J Neurosurg 77:134-138, 1992

Emergency embolectomy for embolic occlusion of the
middle cerebral artery after internal carotid artery balloon
test occlusion
Case report
MARK E. LINSKEY,M.D., LALIGAM N. SEKHAR,M.D., AND STEPHEN T. HECHT, M.D.

Department of Neurological Surgery, University of Pittsburgh School of Medicine, and The Centerfor
Cranial Base Surgery, Presbyterian University Hospital, Pittsburgh, Pennsylvania, and the Departments
of Radiology and NeurologicaI Surgery, University of California at Davis, Sacramento, California
~" Balloon test occlusion of the internal carotid artery (ICA) is useful in preoperatively assessing the risk of
temporary occlusion or permanent sacrifice of the carotid artery. The incidence of symptomatic complications
from this procedure is 1.7%. The case is reported of a 57-year-old woman in whom a balloon test occlusion
of the left ICA was attempted. She developed a left ICA dissection/occlusion with subsequent embolization to
the left middle cerebral artery, leading to fight-sided hemiplegia and expressive aphasia. She was successfully
treated by an emergency embolectomy followed by surgical repair of the left ICA, with an excellent outcome.
This case represents the most serious complication encountered by the authors in more than 300 balloon test
occlusions. Means of avoiding this complication during balloon test occlusion as well as the important factors
in managing this problem are emphasized.
KEY WORDS

9 carotid artery occlusion

embolization

9

A

15-MINUTEclinical test of internal carotid artery
(ICA) balloon occlusion followed by an ICAoccluded stable xenon/computerized tomography (Xe/CT) cerebral blood flow (CBF) study has become a standard preoperative protocol at our institution
for evaluating the risk of temporary occlusion or permanent sacrifice of the carotid artery. 45 While it is
generally a safe procedure, occasional complications
occur even in experienced hands. We report a case of
ICA dissection/occlusion with subsequent embolization
to the left middle cerebral artery (MCA); this represents
our most serious complication to date resulting from
balloon test occlusion. The overall safety of balloon test
occlusion, the means of avoiding this complication, and
important principles for successfully managing this
problem are emphasized.
Case Report

This 57-year-old fight-handed woman presented with
a 2-month history of progressive left retro-orbital pain
and intermittent left hemispheric headaches.
Examination. Angiography revealed a giant left in134

'

balloon occlusion

9

cavernous sinus

9

middle cerebral artery

tracavernous aneurysm extending laterally from the
anterior genu of the carotid siphon (Fig. 1). A 1-cm
right-sided intracavernous aneurysm and a small fight
MCA aneurysm were also noted; both of these were
asymptomatic. Angiography demonstrated good crossfilling of the left MCA from a right ICA injection via
the anterior communicating artery.
The patient's neurological examination was normal.
Because of the severity and progressive nature of her
retro-orbital pain, ~oand since the aneurysm arose from
the anterior genu of the carotid siphon and was therefore at some risk for subarachnoid hemorrhage, 9"~~ a
decision was made to treat her left intracavernous aneurysm. Magnetic resonance (MR) imaging showed that
the aneurysm contained a significant amount of intraluminal thrombus, which could lead to distal embolization if intra-aneurysmal balloon occlusion was
attempted. Since the presence of two contralateral aneurysms made carotid sacrifice undesirable, we decided
to clip the aneurysm surgically. ~ Preoperative assessment of the patient's ability to tolerate temporary ICA
occlusion during surgery was indicated, and she was

J. Neurosurg. / Volume 77~July. 1992

Emergency embolectomy after balloon test occlusion

FIG. 1. Leftinternal carotid angiogram, anteroposterior view,
demonstrating a giant left intracavernous aneurysm.

