Study of left ventricular systolic function by vector flow mapping in patients with aortic stenosis retained in ejection fraction

Objective To quantitatively analyze the changes in left ventricular mean energy loss (EL) using blood flow vector imaging (VFM) in patients with aortic stenosis retained by ejection fraction. Methods Thirty-five subjects were selected as the control group, and 71 patients with aortic stenosis were chosen as the case group, including mild aortic stenosis (miAS) group(23 cases), moderate aortic stenosis (moAS) group(23 cases), and severe arterial stenosis (seAS) group(25 cases). Left atrial anteroposterior diameter (LAA), left ventricular end-diastolic diameter (LVEDD), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF) and E/A were measured by conventional echocardiography. The average total EL (EL-T), average basal segment EL (EL-B), average middle segment EL (EL-M) and average apical segment EL (EL-A) of each isovolumic contraction phase (IVC) and rapid ejection phase (RE) were measured by VFM, and the differences in mean EL among each groups were compared. Results Compared with those in the control group, average EL-B, average EL-M and average EL-T in each case group of the left ventricle during IVC and RE were increased, the average EL-A in seAS group of the left ventricle during IVC were increased, and the differences were statistically significant(all P<0.05). Compared with those in miAS group, the average EL-B, average EL-M and average EL-T in seAS group of the left ventricle during IVC and RE were increased, and the differences were statistically significant(all P<0.05). Compared with those in miAS group, the average EL-A in moAS group and seAS group of the left ventricle during RE were increased, and the differences were statistically significant(all P<0.05). Conclusions VFM technology can directly reflect the hemodynamic changes in the left ventricular chamber of patients with aortic stenosis retained by ejection fraction, and provide a new method for the evaluation of left ventricular systolic function in patients with aortic stenosis. Key words: Echocardiography; Aortic stenosis; Ejection fraction retention; Vector flow mapping; Energy loss; Ventricular function, left