Radiographic Characteristics of Mild Ischemic Stroke Patients With Visible Intracranial Occlusion: The INTERRSeCT Study
Abstract
Background and Purpose:
Early neurological deterioration occurs in one-third of mild strokes primarily due to the presence of a relevant intracranial occlusion. We studied vascular occlusive patterns, thrombus characteristics, and recanalization rates in these patients.
Methods:
Among patients enrolled in INTERRSeCT (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography), a multicenter prospective study of acute ischemic strokes with a visible intracranial occlusion, we compared characteristics of mild (National Institutes of Health Stroke Scale score, ≤5) to moderate/severe strokes.
Results:
Among 575 patients, 12.9% had a National Institutes of Health Stroke Scale score ≤5 (median age, 70.5 [63–79]; 58% male; median National Institutes of Health Stroke Scale score, 4 [2–4]). Demographics and vascular risk factors were similar between the two groups. As compared with those with a National Institutes of Health Stroke Scale score >5, mild patients had longer symptom onset to assessment times (onset to computed tomography [240 versus 167 minutes] and computed tomography angiography [246 versus 172 minutes]), more distal occlusions (M3, anterior cerebral artery and posterior cerebral artery; 22% versus 6%), higher clot burden score (median, 9 [6–9] versus 6 [4–9]), similar favorable thrombus permeability (residual flow grades I–II, 21% versus 19%), higher collateral flow (9.1 versus 7.6), and lower intravenous alteplase treatment rates (55% versus 85%). Mild patients were more likely to recanalize (revised arterial occlusion scale score 2b/3, 45%; 49% with alteplase) compared with moderate/severe strokes (26%; 29% with alteplase). In an adjusted model for sex, alteplase, residual flow, and time between the two vessel imagings, intravenous alteplase use (odds ratio, 3.80 [95% CI, 1.11–13.00]) and residual flow grade (odds ratio, 8.70 [95% CI, 1.26–60.13]) were associated with successful recanalization among mild patients.
Conclusions:
Mild strokes with visible intracranial occlusions have different vascular occlusive patterns but similar thrombus permeability compared with moderate/severe strokes. Higher thrombus permeability and alteplase use were associated with successful recanalization, although the majority do not recanalize. Randomized controlled trials are needed to assess the efficacy of new thrombolytics and endovascular therapy in this population.
Graphical Abstract
The majority of patients with ischemic stroke have either mild or transient neurological symptoms.1 Despite a seemingly benign presentation, up to one-third of these patients are dead or disabled at the 3-month follow-up.2-4 About 15% of patients with mild stroke have visible intracranial occlusions on noninvasive vascular imaging.5,6
Multiple studies have shown that the presence of a relevant intracranial large vessel occlusion is a strong predictor of early neurological and radiographic deterioration in patients with mild stroke.5,7-9 Recanalization has been associated with improved functional outcomes in mild stroke patients,10 and despite promising data from prospective studies,11,12 the safety and efficacy of recanalization therapies in this population is not well understood. Identifying mild stroke patients with intracranial occlusions who are unlikely to recanalize without reperfusion therapies is the first step to better define the ideal population for acute therapy.
The association between radiographic characteristics including thrombus location, size, and permeability, as well as leptomeningeal collateral flow and recanalization in patients with mild acute ischemic stroke and intracranial occlusion is not well defined. The INTERRSeCT study (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography) was a multicenter international prospective imaging cohort to study recanalization in patients with acute ischemic stroke and visible intracranial occlusions on computed tomography (CT) angiography (CTA).13 We sought to analyze thrombus characteristics and recanalization rates with or without intravenous alteplase in patients with mild ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score, ≤5) and compare these with patients with moderate/severe symptoms.
Methods
Data Availability Statement
Anonymized data will be shared by the corresponding author upon written request from any qualified investigator.
Study Population
Local medical ethics committees approved the study. Once a physician identified an eligible patient, written informed consent was provided by the patient or a surrogate. A total of 575 acute ischemic stroke patients with visible intracranial occlusion on baseline CTA were enrolled in the INTERRSeCT study between March 2010 through March 2016 (Figure I in the Supplemental Material). Patients were categorized into mild (NIHSS score, ≤5) and moderate/severe strokes (NIHSS score, >5). We compared clinical data, thrombus characteristics, and recanalization rates in mild versus moderate/severe strokes.
