Dialysis Vascular Access Research Articles

Future directions for vascular access for hemodialysis.

Hemodialysis vascular access is at the same time both the "Lifeline" and the "Achilles Heel" of hemodialysis. This review will initially summarize the vascular biology of dialysis vascular access dysfunction and then use this information to describe some novel and innovative ways (including advances in the process of care for vascular access) to prevent this problem.

Home versus in-centre haemodialysis for end-stage kidney disease.

Home haemodialysis is associated with improved survival and quality of life in uncontrolled studies. However, relative benefits and harms of home versus in-centre haemodialysis in randomised controlled trials (RCTs) are uncertain. To evaluate the benefits and harms of home haemodialysis versus in-centre haemodialysis in adults with end-stage kidney disease (ESKD). The Cochrane Renal Group's Specialised Register was searched up to 31 October 2014. RCTs of home versus in-centre haemodialysis in adults with ESKD were included. Data were extracted by two investigators independently. Study risk of bias and other patient-centred outcomes were extracted. Insufficient data were available to conduct meta-analyses. We identified a single cross-over RCT (enrolling 9 participants) that compared home haemodialysis (long hours: 6 to 8 hours, 3 times/week) with in-centre haemodialysis (short hours: 3.5 to 4.5 hours, 3 times/weeks) for 8 weeks in prevalent home haemodialysis patients. Outcome data were limited and not available for the end of the first phase of treatment in this cross-over study which was at risk of bias due to differences in dialysate composition between the two treatment comparisons.Overall, home haemodialysis reduced 24 hour ambulatory blood pressure and improved uraemic symptoms, but increased treatment-related burden of disease and interference in social activities. Insufficient data were available for mortality, hospitalisation or dialysis vascular access complications or treatment durability. Insufficient randomised data were available to determine the effects of home haemodialysis on survival, hospitalisation, and quality of life compared with in-centre haemodialysis. Given the consistently observed benefits of home haemodialysis on quality of life and survival in uncontrolled studies, and the low prevalence of home haemodialysis globally, randomised studies evaluating home haemodialysis would help inform clinical practice and policy.

A Meta-analysis of Stent Placement vs. Angioplasty for Dialysis Vascular Access Stenosis.

Dysfunction of arteriovenous fistulas (AVF) and arteriovenous grafts (AVG) contribute significantly to morbidity and hospitalization in the dialysis population. Despite advances in endovascular techniques, the incidence of vascular access stenosis remains problematic. Currently, the role of endovascular stent placement in the treatment of vascular access stenosis is poorly defined. This meta-analysis compares the primary patency rates of stenotic vascular access treated with stent placement vs. angioplasty. We searched Medline for English language publications from 1980 through December 2013, along with national conference proceedings and reference lists of all included publications. Inclusion criteria were a measure of primary patency, secondary patency, or access dysfunction. Studies were excluded if they were not in English or if they included pediatric patients. Ten studies with a total of 860 subjects met the inclusion criteria, including six experimental studies and four observational studies. There was significantly higher overall primary patency in those receiving stent placement than in those treated with angioplasty (pooled relative risk [RR]=0.79; 95% confidence interval [CI]: 0.65-0.96). The estimate did not differ by study design. The effect of treatment differed significantly (p=0.001) by the type of stents used, however. In studies including nitinol stents (six studies, 678 patients), 6-month patency was significantly better for stent placement than angioplasty (pooled RR=0.67; 95% CI: 0.54-0.84), whereas there was no significant differences between stent placement and angioplasty in those studies using bare metal stents exclusively (four studies, 182 patients; pooled RR=1.09; 95% CI: 0.91-1.32). There was significant heterogeneity between studies (I(2) =70.6%; p<0.0001). Our results suggest that stent placement may confer an advantage over balloon angioplasty in primary patency of dialysis access stenoses.

