Aorta larger than pulmonary artery in the fetal 3-vessel view

Patterns of Aortic Dilation in Tetralogy of Fallot: An Analysis of 100 Fetal Echocardiograms Compared With Matched Controls

Background Although aortic dilation is common in tetralogy of Fallot (TOF), its progression and risk of dissection are not well understood. The mechanism of dilation is primarily attributed to increased flow in utero; an alternative is unequal septation of the truncus arteriosus resulting in a larger aorta and inherently hypoplastic pulmonary artery (PA). If the latter is true, we hypothesize the aorta to PA ratio in TOF is stable throughout gestation, and sums of great artery dimensions are similar to controls. Methods and Results We performed a single-center retrospective study of fetuses with TOF (2014-2020) and matched controls. We compared sums of diameters, circumferences, and cross-sectional areas of the aorta and PA and evaluated the aorta to PA ratio across gestation in 2 TOF subtypes: pulmonary stenosis and atresia (TOF-PA). There were 100 echocardiograms with TOF (36% TOF-PA) with median gestational age of 31 weeks (interquartile range 26.5-34.4) and median maternal age of 34 years (interquartile range 30-37). There were no differences in sums of great artery dimensions between TOF-pulmonary stenosis and controls. In TOF-PA, sums were significantly lower than controls (P values <0.01). The aorta to PA ratio was stable throughout gestation (Pearson's r=0.08 [95% CI, -0.12 to 0.27], -0.06 [95% CI, -0.25 to 0.14]). Conclusions The aorta in fetal TOF is large but grows proportionally throughout gestation, with sums of great artery dimensions similar to controls. TOF-PA appears distinct from TOF-pulmonary stenosis (with smaller sums), warranting further investigation. In conclusion, our findings suggest an intrinsic developmental mechanism contributes to aortic dilation in TOF.

Smart-planes fetal heart (S-planes FH) software to quantitative evaluate the fetal great arteries

OBJECTIVES

To explore the feasibility of applying smart-planes fetal heart (S-Planes FH) to 3D volumes to generate and display the outflow tract views (OFTVs) and evaluate its agreement and reliability in determining fetal vessel dimensions.

METHODS

A total of 147 normal fetuses in the second or third trimester were enrolled. Once conventional 2D sonographic examination was finished, one or more 3D static volumes were then acquired in the 4-chamber view (4CV). The OFTVs automatically generated and displayed via a simple offline operation using S-Planes FH software. Per fetus, a single qualified S-Planes FH image was selected by an expert. The inner diameters of the aorta (AO) and pulmonary artery (PA) were measured in 2D and S-Planes FH images, respectively. The agreement and reliability of the two methods were verified by the Bland-Altman method and the intraclass correlation coefficient (ICC), respectively.

RESULTS

A total of 515 3D static volumes were successfully acquired in 147 fetuses. The OFTVs were generated and displayed using S-Planes FH in 138 (93.9%) cases. S-Planes FH had good agreement in measuring the diameters of great arteries (95% CI of limits, -0.9419 to 1.1464 for AO diameter, -0.8871 to 1.7007 for PA diameter). The intraobserver and interobserver ICCs in this study were greater than 0.81, indicating almost perfect reliability of the two methods with regard to observers.

CONCLUSIONS

S-Planes FH software is a feasible method for generating OFTVs as well as determining vessel dimensions in the second and third trimesters and had good agreement with 2D examination. Therefore, it possesses clinical value in screening for CHD and can be operated by different sonographers.

The effect of the introduction of the three-vessel view on the detection rate of transposition of the great arteries and tetralogy of Fallot

OBJECTIVES

The aim of this study was to analyze the annual detection rate (DR) of transposition of the great arteries (TGA) and tetrology of Fallot (ToF), after the introduction of the three-vessel view as a mandatory plane in 2012.

METHODS

All registered TGA and ToF cases were retrospectively extracted from our registry between 2007 and 2016. We compared the DR in a 10-year period, before 2011, with the DR of TGA and ToF after 2012.

RESULTS

In the period before 2012, 23 of the 52 TGA cases were prenatally detected (44.2%), compared with 42 of the 51 cases (82.4%) after 2012. For ToF, the DRs increased from 28 of 64 cases (43.8%) to 42 of 62 cases (67.7%) in the aforementioned periods. The increase in DRs for both defects was statistically significant (P ≤ 0.001 and P ≤ 0.05).

CONCLUSIONS

In this nationally organized prenatal screening program with a quality monitoring system and a uniform protocol, DRs of 82.4% for TGA and 67.7% for ToF were reached after the introduction of the three-vessel view as a mandatory item. The three-vessel view significantly contributes to the detection of these conotruncal anomalies.

Fetal aorta larger than the main pulmonary artery on the three-vessel view: Correlation with postnatal echocardiographic findings

PURPOSE

This study investigated postnatal cardiac anomalies determined by postnatal echocardiography in fetuses with the ascending aorta (AA) diameter larger than that of the main pulmonary artery (MPA) on the three-vessel view (3VV).

METHODS

The study included 17 pregnancies. The diameters of the AA and MPA were assessed on the 3VV in second-trimester sonographic screening, and all the patients underwent postnatal echocardiography to assess the cardiac outcome.

