Interventional
Radiology:

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

Gordhan et al.

Chronic innominate artery occlusion with hyperacute
intracranial thromboembolism: Revascularization with
simultaneous local thromboaspiration and mechanical
thrombectomy
Ajeet Gordhan1*, Jesse Vanle2
1. Department of Neurointerventional Radiology, St Joseph Medical Center, Bloomington, IL, USA
2. Department of Cardiovascular Surgery, St Joseph Medical Center, Bloomington, IL, USA
* Correspondence: Ajeet Gordhan MD, Department of Neurointerventional Radiology, St Joseph Medical Center, 2200 East Washington
Ave, Bloomington, IL, 61701, USA
(
agordhan@hotmail.com)

DOI: 10.3941/jrcr.v9i3.1750

ABSTRACT
Chronic innominate artery occlusion with acute right internal carotid
terminus thromboembolism and successful revascularization using
simultaneous local thromboaspiration and mechanical thrombectomy has not
been previously described. A 51-year-old male presented with transient left
hemiparesis. A CT angiogram of the head and neck demonstrated chronic
occlusion of the right innominate artery with no intracranial
thromboembolism. More profound symptoms recurred twelve hours after
admission. A diagnostic catheter-based angiogram confirmed occlusion of
the innominate artery and identified hyper-acute right carotid terminus
thromboembolism. Angioplasty of the innominate artery was followed by
simultaneous mechanical and aspiration thrombectomy of the right internal
carotid artery terminus.
Combination local thromboaspiration and
mechanical thrombectomy was shown in this case to be effective in achieving
a favorable clinical outcome.

www.RadiologyCases.com

Journal of Radiology Case Reports

Radiology Case. 2015 Mar; 9(3):27-36 ::

CASE REPORT

CASE REPORT
A 51-year-old male presented to the emergency room with
left-sided weakness and right facial droop. Admission NIHSS
(National Institute of Health Stroke Scale) score was 13 and
blood pressure taken from the left arm was 154/79 mmHg with
a pulse rate of 67 beats per minute. Past medical history was
significant for a 20 pack year history of smoking and was
otherwise unremarkable. There was no prior history of right
upper arm claudication, syncope, vertigo, or visual
impairment. Symptoms occurred with no prior activity of his
right upper extremity.
A non-contrast head computerized tomographic (CT)
examination identified no intracranial hemorrhage or early
Radiology Case. 2015 Mar; 9(3):27-36

changes of acute ischemic injury (Fig. 1A). A CT angiogram
(CTA) of the head and neck after initial clinical evaluation
demonstrated no carotid bifurcation stenosis or intracranial
large vessel thromboembolic occlusion (Fig. 1 B,C). A brain
MRI examination with evaluation of diffusion and apparent
diffusion coefficient (ADC) sequences demonstrated no acute
brain parenchymal infarction (Fig. 1 D,E,F). The CTA
evaluation did however demonstrate occlusion of the proximal
right innominate artery (IA) with opacification of a diminutive
right cervical internal carotid artery (ICA) relative to the
contralateral side. The non-dominant right cervical vertebral
artery (VA) and the right subclavian artery (SA) were patent.
Increased right hemispheric cortical branch vascularity relative
to the left was identified. Diminished caliber of the right
common carotid artery (CCA) and right ICA with increased
27

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

Gordhan et al.

ipsilateral hemispheric cortical branch vessels suggested
chronic IA artery occlusion with right hemispheric pial
collaterals (Fig. 2 A, B and C). No CTA findings compatible
with fibromuscular dysplasia (FMD) or vasculitis was noted.
No cervical ribs were identified. A CT perfusion study was not
performed as no intracranial thromboembolic occlusion was
identified by CTA. The Electroencephalography (EEG) study
and the serum coagulation profile were normal.

vascular territory infarction. The patient was admitted to the
ICU for monitoring overnight. He was discharged home on
aspirin with complete neurologic recovery two days after
admission. At three months follow up he remained
asymptomatic with no progression of IA stenosis by CTA.

Neurologic symptoms resolved within five hours after
onset, compatible with a transient ischemic attack. The patient
re developed acute left upper and lower extremity weakness
with mental status change twelve hours after his admission.
Hydrochlorothiazide (12.5 milligrams) as well as a nicotine
patch (21 mg per 24 hour) had been given by his primary care
caregiver. Left arm blood pressure had transiently dropped to
92/64 mm of Hg with a pulse rate of 60 beats per minute. An
emergent catheter based angiogram was requested for by the
attending vascular surgeon to definitively evaluate the aortic
arch and IA prior to surgical intervention. Due to the patient's
rapid clinical decline no repeat CTA, MRA or CT perfusion
imaging was obtained. Angiographic evaluation of the arch
demonstrated occlusion of the proximal IA with delayed
retrograde filling of the right cervical VA and post stenotic IA.
Via retrograde filling within the post stenotic distal IA,
delayed ante grade flow within the right CCA with distal
occlusion of the visualized right ICA was identified (Fig. 3 A
and B). To evaluate the delayed filling and distal occlusion, a,
5 French JB2 diagnostic catheter in tandem with a stiff Storq
Standard 300 cm .035-inch (Cordis Corporation, Miami Lakes,
FL) guidewire was advanced through the IA occlusion into the
right CCA. Digital subtraction angiography (DSA) of the right
CCA revealed carotid terminus (Carotid-T) occlusion with no
right hemispheric intracranial flow (Fig. 3C). No catheter
based angiographic findings compatible with FMD (Fibro
muscular disease) or vasculitis was identified.

