Background: Re-hospitalization of patients with congestive heart failure (CHF) for pulmonary congestion or edema (PCE) is an unresolved problem. The main barrier to a solution of this problem is the lack of a reliable method to recognize the early asymptomatic or slightly symptomatic stage of evolving PCE. Lung impedance (LI) decreases as fluid accumulates in the lungs eventually resulting in PCE. Monitoring of PCE in this study was performed by a device based on an algorithm which enabled to calculate the net LI with a 25-fold higher sensitivity than current devices using the traditional technique.
Aim: To evaluate the effectiveness of treatment of CHF patients guided by the new LI device.
Methods: As first step we proposed a model to calculate normal baseline lung impedance (BLI) in CHF patients already having some degree PCE. Based on BLI we proposed DLIR= (LI/BLI-1)´100%, reflecting the degree of PCE, as the parameter monitored on each visit. No hospitalization for PCE occurred at DLIR> -24%. Therefore, DLIR= -20% was used as the threshold for therapy intensification in the device-guided group.
Results: 222 CHF patients (age 67±10 years, 85% male, LVEF 28±3%, initial NT-proBNP level- 3,771±5185 pg/ml) at NYHA II/III/IV (120/54/48) were recruited and followed in the outpatient clinic for a mean of 32 months (6,080 visits). Patients were randomized (1:1) into 2 well-matched groups according to treatment policy. Group 1 patients were treated according to clinical assessment and measured DLIR while group 2 patients were treated by clinical assessment only. In group 1 there were 1.7-fold less cardiovascular (CV) and 1.6-fold less hospitalizations for non-cardiovascular causes per year follow up (p<0.01). There were 14 and 28 cardiovascular deaths in groups 1 and 2, respectively (p=0.012), and 10 and 9 non-cardiovascular deaths in groups 1 and 2, respectively (p=NS).
Conclusion: Preemptive DLIR-guided decongestive treatment reduced recurrent CV hospitalizations and improved survival in CHF patients.
