Journal of Neuroendovascular Therapy

Advance Published Date: March 22, 2021

DOI: 10.5797/jnet.oa.2020-0128

Initial Result of Stroke Care at the Stroke
Center in a New Hospital Opened by the
Merger of Three Facilities with Different
Management Bases: Effect of Stroke
Center on Mechanical Thrombectomy
Hiroshi Sakaida,1 Fuki Goto,1 Atsushi Yamamoto,1 Kazuhide Hamada,1 Katsura Kuroki,1 Tomoyuki Furuta,2Kiyomi Odachi,2 Ryogen Sasaki,2 Kazuhiro Furukawa,3 Yuki Nakajima,4 and Shigeo Arikawa5

Objective: The most important function required for the stroke center is prompt treatment for acute stroke. We report theinitial results of stroke care under the new medical care system of stroke center in a new hospital that merges threehospitals with different management bases to verify the effect of stroke center on mechanical thrombectomy.
Methods: We investigated changes in the number of inpatients and surgical treatments compared with the past 3 years(Stages I, II, and III) with stage IV one year after the new hospital was opened, and examined the effect of establishinga stroke center on mechanical thrombectomy for acute main cerebral artery occlusion.
Results: From stage I to stage IV, the number of hospitalized patients increased from 396, 485, 482 to 630, respectively,
and the proportion of patients with cerebrovascular disease increased from 57.6%, 55.7%, 60.4% to 68.3%, respectively.
Total surgical treatment increased from 137, 195, 224 to 297, respectively, especially endovascular therapy increased
markedly from 22, 36, 68 to 118, respectively. The main treatment contents of endovascular treatment in stage IV were
ruptured cerebral aneurysm embolization 22 cases, unruptured cerebral aneurysm embolization 13 cases, carotid arterystenting 23 cases, other intracranial or extracranial artery angioplasty/stenting 9 cases, and mechanical thrombectomy
34 cases. In particular, mechanical thrombectomy was significantly increased to 34 in stage IV, compared to 4 in stage
I, 4 in stage II, and 17 in stage III (degree of contribution [DC] 25.0%, contribution ratio [CR] 34.0%).
Conclusion: With the establishment of the stroke center, the number of cases of acute cerebral infarction within theadaptation time who received mechanical thrombectomy remarkably increased. It is considered that the effect andvalidity of function aggregation by establishing stroke center are shown.
Keywords▶ stroke center, endovascular therapy, mechanical thrombectomy

Introduction
In the United States, recombinant tissue-type plasminogenactivator (rt-PA) intravenous therapy was approved in 1996,
the requirements for a primary stroke center were established in 2000 with the aim of spread of thrombolytic
Department of Neurosurgery, Stroke Center, Kuwana City Medical
Center, Kuwana, Mie, Japan
2Department of Neurology, Stroke Center, Kuwana City Medical
Center, Kuwana, Mie, Japan
3Department of Neurosurgery, Hisai Neurosurgery Clinic, Tsu,
Mie, Japan
4Department of Neurology, Suzuka Kaisei Hospital, Suzuka, Mie,Japan
5Department of Neurology, Ise Municipal General Hospital, Ise,
Mie, Japan1therapy, and facility certification was started in 2003.1) Furthermore, the requirements for a comprehensive stroke center were announced in 2005, and institutional approval wasstarted in 2012.2) In Japan, the J-ASPECT Study Group’s
survey of stroke medical facilities that began in 2010
revealed regional disparities in medical care systems.3) The
Received: June 20, 2020; Accepted: February 9, 2021
Corresponding author: Hiroshi Sakaida. Department of Neurosurgery, Kuwana City Medical Center, 3-11, Kotobukicho, Kuwana,Mie 511-0061, Japan
Email: sakaidah@kuwanacmc.or.jp
This work is licensed under a Creative
Commons Attribution-NonCommercialNoDerivatives International License.
©2021 The Japanese Society for Neuroendovascular Therapy

1Journal of Neuroendovascular Therapy

Advance Published Date: March 22, 2021

SaSaSSa SS et aS.

