Significance of Large Vessel Intracranial Occlusion Causing
Acute Ischemic Stroke and TIA
Wade S. Smith, MD, PhD; Michael H. Lev, MD, FAHA; Joey D. English, MD, PhD;
Erica C. Camargo, MD, MMSc; Maggie Chou; S. Claiborne Johnston, MD, PhD;
Gilberto Gonzalez, MD, PhD; Pamela W. Schaefer, MD; William P. Dillon, MD;
Walter J. Koroshetz, MD; Karen L. Furie, MD, MPH
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Background and Purpose—Acute ischemic stroke due to large vessel occlusion (LVO)—vertebral, basilar, carotid
terminus, middle and anterior cerebral arteries—likely portends a worse prognosis than stroke unassociated with LVO.
Because little prospective angiographic data have been reported on a cohort of unselected patients with stroke and with
transient ischemic attack, the clinical impact of LVO has been difficult to quantify.
Methods—The Screening Technology and Outcome Project in Stroke Study is a prospective imaging-based study of stroke
outcomes performed at 2 academic medical centers. Patients with suspected acute stroke who presented within 24 hours
of symptom onset and who underwent multimodality CT/CT angiography were approached for consent for collection
of clinical data and 6-month assessment of outcome. Demographic and clinical variables and 6-month modified Rankin
Scale scores were collected and combined with blinded interpretation of the CT angiography data. The OR of each
variable, including occlusion of intracranial vascular segment in predicting good outcome and 6-month mortality, was
calculated using univariate and multivariate logistic regression.
Results—Over a 33-month period, 735 patients with suspected stroke were enrolled. Of these, 578 were adjudicated as
stroke and 97 as transient ischemic attack. Among patients with stroke, 267 (46%) had LVO accounting for the stroke
and 13 (13%) of patients with transient ischemic attack had LVO accounting for transient ischemic attack symptoms.
LVO predicted 6-month mortality (OR, 4.5; 95% CI, 2.7 to 7.3; P⬍0.001). Six-month good outcome (modified Rankin
Scale score ⱕ2) was negatively predicted by LVO (0.33; 0.24 to 0.45; P⬍0.001). Based on multivariate analysis, the
presence of basilar and internal carotid terminus occlusions, in addition to National Institutes of Health Stroke Scale and
age, independently predicted outcome.
Conclusion—Large vessel intracranial occlusion accounted for nearly half of acute ischemic strokes in unselected patients
presenting to academic medical centers. In addition to age and baseline stroke severity, occlusion of either the basilar
or internal carotid terminus segment is an independent predictor of outcome at 6 months. (Stroke. 2009;40:3834-3840.)
Key Words: CT angiography 䡲 prognosis
A
clinician treating acute ischemic stroke is best enabled
to make clinical decisions if they have good predictive
models of clinical outcome considering all data available.
Models of clinical outcome after stroke have reported age and
stroke severity as independent predictors of clinical outcome.1–3 It is expected, however, that occlusion of large
intracranial vessels such as the basilar artery, carotid terminus, and middle cerebral artery is associated with higher
mortality and may also be expected to contribute predictive
value to models of stroke outcome. Furthermore, large artery
occlusion has been associated with a greater risk of stroke
after transient ischemic attack (TIA) and minor stroke.4 The
advent of noninvasive techniques for cerebral angiography
(CT angiography and MR angiography) allows for routine
acquisition of angiographic information on patients with
acute stroke and provides an opportunity to explore the
predictive value of vascular status on prognosis. The Screening Technology and Outcome Project in Stroke (STOP
Stroke) study was designed in part to prospectively obtain
complete head and neck CT angiography on an unselected
consecutive cohort of patients with acute stroke and with TIA
to better understand the prognostic significance of large
vessel occlusion of the intracranial vessels. In this study, we
used this information to determine whether acute angio-
Received July 6, 2009; final revision received August 13, 2009; accepted September 3, 2009.
From the Departments of Neurology (W.S.S., J.D.E., S.C.J.) and Radiology (W.P.D.), University of California, San Francisco, Calif; the Departments
of Radiology (M.H.L., G.G., P.W.S.) and Neurology (E.C.C., K.L.F.), Massachusetts General Hospital, Boston, Mass; the Department of Neurology
(M.C.), Columbia University, New York, NY; and the National Institute of Neurological Disorders and Stroke (W.J.K.), Bethesda, Md.
