New Insights into Dialysis Vascular Access: What Is the Optimal Vascular Access Type and Timing of Access Creation in CKD and Dialysis Patients?
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ABSTRACT:
SUBMITTER: Woo K
PROVIDER: S-EPMC4974877 | biostudies-other | 2016 Aug
REPOSITORIES: biostudies-other
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Project description:Vascular access dysfunction remains a major cause of morbidity and mortality in hemodialysis patients. At present there are few effective therapies for this clinical problem. The poor understanding of the pathobiology that leads to arteriovenous fistula (AVF) and graft (AVG) dysfunction remains a critical barrier to development of novel and effective therapies. However, in recent years we have made substantial progress in our understanding of the mechanisms of vascular access dysfunction. This article presents recent advances and new insights into the pathobiology of AVF and AVG dysfunction and highlights potential therapeutic targets to improve vascular access outcomes.
| S-EPMC4974876 | biostudies-literature
Project description:Despite significant improvements in preoperative patient evaluation and surgical planning, vascular access failure in patients on hemodialysis remains a frequent and often unforeseeable complication. Our inability to prevent this complication is, in part, because of an incomplete understanding of how preexisting venous and arterial conditions influence the function of newly created arteriovenous fistulas and grafts. This article reviews the relationship between three preexisting vascular pathologies associated with CKD (intimal hyperplasia, vascular calcification, and medial fibrosis) and hemodialysis access outcomes. The published literature indicates that the pathogenesis of vascular access failure is multifactorial and not determined by any of these pathologies individually. Keeping this observation in mind should help focus our research on the true causes responsible for vascular access failure and the much needed therapies to prevent it.
| S-EPMC4974874 | biostudies-other
Project description:With the increasing life expectancy of patients with end-stage kidney disease, the creation and maintenance of hemodialysis vascular access are becoming more challenging. A comprehensive patient evaluation including a complete history, physical examination, and ultrasonographic vessel assessment is the foundation of the clinical evaluation. A patient-centered approach acknowledges the myriad of factors that impact the selection of optimal access for the distinct clinical and social circumstance of each patient. An interdisciplinary team approach involving various healthcare providers in all stages of hemodialysis access creation is important and associated with better outcomes. While patency is considered the most important parameter in most vascular reconstructive scenarios, the ultimate determinant of success in vascular access for hemodialysis is a circuit that allows consistent and uninterrupted delivery of the prescribed hemodialysis. The best conduit is one that is superficial, easily identified, straight, and of a large caliber. Individual patient factors and skill level of the cannulating technician also play a crucial role in the initial success and maintenance of vascular access. Special attention should be considered in dealing with more challenging groups such as the elderly population where the newest vascular access guidance from The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative will be transformative. The current guidelines recommend monitoring the vascular access by regular physical and clinical assessments, however, inadequate evidence is available to support routine ultrasonographic surveillance for improving access patency.
| S-EPMC9971302 | biostudies-literature
Project description:BackgroundLittle is known about the targets and expectations of practicing nephrologists with regard to timing of preemptive AV access surgery and how these relate to actual observed practice patterns in clinical care.MethodsWe administered a 8-question survey to assess nephrologists' expectations for preemptive vascular access placement to 53 practicing nephrologists in California. We performed a retrospective chart review of 116 patients who underwent preemptive vascular access placement at a large academic medical center and examined progression to ESRD.ResultsAccording to our survey of nephrologists, most aimed to have preemptive vascular access created about 6 months prior to start of ESRD or when the chances of ESRD within the next year is two-thirds or greater. The estimated GFR level at which they believe match these conditions is approximately 18 ml/min/1.73 m2. Among the 116 patients with CKD who underwent preemptive vascular access creation, the mean estimated GFR at the time of access creation was 16.1 (6.8) ml/min/1.73 m2. Only 57 out of the 116 patients (49.1%) patients initiated maintenance HD within 1 year after surgery.ConclusionsIn our study, most nephrologists aim for preemptive vascular access surgery approximately 6 months prior to the start of HD. However in fact, only approximately 50% of patients who underwent preemptive vascular access surgery started HD within 1 year. Better tools are needed to predict the natural history of advanced CKD.
