Key-words:
Acute ischemic stroke - endovascular treatment - microguidewire - modified pigtail-shape
- thrombectomy
Introduction
Mechanical thrombectomy for acute ischemic stroke has been widely used since its efficacy
was proved.[[1]] During the procedure, a physician guides the microcatheter into invisible vessels
on fluoroscopy. To date, we use modified pigtail-shape microguidewires (MPMGWs) for
thrombectomy as reported by Sato et al.[[2]] MPMGW provides better vessel selectivity with torque and better microcatheter trackability
due to working as an anchor compared to devices with a rectal-angled shape. Moreover,
Ohshima et al.[[3]],[[4]] reported that it provides information about the quality of the clot during clot
penetration, and enables effective penetration of an extremely hard clot via the corkscrew
penetrating method. In our case, it was difficult to determine the origin of the occluded
artery or unruptured aneurysm during the procedure. MPMGW had an important role in
making this difficult judgment. We thought that this case is unique and important
to prevent catastrophic complications.
Case Report
A 75-year-old man was admitted to our emergency department with right-sided hemiplegia
and aphasia 40 min after initial presentation. At admission, his National Institute
of Health Stroke Scale score was 13.[[5]] The 12-lead electrocardiogram revealed atrial fibrillation. Emergency diffusion-weighted
imaging demonstrated a high-intensity area in the left insular gyrus. Magnetic resonance
angiography showed left middle cerebral artery occlusion [[Figure 1]]. The Alberta Stroke Program Early Computed Tomography (CT) Score was 9.[[6]] Intravenous recombinant tissue plasminogen activator (rt-PA) injection was initiated
35 min after his arrival. He was transferred into the angio-room for endovascular
thrombectomy without confirming the efficacy of the rt-PA.
Figure 1: Initial magnetic resonance angiography shows disappearance of the M1 segment of the
left middle cerebral artery (arrow) R: Right
Under local anesthesia, a 9-F Optimo balloon guide catheter (Tokai Medical Products,
Aichi, Japan) was advanced into the left internal carotid artery through the right
common femoral artery. Because left carotid angiogram revealed partial occlusion of
the middle cerebral artery with a shadow of the clot [[Figure 2]], we diagnosed as an embolism rather than a chronic stenosis. We attempt to recanalize
through the Stent-Retrieving into an Aspiration Catheter with Proximal Balloon method.[[7]] A Penumbra ACE 68 aspiration catheter (Medicos-Hirata, Osaka, Japan), Marksman
microcatheter (Medtronic, Minneapolis, MN, USA), and a Chikai 14 microguidewire (Asahi
Intecc Co. Ltd., Aichi, Japan) were coaxially navigated. The wire tip was shaped using
the attached shaping mandrel as the modified pigtail shape. The round tip was approximately
2 mm in diameter [[Figure 3]]. After a Revive SE Thrombectomy Device (Codman, Raynham, MA, USA) was deployed
and retrieved, the clot shadow totally disappeared. However, a bulge, which did not
distinguish the origin of the artery or an unruptured aneurysm, was found [[Figure 4]]a. A lateral view of the left carotid angiogram revealed a nonvasculized area [[Figure 4]]b. Therefore, the Penumbra ACE 68, Marksman microcatheter, and Chikai 14 guidewire
were advanced again. The round tip of the guidewire was navigated carefully into the
bulge. We believed if there was an occlusion due to clot formation, the round tip
of the wire could be advanced while maintaining the shape. The wire tip was pushed
into the bulge, and the patient showed unusual body movement. The road-mapping image
suddenly deviated because of the patient's movement [[Figure 5]]. Because we judged that the patient felt pain due to stimulating the aneurysm by
the wire, we decided to withdraw from the procedure.
Figure 2: The left carotid angiography shows a partial occlusion of the middle cerebral artery
with a shadow of the clot (arrow). R: Right
Figure 3: Photographs of the modified pigtail-shaped microguidewire
Figure 4: Angiographies after stent retrieval. (a) Anterior-posterior view; A white arrow indicates
a small bulging. R: Right. (b) Lateral view; White arrowheads indicate nonvascularized
area. P: Posterior
Figure 5: Intraprocedural road-mapping Images. (a) Right before the wire navigates into the
bulging. A white arrow indicates a small bulging. (b) After the wire insertion into
the bulging. The road-mapping image is deviated due to the patient's abnormal movement.