Correspondence to Wade S. Smith, MD, PhD, Professor of Neurology, Department of Neurology, University of California, San Francisco, 505
Parnassus Avenue, San Francisco, CA 94143-0114. E-mail [email protected]
© 2009 American Heart Association, Inc.
Stroke is available at http://stroke.ahajournals.org
DOI: 10.1161/STROKEAHA.109.561787
3834
Smith et al
Significance of Large-Vessel Intracranial Occlusion
3835
Figure 1. Diagnosis of patients in STOP Stroke
and prevalence of LVO in patients diagnosed
with stroke or TIA.
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graphic assessment provides significant prognostic information by itself and if this assessment provides additional
information beyond that of age and National Institutes of
Health Stroke Scale (NIHSS) at the time of patient
presentation.
Methods
The STOP Stroke Study is a prospective imaging-based study of
stroke outcomes completed at Massachusetts General Hospital and
the University of California San Francisco Medical Center. Patients
with suspected acute stroke who presented within 24 hours of
symptom onset to the institutions’ emergency departments and who
underwent multimodality CT/CT angiography (CTA) were approached for consent for 6-month follow-up and collection of clinical
data. Patients who were transferred to these institutions or had stroke
while hospitalized were excluded from the analysis. Both institutions
routinely used CT/CTA technology to image all suspected stroke or
TIA during the study period unless contraindications to intravenous
contrast existed. Surrogate consent was allowed for patients unable
to consent for themselves. Patients consented by surrogate were
reconsented for follow-up if they had regained capacity. The Institutional Review Boards of both institutions approved this
clinical study.
Research coordinators for both sites extracted demographic data
and data regarding the acute presentation and hospital course and
performed 6-month phone follow-up in all patients. All clinical data
available through the acute hospitalization, including imaging data,
were presented to an independent stroke neurologist who then
ascribed the final diagnosis for the patient as stroke, TIA, or not
stroke or TIA. Cases categorized as stroke or TIA were subjected to
the analysis here (2 cases of pure transient monocular blindness were
not considered as TIA in this analysis). Good outcome was defined
as a modified Rankin Scale score of ⱕ2 measured at 6 months after
the stroke.
All patients underwent brain CT imaging at 3.25-mm separation,
CTA at 1.25-mm increments from the aortic arch through the circle
of Willis, and postcontrast CT imaging. CT angiograms were
reconstructed as “thick maximum intensity projection” reconstructions. Both thick maximum intensity projection reconstructions and
CT source images were reviewed by 2 neuroradiologists blinded to
clinical outcome. Cerebrovascular vessels were divided into segments including supraclinoid internal carotid artery (ICA), first
division middle cerebral artery (M1), second division middle cerebral artery (M2), first division anterior cerebral artery (A1), second
division anterior cerebral artery (A2), basilar artery (BA), intracranial vertebral artery (VA), first division posterior cerebral artery
(P1), and second division posterior cerebral artery (P2). A neuroradiologist determined whether any of these vascular segments was
occluded. If this analysis showed no vascular occlusion, the patient
was documented as having no large vessel occlusion. If one or more
vascular segments were occluded, the case history and NIHSS score
were reviewed, and if the vascular occlusion was in the appropriate
territory to account for the clinical findings, the case was judged as
having a large vessel occlusion; otherwise, if the vascular segment
occlusion did not explain the clinical symptoms, the case was
classified as not having a large vessel occlusion.
Variables tested for prediction of good outcome and mortality
included age, gender, ethnicity/race, prior stroke/TIA, hypertension,
diabetes, atrial fibrillation, coronary artery disease, peripheral vascular disease, hypercholesterolemia, current tobacco use, and presence of segmental vascular occlusion. Use of intravenous tissue
plasminogen activator (tPA) or use of endovascular intervention,
including intra-arterial (IA) tPA, was not included in the primary
model nor were other therapies given during hospitalization because
the goal of the model was to best understand prognosis based on
initial presenting signs and symptoms. However, analysis of outcomes with and without use of intravenous tPA was performed in a
secondary model.
Variables were analyzed by univariate and then multivariate
modeling using Stata, Version 10 (College Station, Texas). Multivariate modeling included any variable found to have P⬍0.20 in
univariate testing with stepwise elimination by highest probability
value and variables retained with P⬍0.05.
