The Hemodialysis Access Surveillance Controversy Continues.
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ABSTRACT:
SUBMITTER: Anvari E
PROVIDER: S-EPMC7529591 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:IntroductionArteriovenous (AV) access thrombosis remains 1 of the most troubling AV access-related complications affecting hemodialysis patients. It necessitates an urgent and occasionally complicated thrombectomy procedure and increases the risk of AV access loss. AV access stenosis is found in the majority of thrombosed AV accesses. The routine use of AV access surveillance for the early detection and management of stenosis to reduce the thrombosis rate remains controversial.MethodsWe have conducted a multicenter, prospective, randomized clinical trial comparing the standard of care coupled with ultrasound dilution technique (UDT) flow measurement monthly surveillance with the standard of care alone.ResultsWe prospectively randomized 436 patients with end-stage renal disease on hemodialysis with arteriovenous fistula (AVF) or arteriovenous graft (AVG) using cluster (shift) randomization to surveillance and control groups. There were no significant differences in the baseline demographic data between the 2 groups, except for ethnicity (P = 0.017). Patients were followed on average for 15.2 months. There were significantly less per-patient thrombotic events (Poisson rate) in the surveillance group (0.12/patient) compared with the control group (0.23/patient) (P = 0.012). There was no statistically significant difference in the total number of procedures between the 2 groups, irrespective of whether thrombectomy procedures were included or excluded, and no statistically significant differences in the rate of or time to the first thrombotic event or the number of catheters placed due to thrombosis.ConclusionThe use of UDT flow measurement monthly AV access surveillance in this multicenter randomized controlled trial reduced the per-patient thrombotic events without significantly increasing the total number of angiographic procedures. Even though there is a trend, surveillance did not reduce the first thrombotic event rate.
| S-EPMC7609971 | biostudies-literature
Project description:The rise in prevalence of end stage renal disease (ESRD) and the impact on health care resulted in increasing focus on delivery of vascular access. Hemodialysis vascular access is the most common renal replacement therapy method. The vascular access types include arteriovenous fistula, arteriovenous graft, and tunneled central venous catheters. Vascular access function remains an important outcome measure with significant impact on morbidity and health care cost. The survival and quality of life of patients on hemodialysis is dependent on the adequacy of dialysis through proper vascular access. Early detection of failure to mature vascular access, stenosis, thrombosis, and aneurysm or pseudoaneurysm formation remains crucial. Ultrasound can help identify complications, even though ultrasound evaluation of the arteriovenous access is less well defined. Some published vascular access guidelines support ultrasound for detecting stenosis. The evolution of ultrasound has improved throughout the years, both multi parametric top-line systems and hand-held systems. Ultrasound evaluation is inexpensive, rapid, noninvasive, and repeatable, it is a powerful tool used for early diagnosis. The ultrasound image quality still depends on the skill of the operator. Careful attention to technical details is needed and avoidance of several diagnostic pitfalls is necessary. This review is focused on the role of ultrasound for hemodialysis access surveillance, evaluation of maturation, detection of access complications, and aid with cannulation.
| S-EPMC9971298 | biostudies-literature
Project description:Most arteriovenous grafts fail due to irreversible thrombosis, and most clotted grafts have an underlying stenotic lesion. These observations raise the plausible hypothesis that early detection of graft stenosis with preemptive angioplasty will reduce the likelihood of graft thrombosis. A number of noninvasive methods can be used to detect hemodynamically significant graft stenosis with a high positive predictive value. These tests include clinical monitoring, as well as surveillance by static dialysis venous pressures, flow monitoring, or duplex ultrasound. However, these surveillance tests have a much lower positive predictive value for graft thrombosis in the absence of preemptive angioplasty. In other words, none of the currently available surveillance tests can reliably distinguish between stenosed grafts destined to clot, and those that will remain patent without intervention. As a consequence, any program of graft surveillance necessarily results in a substantial proportion of unnecessary angioplasties. Moreover, a substantial proportion of grafts thrombose despite a normal antecedent surveillance test. Numerous observational studies have found an impressive reduction of graft thrombosis after implementation of a stenosis surveillance program. In contrast, 5 of 6 randomized clinical trials failed to show a reduction of graft thrombosis in patients undergoing graft surveillance, as compared with those receiving only clinical monitoring. The lack of benefit of surveillance is largely attributable to the rapid recurrence of stenosis after angioplasty. Thus, routine surveillance for graft stenosis, with preemptive angioplasty, cannot be recommended for reduction of graft thrombosis. Future research should be directed at pharmacologic interventions to prevent graft stenosis.
