LAUSR

BACKGROUND Outpatient monitoring and management of patients with heart failure (HF) reduces hospitalizations and healthcare costs. However, the availability of non-invasive approaches to assess congestion are limited. Non-Invasive Venous waveform Analysis (NIVA) uses a unique physiologic signal, the morphology of the venous waveform, to assess intracardiac filling pressures. This study is a proof of concept analysis of the correlation between NIVA value and PCWP and the ability of NIVA value to predict PCWP >18 mmHg in subjects undergoing elective right heart catheterization (RHC). PCWP was also compared across common clinical correlates of congestion. METHODS A prototype NIVA device which consists of a piezoelectric sensor placed over the skin on the volar aspect of the wrist, connected to a data capture control box, was used to collect venous waveforms in 96 patients during RHC. PCWP was collected at end-expiration by an experienced cardiologist. The venous waveform signal was transformed to the frequency domain (Fourier transform) where a ratiometric algorithm of the frequencies of the heart rate and its harmonics was used to derive a NIVA value. RESULTS NIVA values were successfully captured in 83 of 96 enrolled patients. PCWP ranged from 4 - 40 mmHg with a median of 13 mmHg. NIVA values demonstrated a linear correlation with PCWP (r=0.69, p<0.05). CONCLUSIONS This observational proof of concept study utilizing a prototype NIVA device demonstrates a moderate correlation between NIVA value and PCWP in patients undergoing RHC. NIVA thus represents a promising developing technology for non-invasive assessment of congestion in spontaneously breathing patients.