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A
17-month-old patient with transposition of the great arteries and ventricular
septal defects presented without pulmonary over-circulation and significant
aortopulmonary collaterals before surgery, and subsequently presented with
hemoptysis and pulmonary congestion after arterial switch operation.
Postoperative angiography revealed one aberrant right bronchial artery and two
aortopulmonary collaterals arising from both subclavian arteries. Percutaneous
embolization of the abnormal vessels caused dramatical improvement in patient’s
conditions and rapid weaning from mechanical ventilation support, and he was
discharged without any complications. This highlights the importance of cardiac
catheterization to detect collateral vessels as a cause for pulmonary
over-circulation and hemoptysis even though they seemed trivial and irrlevent
before surgery Embolization is an effective and safe method of treatment for
hemoptysis in children.
Keywords: Arterial switch operation, Hemoptysis,
Bronchial artery, Aortopulmonary Collateral sembolization
CASE PRESENTATION
A 17-month-old boy weighing 9kg,was admitted to
our hospital with mild dyspnea and cyanosis. Transthoracic echocardiography
revealed D-transposition of the great arteries (d-TGA) with large
perimembranous and muscular ventricular septal defect(VSD)and pulmonary
hypertension (PH). A frontal chest X-ray showed cardiomegaly with cardiac
contours appearing like an egg on string and pulmonary congestion (Figure 1A).
Diagnostic cardiac catheterization and
angiography (Figure1B, 1C) was
performed to confirm the common coronary pattern and multiple VSDs. Small
aortopulmonary collateral arteries were found to arise from branches of the
aortic arch, but we took it for granted that these vessels were too trivial to
affect hemodynamics. The pulmonary vascular resistance index was 2Wu.U.m² under
21% inspired oxygen, which revealed he still had the chance to undergo primary
repair.
At the ninth day of admission, he underwent
arterial switch operation (ASO) with VSDs closure. At surgery, there was
increased pulmonary venous return but no other unusual findings were
encountered. He was transferred to the intensive care unit and was cared for by
skilled medical staff. Suitable postoperative care, including the use of
catecholamine and mechanical ventilation, was provided. However, the recovery
of hemodynamic status was slow, with signs of pulmonary congestion and
cardiomegaly on chest X-ray. Even worse he suffered from hemoptysis approximately
20 mL of fresh blood 1 day after surgery, and recurrent hemoptysis gradually
worsened over the next 2 days despite the use of laser coagulation and
hemostatic drugs. Postsurgical echocardiographic evaluation failed to show
residual defects and there was no evidence of neo-aortic stenosis or
insufficiency, but unique supra-aortic anomalous color doppler signals to the
pulmonary circulation was identified, suggesting aortopulmonary collaterals.
Two weeks after surgical repair, the baby
was restudied by cardiac catheterization. Right catheterization showed a mean
pulmonary arterial pressure of 45 mmHg, and pulmonary angiography ruled out the
presence of any pulmonary arteriovenous malformation. On selective aortic
arteriography (Figure 2), one enlarged aberrant right bronchial artery which
followed the normal branching pattern of the airways with an area of
hypervascularity and neovascularity was identified from the right subclavian
artery, two aortopulmonary collateral arteries with segmental parenchymal
distribution arised from both subclavian arteries. There were no dilated
bronchial arteries originating from the T5-T6 segments. We suspected that these
abnormal vessels were responsible for the hemoptysis and were reasonable to be
occluded to improve the condition. All of these abnormal vessels were
sequentially embolized by 500-700um Embosphere microsphere (Merit Medical, USA)
and microcoils (Tornado; Cook Medical, USA), using coaxial microcatheter
technique. The closure of these anomalous vessels was associated with
significant improvement of the clinical status of the baby, permitting
successful extubation 7 days after embolization and decrease of the inotropic
support. He was discharged with an oxygen saturation of 93% and no
complications happened. There was no recurrent hemoptysis after a follow-up of
12 months.