Right MCA acute thromboembolic stroke from occlusion
of the IA with unsuccessful revascularization and a poor
patient outcome has been reported [1]. Right carotid-T
thromboembolism (intracranial carotid bifurcation occlusion
with involvement of A1 and M1 segments) from IA stenoocclusive disease with successful endovascular intervention
and complete clinical recovery has not been reported. CarotidT occlusions have poor clinical outcomes even after
endovascular intervention [2]. Simultaneous thromboaspiration
and mechanical thrombectomy may additionally improve
recanalization rates, particularly for carotid-T occlusions.

Angioplasty of the IA stenosis was initially performed
using a 9 mm x 40 mm over the wire EverCross angioplasty
balloon (EV3 Inc., Plymouth, MN) (Fig. 4A). Mechanical and
combined aspiration thrombectomy was preceded by intraarterial administration of 10 mg tPA (tissue plasminogen
activator). A 054 Reperfusion Catheter (Penumbra Inc.,
Alameda, CA) was navigated to the petrous segment of the
right ICA (Fig. 4B). A 6 mm x 20 mm Solitaire FR stent
retrieval system (EV 3, Plymouth, MN) was deployed within
the distal right M1 MCA trunk (Fig. 4B). The stent retrieval
system was proximally withdrawn with simultaneous
aspiration through the 054 Reperfusion Catheter using the
Penumbra aspiration pump. Retrieval of the stent system
external to the patient revealed minimal thrombus within the
stent interstices. Aspiration of the 054 catheter with a 60 mL
syringe revealed clot within the reperfusion catheter when
withdrawn external to the patient. Complete revascularization
of the carotid-T and right hemispheric branch vasculature was
achieved (Fig. 4C). Symmetric flow within the cervical
common and internal carotid arteries bilaterally as well as
within the intracranial vasculature was identified. Marked
kinking of the IA origin at the apex of the aortic arch was
noted with residual stenosis. (Fig. 3D). CT of the head post
procedurally revealed no intracranial hemorrhage or major
Radiology Case. 2015 Mar; 9(3):27-36

DISCUSSION

Etiology & Clinical Findings
Extracranial carotid artery disease accounts for 15-20% of
all ischemic strokes, the majority as a result of carotid
bifurcation disease. The gender prediction is not known for
innominate stenosis. There is a slight male preponderance for
extra-cranial carotid bifurcation disease that is often identified
with innominate stenosis. In a study of 94 patients with
innominate artery stenosis, the mean age was 62 [3].
In an extensive angiographic study, IA steno-occlusive
disease was identified in only 4% of patients [4]. This may or
may not present with posterior circulation and upper extremity
ischemic symptoms. Dizziness, visual impairment, vertigo and
syncope are the most common neurologic symptoms.
Diminished or absent upper extremity pulses ipsilateral to the
stenosis and asymmetric blood pressures are the most
consistent clinical findings in symptomatic patients. Anterior
circulation ischemic symptom in subclavian artery (SA)
stenosis is more likely consequent to extracranial carotid
bifurcation disease [5]. With IA stenosis, right hemispheric
ischemic symptoms may occur.

Imaging Findings
The right SA and right CCA arise from the IA in 99% of
cases. With proximal IA occlusion, there is retrograde flow
from the right VA into the right SA, referred to as "steal
phenomenon". Flow then occurs retrograde through the distal
IA and then ante grade into the right CCA. This alteration in
blood flow, results in chronic reduced perfusion to the right
cerebral hemisphere.
A case report identifying this
phenomenon has been shown with MR angiogram and
perfusion imaging [5]. In our patient, CT angiogram findings
of chronic IA stenosis was evidenced by the diminution in
caliber of the right carotid system reflecting diminished wall
shear stress from decreased flow and increased cortical branch
vascularity of the right cerebral hemisphere, compatible with
pial collaterals.
28

www.RadiologyCases.com

Journal of Radiology Case Reports

Interventional
Radiology:

Interventional
Radiology:

