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J Stroke > Volume 19(3); 2017 > Article
Sinn, Kasab, Banerjee, and Ozark: Rate of Stroke Mimics over Telestroke
Dear Sir:
Intravenous thrombolysis (IVT) remains the cornerstone of acute ischemic stroke treatment [1]. However, use of IVT has remained low due to lacking access to emergency medicine care [2]. Successful implementation of a statewide telestroke network at the Medical University of South Carolina has increased post-IVT transfer (drip-and-ship) from 28 cases in 2008 to 336 in 2015 [3]. A major limitation that consulting neurologists may have during telestroke care is inability to perform first-hand examination before making critical decisions. We investigated whether telestroke is associated with increased frequency of stroke mimics (SM).
A retrospective study was conducted to compare patients who received IVT through telestroke between January 2013 and October 2014 (telestroke group) to those who had IVT directly during the same period (in-house group). Acute ischemic stroke was defined based on either radiological evidence or clinical evidence of symptoms persisting ≥24 hours or until death, and other etiologies excluded. SM was defined as a nonischemic condition mimicking focal ischemic strokes without radiological evidence of acute localized cerebral ischemia relevant to presenting symptoms. To identify SM, we screened cases without acute stroke on 24 hour post-IVT images first. SM cases were identified based on primary discharge diagnoses. Then, a panel with two vascular and two board-certified neurologists reviewed the residual cases to determine them as SM or as neuroimaging-negative cerebral ischemia.
During the study period, 196 patients in the telestroke group and 90 patients in the in-house group received IVT. One case in each group was excluded due to insufficient medical records. Baseline clinical characteristics in each group are shown in Table 1. In the telestroke group, neurological deficit was more severe (median NIHSS, interquartile range: 11, 6–17 vs. 8, 4–13, P=0.005). The rate of post thrombolysis intracerebral hemorrhage was 24 (12.3%) vs. 10 (11.4%) (P=0.977) in the telestroke and in-house groups respectively (Table 1). There was no difference in the percentage of patients achieving good functional outcome (49% in the telestroke vs. 43% in the in-house group).
There were 53 cases (27.2%) and 13 cases (14.8%) of SM in the telestroke and in-house groups respectively (P=0.033) (Table 2). Seventy-eight (40.0%) out of 195 cases in the telestroke group and 30 (34.1%) out of 88 in the in-house did not have radiological evidence of acute stroke on 24 hours post-tPA scans (P=0.415). Logistic regression analysis revealed previous history of seizures, psychiatric conditions and migraine as risk factors of SM (data not shown). SM in both groups combined was associated lower risk of intracranial bleeding (3.0% vs. 18.4%, P<0.0005) and better functional outcomes at discharge (modified Rankin Scale of 0 and 1: 69.7% vs. 40.1%, P<0.0005).
Our study found that telestroke under drip-and-ship paradigm is associated with an increased frequency of SM among patients who undergo IVT, as compared to patients who received IVT after an in-person evaluation.
Telestroke neurologists can encounter the dilemma of “swift or sure” [4] where one may lose chance of good outcome by delaying thrombolysis to gather additional information for diagnostic accuracy. Since it is well known that IVT is relatively safe and functional outcomes are favorable in SM [5], some neurologists may tend to treat a patient with IVT with an unclear clinical scenario. Our telestroke network serves the state of South Carolina, a part of the “stroke belt” of the USA with the highest stroke incidence, and morbidity. This fact may contribute to lower threshold of giving IVT when a diagnosis of acute stroke is unclear but still possible.
The increased frequency of SM could be from the method for case identification. We used a multiple step process to identify SM whereas most studies used one of three methods or in combination including radiological evidence, alternative discharge diagnoses and retrospective review [6]. This difference might have contributed to the higher frequencies of SM in both groups of our study.
Our study also revealed safety and favorable outcome of IVT in SM at the time of discharge. Our study has some limitations, mainly resulting from its retrospective nature. In addition, our study is a single-center study and its result might not be generalizable.

Conflicts of Interest

The authors have no financial conflicts of interest.

