Study Of Myocardial Deformation And N-terminal Pro-brain Natriuretic Peptide In Umbilical Cord Blood And Their Correlation In Fetus With Hypertensive Disorders In Pregnancy

Objective:Hypertensive disorders in pregnancy (HDP)is a specific disease which occurs in pregnancy. The basic pathophysiological change is the spasm of small arteries all over the body, which causes increased peripheral vascular resistance, reduced-uteroplacental perfusion, leading to placental insufficiency which induce intrauterine growth retardation, intrauterine embarrass, even death. Placental insufficiency triggers fetal compensatory mechanisms and may finally lead to fetal cardiac compromise and inadequate tissue perfusion. In placental insufficiency, redistribution of fetal cardiac output, myocardial hypertrophy, altered cardiac diastolic and systolic function can be found. Fetal cardiac function evaluation is an important content of prenatal examination, and it is also the basis of clinical evaluation of disease and treatment..The routine technique of echocardiography could only estimate the global heart movement and could not evaluate effectively local myocardium movement. A recently developed new technique-velocity vector imaging (VVI)can examine fetal regional longitudinal contraction and relaxation by velocity, strain and strain rate and left ventricular twist, and can quantitatively evaluate cardiac diastolic and systolic function and regional myocardial movement. N-terminal pro-brain natriuretic peptide(NT-proBNP) has been studied as a biomarker for the diagnosis, evaluation and management of heart failure in recent years. It can be used to detect early myocardial lesion with high value. One aim of this study is to evaluate the fetal left ventricular and right ventricular parameters in HDP by VVI and to discuss the important clinical value of VVI in quantitatively evaluating regional longitudinal function of fetal heart. The other aim is to investigate the feasibility if NT-proBNP levels in fetal umbilical cord blood could estimate fetal cardiac function in perinatal period and to undersand its influence on fetal cardiac function in HDP.Methods:We examined respectively217pregnant women, including81cases of HDP and136normal fetuses. Fetuses in HDP were dividod into three groups:gestational hypertension(GH)24cases, mild preeclampsia(M-PE)25cases and severe preeclampsia(S-PE)32cases. Inclusion criteria for all subjects were accurate last menstrual period, singleton pregnancy. No obvious abnormality was found in fetal screening. Digital dynamic four-chamber images were collected in all fetuses. Five indexes below were obtained in twelve segments respectively to assess left ventricular and right ventricular longitudinal contraction and relaxation:systolic maximum velocity(Vs),diastolic maximum velocity(Vd), systolic maximum strain(S), systolic maximum strain rate(SRs), diastolic maximum strain rate(SRd). Every index was averaged from three heart cycles. ⅤⅥ parameters of fetuses in HDP were compared with those of normal fetuses. We detected NT-proBNP in umbilical cord blood after fetal disengagemented. NT-proBNP levels of fetuses in HDP were compared with those of normal fetuses. Correlation analyses were undertaken between NT-proBNP levels in umbilical cord blood and fetal variables、 parameters of ⅤⅥ and NT-proBNP levels in peripheral vein of pregnant women.Results:Because of fetal position and inaccurate tracking of endocardium of ventricular, digital dynamic four-chamber images in192cases were collected. Parameters of cardiac structure and function of routine echocardiography of fetuses in HDP were changed without statistical difference compared with those in normal feuses (P>0.05).Vs and Vd were both gradually decreased from the base segment to the apical segment in the left ventricle(LV) and right ventricle(RV)(P<0.05), whereas strain and strain rate were stable among all segments in each group (P>0.05)All the Vs、Vd、S、SRs and SRd in LV and RV were not changed markedly in gestational hypertension compared with those in normal fetuses (P>0.05).All the S、SRs and SRd in RV were obvious lower in mild preeclampsia compared with those in normal fetuses (P<0.05). All the Vs、Vd、S、SRs and SRd in RV were obviously higher than those in LV in gestational hypertension and mild preeclampsia. All the S、SRs and SRd in LV and RV were obvious lower in severe preeclampsia compared with those in normal fetuses, gestational hypertension and mild preeclampsia (P<0.05),Vd in RV was obvious lower in severe preeclampsia compared with those in normal fetuses and gestational hypertension(P<0.05).Vs and Vd in RV were obviously higher than those in LV (P<0.05), S. SRs and SRd in RV were similar with those in LV without statistical significance (P>0.05)NT-proBNP levels in umbilical artery were similar with those in umbilical vein in each group. NT-proBNP levels in umbilical cord blood of mild preeclampsia and severe preeclampsia were obviously higher compared with those in normal fetuses.. Analyses of variance between each group of the fetuses with HDP were significant(p<0.05). There were no statistically significant associations between NT-proBNP levels in umbilical artery and gestational age, birth weight, Apgar scores, newborn gender and the mode of delivery(p>0.05). There were no statistically significant associations between NT-proBNP levels in umbilical artery and Vs,Vd in LV and RV(p>0.05)。 There were negative correlations between NT-proBNP levels and S,SRs,SRd in LV and RV (P<0.05). NT-proBNP levels in umbilical cord blood were obviously higher than those in peripheral vein of pregnant women in each group. There was no statistically significant associations between NT-proBNP levels in umbilical cord blood and those in peripheral vein of pregnant women. Conclusions:1.VVI can quantitatively evaluate myocardial mechanics in fetus. Vs and Vd were both gradually decreased from the base segment to the apical segment in the LV and RV (P<0.05),whereas strain and strain rate were stable among all segments (P>0.05).2. HDP may cause changes of fetal cardiac function,developing with the severity of patient’s condition. The parameters of VVI and NT-proBNP levels in umbilical cord blood were not changed markedly in gestational hypertension. The parameters of VVI decreased as well as NT-proBNP levels in umbilical cord blood increased in mild preeclampsia and severe preeclampsia,which prompted that fetal cardiac function impaired.3. HDP may influence both fetal left cardiac function and right cardiac function, yet the decrease of parameters of RV was earlier than that of LV. The diastolic function decreased earlier than the systolic function.4. The parameters of VVI had changed before the indexes of routine echocardiography occurred abnormal. It indicated that VVI was a useful tool to evaluate early lesion of fetal heart.5. The elevated NT-proBNP concentrations in umbilical cord blood derive from the fetus themselves. It was feasible to estimate the fetal cardiac function by NT-proBNP in umbilical cord blood.