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

MR Angiography with 3D gadolinium enhanced technique
requires a shorter acquisition time, limiting motion artifact and
is useful for determining IA stenosis. 2D TOF (Time of flight)
technique provides information about the direction of flow in
the vertebral arteries. If enhancement is present in a VA on
gadolinium-enhanced MRA, but no corresponding flow-related
enhancement is seen on TOF MRA, then flow in that vessel
must be reversed. CTA can identify stenosis of the IA but does
not evaluate VA flow reversal. Chronic IA occlusion can be
determined by extra-cranial carotid artery caliber and right
hemispheric pial collaterals. CT and MR brain perfusion with
evaluation of cerebral blood flow, cerebral blood volume and
mean transit time maps can identify hypoperfusion within the
right cerebral hemisphere with significant IA stenosis. These
perfusion parameters can also be used to determine a viable
ischemic penumbra in the instance of carotid-T and or MCA
occlusion. Digital Subtraction angiography (DSA) remains the
reference standard for diagnosing and characterizing IA
stenosis and steal phenomena as well as intracranial
thromboembolic occlusion. This modality also provides
opportunity for endovascular intervention [5].

Differential Diagnosis
Anterior circulation strokes from IA thrombus formation
due to non-atherosclerotic disease have been reported in a few
case reports [6,7,8, 9]. The diagnostic differential of IA
disease with embolic phenomenon includes cervical ribs,
dissection, nephrotic syndrome hypercoagulability, thoracic
mural thrombus syndrome (TMT), FMD and vasculitis.
Prolonged IA compression at the thoracic outlet due to a
cervical rib results in fibrotic and inflammatory change
causing platelet aggregation, mural thrombus formation and
macro embolism [6]. Ischemic stroke from supra-aortic artery
dissection accounts for 10-25% of patients under the age of
fifty and is spontaneous in 60% of cases. Isolated dissection of
the IA is extremely rare and is more frequently associated with
residual dissection following repair of acute type A aortic
dissections [7]. If IA dissection is present urgent CTA and
trans-esophageal echocardiography should be performed to
exclude aortic dissection. In hypercoagulable states arterial
thrombosis is rare and assessment of hypoalbuminemia in
nephrotic syndrome may be useful in identifying at risk
patients that may benefit from early anticoagulation treatment
[8]. TMT syndrome occurs in healthy young people with risk
factors that include smoking and a family history of
atherosclerotic disease and is characterized by thrombus
formation in the aortic arch and branch vessels [9]. FMD is a
non-atherosclerotic and non-inflammatory vasculopathy that
Radiology Case. 2015 Mar; 9(3):27-36

most frequently affects renal and carotid arteries and can
involve any artery [10]. IA stenosis is also recognized in other
entities such as radiation and Takayasu's arteritis with ancillary
findings [11]. The natural history of radiation arteritis of larger
vessels spans many decades, with development of thrombosis
within the first five years, fibrotic lesions in the first decade,
and lesions resembling atherosclerotic disease after the second
decade [12]. Takayasu's arteritis is characterized by idiopathic
inflammation of the aortic arch, pulmonary, coronary, and
cerebral vessels. This presents typically in females in the
second to fourth decades with stroke, transient ischemic attack,
myocardial infarction, and upper extremity claudication [13].

Treatment & Prognosis
Percutaneous
transluminal
angioplasty
of
the
brachiocephalic vessels with or without stenting is a viable
alternative to surgery with lower peri-procedural complications
[14]. Angioplasty alone has a high failure rate. With stent
placement clinical outcomes are equivalent to surgery [15]. In
the acute stroke setting, IA angioplasty without stent
placement as performed in the case presented is favored, as it
would mitigate the requirement of immediate post procedural
anti-platelet medications. With an established infarction antiplatelet agents would increase the risk for hemorrhagic
transformation. Avoiding stent placement also facilitates
delivery of mechanical thrombectomy devices into the right
carotid system without hindrance. Stenting can be performed
electively after clinical recovery.
Risk of procedural thromboembolism into the VA and
ICA for extra-cranial vascular stent angioplasty has been
addressed with placement of distal protection devices [16].
This would be a moot point for the already occluded right
CCA in the acute setting. The value of embolic protection
within the vertebral artery is doubtful especially in the
presence of flow reversal, as was present in our patient. There
is a significant delay in establishment of antegrade flow after
stent angioplasty that ranges from 20 seconds up to a few
minutes [17], diminishing the risk of thromboembolism to the
posterior circulation.
The self-expanding retrievable and reusable Solitaire stent
retriever device mechanically engages the thrombus within its
stent struts. The device with the thrombus is then retracted
with or without flow arrest from a balloon tip guide catheter. A
recent systematic review of the effectiveness of the Solitaire
stent retriever in acute intracranial stroke revealed an 89.7%
recanalization rate with a procedure induced complication rate
of 3.4% [18]. Concurrent use of the stent retrieval device
before and after adjunctive measures that include
pharmacologic
intra-arterial
thrombolysis,
aspiration
thrombectomy with Penumbra Reperfusion catheters and stent
deployment or angioplasty was attempted in 21% of cases in
the Solitaire systematic review [18]. The Penumbra Pivotal
Stroke Trial demonstrated an 81.6% intracranial vessel
recanalization rate and a cerebral hemorrhage rate of 11.2%
using only Penumbra Reperfusion catheters [19].
Carotid-T occlusions have a large clot burden with a
dismal clinical outcome [2]. Even after endovascular
29

