European Journal of Echocardiography | 2021
The influence of hemodialysis-induced preload changes on the propagation speed of natural shear waves
Abstract
\n \n \n Type of funding sources: Public grant(s) ā National budget only. Main funding source(s): Research Foundation - Flanders (FWO)\n \n \n \n Shear wave elastography (SWE) is a novel ultrasound technique based on the detection of transverse waves travelling through the myocardium using high frame rate echocardiography. The propagation speed of these shear waves is dependent on the stiffness of the myocardium. Previous studies have shown the potential of SWE for the non-invasive assessment of myocardial stiffness. It is unclear, however, if preload changes lead to measurable changes in the shear wave propagation speed in the left ventricle. In patients undergoing hemodialysis, the volume status is acutely changed. In this way, the effect of preload changes on shear wave speed can be assessed.\n \n \n \n The aim of this study was to explore the influence of preload changes on end-diastolic shear wave propagation speed.\n \n \n \n Until now, 6 patients (age: 80[53-85] years; female: n\u2009=\u20092) receiving hemodialysis treatment were included. Echocardiographic images were taken before and every hour during a 4 hour hemodialysis session. Left ventricular parasternal long-axis views were acquired with an experimental high frame rate ultrasound scanner (average frame rate: 1016[941-1310] Hz). Standard echocardiography was performed with a conventional ultrasound machine. Shear waves were visualized on tissue acceleration maps by drawing an M-mode line along the interventricular septum. Shear wave propagation speed after mitral valve closure (MVC) was calculated by measuring the slope of the wave pattern on the acceleration maps (Figure A).\n \n \n \n Over the course of hemodialysis, the systolic (141[135-156] mmHg vs. 165[105-176] mmHg; p\u2009=\u20090.35 among groups) and diastolic blood pressure (70[66-75] mmHg vs. 82[63-84] mmHg; p\u2009=\u20090.21 among groups), heart rate (56[54-73] bmp vs. 57[50-67] bpm; p\u2009=\u20090.76 among groups), E/A ratio (1.6[0.7-1.8] vs. 1.2[0.6-1.4]; p\u2009=\u20090.43 among groups) and E/eā (14[9-15] vs. 9[8-13]; p\u2009=\u20090.24 among groups ) remained the same. The ultra-filtrated volumes are shown in Figure B. The shear wave propagation speed after MVC gradually decreased during hemodialysis (6.7[5.4-9.7] m/s vs. 4.4[3.6-9.0] m/s; p\u2009=\u20090.04 among groups) (Figure C). There was a moderate negative correlation between shear wave speed and the ultra-filtrated volume (r=-0.63; p\u2009<\u20090.01) (Figure D).\n \n \n \n The shear wave propagation speed at MVC significantly decreased over the course of hemodialysis and correlated to the ultra-filtrated volume. These results indicate that alterations in left ventricular preload affect the speed of shear waves at end-diastole. End-diastolic shear wave speed might therefore be a potential novel parameter for the evaluation of the left ventricular filling state. More patients will be included in the future to further explore these findings.\n Abstract Figure.\n