Acute Stroke Management During the COVID-19 Pandemic

During the coronavirus disease 2019 (COVID-19) pandemic, the World Health Organization recommended measures to mitigate the outbreak such as social distancing and confinement. Since these measures have been put in place, anecdotal reports describe a decrease in the number of endovascular therapy (EVT) treatments for acute ischemic stroke due to large vessel occlusion. The purpose of our study was to determine the effect on EVT for patients with acute ischemic stroke during the COVID-19 confinement. In this retrospective, observational study, data were collected from November 1, 2019, to April 15, 2020, at 17 stroke centers in countries where confinement measures have been in place since March 2020 for the COVID-19 pandemic (Switzerland, Italy, France, Spain, Portugal, Germany, Canada, and United States). This study included 1600 patients treated by EVT for acute ischemic stroke. Date of EVT and symptom onset-to-groin puncture time were collected. Mean number of EVTs performed per hospital per 2-week interval and mean stroke onset-to-groin puncture time were calculated before confinement measures and after confinement measures. Distributions (non-normal) between the 2 groups (before COVID-19 confinement versus after COVID-19 confinement) were compared using 2-sample Wilcoxon rank-sum test. The results show a significant decrease in mean number of EVTs performed per hospital per 2-week interval between before COVID-19 confinement (9.0 [95% CI, 7.8–10.1]) and after COVID-19 confinement (6.1 [95% CI, 4.5–7.7]), ( P <0.001). In addition, there is a significant increase in mean stroke onset-to-groin puncture time ( P <0.001), between before COVID-19 confinement (300.3 minutes [95% CI, 285.3–315.4]) and after COVID-19 confinement (354.5 minutes [95% CI, 316.2–392.7]). Our preliminary analysis indicates a 32% reduction in EVT procedures and an estimated 54-minute increase in symptom onset-to-groin puncture time after confinement measures for COVID-19 pandemic were put into place.

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Management of acute ischemic stroke in patients with COVID-19 infection: Report of an international panel

International Journal of Stroke ◽

10.1177/1747493020923234 ◽

2020 ◽

Vol 15 (5) ◽

pp. 540-554 ◽

Cited By ~ 39

Author(s):

Adnan I Qureshi ◽

Foad Abd-Allah ◽

Fahmi Al-Senani ◽

Emrah Aytac ◽

Afshin Borhani-Haghighi ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Current Knowledge ◽

Intravenous Thrombolysis ◽

Adult Patients ◽

World Health ◽

Stroke Patients ◽

International Panel ◽

Health Organization ◽

Tract Infections

Background and purpose On 11 March 2020, World Health Organization (WHO) declared the COVID-19 infection a pandemic. The risk of ischemic stroke may be higher in patients with COVID-19 infection similar to those with other respiratory tract infections. We present a comprehensive set of practice implications in a single document for clinicians caring for adult patients with acute ischemic stroke with confirmed or suspected COVID-19 infection. Methods The practice implications were prepared after review of data to reach the consensus among stroke experts from 18 countries. The writers used systematic literature reviews, reference to previously published stroke guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate practice implications. All members of the writing group had opportunities to comment in writing on the practice implications and approved the final version of this document. Results This document with consensus is divided into 18 sections. A total of 41 conclusions and practice implications have been developed. The document includes practice implications for evaluation of stroke patients with caution for stroke team members to avoid COVID-19 exposure, during clinical evaluation and performance of imaging and laboratory procedures with special considerations of intravenous thrombolysis and mechanical thrombectomy in stroke patients with suspected or confirmed COVID-19 infection. Conclusions These practice implications with consensus based on the currently available evidence aim to guide clinicians caring for adult patients with acute ischemic stroke who are suspected of, or confirmed, with COVID-19 infection. Under certain circumstances, however, only limited evidence is available to support these practice implications, suggesting an urgent need for establishing procedures for the management of stroke patients with suspected or confirmed COVID-19 infection.

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Outcome of endovascular treatment within and beyond 6 h without perfusion software

Scientific Reports ◽

10.1038/s41598-021-84857-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhen Jing ◽

Hao Li ◽

Shengming Huang ◽

Min Guan ◽

Yongxin Li ◽

...