www.RadiologyCases.com

Journal of Radiology Case Reports

IA steno-occlusive disease is distinct from subclavian
steal as it affects the anterior and posterior circulations [5].
Patient habitus and anatomy significantly effects imaging
assessment of the vertebral and subclavian arteries.
Sonographic evaluation of the IA is limited by overlying ribs
and tracheal shadowing. In subclavian steal or significant IA
stenosis, altered vertebral artery waveforms are seen only
when the degree of stenosis is greater than 60%. Permanent
flow reversal can be seen when a SA or IA stenosis is greater
than 75% [5]. Ultrasound can be helpful in determining MCA
occlusion; however this is not frequently performed.

Gordhan et al.

Interventional
Radiology:

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

recanalization, only 21.4% achieve functional independence
[20]. Direct large caliber catheter aspiration of the internal
carotid artery was independently used in one study [21],
however for successful recanalization more than one device
was used in 50% of patients in another [20]. Simultaneous use
of the stentretriever and aspiration catheter has been referred
to as the "Solumbra" technique and has no published data to
attest to its effectiveness. Clinical outcomes have been shown
to improve after angiographic recanalization [22].
Combination
endovascular
therapy
for
intracranial
thromboembolic stroke as compared to standard intravenous
tPA alone, showed no difference in safety with no increased
benefit in clinical outcomes in a randomized controlled study.
This study was not inclusive of newer stentretriever technology
in the endovascular therapy arm. In the post hoc analysis of
this study carotid T occlusions with M1 MCA occlusions
showed greater recanalization and better outcomes with use of
combined IV tPA and endovascular therapy [23].

Innominate artery occlusive stenosis with acute carotid-T
thromboembolic occlusion requires early catheter based
angiographic evaluation for endovascular intervention.
Revascularization
using
aspiration
and
mechanical
thrombectomy at the carotid terminus simultaneously preceded
by innominate artery angioplasty is effective in establishing a
favorable clinical outcome.

REFERENCES
1. Sanchez-Ayaso P, Hernandez-Fernandez F, Ayo-Martin O,
Collado R, Segura T. Anterior circulation embolic stroke
secondary to thrombotic occlusion of the brachiocephalic
trunk: the usefulness of neurosonological studies. Rev
Neurol. 2012 Mar 1; 54(5):284-8. PMID: 22362477.
2. Rabinstein AA, Wijdicks EF, Nichols DA. Complete
recovery after early intraarterial recombinant tissue
plasminogen activator thrombolysis of carotid T occlusion.
AJNR Am J Neuroradiol. 2002 Oct; 23(9):1596-9. PMID:
12372754.
3. Azakie A, McElhinney DB, Higashima R, Messina LM,
Stoney RJ. Innominate artery reconstruction: over 3 decades
of experience. Ann Surg. 1998 September; 228(3): 402-410.
PMID 9742923.
4. Hass WK, Fields WS, North RR, Kircheff II, Chase NE,
Bauer RB. Joint study of extracranial arterial occlusion. II.
Arteriography, techniques, sites, and complications. JAMA.
1968 Mar 11;203(11):961-8.PMID:5694318.
5. Huang BY, Castillo M. Radiological reasoning: extracranial
causes of unilateral decreased brain perfusion. AJR Am J
Roentgenol. 2007 Dec; 189(6 Suppl):S49-54. PMID:
18029901.