Japan Stroke Society and the Japanese Circulation Society
announced the 5-year Plan for Overcoming Stroke and Cardiovascular Diseases in December 2016, and as a problem
related to the medical system, there is no certification system for primary stroke centers and comprehensive stroke
centers. It was pointed out that there is an urgent need toestablish a stroke medical care system and certification system because no cooperation had been established with primary emergency hospitals.4) The relevant academic societies
and the administration proceeded with the preparations, andthe certification of the primary stroke center of the Japan
Stroke Society began in September 2019. Around this time,
the Basic Act on Countermeasures for Stroke and Cardiovascular disease was enacted in December 2018, andenforced in December 2019.5) Then came the era of legally
promoting the prevention of stroke and cardiovascular disease and the establishment of an efficient and appropriate
treatment system.
Kuwana City is located in the northernmost part of Mie
Prefecture, on the prefectural border between Aichi and
Gifu Prefectures. Kuwana City has a relatively large population as a commuting area of Nagoya City and a high proportion of the working-age population compared to otherareas in Mie Prefecture. However, the full-time facility forneurosurgery was only the former Kuwana Municipal Hospital, which had an old and insufficient facility operated witha small number of staff. It was also an environment in which
other circulatory diseases such as cardiology and cardiovascular surgery had to depend on other facilities. As a result,it was difficult to provide sufficient stroke medical care, andthere was a problem that emergency patients leaked out of
the medical service area. Other medical fields had similar
problems, and it was an urgent issue to construct a functional medical system by consolidating from a small-scale
distributed medical system. To solve this problem, the former Kuwana Municipal Hospital, a public hospital, became
the Kuwana West Medical Center, the former Yamamoto
General Hospital, a private hospital, became the Kuwana
East Medical Center, and the former Hirata Cardiovascular
Hospital, a private hospital, became the Kuwana South
Medical Center, and these three centers were systematicallyintegrated to establish the Kuwana City Medical Center in2012. The construction of a new hospital started in 2015,
and a new facility of the Kuwana City Medical Center
opened in May 2018, realizing an integrated merger byreorganizing hospitals of public and private sectors withdifferent management bases, although such a merged facility was extremely rare in Japan. The number of beds

2

decreased from 662 beds in the three hospitals to 400 beds,
and the number of staff decreased from 984 to 908, and
68% of all staff had no experience of specialized strokecare. Expectations for new hospital from citizens, emergency services, and nearby medical facilities were high, anda rapid increase in stroke patients was expected.
The most important function required for the stroke
center is mechanical thrombectomy among various stroke
medical care, because acute cerebral artery occlusion has alarge number of cases, and to improve the survival rate andthe ratio of favorable prognosis, it is necessary to increase
the number of patients who can be delivered in time bysystematic improvement. In establishing a stroke center,
any facility requires a great deal of effort to improve thein-hospital system and the emergency transportation system.
In this paper, we report the initial results on changes inpatient numbers, changes in surgical treatment, and increased
endovascular treatment for patients with acute stroke by
establishing a stroke center in a new hospital opened througha rare process.

Materials and Methods
The period from May 2018 to April 2019, 1 year after the
new hospital was opened, was set as stage IV. The transitions of number of inpatients, total number of surgical therapies, and endovascular treatments performed at our stroke
center were compared with May 2015–April 2016 as stageI, May 2016–April 2017 as stage II, and May 2017–April
2018 as stage III. Among endovascular treatments, we
compared changes in stages I–IV for ruptured cerebral
aneurysm, unruptured cerebral aneurysm, internal carotid
artery stenosis, other intracranial/extracranial occlusive
lesions, and acute main cerebral artery occlusions. By calculating the degree of contribution (DC) and the contribution ratio (CR), the effect of establishing a stroke center
was verified.

Results
Changes in the number of inpatients (Table 1 andFig. 1)
From stage I to stage IV, the number of hospitalized
patients increased from 396, 485, 482 to 630, respectively.
In particular, the increase in ischemic cerebrovascular disease was remarkable among various acute strokes, and the
proportion of patients with cerebrovascular disease increased
from 57.6%, 55.7%, 60.4% to 68.3%, respectively.