scheduled for a 15-minute clinical test of ICA balloon
occlusion followed by an ICA-occluded Xe/CT CBF
study.
Test Occlusion. Standard Seldinger technique and
local anesthesia were used to insert a No. 5 French
double-lumen Swan-Ganz catheter via a No. 6 French
sheath into the fight femoral artery. The catheter was
introduced into the left common ICA and, after injection of a 2000-U bolus of heparin, was directed into
the left ICA. Difficulty was encountered in trying to
position the catheter at the C-2 vertebral body level for
final balloon inflation. The catheter was withdrawn to
the level of the carotid bifurcation and contrast medium
was injected. A carotid artery dissection with complete
occlusion of the ICA at the level of the C-3 vertebral
body was noted (Fig. 2A). The ipsilateral superficial
temporal artery was quite small.
Since the patient was clinically asymptomatic, she
was hydrated intravenously and was taken to the CT
scanner for a Xe/CT CBF study. Despite intravenous
hydration and a spontaneous systolic blood pressure of
180 to 190 mm Hg, she suddenly developed expressive
aphasia and fight-sided hemiplegia during the study
although she maintained a normal level of consciousness. The Xe/CT CBF study revealed low blood flow
(10 to 18 cc/100 gin/rain) in the left MCA territory
(Fig. 2B). Distal embolization from the ICA dissection
was suspected and the patient was quickly returned to
the angiography suite where a right ICA injection demonstrated loss of the previously present collateral crossfilling via the anterior communicating artery. She was
taken as an emergency to the operating room, where
she was endotracheally intubated and etomidate coma
was induced with burst suppression confirmed by electroencephalography. Her systolic blood pressure continued in the 180- to 190-mm Hg range.
Operation. A left frontotemporal craniotomy with
orbital osteotomy was performed. After the dura was

J. Neurosurg. / Volume 77/July, 1992

RG. 2. A: Digital subtraction common carotid anglogram demonstrating an internal carotid artery dissection with
lumen occlusion at the level of the C-3 vertebral body. B: A
stable xenon/computerized tomography cerebral blood flow
study performed after the patient developed right-sided hemiplegia and expressive aphasia. Low blood flow is seen in the
left middle cerebral artery distribution (10 to 18 cc/100 gin/
rain) compared with normal flow in all other vascular distributions (50 to 55 cc/100 gin/rain). The three regions of
interest displayed are in the contralateral anterior cerebral
artery (1), middle cerebral artery (2), and posterior cerebral
artery (3) distributions.

opened and the sylvian fissure split, the supraclinoid
carotid artery, the carotid bifurcation, and the proximal
anterior cerebral artery were inspected and found to be
pulsatile. An embolus was encountered occluding the
main branch of the MCA just beyond the carotid
bifurcation, and a small clot was seen at the origin of
one of the MCA perforating vessels. After proximal and
distal temporary clips were placed, an arteriotomy onequarter the circumference of the involved vessel was
performed over the embolus (Fig. 3). The distal temporary clip was removed and the distal portion of the
embolus "milked" free with good back-bleeding. The
same procedure was then repeated for the proximal
portion of the embolus. The arteriotomy was then
closed with 10-0 nylon interrupted sutures. The perforator clot could not be removed without the sacrifice of
that vessel so it was left in place. The total elapsed time
from her ictus in the CT scanner until re-establishment
of MCA blood flow was 489 to 5 hours.
A left cervical carotid exploration was then performed. The carotid bifurcation was free of clot or
intimal tear. A second arteriotomy over an area of discoloration 4 cm above the bifurcation revealed a 0.5cm transverse intimal tear. There was no intraluminal
clot, but blood clot beneath the intima was removed
and the flap tacked down with three 6-0 Prolene sutures.
Vigorous back-bleeding from the distal ICA was confirmed and the arteriotomy was closed.
The left intracavernous aneurysm was explored after
radical resection of the anterior clinoid artery and sectioning of the falciform ligament of the optic nerve. A
portion of aneurysm neck was visualized in the cli135

