Right aortic arch with aberrant left subclavian artery—prenatal diagnosis and evaluation of postnatal outcomes: Report of three cases

Objective To explore the value of three-vessel and trachea(3VT) view plus aortic arch coronal section in ultrasonic diagnosis and classification of fetal right aortic arch(RAA). Methods Echocardiography data and follow-up results of 44 fetuses with RAA were retrospectively analyzed. Sonographic features on 3VT view and aortic arch coronal section were summarized. Results Among 44 fetuses with RAA, 27 cases(61.36%) were RAA with aberrant left subclavian artery(ALSA) and the left ductus arteriosus(LDA) connecting the ALSA and U-shaped vascular ring was formed; 17 cases(38.64%) were mirror right aortic arch(MRAA). Among 17 cases with MRAA, 3 cases were with LDA connecting the descending aorta(DAO) and U-shaped vascular ring was formed; 1 case was with LDA connecting the left innominate artery(LINA), 8 cases were with absent ductus arteriosus(ADA), 5 case were with right ductus arteriosus(RDA), no vascular ring was formed. Parts of MRAA were combined with other complex intracardiac abnormalities. RAA-ALSA-LDA were rarely combined with intracardiac abnormalities. Conclusions 3VT view is simple and intuitive for diagnosing RAA. Aortic arch coronal section has great clinical value in determining the concrete type of RAA. Key words: Echocardiography; Fetus; Aortic disease; Three-vessel and trachea view; Aortic arch coronal section

Purpose Congenital right aortic arch (RAA) and double aortic arch (DAA) were difficult to be diagnosed by traditional fetal echography. However, these two diseases have distinct clinical therapies and long-term outcomes which makes the differential diagnosis of great importance. While fetal screening by traditional fetal echography provides limited information about the branches of the aortic arch. This study aimed to discover and evaluate a novel combination of different echocardiography views in the diagnosis and differentiation of RAA and DAA. Methods From January 2014 to December 2022, a total of 414,686 pregnant women underwent routine ultrasound examinations of the fetus during the second trimester. The scan of the fetal heart included a fetal four-chamber view, The left ventricular outflow tract (LVOT) view, a right ventricular outflow tract (RVOT) view, a three-vessel (3 V) view, and three vessels and trachea (3VT) view. Then the cases diagnosed as RAA or DAA by initial ultrasound screening from two hospitals were divided into the RAA group and the DAA group. Then enter the prenatal diagnosis consultation. All the pregnant women were offered invasive prenatal diagnosis. Genetic tests were fully discussed and decided after genetic counseling. Further ultrasound examination by two more experienced sonographers, in addition to the fetal echocardiogram views, includes further multi-angle scanning of the aortic arch branches with color Doppler flow imaging (CDFI) or high definition flow imaging (HDFI) for further diagnosis, and the reasons for misdiagnosis were analyzed and summarized. Results A total of 332 cases were diagnosed with RAA or DAA by initial ultrasound, including RAA group 244 cases and DAA group 88 cases. In the RAA group, the mirror RAA (MRAA) could not be completely diagnosed by 3VT view alone in traditional echocardiography, with accuracy and sensitivity of 88.9% and 72.6%, respectively. In the DAA group, 36 cases were misdiagnosed only by 3VT view alone in traditional echocardiography, with the accuracy and specificity of 88.9% and 86.8%, respectively. However, the accuracy for MRAA or DAA could reach 100% when combined with 3VT and multi-angle scanning of the aortic arch branches. The abnormal detection rate of genetic tests was 10.5% (20/190), excluding the cases who refused the invasive prenatal diagnosis. Conclusion Combining 3VT and multi-angle scanning of the aortic arch branches With CDFI or HDFI could effectively distinguish RAA variants from DAA. The invasive prenatal diagnosis should be recommended for patients with RAA or DAA, and the accurate prenatal diagnosis was highly valuable in providing appropriate perinatal counseling and prognostic evaluation.

