Assessment Of Left Intra-ventricular Energy Loss In Uremia Patients After Single Hemodialysis Using Ultrasonic Vector Flow Mapping

Objective: Vector flow mapping(VFM)was used to evaluate the overall level energy loss of left ventricular diastolic phase,isovolumetric contraction(IVC)and rapid ejection(RF)in patients with uremia in long-term maintenance hemodialysis.The effects of single hemodialysis on the average EL of left ventricular diastolic phase,IVC and RF in uremic patients were evaluated and the linear relationship between the average EL of the left ventricle and the corresponding normal diastolic and systolic function parameters was preliminarily investigated.Methods: Forty-nine patients with long-term maintenance hemodialysis were enrolled as case group and 32 healthy adults as normal control group.Echocardiography was performed 1hour before dialysis and 1 hour after dialysis in patients with uremia.Conventional two-dimensional dynamic grayscale images and spectral Doppler images were collected.VFM mode was employed,in the standard apical three-chamber section for simultaneous acquisition of three complete dynamic cardiac cycles of dynamic color Doppler images.The conventional cardiac diameters were measured on-line.Also left ventricular diastolic and systolic function parameters were measured on-line.The apical three-chamber view with dynamic color Doppler images were introduced into a dedicated post-processing workstation to measure the EL parameters at the isovolumetric diastolic(P1),early diastolic(P2),rapid filling(P3),mid-diastolic(P4),atrial systolic(P5),isovolumetric contraction phase(P6)and rapid ejection period(P7).The differences between the uremic patients before and after HD were compared to the normal control group.The differences were compared between the uremic patients before and after HD.The average left ventricle EL and the conventional parameters at the same phases of left ventricular diastole and systole was analyzed for the linear correlation.Results: 1.Comparison of the conventional parameters of left ventricular diastolic and systolic function : before and after HD in uremic patients compared with the control group,A and E/e of before-HD were higher than those in the control group,E/A and e of before-HD were lower than the control group(P<0.05).After-HD,A and E/e were higher than those in the control group,E/A and e were lower than those in the control group(P<0.05).Comparison of uremic patients before and after HD,tei index after-HD were higher than those before-HD(P<0.05),E,A,e,e/a was lower(P < 0.05).2.Comparison of the average left ventricle EL during P1~P7 phase: before and after HD in uremic patients compared with the control group,the average EL of the left ventricle in the P1,P3,P4,P5,P6 and P7 phases before-HD was higher than that in the control group(P<0.05),and average EL in the P2 phase was higher than that of the control group(P>0.05).The average EL in the P1,P5 and P7 after-HD was higher than that in the control group(P<0.05).Compared with the patients before-HD,the average EL of the left ventricle during P1~P6phase after-HD were lower(P<0.05).The average EL of the left ventricular P7 phase was not significantly different from that before-HD(P > 0.05).3.Correlation between the average EL and conventional echocardiographic functional parameters of left ventricle during P3,P5 and P7 phase: there was a positive correlation between EL-P3 and E in the control group,before-HD and after-HD(r=0.428,P<0.05)(r=0.398,P<0.01)(r=0.414,P<0.01).There was a positive correlation between EL-P5 and A in the control group,before-HD and after-HD(r=0.463,P<0.01)(r=0.455,P<0.01)(r=0.715,P<0.01).There was a negative correlation between EL-P5 and e/a in the control group,before-HD and after-HD(r=-0.409,P<0.05)(r=-0.448,P<0.01)(r=-0.409,P<0.01).There was a negative correlation between EL-P5 and E/A in before-HD and after-HD(r=-0.376,P<0.05)(r=-0.317,P<0.05).Conclusion:(1)The average EL of left ventricular overall in P1~P7 period of uremic hemodialysis patients was almost all higher than that of the control group,suggesting that the left ventricle diastolic and systolic function of uremic hemodialysis patients decreased.(2)The average EL of left ventricular overall in P1 ~ P6 after-HD was lower than that before-HD,and the change of EL-P7 was not obvious.It suggested that single hemodialysis could improve the diastolic function of the heart,but it still could not effectively improve the systolic function of the heart in the rapid ejection period.(3)There is a good linear correlation between EL-P3 and E,EL-P5 and A,EL-P5 and e/a,suggesting that EL can also quantitatively reflect left ventricular diastolic function in uremic patients.