Dialysis Grafts Research Articles

3:45 PM Abstract No. 18 Multi-institutional two-year outcomes in dialysis graft management: real-world evidence

3:45 PM Abstract No. 18 Multi-institutional two-year outcomes in dialysis graft management: real-world evidence

An Unusual Case of an Epidermoid Cyst Eroding into an Arteriovenous Graft Resulting in Graft Loss

Arteriovenous grafts (AVG) are unfortunately vulnerable to infection given their nature of being a foreign body that is routinely accessed in a patient population that typically has multiple comorbidities. Management of AVG infections can become more complex when a patient has exhausted all options of hemodialysis access and gets an infection involving the AVG or a chronic wound in closed proximity. Herein, we present a case of an epidermoid cyst that caused breakdown of a thigh PTFE dialysis graft, which became infected and encapsulated the femoral anastomosis.

Multi-institutional Two-Year Outcomes in Dialysis Graft Management: Real-World Evidence

There remains substantial debate around the most appropriate management algorithm for dialysis access grafts. The role of percutaneous transluminal angioplasty (PTA) and stent grafts (SGs) remains controversial, and downstream effects of various treatment modalities remain unclear. Furthermore, there is an absence of a proper financial analysis to calculate the overall cost of care for these patients. The purpose of this study was to determine the optimal algorithm for the management of dialysis patients with an upper arm dialysis graft.

A Prospective Randomized Study Comparing the Use of Paclitaxel-Coated PTA Balloon Catheters Versus Plain Balloon PTA Catheters to Treat Stenotic Segments at the Venous Anastomotic Site After Thrombectomy for Thrombosed Prosthetic Vascular Grafts for Dialysis

A Prospective Randomized Study Comparing the Use of Paclitaxel-Coated PTA Balloon Catheters Versus Plain Balloon PTA Catheters to Treat Stenotic Segments at the Venous Anastomotic Site After Thrombectomy for Thrombosed Prosthetic Vascular Grafts for Dialysis

Endovascular thrombectomy versus open surgical thrombectomy for thrombosed arteriovenous hemodialysis graft

Objective: The aim of this study was to investigate the procedure success rate, one-year primary patency rate, one-year secondary patency rate, and complications compared between endovascular therapy and open surgical thrombectomy for treatment of thrombosed arteriovenous hemodialysis graft.Methods: This retrospective chart review included patients with thrombosed arteriovenous hemodialysis graft who were treated at the Division of Vascular Surgery, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand during January 2012 to December 2016. Demographic, graft type, time before treatment, thrombus removal technique, additional technique, procedure success rate, operative, primary and secondary patency, follow-up time, and complication data were collected.Results: Seventy-four thrombosed dialysis grafts were included. Twenty-five and 49 grafts underwent endovascular therapy and open surgical thrombectomy, respectively. There was no significant difference in demographic data, graft type, or adjunct procedure between groups. The procedure success rate was 92% and 98% in the endovascular group and thrombectomy group, respectively (p=0.262). The one-year primary patency rate was 26% in the endovascular group, and 33% in the thrombectomy group (p=0.054). One-year secondary patency rate was 82.6% in the endovascular group, and 56.3% in the thrombectomy group (p=0.122).Conclusion: No significant differences were observed between groups for procedure success rate or 1-year primary patency rate; however, the one-year secondary patency rate in the endovascular group was significantly better than in the thrombectomy group. No difference in complications was observed between groups.

Computational study on the haemodynamic and mechanical performance of electrospun polyurethane dialysis grafts

Compliance mismatch between an arteriovenous dialysis graft (AVG) and the connected vein is believed to result in disturbed haemodynamics around the graft–vein anastomosis and increased mechanical loading of the vein. Both phenomena are associated with neointimal hyperplasia development, which is the main reason for AVG patency loss. In this study, we use a patient-specific fluid structure interaction AVG model to assess whether AVG haemodynamics and mechanical loading can be optimised by using novel electrospun polyurethane (ePU) grafts, since their compliance can be better tuned to match that of the native veins, compared to gold standard, expanded polytetrafluoroethylene (ePTFE) grafts. It was observed that the magnitude of flow disturbances in the vein and the size of anastomotic areas exposed to highly oscillatory shear (hbox {OSI} >0.25) and very high wall shear stress (>40 hbox { Pa}) were largest for the ePTFE graft. Median strain and von Mises stress in the vein were similar for both graft types, whereas highest stress and strain were observed in the anastomosis of the ePU graft. Since haemodynamics were most favourable for the ePU graft simulation, AVG longevity might be improved by the use of ePU grafts.

