[Isolated right aortic arch: prenatal diagnosis characteristics, pregnancy outcomes and systematic review]. / Crosse aortique droite isolée : caractéristiques du diagnostic anténatal, issues de grossesses et revue de la littérature.

OBJECTIVE: To investigate prenatal diagnosis characteristics and pregnancy outcomes associated with isolated right aortic arch (RAA). METHODS: A retrospective study including fetuses with isolated RAA, managed between January 2010 and February 2018. Cases were identified from the ultrasound databases of the expert pediatric cardiologists, who made the aforementioned diagnosis. All fetuses were examined by a fetal medicine imaging expert to exclude any extracardiac abnormality. A systematic review was performed to assess the prenatal diagnosis and outcomes of fetuses with isolated RAA. RESULTS: Fifty-six fetuses were diagnosed with an isolated RAA. An isolated double aortic arch (DAA) was diagnosed in one fetus. Mean gestational age at diagnosis was 24 weeks. The sex ratio (boy/girl) was 0.89. No significant abnormality was detected in invasive tests (karyotype and FISH or microarray). Only one fetus was misdiagnosed with isolated RAA. He was the only symptomatic (stridor) newborn baby and was later diagnosed with DAA. Four studies were included in our systematic review representing 115 cases of isolated RAA. One significant chromosomal abnormality was detected: a 22q11 deletion in a newborn baby who had a postnatal finding of a soft palate cleft. There was one major obstetric complication: an intrauterine fetal demise at 41 gestational weeks. CONCLUSION: Diagnosis of isolated RAA can be challenging. Invasive tests are to be discussed. The diagnosis of isolated RAA should not change obstetric monitoring. Nevertheless, an echocardiography should be performed systematically in these new newborn babies within their first month of life.

Neonatal magnetic resonance imaging in double aortic arch diagnosed prenatally by ultrasound.

Congenital double aortic arch (DAA) is an uncommon vascular anomaly; however, its prenatal detection is associated with congenital heart defects and chromosomal abnormalities, including 22q11 deletion. We present a case of DAA diagnosed prenatally. DAA can be diagnosed by prenatal ultrasound in the transverse three vessel-trachea view, which shows a trident image formed by a complete vascular ring and the ductus arteriosus. Postnatal magnetic resonance images in this view correlate well with prenatal ultrasound images and help in confirmation of diagnosis, evaluation of the risk of airway or esophageal compression, and planning of surgery.

Fetuses with right aortic arch: a multicenter cohort study and meta-analysis.

OBJECTIVES: Use of recent antenatal screening guidelines for cardiac abnormalities has increased fetal diagnoses of right aortic arch (RAA). We aimed to establish the outcome of fetal RAA without intracardiac abnormalities (ICA) to guide postnatal management. METHODS: In the retrospective cohort part of our study, outcome measures were rates of chromosomal abnormalities, 22q11.2 deletion, fetal extracardiac abnormalities (ECA), postnatal ICA and ECA, and symptoms of and surgery for vascular ring. A systematic review and meta-analysis was also performed; results are reported as proportions. Kaplan-Meier analysis of vascular ring cases with surgery as endpoint was performed. RESULTS: Our cohort included 86 cases; 41 had a vascular ring. Rates of chromosomal abnormalities, 22q11.2 deletion and fetal ECA were 14.1%, 6.4% and 17.4%, respectively. Sixteen studies including our cohort (312 fetuses) were included in the systematic review. Overall rates of chromosomal abnormalities and 22q11.2 deletion were 9.0% (95% CI, 6.0-12.5%) and 6.1% (95% CI, 3.6-9.3%), whilst the respective rates for cases with no ECA were 4.6% (95% CI, 2.3-7.8%) and 5.1% (95% CI, 2.4-8.6%). ECA were seen in 14.6% (95% CI, 10.6-19.0%) prenatally and in 4.0% (95% CI, 1.5-7.6%) after birth. Postnatal ICA were identified in 5.0% (95% CI, 2.7-7.9%). Rate of symptoms of vascular rings (follow-up ≥ 24 months postpartum) was 25.2% (95% CI, 16.6-35.0%), and 17.1% (95% CI, 9.9-25.7%) had surgery. Two-year freedom from surgery was 83.0% (95% CI, 74.3-90.1%). CONCLUSIONS: Fetal RAA without ICA is more frequently associated with ECA than with chromosomal abnormalities. Most cases, however, are isolated. Vascular-ring symptoms occur in about 25% of cases. Postnatal surveillance is required mainly in the first 2 years after delivery.

