Arteriovenous Access May Slow Pre-Dialysis Renal Decline

Researchers found that eGFR decline decelerated significantly in patients with AVF/AVG, from -5.6 to -4.1 mL/min/1.73m2 per year.
Researchers found that eGFR decline decelerated significantly in patients with AVF/AVG, from -5.6 to -4.1 mL/min/1.73m2 per year.

For patients with advanced chronic kidney disease (CKD), timely creation of an arteriovenous fistula or graft (AVF/AVG) may be more beneficial than previously thought. A new study links AVF/AVG creation with slowing of renal decline, independent of its maturation status.

Using data from the Transition of Care in CKD (TC-CKD) study, Keiichi Sumida, MD, of the University of Tennessee Health Science Center in Memphis, and colleagues examined 3,026 US veterans (average age 67; 98% male; 75% diabetic) with pre-dialysis placement of AVF/AVG during 2007-2011. The investigators calculated estimated glomerular filtration rates (eGFR) using at least 3 outpatient serum creatinine measurements and the Chronic Kidney Disease Epidemiology Collaboration equation, both before and after dialysis initiation. The eGFR trajectories were then estimated using mixed-effects models adjusted for age, sex, race, diabetes, Charlson comorbidity index, systolic blood pressure, and use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. A group of 3,514 patients without AVG/AVG (and with a tunneled catheter) served as controls.

According to results published online in Nephrology Dialysis Transplantation, 71% had a mature AVF/AVG at dialysis initiation. Median eGFR decline accelerated in the 6 months before dialysis in patients with a tunneled catheter (from -6.0 to -16.3 mL/min/1.73m2 annually). It decelerated significantly, however, in those with AVF/AVG (from -5.6 to -4.1 mL/min/1.73m2 annually). The results were independent of AVF/AVG maturation.

A mature access may benefit circulation in several ways, according to the researchers, such as by reducing arterial stiffness and blood pressure and increasing stroke volume, left ventricular ejection fraction, and cardiac output. These cardiovascular benefits may result from improvements in vascular endothelium from increased nitric oxide and cell proliferation from shear wall stress downstream from the fistula. Similar effects may benefit the kidney. The investigators cited a 2015 study by Thomas A. Golper, MD, and colleagues that proposed slowing of eGFR decline occurs from vasodilatory effects of a functional AVF on previously underperfused renal vascular beds.2

In a novel finding, the current study demonstrated deceleration in eGFR decline in patients with non-mature AVF/AVG. Possible physiologic explanations include ischemic pre-conditioning that provides cardiovascular and renal protection.

“These findings highlight the potential beneficial effects of AVF/AVG creation on kidney function,” Dr Sumida told Renal & Urology News. “And they suggest that timely creation of AVF/AVG prior to dialysis may contribute to delayed onset of dialysis initiation in advanced CKD patients.”

As most patients were male veterans, the findings may not be generalizable to women. The researchers also could not rule out the possible influence of confounders such as proteinuria, muscle mass, changes in volume status, and quality of care. 

Sources

1.   1. Sumida K, Molnar MZ, Potukuchi PK, et al. Association between vascular access creation and deceleration of estimated glomerular filtration rate decline in late-stage chronic kidney disease patients transitioning to end-stage renal disease. Nephrol Dial Transplant. doi: 10.1093/ndt/gfw220.

2. Golper TA, Hartle PM, and Bian A. Arteriovenous fistula creation may slow estimated glomerular filtration rate trajectory. Nephrol Dial Transplant. doi: 10.1093/ndt/gfv082.

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