How to manage a thrombosed arteriovenous fistula (AVF) that is not in use?

Management of Thrombosed Arteriovenous Fistula Not in Use

A thrombosed arteriovenous fistula (AVF) that is not currently in use should still be declotted as soon as possible to preserve future access options and avoid the need for catheter placement. 1

Rationale for Declotting Non-Used AVFs

Early intervention for thrombosed AVFs is critical for several important reasons:

• Preservation of vascular access sites: Each patient has limited sites for potential dialysis access, making preservation of existing AVFs crucial for long-term survival
• Prevention of catheter dependence: Catheter use is associated with higher infection rates and mortality
• Better long-term patency: Prompt declotting leads to better outcomes compared to delayed intervention
• Future access needs: Even if not currently in use, the AVF may be needed in the future

Declotting Approach

The recommended approach follows a time-sensitive algorithm:

1. Timing: Intervention should occur within 24-48 hours of thrombosis detection 1
2. First-line treatment: Endovascular management is preferred over surgical techniques 1
3. Procedural options:
   • Mechanical thrombectomy (suction, balloon thrombectomy, clot maceration)
   • Pharmacologic thrombolysis
   • Balloon angioplasty for underlying stenosis
   • Combination of these techniques

Success Rates and Outcomes

Endovascular declotting of thrombosed AVFs shows promising results:

• Initial success rate: 75-94% for thrombolysis/thrombectomy 1
• Patency rates:
  • 3-month patency: 37-58%
  • 6-month primary patency: 18-39%
  • 6-month secondary patency: 62-80%
  • 12-month secondary patency: 57-69% 1

Native AVFs have better long-term outcomes after declotting compared to grafts, with better primary patency rates after the first month of follow-up 1, 2.

Anatomical Considerations

The approach may vary based on the location of thrombosis:

• Forearm AVFs with juxta-anastomotic stenosis: Surgical thrombectomy with placement of a new anastomosis may be preferred 1
• Proximal/central thromboses: Interventional endoluminal techniques are recommended 1

Special Considerations

• Thrombus burden: The amount of thrombus can vary significantly in thrombosed AVFs 3

  • Minimal thrombus: Balloon angioplasty to correct underlying stenosis may be sufficient
  • Moderate-to-severe thrombus: Requires thromboaspiration for successful declotting

• Recurrent thrombosis: If thrombosis occurs more than twice within a month, consider:

  • Vascular surgery consultation for access revision
  • Hypercoagulability testing for thrombophilia 1

• Aneurysmal AVFs: These may be more challenging to declot due to chronic intraluminal thrombus in aneurysmal regions 1

Pitfalls to Avoid

• Delay in treatment: Waiting too long leads to progressive thrombus growth, making procedures more difficult and reducing success rates 1
• Overlooking underlying stenosis: About 90% of access thromboses are secondary to anatomic stenosis that must be addressed 1
• Ignoring alternative causes: Consider hypotension, hypercoagulable states, decreased cardiac output, and access site infection as potential contributors to thrombosis 1

Even for AVFs not currently in use, prompt declotting is essential to maintain vascular access options and improve long-term patient outcomes.