Clinical course of patients with hyponatremia and decompensated systolic heart failure and the effect of vasopressin receptor antagonism with Tolvaptan

Background: Patients with decompensated heart failure, volume overload, and hyponatremia are challenging to manage. Relatively little has been documented regarding the clinical course of these patients during standard in-hospital management or with vasopressin antagonism. Methods and Results: The Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study With Tolvaptan database was examined to assess the short-term clinical course of patients hospitalized with heart failure and hyponatremia and the effect of tolvaptan on outcomes. In the placebo group, patients with hyponatremia (serum Na⁺ <135mEq/L; n = 232), compared with those with normonatremia at baseline (n = 1785), had less relief of dyspnea despite receiving higher doses of diuretics (59.2% vs 69.2% improved; P <.01) and worse long-term outcomes. In the hyponatremia subgroup from the entire trial cohort (n = 475), tolvaptan was associated with greater likelihood of normalization of serum sodium than placebo (58% vs 20% and 64% vs 29% for day 1 and discharge, respectively; P <.001 for both comparisons), greater weight reduction at day 1 and discharge (0.7 kg and 0.8 kg differences, respectively; P <.001 and P =.008), and greater relief of dyspnea (P =.03). Among all hyponatremic patients, there was no effect of tolvaptan on long-term outcomes compared with placebo. In patients with pronounced hyponatremia (<130 mEq/L; n = 92), tolvaptan was associated with reduced cardiovascular morbidity and mortality after discharge (P =.04). Conclusions: In patients with decompensated heart failure and hyponatremia, standard therapy is associated with less weight loss and dyspnea relief, and unfavorable longer-term outcomes compared to those with normonatremia. Tolvaptan is associated with more favorable in-hospital effects and, possibly, long-term outcomes in patients with severe hyponatremia.