Search Results (49)

Reliable vascular access remains a major clinical challenge for hemodialysis patients, as expanded polytetrafluoroethylene (PTFE) grafts exhibit poor patency and frequent complications driven by thrombosis and neointimal hyperplasia. Tissue-engineered vascular grafts offer a regenerative alternative but often lack the mechanical resilience required for high-flow arteriovenous (AV) environments. Here, we developed a reinforced, biofunctionalized coaxial electrospun graft comprising a poly(ε-caprolactone) mechanical core and a norbornene-functionalized poly(ethylene glycol) sheath incorporating pro-endothelialization cues. Circumferential PTFE rings were added to improve kink resistance. Grafts were implanted in a porcine AV configuration that recapitulates clinical hemodynamic conditions. Mechanical characterization included compliance, burst pressure, and kink resistance; host remodeling was assessed using histology, immunofluorescence, and multiphoton imaging at 4 weeks. Ring-reinforced electrospun grafts demonstrated a kink radius of 0.187 cm, compliance of 1.04 ± 0.29%/100 mmHg, and burst pressure of 1505 ± 565 mmHg, values all comparable to Gore-Tex PTFE and within industrial performance standards. In vivo, the electrospun grafts showed extensive host cell infiltration, collagen deposition, and formation of smooth muscle-like tissue, whereas PTFE controls remained largely acellular. Immunofluorescence confirmed intramural α-SMA⁺ and CD31⁺ cell populations, and multiphoton microscopy revealed significantly greater collagen and elastin content compared with PTFE (p < 0.05). Collectively, these findings demonstrate that the reinforced electrospun graft maintains mechanical integrity under physiological AV loading while supporting in situ endothelialization and extracellular matrix remodeling in a clinically relevant, large animal model. This work provides one of the first demonstrations of functional tissue regeneration within a fully synthetic, acellular scaffold in a porcine hemodialysis model and advances the translational development of durable, regenerative vascular access grafts that couple mechanical resilience with bioactive healing capacity. Full article

Background: Hemodialysis access dysfunction can lead to missed treatments and increased mortality. Traditional monitoring methods, such as physical examination and ultrasound, have limitations, emphasizing the need for a more efficient approach. This study investigates the use of digitized acoustic data to identify and monitor vascular access dysfunction. Methods: This prospective study involved patients undergoing hemodialysis with either arteriovenous fistulas (AVF) or arteriovenous grafts (AVG) between June 2023 and February 2025. All patients underwent vascular imaging (either angiography or ultrasound) to confirm the degree of stenosis. Acoustic data were recorded using a standardized procedure at various puncture sites. Pre- and post-angioplasty data were also collected to assess the effects of vascular intervention. The digitized acoustic data were analyzed for changes in relative loudness, peak-to-valley ratios, and frequency distribution. Results: A total of 157 patients with 236 audio recordings (mean age: 67 ± 11 years; 58% male) were included. Significant acoustic differences were found at the arterial puncture and anastomosis sites in AVF patients with dysfunction, particularly in venous site dysfunction, which exhibited a more pronounced reduction in sound volume and an increased peak-to-valley ratio. After angioplasty, acoustic changes were observed in both arterial and venous sites, with values moving toward normal levels. However, no significant acoustic changes were observed in AVG patients. Additionally, frequency distribution ratios showed minimal clinical relevance. Conclusions: Digitized acoustic data, particularly from the arterial puncture and anastomosis sites, can be an effective tool for detecting and monitoring hemodialysis access dysfunction. These findings suggest potential for acoustic analysis in clinical practice, especially when integrated with AI models for better diagnostics. Full article

