Hyponatremia in patients with heart failure

Abstract

The present review analyses the mechanisms relating heart failure and hyponatremia, describes the association of hyponatremia with the progress of disease and morbidity/mortality in heart failure patients and presents treatment options focusing on the role of arginine vasopressin (AVP)-receptor antagonists. Hyponatremia is the most common electrolyte disorder in the clinical setting and in hospitalized patients. Patients with hyponatremia may have neurologic symptoms since low sodium concentration produces brain edema, but the rapid correction of hyponatremia is also associated with major neurologic complications. Patients with heart failure often develop hyponatremia owing to the activation of many neurohormonal systems leading to decrease of sodium levels. A large number of clinical studies have associated hyponatremia with increased morbidity and mortality in patients hospitalized for heart failure or outpatients with chronic heart failure. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. AVP-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia. However, the effects of AVP-receptor antagonists on hard outcomes in patients with heart failure and hyponatremia have not been thoroughly examined.

Keywords: Heart failure, Hyponatremia, Sodium, Vasopressin, Vasopressin-receptor antagonists, Tolvaptan, Conivaptan, Lixivaptan

Core tip: Patients with heart failure and hyponatremia have increased morbidity and mortality compared with subjects with normal sodium levels. Established treatment options for hyponatremia in heart failure such as fluid restriction or the use of hypertonic saline with loop diuretics have limited efficacy and compliance issues. Arginine vasopressin (AVP)-receptor antagonists increase sodium levels and exhibit beneficial effects on hemodynamic variables in patients with heart failure. However, double-blind, placebo-controlled trials examining the effects of AVP-receptor antagonists on mortality, quality of life and length of hospital stay in patients with heart failure and hyponatremia are missing.