Persistent left fifth aortic arch associated with tetralogy of Fallot

The aortic arch in tetralogy of Fallot: types of branching and clinical implications

INTRODUCTION

Tetralogy of Fallot is the most common form of cyanotic CHD, with an incidence of 421 cases per million live births, constituting around 10% of CHD. Variations in aortic arch anatomy associated with tetralogy of Fallot, other than the incidence of right aortic arch (13-34%), are not frequently reported. A comprehensive analysis of a large number of tetralogy of Fallot cases is required to arrive at a compendious description of aortic arch anatomy.

MATERIALS AND METHODS

All patients with a diagnosis of tetralogy of Fallot who had CT or MRI either pre or post procedures between 1 January 2010 and 31 December 2019 at our hospital were included in the study. Using radiology consultants' reports and analysis of individual images, we identified the various morphological patterns of aortic arches prevalent in these patients.

RESULT

Out of 2684 patients who met the inclusion criteria, 1983 patients had left aortic arch (73.9%), 688 patients had right aortic arch (25.7%), four patients had cervical aortic arch (0.15%), eight patients had double aortic arch (0.3%), one patient had an aorto-pulmonary window (0.04%), and none of the patients had interrupted aortic arch. Sub-classification and clinical implications of the arch variations are described.

CONCLUSION

Up to 10% of tetralogy of Fallot patients may have significant anatomical variations of aortic arch that would necessitate changes or additional steps in their surgical or interventional procedures.

Persistent fifth aortic arch: the "great pretender" in clinical practice

Persistence of the embryonic "fifth aortic arch" in postnatal life is a rare, enigmatic - and at times controversial - condition, with variable anatomical forms and physiological consequences. First described in humans over 40 years ago by Van Praagh, the condition was labelled the "great pretender" by Gerlis 25 years later, because of its apparent propensity to mimic anatomically similar structures. Despite many subsequent case reports citing the condition, the true developmental origin of these structures remains unresolved, and has been the subject of debate among embryologists for more than a century. A persistent fifth aortic arch has been defined as an extrapericardial structure, arising from the ascending aorta opposite or proximal to the brachiocephalic artery, and terminating in the dorsal aorta or pulmonary arteries via a persistently patent arterial duct. This description may therefore encompass various anatomical forms, such as a unilateral double-lumen aortic arch, an unrestrictive aortopulmonary shunt, or a critical vascular channel for either the systemic or pulmonary circulation. The physiological properties of these vessels, such as their response to prostaglandins, may also be unpredictable. In this article, we demonstrate a number of cases that fulfil the contemporary definition of "persistent fifth aortic arch" while acknowledging the embryological controversies associated with this term. We also outline the key diagnostic features, particularly with respect to the use of new cross-sectional imaging techniques.

Multiple variations of the cerebral arteries associated with tetralogy of Fallot: a case report

Tetralogy of Fallot (TOF) can be associated with vascular malformations or variations, especially of the aortic arch or supracardiac major venous systems. We report its association with an extremely rare combination of three such variations of the cerebral arteries-a right persistent hypoglossal artery, an extremely rare left carotid-right anterior cerebral artery (ACA) anastomosis, and a left accessory middle cerebral artery arising from the A1-A2 junction of the left ACA-which were diagnosed by magnetic resonance angiography in a 9-year-old girl during evaluation of multiple acute cerebral infarctions.

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.

Persistent fifth aortic arch with interrupted aortic arch

Persistent fifth aortic arch (PFAA) is one of the rarest congenital anomalies. We report a seven-month-old male with PFAA with upper arch interruption and lower arch coarctation diagnosed by echocardiogram and multidetector computed tomography.

Coarctation of persistent 5th aortic arch: first report of catheter-based intervention

Persistent 5th aortic arch, originally called double-lumen aortic arch, is a rarely reported cardiac developmental anomaly that results in systemic-to-systemic or systemic-to-pulmonary shunting. When this malformation occurs, other intracardiac defects are almost always present. We report the case of a 7-month-old girl who presented with a heart murmur; she was found to have an interrupted 4th aortic arch and coarctation of a persistent 5th aortic arch, with no other defects. To our knowledge, this is the 3rd report of a pediatric patient with this condition in isolation, and the first report of its diagnosis and treatment by means of cardiac catheterization and balloon angioplasty.

