Bioimpedance-derived compartmental fluid status and prognosis in chronic heart failure

Novel bioimpedance analysis (BIA) devices may improve the precision of fluid overload assessment, potentially offering additional prognostic information beyond clinical parameters in patients with HF. This study aimed to evaluate the association between fluid overload indexes obtained with a novel bioelectrical impedance device (BioScan touch i8 IVF, MALTRON®) and the risk of cardiovascular events in ambulatory patients with HF.

Volume excess was assessed using BioScan Touch i8 IVF (MALTRON), which differentiates fluid distribution across body compartments. Volume-excess variables (total, intravascular, and tissue) were analysed both as quartiles (Q) and as continuous measures. Their independent associations with the composite of all-cause death or worsening HF were adjusted for established prognostic markers, including a clinical congestion score (CCS) and N-terminal pro-B-type natriuretic peptide.

Among 386 ambulatory patients with stage C chronic HF, median total, intravascular, and tissue fluid excess were 1.3 L (Q1-Q3: 0.5, 2.3), 0.1 L (Q1-Q3: -0.1, 0.4), and 1.9 L (Q1-Q3: 1.1, 2.8), respectively. Total and tissue fluid excess had the strongest correlation with the CCS (Total fluid excess rho = 0.31; P < .001, tissue fluid excess rho = 0.33; P < .001). In adjusted analyses, patients in the highest quartile had significantly higher risk of the composite outcome compared with Q1: total fluid excess hazard ratio (HR) 2.11 [95% confidence interval (CI) 1.21-4.05, P = .010], intravascular fluid excess HR 2.16 (1.19-3.90, P = .011), and tissue fluid excess HR 2.81 (1.49-5.32, P = .001).

Compartment-specific estimates of fluid overload obtained with the BioScan Touch i8 IVF were independently associated with adverse outcomes in ambulatory patients with chronic HF, beyond NT-proBNP and clinical surrogates of congestion. These findings support the potential role of BIA-derived indexes, particularly tissue fluid excess, as complementary tools for risk stratification in this population.