A national cohort study on hemodialysis arteriovenous fistulas after kidney transplantation - long-term patency, use and complications

OBJECTIVE

To describe the long-term hemodialysis arteriovenous fistula (AVF) patency, incidence of AVF use, incidence and nature of AVF complications and surgery in patients after kidney transplantation.

PATIENTS AND METHODS

We retrospectively analysed the AVF outcome and complications in all adult kidney allograft recipients transplanted between January 1st, 2000 and December 31, 2015 with a functional AVF at the time of transplantation. Follow-up was until December 31, 2019.

RESULTS

We included 626 patients. Median AVF follow-up was 4.9 years. One month after kidney transplantation estimated AVF patency rate was 90%, at 1 year it was 82%, at 3 years it was 70% and at 5 years it was 61%; median estimated AVF patency was 7.9 years. The main cause of AVF failure was spontaneous thrombosis occurring in 76% of AVF failure cases, whereas 24% of AVFs were ligated or extirpated. In a Cox multivariate model female sex and grafts were independently associated with more frequent AVF thrombosis. AVF was used in about one third of our patients. AVF-related complications occurred in 29% of patients and included: growing aneurysms, complicated thrombosis, high-flow AVF, signs of distal hypoperfusion, venous hypertension, trauma of the AVF arm, or pain in the AVF/arm.

CONCLUSIONS

AVFs remain functional after kidney transplantation in the majority of patients and are often re-used after graft failure. AVF-related complications are common and require proper care.

Surgeon Factors Have a Larger Effect on Vascular Access Type and Outcomes than Patient Factors

BACKGROUND AND OBJECTIVES

Though patient factors are frequently linked to hemodialysis vascular access selection and outcomes, variability by surgeon and surgeon specialty may play a role as well. The objective of this study is to examine the extent to which individual surgeons influence selection of vascular access type, removal of tunneled hemodialysis catheter (THC), and repeat vascular access.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A national claims database was used to identify patients initiating hemodialysis via a THC between 2011 and 2017. Likelihood of repeat AVF/AVG was analyzed using mixed-effects logistic regression. Time from initial arteriovenous fistula (AVF)/graft (AVG) to THC removal and time to repeat AVF/AVG were analyzed using Weibull proportional hazard models. Individual surgeon identifier served as the random effect in all models.

RESULTS

6,908 AVF/AVG met the inclusion criteria: 5366 (78%) AVF and 1,542 (22%) AVG. Surgeon specialty only had a significant influence on access type, with vascular surgeons having 26% greater odds of performing AVG compared to general surgeons (P = 0.006). Relative to the other independent variables, individual surgeon identifier had the greatest magnitude of effect on access type (median odds ratio, 2.36; 95% CI, 2.09-2.72). Individual surgeon identifier had the second greatest magnitude of effect likelihood of THC removal (median hazard ratio, 1.66; 95% CI, 1.58-1.77) and second access (median hazard ratio, 1.83; 95% CI, 1.66-2.05), in both cases second only to the effect of AVG, which was associated with greater likelihood of THC removal (hazard ratio 1.91; 95% CI, 1.77-2.07) and lower likelihood of second access (hazard ratio 0.44; 95% CI, 0.38-0.52).

CONCLUSION

Individual surgeons are associated with greater variation in vascular access type and likelihood of repeat access than surgeon specialty and measurable patient demographics/co-morbidities. Future research should focus on identifying which surgeon factors are associated with improved outcomes.

Global Epidemiology of End-Stage Kidney Disease and Disparities in Kidney Replacement Therapy

BACKGROUND

The global epidemiology of end-stage kidney disease (ESKD) reflects each nation's unique genetic, environmental, lifestyle, and sociodemographic characteristics. The response to ESKD, particularly regarding kidney replacement therapy (KRT), depends on local disease burden, culture, and socioeconomics. Here, we explore geographic variation and global trends in ESKD incidence and prevalence and examine variations in KRT modality, practice patterns, and mortality. We conclude with a discussion on disparities in access to KRT and strategies to reduce ESKD global burden and to improve access to treatment in low- and middle-income countries (LMICs).

SUMMARY

From 2003 to 2016, incidence rates of treated ESKD were relatively stable in many higher income countries but rose substantially predominantly in East and Southeast Asia. The prevalence of treated ESKD has increased worldwide, likely due to improving ESKD survival, population demographic shifts, higher prevalence of ESKD risk factors, and increasing KRT access in countries with growing economies. Unadjusted 5-year survival of ESKD patients on KRT was 41% in the USA, 48% in Europe, and 60% in Japan. Dialysis is the predominant KRT in most countries, with hemodialysis being the most common modality. Variations in dialysis practice patterns account for some of the differences in survival outcomes globally. Worldwide, there is a greater prevalence of KRT at higher income levels, and the number of people who die prematurely because of lack of KRT access is estimated at up to 3 times higher than the number who receive treatment. Key Messages: Many people worldwide in need of KRT as a life-sustaining treatment do not receive it, mostly in LMICs where health care resources are severely limited. This large treatment gap demands a focus on population-based prevention strategies and development of affordable and cost-effective KRT. Achieving global equity in KRT access will require concerted efforts in advocating effective public policy, health care delivery, workforce capacity, education, research, and support from the government, private sector, nongovernmental, and professional organizations.

Clinical Utility Of Cavea2t2 Score For Assessing The Survival Of Brachiocephalic Arteriovenous Fistula

BACKGROUND

There are not many error proof clinical scores to assess the native dialysis access. CAVeA2T2 score is a recent tool in use. Objective of the study is to assess the clinical utility of CAVeA2T2 scoring system in predicting the survival rate of brachiocephalic arteriovenous fistula (BC-AVF).

METHODS

All consecutive patients fulfilling the inclusion criteria for BC-AVF from January 2016 to January 2018 were included. According to their CAVeA2T2 score they were divided into two groups (Group A: < 2 and Group B: ≥2). Cumulative primary and secondary patency survival of BC-AVF for both groups were measured.

RESULTS

A total of 112 BC-AVFs were analysed. Mean age was 42±SD 14 years (M: F =5:1). Mean CAVeA2T2 score was 1.45±1.8. In terms of primary patency, there was no statistically significant difference between two groups (p=0.074, p = 0.229 and p=0.357 at 6 weeks, 6 months and 12 months respectively). However, the difference was significant in terms of secondary patency (p=0.002, p=0.036 and p=0.032 at 6 weeks, 6 months and 12 months respectively). On comparing the cumulative survival between two groups; a significantly low primary patency rate survival (Log Rank x2 = 12.9, p-value = 0.001) and secondary patency rate survival (Log Rank x2 = 7.6, p-value = 0.001) of BC-AVF was found in Group B.

CONCLUSION

We found CAVeA2T2 score an easily applicable and useful tool to assess the patency and survival of BC-AVF. Patients have a poor patency and significantly low survival rate when their CAVeA2T2 score was ≥2.

Impact of Arteriovenous fistula creation on estimated glomerular filtration rate decline in Predialysis patients

BACKGROUND

Arteriovenous fistula (AVF) is the vascular access of choice for patients on hemodialysis. Recent evidence suggests that AVF creation may slow estimated glomerular filtration rate (eGFR) decline. The study objective was to assess the impact of the AVF creation on eGFR decline, after controlling for key confounding factors.

METHODS

This retrospective cohort study included adult patients followed in a single-center predialysis clinic between 1999 and 2016. Patients with a patent AVF were followed up to 2 years pre- and post-AVF creation. Estimated GFR trajectory was reported using linear mixed models adjusted for demographic characteristics, comorbidities and use of renin-angiotensin-aldosterone blockade.

RESULTS

A total of 146 patients were studied with a median age 68.7 (60.5-75.4) years and a median eGFR at time of AVF creation of 12.8 (11.3-13.9) mL/min/1.73m2. The crude annual eGFR decline rates were - 3.60 ± 4.00 mL/min/1.73 m2 pre- and - 2.28 ± 3.56 mL/min/1.73 m2 post-AVF, resulting in a mean difference of 1.28 mL/min/1.73 m2 (95% CI 0.49, 2.07). In a mixed effect linear regression model, monthly eGFR decline was - 0.63 (95% CI -0.81, - 0.46; p <  0.001) mL/min/1.73m2/month. The period after AVF creation was associated with a relatively higher eGFR (β 0.94, 95% CI 0.61-1.26, p <  0.001). There was a significant association between follow-up time and the period pre/post AVF (β 0.19, 95% CI 0.16, 0.22; p <  0.001) such that eGFR decline was more attenuated each month after AVF creation.

