Access In Hemodialysis Patients Research Articles

Endothelial TGF-β Signaling Regulates Endothelial-Mesenchymal Transition During Arteriovenous Fistula Remodeling in Mice With Chronic Kidney Disease.

Arteriovenous fistulae (AVFs) are the preferred vascular access for hemodialysis in patients with end-stage kidney disease. Chronic kidney disease (CKD) is associated with endothelial injury, impaired AVF maturation, and reduced patency, as well as utilization. Because CKD is characterized by multiple pathophysiological processes that induce endothelial-to-mesenchymal transition (EndMT), we hypothesized that CKD promotes EndMT during venous remodeling and that disruption of endothelial TGF (transforming growth factor)-β signaling inhibits EndMT to prevent AVF failure even in the end-stage kidney disease environment. The mouse 5/6 nephrectomy and aortocaval fistula models were used. CKD was created via 5/6 nephrectomy, with controls of no (0/6) or partial (3/6) nephrectomy in C57BL/6J mice. AVFs were created in mice with knockdown of TGF-βR1/R2 (TGF-β receptors type 1/2) in either smooth muscle cells or endothelial cells. AVF diameters and patency were measured and confirmed by serial ultrasound examination. AVF, both murine and human, were examined using Western blot, histology, and immunofluorescence. Human and mouse endothelial cells were used for in vitro experiments. CKD accelerates TGF-β activation and promotes EndMT that is associated with increased AVF wall thickness and reduced patency in mice. Inhibition of TGF-β signaling in both endothelial cells and smooth muscle cells decreased smooth muscle cell proliferation in the AVF wall, attenuated EndMT, and was associated with reduced wall thickness, increased outward remodeling, and improved AVF patency. Human AVF also showed increased TGF-β signaling and EndMT. CKD promotes EndMT and reduces AVF patency. Inhibition of TGF-β signaling, especially disruption of endothelial cell-specific TGF-β signaling, attenuates EndMT and improves AVF patency in mouse AVF. Inhibition of EndMT may be a therapeutic approach of translational significance to improve AVF patency in human patients with CKD.

Comprehensive Nursing Care for Vascular Access in Hemodialysis Patients with End-Stage Renal Disease

With lifestyle and dietary changes, the number of kidney disease patients in China is rising. For end-stage renal disease (ESRD) patients, long-term hemodialysis is crucial for survival, requiring reliable vascular access. This review summarizes the essential nursing care for vascular access in ESRD, focusing on preoperative and postoperative strategies, psychological support, physical preparation, fistula maturity assessment, and puncture techniques. It also addresses common complications and their management. Integrating new technologies with traditional nursing practices can enhance treatment outcomes, reduce complications, and improve the quality of life for hemodialysis patients, underscoring the vital role of skilled nursing in ESRD care.

Outcome of upper limb arteriovenous prosthetic graft versus lower limb arteriovenous access for hemodialysis in patients with exhausted vascular accesses

Outcome of upper limb arteriovenous prosthetic graft versus lower limb arteriovenous access for hemodialysis in patients with exhausted vascular accesses

Effect of blood viscosity on the hemodynamics of arteriovenous fistulae based on numerical investigation

Arteriovenous fistula (AVF) is the most commonly used vascular access for hemodialysis in patients with end-stage renal disease. Vascular diseases such as atherosclerosis and thrombosis, triggered by altered hemodynamic conditions, are the main causes of access failure. Changes in blood viscosity accelerate access dysfunction by affecting local velocities and wall shear stress (WSS) distribution in the circulation. Numerical simulation was employed to analyze and compare the hemodynamic behavior of AVF under different blood viscosities (0.001–0.012 Pa∙s). An idealized three-dimensional model with end-to-side anastomosis was established. Transient simulations were conducted using pulsatile inlet velocity and outflow as boundary conditions. The simulation results reveal the blood flow state of AVF under different viscosity physiological conditions and derive the rule of change. When blood viscosity increases, the local velocity in the disturbed region slows down and the stagnation time becomes longer, resulting in increased deposition of substances. As blood viscosity increases, the level of shear stress on the entire wall of the fistula increases accordingly. WSS values at high viscosities above 0.007 Pa∙s showed significantly larger low-shear regions near the anastomosis and increased chances of inducing atheromatous plaques. This research has revealed the correlation between blood dynamic viscosity and the hemodynamic behavior of AVF. Elevated whole blood viscosity increases the incidence of access obstruction and vascular disease leading to fistula failure. The study provides a basis for optimizing the distribution of hemodynamic parameters in the fistula for hemodialysis patients.