Keyword(s):

Ischemic Stroke ◽

Endovascular Treatment ◽

General Anesthesia ◽

Acute Ischemic Stroke ◽

Clinical Outcomes ◽

Symptom Onset ◽

Anterior Circulation ◽

Vessel Occlusion ◽

Group A ◽

Group B

AbstractEndovascular treatment (EVT) has been accepted as the standard of care for patients with acute ischemic stroke. The aim of the present study was to compare clinical outcomes of patients who received EVT within and beyond 6 h from symptom onset to groin puncture without perfusion software in Guangdong district, China. Between March 2017 and May 2018, acute ischemic stroke patients who received EVT from 6 comprehensive stroke centers, were enrolled into the registry study. In this subgroup study, we included all patients who had acute proximal large vessel occlusion in the anterior circulation. The demographic, clinical and neuroimaging data were collected from each center. A total of 192 patients were included in this subgroup study. They were divided into two groups: group A (n = 125), within 6 h; group B (n = 67), 6–24 h from symptom onset to groin puncture. There were no substantial differences between these two groups in terms of 90 days favorable outcome (modified Rankin scale [mRS] ≤ 2, P = 0.051) and mortality (P = 0.083), and the risk of symptomatic intracranial hemorrhage at 24 h (P = 0.425). The NIHSS (median 16, IQR12-20, group A; median 12, IQR8-18, group B; P = 0.009) and ASPECTS (median 10, IQR8-10, group A; median 9, IQR8-10, group B; P = 0.034) at baseline were higher in group A. The anesthesia method (general anesthesia, 21.3%, group A vs. 1.5% group B, P = 0.001) were also statistically different between the two groups. The NIHSS and ASPECTS were higher, and general anesthesia was also more widely used in group A. Clinical outcomes were not significantly different within 6 h versus 6–24 h from symptom onset to groin puncture in this real world study.

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Integrated Stroke System Model Expands Availability of Endovascular Therapy While Maintaining Quality Outcomes

Stroke ◽

10.1161/strokeaha.120.032710 ◽

2021 ◽

Author(s):

Victor Lopez-Rivera ◽

Sergio Salazar-Marioni ◽

Rania Abdelkhaleq ◽

Sean I. Savitz ◽

Alexandra L. Czap ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Prehospital Care ◽

Stroke Onset ◽

Large Vessel ◽

Advisory Council ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Interhospital Transfer ◽

Lower Volume

Background and Purpose: The optimal endovascular stroke therapy (EVT) care delivery structure is unknown. Here, we present our experience in creating an integrated stroke system (ISS) to expand EVT availability throughout our region while maintaining hospital and physician quality standards. Methods: We identified all consecutive patients with large vessel occlusion acute ischemic stroke treated with EVT from January 2014 to February 2019 in our health care system. In October 2017, we implemented the ISS, in which 3 additional hospitals (4 total) became EVT-performing hospitals (EPHs) and physicians were rotated between all centers. The cohort was divided by time into pre-ISS and post-ISS, and the primary outcome was time from stroke onset to EPH arrival. Secondary outcomes included hospital and procedural quality metrics. We performed an external validation using data from the Southeast Texas Regional Advisory Council. Results: Among 513 patients with large vessel occlusion acute ischemic stroke treated with EVT, 58% were treated pre-ISS and 43% post-ISS. Over the study period, EVT procedural volume increased overall but remained relatively low at the 3 new EPHs (<70 EVT/y). After ISS, the proportion of patients who underwent interhospital transfer decreased (46% versus 37%; P <0.05). In adjusted quantile regression, ISS implementation resulted in a reduction of time from stroke onset to EPH arrival by 40 minutes ( P <0.01) and onset to groin puncture by 29 minutes ( P <0.05). Rates of postprocedural hemorrhage, modified Thrombolysis in Cerebral Infarction (TICI) 2b/3, and 90-day modified Rankin Scale were comparable at the higher and lower volume EPHs. The improvement in onset-to-arrival time was not reflective of overall improvement in secular trends in regional prehospital care. Conclusions: In our system, increasing EVT availability decreased time from stroke onset to EPH arrival. The ISS provides a framework to maintain quality in lower volume hospitals.

