Treatment of Metabolic Acidosis in Hemodialysis Patients Is Biased by Type of Vascular Access.
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SUBMITTER: Bock L
PROVIDER: S-EPMC9263232 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Background and objectivesThe optimal type of initial permanent access for hemodialysis among the elderly is controversial. Duration of central venous catheter dependence, patient comorbidities, and life expectancy are important considerations in whether to place an arteriovenous fistula or graft. We used an observational study design to compare clinical outcomes in elderly patients who initiated hemodialysis with a central venous catheter and subsequently had an arteriovenous fistula or graft placed.Design, setting, participants, & measurementsWe identified 9458 United States patients ages ≥67 years old who initiated hemodialysis from July 1, 2010 to June 30, 2011 with a central venous catheter and no secondary vascular access and then received an arteriovenous fistula (n=7433) or graft (n=2025) within 6 months. We evaluated key clinical outcomes during the 6 months after vascular access placement coincident with high rates of catheter use and used a matched propensity score analysis to examine patient survival.ResultsCentral venous catheter dependence was greater in every month during the 6-month period after arteriovenous fistula versus graft placement (P<0.001). However, rates of all-cause infection-related hospitalization (adjusted relative risk, 0.93; 95% confidence interval, 0.87 to 0.99; P=0.01) and bacteremia/septicemia-related hospitalization (adjusted relative risk, 0.90; 95% confidence interval, 0.82 to 0.98; P=0.02) were lower in the arteriovenous fistula versus graft group as was the adjusted risk of death (hazard ratio, 0.76; 95% confidence interval, 0.73 to 0.80; P<0.001).ConclusionsDespite extended central venous catheter dependence, elderly patients initiating hemodialysis with a central venous catheter who underwent arteriovenous fistula placement within 6 months had fewer hospitalizations due to infections and a lower likelihood of death than those receiving an arteriovenous graft.
| S-EPMC5672965 | biostudies-literature
Project description:Background and objectivesIn individuals undergoing in-center hemodialysis (HD), use of central venous catheters (CVCs) is associated with worse clinical outcomes compared with use of arteriovenous access. However, it is unclear whether a similar difference in risk by vascular access type is present in patients undergoing home HD.Design, setting, participants, & measurementsOur study examined the associations of vascular access type with all-cause mortality, hospitalization, and transfer to in-center HD in patients who initiated home HD from 2007 to 2011 in 464 facilities in 43 states in the United States. Patients were followed through December 31, 2011. Data were analyzed using competing risks hazards regression, with vascular access type at the start of home HD as the primary exposure in a propensity score-matched cohort (1052 patients; 526 with CVC and 526 with arteriovenous access).ResultsOver a median follow-up of 312 days, 110 patients died, 604 had at least one hospitalization, and 202 transferred to in-center hemodialysis. Compared with arteriovenous access use, CVC use was associated with higher risk for mortality (hazard ratio, 1.73; 95% confidence interval, 1.18 to 2.54) and hospitalization (hazard ratio, 1.19; 95% confidence interval, 1.02 to 1.39). CVC use was not associated with increased risk for transfer to in-center HD. The results of analyses in the entire unmatched cohort (2481 patients), with vascular access type modeled as a baseline exposure at start of home HD or a time-varying exposure, were similar. Analyses among a propensity score-matched cohort of patients undergoing in-center HD also showed similar risks for death and hospitalization with use of CVCs.ConclusionsIn a large cohort of patients on home HD, CVC use was associated with higher risk for mortality and hospitalization. Additional studies are needed to identify interventions which may reduce risk associated with use of CVCs among patients undergoing home HD.
| S-EPMC4741041 | 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:BACKGROUND:Arteriovenous fistulas (AVFs) are the preferred vascular access type in most hemodialysis patients. However, the optimal vascular access type in octogenarians and older (?80?years) hemodialysis patients remains widely debated given their limited life expectancy and lower AVF maturation rates. METHODS:Among incident hemodialysis patients receiving care in a large national dialysis organization during 2007-2011, we examined patterns of vascular access type conversion in 1 year following dialysis initiation in patients <80 versus ?80 years of age. Among a subcohort of patients ?80?years of age, we examined the association between vascular access type conversion and mortality using multivariable survival models. RESULTS:In the overall cohort of 100?804 patients, the prevalence of AVF/arteriovenous graft (AVG) as the primary vascular access type increased during the first year of hemodialysis, but plateaued thereafter. Among 8356 patients ?80?years of age and treated for >1 year, those with initial AVF/AVG use and placement of AVF from a central venous catheter (CVC) had lower mortality compared with patients with persistent CVC use. When the reference group was changed to patients who had AVF placement from a CVC in the first year of dialysis, those with initial AVF use had similar mortality. A longer duration of CVC use was associated with incrementally worse survival. CONCLUSIONS:Among incident hemodialysis patients ?80?years of age, placement of an AVF from a CVC within the first year of dialysis had similar mortality compared with initial AVF use. Our data suggest that initial CVC use with later placement of an AVF may be an acceptable option among elderly hemodialysis patients.