How frequent is the fifth arch artery?

Although usually shown in embryology textbooks, the presence of the fifth pair of pharyngeal arch arteries has long been controversial. To the best of our knowledge, six pairs of bilaterally symmetrical arteries developing within the pharyngeal arches are yet to be found in any mammalian or avian species. Collateral channels between the distal ends of the fourth and sixth arch arteries, in contrast, have been found in up to half of all developing mouse embryos. In only one human embryo, again to the best of our knowledge, has a channel been found that extends from the aortic sac to the dorsal aorta, and hence qualifies as an arch artery. Despite these confounding factors in terms of the developmental heritage of the fifth arch arteries, the purported channels are invoked with increasing frequency to describe various lesions discovered in the setting of the congenitally malformed heart. Persistence of the artery of the fifth arch was initially proposed to explain double-barrelled aorta. It was subsequently proposed to account for various systemic-to-pulmonary channels feeding the pulmonary circulation in the setting of pulmonary atresia. It has also been claimed to persist so as to explain abnormal branching of the brachiocephalic arteries from the aortic arch. In the light of the ongoing doubts concerning the existence of the arteries of the fifth arch themselves, we have reviewed the various descriptions of purported fifth arch arteries within the world literature. We have then sought to validate the descriptions on the basis of our own understanding of development, for this purpose providing images of the remoulding arch arteries in the mouse so as to substantiate our conclusions. While accepting that our own interpretations are speculative, we suggest that more convincing alternative explanations can be advanced to account for the majority of lesions currently interpreted on the basis of persistence of the arteries of the fifth arches. Although the interpretations do not necessarily change the therapeutic approaches to the channels, appropriate description is important in terms of their classification.

Right aortic arch diagnosed antenatally: associations and outcome in 98 fetuses.

OBJECTIVE: To analyse the main characteristics, associated conditions and outcome of right aortic arch (RAA) detected in fetal life, and to assess if further investigation is required in cases of isolated RAA. METHODS: Retrospective observational study of all fetuses diagnosed with a RAA between 2004 and 2012 at a tertiary centre for fetal cardiology. RESULTS: A RAA was identified in 98 fetuses: 27 had normal intracardiac anatomy and 71 were associated with other congenital heart disease (CHD); conotruncal anomalies being the most common. An aberrant left subclavian artery was diagnosed in 18.4% of cases, a double aortic arch in 6.1%, and 12.2% had a vascular ring confirmed after birth. Overall, an extracardiac anomaly was present in 31.6% of the patients and a chromosomal anomaly in 15.3%, with half of the latter cases being 22q11.2 microdeletion. Extracardiac and chromosomal anomalies were more commonly associated with RAA with structural CHD (39.4% and 19.7%, respectively), compared to cases of RAA with normal intracardiac anatomy (11.1% and 3.7%, respectively) (p<0.05). First year mortality was 10.3%, with all deaths being in cases with associated structural CHD. CONCLUSIONS: Detailed fetal extracardiac examination should be undertaken in all cases of RAA. Isolated RAA has a good prognosis, and in the majority of the patients it is an asymptomatic vascular variant with a relatively low risk for chromosomal anomaly. The prognosis of RAA with CHD depends on the complexity of the CHD and/or the associated extracardiac anomalies. In these cases, there is a higher risk for chromosomal anomaly, particularly 22q11.2 microdeletion.

Clarification of the identity of the mammalian fifth pharyngeal arch artery.

The remodeling of the pharyngeal arch arteries is a complex process that occurs across vertebrates, although the specific number of arteries varies across species, with six in fish, but only five in birds and mammals, although they are numbered one through four, and six. The existence of a fifth arch artery in mammals has been debated for more than a century. Although some have doubted, and continue to doubt, its existence, several cardiovascular malformations can be explained only on the basis of its presence. We have analyzed the developing pharyngeal arch arteries in mouse and human embryos, using high-resolution episcopic microscopy. We have then created three-dimensional models, allowing us to identify any structures that would satisfy the descriptions of fifth arch arteries. This detailed examination revealed collateral channels connecting the fourth and sixth pharyngeal arch arteries in approximately half of the mouse embryos examined. Such collateral channels were seen in only one human embryo of eight examined by high-resolution episcopic microscopy, although we had previously identified such collateral channels using wax plate reconstruction. An extra vessel, occupying a discrete component of the pharyngeal mesenchyme, and therefore resembling a true fifth pharyngeal arch artery, was observed in one Carnegie Stage 14 human embryo. The pharyngeal mesenchyme in the human, therefore, can contain a fifth arch, with a contained artery, albeit transiently. Persistence of this structure, and the observed collateral channels, provides mechanisms to explain the congenital cardiovascular malformations described as persistent fifth aortic arch, and double-barreled aorta.