CONCLUSIONS

In this cohort, AVF creation was associated with a significant reduction of eGFR decline. Further prospective studies are needed to confirm this association.

Higher Surgeon Procedure Volume Is Associated with Improved Hemodialysis Vascular Access Outcomes

The objective of this study was to examine the association between surgeon characteristics, procedural volume, and short-term outcomes of hemodialysis vascular access. A retrospective cohort study was performed using Medicare Part A and B data from 2007 through 2014 merged with American Medical Association Physician Masterfile surgeon data. A total of 29,034 procedures met the inclusion criteria: 22,541 (78%) arteriovenous fistula (AVF) and 6,493 (22%) arteriovenous graft (AVG). Of these, 13,110 (45.2%) were performed by vascular surgeons, 9,398 (32.3%) by general surgeons, 2,313 (8%) by thoracic surgeons, 1,517 (5.2%) by other specialties, and 2,696 (9.3%) were unknown. Every 10-year increase in years in practice was associated with a 6.9 per cent decrease in the odds of creating AVF versus AVG (P = 0.02). Surgeon characteristics were not associated with the likelihood of vascular access failure. Every 10-procedure increase in cumulative procedure volume was associated with a 5 per cent decrease in the odds of vascular access failure (P = 0.007). There was no association of provider characteristics or procedure volume with survival free of repeat AVF/AVG or TC placement at 12 months. A significant portion of the variability in likelihood of creating AVF versus AVG is attributable to the provider-level variation. Increase in procedure volume is associated with decreased odds of vascular access failure.

Vascular access types in hemodialysis patients in palestine and factors affecting their distribution: A cross-sectional study

The incidence of end-stage renal disease (ESRD) patients is increasing considerably worldwide, and most of the patients start their therapy by hemodialysis (HD). Arteriovenous fistula (AVF) is the best type of vascular access due to its decreased rate of complications followed by arteriovenous graft (AVG) and finally, central venous catheters which are associated with increased mortality and morbidity. In this study, we aim to find out the proportion of each vascular access type used in HD patients and to evaluate the epidemiology of HD access in Palestine. Six hundred and fifty-eight patients were enrolled in this study from 10 dialysis units distributed in Palestine. The patients were divided into incident patients or prevalent patients. Data were collected by the researchers by regular visits to the units. AVFs were the most common access type (69.3%), catheters came second (27.8%) finally, AVGs (2.9%). Temporary catheters composed 59% of all catheters, followed by the permanent catheters. The subclavian vein was the most common insertion site (68.3%), internal jugular vein (26.8%), and femoral vein (4.9%). Temporary catheters were most commonly used among incident patients (41.5%) and AVFs were the most common in the prevalent patients (75%). There was no statistically significant association between the type of dialysis access use with gender, body mass index, or diabetic status. We recommend close follow-up and early AVF creation when the patients are expected to need HD. We also highly recommend decreasing the duration of temporary catheters. Finally, further prospective studies to follow-up and evaluate the progression in the vascular access status in Palestine are needed.

Vascular access outcome with a dedicated vascular team based approach

The objective of this study is to determine the impact of a dedicated vascular team in the early detection of complications and improvement of vascular access patency. A dedicated vascular access team comprised four dialysis nurses, a vascular access coordinator and led by a physician. They were assigned for the surveillance and care of all vascular accesses. The team presented problematic cases in the regular quality meeting with documentation of access blood flow, dynamic venous pressure, findings of hematoma, prolonged bleeding, swelling, low arterial pressures, steal syndrome, recirculation studies and dialysis adequacy. In case of failed recirculation or persistently elevated dynamic venous pressure, further evaluation was done either a fistulogram or review by a vascular surgeon. A total of 226 problematic vascular access cases were detected during the study (January 2014 to October 2017). The majority were in 41-70 years age group. A total of 248 referrals were given. Two hundred cases were referred for fistulogram, but it was performed in 188 patients. Vascular access stenosis was detected in 153 patients (81.3%) and angioplasty was performed in 137 (89.5%) of these patients. Fifteen (9.8%) patients were managed conservatively and one patient refused angioplasty. The 15 cases managed conservatively continued to work normally. One patient who refused to angioplasty later clotted his fistula during the follow-up period. Out of 41 cases who were totally noncompliant to referral, nine (22%) clotted their fistula during the follow-up period. In 12 cases in whom fistulogram was requested, but the request was declined by the primary hospital, five patients (41.6%) clotted their fistulas. Subgroup analysis showed that in patients who had both failed recirculation and high venous pressure, the prevalence of stenosis was 90% and angioplasty was performed in 94.4%. In patients who had failed recirculation and low arterial pressure, stenosis was detected in 85.7% and angioplasty was performed in 100% of cases. A dedicated vascular team approach for the care of dialysis vascular access helps in early identification of complications and improve vascular access outcome.

Gender Disparities in Vascular Access Surgical Outcomes in Elderly Hemodialysis Patients

BACKGROUND

Despite national vascular access guidelines promoting the use of arteriovenous fistulas (AVF) over arteriovenous grafts (AVGs) for dialysis, AVF use is substantially lower in females. We assessed clinically relevant AVF and AVG surgical outcomes in elderly male and female patients initiating hemodialysis with a central venous catheter (CVC).

METHODS

Using the United States Renal Data System standard analytic files linked with Medicare claims, we assessed incident hemodialysis patients in the United States, 9,458 elderly patients (≥67 years; 4,927 males and 4,531 females) initiating hemodialysis from July 2010 to June 2011 with a catheter and had an AVF or AVG placed within 6 months. We evaluated vascular access placement, successful use for dialysis, assisted use (requiring an intervention before successful use), abandonment after successful use, and rate of interventions after successful use.

RESULTS

Females were less likely than males to receive an AVF (adjusted likelihood 0.57, 95% CI 0.52-0.63). Among patients receiving an AVF, females had higher adjusted likelihoods of unsuccessful AVF use (hazard ratio [HR] 1.46, 95% CI 1.36-1.56), assisted AVF use (OR 1.34, 95% CI 1.17-1.54), and AVF abandonment (HR 1.28, 95% CI 1.10-1.50), but similar relative rate of AVF interventions after successful use (relative risk [RR] 1.01, 95% CI 0.94-1.08). Among patients receiving an AVG, females had a lower likelihood of unsuccessful AVG use (HR 0.83, 95% CI 0.73-0.94), similar rates of assisted AVG use (OR 1.05, 95% CI 0.78-1.40) and AVG abandonment, and greater relative rate of interventions after successful AVG use (RR 1.16, 95% CI 1.01-1.33).

CONCLUSIONS

While AVFs should be considered the preferred vascular access in most circumstances, clinical AVF surgical outcomes are uniformly worse in females. Clinicians should also consider AVGs as a viable alternative in elderly female patients initiating hemodialysis with a CVC to avoid extended CVC dependence.

Effect of Anti-Hypertensive Medication History on Arteriovenous Fistula Maturation Outcomes

BACKGROUND

The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis. However, approximately half of AVFs fail to mature. The use of angiotensin converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs), and calcium channel blockers (CCBs) exerts favorable endothelial effects and may promote AVF maturation. We tested associations of ACE-I and ARBs, CCBs, beta-blockers, and diuretics with the maturation of newly created AVFs.

METHODS

We evaluated 602 participants from the Hemodialysis Fistula Maturation Study, a multi-center, prospective cohort study of AVF maturation. We ascertained the use of each medication class within 45 days of AVF creation surgery. We defined maturation outcomes by clinical use within 9 months of surgery or 4 weeks of initiating hemodialysis.

RESULTS

Unassisted AVF maturation failure without intervention occurred in 54.0% of participants, and overall AVF maturation failure (with or without intervention) occurred in 30.1%. After covariate adjustment, CCB use was associated with a 25% lower risk of overall AVF maturation failure (95% CI 3%-41% lower) but a non-significant 10% lower risk of unassisted maturation failure (95% CI 23% lower to 5% higher). ACE-I/ARB, beta-blocker, and diuretic use was not significantly associated with AVF maturation outcomes. None of the antihypertensive medication classes were associated with changes in AVF diameter or blood flow over 6 weeks following surgery.

CONCLUSIONS

CCB use may be associated with a lower risk of overall AVF maturation failure. Further studies are needed to determine whether CCBs might play a causal role in improving AVF maturation outcomes.