Background/Objectives: Arteriovenous grafts (AVGs) are critical for hemodialysis access in patients with inadequate native vasculature. The Xeltis aXess graft, a novel bioresorbable vascular access conduit, promotes endogenous tissue restoration. While early outcomes have been promising, longer-term data remain limited. This report presents the longest reported, four-year follow-up on two of the first implanted aXess devices. Case Summaries: Case 1: A 64-year-old woman underwent aXess graft placement on 10 June 2021, between the right brachial artery and vein. She experienced graft thrombosis after 12 months and 18 months, both of which were successfully resolved with thrombectomy, in one instance in combination with drug-coated balloon (DCB) angioplasty. The graft remains functional. Case 2: A 76-year-old man received an aXess graft on 11 June 2021, in the left arm. After 6 months, he underwent balloon and DCB angioplasty for graft–vein (G–V) anastomosis stenosis. After 28 months, to resolve multiple pseudoaneurysms, followed by aneurysm resection and AVG reconstruction at month 29, a tunneled catheter was placed to perform dialysis sessions in the meantime. At month 44, graft-venous (G–V) angioplasty with DCB was performed to resolve G–V and axillary vein stenoses diagnosed at month 43. The graft remains in use. Results: Both patients retained functional dialysis access after four years, despite requiring multiple interventions for thrombosis, stenosis, and pseudoaneurysms. Conclusions: These cases demonstrate that the aXess graft can maintain functionality over four years with appropriate management, although close surveillance and reinterventions may be required. Full article

Background: While experimental models show that leptin and adiponectin have inverse effects on the cardiovascular system, it has been suggested that the leptin-to-adiponectin (L/A) ratio may be an important predictor of cardiovascular disease and death. Higher circulating leptin and adiponectin levels are observed in uremia due to decreased renal degradation and/or clearance and increased production. We sought to examine the association between the L/A ratio and mortality in a prospective hemodialysis cohort. Methods: Among a prospective cohort of 448 hemodialysis patients from the NIH “Malnutrition, Diet, and Racial Disparities in Chronic Kidney Disease (CKD) (MADRAD) study who underwent leptin and adiponectin measurements, we examined characteristics associated with high leptin and adiponectin (defined as the highest tertile) using logistic regression. We then examined the association of L/A ratio levels (categorized as tertiles) with all-cause mortality using Cox regression. Results: Multivariable logistic regression analyses showed female sex, diabetes, presence of an arteriovenous fistula/graft, and lower serum albumin, IL-6, and adiponectin were associated with high leptin, whereas female sex, longer vintage, Black race, higher IL-6, and lower leptin were associated with high adiponectin. When examining L/A ratios, the highest tertile was associated with lower mortality in case-mix Cox models (ref: lowest tertile): HR (95% CI) 0.14 (0.06–0.35). These associations were robust in analyses that additionally adjusted for laboratory covariates: (HR 95% CI) 0.18 (0.07–0.46). Conclusions: In a prospective cohort of hemodialysis patients, inflammation and malnutrition markers were associated with lower leptin and higher adiponectin levels. Additionally, high L/A ratio levels were associated with lower mortality. Further studies are needed to determine the mechanisms relating adipocytokines, inflammation and nutrition, and survival in this population. Full article

Bypass graft is widely used, especially in cardiovascular diseases, to detour clogged blood vessels, alleviating and correcting the manifestation of the symptoms of damaged blood vessels. Bypass grafting is also used in hemodialysis treatment, specifically an arteriovenous bypass graft, considering the repeated withdrawal of blood, for the dialysis machine to filter the blood and return it to the body to circulate. Nonetheless, bypass grafts are susceptible to failure due to the abnormal hemodynamic performance of the blood flowing to the graft, leading to complications such as thrombosis, intimal hyperplasia, and atherosclerosis. Multiple bypass graft designs are continuously developed to optimize the desirable hemodynamics of the blood, which is essential to avoid complications. This study examines helical arteriovenous bypass graft (AVG) hemodynamic performance using Computational Fluid Dynamics (CFD) simulations to identify enhanced blood flow characteristics. The analysis concentrated on area-weighted average wall shear stress (AWA-WSS), helicity, pressure drop, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) from twenty-seven graft models changing anastomosis angles, helical diameters, and helical pitches. Model 25-13-30 (25-degree anastomosis angle, 13 mm helical diameter, 30 mm helical pitch) demonstrated the most favorable overall hemodynamic performance based on the variables considered. The results indicate that integrating helical shape into bypass grafts improves hemodynamic performance, reduces intimal hyperplasia risk, and may prolong graft durability. These findings provide valuable insights and suggestions for enhancing AVG designs to support patient outcomes. Full article

