Sage Journals: Discover world-class research

Abstract

Background and Purpose

Rapid treatment is a major determinant of outcome in acute ischemic stroke patients with large vessel occlusion. We used patient-level data from the ESCAPE and ESCAPE-NA1 trials to evaluate whether and to what extent workflow interval times have improved over time.

Methods

Data were derived from the ESCAPE and the ESCAPE-NA1 randomized trials. Workflow interval times and reperfusion quality were summarized using descriptive statistics and compared on a patient level between the two trials using the Wilcoxon rank sum test and Fisher's exact test. The effect of patient baseline characteristics, including patient age, sex and stroke severity as measured by the National Institutes of Health Stroke Scale, on workflow times was determined using linear regression.

Results

All patients from the ESCAPE trial (n = 315) and the ESCAPE-NA1 trials (n = 1105) were included in the analysis. For endovascular interval times, control patients from the ESCAPE trial were excluded. All in-hospital workflow interval times, including door-to-reperfusion times, were significantly shorter in ESCAPE-NA1 (median 91 min [IQR 69–120] vs. 110 [IQR 89–143], P < .001). These improvements were mainly observed in patients directly presenting to an EVT-capable hospital. Onset-to-randomization times did not differ significantly between the two trials (ESCAPE-NA1: median 188 [122–319] vs. ESCAPE: 174 [119–285], P = .152). There was no effect of procedural sedation use, age, sex, stroke severity or evidence of a learning effect over the duration of each trial.

Conclusion

Workflow interval times in endovascular stroke treatment have significantly improved over time, particularly in patients directly presenting to an EVT-capable hospital.

Keywords

Stroke thrombectomy systems of care acute ischemic stroke large vessel occlusion stroke

Introduction

The overarching goal in endovascular stroke treatment (EVT)^1,2 is to open the occluded artery fast and completely. Reperfusion speed is a major determinant of outcome that can be influenced by the stroke intervention team.^1,3 Faster treatment is strongly associated with better outcomes^4–7 and lower overall costs of stroke treatment,^8,9 and therefore, interval times are an important process measure outcome used to assess the quality of acute stroke care. Thus, stroke physicians and their medical teams have worked hard towards achieving faster treatment times, by introducing pre-notification tools, optimizing transport paradigms¹⁰ and streamlining in-hospital workflows.^11–14,15 Both the ESCAPE and ESCAPE-NA1 trials^16,17 emphasized workflow speed. ESCAPE had the shortest workflow times compared to other EVT trials.^18–22

We compared workflow interval times and endovascular reperfusion results from the ESCAPE trial (enrolment period February 2013 to October 2014), to ESCAPE-NA1 (enrolment period: March 2017 to August 2019) to compare interval times according to their modality of arrival (transfer vs. direct) and to evaluate improvement in workflow interval times.

Methods

Data are from the ESCAPE and the ESCAPE-NA1 trials. The ESCAPE trial (NCT01778335) was a multicenter randomized controlled trial comparing EVT in addition to the best medical treatment to the best medical treatment alone for AIS patients with LVO.¹⁶ Patients were eligible for the trial if they presented within 12 h of symptom onset.²³ In total, 316 patients (n = 165 in the EVT arm and n = 150 in the control arm, 1 patient was excluded due to improper consent) were enrolled at 22 sites (Canada, United States, Ireland, UK, South Korea) between February 2013 and October 2014. The ESCAPE-NA1 trial (NCT02930018) was a multicenter randomized, double-blinded, placebo-controlled trial that evaluated the efficacy and safety of nerinetide (NA1) in patients with acute ischemic stroke due to LVO that underwent EVT.²⁴ EVT patients who presented within 12 h from symptom onset were randomized to a single, 2.6 mg/kg dose of intravenous nerinetide or saline placebo. In total, 1105 patients (n = 549 in the Nerinetide arm and n = 556 in the placebo arm) were enrolled at 48 sites (Canada, United States, Ireland, Germany, Sweden, UK, South Korea, Australia) between March 2017, and August 2019. Both trials included patients who were assessed directly at a study EVT centre as well as patients who were initially referred to a primary hospital and then transferred for EVT. Clinical and neurovascular imaging inclusion and exclusion criteria were similar in both trials.^16,17 The ESCAPE-NA1 imaging criteria were slightly more inclusive, with a lower Alberta Stroke Program CT Score (ASPECTS) threshold of ≥5, compared to a threshold of ≥6 in the ESCAPE trial.