Results
Over a 33-month period, 1636 patients were admitted to the
study hospitals with presumed stroke or TIA and 741 patients
were enrolled in the STOP Stroke study. Of these 741
patients, 5 had missing NIHSS scores, and one was missing a
final diagnosis, yielding 735 patients for further analysis
(Figure 1). After review of all clinical, laboratory, and clinical
data, an independent stroke neurologist determined that 578
patients had stroke (79%), 97 (13%) had TIA, and 60 (8%)
did not have either stroke or TIA. Of the 675 patients with
stroke/TIA, 6-month modified Rankin Scale scores were
available in 607. Demographics, risk factors, and stroke
classification for the patients with stroke and those with TIA
are shown in Table 1.
Large vessel occlusion was responsible for 267 (46%)
strokes, 13 (13%) TIAs, and 41% of stroke and TIA combined. The locations of vascular occlusion and mean NIHSS
score are shown in Table 2. The overall mean NIHSS was 7.6.
Patients with small vessel occlusions had a significantly
lower NIHSS score than patients with large vessel occlusion
(P⬍0.0001, Wilcoxon test); the presence of large vessel
occlusion was associated with a significant 7.8-point increase
in NIHSS score. There was a wide variation in NIHSS scores
based on vascular location with carotid terminus and basilar
occlusions having the highest NIHSS scores and more
distal occlusions (M2, A2, P2) having lower NIHSS
scores. Intravenous tPA was given to patients with higher
3836
Stroke
December 2009
Table 1. Demographics, Vascular Risk Factors, Etiology, and
Treatment of Patients With Stroke and Those With TIA
Table 2. NIHSS Scores of Patients With Stroke and Those With TIA
at Presentation for Each Location of Vascular Occlusion
Patients with stroke or patients with TIA, N
Vascular Location
675
N (%)
NIHSS, Mean⫾SD
Age, mean⫾SD, years
68.6⫾15.3
All patients
675 (100%)
7.63⫾7.29
Female
323 (48%)
Any large vessel
280 (41%)
12.2⫾7.82
No large vessel
395 (59%)
4.37⫾4.68
43 (6.3%)
16.2⫾6.98
Risk factors
Hypertension
415 (62%)
ICA
Diabetes mellitus
122 (18%)
M1
119 (18%)
13.4⫾6.39
Coronary artery disease
155 (23%)
M2
136 (20%)
11.5⫾6.74
Congestive heart failure
46 (6.8%)
A1
2 (0.3%)
8.50⫾3.54
Peripheral vascular disease
25 (3.7%)
A2
7 (1.0%)
12.4⫾5.13
Hyperlipidemia
193 (29%)
BA
14 (2.1%)
17.1⫾12.8
Smoking
207 (31%)
VA
16 (2.4%)
8.43⫾11.4
Atrial fibrillation
145 (22%)
P1
8 (1.2%)
16.3⫾14.0
P2
9 (1.3%)
10.4⫾6.25
Intravenous tPA
109 (16%)
13.7⫾6.28
No intravenous tPA
566 (84%)
6.46⫾6.88
Baseline Rankin score
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0
476 (71%)
1
78 (12%)
2
51 (7.6%)
3
40 (5.9%)
4
15 (2.2%)
5
Not recorded
4 (0.6%)
11 (1.6%)
SSS-TOAST stroke etiology
Cardioembolic
262 (39%)
Large artery
111 (17%)
Small vessel
63 (9.4%)
Other mechanism
49 (7.3%)
Undetermined
More than one mechanism
40 (5.9%)
Cryptogenic embolic
56 (8.3%)
Cryptogenic not embolic
70 (10%)
Incomplete workup
23 (3.4%)
Missing data
1 (0.1%)
Treatment
Intravenous tPA
109 (16%)
IA treatment
36 (5.3%)
Intravenous and IA treatment
18 (2.7%)
SSS-TOAST indicates Stop Stroke Study–TOAST.
NIHSS scores at baseline, but there were no differences in
age or vascular distribution in those who did or did not
receive intravenous tPA.
