Feasibility and prognostic value of a wearable thoracic impedance sensor in acutely decompensated heart failure with volume overload (Preprint)
BACKGROUND Incomplete relief of congestion in acute decompensated heart failure (HF) relates to poor outcome. However, congestion can be difficult to evaluate, stressing the urgent need for new objective approaches. Continuous bioimpedance monitoring might be an effective way for serial fluid status assessment due to the inverse correlation with tissue hydration. OBJECTIVE Study the feasibility of a wearable bioimpedance sensor to assess longitudinal changes in fluid status and their relation
... nd their relation with HF hospitalization and all-cause mortality. METHODS A wearable bioimpedance monitoring device was used for thoracic impedance measurements. Thirty-six patients with signs of acute decompensated HF and volume overload were included. Changes in the resistance at 80 kHz (R80kHz) were used for analyses and patients' fluid balance (fluid in/out) was taken as a reference. Patients were divided in two groups, i.e. those with an increase or decrease in R80kHz during hospitalization. RESULTS Respectively 24 versus 12 patients showed an increase or decrease in R80kHz during hospitalization. For the total study population, a moderate negative correlation was found between changes in fluid balance (in/out) and relative changes in R80kHz during hospitalization (r=-0.51, P<.001). Clinical outcome at both 30 days and one year of follow-up was better for patients showing an increase in R80kHz (at one year 88% versus 50%, P=.005 for all-cause mortality and 75% versus 25%, P=.001 for the composite of all-cause mortality and HF hospitalization). A decrease in R80kHz resulted in a significant hazard ratio of 4.96 (95% CI 1.82-14.37, P=.003) on the combined endpoint. CONCLUSIONS The novel wearable bioimpedance device was able to track longitudinal changes in fluid status. Patients who do not show an improvement in thoracic impedance tend to show a worse clinical outcome, indicating its potential use as a prognostic parameter for clinical outcome.