| S-EPMC7057539 | biostudies-literature
Project description:Hemodialysis vascular access recommendations promote arteriovenous (AV) fistulas first; however, it may not be the best approach for all hemodialysis patients, because likelihood of successful fistula placement, procedure-related and subsequent costs, and patient survival modify the optimal access choice. We performed a decision analysis evaluating AV fistula, AV graft, and central venous catheter (CVC) strategies for patients initiating hemodialysis with a CVC, a scenario occurring in over 70% of United States dialysis patients. A decision tree model was constructed to reflect progression from hemodialysis initiation. Patients were classified into one of three vascular access choices: maintain CVC, attempt fistula, or attempt graft. We explicitly modeled probabilities of primary and secondary patency for each access type, with success modified by age, sex, and diabetes. Access-specific mortality was incorporated using preexisting cohort data, including terms for age, sex, and diabetes. Costs were ascertained from the 2010 USRDS report and Medicare for procedure costs. An AV fistula attempt strategy was found to be superior to AV grafts and CVCs in regard to mortality and cost for the majority of patient characteristic combinations, especially younger men without diabetes. Women with diabetes and elderly men with diabetes had similar outcomes, regardless of access type. Overall, the advantages of an AV fistula attempt strategy lessened considerably among older patients, particularly women with diabetes, reflecting the effect of lower AV fistula success rates and lower life expectancy. These results suggest that vascular access-related outcomes may be optimized by considering individual patient characteristics.
| S-EPMC4279737 | 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: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:RATIONALE & OBJECTIVE:National vascular access guidelines recommend placement of arteriovenous fistulas (AVFs) over grafts (AVGs) in hemodialysis patients, but have not been comprehensively assessed in the elderly. We evaluated clinically relevant vascular access outcomes in elderly patients receiving an AVF or AVG after hemodialysis therapy initiation. STUDY DESIGN:Retrospective cohort study using national administrative data. SETTINGS & PARTCIPANTS:Claims data from the US Renal Data System of 9,458 US patients 67 years and older who initiated hemodialysis therapy from July 1, 2010, to June 30, 2011, with a catheter and received an AVF (n=7,433) or AVG (n=2,025) within the ensuing 6 months. PREDICTOR:Arteriovenous access subtype, AVF or AVG. OUTCOMES:Successful use of vascular access, interventions to make vascular access functional, duration of catheter dependence before successful use of vascular access, frequency of interventions, and abandonment after successful use of vascular access. ANALYTICAL APPROACH:Multivariable logistic regression analysis was used to compare the need for intervention before successful use of AVFs and AVGs, and negative bionomial regression was used to calculate the frequency of intervention after successful use of vascular access. RESULTS:Unsuccessful use of vascular access within 6 months of creation was higher for AVFs versus AVGs (51% vs 45%; adjusted HR, 1.86; 95% CI, 1.73-1.99). Interventions to make vascular access functional were greater in AVFs versus AVGs (42% vs 23%; OR, 2.66; 95% CI, 2.26-3.12). AVFs had a lower 1-year abandonment rate after successful use compared with AVGs (OR, 0.71; 95% CI, 0.62-0.83) and required one-fourth fewer interventions after successful use (relative risk, 0.75; 95% CI, 0.69-0.81). Patients receiving an AVF had substantially longer catheter dependence before successful use than those receiving an AVG (median time, 3 vs 1 month; P<0.001). LIMITATIONS:Residual confounding due to vascular access choice, restriction to an elderly population, and 1-year follow-up period. CONCLUSIONS:In elderly hemodialysis patients initiating hemodialysis therapy with a catheter, the optimal vascular access selection depends on tradeoffs between shorter catheter dependence and less frequent interventions to make the vascular access (AVG) functional versus longer access patency and fewer interventions after successful use of the vascular access (AVF).
| S-EPMC6153087 | biostudies-literature
Project description:The optimal vascular access type for elderly hemodialysis patients is controversial. We evaluated the impact of comorbidity burden on the association between vascular access type and mortality risk among 23,100 hemodialysis patients aged ?65 years from the Korean Society of Nephrology End-Stage Renal Disease registry data. Subjects were stratified into tertiles according to the simplified Charlson comorbidity index (sCCI), and the survival and hospitalization rates were compared with respect to vascular access type: arteriovenous fistula (AVF), arteriovenous graft (AVG), and central venous catheter (CVC). Among all tertiles of sCCI, CVC use showed highest risk of mortality than AVF use. In the lowest to middle tertile, no difference was observed in survival rates between the use of AVF and AVG. However, in the highest tertile, AVG use showed higher risk of mortality than AVF use. When subjects were classified according to a combination of sCCI tertile and access type (AVF vs. AVG), patients with the highest CCI with AVG showed 1.75-folded increased risk of mortality than those with the lowest sCCI with AVF. Hospitalization rates due to access malfunction were highest in patients with CVC in all sCCI tertiles. In the highest tertile, patients with AVG showed increased rates of hospitalization compared to those with AVF due to access malfunction. However, hospitalization rates due to access infection were highest in patients with AVG in all tertiles. The use of AVF may be of benefit and switching to AVF should be considered in elderly hemodialysis patients with a high burden of comorbidity.
| S-EPMC6890785 | biostudies-literature