Gender and Racial Disparities in Initial Hemodialysis Access and Outcomes in Incident End-Stage Renal Disease Patients

BACKGROUND

Arteriovenous (AV) access confers survival benefits over central venous catheters (CVC) in hemodialysis patients. Although chronic kidney disease disproportionately affects women and racial minorities, disparities in the -utilization of hemodialysis access across Asians, Native Americans, Hispanics, blacks, and whites among males and females after accounting for pre-dialysis health are not well studied.

METHODS

We evaluated 885,699 patients with end-stage renal disease who initiated hemodialysis between January 1, 2004 and December 31, 2014 using the US Renal Data System. Multivariable logistic regression models -adjusted for pre-dialysis health were used to test the associations between gender and race on type of vascular access (AV access vs. CVC, and AV fistula vs. AV graft) at hemodialysis initiation as primary outcome, and on 1-year mortality as a secondary outcome.

RESULTS

Mean age was 65 ± 14 years. Females were less likely to use AV access for hemodialysis initiation than were males (OR 0.85; 95% CI 0.84-0.86). Compared to whites, adjusted odds of AV access for hemodialysis initiation were higher in blacks (OR 1.08; 95% CI 1.07-1.70), Asians (OR 1.11; 95% CI 1.07-1.14); and lower in Hispanics (OR 0.89; 95% CI 0.87-0.90). There was no -significant difference in mortality between males and females. Compared to whites, 1-year adjusted mortality was lower in Asians (OR 0.55; 95% CI 0.53-0.56), blacks (OR 0.67; 95% CI 0.66-0.68), Hispanics (OR 0.62; 95% CI 0.61-0.63), and Native Americans (OR 0.62; 95% CI 0.58-0.66).

CONCLUSION

Females had lower odds of using AV access than do males for hemodialysis initiation. As compared to whites, blacks and Asians were more likely, and Hispanics were less likely to use AV access for first outpatient hemodialysis. Further investigation of biological and process of care factors may help in developing ways to reduce these disparities.

How Often Are Protocols Followed at Level I Trauma Centers?

This study analyzes adherence to an evidence-based protocol established at two level I trauma centers to determine its effect on clinical decision making. The centers' trauma databases were retrospectively studied and 51 patients with long bone fractures were identified who required revascularization and orthopaedic intervention and survived long enough to receive an index intervention. An arterial shunt was the protocol's first step; the preprotocol rate of shunting was 9.5%, while the postprotocol rate of shunting was 3.3%. The protocol's next step was external fixation; among the cases managed without a shunt, external fixation was the index intervention in 63.2% of the preprotocol cases and 31.0% of the postprotocol cases. Definitive vascular surgery was routinely performed before external fixation in 28.6% of the preprotocol cases and 56.7% of the postprotocol cases. This study demonstrates that this evidence-based protocol had no effect on the management of patients with combined orthopaedic and vascular injuries. Protocols should never supersede clinical judgment, but poor protocol adherence may represent a need for trauma centers to routinely review their protocols' compliance and efficacy. (Journal of Surgical Orthopaedic Advances 27(2):109-112, 2018).

Multi-Disciplinary Vascular Access Care and Access Outcomes in People Starting Hemodialysis Therapy

BACKGROUND AND OBJECTIVES

Fistulas, 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, & MEASUREMENTS

We 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.

RESULTS

We 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.

CONCLUSION

Introduction of a multidisciplinary access team did not increase the probability of catheter-free fistula use, but resulted in higher rates of fistula-related procedures.

Risk of Infective Endocarditis in Patients with End Stage Renal Disease

BACKGROUND AND OBJECTIVES

Endocarditis is a serious complication in patients treated with RRT. The study aimed to examine incidence and risk factors of endocarditis in patients with ESRD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Danish National Registry on Regular Dialysis and Transplantation contains data on all Danish patients receiving renal replacement (hemodialysis, peritoneal dialysis, or kidney transplantation) for ESRD. Incidence of endocarditis was estimated for each RRT modality. Independent risk factors of endocarditis were identified in multivariable Cox regression models.

RESULTS

From January 1st, 1996 to December 31st, 2012, 10,612 patients (mean age 63 years, 36% female) initiated RRT (7233 hemodialysis, 3056 peritoneal dialysis, 323 pre-emptive kidney transplantation). Endocarditis developed in 267 (2.5%); of these 31 (12%) underwent valve surgery. The overall incidence of endocarditis was 627 per 100,000 person-years in patients receiving RRT. Incidence was higher in patients receiving hemodialysis compared with those receiving peritoneal dialysis or kidney transplantation (1092 per 100,000 person-years, 212 per 100,000 person-years, and 85 per 100,000 person-years, respectively). Adjusted hazard ratios for endocarditis in patients receiving hemodialysis were 5.46 (95% confidence interval [95% CI], 3.28 to 9.10) and 0.41 (95% CI, 0.18 to 0.91) for kidney-transplanted recipients, respectively, as compared with patients in peritoneal dialysis. The incidence of endocarditis in hemodialysis recipients with central venous catheters was more than two-fold higher as compared with those with arteriovenous fistulas. Overall mortality, subsequent to endocarditis, was 22% in-hospital and 51% at 1 year. The first 6 months in RRT, aortic valve disease, and previous endocarditis were identified as significant risk factors of endocarditis.

CONCLUSIONS

Patients receiving RRT have a high incidence of endocarditis, in particular during hemodialysis treatment using central venous catheters. The first 6 months in RRT, aortic valve disease, and previous endocarditis are significant risk factors for developing endocarditis.

Vascular Access Type and Clinical Outcomes among Elderly Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

The 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, & MEASUREMENTS

We 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.

RESULTS

Central 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).

CONCLUSIONS

Despite 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.

Vascular Access Placement Order and Outcomes in Hemodialysis Patients: A Longitudinal Study

BACKGROUND

Arteriovenous accesses (AVA) in patients performing hemodialysis (HD) are labeled "permanent" for AV fistulas (AVF) or grafts (AVG) and "temporary" for tunneled central venous catheters (TCVC). Durability and outcomes of permanent vascular accesses based on the sequence in which they were placed or used receives little attention. This study analyzed longitudinal transitions between TCVC-based and AVA-based HD outcomes according to the order of placement.

METHODS

All 391 patients initiating chronic HD via a TCVC between 2012 and 2013 at 12 outpatient academic dialysis units were included in this study. Chronological distributions of HD vascular accesses were recorded over a mean (SD) of 2.8 (0.9) years and sequentially grouped into periods for TCVC-delivered and AVA-delivered (AVF or AVG) HD. Primary AVA failure and cumulative access survival were evaluated based on access placement sequence and type, adjusting for age.

RESULTS

In total, 92.3% (361/391) of patients underwent 497 AVA placement surgeries. Analyzing the initial 3 surgeries, primary AVF failure rates increased with each successive fistula placement (p = 0.008). Among the 82.9% (324/391) of TCVC patients successfully converted to an AVA, 30.9% returned to a TCVC, followed by a 58.0% conversion rate to another AVA. Annual per-patient vascular access transition rates were 2.02 (0.09) HD periods using a TCVC and 0.54 (0.03) HD periods using an AVA. Comparing the first AVA used with the second, cumulative access survivals were 701.0 (370.0) vs. 426.5 (275.0) days, respectively. Excluding those never converting to an AVF or AVG, 169 (52.2%) subsequently converted from a TCVC to a permanent access and received HD via AVA for ≥80% of treatments.

CONCLUSIONS

HD vascular access outcomes differ based on the sequence of placement. In spite of frequent AVA placements, only half of patients effectively achieved a "permanent" vascular access and used an AVA for the majority of HD treatments.

Nursing Care for Patients with Biological Arteriovenous Grafts

Patients receiving hemodialysis are challenged with maintaining adequate vascular access. Nephrology nurses are on the forefront of daily care, assessment, and monitoring of patients' vascular accesses for hemodialysis. This article discusses the literature and manufacturer information to support best nursing practices.

