Feasibility Analysis Of Effective Left Ventricular Stroke Volume Evaluated By Combined Use Of Multiple Echocardiographic Techniques In Patients With Mitral Regurgitation

Objective:To explore the reliability of effective left ventricular stroke volume evaluated by combined use of two-dimensional,three-dimensional and Doppler echocardiographic techniques in patients with mitral regurgitation(MR).Methods:50 patients with MR diagnosed in our hospital from October 2018 to December 2019 were collected as the MR group(case group).The MR group was further divided into two subgroups: Group MR1(mild lesion group,25 cases with below moderate MR),and Group MR2(severe lesion group,25 cases with moderate or above MR)according to the degree of MR.25 normal people undergoing checkup in our hospital during the same period were selected as Group C(control group)according to the principle of gender and age matching.Two-dimensional and three-dimensional tracing method were used to measure left ventricular end-diastolic volume(LVEDV)and left ventricular end-systolic volume(LVESV),and the difference of the two was the stroke volume(SV),i.e.SV by 2D tracing method,and SV by 3D tracing method.The area of left ventricular outflow was calculated by measuring inner diameter tract using conventional two-dimensional echocardiography.Another area of left ventricular outflow tract was directly sketched by the three-dimensional full volume method.The velocity-time integral(VTI)was measured by pulse Doppler.SV is calculated based on the left ventricular outflow tract area and VTI,i.e.SV by 2D Doppler method,and SV by 3D Doppler method.Conventional 2D ultrasound was used to measure the internal diameters of the right and left palmar arteries and the two lateral first dorsal iliac arteries,the areas can then be calculated,and the VTI was obtained by using pulse Doppler.The blood flow of a single cardiac cycle was calculated based on the peripheral arterial area and VTI,and finally the average of the above four points was taken.The SV measured by two-dimensional tracing,three-dimensional tracing,two-dimensional Doppler,and three-dimensional Doppler and peripheral arterial blood flow were compared and analyzed between groups.Result:General data comparison: There were no significant differences in age,sex,body surface index,heart rate,smoking and drinking among the groups(all P >0.05).Comparison and correlation of SV measured by four methods and peripheral arterial blood flow in group C: Comparison of SV measured in 2D and 3D: There were no statistical differences between SV measured by 2D tracing and 3D tracing,and between 2D Doppler and 3D Doppler(both P>0.05),and the correlations were both significant(r: 0.90,0.94,both P<0.001).Comparison of SV measured by tracing method and Doppler method: There were no statistical differences between SV measured by 2D tracing method and 2D Doppler method,and between 3D tracing method and 3D Doppler method(both P>0.05),and the correlations were both significant(r: 0.67,0.80,both P < 0.001).The correlations between SV measured by four methods and peripheral arterial blood flow ranged from weak to strong: two-dimensional tracing method(r= 0.61,P < 0.01),two-dimensional Doppler method(r=0.64,P < 0.01),three-dimensional Doppler method(r=0.71,P < 0.001),and three-dimensional tracing method(r=0.72,P <0.001).Comparison and correlation of SV measured by four methods and peripheral arterial blood flow between groups: Compared with group C,in group MR1,there were no statistical differences in SV measured by two-dimensional and three-dimensional tracing method(both P>0.05),and SV measured by two-dimensional and three-dimensional Doppler method significantly reduced(both P<0.001);SV measured by two-dimensional tracing and three-dimensional tracing showed an increasing trend(P<0.05～0.01),and SV measured by two-dimensional and three-dimensional Doppler method decreased significantly(both P<0.001).Compared with group MR1,in group MR2,SV measured by two-dimensional and three-dimensional tracing method showed an increasing trend(P<0.01～0.001),and the SV measured by two-dimensional and three-dimensional Doppler method decreased significantly(both P < 0.001).Compared with group C,the peripheral arterial blood flow in group MR1 and MR2 both decreased significantly(both P<0.001).Compared with group MR1,the peripheral arterial blood flow in group MR2 also decreased significantly(P<0.001).Correlation between SV measured by different methods and peripheral arterial blood flow in the case group(MR1+MR2): there was no statistical correlation between SV measured by two-dimensional tracing and peripheral blood flow(r=0.20,P>0.05),while the correlation between SV measured by the remaining three methods and peripheral blood flow ranged from weak to strong: three-dimensional tracing method(r=0.43,P<0.01),two-dimensional Doppler method(r=0.72,P<0.001)and three-dimensional Doppler method(r=0.73,P<0.001).Conclusion:1.In patients with MR,three-dimensional echocardiography is better than conventional two-dimensional echocardiography in the assessment of left ventricular stroke volume.2.Two-dimensional and three-dimensional Doppler method,especially three-dimensional Doppler method can also be used to evaluate left ventricular stroke volume.3.The left ventricular stroke volume measured by the three-dimensional Doppler method and the blood flow in the peripheral arteries of the limbs can reflect the effective left ventricular stroke volume to some extent.