- Email: [email protected]
Relationship Between Clot Quality and Microguidewire Configuration During Endovascular Thrombectomy for Acute Ischemic Stroke
Accepted Manuscript Relationship between clot quality and microguidewire configuration during endovascular thrombectomy for acute ischemic stroke Tomotaka Ohshima, Kojiro Ishikawa, Shunsaku Goto, Taiki Yamamoto PII:
S1878-8750(17)31406-7
DOI:
10.1016/j.wneu.2017.08.105
Reference:
WNEU 6355
To appear in:
World Neurosurgery
Received Date: 16 June 2017 Revised Date:
15 August 2017
Accepted Date: 16 August 2017
Please cite this article as: Ohshima T, Ishikawa K, Goto S, Yamamoto T, Relationship between clot quality and microguidewire configuration during endovascular thrombectomy for acute ischemic stroke, World Neurosurgery (2017), doi: 10.1016/j.wneu.2017.08.105. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Ohshima 1
ACCEPTED MANUSCRIPT
Original article
SC
endovascular thrombectomy for acute ischemic stroke
RI PT
Relationship between clot quality and microguidewire configuration during
Department of Neurosurgery, Kariya Toyota General Hospital, Kariya, Japan
TE D
1
M AN U
Tomotaka Ohshima1, Kojiro Ishikawa1, Shunsaku Goto1, and Taiki Yamamoto1
Corresponding author: Tomotaka Ohshima, MD, PhD
EP
5-15 Sumiyoshi-cho, Kariya, Aichi, 448 8505, Japan.
AC C
Tel: +81-566-21-2450; Fax: +81-566-22-2493; Email: [email protected]
1
Ohshima 2
ACCEPTED MANUSCRIPT
Keywords: acute ischemic stroke; clot; endovascular thrombectomy; microguidewire
RI PT
Abbreviations: None
Conflicts of interest: The authors declare no conflict of interest.
SC
Funding: The authors received no financial support for the research, authorship, and/or
AC C
EP
TE D
M AN U
publication of this article.
2
Ohshima 3
ACCEPTED MANUSCRIPT
Abstract Background and Purpose: Although endovascular approaches for acute ischemic
RI PT
stroke have been developed, the appropriate selection and sequence of device application or other treatments is unclear. If information about the clot quality can be
SC
obtained before the selection of devices, fast recanalization with a suitable device and
M AN U
strategy can be achieved. We studied the relationship between clot quality and the configuration of a microguidewire during endovascular thrombectomy. Materials and Methods: This prospective single-center study included all patients who were admitted for acute ischemic stroke between October 2015 and June 2017 and
TE D
underwent emergency endovascular thrombectomy. We used a modified pigtail-shaped microguidewire to penetrate clots. The configurations under the X-ray were
AC C
quality.
EP
distinguished into two types and assessed according to collected clot appearance and
Results: A total of 54 patients underwent acute endovascular thrombectomy. When the tip of the microguidewire became stuck against a clot during penetration, the clot was solid and hard with statistical significance (p = 0.013). Conclusion: Our results showed that we can select a suitable device and strategy for fast recanalization according to information about clot quality obtained using the
3
Ohshima 4
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
modified pigtail-shaped microguidewire.
4
Ohshima 5
ACCEPTED MANUSCRIPT
Introduction Fast recanalization is the most effective treatment for acute ischemic stroke due
RI PT
to major cerebral artery occlusion.1 Endovascular approaches for acute ischemic
stroke continues to evolve. Mechanical thrombectomy using a stent clot retriever
SC
results in the immediate restoration of cerebral blood flow, and compared with previous methods, this approach is associated with faster and higher rates of
M AN U
recanalization.2 However, the optimal selection and sequence of application for endovascular devices or other methods to treat patients with acute stroke are uncertain. We report our experience with a stent clot retriever for the first-line treatment of acute
TE D
ischemic stroke. The device allows the operator to assess the clot quality during the penetration of clots with a modified pigtail-shaped microguidewire and, using that
EP
information, select the most appropriate devices and adjunctive techniques for fast
AC C
and secure recanalization.
