Natriuresis as a Way to Assess the Effectiveness of Diuretic Therapy for Acute Decompensated Heart Failure: Data from a Pilot Study

Abstract

Aim. To analyze the clinical significance of the sodium level in a single urine test obtained 2 hours after the first dose of a loop diuretic was administered in patients with acute decompensation of chronic heart failure (ADHF).Material and methods. An observational study was conducted on the basis of a rapid-care hospital. The concentration of sodium in urine analysis obtained 2 hours after intravenous administration of the first dose of loop diuretic and natriuresis for the first day of hospitalization were evaluated. The development of resistance to diuretics was taken as the primary endpoint (the need to increase the daily dose of furosemide by more than 2 times compared to the initial one or the addition of another class of diuretic drugs).Results. 25 patients with ADHF were included. The average age of patients was 69.0±14.8 years, 16 (64%) of them were men. The average left ventricular ejection fraction was 49.0±13.5%. The level of the N‐terminal fragment of the brain natriuretic peptide (NT-proBNP) was 3416 (2128; 5781) pg/ml. The average sodium concentration in the urine analysis obtained 2 hours after the start of treatment was 100.6±41.0 mmol / l. The concentration of sodium in urine for the first day was 102.2±39.0 mmol/l. 2 hours after the start of treatment, the sodium concentration in a single urine test was less than 50 mmol/l in 5 (20%) patients. Upon further observation, oligoanuria (defined as diuresis of less than 400 ml within 24 hours) developed in 2 of them. Oligoanuria was not detected among patients whose sodium concentration was more than 50 mmol/l. The need for escalation (any increase in the dose of a loop diuretic and/or the addition of another class of diuretic drugs) arose in 7 (28%) patients; at the same time, we diagnosed the development of resistance to diuretics in 5 (20%) of them. Resistance to diuretics was more common among patients with a sodium concentration in a single urine test obtained 2 hours after the start of furosemide administration, less than 50 mmol/l (p=0.037); when dividing the recruited patient population into subgroups with a sodium concentration in a single urine test ≥50 mmol/l and <50 mmol/l there was no significant difference in the need for any escalation of diuretic therapy [3 (60%) vs 4 (20%), p=0.07].Conclusion. Resistance to diuretics is more common among patients with a sodium concentration in a single urine test obtained 2 hours after the first dose of furosemide, less than 50 mmol / l. Evaluation of natriuresis allows to identify insufficient effectiveness of diuretic therapy already at the beginning of treatment.