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Ischemic stroke

CASE REPORT

Paradoxical cerebral air embolism causing large
vessel occlusion treated with endovascular aspiration
Patrick J Belton,1 Ashish Nanda,2 Syeda L Alqadri,3 Gurpreet S Khakh,3
Premkumar Nattanmai Chandrasekaran,3 Christopher Newey,3 William E Humphries1
1
Division of Neurosurgery,
University of Missouri Columbia
School of Medicine, Columbia,
Missouri, USA
2
SSM Health Medical Group,
Fenton, Missouri, USA
3
Department of Neurology,
University of Missouri Columbia
School of Medicine, Columbia,
Missouri, USA

ABSTRACT
Cerebral air embolism is a dreaded complication of
invasive medical procedures. The mainstay of therapy for
patients with cerebral air embolism has been hyperbaric
oxygen therapy, high flow oxygen therapy, and
anticonvulsants. We present a novel therapeutic
approach for treatment of cerebral air embolism causing
large vessel occlusion, using endovascular aspiration.
Our patient developed a cerebral air embolism following
sclerotherapy for varicose veins. This caused near total
Correspondence to
occlusion of the superior division of the M2 segment of
Dr W E Humphries, Division
of Neurosurgery, University of
the right middle cerebral artery. Symptoms included
Missouri Columbia School of
unilateral paralysis, unintelligible speech, and
Medicine, Columbia, MO 65212,
hemianopia; National Institutes of Health Stroke Scale
USA; ​humphriesw@​health.​
(NIHSS) on presentation was 16. The air embolism was
missouri.​edu
treated using a distal aspiration technique. Angiography
Republished with permission
following aspiration showed Thrombolysis in Cerebral
from BMJ Case Reports
Infarction 2B reperfusion. Following aspiration, the
Published 18 July 2016;
patient was re-examined; NIHSS at that time was 4. At
doi:10.1136/bcr-2016-012535
1 month follow-up, the modified Rankin Scale score was
1 and NIHSS was 1. Treatment of cerebral air embolism
Accepted 20 June 2016
Published Online First
is discussed.
25 July 2016

BACKGROUND
Cerebral air embolism is a potentially devastating
sequela of invasive medical procedures. In our case,
the patient developed cerebral air embolism after
sclerotherapy for varicose veins, a rare but known
complication of this procedure.1 Treatment has
mainly been systemic, with hyperbaric or high flow
oxygen.2 Despite these measures, the fatality rate
for these patients is 20% or higher in certain
series.3 Here we present the novel use of a previously described technique4 for the treatment of
cerebral air embolism using endovascular aspiration
in a patient who presented with acute hemiplegia
and dysarthria secondary to an intracranial air
embolism. Cerebral endovascular aspiration of air
occluding a large vessel soon after symptom onset
produced a remarkable recovery in the patient.

CASE PRESENTATION

To cite: Belton PJ, Nanda A,
Alqadri SL, et al.
J NeuroIntervent Surg
2017;9:e14.

The patient was a 73-year-old right handed
Caucasian male with a past medical history significant for acute ischemic stroke 27 years prior
without any residual deficits; skull fracture, traumatic subdural hematoma, and cerebral contusion
7 years prior; cardiovascular disease; hypertension
and hyperlipidemia; and was receiving sclerotherapy for symptomatic varicose veins resistant to
compression socks at an outpatient surgery center.
This was the sixth time that the patient had

received this therapy, reportedly without prior complication. The patient was given 12 mL of sodium
tetradecyl sulfate 1% foam solution injected into
the affected left leg veins under ultrasound guidance. The patient developed sudden onset left-sided
weakness, facial droop, and speech difficulties 15–
20 min after the injections. He was transported by
ambulance to the University of Missouri Hospital
for evaluation and treatment.
On arrival, approximately 25 min after symptom
onset, the patient’s National Institutes of Health
Stroke Scale (NIHSS) score was 16 (complete hemianopia, major facial paralysis, left upper extremity
and lower extremity hemiplegia, mild to moderate
decrease in sensation on left, near unintelligible
speech or unable to speak, and extinction).

INVESTIGATIONS
Non-contrast and CT angiography of the head and
neck were completed within 15 min of arrival. A
non-contrast CT scan revealed no evidence of intracranial hemorrhage but was notable for hypodense
foci concerning for air in the right sylvian fissure
and within the subarachnoid spaces of the right
frontal lobe (figure 1). CT angiography was notable
for punctate air within the right M2 middle cerebral artery (MCA) with severe narrowing of the
right MCA superior division (figure 2).

TREATMENT
Tissue plasminogen activator was not administered.
The patient was taken emergently to the endovascular suite. After arterial catheterization, digital subtraction angiography was performed. Intracranial
views of the right internal carotid artery injection
revealed an occlusion of the superior division of the
right MCA with significantly diminished anterior
grade flow distal to this (figure 3). After identification of the right superior division MCA occlusion, a
5 Fr vertebral catheter was exchanged for a Neuron
088 guide catheter (Penumbra, Almeda, California,
USA) using a Rosen exchange length wire. The
guide catheter was positioned in the cervical
portion of the right internal carotid artery. An Ace
64 (Penumbra) reperfusion catheter was directed
over a Headway 17 microcatheter (Microvention,
Tustin, California, USA) and a Synchro 2 microwire
(Stryker Neurovascular, Fremont, California, USA)
and positioned in the superior M2 division of the
right MCA. The Headway 17 and microwire were
removed and the Ace 64 reperfusion catheter was

Belton PJ, et al. J NeuroIntervent Surg 2017;9:e14. doi:10.1136/​neurintsurg-​2016-​012535.​rep

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Ischemic stroke

Figure 3 Digital subtraction angiography, internal carotid artery
injection, showing split flow in the vessel lumen, around the presumed
air bubble (arrow).

