| Objective: To explore the significance of cardiac axis determination in screening during 11-13+6 gestational weeks of fetal congenital heart disease. Methods : The subjects for study were fetuses being measured neck transparency layer thickness in our hospital between June 2014 and December 2014. Selection criteria: single fetuses of crown-rump length 45-84mm(approximately 11-13+6 pregnant week), and the body mass index(BMI) of the pregnant mother less than 30. Exclusion: Pregnant women rejecting the scheme, or out of contact, or of pregnancy termination or abortion. All fetuses were estimated a gestation period according to the crown-rump length, and were divided into 3 groups. Two-dimensional ultrasonography checkup and combined checkup using two-dimensional ultrasonography and color Doppler flowing imaging were made to the fetuses to make the comparison: group 1, 11-11+6 week fetuses(45-57 mm in crown-rump length) 61 fetuses or times; group 2, 12-12+6 week fetuses(58-70 mm in crown-rump length) 60 fetuses or times; group 3, 13-13+6 week fetuses(71-84 mm in crown-rump length) 53 fetuses or times. Two-dimensional ultrasonography checkup and combined checkup using two-dimensional ultrasonography and color Doppler flowing imaging were made to all the fetuses to measure the cardiac axis. Among them, 11 cases of fetuses were measured once a week in 3 consecutive weeks in11-11+6 week, 12-12+6 week and 13-13+6 week. All pregnant women received echocardiography check up in their mid-term pregnancy. Concerning the cardiac axis value of fetuses with or without CHD obtained in early-term checkup, SPSS13.0 was used to make related statistics and analysis. Results: 152 fetuses were selectedfor the study. Maximum age of subjects was 42 years old, minimum age of the subjects was 18 years old, the average age was 28.4 years old.(1) Cardiac axis show rate by the 2 methods: 174 times of cardiac axis measure were made to 152 fetuses, the show rate for ultrasonography checkup was 61.5%, and the show rate for combined checkup was 78.8%, results of the 2 methods differed greatly, with P<0.01. The data according to pregnancy week subgrouping were: cardiac axis show rateswere considerably low for 11-11+6 week, 27.9% and 57.4% for ultrasonography checkup and combined checkup respectively, results differed obviously, with P<0.01. When it came to the 12-12+6 week, the show rates increased obviously, 65.0% and 85.0% for ultrasonography checkup and combined checkup respectively, results differed obviously, with P<0.01. When it came to the 13-13+6 week, show rates for both methods were highest, reaching 96.2%, results of the 2 methods were free from discrepancy.(2) The cardiac axis angle and dynamic change of the normal hearts in each pregnancy week: 44.5±4.2°for 11-11+6 week, 46.3±4.1°for 12-12+6th week, and 47.2 ± 3.7for 13-13+6 week, cardiac axis summary of the 3 groups was 46.1±4.1°. The 3 consecutive weeks dynamic observation of the normal hearts shows that cardiac axis angle increases as timegoes, yet it increases less and less as time goes.(3) The cardiac axis value of the abnormal hearts with CHD: For the 7 cases of fetuses with CHDin 11-13+6 week checkup, cardiac axis could be shown for 6 cases and failed to be shown for one case. Of the 6 showcases, no value fell between the 25 th percentile and the 75 th percentile value of the normal cardiac axis value. The details of the cardiac axis value were as follows: 2 cases were less than the 10 th percentile, which were aortic stenosis(AS) and truncus arteriosus(TA) respectively; one case was between the 10 th and the 25 th percentile, which was pulmonary regurgitation plus aortic regurgitation(PR+AR); one case was more than the 90 th percentile, which was tetralogy of fallot plus avsd atrioventricular septal defect(TOF+AVSD); one case was between the 75 th and the 90 th percentile, which was corrected transposition of great arteries(CTGA); one case was tetralogy of fallot plus pulmonary atresia(TOF+PA), which was measured once a week in three consecutive weeks, and the cardiac axis value was between the 75 th and the 90 th percentile for 11-11+6 week and 12-12+6 week and exceeded the 90 th percentile for 13-13+6 week. The remaining case failed to show the cardiac axis clearly, the mid-term echocardiography showed it suffered from the complex abnormality of single ventricle plus pulmonary stenosis and plus transposition of the great arteries(SV+PS+TGA). Conclusion:(1) It is feasible to measure fetuses’ cardiac axis using ultrasonography in 11-13+6 week pregnancy.(2) Combined checkup using two-dimensional ultrasonography and color Doppler flowing imaging can enhance the show rate of cardiac axis ofearly-term pregnancy, generally limit the date of measuring the cardiac axis within the diastole, and thus decrease the error of the measure.(3) The dynamic change rule of fetuses cardiac axis of 11-13+6 week is that it rotates leftward, and spread of the rotation lessens as time goes.(4) The relative safety range of fetuses’ cardiac axis of 11-13+6 week is between the 25 th and the 75 th percentile.(5) The abnormality of cardiac axis in early-term pregnancy is shown in the abnormality in leftward rotation angle and in rotation regularity. Whether the CHD will cause cardiac axis to change and how the cardiac axis will change depend on the types of the CHD.(6) Using cardiac axis measure method to sift fetuses’ CHD in early-term pregnancy is simple and feasible. Without adding checkup times and expenses of pregnant mothers, we can advance the date of sifting CHD into the early-term pregnancy, so as to gain sufficient time for clinical doctors and pregnant mothers themselves to make proper choices, which is of great clinical significance. |
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