Vascular Access In Hemodialysis Patients Research Articles

Vascular Access Perception and Quality of Life of Haemodialysis Patients.

Background: Patient quality of life is widely used as a non-clinical determinant of care. For patients undergoing hemodialysis, vascular access is vital to the delivery of hemodialysis and its function may affect not only the clinical outcome of treatment but also the overall quality of life of the patient, highlighting the need for increased efforts to improve the quality of hemodialysis vascular access care. The objective of this study was to evaluate the correlation between vascular access perception and quality of life in patients undergoing hemodialysis. Methods: A total of 202 patients with active hemodialysis vascular access were included in the study. Quality of life was assessed using the Kidney Disease Quality of Life Instrument (KDQOL™) questionnaire, while vascular access perception was evaluated using the Vascular Access Questionnaire (VAQ). Results: The study presented evidence on the influence of vascular access for hemodialysis patients on their quality of life. This impact is related to factors directly associated with vascular access, such as the type of access and the patient's subjective evaluation of the access. Conclusions: The perception of vascular access is one of the factors that determines the quality of life of hemodialysis patients. The quality of life of hemodialysis patients decreases as the number of vascular access-related problems increases.

Successful management of fatal cardiac tamponade resulting from intravascular intervention for central vein occlusion in hemodialysis patients: A case report.

This case report highlights the successful management of fatal cardiac tamponade caused by intravascular intervention for central vein occlusion in hemodialysis patients. Prompt diagnosis and treatment are essential for patient prognosis in such cases. We present a case involving a challenging surgical procedure to address multiple complications, emphasizing the importance of early detection and appropriate interventions. The patient, who had a history of long-term central venous catheter use for hemodialysis, was diagnosed with central vein stenosis in addition to superior vena cava occlusion, hemodialysis catheter rupture, hypertension, and end-stage renal disease. Urgent ultrasound examination during surgery revealed pericardial effusion, prompting immediate pericardial drainage for stabilization. To overcome the complex challenges, we successfully performed an innominate vein-right atrial appendage bypass to restore vascular access and salvage the patient's life. The timely use of echocardiography for diagnosis and pericardial drainage contributed to stabilizing the patient's vital signs, providing an opportunity for subsequent surgical intervention. The innominate vein-right atrial appendage bypass procedure successfully relieved central vein stenosis and saved the patient's life. Although this surgical technique is not widely documented in hemodialysis patients with central venous involvement, it show cases the potential benefits for clinicians managing vascular access in this patient population. This case report underscores the need for awareness among clinicians regarding the risk of cardiac tamponade associated with intravascular intervention for central vein stenosis in hemodialysis patients. Minimizing central venous catheterization and prioritizing autogenous arteriovenous fistulas are crucial principles in preparing vascular access for hemodialysis patients. Early detection, timely interventions, and consideration of alternative surgical techniques can improve outcomes and prevent life-threatening complications.

Cathepsin G promotes arteriovenous fistula maturation by positively regulating the MMP2/MMP9 pathway

Background Arteriovenous fistula (AVF) is currently the preferred vascular access for hemodialysis patients. However, the low maturation rate of AVF severely affects its use in patients. A more comprehensive understanding and study of the mechanisms of AVF maturation is urgently needed. Methods and results In this study, we downloaded the publicly available datasets (GSE119296 and GSE220796) from the Gene Expression Omnibus (GEO) and merged them for subsequent analysis. We screened 84 differentially expressed genes (DEGs) and performed the functional enrichment analysis. Next, we integrated the results obtained from the degree algorithm provided by the Cytohubba plug-in, Molecular complex detection (MCODE) plug-in, weighted gene correlation network analysis (WGCNA), and Least absolute shrinkage and selection operator (LASSO) logistic regression. This integration allowed us to identify CTSG as a hub gene associated with AVF maturation. Through the literature search and Pearson’s correlation analysis, the genes matrix metalloproteinase 2 (MMP2) and MMP9 were identified as potential downstream effectors of CTSG. We then collected three immature clinical AVF vein samples and three mature samples and validated the expression of CTSG using immunohistochemistry (IHC) and double-immunofluorescence staining. The IHC results demonstrated a significant decrease in CTSG expression levels in the immature AVF vein samples compared to the mature samples. The results of double-immunofluorescence staining revealed that CTSG was expressed in both the intima and media of AVF veins. Moreover, the expression of CTSG in vascular smooth muscle cells (VSMCs) was significantly higher in the mature samples compared to the immature samples. The results of Masson’s trichrome and collagen I IHC staining demonstrated a higher extent of collagen deposition in the media of immature AVF veins compared to the mature. By constructing an in vitro CTSG overexpression model in VSMCs, we found that CTSG upregulated the expression of MMP2 and MMP9 while downregulating the expression of collagen I and collagen III. Furthermore, CTSG was found to inhibit VSMC migration. Conclusions CTSG may promote AVF maturation by stimulating the secretion of MMP2 and MMP9 from VSMCs and reducing the extent of medial fibrosis in AVF veins by inhibiting the secretion of collagen I and collagen III.

