A 62-year-old woman with ischemic cardiomyopathy (ejection fraction 28%) and chronic kidney disease stage 3b (eGFR 38 mL/min/1.73 m²) is on lisinopril 10 mg daily, metoprolol succinate 190 mg daily, and furosemide 40 mg daily. She remains symptomatic with NYHA class III dyspnea. Her current labs show: serum creatinine 1.8 mg/dL, potassium 4.2 mEq/L, BNP 450 pg/mL. Which of the following agents should be added to her regimen to improve mortality and reduce hospitalizations?

Explanation

## Clinical Context: Optimizing HF Therapy This patient has: - Reduced ejection fraction (HFrEF) with NYHA class III symptoms - Already on an ACE inhibitor and beta-blocker (foundational therapy) - Mild hyperkalemia risk (eGFR 38, K+ 4.2 — borderline) - Persistent symptoms despite standard therapy ### The Role of ARNI in HFrEF **Key Point:** Sacubitril/valsartan (ARNI — Angiotensin Receptor–Neprilysin Inhibitor) is superior to ACE inhibitors in reducing mortality and hospitalizations in HFrEF and is now a cornerstone of HF therapy. ### Mechanism of ARNI ```mermaid flowchart TD A[Sacubitril/Valsartan]:::action --> B[Dual Action] B --> C[Neprilysin Inhibition<br/>↑ Natriuretic peptides<br/>↓ Vasoconstriction]:::outcome B --> D[ARB Activity<br/>↓ Angiotensin II<br/>↓ Aldosterone]:::outcome C --> E[Improved Renal Perfusion<br/>Enhanced Natriuresis]:::outcome D --> E E --> F[↓ Mortality & Hospitalizations]:::outcome ``` **High-Yield:** PARADIGM-HF trial (2014) demonstrated that sacubitril/valsartan reduced mortality by 20% and HF hospitalizations by 21% compared to enalapril in HFrEF. It is now Class 2a recommendation in most guidelines for HFrEF. ### Comparison of Options | Agent | Indication | Mortality Benefit | Limitation in This Patient | |-------|-----------|-------------------|---------------------------| | **Sacubitril/valsartan (ARNI)** | HFrEF, NYHA II–IV | Yes (PARADIGM-HF) | Replaces ACE-I; requires monitoring | | Spironolactone | HFrEF + NYHA III–IV | Yes (RALES trial) | eGFR 38 + K+ 4.2 = hyperkalemia risk; already on ACE-I | | Ivabradine | HFrEF + HR ≥70 + NSR | Modest (SHIFT trial) | Not mortality-reducing; HR not elevated (88/min baseline) | | Hydralazine | Specific populations | No mortality benefit | Not indicated as add-on in this patient; reserved for African Americans or ACE-I/ARB intolerance | ### Why ARNI Is the Best Choice 1. **Superior to ACE inhibitors:** PARADIGM-HF showed ARNI superiority in reducing death and HF hospitalization 2. **Replaces, not adds to, ACE inhibitor:** Avoids dual RAAS blockade and hyperkalemia risk 3. **Guideline-recommended:** 2022 AHA/ACC/HFSA guidelines recommend ARNI as preferred agent over ACE-I/ARB in HFrEF 4. **Safe in CKD stage 3b:** eGFR 38 is acceptable; requires monitoring but not a contraindication **Clinical Pearl:** When switching from an ACE inhibitor to ARNI, discontinue the ACE inhibitor first to avoid dual RAAS blockade. Monitor potassium and creatinine at 1–2 weeks and 4 weeks post-initiation.