Objective To investigate the value of prenatal echocardiographic diagnosis of anomalies of the right aortic arch(RAA) and its branch type, and provide rapid diagnostic methods. Methods A retrospective analysis of 55 cases of RAA of prenatal ultrasound diagnosis results, and their imaging characteristics were summarized. Results There were 55 cases of anomalies of the RAA, included 42 cases of RAA with aberrant left subclavian artery(RAA-ALSA) and 13 cases of RAA with mirror image branching pattern(RAA-MB), 1 case of double aortic arch(DAA) was misdiagnosed as RAA. The prenatal echocardiographic characteristics of RAA-ALSA: in three-vessel-aortic arch view, the first branch of the aortic arch was the left carotid artery, which ran in front of the trachea, and ALSA ran behind the trachea and esophagus. The prenatal echocardiographic characteristics of RAA-MB: the first branch of the aortic arch was the brachiocephalic trunk, which ran in front of the trachea and was divided to the left carotid artery and the left subclavian artery. Conclusions Prenatal ultrasound can qunickly and accurately diagnose anomalies of the right aortic arch and its branch type according to the direction, thickness and secondary branches of the first branch of the aortic arch. The location of arterial duct is helpful to judge the formation of vascular ring. Key words: Ultrasonography, prenatal; Right aortic arch; Vascular ring

GP25 Comparison of associations and outcomes of prenatally and postnatally diagnosed right aortic arch: south wales’ experience

Objective To investigate the ultrasonic imaging features of and differential diagnosis methods for the right aortic arch, to analyze the causes of missed diagnosis and misdiagnosis, and to further improve the accuracy of prenatal ultrasound diagnosis. Methods Cardiac screening examination of the fetus was carried out with views of gray-scale and color Doppler or power Doppler imaging (PDI). When the three-vessel tracheal (3VT) view found that the aortic arch was located in the right of the trachea, the coronary views of the trachea and its branches were obtained to further clarify the relationship among the aortic arch, arterial ductus, and trachea. The sonographic features of 31 cases of fetal right aortic arch were summarized, and the reasons for misdiagnosis were analyzed. Results Of the 31 cases of fetal right aortic arch diagnosed by prenatal ultrasound, 20 were alive, 15 were induced, and 6 were lost. As for the results of echocardiography for postpartum children, operation or autopsy were obtained in 31 cases, of which 6 had misdiagnosis or missed diagnosis by prenatal ultrasonography. The coronal views of the trachea and its branches were not obtained in two cases of fetal left aortic arch, and they were misdiagnosed as right aortic arch because the transversely sectioned bronchus were mistaken as the transversely sectioned trachea in the 3VT view. In two cases of right aortic arch with aberrant left subclavian artery, the left common carotid artery was misdiagnosed as a stunted left arch, which resulted in a misdiagnosis as a double aortic arch of the advantage type. In two cases of right aortic arch combined with cardiac defects, right aortic arch was missed in prenatal ultrasound diagnosis. Of 20 children who were followed, 13 were diagnosed with isolated right aortic arch, 2 with combined persistent left superior cavity, 1 with combined 2-3 lumbar vertebral body fusion, and 2 with combined right aortic arch inner or outer non-complex structure abnormality. Follow-up was conducted to the maximum age up to 3 years and 6 months, and 18 of these cases were in good condition and showed no symptoms of respiratory tract compression. One case suffered from complicated intracardiac malformation combined with IDD type congenitally corrected transposition of the great arteries. The child is currently in good condition 11 months after the delivery. One case suffered from combined esophageal atresia and died 14 days after delivery. Chromosome karyotype determination was performed in 6 cases, of whom 5 were normal and 1 was confirmed to have 18-trisomy with severe intracardiac multiple malformation. Conclusions The 3VT view is the most important view for diagnosis of right aortic arch of fetus. The accuracy of prenatal ultrasound diagnosis can be improved through the combination of the 3VT view and the coronal view of the trachea and its branches. Simple right aortic arch offers a good prognosis, and the prognosis of right aortic arch with severe ectopic and extracardial malformations depends on the severity of the combined malformation. Key words: Fetal right aortic arch; Ultrasonography, prenatal; Pregnancy outcome

