Treatment of Occluded Arteriovenous Dialysis Graft
Thrombosed AV grafts should be treated with either surgical thrombectomy or percutaneous pharmacomechanical/mechanical thrombolysis, followed by correction of the underlying stenosis with angioplasty or surgical revision. 1
Pathophysiology and Approach to Treatment
Occlusion of arteriovenous (AV) grafts is primarily caused by venous stenosis, with over 90% of thrombosed grafts showing venous stenosis on angiography. This stenosis increases resistance to blood flow, leading to increased venous pressure, decreased blood flow, and ultimately thrombosis 1.
The treatment approach should follow these essential steps:
- Rapid intervention - Treatment should be performed quickly after detection to minimize the need for temporary access 1
- Thrombus removal - Either surgical thrombectomy or percutaneous mechanical/pharmacomechanical thrombolysis 1
- Diagnostic fistulogram - To identify underlying stenosis 1
- Stenosis correction - With angioplasty or surgical revision 1
- Post-procedure monitoring - To ensure return to normal function 1
Treatment Options
1. Endovascular Approach (First-Line)
- Mechanical thrombectomy options:
- Suction thrombectomy
- Balloon thrombectomy
- Clot maceration
- Pharmacologic thrombolysis (e.g., alteplase)
- Balloon angioplasty for underlying stenosis
- Stent placement for elastic stenoses or recurrent stenosis within 3 months 1
2. Surgical Approach
- Surgical thrombectomy with revision
- Graft replacement if needed
The Society of Interventional Radiology guidelines recommend endovascular management as the preferred first-line therapy for dialysis access thrombosis 1.
Expected Outcomes
Patency goals following thrombosis treatment should be:
| Technique | Expected Patency |
|---|---|
| Percutaneous thrombolysis with PTA | 40% unassisted patency at 3 months |
| Surgical thrombectomy and revision | 50% unassisted patency at 6 months, 40% at 1 year |
| Immediate patency (both techniques) | 85% |
Special Considerations
Venous Outflow Stenosis
- Present in 85% of thrombosis cases 1
- When treatment fails to address underlying venous stenosis, there is >90% chance of rapid re-thrombosis 1
- Central vein stenosis should be treated with percutaneous transluminal angioplasty 1
Recurrent Thrombosis
- Consider surgical revision if thrombosis occurs >2 times within a month 1
- PTA failure is defined as needing more than two PTA interventions within 3 months 1
- Consider hypercoagulability testing in patients with frequent thrombotic occlusions 1
Infection
- Infected AV grafts require surgical treatment
- Surgical exploration and removal of infected graft material is necessary as it acts as a foreign body 1
Pitfalls and Caveats
Delayed treatment - Early diagnosis and intervention within 24-48 hours is crucial for optimal outcomes 1
Failure to identify underlying stenosis - Always perform fistulogram to identify and treat the underlying cause 1
Inadequate treatment of venous stenosis - This is the most common cause of recurrent thrombosis 1
Aneurysm/pseudoaneurysm complications - These can contribute to thrombosis and complicate successful endovascular thrombectomy 1
Stent placement limitations - Stents should be reserved for surgically inaccessible stenoses that fail PTA or for elastic stenoses 1
The evidence clearly shows that stenosis detected and treated before thrombosis has better outcomes than stenosis treated after thrombosis occurs. Preventive monitoring and early intervention for stenosis can significantly improve long-term graft patency 1, 2.