News Update

Primary Teacher UpdateVol. 2014, No. 34 Regular ArticlesNews UpdateDorothy LepkowskaDorothy LepkowskaSearch for more papers by this authorDorothy LepkowskaPublished Online:13 Jun 2014https://doi.org/10.12968/prtu.2014.1.34.6AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article FiguresReferencesRelatedDetailsCited byA Meta-analysis of Stent Placement vs. Angioplasty for Dialysis Vascular Access Stenosis9 October 2014 | Seminars in Dialysis, Vol. 28, No. 3 2 July 2014Volume 2014Issue 34ISSN (print): 2047-8917ISSN (online): 2052-4609 Metrics History Published online 13 June 2014 Published in print 2 July 2014 Information© MA Education LimitedPDF download

Sonographic detection of a radiolucent object in dialysis vascular access

Percutaneous endovascular angioplasty is a valuable tool to salvage dialysis vascular access failure, but is accident-prone if performed by unskilled operators. We report a case of vascular access failure caused by the plastic protective tube of a balloon catheter, which had been mistakenly left in the vasculature and was undetectable on radiography but was detected by ultrasonography.

Novel Therapeutic Paradigms to Treat Hemodialysis Access Dysfunction

Vascular access dysfunction continues to be a major factor contributor to the morbidity and mortality of hemodialysis patient. Percutaneous intervention has been the central therapeutic modality used to treat dialysis vascular access dysfunction with limited success. Vascular biology research has shed considerable light on the pathophysiologic processes that lead to the development of neointimal hyperplasia, the culprit lesion for vascular access dysfunction, suggesting possible newer novel therapeutic interventions. In this review we discuss; (1) recent advances in the utilization of image based predictive medicine in improving access type selection prior to access creation; (2) current and promising treatment modalities including brachytherapy, gene therapy and pharmacotherapy for prevention of neointimal hyperplasia; (3) alternate imaging modalities during percutaneous endovascular interventions. Though novel therapeutic interventions are evolving, robust clinical studies to identify optimal therapeutic method are needed. A combination of evidenced based interventions from pre access creation up until final abandonment of vascular access is worthy of exploration.

Patient satisfaction with in-centre haemodialysis care: an international survey

ObjectivesTo evaluate patient experiences of specific aspects of haemodialysis care across several countries.DesignCross-sectional survey using the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) questionnaire.SettingHaemodialysis clinics within...

MP72-08 CELLULARIZED ELECTROSPUN VASCULAR GRAFTS FOR RENAL ARTERY RECONSTRUCTION

relatively low, it is expected to be much higher in this particular group. We routinely start anticoagulation therapy with these patients on the first day of the post operatory period. The aim of this study is to compare the effectiveness and the complications related to two different schemes of anticoagulation: prophylactic anticoagulation (PA) e 15,000 IU lowmolecular-weight heparin (LMWH) subcutaneous (sc) per day; and systemic anticoagulation (SA) e 30,000 IU LMWH continuously intravenous (iv) per day. METHODS: From January 2007 until September 2013, 1405 patients underwent renal transplantation in our center. Preemptive anticoagulation was indicated in 22 patients. Thirteen (59%) had identifiable thrombophilic disorders. For the other 9 patients, we either did not have time to conclude the investigation prior to transplantation, or the investigation yielded no diagnosis. Ten of these patients were prioritized due to precarious vascular access for dialysis. RESULTS: Patients in the SA group had a higher incidence of clinically important bleeding. These patients required more transfusions (4.7 1.9 vs. 0.53 0.92, p<0.001), and there were higher incidences of hemorrhagic shock (71.4% vs. 0.0%, p<0.001), hematoma (85.7% vs. 6.7%, p<0.01) and surgical re-intervention (71.4% vs. 13.3%, p1⁄40.017). There was one graft loss in the PA group (14.3%) and two in the SA group (20%). This difference was not statistically significant (p1⁄40.9). CONCLUSIONS: Systemic anticoagulation led to great increases in hemorrhagic complications and was not more effective in preventing graft loss when compared to prophylactic anticoagulation.

