Arteriovenous Hemodialysis Research Articles

Retarded hand growth due to a hemodialysis fistula in a young girl

Long-term presence of an arteriovenous hemodialysis fistula (AVF) may lead to alterations in hand perfusion. In the case reported here, a 14-year-old girl developed pain associated with hand ischemia 5 years after a successful kidney transplantation. At age 8 years, she required a period of hemodialysis using an autogenous left upper arm AVF. Compared to the healthy right hand, a smaller ischemic left hand was observed in the presence of a patent AVF. Access flow was 1400 ml/min. Seldinger angiography demonstrated a stenotic brachial artery, and duplex measurements indicated a reversed blood flow in the radial artery. AVF ligation abolished the ischemic symptoms. Distal hypotension due to an impaired arterial inflow combined with a low resistance elbow AVF may result in chronic hypoperfusion of acral portions of the extremity and growth retardation. Access ligation is advised in children with an optimal renal transplant function and a patent elbow AVF suffering from lowered distal tissue perfusion.

Declotting of Arteriovenous Hemodialysis Acssess: A Comparison of Percutaneous Mechanical Thrombectomy and Angioplasty versus Open Thrombectomy

Maintaining patency of arteriovenous hemodialysis access (AVHA) in more than 25,000 patients is very costly. This study was set to compare the length of stay (LOS), hospital charges, and secondary patency rates of percutaneous mechanical thrombectomy (PMTA) versus open thrombectomy (OT).

Determination of Cardiovascular Mechanics Evolution in the Presence of the Arteriovenous Fistula

Uremic patients are prone to heart damage as a consequence of arteriovenous fistula (AVF) presence and hemodialysis treatment. Arteriovenous fistula induces hand ischemic syndrome and cardiac work increase, thus determining cardiac insufficiency in the medium to long term. This work investigates the cardiovascular mechanics evolution induced by the fistula presence. Twenty patients were enrolled; blood pressure, heart rate (HR), cardiac dimensions, and fistula flow were measured at scheduled intervals. A mathematical model of the cardiocirculatory system was implemented to simulate cardiovascular evolution. Input parameters were heart and vessel features; output of the model were cardiac performances indicators, partly reproducing measurable data and partly quantifiable only by using the model. Input and output variability and their long-term variations were analyzed. Blood pressure and peripheral resistance were found to be higher in uremic than in healthy subjects. Fistula tailoring showed increased cardiac fiber contractility and decreased peripheral resistances. Moreover, between 10 days and 3 months, an increased blood flow at the vascular access determined an increment in fiber contractility. In the same period, the 85% of the patients showed an increase in cardiac fiber stiffness. Similar but less pronounced trends were observed between 3 months and 1 year. The developed model reproduces the cardiovascular system in physiologic and pathologic conditions and allows description of the cardiovascular evolution for a uremic patient.

Fistula Salvage by Endovascular Therapy

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

Effect of Route of EPO Administration on Hemodialysis Arteriovenous Vascular Access Failure: A Randomized Controlled Trial

Vascular access failure is a major cause of morbidity and hospitalization in hemodialysis populations worldwide. Erythropoietin (EPO) potentially can contribute to vascular access stenosis and occlusion by promoting intimal hyperplasia and thrombosis. Intravenous administration of EPO results in a severe, but transient, increase in drug concentration within the vascular access, whereas subcutaneous administration leads to a mild, but sustained, increase in the systemic circulation. The effect of route of administration of EPO on vascular access outcomes is uncertain. Randomized controlled trial. 78 Korean hemodialysis patients were randomly assigned to receive either intravenous (n = 40) or subcutaneous (n = 38) EPO. EPO was administered during dialysis, and the dose was titrated to maintain hemoglobin levels between 9 to 12 g/dL. All patients received EPO 2 or 3 times/wk. Study duration was 4 to 77 months. The primary end point was time to vascular access failure. Analysis was performed using Cox regression analysis. The incidence of access failure was 4.7%/patient-year in the intravenous-therapy group and 12.0%/patient-year in the subcutaneous-therapy group, with an unadjusted hazard ratio of 3.24 (95% confidence interval, 1.31 to 8.00; P = 0.01). After adjustment for dialysis access type, vascular access age, previous intervention, serum phosphorus level, and diabetes mellitus, subcutaneous EPO administration was independently associated with increased vascular access failure (hazard ratio, 3.56; 95% confidence interval, 1.20 to 10.58; P = 0.02). There were no significant differences in either hemoglobin concentration or EPO dosage between the 2 groups during the study period. Relatively small sample size and lack of complete symmetry between the 2 groups with respect to some baseline characteristics. This study suggests that the risk of vascular access failure may be greater with subcutaneous compared with intravenous administration of EPO in hemodialysis patients.