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Abstract WP40: “Good” Angiographic Collateral Circulation Correlates With Lower Dwi Infarct Volumes In Acute Ischemic Stroke

Stroke ◽

10.1161/str.44.suppl_1.awp40 ◽

2013 ◽

Vol 44 (suppl_1) ◽

Author(s):

Esteban Cheng-Ching ◽

Dolora Wisco ◽

Shumei Man ◽

Ferdinand Hui ◽

Gabor Toth ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Symptom Onset ◽

Collateral Circulation ◽

Infarct Volume ◽

Artery Occlusion ◽

Grading System ◽

Large Artery ◽

Anterior Circulation ◽

Vessel Occlusion

Background and purpose Large artery occlusion leads to ischemic stroke which volume is influenced by time from symptom onset. This effect is modulated by several factors, including the presence and degree of collateral circulation. We analyze the correlation between a standard angiographic collateral grading system and DWI infarct volumes. Methods We reviewed a prospectively collected retrospective database of ischemic stroke patients admitted between august of 2006 and december of 2011. We included patients with anterior circulation acute ischemic stroke presenting within 8 hours from symptom onset with large vessel occlusion, who underwent pre-treatment MRI and endovascular therapy. DWI infarct volumes were measured by region of interest. ASITN collateral grading system was used and grouped into “good collaterals” for grades 3 and 4, and “poor collaterals” for grades 0, 1 and 2. JMP statistical software was utilized. Results 152 patients (71 (46.7%) male, mean age: 68±15 years;) were included in the initial analysis. We identified 49 patients who had angiographic collateral circulation grading. Seven patients had ASITN collateral grade 0 with mean infarct volume of 27.6 cc, 25 had collateral grade of 1 with mean infarct volume of 27.9 cc, 10 had collateral grade of 2 with mean infarct volume of 23.4 cc, 5 had collateral grade of 3 with mean infarct volume of 6.3 cc, and 2 had collateral grade of 4 with mean infarct volume of 14.6 cc. Forty two patients had “poor collaterals” with a mean infarct volume of 26.8 cc. Seven patients had “good collaterals” with mean infarct volume of 8.7 cc. When comparing the infarct volumes between these two groups, the difference was statistically significant (p=0.017). Conclusions In anterior circulation acute ischemic stroke, “good” angiographic collateral circulation defined as ASITN grading system of 3 or 4, correlates with lower infarct volumes on presentation.

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Treatment of Acute Ischemic Stroke due to Large Vessel Occlusion With COVID-19

Stroke ◽

10.1161/strokeaha.120.030574 ◽

2020 ◽

Vol 51 (8) ◽

pp. 2540-2543 ◽

Cited By ~ 33

Author(s):

Simon Escalard ◽

Benjamin Maïer ◽

Hocine Redjem ◽

François Delvoye ◽

Solène Hébert ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Mechanical Thrombectomy ◽

Intravenous Thrombolysis ◽

Stroke Onset ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Neurological Improvement ◽

Poor Outcomes

Background and Purpose: Higher rates of strokes have been observed in patients with coronavirus disease 2019 (COVID-19), but data regarding the outcomes of COVID-19 patients suffering from acute ischemic stroke due to large vessel occlusion (LVO) are lacking. We report our initial experience in the treatment of acute ischemic stroke with LVO in patients with COVID-19. Methods: All consecutive patients with COVID-19 with acute ischemic stroke due to LVO treated in our institution during the 6 first weeks of the COVID-19 outbreak were included. Baseline clinical and radiological findings, treatment, and short-term outcomes are reported. Results: We identified 10 patients with confirmed COVID-19 treated for an acute ischemic stroke due to LVO. Eight were men, with a median age of 59.5 years. Seven had none or mild symptoms of COVID-19 at stroke onset. Median time from COVID-19 symptoms to stroke onset was 6 days. All patients had brain imaging within 3 hours from symptoms onset. Five patients had multi-territory LVO. Five received intravenous alteplase. All patients had mechanical thrombectomy. Nine patients achieved successful recanalization (mTICI2B-3), none experienced early neurological improvement, 4 had early cerebral reocclusion, and a total of 6 patients (60%) died in the hospital. Conclusions: Best medical care including early intravenous thrombolysis, and successful and prompt recanalization achieved with mechanical thrombectomy, resulted in poor outcomes in patients with COVID-19. Although our results require further confirmation, a different pharmacological approach (antiplatelet or other) should be investigated to take in account inflammatory and coagulation disorders associated with COVID-19.

