What is the recommended treatment for a patient with an arteriovenous (AV) fistula aneurysm?

Treatment of AV Fistula Aneurysm

Open surgical repair is the definitive treatment for symptomatic, large, or rapidly expanding AV fistula aneurysms, while asymptomatic aneurysms require only monitoring and avoidance of cannulation through the aneurysm site. 1

Initial Assessment and Risk Stratification

Asymptomatic aneurysms do not require definitive treatment. 1 The presence of an aneurysm alone, without symptoms or complications, is managed conservatively with:

• Regular monitoring at each dialysis session by trained staff to detect changes in size, skin integrity, or symptoms 1
• Duplex ultrasound to assess aneurysm size, presence of stenosis or thrombus, flow rate (Qa), and arterial inflow/venous outflow status 1
• Patient education on emergency procedures for potential rupture 1

Symptomatic or high-risk aneurysms require surgical evaluation. 1 Indications for proactive surgical assessment include:

• Skin breakdown or thinning overlying the aneurysm 1
• Rapid expansion of the aneurysm 1
• Large size (though specific thresholds are not defined in guidelines) 1
• Pain or other symptoms 1

Emergency Indications

Obtain emergent surgical assessment and treatment for aneurysm erosion or hemorrhage. 1 These complications represent life-threatening emergencies requiring immediate intervention to prevent exsanguination. 1

Pre-Treatment Imaging

Before definitive treatment, obtain imaging of the entire access circuit including arterial inflow and venous outflow to identify stenotic lesions that may need correction during the aneurysm repair. 1 Underlying stenosis is often the precipitating factor for aneurysm development and must be addressed to prevent recurrence. 1

Definitive Treatment Algorithm

First-Line: Open Surgical Repair

Open surgical treatment is the definitive therapy for AV access aneurysms/pseudoaneurysms. 1 The specific surgical approach depends on:

• Anastomotic aneurysms/pseudoaneurysms: These almost always require definitive surgical treatment, typically involving revision of the anastomosis 1
• Non-anastomotic aneurysms: Surgical options include aneurysmorrhaphy (excision with primary repair) or aneurysm excision with interposition grafting 2
• Multiple aneurysms: Consider staged repair to avoid the need for bridging central venous catheters in the perioperative period 1

Staged repair is superior to simultaneous repair when two aneurysms require treatment. 3 A 2024 study demonstrated that unstaged (simultaneous) repair of two concurrent aneurysms resulted in higher early thrombosis rates (4.3% vs 1.3-2.1%), increased need for short-term tunneled catheters (8.9% vs 3.4-4.4%), and decreased 5-year functional dialysis compared to staged repair. 3 In staged repair, treat the most symptomatic aneurysm first, allow the incision to heal, then address the second aneurysm. 3

Alternative: Covered Stent-Grafts (Limited Role)

Use covered intraluminal stents (stent-grafts) only in special circumstances such as:

• Specific patient contraindication to surgery 1
• Lack of surgical option 1

This approach carries significant limitations:

• Associated risk of infection 1
• Not FDA-approved for this indication 1
• If used, avoid cannulating over the stent graft segment whenever possible 1

Endovascular approaches may be considered in elderly or debilitated patients at high surgical risk, though this represents off-label use. 4

Cannulation Management During Treatment Planning

Avoid cannulating through the aneurysm segment if alternative sites exist. 1 If absolutely no suitable alternative sites are available, cannulate the sides (base) of the aneurysm rather than the top to minimize risk of rupture. 1

Critical Pitfalls to Avoid

• Do not delay treatment of symptomatic or high-risk aneurysms, as this leads to thrombosis, access failure, or catastrophic rupture 1
• Do not place stents in cannulation segments, as this compromises future access use 1
• Do not perform simultaneous repair of two aneurysms when staged repair is feasible, as this increases complications 3
• Do not treat asymptomatic aneurysms definitively, as the intervention risk outweighs benefit 1
• Do not ignore underlying stenosis in the arterial inflow or venous outflow, as failure to correct these lesions leads to aneurysm recurrence 1

Prevention

Implement proper cannulation techniques to reduce aneurysm occurrence, including rotation of needle sites and avoidance of repeated puncture in the same location. 1