| S-EPMC3671964 | biostudies-literature
Project description: Not available
| S-EPMC9366363 | biostudies-literature
Project description:Since the arteriovenous fistula (AVF) was first conceived over 50 years ago, the goal to create a vascular conduit with predictable and reproducible maturation and durability continues to elude caregivers. Recently, however, advances in the understanding of vascular biology and new technologies now provides us with some optimism; we are moving toward a viable solution. A quickly maturing, sustainable, and durable arteriovenous access may soon be attainable. This review will discuss these advances. There are novel approaches to AVF creation and devices to enhance maturation, advances in arteriovenous graft material(s), and devices to safely prolong the use of tunneled dialysis catheters. Although hemodialysis (HD) access remains a complex problem, these innovations may lead the way to optimizing the care and the quality of life of those patients who have no choice but to proceed with HD.
| S-EPMC7270716 | biostudies-literature
Project description:BackgroundPrevious observational studies examining outcomes associated with the timing of dialysis therapy initiation in the United States have often been limited by lead time and survivor bias.Study designRetrospective cohort study comparing the effectiveness of early versus later (conventional) dialysis therapy initiation in advanced chronic kidney disease (CKD). The analysis used inverse probability weighting to account for an individual's contribution to different exposure groups over time in a pooled logistic regression model. Patients contributed risk to both exposure categories (early and later initiation) until there was a clear treatment strategy (ie, dialysis therapy was initiated early or estimated glomerular filtration rate [eGFR] decreased to <10mL/min/1.73m(2)).Setting & participantsPatients with CKD who had at least one face-to-face outpatient encounter with a Cleveland Clinic health care provider as of January 1, 2005, and at least 3 eGFRs in the range of 20-30mL/min/1.73m(2) measured at least 180 days apart.PredictorsTiming of dialysis therapy initiation as determined using model-based interpolation of eGFR trajectories over time. Timing was defined as early (interpolated eGFR at dialysis therapy initiation≥10mL/min/1.73m(2)) or later (eGFR < 10mL/min/1.73m(2)) and was time-varying.OutcomesDeath from any cause occurring from the time that eGFR was equal to 20mL/min/1.73m(2) through September 15, 2009.ResultsThe study population consisted of 652 patients meeting inclusion criteria. Most (71.3%) of the study population did not initiate dialysis therapy during follow-up. Patients who did not initiate dialysis therapy (n=465) were older, more likely to be white, and had more favorable laboratory profiles than those who started dialysis therapy. Overall, 146 initiated dialysis early and 80 had eGFRs decrease to <10mL/min/1.73m(2). Many participants (n=426) were censored prior to attaining a clear treatment strategy and were considered undeclared. There was no statistically significant survival difference for the early compared with later initiation strategy (OR, 0.85; 95% CI, 0.65-1.11).LimitationsInterpolated eGFR, moderate sample size, and likely unmeasured confounders.ConclusionsIn patients with advanced CKD, timing of dialysis therapy initiation was not associated with mortality when accounting for lead time bias and survivor bias.
| S-EPMC4117406 | biostudies-literature
Project description:Determinants of nonfunctional arteriovenous (AV) access, including timing of AV access creation, have not been sufficiently described. We studied 29 945 patients who had predialysis AV access placement and were included in the French REIN registry from 2005 through 2013. AV access was considered nonfunctional when dialysis began with a catheter. We estimated crude and adjusted odds ratio (OR) with 95% confidence intervals (CI) of nonfunctional versus functional AV access associated with case-mix, facility characteristics, and timing of AV access creation. Analyses were stratified by dialysis start condition (planned or as an emergency) and comorbidity profile. Overall, 18% patients had nonfunctional AV access at hemodialysis initiation. In the group with planned dialysis start, female gender (OR 1.43, 95% CI 1.32-1.56), diabetes (OR 1.28, 95% CI 1.15-1.44), and a higher number of cardiovascular comorbidities (OR 1.27, 95% CI 1.09-1.49, and 1.31, 1.05-1.64, for 3 and >3 cardiovascular comorbidities versus none, respectively) were independent predictors of nonfunctional AV access. A higher percentage of AV access creation at the region level was associated with a lower rate of nonfunctional AV access (OR 0.98, 95% CI 0.98-0.99 per 1% increase). The odds of nonfunctional AV access decreased as time from creation to hemodialysis initiation increased up to 3 months in nondiabetic patients with fewer than 2 cardiovascular comorbidities and 6 months in patients with diabetes or 2 or more such comorbidities. In conclusion, both patient characteristics and clinical practices may play a role in successful AV access use at hemodialysis initiation. Adjusting the timing of AV access creation to patients' comorbidity profiles may improve functional AV access rates.
