arterial plaque was present. An absence of thrill immediately or at 24 hours or an AVF diameter ≤5 mm were independent intraoperative factors for poor outcome. On the contrary, diabetics, elderly males and intimal thickness were essentially noncontributors for AVF failure, except in few subsets.

SS33. Low-Volume Flows After Balloon-Assisted Maturation Correlate With High Maturation Failures of Arteriovenous Fistulas

Arteriovenous fistula (AVF) is the preferred modality for hemodialysis access, but nearly a third of created AVFs do not mature for successful cannulation. Most of the nonmaturing AVFs require a variety of adjunct procedures (APs) for maturation. The aim of this study was to evaluate the performance of balloon-assisted maturation (BAM) in achieving successful cannulation and to identify predicting factors of maturation after BAM. Patients undergoing BAM for AVF maturation between January 2015 and May 2017 were retrospectively studied. The primary end points were time to maturation and number of subsequent APs needed to achieve maturation. Secondary end points were patency rates after successful cannulation. Of 289 dialysis access creations performed during the study period, 39 AVFs in 37 patients (21 female; median age, 58 years) underwent BAM. They required a total of 66 APs (1.69 per AVF) with a 59% (23/39) maturation rate, with a mean time to successful cannulation of 65 days after the initial AP. There were no significant differences in conduit vein diameter before AVF creation between successful maturation and failure groups (3.30 vs 3.26 mm; P = .96). AVF diameter and volume flows on duplex ultrasound after AVF creation were significantly associated with maturation failure (5.63 mm vs 4.71 mm [P = .034]; 834 vs 556 mL/min [P = .048]). No cutoff value could be established using receiver operating characteristic curve analysis. After BAM, mean time to repeated duplex ultrasound was 90 days from initial creation and 33 days from BAM. AVF diameter was not significantly associated with maturation failure on post-BAM duplex ultrasound (5.88 vs 5.02 mm; P = .13). However, AVF volume flow <500 mL/min on duplex ultrasound after BAM was significantly associated with failure of additional APs and unsuccessful maturation (area under the receiver operating characteristic curve, 0.778; P = .01). As shown in Figs 1 and 2, primary patency at 6 and 12 months was 61% and 52%, respectively. Primary assisted patency was 87% and 61%, respectively. Secondary patency was 96% and 70%, respectively, with 1.47 reinterventions per access year. AVFs requiring BAM as an initial AP can successfully achieve maturation in a majority of cases, but volume flows <500 mL/min after percutaneous transluminal angioplasty are associated with high failure rates despite additional APs.Fig 2Number of arteriovenous fistulas (AVFs) at risk.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Pentosidine in chronic hemodialysis patients: relation with arteriovenous fistula morphology and function.

It has been suggested that advanced glycation end products (AGEs) are involved in atherogenesis, vascular calcification and remodeling, including neointimal hyperplasia, in renal and non-renal patients. Their relevance for arteriovenous fistula (AVF) function has been poorly studied to date, with only one clinical study addressing the issue of thrombosis of vascular access in relation to AGEs in dialysis patients. We aimed to evaluate the relationship between serum pentosidine and AVF morphology and function. Eighty-eighth hemodialysis patients with patent native AVF were included. Ultrasound examination of AVF evaluated blood flow in the brachial artery, resistivity index (RI), the diameter of the vessels and the presence of stenosis. AVF and cardiovascular history were recorded, routine clinical and laboratory evaluation was performed and serum pentosidine was assessed. Forty-eight patients (54.54%) had AVF stenosis. Pentosidine correlated in univariate analysis with cholesterol (r = 0.270, p = 0.01), triglycerides (r = 0.309, p = 0.003), calcium (r = 0.040, p < 0.001) and inversely to dialysis vintage (r = - 0.453, p < 0.001), access vintage (r = - 0.432, p = 0.001), phosphate (r = - 0.211, p = 0.04), parathyroid hormone (r = - 0.211, p = 0.04), urea (r = - 0.230, p = 0.03), residual diameter of AVF (r = - 0.023, p = 0.03). In multivariate regression calcium (p = 0.006), access vintage (p = 0.03), and residual diameter of AVF vein (p = 0.02) remain significantly linked to pentosidine. Patients with pentosidine above median had higher cholesterol (179.91 vs. 160.97, p = 0.04), triglycerides (187.18 vs. 129.31, p = 0.002) and higher prevalence of hypertension (93.70% vs. 84.10%, p = 0.02). Our study suggests that pentosidine could be associated to vascular access morphology and function in dialysis patients.

Association of Preexisting Arterial Intimal Hyperplasia with Arteriovenous Fistula Outcomes.

