Impact of diuretic treatment and sodium intake on plasma volume in patients with compensated systolic heart failure

Abstract

Aims In patients with heart failure (HF), the use of diuretics may be a double-edged sword that can alleviate symptoms of congestion, but also result in over-diuresis and intravascular volume depletion. The purpose of the present study was to examine plasma volume (PV) in HF patients receiving from 0 to 160 mg of furosemide and to investigate whether determination of plasma N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) concentrations can predict PV-status. Methods and results Plasma volume, extracellular volume, glomerular filtration rate, NT-proBNP, and daily renal sodium excretion were measured in 18 patients with medically treated, compensated HF and in 27 healthy volunteers. Cardiac function was examined by non-invasive cardiac output determination and echocardiography. Exercise capacity was evaluated by 6 min walk test. There was a borderline significant difference in PV between patients with HF and control subjects (37.3 ± 6.0 and 40.2 ± 5.8 mL/kg, respectively, P = 0.092) with a significant tendency towards a contraction of PV with increasing use of diuretics (P = 0.031). There was no difference in extracellular volume between patients with HF and control subjects (P = 0.844). NT-proBNP plasma concentrations had no correlation to either sodium excretion (P = 0.193) or PV (P = 0.471) in patients with HF. ConclusionPlasma volume in patients with HF was within normal limits, but patients treated with high doses of loop-diuretics tended to have subnormal PV. Single measurement of NT-proBNP plasma concentration could not be used to estimate intravascular volume status in patients with HF. © 2010 The Author.