Journal of Neuroendovascular Therapy

Advance Published Date: March 22, 2021
InStSaS IeIISt oI StIoSe IaIe at tIe StIoSe IenteI Sn a IeI SoIIStaS

Table 1 Number of inpatients from stage I to stage IV

Stage In
Total
Cerebrovascular disease
Subarachnoid hemorrhage
Intracerebral hemorrhage
Ischemic cerebrovascular disease
Unruptured aneurysm
AVM/AVF
Brain tumor
Spine/spinal cord disease
Head injury
Others

396
228
22
67
126
8
5
7
15
106
40

Stage II
%

n

57.6
5.6
16.9
31.8
2.0
1.3
1.8
3.8
26.8
10.1

485
270
20
64
160
17
9
6
59
107
43

Stage III
%

n

55.7
4.1
13.2
33.0
3.5
1.9
1.3
12.2
22.1
8.9

482
291
33
58
168
16
16
12
34
103
42

Stage IV
%

n

%

60.4
6.8
12.0
34.9
3.3
3.3
2.5
7.1
21.4
8.7

630
430
38
79
249
47
17
29
50
97
24

68.3
6.0
12.5
39.5
7.5
2.7
4.6
7.9
15.4
3.8

The number of hospitalized patients increased from 396, 485, 482 to 630 from stage I to stage IV. In particular, ischemic stroke increased compared to othercerebrovascular diseases in stage IV. AVF: arteriovenous fistula; AVM: arteriovenous malformation

630
SAH
ICH

485

482

Number of cases

396

68.3%
55.7%

Ischemic CVD

60.4%

57.6%
Un-ruptured An
AVM / AVF
Brain tumor
Spine / spinal cord
Head injury
Others

I

II

III

IV

Fig. 1 Changes in the number of hospitalized patients and the proportion of cerebrovascular diseases fromstage I to stage IV. The number of hospitalized patients with cerebrovascular diseases increased markedly instage IV. The proportion of inpatients with cerebrovascular diseases from stage I to stage IV increased 57.6%,
55.7%, 60.4% to 68.3%, respectively. An: aneurysm; AVF: arteriovenous fistula; AVM: arteriovenous malformation; CVD: cerebrovascular disease; ICH: intracerebral hemorrhage; SAH: subarachnoid hemorrhage;

Changes in the total number of surgical therapy(Table 2 and Fig. 2)
From stage I to stage IV, total number of surgicaltherapy increased from 137, 195, 224 to 297, respectively. With the exception of head injury and others, direct
surgery for cerebrovascular disease, brain tumor, and spinal disease was on the rise. Endovascular therapy increased
markedly from 22, 36, 68 to 118, respectively.
Changes in the number of endovascular therapy(Table 3 and Fig. 3)
The total number of endovascular treatments before opening a new hospital was gradually increasing, with 22 in stage I,

36 in stage II, 68 in stage III, and the number of treatments instage IV after the hospital was opened remarkably increased to118. Table 3 and Fig. 3 show the number of endovasculartreatments for the representative cerebrovascular diseases. The
number of ruptured cerebral aneurysm, unruptured cerebral
aneurysm, internal carotid artery stenosis, and other intracranial/extracranial occlusive lesions tended to increase on average, and the increase in acute main cerebral artery occlusions
was particularly remarkable. Table 3 shows the increasing
ratio from the previous stage, DC, and CR for each stage. The
increasing ratio was high in stage II internal carotid artery stenosis (220.0%), stage III ruptured cerebral aneurysm(183.3%), other intracranial/extracranial occlusive lesions

3

Journal of Neuroendovascular Therapy

Advance Published Date: March 22, 2021

SaSaSSa SS et aS.

Table 2 Number of all surgical therapy from stage I to stage IV

Stage In
Total
Surgery
Cerebrovascular disease
Aneurysm clipping
ICH removal
AVM removal
Carotid endarterectomy/bypass
Brain tumor removal
Spine/spinal cord surgery
Head injury surgery
OthersEndovascular therapy

Stage II
%

137
12
6
5
0
1
2
6
44
51
22

n

Stage III
%

195
8.8
4.4
3.6
0.0
0.7
1.5
4.4
32.1
37.2
16.0

11
2
6
1
2
0
32
60
56
36

n

Stage IV
%

224
5.6
1.0
3.1
0.5
1.0
0.0
16.4
30.8
28.7
18.5

18
5
11
2
0
2
31
50
55
68

n

%

297
8.0
2.2
5
0.9
0.0
0.9
13.8
22.3
24.6
30.4

32
6
15
6
7
14
35
51
45
118

11.5
2.0
5.1
2.0
2.4
4.7
11.8
17.2
15.1
39.7

Total number of surgical therapy increased from 137, 195, 224 to 297, respectively. In particular, endovascular therapy increased markedly from 22, 36, 68 to
118 in stage IV. AVM: arteriovenous malformation; ICH: intracerebral hemorrhage