Methods Patients
This prospective single-center study included all patients who were admitted to our institution for acute ischemic stroke between October 2015 and June 2017 and
5
Ohshima 6
ACCEPTED MANUSCRIPT
underwent emergency endovascular thrombectomy. A National Institutes of Health Stroke Scale score was determined for each patient.3 Successful recanalization was
RI PT
defined as a thrombolysis in cerebral infarction score of 2b to 3. A good clinical outcome was defined as a modified Rankin Scale score of ≤ 2 at 30 days.
SC
Endovascular procedure
M AN U
All endovascular treatments were performed under local anesthesia. Access was achieved using a percutaneous transfemoral technique. In cases of anterior circulation stroke, 9 French guiding catheters with a balloon (Cello; Medtronic, Minneapolis, MN, USA) were placed in the cervical internal carotid artery, and 5 French aspiration
TE D
catheters (5Max ACE; Penumbra, Alameda, CA, USA) were coaxially advanced proximal to the clot. In cases of posterior circulation stroke, 6 French guiding catheters
EP
were advanced in the vertebral artery. After controlled angiography, a stent delivery
AC C
microcatheter (Marksman; Medtronic) was navigated distal to the thrombus with a Chikai 14 microguidewire (Asahi Intecc, Aichi, Japan) shaped into a modified pigtail using the attached mandrel (Fig. 1). Before the clot penetration, the balloon guide was inflated to prevent the distal migration of clot. We judged the quality of the clot during contact between the clot and the tip of the wire. When the wire penetrated the clot and maintained the pigtail shape, the clot was considered soft, and we designated the
6
Ohshima 7
ACCEPTED MANUSCRIPT
configuration of the wire on the X-ray as type A. On the contrary, when the wire became stuck against the clot, the clot was considered hard, and we designated this
RI PT
configuration as type B. We confirmed these type assignments in vitro using sham clots (Fig. 2).
SC
Choice of strategy based on clot quality
M AN U
When the clot was soft, our priority was speed to recanalization. The aspiration catheter was maintained in a relatively proximal position. A stent retriever was navigated as quickly as possible without any adjunctive techniques. Conversely, for hard clots, our priority was secure recanalization. The aspirator was advanced to a
TE D
position proximal to the clot. Under continuous aspiration, a stent retriever was deployed with a push-and-fluff technique.4 The stent retriever was withdrawn into the
EP
aspiration catheter and removed completely from the entire system. Subsequently, the
AC C
aspiration catheter was removed under continuous aspiration to collect any residual microscopic or large fragments of the clot. Angiograms were examined for residual clots, and the balloon guide was deflated. These procedures were repeated until successful recanalization was achieved. Assessment of retrieved clots The collected clots were divided into two groups according to their appearances.
7
Ohshima 8
ACCEPTED MANUSCRIPT
Group 1 contained solid clots attached to the stent, or in the pump of aspirator. Group 2 included semi-liquid clots attached to the stent, or undetectable clots in the pump.
RI PT
Statistical analyses were performed using EZR software (version 1.31; Saitama Medical Center, Jichi Medical University, Saitama, Japan). Statistical significance was set at
M AN U
SC
p<0.05. Some solid clots were subjected to the pathological examination.
Results
Between October 2015 and June 2017, we performed 54 acute endovascular thrombectomy procedures in our hospital. Their characteristics and clinical results are
TE D
summarized in Table 1. Fifty-three patients (98.1%) were successfully recanalized. Forty-five patients (83.3%) could be recanalized at initial stent withdrawal. Forty-two
EP
patients demonstrated good clinical results at 30 days after the procedure. There was no
AC C
embolization to new territory in this series.
The relationship between the clot appearance and microguidewire configuration is
shown in Table 2. We found statistically significant difference with p = 0.013, when the tip of the microguidewire was stuck to a clot during the penetration (type B), the clot was retrieved as a solid with the stent or in the pump of aspirator (group 1). Representative cases of type A and type B clots are shown in Figures 3 and 4,
8
Ohshima 9
ACCEPTED MANUSCRIPT
respectively. The former example is type A, group 2, and the pathological examination indicated a fresh red thrombus. In the latter figure, the clot was classified as type B,
RI PT
group 1, and the pathological examination revealed a chronic white thrombus with
SC
infiltrated neutrophils and fibrin.