The two trials collected data on multiple workflow interval times. Hospital arrival was defined as arrival at the emergency department of the endovascular-capable hospital. Baseline imaging time was defined as the time of the first slice of non-contrast head CT of the qualifying imaging which was performed at the EVT-capable hospital. Reperfusion time was defined as the time of first modified treatment in cerebral infarction (mTICI)³ score of 2b or higher, as seen on digital subtraction angiography. The first and final reperfusion results were assessed by an independent core lab. In the ESCAPE trial, transfer patients were defined as those who received intravenous alteplase prior to arrival at the EVT hospital. Mothership patients were those who arrived directly at the EVT hospital. In the ESCAPE-NA1 trial, patients were classified as ‘transfer’ or ‘mothership’ primarily, regardless of where intravenous alteplase was administered.

Statistical analysis

Data are summarized using descriptive statistics. Workflow metrics and reperfusion results were compared between the two trials using the Wilcoxon rank sum (Mann–Whitney U) test and Fisher's exact test. We investigated predictors of the summary in-hospital metric, door-to-puncture time using multiple linear regression. All tests were two-sided and conventional levels of significance (alpha = .05) were used for interpretation. Data analyses were performed in Stata 16.1.

Results

Baseline characteristics are shown in Table 1. Key differences between the two trials were the higher proportion of patients arriving by transfer from a primary hospital, higher general anaesthesia use and lower alteplase use in the ESCAPE-NA1 trial. Distributions for interval times are shown in Supplemental Figures I–III.

Table 1.

Baseline characteristics.

Demographic	ESCAPE trial (n = 315)	ESCAPE-NA1 trial (n = 1105)
Age (median, iqr)	71 (60–81)	71 (61–80)
Female sex	150 (47.6%)	556 (50.3%)
NIHSS baseline	17 (13–20)	17 (12–21)
Alteplase use	238 (75.6%)	659 (59.6%)
Procedural sedation^a
None	75 (45.7%)	233 (21.1%)
Conscious sedation	74 (45.1%)	679 (61.5%)
General anaesthesia	15 (9.2%)	192 (17.4%)
Arrival direct	260 (85.0%)	642 (58.1%)
High enrolling site (>30 patients)	163 (51.8%)	632 (57.2%)
Region
Canada	202 (64.1%)	505 (45.7%)
US	75 (23.8%)	414 (37.5%)
Europe	38 (12.1%)	101 (9.1%)
Australasia	0 (0%)	85 (7.75)

ESCAPE trial included 165 in the treatment group.

IQR = interquartile range.

Workflow interval times from both trials are shown in Table 2, and by mode of hospital arrival in Table 3. Except for onset-to-randomization time, all interval times were significantly shorter in ESCAPE-NA1, suggesting clear improvement in in-hospital workflows over 5 years (Table 2). In-hospital process times at the EVT-capable hospital were generally faster in transfer patients compared to direct arrival (mothership) patients (Table 3). A comparison of workflow times in transfer vs. mothership patients showed that the largest improvements were made in mothership patients, while the differences in interval times in transfer patients were less pronounced (Table 3). In fact, in transfer patients, some interval times were longer in ESCAPE-NA1 compared to ESCAPE (door-to-imaging time: median 12 [7–19] min in ESCAPE-NA1 vs. 9.5 [5–19] min in ESCAPE, door-to-puncture time: 48 [37–68] min vs. 46. [32–64] min, imaging-to-puncture time: 36 [26–53] min vs. 32 [24–48] min).

Table 2.

Workflow interval times in ESCAPE and ESCAPE-NA1 trials.

Interval time (minutes, median with IQR)	ESCAPE trial	ESCAPE-NA1 trial	P
Onset to randomization	174 (119–285)N=314	188 (121.5–310)N=1104	.1523
Door to imaging	19 (11–29)N=306	13 (8–19)N=1104	<.0001
Door to alteplase	35 (16–52)N=230	21 (−61–34)^aN=656	<.0001^a
Door to puncture	76 (62–103)N=157	59 (42–84)N=1101	<.0001
Door to reperfusion	110 (89–143)N=142	91 (69–120)N=1009	<.0001
Imaging to puncture	51 (39–68)N=161	45 (30–65)N=1101	.0010
Imaging to reperfusion	84 (65–115)N=145	76 (57–101)N=1009	.0029
Puncture to reperfusion	30 (18–45.5)N=144	25 (17–39)N=973	.0855

Note. Interpretation of interval times.