Detailed methods of the study have been reported previously.13 Briefly, patients presenting to the emergency department with symptoms consistent with ischemic stroke within 12 hours from last known well and evidence of symptomatic visible intracranial occlusions were included. Patients were excluded if they had renal impairment, age ≤40 years, contrast allergy, hypoglycemia, or if patients were unlikely to participate in follow-up. Baseline demographics, medical history, vascular risk factors, laboratory investigations, and treatment times (time from symptom onset to emergency department presentation, imaging, alteplase bolus, and the start of endovascular treatment) were recorded.
Imaging Analysis
All patients had a baseline CT scan of the head and CTA of the head and neck. CTA head was instructed to be repeated at 4±2 hours after the initial CTA unless conventional cerebral angiography was performed within that time frame for diagnostic or neurointerventional purposes. Repeat vessel imaging at 4±2 hours was selected for assessment of early recanalization with intravenous alteplase while assessing occlusions within an acute stroke workflow. All imaging analyses were completed at the imaging core laboratory blinded to all clinical information. The Alberta Stroke Program Early CT Score measured the extent of early ischemic change in the middle cerebral artery (MCA) territory on a 0-to-10 scale. Extent of intracranial thrombus was assessed using the clot burden score.14 A clot burden score of 0 implies complete occlusion of the ipsilateral anterior circulation vessels while a score of 10 implies no occlusion. The term proximal occlusion was used for occlusions in the distal internal carotid artery and proximal segment of the MCA (M1) and distal occlusion for any occlusion in the M3, anterior cerebral artery, or posterior cerebral artery, respectively. M2 MCA occlusions were classified as neither proximal nor distal as described previously.13 Permeability of intracranial thrombus to contrast (and, therefore, blood flow) was assessed using the residual flow grade.15 Residual flow grade is graded on the CTA source images (3 mm maximum intensity projections preferred) as follows—grade 0: no contrast permeation of thrombus; grade 1: contrast permeating diffusely through thrombus; grade 2: tiny hairline lumen or streak of well-defined contrast within the thrombus extending either through its entire length or part of thrombus.
Collateral blood flow was calculated using the Calgary Collateral Scoring System.16 Briefly, collaterals beyond M1 MCA occlusions were assessed. This score measured pial-arterial filling in each anterior cerebral artery–MCA and posterior cerebral artery–MCA region using two 5-point scales where vessels in the symptomatic hemisphere are compared with the asymptomatic contralateral hemisphere for number and prominence of vessels. These scores were added to obtain a maximum score of 10 points.
Recanalization of intracranial thrombus was assessed using the revised Arterial Occlusion Scale on repeat CTA head or on first angiographic acquisition of the affected intracranial circulation before endovascular therapy (EVT).17,18 The primary outcome was successful recanalization as defined as revised arterial occlusion scale score of 2b or 3 on repeat CTA or conventional cerebral angiogram obtained within 6 hours of initial CTA. The revised arterial occlusion scale score has the following categories. 0: primary occlusive thrombus remains same. 1: debulking of proximal part of the thrombus but without any recanalization. 2a: partial or complete recanalization of the primary thrombus with occlusion in major distal vascular branch. 2b: partial or complete recanalization of the primary thrombus with occlusion in minor distal vascular branch or partial recanalization of the primary thrombus with no thrombus in the vascular tree at or beyond the primary occlusive thrombus. 3: complete recanalization of the primary occlusive thrombus with no clot in the vascular tree beyond.
Statistical Analysis
For patient characteristics, continuous variables were summarized as median with interquartile range (IQR) and categorical variables were presented as frequencies with percentages. For continuous variables, differences were assessed using the Student t test if data were parametric or the Wilcoxon-Mann-Whitney test if nonparametric. For categorical variables, the Pearson χ2 test was used to compare distributions. For the mild stroke group, baseline clinical and radiographic covariates that were statistically significant in univariate analysis (P<0.10) and a priori deemed biologically relevant to the primary outcome of successful recanalization were selected: sex, use of intravenous alteplase, time between the two vessel imagings, and residual flow grade. These variables were included in the multivariable logistic regression model to assess independent factors associated with successful recanalization. When analyzing residual flow grade, logistic regression models were used to examine the associations between residual flow grade and the dichotomous outcomes, stroke severity, and occlusion sites, controlling for covariates age and sex. Most variables had a missing percentage of <5%, except for clot burden scores and collateral scores (Table I in the Supplemental Material). The complete case approach was used to include the full sample for variables with a large proportion of missingness as described previously.19 The level of statistical significance was set by a 2-sided P<0.05. All statistical analyses were performed using the SAS, version 9.3, software (SAS Institute). This study adhered to the STROBE reporting guideline (Table II in the Supplemental Material).