A randomized controlled trial of drug-coated balloon angioplasty in venous anastomotic stenosis of dialysis arteriovenous grafts

ObjectivePaclitaxel-coated balloons are used to reduce neointimal hyperplasia in native arteriovenous (AV) fistulas. However, no study specifically evaluated their effect on venous anastomotic stenosis of dialysis grafts. We aimed to compare the efficacy of angioplasty with drug-coated balloons (DCBs) and angioplasty with conventional balloons (CBs) for venous anastomotic stenosis in dysfunctional AV grafts. MethodsIn this investigator-initiated, single-center, single-blinded, prospective randomized controlled trial, we randomly assigned 44 patients who had venous anastomotic stenosis to undergo angioplasty with DCBs (n = 22) or CBs (n = 22) from July 2015 to August 2018. Access function was observed per the hemodialysis center's protocols; ancillary angiographic follow-up was performed every 2 months for 1 year after the interventions. The primary end point was target lesion primary patency at 6 months. Secondary outcomes included anatomic and clinical success after angioplasty, circuit primary patency at 6 months and 1 year, and target lesion primary patency at 1 year. ResultsAt 6 months, target lesion primary patency in the DCB group was significantly greater than that in the CB group (41% vs 9%; hazard ratio [HR], 0.393; 95% confidence interval [CI], 0.194-0.795; P = .006), as was the primary patency of the entire access circuit (36% vs 9%; HR, 0.436; 95% CI, 0.218-0.870; P = .013). At 1 year, the target lesion primary patency in the DCB group remained greater than that in the CB group (23% vs 9%; HR, 0.477; 95% CI, 0.243-0.933; P = .019) but not the primary patency of the access circuit (14% vs 9%; HR, 0.552; 95% CI, 0.288-1.059; P = .056). No difference in anatomic or clinical success was observed; no major complications were noted. ConclusionsAngioplasty with DCBs showed a modest improvement in primary patency of venous anastomotic stenosis and all dialysis AV grafts at 6 months. The short-term benefit was not durable to 1 year, and reinterventions were eventually needed.

Treatment of failing arterio-venous dialysis graft by angioplasty, stent, and stent graft: Two-years analysis of patency rates and cost-effectiveness.

The objective of this prospective randomized single-center study was to compare primary and secondary patency rates, number of percutaneous transluminal angioplasty (PTA) interventions and cost-effectiveness among PTA, deployment of a stent, or a stent graft in the treatment of failing arteriovenous dialysis grafts (AVG) due to restenosis in the venous anastomosis or the outflow vein. Altogether 60 patients with failing AVG and restenosis in the venous anastomosis or the outflow vein were randomly assigned to either PTA, placement of a stent (E-Luminexx®) or stent graft (Fluency Plus®). After the procedure, patients with stent or stent graft received dual antiplatelet therapy for the next three months. Follow-up angiography was scheduled at 3, 6, and 12 months unless requested earlier due to suspected stenosis or malfunction of the access. Subsequently, angiography was performed only if requested by the clinician. During a median follow-up of 22.4 (IQR=5.7) months patients with PTA, stent, or stent graft required 3.1±1.7, 2.5±1.7, or 1.7±2.1 (P=0.031) secondary PTA interventions. The primary patency rates were 0, 18 and 65% at 12 months and 0, 18 and 37% at 24 months in the PTA, stent, and stent graft group respectively (P<0.0001). The cost of the procedures in the first two years was €7,900±€3,300 in the PTA group, €8,500±€4,500 in the stent group, and €7,500±€6,200 in the stent graft group (P=0.45). We conclude that the treatment of failing dialysis vascular access by the deployment of a stent graft significantly improves its primary patency rates and decreases the number of secondary PTA interventions; however, the reduction in costs for maintaining AVG patency is not significant.