A novel way of visualizing the ductal and aortic arches by real-time three-dimensional ultrasound with live xPlane imaging.

OBJECTIVE: To describe a novel method of visualizing the ductal and aortic arches by real-time three-dimensional echocardiography with live xPlane imaging. METHODS: Live xPlane imaging was used to display the ductal- and aortic-arch views in 107 women with singleton pregnancies, including seven cases with suspected congenital heart defects (CHDs). The three vessels and trachea (3VT) view was obtained in such an orientation that either the pulmonary artery or the aorta was parallel to the direction of the ultrasound beam. The xPlane reference line was then placed across the targeted vessel, which in a normal case would provide an image of the corresponding arch view as a dual-image display. RESULTS: Once the 3VT view had been obtained, live xPlane imaging showed the aortic and ductal arches in all 100 normal cases. In seven cases with suspected CHD, the 3VT view was abnormal in five cases and normal in the other two. However, the ductal-arch view demonstrated by live xPlane imaging was abnormal in five cases of conotruncal anomalies and normal in two cases in which conotruncal anomalies were excluded. CHDs were confirmed at autopsy following termination of pregnancy in five cases and on postnatal echocardiography in one case. The heart was found postnatally to be normal in one case of suspected CHD; in this case live xPlane imaging showed that the observed abnormal 3VT view was caused by a tortuous course of the thoracic aorta associated with an abnormal diaphragm. CONCLUSION: Live xPlane imaging is a novel and relatively simple method of visualizing the ductal- and aortic-arch views, and may potentially be a useful tool in the screening of fetal conotruncal and aortic-arch anomalies.

Embryology and imaging review of aortic arch anomalies.

Congenital malformations of the thoracic aorta can be discovered on chest radiographs when associated with symptoms or found incidentally. We review the imaging anatomy and associations of many of the aortic arch malformations that can be encountered in adults and highlight key points with regard to their treatment and prognoses. An understanding of the normal and abnormal embryologic development of the aortic arch, with knowledge of their imaging features, may be important for improving diagnostic accuracy and patient care.

Aberrant right subclavian artery at 16 to 23 + 6 weeks of gestation: a marker for chromosomal abnormality.

OBJECTIVES: This study was carried out to determine the feasibility of defining the position of the right subclavian artery (RSA) by fetal echocardiography between 16 and 23 weeks of gestation, and the association between an aberrant right subclavian artery (ARSA) and chromosomal and cardiac defects. METHODS: We examined the position of the RSA in all patients who attended our unit for a fetal cardiac scan. The assessment was carried out using a transverse view of the fetal chest sweeping up from the level of the aortic arch, using color flow mapping. An ARSA was diagnosed when this vessel was not seen in the normal position and an arterial vessel was seen crossing behind the trachea towards the right arm, arising as a fourth branch of the aortic arch, at a lower level than normal. RESULTS: The course of the RSA could be identified in more than 95% of the 2799 fetuses examined between 16 and 23 + 6 weeks of gestation. An ARSA was found in 43 fetuses. The incidence was 1.5% in normal fetuses, 28.6% in fetuses with trisomy 21, 18.2% in fetuses with trisomy 18 and 8% in fetuses with other chromosomal defects. There was an association between an ARSA and cardiac defects in seven of the 43 fetuses (16%), and three of these seven fetuses had a normal karyotype. CONCLUSIONS: Assessment of the RSA by a fetal cardiologist is possible in almost all cases. The finding of an ARSA is much more common in fetuses with chromosomal defects, in particular trisomy 21 (where the prevalence of an ARSA was 29%), compared with euploid fetuses. Moreover, the presence of an ARSA may be associated with an increased incidence of intracardiac malformations. Examination of the position of the RSA is likely to become a routine ultrasound marker for chromosomal abnormalities in the second trimester of pregnancy.

Prenatal diagnosis of vascular rings.