Preoperative arterial function is associated with arteriovenous fistula (AVF) development. Because arterial pathology may correlate with its function, preexisting arterial intimal hyperplasia may be associated with AVF development. Vascular specimens obtained from 125 patients (with minimal 2 mm arterial diameter and 2.5 mm venous diameter) undergoing AVF creation were quantified for arterial intimal hyperplasia, arterial medial fibrosis, arterial microcalcification, and venous intimal hyperplasia. A 6-week postoperative ultrasound quantified AVF diameter, blood flow, and stenosis. Clinical AVF maturation was assessed using a predefined protocol. In a prospective cohort study design, we investigated the association of preexisting arterial intimal hyperplasia with the postoperative AVF diameter, blood flow, stenosis, and clinical maturation failure, after controlling for baseline demographics, comorbidities, and preoperative vein diameter. Additional analyses evaluated whether other vascular pathologies interacted with arterial intimal hyperplasia in affecting AVF outcomes. The median intimal thickness of the native artery was 22.0 μm (interquartile range, 14.8-37.1 μm). The median postoperative AVF diameter was 4.8 (interquartile range, 3.7-6.8) mm, blood flow was 796 (interquartile range, 413-1036) ml/min, and stenosis was present in 37 out of 98 patients with ultrasound data (38%). AVF nonmaturation occurred in 37 out of 125 patients (30%). Preexisting arterial intimal thickness was not significantly associated with AVF blood flow (-12 ml/min; 95% confidence interval [95% CI], -55 to 30 ml/min), diameter (-0.04 mm; 95% CI, -0.21 to 0.14 mm), stenosis (odds ratio, 0.93; 95% CI, 0.75 to 1.14), or clinical maturation failure (odds ratio, 1.07; 95% CI, 0.90 to 1.28), all per 10 μm increase. There was no significant interaction of preexisting arterial intimal thickness and postoperative AVF outcomes with arterial medial fibrosis, arterial microcalcification, or venous intimal hyperplasia. Preexisting arterial intimal hyperplasia is not associated with the 6-week AVF blood flow, diameter or stenosis, or clinical maturation when the preoperative arterial diameter is ≥2 mm.

Effect of Anti-Hypertensive Medication History on Arteriovenous Fistula Maturation Outcomes

Background: The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis. However, approximately half of AVFs fail to mature. The use of angiotensin converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs), and calcium channel blockers (CCBs) exerts favorable endothelial effects and may promote AVF maturation. We tested associations of ACE-I and ARBs, CCBs, beta-blockers, and diuretics with the maturation of newly created AVFs. Methods: We evaluated 602 participants from the Hemodialysis Fistula Maturation Study, a multi-center, prospective cohort study of AVF maturation. We ascertained the use of each medication class within 45 days of AVF creation surgery. We defined maturation outcomes by clinical use within 9 months of surgery or 4 weeks of initiating hemodialysis. Results: Unassisted AVF maturation failure without intervention occurred in 54.0% of participants, and overall AVF maturation failure (with or without intervention) occurred in 30.1%. After covariate adjustment, CCB use was associated with a 25% lower risk of overall AVF maturation failure (95% CI 3%–41% lower) but a non-significant 10% lower risk of unassisted maturation failure (95% CI 23% lower to 5% higher). ACE-I/ARB, beta-blocker, and diuretic use was not significantly associated with AVF maturation outcomes. None of the antihypertensive medication classes were associated with changes in AVF diameter or blood flow over 6 weeks following surgery. Conclusions: CCB use may be associated with a lower risk of overall AVF maturation failure. Further studies are needed to determine whether CCBs might play a causal role in improving AVF maturation outcomes.

A single treatment, using Far Infrared light improves blood flow conditions in arteriovenous fistula.

A native arteriovenous fistula (AVF) is recommended for angio access in patients on chronic hemodialysis (HD). Fistula patency has been improved by exposure to Far Infrared light (FIR). To investigate whether a single FIR treatment could alter blood velocity, AVF diameter or inflammatory markers. Thirty patients with a native AVF in the forearm were included. Each patient was his/her own control. Ultrasound (US) examinations were performed before and after a single FIR treatment. A single FIR treatment resulted in a significant increase in blood velocity over the AV fistula from a mean of 2.1 ± 1.0 m/s to 2.3 ± 1.0 m/s (p = 0.02). The diameter of the arterialized vein became wider; 0,72 cm ± 0.02 to 0,80 cm ± 0.02, (p = 0.006). The increase in fistula blood velocity correlated positively with base line serum- urate p = 0.004) and the increase in venous diameter with the base line plasma orosomucoid concentration (p = 0.005). This study shows that a single FIR treatment significantly increased AVF blood velocity and vein diameter. Thus, one FIR treatment can help maturation of AVF in the early postoperative course.

Association between Preoperative Vascular Function and Postoperative Arteriovenous Fistula Development.