Objective To investigate the clinical value of ultrasound diagnosis of fetal right aortic arch (RAA).Methods From March 5,2009 to September 2,2012,18 600 pregnant women in three hospitals in Foshan City,Guangdong Province,were divided as RAA high-risk group (n=5000) and low-risk group (n =13 600).During 18 to 42 gestational weeks,detailed ultrasound examinations of fetal aortic arch were done.All babies received echocardiography,CT or MRI within 15 months after birth to observe the cardiovascular condition,and aborted fetus was autopsied.RAA type,complicated structural abnormality and pregnancy outcomes between the two groups were compared with Chi-square test.Results Fifteen fetal RAA were diagnosed prenatally in the low-risk group,and the detection rate was 0.11％ (15/13 600),which was lower than that in the high-risk group (0.60％,30/5000)(x2=98.20,P＜0.01).The correct rate of prenatal ultrasound diagnosis of RAA was 96％ (43/45),while the other two cases were diagnosed as RAA with aberrant left subclavian artery and confirmed to be double aortic arch and RAA with mirror image after birth.In the high-risk group,the incidence of RAA with mirror image,cardiac and extra-cardiac malformation was 73％(22/30),67％(20/30) and 27％(8/30),respectively,which were higher than those in the low-risk group(0/15,1/15 and 0/15)(x2 =30.000,25.200 and 28.000,P＜0.01 respectively).The incidence of RAA with aberrant left subclavian artery and the 15-month survival rate of RAA infants in the high risk group was lower than those in the low-risk group [20％ (6/30) vs 12/15,40％ (12/30) vs 15/15] (x2=7.700 and 15.610,P＜0.05,respectively).Conclusions The incidence of fetal RAA is higher in the high-risk pregnant women than in the low-risk pregnant women,and babies often complicated with other malformations with poor prognosis. Key words: Ultrasonography, prenatal; Aorta, thoracic; Congenital abnormalities; Vascular malformations ; Pregnancy

Repair of Kommerell's Diverticulum and Aberrant Subclavian Arteries: Classification of the Five Groups in Declining Frequency and Their Operative Approaches

Objective By comparing the results of prenatal diagnosis of vascular rings by ultrasound and MRI, chromosome screening and postnatal follow-ups, to explore the clinical significance of prenatal diagnostic technology for the diagnosis of vascular rings and prognostic assessment. Methods Ninety-five fetuses that were diagnosed by fetal echocardiography were followed up regularly, of which 72 cases had chromosome screening, 31 cases had MRI examination. These results were compared with the postnatal follow-up outcome. Results Ninety-five cases of vascular rings included 85 cases of right aortic arch(RAA) and left ductus arteriosus(LDA), 4 cases of pulmonary artery sling(LPAS), 4 cases of double aortic arch(DAA), 1 case of RAA and double ductus arteriosus(DDA), 1 case of left aortic arch(LAA) and aberrant right subclavian artery(ARSA). Sixty-six cases of isolated vascular rings and 29 cases of complex vascular rings(combined with other cardiovascular abnormalities) were detecded. Fifty-four cases were born(2 infants died), 8 cases were ongoing pregnancy, 6 cases were lost to follow-up, 27 cases were aborted. Prenatal ultrasound and MRI examination indicated 6 cases of trachea compression. However, only 3 infants showed clinical symptoms due to trachea compression from born 5 cases. Conclusions Isolated vascular ring is the most common format and its diagnosis and type can be determined by prenatal ultrasound. Dynamic follow-up using ultrasound in pregnancy combined with MRI is helpful to assess the compression degree of trachea induced by vascular ring and prognosis. Key words: Ultrasonography, prenatal; Magnetic resonance imaging; Fetal heart; Vascular ring