Distal aortic arch aneurysm associated with persistent fifth aortic arch

Persistent fifth aortic arch (PFAA) associated with interruption of the fourth aortic arch is a rare malformation, usually requiring surgical intervention in childhood. A 51-year-old woman developed a distal aortic arch aneurysm associated with PFAA after patch aortoplasty for coarctation of the aorta at the age of 18. To our knowledge, this is the first reported case of a distal aortic arch aneurysm associated with PFAA. Residual tissues of the ductus and PFAA, which is not a definitive aortic arch, and the implanted synthetic patch may have been related to the development of the aneurysm. Graft interposition between the proximal border of PFAA and the descending aorta was performed because severe adhesions impeded the application of the fourth aortic arch as a proximal anastomotic site of the graft. Accurate diagnosis and sufficient understanding of PFAA allow an appropriate surgical treatment in childhood with a good result over the long term.

A rare association with patent ductus arteriosus

Persistent fifth aortic arch (PFAA), also known as congenital double-lumen aortic arch, is a rare developmental anomaly of the aortic arch. A 5-month-old baby who presented with congestive cardiac failure was diagnosed to have a large patent ductus arteriosus with PFAA. Although this arch anomaly had no hemodynamic relevance in this case, preoperative diagnosis prevented surprises “on table.”

Multi-detector computed tomography demonstration of double-lumen aortic arch--persistent fifth arch--as an isolated anomaly in an adult

Persistent fifth - double-lumen - aortic arch is a rarely seen entity, which is usually associated with other cardiac anomalies; it has been previously reported only in children. We report a new case of double-lumen aortic arch with a systemic-to-systemic connection diagnosed incidentally during cardiac multi-detector computer tomography evaluation of coronary artery bypass grafts in an adult.

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.

Persistent fifth aortic arch associated with coarctation of aorta: a case report

A 20-year-old man with persistent fifth aortic arch associated with coarctation of the aorta underwent catheterization and stenting of coarctation of the aorta.

Cardiovascular development and survival during gestation in the Ts65Dn mouse model for Down syndrome

The Ts65Dn mouse model for Down syndrome (DS) exhibits many phenotypes seen in human DS. Previous research has revealed a reduced rate of transmission of the T65Dn marker chromosome in neonates. To analyze potential fetal loss, litters from trisomic females at 10.5dpc through 14.5dpc were genotyped. No significant differences from the expected Mendelian ratio were found in transmission of T65Dn at any stage. Cardiovascular defects found in trisomic neonates are associated with formation of pharyngeal arch arteries. Vessel tracing was used to identify anomalies in 10.5dpc, 11.5dpc, and 13.5dpc embryos. Comparison of trisomic versus euploid embryos injected with India ink revealed delay and abnormality in cardiovascular development in trisomic embryos at each stage. Through the analysis of transmission rate and cardiovascular development in embryonic mice, we learn more about prenatal mortality and the origins of cardiac abnormality in the Ts65Dn mice to assist in understanding cardiovascular malformation associated with DS.

Aortic coarctation with persistent fifth left aortic arch

A neonate with severe aortic coarctation showed a double lumen transverse aorta (persistent fifth aortic arch) with both channels joining at the isthmus where the obstruction was confirmed by echocardiography and cardiac catheterization. Surgical repair was performed with a pantaloon-shaped patch. Persistent fifth aortic arch does not result in a vascular ring and, per se, is not hemodynamically significant unless associated with other cardiac malformations.

Surgical Treatment of Persistent Fifth Aortic Arch Associated with Interrupted Aortic Arch

This study describes two cases of the rare congenital anomaly, persistent fifth aortic arch. Both cases involve boys (1 at 9 years of age and another at 7 months of age). To detect persistent fifth aortic arch with interrupted aortic arch, the following methods were used: echocardiogram, angiocardiography, and magnetic resonance imaging. In both cases the blood pressure between the upper and lower limbs differed. To relieve the obstruction of blood flow, each case was surgically repaired using patching or conduit interposition. Postoperative courses were uneventful. Two-year to 5-year follow-up examinations were positive showing that the anastomosis was unobstructed and the velocity of blood flow to the descending aorta was normal.

Echocardiographic diagnosis of persistent fifth aortic arch

We describe echocardiography and computerized tomographic imaging findings in the two subtypes of fifth aortic arch in infants. In the first form, the fifth aortic arch creates a systemic to systemic connection extending from the ascending to the descending aorta. When this form appears in isolation, it does not cause hemodynamic disturbance, although associated cardiac lesions, such as aortic coarctation or interruption and patent ductus arteriosus, may influence the clinical presentation. In the second form the fifth aortic arch connects the systemic and pulmonary circulations from persistent connections between the embryological fifth and sixth arches, which may cause significant hemodynamic disturbance from left to right shunting. Although this form has been associated with a wide array of congenital cardiac lesions, this is the first description of 5th aortic arch in association with atrioventricular septal defect and double outlet right ventricle.