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369 The TREVO Registry-Subgroup Analysis, Treatment Beyond 6 Hours

Neurosurgery ◽

10.1093/neuros/nyx417.369 ◽

2017 ◽

Vol 64 (CN_suppl_1) ◽

pp. 286-286

Author(s):

Mandy Jo Binning ◽

Erol Veznedaroglu ◽

Ronald Budzik ◽

Joey English ◽

Blaise Baxter ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Real World ◽

Symptom Onset ◽

Subgroup Analysis ◽

Mechanical Thrombectomy ◽

Stent Retriever ◽

Real World Data ◽

Vessel Occlusion ◽

Significant Difference

Abstract INTRODUCTION Current randomized trials demonstrating superiority of mechanical thrombectomy for the treatment of acute ischemic stroke for anterior circulation large vessel occlusion, have enrolled patients with symptom onset up to 6 hours. Outcomes of thrombectomy beyond 6 hours have not been well studied. The Trevo Registry is designed to assess real world outcomes of the Trevo Retriever in patients experiencing acute ischemic stroke. Trevo registry has currently enrolled 1431 patients with 90-day outcome data. Outcomes of patients treated beyond 6 hours of symptom onset were studied. METHODS The study design is a prospective, open-label, consecutive enrollment, multi-center, global registry of all patients who undergo mechanical thrombectomy for acute stroke using the Trevo stent retriever as the initial device. Enrollment is expected to reach 2000 subjects at up to 100 sites. Subgroup analysis of enrolled patients treated beyond 6 hours of symptom onset and with 90-day follow-up was performed. RESULTS >As of March 24, 2017, a total of 1846 total patients were enrolled. Median NIHSS at admission was 15.5 (IQR 11–20). The majority of patients (67.4%) were treated at 6 hours or less from last known normal with a median procedure time of 50 minutes (8-286 minutes). In patients treated after 6 hours from time last known well, the revascularization rate was 93.7% with symptomatic ICH of 1.8% and 90-day mRS = 2 was 51.8%. Subgroup analysis of patients presenting within 6 hours and those presenting beyond 6 hours showed no significant difference in patient demographics or medical comorbidities. There was no difference in complication rate or 90-day outcome between the two groups. CONCLUSION The Trevo Retriever Registry represents the first look at real world data with stent retriever use in the era of clinical trials showing the overwhelming benefit of stent retrievers to treat acute ischemic stroke. This data represents real world use of the Trevo Retriever including those treated beyond 6 hours after stroke symptoms (33.8%), and this data adds to the results from recent trials with restricted eligibility criteria.

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Efficacy and Safety of a Novel Thrombectomy Device in Patients With Acute Ischemic Stroke: A Randomized Controlled Trial

Frontiers in Neurology ◽

10.3389/fneur.2021.686253 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yongxin Zhang ◽

Weilong Hua ◽

Zifu Li ◽

Ya Peng ◽

Zhian Han ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Symptom Onset ◽

Test Group ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Randomized Controlled ◽