Amplatzer Vascular Plug for Arteriovenous Hemodialysis Access Occlusion: Initial Experience

The Amplatzer Vascular Plug (AVP; AGA Medical, Golden Valley, MN) is a recently developed self-expanding metallic device indicated for peripheral vascular embolizations. Herein, we describe use of this device in the treatment of vascular complications related to arteriovenous hemodialysis fistulas and grafts. This HIPAA compliant retrospective study was approved by the institutional review board with informed consent waived. Six patients with problematic arteriovenous access underwent access occlusion using the AVP. Procedure indications included vascular steal syndrome in five patients, and enlarging vascular aneurysms in one patient. Contraindications for surgical correction were determined by the referring surgeon. AVP embolizations were performed using devices oversized by 50% introduced through vascular sheaths positioned within vein segments just beyond the arteriovenous anastomoses. Noninvasive evaluation of the involved extremity was performed pre- and post-embolization in addition to clinical follow-up examinations. Measured outcomes included success of angiographic occlusion, improvement in distal arterial flow, AVP number, AVP diameter, time to access occlusion, and clinical symptomatic improvement. Technical success was 100%, with complete arteriovenous access occlusion accomplished in all cases, with an average of 1.5 AVPs used per patient. Mean time to access occlusion was 19.3 minutes. Angiographic improvement in distal arterial flow was immediately evident and resolution of clinical symptoms occurred in all patients, with mean long-term follow-up of 16 months. No procedure-related complications were encountered. The Amplatzer Vascular Plug provides a minimally invasive and efficacious method for embolization of problematic arteriovenous hemodialysis access.

Distal Digital Embolization from a Thrombosed Aneurysmal Hemodialysis Arteriovenous Fistula: The Benefit of a Hybrid Approach

Aneurysmal degeneration of a hemodialysis arteriovenous fistula (AVF) is common; however, distal digital embolization from an AVF is extremely rare. Even though the ultimate fate of all arteriovenous hemodialysis access is thrombosis with minimal consequences, dislodgement of thrombus at the proximal anastomosis could lead to ischemia of the distal arterial circulation. We here present a case of a renal transplant patient with a thrombosed aneurysmal AVF who presented with acute digital ischemia successfully treated with combination catheter-directed thrombolysis and open repair. No similar report was found describing this entity treated with this approach.

Endovascular Interventions of Juxtaanastomotic Stenoses and Thromboses of Hemodialysis Arteriovenous Fistulas

To assess the primary and secondary patency rates for juxtaanastomotic stenoses, with or without superimposed thromboses, of arteriovenous hemodialysis fistulas treated with angioplasty and to compare it with National Kidney Foundation Dialysis Outcomes Quality Initiative treatment guidelines for stenosed and occluded arteriovenous fistulas (50% primary patency rate at 12 months). This study was a retrospective analysis, covering a period of 5(1/2) years. Forty-three hemodialysis patients were referred due to secondary fistula dysfunction, and angiography was diagnostic of a juxtaanastomotic lesion. Interventions consisted of standard angioplasty techniques along with thrombolysis and/or thrombectomy and intravascular stent placement as needed. Follow-up was performed at the attending dialysis center, and repeat angiography was performed as clinically required. Immediate postprocedural angiography demonstrated an angiographic success rate of 98%. Clinical success, with at least one session of normal dialysis, occurred in 95% of interventions. Primary patency rates at 12 months for the stenosed and stenosed/thrombosed fistulas were 56% and 64%, respectively. Secondary patency rates at 12 months were 64% and 63%, respectively. Half of the stenosed fistulas were patent at 1.5 years, 28% were patent at 4 years, and 13% remained patent at 6 years. No major complications were documented. Four minor complications, which did not require therapy, were noted. The results achieved are comparable to those reported for interventions at nonjuxtaanastomotic sites and exceed those quoted by the National Kidney Foundation Dialysis Outcomes Quality Initiative guidelines. Angioplastic interventions in a juxtaanastomatic area of arteriovenous fistulas are safe, promote prolonged patency, and postpone the need for surgical intervention or creation of a new fistula.

