What is the preferred choice between a dialysis fistula and a graft (arteriovenous graft) for dialysis access?

Arteriovenous Fistula vs Graft for Dialysis Access

Arteriovenous fistulas (AVFs) are strongly preferred over arteriovenous grafts (AVGs) for hemodialysis access due to their superior long-term patency, lower rates of infection, and reduced mortality and morbidity. 1

Advantages of Arteriovenous Fistulas

• Lower complication rates:

  • Infection rates of only 1-4% for AVFs compared to 11-20% for AVGs 1
  • Significantly lower thrombosis rates (3-7 times fewer access events than grafts) 1
  • Reduced incidence of vascular steal phenomenon 1

• Superior longevity:

  • Better 4-5 year patency rates compared to other access types 1
  • Require fewer interventions to maintain patency 1
  • Lower maintenance costs over time 1

• Improved patient outcomes:

  • Associated with increased survival and lower hospitalization rates 1
  • Patients with grafts have 1.47 times greater mortality risk than those with fistulas 1
  • Patients with catheters have 2.3 times greater mortality risk than those with fistulas 1

Limitations of Arteriovenous Fistulas

• Longer maturation time (1-4 months) before use 1
• Potential failure to mature in some patients 1
• May be more difficult to cannulate than grafts in some cases 1
• Requires adequate vessel anatomy for successful creation 1

When to Consider Arteriovenous Grafts

While AVFs are preferred, AVGs may be appropriate in specific circumstances:

• Patients with inadequate vasculature for fistula creation 2
• When urgent dialysis access is needed (though tunneled catheters are often used as a bridge) 1
• Patients with limited life expectancy (<6-12 months) 1
• After exhaustion of suitable sites for AVF creation 1

Access Planning Algorithm

1. Start distally and move proximally to preserve future access sites 1

   • Wrist (radiocephalic) fistula is first choice
   • Elbow (brachiocephalic) fistula is second choice
   • Upper arm (brachiobasilic) fistula is third choice
   • Consider AVG only after these options are exhausted or deemed unsuitable

2. Pre-access evaluation:

   • Vascular mapping with ultrasound to assess vessel adequacy
   • Consider angiography or MRA for complex cases 1
   • Document reasons if choosing to bypass more distal sites 1

3. Monitoring after creation:

   • Regular surveillance to detect dysfunction before thrombosis 1
   • Target thrombosis rates: <0.25 episodes/patient-year for AVFs and <0.5 episodes/patient-year for AVGs 1

Important Considerations

• Age alone should not preclude AVF creation - even patients over 80 can benefit from AVFs 3
• Early referral to nephrology increases the probability of successful AVF creation 1
• The 2019 KDOQI guidelines shifted from a "Fistula First" approach to a more individualized "Patient Life-Plan" approach that considers each patient's specific access needs 1

Pitfalls to Avoid

• Premature exhaustion of anatomic sites by initially bypassing more distal options 1
• Delayed referral for access planning, leading to catheter dependence 1
• Inadequate monitoring of access function, resulting in thrombosis 1
• Failure to address early signs of access dysfunction 1

The evidence clearly demonstrates that AVFs provide superior outcomes in terms of morbidity, mortality, and quality of life compared to AVGs, making them the preferred choice for most patients requiring hemodialysis access.