297
ICH removal
CEA/Bypass

An clipping
AVM removal
Brain tumor removal

224

Spine / spinal cord surgery

Number of cases

195
Head injury surgery
137

Others22 (16.0%)

36(18.5%)

I

II

68(30.4%)

III

118(39.7%) Endovascular therapyIVFig. 2 Changes in the number of surgical treatments and the proportion of endovascular therapy from stage I to stage
IV. The proportion of endovascular therapy to the total surgical treatments gradually increased from stage I to stage IV.
Especially from stage III to stage IV, the ratio of increase in endovascular therapy had the greatest effect on theincrease in the total surgical treatments. An: cerebral aneurysm; AVM: arteriovenous malformation; CEA: carotid endarterectomy; ICH: intracerebral hemorrhage(500.0%), acute main cerebral artery occlusions (325.0%),
Stage IV unruptured cerebral aneurysm (225.0%), and acutemain cerebral artery occlusions (325.0%), Stage IV unruptured
cerebral aneurysm (225.0%), and acute main cerebral artery
occlusions (100.0%). The highest DC and CR to the increasein the number of treatments was internal carotid artery stenosis(50.0% DC and 78.6% CR) in stage II, acute main cerebral
artery occlusions (36.1% DC and 40.6% CR) in stage III, andacute main cerebral artery occlusions (25.0% DC and 34.0%
CR) in stage IV.

4

Discussion
While the establishment of stroke centers was promoted
nationwide, three hospitals with different management
bases were integrated and merged to open a new hospital in
May 2018. Staff members who had been working in a completely different medical culture until then began to work
together, and 68% of all staff of our new hospital weretransferred from facilities without a full-time doctor ofneurosurgery or neurology. Therefore, it was essential toJournal of Neuroendovascular Therapy

Advance Published Date: March 22, 2021

4
4

DC and CR of mechanical thrombectomy for acute main cerebral artery occlusion are highest in stage III and stage IV. CR: contribution ratio; DC: degree of contribution; IC: internal carotid artery; IR:
Increase ratio from the previous period

34.0%
25.0%
100.0%
34
40.6%
36.1%
325.0%
17
0.0%
0.0%

1
3

0.0%

6.0%
4.4%
50.0%
9
15.6%
13.9%
500.0%
6–14.3%–9.1%

16
5–66.7%

22.0%
16.2%
91.7%
23
–12.5%–11.1%–25.0%
12
78.6%
50.0%

7

220.0%

18.0%
13.2%
225.0%
13
–9.4%
–8.3%
–42.9%
4
50.0%
31.8%

34.4%
30.6%
–21.4%–13.6%

0

–

10.0%
7.4%
73.5%
29.4%
118
22
88.9%
183.3%
6817
63.6%–33.3%
36
6
22
9

Total
Ruptured
aneurysm
Unruptured
aneurysm
Cervical IC
stenosisOther occlusive
lesionAcute main cerebral
artery occlusions

DC
Stage III
IR
n
CR
DC
Stage II
IRn
Stage In

Table 3 Increasing ratio, DC, and CR of endovascular treatment for major cerebrovascular disorders from stage I to stage IV