An immediate access dialysis graft designed to prevent needle-related complications: Results from the initial pre-clinical studies.

No technology has been specifically developed with the intent to reduce needle-related vascular access injuries; a significant source of complications and abandonment. We present the initial pre-clinical study results of a novel, self-sealing, immediate cannulation dialysis graft that aims to prevent needle-related complications; to promote safe, reliable needle access; to reduce catheter use; and could facilitate home hemodialyisis. The innovative graft design consists of two cannulation chambers with self-sealing properties and materials that prevent side and back wall needle puncture. Study and control grafts (expanded polytetrafluoroethylene) were implanted in one pig and 10 sheep in two studies over the course of 1 year. First cannulation occurred immediately post implant for all study grafts. Post-cannulation time to hemostasis, hematoma and seroma formation, infection, and patency were recorded. The two studies account for nearly 60 weeks (average 6.4 weeks/graft) of study graft follow-up. In the ovine study, average study graft time to hemostasis was 27.3 s (standard deviation = 26.3, range = 0-120), and the control averaged 177.2 s (standard deviation = 113.4, range = 60-600), p < 0.0001. Secondary patency was 75% and 67% for the study and control grafts, respectively. Neither study nor control groups experienced seroma, graft infections, or deaths. All novel grafts in the studies were implanted successfully and functioned as intended. There were no complications related to tunneling of the study graft and the chamber prevented back/side wall needle injury. This novel technology may help to mitigate these needle-related complications, while allowing for early/immediate cannulation which could also reduce catheter contact time.

HEMODYNAMIC INVESTIGATION OF SUBCLAVIAN-CORONARY STEAL SYNDROME IN DIALYSIS PATIENTS WITH CORONARY ARTERY OCCLUSION AND DIFFERENT STENOSIS PERCENTAGES IN SUBCLAVIAN ARTERY

Purpose: Diseases of the coronary arteries represent critical cardiovascular bleakness and mortality around the world. The main focus of this study is to simulate hemodialysis patients undergoing Coronary Artery Bypass Graft (CABG) surgery by the left internal mammary artery. The survey is to investigate whether subclavian-coronary steal syndrome will occur in patients with stenosis in their left subclavian. Methods: A three-dimensional model of Brachial—Radial—Ulnar tree arterial system and dialysis graft are constructed and then simulated by the implementation of fluid–structure interaction (FSI) and non-FSI models. After consent was obtained, data attributed to dialysis patients who had undergone coronary bypass surgery at the Tehran Heart Center (THD) was collected. Results: Stenosis in the subclavian artery causes the left internal mammary artery (LIMA) graft to lack flow that, in CABG cases, is supplying the heart muscle. With the increase of stenosis from zero to 54%, the flow results show a negative flow indicating reversed flow in the artery. Meanwhile, the comparison between flow quantity of a normal Left Anterior Descending (LAD) and LIMA in case of 38% stenosis in subclavian shows that the amount of flow reaching the heart is less than standard. The threshold stenosis in the subclavian artery for which subclavian-coronary steal phenomena occurs is simulated to be around 54%. Furthermore, investigation of the effect of flow quantity in cases of hemodialysis versus nonhemodialysis shows that the flow is lessened in case of hemodialysis. Conclusions: In hemodialysis patients with more than 38% stenosis in left subclavian, it is well advised that LIMA bypass graft is not the preferred graft choice, and at 54% of subclavian stenosis, the steal phenomenon occurs.