Hand ischemia in patients undergoing renal replacement therapy: assessment by thermography

Hand ischemia in patients undergoing renal replacement therapy: assessment by thermography

Predicting factors for early failure of vascular access in hemodialysis patients.

This study aimed to investigate the incidence of early failure of vascular access for hemodialysis, and determine which factors measured in duplex ultrasound study could predict early failure. We performed a retrospective review of patients who underwent arteriovenous fistula (AVF) or arteriovenous graft (AVG) creation for hemodialysis between September 2019 and January 2023. Early failure was defined as any event that required surgical or endovascular intervention within 6 months following AVF or AVG creation. A total of 189 patients were included. Early failure occurred in 36 patients (19.0%), which included 22 AVFs and 14 AVGs. In the patients who underwent AVF, the preoperative venous diameter, postoperative venous and arterial diameters, and flow volume of AVF all were significantly smaller in the early failure group compared to the patent group. In AVG, the preoperative venous diameter was the only parameter that differed between the 2 groups. A sonographic score was defined based on these factors. In a multivariable analysis, male sex, a previous history of AVF or AVG creation, and sonographic score were found to be significantly associated with early failure. The postoperative venous diameter in AVF and the preoperative venous diameter in AVG were highly predictive of early failure (areas under the curves 0.92 and 0.82, respectively). Venous diameter measured 6 weeks following AVF operation and preoperative venous diameter in AVG were highly predictive of early failure among the duplex ultrasound parameters. Surveillance strategies in the early phase following vascular access creation can be based on these factors.

Recurrent arteriovenous fistula thrombosis: The role of genetic mutations and hyperhomocysteinemia – a clinical case

Thrombophilia denotes an increased predisposition to the formation of blood clots within blood vessels, stemming from genetic or acquired abnormalities in the hemostasis system. The challenge of establishing durable vascular access for hemodialysis in patients is compounded by various detrimental factors affecting the vascular wall, with vascular wall remodeling and hemostasis system disruptions being paramount among them. This clinical case report outlines our findings in a rare instance of recurrent thrombosis in an arteriovenous fistula.
 The objective of this study is to present a clinical case involving repeated arteriovenous fistula thrombosis in a patient with chronic kidney disease, exacerbated by a confluence of hyperhomocysteinemia and mutations in hemostasis-related genes: F13A1 (103G>T) (heterozygous carrier of blood coagulation factor XIII), FGB-fibrinogen (455G>A) (heterozygous carrier of coagulation factor I), and Serpin1 (PAI-1) (675 5G>4G) (homozygous carrier of tissue plasminogen activator antagonist). Additionally, we aim to illustrate the diagnostic exploration for coagulopathy causes in cases of chronic recurrent thrombosis, emphasizing the importance of utilizing modern genetic tests for diagnosing thrombophilias and urging healthcare professionals to consider these advanced diagnostic possibilities.

#3736 SACUBITRIL/VALSARTAN IMPROVES THE VASCULAR ACCESS FLOW OF HEMODIALYSIS PATIENTS WITH HEART FAILURE AND REDUCED EJECTION FRACTION

Abstract Background and Aims Sacubitril/valsartan improved left ventricular systolic and diastolic function in patients with heart failure with reduced ejection fraction<40% (HFrEF) and end-stage kidney disease. However, there was no report concerning the effect of sacubitril/valsartan on access flow (Qa) of vascular access in maintenance hemodialysis (HD) patients with HFrEF. We aimed to investigate the effect of sacubitril/valsartan on Qa of vascular access in HD patients with HFrEF. Method We retrospectively screened the HD patients who received echocardiogram and Qa measurement in Taipei Veterans General Hospital and Cheng Hsin General Hospital from Jan. 2019 to Dec. 2021. Patients with HFrEF received twice of both echocardiography and Qa at 1 year apart were enrolled and divided into two groups, including those with or without the treatment of sacubitril/valsartan. The difference of Qa at baseline and 1 year later was compared by Wilcoxon signed-rank test, with a statistical significance of P<0.05. Results A total of 33 HD patients with HFrEF were analyzed with a mean HD vintage of 4.7 years. Sixteen patients received sacubitril/valsartan and the other 17 patients received conventional treatment. The mean Qa increased significantly from 633.8 to 948.8 mL/min (P<0.001) and the Qa change correlated with LVEF change [Fig. 1. correlation coefficient (r) =0.70, P=0.006] after 1-year treatment of sacubitril/valsartan; however, there was neither significant change of Qa (from 637.7 to 621.8 mL/min, P=0.44) nor correlation with LVEF change (Fig. 2, r=0.41, P=0.13) for controls after one year. Conclusion Sacubitril/Valsartan improves Qa in HD patients with HFrEF possibly related to the increase of LVEF.

