Neurol Med Chir (Tokyo) 45, 97¿99, 2005

Occlusion of the Vertebral Artery Secondary to
Dissection of the Subclavian Artery
—Case Report—
Yasushi IWAMURO, Ichiro NAKAHARA, Masato TANAKA, Toshio HIGASHI,
Yoshihiko WATANABE, Kei HARADA, Motoaki FUJIMOTO, and Takayuki OKU
Department of Neurosurgery, Kokura Memorial Hospital, Kitakyushu, Fukuoka

Abstract
A 34-year-old man presented with occlusion of the left vertebral artery (VA) secondary to dissection of
the left subclavian artery manifesting as vertigo, nausea, vomiting, and neck pain. On admission, he
was alert with left limb and truncal ataxia. Magnetic resonance (MR) imaging and MR angiography
showed left cerebellar infarction and occlusion of the left VA. Conventional angiography and threedimensional computed tomography (3D-CT) angiography showed stenosis with thrombosed pseudolumen of the left subclavian artery, and occlusion of the left VA. Presumably the idiopathic dissection
of the left subclavian artery had reached the orifice of the left VA, and an embolism from the dissection
had caused occlusion of the VA, leading to cerebellar infarction. After one month, he was discharged
without severe neurological deficits. Idiopathic dissection of the subclavian artery is very rare. 3D-CT
angiography is very useful for the diagnosis of arterial dissection.
Key words: cerebellar infarction, subclavian artery,
three-dimensional computed tomography angiography

Introduction

neck pain while sleeping on April 16, 2003. He
observed the course of the symptoms during the
night, and the symptoms improved slightly. He
consulted a local doctor 3 days after the onset.
Magnetic resonance (MR) imaging identified cerebellar infarction. He was then referred to our institute.
On admission, he was alert and complained of
neck pain, left limb ataxia, and hemi-numbness on
the left side as sequelae of the previous cerebral
infarction. His blood pressure was 206/125 mmHg.
Family medical history was not contributory.
Laboratory testing on admission showed that
protein-C, protein-S, anti-cardiolipin antibody,
lupus circular coagulant, c-antineutrophil cytoplasmic antibody (ANCA), p-ANCA, anti-thrombin III,
supplement body, and crioglobulin levels, and blood
sedimentation rate were all within the normal limits.
Initial MR imaging in our hospital depicted an old
lesion in the right basal ganglia and a fresh lesion in
the left cerebellum (Fig. 1), and MR angiography
identified occlusion of the left VA (Fig. 2). The
initial diagnosis was dissection of the left VA.
Anti-platelet therapy and blood pressure reducing
therapy were begun. Angiography depicted stenosis

Subclavian artery dissection is usually caused by
trauma,4,7) for example, seat belt injury during traffic accidents,4,7) sports injury such as swinging a
golf club,5) iatrogenic injury during catheterization
or angioplasty,1) or following aortic dissection with
or without Marfan's syndrome.8) The typical initial
clinical symptoms are subclavian steal syndrome,6)
ischemic symptoms caused by embolism from the
dissection or the dissection reaching the orifice of
the vertebral artery (VA),5) and a difference in blood
pressure between the right and left arms.2) We
describe a case of idiopathic dissection of the subclavian artery manifesting as cerebellar infarction,
which was depicted clearly by three-dimensional
computed tomography (3D-CT) angiography.

Case Report
A 34-year-old man, with a history of cerebral infarction and untreated hypertension 3years previously,
suddenly developed vertigo, nausea, vomiting, and
Received

January 5, 2004;

Accepted

dissection,

August 9, 2004

97

Y. Iwamuro et al.

98

Fig. 1

T2-weighted magnetic resonance images on
admission demonstrating infarction (arrow)
in the left cerebellum.

Fig. 2

Magnetic resonance angiogram on admission demonstrating occlusion of the left
vertebral artery.

of the proximal portion of the left subclavian artery
and occlusion of the left VA, which were not visible
on the angiogram performed at the time of the
previous cerebral infarction (Fig. 3), and right
vertebral arteriography depicted the stump of the
distal portion of the left VA (Fig. 4). 3D-CT
angiography showed the stenotic portion of the
subclavian artery consisted of thrombosed pseudolumen caused by dissection of the subclavian
artery (Fig. 5). Based on these findings, the diagnosis
was idiopathic dissection of the left subclavian
artery extending to the orifice of the left VA, and
embolism from the dissection causing occlusion of
the left VA, resulting in cerebellar infarction. One
month after the stroke, he was discharged with
numbness on the left.

Fig. 3

Left subclavian angiograms showing stenosis of the proximal portion of the left subclavian artery (arrow) and occlusion of the
left vertebral artery (right) not visible at the
time of the previous cerebral infarction
(left).

