Urinary sodium analysis: The key to effective diuretic titration? European Journal of Heart Failure expert consensus document

Abstract

In patients with heart failure, neurohumoral activation leads to increased renal sodium avidity across the entire renal tubules, resulting in a positive sodium and water balance, leading to decompensated heart failure requiring intravenous diuretics. As the dose of diuretic therapy required to achieve euvolaemia is difficult to estimate due to considerable intra- and interindividual differences, the European Society of Cardiology recommends assessment of the diuretic response within hours either via evaluation of the urinary sodium concentration or via urinary volume after initial diuretic administration. All diuretic agents enhance sodium excretion to a different extent depending on their side of action across the renal tubules, and renal adaptation mechanisms due to neurohumoral stimulation. Impaired sodium excretion, even in the presence of fluid loss, is associated with worse clinical outcomes. Therefore, assessing urinary sodium excretion is considered a good and direct marker of the diuretic efficacy. Such natriuresis-guided protocols have been tested prospectively by the Pragmatic Urinary Sodium-based algoritHm in Acute Heart Failure and the Efficacy of a Standardized Diuretic Protocol in Acute Heart Failure study, both demonstrating increased natriuresis and diuresis. Moreover, the Readily Available Urinary Sodium Analysis in Patients with Acute Decompensated Heart Failure study has demonstrated that a nurse-led natriuresis-guided protocol is feasible through the use of a point-of-care urinary sodium sensor, allowing an immediately readable urinary sodium result, enabling fast changes in diuretic therapy. This review summaries the rationale, current evidence and gaps supporting the role of urinary sodium concentration in patients with acute decompensated heart failure.