An Increase in Mean Platelet Volume/Platelet Count Ratio Is Associated with Vascular Access Failure in Hemodialysis Patients

After stenosis of arteriovenous vascular access in hemodialysis patients, platelets play a crucial role in subsequent thrombus formation, leading to access failure. In a previous study, the mean platelet volume (MPV)/platelet count ratio, but not MPV alone, was shown to be an independent predictor of 4-year mortality after myocardial infarction. However, little is known about the potential influence of MPV/platelet count ratio on vascular access patency in hemodialysis patients. A total of 143 patients undergoing routine hemodialysis were recruited between January 2013 and February 2016. Vascular access failure (VAF) was defined as thrombosis or a decrease of greater than 50% of normal vessel diameter, requiring either surgical revision or percutaneous transluminal angioplasty. Cox proportional hazards model analysis ascertained that the change of MPV/platelet count ratio between baseline and 3 months [Δ(MPV/platelet count ratio)_3mo-baseline] had prognostic value for VAF. Additionally, the changes of MPV/platelet count ratio over time were compared in patients with and without VAF by using linear mixed model analysis. Of the 143 patients, 38 (26.6%) were diagnosed with VAF. During a median follow-up of 26.9 months (interquartile range 13.0–36.0 months), Δ(MPV/platelet count ratio)_3mo-baseline significantly increased in patients with VAF compared to that in patients without VAF [11.6 (6.3–19.0) vs. 0.8 (-1.8–4.0), P< 0.001]. In multivariate analysis, Δ(MPV/platelet ratio count)_3mo-baseline was an independent predictor of VAF, after adjusting for age, sex, diabetes, hypertension, coronary artery disease, cerebrovascular disease, vascular access type, the presence of previous VAF, and antiplatelet drug use (hazard ratio, 1.15; 95% confidence interval, 1.10–1.21; P< 0.001). Moreover, a liner mixed model revealed that there was a significant increase of MPV/platelet count ratio over time in patients with VAF compared to those without VAF (P< 0.001). An increase in MPV/platelet count ratio over time was an independent risk factor for VAF. Therefore, continuous monitoring of the MPV/platelet count ratio may be useful to screen the risk of VAF in patients undergoing routine hemodialysis.

Vascular access placement in patients with chronic kidney disease Stages 4 and 5 attending an inner city nephrology clinic: a cohort study and survey of providers

BACKGROUND

The majority of incident hemodialysis (HD) patients initiate dialysis via catheters. We sought to identify factors associated with initiating hemodialysis with a functioning arterio-venous (AV) access.

METHODS

We conducted a retrospective chart review of all adult patients, age >18 years seeing a nephrologist with a diagnosis of CKD stage 4 or 5 during the study period between 06/01/2011 and 08/31/2013 to evaluate the placement of an AV access, initiation of dialysis and we conducted a survey of providers about the process.

RESULTS

The 221 patients (56% female) in the study had median age of 66 years (interquartile range (IQR), 57-75) and were followed for a median of 1.26 years (IQR 0.6-1.68). At study entry, 81%had CKD stage 4 and 19% had CKD stage 5. By the end of study, 48 patients had initiated dialysis. Thirty-four of the patients started dialysis with a catheter (1 failed and 10 maturing AVFs), 9 with an AVF and 5 with an AVG. During the study period, 61 total AV accesses were placed (54 AVF and 7 AVG). A higher urinary protein/ creatinine ratio and a lower eGFR were associated with AV access placement and dialysis initiation. A greater number of nephrology visits were associated with AV access creation but not dialysis initiation. Hospitalizations and hospitalizations with an episode of acute kidney injury (AKI) were strongly associated with dialysis initiation (odds ratio (OR) 13.0 (95% confidence interval (CI) 2.3 to 73.3, p-value = 0.004) and OR 6.6 (95% CI 1.9 to 22.8, p-value = 0.003)).

CONCLUSIONS

More frequent nephrology clinic visits for patients with a recent hospitalization may improve rates of placement of an AV access. A hospitalization with AKI is strongly associated with the need for dialysis initiation. Nephrologists may not be referring the correct patients to get an AV access surgery.

Forty years of shunt surgery at Rigshospitalet, Denmark: a retrospective study comparing past and present rates and causes of revision and infection

OBJECTIVE

The objective of this study is to review our experience of shunt surgery by investigating 40 years of development in terms of rates of revision and infection, shunt survival and risk factors.

DESIGN AND PARTICIPANTS

Medical records and operative reports were reviewed retrospectively for all patients who underwent primary shunt surgery at our department in the years 2010 to 2012. All results were compared with a previous study from our department. A mixed population consisting of 434 patients was included. Adults (≥15 years) accounted for 89.9% of all patients and the mean follow-up time was 1.71 years.

RESULTS

Overall, 42.6% had a revision of which 65.4% fell within 6 months postoperatively. Low age, high-risk diagnoses and less severe brain injury were associated with a higher risk of revision. One and 5-year shunt survival probabilities were 66.2% (61.5-70.9) and 48.0% (41.1-54.9). Within 4 weeks postoperatively, 3.2% had an infection and overall infection rate was 5.5%. Short duration of surgery and the use of antibiotic prophylaxis were associated with a lower risk of infection. The most frequent causes of revision were valve defects (18.4%) and proximal defects or obstructions (15.7%). Compared to the previous study, no convincing improvement was found with regard to the revision rate (42.6% vs 48.3%, p 0.060) or overall infection rate (5.5% vs 7.4%, p 0.261).

CONCLUSIONS

Regardless of changes in patient demographics, techniques and equipment, risk of revision and infection still constitutes a major challenge in shunt surgery. The absence of convincing improvements calls for more studies concerning strategies to reduce complications.

Facility Practice Variation to Help Understand the Effects of Public Policy: Insights from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Recent Centers for Medicare & Medicaid Services policies have used dialysis facility practice variation to develop public ratings and adjust payments. In the Dialysis Facility Compare star rating system (DFC SRS), facility-relative rates of performance-based clinical measures varied nearly two-fold for mortality (standardized mortality ratio; 10th/90th percentiles: 0.71, 1.34) and hospitalization (standardized hospitalization ratio; 10th/90th percentiles: 0.64, 1.37), and nearly four-fold for transfusion (standardized transfusion ratio; 10th/90th percentiles: 0.43, 1.65). Medicare claims data (from July of 2014) demonstrate that facility variation for the proportions of patients on hemodialysis hospitalized (10th/90th percentiles: 27%, 50%) and transfused (10th/90th percentiles: 3%, 17%) within 6 months that far exceeds relatively modest recent overall longitudinal trends. DFC SRS-rated facility variation is also substantial for fistula (10th/90th percentiles: 50%, 78%) and catheter use >90 days (10th/90th percentiles: 3%, 19%). By contrast, DFC SRS-rated facility distributions for adult hemodialysis Kt/V>1.2 (10th/90th percentiles: 84%, 97%) and total serum calcium >10.2 mg/dl (median, 1%; 75th/90th percentiles: 3%, 5%) are quite narrow and may be of questionable value. Likewise, variation in the US Dialysis Outcomes and Practice Patterns Study is over two-fold for facility median serum parathyroid hormone (10th/90th percentiles: 290 pg/ml, 629 pg/ml) and ferritin (10th/90th percentiles: 469 ng/ml, 1143 ng/ml) levels, and facility mean treatment time varies by 30 minutes (10th/90th percentiles: 204 minutes, 234 minutes). Rising serum parathyroid hormone and ferritin levels, and generally short dialysis treatment time, represent areas unchecked by existing policy; both overall trends and facility variation in these values may reflect unintended consequences of policy or reimbursement pressures and therefore raise concern. Additionally, outcomes in the transition period from advanced CKD to dialysis remain poor, and policy initiatives and performance accountability in this area remain insufficient. Innovative models of comprehensive care in advanced CKD and the early dialysis period which are more amenable to policy oversight are needed. In summary, facility variation is typically larger than prevailing longitudinal trends, and should not be overlooked. The combination of nationally representative observational databases (e.g., the Dialysis Outcomes and Practice Patterns Study) and ESRD registries can provide policy makers with additional tools to evaluate facility variation, develop policies, and monitor unintended effects.

The Healthy People 2020 Objectives for Kidney Disease: How Far Have We Come, and Where Do We Need to Go?

