| Objective:To quantitatively assess the differences of left ventricular energy loss(EL)and myocardial mechanics in patients with pre-hypertension(Pre-HT)using ultrasonic vector flow mapping(VFM)combined with two-dimensional speckle tracking imaging(2D-STI),and to reveal the spatio-temporal relations--hip between the left ventricular blood flow EL and myocardial mechanical deformation.Methods:This study included 43 subjects with Pre-HT(SBP 120-139 mmHg and/or DBP 80-89mmHg),58 newly diagnosed untreated HT(SBP≥140mmHg and/or DBP≥90mmHg),44 healthy subjects matched by gender and age with optimal blood pressure(SBP<120mmHg and DBP<80mmHg).Image acquisition and echocardiographic measurements were performed using the Hitachi Aloka Prosound F75 ultrasound system.Left atrial end-systolic diameter(LADs),left ventricular end-diastolic dimension(LVDd),inter-ventricular septal thickness(IVSTd),posterior wall thickness(PWTd)were measured.Peak blood flow velocities at the mitral valve were recorded in apical four chamber view during early filling(E peak)and in late diastole(A peak).The TDI imaging was used to evaluate the early(e peak)and late(a peak)diastolic maximal velocities of the septal and lateral mitral annuli in apical four-chamber view.Then E/A ratio、E/e ratio、e/a ratio were calculated.Left ventricular mass(LVM)was estimated by Devereux’s formula according to the American Society of Echocardiography simplified cubed equation.LVM was divided by body surface area(BSA)to obtain left ventricular mass index(LVMI).Acquired standard dynamic two-dimensional echocardiographic imag-es and standard dynamic Doppler flow images of apical four-chamber,three-chamber and two-chamber.All images were acquired in three consecutive cardiac cycles.The flow EL of left ventricle during isovolumic relaxation(IVR)phase,rapid filling(RF)phase,slow filling(SF)phase and atrial contraction(AC)phase were acquired with a dedicated VFM workstation.Also,Early diastolic and late diastolic longitudinal strain rate(LSR)were derived with 2D-STI in apical four-chamber,three-chamber and two-chamber during the same cardiac cycle with the same derived workstation.Both the average values of EL and LSR were calculated of the three chambers.Correlation analysis were performed among early diastolic and late diastolic EL,general functional parameters of left ventricular relaxation and the mechanical deformation.Results:1、General parametersThere were no differences in age,sex,BSA,heart rate among the three groups(P>0.05).Systolic blood pressure(SBP)and diastolic blood pressure(DBP)of two case groups were much higher than those in control group(P<0.01);compared with those in Pre-HT group,SBP and DBP of HT group were significantly higher(P<0.01).2、Two-dimensional echocardiography and Doppler ultrasound measurement Pre-HT group and control group:There were no significant differences of LADs,IVSTd,PWTd,LVDd and LVMI between control group and Pre-HT group(P>0.05).Compared with those in control group,A peak was higher and E/A was lower in Pre-HT group(P<0.05 or P<0.01).HT group and control group:LADS,IVSTd,PWTd and LVMI were much higher in HT group than those in control group(P<0.01).Compared with those in control group,A peak、E/e were higher and e peak、E/A、e/a were lower in HT group(P<0.01).Pre-HT group and HT group:LADs、PWTd、LVMI were higher in HT group than those in Pre-HT group(P<0.01).Besides,compared with those in Pre-HT group,E/e was much higher(P<0.01)and e peak was lower in HT group(P<0.01).There were no differences of LVDd、E peak、LVEF among the three groups(P>0.05).3、Left ventricular mechanical deformation with 2D-STI Pre-HT group and control group:Early diastolic and late diastolic LSR of Pre-HT group were much lower than those in control group(P<0.01).HT group and control group:Early diastolic and late diastolic LSR of HT group were much lower than those in control group(P<0.01).Pre-HT group and HT group:There were no differences of early diastolic and late diastolic LSR between Pre-HT group and HT group(P>0.05).4、Left ventricular EL with VFM Pre-HT group and control group:The P4-EL was significantly higher in Pre-HT group than that in control group(P<0.01).HT group and control group:The P4-EL was significantly higher in Pre-HT group than that in control group(P<0.01).Pre-HT group and HT groupThe P4-EL was significantly higher in HT group than that in Pre-HT group(P<0.01).There were no differences of P1-EL、P2-EL、P3-EL among the three groups(P>0.05).5、Correlations(1)Correlation analysis between flow EL during RF、AC and general diastolic functional parameters of left ventricle:Univariate correlation revealed that in control group the P2-EL was positively correlated with E peak、E/e(r_s=0.574、0.311,P<0.05 or P<0.01);P4-EL was positively correlated with A peak(r_s=0.440,P<0.01).Univariate correlation revealed that in Pre-HT group the P2-EL was positively correlated with E peak、e peak(r_s=0.720、0.360,P<0.05 or P<0.01);P4-EL was positively correlated with A peak、E/e(r_s=0.452、0.382,P<0.05 or P<0.01).Univariate correlation revealed that in HT group the P2-EL was positively correlated with E peak、e peak(r_s=0.759、0.597,P<0.01);P4-EL was positively correlated with A peak、E/e(r_s=0.780、0.449,P<0.01);and negatively correlated with e peak(r_s=-0.494,P<0.01).(2)Correlation analysis between flow EL during RF、AC and myocardial mechanical deformation of left ventricle:Univariate correlation revealed that in control group the P2-EL was positively correlated with GLSRe(r_s=0.277,P<0.05).Univariate correlation revealed that in Pre-HT group the P2-EL was positively correlated with GLSRe(r_s=0.341,P<0.01);P4-EL was positively correlated with GLSRa(r_s=0.386,P<0.01).Univariate correlation revealed that in HT group the P2-EL was positively correlated with GLSRe(r_s=0.529,P<0.01);P4-EL was positively correlated with GLSRa(r_s=0.266,P<0.05).Conclusions:1、The patients with Pre-HT already existed higher P4-EL even with normal left ventricular geometry.With further elevation of blood pressure,the left ventricular geometry changed and P4-EL was much higher in patients with HT.2、Left ventricular mechanical deformation was decreased in various extent in Pre-HT group and HT group.3、The flow EL was affected by the changes of left ventricular mechanical deformation and diastolic function.4、The flow EL parameter could reflect the changes of left ventricular diastolic function,it was expected to become a new technology to assess the left ventricular diastolic dysfunction in patients with Pre-HT. |
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