Intrathoracic impedance monitoring to detect chronic heart failure deterioration: Relationship to changes in NT‐proBNP

Abstract

Background: An alert algorithm, based on intrathoracic impedance monitoring, has been incorporated into a cardiac resynchronisation device (CRT) to detect pulmonary fluid accumulation, and to audibly alert patients to decompensating chronic heart failure (CHF). Aims: To evaluate this algorithm, alert events were correlated with changes in NT-proBNP concentration and CHF status. Methods and results: In a prospective observational study of 62 patients (89% male, aged 67 ± 1 year), NT-proBNP plasma concentrations, clinical CHF status, and device data were collected at enrolment, during regular follow-up and at device alerts. Over a mean follow-up of 27 ± 2 weeks, pooled data indicated a weak, but significant inverse relationship between relative changes in intrathoracic impedance and NT-proBNP (r = −0.3; p b 0.001). In 52 device alerts from 35 patients, NT-proBNP increased by 66 ± 19% from 2039 ± 331 pg/ml (p b 0.001). The increase in NT-proBNP was higher in alerts with clinical signs of CHF deterioration (n = 30, 89 ± 25%; p b 0.001) than in alert events without clinical signs (n = 22, 25 ± 15%; p =n.s.). Conclusion: Intrathoracic impedance based alert events are associated with a significant increase in NT-proBNP concentration. These data indicate that intrathoracic impedance monitoring might facilitate the outpatient management of CHF patients with implanted CRT devices.

Decreased Intrathoracic Impedance Associated With OptiVol Alert Can Diagnose Increased B-Type Natriuretic Peptide – MOMOTARO (Monitoring and Management of OptiVol Alert to Reduce Heart Failure Hospitalization) Study –

“…Lüthje et al reported that natriuretic peptide-proBNP is increased at the time of OptiVol alerts as compared with times without HF symptoms and that a change in ITI is negatively correlated with a change in N-terminal-proBNP. 25 Similarly, in this study, ITI ratio ≤0.96 at the time of OptiVol alert was associated with an increase in TRPG, dimension of the inferior vena cava, and E/A ratio and was also correlated with a reduction in the number of red blood cells, hemoglobin, total protein, and albumin, all of which relate to fluid retention. ICD and Data given as mean ± SD.…”

Combined Heart Failure Device Diagnostics Identify Patients at Higher Risk of Subsequent Heart Failure Hospitalizations

“…Previous studies focused on intrathoracic impedance monitoring to predict future events without looking at other diagnostic parameters or they have looked at single HF device diagnostic parameters without combining them into an algorithm. The relationship between intrathoracic impedance and changes in fluid status has been proven by some studies that showed a significant correlation between impedance measurements and N-terminal pro-B-type natriuretic peptide concentration and pulmonary capillary wedge pressure (17). Relating changes in impedance to HF symptoms and clinical events has been more difficult.…”

Intrathoracic Impedance Monitoring, Audible Patient Alerts, and Outcome in Patients With Heart Failure

“…25 One observational, nonrandomized study showed that the number of heart failure hospitalizations was reduced in patients in whom the audible fluid alert was activated. 19 In the present study, OptiVol alerts were present in two thirds of patients who were evaluated during an (unplanned) outpatient visit.…”