MP72-09 COMPARISON OF POSTOPERATIVE ESTIMATED GLOMERULAR FILTRATION RATE BETWEEN DONOR AND RADICAL NEPHRECTOMY PATIENTS AND RISK FACTORS OF POST-OPERATIVE CHRONIC KIDNEY DISEASE; A MULTI-CENTERED RETROSPECTIVE MATCHED CASE-CONTROL STUDY

relatively low, it is expected to be much higher in this particular group. We routinely start anticoagulation therapy with these patients on the first day of the post operatory period. The aim of this study is to compare the effectiveness and the complications related to two different schemes of anticoagulation: prophylactic anticoagulation (PA) e 15,000 IU lowmolecular-weight heparin (LMWH) subcutaneous (sc) per day; and systemic anticoagulation (SA) e 30,000 IU LMWH continuously intravenous (iv) per day. METHODS: From January 2007 until September 2013, 1405 patients underwent renal transplantation in our center. Preemptive anticoagulation was indicated in 22 patients. Thirteen (59%) had identifiable thrombophilic disorders. For the other 9 patients, we either did not have time to conclude the investigation prior to transplantation, or the investigation yielded no diagnosis. Ten of these patients were prioritized due to precarious vascular access for dialysis. RESULTS: Patients in the SA group had a higher incidence of clinically important bleeding. These patients required more transfusions (4.7 1.9 vs. 0.53 0.92, p<0.001), and there were higher incidences of hemorrhagic shock (71.4% vs. 0.0%, p<0.001), hematoma (85.7% vs. 6.7%, p<0.01) and surgical re-intervention (71.4% vs. 13.3%, p1⁄40.017). There was one graft loss in the PA group (14.3%) and two in the SA group (20%). This difference was not statistically significant (p1⁄40.9). CONCLUSIONS: Systemic anticoagulation led to great increases in hemorrhagic complications and was not more effective in preventing graft loss when compared to prophylactic anticoagulation.

Blood circulation in the fingers is aggravated after creating a vascular access for dialysis: assessment using skin perfusion pressure

Internal vascular shunts for haemodialysis can cause different complications. One of the most serious complications is steal syndrome, which can result in disturbed peripheral circulation causing finger necrosis and lead to amputation. Thus, prevention of these complications is important. Measurement of skin perfusion pressure (SPP) has been used in various clinical settings, including wound-healing management, and its usefulness has been increasingly unveiled. The present study was undertaken to evaluate changes in haemodynamics after internal shunt creation by measuring SPP of the thumb and the little finger before and after surgery in five patients undergoing shunt surgery using the radial artery and the cephalic vein. The study revealed average changes of −22.8 mmHg in thumb SPP. The change in the thumb was statistically significant (p < 0.05). If the effect of surgery and the threshold for wound healing are taken into account, the present results indicate the necessity to pay extra attention to fingers with extremely low preoperative SPP values. For the prevention of serious disturbances of peripheral circulation (e.g. steal syndrome), routine preoperative SPP measurement seems effective for screening of high-risk patients.

Convective Versus Diffusive Dialysis Therapies for Chronic Kidney Failure: An Updated Systematic Review of Randomized Controlled Trials

