What is the best course of treatment for a patient with an iatrogenic (caused by medical intervention) arteriovenous (AV) fistula in the femoral region, likely with a history of cardiovascular disease and invasive procedures?

Management of Iatrogenic Arteriovenous Fistula in the Femoral Region

For iatrogenic femoral arteriovenous fistulas, initial management should be conservative observation with duplex ultrasound surveillance for asymptomatic lesions smaller than 2.0 cm in diameter, as approximately 38-61% close spontaneously within 1-12 months, while larger fistulas (≥2.0 cm) or those causing symptoms require intervention with ultrasound-guided thrombin injection as first-line therapy, reserving surgical repair for failures, complications, or limb-threatening presentations. 1, 2

Initial Diagnostic Approach

• Obtain duplex ultrasound immediately when iatrogenic femoral AVF is suspected, as physical examination alone misses over 60% of catheter-related femoral AVFs 1
• Document the exact size of the fistula, flow characteristics, and presence of any associated pseudoaneurysm 1
• Assess for hemodynamic significance by evaluating cardiac output effects and distal limb perfusion 3, 4

Size-Based Treatment Algorithm

Small AVFs (<2.0 cm diameter)

• Conservative management is appropriate for asymptomatic fistulas smaller than 2.0 cm, as 61% resolve spontaneously within 7-52 days and only 11% ultimately require surgical intervention 1
• Perform follow-up duplex ultrasound at 1 month to document closure or persistence 1
• Continue observation up to 12 months, during which 38% of all AVFs close spontaneously 2
• Avoid anticoagulation intensification during observation period, as this may extend AVF persistence 2

Large AVFs (≥2.0 cm diameter)

• Ultrasound-guided thrombin injection (100-3000 international units) is the preferred first-line intervention, achieving 93% success rates with only 4.1% requiring subsequent surgery 1
• Alternative option is ultrasound-guided compression therapy, though this causes more pain, requires longer compression times, and has lower success rates particularly for large fistulas 1
• Percutaneous coil embolization represents another endovascular option with durable results at 10-month follow-up 5

Indications for Urgent Surgical Repair

Immediate surgical intervention is mandatory for:

• Rupture into retroperitoneal space or upper thigh 1
• Venous thrombosis from compression of adjacent femoral vein 1
• Painful neuropathy from femoral nerve compression 1
• High-output cardiac failure (rare but life-threatening presentation) 3, 6
• Acute limb ischemia from associated arterial thrombosis or distal embolization 4, 6
• Failure of thrombin injection or compression therapy 1
• Persistent or recurrent AVF ≥2.0 cm after non-operative management 1

Surgical Technique When Required

• Open surgical repair remains the gold standard for complex cases, involving direct exposure, fistula takedown, and primary arterial/venous repair 3, 4, 6
• Ensure complete evaluation of both arterial and venous systems intraoperatively, as associated thrombosis may be present 4
• Consider endovascular approaches (embolization, closure devices) only in anatomically favorable, limited cases 6

Critical Monitoring Parameters

• Cardiac assessment for volume overload signs (though highly unlikely even with persistent AVF) 2
• Distal limb perfusion monitoring for ischemic changes 4, 6
• Serial duplex ultrasound at 1,3,6, and 12 months for conservatively managed cases 1, 2

Common Pitfalls to Avoid

• Never dismiss persistent leg swelling or new cardiac symptoms in patients with known femoral AVF, as these may indicate hemodynamic decompensation requiring urgent intervention 3, 6
• Do not perform repeat femoral catheterization on the ipsilateral side while AVF is present, as this risks catastrophic complications 4
• Avoid premature surgical intervention for small asymptomatic AVFs, as the natural history favors spontaneous closure and surgery carries unnecessary risk 1, 2
• Do not continue anticoagulation at therapeutic doses during observation period unless absolutely required for other indications, as this impairs spontaneous closure 2

Special Considerations for High-Risk Patients

• Patients on chronic anticoagulation (warfarin) have 2.34-fold increased risk of AVF formation and may have delayed spontaneous closure 2
• Female patients and those with arterial hypertension have higher baseline risk (OR 1.84 and 1.86 respectively) 2
• Left groin punctures carry 2.21-fold increased risk compared to right-sided access 2