OBJECTIVES: The purpose of this series was to identify vascular rings prenatally on fetal echocardiograms. METHODS: We reviewed the fetal echocardiograms and clinical histories of 9 patients with a diagnosis of vascular rings at our institution from 2004 to 2009. Eight patients had a prenatal diagnosis by fetal echocardiography. One other patient who had undergone fetal echocardiography had a diagnosis of a vascular ring and a cervical arch only postnatally. RESULTS: Among the 8 patients with a prenatal diagnosis (4 with a double aortic arch and 4 with a right aortic arch [RAA], an aberrant left subclavian artery, and a left ductus arteriosus [LDA]), the vascular ring was isolated in 4 and associated with other structural congenital heart disease in 4. In all 8 patients with a prenatal diagnosis, the vascular ring was identified by cephalad transducer sweeps from a 3-vessel view (3VV) with and without color Doppler imaging, which revealed vascular structures coursing around the trachea. Seven of these patients had postnatal confirmation of the abnormality (there was 1 pregnancy termination without autopsy). The only known vascular ring missed at fetal echocardiography but diagnosed after birth was that associated with a cervical RAA (which could not be visualized in cross-sectional sweeps) and an LDA evaluated only late in pregnancy. Only 3 of the 8 postnatally treated neonates had clinical symptoms of the vascular ring, and 5 underwent surgical division of the ring. CONCLUSIONS: Vascular rings can be largely identified before birth with cephalad sweeps from the 3VV with attention to the relationship of the aortic and ductal arches to the trachea on fetal echocardiograms.

Anomalies associated with aberrant right subclavian arteries. A case report

Anomalies in the aortic arch are a consequence of disorders in the development of the double primitive aortic arch system. We report a case of variation in the great vessels of the aortic arch, with an aberrant right subclavian artery being observed during a routine dissection. This variation was associated with a tight trachea in its distal end and a right lung devoid of the horizontal fissure, with a lack of tissue in the anterior segment of the superior lobe and in the lateral and medial segments of the middle lobe. The two common carotid arteries arose from a common trunk and the right recurrent laryngeal nerve was absent. On the basis of the literature, we review the incidence of the anatomical variation, its embryological explanation, and its clinical consequences (AU)

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Dependence of aortic arch morphogenesis on intracardiac blood flow in the left atrial ligated chick embryo.

Partial left atrial ligation before cardiac septation redistributes intracardiac blood flow and produces left ventricular hypoplasia in the chick. We hypothesized that redistributed intracardiac blood flow adversely alters aortic arch development. We ligated the left atrial appendage with a 10-0 nylon suture at stage 21 chick embryos, then reincubated up to stage 34. Sham embryos had a suture tied adjacent to the atrial wall, and normal controls were unoperated. We measured simultaneous atrioventricular (AV) and dorsal aortic (DAo) blood velocities from stage 24 embryos with an ultrasound pulsed-Doppler flow meter; and the left and right third and fourth aortic arch blood flow with a laser-Doppler flow meter. Ventricular and atrial cross-sectional areas were measured from sequential video fields for planimetry. Intracardiac flow patterns were imaged on video by injecting India ink into the vitelline vein. In separate embryos, radiopaque microfil was injected into the cardiovascular system for micro-CT scanning. We analyzed the morphologic characteristics of the heart at stage 34. Active AV and DAo stroke volume (mm(3)), right third and fourth aortic arch blood flow (mm(3)/s) were all decreased in ligated embryos (P < 0.05) when compared with normal and sham embryos. Ventricular end-diastolic volume versus normal and sham embryos decreased by 45% and 46%, respectively (P < 0.05). India ink injection revealed altered right aortic arch flow patterns in the ligated embryos compared with normal embryos. micro-CT imaging confirmed altered arch morphogenesis. Alterations in intracardiac blood flow disrupt both early cardiac morphogenesis and aortic arch selection.

Fetal cardiovascular morphology of interrupted aortic arch type B in rats.

Interrupted aortic arch type B associated with ventricular septal defect (n = 17) or atrioventricular septal defect (n = 2) was induced in 19 of 300 fetuses by maternal administration of bis-diamine on the 9th and 10th day of pregnancy. After rapid whole-body freezing on the 21st day, the fetuses were studied by means of serial cross-sectional photographs of the frozen thorax. In fetuses with interrupted aortic arch, the ascending aorta was small, and the ratio of its diameter to the diameter of the pulmonary trunk was 0.64 +/- 0.03 (mean +/- SEM) in contrast to 0.96 +/- 0.02 in the control. The aortic arch was interrupted distal to the left common carotid artery (type B of Cerolia and Patton) in all cases.

[Embryological aspects of anomalies of the aortic arch (author's transl)]. / Aortenbogenanomalien aus entwicklungsgeschichtlicher Sicht.

Various anomalies of the aortic arch have been examined angiographically and discussed in their embryological context. Theoretical concepts are based on Rathke's scheme of the aortic arch system. The importance of developmental aspects for the interpretation of anomalies of the aortic arch in angiography is emphasized.