The Healthy People 2020 initiative established goals for patients with CKD and ESRD. We assessed United States progress toward some of these key goals. Using data from the Centers for Medicare and Medicaid Services ESRD database, we created yearly cohorts of patients on incident and prevalent dialysis from 2000 to 2013. Change in event rate or proportion change over the study years was modeled using Poisson regression with adjustment for age, race, sex, and primary cause of ESRD. For all-cause mortality in prevalent patients, Healthy People 2020 sought approximately 0.8% relative annual improvement; actual improvement was 2.7%. Improvement was greatest for patients ages 18-44 years old (3.8%; P<0.01 versus 2.8% for ages 65-74 years old) and 2.3% even for patients ages ≥75 years old. For mortality in incident patients, the relative annual decrease was 2.1% overall, a twofold improvement over the goal; mortality decreased nearly twice as much in black as in white patients (3.2% versus 1.8%; P<0.001). Geographic variation was substantial; the relative annual decrease was 0.6% in the Midwest and more than fourfold greater (2.7%) in the South. Cardiovascular mortality in prevalent patients decreased dramatically at 5.0% per year, far exceeding the annual goal of approximately 0.8%; the decrease was greatest in patients ages ≥75 years old (5.5%; P<0.001 versus ages 65-74 years old; 5.1%). The relative annual increase in percentages of patients with a fistula at dialysis initiation was 2.4%, roughly three times the goal; the increase was greater for black than white patients (3.2% versus 2.3%; P<0.01). Adjusted regional differences varied greater than twofold: 2.0% for the South versus 4.1% for the Midwest. Thus, although gains have been substantial, not all groups have benefitted equally. Goal development for Healthy People 2030 should consider changes in goal paradigms, such as tailoring by geographic region and incorporating patient-centered goals.

Association of Peritonitis with Hemodialysis Catheter Dependence after Modality Switch

BACKGROUND AND OBJECTIVES

Few studies have evaluated vascular access use after transition from peritoneal dialysis to hemodialysis. Our study characterizes vascular access use after switch to hemodialysis and its effect on patient mortality and evaluates whether a peritonitis event preceding the switch was associated with the timing of permanent vascular access placement and use.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The US Renal Data System data were used to evaluate the establishment of a permanent vascular access in 1165 incident Medicare-insured adult patients on dialysis who initiated peritoneal dialysis between July 1, 2010 and June 30, 2011 and switched to hemodialysis within 1 year.

RESULTS

The proportions of patients using a hemodialysis catheter were 85% (744 of 879), 76% (513 of 671), and 51% (298 of 582) at 30, 90, and 180 days, respectively, after the switch from peritoneal dialysis to hemodialysis. Patients who switched from peritoneal dialysis to hemodialysis with a previous peritonitis episode were more likely to dialyze with a catheter at 30 days (90% [379 of 421] versus 80% [365 of 458]; P=0.03), 90 days (82% [275 of 334] versus 71% [238 of 337]; P=0.03), and 180 days (57% [166 of 289] versus 45% [132 of 293]; P=0.04) after the switch and less likely to dialyze with an arteriovenous fistula at 30 days (8% [32 of 421] versus 16% [73 of 458]; P=0.01), 90 days (13% [42 of 334] versus 23% [76 of 337]; P=0.03), and 180 days (31% [91 of 289] versus 43% [126 of 293]; P=0.04). Patients using a permanent vascular access 180 days after switching from peritoneal dialysis to hemodialysis had better adjusted survival during the ensuing year than those using a catheter (hazard ratio, 0.66; 95% confidence interval, 0.44 to 1.00; P=0.05).

CONCLUSIONS

Among patients who switch from peritoneal dialysis to hemodialysis, prior peritonitis is associated with a higher rate of persistent hemodialysis catheter use, which in turn, is associated with lower patient survival. Studies addressing vascular access planning and implementation are needed in this group of patients.

Predictors of Initiation for Predialysis Arteriovenous Fistula

BACKGROUND AND OBJECTIVES

The optimal timing of predialysis arteriovenous fistula surgery remains uncertain. We evaluated factors associated with hemodialysis initiation in patients undergoing predialysis arteriovenous fistula surgery and derived a model to predict future initiation of dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study retrospectively identified 308 patients undergoing predialysis arteriovenous fistula creation at a large medical center in 2006-2012 to determine whether they initiated hemodialysis. Multiple variable logistic regression analyzed which demographic and clinical factors predicted initiation of dialysis within 2 years of arteriovenous fistula surgery. A receiver operating characteristic area under the curve was used to quantify the predictive value of preoperative factors on the likelihood of initiating hemodialysis within 2 years.

RESULTS

Overall, hemodialysis was initiated within 6 months, 1 year, and 2 years in 119 (39%), 175 (57%), and 211 (68%) patients, respectively. Using multiple variable logistic regression, four factors were associated with hemodialysis initiation at 2 years: eGFR at access surgery (odds ratio, 0.45; 95% confidence interval, 0.31 to 0.64 per 5 ml/min per 1.73 m2; P<0.001), diabetes (odds ratio, 2.51; 95% confidence interval, 1.22 to 5.15; P=0.003), GFR trajectory (odds ratio, 1.54; 95% confidence interval, 1.09 to 2.17 per 3 ml/min per 1.73 m2 per year; P=0.01), and spot urine protein-to-creatinine ratio (odds ratio, 1.39; 95% confidence interval, 1.14 to 1.71 per 1 U; P<0.001). eGFR alone had a moderate predictive value for dialysis initiation (area under the curve =0.69; 95% confidence interval, 0.63 to 0.76; P<0.001), whereas the full model had a higher predictive value (area under the curve =0.83; 95% confidence interval, 0.77 to 0.88; P<0.001).

CONCLUSIONS

The likelihood of initiating hemodialysis within 2 years of predialysis arteriovenous fistula surgery is associated with eGFR at access surgery, diabetes, GFR trajectory, and magnitude of proteinuria. The combined use of all four variables improves the ability to predict future hemodialysis compared with the use of eGFR alone.

Peripherally Inserted Central Catheters and Hemodialysis Outcomes

BACKGROUND AND OBJECTIVES

Use of peripherally inserted central catheters has expanded rapidly, but the consequences for patients who eventually require hemodialysis are undefined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our national, population-based analysis included 33,918 adult Medicare beneficiaries from the US Renal Data System who initiated hemodialysis with central venous catheters as their sole vascular access in 2010 and 2011. We used linked Medicare claims to identify peripherally inserted central catheter exposures and evaluate the associations of peripherally inserted central catheter placement with transition to working arteriovenous fistulas or grafts and patient survival using a Cox model with time-dependent variables.

RESULTS

Among 33,918 individuals initiating hemodialysis with a catheter as sole access, 12.6% had received at least one peripherally inserted central catheter. Median follow-up was 404 days (interquartile range, 103-680 days). Among 6487 peripherally inserted central catheters placed, 3435 (53%) were placed within the 2 years before hemodialysis initiation, and 3052 (47%) were placed afterward. Multiple peripherally inserted central catheters were placed in 30% of patients exposed to peripherally inserted central catheters. Recipients of peripherally inserted central catheters were more likely to be women and have comorbid diagnoses and less likely to have received predialysis nephrology care. After adjustment for clinical and demographic factors, peripherally inserted central catheters placed before or after hemodialysis initiation were independently associated with lower likelihoods of transition to any working fistula or graft (hazard ratio for prehemodialysis peripherally inserted central catheter, 0.85; 95% confidence interval, 0.79 to 0.91; hazard ratio for posthemodialysis peripherally inserted central catheter, 0.81; 95% confidence interval, 0.73 to 0.89).

CONCLUSIONS

Peripherally inserted central catheter placement was common and associated with adverse vascular access outcomes. Recognition of potential long-term adverse consequences of peripherally inserted central catheters is essential for clinicians caring for patients with CKD.

Comparison of Outcomes with Arteriovenous Fistula and Arteriovenous Graft for Vascular Access in Hemodialysis: A Prospective Cohort Study

BACKGROUND

Poor vessel quality and limited life expectancy in the elderly may make arteriovenous fistula (AVF) less ideal than arteriovenous graft (AVG) or catheter for vascular access (VA) in hemodialysis (HD).

METHODS

A total of 946 adult incident HD patients from clinical research center registry for end-stage renal disease prospective cohort in South Korea were analyzed for outcomes with AVF and AVG.

RESULTS

Overall, AVF was associated with better patient survival only in male (p < 0.001) and diabetic (p = 0.004) patients, although it was superior to AVG in access patency, regardless of diabetes mellitus status and gender. AVG (vs. AVF; hazard ratio (HR) 2.282; 95% CI 1.071-4.861; p = 0.032) was associated with poor patient survival. In elderly patients (≥65 years), AVF was associated with survival benefit only in male (p < 0.001) and diabetic (p = 0.04) patients, and with better access patency only in female (p = 0.05) and diabetic (p = 0.04) patients. AVG (vs. AVF; HR 3.158; 95% CI 1.080-9.238; p = 0.036) was associated with poor patient survival. In septuagenarian patients, AVF was associated only with survival benefit (p = 0.01) and there was no advantage in access patency (p = 0.12). However, AVF was superior to AVG in both access patency (p = 0.001) and patient survival (p = 0.03) even with propensity matching.