Background: Despite efforts to rely on arteriovenous fistulas/grafts for maintenance hemodialysis, a significant number of patients still depend on tunnel hemodialysis catheters for treatment. This poses a risk factor for central line-associated bloodstream infection (CLABSI) and, subsequently, vascular access compromise. Method: We conducted a retrospective study in five dialysis centers to determine the potential factors resulting in vascular access loss, CLABSI incidence, and microbe distribution patterns in Saudi Arabia at centers under the Ministry of National Guard Health Affairs. Adults who regularly received hemodialysis and had positive blood cultures between January 2019 and December 2023 were the subjects of the study. Results: Our study identified the presence of tunnel infection (p < 0.001), the presence of a Gram-negative pathogen (p = 0.036), and a high body mass index (BMI > 30) (p = 0.04) as potential risk factors leading to the loss of tunnel central venous catheters. In contrast, there was a lower probability of central venous catheter loss due to Gram-positive pathogens (p = 0.01). The CLABSI rate was 1.55 per 100 patients per month over a five-year period. Patients with CVC required more hospital treatment and had a significantly higher rate of vascular access loss (p < 0.001). Both central and peripheral blood cultures had nearly identical microbe spectra. Methicillin-sensitive Staphylococcus aureus (MSSA), Methicillin-resistant Staphylococcus aureus (MRSA), and Staphylococcus epidermidis had the highest prevalence rates among Gram-positive organisms. Among the Gram-negative bacteria, Enterobacter cloacae was the most common, followed by Klebsiella pneumonia and Pseudomonas aeruginosa. Conclusions: Our findings indicate the need for rigorous measures and interventions to prevent Gram-negative infections and decrease the reliance on central venous catheters, to decrease infections in hemodialysis patients, and decrease morbidity and cost. Strict hand hygiene, patient education, and surveillance programs are recommended to monitor these patients. Full article

We report the case of a 44-year-old man with end-stage kidney disease (ESKD) who has been on chronic hemodialysis via a radio-cephalic arteriovenous fistula (RC-AVF) for one year. The patient arrived at the emergency department due to an inability to continue dialysis through the AVF. Clinical and ultrasound exams reveal an aneurysm in the cephalic vein, measuring 2.3 cm (cm) in diameter and 5 cm long, located in the middle third of the forearm, with intraluminal thrombosis. A surgical procedure is planned to exclude the aneurysmal segment and reconnect the vein, using a graft made from a bovine pericardium patch. Immediately after surgery, a thrill is detectable, and ultrasound shows a flow rate of 651 mL/min. On the second day, dialysis is performed through the distal cephalic vein segment under ultrasound guidance, avoiding the median forearm zone. At one month, the fistula remains functional, with no signs of thrombosis or stenosis. The bovine pericardium tubular graft has shown complete integration. This case supports the feasibility, safety, and potential advantages of using a tubularized bovine pericardial graft as an alternative conduit for RC-AVF reconstruction in select patients. However, further studies on larger cohorts and with extended follow-up are necessary to validate its reproducibility and long-term patency. Full article

Background: Vascular access (VA) is one of the most critical procedures during dialysis for patients with end-stage renal disease (ESRD), as it influences morbidity, mortality, and quality of life. Methods: This cross-sectional study analyzed the vascular access epidemiology of patients undergoing chronic HD in 15 nephrology centers across Greece from 2013 to 2019. Data on VA type, demographic characteristics, fatigue severity, and quality of life were gathered from a sample of 373 patients. Results: The prevailing result of this study is that arteriovenous fistula (AVF) was the commonly practiced VA, and its associated survival outcomes were better when compared to arteriovenous grafts (AVGs) and central venous catheters (CVCs). Patients with AVFs had significantly longer survival times (median 165 months) compared to non-fistula access. Furthermore, the degree of fatigue and quality of life were also dependent on the type of VA used, with patients on AVF having lower fatigue levels and better quality of life. Age, gender, and an early nephrologist referral were noted to affect the selection and the rate of maturation of VA. Despite AVF being the preferred VA, late referrals and high initial reliance on CVCs remain challenges. Conclusions: This study underscores the need for early nephrological intervention, surveillance programs, and patient education to optimize vascular access outcomes. Future research should focus on national strategies to reduce CVC-related complications and improve long-term HD care in Greece. Full article