Convective dialysis therapies (hemofiltration or hemodiafiltration) are associated with lower mortality compared to hemodialysis in observational studies. A previous meta-analysis of randomized trials comparing convective modalities with hemodialysis in 2006 was inconclusive due to insufficient data. Additional randomized trials recently have reported conflicting results. Systematic review and meta-analysis of randomized trials to February 27, 2013. Patients with chronic kidney failure treated by hemodialysis, hemodiafiltration, hemofiltration, or biofiltration. Randomized controlled trials. Convective therapies (hemodiafiltration, hemofiltration, and acetate-free biofiltration) compared with hemodialysis. All-cause and cardiovascular mortality, nonfatal cardiovascular events, hospitalization, change in dialysis modality, health-related quality of life, adverse events, blood pressure, and clearances of urea and β2-microglobulin. 35 trials (4,039 participants) were included. In low-quality evidence, convective dialysis had little or no effect on all-cause mortality (relative risk [RR], 0.87; 95% CI, 0.70-1.07) and may reduce cardiovascular mortality (RR, 0.75; 95% CI, 0.58-0.97) and hypotension (RR, 0.72; 95% CI, 0.66-0.80) during dialysis, but had uncertain effects on nonfatal cardiovascular events (RR, 1.14; 95% CI, 0.85-1.52) and hospitalization (RR, 1.21; 95% CI, 0.12-12.05). Adverse events were not reported systematically and health-related quality-of-life outcomes were sparse. Convective therapies reduced predialysis levels of β2-microglobulin (mean difference, -5.77 [95% CI, -10.97 to -0.56]mg/dL) and increased dialysis dose (Kt/Vurea mean difference, 0.10; 95% CI, 0.02-0.19), but these effects were very heterogeneous. Sensitivity analyses limited to trials comparing hemodiafiltration with hemodialysis showed similar results. Studies had important risks of bias leading to low confidence in the summary estimates and generally were limited to patients who had adequate dialysis vascular access. Treatment effects of convective dialysis are unreliable due to limitations in trial methods and reporting. Convective dialysis may reduce cardiovascular but not all-cause mortality, and effects on nonfatal cardiovascular events and hospitalization are inconclusive.

Predicting dialysis vascular access blood flow and diameter: too much, too little, or just right

Arteriovenous fistula (AVF) maturation continues to cause significant morbidity and mortality. Despite the magnitude of the clinical problem, however, there are no effective clinical or biological predictors of AVF success or failure. Caroli et al. describe an innovative technology that may be successful in predicting AVF flow and diameter using standard-of-care preoperative inputs. Pending additional longer-term validation, the use of this technology could help us get the right access into the right patient at the right time.

Novel Paradigms for Dialysis Vascular Access

Nonmaturation of new arteriovenous fistulas (AVFs) remains a major barrier to increasing AVF use in hemodialysis patients ([1][1]). Our current clinical paradigm views nonmaturing AVF as a plumbing problem, with efforts directed at augmenting access flow by surgical or percutaneous interventions ([2

Clinical and Economic Value of Performing Dialysis Vascular Access Procedures in a Freestanding Office‐Based Center as Compared with the Hospital Outpatient Department among Medicare ESRD Beneficiaries

Dialysis vascular access (DVA) care is being increasingly provided in freestanding office-based centers (FOC). Small-scale studies have suggested that DVA care in a FOC results in favorable patient outcomes and lower costs. To further evaluate this issue, data were drawn from incident and prevalent ESRD patients within a 4-year sample (2006-2009) of Medicare claims (USRDS) on cases who receive at least 80% of their DVA care in a FOC or a hospital outpatient department (HOPD). Using propensity score matching techniques, cases with a similar clinical and demographic profile from these two sites of service were matched. Medicare utilization, payments, and patient outcomes were compared across the matched cohorts (n=27,613). Patients treated in the FOC had significantly better outcomes (p<0.001), including fewer related or unrelated hospitalizations (3.8 vs. 4.4), vascular access-related infections (0.18 vs. 0.29), and septicemia-related hospitalizations (0.15 vs. 0.18). Mortality rate was lower (47.9% vs. 53.5%) as were PMPM payments ($4,982 vs. $5,566). This study shows that DVA management provided in a FOC has multiple advantages over that provided in a HOPD.

Novel Paradigms for Dialysis Vascular Access

Vascular access dysfunction is a major cause of morbidity and mortality in hemodialysis patients. The most common cause of vascular access dysfunction is venous stenosis from neointimal hyperplasia within the perianastomotic region of an arteriovenous fistula and at the graft-vein anastomosis of an arteriovenous graft. There have been few, if any, effective treatments for vascular access dysfunction because of the limited understanding of the pathophysiology of venous neointimal hyperplasia formation. This review will (1) describe the histopathologic features of hemodialysis access stenosis; (2) discuss novel concepts in the pathogenesis of neointimal hyperplasia development, focusing on downstream vascular biology; (3) highlight future novel therapies for treating downstream biology; and (4) discuss future research areas to improve our understanding of downstream biology and neointimal hyperplasia development.