CONCLUSION

AVF is the more desirable VA and its survival benefits warrant its consideration in septuagenarian patients although a prolonged life expectancy is essential to realize the potential benefits of AVF.

Impact of Poverty and Health Care Insurance on Arteriovenous Fistula Use among Incident Hemodialysis Patients

BACKGROUND

The impact of socioeconomic factors on arteriovenous fistula (AVF) creation in hemodialysis (HD) patients is not well understood. We assessed the association of area and individual-level indicators of poverty and health care insurance on AVF use among incident end-stage renal disease (ESRD) patients initiated on HD.

METHODS

In this retrospective cohort study using the United States Renal Data System database, we identified 669,206 patients initiated on maintenance HD from January 1, 2007 through December 31, 2012. We assessed the Medicare-Medicaid dual-eligibility status as an indicator of individual-level poverty and ZIP code-level median household income (MHI) data obtained from the 2010 United States Census. We conducted logistic regression of AVF use at start of dialysis as the outcome variable.

RESULTS

The proportions of dual-eligible and non-dual-eligible patients who initiated HD with an AVF were 12.53 and 16.17%, respectively (p<0.001). Dual eligibility was associated with significantly lower likelihood of AVF use upon initiation of HD (adjusted odds ratio (aOR) 0.91; 95% CI 0.90-0.93). Patients in the lowest area-level MHI quintile had an aOR of 0.97 (95% CI 0.95-0.99) compared to those in higher quintile levels. However, dual eligibility and area-level MHI were not significant in patients with Veterans Affairs (VA) coverage.

CONCLUSIONS

Individual- and area-level measures of poverty were independently associated with a lower likelihood of AVF use at the start of HD, the only exception being patients with VA health care benefits. Efforts to improve incident AVF use may require focusing on pre-ESRD care to be successful.

Preoperative vascular access evaluation for haemodialysis patients

BACKGROUND

Haemodialysis treatment requires reliable vascular access. Optimal access is provided via functional arteriovenous fistula (fistula), which compared with other forms of vascular access, provides superior long-term patency, requires few interventions, has low thrombosis and infection rates and cost. However, it has been estimated that between 20% and 60% of fistulas never mature sufficiently to enable haemodialysis treatment. Mapping blood vessels using imaging technologies before surgery may identify vessels that are most suitable for fistula creation.

OBJECTIVES

We compared the effect of conducting routine radiological imaging evaluation for vascular access creation preoperatively with standard care without routine preoperative vessel imaging on fistula creation and use.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 14 April 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that enrolled adult participants (aged ≥ 18 years) with chronic or end-stage kidney disease (ESKD) who needed fistulas (both before dialysis and after dialysis initiation) that compared fistula maturation rates relating to use of imaging technologies to map blood vessels before fistula surgery with standard care (no imaging).

DATA COLLECTION AND ANALYSIS

Two authors assessed study quality and extracted data. Dichotomous outcomes, including fistula creation, maturation and need for catheters at dialysis initiation, were expressed as risk ratios (RR) with 95% confidence intervals (CI). Continuous outcomes, such as numbers of interventions required to maintain patency, were expressed as mean differences (MD). We used the random-effects model to measure mean effects.

MAIN RESULTS

Four studies enrolling 450 participants met our inclusion criteria. Overall risk of bias was judged to be low in one study, unclear in two, and high in one.There was no significant differences in the number of fistulas that were successfully created (4 studies, 433 patients: RR 1.06, 95% CI 0.95 to 1.28; I² = 76%); the number of fistulas that matured at six months (3 studies, 356 participants: RR 1.11, 95% CI 0.98 to 1.25; I² = 0%); number of fistulas that were used successfully for dialysis (2 studies, 286 participants: RR 1.12, 95% CI 0.99 to 1.28; I² = 0%); the number of patients initiating dialysis with a catheter (1 study, 214 patients: RR 0.66, 95% CI 0.42 to 1.04); and in the rate of interventions required to maintain patency (1 study, 70 patients: MD 14.70 interventions/1000 patient-days, 95% CI -7.51 to 36.91) between the use of preoperative imaging technologies compared with standard care (no imaging).

AUTHORS' CONCLUSIONS

Based on four small studies, preoperative vessel imaging did not improve fistula outcomes compared with standard care. Adequately powered prospective studies are required to fully answer this question.

Vascular access creation before hemodialysis initiation and use: a population-based cohort study

BACKGROUND AND OBJECTIVES

In Canada, approximately 17% of patients use an arteriovenous access (fistula or arteriovenous graft) at commencement of hemodialysis, despite guideline recommendations promoting its timely creation and use. It is unclear if this low pattern of use is attributable to the lack of surgical creation or a high nonuse rate.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using large health care databases in Ontario, Canada, a population-based cohort of adult patients (≥18 years old) who initiated hemodialysis as their first form of RRT between 2001 and 2010 was studied. The aims were to (1) estimate the proportion of patients who had an arteriovenous access created before starting hemodialysis and the proportion who successfully used it at hemodialysis start, (2) test for secular trends in arteriovenous access creation, and (3) estimate the effect of late nephrology referral and patient characteristics on arteriovenous access creation.

RESULTS

There were 17,183 patients on incident hemodialysis. The mean age was 65.8 years, 60% were men, and 40% were referred late to a nephrologist; 27% of patients (4556 of 17,183) had one or more arteriovenous accesses created, and the median time between arteriovenous access creation and hemodialysis start was 184 days. When late referrals were excluded, 39% of patients (4007 of 10,291) had one or more arteriovenous accesses created, and 27% of patients (2724 of 10,291) used the arteriovenous access. Since 2001, there has been a decline in arteriovenous access creation before hemodialysis initiation. Women, higher numbers of comorbidities, and rural residence were consistently associated with lower rates of arteriovenous access creation. These results persisted even after removing patients with <6 months nephrology care or who had AKI 6 months before starting hemodialysis.

CONCLUSIONS

In Canada, arteriovenous access creation before hemodialysis initiation is low, even among patients followed by a nephrologist. Better understanding of the barriers and influencers of arteriovenous access creation is needed to inform both clinical care and guidelines.

Predictors of sustained arteriovenous access use for haemodialysis

BACKGROUND

Guidelines encourage early arteriovenous (AV) fistula (AVF) planning for haemodialysis (HD). The aim of this study was to estimate the likelihood of sustained AV access use taking into account age, sex, comorbidity, anatomical site of first AVF and, for pre-dialysis patients, eGFR and proteinuria.

METHODS

1,092 patients attending our centre who had AVF as their first AV access procedure between January 1, 2000 and August 23, 2012 were identified from the electronic patient record. The primary end-point was time to first sustained AV access use, defined as use of any AV access for a minimum of 30 consecutive HD sessions.

RESULTS

52.9% (n = 578) of the patients ultimately achieved sustained AV access use. The main reasons for AV access non-use were AVF failure to mature and death. The 3-year Kaplan-Meier probability of sustained AV access use was 68.8% for those not on renal replacement therapy (RRT) (n = 688) and 74.2% for those already on RRT (n = 404) at the time of first AVF. By multivariate analysis in patients not on RRT, male sex (HR 2.22; p < 0.001), uPCR (HR 1.03; p = 0.03) and eGFR (hazard ratio, HR 0.85; p < 0.001) were independent predictors of AV access use. In patients already on RRT, age (HR 0.98; p < 0.001) and peripheral vascular disease (HR 0.48; p = 0.02) were independent predictors of AV access use.

CONCLUSION

Our data suggest that refinement of the current guideline for timing of AV access creation in planning RRT is justified to take into account individual factors that contribute to the likelihood of technical success and clinical need.

Prevalence of pre-end-stage renal disease care and associated outcomes among urban, micropolitan, and rural dialysis patients

BACKGROUND/AIMS

Pre-end-stage renal disease (ESRD) care is associated with improved outcomes among patients receiving dialysis. It is unknown what proportion of US micropolitan and rural dialysis patients receive pre-ESRD care and benefit from such care when compared to urban.

METHODS

A retrospective cohort study was performed using data from the US Renal Data System. Patients ≥18 years old who initiated dialysis in 2006 and 2007 were classified as rural, micropolitan or urban and the prevalence of pre-ESRD care (early nephrology care >6 months, permanent vascular access, -dietary education) was determined using the medical evidence report. The association of pre-ESRD care with dialysis mortality and transplantation was assessed using Cox regression with stratification for geographic residence.

