Study On Left Ventricular Hemodynamics Characteristics With Aortic Regurgitation By Vector Flow Mapping

Objective: The purpose of this study was to qualitatively and quantitatively analyze the changes of hydrodynamic parameters in the left ventricular with different degrees of aortic regurgitation(AR)during diastole period by using vector flow mapping(VFM)and to further explore the relationship between the parameters and cardiac structure,to evaluate its application valve in the evaluation of the degree of aortic regurgitation.Methods: Forty-two AR patients with LVEF > 50% and fourteen healthy volunteers were recruited.According to the 2017 recommendations of the American Echocardiography Association for non-invasive evaluation of valvular regurgitation,the patients were divided into mild,moderate and severe valvular regurgitation groups(AR1,AR2,AR3 group).The routine echocardiographic parameters were collected by Aloka Prosound F75.After switching VFM mode,the standard three-chamber color flow dynamic images were stored and then imported into the DAS-RS1 workstation.According to Time-Flow curve,valve opening and closing and ECG,the cardiac cycle can be divided into 5 phases: isovolumic relaxation(P1),rapid filling(P2),slow filling(P3),atrial contraction(P4),total diastole(P5).The Vortex area(Av),Vortex circulation(Cv),average energy loss of the total(a EL-T)and three segments left ventricle(a EL-B、a EL-M、a EL-A),the shear stress of the whole anterior septum and three segments were measured by DAS-RS1.Results:1.VFM qualitative observationonly one small vortex was occasionally seen during the P1 phase in the AR1 group,and the other phases were similar to the control group.while AR2 and AR3 groups lost their original state of vortex and its abnormal degree including the number,area and position of the vortex were positively correlated with the degree of regurgitation.2.VFM quantitative parameters comparisonCompared with control,AR patients had higher a EL-T,a EL-B,a EL-M,a EL-A during different periods and had a trend of a EL-B> a EL-M>a EL-A.With the aggravation of aortic regurgitation,P2-a EL-T and P2-a EL-M increase gradually,and there was statistical difference(P<0.05).Compared with control,AR patients had higher Av and Cv.With the aggravation of aortic regurgitation Av and Cv increase gradually.Compared with control,the basal segment WSS during P3 and P5 periods were higher in the AR2 and AR3 groups,and there was statistical difference(P<0.05).There were a trend of the WSS from basal segment to apical segment decreased in turn.3.Correlation analysisThere was a significant correlation between the parameters of quantitative evaluation of the degree of valvular regurgitation and a EL-T.The more severe the degree of valvular regurgitation,the larger the diameter and volume of left ventricular,and its were correlated with a EL-T significantly.Multivariate linear regression showed that LVEDD could be an independent impact of a EL-T.Conclusion: VFM technique can qualitatively and quantitatively analyze hemodynamic characteristics within left ventricular in AR patients and provide a new parameter for the classification of this disease.