Door = arrival at ED of comprehensive (EVT) stroke centre; imaging = time of first slice of non-contrast CT of the qualifying imaging; alteplase = time of intravenous alteplase bolus dose (applies to patient receiving alteplase only); puncture = time of arterial access for EVT; reperfusion = time of reperfusion (eTICI 2b score or higher, patients who received EVT only); IQR = interquartile range; ED = emergency department; EVT = endovascular thrombectomy; CT = computed tomography; eTICI = expanded thrombolysis in cerebral ischemia score

Negative times here indicate the fact that alteplase was dosed at an outside hospital before transfer.

P-values refer to the test of the hypothesis that the distribution of times is not equal between trials using the Mann–Whitney U test.

Table 3.

Workflow interval times in direct vs. transfer patients.

Interval time (minutes, median, IQR)	Direct		Transfer		P
Onset to randomization	146 (109–240)N = 900		252 (183–380)N = 509		<.0001
Door to imaging	15 (10–22)N = 901		12 (6–19)N = 509		<.0001
Door to alteplase	32 (22–45)N = 564		−74 (−112 to −21)^aN = 320		<.0001
Door to puncture	71 (52–94)N = 771		48 (36–68)N = 487		<.0001
Door to reperfusion	101 (79–128)N = 705		80 (62–110)N = 446		<.0001
Imaging to puncture	53 (38–72)N = 771		35 (26–53)N = 487		<.0001
Imaging to Reperfusion	83 (63–108)N = 705		68 (51–95)N = 446		<.0001
Puncture to reperfusion	26 (17–39)N = 689		26 (17–40)N = 425		.9184
	Direct		Transfer		P(Direct)	P(Transfer)
	ESCAPE	ESCAPE-NA1	ESCAPE	ESCAPE-NA1	ESCAPE cf ESCAPE-NA1
Onset to randomization	158 (113–253)N = 259	141 (106–237)N = 641	283 (212–383)N = 46	250 (177–380)N = 463	.1840	.2506
Door to imaging	20 (14–30)N = 260	13 (9–19)N = 641	9.5 (5–19)N = 46	12 (7–19)N = 463	<.0001	.3922
Door to alteplase	40 (30–75)N = 182	28.5 (20–40)N = 382	−95 (−157 to −66)N = 46	−70.5 (−107 to 14)N = 274	<.0001	<.0001
Door to puncture	79.5 (66–108.5)N = 132	68 (49–91)N = 639	46 (32–64)N = 25	48 (37–68)N = 462	<.0001	.6141
Door to reperfusion	112 (95–145)N = 118	99 (76–126)N = 587	93.5 (56–133)N = 24	79 (62–109)N = 422	<.0001	.5760
Imaging to puncture	54 (44.5–72.5)N = 132	53 (35–72)N = 639	32 (24–48)N = 25	36 (26–53)N = 462	.0766	.4042
Imaging to reperfusion	88.5 (67–116)N = 118	82 (62–107)N = 587	76 (40.5–117.5)N = 24	68 (51–93)N = 422	.0579	.6870
Puncture to reperfusion	30 (18–44)N = 117	25 (17–38)N = 572	33.5 (17.5–56.5)N = 24	25 (17–40)N = 401	.1711	.2166

Note = interpretation of interval times

Negative times here indicate the fact that alteplase was dosed at an outside hospital before transfer.

P-values refer to the test of the hypothesis that the distribution of times is not equal using the Mann–Whitney U test.

Predictors of improvement in door-to-puncture time are shown in Table 4. The marked difference between direct arrival and transfer patients, between the two studies over 5 years and among regions of the world, is evident. There was no effect of procedural sedation use, age, sex, stroke severity or evidence of a learning effect (change according to randomization order) over the duration of each trial.

Table 4.

Predictors of in-hospital door-to-puncture time.

