Echocardiography versus Bioimpedance in Evaluating Volume Status in Patients with Chronic Cardiorenal Syndrome: A Preliminary Study.

Abstract

Background and aim: Assessment of volume status plays a critical role in the therapeutic management of patients with heart failure (HF) and chronic kidney disease (CKD). Echocardiography and bioelectrical impedance analysis (BIA) are two noninvasive methods frequently used to evaluate body fluid distribution. This study aimed to investigate the correlation between parameters obtained from these two methods in hospitalized patients.

Methods: In this cross-sectional study, 40 patients with concurrent HF and CKD admitted to a tertiary hospital were evaluated. Demographic data, medical history, medication usage, and echocardiographic and BIA parameters were collected. Associations between variables were analyzed using correlation and regression models, with statistical significance defined as P < 0.05.

Results: A significant correlation was found between inferior vena cava diameter and total body water (TBW) (ρ = 0.332, P = 0.037). Reduced left ventricular ejection fraction (EF) was associated with increased left atrial volume (LAV) and LAV index (P < 0.001). Among echocardiographic indices, right ventricular diameter showed strong positive correlations with TBW (ρ = 0.610, P < 0.001), intracellular water (ρ = 0.597, P < 0.001), and extracellular water (ECW) (ρ = 0.571, P < 0.001). E-wave velocity correlated positively with ECW ratio (ρ = 0.434, P = 0.005) and negatively with segmental phase angle (ρ = -0.398, P = 0.011). Patients with pulmonary congestion on computed tomography had lower segmental phase angle values (P = 0.027), and those with pleural effusion showed higher ECW ratios (P = 0.047). However, no significant correlations were observed between systolic pulmonary artery pressure (SPAP), tricuspid regurgitation gradient, and BIA-derived indices. Among laboratory markers, serum creatinine was significantly associated with the body cell mass index (P = 0.049), whereas NT-proBNP and CA125 were not. Clinically, patients with lower limb edema had higher ECW ratios (P = 0.045), and those with pulmonary rales exhibited lower stroke volume index (SVI) values (P = 0.027).

Conclusion: The findings suggest that echocardiography and BIA provide complementary insights into volume assessment in patients with HF and CKD. Significant correlations between selected parameters indicate that combining these modalities may enhance diagnostic accuracy. However, further large-scale studies are warranted to validate the clinical utility of these findings.