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.

Detection of Abnormal Wall Shear Stress and Oscillatory Shear Index via Ultrasound Vector Flow Imaging as Possible Indicators for Arteriovenous Fistula Stenosis in Hemodialysis.

The arteriovenous fistula (AVF) is an essential vascular access for hemodialysis patients. AVF stenosis may occur at sites with abnormal wall shear stress (WSS) and oscillatory shear index (OSI), which are caused by the complex flow in the AVF. At present, an effective method for rapid determination of the WSS and OSI of the AVF is lacking. The objective of this study was to apply an ultrasound-based method for determination of the WSS and OSI to explore the risk sites of the AVF. In this study, the ultrasound vector flow imaging technique V Flow was applied to measure the WSS and OSI at four different regions of the AVF to detect and analyze the risk sites: (i) anastomosis region, (ii) curved region, (iii) proximal vein and (iv) distal vein. Twenty-one patients were included in this study. The relative residence time was calculated based on the measured WSS and OSI. The curved region had the lowest WSS; the anastomosis region had a significantly higher OSI (p < 0.05) compared with the venous regions, and the curved region had a significantly higher RRT (p < 0.05) compared with the proximal vein region. V Flow is a feasible tool for studying WSS variations in AVF. The possible risk site in the AVF may be located in the anastomosis and curved regions, where the latter could present a higher risk for AVF stenosis.

#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&amp;lt;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&amp;lt;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&amp;lt;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.

#3197 A NOVEL INVESTIGATION OF AVF WITH A SECOND HARMONIC GENERATION MICROSCOPY IN PATIENTS WITH END STAGE RENAL DISEASE

Abstract Background and Aims The population of patients with end-stage renal disease is rapidly growing and hemodialysis (HD) remains the most common treatment option. In clinical practice, the formation of arteriovenous fistulas (AVFs) is considered a priority in order to ensure optimal vascular access for HD patients. One of the complications in the formation of AVF is the hyperplasia of the neointimal layer of the vein, which leads to the failure of the fistula. The impact of the arrangement of collagen fibers in the veins of AVFs is little studied and opens wide opportunities for investigations. The structural tissue can be imaged with polarimetric nonlinear microscopy. Collagen fibers have a non-centrosymmetric structure, so they can be effectively imaged by second harmonic generation (SHG) microscopy [1]. The polarimetric nonlinear microscopy, exploiting the multidimentional tensor nature of light-matter interactions, is emerging as a valuable research tool in biomedical investigations and applications to digital pathology, and is only now becoming technically feasible for potential clinical translation [2,3]. This proposal represents a novel application of multimodal polarimetric nonlinear microscopy in histopathology, and biomedical imaging. The aim of this study is to determine the influence of the arrangement of collagen fibers in veins on the formation efficiency of AVFs by using the innovative method of nonlinear SHG microscopy. Method In this prospective study, we first used a novel SHG microscopy method to investigate AVFs venous intima hyperplasia. V. Cephalica segment is being obtained during arteriovenous fistula formation surgery from patients with end stage renal disease and after the removal of aneurysmatic or fibrotic AVF. Cross-sections of venous specimens are being fixed in 10% buffered formalin and stained with hematoxylin and eosin (H&amp;E). Further, sample investigation is being performed in Laser Research Centre, Vilnius University using a home-built multiphoton laser-scanning microscope. The investigation is being performed with the permission of Lithuanian Biomedical Research Ethics Committee. Results We determined the arrangement of collagen fibers in veins before AVF formation and after the removal of aneurysmatic AVFs. It was observed that tunica intima of V. Cephalica is dominated both by endothelial cells and connective tissue made up of high-density collagen fibers. Whereas tunica adventitia consists mainly of collagen fibers. Collagen in tunica intima and adventitia are found to be highly noncentrosymmetric. Thus a strong SHG signal, resulting in high-contrast structural visualization of the V. Cephalica segment is generated. Conclusion Our initial investigations of AVF show clearly visible collagen fibers. The future work will focus on the structural changes of collagen fibers in the vein intimal hyperplasia. Further investigations need to be done to create artificial intelligence-based identification of new predictive collagen markers.