Variable	Minutes slower or faster(ß coefficient)	P
Direct to mothership (vs. transfer)	18.1	<.0001
US (vs. Canada)	−0.1	.99908
Europe (vs. Canada)	−18.5	<.0001
Australasia (vs. Canada)	19.5	.0002
ESCAPE-NA1 study (vs. ESCAPE study)	−17.2	<.0001

Multiple linear regression analysis identifying predictors of door-to-puncture time in minutes, adjusted for age, sex, baseline NIHSS score, alteplase use, high volume (>30 patients enrolled) vs. low volume centre, procedural sedation type and randomization order. On average, door-to-puncture is 18 min slower with direct arrival to the EVT centre vs. transfer from a primary hospital; using Canadian sites as a benchmark, 19 min faster in Europe and 19 min slower in Australasia (Australian and South Korean sites), with no difference between the US and Canada; and 18 min faster in ESCAPE-NA1 compared to the ESCAPE trial. Clinical factors age, sex, baseline NIHSS score, alteplase use, high volume (>30 patients enrolled) vs. low volume centre, procedural sedation type and randomization order (as a surrogate marker for a protocol learning effect) were not predictive of door-to-puncture time.

Discussion

This study shows significant improvements in endovascular stroke treatment interval times over 5 years, particularly in patients directly admitted to an EVT-capable hospital.

Since 2015, pre-notification tools, one-stop-shop imaging (i.e. bypassing the CT scanner) and pre-prepared standardized thrombectomy kits (BRISK; Brisk Recanalization Ischemic Stroke Kit) for example have been introduced to minimize in-hospital delays.^13,14,25 Our results suggest that these measures have indeed been successful in minimizing in-hospital workflow times, particularly in EVT-capable hospitals. All the in-hospital workflow interval times that were assessed in this study have improved over time, which resulted in a notable decrease of almost 20 min on average in door-to-reperfusion time (median 91 [69–120] min in ESCAPE-NA1 vs. 110 [89–143] min in ESCAPE), which is arguably the most meaningful in-hospital workflow interval time. Time efficiency of in-hospital workflows improved at all levels, with significantly shorter door-to-imaging, door-to-alteplase, imaging-to-puncture and puncture-to-reperfusion-times in the ESCAPE-NA1 trial. An important neutral finding is that the use of general anaesthesia or conscious sedation did not, on average, result in longer in-hospital treatment times.

Onset to randomization times were slightly longer in ESCAPE-NA1 compared to ESCAPE. We suspect that this was caused by secular changes in stroke care with more patients being treated and enrolled into the trial in later time windows.

Overall, in-hospital process times at the EVT-capable hospital are significantly faster for patients who are transferred, probably due to the opportunity to prepare for the patient's arrival while the patient is in transit. Once the EVT procedure has begun, interval times to reperfusion are very similar in transfer and mothership patients. Improvements in interval times for transfer patients were less pronounced, with door-to-imaging, door-to-puncture and imaging-to-puncture times having even slightly increased over time. One reason for this could be that workflows and protocols for transfer patients are less standardized and also depend on the local infrastructure and referring hospitals. Limited communication and imaging transmission between hospitals play a role in longer interval times for transfer patients. Alternately, we may have reached a ceiling where substantively faster treatment is simply not possible to achieve. It is important to note that most patients in both trials underwent imaging at the endovascular centre. Bypassing this step, especially in those situations where the imaging at the outside hospital is relatively recent and there is no change in the patient's clinical status, could potentially lead to further shortening of the overall times of transfer patients. On the other hand, the COVID-19 pandemic, which started after completion of the ESCAPE-NA1 trial, has slowed down acute stroke workflow times in some instances,²⁶ and the recent increase in endovascular treatment of large core and medium vessel occlusion patients may require a more nuanced approach to decision-making compared to the LVO stroke patient population with small-to-moderate core sizes that were included in the ESCAPE and ESCAPE-NA1 trials. This may cause slight treatment delays, and a workflow comparison that includes more recent workflow data from large core and medium vessel occlusion EVT trials would thus be of interest.

The current study benefits from two large, randomized datasets that allowed for patient-level comparison of a number of workflow metrics and reperfusion quality but is limited to the sites that contributed to both trials. The external validity of the results will necessarily depend upon site-specific factors. The distinction between mothership and transfer patients in the ESCAPE trial was based on the location of intravenous alteplase administration; patients who did not receive intravenous alteplase were classified as mothership patients, even if they might have initially been admitted to another hospital. Only the EVT arm of ESCAPE was used for the comparison of reperfusion time metrics and quality, which resulted in a relatively small sample number of ESCAPE patients that were included in the comparison.