Contrast-enhanced magnetic resonance angiography of persistent fifth aortic arch in children

BACKGROUND

Cine angiography and echocardiography have been utilized to diagnose congenital aortic arch anomalies. However, the visualization of great vessels by echocardiography is limited, while cine angiography requires cardiac catheterization with ionizing radiation. Contrast-enhanced magnetic resonance angiography (MRA) is a noninvasive modality suitable for visualization of congenital aortic arch anomalies.

OBJECTIVE

To evaluate the utility of contrast-enhanced MRA in the diagnosis of persistent fifth aortic arch, a rare congenital aortic arch anomaly, and to compare the diagnostic accuracy of MRA with that of echocardiography and cine angiography.

MATERIALS AND METHODS

In four pediatric patients, contrast-enhanced MRA studies were performed for diagnosing persistent fifth aortic arch. The findings of MRA were compared with echocardiographic findings and confirmed by cine angiography and operation.

RESULTS

Transthoracic surface echocardiography noted an aberrant vessel arising from the ascending aorta in two of four patients; the etiology of this vessel was uncertain. In the other two patients a diagnosis of coarctation was made. Of the four patients, only one was diagnosed with interruption of the aortic arch. Contrast-enhanced MRA clarified uncertain echocardiographic findings, enabling the correct diagnosis of persistent fifth aortic arch with fourth aortic arch interruption in all four patients.

CONCLUSION

Contrast-enhanced MRA is a safe, accurate, and fast imaging technique for the evaluation of persistent fifth aortic arch and may obviate the need for conventional cine angiography. Cardiac catheterization may be reserved for some types of complicated congenital heart disease and for obtaining hemodynamic information.

Persistent Fifth Aortic Arch Associated with 22q11.2 Deletion Syndrome

BACKGROUND

Chromosome 22q11.2 deletion is frequently associated with conotruncal malformations and aortic arch anomalies. This study investigated the association of chromosome 22q11.2 deletion with clinical manifestations in four pediatric patients with persistent fifth aortic arch.

METHODS

Four patients with persistent fifth aortic arch treated between July 1997 and June 2004 were included in this retrospective study. There were two girls and two boys, aged 2 days to 11.3 years, with persistent fifth aortic arch and cardiac conotruncal malformations. Chart recordings, plain chest films, two-dimensional and Doppler echocardiograms, cardiac catheterization with angiograms, surgical findings, and cytogenetic study were analyzed.

RESULTS

Clinically, all four patients had the cardinal phenotypic features of 22q11.2 deletion syndrome, including cardiovascular malformations (conotruncal malformations and aortic arch anomalies), abnormal facies, thymic hypoplasia, canopy anomaly of the palate (high-arched palate, rather than cleft palate), and hypocalcemia (or hypoparathyroidism). All four patients were confirmed to have chromosome 22q11.2 deletion.

CONCLUSION

Congenital conotruncal malformations, including tetralogy of Fallot with pulmonary atresia or stenosis, and aortic arch anomalies including a persistent fifth aortic arch or a right aortic arch, should lead to suspicion of chromosome 22q11.2 deletion when manifested together with any one of the other four cardinal phenotypic features.

Truncus arteriosus with coarctation of persistent fifth aortic arch

Truncus arteriosus is a rare form of congenital heart defect. Among cases, 10% to 20% are associated with arch anomalies, such as interruption, coarctation, or patent ductus arteriosus. We treated a rare case of combined truncus with complex arch anomaly. The patient was a 2-month-old girl weighing 3.8 kg. Echocardiogram and computed tomogram showed interrupted aortic arch, truncus arteriosus, persistent fifth aortic arch, and its coarctation. One-stage total correction was performed under cardiopulmonary bypass without circulatory arrest. The operation consisted of a Rastelli procedure with a 12-mm valved conduit, coarctoplasty, and intraventricular baffling. The patient recovered well without complications.

Persistent fifth aortic arch: an ignored and underestimated disease

We report two unique cases of persistent fifth aortic arch with a systemic-to-pulmonary connection. All previously reported cases with such a connection in the literature have either been cases of pulmonary atresia or an aortic arch anomaly, and the existence of a fifth aortic arch was a benefit to the underlying great vessel anomaly. However, our two cases did not have this associated great vessel anomaly, and the fifth arch resulted in a large left-to-right shunt with severe pulmonary hypertension and heart failure. The first case was misdiagnosed preoperatively; an accurate diagnosis was made after cardiac surgery. Because of its rarity and complexity, a persistent fifth aortic arch is often ignored and misdiagnosed.