#5657 FRAILTY AND VASCULAR ACCESS IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Frailty is a geriatric syndrome characterized by increased vulnerability to stressors. The elderly become vulnerable and susceptible to adverse outcomes for their health and to functional restrictions. Previous guidelines suggested fistula creation as first choice for vascular access. Current guidelines suggest a more tailored approach to the patient's needs. Despite the high prevalence of frailty in hemodialysis patients, there is paucity of work investigating the relationship between frailty and vascular access failure. The aim of the study was the estimation of frailty with different scores and relationship with the choice of first vascular access, the current vascular access and vascular failures. Method 67 patients in hemodialysis participated to the study (observational cross-sectional study). Frailty was assessed with 6 different scores,Clinical Frailty Scale (CFS), Frailty Phenotype (FP), Edmonton Frailty Scale (EFS), Groningen Frailty Index GFI), Short Physical Performance Battery (SPPB), Prisma-7 and ankle-brachial index (ABI) and hand grip were also estimated. The current vascular access, the first vascular access, the vascular access failures and the mean duration of the vascular accesses were also recorded. Finally, the levels of the hemoglobin, serum albumin, C reactive protein, cholesterol were measured for all patients and the hemodialysis adequacy (URR, sp Kt/V) was calculated from the levels of urea before and after the hemodialysis session. Finally, the levels of the hemoglobin, albumin, C reactive protein, cholesterol were measured for all patients and the hemodialysis adequacy was calculated from the levels of urea before and after the hemodialysis session. Results The first vascular access of hemodialysis presents statistically significant relation between frail and robust patients that start hemodialysis with central venus catheter and AVF-AVG respectively. (SPPB- tunneled CVC 85, 7%, non tunneled CVC 46,2% ρ=0,032, Prisma-7- frail tunneled CVC 100%, non tunneled CVC 76,9% ρ=0,018, Groningen FI -frail tunneled CVC 100%, non tunneled CVC 65,7% ρ=0,011, Εdmonton FS -AVF-AVG not frail 64,7%, vulnerable 20,6% ρ=0,042) (Table 1-4). ABI presented a statistically significant relationship with the current vascular access. 68,18% of the patients with normal ABI have AVF-AVG and 60,87% of patients with abnormal ABI have tunneled CVC (p=0,022). In addition, the number of vascular accesses per patient, the mean duration of the accesses and the premature failures (3 months after creation) don't present statistically significant relation with frailty. Conclusion The frailty score could be used as a tool for the choice of vascular access in hemodialysis patients. Further studies, in a larger number of patients, are required to define a reliable and easy to use frailty tool, which is best suited to dialysis access selection.

#6597 THE EFFECT OF PATHOGEN ON THE OUTCOME OF HEMODIALYSIS CATHETER-RELATED BLOODSTREAM INFECTIONS IN HOSPITALIZED PATIENTS: A SINGLE CENTER ANNUAL RECORD

