Spot Urinary Sodium Concentration [Una+] in Acute Heart Failure with Renal Dysfunction

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Miñana G, Llàcer P, Sanchis I, García-Blas S, Bonanad C, Ventura S, Sánchez R, de la Espriella R, Bodi V, Fácila L, Mollar A, Sanchís J, Bayés-Genís A, Chorro FJ, Núñez J (on behalf of IMPROVE-HF Investigators): Early Spot Urinary Sodium and Diuretic Efficiency in Acute Heart Failure and Concomitant Renal Dysfunctioncy. Cardiorenal Medicine DOI 10.1159/000508178


Acute decompensated heart failure (AHF) is commonly associated with renal functional impairment and diuretic resistance. The assessment of “spot” [Una+] may be useful in identifying diuretic resistance and the need for high-dose therapies.

Miñana and colleagues conducted a post hoc examination of data acquired in the IMPROVE-HF trial (an RCT designed to study the benefit of usual loop-diuretic therapy vs. a carbohydrate 125-guided approach in AHF). [Una+] was measured early in 160 patients with AHF and an estimated glomerular filtrate rate (eGFR) of <60 mL/min/1.73 m2. The left ventricular ejection fraction (LVEF) was <50% in 47% and the mean aminoterminal fraction of the brain natriuretic peptide (NT-proBNP) was 7,765 pg/mL. The mean eGFR was 34 mL/min/1.73 m2 and the [Una+] was 90 mM/L; most of the patients had received low doses of furosemide or equivalent previously (time undetermined). The diuretic efficiency was assessed by the milliliters of fluid excreted per 40 mg of furosemide equivalent.

A positive relationship between diuretic efficiency and [Una+] was noted. Values of [Una+] <90 mM/L were most often accompanied by diuretic resistance. The serum sodium concentration was positively associated with [Una+]. As expected, a low serum sodium concentration (hyponatremia) was a predictor of poor outcome in AHF, as was low [Una+]. Interestingly, reduced eGFR did not predict [Una+] or diuretic resistance.

Despite the post hoc design of this study, it offers support for the utility of early “spot” [Una+] in defining the prognosis and predicting the likelihood of diuretic resistance in AHF, regardless of the concomitant presence of impaired renal function. Obviously, this study does not apply to stable chronic HF or patients with established CKD and concomitant HF. A prospective study is needed to confirm these findings.


Richard Glassock


Quoted Karger Article

Early Spot Urinary Sodium and Diuretic Efficiency in Acute Heart Failure and Concomitant Renal Dysfunction