M. E. Linskey, L. N. Sekhar, and S. T. Hecht

FIG. 3. Intraoperative photographs after splitting the sylvian fissure and exploring the middle cerebral
artery. A: An area of discoloration was noted in the main trunk of the middle cerebral artery. After isolating
the segment between temporary, clips, an arteriotomy was performed and the embolus was delivered from the
vessel lumen. B: The arteriotomy was then closed and the temporary, clips were removed, restoring blood
flow to the middle cerebral artery, territo~,.

noidai space but the majority of the neck and the substance of the aneurysm lay beneath the proximal dural
ring. The aneurysm neck was very wide and multiple
attempts at clip placement led to ICA occlusion, confirmed by intraoperative angiography. The aneurysm
clip was removed and the aneurysm was briefly trapped
between temporary aneurysm clips. We then opened
the aneurysm, performed a thrombectomy, and reconstituted the ICA with interrupted 7-0 Novofil sutures.
A final intraoperative angiogram demonstrated good
left ICA flow with exclusion of the intracavernous
aneurysm and good filling of the left MCA.
Postoperative Course. Postoperatively, the patient
was maintained on a course of subcutaneous heparin,
5000 U twice daily. Her speech was normal and her
fight hemiplegia had improved, leaving residual mild
right arm weakness. She also had a partial left thirdnerve paresis as a result of her cavernous sinus exploration. Follow-up MR images revealed a small area of
infarction in the left basal ganglia, presumably from the
perforator embolus (Fig. 4A). Her distal MCA territory
appeared normal. Follow-up angiography revealed good
left ICA flow, exclusion of the left intracavernous aneurysm, and good filling of the left MCA (Fig. 4B). At
examination 16 months after surgery, she has returned
to homemaking, her speech is normal, and she has no
demonstrable cranial nerve deficit or motor weakness
on physical examination.

Discussion

Balloon Test Occlusion
The 15-minute clinical balloon test occlusion followed by an ICA-occluded Xe/CT CBF study is extremely useful in the preoperative assessment of the
risk of temporary occlusion or acute sacrifice of the
ICA.4'e It has an established role in the preoperative
136

assessment of patients with tumors involving the skull
base ~6-1s or with vascular lesions below the circle of
Willis.1 ~.~7The balloon test occlusion and Xe/CT CBF
study replace the cross-compression angiogram, which
is too often unreliable. 6 While the clinical balloon test
occlusion has been successfully used by itself for endovascular procedures, 2 the ICA-occluded Xe/CT CBF
study identifies an additional subset of patients with
marginal CBF reserves who may be at risk for delayed
ischemia with long-term ICA occlusion, especially if
they experience periods of hypotension or decreased
blood volume.
The clinical balloon test occlusion is generally a safe
procedure. Of 300 balloon test occlusion procedures
performed over the last 5 years at our institution, there
were complications in 11 (3.7%). 22 Six (2%) were
asymptomatic ICA dissections that did not require surgical intervention; one (0.3%) was an ICA dissection
leading to ICA occlusion and distal MCA embolization;
and four (1.3%) consisted of neurological deficits that
persisted after balloon deflation. Of the latter four, one
patient returned to baseline condition within 24 hours,
one returned to baseline within 1 week, and two were
left with minimal but persistent dysphasia. Since neurological deficits due to decreased blood flow all reverse
within minutes after balloon deflation, these four patients most likely sustained small distal emboli from
either the catheter tip or an unrecognized dissection,
despite full systemic heparinization.
Care must be taken when positioning the catheter to
avoid dissection, as occurred in this case. However,
most of the dissections associated with balloon test
occlusion have been related to balloon inflation once
the balloon is in its final position. Our criterion for
adequate occlusion of the ICA with balloon inflation
has been to inflate to the point where the balloon just
begins to deform from a spherical to cylindrical shape

