What is the treatment for a patient with 70% renal artery stenosis?

Treatment of 70% Renal Artery Stenosis

Renal artery revascularization through angioplasty and stenting should be considered for patients with 70% renal artery stenosis who have high-risk clinical features and signs of kidney viability. 1

Patient Assessment and Selection

High-Risk Clinical Features

• Treatment-resistant hypertension (elevated BP despite ≥3 antihypertensive medications)
• Progressive decline in renal function
• Recurrent flash pulmonary edema
• Bilateral renal artery stenosis or stenosis in a solitary kidney

Kidney Viability Assessment

• Kidney size >8 cm
• Distinct cortex >0.5 cm
• Albumin-creatinine ratio <20 mg/mmol
• Renal resistance index <0.8

Treatment Algorithm

1. Medical Therapy (First-Line for Most Patients)

• For unilateral 70% stenosis without high-risk features:
  • Optimal medical therapy is recommended 2
  • Antihypertensive medications:
    • Calcium channel blockers
    • Thiazide diuretics at appropriate doses
    • Alpha-blockers
  • Cardiovascular risk reduction:
    • High-intensity statin therapy
    • Low-dose aspirin (may be considered) 2
    • Smoking cessation
    • Diabetes management

CAUTION: ACE inhibitors and ARBs should be used with caution in renal artery stenosis, especially with bilateral stenosis or stenosis in a solitary kidney, due to risk of acute kidney injury 3, 4

2. Revascularization Indications

• Consider renal artery revascularization when:
  • 70% stenosis with high-risk clinical features AND signs of kidney viability 2, 1
  • Bilateral stenosis >70% or stenosis in a solitary kidney 2
  • Recurrent heart failure, unstable angina, or flash pulmonary edema despite maximal medical therapy 2
  • Resistant hypertension 2
  • Hypertension with unexplained unilaterally small kidney or CKD 2

3. Revascularization Procedure

• For atherosclerotic stenosis:

  • Angioplasty with stenting is the preferred approach 1
  • For ostial lesions, stent should extend 1-2 mm into the aorta 1

• For fibromuscular dysplasia:

  • Angioplasty alone (without stenting) is the treatment of choice 2
  • Bailout stenting only if needed 2

Post-Procedure Management

Medication

• Dual antiplatelet therapy for at least 1 month after stent implantation 1
• Continue antihypertensive medications as needed
• Continue statin therapy

Follow-up

• Initial follow-up at 1 month 2
• Subsequent follow-up every 12 months or when new symptoms arise 2
• Monitor:
  • Blood pressure control
  • Renal function (serum creatinine)
  • Duplex ultrasound to assess for restenosis

Re-intervention Considerations

• Consider re-intervention for:
  • In-stent restenosis ≥60% detected by duplex ultrasound 2
  • Recurrent symptoms (diastolic BP >90 mmHg on >3 antihypertensive drugs) 2

  • 20% increase in serum creatinine 2

Important Pitfalls to Avoid

1. Inappropriate use of ACE inhibitors/ARBs: These medications can cause acute kidney injury in patients with bilateral renal artery stenosis or stenosis in a solitary kidney 3, 4

2. Unnecessary revascularization: Routine revascularization for unilateral atherosclerotic RAS without high-risk features is not recommended (Class III, Level A) 2

3. Inadequate follow-up: Failure to monitor for restenosis after revascularization can lead to recurrent symptoms 1

4. Overlooking medical therapy: Even with successful revascularization, comprehensive medical therapy remains essential for cardiovascular risk reduction 5, 6

5. Not confirming hemodynamic significance: Before intervention, confirm hemodynamic significance of stenosis (peak systolic velocity ≥200 cm/s, renal-aortic ratio >3.5) 1

Remember that while revascularization may improve blood pressure control and preserve renal function in appropriately selected patients, medical therapy remains the cornerstone of management for most patients with atherosclerotic renal artery stenosis 5, 7.