Intracranial Large Vessel Occlusion as a Predictor of Decline
in Functional Status After Transient Ischemic Attack
Sharon N. Poisson, MD; Mai N. Nguyen-Huynh, MD, MAS; S. Claiborne Johnston, MD, PhD;
Karen L. Furie, MD; Michael H. Lev, MD; Wade S. Smith, MD, PhD
Background and Purpose—Clinical scores help predict outcome after transient ischemic attack (TIA), and imaging studies
may improve the accuracy of predictions. Intracranial large vessel occlusion (LVO) predicts poor outcome after stroke,
but the natural history of symptomatic intracranial LVO in patients with TIA is unknown.
Methods—We studied patients presenting with TIA in the STOP Stroke Study, a prospective imaging-based study of stroke
outcomes. All patients underwent brain CTA. If an intracranial vascular occlusion was found in an appropriate territory
to account for clinical findings, then it was judged to be a symptomatic LVO. Baseline characteristics, follow-up events,
and outcomes were collected. Characteristics of patients with and without LVO were compared using ?2and t tests.
Predictors of LVO were analyzed by univariate and multivariate analysis. LVO was assessed as a predictor of
asymptomatic outcome (modified Rankin scale [mRS] score, 0), poor outcome (mRS score ?3), and increase in mRS
score over the study period.
Results—Of 97 patients with TIA, 13 (13%) had symptomatic intracranial LVO. Patients with LVO had higher baseline
NIHSS on emergency department arrival, which was an independent predictor of LVO (OR, 1.15 per point; 95% CI,
1.02–1.29; P?0.02). Patients with LVO were more likely to have an increase in mRS score during the 90-day follow-up
(P?0.03). LVO independently predicted an increase in mRS score (OR, 4.76; 95% CI, 1.23–18.43; P?0.02) and was
a borderline predictor of poor outcome (mRS score ?3; OR, 5.07; 95% CI, 0.92–28.03; P?0.06).
Conclusions—LVO is found in ?1 in 10 patients presenting with TIA and predicts a decline in functional status, likely
attributable to new brain ischemia. (Stroke. 2011;42:44-47.)
Key Words: intracranial arterial diseases ? prognosis ? transient ischemic attack
after their initial event, with frequencies of 10% to 20%
within the first 3 months.1–3Clinical scores predict outcome
after TIA with some success,4,5and imaging studies have
shown promise in improving the accuracy of predictions.6–10
Intracranial large vessel occlusions account for a large num-
ber of acute ischemic strokes and predict poor outcome after
stroke and in combined groups of TIA and minor stroke.7,11The
natural history of symptomatic large vessel occlusion that does
not result in stroke, however, has not been well-described.
In this study, we evaluated the frequency of intracranial
large vessel occlusion on CT angiogram among patients
presenting with TIA to large academic medical centers and its
relationship to neurological and functional outcomes. We
hypothesized that intracranial large vessel occlusions causing
TIA would be predictors of poor outcome.
atients with transient ischemic attack (TIA) are known to
be at high risk for stroke in the days, weeks, and months
Materials and Methods
The Screening Technology and Outcomes Project in Stroke (STOP
Stroke) Study is a prospective, imaging-based study of stroke
outcomes completed at 2 urban, academic medical centers. Consec-
utive patients with suspected acute stroke or TIA who presented
within 24 hours of symptom onset to the institutions’ emergency
departments and who underwent multi-modality CT/CTA were
approached for consent for 6-month follow-up and collection of
clinical data. Both institutions routinely used this 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. Patients were excluded if iodinated contrast agent
administration was contraindicated (ie, history of allergy, pregnancy,
congestive heart failure, increased creatinine) or if there was non-
contrast CT evidence of intracranial hemorrhage. 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 for 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. TIA was defined as a sudden, focal neurological
deficit lasting ?24 hours, presumed to be of vascular origin, and
confined to an area of the brain or eye perfused by a specific artery.
Because the diagnoses were ascribed after all information had been
Received May 19, 2010; accepted July 29, 2010.
From the Department of Neurology (S.N.P., M.N.N.H., S.C.J., W.S.S.), Department of Epidemiology and Biostatistics (S.C.J.), University of
California, San Francisco, Calif; Department of Neurology (K.L.F., M.H.L.), Massachusetts General Hospital, Boston, Mass.
Correspondence to Sharon N. Poisson, MD, 505 Parnassus Avenue, Box 0114, San Francisco, CA 94143-0114. E-mail Sharon.Poisson@UCSFmedctr.org
© 2010 American Heart Association, Inc.
Stroke is available at http://stroke.ahajournals.orgDOI: 10.1161/STROKEAHA.110.591099
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