NIHSS scores showed considerable overlap between patients without large vessel occlusion and those with one, 2, or
3 intracranial vascular segments occluded (Figure 2). The
mean scores between each category of large vessel occlusion
(shown as a horizontal bar for each category in Figure 2) were
significantly higher than scores from patients with a normal
CTA (P⬍0.0001, Wilcoxon test for each comparison), and
the mean scores for 3 vascular segment occlusions was higher
than those of single segment occlusions (P⫽0.018). However, for any particular range of NIHSS scores, there was
considerable overlap between patients with a normal and
abnormal CT angiogram, suggesting that vascular status may
provide additional information to patient prognosis beyond
NIHSS alone. To better illustrate this, the presence of large
vessel occlusion was compared with the proportion of good
outcomes and mortality across various NIHSS strata (Figure 3). Good outcome was significantly influenced within
higher ranges of baseline NIHSS scores (ⱖ20), and mortality
was marginally influenced for more severe strokes. The
specific strata were chosen to allow direct comparison with
prior reports of outcomes.5,6
Clinical outcomes are shown in Table 3 for the overall
cohort by demographic, risk factor, and various categories of
vascular occlusion. Age, baseline NIHSS score, and gender
were strongly predictive of proportion of good outcome and
mortality on univariate analysis as were several risk factors.
The presence of large vessel occlusion was associated with
4.5-fold increased odds of death (95% CI, 2.7 to 7.3;
P⬍0.001) compared with patients who had a normal CT
angiogram. The absence of large vessel occlusion was associated with 3.1-fold increased odds of having a good outcome
(95% CI, 2.2 to 4.2; P⬍0.001) compared with patients with a
CTA showing large vessel occlusion (LVO). Vascular segments that were significantly associated with outcome include the ICA, M1, M2, and BA; P1 occlusions correlated
with good outcome but not mortality. Only one in 4 patients
with ICA or BA occlusions had a good clinical outcome,
whereas 34% of M1 and 40% of M2 occlusions had a good
outcome. BA occlusions were associated with a 50% mortality followed by ICA occlusion (35%) and M1 and M2
occlusions (24% each). Occlusions of the VA, A1, A2, and
P2 segments were not associated with either proportion of
good clinical outcome or mortality.
To explore the potential independent influence of large
vessel occlusion on stroke outcome, all variables available at
hospital admission (ie, not including intravenous or IA
treatment or intensive care unit-based treatments) with
P⬍0.20 on univariate analysis were tested in a multivariate
model to predict good outcome and mortality. These results
are shown in Table 3. Younger age, male gender, and lesser
Smith et al
Significance of Large-Vessel Intracranial Occlusion
3837
Figure 2. Distribution of baseline NIHSS
scores for patients with 0, 1, 2, or 3 vascular segments occluded on initial CT
angiogram. The horizontal bar indicates
the mean of the NIHSS score for each
category.
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stroke severity were positive predictors of good outcome, but
occlusion of any particular intracranial vascular segment was
not found to predict good outcome independently. ICA and
BA in combination did independently predict proportion of
good outcomes with an OR of 0.18 (P⫽0.039). Interaction
was identified between baseline NIHSS score and ICA and
BA occlusions (but not age or gender) confirming that
knowledge of these locations of vascular occlusion is most
informative at higher NIHSS scores as suggested by the
univariate analysis shown in Figure 2 and Table 2. Age and
NIHSS score were strongly predictive of mortality, but no
single vascular segment predicted mortality independently
when considered in isolation or in combination. Ordinal
logistic analysis using 3 modified Rankin Scale outcomes (0
to 2, 3 to 5, 6) found only the presence of LVO predicted
outcome (coefficient 2.7, P⫽0.006) and not age or baseline
NIHSS considering the most severe strokes (NIHSS ⱖ20),
supporting the findings shown in Figure 3.
The use of intravenous tPA was associated with good
outcome when added to the model in Table 3. Specifically,
good outcome was best modeled as age (OR [P]; 0.97
[⬍0.001]), NIHSS (0.84 [⬍0.001]), female (0.56 [0.002]),
and intravenous tPA use (2.0 [0.010]). Intravenous tPA use
did not influence mortality. If one explores the influence of
LVO in patients who did versus did not receive intravenous
tPA, occlusion of the BA and ICA vessels was negatively
predictive of good outcome for patients who received intravenous tPA but not in those who were left untreated (Table 4). This analysis is likely confounded by marked differences in baseline NIHSS scores (Table 2) so this analysis
should be considered cautiously. Use of IA therapies was so
infrequent that this variable was not considered in overall
models of outcome.
