Estimating Left Ventricular Contractility Through Carotid Artery Distension: A Portable Device Utilizing A-Mode Ultrasound and Surrogate Marker Analysis

Non-invasive assessment of left ventricular (LV) function is crucial for early diagnosis and management of cardiovascular diseases. The Acceleration Time (AT) to Ejection Time (ET) ratio, is a measurement used to assess the contractility of the left ventricle (LV) of the heart. This study explores the feasibility of a novel device for a surrogate estimation of the AT/ET ratio using carotid artery distension dynamics. In this in-vivo study, 17 healthy young male participants were recruited. A custom-designed device combining A-mode ultrasound and a pocket Doppler was used to acquire simultaneous measurements of carotid artery distension and blood flow velocity. The pocket Doppler aided in identifying critical events in the carotid artery flow waveform, serving as reference points for analyzing the second derivative of the carotid distension waveform obtained by the A-mode component. This facilitated the estimation of surrogate AT, ET, and the AT/ET ratio from carotid artery dynamics. The study demonstrated a strong correlation between surrogate markers and reference measurements. The surrogate AT measured from carotid distension showed a significant correlation (r = 0.81, p < 0.05) with the reference AT obtained from LVOT flow. Similarly, the surrogate ET derived from carotid distension exhibited a strong correlation (r = 0.83, p < 0.05) with the reference ET from LVOT. Importantly, the surrogate AT/ET ratio estimated from carotid artery dynamics displayed a significant correlation (r = 0.8, p < 0.05) with the reference AT/ET ratio measured using the gold-standard LVOT flow waveform. This study suggests that the combined A-mode ultrasound and pocket Doppler device has the potential to serve as a non-invasive tool for estimating key LV function parameters, including the clinically relevant AT/ET ratio, through analysis of carotid artery distension. Further research with a larger and more diverse population is warranted to validate this approach for broader clinical applications.