Continuous, real-time, noninvasive hemodynamic cardiac Doppler monitoring with a novel hands-free device: A feasibility study compared to standard echo

This study sought to determine the feasibility of using noninvasive cardiac hemodynamics (NICHE), a new noninvasive Doppler-based device, to monitor real-time, simultaneous tissue and blood-flow Doppler measurements in a clinical setting, and to obtain preliminary performance data compared to a commercially available system. Doppler-based measurements have been shown to correlate well with invasive hemodynamic data and diastolic function, but their use in clinical applications has been limited by various technical issues. The NICHE device was developed to obtain simultaneous tissue and bloodflow Doppler measurements automatically, in real-time and in a hands-free manner. Thirty participants (ten normal volunteers and 20 patients in a cardiac rehab program) underwent standard echocardiographic/Doppler studies followed immediately by NICHE monitoring. Early diastolic transmitral blood-flow velocity (E) and tissue Doppler myocardial wall velocity during early relaxation (E0) were acquired using a standard echo device; and E/E0 was derived post hoc. NICHE measurements included E, E0, and directly measured instantaneous E/E0. NICHE was successfully used in 28 participants. Measurements of E_NICHE ranged from 40 cm/s to over 120 cm/s and correlated well with E_echo (R=0.93). E'_NICHE ranged from 2 to 23 cm/s and correlated well with the averaged E'_echo (R=0.91). Directly measured E/E'_NICHE ratios ranged from 3 to 23 and correlated well with derived E/E'_echo (R=0.91). The NICHE device can monitor patients in a hands-free manner and can supply real-time Doppler derived measurements of hemodynamic parameters and diastolic function that correlate well with measurements from standard echo devices.