R: Right
Subsequent three-dimensional angiography demonstrated that the bulge was a small aneurysm
and a recanalized branch appeared just beside it [[Figure 6]]a. Finally, complete spontaneous recanalization was achieved [[Figure 6]]b. Postprocedural brain CT revealed neither intracranial hemorrhage nor extravasation
of contrast media. The hemiplegia and aphasia resolved just after the procedure. The
patient discharged from our hospital without motor weakness on postoperative day 10.
Figure 6: (a) A three-dimensional angiography shows a small aneurysm (white arrowhead) and
recanalized branch. R: Right. (b) Postoperative angiography demonstrates complete
recanalization to the peripheral area
Discussion
Endovascular thrombectomy in patients with acute ischemic stroke is different from
other endovascular operations in terms of lack of preprocedural anatomic information.
In addition, a microcatheter must be navigated into an invisible, small, and fragile
intracranial artery on fluoroscopy. Reportedly, the prevalence of unruptured aneurysms
in adults was 2.3%–6.0%,[[8]] and the risk of permanent neurologic disability and death associated with intraprocedural
aneurysm perforation was 29%–39%, even if treatment of the aneurysms was aimed at
coiling.[[9]] In cases undergoing rt-PA therapy, an intraprocedural unintended aneurysm rupture
must be critical.
We used MPMGW, which had been reported by Sato et al.,[[2]] for all acute thrombectomy procedures. MPMGW is safe because it prevents unexpected
wire migration into perforators. The wire also provides better vessel selectivity
with torque. When a guide catheter cannot be advanced up to the common carotid artery,
the MPMGW allows selection into the internal carotid artery navigation into intracranial
small arteries with the same tip shape. It also provides better microcatheter trackability
because it acts like an anchor in the distal vessels compared to a conventional rectal-angled
shape. Moreover, Ohshima et al.[[3]] reported that it provides information about the quality of the clot during clot
penetration. Devices were selected based on the evaluation of the clot, soft or hard,
by the wire configuration and behavior. In cases with an extremely hard clot, their
corkscrew penetrating method allowed for amazing en bloc clot retrieval.[[4]]
In our case, when the arterial bulge was found, the possibility of an aneurysm was
conceived early. However, because the angiogram showed a remaining nonvascularized
area, we had to seek the occluded arterial branch considering the patient's severe
symptom. When the round tip of the MPMGW was advanced gently into the bulge, the patient
showed unusual body movement. Although some patients often complain of a headache
when the microguidewire is passed in the normal vessels, the patient showed head deviation
with a little stress against the vessel wall of the bulge. Therefore, we considered
the presence of an abnormality and decided to withdraw the procedure. When the origin
of the occluded vessel is undetectable, we usually obtain a three-dimensional angiogram
to expose it. In our case, the occluded artery appeared spontaneously recanalized
just before the three-dimensional angiogram according to the effectiveness of the
intravenous rt-PA.
Recently, Keulers et al.[[10]] reported the wireless microcatheter passing the clot to prevent vessel perforation
by microguidewire. In this report, the success rate of passing the clot was 71.8%,
and there was no hemorrhagic complication. We think the direct pushing of the microcatheter
may cause a devastating subarachnoid hemorrhage in our case due to the bolder movement
than the microwire. We believe our round tip of microwire is safer than the tip of
microcatheter.
This report has some limitations. First, physicians require skills and tips for manual
shaping of the MPMGW. The shaping mandrel attached with Chikai microguidewire series
(Asahi Intecc) provides better handling than others. If the round shape is memorized
to the far tip, it becomes difficult to insert into microcatheters. Therefore, we
recommend that the tip should remain straight for 2 mm. Second, the shapability of
the wire is different for each product. The Tenrou microguidewire (Kaneka, Osaka,
Japan) can be shaped into a modified pigtail as well as the Chikai 14 microguidewire.
Whereas the Traxcess microguidewire (Terumo, Tokyo, Japan) cannot be shaped owing
to its core wire structure in the tip. Third, in our case, we judged the dilatation
to be an aneurysm according to the patient's unusual body movement. Complaints from
patients are various, and it is impossible to establish a criteria. We believe a sign
from patients during operation is very important. Despite these limitations, we believe
our results will contribute significantly toward more secure endovascular thrombectomy
than those currently in use.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form the patient has given his consent for his images and other clinical information
to be reported in the journal. The patient understands that his name and initial will
not be published and due efforts will be made to conceal his identity, but anonymity
cannot be guaranteed.