Abstract Background and Aims Tunneled double-lumen catheters are increasingly used as permanent vascular access in hemodialysis patients, particularly in those with limited vascular access options. Catheter-related bloodstream infection (CRBSI) is a major cause of hospitalization with increased mortality and cost. The purpose is to study the effect of the pathogen on the clinical course of the hemodialysis patients with CRBSI. Method Patients hospitalized in our department from 11/2021 to 12/2022 with established CRBSI were retrospectively studied. Their demographics, duration of hospitalization, microbiological data, central venous catheter management and hospital outcome were recorded. Results A total of 27 patients with median age (SD) 68,03 (16,93) years were treated, 12 (44.4%) were men. The following pathogens were isolated from the blood cultures: Staphylococcus aureus in 7 (25.9%) patients, coagulase-negative Staphylococcus in 10 (37%) patients, Gram-positive bacteria in 4 (14.8%) patients, Gram-negative bacteria in 3 (11.1%) patients, candida in one (3.7%) patient, while 2 (7.4%) patients had negative cultures. Mean (SD) duration of hospitalization was 16,85 (13,15) days for all patients. Patients in whom Staphylococcus aureus and Candida were isolated had longer hospital stay than other infections with a mean (SD) 29 (18) days and 41 days respectively (p = 0.014). Metastatic infections occurred in 4 (14,8%) patients, of whom 2 had endocarditis, one endocarditis and pulmonary abscess, and one endocarditis, lung abscess and brain abscess. All 4 patients isolated Staphylococcus aureus in blood culture out of a total of 7 (57,1%) patients with this pathogen (p = 0.02). 3 of 7 (42,8%) patients with Staphylococcus aureus, 1 of 10 (10%) with coagulase-negative Staphylococcus, and 1 of 3 (33,3%) with Gram-negative bacteria died (p = 0.385). In 26 of the 27 patients (96.3%) central venous catheter was removed. Conclusion The majority of patients in the present sample required central venous catheter removal. The type of pathogen seems to play an important role both in the duration of hospitalization and in the occurrence of metastatic infections.

Cross-sectional study of quality of life in relation with vascular access in hemodialysis patients

Introduction: Vascular access for hemodialysis (HD) is essential for the patient. Even though Arteriovenous fistula (AVF) is the preferred access, in certain age groups, the central venous catheter (CVC) may provide advantages. This study aims to investigate the quality of life related to vascular access. Methods: Cross-sectional study including patients from a hospital, a home HD unit and a satellite hemodialysis center. Clinical data was collected from the patients, who went through a quality-of-life questionnaire SF12 and a Vascular Access Questionnaire (VAQ). Results: 91 patients participated, mostly male (70%), with a mean age of 68.9 ± 16.2 years. AVF was the current vascular access in 60.4%, the rest used a CVC. Home HD was performed in 12.1% of patients and 76% started it via CVC. Regarding patients who have had both AVF and CVC, 58% prefer AVF and only 26.5% of current CVC carriers would have a new AVF, mostly due to fear of pain (52%). Most people (72.5%) reported having received sufficient information, with no differences between both accesses. The SF12 results showed no differences between patients with AVF or CVC. Regarding the VAQ, patients with AVF were more satisfied with the social aspect (p = 0.036) and complications (p = 0.006). Conclusion: Patients with AVF had better outcomes than those using CVC regarding complications and social aspects. These differences are not attributable to a worse overall quality of life status of CVC patients. Most patients with CVCs refuse to go through a new AVF for fear of puncture pain.

Abstract 667: Endothelial Glucocorticoid Receptor Deficiency Affects Arteriovenous Fistula Maturation

Objectives: Arteriovenous fistulae (AVF) are the optimal conduit for hemodialysis access in patients with end-stage chronic kidney disease (CKD); however, AVF have high rates of failure due to aggressive neointimal hyperplasia (NIH) caused by vascular inflammation and endothelial-to-mesenchymal transition (EndMT). Since the endothelial glucocorticoid receptor is a negative regulator of vascular inflammation, we hypothesized that inhibition of the endothelial glucocorticoid receptor would promote EndMT and accelerate NIH. Methods: Aortocaval AVF were created in GR fl/fl , Tie-1 Cre + (GR EC-KO ) mice and control mice GR fl/fl , Tie-1 Cre - ( GR fl/fl ). Three weeks prior to AVF, CKD was created via 5/6 nephrectomy (Nx); ultrasound was used to determine AVF diameter and patency at postoperative days 7, 14, and 21. AVF were harvested at days 3, 7 and 21 and examined with histology, immunofluorescence, and Western blot. Results: At postoperative day 21, AVF diameter was significantly decreased in GR EC-KO mice, whereas there was increased AVF wall thickness and accumulation of extracellular matrix (ECM) components fibronectin (p<0.005), collagen1 (p<0.005), collagen3 (p<0.005), as well as p-smad2 (p<0.001), compared to the control mice. Endothelial cells in the AVF of GR EC-KO mice had significantly increased immunoreactivity of the mesenchymal markers notch3 (p<0.0001), vimentin (p<0.0001) and FSP-1 (p<0.005) compared to control mice, consistent with increased EndMT. There was no difference between GR EC-KO and control mice treated with 5/6Nx regarding body weight or aortic diameter. Conclusion: Absence of the endothelial glucocorticoid receptor promotes EndMT and wall thickening during venous remodeling in the CKD environment. These data suggest that the endothelial glucocorticoid receptor serves as a physiologic regulator of venous remodeling during AVF maturation.