The prenatal detection of a right-sided aortic arch achieved mainly by targeted visualization of the threevessel and three vessels and trachea (3VT) view, with or without color Doppler, has been discussed recently in this journal1–4. Two typical forms of a right aortic arch can be distinguished5,6. In one condition a vascular ring is found around the trachea, the so-called U-sign prenatally (Figure 1)2,3. The trachea and esophagus are entrapped between the right aortic arch and the left ductus arteriosus and this abnormality is often an isolated incidental finding prenatally2. In the other condition, both the aorta and ductus arteriosus lie to the right of the trachea without a vascular ring. This condition is very commonly associated with cardiac anomalies5. The branching pattern of the great vessels arising from the aortic arch in both conditions is of major interest in pediatric cardiology5,6. The right aortic arch without a vascular ring usually exhibits mirror image branching of the arteries with the left innominate (brachiocephalic) artery arising first followed by the right common carotid and right subclavian artery6. By contrast, the right aortic arch with vascular ring very often has an association with an aberrant left subclavian artery. The left common carotid arises first from the aortic arch, followed by the right common carotid, right subclavian artery, and finally a retroesophageal vessel segment from which the left subclavian artery arises and the ductus arteriosus connects. The retroesophageal (and retrotracheal) vessel segment is known as the diverticulum of Kommerell. In other words, the left subclavian artery is connected ventrally to the ductus arteriosus arising from the left pulmonary artery, and dorsally through the Kommerell’s diverticulum to the descending aorta. In postnatal life, after closure of the ductus arteriosus, blood enters the left subclavian artery via the descending aorta and Kommerell’s diverticulum4. Prenatal assessment of a right-sided aortic arch and its branching pattern requires scanning in such planes as a transverse 3VT view (Figure 1), oblique cephalad Left

Vascular ring is a rare congenital anomaly in which the abnormal origin of the aorta or its branches and pulmonary arteries leads to encircling and compression of the trachea and esophagus. A right aortic arch (RAA) with an aberrant left subclavian artery is one of the most common forms of vascular ring. Here, we report a case of a prenatally diagnosed vascular ring resulting from an RAA with an aberrant left subclavian artery. When the infant was 7 months of age, the development of noisy breathing prompted further evaluation with cardiac magnetic resonance imaging that showed an atretic left subclavian artery associated with collateral retrograde flow from the left vertebral artery to the distal portion of the subclavian artery. Our findings indicate that an untreated RAA with an aberrant left subclavian artery may be associated with an increased risk of developing subclavian artery steal syndrome.

Outcomes of Surgical Repair of Vascular Rings and Slings in Children: A Word for the Asymptomatic

To analyze the characteristics and clinical implications of right aortic arch (RAA) detected in fetal life. Retrospective study of all cases of RAA diagnosed prenatally in high-risk patients who underwent fetal echocardiography between 2000 and 2007. There were 48 RAA; 18 had vascular ring (Group 1), including 15 RAA with aberrant left subclavian artery and 3 double aortic arch, and 30 had not vascular ring (Group 2), all RAA with mirror-image branching. The prenatal diagnosis was confirmed in 94%. In Group 1 most fetuses had normal heart (89%), and none had 22q11 deletion. There were 16 live births and all infants but one are asymptomatic (mean follow-up of 31 months). In Group 2 almost all fetuses had congenital heart defects (CHDs) (97%), and five were chromosomally abnormal (17%), including four 22q11 deleted. The 1-year survival rate was 69%, which was significantly higher in Group 1 (89% vs 57%, p < 0.05). RAA can be accurately diagnosed by fetal echocardiography. The outlook for these patients largely depends on the presence of associated defects, mainly CHDs, and their severity. If isolated, aortic arch anomalies are asymptomatic vascular variants in most cases. This information is important to assist parental counseling in pregnancy.