This systematic review aimed to evaluate the potential of combining platelet-rich plasma (PRP) and polybutylene succinate (PBS) for the development of vascular grafts in patients undergoing chemotherapy. Relevant articles published in English or Italian were selected through a comprehensive search of MEDLINE (via PubMed) and the Cochrane Library. A total of ten screened articles and two additional relevant studies were included. The synthesis of results was conducted using digital tools, thoroughly reviewed by the authors. The quality assessment of the included studies revealed a medium-to-high risk of bias, with frequent limitations such as small sample sizes, experimental designs, and overall moderate to low methodological quality. Despite the heterogeneity of the findings, the available evidence suggests that radiocephalic graft placement and the use of PBS as a scaffold material, in combination with the growth factors contained in PRP, may improve clinical outcomes and reduce complications related to arteriovenous graft implantation. While promising, the current literature on this topic remains scarce and fragmented, underscoring the need for additional preclinical and clinical research. The proposed approach appears to hold potential for improving vascular access in oncology, but further in vivo validation is essential. This study received no external funding. Registration: PROSPERO ID CRD42025646724. Full article

Background: Socioeconomic status (SES) disparities impact health outcomes, but their effect on vascular access (VA) in hemodialysis patients in Korea remains underexplored. Methods: This study evaluated the association between SES and VA outcomes using National Health Insurance Service data from 2008 to 2019. Incident hemodialysis patients were categorized by insurance status into the health insurance group (HG) and medical aid group (MG). The primary endpoint was VA patency, and the secondary endpoint was all-cause mortality, adjusted for demographics, comorbidities, and lifestyle factors. Results: Among 86,036 patients, the MG (12.1%) was younger at VA creation (60.4 ± 13.5 vs. 63.1 ± 13.6 years, p < 0.001) and had higher rates of comorbidities (all p < 0.05 except cancer). Mortality rates per 100 person-years were higher in the MG (11.66 vs. 9.24 for AVF; 17.94 vs. 16.92 for AVG), as was the total procedure frequency (2.10 vs. 1.87, p < 0.001), despite similar percutaneous angioplasty counts (1.20 vs. 1.24, p = 0.314). Conclusions: Lower SES patients exhibited poorer VA patency and higher mortality rates despite equitable healthcare access and cost coverage in Korea. These findings suggest that non-medical factors, such as adherence to treatment and timely intervention, play a critical role in mitigating these disparities. Full article

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide. Key challenges such as atherosclerosis, in-stent restenosis, and maintaining arteriovenous access, pose urgent problems for effective treatments for both coronary artery disease and chronic kidney disease. The next generation of active implantables will offer innovative solutions and research opportunities to reduce the economic and human cost of disease. Current treatments rely on vascular stents or synthetic implantable grafts to treat vessels when they block such as through in-stent restenosis and haemodialysis graft failure. This is often driven by vascular cell overgrowth termed neointimal hyperplasia, often in response to inflammation and injury. The integration of biosensors into existing approved implants will bring a revolution in cardiovascular devices and into a promising new era. Biosensors that allow real-time vascular monitoring will provide early detection and warning of pathological cell growth. This will enable proactive wireless treatment outside of the traditional hospital settings. Ongoing research focuses on the development of self-reporting smart cardiovascular devices, which have shown promising results using a combination of virtual in silico modelling, bench testing, and preclinical in vivo testing. This innovative approach holds the key to a new generation of wireless data solutions and wireless powered implants to enhance patient outcomes and alleviate the burden on global healthcare budgets. Full article

This study illustrates the utility of a mixed-methods approach in assessing the value of an example novel technology—biosensor-integrated self-reporting arteriovenous grafts (smart AVGs). Currently in preclinical development, the device will detect arteriovenous graft stenosis (surveillance-only use case) and treat stenosis (interventional use case). The approach to value assessment adopted in this study was multifaceted, with one stage informing the next and comprised a stakeholder engagement with clinical experts to explore the device’s clinical value, a cost–utility analysis (CUA) from a US Medicare perspective to estimate pricing headroom, and an investment model estimating risk-adjusted net present value analysis (rNPVs) to determine commercial viability. The stakeholder engagement suggested that it would currently be difficult to establish the current value of the surveillance-only use case due to the lack of well-established interventions for preclinical stenosis. Based on this, the CUA focused on the interventional use case and estimated economically justifiable prices at assumed effectiveness levels. Using these prices, rNPVs were estimated over a range of scenarios. This value assessment informs early decision-making on health technology R&D by identifying the conditions (including clinical study success, potential market size and penetration, market access strategies, and assumptions associated with CUA) under which investment may be considered attractive. Full article