The Society for Vascular Surgery: Clinical practice guidelines for the surgical placement and maintenance of arteriovenous hemodialysis access

Recognizing the impact of the decision making by the dialysis access surgeon on the successful placement of autogenous arteriovenous hemodialysis access, the Society for Vascular Surgery assembled a multispecialty panel to develop practice guidelines in arteriovenous access placement and maintenance with the aim of maximizing the percentage and functionality of autogenous arteriovenous accesses that are placed. The Society commissioned the Knowledge and Encounter Research Unit of the Mayo Clinic College of Medicine, Rochester, Minnesota, to systematically review the available evidence in three main areas provided by the panel: timing of referral to access surgeons, type of access placed, and effectiveness of surveillance. The panel then formulated practice guidelines in seven areas: timing of referral to the access surgeon, operative strategies to maximize the placement of autogenous arteriovenous accesses, first choice for the autogenous access, choice of arteriovenous access when a patient is not a suitable candidate for a forearm autogenous access, the role of monitoring and surveillance in arteriovenous access management, conversion of a prosthetic arteriovenous access to a secondary autogenous arteriovenous access, and management of the nonfunctional or failed arteriovenous access. For each of the guidelines, the panel stated the recommendation or suggestion, discussed the evidence or opinion upon which the recommendation or suggestion was made, detailed the values and preferences that influenced the group's decision in formulating the relevant guideline, and discussed technical remarks related to the particular guideline. In addition, detailed information is provided on various configurations of autogenous and prosthetic accesses and technical tips related to their placement.

Complications of arteriovenous hemodialysis access: Recognition and management

English language citations reporting complications of arteriovenous access for hemodialysis are critically reviewed and discussed. Venous hypertension, arterial steal syndrome, and high-output cardiac failure occur as a result of hemodynamic alterations potentiated by access flow. Uremic and diabetic neuropathies are common but may obfuscate recognition of potentially correctable problems such as compression or ischemic neuropathy. Mechanical complications include pseudoaneurysm, which may develop from a puncture hematoma, degeneration of the wall, or infection. Dysfunctional hemostasis, hemorrhage, noninfectious fluid collections, and access-related infections are, in part, manifestations of the adverse effects of uremia on the function of circulating hematologic elements. Impaired erythropoiesis is successfully managed with hormonal stimulation; perhaps, similar therapies can be devised to reverse platelet and leukocyte dysfunction and reduce bleeding and infectious complications.

Surveillance of arteriovenous hemodialysis access: A systematic review and meta-analysis

Hemodialysis centers regularly survey arteriovenous (AV) accesses for signs of dysfunction. In this review, we synthesize the available evidence to determine to what extent proactive vascular access monitoring affects the incidence of AV access thrombosis and abandonment compared with clinical monitoring. We searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science, and SCOPUS) and sought references from experts, bibliographies of included trials, and articles that cited included studies. Two reviewers independently assessed trial quality and extracted data. We used random effects meta-analysis to estimate the pooled relative risk (RR) and 95% confidence interval (CI) across studies and conducted subgroup analyses to explain heterogeneity. The I(2) statistic was used to assess heterogeneity of treatment effect among trials. Nine studies (1363 patients) compared a strategy of surveillance vs clinical monitoring. A vascular intervention to maintain or restore patency was provided to both groups if needed. Surveillance followed by intervention led to a nonsignificant reduction of the risk of access thrombosis (RR, 0.82; 95% CI, 0.58-1.16; I(2) = 37%) and access abandonment (RR, 0.80; 95% CI, 0.51-1.25; I(2) = 60%). Three studies (207 patients) compared the effect of vascular interventions vs observation in patients with abnormal surveillance result. Vascular interventions after an abnormal AV access surveillance led to a significant reduction of the risk of access thrombosis (RR, 0.53; 95% CI, 0.36-0.76) and a nonsignificant reduction of the risk of access abandonment (RR, 0.76; 95% CI, 0.43-1.37). Very low quality evidence yielding imprecise results suggests a potentially beneficial effect of AV access surveillance followed by interventions to restore patency. This inference, however, is weak and will require randomized trials of AV access surveillance vs clinical monitoring for rejection or confirmation.

