Could Arteriovenous Fistula Creation be Reno-Protective?

This week in BMC Nephrology, an article by Benard et al. associated the creation of arteriovenous fistulas with a reduction in the decline of glomerular filtration rate in pre-dialysis patients. In our first BMC Nephrology blog, Dr. Sumeska Thavarajah explores the potential reno-protective effects of arteriovenous fistulas beyond their primary role as a vascular access.

Advanced vascular access planning and use of an AVF versus a tunneled catheter has previously been associated with better outcomes and less mortality.

A large proportion of time in late chronic kidney disease (CKD) care is devoted to dialysis preparation and, for those pursuing hemodialysis, establishment of a vascular access.  Arteriovenous fistulas (AVFs) are considered the gold standard given their longevity and lower risk of infection.  Guidelines from Kidney Disease Improving Global Outcomes (KDIGO) and international nephrology societies advocate for advanced planning for dialysis vascular access, including the consideration of preserving arm veins, vein mapping prior to surgery, and early referral for vascular surgery. Advanced vascular access planning and use of an AVF versus a tunneled catheter has previously been associated with better outcomes and less mortality.

For nephrology providers, the creation of an AVF access has become a checkbox exercise in the pre-dialysis management of patients with advance CKD, and the consideration of the impact this vascular access has on patient’s kidney function can be lost.

A recent study by Benard et al., published in BMC Nephrology,  looked at the impact of AVF creation on the rate of glomerular filtration rate (GFR) decline in pre-dialysis patients.  Within this retrospective cohort of 146 patients, crude annual estimated GFR (eGFR) decline rates were -3.6ml+/-4ml/min/1.73m2 pre-AVF and -2.28+/- 3.56ml/min/1.73m2 post-AVF creation, suggesting that the AVF creation may have a reno-protective effect.

Comparative findings have previously been reported in the literature. In a retrospective study, 123 CKD patients undergoing AVF creation experienced a drop in the GFR decline rate from 5.9 to 0.5ml/min/year when looking at the 2 years prior and after AVF creation. Similarly, in a cohort of 3026 CKD veterans, the rate of GFR decline decreased from -5.6ml/min/year to -4.1ml/min/year.  This highlights a need for future work into understanding the possible underlying mechanisms contributing to the reduction of GFR decline.

We know that the AVF functions as a low resistance circuit that provides afterload reduction and increased cardiac output. But is it possible that these hemodynamic changes help with blood pressure reduction and increased renal perfusion, slowing the rate of patient’s GFR decline?

The possible benefits of AVF creation on kidney function may promote their use for slowing progression of CKD in addition to the recommended guidelines for managing pre-dialysis patients. Furthermore, if future studies demonstrate AVFs slowing GFR decline, there may be a greater acceptance by patients to move forward earlier with dialysis planning, to preserve their kidney function.

While more prospective studies in this area are needed to determine the mechanisms and impact of AVF on kidney function, these recent findings from Benard et al. highlight a need for Nephrologists to consider the impact of AVF creation beyond their primary role as a hemodialysis vascular access.

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