In conclusion, workflow interval times in endovascular stroke treatment have significantly improved over time, particularly in patients directly presenting to an EVT-capable hospital.

Supplemental Material

sj-docx-1-ine-10.1177_15910199251330095 - Supplemental material for Improvements in endovascular stroke treatment workflow over 5 years: ESCAPE to ESCAPE-NA1

Supplemental material, sj-docx-1-ine-10.1177_15910199251330095 for Improvements in endovascular stroke treatment workflow over 5 years: ESCAPE to ESCAPE-NA1 by Johanna M Ospel, Mayank Goyal, Ryan McTaggart, Alexandre Y Poppe, Andrew M Demchuk, J Rempel, J Thornton, Ricardo A Hanel, Mohammed Almekhlafi, Bruce CV Campbell, René Chapot, Diogo Haussen, Mahesh Jayaraman, Joung-Ho Rha, Richard H Swartz, Michael Tymianski, Bijoy K Menon, Raul G Nogueira, Michael D Hill and in Interventional Neuroradiology

Footnotes

Declaration of conflicting interests

Michael Tymianski is the founder and CEO of NoNO Inc. The remaining authors have no relevant disclosures.

Funding

The authors disclosed receipt of the following financial support for the research,authorship,and/or publication of this article: The ESCAPE trial was funded by a consortium that included industry (Covidien LLC (now Medtronic LLC)) and public sources (the University of Calgary Hotchkiss Brain Institute,Heart & Stroke Foundation of Alberta,Alberta Innovates,Alberta Health Services,and CIHR through the CSPIN Network). The ESCAPE-NA1 trial was funded by a consortium that included industry (NoNO Inc.) and public sources (CIHR and Alberta Innovates). Canadian Institutes of Health Research,NoNO Inc.,Medtronic Canada,Alberta Innovates (grant number N/A).

ORCID iDs

Johanna M. Ospel

Mayank Goyal

Supplemental material

Supplemental material for this article is available online.

References

Saver

Goyal

van der Lugt

, et al. Time to treatment with endovascular thrombectomy and outcomes from ischemic stroke: a meta-analysis. JAMA 2016; 316: 1279–1288. 2016/09/28.

Powers

Rabinstein

Ackerson

, et al. Guidelines for the Early Management of Patients With Acute Ischemic Stroke: 2019 Update to the 2018 Guidelines for the Early Management of Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2019 Dec; 50: e344–e418. DOI: https://doi.org/10.1161/STR.0000000000000211. Epub 2019 Oct 30. Erratum in: Stroke. 2019 Dec; 50: e440–e441. DOI: https://doi.org/10.1161/STR.0000000000000215

Liebeskind

Bracard

Guillemin

, et al. eTICI reperfusion: defining success in endovascular stroke therapy. J Neurointerv Surg 2019; 11: 433–438. 2018/09/09.

Bourcier

Goyal

Liebeskind

, et al. Association of time from stroke onset to groin puncture with quality of reperfusion after mechanical thrombectomy: a meta-analysis of individual patient data from 7 randomized clinical trials. JAMA Neurol 2019; 76: 405–411. 2019/01/23.

Fransen

Berkhemer

Lingsma

, et al. Time to reperfusion and treatment effect for acute ischemic stroke: a randomized clinical trial. JAMA Neurol 2016; 73: 190–196. 2015/12/31.

Mulder

Jansen

IGH

Goldhoorn

, et al. Time to endovascular treatment and outcome in acute ischemic stroke: mR CLEAN registry results. Circulation 2018; 138: 232–240. 2018/03/28.

Venema

Groot

Lingsma

, et al. Effect of interhospital transfer on endovascular treatment for acute ischemic stroke. Stroke 2019; 50: 923–930. 2019/03/14.

Kunz

Hunink

Almekhlafi

, et al. Public health and cost consequences of time delays to thrombectomy for acute ischemic stroke. Neurology 2020; 95: e2465–e2475. 2020/09/19.

Kunz

Hunink

Sommer

, et al. Cost-Effectiveness of endovascular stroke therapy: a patient subgroup analysis from a US healthcare perspective. Stroke 2016; 47: 2797–2804. 2016/10/26.