Radiology Case. 2015 Mar; 9(3):27-36

6. J Heidt, L de Beer, GC Admiraal. A rare cause of occlusion
of the brachiocephalic trunk, resulting in fatal stroke: arterial
thoracic outlet syndrome. Neth J Crit Care-Volume15-No4August 2011. PMID: not referenced.
7. Sansone T, Baroncelli S, Tozzetti C, Berni A, Torri M.
Challenges in management of ischemic stroke secondary to
brachiocephalic artery dissection. Intern Emerg Med. 2013
Mar; 8(2):181-3. PMID: 23054410.
8. Brahmbhatt BK, Mathew A, Rajesh R, Kurian G, Unni VN.
Brachiocephalic artery thrombosis in adult nephrotic
syndrome. Indian J Nephrol. 2011 Jul-Sep; 21(3): 204-7.
PMID: 21886984.
9. Morris ME, Galiñanes EL, Nichols WK, Ross CB,
Chauvupun J. Thoracic mural thrombi: a case series and
literature review. Ann Vasc Surg. 2011 Nov; 25(8):1140.
PMID: 22023948.
10. Olin JW, Sealove BA. Diagnosis, management, and future
developments of fibromuscular dysplasia. J Vasc Surg. 2011
Mar; 53(3):826-36. PMID: 21236620.
11. Tracci MC, Cherry KJ. Surgical treatment of great vessel
occlusive disease.
Surg Clin North Am. 2009 Aug; 89(4):821-36. PMID:
19782839.
12. Butler MJ, Lane RH, Webster JH. Irradiation injury to
large arteries. Br J Surg. 1980 May;67(5):341-3.PMID:
7388329
13. Numano F., Okawara M., Inomata H., et al: Takayasu's
arteritis.
Lancet 356. (9234): 1023-1025.2000;
PMID:11041416
14. Palchik E, Bakken AM, Wolford HY, Waldman DL,
Davies MG. Evolving strategies in treatment of isolated
symptomatic innominate artery disease. Vasc Endovascular
Surg. 2008 Oct-Nov; 42(5):440-5. PMID: 18621881.
15. Van Hattum ES, de Vries JP, Lalezari F, van den Berg JC,
Moll FL. Angioplasty with or without stent placement in the
brachiocephalic artery: feasible and durable? A retrospective
cohort study. J Vasc Interv Radiol. 2007 Sep; 18(9):108893. PMID: 17804769.
16. Stiefel MF, Park MS, McDougall CG, Albuquerque FC.
Endovascular treatment of innominate artery occlusion with
simultaneous vertebral and carotid artery distal protection:
case report. Neurosurgery. 2010 Apr; 66(4):E843-4. PMID:
2030547.
17. Ringelstein EB, Zeumer H. Delayed reversal of vertebral
artery blood flow following percutaneous angioplasty for
subclavian steal syndrome Neuroradiology. 1984;26(3):18998. PMID: 6234477.
18. Koh JS, Lee SJ, Ryu CW, Kim HS. Safety and Efficacy of
Mechanical Thrombectomy with Solitaire Stent Retrieval for
30

www.RadiologyCases.com

Journal of Radiology Case Reports

TEACHING POINT

Gordhan et al.

Interventional
Radiology:

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

Acute Ischemic Stroke: A Systematic Review
Neurointervention. 2012 Feb; 7(1):1-9. PMID: 22454778.
19. Penumbra Pivotal Stroke Trial Investigators. The
penumbra pivotal stroke trial: safety and effectiveness of a
new generation of mechanical devices for clot removal in
intracranial large vessel occlusive disease. Stroke. 2009;
40:2761-68. PMID: 19590057.
20. Fesl G, Wiesmann M, Patzig M, Holtmannspoetter M,
Pfefferkorn T, Dichgans M,et al. Endovascular mechanical
recanalisation of acute carotid-T occlusions: a single-center
retrospective analysis. Cardiovasc Intervent Radiol. 2011
Apr; 34(2):280-6. PMID: 20936289.

Gordhan et al.

21. Eesa M, Almekhlafi MA, Mitha AP, Wong JH, Goyal M.
Manual aspiration thrombectomy through balloon-tipped
guide catheter for rapid clot burden reduction in
endovascular
therapy
for
ICA
L/T
occlusion.
Neuroradiology. 2012 Nov; 54(11):1261-5. PMID:
22552837.
22. Rha JH, Saver JL The impact of recanalization on ischemic
stroke outcome: a meta-analysis. Stroke 2007; 38:967-73.
PMID: 17272772.
23. Broderick JP, Palesch YY, Demchuk AM, Yeatts SD,
Khatri P, Hill MD, et al. Endovascular therapy after
intravenous t-PA versus t-PA alone for stroke. N Engl J
Med. Mar 7; 368(10):893-903. PMID: 233909232013.