Discussion
Large vessel occlusion accounted for 46% of acute strokes in
our study. This proportion is likely a reasonable measure of
the true burden of large vessel stroke in an urban multiethnic
US population because the data were obtained from 2
geographically separate urban centers. Knowledge that a
patient has a LVO on acute presentation appears to be
important. We found that presence of LVO was associated
with a 4.5-fold increased odds of death and a 3-fold reduction
in odds of good outcome. Ordered from worse outcome to
best, BA, ICA, M1, and M2 occlusions were significantly
associated with patient mortality and decreased probability of
good outcome. The presence or absence of LVO likely adds
independent information about prognosis, especially among
patients with more severe strokes. Therefore, angiographic
imaging appears to provide an additional independent variable beyond age and baseline NIHSS score to predict patient
outcome when considering all information available to the
treating physician at patient presentation.
Nearly half of all patients with acute stroke and those with
TIA in our study were found to have occlusion of at least one
intracranial vascular segment. Other studies have found a
lower rate based on retrospective reviews of consecutive
patients; of 865 consecutive patients with stroke and those
with TIA imaged with CTA, 239 (28%) had a LVO7 and in
133 patients with suspected posterior circulation stroke, 44
(33%) had BA or VA occlusion using CTA.8 We also
observed a LVO rate of 14% for TIA. Patients with TIA with
LVO have been found to have a 40% higher rate of second
stroke than those with a normal MR angiogram9 suggesting
that these findings on CTA, even for TIA, may be clinically
important.
This estimate of 28% to 46% large vessel stroke proportion
is important when one considers the growing use of endovascular techniques that specifically target these lesions. To
properly triage patients to endovascular therapy, patients with
LVO need to be rapidly identified. We found that stroke
severity alone as measured by the NIHSS appears to be only
a modest predictor of LVO as shown in Figure 2. For any
3838
Stroke
December 2009
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Figure 3. Influence of LVO within NIHSS strata on probability of
good outcome (A) and mortality (B).
particular NIHSS score, the ability to predict occlusion of a
single or multiple intracranial vascular segments appears
limited, suggesting that the proper triage of patients to
endovascular intervention should be informed with noninvasive angiography like CTA.
Patient outcomes from large vessel stroke have not been
previously measured in a prospective cohort of consecutively
imaged patients with standardized assessment of stroke severity and outcome. One retrospective study of 226 consecutive patients undergoing conventional angiography found
NIHSS score for various LVO similar to our study in which
patients with BA and ICA occlusions had the highest NIHSS
scores and M2 occlusions the least.10 We found a striking
dependency of mortality and proportion of good outcomes
based on the simple presence or absence of a LVO. The
location of the vascular occlusion is important in that ICA,
BA, M1, and M2 occlusions were significantly correlated
with both mortality and good clinical outcome, whereas more
distal occlusions (A2, P2 vessels) were not. At least one
conventional angiographic series has shown that a normal
angiogram portends a good prognosis,11 and another retrospective study of stroke outcomes showed that proximal LVO
was associated with a more than 7-fold odds of unfavorable
outcome.12 It is well established that BA occlusions are
highly morbid as are ICA terminus lesions.13–15 Our analysis
shows that the combination of either BA or ICA occlusion
was independently associated with clinical outcome in multivariate analysis—likely for strokes with NIHSS score in
excess of 19 — further suggesting that angiographic status of
vessels is informative at the time of hospital presentation.
Less information is available about M1 and M2 occlusions,
but it has been shown previously that patients with M2
occlusion have lower NIHSS scores than M1 occlusions.10
The relative impact, however, of one vascular segment
occlusion compared with another has not been previously
reported and the data reported here may be useful to estimate
the prognosis of patients presenting with any particular CTA
finding.
Previous multivariate models of stroke prognosis that
considered variables available at the time of initial evaluation
have shown independence of age and baseline neurological
examination,2,16 and age, neurological examination, and baseline imaging (without angiography).1 We confirmed the
finding that age and NIHSS score overpower other clinical
characteristics, including vascular risk factors (Table 4).