Novel paradigms for dialysis vascular access: upstream hemodynamics and vascular remodeling in dialysis access stenosis.

Failure of hemodialysis access is caused mostly by venous intimal hyperplasia, a fibro-muscular thickening of the vessel wall. The pathogenesis of venous neointimal hyperplasia in primary arteriovenous fistulae consists of processes that have been identified as upstream and downstream events. Upstream events are the initial events producing injury of the endothelial layer (surgical trauma, hemodynamic shear stress, vessel wall injury due to needle punctures, etc.). Downstream events are the responses of the vascular wall at the endothelial injury that consist of a cascade of processes including leukocyte adhesion, migration of smooth muscle cells from the media to the intimal layer, and proliferation. In arteriovenous fistulae, the stenoses occur in specific sites, consistently related to the local hemodynamics determined by the vessel geometry and blood flow pattern. Recent findings that the localization of these sites matches areas of disturbed flow may add new insights into the pathogenesis of neointimal hyperplasia in the venous side of vascular access after the creation of the anastomosis. The detailed study of fluid flow motion acting on the vascular wall in anastomosed vessels and in the arm vasculature at the patient-specific level may help to elucidate the role of hemodynamics in vascular remodeling and neointimal hyperplasia formation. These computational approaches may also help in surgical planning for the amelioration of clinical outcome. This review aims to discuss the role of the disturbed flow condition in acting as upstream event in the pathogenesis of venous intimal hyperplasia and in producing subsequent local vascular remodeling in autogenous arteriovenous fistulae used for hemodialysis access. The potential use of blood flow analysis in the management of vascular access is also discussed.

Dialysis Vascular Access and Lean Management

Vascular access (VA) is the key point to obtain an efficient dialysis, since VA dysfunction can hinder efficacy by increasing costs and hospitalization time, and by worsening quality of life. Costs of VA are increasing, due to the development of new grafts, catheters, and stents, and the increasing number of old patients. A global strategy to contain costs in this field requires a solid and consistent strategy of process management. The Toyota Production System could offer a method to analyze VA from a patient-oriented point of view, by means of identifying wastes and value stream during the process. Vascular burden of at-risk patients (chronic disease, frequent hospital stay) must be protected by skilled nurses. Late referral must be constrained to low figures by controlling the territory and allowing the planning of internal native VA. Residual CVC must be evaluated for AVF conversion, and a hierarchy among AVF, AVG and CVC must be established and respected. Finally, angioplasty and stents must be used in selected cases. CVC appear to be the main waste, while AV fistula is the access with maximum added value. Such a complex activity, involving many professionals, fits very well with a low volume/high quality industry model, and is based on the empowerment of each professional along the production chain. The multi-professional model requires a coordinator able to guide the patient along a pathway composed by the classical steps of planning, monitoring, clinical discussion, and corrective measures. It is our opinion that a senior nurse could be the right professional to do this job, as suggested by the model implemented in organ transplantation.

Arteriovenous Fistula Failure: Is There a Role for Epigenetic Regulation?