Results
During the study period, 575 patients with a visible intracranial occlusion in the anterior or posterior circulation were enrolled; the median age was 72 (IQR, 63–80) years; 48% were women; and the median NIHSS score was 14 (IQR, 8–19). A total of 74 (12.9%) participants had NIHSS score ≤5 (median, 4 [IQR, 2–4]). These patients had a median age of 70.5 years (IQR, 63–79), and 42% were women. Baseline clinical, imaging characteristics, and hospital treatments were compared between the mild and moderate/severe stroke categories (Table 1).
| Variable | Mild NIHSS score ≤5 (n=74) | NIHSS score >5 (n=501) | P value |
|---|---|---|---|
| Clinical | |||
| Age, y; median (IQR) | 70.5 (63–79) | 73 (63–80) | 0.36 |
| Sex: female, % | 42 | 49 | 0.23 |
| Baseline NIHSS score, median (IQR) | 4 (2–4) | 15.5 (10–20) | <0.001 |
| Medical history | |||
| Coronary artery disease, % | 23 | 21 | 0.73 |
| Stroke/transient ischemic attack, % | 11 | 17 | 0.37 |
| Hypertension, % | 62 | 62 | 0.98 |
| Diabetes, % | 15 | 14 | 0.62 |
| Dyslipidemia, % | 32 | 33 | 0.9 |
| Atrial fibrillation, % | 31 | 31 | 0.96 |
| Smoking, % | 38 | 42 | 0.65 |
| Admission blood pressure, mean | |||
| SBP (SD) | 150 (25) | 150 (26) | 0.90 |
| DBP (SD) | 82 (16) | 82 (17) | 0.71 |
| Imaging | |||
| Baseline ASPECTS, median (IQR) | 9 (8–10) | 9 (7–10) | 0.56 |
| Baseline ASPECTS within 8–10, n (%) | 85 (53) | 73 (346) | 0.029 |
| Intracranial occlusion site | |||
| Intracranial ICA and proximal M1, % | 13 | 47 | <0.001 |
| Distal M1, % | 16 | 18 | <0.001 |
| M2, % | 49 | 30 | <0.001 |
| M3, ACA and PCA, % | 22 | 6 | <0.001 |
| Right hemisphere occlusion, n (%) | 30 (22) | 46 (229) | 0.009 |
| Right hemisphere occlusions | |||
| Intracranial ICA/proximal M1, n (%) | 31 (7) | 50 (115) | <0.001 |
| Distal M1, n (%) | 14 (3) | 20 (46) | <0.001 |
| M2, n (%) | 45 (10) | 24 (56) | <0.001 |
| M3, ACA and PCA, n (%) | 9 (2) | 5 (12) | <0.001 |
| Clot burden score, median (IQR) | 9 (6–9) lower burden | 6 (4–9) higher burden | <0.001 |
| Residual flow within intracranial thrombus (%) | |||
| 0 | 78 | 81 | 0.75 |
| 1 | 9 | 10 | 0.75 |
| 2 | 12 | 9 | 0.75 |
| Total collateral score, mean (SD) | 9.1 (1.4) | 7.6 (2.2) | <0.001 |
| Total collateral score for M2, mean (SD) | 9.6 (0.9) | 8.3 (1.5) | 0.04 |
| Time from onset (last known well) to initial CT, min; mean (SD) | 240 (265) | 167 (173) | 0.02 |
| Time from onset to baseline CTA, min; mean (SD) | 246 (265) | 172 (171) | 0.02 |
| Time from baseline CT to alteplase start, min; mean (SD) | 35 (20) | 26 (16) | <0.01 |
| Second vessel imaging type: angiogram, n (%) | 8 (6) | 46 (229) | <0.01 |
| Time from baseline CTA to second vessel imaging, min; mean (SD) | 235 (78) | 166 (101) | <0.001 |
| Time from alteplase start to second vessel imaging, min; mean (SD) | 186 (82) | 147 (98) | <0.005 |
ACA indicates anterior cerebral artery; ASPECTS, Alberta Stroke Program Early CT Score; CT, computed tomography; CTA, computed tomography angiography; DBP, diastolic blood pressure; ICA, internal carotid artery; IQR, interquartile range; NIHSS, National Institutes of Health Stroke Scale; PCA, posterior cerebral artery; and SBP, systolic blood pressure.