M AN U
Discussion
The best technique for a first attempt at mechanical thrombectomy for acute ischemic stroke remains matter of debate. Several novel approaches have been reported, such as the direct aspiration first pass technique,5 proximal balloon flow arrest, and the
TE D
stent and aspiration combined technique.6-7 It is clear that for the fast reperfusion, simpler methods are superior to complicated approaches; however, the cases in which
EP
occluded arteries resist recanalization require multiple devices and some adjunctive
AC C
techniques. A previous treatment protocol for acute ischemic stroke was developed based on the assessment of clot quality during clot removal with a stent retriever.8 In the present study, we assessed clot quality during penetration with a microguidewire before the selection of devices.
Previously, we reported that the modified pigtail-shaped microguidewire was an extremely safe and versatile method for neurointerventions.9-10 The round tip of the wire 9
Ohshima 10
ACCEPTED MANUSCRIPT
prevents unintended entry into the perforating branches or blebs of an aneurysm or reduces the risks of perforation if it enters them erroneously. The microguidewire is also
RI PT
useful for acute thrombectomy. When a stent retriever is used, the microguidewire must pass through the occluded vessel, which is not delineated by angiography. A
SC
microguidewire with a modified pigtail shape can be safely advanced across a lesion
M AN U
even if there might be an unseen aneurysm in the distal vessel.
When the clot was classified as type A, our priority was speed to recanalization. In our experience, soft clots can be retrieved with any device. Small-caliber stents were used to avoid unexpected vessel injury. Conversely, when the clot was categorized as
TE D
type B, our priority was secure recanalization. The large-caliber aspirator was advanced proximal to the clot, and under the aspiration, a large-caliber stent retriever was
EP
deployed with a push-and-fluff technique.4 After the stent retriever was withdrawn into
AC C
the aspiration catheter, subsequent direct aspiration was performed. The dual clot retrieval was very useful in patients with hard clots. When a hard clot longer than approximately 1.5 cm was encounterd, a corkscrew penetrating method was effective as another adjunctive technique.11
The limitations of this study are the small sample size and single-center clinical setting. Compared with that in previous studies, the time between puncture and 10
Ohshima 11
ACCEPTED MANUSCRIPT
recanalization in our study was much faster. The recanalization rate and clinical outcomes were good and comparable to those in large-scale studies; however, we
RI PT
lacked sufficient statistical power to determine whether our protocol truly influenced outcome. Despite these limitations, we contend that the results of this study make a
SC
significant contribution to the clinical information available for decision-making in
confirmation of these results.
TE D
Conclusions
M AN U
acute stroke intervention. Large-scale, multicenter trials are necessary for further
The results of this study suggest that we can select suitable devices and adjunctive
EP
techniques for fast recanalization according to information about clot quality determined using a modified pigtail-shaped microguidewire. Although this study had a small size
AC C
and took place in a single-center clinical setting, we believe our protocol will contribute to fast and secure recanalization in cases of acute ischemic stroke.
References 1.
Rha JH, Saver JL. The impact of recanalization on ischemic stroke outcome: a
11
Ohshima 12
ACCEPTED MANUSCRIPT
meta-analysis. Stroke, 2007; 38: 967–973. 2.
Serrone JC, Jimenez L, Ringer AJ. The role of endovascular therapy in the
3.
RI PT
treatment of acute ischemic stroke. Neurosurgery, 2014; 74: 133－141.
Bruno A, Saha C, Williams LS: Using change in the national institutes of health stroke scale to measure treatment effect in acute stroke trials. Stroke, 2006; 37:
Haussen DC, Rebello LC, Nougueira RG. Optimizating clot retrieval in acute
M AN U
4.
SC
920–921.
stroke: the push and fluff technique for closed-cell stentrievers. Stroke. 2015; 46: 2838–2842.
Turk AS, Frei D, Fiorella D, Mocco J, Baxter B, Siddiqui A, et al. Adapt fast study:
TE D
5.
a direct aspiration first pass technique for acute stroke thrombectomy. J NeuroIntervent Surg 2014; 6: 260–264.
Humphries W, Hoit D, Doss VT, Elijovich L, Frei D, Loy D, et al. Distal aspiration
EP
6.
AC C
with retrievable stent assisted thrombectomy for the treatment of acute ischemic stroke. J NeuroIntervent Surg 2015; 7: 90–94.
