What is the recommended treatment for a patient with heart failure with reduced ejection fraction, considering Angiotensin Receptor-Neprilysin Inhibitor (ARNI) therapy?

ARNI (Angiotensin Receptor-Neprilysin Inhibitor) Therapy for Heart Failure with Reduced Ejection Fraction

Sacubitril/valsartan (ARNI) should replace ACE inhibitors or ARBs in all symptomatic HFrEF patients (NYHA class II-IV, EF ≤40%) as part of foundational quadruple therapy, providing superior mortality reduction of at least 20% compared to enalapril. 1, 2

Core Indication and Patient Selection

ARNI is indicated for patients with:

• Heart failure with reduced ejection fraction (EF ≤40%) 1, 3
• NYHA functional class II-IV symptoms 1, 3
• Administered in conjunction with guideline-directed medical therapy (beta-blockers, mineralocorticoid receptor antagonists, SGLT2 inhibitors) 1, 2

Critical point: You do NOT need to wait for patients to "fail" optimal medical therapy first—all HFrEF patients on ACE inhibitors or ARBs are candidates for switching to ARNI, even with mild symptoms. 2

Clinical Benefits: Why ARNI is Superior

The PARADIGM-HF trial demonstrated that sacubitril/valsartan reduced:

• Cardiovascular death by 20% compared to enalapril 1, 4
• Heart failure hospitalization significantly 1, 5
• All-cause mortality 5

Additional benefits beyond mortality:

• Median LVEF increased from 28.2% to 37.8% after 12 months (9.4% improvement) 1
• Left ventricular end-diastolic volume index decreased by 12.25 mL/m² 1
• Improvements in diastolic function, quality of life, and ventricular arrhythmia burden 1

Practical Dosing Algorithm

Starting Dose Selection 1, 2, 3

Standard patients (previously on high-dose ACE inhibitor):

• Start 49/51 mg twice daily 1, 3

High-risk patients—start 24/26 mg twice daily if:

• Not currently on ACE inhibitor/ARB or on low doses 1, 3
• Severe renal impairment (eGFR <30 mL/min/1.73 m²) 1, 3
• Moderate hepatic impairment (Child-Pugh B) 1, 2
• Age ≥75 years 2
• Systolic blood pressure <100 mmHg (though not absolute contraindication) 2

Titration Schedule 2, 6

• Double the dose every 2-4 weeks as tolerated 1, 2
• Target maintenance dose: 97/103 mg twice daily 1, 3
• Both condensed (3 weeks) and gradual (6 weeks) titration approaches are similarly tolerated, but gradual maximizes target dose attainment 1

Switching from ACE Inhibitor or ARB: Critical Safety Steps

From ACE inhibitor to ARNI:

• MANDATORY 36-hour washout period to avoid angioedema 1, 3, 5
• This delay is strictly required and non-negotiable 1

From ARB to ARNI:

• No washout period required—can switch immediately 1, 2

Common pitfall: Failure to observe the 36-hour washout when switching from ACE inhibitors is a serious safety error that increases angioedema risk. 1

Managing Barriers to Optimal Dosing

Hypotension Management 2, 6

Asymptomatic hypotension (SBP 90-100 mmHg with adequate perfusion):

• Do NOT reduce or discontinue ARNI 2, 6
• ARNI maintains efficacy and safety even with baseline SBP <110 mmHg 2
• Patient education about transient dizziness improves compliance 6

Symptomatic hypotension (SBP <80 mmHg or major symptoms):

1. Address reversible non-HF causes first: stop alpha-blockers (tamsulosin), discontinue non-essential BP-lowering medications, evaluate for dehydration/infection 6
2. Non-pharmacological interventions: compression leg stockings, exercise programs, adequate salt/fluid intake if not volume overloaded 6
3. If symptoms persist: reduce diuretic dose first in non-congested patients 2
4. Only as last resort: temporarily reduce ARNI dose, then re-titrate when stable 2

Renal Function Changes 6

• Modest creatinine increases (up to 30% above baseline) are acceptable and should NOT prompt discontinuation 6
• Monitor renal function at 1-2 weeks after each dose increment 6
• Discontinuing RAAS inhibitors after renal changes is associated with 2-4 fold higher risk of adverse events 6

Hyperkalemia 6

• Monitor potassium closely, especially with concurrent mineralocorticoid receptor antagonists 6
• Consider potassium binders (patiromer) rather than discontinuing life-saving medications 6
• ARNI actually reduces hyperkalemia risk compared to ACE inhibitor plus MRA combinations 6

Absolute Contraindications 3

• History of angioedema related to previous ACE inhibitor or ARB therapy 3
• Concomitant use with ACE inhibitors (requires 36-hour washout) 3
• Concomitant use with aliskiren in patients with diabetes 3
• Pregnancy (discontinue immediately when detected) 3
• Hypersensitivity to any component 3

Common Prescribing Pitfalls to Avoid

1. Delaying initiation while waiting for aldosterone antagonist—lack of MRA should NOT delay ARNI therapy 1
2. Accepting suboptimal doses due to asymptomatic hypotension—target doses provide maximum mortality benefit 2, 6
3. Permanent dose reductions when temporary reductions with subsequent re-titration would be appropriate 2
4. Inadequate monitoring of blood pressure, renal function, and electrolytes during titration 6
5. Treating HF less aggressively than other life-threatening conditions despite similar mortality risks 2

Place in Modern HFrEF Treatment Algorithm 2, 6

Foundational quadruple therapy (start simultaneously):

1. SGLT2 inhibitor (dapagliflozin or empagliflozin) 2, 6
2. Mineralocorticoid receptor antagonist (spironolactone or eplerenone) 2, 6
3. Beta-blocker (carvedilol, metoprolol succinate, or bisoprolol) 2, 6
4. ARNI (sacubitril/valsartan) as replacement for ACE inhibitor/ARB 2, 6

Titration priority: Start SGLT2 inhibitor and MRA first (minimal BP effects), then add beta-blocker, then ARNI. 2, 6

This combination provides approximately 73% mortality reduction over 2 years and 5.3 additional life-years compared to no treatment. 6