26 Far Infra Red Therapy May Improve Dialysis Graft Dysfunction and Catheter Induced Thrombus

26 Far Infra Red Therapy May Improve Dialysis Graft Dysfunction and Catheter Induced Thrombus

Comparison of ECMO Patients Bridged to LVAD vs Bridged to Transplantation

Purpose With the implementation of the new heart allocation system, the goal of our study was to compare the outcomes of patients supported with extracorporeal membrane oxygenation who were bridged to transplantation versus bridged to a left ventricular assist device prior to transplantation. Methods The UNOS database was queried for all adult patients (age >=18) who required support with ECMO at the time of listing or while on the waitlist for a heart from 2001-2018. Patients who successfully underwent orthotopic heart transplantation were stratified into those bridged immediately to transplantation from ECMO and those bridged to an LVAD prior to transplantation. Demographics, one year survival, postoperative stroke, postoperative renal failure requiring dialysis, episodes of rejection, and graft failure were compared. Results A total of 186 patients meeting criteria were identified. 117 patients were bridged from ECMO directly to transplantation, and 69 patients were successfully bridged from ECMO to either a Heartmate II or Heartware device prior to transplantation. Kaplan-Meier survival estimates and log-rank test found a statistically significant difference in one year survival between patients who were bridge from ECMO to transplantation compared to those who were bridged to an LVAD prior to subsequent transplantation (p=0.0004, Figure 1). Incidence of new postoperative renal failure requiring dialysis (20.4% vs 1.5%), stroke (10.4% vs 1.5%), and postoperative graft failure (14.0% vs 2.9%) was higher and episodes of rejection requiring treatment (12.6% vs 18.8%) were lower in the patients bridged directly from ECMO to transplantation compared to patients bridged to an LVAD prior to transplantation. Conclusion Our study suggests that bridging ECMO patients to an LVAD prior to transplantation will result in improved one year survival compared to patients bridged to immediate transplantation. With the new heart allocation system, continued evaluation of outcomes is required to inform management strategies.

03:18 PM Abstract No. 355 How does detapering of dialysis grafts affect access flow, and does it result in steal?

03:18 PM Abstract No. 355 How does detapering of dialysis grafts affect access flow, and does it result in steal?

Tapered arteriovenous grafts do not provide significant advantage over nontapered grafts in upper extremity dialysis access

ObjectiveAlthough tapered dialysis access grafts are often used in an effort to prevent ischemic steal, their efficacy is uncertain. Our goal was to use real-world data to assess the performance of these grafts with respect to primary patency and ischemic steal. MethodsThe Vascular Quality Initiative database was queried from 2010 to 2017 for all patients undergoing tapered dialysis grafts in the upper arm. Multivariable analysis was performed to analyze primary patency, ischemic steal, and reinterventions. ResultsWe identified 3608 patients who received dialysis access grafts, 1473 tapered grafts and 2135 nontapered grafts. The mean age was 64.8 years, and 43.4% of the patients were male. Tapered grafts were used more often in female patients (60.5% vs 54%), nonwhite patients (53.3% vs 47.7%), patients with no previous access (28% vs 26.3%), grafts with an antecubital brachial artery origin (50% vs 44.4%), and grafts with an antecubital cephalic vein target (7.4% vs 3.7%; P < .05). Three-month outcomes between tapered and nontapered grafts were similar for wound infection (1.4% vs 2%; P = .31), ischemic steal (4.1% vs 4.6%; P = .58), and arm swelling (3.5% vs 2.9%; P = .38). Multivariable analyses revealed that in comparison to nontapered grafts, tapered grafts did not affect primary patency rates (hazard ratio [HR], 1.17; 95% confidence interval [CI], 0.96-1.42; P = .11), ischemic steal (HR, 1.03; 95% CI, 0.64-1.65; P = .92), difference in endovascular reintervention (HR, 1.08; 95% CI, 0.74-1.16; P = .5), or operative reintervention (HR, 1.25; 95% CI, 0.86-1.82; P = .24). ConclusionsTapered grafts for upper extremity arteriovenous access do not affect primary patency, development of steal, or endovascular reintervention in comparison to nontapered grafts. Our findings do not support the routine use of these grafts in dialysis access to improve outcomes.