Effect of taurolidine–citrate–heparin lock solution on inflammatory response and hemodialysis adequacy in hemodialysis patients with tunneled catheters

Background Catheter-related bloodstream infections (CRBSIs) are a significant cause of morbidity and mortality in hemodialysis (HD) patients using dialysis catheters. Short-term and long-term catheters are still being used as a vascular access in HD patients in our country. The aim of this study was to assess the effect of TauroLock-HEP500 as a lock solution on the incidence of CRBSIs, performance of HD permanent catheters, and HD adequacy. Patients and methods This was a randomized controlled trial carried out on 60 patients at Al-Zaitoun Specialized Hospital and Al-Demerdash Hospital – Ain Shams University. The patients were divided into two groups: taurolock group (group 1), which included 30 patients who received TauroLock-HEP500 (taurolidine, 4% citrate and 500 IU/ml heparin are combined in this solution), and heparin group (group 2), which included 30 patients who received unfractionated heparin (heparin sodium 5000 IU/ml) as a permanent catheter lock solution. Patients were followed up for 1 month for monitoring HD adequacy and incidence of CRBSI. Result At the end of the study, C-reactive protein was significantly higher in heparin group than the taurolock group (P=0.01). Moreover, urea reduction ratio significantly increased within group 1 (taurolock) (P≤0.001) and significantly decreased in group 2 (heparin) (P=0.034). Moreover, urea reduction ratio was significantly higher in group 1(taurolock) compared with group 2 (heparin) at the end of the study (P≤0.001). Regarding blood flow rate (BFR), there was a significant increase of BFR within group 1 (taurolock) after 1 month compared with the baseline (P≤0.001), whereas there was no significant change in group 2 (heparin) (P=0.387). Moreover, at the end of the study, there was a significant increase of BFR in group 1 (taurolock) than in group 2 (heparin) (P=0.056). One case with CRBSIs was demonstrated in the taurolock group compared with five cases in the heparin group (P=0.19). Conclusion The use of taurolidine–citrate–heparin lock solution in HD patients with dialysis catheters may be associated with better HD adequacy, lower incidence of CRBSI) and lower inflammatory markers in comparison with the use of heparin.

Patency of tertiary vascular access in hemodialysis patients: case series

Background: Transposed brachio-basilic arteriovenous fistula (TBB-AVF) or arteriovenous graft (AVG) can be considered when primary and secondary vascular access options have been exhausted. Evidence that compared both procedures remains scarce. We aimed to report and describe the effectiveness of TBB-AVF and AVG as tertiary vascular access, reviewing literature about the advantages of each procedure. Case Presentation: We presented a series of end-stage renal disease (ESRD) patients needing tertiary vascular access to compare each procedure's effectiveness. Our study included 17 patients with ESRD and multiple vascular access failures who needed tertiary vascular access for hemodialysis between January 2019 and August 2022. Patency in 6 months and 1 year were compared between TBB-AVF and AVG using the Kaplan-Meier curve. The early failure rate was 14.4% for TBB-AVF and 87.5% for AVG. TBB-AVF had a better patency rate than AVG (p=0.005; log-rank). Cumulative patency rates in six months and one year were 91.7% and 85.7% for TBB-AVF compared to 87.5% and 16.7% for AVG, respectively. Conclusion: The creation of TBB-AVF should only be suggested if primary and secondary vascular access options have been exhausted. The TBB-AVF was more effective in functional patency than AVG as tertiary vascular access.

