Keywords
aortic arch - aneurysm - infant - cardiovascular imaging
Introduction
Aortic aneurysms are rare in infancy or childhood. Most of them are associated with
genetic aortic syndromes (connective tissue disorders or congenital bicuspid aortic
valve), infection, trauma, or complications following umbilical artery catheterization.[1]
[2]
[3] In terms of localization, they can develop in different parts of the aorta; the
most common are abdominal aneurysms, aneurysms of thoracoabdominal, or ascending aorta
occurring less frequently.[4]
[5] The treatment of these potentially life-threatening conditions can be complex and
challenging. We present a case of a congenital saccular aneurysm of the aortic arch
requiring surgical resection due to the risk of rupture or possible thrombus formation.
Case Presentation
During fetal sonographic screening of a 39-year-old primigravida, a saccular aneurysm
of the aortic arch of uncertain etiology was found. Based on this finding, a female
baby (38 weeks of gestation, weighing 3,290 g) was uncomplicated delivered by caesarean
section. Transthoracic echocardiography at birth confirmed the initial diagnosis. The aneurysm
(∼14 mm × 15 mm) was located in proximal aortic arch, in the area of the truncus brachiocephalicus.
No signs of other dilatations at the other segments of the thoracic aorta were observed.
The anatomy and the function of the heart were normal. The newborn was admitted to
the Department of Pediatric Cardiology and Intensive Care. The patient's clinical
status did not suggest any genetic aortic syndromes and the postnatal adaptation of
the baby had been uneventful. The patient was discharged home and monitored in the
department's outpatient clinic. However, indications suggesting growth of the aneurysm
were observed and the patient was readmitted for surgical treatment. A preoperative
computed tomography angiogram of the chest revealed a saccular aneurysm, localized
at the proximal part of the aortic arch and measuring 15 mm × 16 mm × 25 mm, compared
with a 9-mm ascending aorta and 6-mm transverse aortic arch. The truncus brachiocephalicus
was arising from the posterior portion of the aneurysm ([Fig. 1]). Due to the increasing size of aneurysm and related risk of rupture or possible
thrombus formation, a surgical resection of the aneurysm was performed in the patient
at age of 3 months.
Fig. 1 The preoperative computed tomography angiogram demonstrates a large saccular aneurysm
of the aortic arch with the truncus brachiocephalicus arising from the posterior part
of aneurysm.
After median sternotomy and resection of the thymus tissue, a pulsated protrusion
of the pericardium was found. The pericardium was opened carefully and the saccular
aneurysm in the proximal aortic arch was identified ([Fig. 2A]). Extracorporeal circulation was established with aortic and right atrium cannulation.
The left atrium was drained via the right upper pulmonary vein and the patient was
cooled down to 20°C. The transverse aortic arch and its branches were mobilized. Cardiac
arrest was achieved with antegrade cold blood cardioplegia. Perfusion flow was decreased,
and aortic cannula were placed in the truncus brachiocephalicus for selective brain
perfusion. The distal aortic arch and the aortic branches were clamped. The lumen
of aneurysm was carefully opened and the orifice of the truncus brachiocephalicus
inspected from inside ([Fig. 2B]). The irregular tissue of aneurysm was carefully resected, and the aorta was reconstructed
with a glutaraldehyde-treated autologous pericardial patch ([Fig. 2C]). The postoperative course was uneventful. The patient was extubated on postoperative
day 1 and discharged home on day 9. Histological examination revealed local degeneration
of the aortic wall with partial loss of elastic fibers and deposition of mucopolysaccharides
([Fig. 3A, B]).
Fig. 2 Intraoperative photos of the situs from the surgeon's view. (A) (*) indicates the large saccular aneurysm of the proximal aortic arch. (B) The aneurysm tissue was completely resected. (C) The aorta was reconstructed with pericardial patch. (#) indicates the pericardial
patch.
Fig. 3 Histopathology of aortic wall resected revealed partial loss of elastic fibers (A) Elastica van Gieson staining, ×20 magnification, (#) indicates elastic fibers, (*)
indicates a loss of fibers, and deposition of mucopolysaccharides. (B) Alcian blue staining, ×100 magnification, arrows indicate deposits of mucopolysaccharides
in the tunica media.
Medication with acetylsalicylic acid was initiated for 3 months postoperatively and
the baby was monitored for over 6 months at our outpatient clinic. At her most recent
follow-up, the echocardiogram revealed no local recurrence or any other dilatation
at the thoracic aorta ([Fig. 4]).
Fig. 4 Follow-up postoperative transthoracic echocardiographic image demonstrated the successful
result of the aneurysm resection and repair of the aorta. The arrow and additional
small image shows the area of pericardial patch in the reconstructed aorta with laminal
blood flow.
Discussion
Prenatal diagnosis has led to a significant improvement in the chances of survival
in children with congenital heart and vascular diseases. As evidenced by our case,
early diagnosis, particularly in the absence of symptoms, together with close interdisciplinary
cooperation, were essential factors for a successful clinical course. Diagnostic tools,
such as echocardiography and multidetector computed tomography angiography, are the
gold standard in accurately identifying such disorders.
Diagnostics and approach for these patients can be even more difficult in cases of
idiopathic disorders, as in our case. Usually, aneurysms' disorders are associated
with genetic connective tissues abnormalities, resulting in the degeneration of the
aortic wall and, subsequently, dilatation and aneurysm formation.[6] These are caused by degeneration of the median layer of the aorta and are usually
detected later in young adulthood. The laboratory evaluation of our patient revealed
no inflammatory markers indicating vasculitis. The absence of a positive family history,
any maternal risk factors, or a pathological course in pregnancy make the idiopathic
etiology in this case very likely.
Another challenging aspect in this case is the dearth of clear guidelines or recommendations
for the treatment of aortic aneurysm in infants. The guidelines for adult patients
with aortic aneurysm are unlikely to be applicable for pediatric or infant patients.
There is also a lack of relevant information in the clinical recommendations for pediatric
cardiology compared with the well-designed clinical practice guidelines for the management
of visceral artery aneurysms.[7] We opted for resection of the aneurysm as opposed to observation, based on the dimensions,
aortic arch localization, and progressive growth of aneurysm with the corresponding
risk of rupture or thrombus formation with the potential for thromboembolic events.
Despite recent advances and the rapid development of endovascular treatment technology
with reports of first successful embolization procedures for aortic aneurysms in newborns,[4] surgical treatment remains the standard of care in pediatric patients. The use of
autologous materials for aortic repair, well-established protective strategies in
neonatal surgery with extracorporeal circulation, and the possibility of histological
examination of the resected obtained during the operation are instrumental to the
success of the surgical approach. This is also evidenced by the uneventful postoperative
period and early follow-up results observed in our case.
Conclusion
In conclusion, our case presented one of the rare reports documented in the literature
requiring surgical resection of an idiopathic saccular aortic arch aneurysm in an
infant.
