What are the indications for stenting in an adult patient, likely older than 50 years, with a history of hypertension, diabetes, or atherosclerotic disease, and renal artery stenosis?

Indications for Renal Artery Stenting

Medical therapy is the first-line treatment for atherosclerotic renal artery stenosis, and stenting should only be considered in highly specific clinical scenarios where medical management has failed, including recurrent flash pulmonary edema, resistant hypertension despite maximal medical therapy, or progressive renal dysfunction with bilateral disease. 1

Atherosclerotic Renal Artery Stenosis

Medical Therapy First (Class I Recommendation)

Medical management is the primary treatment approach for atherosclerotic renal artery stenosis based on randomized controlled trials showing no benefit of routine stenting over medical therapy alone. 1 The optimal medical regimen must include:

• Three antihypertensive medications at maximally tolerated doses, with one being a diuretic 1, 2
• A renin-angiotensin system (RAS) blocker 1
• High-intensity statin therapy for LDL cholesterol reduction 1
• Antiplatelet therapy 1
• Smoking cessation and hemoglobin A1c control if diabetic 1

Specific Indications for Stenting (Class IIb - May Be Considered)

Stenting may be reasonable only when BOTH clinical AND anatomic criteria are met: 1, 2

Clinical Criteria (Must Have One):

• Recurrent heart failure, unstable angina, or flash pulmonary edema despite maximally tolerated medical therapy 1
• Resistant hypertension (BP ≥130/80 mmHg on 3+ medications including a diuretic) 1
• Hypertension with unexplained unilaterally small kidney or chronic kidney disease 1
• Progressive chronic kidney disease with bilateral renal artery stenosis OR unilateral stenosis in a solitary functioning kidney 1

Anatomic Criteria (Must Have One):

• ≥70% diameter stenosis by visual estimation or intravascular ultrasound 1, 2
• 50-69% diameter stenosis WITH post-stenotic dilatation and/or hemodynamic confirmation (resting systolic gradient ≥20 mmHg, resting mean gradient ≥10 mmHg, or fractional flow reserve <0.8) 1

Critical Caveat for Atherosclerotic Disease

The CORAL and ASTRAL trials demonstrated no benefit of routine stenting over medical therapy for atherosclerotic renal artery stenosis. 1 Therefore, stenting should be performed only in experienced centers due to high restenosis risk and reserved for the specific failure scenarios outlined above. 1

Fibromuscular Dysplasia

Angioplasty WITHOUT Stenting (Class IIa Recommendation)

Percutaneous transluminal renal angioplasty (PTRA) WITHOUT stenting is the treatment of choice for fibromuscular dysplasia. 1, 2 This approach:

• Can restore renal perfusion pressure and normalize blood pressure 1, 2
• Is particularly effective in patients with recent-onset or resistant hypertension 1
• Occurs predominantly in women (mean age 53 years) 1

Stenting is not recommended for fibromuscular dysplasia unless angioplasty alone fails. 1, 2

Post-Procedure Surveillance

After any renal artery intervention, perform renal duplex ultrasound at: 1, 2

• Within 30 days
• At 6 months
• At 12 months
• Annually thereafter

Common Pitfalls to Avoid

• Do not stent atherosclerotic renal artery stenosis without documented failure of optimal medical therapy - the evidence does not support routine revascularization 1
• Do not use stents for fibromuscular dysplasia as first-line treatment - angioplasty alone is superior 1, 2
• Do not consider intervention unless the patient is truly on maximal medical therapy (3 medications at maximal tolerated doses, including a diuretic) 1, 2
• Avoid RAS blockers in bilateral stenosis or stenosis to a solitary kidney without close monitoring - they can cause acute renal failure 1