Vascular Access for Hemodialysis Patients: New Data Should Guide Decision Making

Abstract

This commentary critically examines key assumptions and recommendations in the 2006 Kidney Disease Outcomes Quality Initiative vascular access guidelines, and argues that several are not relevant to the contemporary United States hemodialysis population. First, the guidelines prefer arteriovenous fistulas (AVFs) over arteriovenous grafts (AVGs), on the basis of their superior secondary survival and lower frequency of interventions and infections. However, intent-to-treat analyses that incorporate the higher primary failure of AVFs, demonstrate equivalent secondary survival of both access types. Moreover, the lower rate of AVF versus AVG infections is counterbalanced by the higher rate of catheter-related bloodstream infections before AVF maturation. In addition, AVFs with assisted maturation (interventions before successful AVF use), which account for about 50% of new AVFs, are associated with inferior secondary patency compared with AVGs without intervention before successful use. Second, the guidelines posit lower access management costs for AVFs than AVGs. However, in patients who undergo AVF or AVG placement after starting dialysis with a central venous catheter (CVC), the overall cost of access management is actually higher in patients receiving an AVF. Third, the guidelines prefer forearm over upper arm AVFs. However, published data demonstrate superior maturation of upper arm versus forearm AVFs, likely explaining the progressive increase in upper arm AVFs in the United States. Fourth, AVFs are thought to fail primarily because of aggressive juxta-anastomotic stenosis. However, recent evidence suggests that many AVFs mature despite neointimal hyperplasia, and that suboptimal arterial vasodilation may be an equally important contributor to AVF nonmaturation. Finally, CVC use is believed to result in excess mortality in patients on hemodialysis. However, recent data suggest that CVC use is simply a surrogate marker of sicker patients who are more likely to die, rather than being a mediator of mortality.

Keywords: Arteriovenous Shunt, Surgical; Bacteremia; Biomarkers; Catheter-Related Infections; Central Venous Catheters; Constriction, Pathologic; Decision Making; Forearm; Hyperplasia; Kidney Diseases; Vasodilation; arteriovenous fistula; arteriovenous graft; dialysis; dialysis catheter.

Figure 1.

Secondary survival of AVFs is superior to that of AVGs when primary failures are excluded, but similar when they are included. Reprinted from reference , with permission.

Figure 2.

Secondary access survival after successful use is inferior if an intervention was required prior to successful use. Access patency was shorter for AVFs with prior intervention than for AVFs without interventions (P<0.001). Access patency was shorter for AVGs with prior interventions than AVGs without intervention (P<0.001). Access patency was similar for AVFs and AVGs without prior interventions (P=0.16). Access patency was worse for AVFs with prior interventions than for AVGs without prior interventions (P=0.01). Modified from reference .

Figure 3.

The median annual cost of vascular access management is greater for AVF versus AVG in patients initiating hemodialysis with a CVC and subsequently undergoing access placement. The comparisons are shown for several patient subsets, divided by sex, age, diabetes mellitus (DM) status, and congestive heart failure (CHF) status. * P<0.05; ** P<0.01. Reprinted from reference , with permission.

Figure 4.

AVF maturation reflects the balance between inward remodeling (intimal hyperplasia) and outward remodeling (vasodilation). Intimal hyperplasia without concurrent outward remodeling results in AVF nonmaturation. In contrast, concurrent inward and outward remodeling results in a mature AVF. Modified from reference .

Figure 5.

Patient survival after initiation of hemodialysis with a CVC is higher in those with versus without attempted pre-ESKD AVF creation. Group 1, patients who initiated dialysis with an AVF; group 2, patients who initiated dialysis with a CVC after undergoing pre-ESKD AVF surgery (even if the AVF failed to mature); group 3, patients who initiated dialysis with a CVC without pre-ESKD AVF creation. Patient survival in group 2 was much more similar to that of group 1 than group 3. Reprinted from reference , with permission.