SummaryHypervolemic hyponatremia is often complicated with advanced heart failure together with increased excretion of sodium by diuretics. Tolvaptan, an oral vasopressin-2-receptor antagonist, has been previously reported to improve congestion and correct hyponatremia through increased excretion of free water. However, there is little evidence concerning the administration of tolvaptan in patients with stage D heart failure. We experienced 2 patients with stage D heart failure who received 3.75 mg/day of tolvaptan to correct hyponatremia before ventricular assist device implantation. It may be useful, even for patients with stage D heart failure, to administer a low dose of tolvaptan to treat hyponatremia before ventricular assist device implantation to avoid a drastic alteration in serum sodium concentration perioperatively. (Int Heart J 2012; 53: 391-393) Key words: Osmotic demyelination syndrome, Arginine vasopression, Heart failure H yponatremia, which is generally defined as serum sodium of < 135 mEq/L, 1) is a common electrolyte disorder among hospitalized patients and is associated with increased mortality.2) In patients with congestive heart failure, hypervolemic hyponatremia results from water retention, by way of increases in arginine vasopression (AVP) levels and/or decreases in glomerular filtration.3) In patients with stage D heart failure in particular, almost all patients cannot help depending on diuretics, which facilitate hyponatremia due to increased excretion of sodium and stimulation of renin/angiotensin and norepinephrine secretion as well as inappropriate AVP secretion against low or normal serum osmolality. 4) We here experienced 2 patients with stage D heart failure, who were in progressive decline with severe hyponatremia despite optimal medication and intravenous catecholamine infusion. Since both patients were indicated for left ventricular assist device (LVAD) implantation, we were afraid that osmotic demyelination syndrome (ODS) would emerge after rapid correction of hyponatremia through stabilization of hemodynamic state after surgery. 5) To avoid this, we administered 3.75 mg/day of tolvaptan, an oral vasopressin-2-receptor antagonist, to treat their hyponatremia preoperatively.
Case ReportThe first patient was a 33-year-old male with dilated cardiomyopathy (DCM) (Figure 1, Table). He became dependent upon intravenous dobutamine in August 2010 despite administration of maximum medical therapy including pimobendan, carvedilol, furosemide, spironolactone, and enalapril. Cardiac resynchronization therapy with a defibrillator could not help worsening of his heart failure and he was transferred to our hospital to consider VAD therapy in January 2011. His serum sodium level was 123 mEq/L, serum creatinine level was 0.81 mg/dL, and B-type natriuretic peptide level was 1707 pg/mL on his admission. Right catheterization showed that mean right atrial (RA) pressure was 12 mmHg, left ventricular end-diastolic pressure was 38 mmHg, and cardiac index (CI) was 1.7 L/ minute/m 2 . Administrat...