| S-EPMC5531527 | biostudies-literature
Project description:IntroductionThe last decade has seen a steady increase worldwide in the prevalence of end-stage renal disease (ESRD). Hemodialysis is the major modality of renal replacement therapy (RRT) in 70% to 90% of patients, who require well-functioning vascular access for this procedure. The recommended access for hemodialysis is an arteriovenous fistula or a vascular graft. However, recourse to central venous catheters remains essential for patients whose chronic renal disease is diagnosed at the end stage or in whom an arteriovenous fistula cannot be created or maintained. Tunneled dialysis catheter (TDC) exposure can induce venous stenosis and occlusions and can result in superior vena cava syndrome and/or vascular access loss. Exhaustion of conventional vascular accesses is 1 of the greatest challenges that nephrologists and patients have to face. Several unconventional salvage-therapy routes for TDC placement in patients with exhausted upper body venous access have been reported in the literature.MethodsWe report 2 new cases of intra-atrial TDC placement for patients with exhausted vascular access and perform a meta-analysis of cases from the literature.ResultsA total of 51 patients were included. The TDC was inserted by a cardiovascular surgeon in all cases. At the end of follow-up, 75% patients were alive. The median survival time was 25 months. Survival time of hemodialysis patients with intra-atrial TDC was lower than that observed with conventional TDC.ConclusionsThis unconventional technique is safe and functional for hemodialysis patients with exhausted venous access. Atrial vascular access for TDC placement is salvage therapy and is therefore potentially lifesaving.
| S-EPMC7335951 | biostudies-literature
Project description:Background and objectivesThere is increasing evidence that microRNAs (miRNAs) play crucial roles in the regulation of neointima formation. However, the translational evidence of the role of miRNAs in dialysis vascular access is limited.Design, setting, participants, & measurementsmiRNA expression in tissues was assessed by using venous tissues harvested from ten patients on dialysis who received revision or removal surgery, and ten patients who were predialysis and received creation surgery of arteriovenous fistulas served as controls. To extend these findings, 60 patients who received angioplasty of dialysis access were enrolled and the levels of circulating miRNAs were determined before and 2 days after angioplasty. Clinical follow-up was continued monthly for 6 months. The primary outcome of angioplasty cohort was target lesion restenosis within 6 months after angioplasty.ResultsIn the surgery cohort, the expressions of miR-21, miR-130a, and miR-221 were upregulated in stenotic tissues, whereas those of miR-133 and miR-145 were downregulated. In situ hybridization revealed similar expression patterns of these miRNAs, localized predominantly in the neointima region. Twenty eight patients in the angioplasty cohort developed restenosis within 6 months. The levels of circulating miR-21, miR-130a, miR-221, miR-133, and miR-145 significantly increased 2 days after angioplasty. Kaplan-Meier plots showed that patients with an increase of miR-21 expression level >0.35 have a higher risk of patency loss (hazard ratio, 4.45; 95% confidence interval, 1.68 to 11.7). In a multivariable analysis, postangioplasty increase of miR-21 expression was independently associated with restenosis (hazard ratio, 1.20; 95% confidence interval, 1.07 to 1.35 per one unit increase of miR-21 expression level; P=0.001).ConclusionsCertain miRNAs are differentially expressed in the stenotic venous segments of dialysis accesses. An increase in blood miR-21 level with angioplasty is associated with a higher risk of restenosis.
| S-EPMC6237050 | biostudies-literature