All Cause Mortality ◽

Solitaire Fr

Purpose: The Tonbridge stent is a novel retriever with several design improvements which aim to achieve promising flow reperfusion in the treatment of acute ischemic stroke (AIS). We conducted a randomized controlled, multicenter, non-inferiority trial to compare the safety and efficacy of the Tonbridge stent with the Solitaire FR.Methods: AIS patients aged 18–85 years with large vessel occlusion in anterior circulation who could undergo puncture within 6 h of symptom onset were included. Randomization was performed on a 1:1 ratio to thrombectomy with either the Tonbridge stent or the Solitaire FR. The primary efficacy endpoint was successful reperfusion using a modified thrombolysis in cerebral infarction score (mTICI) of 2b/3. Safety outcomes were symptomatic intracranial hemorrhage (sICH) within 24 ± 6 h and all-cause mortality within 90 days. A clinically relevant non-inferiority margin of 12% was chosen as the acceptable difference between groups. Secondary endpoints included time from groin puncture to reperfusion, National Institutes of Health Stroke Scale (NIHSS) score at 24 h and at 7 days, and a modified Rankin Scale (mRS) score of 0–2 at 90 days.Results: A total of 220 patients were enrolled; 104 patients underwent thrombectomy with the Tonbridge stent and 104 were treated with the Solitaire FR. In all test group patients, the Tonbridge was used as a single retriever without rescuing by other thrombectomy devices. Angioplasty with balloon and/or stent was performed in 26 patients in the Tonbridge group and 16 patients in the Solitaire group (p = 0.084). Before angioplasty, 86.5% of those in the Tonbridge group and 81.7% of those in the Solitaire group reached successful reperfusion (p = 0.343). Finally, more patients in the Tonbridge group achieved successful reperfusion (92.3 vs. 84.6%, 95% CI of difference value 0.9–16.7%, p < 0.0001). There were no significant differences on sICH within 24 ± 6 h between the two groups. All-cause mortality within 90 days was 13.5% in the Tonbridge group and 16.3% in the Solitaire group (p = 0.559). We noted no significant differences between groups on the NIHSS at either 24 h or 7 days and the mRS of 0–2 at 90 days.Conclusion: The trial indicated that the Tonbridge stent was non-inferior to the Solitaire FR within 6 h of symptom onset in cases of large vessel occlusion stroke.Clinical Trial Registration:ClinicalTrials.gov, number: NCT03210623.

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Impact of the COVID-19 Pandemic on Acute Ischemic Stroke Presentation, Treatment, and Outcomes

Stroke Research and Treatment ◽

10.1155/2021/8653396 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Timothy G. White ◽

Gabriela Martinez ◽

Jason Wang ◽

Michele Gribko ◽

Artem Boltyenkov ◽

...

Keyword(s):

Ischemic Stroke ◽

Stroke Volume ◽

Acute Ischemic Stroke ◽

World Health ◽

Global Pandemic ◽

Significant Difference ◽

Time Periods ◽

Health Organization ◽

Get With The Guidelines ◽

The Impact

Introduction. The World Health Organization declared COVID-19 a global pandemic last year. While a clear impact of COVID-19 on the declining stroke volume has been reported, its overall impact on stroke presentation and clinical outcomes has not been established. The purpose of this study was to assess the impact of COVID-19 on acute ischemic stroke volume, presentation, treatment, and outcomes at comprehensive stroke centers. Methods. A retrospective review of patients with a discharge diagnosis of acute ischemic stroke from the Get With The Guidelines database was performed from January 1, 2019, to July 1, 2020. The following time periods were defined: Pre-COVID (January/February), Peak-COVID (March/April), and Post-COVID (May/June). Bivariate analyses were performed comparing the 2020 and 2019 time periods to determine differences in stroke volume, presentation, treatment, and outcomes. Results. Stroke volumes were significantly lower during the Peak-COVID period in 2020 compared to that in 2019, with an absolute decline of 49.5% ( P < 0.001 ). Patients were more likely to present after 24 hours from last known well during the 2020 Peak-COVID period ( P = 0.03 ). However, there was not a significant difference in the rate of treatment with either the tissue plasminogen activator (tPA) or mechanical thrombectomy during the Peak-COVID period. Interestingly, relative treatment rates increased during the 2020 Post-COVID period to 11.4% ( P = 0.01 ). Conclusions. The overall ischemic stroke volume decreased during the pandemic, and patients had a tendency to present later, beyond eligible treatment windows. However, rates of treatment, patient demographics, and stroke outcomes did not significantly change when compared to the prior year.

