Reminder of important clinical lesson

Bilateral common carotid artery dissection
Ryota Inokuchi,1 Hajime Sato,2 Yuta Aoki,1 Naoki Yahagi1
1

Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan
Department of Health Policy and Technology Assessment, National Institute of Public Health, Wako, Saitama, Japan

2

Correspondence to Dr Ryota Inokuchi, inokuchir-icu@h.u-tokyo.ac.jp

Summary
A 63-year-old Japanese man with no significant medical or family history was admitted for sudden consciousness disturbance, left
hemiparesis and shock. Physical examination showed internal carotid artery asymmetry on palpation and significant differential blood
pressure in both upper arms. A thoracic CT scan showed classic aortic dissection from the ascending aorta through the common iliac
artery, classic dissection of the left common carotid artery and an intramural haematoma in the right common carotid artery. The patient’s
consciousness level gradually improved, and he underwent emergency surgery involving aortic rebuilding with a synthetic graft.
Subsequently, he had a good clinical course.

BACKGROUND
Dissection of the common carotid artery is frequently
associated with aortic dissection. Bilateral carotid artery
dissections are rare and have unknown prevalence; in addition, they may cause hemiplegia and altered mental
status, thereby hindering their early diagnosis.

CASE PRESENTATION
A 63-year-old man with no significant medical and family
history was admitted to the emergency room for sudden
consciousness disturbance and left hemiparesis. On admission to the emergency department, his body temperature
was 36.4°C; pulse rate, 82 beats/min; blood pressure, 110/
60 and 65/31 mm Hg for the right and left arms, respectively; and the Glasgow Coma Scale score was 4/15 (eyes,
1; verbal, 1; and motor, 2). On examination, internal
carotid artery asymmetry was evident on palpation.
Further clinical examination showed isolated twitching of
the right arm and incontinence. Heart murmur, chest
rales and tongue biting were absent.

INVESTIGATIONS
Thoracoabdominal contrast CT showed classic aortic dissection from the ascending aorta through the common

iliac artery (figure 1A), classic dissection of the left
common carotid artery and an intramural haematoma in
the right common carotid artery (figure 1B). The patient’s
consciousness level gradually improved over 30 min; he
experienced anterior chest and back pain but not paralysis.
He underwent emergency surgery involving aortic rebuilding with a synthetic graft and had a good clinical course.
On day 21, the patient was discharged without
complications.

DISCUSSION
Aortic dissection can occur by two possible mechanisms1
(figure 2). The classic mechanism is an intimal tear,
which is usually transverse and extends through the very
thin tunica intima into the tunica media. Blood enters a
layer of the media under pulsatile pressure, resulting in
longitudinal dissection, usually in a distal direction. The
other major mechanism is rupture of the vasa vasorum,
usually of a penetrating branch within the tunica media,
with consequent bleeding into the media. Progression
then occurs in the same fashion, either with or without
secondary tearing through the intima into the aortic
lumen. The aorta usually tears near tethering points,
where the vessel undergoes the greatest flexion stress

Figure 1 (A) Axial image through the thorax shows the initial dissection flap in the aortic arch (arrowhead). (B) Classic dissection of
the left common carotid artery (arrow) was seen together with an intramural haematoma in the right common carotid artery (arrowhead).
T, true lumen; F, false lumen; I, intramural haematoma.
BMJ Case Reports 2012; doi:10.1136/bcr-2012-006207

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Figure 2 Two mechanisms for aortic dissection. A, adventitia; I, intima; M, media.

during cardiac contractions. Thus, the most common location of dissection initiation is the first few centimetres of
the ascending aorta, with the next most common being
the origin of the descending aorta, just distal to the left
subclavian artery.2
Dissection of the common carotid artery is frequently
associated with aortic dissection,3 but bilateral carotid
artery dissections are rare and have unknown prevalence.4
Syncope occurs early in aortic dissection in approximately
9% of cases and may be the sole presentation in some
patients.5 6 It most often heralds dissection into the pericardium, causing pericardial tamponade, but may occur
because of transient interruption of blood flow to the
cerebral vasculature, as in our case. Neurological symptoms such as focal weakness or mental status changes
occur in up to 17% of cases.5–7 Overlooking aortic dissection during thrombolytic therapy for patients with acute
stroke leads to poor outcomes.
Routine laboratory tests are of little value in diagnosing
aortic dissection; recently, however, there has been increasing interest in the biochemical diagnosis of acute aortic
dissection.8 Myosin heavy-chain concentrations, D-dimer
levels9 and soluble elastin fragment concentrations are
some of the newer tools that may help diagnose aortic
dissection. Prospective clinical trials to evaluate their usefulness are pending. A recent meta-analysis found that
D-dimer level assessment exhibited 97% sensitivity for
aortic dissection.10 However, that assessment requires
careful attention, because D-dimer levels also increase in
cases of disseminated intravascular coagulation, deep vein
thrombosis, pulmonary emboli, cancer, myocardial infarction, pregnancy and sepsis.11 12
In conclusion, early identification and management of
dissection as a cause of ischaemic stroke is important
while treating patients in shock.

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Learning points
▸ The aggressiveness of screening for aortic dissection in
patients who are in shock and exhibit neurological
abnormalities should be further evaluated.
▸ D-dimer-level assessment has 97% sensitivity for aortic
dissection.
▸ Dissection of the common carotid artery is frequently
associated with aortic dissection, but bilateral carotid
artery dissections are rare.

Competing interests None.
Patient consent Obtained.

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BMJ Case Reports 2012; doi:10.1136/bcr-2012-006207

9. Eggebrecht H, Naber CK, Bruch C, et al. Value of plasma fibrin D-dimers for
detection of acute aortic dissection. J Am Coll Cardiol 2004;44:804–9.
10. Shimony A, Filion KB, Mottillo S, et al. Meta-analysis of usefulness of d-dimer
to diagnose acute aortic dissection. Am J Cardiol 2011;107:1227–34.

11. Adam SS, Key NS, Greenberg CS. D-dimer antigen: current concepts and
future prospects. Blood 2009;113:2878–7.
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Emerg Med 2009;27:1016.e5–7.

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