7.
Stampfl S, Pfaff J, Herweh C, Pham M, Schieber S, Ringleb PA, et al. Combined proximal balloon occlusion and distal aspiration: a new approach to prevent distal embolization during neurothrombectomy. J NeuroIntervent Surg 2017; 9: 346–351.
12
Ohshima 13
ACCEPTED MANUSCRIPT
8.
Ishikawa K, Ohshima T, Nishihori M, Imai T, Goto S, Yamamoto T, et al. Treatment protocol based on assessment of clot quality during endovascular
RI PT
thrombectomy for acute ischemic stroke using the Trevo stent retriever. Nagoya J Med Sci 2016; 78: 255–265.
Ohshima T, Nagakura M, Nishizawa T, Kato K. Alpha horizontal stent delivery for
SC
9.
M AN U
coil embolization of a broad-necked large basilar apex aneurysm: a case report. Nagoya J Med Sci 2015; 77: 659–665.
10. Sato M, Ohshima T, Ishikawa K, Goto S, Yamamoto T, Izumi T, et al. A novel technique of safe and versatile microguidewire shaping with neuroendovascular
TE D
therapy: modified pigtail method. J Neuroendovasc Ther 2017; 11: 266–271. 11. Ohshima T, Imai T, Sato M, Goto S, Yamamoto T, Nishizawa T, et al. A novel
EP
technique for higher success rates of recanalization with stent clot retriever:
AC C
corkscrew penetrating method. J Neuroendovasc Ther 2017; 11: 94–98.
Figure legends
Fig. 1. Modified pigtail-shaped microguidewire. Fig. 2. Experiments using simulated clots. A: In a soft clot, the wire keeps its shape after penetration. B: In a hard clot, the wire becomes stuck and bends.
13
Ohshima 14
ACCEPTED MANUSCRIPT
Fig. 3. A, B: Intraprocedural images showing. The red circles indicate the positioning of the clot. The wire was penetrated the clot without any resistance (type A). C: Retrieved
a fresh red thrombus with many red blood cells.
RI PT
stent. A semi-liquid clot (group 2) is attached to the stent. D: Pathological image shows
SC
Fig. 4. A, B: Intraprocedural images showing. The red circles indicate the positioning of
M AN U
the clot. The wire was stuck and bent (type B). C: The retrieved clot was solid (group 1).
AC C
EP
TE D
D: Pathological image shows a white thrombus with infiltrated neutrophils and fibrin.
14
ACCEPTED MANUSCRIPT
Table 1. Caracteristics and results of 54 cases with endovascular thrombectomy mean 71.4 (range, 42 90)
Sex (male : female)
30 : 24
Atrial fibrillation on admission
40 (74%)
pre NIHSS
mean 8 (range, 3
12
ICA terminal
7
M AN U
ICA origin
26)
SC
Location
RI PT
Age (years)
M1 proximal
15
M1 distal
11
M2
6
Others (posterior circulation)
3
TE D
Onset to puncture (min) Devices
EP
Stent retriever alone
101 (range, 40 240)
2 7
Stent retriever with Aspirator
45
AC C
Aspirator alone
Results
TICI 3
31
TICI 2B
22
TICI 2A
1
Puncture to recanalization (min)
mean 21 (range, 11 50)
1
ACCEPTED MANUSCRIPT
45
2
6
3
3
Modified Rankin Scale at 30 days 0
17 2
25
3
5
12
M AN U
1
SC
1
RI PT
Number of pass
6
0
Abbreviations NIHSS: National Institutes of Health Stroke Scale, ICA: internal carotid artery, M: middle cerebral artery,
AC C
EP
TE D
TICI: thrombolysis in cerebral infarction scale
2
ACCEPTED MANUSCRIPT
Table 2. Relationship between clot appearance and configuration of a wire Group 1
Group 2
Total number
Type A
9
17
26
Type B
20
8
Total number
29
25
RI PT
Clot group
28
54
AC C
EP
TE D
M AN U
SC
Wire type
1
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
Highlights ・We aimed to assess the relationship between clot quality and microguidewire configuration in
RI PT
47 patients with acute ischemic stroke who underwent endovascular thrombectomy.
