Assessment of the ductus arteriosus in fetuses with tetralogy of Fallot and the implication for postnatal management

Association of right aortic arch and agenesis of ductus arteriosus in prenatal tetralogy of Fallot spectrum and its clinical implications

OBJECTIVE

In our center, we observed an increased frequency of right aortic arch (RAA) with an agenesis of the ductus arteriosus (ADA) in prenatally diagnosed tetralogy of Fallot (ToF) and its variations. This study aimed to determine whether there is an association of RAA and ADA in fetuses with ToF. Distribution of genetic anomalies and impact on postnatal outcome were further evaluated.

METHOD

Single-center retrospective observational study including pregnancies with prenatal diagnosis of ToF from 2010 to 2023. All cases were subdivided into ToF with pulmonary stenosis (PS) and pulmonary atresia (PA). Clinical and echocardiographic databases were reviewed for pregnancy outcome, genetic anomalies, and postnatal course.

RESULTS

The cohort included 169 cases, 124 (73.4%) with ToF/PS and 45(26.6%) with ToF/PA. Agenesis of the ductus arteriosus was significantly associated with RAA in both subtypes of ToF (p = 0.001) compared to left aortic arch and found in 82.5% (33/40) versus 10.7% (9/84) of fetuses with ToF/PS and in 57.1% (8/14) versus 12.9% (4/31) of fetuses with ToF/PA. In both ToF/PS and ToF/PA, RAA/ADA versus RAA/patent DA revealed a significantly higher risk for the presence of genetic abnormalities, especially microdeletion 22q11.2, major aorto-pulmonary collateral arteries and a shorter time to complete surgical repair.

CONCLUSION

We demonstrated a significantly increased frequency of RAA/ADA in patients with prenatally diagnosed ToF. Although this association revealed no significant impact on overall survival, the prenatal detection of RAA/ADA has implications for counseling, genetic evaluation and postnatal management.

The multiform sonographic spectrum of arterial duct in right aortic arch

To study the different characteristics of arterial duct (AD) in a series of prenatally detected right aortic arch (RAA). Out of 832 congenital heart diseases (CHD) referred to a tertiary center, 98 cases had RAA. Based on anatomical landmarks we identified 7 types of AD: type 1 left-sided, transverse; type 2 left-sided, vertical; type 3 from the underside of aortic arch (AA), vertical; type 4 right-sided, mirror-image “V”, transverse; type 5 right-sided, “H” shaped, transverse; type 6 bilateral; type 7 absent or unidentifiable. For each type of AD the incidence of associated major CHD was calculated and chi-square test was applied to verify the null hypothesis with significance level of p < 0.05. Type 1 occurred in 43% of cases including 4 with CHD and no cases with pulmonary outflow obstruction (POO). Symptoms of vascular ring were present in 41% of survivors. Type 2, 3 and 7 AD were associated with tetralogy of Fallot (TOF) or equivalents. No type 5 AD with CHD had POO and 3 isolated cases had asymptomatic hypoplasia of left pulmonary artery (LPA). Two type 6 AD had disconnection of LPA. Type 1 occurred more often as an isolated finding (p < 0.001), whereas types 2 (p = 0.0026), 3 (p = 0.0045), 4 (p = 0.0325) and 7 (p = 0.0001) were frequently associated with major CHD. In RAA, type 1 (U-shaped) is usually an isolated finding (p < 0.001) which includes all symptomatic vascular rings. POO is always present when the AD is vertical or absent but not when it lies on a transverse plane. Bilateral AD is rare and brings the risk of functionary loss of left lung if not identified.

Diagnostic analysis of abnormal increase of PASP in fetus in middle- and late-stage pregnancy by color Doppler echocardiography

OBJECTIVE

Our study was conducted with an attempt to investigate the diagnostic analysis of abnormal increase of fetal pulmonary artery systolic pressure (PASP) in middle and late pregnancy by color Doppler echocardiography.

