Adaptive Approach to Endovascular Management of Large
Vessel Occlusion During the COVID-19 Pandemic
Borna Ethan Tabibian, MD, Sasha G. Howell, MS, MD,1 Arsalaan Salehani, MD,
Ekaterina Bakradze, MD, and Mark Harrigan, MD

Introduction: The COVID-19 pandemic has resulted in unprecedented strain on thehealth care system. An adaptive strategy for the handling of thrombectomy forpatients with large vessel occlusion has evolved at our center to optimize patientcare while also minimizing risk of virus transmission. The purpose of this study
was to evaluate the effects of the new thrombectomy protocol by comparing thrombectomy times and patient outcomes during the pandemic and pre pandemic
period. Methods: A retrospective cohort study was conducted on patients who
underwent emergent thrombectomy from April 4th, 2020 to August 25th, 2020
(pandemic period) and between December 2nd, 2019 to April 3rd, 2020 (pre-pandemic period). The new protocol centered on a standardized approach to airway
management in patients considered ‘high-risk’ for infection. An array of patientspeciﬁc factors and outcomes were compared between the two groups. Results: A
total of 126 patients were included in the study. There was no signiﬁcant difference
in door-to-recanalization or other time parameters between the two groups (138minutes during the pandemic vs. 129 minutes pre-pandemic; p=0.37). However,outcomes measured as discharge modiﬁed Rankin Scale (mRS) were worse forpatients during the pandemic (mRS  2, 10/58; 17.2% during pandemic vs. 24/68;
35.3% pre-pandemic, p = 0.02). No neurointerventional providers have been foundto contract COVID-19. Conclusion: Our approach to mechanical thrombectomy during the COVID-19 era was associated with similar recanalization rates but worse
clinical outcomes compared to pre pandemic period. Further studies are necessary
to identify factors contributing to worse outcomes during this ongoing pandemic.
Key Words: Mechanical thrombectomy—Large vessel occlusion—ischemic—
stroke—COVID-19—outcomes—management© 2021 Elsevier Inc. All rights reserved.

Introduction
The COVID-19 pandemic has increased the complexityof endovascular treatment of large vessel occlusion (LVO)
in acute ischemic stroke. In response to the pandemic,
stroke centers have undergone substantial reorganization
and alterations to mechanical thrombectomy protocols.1,2
Recent studies suggest trends in increased time from hospital arrival to puncture and hospital arrival to
From the University of Alabama at Birmingham, Department of
Neurosurgery, Birmingham, AL.
Received November 9, 2020; revision received January 4, 2021;
accepted January 24, 2021.
No funding used for this research projectCorresponding author. E-mail: sghowell@uabmc.edu.
1
The authors of this paper report no conﬂicts of interest
1052-3057/$ - see front matter© 2021 Elsevier Inc. All rights reserved.
https://doi.org/10.1016/j.jstrokecerebrovasdis.2021.105642

reperfusion, despite reported reductions in acute strokecases.3 The additional time required to screen patientsand protect hospital staff against COVID-19 exposure arepotential explanations for these delays.4,8,9 However,patient transport, evaluation, and preparations for intervention during the era of a pandemic have also added topatient management complexity, which have a negative
inﬂuence on clinical outcomes.
Many institutions have proposed guidelines to streamline the interventional process for thrombectomy candidates.5 Additionally, mandated staff simulation training
has also been used to incorporate these newly establishedprotocols with the goal of improving efﬁciency.6 Despite
unprecedented demands on the emergency healthcare
services, early multidisciplinary efforts to adapt the acutestroke treatment process have resulted in maintaining
stroke quality time metrics close to pre-pandemic levels.7

Journal of Stroke and Cerebrovascular Diseases, Vol. 30, No. 5 (May), 2021: 105642

1B.E. TABIBIAN ET AL.

2

The purpose of this study was to evaluate how changes inthrombectomy management have inﬂuenced outcomes ata single comprehensive stroke center.