10.

Holodinsky

Williamson

Demchuk

, et al. Modeling stroke patient transport for all patients with suspected large-vessel occlusion. JAMA Neurol 2018; 75: 1477–1486. 2018/09/08.

11.

Lin

Peterson

Smith

, et al. Emergency medical service hospital prenotification is associated with improved evaluation and treatment of acute ischemic stroke. Circ Cardiovasc Qual Outcomes 2012; 5: 514–522. 2012/07/13.

12.

Mosley

Nicol

Donnan

, et al. The impact of ambulance practice on acute stroke care. Stroke 2007; 38: 2765–2770. 2007/08/25.

13.

Psychogios

Behme

Schregel

, et al. One-Stop management of acute stroke patients: minimizing door-to-reperfusion times. Stroke 2017; 48: 3152–3155. 2017/10/12.

14.

Zerna

Assis

d'Esterre

, et al. Imaging, intervention, and workflow in acute ischemic stroke: the calgary approach. AJNR Am J Neuroradiol 2016; 37: 978–984. 2015/12/15.

15.

Goyal

Ospel

. Challenges to stroke care 5 years after endovascular therapy became the standard. Lancet Neurol 2020; 19: 210–211. 2020/02/23.

16.

Goyal

Demchuk

Menon

, et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med 2015; 372: 1019–1030. 2015/02/12.

17.

Hill

Goyal

Menon

, et al. Efficacy and safety of nerinetide for the treatment of acute ischaemic stroke (ESCAPE-NA1): a multicentre, double-blind, randomised controlled trial. Lancet. 2020 Mar 14; 395: 878–887. DOI: https://doi.org/10.1016/S0140-6736(20)30258-0

18.

Goyal

Jadhav

Bonafe

, et al. Analysis of workflow and time to treatment and the effects on outcome in endovascular treatment of acute ischemic stroke: results from the SWIFT PRIME randomized controlled trial. Radiology 2016; 279: 888–897. 2016/04/20.

19.

Menon

Sajobi

Zhang

, et al. Analysis of workflow and time to treatment on thrombectomy outcome in the endovascular treatment for small core and proximal occlusion ischemic stroke (ESCAPE) randomized, controlled trial. Circulation 2016; 133: 2279–2286. 2016/04/15.

20.

Venema

Boodt

Berkhemer

, et al. Workflow and factors associated with delay in the delivery of intra-arterial treatment for acute ischemic stroke in the MR CLEAN trial. J Neurointerv Surg 2018; 10: 424–428. 2017/09/01.

21.

Bracard

Ducrocq

Mas

, et al. Mechanical thrombectomy after intravenous alteplase versus alteplase alone after stroke (THRACE): a randomised controlled trial. Lancet Neurol 2016; 15: 1138–1147. 2016/08/28.

22.

Muir

Ford

Messow

, et al. Endovascular therapy for acute ischaemic stroke: the pragmatic ischaemic stroke thrombectomy evaluation (PISTE) randomised, controlled trial. J Neurol Neurosurg Psychiatry 2017; 88: 38–44. 2016/10/21.

23.

Demchuk

Goyal

Menon

, et al. Endovascular treatment for small core and anterior circulation proximal occlusion with emphasis on minimizing CT to recanalization times (ESCAPE) trial: methodology. Int J Stroke 2015; 10: 429–438. 2014/12/30.

24.

Hill

Goyal

Menon

, et al. Efficacy and safety of nerinetide for the treatment of acute ischaemic stroke (ESCAPE-NA1): a multicentre, double-blind, randomised controlled trial. Lancet 2020; 395: 878–887. 2020/02/24.

25.

Ospel

Almekhlafi

Menon

, et al. Workflow patterns and potential for optimization in endovascular stroke treatment across the world: results from a multinational survey. J Neurointerv Surg 2020 Dec; 12: 1194–1198. DOI: https://doi.org/10.1136/neurintsurg-2020-015902. Epub 2020 Apr 6.

26.

Koge

Shiozawa

Toyoda

. Acute Stroke Care in the With-COVID-19 Era: Experience at a Comprehensive Stroke Center in Japan. Front Neurol 2021 Jan 18; 11: 611504. DOI: https://doi.org/10.3389/fneur.2020.611504.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.24 MB

0.00 MB