Natriuresis level as a marker of the diuretic therapy effectiveness and a predictor of an adverse outcome in patients with acute decompensated chronic heart failure

Aim . To evaluate the role of natriuresis as a marker of the effectiveness of diuretic therapy and a predictor of adverse outcome in patients with acute decompensated heart failure (ADHF). Material and methods . The single-center prospective study included 155 patients hospitalised with ADHF in the intensive care unit (mean age 71.9±11.9 years, men 56%). All patients underwent standard physical, laboratory, and instrumental examinations in the first 24 hours, including clinical assessment of congestion, N-terminal pro-brain natriuretic peptide, lung ultrasound, venous congestion assessment according to the Venous Excess Ultrasound (VExUS) protocol, and renal function assessment (creatinine, cystatin C, and urinary albumin/creatinine). An instrumental assessment of congestion (ultrasound of the lungs, venous congestion according to the VExUS protocol), as well as an assessment of renal function (creatinine, urinary albumin/creatinine ratio) was performed after 48, 72 hours and before discharge. The starting dose of furosemide was 20-40 mg IV if patients did not receive oral diuretics, if they did, the starting dose was equal to the oral dose. After 2 hours, a quantitative assessment of sodium in urine was performed. If natriuresis level was ≥70 mmol/L, furosemide was continued at the same dose every 12 hours; if <70 mmol/L, the furosemide dose was doubled. Urine sodium concentration was monitored every 12 hours. Long-term clinical outcomes were assessed via structured telephone interviews at 90, 180, and 365 days post-discharge. The primary endpoint was a composite of all-cause death and rehospitalisation for ADHF. Results . Patients with natriuresis <70 mmol/l, compared to those with ≥70 mmol/l, were characterised by more pronounced manifestations of congestion in both circulatory circles (B lines 35 versus 30, p<0.05; the frequency of venous congestion according to the VExUS protocol 69.4% versus 34.3%, p<0.001), significantly higher levels of N-terminal pro-brain natriuretic peptide (2504 pg/ml versus 1675 pg/ml, p<0.01), with a higher incidence of acute renal injury (71.1% versus 40.6%, p<0.001). Against the background of diuretic therapy in patients with natriuresis < 70 mmol/l, despite an increase in the dose of furosemide, there is a significantly worse response to diuretic therapy, lower values of daily diuresis, as well as a significantly less pronounced decrease in congestion, both according to lung ultrasound and according to the VExUS protocol. Conclusion . Natriuresis <70 mmol/L is a predictor of adverse outcomes in patients with ADHF during 1 year of follow-up and allows us to identify the most severe group of patients with a high risk of resistance to diuretic therapy.