The utility of inferior vena cava diameter and the degree of inspiratory collapse in patients with systolic heart failure

Abstract

Introduction: Both inferior vena cava (IVC) diameter and the degree of inspiratory collapse are used in the estimation of right atrial pressure. Aim: The purpose of this study is to evaluate the utility of IVC diameter, using echocardiography as a marker of volume overload and the relationship between these parameters and N-terminal pro-B natriuretic peptide (NT-proBNP) in patients with systolic heart failure (HF). Methods: We included 136 consecutive patients with systolic HF (left ventricular ejection fraction, <50%), including 80 patients with acutely decompensated HF and 56 patients with compensated HF as well as 50 subjects without a diagnosis of HF. All patients underwent transthoracic echocardiography to assess both their IVC diameters and the degree of inspiratory collapse (>= 50%, <50%, and no change [absence] groups); NT-proBNP levels were measured, and these data were compared between the 2 groups. Results: Inferior vena cava diameter and NT-proBNP were significantly higher among the patients with HF than among the control subjects (21.7 +/- 2.6 vs 14.5 +/- 1.6 mm, P < .001 and 4789 [330-35000] vs 171 [21-476], P < .001). The mean IVC diameter was higher among the patients with decompensated HF than among the patients with compensated HF (23.2 +/- 2.1 vs 19.7 +/- 1.9 mm, P < .001). The values of NT-proBNP were associated with different collapsibility of IVC subgroups among HF patients. The NT-proBNP levels were 2760 (330-27336), 5400 (665-27210), and 16806 (1786-35000), regarding the collapsibility of the IVC subgroups: greater than or equal to 50%, less than 50%, and absence groups, P < .001, respectively, among HF patients. There was a significant positive correlation between IVC diameter and NT-proBNP (r = 0.884, P < .001). A cut off value of an IVC diameter greater than or equal to 20.5 mm predicted a diagnosis of compensated HF with a sensitivity of 90% and a specificity of 73%. Conclusions: Inferior vena cava diameter correlated significantly with NT-proBNP in patients with HF. Inferior vena cava diameter may be a useful variable in determining a patient's volume status in the setting of HF and may also enable clinicians to distinguish patients with decompensated HF from those with compensated HF.