This study aimed to elucidate the diagnostic process, the associated anomalies and the perinatal outcomes of right aortic arch (RAA) in a group of low-risk patients. The obstetric imaging database and digital patient files were reviewed between January 2015 and June 2016. There were 12 RAA cases detected prenatally. Seven foetuses had an aberrant left subclavian artery and one foetus had mirror image branching. The prevalence of RAA was 1.8 in 1000. Invasive prenatal diagnosis was offered to patients and seven tests were performed. There was one associated cardiac anomaly (8.3%) and one extra-cardiac anomaly (8.3%) in the same foetus which cordocentesis revealed trisomy 21. There were also two 22q11.2 microdeletion cases with isolated RAA with aberrant left subclavian arteries. All patients have given live births except one patient has chosen a termination of pregnancy for 22q11.2 microdeletion. The median follow-up time of the newborns was 21 months. None of the babies required surgery for RAA during follow-up. All the babies are alive, except for the one with trisomy 21, who dead at 5 months due to the surgical complications of an oesophageal atresia operation. Patients with an RAA foetus should be offered for foetal karyotyping and analysis for 22q11.2 microdeletion. When isolated, RAA has usually a good prognosis and rarely requires cardiac surgery.Impact StatementWhat is already known on this subject? Prenatal diagnosis of RAA should prompt a detailed cardiac and extra-cardiac ultrasound examination. When isolated, RAA is associated with 22q11 deletion and aneuploidies in 4.6% and 5.1%, of cases respectively.What the results of this study add? Our study showed that 28.5% of isolated RAA cases are associated with 22q11.2 microdeletion. Cardiac surgery is rarely required when RAA is an isolated anomaly.What the implications are of these findings for clinical practice and/or further research? Invasive prenatal testing for karyotypes and 22q11.2 microdeletion should be offered to patients with RAA, even in the case of an isolated one. Further larger studies are needed to confirm this finding.

Prenatal Diagnosis and Outcome of Right Aortic Arch without Significant Intracardiac Anomaly

Background Isolated right aortic arch (RAA) is felt to be a rare finding, present in around 0.1%. The 3 vessel and tracheal view has been part of the fetal medicine departmental screening since 1998 and has now been incorporated into the national screening guidelines. The objective is to define the prenatal associations and postnatal outcomes of fetuses diagnosed with a RAA in utero. Methods Retrospective analysis of fetuses diagnosed with an isolated RAA diagnosed at the Harris Birthright Centre for Fetal Medicine between 2000 and 2014. Prenatal and postnatal findings were ascertained from clinical records. Diagnosis of RAA was made in the transverse three-vessel/tracheal view where the aortic arch was demonstrated passing in front of the trachea.(Figure 1) Prenatal data were combined with outcomes obtained from medical records and telephone interviews with patients. Results 100 cases of isolated right aortic arch were identified in fetal life at a median gestation of 21weeks (range:11–36). The nuchal translucency (NT) was elevated in 10/64 (16%) where the measurement was known and an extracardiac abnormality detected in 23/100 cases of whom 2 had a raised NT. Genetic abnormalities were confirmed in 13/58 (21%) tested cases comprising: 22q11.2 microdeletion (n = 5), trisomy 21 (n = 2), combined 22q11 microdeletion with mosaicism of 45XO (n = 1), unbalanced translocation (n = 1), balanced translocation (n = 1), duplication of chromosome 16p13 with a recessive disorder of lymphogenesis (n = 1) and other syndromes (n = 3). Of those with abnormal genetics 4/13 had no other abnormal fetal sonographic markers. An aberrant left subclavian artery (ALSCA) was identified in 39/98 (40%), the arterial duct was left sided in 67/75 (89%). In the postnatal period, 3 cases were diagnosed with a double aortic arch. Spontaneous intrauterine death occurred in 6 cases and termination of pregnancy in 9 cases. There were 80 live births and one neonatal death. Five children presented with symptoms of airway obstruction at a median age of 2.9 years (range 1–8). Pulsatile airway compression was identified in all and surgical division of the vascular ring was performed at median age: 2.9years (range: 1–8). Within the past two years, three asymptomatic infants (with RAA, ALSCA, left arterial duct) have been shown by bronchoscopy and cross-sectional imaging to have significant airways compression. Thus, we are currently considering whether all infants with RAA, ALSCA and left duct merit investigation irrespective of symptoms. Conclusions Significant genetic abnormalities were identified of which some had no other abnormal fetal sonographic findings. Many patients were discharged after their first postnatal review, but despite this 8 children have required surgical relief of a vascular ring as a result of pulsatile compression of the trachea. Lack of symptoms does not exclude significant airways compression and the true incidence of airway compromise may be underestimated.