Why “fistula first” matters: Increased durability, less interventions, and decreased costs

Abstract

Over the past 15 year, the National Kidney Foundation has recognized the overall poorer results with prosthetic arteriovenous graft (AVG) placement over an arteriovenous fistula (AVF) creation. To this end, it made clear recommendations that AVF creation should approach 65% of all hemodialysis access thru the now well-known Kidney Disease Outcomes and Quality Initiative (KDOQI) guidelines. AVF creation over AVG placement has now become the ‘‘gold-standard’’ and is primarily done by most surgeons when technically feasible. Unfortunately, AVF malfunction occurs from three major sources: stenoses of the juxta-anastomotic region, intra-AVF stenosis likely due to vein mobilization during the AVF creation, or outflow venous stenosis formation due to intimal hyperplasia and hemodynamic strain. Hence, when AVFs malfunction, intervention thru percutaneous transluminal angioplasty (PTA) is usually required. Conversely, AVGs tend to thrombose more readily than AVFs but because it is a synthetic conduit, the majority of the stenoses are anastomotic (venous primarily and, rarely, arterial). Therefore, when an AVG malfunctions, it is usually due to a thrombotic event, necessitating a percutaneous thrombectomy with an adjunctive PTA and/or stenting procedure to treat the underlying lesion. The AVF vs. AVG issue is further complicated by the fact that various studies have found that AVF creation is associated with a prolonged maturation time and, therefore, an increased initial central venous catheter use. Given these two types of accesses, what are the economic costs associated with keeping them functional and does an aggressive angiography program help prevent access thrombosis? Bittl et al tackle these questions in this issue of CCI through a 7-year economic analysis of over 800 patients with stage V chronic kidney disease, 560 of who required at least one intervention. They found that the median number of access angiograms per patient was 3, underscoring the commitment required for such a patient population to keep an access functional. Their results are in line with the growing literature that in per patient years, AVGs require almost twice as many interventions than AVFs to maintain patency. Moreover, they found a fourfold greater rate of thrombotic events in AVGs over AVF; as the rate of AVF creation increased, there was a decrease in the thrombotic rate. They next attempted to determine if a lower thrombosis rate was due to a preemptive angiography program of AV accesses. Logistic regression did suggest that both of these contributed to the lowering of the thrombotic rates independently; however, because of the increased rate of AVF creation during the study period, it is difficult to separate these two possibly confounding variables. So, is it cost-saving to do preemptive angiography on arteriovenous accesses? The answer is yes, if the rate of AVF creation is also high (over 65% as KDOQI guidelines suggest). A predominance of AVF creation is likely the largest contributor of cost-reduction. In the future, studies to determine which AVF stenoses should be treated to keep them functional will help guide how aggressive a preemptive angiography program to implement. In the mean time, we can conclude that KDOQI guidelines also seem to make economic sense.