・We found that in soft clots, a modified pigtail-shaped microguidewire maintained its pigtail
M AN U
became stuck to the clot, a solid clot was usually retrieved.
SC
configuration during clot penetration. On the contrary, when the tip of the microguidewire
・Suitable devices and adjunctive techniques for recanalization in acute ischemic stroke can be
AC C
EP
TE D
selected based on clot characteristics determined with the pigtail-shaped microguidewire.
S1878-8750(17)31406-7
DOI:
10.1016/j.wneu.2017.08.105
Reference:
WNEU 6355
To appear in:
World Neurosurgery
Received Date: 16 June 2017 Revised Date:
15 August 2017
Accepted Date: 16 August 2017
Please cite this article as: Ohshima T, Ishikawa K, Goto S, Yamamoto T, Relationship between clot quality and microguidewire configuration during endovascular thrombectomy for acute ischemic stroke, World Neurosurgery (2017), doi: 10.1016/j.wneu.2017.08.105. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Ohshima 1
ACCEPTED MANUSCRIPT
Original article
SC
endovascular thrombectomy for acute ischemic stroke
RI PT
Relationship between clot quality and microguidewire configuration during
Department of Neurosurgery, Kariya Toyota General Hospital, Kariya, Japan
TE D
1
M AN U
Tomotaka Ohshima1, Kojiro Ishikawa1, Shunsaku Goto1, and Taiki Yamamoto1
Corresponding author: Tomotaka Ohshima, MD, PhD
EP
5-15 Sumiyoshi-cho, Kariya, Aichi, 448 8505, Japan.
AC C
Tel: +81-566-21-2450; Fax: +81-566-22-2493; Email: [email protected]
1
Ohshima 2
ACCEPTED MANUSCRIPT
Keywords: acute ischemic stroke; clot; endovascular thrombectomy; microguidewire
RI PT
Abbreviations: None
Conflicts of interest: The authors declare no conflict of interest.
SC
Funding: The authors received no financial support for the research, authorship, and/or
AC C
EP
TE D
M AN U
publication of this article.
2
Ohshima 3
ACCEPTED MANUSCRIPT
Abstract Background and Purpose: Although endovascular approaches for acute ischemic
RI PT
stroke have been developed, the appropriate selection and sequence of device application or other treatments is unclear. If information about the clot quality can be
SC
obtained before the selection of devices, fast recanalization with a suitable device and
M AN U
strategy can be achieved. We studied the relationship between clot quality and the configuration of a microguidewire during endovascular thrombectomy. Materials and Methods: This prospective single-center study included all patients who were admitted for acute ischemic stroke between October 2015 and June 2017 and
TE D
underwent emergency endovascular thrombectomy. We used a modified pigtail-shaped microguidewire to penetrate clots. The configurations under the X-ray were
AC C
quality.
EP
distinguished into two types and assessed according to collected clot appearance and
Results: A total of 54 patients underwent acute endovascular thrombectomy. When the tip of the microguidewire became stuck against a clot during penetration, the clot was solid and hard with statistical significance (p = 0.013). Conclusion: Our results showed that we can select a suitable device and strategy for fast recanalization according to information about clot quality obtained using the
3
Ohshima 4
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
modified pigtail-shaped microguidewire.
4
Ohshima 5
ACCEPTED MANUSCRIPT
Introduction Fast recanalization is the most effective treatment for acute ischemic stroke due
RI PT
to major cerebral artery occlusion.1 Endovascular approaches for acute ischemic
stroke continues to evolve. Mechanical thrombectomy using a stent clot retriever
SC
results in the immediate restoration of cerebral blood flow, and compared with previous methods, this approach is associated with faster and higher rates of
M AN U
recanalization.2 However, the optimal selection and sequence of application for endovascular devices or other methods to treat patients with acute stroke are uncertain. We report our experience with a stent clot retriever for the first-line treatment of acute
TE D
ischemic stroke. The device allows the operator to assess the clot quality during the penetration of clots with a modified pigtail-shaped microguidewire and, using that
EP
information, select the most appropriate devices and adjunctive techniques for fast
AC C
and secure recanalization.