| S-EPMC4017945 | biostudies-literature
Project description:Rationale & objectiveAccess patency outcomes for arteriovenous fistulas (AVFs) as compared with arteriovenous grafts (AVGs) in patients receiving hemodialysis (HD) who have achieved a functioning permanent access are not fully explored.Study designObservational cohort study.Setting & populationFee-for-service Medicare beneficiaries aged ≥18 years with kidney failure who were newly using a permanent access for maintenance HD from the United States Renal Data System (2010-2015). Patients using an oral anticoagulant were excluded.ExposureAVG or AVF.OutcomesLoss of primary unassisted, primary assisted, and secondary patency.Analytical approachOutcomes were characterized using cumulative incidence curves, and HRs adjusted for sociodemographic and clinical factors were estimated for the comparison of AVF versus AVG.ResultsThe cohort included 60,329 and 17,763 patients newly using an AVF and AVG, respectively, for HD. Over 3 years of follow-up, AVG users, compared to AVF users, had a higher cumulative incidence of loss of primary unassisted patency (87% vs 69%; HR, 1.56; 95% CI, 1.52-1.60), loss of primary assisted patency (69% vs 25%; HR, 3.79; 95% CI, 3.67-3.92), and loss of secondary patency (22% vs 10%; HR, 2.03; 95% CI, 1.92-2.16). Stratified analyses revealed differences by subgroups; in particular, incidence of patency loss was higher among patients who underwent prior interventions to maintain prefunctional access patency and Black patients.LimitationsThis analysis focused on outcomes occurring after first successful use of a permanent access and thus does not inform about risk of patency loss during access maturation.ConclusionsAmong patients with kidney failure who successfully used a permanent access for HD, patency loss was consistently substantially higher in those using AVGs compared with AVFs. New interventions, such as prophylactic drugs, are needed to improve access longevity and reduce the need for invasive interventions, particularly among patients unable to receive a fistula.
| S-EPMC9829958 | biostudies-literature
Project description:INTRODUCTION:Central venous catheters (CVC) increase risks associated with hemodialysis (HD), but may be necessary until an arteriovenous fistula (AVF) or graft (AVG) is achieved. The impact of vascular imaging on achievement of working AVF and AVG has not been firmly established. METHODS:Retrospective cohort of patients initiating HD with CVC in 2010-2011, classified by exposure to venography or Doppler vein mapping, and followed through December 31, 2012. Standard and time-dependent Cox models were used to determine hazard ratios (HRs) of death, working AVF, and any AVF or AVG. Logistic regression was used to assess the association of preoperative imaging with successful AVF or AVG among 18,883 individuals who had surgery. Models were adjusted for clinical and demographic factors. FINDINGS:Among 33,918 patients followed for a median of 404 days, 39.1% had imaging and 55.7% had surgery. Working AVF or AVG were achieved in 40.6%; 46.2% died. Compared to nonimaged patients, imaged patients were more likely to achieve working AVF (HR?=?1.45 [95% confidence interval [CI] 1.36, 1.55], P?<?0.001]), any AVF or AVG (HR?=?1.63 [1.58, 1.69], P?>?0.001), and less likely to die (HR?=?0.88 [0.83-0.94], P?<?0.001). Among patients who had surgery, the odds ratio for any successful AVF or AVG was 1.09 (1.02-1.16, P?=?0.008). DISCUSSION:Fewer than half of patients who initiated HD with a CVC had vascular imaging. Imaged patients were more likely to have vascular surgery and had increased achievement of working AV fistulas and grafts. Outcomes of surgery were similar in patients who did and did not have imaging.
