Urinary Composition during Decongestive Treatment in Heart Failure with Reduced Ejection Fraction Verbrugge et al: Urinary Composition During Decongestive Treatment

Background—The urinary composition including sodium (Na) and chloride (Cl) concentrations might provide useful information in addition to urine output during decongestive treatment in heart failure (HF). Methods and Results—Consecutive HF patients (n=61) with ejection fraction 45%, worsening symptoms, and scheduled treatment with intravenous loop diuretics were included. Patients received protocol-driven therapy until decongestion, assessed clinically and by echocardiography. Three consecutive 24h urinary collections were performed. With 2 mg (1-4 mg), 1 mg (0-2 mg), and 1 mg (0-1 mg) bumetanide administered in bolus during consecutive 24h-intervals, in addition to combinational diuretic therapy in ~70% and oral spironolactone and vasodilators both in ~90%, euvolemia was reached, often within 24h. Urine output was higher during the first compared to second/third 24h-interval (2,700 versus 1,550/1,375 mL; P-value<0.001), but this was no longer significant after correction for diuretic dose (P-value=0.263), indicating preserved diuretic efficiency during the study. In contrast, urinary Na and Cl excretion both decreased significantly, even after correction for diuretic dose (P-value=0.040 and 0.004, respectively), leading to decreasing urinary concentrations with progressive decongestion. After reaching euvolemia, a lower urinary Na/Cr and Cl/Cr ratio were both associated with urine output 1,500 mL (AUC=0.830 and 0.826, respectively; P-value<0.001 for both), in contrast to plasma NT-proBNP levels which was not (AUC=0.515; P-value=0.735) Conclusions—The urinary composition during progressive decongestion in HF with reduced ejection fraction is characterized by a drop in urinary Na and Cl concentrations. The urinary Na/Cr or Cl/Cr ratio might provide insightful information to titrate diuretic therapy.