Rare disease

Case report

Pure posterior communicating artery occlusion
treated with mechanical thrombectomy
Ryosuke Otsuji, Katsuharu Kameda, Junji Uno, Hidefuku Gi
Department of Neurosurgery,
Baba Memorial Hospital, Sakai,
Osaka, Japan
Correspondence to
Dr Ryosuke Otsuji,
​ryosuke022@​gmail.​com
Accepted 5 May 2017

Summary
There has been no report of mechanical thrombectomy
for a pure posterior communicating artery (PComA)
occlusion. Here, we report the case of an 87-year-old
woman with a disturbance of consciousness and left
hemiparesis diagnosed with a right PComA occlusion.
The patient was successfully treated using mechanical
thrombectomy in combination with a stent retriever
and the Penumbra system. A CT perfusion image
showed cerebral blood flow reduction in the ipsilateral
occipital lobe and thalamus. A CT angiography
supported the diagnosis of an occlusion of fetal type
PComA. The PComA could not be detected by internal
carotidangiogram, but after deployment of stent retriever,
the PComA was recanalised and distal embolus at
the right posterior cerebral artery was visualised. The
thrombus was then removed using the Penumbra system.
Although the treatment for a PComA occlusion requires
further investigation, the present case supports a
thrombectomy as an effective rescue strategy for PComA
occlusions.

Background
There has been no report of mechanical thrombectomy for a pure posterior communicating
artery (PComA) occlusion. In total, 250 consecutive patients with acute ischaemic stroke have been
treated with mechanical thrombectomy at our
hospital; however, only one case involved a pure
PComA occlusion.
The PComA connects the carotid and the posterior cerebral arteries. Owing to a low-pressure
gradient between the two systems, pure PComA
occlusion is rare.1 Mechanical thrombectomy for
pure PComA occlusion requires further discussion because of its rare frequency. Here, we report
the case of pure PComA occlusion treated with
mechanical thrombectomy.

Case presentation

To cite: Otsuji R, Kameda K,
Uno J, et al. BMJ Case
Rep Published Online First:
[please include Day Month
Year]. doi:10.1136/bcr-2017219589

An 87-year-old woman was admitted to an emergency room of our hospital owing to impaired
consciousness (Glasgow Coma Scale 13) and left
hemiparesis. A National Institute of Health Stroke
Scale score of 13 recorded on admission. The patient
had no medical or family history to be noted.

Investigations
A CT scan showed no intracranial haemorrhage or
early ischaemic signs. CT perfusion showed cerebral blood flow (CBF) reduction, mean transit time

(MTT) elongation at the right occipital lobe, mild
CBF reduction and mild MTT elongation at the
middle cerebral artery area (figure 1). However, a
three-dimensional CT angiography (CTA) showed
mild intracranial stenosis at the right internal
carotid artery (ICA) without a deficit of the right
posterior cerebral artery (PCA) (figure 2A, C). A
CTA source image (CTA-SI) revealed an occlusion
of the right fetal-type PComA (figure 2B, D).

Treatment
After intravenous injection of recombinant tissue
plasminogen activator, endovascular treatment
was provided after obtaining informed consent of
the family of the patient in conformance with the
policy of the Ethical Review Board of our hospital.
Left vertebral angiogram showed bilateral hypoplastic PCA (P1) (figure 3A). Although, the PCA was
depicted as a peripheral artery on CT, the flow of
the contrasting agent was delayed. Internal carotid
(IC) angiogram of the right showed a 4 mm long
mural thrombus at the IC-PComA bifurcation
portion. (figure 3B). PComA and PCA were not
delineated through IC angiography. Based on these
findings and the CT perfusion data, we diagnosed
the patient with an acute pure PComA occlusion on
the right.
A stent retriever was applied to remove the
mural thrombus because we could not identify the
PComA after the angiogram. We deployed Solitaire
FR (Medtronic, Minneapolis, Minnesota, USA)
6 mm/30 mm at the mural thrombus site. At 2.5 min
after stent deployment, an IC angiogram revealed
the PComA recanalisation and distal embolus at the
right PCA (figure 3C and D), which was retrieved
using two passes of 5MAX ACE (Penumbra,
Alabama, California, USA) with A Direct Aspiration
First Pass Technique (figure 3E). The distal PCA
(P4) occlusion remained; therefore, the final recanalisation rate was equivalent to thrombolysis in
cerebral infarction grade 2b. The time from onset
to reperfusion was 319 min.