However, our data suggest that angiographic status of
intracranial vessels at presentation confers additional prognostic information based on several lines of evidence. First,
although NIHSS score and angiographic vascular occlusion
are highly correlated, there is significant overlap in NIHSS
scores in patients with and without LVO (Figure 2). Because
LVO by itself is predictive of outcome, angiographic assessment appears to provide additional information to further
refine prognosis in patients with similar age and NIHSS
score, specifically at higher stroke severity. Second, clinical
trials that have selected patient eligibility by angiography
have shown wide variation in NIHSS scale scores despite
identical vascular segment occlusions.5,6 For example, the
NIHSS scores ranged from 4 to 30 in Prolyse in Acute
Cerebral Thromboembolism (PROACT-II) despite the fact
that all patients had documented M1 or M2 occlusion
angiographically.6 Third, we found that the extent of vascular
occlusion is related to stroke severity (Figure 2). Lastly, the
combination of BA or ICA occlusions alone was found to be
an independent predictor of clinical outcome.
The patient data included in this model are reflective of
academic, urban hospitals that have comprehensive stroke
centers (high emphasis on intravenous tPA use and optional
endovascular therapy). How reflective these patients are of
stroke treatment in general is unclear. We chose to model our
outcomes based on the information available at the time a
physician needs to make a decision regarding therapy; this
includes demographic information, their NIHSS score, and
the CTA findings. This model assumes that patients who are
considered eligible for intravenous tPA do receive it and that
a minority of patients (5.3% in our cohort) do go on to have
endovascular treatment. Our model cannot be used to predict
how a population of patients who would have been eligible
for intravenous tPA would do if not treated because the
underlying data were observational. Our models of stroke
outcome derived from these data therefore likely underestimate the impact of stroke because 18.5% of our patients
Smith et al
Table 3.
Significance of Large-Vessel Intracranial Occlusion
3839
Univariate and Multivariate Model of Good and Mortal Outcome for Stroke and TIA
Good Outcome (mRS ⱕ2)
Mean (SD) or
N (%)
Mortality
Univariate OR
(P Value)
Multivariate OR*
(P Value)
Mean (SD) or
N (%)
Univariate OR
(P Value)
Multivariate OR†
(P Value)
All patients
363 (54%)
Age, years
65 (15)
0.96 (⬍0.001)
0.97 (⬍0.001)
75 (13)
90 (13%)
1.04 (⬍0.001)
1.03 (0.001)
Female
143 (44%)
0.48 (⬍0.001)
0.59 (0.002)
54 (17%)
1.76 (0.014)
1.29 (0.320)
NIHSS score
4.7 (4.8)
0.86 (⬍0.001)
0.86 (⬍0.001)
16 (9.2)
1.17 (⬍0.001)
1.17 (⬍0.001)
Risk factors
Hypertension
205 (49%)
0.63 (0.004)
0.86 (0.503)
67 (16%)
1.98 (0.007)
1.40 (0.267)
Diabetes mellitus
56 (46%)
0.68 (0.055)
0.73 (0.165)
23 (19%)
1.68 (0.049)
1.74 (0.071)
Coronary artery disease
75 (48%)
0.76 (0.126)
0.78 (0.270)
30 (19%)
1.84 (0.013)
1.51 (0.154)
Congestive heart failure
13 (28%)
0.31 (0.001)
0.78 (0.520)
16 (35%)
4.00 (⬍0.001)
1.68 (0.181)
Peripheral vascular disease
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9 (36%)
0.47 (0.075)
0.59 (0.280)
4 (16%)
1.25 (0.690)
0.83 (0.766)
Hyperlipidemia
108 (56%)
1.13 (0.472)
1.23 (0.293)
22 (11%)
0.78 (0.350)
0.73 (0.287)
Smoking
131 (63%)
1.75 (0.001)
1.38 (0.101)
21 (10%)
0.65 (0.107)
0.83 (0.545)
57 (39%)
0.47 (⬍0.001)
0.92 (0.723)
33 (23%)
2.45 (⬍0.001)
1.10 (0.742)
Any large vessel (N⫽280)
106 (38%)
0.33 (⬍0.001)
0.82 (0.364)
65 (23%)
4.47 (⬍0.001)
1.42 (0.260)
No large vessel (N⫽363)
Atrial fibrillation
Vessels
257 (65%)
3.06 (⬍0.001)
1.21 (0.364)
25 (6.3%)
0.22 (⬍0.001)
0.71 (0.260)
ICA (N⫽43)
8 (19%)
0.18 (⬍0.001)
0.47 (0.097)
15 (35%)
3.98 (⬍0.001)
1.27 (0.557)
