Is using a mineralocorticoid‑receptor antagonist (MRA) equivalent to adrenalectomy for primary hyperaldosteronism?

MRA vs Adrenalectomy for Primary Aldosteronism: They Are NOT Equivalent

For unilateral primary aldosteronism, adrenalectomy is superior to MRA therapy and should be the preferred treatment when patients are surgical candidates, as it provides better cardiovascular outcomes, mortality reduction, and biochemical control. 1

Treatment Selection Algorithm

The choice between MRA and adrenalectomy depends critically on lateralization status:

For Unilateral PA (Lateralizing Disease):

• Adrenalectomy is the gold standard 2
• Offers potential cure with removal of aldosterone-hypersecreting tissue
• Superior outcomes in:
  • All-cause mortality (OR 0.33,67% reduction) 3
  • Major adverse cardiovascular events (OR 0.55,45% reduction) 3
  • Coronary artery disease (OR 0.33) 3
  • Arrhythmias (OR 0.46) 3
  • Heart failure (OR 0.52) 3
  • End-stage renal disease and mortality 4
  • Biochemical response (81.7% complete response vs 57.1% with MRA) 5

For Bilateral PA (Bilateral Adrenal Hyperplasia):

• MRA therapy is the treatment of choice 2
• Bilateral adrenalectomy requires lifelong glucocorticoid and mineralocorticoid replacement, making it impractical 2

When to Choose MRA Over Surgery (Even in Unilateral PA):

Per the 2025 Endocrine Society guidelines 1, MRA therapy without surgery is appropriate when:

• Patient declines surgery or has no interest in surgical option
• High surgical risk or contraindications to surgery
• Advanced age (>65-70 years, though surgery can still be considered with good quality of life)
• Pregnancy (MRA preferred; surgery only in severe second-trimester cases)
• Non-conclusive or unavailable adrenal venous sampling (AVS)
• Low probability of lateralizing disease based on initial workup
• Multiple comorbidities making them poor surgical candidates

Critical Nuances

Age as a Modifier:

The benefit of adrenalectomy diminishes with advancing age (coefficient 1.084, P=0.036) 3. Older patients may derive less cardiovascular benefit from surgery, making MRA a more reasonable choice in elderly populations.

MRA Efficacy:

While inferior to surgery for unilateral disease, MRA therapy is highly effective 1:

• Consistently superior to other antihypertensive classes when renin is low or ARR is high
• Can achieve adequate blood pressure and biochemical control
• Requires titration to raise renin from baseline 1

The AVS Requirement:

Adrenal venous sampling is essential before surgery to differentiate unilateral from bilateral disease 1. The only exception: patients <35 years with marked PA, hypokalemia, and a >1.0 cm unilateral adenoma on CT where unilateral disease is nearly certain 1.

Common Pitfalls to Avoid

1. Assuming CT imaging alone can guide surgery: CT cannot reliably distinguish unilateral from bilateral disease—AVS is required 1

2. Undertreating with MRA: Many studies show patients receive inadequate MRA doses 6. Titrate to raise renin and control blood pressure, not just to a fixed dose 1

3. Ignoring lateralization status: The treatment choice is fundamentally different for unilateral vs bilateral disease—this must be determined before deciding on therapy

4. Withholding MRA before surgery: Preoperative MRA is safe and associated with better biochemical outcomes post-surgery (81.7% vs 57.1% complete response) without increasing complications 5

Bottom Line on Equivalence

No, they are not equivalent. For unilateral PA, adrenalectomy provides superior long-term cardiovascular protection, mortality reduction, and renal outcomes compared to MRA therapy 3, 7, 4. The 2022 meta-analysis demonstrated this advantage is robust across multiple endpoints and confirmed by trial sequential analysis 3. However, MRA remains highly effective and is the appropriate choice for bilateral disease, high-risk surgical patients, or those who decline surgery 1, 2.