Images in Cardiovascular Medicine
Right Hemiparesis in Right Carotid Stenosis
P. Profice, MD; F. Pilato, MD; A. Broccolini, MD; A. Santoliquido, MD;
G. Della Marca, MD; V. Di Lazzaro, MD

A

He arrived at the emergency department 6 days after the
onset of symptoms. On neurological examination, the
patient showed mild disorientation both in time and in
place; no other neurological signs could be elicited. Blood
pressure was 160/90 mm Hg. Blood count, prothrombin
time, activated thromboplastin time, ionogram, C-reactive

72-year-old right-handed man with a history of
hypertension and past smoking, taking low-dose aspirin therapy (100 mg once a day) for cardiovascular
prevention, presented with sudden onset of right hemiparesis and confusion. The right hemiparesis improved during the following days, but the patient was still confused.

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Figure 1. Ultrasound (2-dimensional) images of left (A) and right (C) internal carotid arteries (ICAs) and Doppler waveforms of left
(B) and right (D) ICAs showing severe stenosis and increased peak systolic velocity (513 cm/s) of the left ICA and normal peak
systolic velocity (65.3 cm/s) of the right ICA.

From the Institute of Neurology (P.P., F.P., A.B., G.D.M., V.D.L.) and Department of Internal Medicine (A.S.), Università Cattolica, Rome, Italy; and
Department of Neuroscience, AFaR-Fatebenefratelli Association for Biomedical Research, “San Giovanni Calibita-Fatebenefratelli” Hospital, Isola
Tiberina, Rome, Italy (V.D.L.).
Correspondence to Vincenzo Di Lazzaro, Istituto di Neurologia, Università Cattolica, L.go A. Gemelli 8, 00168 Rome, Italy. E-mail
vdilazzaro@rm.unicatt.it
(Circulation. 2011;124:360-362.)
© 2011 American Heart Association, Inc.
Circulation is available at http://circ.ahajournals.org

DOI: 10.1161/CIRCULATIONAHA.110.991372

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Profice et al

Right Hemiparesis in Right Carotid Stenosis

361

Figure 2. Diffusion-weighted magnetic resonance
imaging showing acute watershed infarcts in right
(A) and left (B) hemispheres.

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protein, troponin Ic, and creatine kinase were normal. ECG
revealed normal sinus rhythm (76 bpm). Extracranial
carotid and vertebral arteries eco-color-doppler showed
⬎80% stenosis of the proximal right internal carotid artery
(ICA) and no significant stenosis of the left ICA (Figure 1A
through D). Diffusion-weighted magnetic resonance imaging
of the brain showed bilateral acute border-zone ischemic
lesions suggesting watershed infarcts (Figure 2A and B).
Magnetic resonance time-of-flight angiogram of intracranial
arteries showed agenesis of left A1 segment of the anterior
cerebral artery (Figure 3A), with left A2 segment arising from
the anterior communicating artery. Contrast-enhanced magnetic resonance angiogram of the neck confirms the right ICA
stenosis (Figure 3B). The patient was treated with clopidogrel
and atorvastatin and underwent right ICA endoartherectomy
successfully after 15 days.

Discussion
Knowledge of the presence and clinical relevance of
variation of circle of Willis plays a crucial role in the
diagnosis and management of acute stroke. The neurological symptoms can be influenced by changes in normal
brain-vessel anatomy. Anatomic variation of circle of

Willis is not uncommon: It has been reported that only
42% of subjects showed a complete circle of Willis on
magnetic resonance angiogram.1
It has been reported in magnetic resonance angiogram
studies that the A1 segment can be absent in ⬎5% of
subjects,1 and it has been suggested that this condition can
be a significant predisposing factor for bilateral anterior
cerebral artery territory infarction.2,3 In this patient, right
carotid is the principal supplier of left anterior cerebral
artery because of aplasia of the left A1 segment. The right
carotid stenosis was therefore very likely responsible for
bilateral border-zone infarcts. The clinical symptoms and
the neuroradiological picture demonstrated that brain ischemia was more pronounced in the left hemisphere,
which can be considered the extreme border zone of the
right carotid. The pathogenesis of watershed infarction is
still debated; both the hemodynamic and the embolic
mechanisms can be involved.4 In our case, the bilateral
border-zone infarcts seem to suggest a hemodynamic
pathogenesis secondary to severe carotid stenosis. Intracranial vascular imaging should be considered in stroke
patients, not only for investigating intracranial stenosis,
but also for evaluating variations of circle of Willis that
can influence stroke pathophysiology.

Figure 3. A, Contrast-enhanced magnetic
resonance angiogram of the neck: Arrow
shows narrowing of proximal ICA. B,
Time-of-flight magnetic resonance angiogram: Arrow shows agenesis of left A1
segment.

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Circulation

July 19, 2011

Disclosures
None.

References
1. Krabbe-Hartkamp MJ, van der Grond J, de Leeuw FE, de Groot JC,
Algra A, Hillen B. Circle of Willis: morphologic variation on threedimensional time-of-flight MR angiograms. Radiology. 1998;207:
103–111.

2. Yamaguchi K, Uchino A, Sawada A, Takase Y, Kuroda Y, Kudo S.
Bilateral anterior cerebral artery territory infarction associated with unilateral hypoplasia of the A1 segment: report of two cases. Radiat Med.
2004;22:422– 425.
3. Chuang YM, Liu CY, Pan PJ, Lin CP. Anterior cerebral artery A1
segment hypoplasia may contribute to A1 hypoplasia syndrome. Eur
Neurol. 2007;57:208 –211.
4. Momjian-Mayor I, Baron JC. The pathophysiology of watershed
infarction in internal carotid artery disease: review of cerebral perfusion
studies. Stroke. 2005;36:567–577.

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