When can an arteriovenous (AV) graft be used for dialysis and when is an ultrasound typically performed after AV graft creation?

When to Use an AV Graft After Creation

An AV graft should not be cannulated until at least 14 days after placement, with 3 weeks being the ideal timeframe to allow for proper tunnel adhesion and reduction of surgical swelling. 1

Timing of First Cannulation

Minimum Waiting Period

• Avoid cannulation within the first 14 days because the graft has not yet adhered to the subcutaneous tunnel, and premature use risks hematoma formation, bleeding into the graft tunnel, and potential access site loss 1
• The graft may be considered mature when swelling has reduced sufficiently that the graft's course is easily palpable, but never before 14 days post-placement 1

Optimal Timing

• The ideal maturation period is 3-6 weeks after graft placement to ensure proper healing and tissue integration 2
• Some practitioners advocate for immediate cannulation if the tunnel is carefully constructed, but this approach cannot be recommended until randomized trials demonstrate similar long-term patency with immediate versus delayed cannulation 1

Clinical Assessment Before First Use

• The access site must meet these criteria before cannulation 1, 2:
  • Swelling has substantially subsided
  • The graft course is easily palpable along its entire length
  • No signs of hematoma or fluid collection
  • Adequate thrill present throughout the graft

Warning: Edematous Arm Contraindication

• Never attempt to cannulate a graft in an edematous arm, as this leads to inaccurate needle insertion, hematoma formation, and graft wall laceration 1
• Expected post-operative edema should resolve with arm elevation within the first 2 weeks 1

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When to Obtain Ultrasound After AV Graft Creation

Routine Surveillance Schedule

Early Post-Operative Period (2-6 Weeks)

• Obtain ultrasound at 4-6 weeks post-creation as a mandatory baseline assessment to evaluate graft maturation and identify early dysfunction 3
• This early evaluation predicts ultimate maturation success and detects correctable problems before first cannulation 3

Indication-Based Imaging (Within First 2 Weeks)

• Perform venography or non-contrast studies if edema and swelling persist beyond 2 weeks after graft insertion, as this suggests occult central venous stenosis or occlusion 1
• Persistent swelling that does not resolve with arm elevation requires immediate vascular imaging 1

Ongoing Surveillance After Maturation

• Monthly access flow measurements using ultrasound dilution, conductance dilution, thermal dilution, or Doppler techniques are recommended once the graft is in use 1
• Prospective surveillance for hemodynamically significant stenosis, when combined with correction, improves patency and decreases thrombosis incidence 1

Physical Examination Protocol

• Weekly physical examination should be performed and includes inspection and palpation for pulse and thrill at the arterial, mid, and venous sections of the graft 1
• Physical examination by trained staff is highly accurate for assessing graft function and detecting dysfunction 3

When Ultrasound is Diagnostic (Not Surveillance)

• Obtain duplex ultrasound when physical examination detects 3:
  • Absent or diminished thrill
  • Pulsatile flow suggesting downstream stenosis
  • Arm swelling or signs of venous hypertension
  • Difficulty with cannulation or elevated venous pressures during dialysis
  • Unexplained reduction in dialysis adequacy

Common Pitfalls to Avoid

• Do not wait for graft thrombosis before obtaining imaging—surveillance detects stenosis before complete occlusion occurs 1
• Do not dismiss erythema along the graft path as infection if it follows the surgical tunnel; this typically represents surgical inflammation rather than infection and should not prevent graft use 1
• Do not rely solely on physical examination for ongoing surveillance; monthly flow measurements provide objective data that predicts impending failure 1