Ultrasound evaluation of the inferior vena cava collapsibility index in congestive heart failure patients treated with intravenous diuretics: new insights about its relationship with renal function: an observational study.

OBJECTIVE In chronic heart failure (CHF), collapsibility index of the inferior vena cava (IVCCI) is used for noninvasive ultrasonographic appraisal of central venous pressure, but it also may be related both to estimated glomerular filtration rate (eGFR) and renal outcome. METHODS On the basis of retrospective observational cohort study, we analyzed 49 patients with right or biventricular CHF in III NYHA class, who had undergone intravenous intensive treatment with furosemide. Aggravated renal dysfunction (ARD) was defined by serum creatinine (Cr) increase of ≥0.3 mg/dL from baseline. IVCCI was categorized in three layers (IVCCI ≤15%, IVCCI 16-40% and IVCCI >40%). The predictors of ARD were searched for as well as any relation between basal IVCCI and both eGFR at admission and occurrence of ARD. RESULTS Overall, 15 cases and 34 controls were compared. Multivariate predictors of ARD were a lower basal eGFR (HR: 0.82 CI: 0.72-0.94 p=0.0045) and intravenous furosemide daily mean dose >80 mg (HR: 48.62 CI: 1.62-3841.5 p=0.0430). A very significant positive correlation was found between IVCCI at admission ≤ 15% and basal eGFR (r=0.96 p<0.0001), while a negative correlation with eGFR was detected in the IVCCI highest (>40%) range (r=-0.696 p=0.0013). Furthermore, the category with basal IVCCI >40% showed a higher rate of ARD compared to that with basal IVCCI 16-40% (p<0.05). CONCLUSION On the basis of the demonstrated u-shaped relationship between IVCCI and eGFR both the stratum with the highest (>40%) and the one with the lowest (≤15%) basal IVCCI may be associated with increased risk of ARD.