METHODS

From August 2017 to January 2019, 52 fetuses with moderate or greater tricuspid high-speed regurgitation were retrospectively analyzed and selected as Group A. 88 fetuses with full-color blood flow of the two ventricles and symmetrical sizes of the cardiac cavities on both sides harboring tricuspid valve and mild regurgitation or a small amount of regurgitation were selected as Group B. The pulmonary artery blood flow acceleration time (AT) and right ventricular ejection time (ET) was measured, and the PASP was calculated.

RESULTS

The tricuspid regurgitation velocity, tricuspid regurgitation pressure difference and PASP in Group A were higher than those in Group B (p < 0.05), and the AT and AT/ET values in Group A were lower than those in Group B (p < 0.05). Gestational age, tricuspid regurgitation velocity and tricuspid regurgitation pressure difference were positively correlated with PASP. However, AT/ET and AT value were negatively correlated with PASP.

CONCLUSION

The abnormal increase of pulmonary artery can be assessed by color Doppler echocardiography of fetal tricuspid regurgitation, which is worth popularizing and applying in clinic.

ADVANCES IN KNOWLEDGE

It was suggested that the middle- and late-stage fetuses with moderate or greater tricuspid regurgitation and with >20 mmHg regurgitation pressure difference should be followed up in clinic. If PASP was ≥70 mmHg with symptoms of right heart failure, fetuses should be closely observed until 35-36 weeks old to ensure fetal safety and early delivery would be recommended.

Third trimester predictors of interventional timing and accuracy of fetal anticipatory guidance in tetralogy of Fallot: A multi-center study

OBJECTIVE

The objective was to evaluate and improve accuracy of anticipatory counseling regarding neonatal intervention for prenatally diagnosed tetralogy of Fallot (TOF) by assessing new and previously published predictors of neonatal intervention.

METHODS

This is a multi-center, retrospective study from three centers of 112 fetal TOF patients undergoing third trimester fetal echocardiograms from 2004 to 2017. Additional cardiac defects requiring neonatal intervention were excluded. Fetal echocardiographic, clinical, and consultation data were compared between neonatal and late intervention. Optimal echocardiographic values were determined.

RESULTS

Twenty-six infants (23%) required neonatal intervention. Those infants had significantly different pulmonary valve (PV) z-scores, PV:aortic valve (AoV) ratios, PV:AoV z-score differences (absolute difference between z-scores), and increased likelihood of abnormal ductal flow. Counseling during fetal echocardiogram regarding interventional timing was accurate for 50% needing neonatal intervention and 86% undergoing late intervention (P = .002). The best neonatal intervention predictors were PV:AoV ratio of <0.6 and counseling for neonatal intervention. PV:AoV z-score difference ≥5 provided 89% negative predictive value for excluding patients from neonatal repair.

CONCLUSIONS

Third trimester fetal echocardiograms can predict interventional timing. The best predictors of neonatal intervention are PV:AoV ratio <0.6, PV:AoV z-score difference ≥5, and cardiologist counseling that neonatal intervention was likely.

High incidence of ductal closure or narrowing at birth in patients with right ventricular outflow tract obstruction with normal orientation of the ductus arteriosus

BACKGROUND

Ductal patency is mandatory to manage patients with ductal-dependent pulmonary circulation. The aim of this study is to elucidate the morphological and haemodynamic features of ductus arteriosus with right ventricular outflow tract obstruction, and investigate the appropriate perinatal management.Patients and methodsPatients with prenatal diagnosis of right ventricular outflow tract obstruction at our institution between 2010 and 2015 were included in the study. Reverse orientation of the ductus arteriosus is defined as an inferior angle of 90°. We retrospectively reviewed the shape and flow pattern of ductus arteriosus and the clinical characteristics of the cases.

RESULTS

A total of 39 patients were enrolled. The shape was divided into normal orientation (n=15) and reverse orientation (n=24) of the ductus arteriosus. There was no significant difference in the type of oxygen saturation at birth and age at shunt operation between both the groups. However, the median narrowest diameter of ductus arteriosus in the normal orientation group was significantly smaller than that in the reverse orientation group (2.0 [1.0-5.4] versus 3.0 [1.3-4.4] mm, p&lt;0.05). In two patients of the normal orientation group, ductus arteriosus had closed at birth, and one of whom died because of severe cyanosis.