Outcome and follow-up
The patient fully recovered from left hemiparesis
and impaired consciousness within 24 hours after
reperfusion therapy. Diffusion-weighted MRI
revealed multifocal punctate infarction in the right
thalamus and occipital lobe (figure 4). The modified Rankin Scale score of the patient at 90 days
was 3 because of vascular dementia before admission.

Otsuji R, et al. BMJ Case Rep 2017. doi:10.1136/bcr-2017-219589

1

Rare disease

Figure 1 Four slices of a head CT perfusion image on admission are
shown. Cerebral blood flow, cerebral blood volume and mean transit
time are shown in order from the left. A CT angiography source image
of the arterial phase is shown on the right side. On the thalamus and
posterior cerebral artery region, a reduction of cerebral blood flow and
an extension of the mean transit time are shown on the ipsilateral side.
In contrast, the cerebral blood volume is reserved compared with the
contralateral side. P, posterior side; R, right side.

Discussion

In the present case, although P1 was hypoplastic with fetal-type
PComA (FTP), PCA was depicted through P1 owing to occlusion
of PComA. Thus, the CTA findings of posterior circulation of the

Figure 2 A three-dimensional CT angiography shows the posterior
communicating artery occlusion (A, C: reconstructed image; B, D: axial
image). The right posterior cerebral artery (P2; black arrowhead) is
well depicted through the low forming right posterior cerebral artery
(P1; black arrow) (A, B). In the reconstructed image, the right posterior
communicating artery is not drawn (A), and the stenosis is shown at
the supraclinoid portion of internal carotid artery (C; white arrow head).
A defect of the contrast agent is seen at the internal carotid artery
through the full length of the posterior communicating artery (D; white
arrow).
2

Figure 3 Angiographic findings are shown that were observed during
interventional radiology. (A) A left vertebral angiogram shows the
right posterior cerebral artery (P2) through the hypoplastic posterior
cerebral artery (P1); there was a delay in depicting P2. (B) The posterior
communicating artery and posterior cerebral artery are not drawn in
the right internal carotid angiogram. Mural thrombus of 4 mm in length
is observed at the IC-PComA bifurcation (white arrow). (C) A rendering
of the posterior communicating artery was obtained when the stent
retriever was expanded (*). (D) A migrated thrombus in late phase is
shown via the posterior communicating artery. (E) After removal of
the thrombus, the posterior communicating artery and the hypoplastic
posterior cerebral artery were reperfused (thrombolysis in cerebral
infarction grade 2b).
present case resembled that of a normal case; therefore, the diagnosis of a pure PComA occlusion was difficult. We could diagnose
based on CT perfusion image with CBF decreased in the PCA
territory, CTA findings of obviously hypoplastic P1 compared with
periphery of PCA and CTA-SI with a contrast agent defect of on
PComA.
Although the ischaemic area was detected in the right occipital lobe, the patient’s symptoms were severe. We had no direct
evidence that a pure PComA occlusion on the non-dominant
hemisphere impaired consciousness and caused the left hemiparesis; however, we believe that the patient’s symptoms were due
to a PComA occlusion because of the sudden onset of symptoms,
the clinical course, symptom improvement after recanalisation
and no symptom recurrence during the observation period. An
occlusion of the tuberothalamic artery (TTA) originates from the
middle third of the PComA and causes acute severe perseverative
behaviour that is apparent in cognition, speech and all memory-related and executive tasks, in combination with increased sensitivity to interference.2 Similar to the present case, a previous study
reported contralateral paresis in a patient with a TTA infarction