Methodology for clinical practice guidelines for the management of arteriovenous access

The Society for Vascular Surgery considers the placement and maintenance of arteriovenous hemodialysis access to be an important component of any vascular surgery practice. Therefore, the Society has long been involved in setting the standards for the management of arteriovenous access. Formulating clinical recommendations in this area is the latest effort by the Society to improve the management of arteriovenous access on a national level. To provide an unbiased study of the evidence and to help in formulating the recommendations, the Society used the Knowledge and Encounter Research (KER) Unit of the Mayo Clinic College of Medicine, Rochester, Minn, to review the available evidence and advise a multidisciplinary group of access surgeons and nephrologists in formulating the clinical recommendations. To review the evidence, randomized and observational study designs were both considered. Whenever possible, systematic reviews and meta-analyses of the literature were used because, compared with individual studies, they generate more precise estimates of treatment effects and their results are applicable to a wider range of patients. On behalf of the Society, the group issued its recommendations following the Grading of Recommendations Assessment, Development and Evaluation (GRADE) format; this format disentangles the strength of recommendations from the quality of the evidence and encourages statements about the underlying values and preferences relevant to the particular recommendation. The recommendations are classified as strong (denoted by the phrase "we recommend") or weak (denoted by the phrase "we suggest"); and the quality of evidence is classified as high, moderate, low, or very low. These recommendations are not meant to supersede clinical judgment; rather, they should be used as a guide for the practicing surgeon and nephrologist as the decision is being made for the placement and subsequent procedures and management of arteriovenous hemodialysis access are being considered.

Arteriovenous hemodialysis access: The Society for Vascular Surgery practice guidelines

Arteriovenous hemodialysis access: The Society for Vascular Surgery practice guidelines

Unilateral hemothorax in a 46 year old South Indian male due to a giant arteriovenous hemodialysis fistula: a case report

In a patient undergoing regular hemodialysis through an arteriovenous fistula access, pleural effusion is a known long term complication. However, a unilateral hemothorax is relatively uncommon. Here we report a 46 year old male, end-stage renal disease patient, on maintenance hemodialysis, who presented with a giant brachiocephalic AV fistula in his left arm and progressive breathlessness. Radiological imaging revealed a left sided pleural effusion. Ultrasound guided aspiration revealed a hemorrhagic pleural fluid. A Doppler study of the fistula revealed a high velocity blood flow through the fistula, thereby establishing the cause of the unilateral hemothorax. Ligation of the fistula resulted in complete resolution of the hemothorax. The other possible causes for hemothorax in a dialysis patient are also discussed in this case report.

A Novel Technique for Loading of Paclitaxel-PLGA Nanoparticles onto ePTFE Vascular Grafts

The major cause of hemodialysis vascular access dysfunction (HVAD) is the occurrence of stenosis followed by thrombosis at venous anastomosis sites due to the aggressive development of venous neointimal hyperplasia. Local delivery of antiproliferative drugs may be effective in inhibiting hyperplasia without causing systemic side effects. We have previously demonstrated that paclitaxel-coated expanded poly(tetrafluoroethylene) (ePTFE) grafts, by a dipping method, could prevent neointimal hyperplasia and stenosis of arteriovenous (AV) hemodialysis grafts, especially at the graft-venous anastomoses; however, large quntities of initial burst release have remained a problem. To achieve controlled drug release, paclitaxel (Ptx)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Ptx-PLGA-NPs) were prepared by the emulsion-solvent evaporation method and then transferred to the luminal surface and inner part of ePTFE vascular grafts through our micro tube pumping and spin penetration techniques. Scanning electron microscope (SEM) images of various stages of Ptx-PLGA-NPs unequivocally showed that micro tube pumping followed by spin penetration effectively transferred Ptx-PLGA-NPs to the inner part, as well as the luminal surface, of an ePTFE graft. In addition, the in vitro release profiles of paclitaxel demonstrated that this new system achieved controlled drug delivery with a reduced initial burst release. These results suggest that loading of Ptx-PLGA-NPs to the luminal surface and the inner part of an ePTFE graft is a promising strategy to ultimately inhibit the development of venous neointimal hyperplasia.