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Plasma Neurofilament Light Chain Predicts Large Vessel Occlusions in Patients with Acute Ischemic Stroke

10.21203/rs.3.rs-148625/v1 ◽

2021 ◽

Author(s):

zhiqiang wang ◽

Rongyu Wang ◽

Yuxia Li ◽

Mao Li ◽

Yaodan Zhang ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Single Molecule ◽

Light Chain ◽

Symptom Onset ◽

Large Vessel ◽

Western China ◽

Stroke Severity ◽

Vessel Occlusion ◽

Neurofilament Light Chain

Abstract BackgroundPlasma neurofilaments light chain (pNfL) is a marker of axonal injury. The aim of this study was to evaluate the role of pNfL as a predictive biomarker for stroke due to large vessel occlusion (LVO).MethodsThis retrospective study was developed from a prospectively collected stroke database, which was conducted at a large academic comprehensive stroke center in western China. Consecutive patients ≥18 years with first-ever acute ischemic stroke (AIS) of anterior circulation within 24 hours of symptom onset were included. Stroke severity was analyzed at admission using the NIHSS score. The pNfL drawn within 24 h from symptom onset was analyzed with a novel ultrasensitive single molecule array. The diagnosis of LVO was based on vascular imaging.ResultsA total of 845 patients (male, 480 (56.80%); mean age, 62.67 (±11.84) years) were included analysis, and 144 (17.00%) were diagnosed with LVO. pNfL was markedly higher in patients with LVO (56.99(±14.67) versus 37.86(±13.82) pg/ml; P<0.001) than Non-LVO. pNfL was valuable for the prediction of LVO (OR, 1.099; 95% CI, 1.081-1.118; P<0.001), even adjusted for conventional risk factors (OR, 1.078; 95% CI, 1.058-1.098; P<0.001). The best cut-off value of pNfL to differentiate between patients with LVO and Non-LVO was 43.08 pg/mL, which yielded a sensitivity of 84.70% and specificity of 66.00%, with the area under the curve (AUC) at 0.826 (95% CI, 0.792-0.860; P<0.001). The highest AUC was reached by a combination of pNfL and NIHSS (AUC, 0.876; 95% CI, 0.849-0.902; P<0.001).ConclusionsStrokes with LVO were distinguishable from those without LVO following the determination of pNfL in the blood samples within 24 hours of onset. The pNfL is a promising biomarker of AIS with LVO.Clinical trial registration: ChiCTR1800020330.

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CT Hypoperfusion–Hypodensity Mismatch to Identify Patients With Acute Ischemic Stroke Within 4.5 Hours of Symptom Onset

Neurology ◽

10.1212/wnl.0000000000012891 ◽

2021 ◽

pp. 10.1212/WNL.0000000000012891

Author(s):

Peter B Sporns ◽

André Kemmling ◽

Heike Minnerup ◽

Lennart Meyer ◽

Christos Krogias ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Symptom Onset ◽

Predictive Value ◽

Interobserver Agreement ◽

Time Window ◽

Stroke Onset ◽

Class Iii ◽

Predictive Values

ObjectiveTo test the hypothesis that CT hypoperfusion-hypodensity mismatch identifies patients with ischemic stroke within 4.5 hours of symptom onset.MethodsWe therefore performed the “retrospective multicenter hypoperfusion-hypodensity mismatch for the identification of patients with stroke within 4.5 hours study” of patients with acute ischemic stroke and known time of symptom onset. The predictive values of hypoperfusion-hypodensity mismatch for the identification of patients with symptom onset within 4.5 hours were the main outcome measure.ResultsOf 666 patients, 548 (82.3 %) had multimodal CT within 4.5 hours and 118 (17.7%) beyond. Hypoperfusion-hypodensity mismatch was visible in 516 (94.2%) patients with symptom onset within and in 30 (25.4%) patients beyond 4.5 hours. CT hypoperfusion-hypodensity mismatch identified patients within 4.5 hours of stroke onset with 94.2% (95% CI: 91.9-95.8%) sensitivity, 74.6% (95% CI: 66.0-81.6%) specificity, 94.5% (95% CI: 92.3-96.1%) positive predictive value, and 73.3% (95% CI: 64.8-80.4%) negative predictive value. Interobserver agreement for hypoperfusion-hypodensity mismatch was substantial (κ=0.61, 95% CI 0.53-0.69).ConclusionsIn conclusion, patients with acute ischemic stroke with absence of a hypodensity on native CT within the hypoperfused core lesion on perfusion CT (hypoperfusion-hypodensity mismatch) are likely to be within the time window of thrombolysis. Applying this method may guide the decision to use thrombolysis in patients with unknown time of stroke onset.Classification of EvidenceThis study provides Class III evidence that CT hypoperfusion-hypodensity mismatch identifies patients with stroke within 4.5 hours of onset.

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