A 67-year-old man with nonischemic cardiomyopathy comes to the office for follow-up. He recently was hospitalized for acute decompensated heart failure. The patient's symptoms have improved with multidrug treatment, but he has persistent shortness of breath on mild exertion. He has a history of hypertension and hypercholesterolemia. Blood pressure is 115/70 mm Hg and pulse is 66/min. There is a third heart sound on heart auscultation and mild lower extremity pitting edema. A recent echocardiogram showed a left ventricular ejection fraction of 30%. Which of the following diuretics would most likely improve survival if added to this patient's current regimen?
Mineralocorticoid receptor antagonists (eg, spironolactone, eplerenone) prevent aldosterone from binding to its receptor in the distal renal tubules. This leads to increased sodium and water excretion while conserving potassium ions (potassium-sparing diuresis). These antagonists also block the deleterious effect of aldosterone on the heart, causing regression of myocardial fibrosis and improvement in ventricular remodeling.
Mineralocorticoid receptor antagonists reduce morbidity and improve survival in patients with congestive heart failure and decreased ejection fraction. Therefore, they are recommended in addition to standard heart failure therapy (ACE inhibitors and beta blockers). They should not be used in patients with hyperkalemia or renal failure. The most common side effects are hyperkalemia and gynecomastia (spironolactone >> eplerenone).
(Choices A, C, and F) Acetazolamide (carbonic anhydrase inhibitor), hydrochlorothiazide (thiazide diuretic), and triamterene (epithelial sodium channel blocker) have a variably lower diuretic effect compared to loop diuretics and are not as efficacious for treating heart failure symptoms.
(Choice B) Furosemide is a loop diuretic frequently used for treatment of pulmonary congestion and fluid retention in heart failure patients. Although loop diuretics improve symptoms significantly, they do not provide survival benefit (ie, improved morbidity but not mortality) in these patients.
(Choice D) Mannitol is an intravenous osmotic diuretic used primarily to lower intracranial pressure and treat acute glaucoma. It is not used to treat heart failure as it can cause an initial rise in extracellular fluid volume, exacerbating pulmonary congestion and peripheral fluid retention.
Educational objective:
Mineralocorticoid receptor antagonists (eg, spironolactone, eplerenone) improve survival in patients with congestive heart failure and reduced left ventricular ejection fraction. They should not be used in patients with hyperkalemia or renal failure.