Table 1.
Characteristics and functional outcomes of the telestroke and the in-house groups
Telestroke group In-house group P
Number of cases 195 88
Age 64.0±14.1 64.3±15.5 0.875
Female 104 (53.3) 49 (55.7) 0.812
Race 0.041*
 White 68 55
 Non-white 32 45
Past medical history
 Atrial fibrillation 31 (15.9) 20 (22.7) 0.224
 Diabetes mellitus 61 (31.3) 27 (30.7) 1.000
 Hypertension 148 (75.9) 72 (81.8) 0.340
 Coronary artery disease 60 (30.8) 19 (21.6) 0.147
 Peripheral artery disease 6 (3.1) 4 (4.5) 0.786
 Congestive heart failure 20 (10.3) 15 (17.0) 0.158
 Stroke/transient ischemic attack 60 (30.8) 23 (26.1) 0.515
 Smoking (for the past 5 years) 70 (35.9) 23 (26.1) 0.197
 Seizure/epilepsy 14 (7.2) 2 (2.3) 0.169
 Migraine 11 (5.6) 7 (8.0) 0.635
 Cognitive problems/dementia 15 (7.7) 5 (5.7) 0.719
 Psychiatric diseases 34 (17.4) 16 (18.2) 1.000
Blood pressure (mmHg)
 Systolic blood pressure 151.5±24.3 149.3±28.7 0.489
 Diastolic blood pressure 83.8±15.4 78.4±18.9 0.014*
NIHSS on presentation 11 (6–17) 8 (4–13) 0.005*
Acute neurovascular intervention 23 (11.8) 17 (19.3) 0.134
Image modality of 24 hours post-tPA scan 0.108
 MRI:CT (%) 61:39 50:50
Intracranial bleeding on post-tPA scan 24 (12.3) 10 (11.4) 0.977
Modified Rankin Scale (%)
 0–1 49 43
 2–4 38 47
 5–6 13 10
Disposition
 Home 127 (65.1) 55 (62.5)
 Rehabilitation facility 43 (22.1) 24 (27.3)
 Deceased/hospice 24 (12.3) 8 (9.1)
 Others 1 (0.5) 1 (1.1)
Values are presented as mean±standard deviation, number (%) or median (interquartile range) unless otherwise indicated. Analyzed with Student t-test or Mann-Whitney U-test for continuous variables or with Fisher’s exact test for categorical variables. Intracranial bleeding defined any new bleeding seen on post-IVT brain images regardless of clinical symptoms.
NIHSS, National Institute of Health Stroke Scale; tPA, tissue plasminogen activator; MRI, magnetic resonance imaging; CT, computed tomography.
* P<0.05.
Table 2.
Risk of stroke mimics, NNCI and acute ischemic stroke
SM* Ischemic events
NNCI Acute ischemic stroke NNCI+acute ischemic stroke
Telestroke group (n=195) 53 (27.2) 25 (12.8) 117 (60.0) 142 (72.8)
In-house group (n=88) 13 (14.8) 17 (19.3) 58 (65.9) 75 (85.2)
Values are presented as number (%).
NNCI, neuro-image negative cerebral ischemia; SM, stroke mimics.
* Twenty seven SM cases identified based on discharge summary. The panel reviewed 80 cases. Twenty cases needed a third reviewed because initial two reviewers disagreed. Thirty nine SM cases decided by the panel;
One case has acute stroke on image on post-intravenous thrombolysis day 3;
Fisher’s exact test for independence indicated increased association between stroke mimics with telestroke, P=0.033.

References

1. National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med 1995;333:1581–1587.
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2. Katzan IL, Furlan AJ, LIoyd LE, Frank JI, Harper DL, Hinchey JA, et al. Use of tissue-type plasminogen activator for acute ischemic stroke: the Cleveland area experience. JAMA 2000;283:1151–1158.
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3. Al Kasab S, Adams RJ, Jones DJ, Holmstedt CA. Medical University of South Carolina Telestroke: a telemedicine facilitated network for stroke treatment in South Carolina-a progress report Telemed J E Health; 2017. Epub ahead of print.

4. Saver JL, Barsan WG. Swift or sure?: the acceptable rate of neurovascular mimics among IV tPA-treated patients. Neurology 2010;74:1336–1337.
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5. Winkler DT, Fluri F, Fuhr P, Wetzel SG, Lyrer PA, Ruegg S, et al. Thrombolysis in stroke mimics: frequency, clinical characteristics, and outcome. Stroke 2009;40:1522–1525.
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6. Chernyshev OY, Martin-Schild S, Albright KC, Barreto A, Misra V, Acosta I, et al. Safety of tPA in stroke mimics and neuroimaging-negative cerebral ischemia. Neurology 2010;74:1340–1345.
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