A noninvasive device used to monitor early fluid accumulation in the lungs of patients with heart failure with preserved ejection fraction (HFpEF) substantially reduced HF hospitalizations and mortality, according to results from the IMPEDANCE-HFPEF trial presented during ACC.26.

HF hospitalizations are driven by pulmonary congestion that precedes HF symptoms and hospitalizations by days or weeks. Noninvasive tools currently used do not allow direct measurement of lung fluid. The device tested in the trial isolates the lung signal by removing chest wall noise, which enables direct and sensitive measurement of lung fluid changes by measuring resistance to electrical current, or impedance. This detection of lung fluid allowed trial clinicians to adjust treatment medications more frequently and earlier in the management of pulmonary congestion, according to researchers.

Conducted at a single center in Israel, the single-blind trial enrolled 150 patients with HFpEF. They were about 75 years old and 62% women, with an LVEF about 60%. Half of the patients were randomized to receive lung-impedance guided care and half received standard care. Baseline characteristics were similar between groups and the number of outpatient clinic visits was equal. The CardioSet Edema Guard Monitor was used to measure pulmonary congestion during each outpatient visit for all patients, but treating clinicians were aware of the results of lung impedance measurements only in the lung-impedance guided group. Physicians made treatment adjustments according to study protocols.

For the primary endpoint of recurrent HF hospitalization at the median 38.4 months follow-up, there was a 81% reduction in favor of the lung-impedance guided group. The time to first HF hospitalization was 602 days on average for the lung-impedance guided group and 83 days for the standard-care group.

Additionally, patients in the lung-impedance group had a 65% lower rate of all-cause death and an 81% lower rate of HF death than the standard-care group. There were no device-related adverse events.

Of note, clinicians adjusted medications more than twice as frequently, and adjustments were made significantly earlier in the development of lung congestion, in the lung-impedance group.

“This device offers a way to change the treatment of patients with [HF] in order to start treatment early – before the patient starts to experience symptoms,” said Michael Kleiner-Shochat, MD, PhD, FACC, the trial’s lead author. “The secret of success is to enable us to intervene at the preclinical stage when the reaction to treatment is more powerful.”

Keywords: ACC Annual Scientific Session, ACC26, New Orleans, Heart Failure, Preserved Ejection Fraction, Hospitalization, Mortality, Lung