Figure 4 Diffusion-weighted MRI of the patient after mechanical
thrombectomy. A small infarction was observed in the right thalamus
(A, B) and occipital lobe (C). No infarction appeared in the anterior
circulation (A, B, C).
Otsuji R, et al. BMJ Case Rep 2017. doi:10.1136/bcr-2017-219589

Rare disease
due to occlusion of the PComA after coil embolisation for an
IC-PComA aneurysm.3 4
Mechanical thrombectomy has been shown to be effective for
acute ischaemic stroke;5 however, a thrombectomy for an acute
occlusion of the PComA has not been established. The average
diameter of the PComA is reported to be 1.3 mm (0.3–3.1 mm).6
We use the Penumbra system in the present case. The diameter of
the PComA in the present case was 2.00 mm and the Penumbra
system (with a 0.060 inch (1.524 mm) calibre) could be easily
applied, and fortunately after the reperfusion, consciousness
improved and hemiparesis was alleviated. A previous study
reported that for the anterior circulation, Penumbra and Stent
treatment groups show no differences in efficacies and complications of mechanical thrombectomy.7 Regarding the present case,
we believe that the thrombus initially occluded the IC-PComA
bifurcation and then migrated to the PComA, which had a
relatively larger vessel diameter. We assumed that the mural
thrombus of the ICA was proximal edge of thrombus of PComA,
and the thrombus occluded ICA at IC-PComA bifurcation.
Therefore, we attempted a recovery of flow of PComA using a

Learning points
►► We present the first case of pure posterior communicating

artery (PComA) occlusion treated with mechanical
thrombectomy.
►► Cautious evaluation of the CT perfusion image, CT
angiography and angiograms enables to diagnose the
PComA occlusion.
►► Mechanical thrombectomy with A Direct Aspiration First Pass
Technique or stent retriever was feasible and effective to
treat to PComA occlusion.

stent retriever by deploying Solitaire to ICA, because fortunately,
we could identify the origin of PComA and made it possible to
continue thrombectomy. Had we been unable to identify the
origin of the PComA, further treatment would have been difficult.
Although further investigations on appropriate treatment
strategies for PComA occlusion are required, the present case
indicates the use of thrombectomy as an effective rescue strategy
in the treatment of PComA occlusions in acute ischaemic stroke.
Contributors RO and KK: data gathering and manuscript preparation. KK and JU:
review, editing and study design. HG: guarantor and overall review.
Competing interests None declared.
Patient consent Consent obtained from next of kin.
Provenance and peer review Not commissioned; externally peer reviewed.
© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article)
2017. All rights reserved. No commercial use is permitted unless otherwise expressly
granted.

References

1 Yang JH, Choi HY, Nam HS, et al. Mechanism of infarction involving ipsilateral carotid
and posterior cerebral artery territories. Cerebrovasc Dis 2007;24:445–51.
2 Ghika-Schmid F, Bogousslavsky J. The acute behavioral syndrome of anterior thalamic
infarction: a prospective study of 12 cases. Ann Neurol 2000;48:220–7.
3	Endo H, Sato K, Kondo R, et al. Tuberothalamic artery infarctions following coil
embolization of ruptured posterior communicating artery aneurysms with posterior
communicating artery sacrifice. AJNR Am J Neuroradiol 2012;33:500–6.
4 Lee KD, Kwon SC, Muniandy S, et al. Tuberothalamic artery infarction following coil
embolization of a ruptured posterior communicating artery aneurysm belonging
to a transitional type posterior cerebral artery. A case report. Interv Neuroradiol
2013;19:306–12.
5 Muir KW, White P. HERMES: messenger for stroke interventional treatment. Lancet
2016;387:1695–7.
6	Saeki N, Rhoton AL. Microsurgical anatomy of the upper basilar artery and the
posterior circle of Willis. J Neurosurg 1977;46:563–78.
7 Lapergue B, Blanc R, Guedin P, et al. A direct aspiration, first pass technique (ADAPT)
versus stent retrievers for acute stroke therapy: An observational comparative study.
AJNR Am J Neuroradiol 2016:1860–5.

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Otsuji R, et al. BMJ Case Rep 2017. doi:10.1136/bcr-2017-219589

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