The 2006 Kidney Disease Outcomes Quality Initiative (KDOQI) guideline recommended a “fistula first” approach to vascular access creation in patients with kidney failure. When the 2019 KDOQI guideline was released, it was a welcome update, promoting more selective vascular access placement with the tenet “the right access in the right patient at the right time.” Contemporary trends and prospective data support the more nuanced strategy, including findings from a study published recently in the Journal of the American Society of Nephrology.1
Michael Allon, MD, and colleagues at the University of Alabama at Birmingham prospectively observed a more selective approach to vascular access placement among patients at their institution who initiated hemodialysis with a central venous catheter (CVC) and then received either an arteriovenous fistula (AVF) or arteriovenous graft (AVG). They compared 2 periods. In period 1 (2004-2012), the strategy was to maximize AVF creation (408 patients). In period 2 (2013-2019), the strategy was to opt for an AVG if AVF failure was deemed to be likely (284 patients).
AVG placement was significantly more common in the more selective period 2 (41%) compared with period 1 (28%), the investigators reported. In period 1, the AVF group had a significantly higher rate of access procedures compared with the AVG group (248 vs 217 per 100 patient-years). In period 2, access procedures were less likely in the AVF group (185 vs 236 per 100 patient-years, respectively).
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Median annual access management costs were significantly higher among AVF patients ($10,642) versus AVG patients ($6810) in period 1 but significantly decreased for AVF patients in period 2 ($5481 versus $8253, respectively).
Catheter dependence was 3-fold higher in the AVF versus AVG group in period 1 (23.3 vs 8.1 catheter-years per 100 patient-years, respectively), but the gap narrowed in period 2 (20.8 vs 16.0 catheter-years per 100 patient-years, respectively).
Overall, the median annual cost associated with access management was significantly lower in period 2 with selective vascular access placement ($6757) than in period 1 with a fistula-first approach ($9781).
“Our study demonstrates that if you give clinicians leeway in determining the optimal access for each patient, there is a large benefit in terms of overall reduction in the burden of access procedures and access costs,” Dr Allon and colleagues concluded. “At our academic center, a relatively modest increase in AVG placement, from 28 to 41%, resulted in substantial benefit in terms of the frequency and cost of vascular access management.”
In an accompanying editorial3, Karl A. Nath, MBChB, of Mayo Clinic in Rochester, Minnesota, lauded this study. “The present and previous findings of Allon and colleagues are landmark contributions because they provide requisite and persuasive data that bring balance and wisdom to discussions and decision-making regarding the creation of an AVF or an AVG.”
Dr Nath emphasized patient characteristics suitable for AVF. He noted that initial AVF placement is reasonable in younger patients and older patients who are physiologically young because they can withstand the “exacting” vascular adaptations and requirements for AVF maturation. However, he questioned whether AVF should still be favored over the AVG in older patients with diminished life expectancy, cardiovascular comorbidities, geriatric syndromes, and other risks for AVF failure – which represents a substantial proportion of the population with kidney failure.
US Vascular Access Trends
In a separate study published in JAMA Network Open,2 Dr Allon and colleagues examined contemporary vascular access trends using US Renal Data System information gathered from 639,883 patients initiating hemodialysis from 2015 to 2020. AVF use at dialysis initiation (including CVC use during AVF maturation) decreased from 17% in 2015 to 14% in 2020. Predialysis AVF placement decreased from 34% to 25% over the same period. The AVF maturation rate, however, appeared to increase. The proportion of patients with predialysis AVF placement using their AVF at dialysis initiation increased from 51% to 55%.
CVC use at dialysis initiation increased from 61% in 2015 to 71% in 2020. AVG use remained stable at 3%.
The COVID-19 pandemic in 2020 was significantly associated with 29% decreased odds of initiating dialysis with an AVF and 72% increased odds for initiation with a CVC, compared with the year 2015, the investigators reported.
Predialysis nephrology care increased from 76% of patients in 2015 to 82% of patients in 2020. Nephrology care for more than 12 months before dialysis initiation was associated with the highest rate of AVF use and the lowest rate of CVC use throughout the 6-year period.
“The decrease in AVF use may be the inadvertent outcome of the more nuanced, patient-centered 2019 vascular access guidelines, which emphasize selection of the access that is most suitable for each patient,” Dr Allon’s team wrote.
Patient demographic characteristics, comorbidities, functional status, and insurance type did not change over the 6-year period and did not account for these trends.
Vascular Access Maturation
As many as 20% to 60% of newly created AVFs do not mature well enough for use. To improve AVF outcomes, the Hemodialysis Fistula Maturation (HFM) Study Group urged standardized and practical criteria for maturation. They suggested that the HFM study maturation criteria may be unnecessarily complex. Maturation was defined as the use of the fistula with 2 needles for 75% or more of dialysis sessions during a 4-week period with either 4 consecutive dialysis sessions with mean machine blood pump speed of 300 mL/min or greater or a single-pool Kt/V of 1.4 or greater as a measure of solute clearance.
In the Clinical Journal of the American Society of Nephrology4, the HFM group reported that there is no need to extend the maturation ascertainment period beyond 6 months based on their sensitivity and specificity data. They also found that incorporating dialysis machine blood pump speed or solute clearance measures only slightly improves specificity.
Both the original HFM criterion, as well as simpler criteria, provide prognostic information about the long-term outcome of AVFs, according to the study group.
Investigators are actively recruiting patients for a randomized trial (ClinicalTrials.gov NCT04646226) assessing AVF vs AVG placement in patients older than 60 years with suitable vascular anatomy who started hemodialysis with a CVC. Patients must have cardiovascular disease, peripheral arterial disease, and/or diabetes mellitus. The primary outcomes are catheter-free dialysis days and number of infections. The study protocol was published in BMC Nephrology5.
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original references for a full list of authors’ disclosures.
References
- Allon M, Al-Balas A, Young CJ, Cutter GR, Lee T. Effects of a more selective arteriovenous fistula strategy on vascular access outcomes. J Am Soc Nephrol. Published online July 4, 2023. doi:10.1681/ASN.0000000000000174
- Nath KA. Does the primacy of the fistula still prevail in an aging hemodialysis population? J Am Soc Nephrol. Published online July 4, 2023. doi:10.1681/ASN.0000000000000183
- Allon M, Zhang Y, Thamer M, Crews DC, Lee T. Trends in vascular access among patients initiating hemodialysis in the US. JAMA Netw Open. Published online August 1, 2023. doi:10.1001/jamanetworkopen.2023.26458
- Ng JH, Yang W, Dember LM; HFM Study Group. Performance characteristics of candidate criteria for hemodialysis arteriovenous fistula maturation. Clin J Am Soc Nephrol. Published online August 9, 2023. doi:10.2215/CJN.0000000000000248
- Murea M, Gardezi AI, Goldman MP, et al. Study protocol of a randomized controlled trial of fistula vs. graft arteriovenous vascular access in older adults with end-stage kidney disease on hemodialysis: the AV access trial. BMC Nephrol. 2023 Feb 24;24(1):43. doi:10.1186/s12882-023-03086-5