Methods Patients
This prospective single-center study included all patients who were admitted to our institution for acute ischemic stroke between October 2015 and June 2017 and
5
Ohshima 6
ACCEPTED MANUSCRIPT
underwent emergency endovascular thrombectomy. A National Institutes of Health Stroke Scale score was determined for each patient.3 Successful recanalization was
RI PT
defined as a thrombolysis in cerebral infarction score of 2b to 3. A good clinical outcome was defined as a modified Rankin Scale score of ≤ 2 at 30 days.
SC
Endovascular procedure
M AN U
All endovascular treatments were performed under local anesthesia. Access was achieved using a percutaneous transfemoral technique. In cases of anterior circulation stroke, 9 French guiding catheters with a balloon (Cello; Medtronic, Minneapolis, MN, USA) were placed in the cervical internal carotid artery, and 5 French aspiration
TE D
catheters (5Max ACE; Penumbra, Alameda, CA, USA) were coaxially advanced proximal to the clot. In cases of posterior circulation stroke, 6 French guiding catheters
EP
were advanced in the vertebral artery. After controlled angiography, a stent delivery
AC C
microcatheter (Marksman; Medtronic) was navigated distal to the thrombus with a Chikai 14 microguidewire (Asahi Intecc, Aichi, Japan) shaped into a modified pigtail using the attached mandrel (Fig. 1). Before the clot penetration, the balloon guide was inflated to prevent the distal migration of clot. We judged the quality of the clot during contact between the clot and the tip of the wire. When the wire penetrated the clot and maintained the pigtail shape, the clot was considered soft, and we designated the
6
Ohshima 7
ACCEPTED MANUSCRIPT
configuration of the wire on the X-ray as type A. On the contrary, when the wire became stuck against the clot, the clot was considered hard, and we designated this
RI PT
configuration as type B. We confirmed these type assignments in vitro using sham clots (Fig. 2).
SC
Choice of strategy based on clot quality
M AN U
When the clot was soft, our priority was speed to recanalization. The aspiration catheter was maintained in a relatively proximal position. A stent retriever was navigated as quickly as possible without any adjunctive techniques. Conversely, for hard clots, our priority was secure recanalization. The aspirator was advanced to a
TE D
position proximal to the clot. Under continuous aspiration, a stent retriever was deployed with a push-and-fluff technique.4 The stent retriever was withdrawn into the
EP
aspiration catheter and removed completely from the entire system. Subsequently, the
AC C
aspiration catheter was removed under continuous aspiration to collect any residual microscopic or large fragments of the clot. Angiograms were examined for residual clots, and the balloon guide was deflated. These procedures were repeated until successful recanalization was achieved. Assessment of retrieved clots The collected clots were divided into two groups according to their appearances.
7
Ohshima 8
ACCEPTED MANUSCRIPT
Group 1 contained solid clots attached to the stent, or in the pump of aspirator. Group 2 included semi-liquid clots attached to the stent, or undetectable clots in the pump.
RI PT
Statistical analyses were performed using EZR software (version 1.31; Saitama Medical Center, Jichi Medical University, Saitama, Japan). Statistical significance was set at
M AN U
SC
p<0.05. Some solid clots were subjected to the pathological examination.
Results
Between October 2015 and June 2017, we performed 54 acute endovascular thrombectomy procedures in our hospital. Their characteristics and clinical results are
TE D
summarized in Table 1. Fifty-three patients (98.1%) were successfully recanalized. Forty-five patients (83.3%) could be recanalized at initial stent withdrawal. Forty-two
EP
patients demonstrated good clinical results at 30 days after the procedure. There was no
AC C
embolization to new territory in this series.
The relationship between the clot appearance and microguidewire configuration is
shown in Table 2. We found statistically significant difference with p = 0.013, when the tip of the microguidewire was stuck to a clot during the penetration (type B), the clot was retrieved as a solid with the stent or in the pump of aspirator (group 1). Representative cases of type A and type B clots are shown in Figures 3 and 4,
8
Ohshima 9
ACCEPTED MANUSCRIPT
respectively. The former example is type A, group 2, and the pathological examination indicated a fresh red thrombus. In the latter figure, the clot was classified as type B,
RI PT
group 1, and the pathological examination revealed a chronic white thrombus with
SC
infiltrated neutrophils and fibrin.
