Internal Carotid Artery Dilatation Induced by General Anesthesia: Technical Observation

Abstract

Technical Observation
General anesthesia exposure may increase the diameter
of the parent vessel during flow-diverting stent placement of the large distal cervical and petrocavernous
internal carotid artery (ICA) aneurysm. Remeasurement
of the parent vessel during general anesthesia is advisable for the correct selection of the size of the flowdiverting implant.
Case Description
A 28-year-old previously healthy right-handed man presented with two episodes of left hemispheric transient
ischemic attacks manifested by the right upper extremity
clumsiness, numbness, and expressive aphasia in spite
of medical treatment with antiplatelet medication. Neurologic examination was unremarkable and the MRI of
the brain was negative for acute ischemic stroke. MR
angiography showed a large aneurysm at the junction of
the distal cervical and petrous segment of the left ICA.
Diagnostic cerebral angiogram under moderate sedation
confirmed a focal arterial stenosis at the junction of the
distal cervical ICA and the proximal petrous segment of
the intracranial ICA complicated with a large pseudoaneurysm consistent with arterial dissection. The proximal parent vessel was severely tortuous and redundant
with a 180° loop. The pseudoaneurysm measured 10
mm in its major diameter and the neck measured 5 mm
(Figure 1). The neck of the pseudoaneurysm contains a
large intimal flap that projected against the ascending
(antegrade) arterial blood flow. The parent vessel proximal to pseudoaneurysm measured 5.3 mm at its major
diameter. We proposed endovascular treatment using
flow-diverting stent placement with a 5 × 30 mm pipeline embolization device (PED; eV3 Endovascular, Plymouth, MN, USA) to cover the aneurysm, since ICA
vessel diameter was less than 5 mm, except for the segment proximal to pseudoaneurysm measuring 5.3 mm.
Patient was placed on the dual antiplatelet regimen
(Aspirin 85 mg plus Clopidogrel 75 mg daily) 5 days
prior to the procedure and scheduled under general anesthesia. The follow-up angiogram showed an interval
worsening of the luminal stenosis of the parent vessel
and an increase in the size of the pseudoaneurysm.
Moreover, the entire ICA was dilated. The parent vessel
measured up to 6.7 mm, making it unsuitable for placement of even the 5 mm PED, which is the largest available size and can accommodate vessel lumen up to 5.25
mm (Figure 2). Not only the extracranial ICA but also the supraclinoid segment of the intracranial ICA was
dilated (Figure 3). The increase in diameter in the ICA
after placing the patient on general anesthesia was not
subtle and exact measurement showed up to a 20%
increase in the vessel diameter. The increase in the size
of the carotid artery was reversible, as proven by a 24-
hour follow-up cerebral angiogram performed with the
patient awake that showed a return of the vessel diameter to its baseline. The anesthetic medication used during
the induction and maintenance of general anesthesia
comprised fentanyl, midazolam, propofol, lidocaine, and
volatile inhaled anesthetic. Paralysis was achieved using
rocuronium. All medications were administered at standard doses. There were no adverse effects during induction or maintenance of general anesthesia. The patient
remained hemodynamically stable throughout the GA
period. The lesion was later treated through endovascular stent-assisted coil embolization using the “jailing
technique” with the patient awake during the procedure.
A 5.5 × 33 mm low-profile visualized intraluminal support (LVIS Blue; Microvention, Tustin, CA, USA) stent
was used along with bare metal detachable coils (Figure
4). The patient was discharged home the next day without complications.