Methods
This is a single-center retrospective review of patients
who underwent thrombectomy for acute ischemic stroke
from April 4th, 2020 to August 25th, 2020 (pandemic
period) and between December 2nd, 2019 to April 3rd,
2020 (pre-pandemic period). These dates were chosenbecause they represented a similar overall time interval,
yielding a nearly equivalent sample size. Additionally,
April 4th signiﬁed the date in which an adjusted codestroke protocol was in effect.
Patients who presented to the emergency department,
either by emergency medical services or outside hospitaltransfer, were included in the study. Additionally, allpatients underwent emergent thrombectomy for large
vessel occlusion (limited to occlusion of the internal
carotid artery, M1 segment of the middle cerebral artery,or basilar artery). All large vessel occlusions were conﬁrmed by computed tomography (CT) angiography ofthe head. Appropriate candidates for thrombectomy were
determined by a stroke neurologist and a neuro-interventionalist based on time of symptom onset, baseline functional status, admission National Institutes of Health
Stroke Scale (NIHSS) score, favorable pre-procedural
imaging studies (CT Head without contrast and CT Perfusion), and clinical judgement.
The following patient speciﬁc variables and stroke timing metrics were collected via the electronic medical
record: age, gender, method of arrival, time of symptom
onset, intravenous alteplase administration, admission
NIHSS, site of large vessel occlusion, time from arrival tocode-stroke activation, time from arrival to imaging
obtained, time from arrival to femoral artery puncture,
time from arrival to ﬁrst attempt at thrombectomy (ﬁrstpass), time from arrival to vessel recanalization, timefrom puncture to vessel recanalization, time from lastknown-well (LKW) to recanalization, procedure performed with the use of general anesthesia or conscious
sedation, modiﬁed thrombolysis in cerebral ischemia(TICI) score, modiﬁed Rankin Scale (mRS) at the time ofdischarge, and discharge disposition. The TICI score wasfurther stratiﬁed into ‘favorable’ and ‘unfavorable’
groups; TICI score  2b was considered a favorable result.
The mRS at the time of discharge was divided into favorable and unfavorable outcomes; mRS  2 was consideredfavorable and mRS  3 was considered an unfavorable
outcome. Discharge disposition was also divided into two
categories: 1) patients discharged home or to an inpatient
rehabilitation facility; 2) patients discharged to a nursing
home, long-term acute care hospital, hospice or expired.
Institutional Review Board (IRB) approval was obtained
based on institutional protocol.

Statistical analysis
The difference in means of the two cohorts were compared utilizing a Mann-Whitney U test and categoricalvariables were compared using chi-square testing. A p-value of < 0.05 was considered statistically signiﬁcant.
Multivariate logistic regression analysis was performed todetermine independent predictors of outcome. Statisticalanalysis was performed with IBM SPSS Statistics 26 software.

Pre-pandemic protocol
Prior to the pandemic, the decision to perform thrombectomy with the use of general anesthesia versus conscious sedation was determined based on the patient’s
hemodynamic and airway stability, neurologic exam, andability to safely cooperate during the procedure. Historically, approximately half of the thrombectomies performed at our institution are done under conscious
sedation rather than general anesthesia, with no apparent
implications on discharge disposition or mortality rates.16
When GA is employed, our pre-pandemic protocol
involves intubation in the angiography suite by the anesthesia team, rather than in the emergency department by
an emergency medicine physician.

