What is the next best step in managing hyperkalemia in a patient with heart failure and chronic kidney disease?

Management of Hyperkalemia in Heart Failure with Reduced Ejection Fraction and Chronic Kidney Disease

The next best step is to discontinue spironolactone (the mineralocorticoid receptor antagonist) while continuing furosemide (Lasix), as the patient has moderate hyperkalemia (potassium 5.9 mEq/L) with significantly elevated creatinine (1.9 mg/dL), and temporarily stopping the MRA allows for potassium reduction while maintaining diuresis. 1

Severity Classification and Immediate Management

This patient has moderate hyperkalemia (potassium 5.9 mEq/L), which falls into the 5.6-5.9 mEq/L range requiring intervention but not necessarily emergent treatment. 1

• The European Society of Cardiology guidelines specify that for potassium levels between 5.0-6.5 mEq/L in patients on maximum-tolerated RAAS inhibitor doses, potassium-lowering therapy should be initiated while closely monitoring levels. 1
• For moderate hyperkalemia (5.6-5.9 mEq/L), RAAS inhibitors should be temporarily discontinued until potassium decreases to <5.0 mEq/L or returns to the patient's usual range, whichever is higher. 1

Why Discontinue Spironolactone Specifically

Spironolactone (the mineralocorticoid receptor antagonist) is the primary culprit and should be stopped first, not furosemide (Lasix). 1

• Mineralocorticoid receptor antagonists are the most common RAAS inhibitor requiring discontinuation for hyperkalemia, with 35.1% of patients unable to use MRAs due to elevated potassium compared to only 8.5% for ACE inhibitors/ARBs. 1
• The European Society of Cardiology recommends discontinuing MRAs when potassium levels rise >5.0 mmol/L in the acute setting. 1
• Loop diuretics like furosemide actually help lower potassium by increasing renal potassium excretion and should be continued or even increased in dose. 1

Why Not the Other Options

Continuing furosemide is appropriate because loop diuretics enhance potassium elimination through increased renal excretion. 1

Sodium bicarbonate is not indicated as the primary intervention because:

• It is reserved for acute, life-threatening hyperkalemia (typically >6.5 mEq/L) with ECG changes, used to shift potassium intracellularly temporarily. 1
• Bicarbonate only provides temporary benefit (1-4 hours) without increasing potassium excretion, and rebound hyperkalemia can occur. 1
• This patient's potassium of 5.9 mEq/L does not meet criteria for emergent treatment unless ECG changes are present. 1

Substituting eplerenone for spironolactone is not appropriate because:

• Both are mineralocorticoid receptor antagonists with similar potassium-retaining effects. 1
• The issue is the drug class itself in the context of CKD (creatinine 1.9) and moderate hyperkalemia, not the specific MRA agent. 1

Algorithmic Approach to This Clinical Scenario

Step 1: Assess severity and need for emergent treatment

• Potassium 5.9 mEq/L = moderate hyperkalemia (not immediately life-threatening unless ECG changes present). 1

Step 2: Identify contributing medications

• Spironolactone is the primary potassium-retaining agent in this patient. 1
• Review for other contributing drugs (NSAIDs, potassium supplements, salt substitutes). 2

Step 3: Temporarily discontinue the MRA

• Stop spironolactone until potassium <5.0 mEq/L. 1
• Continue furosemide to maintain diuresis and enhance potassium excretion. 1

Step 4: Monitor and plan for reinitiation

• Recheck potassium and creatinine within 2-4 weeks. 1
• Once potassium <5.0 mEq/L and any acute contributing factors are controlled, consider reintroducing RAAS inhibitors one at a time with close monitoring. 1

Long-Term Management Considerations

After acute stabilization, strategies to maintain guideline-directed medical therapy should be considered:

• Adding an SGLT2 inhibitor reduces hyperkalemia risk by 16% (HR 0.84) while providing mortality benefit in heart failure. 2
• Potassium binders (patiromer or sodium zirconium cyclosilicate) can enable continuation of high-dose RAAS inhibitors in patients with recurrent hyperkalemia. 1, 2, 3
• Switching to sacubitril/valsartan reduces severe hyperkalemia by 27-37% compared to ACE inhibitors in patients requiring MRAs. 2

Critical Pitfalls to Avoid

• Do not discontinue furosemide - loop diuretics help eliminate potassium and maintain euvolemia. 1
• Do not permanently abandon RAAS inhibitors - temporary discontinuation with planned reinitiation is preferred over permanent withdrawal, as GDMT improves mortality in HFrEF. 2
• Do not use sodium polystyrene sulfonate (Kayexalate) chronically due to risk of bowel necrosis and lack of efficacy data. 2
• Monitor closely after reinitiation - check potassium at 1,4,8, and 12 weeks after restarting spironolactone. 2