Patients with mild strokes had similar demographics and vascular risk factor profiles as those with moderate/severe stroke. Favorable thrombus permeability (residual flow grades I and II) was similar between mild and moderate/severe groups (21% versus 19%; P=0.75). In the mild stroke group, intracranial occlusions were more likely to be in the left hemisphere (46% versus 30%; P<0.001) and more likely in M2 segments (49% versus 30%) and distal occlusions (M3, anterior cerebral artery, posterior cerebral artery) 22% versus 6% (P<0.001 overall) compared with moderate/severe strokes. There was no association between the laterality of occlusion site and mild symptoms when stratified by occlusion site except in distal occlusions: moderate/severe strokes had more right hemisphere occlusions (43% versus 13%; P<0.037; Table 1). In the analysis of the collateral scores between mild and moderate/severe strokes (excluding patients with distal occlusion), mild stroke had higher collateral scores (9.1 [n=58] versus 7.6 [n=460]; P<0.001). In a nonparametric analysis, higher collateral flow was seen in M2 MCA occlusions compared more proximal and distal occlusions in both mild (Kruskal-Wallis P=0.04) and more severe strokes (Kruskal-Wallis P<0.0001). The Figure shows examples of 2 patients with NIHSS score ≤5 with various residual flow grades and collateral scores.
Hospital presentation was delayed in mild stroke patients as compared with moderate/severe strokes; patients with mild strokes had longer symptom onset to CT head (240 versus 167 minutes; P=0.02) and onset to CTA (246 versus 172 minutes; P=0.02), respectively. A total of 82% patients received intravenous alteplase in the study. As compared with those with more severe strokes, mild stroke patients were less likely to receive intravenous alteplase (55% versus 85%; P<0.001). The times between initial CT scan and alteplase administration were significantly longer in patients with mild (35 minutes) compared with more severe strokes (26 minutes; P<0.01). The time from initial CTA to second vessel imaging was significantly longer in mild strokes compared with more severe strokes (235 versus 166 minutes; P<0.001; Table 1). The time from intravenous alteplase initiation to second imaging was longer in mild strokes compared with more severe strokes (186 versus 147 minutes; P<0.005; Table 1).
The overall rate of successful recanalization for mild and moderate/severe stroke groups was 45% and 26% with intravenous alteplase and 25% and 9% without intravenous alteplase, respectively (Table 2). Mild stroke patients recanalized at a rate of 32% in the internal carotid artery/M1, 38% in M2 MCA, and 47% in distal occlusions, whereas in moderate/severe strokes, 22% in proximal, 32% in M2 MCA, and 41% in distal occlusions (Table 2).
| NIHSS score ≤5 (n=74) | NIHSS score >5 (n=501) | |||
|---|---|---|---|---|
| Successful recanalization (rAOL 2b/3) | 33 (45%) | 129 (26%) | ||
| Alteplase status | With IV alteplase | Without IV alteplase | With IV alteplase | Without IV alteplase |
| No. of patients | 41 (55%) | 28 (37%) | 424 (85%) | 77 (15%) |
| Successful recanalization (rAOL 2b/3) | 20 (49%) | 7 (25%) | 122 (29%) | 7 (9%) |
| Successful recanalization (rAOL 2b/3) by occlusion site | ||||
| ICA/M1 (%, proportion) | 32% (7/22) | 22% (71/325) | ||
| M2 (%, proportion) | 38% (14/37) | 32% (47/148) | ||
| Distal, M3, ACA, PCA (%, proportion) | 47% (7/15) | 41% (9/22) | ||
ACA indicates anterior cerebral artery; ICA, internal carotid artery; IV, intravenous; NIHSS, National Institutes of Health Stroke Scale; PCA, posterior cerebral artery; and rAOL, revised arterial occlusion scale.
