The Value Of Echocardiography In The Diagnosis And Postnatal Outcome Of Fetal Pulmonary Stenosis

BackgroundFetal congenital heart disease(CHD)was the most common malformations of fetal system screening,which was also one of serious birth defects.It occurred 4-13% in live births,and its mortality is about 20% of newborns or 50% of babies,and it could also increase 4 to 5 times incidence of intrauterine births.Simultaneously,it would bring huge mental and economical burdens to the family.Therefore,the precise prenatal diagnosis in the perinatal period and neonatal management is an early warning for FCHD.Fetal pulmonary stenosis(PS)was one of common CHDs,which occurs 10-20% of all CHDs.It could be single performance or with others intracardiac or extracardiac malformations or with chromosomal abnormalities.The fetal PS was easily missed in the fetal period,because of the fetal special hemodynamic characteristics involving fetal cardiovascular circulation system.However,some cases will get worse during pregnancy,and finally become the serious pulmonary artery stenosis which could cause right ventricular hypertrophy,narrow right ventricular cavity and even pulmonary atresia leading severe clinical symptoms and signs from the mild abnormality.Thus,it is a heated topic how to find fetal PS and its related diseases by the echocardiography as early as possible and precisely evaluate the outcome of fetal PS in order to offer a basis for treatment.Objectives1.We observed the structure of fetal pulmonary artery(PA)with two quantitative measurements(including PA(pulmonary valve,PV)/aorta(aortic valve,AV)rate and PA Z score)by echocardiography in order to discuss and analyze the prenatal echocardiographic features of fetal PS and the relationship between fetal PS and other intracardiac,extracardiac malformations and chromosomal abnormalities.2.We also analyzed the prenatal echocardiographic features of fetal PS,and follow up development during the whole pregnancy,and the prognosis and clinical outcomes after birth.Methods1.This retrospective study included 127 fetuses with fetal PS from 30382 cases of pren atal ultrasound screening from January 2014 to December 2016.First,the ultrasound gestational age was determined by measurements of fetal structures.Second,the fetal heart sections were scanned and routinely stored,and the 3D/4D spatiotemporal imaging correlation(STIC)was also used to acquire the real-time dynamic images.Finally,The fetal heart structure and hemodynamic change had been systemically tested,including the volumes of atria and ventricles,the diameters of PA(PV)and AO(AV)and their ratios,the Z-score of PA and comparing with ratio of PA(PV)/AO(AV),and then analyzed the difference of this two measurements in the diagnosis of fetal PS and the relationship with other intracardiac or extracardiac malformations or chromosomal abnormalities.2.Twenty-three cases with pure PS were selected from the 127 cases with fetal PS,the echocardiographic changes of fetal PS was analyzed,the postpartum echocardiography was also compared with the prenatal ultrasound.Finally,the changes of hemodynamics were also observed before and after delivery.Results1.127 fetuses were diagnosed with pulmonary stenosis in prenatal ultrasound in all 30382 fetuses,105 cases were confirmed by autopsy or postpartum echocardiography,13 cases were lost to follow-up,6 cases showed normal pulmonary artery diameter and blood flow with echocardiography,and 3 cases confirmed by autopsy showed aortic diameter increased and pulmonary diameter normal.The PA(PV)/AO(AV)ratio had higher positive rate than PA Z score in mild PS.Thirty-two cases(30.48%)of all 105 cases were pulmonary valve stenosis and 73 cases(69.52%)were pulmonary artery stenosis.Eighty-five cases(80.95%)were accompanied with heart deformity,of which most common were ventricular septal defect,tetralogy of Fallot and double outlet right ventricl e,and all the pulmonary artery stenosis cases combined with intracardiac or extracardiac malformations.Thirty-seven cases(35.24%)combined with extracardiac malformations,of which most common were single umbilical artery,urinary system malformation and neurological malformations.Twenty cases had no malformation and were diagnosed with pure pulmonary valve stenosis.Seven cases of 105 cases had chromosomal abnormalities and 3 cases were pulmonary artery valve stenosis and 4 cases were pulmonary artery stenosis.2.Twenty cases(86.96%)of 23 cases with pure PS were pulmonary valve stenosis,and the rest 3 cases were PS.Sixteen fetuses of 23 cases were normal delivery,but the other 7 cases were induced labor.And 5 cases of 7 cases confirmed by autopsy were with severe pulmonary valve stenosis and one case was with chromosomal abnormalities.The 16 newborns were confirmed by echocardiography,and 13 cases had different pulmonary valve stenosis: 9 cases were mild,1 case was moderate and 3 cases were severe.The mild to moderate pulmonary valve stenosis cases had good outcomes: the pulmonary gradient had no change in 5 cases,decreasing to normal in 2 cases and becoming worse in 2 cases.The severe pulmonary valve stenosis had worse outcomes,which could lead to heart failure.Three of 23 cases confirmed by postpartum echocardiography were as normal pulmonary artery.Conclusions1.Using both measurements to evaluate the fetal PS could improve its diagnostic accuracy.The pulmonary stenosis usually combined with aortic malformation and extracardiac malformations,especially in pulmonary stenosis.Pulmonary stenosis and chromosomal abnormalities also have a certain correlation,because combined with intracardiac malformations of fetal chromosomal aberration rate is higher than no malformation,and pulmonary stenosis with chromosomal abnormalities is higher than normal chromosomal.2.The severe pulmonary valve stenosis of fetuses had typical echocardiography,but the mild and moderate group could be missed.Therefore,fetal pure pulmonary stenosis need to be estimated in consideration with the inner diameter of PA,echo and movement from the PV,the right ventricle,right ventricular thickness,tricuspid regurgitation and ductus arteriosus,and also need to be monitored and followed up by prenatal and postpartum echocardiography,and thus to make the best decision in clinic.