M AN U
Discussion
The best technique for a first attempt at mechanical thrombectomy for acute ischemic stroke remains matter of debate. Several novel approaches have been reported, such as the direct aspiration first pass technique,5 proximal balloon flow arrest, and the
TE D
stent and aspiration combined technique.6-7 It is clear that for the fast reperfusion, simpler methods are superior to complicated approaches; however, the cases in which
EP
occluded arteries resist recanalization require multiple devices and some adjunctive
AC C
techniques. A previous treatment protocol for acute ischemic stroke was developed based on the assessment of clot quality during clot removal with a stent retriever.8 In the present study, we assessed clot quality during penetration with a microguidewire before the selection of devices.
Previously, we reported that the modified pigtail-shaped microguidewire was an extremely safe and versatile method for neurointerventions.9-10 The round tip of the wire 9
Ohshima 10
ACCEPTED MANUSCRIPT
prevents unintended entry into the perforating branches or blebs of an aneurysm or reduces the risks of perforation if it enters them erroneously. The microguidewire is also
RI PT
useful for acute thrombectomy. When a stent retriever is used, the microguidewire must pass through the occluded vessel, which is not delineated by angiography. A
SC
microguidewire with a modified pigtail shape can be safely advanced across a lesion
M AN U
even if there might be an unseen aneurysm in the distal vessel.
When the clot was classified as type A, our priority was speed to recanalization. In our experience, soft clots can be retrieved with any device. Small-caliber stents were used to avoid unexpected vessel injury. Conversely, when the clot was categorized as
TE D
type B, our priority was secure recanalization. The large-caliber aspirator was advanced proximal to the clot, and under the aspiration, a large-caliber stent retriever was
EP
deployed with a push-and-fluff technique.4 After the stent retriever was withdrawn into
AC C
the aspiration catheter, subsequent direct aspiration was performed. The dual clot retrieval was very useful in patients with hard clots. When a hard clot longer than approximately 1.5 cm was encounterd, a corkscrew penetrating method was effective as another adjunctive technique.11
The limitations of this study are the small sample size and single-center clinical setting. Compared with that in previous studies, the time between puncture and 10
Ohshima 11
ACCEPTED MANUSCRIPT
recanalization in our study was much faster. The recanalization rate and clinical outcomes were good and comparable to those in large-scale studies; however, we
RI PT
lacked sufficient statistical power to determine whether our protocol truly influenced outcome. Despite these limitations, we contend that the results of this study make a
SC
significant contribution to the clinical information available for decision-making in
confirmation of these results.
TE D
Conclusions
M AN U
acute stroke intervention. Large-scale, multicenter trials are necessary for further
The results of this study suggest that we can select suitable devices and adjunctive
EP
techniques for fast recanalization according to information about clot quality determined using a modified pigtail-shaped microguidewire. Although this study had a small size
AC C
and took place in a single-center clinical setting, we believe our protocol will contribute to fast and secure recanalization in cases of acute ischemic stroke.
References 1.
Rha JH, Saver JL. The impact of recanalization on ischemic stroke outcome: a
11
Ohshima 12
ACCEPTED MANUSCRIPT
meta-analysis. Stroke, 2007; 38: 967–973. 2.
Serrone JC, Jimenez L, Ringer AJ. The role of endovascular therapy in the
3.
RI PT
treatment of acute ischemic stroke. Neurosurgery, 2014; 74: 133－141.
Bruno A, Saha C, Williams LS: Using change in the national institutes of health stroke scale to measure treatment effect in acute stroke trials. Stroke, 2006; 37:
Haussen DC, Rebello LC, Nougueira RG. Optimizating clot retrieval in acute
M AN U
4.
SC
920–921.
stroke: the push and fluff technique for closed-cell stentrievers. Stroke. 2015; 46: 2838–2842.
Turk AS, Frei D, Fiorella D, Mocco J, Baxter B, Siddiqui A, et al. Adapt fast study:
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5.
a direct aspiration first pass technique for acute stroke thrombectomy. J NeuroIntervent Surg 2014; 6: 260–264.
Humphries W, Hoit D, Doss VT, Elijovich L, Frei D, Loy D, et al. Distal aspiration
EP
6.
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with retrievable stent assisted thrombectomy for the treatment of acute ischemic stroke. J NeuroIntervent Surg 2015; 7: 90–94.
7.