#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.

Effect of proximal artery restriction on flow reduction and cardiac function in hemodialysis patients with high-flow arteriovenous fistulas

ObjectiveArteriovenous fistula is the preferred vascular access for hemodialysis patients. High-flow arteriovenous fistula may cause high-output heart failure. Various procedures are used to reduce high-flow arteriovenous fistula. This study aimed to assess the efficacy of proximal artery restriction combined with distal artery ligation on flow reduction for high-flow arteriovenous fistula and on cardiac function and echocardiographic changes in patients undergoing hemodialysis. MethodsA retrospective analysis was performed on data collected from the medical records of patients undergoing hemodialysis with heart failure and high-flow arteriovenous fistula between May 2018 and May 2021. Thirty-one patients were treated with proximal artery restriction (banding juxta-anastomosis of the proximal artery) combined with distal artery ligation (anastomosis distal artery ligation). Changes in the Acute Dialysis Quality Initiative Workgroup cardiac function class, blood pressure, and echocardiography before and 6 months after flow restriction were compared, and post-intervention primary patency was followed-up. ResultsThe technical success rate of the surgery was 100%, and no surgery-related adverse events occurred. Blood flow and blood flow/cardiac output decreased significantly after flow restriction. Blood flow decreased from 2047.21 ± 398.08 mL/min to 1001.36 ± 240.42 mL/min, and blood flow/cardiac output decreased from 40.18% ± 6.76% to 22.34% ± 7.21% (P < .001). Post-intervention primary patency of arteriovenous fistula at 6, 12, and 24 months was 96.8%, 93.5%, and 75.2%, respectively. The Acute Dialysis Quality Initiative Workgroup cardiac function class improved significantly after 6 months of flow restriction (P < .001). The systolic and diastolic left heart function improved, as evidenced by a significant decrease in left atrial volume index, left ventricular end-diastolic/end-systolic diameters, left ventricular end-diastolic volume, left ventricular mass index, cardiac output, and cardiac index and an increase in lateral peak velocity of longitudinal contraction, average septal-lateral s', and lateral early diastolic peak velocity after flow restriction (P < .05). Systolic pulmonary artery pressure decreased from 32.36 ± 8.56 mmHg to 27.57 ± 8.98 mmHg (P < .05), indicating an improvement in right heart function. ConclusionsProximal artery restriction combined with distal artery ligation effectively reduced the blood flow of high-flow arteriovenous fistula and improved cardiac function.

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.

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.

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

Oxidative stress: An essential factor in the process of arteriovenous fistula failure.

For more than half a century, arteriovenous fistula (AVFs) has been recognized as a lifeline for patients requiring hemodialysis (HD). With its higher long-term patency rate and lower probability of complications, AVF is strongly recommended by guidelines in different areas as the first choice for vascular access for HD patients, and its proportion of application is gradually increasing. Despite technological improvements and advances in the standards of postoperative care, many deficiencies are still encountered in the use of AVF related to its high incidence of failure due to unsuccessful maturation to adequately support HD and the development of neointimal hyperplasia (NIH), which narrows the AVF lumen. AVF failure is linked to the activation and migration of vascular cells and the remodeling of the extracellular matrix, where complex interactions between cytokines, adhesion molecules, and inflammatory mediators lead to poor adaptive remodeling. Oxidative stress also plays a vital role in AVF failure, and a growing amount of data suggest a link between AVF failure and oxidative stress. In this review, we summarize the present understanding of the pathophysiology of AVF failure. Furthermore, we focus on the relation between oxidative stress and AVF dysfunction. Finally, we discuss potential therapies for addressing AVF failure based on targeting oxidative stress.

Challenging, Safe, and Effective Use of External Iliac Vein for Insertion of Tunneled Cuffed Hemodialysis Catheters: A Single-Center Prospective Study.

