Comparison of Nt-proBNP Concentrations When in or out of Heartlogic Alerts

Abstract

Background N-terminal pro-B-type natriuretic peptide (NT-proBNP), a non-active fragment of the prohormone proBNP, is produced by the heart and released in response to volume or pressure overload. NT-proBNP has proven to be a valuable biomarker in the diagnosis and prognosis of heart failure (HF), and NT-proBNP concentrations rise with worsening HF. HeartLogic, a multi-sensor composite index and alert algorithm, aggregates multiple physiologic trends associated with HF status, and proactively provides alerts for worsening HF with high sensitivity and low alert burden. Objective To compare NT-proBNP concentrations during periods IN or OUT of an active HeartLogic alert. Methods The MultiSENSE study enrolled 900 HF patients with an implanted COGNIS CRT-D, and followed them up to 1 year. Device software was modified to permit collection of chronic trends HeartLogic leveraged (heart sounds, heart rate, thoracic impedance, respiration and activity). Clinicians were blinded to individual sensors and results of HeartLogic during the study. Optional NT-proBNP tests were conducted when clinically needed (e.g., patients hospitalized with HF symptoms). HeartLogic index of the day before each of the NT-proBNP test dates was extracted. Based on HeartLogic alert state (i.e., IN alert vs OUT of alert), NT-proBNP concentrations were divided into two groups and compared using a one-way ANOVA. Results Of a total of 855 valid NT-proBNP tests in 741 patients with valid associated HeartLogic index, 180 NT-proBNP concentrations were measured in 150 patients while the HeartLogic alert state was IN alert, and 675 were measured in 616 patients while HeartLogic was OUT of alert. Figure 1 shows when HeartLogic was IN alert, the NT-proBNP concentrations (6957.9±10398.0 pg/ml) were significantly higher than those when HeartLogic was OUT of alert (1675.5±4403.1 pg/ml) (p Conclusion HF patients’ NT-proBNP concentrations were significantly elevated when HeartLogic was IN alert status, consistent with the HeartLogic algorithm capturing clinical worsening of HF status.