Staged autogenous to prosthetic hemodialysis access creation strategy to maximize forearm options

ObjectiveWhen an adequate cephalic vein is not available for fistula construction, surgeons often turn to basilic vein or prosthetic constructions. Single-stage forearm prosthetic hemodialysis accesses are associated with poor durability, and upper arm non-autogenous access options are often limited by axillary outflow failure, which inevitably drives transition to the contralateral arm or lower extremity. We hypothesized that initial creation of a modest flow proximal forearm arterial-venous anastomosis to dilate (“develop”) inflow and outflow vessels, followed by a planned second-stage procedure to create a cannulation zone with a prosthetic graft in the forearm, would result in reliable and durable hemodialysis access in patients with limited options. MethodsWe performed an institutional cohort study from 2017 to 2021 using a prospectively maintained database supplemented with adjudicated chart review. Patients without traditional autogenous hemodialysis access options in the forearm underwent an initial non-wrist arterial-venous anastomosis creation in the forearm as a first stage, followed by a second-stage interposition graft sewn to the existing inflow and venous outflow segments to create a useable cannulation zone in the forearm while leveraging vascular development. Outcomes included time from second-stage access creation to loss of primary and secondary patency, frequency of subsequent interventions, and perioperative complications. ResultsThe cohort included 23 patients; first-stage radial artery-based (74%) configurations were more common than brachial artery-based (26%). Mean age was 63 years (standard deviation, 14 years), and 65% were female. Median follow-up was 340 days (interquartile range [IQR], 169-701 days). Median time to cannulation from second-stage procedure was 28 days (IQR, 18-53 days). Primary, primary assisted, and secondary patency at 1 year was 16.7% (95% confidence interval [CI], 5.3%-45.8%), 34.6% (95% CI, 15.2%-66.2%), and 95.7% (95% CI, 81.3%-99.7%), respectively. Subsequent interventions occurred at a rate of 3.02 (IQR, 1.0-4.97) per person-year, with endovascular thrombectomy with or without angioplasty/stenting (70.9%) being the most common. There were no cases of steal syndrome. Infection occurred in two cases and were managed with antibiotics alone. ConclusionsFor patients without adequate distal autogenous access options, staged prosthetic graft placement in the forearm offers few short-term complications and excellent durability with active surveillance while strategically preserving the upper arm for future constructions.

How to choose the appropriate cannulation technique for vascular access in hemodialysis patients.

The cannulation technique is important for the survival of the arteriovenous access. Choosing the appropriate technique is a complex decision. Such choice must be customized to patients, considering their characteristics, the type of arteriovenous access and the experience of the hemodialysis team. We describe seven items that can help nurses to identify the appropriate cannulation technique: type of arteriovenous access; drainage vein; hygienic self-care profile; experience of the nursing staff in the cannulation technique and nurse-to-patient ratio; hemodialysis treatment method; patient's condition; and patient's decision. Such items can help nurses in decision-making on the "ideal" cannulation technique for each patient.

Multimodality imaging evaluation of arteriovenous fistulas and grafts: a clinical practice review.

Arteriovenous fistulas (AVFs) and grafts (AVGs) are the preferred forms of vascular access for hemodialysis in patients with severe renal dysfunction. Multimodality imaging plays an important role in the pre-procedural evaluation of these patients. Ultrasound is often used for pre-procedural vascular mapping in preparation for the creation of an AVF or AVG. Pre-procedural mapping includes a comprehensive evaluation of the arterial and venous vasculature including evaluation of vessel diameter, stenosis, course, presence of collateral veins, wall thickness and wall abnormalities. Computed tomography (CT), magnetic resonance imaging (MRI) or catheter angiography are used when sonography is not available or when further characterization of sonographic abnormalities is required. Following the procedure, routine surveillance imaging is not recommended. If there are any clinical concerns or if physical examination is inconclusive, further evaluation with ultrasound is warranted. Ultrasound allows for assessment of vascular access site maturation by evaluating the time-averaged blood flow and helping characterize the outflow vein in the case of an AVF. CT and MRI can play a complementary role to ultrasound. Vascular access site complications include non-maturation, aneurysm, pseudoaneurysm, thrombosis, stenosis, steal phenomena or occlusion typically of the outflow vein, infection, bleeding and rarely angiosarcoma. In this article, we review the role of multimodality imaging in the pre- and post-procedural evaluation of patients with AVF and AVG. Additionally, novel technologies of vascular access site creation using endovascular techniques and upcoming non-invasive imaging techniques for evaluation of AVFs and AVGs are discussed.