Adaptive code stroke protocol
Effective on April 4, 2020, an institutional code stroke
protocol was implemented for the evaluation of patients
presenting to the emergency department with symptomsof an acute ischemic stroke which accounted for a recent
rise in COVID-19 cases in the state of Alabama. The protocol was formulated based on a ‘Guidance Summary forLarge Vessel Occlusion in the era of COVID-19.5 The protocol was intended to protect healthcare workers frompossible COVID-19 exposure while efﬁciently preparing
and executing MT. There were no changes made in theselection criteria or pre-procedural imaging process indetermining appropriate candidates for thrombectomy.
All patients who presented with signs or symptoms ofacute ischemic stroke were treated as ‘high risk,’ or ‘person-under-investigation’ (PUI), regardless of any symptoms concerning for a concomitant COVID-19 infection. A
nasal swab COVID-19 test was obtained immediately
upon arrival. A negative pressure isolation room was prepared prior to patient arrival to the emergency department. All patients who were determined to be candidates
for thrombectomy were intubated in the emergency
department in a negative pressure isolation room. Intubation was performed by an emergency medicine physician.
The subsequent procedures were conducted under general anesthesia (GA) with involvement of the anesthesia
team. Post-intubation chest radiographs were deferred,
and appropriate endotracheal tube placement was conﬁrmed via live ﬂuoroscopy during the procedure.

ENDOVASCULAR MANAGEMENT FOR LVO DURING COVID-19

Results
A total of 126 patients were included in the study (58 in
the pandemic group vs. 68 in the pre-pandemic group).
Two patients tested positive for COVID-19 in the pandemic group (3.4%). Patient-speciﬁc variables and admission characteristics are presented in Table 1. There was no
statistically signiﬁcant difference in patient demographics
and pre-procedural characteristics.
Fewer patients were discharged with mRS  2 in the
pandemic cohort when compared to the pre-pandemic
cohort (17.2% vs. 35.3% respectively, p = 0.023). There
was a non-signiﬁcant trend toward longer door to puncture and door to ﬁrst pass times (p = 0.07) in the pandemic
group, but no signiﬁcant difference in door to recanalization time (p = 0.37). There was no statistically signiﬁcantdifference in mortality (p = 0.576), successful recanalization (TICI 2b, p = 0.728), or discharge disposition(p = 0.204) between the two cohorts (Table 2). On multivariate
logistic
regression
analysis,
admission
NIHSS  15 was an independent predictor of poor outcome deﬁned by mRS > 2 (OR 3.31, [95% CI 1.44 7.58],
p = .005).
To our knowledge, no neurointerventional or stroke
neurology personnel have contracted COVID-19 during
the interval of this study.

Discussion
This study demonstrates that through an adaptive codestroke protocol which standardizes airway management,
our institution has experienced stroke care timing metrics
similar to before the pandemic. Despite this, patient functional outcomes have been worse.
One variable that may account for the decline in ourfunctional outcomes at discharge is the elective intubation
and routine use of general anesthesia for all patients
undergoing thrombectomy during the pandemic. This
aspect of our protocol is in accordance with recent recommendations to treat all patients with unknown COVID-19
infection status as ‘high risk’, and to have a low thresholdfor elective intubation.10 Recent reports of increasing incidence of asymptomatic COVID-19 carriers have made thereliability of screening for symptoms, rather than nasal
swab testing, of pre-thrombectomy patients uncertain.11

3

In response to this, our center has classiﬁed all patients
undergoing thrombectomy as ‘high infection-risk,’ or persons under investigation (PUI). Endotracheal intubation
provides a theoretically reduced risk of infection transmission to healthcare personnel due to ventilation within aclosed circuit. Similar results are suggested by a recent
multi-institutional prospective study in which patients
who underwent thrombectomy under general anesthesia(GA) had a higher probability of in-hospital mortality andlower probability of functional independence at discharge.12 However, unlike in the present study, door-topuncture and door-to-reperfusion times were signiﬁcantly
increased in the GA group.
The standardization of airway management has streamlined pre-procedural preparations. This process has contributed to a pre-pandemic level of efﬁciency. Although
there have been national trends toward more liberal useof GA for mechanical thrombectomy (MT) in response to
the pandemic, our center’s policy of intubating all-comers
is unlike any other currently documented protocols in theliterature. The threshold for which to incorporate GA for
patients undergoing thrombectomy during the pandemic
remains a subject of debate. More speciﬁcally, Nguyen
et al. recommend conscious sedation as ﬁrst line forthrombectomy in candidates with unknown COVID-19
status, as it may minimize delays to treatment, optimize
patient outcomes, conserve ventilator and critical care bed
resources, and conserve anesthesiologist and staff exposure to the aerosolizing events of intubation and extubation.17 Recent randomized control trials suggest that there
is no signiﬁcant difference in outcomes based on the useof general anesthesia versus conscious sedation during
MT.13-15 However, anesthetic induction and maintenancewere highly controlled in these studies. During the pandemic, these variables were not consistently regulated. A
recent study reports comparable stroke outcome data to
the present study with regard to door-to-recanalization
times and discharge outcomes.7 The similarity in results
despite differences in institutional protocols suggests thatfurther studies are necessary to determine sources forpoor outcomes during an ongoing pandemic.
Limitations of this study include the single-institution
retrospective study design, lack of long-term follow up
and a small sample size which precludes the ability toTable 1. Patient demographics and admission characteristics