| S-EPMC5438785 | biostudies-literature
Project description:The arteriovenous fistula has been used for more than 50 years to provide vascular access for patients undergoing hemodialysis. More than 1.5 million patients worldwide have end stage renal disease and this population will continue to grow. The arteriovenous fistula is the preferred vascular access for patients, but its patency rate at 1 year is only 60%. The majority of arteriovenous fistulas fail because of intimal hyperplasia. In recent years, there have been many studies investigating the molecular mechanisms responsible for intimal hyperplasia and subsequent thrombosis. These studies have identified common pathways including inflammation, uremia, hypoxia, sheer stress, and increased thrombogenicity. These cellular mechanisms lead to increased proliferation, migration, and eventually stenosis. These pathways work synergistically through shared molecular messengers. In this review, we will examine the literature concerning the molecular basis of hemodialysis vascular access malfunction.
| S-EPMC4734360 | biostudies-literature
Project description:Frequent hemodialysis requires using the vascular access more often than with conventional hemodialysis, but whether this increases the risk for access-related complications is unknown. In two separate trials, we randomly assigned 245 patients to receive in-center daily hemodialysis (6 days per week) or conventional hemodialysis (3 days per week) and 87 patients to receive home nocturnal hemodialysis (6 nights per week) or conventional hemodialysis, for 12 months. The primary vascular access outcome was time to first access event (repair, loss, or access-related hospitalization). Secondary outcomes were time to all repairs and time to all losses. In the Daily Trial, 77 (31%) of 245 patients had a primary outcome event: 33 repairs and 15 losses in the daily group and 17 repairs, 11 losses, and 1 hospitalization in the conventional group. Overall, the risk for a first access event was 76% higher with daily hemodialysis than with conventional hemodialysis (hazard ratio [HR], 1.76; 95% confidence interval [CI], 1.11-2.79; P=0.017); among the 198 patients with an arteriovenous (AV) access at randomization, the risk was 90% higher with daily hemodialysis (HR, 1.90; 95% CI, 1.11-3.25; P=0.02). Daily hemodialysis patients had significantly more total AV access repairs than conventional hemodialysis patients (P=0.011), with 55% of all repairs involving thrombectomy or surgical revision. Losses of AV access did not differ between groups (P=0.58). We observed similar trends in the Nocturnal Trial, although the results were not statistically significant. In conclusion, frequent hemodialysis increases the risk of vascular access complications. The nature of the AV access repairs suggests that this risk likely results from increased hemodialysis frequency rather than heightened surveillance.
| S-EPMC3582201 | biostudies-literature
Project description:Background and objectivesFistulas, the preferred form of hemodialysis access, are difficult to establish and maintain. We examined the effect of a multidisciplinary vascular access team, including nurses, surgeons, and radiologists, on the probability of using a fistula catheter-free, and rates of access-related procedures in incident patients receiving hemodialysis.Design, setting, participants, & measurementsWe examined vascular access outcomes in the first year of hemodialysis treatment before (2004-2005, preteam period) and after the implementation of an access team (2006-2008, early-team period; 2009-2011, late-team period) in the Calgary Health Region, Canada. We used logistic regression to study the probability of fistula creation and the probability of catheter-free fistula use, and negative binomial regression to study access-related procedure rates.ResultsWe included 609 adults (mean age, 65 [±15] years; 61% men; 54% with diabetes). By the end of the first year of hemodialysis, 102 participants received a fistula in the preteam period (70%), 196 (78%) in the early-team period (odds ratios versus preteam, 1.47; 95% confidence interval, 0.92 to 2.35), and 139 (66%) in the late-team period (0.85; 0.54 to 1.35). Access team implementation did not affect the probability of catheter-free use of the fistula (odds ratio, 0.87; 95% confidence interval, 0.52 to 1.43, for the early; and 0.89; 0.52 to 1.53, for the late team versus preteam period). Participants underwent an average of 4-5 total access-related procedures during the first year of hemodialysis, with higher rates in women and in people with comorbidities. Catheter-related procedure rates were similar before and after team implementation; relative to the preteam period, fistula-related procedure rates were 40% (20%-60%) and 30% (10%-50%) higher in the early-team and late-team periods, respectively.ConclusionIntroduction of a multidisciplinary access team did not increase the probability of catheter-free fistula use, but resulted in higher rates of fistula-related procedures.