CR

n

IR

Stage IVDCCR

InStSaS IeIISt oI StIoSe IaIe at tIe StIoSe IenteI Sn a IeI SoIIStaS

hold study sessions and conferences to educate staff in thehospital and build a cooperative environment.
Before the new hospital opened, the Kuwana West Medical
Center, where neurosurgery was working full time, was incharge of the rotation only once a week. On other days, stroke
patients were transferred to other hospitals. Therefore, eventhe patient who made an emergency call within the time wastransferred to another facility, and after being diagnosed witha stroke, was transferred to the Kuwana West Medical Center.
After opening, our new hospital was in charge of about half ofa week. However, it was required to operate a stroke hotline
so that it could respond promptly to stroke patients 365 days ayear. The stroke hotline of our center started operation with the
emergency team of Kuwana City Fire Department. Kuwana
City Fire Department has jurisdiction over Kuwana City, Inabe
City, Kisozaki Town, and Toin Town. For an area of 394.93
km2 and a target population of approximately 220000, ambulance team are conducting emergency activities based on threefire stations and five branch stations. There are various prehospital stroke evaluation methods. Cincinnati Prehospital
Stroke Scale (CPSS)6) and Kurashiki Prehospital Stroke
Scale (KPSS)7) are especially well known to the ambulancecrew of Kuwana City Fire Department, and CPSS has beenused for emergency activities in this area. Considering thisprocess, we have devoted efforts to the effective operation of
the stroke hotline using CPSS.
After the opening of the new hospital, the number of
inpatients increased sharply, and the proportion of patientswith cerebrovascular diseases increased. Table 1 and Fig. 1
show that increased inpatients with cerebrovascular diseases
is the main reason for the surge in total inpatients number instage IV. As expected, the number of total surgical treatments for cerebrovascular diseases increased in an unfamiliar environment with inexperienced staff and a limited
number of beds. Comparing the proportions, the increase inendovascular therapy clearly had the greatest impact on thetransition of the total number of surgical therapy.
Because of low invasiveness and efficacy, the number ofendovascular treatments steadily increased from stage I tostage IV. It was considered that the rapid increase in endovascular therapy in stage IV was due to the improvement ofemergency transport and medical care system with the startof the stroke center. Among the increasing number of endovascular treatments, the one with the highest DC and CR
was mechanical thrombectomy. The significant increase instage IV was considered to be the result of an increase incases that were delivered in time via the stroke hotline.
In addition, improvement of emergency transport system

5

Journal of Neuroendovascular Therapy

Advance Published Date: March 22, 2021

SaSaSSa SS et aS.

Total

Ruptured aneurysm

118

Unruptured aneurysm

Number of cases

RA
UA
AVM
dAVF
BT

68

22
17

ICS

36

OOL

22

13
9

7

6

AAO

4
0

Others

I

II

III

IV

I

Cervical IC stenosis

II

III

IV

Other occlusive lesion

I

II

III

IV

Acute main artery occlusion
34

Number of cases

23
17

16
12
5

I

3
II

III

IV

I

6

9
4

4

I

II

1
II

III

IV

III

IV

Fig. 3 Transition of endovascular therapy from stage I to stage IV.
Endovascular therapy for major cerebrovascular diseases tended toincrease on average, and mechanical thrombectomy for acute main
artery occlusion increased remarkably. AAO: acute main cerebral artery

occlusions; AVM: arteriovenous malformation; BT: brain tumor; dAVF:
dural arteriovenous fistula; IC: internal carotid artery; ICS: internal carotid
artery stenosis; OOL: other intracranial/extracranial occlusive lesions;
RA: ruptured cerebral aneurysm; UA: unruptured cerebral aneurysm

and triage capacity of ambulance team, education of hospital staff and reformation of in-hospital system, and enlightenment activities for citizens were affected. Mechanicalthrombectomy is the most important function required for astroke center, and our result is considered to have shown theeffect and validity of investing medical resources to open astroke center. The expansion of indications according to theresults of DAWN trial8) also has an effect. Stroke medical
systems are now required to have more detailed diagnostic
capabilities for images. In that sense, the establishment of a

stroke center is of great significance because it is necessary
to gather a large number of specialized staff members andprepare a system that enables high-performance diagnostic
imaging equipment to be used at any time.
To eliminate the exhaustion of medical staff and provide
high-quality stroke care, there is a limit to the decentralized
medical care system of small to medium-scale facilities. On theother hand, Japan has a poor track record of cost-effectivenessin setting up a stroke center with expensive investment andgreat effort. Because our center has just opened, it is unknown

6

Journal of Neuroendovascular Therapy

Advance Published Date: March 22, 2021
InStSaS IeIISt oI StIoSe IaIe at tIe StIoSe IenteI Sn a IeI SoIIStaS

whether the burden on stroke medical staff could be reduced.
However, it is considered that the effect for acute stroke treatment was higher than expected, in spite that the operation of
our stroke center was started with unique and special circumstances. Our stroke center was approved as the Japan Stroke
Society’s Primary Stroke Center in September 2019, and further advancement is essential to improve the treatment outcome of acute stroke patients.

References
1)

2)

3)

Conclusion
With the establishment of a stroke center, the regional
stroke medical system improved and the number of casesof acute cerebral infarction within the adaptation time who
were able to receive mechanical thrombectomy remarkably increased. The results showed the effectiveness andsignificance of opening a stroke center by consolidating
human resources and medical functions.

Acknowledgment
The authors thank Dr. Takeshi Okada, a new member ofour stroke center, for his help in data analysis.

Disclosure Statement
All authors have no conflict of interest.

4)

5)

6)

7)
8)

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