Vector mapping of deformation and blood flows in patients with ascending aortic aneurysm

Abstract

The authors performed clinical studies based on modelling of an ascending aortic aneurysm in 37 patients and 10 apparently healthy subjects. Echocardiography was carried out in the B-mode using the Vivid E9 device (USA, GE). The linear dimensions of the aorta were assessed at three points - in the immediate vicinity of the valves, in the area of the maximum dilatation and in the area of decreased dilatation with registration of blood flow velocity in the aorta. The aortic walls were contoured with the division of equal intervals into 4 portions in order to obtain longitudinal shear deformation velocity during the cardiac cycle. We worked out a system of assessing the velocity vector fields with the help of transthoracic echocardiography in patients with an ascending aortic aneurysm, based on registration of blood flows, which made it possible to obtain the components of velocity. We also determined an optimal method of assessing turbulence in the aorta taking into account the direction of the vectors. Obtained were the numerical data of aortic wall deformation velocity in the longitudinal direction and calculation of the weighting function with the distinction between pathology and the norm. Based on the deformation, the distance between the registered points, and the movement of the vascular wall, we determined the reference values of blood flow velocity inside the aorta and immediately close to its walls.