RESULTS

Of 204,463 dialysis patients, 80% were urban, 10.2% were micropolitan and 9.8% were rural. Overall attainment of pre-ESRD care was poor. After adjustment, there were no significant geographic differences in attainment of early nephrology care or permanent dialysis access. Receiving care reduced all-cause mortality and increased the likelihood of transplantation to a similar degree regardless of geographic residence. Both micropolitan and rural patients received less dietary education (relative risk = 0.80, 95% CI = 0.76-0.84 and relative risk = 0.85, 95% CI = 0.80-0.89, respectively).

CONCLUSION

Among patients who receive dialysis, the prevalence of early nephrology care and permanent dialysis access is poor and does not vary by geographic residence. Micropolitan and rural patients receive less dietary education despite an observed mortality benefit, suggesting that barriers may exist to quality dietary care in more remote locations.

[Evolution of ultrasonic indices of the heart and arteriovenous fistulas in patients on chronic haemodialysis]

The authors assessed the ultrasonic evolution of haemodynamics of arteriovenous fistulas (AVFs), cardiohaemodynamics, and the dimensions of the heart chambers in a total of thirty-five patients presenting with terminal chronic renal insufficiency (TCRI) and being on chronic haemodialysis (CHD). A further thirteen patients without TCRI composed the control group. The TCRI patients were subdivided into two groups: Group One (n=20) with a distal variant of the Cimino-type AVF, 21 vascular accesses, and Group Two (n=15) with a proximal variant of AFV, 16 accesses using a synthetic vascular prosthesis (SVP). The terms of follow up of the TCRI patients were as follows: day 12, months 1, 3, 6 and 12 after creating the AVF. 12 days after creating the AVF there were no differences in the parameters of cardiohaemodynamics and the dimensions of the cardiac chambers between Group I and II. As compared with the control, the both groups of the patients with TCRI at these terms demonstrated increased sizes of the left ventricle (LV). The dynamic follow up during the subsequent periods showed that Group One and Group Two patients had no statistically significant differences in the parameters studied, however, patients of the both study groups were found to have a trend toward increased dimensions of the right chambers of the heart, not exceeding the limits of the norm of these indices. The volumetric velocity of the blood flow (BFVV) through the Cimino-type AVF during 12 months had a tendency towards a graduate growth up to 800 ml/min, whereas the proximal fistulas were characterized by stable indices of the BFVV at a level of 900 ml/min. The revealed alterations in the right chambers of the heart after creating the AVF required no surgical correction of the volumetric blood flow through the AVF during the follow up period up to 12 months.

Effects of starting hemodialysis with an arteriovenous fistula or central venous catheter compared with peritoneal dialysis: a retrospective cohort study

BACKGROUND

Although several studies have demonstrated early survival advantages with peritoneal dialysis (PD) over hemodialysis (HD), the reason for the excess mortality observed among incident HD patients remains to be established, to our knowledge. This study explores the relationship between mortality and dialysis modality, focusing on the role of HD vascular access type at the time of dialysis initiation.

METHODS

A retrospective cohort study was performed among local adult chronic kidney disease patients who consecutively initiated PD and HD with a tunneled cuffed venous catheter (HD-TCC) or a functional arteriovenous fistula (HD-AVF) in our institution in the year 2008. A total of 152 patients were included in the final analysis (HD-AVF, n = 59; HD-TCC, n = 51; PD, n = 42). All cause and dialysis access-related morbidity/mortality were evaluated at one year. Univariate and multivariate analysis were used to compare the survival of PD patients with those who initiated HD with an AVF or with a TCC.

RESULTS

Compared with PD patients, both HD-AVF and HD-TCC patients were more likely to be older (p<0.001) and to have a higher frequency of diabetes mellitus (p = 0.017) and cardiovascular disease (p = 0.020). Overall, HD-TCC patients were more likely to have clinical visits (p = 0.069), emergency room visits (p<0.001) and hospital admissions (p<0.001). At the end of follow-up, HD-TCC patients had a higher rate of dialysis access-related complications (1.53 vs. 0.93 vs. 0.64, per patient-year; p<0.001) and hospitalizations (0.47 vs. 0.07 vs. 0.14, per patient-year; p = 0.034) than HD-AVF and PD patients, respectively. The survival rates at one year were 96.6%, 74.5% and 97.6% for HD-AVF, HD-TCC and PD groups, respectively (p<0.001). In multivariate analysis, HD-TCC use at the time of dialysis initiation was the important factor associated with death (HR 16.128, 95%CI [1.431-181.778], p = 0.024).

CONCLUSION

Our results suggest that HD vascular access type at the time of renal replacement therapy initiation is an important modifier of the relationship between dialysis modality and survival among incident dialysis patients.

Improving the fistula rate: the northwest renal network experience

In November 2010, Northwest Renal Network was the first of the 18 ESRD Networks to reach the Fistula First goal of greater than 66% prevalent hemodialysis patients using an arteriovenous fistula (AVF). The network has sustained that goal over time and as of August 2011, has achieved an AVF rate of 67.7%. The Northwest Renal Network has been successfully motivating facilities to embrace change using thorough root cause analyses and targeted quality improvement projects throughout the Network's five-state region.

Epidemiology of hemodialysis vascular access in the United States

Reemergence of the importance of vascular access in the care of the chronic hemodialysis patient has gained prominence due to renewed interest in clinical outcomes and evidence-based interventions. Further fueled by anticipated regulatory changes in the reimbursement for dialysis care in the United States by 2011 and beyond, the drive to improve quality of care for hemodialysis patients has identified vascular access issues as a key contributor to outcomes. Focus has shifted from simply providing any hemodialysis vascular access to a strong preference for the use of native arteriovenous fistulas and subsequently to a need for reducing exposure to central venous catheters. Combined, these goals have forced a reevaluation of the role of arteriovenous grafts. The context and events associated with the evolution of thinking on these issues as well as available data supporting them are discussed. The key leadership role of nephrologists is emphasized along with a summary of problems and proposed solutions.

Bedside screening for fistula stenosis should be tailored to the site of the arteriovenous anastomosis

BACKGROUND AND OBJECTIVES

Given different sites of stenosis and access blood flow rates (Qa), the criteria for diagnosing fistula stenosis might vary according to anastomotic site. To test this, we analyzed the database of a prospective blinded study seeking an optimal bedside screening program for fistula stenosis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Several methods used during dialysis (physical examination [PE], dynamic and derived static venous pressure [VAPR], dialysis blood pump flow/arterial pressure ratio, and Qa measurement) to diagnose angiographically-proven >50% stenosis were assessed in an unselected population of hemodialysis patients with mature fistulae (43 at the wrist [distal fistulae], 76 at mid-forearm or the elbow [proximal fistulae]).

RESULTS

Prevalence of inflow stenosis was uninfluenced by anastomotic site, whereas outflow stenoses were more prevalent in proximal fistulae. The best test for inflow stenosis was Qa <650 ml/min in distal fistulae and a combination of a positive PE and Qa <900 ml/m in proximal fistulae. In proximal fistulae, PE and VAPR >0.5 were both equally highly diagnostic of outflow stenosis. Tailoring choice of test to site of the anastomosis may also contain the screening-associated workload, by reducing the need to perform PE and measure VAPR, compared with a screening approach regardless of the access location.

CONCLUSIONS

Our study shows that an effective bedside screening program with ≥85% accuracy for fistula stenosis can be tailored to the site of the anastomosis, Qa being the tool of choice for the wrist, and PE alone or combined with Qa and VAPR measurements for more proximally-located accesses.

A three-step approach to conversion of prevalent catheter-dependent hemodialysis patients to arteriovenous access

BACKGROUND AND OBJECTIVES

Prevalent central venous catheter (CVC) rates among hemodialysis (HD) patients in Canada remain high. In October 2006, we implemented a three-step multidisciplinary quality improvement project in our in-centre HD unit. The primary objective was to convert 50% of suitable patients to arteriovenous fistulas (AVFs) or arteriovenous grafts (AVGs). DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENT: We undertook a case-crossover evaluation of the efficacy of a three-step conversion strategy. In step one, all medically suitable in-centre HD patients were assessed for arteriovenous (AV) access creation. In step two, patients were scheduled for preoperative vascular mapping and referred to the vascular surgeon. In step three, patients who refused conversion were asked to sign a waiver indicating that their decision to continue with a CVC was against medical advice.