Figure 1 Non-contrast axial CT showing air density material near the
expected bifurcation of the middle cerebral artery (arrows).
then connected to a mechanical suction device (Penumbra) for
aspiration and pulled slowly back into the guide catheter. This
was repeated two times.

OUTCOME AND FOLLOW-UP
Following aspiration, repeat angiography showed Thrombolysis
in Cerebral Infarction 2B reperfusion (figure 4). The procedure
was completed in 37 min (1 hour 49 min after symptom onset).

On completion of the procedure, the patient’s NIHSS was 4
(mild left upper and lower extremity drift, minor facial paralysis,
and mild dysarthria). During the procedure as well as afterwards, the patient received 2 L/min of oxygen via nasal cannula.
A brain MRI the following day was notable for some small foci
of diffusion restriction in the right frontal, parietal, and temporal lobes, but no large territory infarct (figure 5).
Echocardiogram with bubble study was notable for a right to
left shunt that increased significantly with Valsalva, consistent
with a patent foramen ovale (figure 6). The patient’s remaining
hospital stay was uncomplicated, and he was discharged to
inpatient rehabilitation on day 3 with an NIHSS score of 3. At
1 month follow-up the modified Rankin Scale score was 1 and
NIHSS was 1.

DISCUSSION
While intracranial air embolism is a known complication of
sclerotherapy1 and other medical procedures, the treatment

Figure 2 CT angiography showing air density material in the middle
cerebral artery, superior division, with minimal filling past the stenosis
(arrow).
2 of 4

Figure 4 Digital subtraction angiography, internal carotid artery
injection, after aspiration, showing recanalization and restoration of
blood flow (arrow).

Belton PJ, et al. J NeuroIntervent Surg 2017;9:e14. doi:10.1136/​neurintsurg-​2016-​012535.​rep

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Ischemic stroke
Figure 5 MRI of the brain,
performed the day following the
procedure, showing hyperintensity on
diffusion weighted imaging (left) and
apparent diffusion coefficient
hypointensity (right) on both sides of
the central sulcus.

arterial air embolism, direct aspiration has been applied, with
some promising results.12 13 To the authors’ knowledge, there
have been no reported cases of endovascular aspiration in the
treatment of patients with intracranial air embolism. We adapted
a distal aspiration technique described previously4 for treatment
of our patient with excellent results. Based on the rapid
response of our patient to aspiration of entrapped air, we
believe this may represent a new therapeutic option for certain
patients with large vessel occlusion caused by intracranial air
embolism.

Key messages

Figure 6 Echocardiography bubble study, performed with Valsalva
maneuver, showing egress of agitated saline bubbles into the left
atrium and left ventricle (arrows).

modality used in this particular case has not been reported previously and represents a novel therapeutic technique.
Air embolism is a risk for many medical procedures. Most
commonly air embolism affects the pulmonary vasculature.5
One treatment sometimes advocated for pulmonary gas embolism is right atrial gas aspiration using a central venous catheter.6 7 Arterial air embolism is less commonly encountered.
Arterial air embolism occurs via a direct introduction of air into
the arterial system, via a patent foramen ovale, in the presence
of an arteriovenous shunt, or via transmission through pulmonary capillary beds.7 Cerebral arterial air embolism has been
reported from procedures as varied as lung biopsy,8 endoscopic
gastrointestinal procedures,9 and cerebral angiograms.10
Depending on the quantity and distribution of air in the arterial system, symptoms of cerebral air embolism can range from
temporary motor weakness and headache to hemianopia, hemiparesis, convulsions, coma, and death.7 Patients like this one
who present with advanced age, mental status changes, hemiparesis, and gyriform air on initial CT are noted to have an
unfavorable prognosis.11
The mainstay of treatment in symptomatic cerebral air embolism has been hyperbaric oxygen therapy, high flow oxygen, and
anticonvulsants.10 Despite these measures, within published case
reports there is a mortality rate as high as 22%.3 11 For cardiac

â–¸ Cerebral air embolism is a potentially devastating sequela of
invasive medical procedures.
▸ The mainstay of treatment has been high flow oxygen and
hyperbaric oxygen.
â–¸ Some patients with large vessel occlusion caused by intracranial
air emboli may benefit from endovascular aspiration.

Contributors PJB, AN, SLA, GSK, PNC, and WEH all contributed equally to the
writing and editing of this submission and approved the submission. CN contributed
to the writing of the article and approved its submission.
Competing interests None declared.
Patient consent Obtained.
Ethics approval The study was approved by the University of Missouri Institutional
Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Additional data from the case (other images in the
identified studies, laboratory values) are available on request to the corresponding
author.

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intraoperative diagnosis and management of a rare complication. J Cerebrovasc
Endovasc Neurosurg 2014;16:93–7.
Cheng CK, Chang TY, Liu CH, et al. Presence of gyriform air predicts unfavorable
outcome in venous catheter-related cerebral air embolism. J Stroke Cerebrovasc Dis
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Belton PJ, et al. J NeuroIntervent Surg 2017;9:e14. doi:10.1136/​neurintsurg-​2016-​012535.​rep

Downloaded from http://jnis.bmj.com/ on January 27, 2018 - Published by group.bmj.com

Paradoxical cerebral air embolism causing
large vessel occlusion treated with
endovascular aspiration
Patrick J Belton, Ashish Nanda, Syeda L Alqadri, Gurpreet S Khakh,
Premkumar Nattanmai Chandrasekaran, Christopher Newey and William
E Humphries
J NeuroIntervent Surg2017 9: e10 originally published online July 25,
2016

doi: 10.1136/neurintsurg-2016-012535.rep
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