The independent association between altered renal arterial resistance and loop diuretic dose in chronic heart failure outpatients

BACKGROUND In chronic heart failure (CHF) patients there is a wide variability in the minimal effective diuretic dose. The aim of this study is to evaluate whether renal resistance index (RRI) is associated to baseline diuretic dose and the changes at one year. METHODS AND RESULTS 250 outpatients in a stable condition and in conventional therapy were enrolled. Baseline RRI was calculated by renal arterial Doppler. The total daily dose of loop diuretics was assessed at baseline and after one year. High diuretic dose (HDD) was defined as a daily furosemide equivalent dose > 100 mg. RRI was independently associated with baseline HDD at univariate (OR 1.39; 95% CI: 1.233-1.58; p < 0.001) and multivariate analysis (OR 1.27; 95% CI: 1.09-1.49; p: 0.002) after correction for other univariate predictors (age, NYHA class, left ventricular ejection fraction, tricuspid annulus peak of systolic excursion, NT-proBNP, glomerular filtration rate by EPI formula and central venous pressure). Moreover, baseline RRI was independently associated to one year stable increase in loop diuretic dose at univariate and multivariate regression analyses. CONCLUSIONS RRI is independently associated with high dose loop diuretics and their increase during a mid-term follow-up thus suggesting its usefulness in detecting an altered diuretic response in CHF outpatients.