RESULTS

At the start of the project in October 2006, there were a total of 284 patients on HD in our in-centre unit and 108 patients were catheter-dependent (38%). Of these, 53 patients were deemed suitable for conversion from a CVC to AVF or AVG; 26/53 (49%) patients agreed to conversion and 27/53 (51%) refused conversion. For the patients in the conversion group, 63% had been followed in chronic kidney disease (CKD) clinic and 37% initiated dialysis acutely; compared to 57% and 43% respectively in the refusal group. The difference was not statistically significant (p = 0.62 by Chi-square test), suggesting that there may be other factors affecting a patient's decision other than predialysis nephrology care. Of interest, 19/27 (70%) of patients who refused conversion signed the waiver and 8/27 (30%) refused to sign the waiver. None of the patients, when confronted with the waiver, agreed to conversion. Based on analysis of the main findings from our study, patients were most concerned about insertion of needles, pain and the appearance of their AV accesses. While 22 patients have successfully converted, resulting in a conversion rate of 41.5%, the percentage of catheter-dependent patients increased from 38% to 46% during the project period. Factors that likely contribute to the increase in point-prevalence CVC rates during the project period include a high rate of patient refusal, a high rate of patients deemed to be medically unsuitable, AV access failure during the project period, and most common was a failure to create AV access among incident HD patients who were followed in our centre through the late stages of chronic kidney disease (CKD). Successful conversion was defined as removal of CVC and use ofAVaccess for HD at the end of the study period (December, 2010).

CONCLUSION

Long-term CVC use in Canada and the unwillingness of medically suitable patients to convert to more optimal forms of vascular access are linked problems with potentially grave consequences. We need to develop a better understanding of the patients' perspective and possible psychological factors affecting patients' decisions if we are to have an impact on the high CVC use of Canadian prevalent HD patients.

An arteriovenous fistula (AVF) functionality quality improvement tracking tool--developed and implemented to improve newly placed AVF utilization rates and patient outcomes

The authors developed a reporting tool to assist hemodialysis clinicians to track new arteriovenous fistulas (AVFs), their maturation, and use. The tool identifies impediments to timely use (6 weeks/42 days) of AVFs. The use of this tool in nine dialysis units with high gaps between AVF placement and usage reduced the gap from 19.5% to 13.5% and reflected a reduction in the percentage of AVFs in place but not in use from 31.4% to 23.2%.

Who should be referred for a fistula? A survey of nephrologists

BACKGROUND

There is marked variation in the use of the arteriovenous fistula (AVF) across programmes, regions and countries not explained by differences in patient demographics or comorbidities. The lack of clear criteria of who should or should not get a fistula may contribute to this, as well as barriers to creating AVFs.

METHODS

We conducted a survey of Canadian and American nephrologists to assess the patient variables considered to determine the timing and type of access requested. Perceived barriers and absolute contraindications to access were also collected.

RESULTS

An immediate referral for a fistula was more highly preferred when patients are <65 years old, have minimal comorbidities or have no history of failed accesses. In older patients, and in those with increased comorbidities or a previously failed fistula, US nephrologists selected arteriovenous grafts as an alternative to the fistula, while Canadian nephrologists selected primarily catheters. Referral for vascular mapping was more common in the USA than in Canada. Gender did not influence the timing or the type of access. Perceived barriers to establishing a mature fistula included patient refusal for creation (77%) or cannulation (58%), delay in decision regarding dialysis modality (71%), wait time for surgical creation (55%) and high failure-to-mature rate (52%). We found that 27% of Canadian and 43% of American nephrologists indicated no absolute contraindications for permanent vascular access.

CONCLUSIONS

This study demonstrated marked variability in timing and criteria used to select patients for referral for a vascular access between nephrologists practicing within Canada and the USA. Establishing minimal eligibility criteria for fistulae is an important area of future research.

Racial and gender differences in arteriovenous fistula use among incident hemodialysis patients

BACKGROUND

Arteriovenous fistula (AVF) use is reported to differ among racial and gender groups. We sought to identify risk factors associated with incident AVF and whether racial and gender differences in AVF use persist after controlling for these factors.

METHODS

We evaluated 28,712 incident adult hemodialysis patients (age ≥ 18) from five ESRD networks starting dialysis between June 1, 2005 and May 31, 2006. Data were obtained from the Center for Medicaid and Medicare Services 2728 form.

RESULTS

Incident AVF use was reported for 11% of black and 12% of white patients [OR = 0.89 (95% CI: 0.83, 0.96)], and for 9% of females and 13% of males [OR = 0.66 (0.62-0.71)]. After adjusting for facility clustering, blacks were as likely as whites to use an AVF [OR = 1.00 (0.92-1.09)], while gender differences persisted [OR = 0.64 (0.59-0.69)]. Compared to patients with no renal care prior to dialysis initiation, incident AVF use was 16-fold greater among those with ≥ 12 months of nephrology care [OR = 15.99 (13.25-19.29)], 9-fold greater among those with 6-12 months of care [OR = 9.00 (7.45-10.88)] and 7-fold greater among those with at least 6 months of care [OR = 7.13 (5.73-8.88)].

CONCLUSION

Racial, but not gender, differences in incident AVF use were eliminated after accounting for clustering within facilities.

Fistula First: myth vs. fact

It is estimated that there are fewer than one million patients with Stages 4 and 5 CKD not on dialysis. Most of these patients have regular encounters with the health care system because of diabetes, hypertension, and other diseases of aging. Many of these patients are not under the ongoing care of a nephrologist, but could be if the appropriate triggers for nephrology referral are established at the system level. Even among patients who have been cared for by a nephrologist for >12 months prior to the onset of dialysis, the incident AVF rate is only around 25%. This is an embarrassingly low rate and reflects an opportunity for the nephrologist to emerge as a leader to drive the system changes that will promote timely referral and AVF placement. A doubling of the incident AVF rate to 50%, achievable with effective system change, is the best path to reach a prevalent AVF rate of 66%.

Hemodialysis vascular access options in pediatrics: considerations for patients and practitioners

Recent data indicate that the incidence of end-stage renal disease (ESRD) in pediatric patients (age 0-19 years) has increased over the past two decades. Similarly, the prevalence of ESRD has increased threefold over the same period. Hemodialysis (HD) continues to be the most frequently utilized modality for renal replacement therapy in incident pediatric ESRD patients. The number of children on HD exceeded the sum total of those on peritoneal dialysis and those undergoing pre-emptive renal transplantation. Choosing the best vascular access option for pediatric HD patients remains challenging. Despite a national initiative for fistula first in the adult hemodialysis population, the pediatric nephrology community in the United States of America utilizes central venous catheters as the primary dialysis access for most patients. Vascular access management requires proper advance planning to assure that the best permanent access is placed, seamless communication involving a multidisciplinary team of nephrologists, nurses, surgeons, and interventional radiologists, and ongoing monitoring to ensure a long life of use. It is imperative that practitioners have a long-term vision to decrease morbidity in this unique patient population. This article reviews the various types of pediatric vascular accesses used worldwide and the benefits and disadvantages of these various forms of access.

Balancing 'fistula first' with a 'catheter last' strategy

Endovascular treatment, in general, is a safe and effective method to assist a fistula to maturation, although this does not mean that surgical revision is not better in some patients. An experienced interventionalist should be able to discern the most appropriate treatment modality based upon physical exam, duplex ultrasound, and/ or fistulogram. The care of a hemodialysis patient is truly a team endeavor, including the primary care physician, nephrologists, dialysis nurses and coordinators, and the interventionalists. Each must be aware that options exist to assist many slowly or non-maturing fistulas in order to establish a usable, functional fistula as soon as possible to limit the frequent complications associated with tunneled catheters. Even diffusely small veins are not beyond the reach of therapy as evidenced with the BAM procedure. Early evaluation following fistula placement (three to four weeks) with quick referral to an experienced interventionalist is crucial. There is emerging data suggesting that there is no negative effect on patency with early cannulation of fistulas, even as soon as one month. Perhaps in the near future we might see an even greater impact on the prevalence of tunneled catheters with the emergence of earlier cannulation of fistulas, along with more aggressive intervention to slowly maturing fistulas, such as the BAM procedure. As experience with the BAM procedure grows, there may be a role for BAM in patients with a suboptimal vein on preoperative vein mapping (< 2.5 mm). These patients, who traditionally would have received a prosthetic graft, might be candidates for fistula placement followed by a preplanned BAM, initiated within weeks of the initial placement. The cost effectiveness and utility of such a strategy is unstudied and would be a good subject for future trials.