Should we add a Mineralocorticoid Receptor Antagonist (MRA) to the treatment regimen of a patient with a Left Ventricular Ejection Fraction (LVEF) of 37%?

Adding Mineralocorticoid Receptor Antagonist (MRA) for LVEF 37%

Yes, a Mineralocorticoid Receptor Antagonist (MRA) should be added to the treatment regimen for a patient with LVEF of 37%, as this falls within the guideline recommendation for MRAs in patients with LVEF ≤35-40% who have heart failure symptoms. 1

Guideline Recommendations for MRA Use

• MRAs are recommended in patients with NYHA class II-IV heart failure who have LVEF of 35% or less to reduce morbidity and mortality (Class I, Level of Evidence: A) 1
• MRAs are also recommended following acute MI in patients with LVEF of 40% or less who develop symptoms of heart failure or have diabetes mellitus (Class I, Level of Evidence: B) 1
• Despite strong evidence, MRAs remain underutilized, with only about 33% of eligible patients receiving this therapy 1

Patient Selection Criteria

Before initiating MRA therapy, ensure the patient meets these criteria:

• LVEF ≤35% (patient's LVEF of 37% is very close to this threshold) 1
• NYHA class II-IV symptoms 1
• Already on beta-blockers and ACE inhibitors/ARBs/ARNI 1
• Serum creatinine ≤2.5 mg/dL for men and ≤2.0 mg/dL for women (or eGFR >30 mL/min/1.73 m²) 1
• Serum potassium <5.0 mEq/L 1

Clinical Benefits of MRA Therapy

• Reduces mortality by 30% in patients with heart failure and reduced ejection fraction 2
• Reduces risk of hospitalization for cardiac causes by 30% 2
• Benefits appear consistent across subgroups, with potentially greater benefit in patients with low baseline serum potassium 2

Monitoring Requirements

• Check potassium levels and renal function 3 days and 1 week after initiating therapy 1
• Continue monitoring at least monthly for the first 3 months 1
• Monitor for hyperkalemia, which occurs in 2-5% of clinical trial patients but up to 24-36% in real-world settings 1
• If potassium exceeds 5.5 mEq/L, consider dose reduction or discontinuation 1

Dosing Considerations

• Start with low dose (spironolactone 25 mg once daily or eplerenone 25 mg once daily) 2, 3
• May reduce to 25 mg every other day if not tolerated 2
• May increase to 50 mg daily if tolerated at lower dose after 4-8 weeks 2, 3
• Mean effective dose in clinical trials was approximately 26 mg daily 2

Implementation Challenges

• Despite Class I recommendations, MRAs remain significantly underutilized, with only 22-33% of eligible patients receiving this therapy 1, 4
• Only about 9.5% of eligible patients not prescribed an MRA at discharge receive it within 3 months of follow-up 4
• Factors associated with higher likelihood of MRA prescription include lower LVEF and more recent care (increasing trend over time) 4

Special Considerations

• For patients with LVEF between 35-40%, clinical judgment is warranted, but given the mortality benefit and the patient's LVEF being very close to the 35% threshold, adding an MRA is reasonable 1, 5
• In patients with myocardial infarction and heart failure, MRA use was associated with better long-term survival in patients with LVEF <40% 5
• The benefits of MRA therapy appear similar in patients with or without chronic kidney disease (as long as eGFR >30 mL/min/1.73 m²) 5

Given the patient's LVEF of 37%, which is very close to the guideline threshold of 35%, and the significant mortality benefit demonstrated in clinical trials, adding an MRA to the treatment regimen is appropriate to improve outcomes.