A higher residual flow grade was associated with successful recanalization in both mild (odds ratio [OR], 2.55 [95% CI, 1.21–5.35]) and more severe strokes (OR, 2.29 [95% CI, 1.71–3.08]). A logistic regression model controlling for age and sex for residual flow grade and mild stroke symptoms stratified by occlusion site showed that higher residual flow grade was associated with mild symptoms among those with M2 occlusions (OR, 2.69 [95% CI, 1.11–6.53]) but not among those with more proximal or distal occlusion sites. Similarly, when flow grade (0, 1, and 2) was used as a continuous measure for M2 occlusions, the odds of mild symptomatology increased by 87% for each point increase in the residual flow grade (OR, 1.87 [95% CI, 1.12–3.12]; P=0.02).
In multivariable analysis, intravenous alteplase use (OR, 3.80 [95% CI, 1.11–13.00]) and higher residual flow grade (OR, 8.70 [95% CI, 1.26–60.13]) were independently associated with successful recanalization in the mild stroke group (Table 3). For each minute increase in time between vessel imaging, the odds of recanalization increased by 1% ([95% CI, 1.00–1.02] P=0.05). Results were similar when clot burden score was included in the multivariable analysis. A sensitivity analysis excluding patients who underwent EVT or had more distal occlusions did not change our outcomes (Tables III and IV in the Supplemental Material).
| Mild strokes (n=74) | Recanalization, OR (95% CI) |
|---|---|
| IV alteplase use | OR, 3.80 (1.11–13.00) |
| Higher thrombus permeability (0 vs 1–2) | OR, 8.70 (1.26–60.13) |
| Latency between vessel imaging (per minute increase) | OR, 1.01 (1.001–1.02) |
| Sex | OR, 4.31 (1.27–14.69) |
IV indicates intravenous; and OR, odds ratio.
Discussion
In this multicenter study of patients with acute ischemic strokes and visible intracranial occlusions, 12.9% had mild neurological symptoms at presentation. Mild stroke had similar demographics and clinical characteristics as compared with those with moderate/severe strokes. However, they had different radiographic features with regard to occlusion site, laterality of occlusion, and collateral flow. We found significant differences in the timing of hospital presentation and practice patterns with regard to utilization of reperfusion therapies between mild and moderate/severe stroke patients. The absolute rate of successful recanalization was higher in the mild group; however, repeat imaging latency was also longer in this group. Intravenous alteplase use and higher thrombus permeability were independently associated with successful recanalization in this group. An independent association was not observed between distal occlusion and recanalization in the mild category.
Recanalization is a well-established predictor of improved clinical and radiographic outcomes in acute ischemic stroke with large vessel occlusions.20,21 Prior studies have shown that proximal occlusion and longer thrombus length were associated with lower rates of recanalization, whereas increased thrombus permeability was associated with higher rates of recanalization in all severity strokes.22-26 In our study, higher residual flow grade and increased time to repeat vessel imaging were positive predictors of successful recanalization. It is plausible that longer latencies between vessel imaging allow more time for occlusions to recanalize and for intravenous alteplase to assist in this process.
The clinical presentation and symptom severity of a particular intracranial occlusion is multifactorial, dependent on the patients’ clinical characteristics and radiographic factors along with the acuity of the occlusion. A robust collateral blood flow, primarily through leptomeningeal arteries, is among the factors as to why some occlusions in a particular location produce mild symptoms while some in similar locations create more severe symptomatology. We showed that collateral blood flow was qualitatively higher in patients with mild compared with patients with more severe neurological symptoms. This is consistent with numerous reports that show strong associations between better collateral flow and improved clinical/radiological outcomes in ischemic strokes with or without reperfusion therapies.27,28, 29 Therefore, assessment of collateral blood flow may improve stroke risk stratification and decision-making for more aggressive therapies in patients with mild neurological symptoms.
In our study, there was an association between stroke severity and laterality with higher right hemispheric stroke rates among more severe patients compared with mild patients. It is unclear how right hemispheric neurological deficits and language dominance affect the NIHSS construct and stroke severity.30 In contrast to our findings, previous studies have shown that right hemispheric strokes have milder symptoms and are more likely to have delayed presentation and symptom recognition as compared with the left hemispheric strokes.31,32 The relationship of occlusion laterality and mild strokes remains unclear and likely influenced by thrombus permeability and collateral flow.