Liposuction to improve vascular access in hemodialysis patients with arteriovenous fistulas.

Arteriovenous fistulas (AVFs) are indispensable in the care of patients with end-stage renal disease requiring hemodialysis. Obesity is a common comorbidity in hemodialysis patients, often making AVF cannulation technically challenging. Liposuction can be performed for superficialization of the AVF without the need for an open superficialization procedure. The aim of the present study was to evaluate the outcomes of liposuction to improve AVF access for hemodialysis. We performed a retrospective medical record review of patients who had undergone liposuction over an AVF at our institution from January 2000 to September 2021. Data were collected on the demographics, medical comorbidities, AVF site and depth, AVF diameter and flow, operative details, surgical complications, and follow-up. A total of 19 patients had been referred by the hemodialysis clinic for liposuction. Their mean age was 55.5years, and their mean body mass index was 39.5kg/m2. Either liposuction alone or liposuction combined with minimal access direct lipectomy was performed to superficialize the AVF. All procedures were performed secondarily, after prior creation of the AVF. Of the 19 patients, 18 had had an upper AVF and 1 had had a lower extremity AVF graft. Of the 19 patients, 12 (63%) had proceeded to hemodialysis after one liposuction. The mean time to cannulation for 10 of these 12 patients was 52.1± 25.6days. Two of the 12 patients were excluded from the mean calculation to prevent skewing from their prolonged time to requiring dialysis initiation. Of the 19 patients, 2 had required additional liposuction sessions, and 1 had required AVF intervention after the first liposuction attempt before achieving successful cannulation. Four patients (21%) had had unsuccessful cannulation despite additional liposuction or AVF interventions owing to AVF stenosis or thrombosis. Overall, 15 of the 19 patients (79%) had successfully proceeded to dialysis in the same extremity. The mean access depth had decreased from 1.75cm before liposuction to 0.93cm after liposuction. The mean volume of fat removed was 92.3cm3. Of the 16 patients with prior dialysis catheters, 11 were eventually removed after surgery once the vascular site was accessible. The body mass index correlated positively with the interval to the first successful cannulation (r= 0.5881; P< .05). The surgical complications included two cases of cellulitis treated with oral antibiotics. The mean follow-up time was 38.3months. Our results have shown that liposuction can be performed safely in obese patients requiring hemodialysis and was successful in improved AVF access for 15 of the 19 patients (79%) in our cohort. Larger studies are needed to compare the outcomes of this technique with those of open superficialization.

Relationship between resistance index and recirculation rate in vascular access

BackgroundThe state of vascular access affects the efficiency of hemodialysis. Poor blood flow of vascular access causes recirculation, which reduces treatment efficiency. In the clinical setting, the resistance index (RI) is a commonly used parameter to evaluate the state of vascular access. However, there are few reports investigating the direct relationship between RI and the recirculation rate. In this study, the relationship between RI and the recirculation rate was investigated using computational fluid dynamics analysis.MethodsWe created a three-dimensional model that mimics vascular access in hemodialysis patients. Next, we input various blood flow waveforms (RI 0.00, 0.50, 0.60, 0.80, and 0.94) into the vascular model. Then, two needles were punctured into the blood vessel model. Blood was removed from the vessel by one needle at a rate of 200 ml/min and returned by the other needle at the same speed. The recirculation rate was calculated using the backflow from the blood return needle.ResultsThe recirculation rates for the blood flow waveforms of RI 0.00, 0.50, 0.60, 0.80, and 0.94 were 0.00%, 0.29%, 0.44%, 11.6%, and 28.1%, respectively. The recirculation rate was higher for blood flow with higher RI. In addition, more recirculation occurred during the diastolic phase, when blood flow was slow.ConclusionsWhen the minimum blood flow was slower than the hemodialysis blood removal speed, both backflow and the recirculation rate increased. Sufficient diastolic blood flow needs to be maintained to suppress recirculation.

A Cross-Sectional Epidemiological Study on the Status of Vascular Access in Hemodialysis Patients in Southwest China

A Cross-Sectional Epidemiological Study on the Status of Vascular Access in Hemodialysis Patients in Southwest China