Chronic kidney disease (CKD) affects more than 10% of the world’s population. Hemodialysis, along with peritoneal dialysis and renal transplant, is one of the renal replacement therapies offered to patients with CKD/end-stage renal disease (ESRD). To proceed with hemodialysis, vascular access is required. The two means of long-term access are arteriovenous fistula (AVF) and arteriovenous graft (AVG). Multiple therapies have been created to help the long-term patency of AVFs. These therapies are needed as 40% of AVFs fail within the first year and additional intervention is required. Much of the existing research has focused on biomarkers, immune cells, hypoxia, and cell-based therapies. Regeneration therapy using mesenchymal stem cells seeks to investigate other ways that we can treat AVF failure. Mesenchymal stem cells are harvested as two main types, fetal and adult. Fetal cells are harvested at different times in fetal gestation and from multiple sources, placental blood, Whartons jelly, and amniotic stem cell fluid. Taken together, this review summarizes the different preclinical/clinical studies conducted using different types of MSCs towards vascular regenerative medicine and further highlights its potential to be a suitable alternative approach to enhance AVF patency. Full article

Objectives: The choice of vascular access continues to be a critical component in the management of hemodialysis patients. Despite the international consensus favoring arteriovenous (AV) fistulas, the use of central venous catheters (CVCs) remains prevalent, with substantial variations across countries and even among dialysis centers within the same region. This study examines the prevalence of CVC use among chronic hemodialysis (CHD) patients in Vienna, Austria, and explores inter-center differences. Methods: A cross-sectional analysis was conducted on patients receiving CVC-based CHD in Vienna as of March 2023. Patient demographics, comorbidities and their hemodialysis history were collected. Additionally, a subset of the population underwent vascular access (VA) mapping to assess eligibility for AV fistula (AVF) or AV graft (AVG) creation. Results: A total of 335 patients received CVC-based hemodialysis, equaling a CVC proportion of 42.5%. 191 (57.0%) patients on CVC-based CHD gave their consent to record their clinical data and vascular access history. Of the 191 included patients, 61 gave their consent to receive VA mapping. Of the 61 patients who received VA mapping, 60 (98.4%) were eligible for an upper extremity AVF or AVG. There was no significant difference regarding patient demographics, dialysis vintage, history of previous AVF or AVG or Charlson Comorbidity Index between the mapping and non-mapping group. The odds ratio of having a CVC in the absence of in-house vascular surgery was 3.41 (95% CI: 2.31–5.02, p-value < 0.001) compared to patients with in-house vascular surgery. Conclusions: The majority of patients that consented to ultrasound VA mapping fulfilled vascular requirements for AVF or AVG creation. Our study highlights the potential to decrease the prevalence of CVC-based CHD in Vienna that could translate to a reduction in CVC-associated complications. Full article

Background/Objectives: Arteriovenous (AV) graft is a procedure for hemodialysis performed in the arm. Optimizing AV graft design is vital to enhance haemodialytic efficiency in patients with kidney disease. Despite being a standard procedure, making it work optimally is still difficult due to various graft diameters and anastomosis configurations, which have limited studies. This research aims to find the ideal AV graft tube diameter on blood flow and pressure gradients and the ideal body site for AV graft implantation and to study their angles for dialysate flow. Methods: Nine models were designed in Autodesk Fusion 360 with 40°, 50°, and 60° angles each having 2 mm, 5.1 mm, and 14.5 mm diameters, all following specific equations on continuity, momentum (Navier-Stokes Equation)), and the Reynolds Stress Model (RSM). The CFD simulation of these models was performed in ANSYS Fluent with an established parameter of 0.3 m/s inlet velocity and stiff/no-slip graft and artery wall boundary condition. Results: As a result, the design with a diameter of 14.5 mm and a 40° angle was overall the most ideal in terms of minimal wall shear stress and turbulence. Conclusions: Thus the brachiocephalic area or the forearm is calculated to be the most optimal implantation site. Additionally, varying angles do affect dialysate flow, as smaller values cause less stress. Full article