Arteriovenous fistula (AVF) maturation failure is the primary cause of dialysis vascular access dysfunction. To evaluate whether preoperative vascular functional properties predict postoperative AVF measurements, patients enrolled in the Hemodialysis Fistula Maturation Study underwent up to five preoperative vascular function tests (VFTs): flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), carotid-femoral pulse wave velocity, carotid-radial pulse wave velocity, and venous occlusion plethysmography. We used mixed effects multiple regression analyses to relate each preoperative VFT to ultrasound measurements of AVF blood flow rate and venous diameter at 1 day, 2 weeks, and 6 weeks after AVF placement. After controlling for AVF location, preoperative ultrasound measurements, and demographic factors (age, sex, race, and dialysis status), greater NMD associated with greater 6-week AVF blood flow rate and AVF diameter (per absolute 10% difference in NMD: change in blood flow rate =14.0%; 95% confidence interval [95% CI], 3.7% to 25.3%; P<0.01; change in diameter =0.45 mm; 95% CI, 0.25 to 0.65 mm; P<0.001). Greater FMD also associated with greater increases in 6-week AVF blood flow rate and AVF diameter (per absolute 10% difference in FMD: change in blood flow rate =11.6%; 95% CI, 0.6% to 23.9%; P=0.04; change in diameter =0.31 mm; 95% CI, 0.05 to 0.57 mm; P=0.02). None of the remaining VFT parameters exhibited consistent statistically significant relationships with both postoperative AVF blood flow rate and diameter. In conclusion, preoperative NMD and FMD positively associated with changes in 6-week AVF blood flow rate and diameter, suggesting that native functional arterial properties affect AVF development.

Abstract 625: Adipose-Associated Mediators Correlate with Anatomic and Physiologic Adaptations Following Fistula Placement: The Hemodialysis Fistula Maturation (HFM) Study

Introduction: Perivascular inflammation stands as an important regulator of vascular remodeling. We hypothesize that the phenotype of adipose tissue adjacent to a hemodialysis arteriovenous fistula (AVF) modulates the anatomy and physiology of maturation. Methods: During AVF creation, adipose tissue adjacent to the vein was collected from 112 participants in the NIDDK HFM Study, and 9 adipose-associated mediator protein levels were measured. AVF duplex ultrasound was performed post-operatively at Day 1, and Weeks 2 and 6, and prior to 1 st cannulation (Week 10-22) to define the changes in diameter and flow. Associations between biomarker levels and fistula remodeling were evaluated using mixed effects regression analyses. Results: Fractional changes in vein diameter decrease with increasing IL-6 and MCP-1 levels; changes in AVF flow decrease with increasing leptin ( A ). IL-6 demonstrated a statistically significant relationship with vein adaptations in the early time frame (1D-2W), but not in the later stages of remodeling ( B ). Additional interaction effects between concentration and diameter/flow changes were identified, with elevated inflammatory biomarker levels correlated with reduced early and peri-anastomotic changes in vein diameter and flow ( C ). Conclusions: Changes in AVF diameter and flow are associated with baseline local adipose phenotype. Impaired vein dilation and reduced capacity for flow augmentation appears related to enhanced inflammation, particularly at early times and in the peri-anastomotic region.

Effect of Far Infrared Therapy on Arteriovenous Fistula Maturation: An Open-Label Randomized Controlled Trial

Malfunction of the arteriovenous fistula (AVF) is an important cause of morbidity and hospitalization in hemodialysis (HD) patients. The aim of this study is to evaluate the effect of far infrared therapy on the maturation and patency of newly created AVFs in patients with chronic kidney disease stage 4 or 5. Randomized controlled study. Patients with estimated glomerular filtration rate of 5-20 mL/min/1.73 m². 40 minutes of far infrared therapy 3 times weekly for a year. The primary outcome is the rate of AVF malfunction within 12 months, with malfunction defined as either: (1) thrombosis without thrill for AVFs not undergoing HD or (2) receiving any type of interventional procedure due to a lower Kt/V (<1.2) for patients undergoing HD. Secondary outcomes include: (1) cumulative primary unassisted AVF patency, defined as time from creation of the AVF to the first episode of AVF malfunction; (2) physiologic maturation of the AVF by the definition of AVF access blood flow (Qa) ≥500 mL/min and AVF diameter ≥4 mm at 3 months; and (3) clinical maturation of the AVF suitable for HD at 1 year. AVF Qa was measured by Doppler ultrasonography at 2 days and 1, 2, 3, and 12 months. We enrolled 122 patients who were randomly allocated to the intervention (n = 60) and control (n = 62) groups. In comparison to controls, patients in the intervention group had higher Qa values at 1, 2, 3, and 12 months; a higher rate of physiologic maturation (90% vs 76%; P = 0.04) at 3 months; and a lower rate of AVF malfunction (12% vs 29%; P = 0.02) but higher rates of AVF cumulative unassisted patency (87% vs 70%; P = 0.01) and clinical maturation (82% vs 60%; P = 0.008) within 12 months. This is a single-center nonblinded study. Far infrared therapy improves the access flow, maturation, and patency of newly created AVFs in patients with chronic kidney disease stages 4 and 5.

Fistula Salvage by Endovascular Therapy

Fistulas are considered superior to synthetic grafts as a hemodialysis vascular access; however, fistulas are not without problems. To maximize the number of fistulas being used in prevalent patients, it is important to have a program designed to salvage early failures or fistulas that fail to mature and those that become dysfunctional during the course of usage. Endovascular techniques have proven to be very effective in the management of both of these problems. These fistulas should be aggressively evaluated and treated because treatment carries with it a high expectation of successful salvage of what would have otherwise been an abandoned access.