Keywords
subclavian artery - pseudoaneurysm - endoleak - covered stent-graft - endovascular
Introduction
Subclavian artery (SCA) pseudoaneurysm is an uncommon pathology caused by a penetrating
or blunt trauma, or it may be iatrogenic, caused by inadvertent arterial puncture
during central venous catheterization. Surgical resection and reconstruction are technically
difficult and require sternotomy or a clavicular resection, especially when the lesion
is present in the proximal third of the SCA. Endovascular management options include
stent-assisted coiling, covered stent graft placement, or percutaneous thrombin injection.[1]
[2]
[3]
[4]
[5] Placement of covered stent graft is considered the most preferred technique; however,
it requires lack of tortuosity of the vessel and sufficient landing zone to protect
the ipsilateral vertebral artery (VA). Endoleak after endovascular stenting remains
an Achilles' heel of endovascular repair, mostly reported with aortic aneurysms.[6] We report a case of type I endoleak occurring after endovascular covered stent placement
to treat a traumatic pseudoaneurysm of the proximal left SCA.
Case Report
A 20-year-old man presented with pulsatile swelling in the left supraclavicular region
for the last 2 weeks, following a stab wound in the left supraclavicular region 15
days ago. The patient was diagnosed with pseudoaneurysm from the left SCA by a color
Doppler done from an outside center and was referred to the interventional radiology
unit for endovascular management. Computed tomography (CT) angiography showed a large
(2.2 × 1.8 × 3.6 cm) partially thrombosed saccular pseudoaneurysm in the left supraclavicular
fossa arising from the anterior aspect of the proximal left SCA located between the
origins of the thyrocervical (TC) trunk and the costocervical (CC) trunk. The neck
of the aneurysm measured 8.8 mm. Proximally, the distance of the site from the origin
of the VA, TC trunk, and internal mammary arteries was approximately 2.2, 1.6, and
1.6 cm, respectively. Distally, the distance from the CC trunk was 1.8 cm. The diameter
of the VA distal to origin of the left VA was 6 mm. Considering the neck size (8 mm),
and proximity with VA, we decided to treat the patient with a 30 × 8 mm covered stent
graft.
A 5-Fr H1 catheter was positioned at the origin of the left SCA using a 6-Fr sheath
via the transfemoral approach. Digital subtraction angiography (DSA) showed the wide
neck aneurysm, and precise relation of aneurysm in the neck and the VA, following
which a guidewire was passed across to the left axillary artery, and was exchanged
with ultra-stiff guidewire (0.035 inches) through a multipurpose catheter. A 6-Fr
vascular access sheath was exchanged with a 9-Fr sheath and a 8 mm × 30 mm covered
stent (Department of Radiodiagnosis and Imaging Covera Plus, Vascular Covered Stent,
Angiomed GmbH & Co., Bard, Karlsruhe, Germany) was placed and deployed across the
aneurysm neck with the proximal landing zone nearly 1 cm from the VA. Immediate DSA
run and a CTA performed 3 days later showed complete obliteration of the pseudoaneurysm.
The patient was started on 325 mg aspirin with intention to change to 75 mg after
1 week. The patient was discharged with proper counseling and follow-up after 1 week
was advised ([Fig. 1]).
Against the advice to avoid exaggerated movement of the procedural site, the patient
engaged in strenuous occupational activity. Two weeks after the procedure, the patient
had a repeated trauma in the form of fall from motor cycle, following which the swelling
increased in size, became pulsatile, became progressively painful, with decreased
muscle power of the left upper limb. A Doppler sonography performed revealed a leak
at the proximal and distal ends of the stent and the left radial artery showed low-resistance
monophasic waveform ([Fig 2]). CTA confirmed the presence of endoleaks at the proximal and distal ends of the
stent and the proximal end was in close proximity to the VA. The patient denied any
repeat procedure at that time predominantly due to financial reasons and poor affordability.
The patient again presented to us 1 month later, with increased swelling, excruciating
pain, and left upper limb paraparesis. CTA showed a large recurrent pseudoaneurysm
(4 × 6 cm), with an 8-cm surrounding hematoma that was compressing the left VA ([Fig 2]). After consultation with the vascular surgeon, the decision was made to treat this
pseudoaneurysm with a longer covered stent with protective VA embolization using coils.
Right VA angiogram revealed opacification of both posterior cerebral arteries (PCA).
Anterior spinal artery (ASA) was not arising from the right VA. DSA run through the
left SCA showed that the left VA was not related to the site of the endoleak. This
prompted us to preserve the left VA and a vascular 8 mm × 100 mm covered stent (Covera
Plus, Angiomed GmbH & Co. Bard) was deployed with proximal landing zone just distal
to the VA origin ([Fig 3]). To relieve the mass effect and brachial plexopathy, 25 mL of blood was aspirated
from the supraclavicular hematoma. Postprocedure angiography and CT angiography done
3 days later showed complete occlusion of pseudoaneurysm. This time, the patient was
started on 75 mg of clopidogrel once daily during the first week and subsequently
replaced by 75 mg of aspirin twice daily. After consultation with the cardiothoracic
surgery department and apprehension about infection, no additional local percutaneous
intervention was tried and the patient was put on routine follow-up to monitor the
decrease in size of associated hematoma and improvement of the left upper limb muscle
power. at 2 months of follow-up, the swelling significantly reduced, and there was
relief in pain and improvement in motion. Color Doppler did not reveal any subsequent
evidence of recurrence and there was significant reduction in the size of hematoma.
Discussion
Recurrence of the pseudoaneurysm after covered stent placement is rare and has been
reported mostly due to filling by the branches from the ipsilateral common carotid
artery, VA, and TC or CC trunk, categorized as type II endoleak. Very few cases (around
10) have been reported discussing the management of recurrent endoleaks following
initial stenting of an SCA traumatic pseudoaneurysm. They are usually treated by re-stenting
or with additional local percutaneous intervention or followed up for spontaneous
resolution.[6] We report this case of type I endoleak following endovascular management of SCA,
manifesting as a leak from both proximal and distal ends of the stent graft. Type
I endoleaks are caused by inadequate seal at the proximal and distal ends of a stent
graft and have a high risk of rupture.[7] We presumed that the strenuous activity immediately after the procedure leading
to recurrent motion of SCA against the first rib and recurrent trauma might have led
to leaks at the proximal and distal ends. The length of the covered stent (3 cm in
the initial procedure), which enabled a little over 1 cm margins from the neck of
the lesion, could have been deficient in providing adequate seal at the margins. This
case highlights the requirement of rigorous counseling of the patients against strenuous
activity after discharge, and for routine follow-up to monitor the procedure site.
Treatment of recanalized SCA pseudoaneurysm can be done via surgical resection, percutaneous
glue/thrombin injection, or by placement of a longer covered stent.[5]
[8]
[9] Due to the proximity of the VA from the proximal leakage site, preserving the VA
may compromise the stability of the proximal landing zone. Xu et al have reported
the application of covered stent in a repeatedly regrowing iatrogenic SCA pseudoaneurysm
near the origin of the VA, in which coiling of covered stent was placed across the
VA as well as SCA pseudoaneurysm and the VA stump was coiled to prevent retrograde
filling of the lesion through deep and ascending cervical collaterals and potential
embolic source.[9] It should be noted that closure of the VA should be preceded by an angiogram of
the contralateral VA to document sufficient collateral filling into the ipsilateral
posterior circulation and identification of the origin of the ASA from the contralateral
VA.[9] In our patient, we could not identify ASA from contralateral VA angiogram and thus
we did not occlude the left VA, which otherwise would have led to spinal cord infarct.
