We present a patient with ACTA2 mutation and diffuse
vascular involvement, including bilateral fusiform internal carotid artery
(ICA) aneurysms, recurrent aortic dissections and extensive aortic
instrumentation. A large right intracranial ICA aneurysm in this patient was
treated with endovascular PED, requiring vascular access through open surgical
carotid exposure.
A 19-year-old man with ACTA2 mutation presented with a right
intracranial ICA fusiform aneurysm. His past medical history included recurrent
aortic dissections involving the arch and thoracoabdominal aorta, previously
treated with arch replacement and grafts to the innominate and left common
carotid artery, left common carotid to left subclavian bypass, and bilateral
iliac and thoracoabdominal aortic stents. In 2013, he had a right
hemispheric ischemic stroke with complete recovery after intravenous tissue
plasminogen activator.
Workup demonstrated large bilateral fusiform
petrous-cavernous ICA aneurysms, the right larger than the left . He
developed worsening headaches and significant aneurysm growth over 1 year of
follow-up, with erosion of the bone at the skull base and protrusion of the
aneurysm sac to the mesial temporal lobe.
Pre-intervention cerebral angiograms demonstrating a right internal carotid irregular fusiform aneurysm, with dysplastic appearance of the cavernous and supraclinoid internal carotid artery. Note the characteristic “straight” appearance of the middle and anterior cerebral artery distributions seen with ACTA2 mutations.
Pre-intervention cerebral angiograms demonstrating a right internal carotid irregular fusiform aneurysm, with dysplastic appearance of the cavernous and supraclinoid internal carotid artery. Note the characteristic “straight” appearance of the middle and anterior cerebral artery distributions seen with ACTA2 mutations.
Due to the risk of subarachnoid hemorrhage despite the
proximal location, the decision was made to treat the right ICA aneurysm first
with flow diversion. Given the patient’s ACTA2 mutation, recurrent dissections
and extensive aortic instrumentation resulting in an extreme angle of the right
common carotid artery off the aortic arch, a transfemoral vascular approach was
considered exceptionally difficult and high-risk. The decision was made to access
the aneurysm surgically through the cervical carotid.
Aspirin 325 mg/d and clopidogrel 75 mg/d were started 10
days prior to the procedure, with adequate platelet suppression on platelet
aggregometry testing. With the patient under general anesthesia, the neck was
prepped and draped in a sterile fashion. Following surgical exposure of the
right carotid bifurcation, an incision was made in the proximal ICA, a 6-French
Shuttle® guide sheath was introduced and the carotid incision was sutured
around the Shuttle. Heparin was administered.
A working angle for Pipeline™ embolization device (PED) deployment was obtained. Under
fluoroscopic guidance, an intermediate catheter was navigated over a standard
microcatheter and microwire to the distal cervical ICA. The microcatheter was
then positioned distal to the aneurysm. Four overlapping PEDs were deployed
successfully in a telescopic fashion from distal to proximal.
Angiography demonstrated adequate wall apposition of the PEDs at the distal and
proximal landing zones, with reduced flow to the aneurysm and
partial contrast stasis. The catheters were removed, the carotid was sutured
and the neck incision was closed, leaving a drain in place for 24 hours. The
patient went home 3 days later without complications.
ACTA2 is a gene encoding alpha-2 actin, a major component of
vascular smooth muscle. ACTA2 mutation is associated with early-age thoracic
aortic aneurysms and dissections.1 Some patients have manifestations of diffuse
smooth muscle involvement and cerebrovascular abnormalities including Moyamoya
disease and fusiform and saccular intracranial aneurysms.
Our patient with ACTA2 mutation had bilateral ICA fusiform
aneurysms. Given the worsening headaches, aneurysm growth and concern for
intradural extension, the decision was made to treat with flow diversion. In
light of the patient’s previous aortic dissections involving the arch and
descending thoracoabdominal aorta, as well as his extensive prior vascular
procedures, transfemoral access with a large guide sheath was concerning for
potential vascular complications, including new dissections or injury of the
previously dissected and replaced thoracoabdominal vessels. Furthermore, his
extensive aortic instrumentation made percutaneous femoral access and catheter
navigation through the aorta nearly impossible. Surgical exposure of the
carotid artery at the neck with access through a carotid cutdown was performed,
followed by endovascular delivery and deployment of PEDs without complications.
Notably, the patient’s brother carried the same genetic
mutation and developed aneurysms in the identical location. Our combined
surgical-endovascular approach was successfully used to treat the brother’s
aneurysm as well…
A previous study reported alternative access for a variety
of neurointerventional procedures in 21 patients. Surgical cutdown was performed in 12 patients
(8 in the carotid and 4 in the vertebral artery) and percutaneous puncture in 9
(5 in the carotid and 4 in the brachial artery), with no access-related
complications. These authors included patients between 50 and 82 years of age
in whom the intracranial vasculature could not be accessed via the transfemoral
route, mainly due to tortuosity in the aorta and supra-aortic vessels. The
transradial approach is an alternative access route for PED delivery in elderly
patients with a tortuous aortic arch.
Managing intracranial vascular lesions in patients with
significant proximal large-vessel tortuosity, aortic arch disease or
instrumentation, and genetic conditions is highly complex, due to vessel
fragility and the risk of complications. Alternative access for an intracranial
procedure should be considered in these patients. As demonstrated in the case
of this young patient with ACTA2 mutation, cervical carotid surgical cutdown
can provide optimal access, allowing a safe and efficient approach to
endovascular flow diverter treatment of a large dysplastic aneurysm.
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