www.RadiologyCases.com

Journal of Radiology Case Reports

FIGURES

Figure 1: A 51-year-old male presented with acute transient left sided weakness. Chronic innominate artery steno-occlusive
disease was identified by initial CT angiography without intracranial thromboembolic occlusion. Early recurrence and worsening
of left sided weakness prompted a catheter based angiographic study, identifying hyperacute thromboembolic occlusion at the
right carotid terminus. This was retrieved using combined local thromboaspiration and mechanical thombectomy preceded by
innominate artery angioplasty.
Findings: A: Select axial non contrast head CT image slice shows no attenuation change compatible with right hemispheric
infarction. No dense right middle cerebral artery sign compatible with thrombus is identified (black arrow). B: Maximum
intensity projection CTA shows patent right carotid terminus (thick black arrow) and right proximal middle cerebral artery (thin
black arrow). C: Curved planar sagittal reformat CTA demonstrates a normal caliber and contour of the right distal common
carotid artery, carotid bifurcation and internal carotid artery. D, E and F: Select axial FLAIR (D), axial diffusion (E) and axial
apparent diffusion coefficient (ADC) mapped sequence (F) slices show no signal change compatible with right hemispheric
infarction.
Technique: A: Axial CT mA330, 140 kV, Slice thickness 2.5mm. B: Axial CT, 480mAs, 140kV, Slice thickness 10mm, 75 ml
Isovue 370 injection at 4ml/second. C: Axial CT, 480mAs, 140kV, Slice thickness 0.63, 75 ml Isovue 370 injection at
4ml/second. D: Axial FLAIR TR 8000 TE 128.90, Slice thickness 5mm. E: Axial Diffusion, TR8600 TE80.10, Slice thickness
5mm. F: Axial ADC Axial Diffusion, TR8600 TE80.10, Slice thickness 5mm.
Radiology Case. 2015 Mar; 9(3):27-36
31

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

Gordhan et al.

Figure 2: A 51-year-old male presented with acute transient left sided weakness. Chronic innominate artery steno-occlusive
disease was identified by initial CT angiography without intracranial thromboembolic occlusion. Early recurrence and worsening
of left sided weakness prompted a catheter based angiographic study, identifying hyperacute thromboembolic occlusion at the
right carotid terminus. This was retrieved using combined local thromboaspiration and mechanical thombectomy preceded by
innominate artery angioplasty.
Findings: Axial contrast enhanced CTA of the head and neck; A: At the level of the supra-aortic branch vessels, occlusion of the
innominate artery (large solid arrow). Origin of the left vertebral artery from the aortic arch (dotted arrow). B: At the level of the
C1 vertebral body, marked diminution in caliber of the right internal carotid artery (solid arrow), relative to the left (dotted arrow).
C: At the level of the centrum semi ovale, increased cortical branch vessels on the right (solid arrow), relative to the left (dotted
arrow) compatible with pial collaterals.
Technique: Axial CT, 480mAs, 140kV, Slice thickness 0.63mm, 75 ml Isovue 370 injection at 4ml/second.

Figure 3: A 51-year-old male presented with acute transient left sided weakness. Chronic innominate artery steno-occlusive
disease was identified by initial CT angiography without intracranial thromboembolic occlusion. Early recurrence and worsening
of left sided weakness prompted a catheter based angiographic study, identifying hyperacute thromboembolic occlusion at the
right carotid terminus. This was retrieved using combined local thromboaspiration and mechanical thombectomy preceded by
innominate artery angioplasty.
Findings: A: Aortic arch angiography shows occlusion of the innominate artery (long arrow) and retrograde flow within the right
vertebral artery (short arrow). B: Aortic arch angiography demonstrates delayed retrograde distal innominate artery flow (dotted
arrow) and subsequent anti-grade flow into the right common carotid artery and internal carotid artery (long arrow) with distal
occlusion (double striped arrow). C: Angiography of the right common carotid artery (short arrow) after traversing the innominate
artery stenosis with a stiff guide wire shows absent flow within the intra cranial segment of the right internal carotid artery
compatible with carotid-T thromboembolic occlusion (long arrow).
Technique: A, B: Diagnostic 5French catheter injection of 30ml of Isovue 300 at 25cc/sec. C: Diagnostic 5F catheter injection of
6 of Isovue 300 at 4cc/sec.
Radiology Case. 2015 Mar; 9(3):27-36
32

www.RadiologyCases.com

Journal of Radiology Case Reports

Interventional
Radiology:

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

Gordhan et al.

Figure 4: A 51-year-old male presented with acute transient left sided weakness. Chronic innominate artery steno-occlusive
disease was identified by initial CT angiography without intracranial thromboembolic occlusion. Early recurrence and worsening
of left sided weakness prompted a catheter based angiographic study, identifying hyperacute thromboembolic occlusion at the
right carotid terminus. This was retrieved using combined local thromboaspiration and mechanical thombectomy preceded by
innominate artery angioplasty.
Findings: A: Fluoroscopic spot view shows an angioplasty balloon across the focal innominate artery stenosis (white arrow),
performed prior to mechanical and aspiration thrombectomy of the carotid terminus and right middle cerebra artery. B: Road map
image over the right frontal calvarium show the Solitaire stent retriever within the right middle cerebral artery (thin arrow) and the
position of the 054 Penumbra Reperfusion Catheter within the right internal carotid artery (thick arrow). C: DSA of the right
internal carotid artery with complete resolution of the carotid-T and right middle cerebral artery occlusion (arrows). D: Aortic arch
angiography in the left anterior oblique projection demonstrates residual stenosis at the innominate artery (thick arrow) and
revascularization of the right carotid and right anterior circulation with symmetric flow relative to the contra-lateral side (thin
arrow).
Technique: C: 054 Reperfusion Catheter (Penumbra Inc., Alameda, CA) catheter injection of 4ml of Isovue 300 at 4cc/sec for
right internal carotid artery digital subtraction angiography. D: Diagnostic 5 French catheter injection of 30ml of Isovue 300 at
25cc/sec for aortic arch digital subtraction angiography.