RESULTS

In the study population, the mean AA diameter was 3.7 mm (range, 2.2-5.6 mm), and the mean MPA diameter was 3.2 mm (range, 1.8-5.2 mm). The mean AA/MPA ratio was 1.2 (range, 1.1-1.9). According to the postnatal echocardiograms, one of the patients had tetralogy of Fallot. This patient had the highest prenatal AA/MPA ratio (1.9). Among the remaining 16 cases, five had secundum atrial septal defects, with two having concomitant dilatation of the AA. There was one case of isolated dilatation of the AA.

CONCLUSIONS

Although an AA with a diameter larger than that of the MPA on the 3VV does not usually indicate severe congenital heart disease involving the ventricular outflow tract and/or great arteries, careful prenatal and postnatal echocardiographic examinations are mandatory to determine the presence of congenital heart disease. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:423-428, 2016.

Role of the 3-Vessel and Trachea View in Antenatal Detection of Tetralogy of Fallot

Prenatal diagnosis of tetralogy of Fallot remains less frequent compared to other major congenital heart defects. In this study, we examined how often the 3-vessel and trachea view was abnormal in a large series of prenatally diagnosed cases of tetralogy of Fallot. In addition, we compared its sensitivity to that of the traditional outflow tract views for detection of tetralogy of Fallot. We found that both views were abnormal in all fetuses with tetralogy of Fallot, showing reversed aortic-to-pulmonary valve and aortic arch isthmus-to-ductus arteriosus ratios in the outflow tract and 3-vessel and trachea views, respectively. However, as a single measured marker, the enlarged aortic arch isthmus on the 3-vessel and trachea view appears to be the most sensitive for tetralogy of Fallot.

Simultaneous real-time imaging of four-chamber and left ventricular outflow tract views using xPlane imaging capability of a matrix array probe

OBJECTIVES

To determine the feasibility and reliability of using xPlane imaging to examine simultaneously the four-chamber and left ventricular outflow tract (LVOT) views in real time, to assess rotation angles from the four-chamber view to the LVOT view, and to investigate factors affecting the angles.

METHODS

In 145 fetuses at 11-37 weeks' gestation, we visualized the four-chamber view in one of three cardiac positions: a subcostal view with the apex at the 3 or 9 o'clock position; an apical view with the apex at the 12 or 6 o'clock position; or a view with the fetal heart apex midway between these two positions. We then used the rotation function of xPlane imaging, using the four-chamber view as the reference plane, to visualize the LVOT view simultaneously in real time on the secondary image plane, on the right side of the split screen, by rotating a reference line from 0° with a rotation step of 5°. The rotation angle necessary for the first appearance of LVOT was recorded as the first rotation angle. The reference line was then rotated until the LVOT was just out of view, and this last rotation angle was recorded as the second rotation angle. The difference between these two angles was recorded as the angle span of the LVOT display. Reliability was assessed by intraclass correlation coefficient (ICC).

RESULTS

Of the 145 fetuses examined, 29 had cardiac defects. Using xPlane imaging, the LVOT was visualized successfully after 14 weeks in 95.1% of cases. The first and second rotation angles varied significantly with cardiac position (P < 0.001); when the fetal heart was examined using a subcostal approach with the apex at the 3 or 9 o'clock position, the first rotation angle was smaller than that at the apical view for normal hearts (20° vs. 50°, P < 0.001). There was also a significant difference for the second rotation angle and for the angle span, between fetuses with and without normal LVOT (P = 0.038 and 0.006, respectively). Regarding intra- and interobserver reliability for measurement of first and second rotation angles, the ICCs were high (range, 0.847-0.980).

CONCLUSION

Using xPlane imaging, it is feasible to examine simultaneously the four-chamber and LVOT views in real time, and measurement of the rotation angles between these two views is reproducible. The rotation angles depend on the position of the fetal heart, and the normality of the LVOT. Proposed algorithms for examination of the fetal heart with three-/four-dimensional ultrasonography may need to be adapted to optimize visualization of the standard planes.

Application of the 3-vessel view in routine prenatal sonographic screening for congenital heart disease

OBJECTIVES

The purpose of this study was to evaluate the diagnostic accuracy of prenatal screening for congenital heart disease (CHD) based on a combination of the 4-chamber view and 3-vessel view in an unselected population.

METHODS

A prospective study on 8025 scanned fetuses was performed. All singleton pregnancies scheduled for routine prenatal sonographic screening at 20 to 24 weeks' gestation and subsequently delivered in our unit were included. Data were recorded regarding visualization of the 4-chamber view, outflow tracts, and 3-vessel view. Suspected CHD was confirmed by postmortem or postnatal echocardiography. We obtained follow-up data for the neonates and calculated the diagnostic accuracy of the examinations.

RESULTS

Major CHD was identified in 32 cases (4.0%), of which 26 (81.3%) were diagnosed antenatally and 6 (18.7%) postnatally. Four cases (0.5%) had false-positive findings. Twenty-one cases were identified by the 4-chamber view and 5 by an abnormal 3-vessel view. The sensitivity of the 4-chamber view alone was 65.6%, and the specificity was 99.9%. The sensitivity of the combination of the 4-chamber view and 3-vessel view was 81.3%, and the specificity was 99.9%.

CONCLUSIONS

The 3-vessel view is a reliable and easy method to be used in a routine antenatal clinic along with the 4-chamber view.