Gender Disparities in Vascular Access Surgical Outcomes in Elderly Hemodialysis Patients

Background: Despite national vascular access guidelines promoting the use of arteriovenous fistulas (AVF) over arteriovenous grafts (AVGs) for dialysis, AVF use is substantially lower in females. We assessed clinically relevant AVF and AVG surgical outcomes in elderly male and female patients initiating hemodialysis with a central venous catheter (CVC). Methods: Using the United States Renal Data System standard analytic files linked with Medicare claims, we assessed incident hemodialysis patients in the United States, 9,458 elderly patients (≥67 years; 4,927 males and 4,531 females) initiating hemodialysis from July 2010 to June 2011 with a catheter and had an AVF or AVG placed within 6 months. We evaluated vascular access placement, successful use for dialysis, assisted use (requiring an intervention before successful use), abandonment after successful use, and rate of interventions after successful use. Results: Females were less likely than males to receive an AVF (adjusted likelihood 0.57, 95% CI 0.52–0.63). Among patients receiving an AVF, females had higher adjusted likelihoods of unsuccessful AVF use (hazard ratio [HR] 1.46, 95% CI 1.36–1.56), assisted AVF use (OR 1.34, 95% CI 1.17–1.54), and AVF abandonment (HR 1.28, 95% CI 1.10–1.50), but similar relative rate of AVF interventions after successful use (relative risk [RR] 1.01, 95% CI 0.94–1.08). Among patients receiving an AVG, females had a lower likelihood of unsuccessful AVG use (HR 0.83, 95% CI 0.73–0.94), similar rates of assisted AVG use (OR 1.05, 95% CI 0.78–1.40) and AVG abandonment, and greater relative rate of interventions after successful AVG use (RR 1.16, 95% CI 1.01–1.33). Conclusions: While AVFs should be considered the preferred vascular access in most circumstances, clinical AVF surgical outcomes are uniformly worse in females. Clinicians should also consider AVGs as a viable alternative in elderly female patients initiating hemodialysis with a CVC to avoid extended CVC dependence.

HDA 3. A Prospective Randomized Study Comparing the Use of Paclitaxel-Coated Percutaneous Transluminal Angioplasty Balloon Catheters With Plain Balloon Angioplasty Catheters to Treat Stenotic Segments at the Venous Anastomotic Site After Thrombectomy for Thrombosed Prosthetic Vascular Grafts for Dialysis

HDA 3. A Prospective Randomized Study Comparing the Use of Paclitaxel-Coated Percutaneous Transluminal Angioplasty Balloon Catheters With Plain Balloon Angioplasty Catheters to Treat Stenotic Segments at the Venous Anastomotic Site After Thrombectomy for Thrombosed Prosthetic Vascular Grafts for Dialysis

Long-term results of thigh arteriovenous dialysis grafts.

A proportion of hemodialysis patients exhaust all options for arteriovenous access in upper extremities. Arteriovenous thigh grafts are a potential vascular access option in such patients. We performed a retrospective study of all thigh arteriovenous access grafts placed between 1995 and 2015. The clinical, demographic patient information and patency of each thigh graft was determined from the time of surgical creation placement until abandonment, transfer to other modality, or center or end of study, and the reason for access failure documented. In total, 44 patients received 49 thigh arteriovenous accesses. The average age was 60 years (13-79 years); Half (53%) of the patients (n = 24) were female and 61% of the patients (n = 30) of arteriovenous accesses were left-sided. The cumulative proportion surviving (primary patency rates) at 12, 24, and 28 months were 43% (standard error = 9%), 33% (standard error = 9%), and 13% (standard error = 9%), respectively. The cumulative proportion of surviving grafts at 12, 24, and 48 months were 61% (standard error = 8%), 58% (standard error = 9%), and 31% (standard error = 13%), respectively. In total, 37 revisions were performed in 22 patients to maintain patency or eradicate infection. Infection occurred in 20 patients (39%) of thigh grafts requiring 16 patients (80% of those affected) to be removed; 14 patients had grafts (33.3%) that served as the lone hemodialysis arteriovenous access during the patients' lifetime on dialysis. Arteriovenous thigh graft access is used infrequently, but they have an acceptable patency. Some accesses require revisions and they have a high infection rate. Despite this, an acceptable proportion of leg grafts provide durable access for the dialysis lifetime of the patient.

Future of Smart Cardiovascular Implants.

