What are the recommendations for renal artery denervation in patients with resistant hypertension?

Renal Artery Denervation for Resistant Hypertension

Renal artery denervation should be considered only for patients with true resistant hypertension who have failed optimal medical therapy with at least 3 antihypertensive medications including a diuretic. 1

Definition of Resistant Hypertension

Resistant hypertension is defined as:

• Blood pressure that remains above goal (≥140/90 mmHg) despite concurrent use of 3 antihypertensive agents of different classes at optimal doses, with one being a diuretic
• OR blood pressure controlled but requiring 4 or more medications 1

Patient Selection for Renal Artery Denervation

Appropriate Candidates:

• Patients with hemodynamically significant renal artery stenosis and:
  • Accelerated hypertension
  • Resistant hypertension
  • Malignant hypertension
  • Hypertension with unexplained unilateral small kidney
  • Hypertension with medication intolerance 2

Before Considering Renal Denervation:

1. Confirm true resistant hypertension:

   • Verify medication adherence
   • Rule out white coat hypertension (10-20% prevalence in resistant hypertension) using ambulatory or home BP monitoring
   • Ensure proper BP measurement technique 1

2. Optimize medication regimen:

   • Ensure patient is on optimal doses of at least 3 antihypertensive medications including a diuretic
   • Consider adding spironolactone as fourth-line agent (25-50 mg daily) 1

3. Screen for secondary causes of resistant hypertension:

   • Primary aldosteronism (10-20% prevalence)
   • Sleep apnea (high prevalence)
   • Renal artery stenosis
   • Other causes: pheochromocytoma, Cushing's syndrome, thyroid disorders 1

Procedural Considerations

• Renal denervation is performed via percutaneous access from the femoral artery
• It involves radiofrequency ablation of afferent and efferent nerves of the renal sympathetic nervous system 3
• Evaluate renal artery anatomy before procedure, as variant anatomy (e.g., dual renal arteries) increases procedural complexity 1
• Two systems recently received FDA approval: ReCor Medical Paradise system and Symplicity Spyral RDN system 4

Efficacy and Safety

Efficacy:

• Long-term data (36-48 months) shows sustained blood pressure reduction:
  • Mean 24-hour ambulatory systolic BP reduction of 11-15 mmHg 5, 6
  • Office systolic BP reduction of 7-26 mmHg 5, 6
• Improved arterial stiffness: significant reduction in aortic pulse wave velocity 12 months after procedure 5

Safety:

• No evidence of late-emerging complications up to 48 months post-procedure 6
• Composite safety endpoint rate (including all-cause death, end-stage renal disease, embolic events, vascular complications) was approximately 14-15% at 48 months 6

Important Caveats

• Renal denervation is not a first-line BP-lowering intervention for hypertension 1
• Results from clinical trials have been mixed, with some showing significant benefits and others showing no significant difference compared to sham procedures 6, 7
• Medication changes during follow-up may confound assessment of the procedure's effectiveness 7
• Patients should continue antihypertensive medications after the procedure, as renal denervation is an adjunct to, not a replacement for, medical therapy

Clinical Algorithm for Renal Artery Denervation

1. Confirm resistant hypertension:

   • BP ≥140/90 mmHg despite 3+ medications including a diuretic
   • OR controlled BP requiring 4+ medications

2. Rule out pseudo-resistance:

   • Verify medication adherence
   • Perform 24-hour ambulatory BP monitoring
   • Assess for white coat effect

3. Screen for secondary causes of hypertension

4. Optimize medical therapy:

   • Ensure optimal dosing of current medications
   • Add spironolactone if not contraindicated
   • Implement lifestyle modifications (sodium restriction, weight loss, etc.)

5. If BP remains uncontrolled after steps 1-4, consider renal artery denervation

6. Post-procedure:

   • Continue antihypertensive medications
   • Monitor BP at 1 month and every 3-6 months thereafter
   • Adjust medications as needed based on BP response

By following this structured approach, renal artery denervation can be appropriately utilized as an adjunctive therapy for carefully selected patients with true resistant hypertension.