Stampfl S, Pfaff J, Herweh C, Pham M, Schieber S, Ringleb PA, et al. Combined proximal balloon occlusion and distal aspiration: a new approach to prevent distal embolization during neurothrombectomy. J NeuroIntervent Surg 2017; 9: 346–351.
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8.
Ishikawa K, Ohshima T, Nishihori M, Imai T, Goto S, Yamamoto T, et al. Treatment protocol based on assessment of clot quality during endovascular
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thrombectomy for acute ischemic stroke using the Trevo stent retriever. Nagoya J Med Sci 2016; 78: 255–265.
Ohshima T, Nagakura M, Nishizawa T, Kato K. Alpha horizontal stent delivery for
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9.
M AN U
coil embolization of a broad-necked large basilar apex aneurysm: a case report. Nagoya J Med Sci 2015; 77: 659–665.
10. Sato M, Ohshima T, Ishikawa K, Goto S, Yamamoto T, Izumi T, et al. A novel technique of safe and versatile microguidewire shaping with neuroendovascular
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therapy: modified pigtail method. J Neuroendovasc Ther 2017; 11: 266–271. 11. Ohshima T, Imai T, Sato M, Goto S, Yamamoto T, Nishizawa T, et al. A novel
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technique for higher success rates of recanalization with stent clot retriever:
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corkscrew penetrating method. J Neuroendovasc Ther 2017; 11: 94–98.
Figure legends
Fig. 1. Modified pigtail-shaped microguidewire. Fig. 2. Experiments using simulated clots. A: In a soft clot, the wire keeps its shape after penetration. B: In a hard clot, the wire becomes stuck and bends.
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Fig. 3. A, B: Intraprocedural images showing. The red circles indicate the positioning of the clot. The wire was penetrated the clot without any resistance (type A). C: Retrieved
a fresh red thrombus with many red blood cells.
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stent. A semi-liquid clot (group 2) is attached to the stent. D: Pathological image shows
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Fig. 4. A, B: Intraprocedural images showing. The red circles indicate the positioning of
M AN U
the clot. The wire was stuck and bent (type B). C: The retrieved clot was solid (group 1).
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D: Pathological image shows a white thrombus with infiltrated neutrophils and fibrin.
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Table 1. Caracteristics and results of 54 cases with endovascular thrombectomy mean 71.4 (range, 42 90)
Sex (male : female)
30 : 24
Atrial fibrillation on admission
40 (74%)
pre NIHSS
mean 8 (range, 3
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ICA terminal
7
M AN U
ICA origin
26)
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Location
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Age (years)
M1 proximal
15
M1 distal
11
M2
6
Others (posterior circulation)
3
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Onset to puncture (min) Devices
EP
Stent retriever alone
101 (range, 40 240)
2 7
Stent retriever with Aspirator
45
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Aspirator alone
Results
TICI 3
31
TICI 2B
22
TICI 2A
1
Puncture to recanalization (min)
mean 21 (range, 11 50)
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45
2
6
3
3
Modified Rankin Scale at 30 days 0
17 2
25
3
5
12
M AN U
1
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1
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Number of pass
6
0
Abbreviations NIHSS: National Institutes of Health Stroke Scale, ICA: internal carotid artery, M: middle cerebral artery,
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TICI: thrombolysis in cerebral infarction scale
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Table 2. Relationship between clot appearance and configuration of a wire Group 1
Group 2
Total number
Type A
9
17
26
Type B
20
8
Total number
29
25
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Clot group
28
54
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M AN U
SC
Wire type
1
AC C
EP
TE D
M AN U
SC
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AC C
EP
TE D
M AN U
SC
RI PT
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AC C
EP
TE D
M AN U
SC
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AC C
EP
TE D
M AN U
SC
RI PT
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Highlights ・We aimed to assess the relationship between clot quality and microguidewire configuration in
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47 patients with acute ischemic stroke who underwent endovascular thrombectomy.
・We found that in soft clots, a modified pigtail-shaped microguidewire maintained its pigtail
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became stuck to the clot, a solid clot was usually retrieved.
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configuration during clot penetration. On the contrary, when the tip of the microguidewire
・Suitable devices and adjunctive techniques for recanalization in acute ischemic stroke can be
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selected based on clot characteristics determined with the pigtail-shaped microguidewire.