How long after a fistula (arteriovenous fistula) is created can it be used for dialysis?

Timing for Arteriovenous Fistula Use After Creation

An arteriovenous fistula should not be used for dialysis until at least 1 month after creation, and ideally should be allowed to mature for 6-8 weeks before cannulation. 1

Maturation Timeline for Arteriovenous Fistulae

• A primary arteriovenous fistula requires sufficient time to mature before it can be safely and effectively used for hemodialysis 1
• Premature cannulation (within the first month) may result in a higher incidence of infiltration with associated compression of the vessel by hematoma and permanent loss of the fistula 1
• Cannulation within 14 days of creation is associated with a 2.1-fold increased risk of subsequent fistula failure compared to fistulae cannulated after 14 days 2
• The median maturation time for arteriovenous fistulae is approximately 10.3 weeks 3

Criteria for a Mature Fistula

A mature and usable fistula should meet the following criteria (the "Rule of 6s"):

• Blood flow adequate to support dialysis (typically >600 mL/min) 1
• Diameter greater than 0.6 cm 1
• Depth of approximately 0.6 cm (ideally between 0.5 to 1.0 cm from the skin surface) 1
• Location accessible for cannulation with discernible margins 1

Variations in Practice by Country

• Significant differences exist between countries regarding the timing of initial fistula cannulation 2:
  • Japan and Italy: median time to first cannulation of 25-27 days
  • Germany: median time of 42 days
  • Spain and France: median time of 80-86 days
  • UK and US: median time of 96-98 days 2

Factors Affecting Maturation and Success

• Failure to mature occurs in approximately 23% of arteriovenous fistulae 3
• Risk factors for primary failure include:
  • Female sex (OR 1.59) 3
  • Vascular kidney disease (OR 1.69) 3
  • Distal location (adjusted odds ratio 8.21) 1
  • Diabetes mellitus (adjusted odds ratio 3.19) 1
• Only 26% of created fistulae are reported as mature at 6 months, and 21% of fistulae are abandoned without use 4

Monitoring and Interventions During Maturation

• A new fistula should be monitored regularly during the postoperative 4-6 weeks for:
  • Swelling
  • Hematoma
  • Infiltration
  • Wound healing
  • Signs of failure to mature 1
• If a fistula shows evidence of maturation failure on physical examination or by using duplex ultrasound, it should undergo investigation by 6 weeks after construction 1
• Interventions that may enhance maturation:
  • Hand-arm exercises (squeezing a rubber ball with or without a lightly applied tourniquet) 1
  • Selective obliteration of major venous side branches for slowly maturing fistulae 1

Important Cautions and Pitfalls

• When a new fistula is infiltrated (presence of hematoma with associated induration and edema), it should be rested until swelling is resolved 1
• Repetitive attempts to cannulate an infiltrated fistula carries a high risk of inaccurate cannulation, which may further exacerbate existing swelling and possibly lead to permanent loss of the access 1
• Patients with swelling that does not respond to arm elevation or persists beyond 2 weeks after access placement should receive a venogram or other non-contrast study to evaluate central veins 1
• By 2 weeks post-creation, US measurements can be valuable in predicting 6-week diameter and blood flow, helping to identify fistulas that may not develop optimally 5

Comparison with Other Access Types

• Arteriovenous grafts (AVGs) typically require 3-6 weeks before use 1
• Tunneled cuffed catheters are suitable for immediate use and do not require maturation time 1

In conclusion, while some variation exists in practice, the evidence strongly supports waiting at least 1 month after fistula creation before cannulation, with an ideal maturation period of 6-8 weeks to maximize the chances of successful long-term use and minimize complications.