CONCLUSIONS

Normal orientation pattern might have high incidence of an early narrowing or closure of ductus arteriosus at birth. The critical patients need careful evaluation by repeated foetal echocardiography and further maternal interventions.

Ductus arteriosus and fetal echocardiography: Implications for practice

The ductus arteriosus (DA) is a crucial part of the fetal circulation, both in the normal fetus and in critical congenital heart disease (CHD). It allows shunting between the pulmonary and systemic circulations. In physiological prenatal conditions, the DA lets the majority of right ventricular output bypass the fluid-filled, high-resistance lungs. The DA can cause hemodynamic compromise in the fetus and neonate when constricted or absent (in isolation or in patients with CHD) and may lead to pre- or postnatal sequelae within other systems when forming part of a vascular ring. In CHD, the DA can be interrogated by fetal echocardiography to infer information regarding severity of pulmonary outflow tract obstruction, adequacy of the sub-pulmonary ventricle to supply pulmonary blood flow, and to predict the likelihood of atrial septum restriction in transposition of the great arteries. A good understanding of the DA is crucial for fetal cardiologists.

Utility of fetal cardiac magnetic resonance imaging to assess fetuses with right aortic arch and right ductus arteriosus

OBJECTIVE

To evaluate the utility of fetal cardiac magnetic resonance imaging (MRI) to diagnose right aortic arch (RAA) with right ductus arteriosus.

METHODS

This retrospective study included six fetuses with right aortic arch and right ductus arteriosus. The six fetal cases were examined using a 1.5-T magnetic resonance unit. The steady-state free precession (SSFP) and single-shot turbo spin echo (SSTSE) sequences were used to evaluate the fetal heart and airway. The gestational age of the six fetuses ranged from 22 to 35 weeks (mean, 26.5 weeks). The age of the pregnant women ranged from 23 to 40 years (mean 31 years).

RESULTS

Fetal cardiac MRI diagnosed the six fetal cases with RAA with right ductus arteriosus correctly. Among the six fetuses, four were associated with other congenital heart defects. In three of six cases, the diagnoses established using prenatal echocardiography (echo) was correct when compared with postnatal diagnosis.

CONCLUSIONS

Fetal cardiac MRI is a useful complementary tool to assess fetuses with RAA and right ductus arteriosus.

Neonatal management and outcomes of prenatally diagnosed CHDs

OBJECTIVES

The aim of this study was to determine the probability of intervention at birth after prenatal diagnosis of CHD.

METHODS

A 10-year retrospective study including all foetuses with a prenatally diagnosed CHD and those delivered in a tertiary-care cardiac centre between January, 2002 and December, 2011 was carried out. Patients were classified into eight groups according to the anticipated risk of neonatal intervention.

RESULTS

The need for urgent intervention and/or PGE1 infusion within the first 48 hours of life was 47% (n=507/1080): 72% (n=248) for CHD at risk for a Rashkind procedure, 77% (n=72) for CHD with ductal-dependent pulmonary flow, 13% (n=22) for CHD with potentially ductal-dependent pulmonary flow, 94% (n=62) for CHD with ductal-dependent systemic flow, 29% (n=88) for CHD with potentially ductal-dependant systemic flow, 50% (n=4) for total anomalous pulmonary venous connection, and 17% (n=1) for CHD with atrio-ventricular block. In all, 34% of the patients received PGE1 infusion and 21.4% underwent urgent catheter-based or surgical interventions; 10% of patients without anticipated risk (n=10) underwent an early intervention; 6.7% (n=73) of the patients died; and 55% (n=589) had an intervention before discharge from hospital.

CONCLUSION

Half of the neonates with foetal CHD benefited from an urgent intervention or PGE1 infusion at birth. We recommend scheduled delivery and in utero transfer for transposition of the great arteries, double-outlet right ventricle with sub-pulmonary ventricular septal defect, total anomalous pulmonary venous connection, CHD with atrio-ventricular block with heart rate <50, all ductal-dependant lesions, and CHD with potentially ductal-dependant systemic flow.