M1 (N⫽119)
41 (34%)
0.38 (⬍0.001)
0.92 (0.752)
28 (24%)
2.45 (⬍0.001)
1.12 (0.701)
M2 (N⫽136)
54 (40%)
0.49 (⬍0.001)
1.00 (0.986)
32 (24%)
2.55 (⬍0.001)
1.45 (0.187)
A1 (N⫽2)
1 (50%)
0.86 (0.915)
0.40 (0.524)
0 (0%)
A2 (N⫽7)
2 (29%)
0.34 (0.199)
0.81 (0.824)
0 (0%)
BA (N⫽14)
3 (21%)
0.23 (0.024)
0.40 (0.243)
7 (50%)
6.96 (⬍0.001)
2.69 (0.175)
VA (N⫽16)
10 (63%)
1.40 (0.481)
1.19 (0.790)
4 (25%)
2.22 (0.175)
3.12 (0.142)
P1 (N⫽8)
1 (13%)
0.12 (0.048)
0.14 (0.084)
2 (25%)
2.19 (0.341)
0.53 (0.663)
P2 (N⫽9)
2 (22%)
0.24 (0.078)
0.34 (0.208)
0 (0%)
0.18 (⬍0.001)
0.44 (0.039)
22 (39%)
2.36 (⬍0.001)
1.60 (0.215)
BA or ICA (N⫽57)
11 (19%)
*Final model included age, gender, and NIHSS score; values shown for other variables are for the individual variable added alone to the final model.
†Final model included age and NIHSS score; values shown for other variables are for the individual variable added alone to the final model.
mRS indicates modified Rankin Scale.
received intravenous or IA or combined intravenous/IA
treatment with thrombolytics. However, the database used to
create this model approximates a population-based study in
that patient eligibility was broad (suspected stroke, ⬍24
hours, multimodality CT/CTA performed) and both hospitals
used multimodality CT/CTA as their standard acute imaging
protocol in all patients with stroke except those with known
renal failure. Because all patients who died were included,
but not all patients who survived (or their surrogate) gave
Table 4.
Influence of Intravenous tPA on Models of Outcome
Treatment
Good Outcome (mRS ⱕ2)
Age: 0.97 (0.045)
IV tPA: OR (P)
Mortality
N
NIHSS: 1.08 (0.055)
109
Age: 1.04 (0.002)
566
NIHSS: 0.89 (0.005)
BA or ICA: 0.19 (0.045)
Age: 0.97 (⬍0.001)
No IV tPA: OR (P)
Female: 0.57 (0.005)
NIHSS: 1.20 (⬍0.001)
NIHSS: 0.84 (⬍0.001)
mRS indicates modified Rankin Scale; IV, intravenous.
consent, our follow-up data are likely biased toward more
severe strokes. The systematic exclusion of renal failure
likely reduced mortality in the study. Because of substantial
baseline differences between patients who received
thrombolytic therapy and those who did not, like time to
presentation, age, and baseline NIHSS, analysis dichotomized
by intravenous tPA treatment must be considered with caution. Overall, we feel that this patient sample is reasonably
representative of patients with stroke in general who present
to urban medical centers.
Our data support the use of multimodality imaging of
patients with acute stroke and those with TIA because of the
added prognostic significance obtained with the data and the
high prevalence of LVO in acute stroke and TIA. Additionally, such protocols likely expedite triage to endovascular
therapy and expedite the clinical investigation of the stroke
mechanism. Knowledge of the intracranial vascular status
provides additional, useful information to the treating physician at the time of patient presentation that may improve
decision-making.
3840
Stroke
December 2009
Source of Funding
This research was funded by a grant from the Department of Health
and Human Services, Agency for Healthcare Research and Quality,
grant number RO1- HS011392-01A1.
7.
Disclosures
W.S.S. has significant ownership interests and has served as a
consultant to Concentric Medical, Inc (significant). K.L.F. is employed with Massachusetts General Hospital, has received financial
support from Deane Institute (both significant), and has served as a
consultant to Novartis, Biosante, and GE Healthcare (Modest).
W.J.K. has an ownership interest in Neurologica (Modest). There are
no other conflicts to report.
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Stroke. 2009;40:3834-3840; originally published online October 15, 2009;
doi: 10.1161/STROKEAHA.109.561787
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