Cardiovascular disease remains the leading cause of death in Western society. Recent technological advances have opened the opportunity of developing new and innovative smart stent devices that have advanced electrical properties that can improve diagnosis and even treatment of previously intractable conditions, such as central line access failure, atherosclerosis and reporting on vascular grafts for renal dialysis. Here we review the latest advances in the field of cardiovascular medical implants, providing a broad overview of the application of their use in the context of cardiovascular disease rather than an in-depth analysis of the current state of the art. We cover their powering, communication and the challenges faced in their fabrication. We focus specifically on those devices required to maintain vascular access such as ones used to treat arterial disease, a major source of heart attacks and strokes. We look forward to advances in these technologies in the future and their implementation to improve the human condition.

Early cannulation grafts for haemodialysis: An updated systematic review.

Early cannulation grafts are specifically designed for dialysis, whereas standard expanded polytetrafluoroethylene grafts were not. There is developing collective experience and literature available to allow the assessment of outcomes of these early cannulation grafts. The aim of this review was to review the evidence for both short- and long-term outcomes of early cannulation grafts. Using standardized searches of electronic databases in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses, the primary outcomes for this study were primary and secondary patency rates for early cannulation grafts for dialysis at 12 months and beyond. Secondary outcomes were timing of first cannulation, rates of access thrombosis, steal syndrome, pseudo-aneurysm and infection. A total of 19 studies were identified and included. These were divided into different graft types. Flixene™, Avflo™, Acuseal™ and Vectra™ grafts all showed that early cannulation within 72 h is possible. Twelve-month pooled primary and secondary patency rates were 43.3% (95% confidence interval: 31.6-55.4) and 73.4% (95% confidence interval: 63-82.7) for the Flixene graft, 58.2% (95% confidence interval: 48-68.1) and 79.2% (95% confidence interval: 68-88.7) for the Avflo graft, 43.6% (95% confidence interval: 30.7-56.9) and 70.5% (95% confidence interval: 49.7-87.8) for the Acuseal graft and 63.7% (95% confidence interval: 53.4-73.4) and 85.8% (95% confidence interval: 82.9-88.4) for the Vectra graft. Data for outcome beyond 12 months were limited to the more recent studies. This review confirms that early cannulation is not detrimental on the early outcome of early cannulation graft patencies. It has also shown that both Vectra and Avflo grafts have adequate long-term patencies. The data do not allow specific graft recommendations, as comparative trials would be required.

A prospective randomized study of stent graft placement after balloon angioplasty versus balloon angioplasty alone for the treatment of hemodialysis patients with prosthetic graft outflow stenosis

BackgroundHemodialysis graft outflow stenosis is a significant complication occurring in hemodialysis patients with prosthetic grafts for vascular access. Balloon angioplasty remains the first-line endovascular treatment of this complication, although covered stent graft implantation after balloon angioplasty also appears to be an effective and promising treatment. The aim of this study was to evaluate the efficacy and durability of stent graft placement after balloon angioplasty in comparison to balloon angioplasty alone for the treatment of graft outflow stenosis in hemodialysis patients. MethodsWe conducted a prospective randomized study of 98 patients with clinically significant dialysis graft outflow stenosis treated in the vascular surgery section of a tertiary medical center. The patients were randomized into two groups; 49 patients were treated with stent graft placement after balloon angioplasty, and 49 patients were treated with balloon angioplasty alone. All patients underwent angiography of the graft site at 3 and 6 months after intervention, and restenosis rates were compared between the two groups. In addition, the duration of postintervention primary patency in the two groups was recorded and analyzed. ResultsThe postintervention restenosis rate of the stent graft placement group was superior to that seen in the balloon angioplasty alone group (9% vs 69% at 3 months [P < .0001] and 29% vs 72% at 6 months [P < .0001]). The mean postintervention primary patency duration was 380.22 ± 28.54 days for the stent graft placement group and 151.08 ± 16.79 days for the balloon angioplasty alone group (P < .0001). ConclusionsThe use of stent grafts in hemodialysis patients with graft outflow stenosis yielded superior results compared with the results seen in hemodialysis patients treated with balloon angioplasty alone. Patients treated with stent grafts after balloon angioplasty had a lower restenosis rate and a longer duration of postintervention primary patency. The placement of a stent graft after balloon angioplasty appears to be an optimal therapeutic approach for the treatment of hemodialysis patients with graft outflow stenosis.