Fig. 4

Right vertebral arteriograms showing the
stump of the distal portion of the left
vertebral artery.

Fig. 5

Three-dimensional computed tomography
angiograms showing that the stenotic
portion of the subclavian artery consisted of
thrombosed pseudolumen caused by dissection of the subclavian artery (arrow).

Discussion
Our patient had no systemic disease or history of
trauma, so this case is thought to be idiopathic

subclavian artery dissection. The mechanism causing aortic dissection is thought to involve the angle
between the ascending and descending aorta,

Neurol Med Chir (Tokyo) 45, February, 2005

Dissection of Subclavian Artery
because the abrupt change in direction of blood flow
may cause damage to the aortic wall.8) A higher
incidence of arterial dissection is associated with
left VA of aortic origin, compared to left VA of left
subclavian artery origin or right VA of right subclavian artery origin, suggesting that the incidence of
dissection is related to direct arterial pulsatile flow.3)
The left subclavian artery is thought to receive stronger pulsatile flow than the right subclavian artery.
In our case, we think that the left subclavian
artery received more severe stress because of his
hypertension.
The typical initial clinical symptoms are due to
reduced blood flow in the subclavian artery and
embolism from the dissection or the dissection
reaching the orifice of the VA. In our case, right
vertebral arteriography showed only the stump of
the left VA. Therefore, occlusion of the left VA was
probably caused by emboli from the dissection of the
subclavian artery or VA. Our patient presented with
vertigo due to embolic infarction of the cerebellum,
but the symptom was mild and atypical. The stenosis
of the subclavian artery at the dissection was not
severe. Therefore, the dissection was probably not
the direct cause of the symptom. The neck pain may
have been caused by dissection of the orifice of the
VA.
The only angiographic finding indicating
dissection in our case was the stenosis, which was
not visible on the angiogram performed at the time
of the pervious cerebral infarction. No double
lumen, pooling, slow filling, or intimal flap were
detected. We think that idiopathic dissection of the
subclavian artery occurs more often than is
believed, and should be included in the differential
diagnosis. In our case, 3D-CT angiography clearly
showed the double lumen and wall irregularity,
strongly suggesting dissection. We consider that
3D-CT angiography is useful for the identification of
dissection because the thrombosed pseudo-lumen of
the dissection can be visualized.

Neurol Med Chir (Tokyo) 45, February, 2005

99

References
1)

2)

3)

4)

5)

6)

7)

8)

Frohwein S, Ververis JJ, Marshall JJ: Subclavian artery
dissection during diagnostic cardiac catheterization:
The role of conservative management. Cathet
Cardiovasc Diagn 34: 313–317, 1995
Kobayashi E, Shimazaki K, Shimoeda N, Hirai N,
Yamaura A: [Stenting for dissection of the subclavian
artery after balloon angioplasty: a case report]. No
Shinkei Geka 27: 365–369, 1999 (Jpn, with Eng
abstract)
Komiyama M, Morikawa T, Nakajima H, Nishikawa
M, Yasui T: High incidence of arterial dissection
associated with left vertebral artery of aortic origin.
Neurol Med Chir (Tokyo) 41: 8–12, 2001
Myers SI, Harward TR, Cagle L: Isolated subclavian
artery dissection after blunt trauma. Surgery 109:
336–338, 1991
Scheffler P, Uder M, Gross J, Pindur G: Dissection of
the proximal subclavian artery with consecutive
thrombosis and embolic occlusion of the hand arteries
after playing golf. Am J Sports Med 31: 137–140, 2003
Schmitter SP, Marx M, Bernstein R, Wack J, Semba
CP, Dake MD: Angioplasty-induced subclavian artery
dissection in a patient with internal mammary artery
graft: treatment with endovascular stent and stentgraft. AJR Am J Roentgenol 165: 449–451, 1995
Thussu A, Srivastava T, Singh P: Traumatic dissection
of extracranial internal carotid artery and subclavian
artery. Australas Radiol 43: 358–359, 1999
Yoshii S, Kamiya K, Matsukawa T, Ueno A: [3D
analysis of the aortic arch aneurysm: importance of
the transverse arch curve from the horizontal view].
Nippon Geka Gakkai Zasshi 89: 972, 1988 (Jpn)

Address reprint requests to: Y. Iwamuro, M.D.,
Department of Neurosurgery, Kokura Memorial
Hospital,
1–1
Kifune–machi,
Kokurakita–ku,
Kitakyushu, Fukuoka 802–8555, Japan.
e-mail: yiwamuro＠tc4.so-net.ne.jp