DISCUSSION
The most common complications after an ASO
are the supravalvular pulmonary stenosis, neoaortic valve dysfunction and
myocardial ischemia related to coronary artery translocation [1]. However,
about half of patients with TGA undergoing ASO present with anomalous
aortopulmonary or bronchial collateral arteries detected during post-operative
cardiac catheterization studies [2]. Flow through these vessels is trivial to
mild in the majority of patients and appears to be of no hemodynamic
significance, but a few patients have pulmonary edema and congestive heart
failure as well as hemoptys is due to enlarged collateral arteries.
Though pre-operative angiography revealed
small aortopulmonary vessels in this patient, its diminutive size may have
dissuaded us from further investigation or aggressive treatment. Moreover, the
increased pulmonary venous return seen during the operation did not affect our
ability to wean him from cardiopulmonary bypass. Unexpectedly, the small
collateral arteries became enlarged and distorted after the operation, which
caused pulmonary hyperperfusion and airway haemorrhage with hypoxia. The reason
for the dilation of the aortopulmonary collaterals remains unclear; some
researchers speculated that this may relate to hyperoxia associated with
cardiopulmonary bypass and/or lower pulmonary vascular resistance associated
with general anaesthesia [3].
Unexplained pulmonary hypercirculation and
airway haemorrhage after ASO could be an indicator of anomalous enlarged
collateral arteries. The main responsible vessels for bleeding in the present
case included one aberrant right BA and two aortopulmonary collaterals, all of
them originated from the subclavianarteries. Selective embolization of systemic
collaterals or BA is a well-established procedure that has been widely used for
the treatment of hemoptysis from a variety of causes, it aims to reduce the
perfusion pressure to the fragile pathological collateral arteries that are
usually responsible for hemoptysis [4].To achieve this, all abnormal appearing
collateral arteries should be embolized if possible.
While there have been no controlled studies
comparing embolic agents, reported materials include gelatin sponge, polyvinyl
alcohol particles, spherical embolics, coils, and n-butylcyanoacrylate [5].
Shunts to the pulmonary circulation as large as 325 μm have been described, and
therefore, the particles used are usually greater than 350 μm in size [4]. In
this case, we used Embosphere microsphere (Merit Medical, USA) with a diameter
of >500 um to achieve distal embolization to reduce recurrence rate of
hemoptysis , and also placed microcoils in the trunk of the responsible vessels
to ensure immediate effect of hemostasis.
In conclusion, small aortopulmonary vessels detected preoperatively may dilate during or after surgery, and cause extra-pulmonary blood supply and hemoptysis, adversely affect the postoperative clinical course. It’s reasonable to occlude these vessels as much as possible even they seemed trivial and irrlevent before surgery. Earlier investigations such as angiography should be performed when the post-operative course is suggestive of pulmonary over-circulation, embolization can be a treatment option in children with abnormal vasculature bleeding. It is an effective and safe method of treatment for hemoptysis secondary to a variety of causes.
- Lim
HG, Kim WH, Lee JR, Kim YJ (2013) Long-term results of the arterial
switchoperation for ventriculo-arterial discordance. Eur J Cardiothorac
Surg 43: 325-334.
- Prifti
E, Ademaj F, Baboci A, Kajo E, Vanini V (2015) Coil embolization of an
anomalous bronchial artery originating from the left subclavian artery
following arterial switch operation: a case report .J Med Case Rep 9: 55.
- Sugimoto
A, Ota N, Sakamoto K (2016) Pulmonary haemorrhage due to an aortopulmonary
collateralartery after arterial switch. Cardiology in the Young 26:
579-581.
- Panda
A, Bhalla AS, Goyal A (2017) Bronchial artery embolization in hemoptysis:
a systematic review. Diagn Interv Radiol 23: 307-317.
- Roebuck
DJ, Barnacle AM (2008) Haemoptysis and bronchial artery embolization in
children. Paediatr Respir Rev 9: 95-104.
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