Fetuin-A Expression in Early Venous Stenosis Formation in a Porcine Model of Hemodialysis Graft Failure

Because fetuin-A is a cytokine with multifunctional effects on vascular smooth muscle cells and fibroblasts, the authors examined the course of its expression in early venous stenosis formation in a porcine model of chronic renal insufficiency with polytetrafluoroethylene (PTFE) arteriovenous (AV) hemodialysis grafts. Pigs had chronic renal insufficiency created by complete embolization of the left kidney and partial embolization of the right kidney. Twenty-eight days later, PTFE AV grafts were placed from the carotid artery to the ipsilateral jugular vein, and the animals were euthanized 3 days (n = 4), 7 days (n = 4), or 14 days (n = 4) later. Expression of fetuin-A was determined by Western blot analysis of the venous stenosis, control veins, and plasma. Immunohistochemical analysis of the venous stenosis and control vein was performed. Blood urea nitrogen (BUN) and creatinine were measured before embolization and at the time of graft placement. The mean BUN and creatinine levels at graft placement were significantly higher than before embolization (P < .05). Severe venous neointimal hyperplasia occurred by day 14 and was characterized by primarily alpha-smooth muscle actin-positive cells. By day 14, fetuin-A levels had increased significantly (P < .05) at the venous stenosis compared with control veins and in the serum compared with measurements before embolization. Significantly increased expression of fetuin-A was observed in early venous stenosis by day 14 and in serum compared with baseline measurements. Understanding the role of fetuin-A in venous neointimal hyperplasia could help in improving outcomes in patients undergoing hemodialysis.

Renal replacement therapy in support of combat operations

Renal replacement therapy has been used by the U.S. Army at the combat support hospital echelon of care since the Korean conflict. Although there has been a general decline in the incidence of wartime acute kidney injury, the mortality associated with acute kidney injury and the use of renal replacement therapy remain unchanged, in the range of 60% to 80%. The U.S. Army official doctrine is that field dialysis is provided through a specialized Hospital Augmentation Team; however, this team has not been deployed to either Iraq or Afghanistan as a result of the ability to rapidly evacuate most cases requiring renal replacement therapy. The history of wartime renal replacement therapy is reviewed along with the general epidemiology of battlefield acute kidney injury and renal replacement therapy. Recent literature documents cases of renal replacement therapy performed in and out of theater in support of the current operations. In-theater renal replacement therapy has been provided through a variety of modalities, including conventional hemodialysis, peritoneal dialysis, and both continuous venovenous and continuous arteriovenous hemodialysis. Out of theater, casualties have received both intermittent and continuous hemodialysis at Landstuhl Regional Medical Center and Walter Reed Army Medical Center, whereas patients sustaining burns have undergone aggressive continuous venovenous hemofiltration or hemodiafiltration at Brooke Army Medical Center. Acute kidney injury requiring renal replacement therapy in wartime casualties is an uncommon occurrence but one with extremely high mortality. Future doctrine should be prepared for contingencies in which the incidence may be increased as a result of mass crush injury casualties or prolonged evacuation times.

The effect of implementation of an optimized care protocol on the outcome of arteriovenous hemodialysis access surgery