| S-EPMC5718268 | biostudies-literature
Project description:BACKGROUND AND OBJECTIVES:People receiving hemodialysis to treat kidney failure need a vascular access (a fistula, a graft, or a central venous catheter) to connect to the blood purification machine. Higher rates of access complications are considered the mechanism responsible for the excess mortality observed among catheter or graft users versus fistula users. We tested this hypothesis using mediation analysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:We studied incident patients who started hemodialysis therapy from North America, Europe, and Australasia (the Dialysis Outcomes and Practice Patterns Study; 1996-2011). We evaluated the association between access type and time to noninfectious (e.g., thrombosis) and infectious complications of the access (mediator model) and the relationship between access type and time-dependent access complications with 6-month mortality from the creation of the first permanent access (outcome model). In mediation analysis, we formally tested whether access complications explain the association between access type and mortality. RESULTS:Of the 6119 adults that we studied (mean age =64 [SD=15] years old; 58% men; 47% patients with diabetes), 50% had a permanent catheter for vascular access, 37% had a fistula, and 13% had a graft. During the 6-month study follow-up, 2084 participants (34%) developed a noninfectious complication of the access, 542 (8.9%) developed an infectious complication, and 526 (8.6%) died. Access type predicted the occurrence of access complications; both access type and complications predicted mortality. The associations between access type and mortality were nearly identical in models excluding and including access complications (hazard ratio, 2.00; 95% confidence interval, 1.55 to 2.58 versus hazard ratio, 2.01; 95% confidence interval, 1.56 to 2.59 for catheter versus fistula, respectively). In mediation analysis, higher mortality with catheters or grafts versus fistulas was not the result of increased rates of access complications. CONCLUSIONS:Hemodialysis access complications do not seem to explain the association between access type and mortality. Clinical trials are needed to clarify whether these associations are causal or reflect confounding by underlying disease severity.
| S-EPMC5460718 | biostudies-literature
Project description:Background and objectivesMedicare reimbursement policy encourages frequent provider visits to patients with ESRD undergoing hemodialysis. This study sought to determine whether more frequent face-to-face provider (physician and advanced practitioner) visits lead to more procedures and therapeutic interventions aimed at preserving arteriovenous fistulas and grafts, improved vascular access outcomes, and fewer related hospitalizations.Design, setting, participants, & measurementsMultivariable regression was used to evaluate the association between provider (physician and advanced practitioner) visit frequency and interventions aimed at preserving vascular access, vascular access survival, hospitalization for vascular access infection, and outpatient antibiotic use in a cohort of 63,488 Medicare beneficiaries receiving hemodialysis in the United States. Medicare claims were used to identify the type of vascular access used, access-related events, and vascular access failure.ResultsOne additional provider (physician and advanced practitioner) visit per month was associated with a 13% higher odds of receiving an intervention to preserve vascular access (95% confidence interval [95% CI], 12% to 14%) but was not associated with vascular access survival (hazard ratio, 1.01; 95% CI, 0.99 to 1.03). One additional provider visit was associated with a 9% (95% CI, 5% to 14%) lower odds of hospitalization for vascular access infection and a corresponding 9% (95% CI, 5% to 14%) higher odds of outpatient intravenous antibiotic administration. However, the associated changes in absolute probabilities of hospitalization and antibiotic administration were small.ConclusionsMore frequent face-to-face provider (physician and advanced practitioner) visits were associated with more procedures and therapeutic interventions aimed at preserving vascular accesses, but not with prolonged vascular access survival and only a small decrease in hospitalization for vascular access.
| S-EPMC4317740 | biostudies-literature