In clinical practice, the approach to mild ischemic stroke differs from more severe strokes, particularly in the urgency of hospital presentation, neurological assessment, vascular imaging, thrombolysis utilization, and EVT.33 Our data are consistent with these findings; mild patients required an average latency of over an hour more between stroke symptom onset and initial CT brain scan as compared with more severe strokes. Similarly, the mild stroke group was less likely to receive intravenous alteplase, had significant delays in treatment initiation, and less likely to undergo conventional angiography (a surrogate marker for receiving EVT) as compared with their moderate/severe counterparts. The lower utilization rates of reperfusion therapies and delays in thrombolysis administration in mild patients have been reported previously.10,34 The delays are likely multifactorial and, in part, related to clinicians’ hesitancy in offering more aggressive therapies due to the potential risk of harm in those with seemingly nondisabling symptoms. Additionally, obtaining more advanced imaging before making treatment decisions reflects the absence of clear evidence-based guidelines regarding reperfusion therapies in this population.
This study has multiple limitations. Information regarding vascular imaging, intravenous alteplase, and EVT utilization among those who were screened but not enrolled in INTERRSeCT was not collected, which can result in a selection bias. This is particularly relevant for mild strokes where the use of intravenous thrombolysis and EVT remain controversial and vary widely between different centers. This study used 2 different modalities, CTA and conventional angiography, to measure recanalization. It is possible that conventional angiography may better detect more distal occlusions not seen on initial CTA. However, undetected thrombi on CTA are more likely to be distal and less clinically irrelevant. Another confounding factor may be recanalization due to the natural course of thrombi dissolution or the thrombolytic effect of intravenous alteplase. There was an increased average latency from the initial vessel imaging to the second vessel imaging (236 versus 166 minutes) in mild compared with more severe strokes, which may increase the rate of recanalization (spontaneous or with intravenous alteplase) in this population relative to moderate/severe patients in whom the second imaging was performed earlier. These differences in latencies may have disproportionally affected our mild stroke group with a higher rate of spontaneous recanalization.35 Finally, 90-day outcomes were collected in INTERRSeCT but beyond the scope of the current study, which focuses on radiographic characteristics of intracranial thrombi in this population.
An intracranial thrombus can result in varied clinical presentations and symptom severity, depending on patients’ age, vascular risk factors, location, radiographic characteristics, and the acuity of the intracranial occlusion. These factors may underlie dissociations between radiographic recanalization and clinical outcomes that may mediate the benefit/harm of therapies and trial enrollment. These issues create management equipoise, particularly for patients who spontaneously recanalize after acute mild ischemic strokes. Reperfusion treatments in mild strokes with a visible intracranial thrombus in large or medium vessels require randomized controlled trials and analysis of thrombus characteristics to provide further biomarkers for prognosis. The results of TEMPO-2 (A Randomized Controlled Trial of TNK-tPA Versus Standard of Care for Minor Ischemic Stroke With Proven Occlusion)—a randomized control trial for intravenous tenecteplase versus conservative management in mild strokes with vessel occlusions—will shed more light on the efficacy of new thrombolytics in this population.36
In summary, we found that over 10% of patients with symptomatic acute intracranial occlusions present with mild neurological symptoms. Radiographic characteristics such as collateral flow and thrombus permeability are associated with symptom severity and successful recanalization. Less than half of mild stroke patients with visible intracranial occlusions recanalize even with intravenous alteplase, where approximately one-third of thrombi (distal internal carotid artery and proximal M1) are accessible to thrombectomy. Future studies addressing these therapeutic options are ongoing and will further clarify the safety and efficacy of various reperfusion treatments in this population.
Article Information
Supplemental Materials
Supplemental Figure I
Supplemental Tables I–V
Acknowledgments
We wish to thank all the staff and participants of the INTERRSeCT study (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography). All statistical analyses were conducted by Hannah Gardener, ScD.
Footnote
Nonstandard Abbreviations and Acronyms
- CT
- computed tomography
- CTA
- computed tomography angiography
- EVT
- endovascular therapy
- INTERRSeCT
- Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography
- IQR
- interquartile range
- MCA
- middle cerebral artery
- NIHSS
- National Institutes of Health Stroke Scale
- OR
- odds ratio
Supplemental Material
File (supplemental materials - final.pdf)
- Download
- 374.38 KB
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© 2021 American Heart Association, Inc.