Background Providing well-functioning vascular access is crucial for patients undergoing chronic hemodialysis. Peripheral arteriovenous fistulas and grafts are the preferred accesses in hemodialysis patients. Patients with bilateral obstruction of internal jugular veins and subclavian veins require a suitable vascular access. Thus, the insertion of iliac vein tunneled cuffed catheters (TCCs) by interventional nephrologists may be a good option for these patients. We aimed to evaluate the outcomes of iliac vein TCCs in patients lacking other vascular options. Methods 80 tunneled cuffed hemodialysis catheters were inserted through the iliac veins of 80 patients with an end-stage kidney disease. Catheter insertion was guided by Doppler ultrasonography followed by plain radiography to detect the catheter tip and exclude complications. Results The insertion success rate was 100%. 25 patients developed catheter-related infections. The mean survival time per catheter was 328 days. At the end of the study, 40 catheters were still functioning, 15 patients were shifted to continuous ambulatory peritoneal dialysis and 5 patients were referred to the interventional radiology department for insertion of transhepatic inferior vena cava tunneled catheters. Resistant catheter-related infection was the main cause of catheter removal in 11 patients (17.5%) in this study. Catheter malfunction was the second most common cause of catheter removal in 9 patients (11.25%). Conclusion This study concluded that iliac vein TCCs can provide suitable vascular access in hemodialysis patients with bilateral obstruction of internal jugular veins and subclavian veins.

Comparison between transposed arteriovenous fistulas and arteriovenous graft for the hemodialysis patients: A meta-analysis and systematic review.

It is challenging for a surgeon to determine the appropriate vascular access for hemodialysis patients whose cephalic vein is usually inaccessible. The purpose of the study is to compare the complications and patency rates between transposed arteriovenous fistulas (tAVF) and arteriovenous graft (AVG) for the hemodialysis patients. Studies were recruited from PubMed, Cochrane library, EMBASE, the web of science databases, and reviewing reference lists of related studies from the inception dates to September 2, 2021. Statistical analyses were conducted using the statistical tool Review Manager version5.3 (Cochrane Collaboration, London, UK). I2 > 50% was defined as a high degree of heterogeneity, and then a random-effects model was used. Otherwise, the fixed-effects model was used. Odds ratio with its 95% confidence interval (95% CI) was used. Thirty-three trials (26 retrospective studies, four randomized controlled trials, two prospective trials, and one controlled-comparative study) with 6430 enrolled participants were identified in our analysis. The results showed that tAVF was accompanied with lower thrombosis rate (103/1184 (8.69%) vs 257/1367 (18.80%); I2 = 45%; 95% CI, 0.34 (0.26, 0.45)) and infection rate (43/2031 (2.12%) vs 180/2147 (8.38%); I2 = 0%; 95% CI, 0.20 (0.14, 0.30)) than arteriovenous graft. The significantly better primary patency rates, secondary patency rates, and primary assisted patency rates during follow-up were found in tAVF. However, the failure rate and the prevalence of hematoma were significantly lower in AVG group. No evidence showed the rate of overall mortality, steal syndrome, and aneurysm reduced in tAVF. Our results showed that tAVF is a promising vascular access technique for hemodialysis patients whose cephalic vein is inaccessible. Our data showed that tAVF has less thrombosis, infection risk, and better patency rates when compared with AVG. However, more attentions need to be paid to transposed arteriovenous fistulas maturation and hematoma.

Metastatic infectious complications in tunneled dialysis catheter-associated infections: a single-center experience

Aim: Although the guidelines recommend arteriovenous fistula (AVF) primarily as vascular access in hemodialysis patients, tunneled catheter (TC) use is gradually increasing. TCs are associated with an increased risk of infection. TC infections can cause many metastatic infectious complications such as infective endocarditis (IE), spondylodiscitis (SpD), and paravertebral abscess. This study aimed to determine the frequency, risk factors, and prognosis of metastatic infectious complications in patients admitted to our hospital with TC infections.&#x0D; Material and Method: Patients with TCs hospitalized to the Nephrology unit of Ondokuz Mayıs University Hospital between January 1, 2015, and January 1, 2020, with catheter infection, were included in the study. Demographic, clinical, and microbiological information was obtained from the patients' medical records retrospectively. Metastatic infectious complications were defined as IE, SpD, paravertebral or epidural abscess, and septic embolisms in any focus. Binary logistic regression analyzes were used to identify risk factors for metastatic infectious complications.&#x0D; Results: One hundred and forty-eight catheter episodes were included in the study. Eighty-seven (58.8%) of the patients were women. Metastatic infectious complications developed in 22 (14.9%) of the patients. Of these, ten patients had IE, ten patients had SpD, and two patients had both IE and SpD. Coagulase-negative staphylococci was obtained as pathogenic microorganism in most cases (9/22, 49%). Patients with infectious complications had higher length of hospital stay [46.5 (10-171) vs 18 (6-92); p