What is the treatment approach for a renal artery aneurysm?

Treatment Approach for Renal Artery Aneurysm

Renal artery aneurysms (RAAs) require surgical or endovascular treatment when they are noncalcified and larger than 2 cm in diameter, particularly in premenopausal women due to increased rupture risk during pregnancy, or when they contribute to renin-mediated hypertension. 1

Indications for Intervention

Size-Based Criteria

• RAAs >2 cm in diameter warrant intervention, especially if noncalcified, due to rupture risk 1
• Rapid growth (≥5 mm in 6 months or ≥10 mm per year) is an indication for treatment 2
• Smaller, well-calcified saccular aneurysms can be observed with surveillance imaging 3

Clinical Indications

• Premenopausal women with RAAs >2 cm require treatment due to substantially elevated rupture risk during pregnancy 1
• Renovascular hypertension that is refractory or requires multiple medications may benefit from aneurysm repair 1, 4
• Symptomatic aneurysms (flank pain, hematuria, or signs of rupture) require immediate intervention 3

Treatment Modalities

Open Surgical Repair

Open surgical repair via aneurysmectomy with arterial reconstruction (AAR) remains the primary treatment for complex RAAs and those associated with hypertension. 4

• In situ repair techniques include tangential aneurysmectomy with primary arteriorrhaphy, saphenous vein patch angioplasty, or bypass grafting 5
• Ex vivo reconstruction is reserved for complex anatomy requiring extensive arterial reconstruction 4
• Open repair demonstrates superior outcomes for hypertension control, with significant reduction in antihypertensive medication requirements (2.7 medications pre-operatively vs 1.6 post-operatively, p=0.03) 4
• Nephrectomy should be avoided unless the kidney is severely infarcted or the aneurysm has ruptured 5, 3

Endovascular Approaches

Endovascular treatment with coil embolization or covered stent placement is an effective alternative, particularly for patients at high surgical risk 1, 6

• Technical success rates range from 67% to 100% with minimal complications 1
• Endovascular options include angioembolization or covered stent placement 6
• Critical limitation: inability to directly assess renal parenchymal perfusion after treatment, unlike open repair 1

Post-Intervention Monitoring

Close surveillance for flank pain is mandatory after catheter-based intervention to detect potential renal ischemia, as direct visualization of the kidney is not possible with endovascular approaches 1

• Monitor for flank pain as a sign of renal ischemia or infarction 1
• Serial imaging to confirm aneurysm exclusion and assess renal perfusion 6, 7
• Blood pressure monitoring and adjustment of antihypertensive medications 4

Surveillance for Non-Operative Cases

Small (<2 cm), well-calcified aneurysms can be followed with serial CT or ultrasound imaging 1, 3

• Surveillance intervals should be based on aneurysm size and growth rate 2, 7
• No ruptures occurred in one series of patients with aneurysms 1.0-2.4 cm followed for 2-147 months 1

Additional Considerations

Evaluate for concomitant aneurysms in other vascular beds, as RAAs frequently coexist with abdominal aortic aneurysms and other peripheral aneurysms 2, 8

Common Pitfalls

• Avoid nephrectomy when kidney-preserving repair is feasible, as in situ reconstruction provides excellent long-term outcomes 5
• Do not defer treatment in premenopausal women with aneurysms >2 cm, as pregnancy dramatically increases rupture risk with maternal mortality up to 70% 1
• Ensure close post-procedural monitoring after endovascular repair, as the inability to directly visualize the kidney increases risk of undetected ischemia 1