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History
Received: 23 May 2020
Revision received: 5 June 2021
Accepted: 22 June 2021
Published online: 10 November 2021
Published in print: March 2022
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Disclosures
Dr Menon reported holding a patent on a system/method for assisting in decision-making and triaging for acute stroke patients. Dr Dowlatshahi reported funding by a Heart & Stroke Foundation of Canada Clinician Scientist award. Dr Demchuk reported personal fees from Medtronic, grants from Cerenovus during the conduct of the study, personal fees from Circle NVI outside the submitted work including a patent to Circle NVI issued, and board membership and stock ownership of Circle NVI. Dr Hill reported receiving payment for serving as a stroke outcome event adjudicator for a panel of clinical trials by Merck, receiving study drug as in-kind support for the TEMPO-1 trial (TNK-tPA Evaluation for Minor Ischemic Stroke With Proven Occlusion) from Hoffmann-La Roche Canada, Ltd, grants to his institution (University of Calgary) for clinical trials from Covidien (Medtronic), Boehringer Ingelheim, Stryker, and Medtronic, holding a patent on a system/method for assisting in decision-making and triaging for acute stroke patients, owning stock in Calgary Scientific, Inc (medical imaging software company), receiving grant support from Alberta Innovates Health Solutions, Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, and the National Institutes of Neurological Disorders and Stroke, grants from the Canadian Institutes for Health Research during the conduct of the study, personal fees from Sun Pharma, nonfinancial support from Hoffmann-La Roche Canada, Ltd, grants from Covidien (Medtronic), grants from Stryker, Inc, grants from Alberta Innovates, grants from NoNO, Inc, owning stock in Pure Web, Inc (medical imaging software company), director of the Canadian Federation of Neurological Sciences, a not-for-profit group, director of the Canadian Stroke Consortium, a not-for-profit group, and is a director of Circle NeuroVascular, Inc. Dr Field reported in-kind study medication from Bayer Canada and an honorarium for Servier (speakers bureau). Dr Romano reported research salary support to the Department of Neurology at the University of Miami from National Institutes of Health (NIH)/National Institute of Mental Health (NIMH) for role as principle investigator (multiple principle investigators) of the TCSD-S study (1R01MD012467), from NIH/National Institute of Neurological Disorders and Stroke (NINDS) for role as principle investigator (co-principle investigator) of the Florida Regional Coordinating Center for StrokeNet (1U24NS107267), from Genentech for role as principle investigator of the Mild and Rapidly Improving Stroke Study, personal fees from Genentech for Steering Committee role as member of the independent data monitoring committee for the TIMELESS trial, and ownership of stock in Vycor/NovaVision for role as advisor.
Sources of Funding
This prospective cohort study was funded by an operating grant from the Canadian Institutes of Health Research.
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- Anterior Circulation Thrombectomy in Patients With Low National Institutes of Health Stroke Scale Score: Analysis of the National Inpatient Sample, Stroke: Vascular and Interventional Neurology, 4, 2, (2024)./doi/10.1161/SVIN.123.001283
- Intravenous tenecteplase compared with alteplase for minor ischaemic stroke: a secondary analysis of the AcT randomised clinical trial, Stroke and Vascular Neurology, (svn-2023-002828), (2024).https://doi.org/10.1136/svn-2023-002828
- Medical Management Versus Endovascular Treatment for Large-Vessel Occlusion Anterior Circulation Stroke With Low NIHSS, Stroke, 54, 9, (2265-2275), (2023)./doi/10.1161/STROKEAHA.123.043937
- Predictive value of clot imaging in acute ischemic stroke: A systematic review of artificial intelligence and conventional studies, Neuroscience Informatics, 3, 1, (100114), (2023).https://doi.org/10.1016/j.neuri.2022.100114
- Nonstenotic Carotid Plaques and Embolic Stroke of Undetermined Source: A Multimodality Review, American Journal of Neuroradiology, 44, 2, (118-124), (2022).https://doi.org/10.3174/ajnr.A7750
- Current State and Future for Emerging Stroke Therapies: Reflections and Reactions, Stroke, 53, 6, (2082-2084), (2022)./doi/10.1161/STROKEAHA.122.039796
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