What is the preferred vascular access for hemodialysis, an arteriovenous fistula (AVF) or an arteriovenous graft (AVG)?

Arteriovenous Fistula vs Graft for Hemodialysis Access

An arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis over an arteriovenous graft (AVG) due to superior long-term outcomes including lower infection rates, fewer interventions, and better patency once established. 1, 2

Order of Preference for Vascular Access

1. Arteriovenous Fistula (First Choice)

   • Wrist (radial-cephalic) primary AVF
   • Elbow (brachial-cephalic) primary AVF

2. If AVF not possible:

   • Arteriovenous graft of synthetic material (e.g., PTFE)
   • Transposed brachial basilic vein fistula

3. Central Venous Catheters:

   • Should be discouraged as permanent vascular access
   • Use only for specific short-term or long-term indications when AVF/AVG not possible

Advantages of AVF over AVG

• Infection rates: 1-4% for AVFs vs 11-20% for AVGs 2, 3
• Thrombosis rates: 9.0% for AVFs vs 24.7% for AVGs 3
• Lower incidence of vascular steal phenomenon 1
• Better long-term patency once established 1, 2
• Fewer interventions required to maintain patency 1, 2
• Lower maintenance costs over time 2
• Improved mortality outcomes: Patients with grafts have 1.47 times greater mortality risk than those with fistulas 2

Specific AVF Advantages by Type

Wrist (Radial-Cephalic) Fistula Benefits:

• Simple to create
• Preserves more proximal vessels for future access placement
• Low complication rates, especially vascular steal
• Low thrombosis and infection rates once mature 1

Elbow (Brachial-Cephalic) Fistula Benefits:

• Higher blood flow rates than wrist fistulas
• Good option when wrist fistula is not possible 1

Challenges with AVFs

• Longer maturation time (typically 1-4 months before use)
• Potential for failure to mature in some patients
• May be more difficult to cannulate than grafts initially 2

Current Guidelines Approach (2020)

The 2020 KDOQI guidelines take a more nuanced approach than previous guidelines:

• AVF is preferred when "patient circumstances are favorable for a mature, usable AVF" 1
• The choice between AVF and AVG should consider:
  • Vessel characteristics
  • Patient comorbidities
  • Health circumstances
  • Patient preference 1

Clinical Decision Algorithm

1. Evaluate patient for AVF feasibility:

   • Assess vessel adequacy with ultrasound mapping
   • Consider patient's life expectancy and comorbidities
   • Evaluate urgency of dialysis need

2. If good vessels and sufficient time before dialysis needed:

   • Create wrist (radial-cephalic) AVF as first choice
   • Allow 3-4 months for maturation

3. If wrist AVF not feasible:

   • Create elbow (brachial-cephalic) AVF
   • Allow 3-4 months for maturation

4. If AVF not feasible or high risk of non-maturation:

   • Create AVG (particularly in elderly patients with poor vessels)
   • Can be used within 2-4 weeks

5. If immediate dialysis needed:

   • Place tunneled central venous catheter
   • Plan for AVF/AVG creation with catheter removal once access is mature

Common Pitfalls to Avoid

• Delayed referral: Early referral to nephrology/vascular surgery increases successful AVF creation
• Inadequate preoperative assessment: Always perform vascular mapping before access creation
• Premature cannulation: Allowing proper maturation time reduces complications
• Neglecting surveillance: Regular monitoring helps detect dysfunction before thrombosis
• Exhausting proximal sites first: Always start with the most distal viable option

While the 2020 KDOQI guidelines suggest a more individualized approach to access selection, the evidence still supports AVF as the preferred access type when feasible due to superior long-term outcomes, particularly regarding infection rates and interventions needed to maintain patency.