Mean age (years), § SD
Gender, male, N (%)
Mean Admission NIHSS (IQR)
Anterior circulation stroke, N (%)
Presented directly to the emergency department, N (%)
Transferred from other centers, N (%)
Received intravenous alteplase, N (%)

Pre-Pandemic (n = 68)

Pandemic (n = 58)

p value

65 § 12.6
43 (63.2%)
16.6 (9 22)
61 (89.7%)
20 (29.4%)
48 (70.6%)
29 (42.6%)

67 § 13.2
39 (67.2%)
15.2 (10 20)
52 (89.6%)
17 (29.3%)
41 (70.7%)27(40.3%)

0.66
0.71
0.46
0.41
0.96
0.96
0.78

B.E. TABIBIAN ET AL.

4

Table 2. Comparison of stroke management time intervals and outcomes

Door to code stroke interval*
Door to imaging interval*
Door to puncture interval*
Door to first pass interval*
Door to recanalization interval*
Puncture to recanalization interval*
LKW to Recanalization interval*
Number of patients who underwent thrombectomy under GA
Number of patients with TICI score  2b
Number of patients with discharge mRS score  2
Number of patients with favorable disposition**
Mortality

Pre-pandemic (n = 68)

Pandemic (n = 58)

p value

12 (10 14)
15 (4 26)
79 (53 86)
104 (89 120)
129 (99 157)
40 (25 67)
487 (311 577)
54 (79.4%)
57 (83.8%)
24 (35.3%)
40 (58.8%)
10 (14.7%)

7 (5 14)12 (5 16)90 (61 101)
129 (87 140)138 (123 147)
44 (23 65)
481 (367 756)
58 (100%)
50 (86.2%)
10 (17.2%)
35 (60.3%)
10 (17.2%)

0.3
0.38
0.07
0.07
0.37
0.91
0.93
0.01
0.73
0.02
0.6
0.57

*mean values reported in minutes (interquartile range);**deﬁned as discharge to home or inpatient rehabilitation, SD: standard deviation, IQR: interquartile range, LKW: last known
well, GA: General anesthesia, TICI: thrombolysis in cerebral infarction, mRS: modiﬁed Rankin scale, NIHSS: National Institutes of Health Stroke Scale.

match for patient speciﬁc comorbidities. It is unclear how
many patients had ‘false-negative’ COVID-19 screening
tests, and if this ultimately played a role in the decline inoutcomes. This distinction is important since patientswith COVID-19 and LVO who undergo successful recanalization have notably poor outcomes despite optimal
medical care.18

Conclusion
Through an adaptive code stroke protocol that standardizes airway management, our institution has experienced door-to-recanalization times similar to prepandemic metrics while minimizing risk of transmissionof the virus to neuro-interventional staff. Despite this,functional outcomes have been worse, possibly due to theroutine use of GA for all patients undergoing thrombectomy during the pandemic. With no obvious end in sightfor an ongoing pandemic, additional studies are required
to determine predictors of poor outcomes under theseunique circumstances.

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