Noninvasive Lung Impedance Monitoring Cuts Heart Failure Hospitalizations by 74% in HFpEF Patients
Key Insights
A randomized trial found lung-impedance guided care using the CardioSet Edema Guard Monitor (search) reduced heart failure hospitalizations by 74% in HFpEF patients over a median follow-up of 38.4 months.
Patients in the guided-care arm also experienced a 74% lower rate of heart failure death and a 60% lower rate of all-cause mortality compared to standard care.
Clinicians using the device adjusted medications more than twice as frequently and detected lung congestion significantly earlier, enabling intervention at the preclinical stage.
Treatment guided by a noninvasive device that monitors fluid accumulation in the lungs substantially reduced hospitalizations and deaths among patients with heart failure with preserved ejection fraction (HFpEF) (search), according to research presented at the American College of Cardiology's Annual Scientific Session (ACC.26).
Patients whose management involved the CardioSet Edema Guard Monitor (search) were 74% less likely to be hospitalized for heart failure and 74% less likely to die from heart failure during more than three years of follow-up. Researchers attribute the benefits to an enhanced ability to detect fluid buildup early and fine-tune medications in response to the level of lung congestion.
"This device offers a way to change the treatment of patients with heart failure in order to start treatment early — before the patient starts to experience symptoms. The secret of success is to enable us to intervene at the preclinical stage when the reaction to treatment is more powerful," said Michael Kleiner-Shochat, MD, professor and head of the heart failure clinic at Hillel Yaffe Institute of Cardiology in Hadera, Israel, and the study's first author.
How the Device Works
The CardioSet device measures resistance to electrical current, or impedance, across the lungs. As fluid accumulates, the lungs become less resistant to electrical current, causing impedance to decrease. Previous noninvasive techniques have been limited in accuracy because measurements include a large noise signal from the surrounding chest wall.
The CardioSet device overcomes this limitation by using a configuration of more electrodes, which enables the larger noise signal from the chest wall to be calculated and eliminated. This provides an accurate assessment of lung impedance even when changes in fluid accumulation are small.
"It's a simple, scalable device that could be used at each point of care — in clinics and, in the future, in the patient's home — and you can get indications about the patient's lung fluid status very quickly," said Kleiner-Shochat, who is also the founder of CardioSet Medical (search), maker of the device, and a member of its Board of Directors.
Trial Design and Results
Researchers enrolled 150 patients with HFpEF and randomized half to receive lung-impedance guided care at each monthly outpatient clinical visit, while the other half received standard care. Baseline characteristics were similar between groups, and the number of outpatient clinic visits was equal. The CardioSet device was used to measure pulmonary congestion during each outpatient visit for all patients, but treating physicians were aware of the results only in the lung-impedance guided group.
Patients were followed for a median of 38.4 months. The study's primary endpoint was recurrent heart failure hospitalization. Researchers tracked 19 events in the lung-impedance guided group compared with 93 events in the standard care group — a 74% reduction favoring the guided-care arm. The time to first heart failure hospitalization was also significantly longer in the guided group, averaging 602 days versus 83 days among those receiving standard care.
Mortality outcomes were similarly improved. Compared with standard care, patients receiving lung-impedance guided care showed a 60% lower rate of all-cause death and a 74% lower rate of death from heart failure during the three-year follow-up. There were no device-related adverse events.
Clinicians adjusted medications more than twice as frequently in the guided-care group, and adjustments were made significantly earlier in the development of lung congestion.
Comparison with HFrEF and Limitations
Researchers noted that the benefits shown in this trial exceed those reported in a previous trial involving patients with heart failure with reduced ejection fraction (HFrEF) (search). They suggested that lessons learned from the prior trial may have helped clinicians feel comfortable using diuretics more aggressively in response to impedance monitoring signals. Additionally, the same dose of diuretics may have a stronger effect in HFpEF patients than in HFrEF patients due to physiological differences between the two types of heart failure.
The trial was limited to a single center. Kleiner-Shochat noted that a multicenter study conducted across different countries could help confirm the feasibility and effectiveness of lung-impedance guided heart failure treatment in a broader range of settings. The study was conducted at the Hillel Yaffe Medical Center without external funding.