J. Neurosurg. / Volume 77~July, 1992

Emergency embolectomy after balloon test occlusion

FIG. 4. A: Magnetic resonance image (TR 450 msec, TE
15 msec, 2 excitations), axial view, 11 months after surgery
demonstrating a small left basal ganglia infarction, presumably
resulting from the embolus in a middle cerebral artery (MCA)
perforator which was noted at surgery. The rest of the left
MCA distribution appears normal. B: Follow-up angiogram
8 days after surgery demonstrating good left internal carotid
artery, flow, exclusion of the left intracavernous aneurysm
from the circulation, and good filling of the left MCA.

as visualized by fluoroscopy. We are currently investigating whether adequate occlusion might be achieved
and confirmed prior to this point in an effort to reduce
barotrauma to the intima. Possibilities include inflating
just to the point of stasis of the test contrast injection
and/or inflating just to the point of blood pressure drop
as measured via the distal Swan-Ganz port/9 An additional safety measure would be to transduce the pressure
directly within the catheter balloon to prevent inadvertent overinflation. It is also important to position the
catheter so that the balloon inflates in a straight segment
of the cervical ICA. If the catheter tip lies within a bend
or loop, the tip may impale or abrade the vessel wall
upon balloon inflation, leading to intimal damage. Finally, the catheter may have entered the ICA too soon
after delivery of the heparin bolus for the patient to
have been fully systemically heparinized at the time of
vessel injury. This may have contributed to the amount
of blood clot that formed in our patient.
Any new neurological deficit that develops during
balloon test occlusion and does not quickly clear after
balloon deflation should lead one to suspect a distal
embolus. Aggressive measures should be taken to identify and treat such emboli. Possibilities for treatment of
patients with demonstrable emboli who do not improve
following elevation of blood pressure and intravascular volume expansion include intravascular fibrinolytic therapy, s,~3 extracranial-to-intracranial bypass surgery, 24 or emergency embolectomy.'2""23
Embolectomy
The first report of emergency embolectomy for acute
occlusion of the MCA was by Welch 2s in 1956. A review
J. Neurosurg. / Volume 77~July, 1992

in 1985 found 24 cases reported in the literature and
presented 19 cases from the Mayo Clinic all operated
on within 24 hours. ~2Since that time we have identified
nine additional reported cases treated within 24
hours. ~'~s2~ Embolectomy was chosen in this case because the carotid artery dissection/occlusion prevented
catheterization for local fibrinolytic agent infusion and
because the patient had a small ipsilateral superficial
temporal artery. Since she clinically tolerated ICA occlusion so long as there was collateral flow from the
contralateral side, we decided to re-establish MCA flow
via contralateral collaterals by performing the embolectomy before proceeding with repair of the carotid artery
dissection.
Several factors probably contributed to the successful
outcome of this case. It is well known that the likelihood
of infarction after ischemia is dependent on both the
degree of reduced blood flow and the duration of the
ischemia. 7 Experimental evidence suggests that embolectomy after acute MCA occlusion must be performed
within 3 to 6 hours in order to have a fair likelihood of
S u c c e s s . H4'2~ The fact that our patient's ictus occurred
in a monitored setting allowed us to proceed rapidly
and achieve revascularization within 5 hours. Meyer, et
al., ~2 have shown that fibrin-platelet clots are technically easier to remove successfully than friable atheromatous emboli. Emboli that result from balloon test
occlusion are usually fresh fibrin-platelet clots. Finally,
optimizing our patient's medical management, including early hydration and volume expansion, maintaining
a hypertension state, and placing her in etomidate coma
in order to reduce the metabolic demands in the ischemic region, may have limited the amount of damage
that was caused during the 489to 5 hours of ischemia or
may have enlarged the window of time available to us
for successful revascularization with a good outcome.
Acknowledgment
The authors thank Tricia Pinkerton for assistance with
preparation of the manuscript.
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Manuscript received September 19, 1991.
Accepted in final form December 11, 1991.
Address reprint requests to: Laligam N. Sekhar, M.D.,
Department of Neurological Surgery, Room 9402, Presbyterian University Hospital, 230 Lothrop Street, Pittsburgh,
Pennsylvania 15213.

J. Neurosurg. / Volume 77~July, 1992