LAUSR

Introduction: The ventricles accelerate and decelerate blood; the resulting disturbances propagate through the arterial system as waves. These waves contain clinically useful information: e.g. their magnitude and timing varies with cardiac performance and their speed depends on arterial stiffness. These properties can be studied using Wave Intensity Analysis (WIA) [1] and have been shown to be altered in heart failure [2]. Conventional WIA relies on invasive catheter measurements of blood pressure and velocity. We have developed and validated a new non-invasive ultrasound-based method that allows accurate WIA. Methods: Employing a novel WIA formulation [3] based on diameter and velocity, and a ultrafast ultrasound imaging system (Verasonics, Kirkland, USA), wave intensity was measured in the abdominal aorta of rabbits. B-mode images were acquired at 1000 Hz, and diameter and velocity measured using standard cross-correlation techniques (the latter after spatio-temporal filtering to enhance the blood signal). Comparative measurements were made with a conventional WIA catheter-based system (Phillips Volcano, San Diego, USA). Ventricular dysfunction was induced by administering esmolol. Results: Measured non-invasive peak wave intensities showed good agreement with catheter-based ones (r = 0.73, p = 0.04, n = 8). Changes in the intensity and timing of the forward compression wave could be detected 1 minute after esmolol administration (n = 10): peak intensity reduced by 30.3% (p = 0.003) and was delayed 9.30 ms (p = <0.001). Conclusion: This new method enables wave intensities, reflections and speeds to be obtained non-invasively at any ultrasound accessible site. It could provide a clinically useful way to detect heart failure, and alteration of arterial tone and stiffness. REFERENCES [1] Parker KH. Med Biol Eng Comput 2009;47:175–88. [2] Curtis SL. Am J Physiol Heart Circ Physiol 2007;293:H557–H62. [3] Feng J, Khir AW. J Biomech 2010;43:455–62. © 2019 Association for Research into Arterial Structure and Physiology. Publishing services by Atlantis Press International B.V. This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/). *Corresponding author. Email: [email protected]