Radiology Case. 2015 Mar; 9(3):27-36

33

www.RadiologyCases.com

Journal of Radiology Case Reports

Interventional
Radiology:

Interventional
Radiology:

Etiology

Incidence

Gender Ratio
Age predilection
Risk factors
Treatment

Imaging Findings

Gordhan et al.

Atherosclerotic stenoocclusive disease of the IA is most common. Other causes of IA artery stenosis
includes traumatic injury, dissection, Takayasu arteritis, Thoracic mural thrombus syndrome (TMT),
Fibromuscular dysplasia, radiation induced arteriopathy, vasculitis and external compression from a
cervical rib.
IA atheromatous steno-occlusive disease has a reported incidence of 4%. A few case reports have
described thromboembolism to the carotid terminus and right middle cerebral artery. Extracranial
carotid artery disease accounts for 15-20% of all ischemic strokes, the majority as a result of carotid
bifurcation disease.
Not known for IA stenosis. Slight male preponderance for extracranial carotid bifurcation disease that
is often identified with innominate stenosis.
Mean age 62.
Risk factors for atherosclerotic disease that includes hypertension, diabetes, smoking, genetic
predisposition and sedentary life style.
Percutaneous transluminal angioplasty of the brachiocephalic vessels with or without stenting is a
viable alternative to surgery with lower peri-procedural complications. IV/IA tPA and endovascular
intervention for intracranial thromboembolism.
Carotid-T occlusions have a large clot burden with a dismal clinical outcome. Even after endovascular
recanalization, only 21.4% achieve functional independence.
Ultrasound:
Patient habitus and anatomy significantly effects assessment of the vertebral and subclavian arteries.
User dependent sensitivity and specificity. In subclavian steal or significant IA stenosis, altered VA
waveforms are seen only when the degree of stenosis is greater than 60%; permanent flow reversal
can be seen when a SA or IA stenosis is greater than 75%. Ultrasound can be helpful in determining
MCA occlusion; however this is not frequently performed.

www.RadiologyCases.com

Journal of Radiology Case Reports

Prognosis

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

MR Angiography:
3D gadolinium enhanced technique require shorter acquisition time, limiting motion artifact and is
useful for determining IA stenosis. 2D TOF technique provides information about the direction of
flow in the VA. If enhancement is present in a VA on gadolinium-enhanced MRA, but no
corresponding flow-related enhancement is seen on TOF MRA, then flow in that vessel must be
reversed. Occlusion of the ICA and or MCA can be easily determined.
CT Angiography:
CTA can show stenosis in the IA but does not evaluate VA flow reversal. Occlusion of the ICA and
or MCA can be easily determined. Chronic IA occlusion can be determined by extracranial carotid
artery caliber and right hemispheric pial collaterals.
CT and MR perfusion:
Cerebral blood flow, cerebral blood volume and mean transit time maps can identify hypoperfusion to
the right cerebral hemisphere with significant IA stenosis. These parameters can also be used to
determine a viable penumbra in the instance of carotid-T and or MCA occlusion.
Digital Subtraction angiography:
Reference standard for diagnosing and characterizing IA stenosis and steal phenomena. Provides
opportunity for endovascular intervention.

Table 1: Summary table for Innominate artery stenosis with thromboembolic Carotid-T occlusion.

Radiology Case. 2015 Mar; 9(3):27-36

34

Interventional
Radiology:

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

Gordhan et al.