Epigenetics is the study of heritable changes in gene expression or cellular phenotype that occur without alterations in the DNA sequence. In the past decade, epigenetics has been identified as a key regulator of gene expression and therefore is likely to play a major role in multiple disease processes. More importantly, we now recognize epigenetics to be a sensitive, dynamic, and reversible process that has opened the door to multiple novel diagnostic, prognostic, and therapeutic strategies for human diseases. The focus of this review, however, is to explore the potential role of epigenetics in arteriovenous fistula (AVF) maturation. AVF maturation failure is currently the single most important cause of dialysis vascular access dysfunction and most important is the result of a peri-anastomotic stenosis thought to be caused by a combination of neointimal hyperplasia and inadequate outward remodeling. At a pathogenetic level, however, AVF maturation failure is likely the end result of the interaction between hemodynamic stressors (injury) and the vascular response to these stressors; the latter being influenced by uremia, oxidative stress, and inflammation. Interestingly, these same factors (hemodynamic shear stress, oxidative stress, inflammation, and uremia) are also important mediators of epigenetic modifications. We therefore believe that epigenetic factors potentially could play an important role in the pathogenesis of AVF maturation failure. The current review therefore tries to unravel some of these critical biological connections, with an emphasis on the future development of epigenetic-based diagnostic and therapeutic strategies for AVF maturation failure (a clinical problem for which there are currently no effective therapeutic interventions).

Interventional Nephrology

The prospective recognition of stenosis affecting dialysis vascular access and its prospective treatment is important in the management of the hemodialysis patient. Surveillance by physical examination is easily learned, easily performed, quickly done, and economical. In addition, it has a level of accuracy and reliability equivalent to other approaches that require special instrumentation. Physical examination should be part of any education to all hemodialysis care givers. This review presents the basic principles of physical examination of the hemodialysis vascular access and discusses the evidence behind its value.

Short Term Outcome of Brachial Plexus Block in Vascular Access Surgery

Objective: To present short term outcome of brachial plexus block for upper limb vascular access procedures performed for renal dialysis. Methods: This is a retrospective review of all cases that had a brachial plexus block for a renal dialysis vascular access procedure at the vascular surgery unit in King Hussein Medical Center, Amman, Jordan, between January 2009 and September 2011. Two hundred eighty- eight patients (172 males, 116 females) with a mean age of 41 (19-68) years had the block. In 183 (63.5%) patients the procedure was primary and in 75 (26.0 %) patients it was native access. Procedures performed included: 27 (9.4%) brachio-cephalic arteriovenous fistula, 48 (16.7%) basilic vein transposition, 96 (33.3%) forearm prosthetic loop graft, 67 (23.3%) upper arm prosthetic loop graft, 25 (8.7%) salvage procedures with interposition prosthetic grafts, 14 (4.9%) removal of infected prosthetic grafts, and 11 (3.8%) repairs of false aneurysms and disrupted anastomoses. All blocks were guided by a nerve stimulator at strength of 0.2-0.5MHZ and Bupivacaine 0.375 (25-35 ml) used for the block. Supraclavicular block was used in 132 (45.8%) patients while combined supraclavicular and axillary blocks were used in 156 (54.2%) patients. When local anesthetic infiltration was needed for supplementation of the block, Lignocaine 1% (10-15 ml) was used. Data regarding the procedure, adequacy of the block, time of onset, duration of block, and immediate complications was retrospectively collected from anesthetic charts and operative records. Results: All patients had an adequate block with no conversions to general anesthesia or cancellation of the procedure. A successful block was achieved in 232 (80.6%) patients while a partially successful block was achieved in 56 (19.4%) patients. The median time for onset of the block was 10 (5-20) minutes for motor block and 15 (10-35) minutes for sensory block. The mean duration of the block was 5.6 (2.2-48.0) hours. Prolonged blocks beyond 24 hours occurred in 5 patients (48 hours in 1 patient, 36 hours in 1 patient, and 24 hours in 3 patients). Injection related complications included discomfort during injection in 100 (34.7%) patients and local hematomas relieved by compression in 8 (2.8%) patients). Transient nerve paralysis complicated 82 (28.5%) cases (phrenic nerve in 57 (19.8%) patients, sympathetic chain resulting in Horner’s syndrome in 20 (6.9%) patients and vagus nerve resulting in hoarseness of voice in 5 (1.7%) patients). No clinically detectable pneumothorax or drug toxicity occurred. No peri-operative mortality was reported during the study period.