Adding High-Dose Spironolactone to Tolvaptan Improves Acute Decompensated Heart Failure Due to Obstructive Hypertrophic Cardiomyopathy and Aortic Stenosis: A Case Report

: BACKGROUND In the setting of acute decompensated heart failure (ADHF), tolvaptan, a selective V₂ receptor antagonist, did not alter plasma renin activity or angiotensin II level, but significantly increased plasma aldosterone by the activation of V₁ₐ receptor, suggesting that a high-dose mineralocorticoid receptor antagonist (MRA) combined with a V₂ receptor antagonist might be of interest, especially in ADHF patients. However, in the setting of ADHF, the short-term and long-term efficacy of a high-dose MRA combined with tolvaptan remains unclear. CASE REPORT An 86-year-old woman with a history of chronic HF with a preserved ejection fraction due to obstructive hypertrophic cardiomyopathy and severe aortic stenosis was transferred to our hospital complaining of persistent dyspnea (New York Heart Association class IV). She did not respond to standard therapy with tolvaptan (15.0 mg/day). However, the present case demonstrated that adding high-dose spironolactone (100 mg/day) to low-dose tolvaptan (15.0 mg/day) is safe and well tolerated, resulting in an increase in urine output and improvement of the symptoms or signs of ADHF in a patient who was refractory to loop diuretics and tolvaptan. CONCLUSIONS The short- and long-term efficacy of high-dose spironolactone combined with low-dose tolvaptan may be associated with an attenuation of the aldosterone level, which is increased through V₁ₐ activation by vasopressin during tolvaptan administration.