The long-term patency of arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) suffers from a high incidence of primary failure due to early thrombosis, myointimal hyperplasia at the venous access site, or failure to mature. A multidisciplinary meeting in vascular access surgery was initiated to optimize the timing, indication, type of intervention, and the logistics of AVFs/AVGs during the preoperative and postoperative period. This study evaluated the influence of the new optimized care protocol on the incidence of revisions (surgical and endovascular) and patency rates. This protocol for vascular access surgery of AVFs/AVGs for hemodialysis was introduced in January 2004. It was initiated with the presence of the vascular surgeons, nephrologists, interventional radiologists, dialysis nurses, and the ultrasound technicians. Every patient who needed an AVF/AVG because of long-term treatment of chronic renal failure or awaiting kidney transplantation, or who needed a revision of an AVF/AVG, was discussed. Two groups were compared. Group I patients were treated with an AVF/AVG before the introduction of the new protocol (2001 and 2002). Group II patients were treated with an AVF/AVG after the introduction of the new optimized care protocol (2004 and 2005). Both groups were followed up after 12 months. During the study period, 146 AVFs/AVGs were attempted, and 111 postoperative revisions were performed to restore primary and secondary patency: 63 in group I (60 surgical, 3 radiology) and 48 in group II (23 surgical, 25 radiology). Significantly more segmental access replacements (P < 0.027) occurred in group I than in group II. Significantly fewer surgical revisions (P < 0.019) and more endovascular balloon angioplasties (P < 0.001) occurred in group II. Significantly higher cumulative primary and secondary patency rates of all AVFs/AVGs (P < 0.001), radial-cephalic direct wrist AVFs (P < 0.001), and brachial-cephalic forearm looped transposition AVGs (P < 0.001) were achieved in group II after follow-up. The new protocol outlined in a bimonthly multidisciplinary meeting for vascular access surgery of AVFs/AVGs for hemodialysis resulted in more effective logistics according to preoperative diagnostics and operation. More importantly, a significant increase in endovascular balloon angioplasties and a significant decrease in surgical revisions was observed, resulting in less patient morbidity. Also, higher primary and secondary patency was achieved after the introduction of the new optimized care protocol.

Reduced Burst Release from ePTFE Grafts: A New Coating Method for Controlled Drug Release

Hemodialysis graft coated with paclitaxel prevents stenosis; however, large initial burst release of paclitaxel causes many negative effects such as drug toxicity and inefficient drug loss. Therefore we developed and tested a novel coating method, double dipping, to provide controlled and sustained release of paclitaxel locally. Expanded polytetrafluoroethylene (ePTFE) grafts were dipped twice into a solution of several different paclitaxel concentrations. In vitro release tests of the double dipping method showed that early burst release could be somewhat retarded and followed by sustained release for a long time. We observed the effect of paclitaxel coating by double dipping in porcine model of arterio-venous (AV) grafts between the common carotid artery and the external jugular vein. 12 weeks after constructing AV grafts, cross sections of the graft venous anastomosis were obtained and analyzed. Paclitaxel coated ePTFE grafts by double dipping were observed to prevent neointimal hyperplasia and therefore reduced stenosis of the arteriovenous hemodialysis grafts, especially at the graft venous anastomosis sites. Our results demonstrate that second dipping of ePTFE graft, which was already coated once with paclitaxel, washes off the drug on a surface of the graft and affects the ratio of paclitaxel on the surface to that of the inner space, possibly by diffusion: thus the early burst of drug can be somewhat reduced.

Hemodialysis Arteriovenous Fistula Patency Revisited

Vascular access standards are predominantly based on older, single-center reports; however, the hemodialysis population has changed dramatically and primary arteriovenous fistula failure is a huge problem. This prospective, multicenter study used standardized definitions to analyze patency rates and potential risk factors that affect functional patency and late arteriovenous fistula functionality. Eleven centers participated in a guidelines implementation program. All new permanent vascular accesses were included. Patency and functional patency, defined as access survival from creation and from first dialysis use, respectively, were calculated using Kaplan-Meier analysis. Risk factors for primary functional patency loss (intervention-free interval) and secondary failure (abandonment) were determined using regression models. A total of 491 arteriovenous fistulas were placed in 395 patients. Six-, 12-, and 18-mo secondary patency and functional patency were 75 +/- 2.0, 70 +/- 2.3, and 67 +/- 2.7% and 90 +/- 1.9, 88 +/- 2.2, and 86 +/- 2.7%, respectively. Primary failure rate was 40%. Thrombosis rate was 0.14 per patient-year. Diabetes and arteriovenous fistula surveillance were significantly associated with primary functional patency loss. Preoperative duplex was inversely related to secondary failure. The secondary failure rate per hospital varied from 0 to 39%. This study showed a marked difference between patency and functional patency, likely to be explained by high primary failure rates. Hemodialysis patients with diabetes can be expected to have reduced primary functional patency rates, but if treated adequately, then arteriovenous fistula functionality can be maintained as long as in patients without diabetes.