Ultrasound
CT/CTA
MR/MRA
Other pertinent
 Useful in detecting a cervical rib  Postural narrowing of the  Postural narrowing of the  Radiographs of both
without ionizing radiation.
costoclavicular space with costoclavicular space with the cervical spine and
neurovascular
neurovascular
chest acquired to
 May also identify retrograde flow
compression at the
compression at the
identify bone
in the vertebral arteries and
thoracic outlet and
thoracic outlet and
abnormalities that
intraluminal thrombus.
identification of
identification of
may contribute
 Sonographic evaluation with
intraluminal thrombus.
intraluminal thrombus.
neurovascular
patient in an upright or seated
compression at the
position advantageous, as in
thoracic outlet. (e.g.
clinical examination for thoracic
cervical ribs,
outlet neurovascular compression,
elongated C7
in contrast to CT and MR imaging,
transverse process)
Innominate Artery  Transthoracic echocardiography
 Identification of a
 Identification of a
 Catheter angiography
Dissection
(TEE) for identification of a
dissection flap, mural
dissection flap, mural
is the gold standard
dissection of the innominate artery
thrombus, intraluminal
thrombus, intraluminal
for diagnosis and
limited by overlying ribs and
thrombus at the
thrombus at the
provides access for
tracheal shadowing.
innominate artery and
innominate artery and
endovascular therapy.
embolism within
embolism within
Indirect hemodynamic findings:
intracranial vasculature.
intracranial vasculature.
 Systolic deceleration or alternating  CTA has superior spatial
flow in the right vertebral artery
resolution than MRA
and only minor changes in the
carotid arteries.
 Reversed flow in the ipsilateral
vertebral artery and systolic
deceleration in the carotid arteries.
 Alternating flow or even complete
steal in the carotid arteries in
addition to vertebral artery steal.
 Decreased middle cerebral artery
blood flow velocity in
symptomatic supra-aortic vessel
dissection that is poorly
collateralized.
(Vasculitis)
 Homogenous circumferential
 Vessel wall thickening
 Vessel wall thickening
 Increased uptake in
Takayasu’ arteritis
thickening of affected vessels.
and enhancement in the
with increased T2 signal
thickened vessel wall
and Radiation
and enhancement in the
identified by PET
 Vascular occlusion with or without acute phase.
arteritis
acute phase.
(Positron Emission
dilatation.
 Diffuse vessel stenosis in
Tomography) in the
the late phase.
 Diffuse vessel stenosis in
 Elevated flow velocities distal to
acute phase.
the late phase.
stenotic segments.
 Distribution of vascular
changes localized to
 Distribution of vascular
radiation portal.
changes localized to
radiation portal.
Fibromuscular
 Segmental string-of-beads pattern  Segmental string-of-beads  Segmental string-of-beads  Catheter angiography
dysplasia
with alternating regions of lumen
pattern with alternating
pattern with alternating
is gold standard for
(FMD)
narrowing and vessel dilatation
regions of lumen
regions of lumen
diagnosis.
distal to a completely normal
narrowing and vessel
narrowing and vessel
segment of the vessel.
dilatation distal to a
dilatation distal to a
completely normal
completely normal
 Characterizes the hemodynamic
segment of the vessel.
segment of the vessel.
effect of associated stenosis.
Thoracic mural
 Transthoracic echocardiography  Aortic and or supra-aortic  Aortic and or supra-aortic  Increased risk of
thrombi syndrome
(TEE) for identification of focal thrombosis without focal thrombosis without thrombus
(TMT)
thrombus within the innominate underlying atherosclerotic underlying atherosclerotic embolization
with
artery limited by overlying ribs disease.
disease.
catheter angiography
and tracheal shadowing.
 Diagnostic modality of  Susceptible to greater
choice.
motion artifact than CTA.

Table 2: Differential diagnosis table for Innominate artery occlusion and Carotid-T thromboembolism.

Radiology Case. 2015 Mar; 9(3):27-36

35

www.RadiologyCases.com

Journal of Radiology Case Reports

External
compression
(Cervical rib)

Interventional
Radiology:

Chronic innominate artery occlusion with hyperacute intracranial thromboembolism:
Revascularization with simultaneous local thromboaspiration and mechanical thrombectomy

Gordhan et al.

CT = Computerized tomography
CTA = Computerized tomographic angiography
CAROTID-T = Carotid terminus
CCA = Common carotid artery
DSA = Digital subtraction angiography
EEG = Electroencephalography
FMD = Fibromuscular dysplasia
IA = Innominate artery
ICA = Internal carotid artery
IV = Intravenous
MCA = Middle cerebral artery
MRA = Magnetic resonance angiography
NIHSS = National Institute of Health Stroke Scale
SA = Subclavian artery
TEE = Transesophageal echocardiography
TOF = Time of flight
tPA = tissue plasminogen activator
VA = Vertebral artery

Online access
This publication is online available at:
www.radiologycases.com/index.php/radiologycases/article/view/1750

Peer discussion
Discuss this manuscript in our protected discussion forum at:
www.radiolopolis.com/forums/JRCR

Interactivity
This publication is available as an interactive article with
scroll, window/level, magnify and more features.
Available online at www.RadiologyCases.com

Published by EduRad

www.RadiologyCases.com

Journal of Radiology Case Reports

ABBREVIATIONS

KEYWORDS
Carotid-T thromboembolism; Innominate artery occlusion;
Middle cerebral artery thromboembolism; Thromboaspiration;
Mechanical thrombectomy

www.EduRad.org

ACKNOWLEDGEMENTS
Staff at St Joseph Medical Center

Radiology Case. 2015 Mar; 9(3):27-36

36