Non-Invasive Lung IMPEDANCE-Guided Preemptive Treatment in Chronic Heart Failure Patients: A Randomized Controlled Trial (IMPEDANCE-HF Trial)

Background: Previous investigations have suggested that lung impedance (LI)-guided treatment reduces hospitalizations for acute heart failure (AHF). A single-blind 2-center trial was performed to evaluate this hypothesis (ClinicalTrials.gov-NCT01315223). Methods: The study population included 256 patients from 2 medical centers with chronic heart failure and left ventricular ejection fraction <= 35% in New York Heart Association class II-IV, who were admitted for AHF within 12 months before recruitment. Patients were randomized to a control group treated by clinical assessment and a monitored group whose therapy was also assisted by LI, and followed for at least 12 months. Noninvasive LI measurements were performed with a new high-sensitivity device. Patients, blinded to their assignment group, were scheduled for monthly visits in the outpatient clinics. The primary efficacy endpoint was AHF hospitalizations; the secondary endpoints were all-cause hospitalizations and mortality. Results: There were 67 vs 158 AHF hospitalizations during the first year (P < .001) and 211 vs 386 AHF hospitalizations (P < .001) during the entire follow-up among the monitored patients (48 32 months) and control patients (39 26 months, P = .01), respectively. During the follow-up, there were 42 and 59 deaths (hazard ratio 0.52, 95% confidence interval 0.35-0.78, P = .002) with 13 and 31 of them resulting from heart failure (hazard ratio 0.30, 95% confidence interval 0.15-0.58 P < .001) in the monitored and control groups, respectively. The incidence of noncardiovascular death was similar. Conclusion: Our results seem to validate the concept that LI-guided preemptive treatment of chronic heart failure patients reduces hospitalizations for AHF as well as the incidence of heart failure, cardiovascular, and all-cause mortality.