Large Vessel Occlusion in Patients With Minor Ischemic Stroke in a Population-Based Study. The Dijon Stroke Registry

Introduction:Strategy for the acute management of minor ischemic stroke (IS) with large vessel occlusion (LVO) is under debate, especially the benefits of mechanical thrombectomy. The frequency of minor IS with LVO among overall patients is not well established. This study aimed to assess the proportion of minor IS and to depict characteristics of patients according to the presence of LVO in a comprehensive population-based setting.Methods:Patients with acute IS were prospectively identified among residents of Dijon, France, using a population-based registry (2013–2017). All arterial imaging exams were reviewed to assess arterial occlusion. Minor stroke was defined as that with a National Institutes of Health Stroke Scale (NIHSS) score of <6. Proportion of patients with LVO was estimated in the minor IS population. The clinical presentation of patients was compared according to the presence of an LVO.Results:Nine hundred seventy-one patients were registered, including 582 (59.9%) patients with a minor IS. Of these patients, 23 (4.0%) had a LVO. Patients with minor IS and LVO had more severe presentation [median 3 (IQR 2–5) vs. 2 (IQR 1–3), p = 0.001] with decreased consciousness (13.0 vs. 1.6%, p<0.001) and cortical signs (56.5 vs. 30.8%, p = 0.009), especially aphasia (34.8 vs. 15.4%, p = 0.013) and altered item level of consciousness (LOC) questions (26.1 vs. 11.6%, p = 0.037). In multivariable analyses, only NIHSS score (OR = 1.45 per point; 95% CI: 1.11–1.91, p = 0.007) was associated with proximal LVO in patients with minor IS.Conclusion:Large vessel occlusion (LVO) in minor stroke is non-exceptional, and our findings highlight the need for emergency arterial imaging in any patients suspected of acute stroke, including those with minor symptoms because of the absence of obvious predictors of proximal LVO.

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Abstract TP39: Comparative Effectiveness of Endovascular Treatment for Acute Ischemic Stroke: A Population-Based Analysis

Stroke ◽

10.1161/str.51.suppl_1.tp39 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Charlotte Zerna ◽

Edwin Rogers ◽

Doreen M Rabi ◽

Andrew M Demchuk ◽

Noreen Kamal ◽

...

Keyword(s):

Ischemic Stroke ◽

Medical Treatment ◽

Endovascular Treatment ◽

Acute Ischemic Stroke ◽

Population Based ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Population Based Study ◽

Nihss Score

Background: A heterogeneous patient population receives endovascular treatment (EVT) for acute ischemic stroke due to proximal large vessel occlusion every day. We aimed to conduct a population-based study of EVT in the province of Alberta, Canada, to understand the effectiveness in a complete population and how the magnitude of effect differs from the artificial world of clinical trials. Methods and Results: Within a three year period (April 2015 - March 2018), 576 patients fit the inclusion criteria of our study and constituted the EVT group of our analysis. The medical treatment group of the ESCAPE trial had 150 patients. Thus our total sample size was 726. We captured outcomes in clinical routine using administrative data and a linked database methodology. Primary outcome of our study was home-time. Home-time refers to the number of days that the patient was back at pre-morbid living situation without increase in level of care within 90 days of index stroke event. Median age of patients was 70 years (interquartile range (IQR) 59 - 81) and 47.8% were female. Median National Institutes of Health Stroke Scale (NIHSS) score was 17 (IQR 13 - 20). EVT was associated with an increased 90-day home-time by an average of 8.5 days compared to medical treatment alone using Cragg hurdle regression (p = 0.009). Age and higher NIHSS score were associated with decreased 90-day home-time (both p = 0.001). Multivariable logistic regression showed no association between EVT and mortality at 90 days (odds ratio 0.76, 95% confidence interval 0.47 - 1.24). Conclusions: EVT for acute ischemic stroke due to proximal large vessel occlusion was effective in our province-wide population-based study and results in increased 90-day home-time by ~8.5 days. Home-time is a novel and patient-centered outcome that reflects health circumstances that are easy to understand and meaningful to patients and their caregivers.

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Abstract 3314: The Role of Bridging with Intravenous Thrombolysis in Endovascular Therapy of Acute Ischemic Stroke.

Stroke ◽

10.1161/str.43.suppl_1.a3314 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

Omar Kass-Hout ◽

Tareq Kass-Hout ◽

Maxim Mokin ◽

David Orion ◽

Shadi Jahshan ◽

...

Keyword(s):

Ischemic Stroke ◽

Endovascular Treatment ◽

Acute Ischemic Stroke ◽

Endovascular Therapy ◽

Combined Therapy ◽

Large Vessel ◽

P Value ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Nihss Score

Background: Large vessel occlusions with a high clot burden are less likely to improve with the FDA-approved IV strategy. Endovascular therapy within the first 3 h of stroke symptom onset provides an effective alternative treatment in patients with large vessel occlusion. It is not clear if combination of IV thrombolysis and endovascular approach is superior to endovascular treatment alone. Methods: We retrospectively reviewed all cases of acute ischemic stroke with large vessel occlusion treated within the first 3 h stroke onset during the 2005-2010 period. First group received endovascular therapy within the first 3 h of stroke onset. Second group consisted of patients who received IV thrombolysis within the first 3 h followed by endovascular therapy. We compared the following outcomes: revascularization rates, NIHSS score at discharge, mRS at discharge and 3months, symptomatic hemorrhage rates and mortality. Results: Among 104 patients identified, 42 received combined therapy, and 62 received endovascular therapy only. The two groups had similar demographic (age and sex distribution) and vascular risk factors distribution, as well as NIHSS score on admission (14.8±4.7 and 16.0±5.3; p=0.23). We found no difference in TIMI recanalization rates (Thrombolysis in Myocardial Infarction scale score of 2 or 3) following combined or endovascular therapy alone (83.3% and 79.0%; p=0.59). A preferred outcome, defined as a mRS of 2 or less at 90 days also did not differ between the combined therapy group and the endovascular only group (37.5% and 34.5%; p=0.76). There was no difference in mortality rate (22.5% and 31.0%; p=0.36) and the rate of symptomatic intracranial hemorrhage (9.5% and 8.1%; p=0.73). There was a significant difference in mean time from symptom onset to endovascular treatment between the combined group (227±88 min) and endovascular only group (125±40 min; p<0.0001).Patients with good TIMI recanalization rate of 2 or 3 showed a trend of having a better mRS at 90 days in both bridging (16.67% vs. 41.18%, p-value: 0.3813) and endovascular groups (25% vs. 34.78%, p-value: 0.7326).When analyzing the correlation of mRS at 90 days with the site of occlusion, patients in the bridging group showed a trend of a better outcome when the site of occlusion was ICA (33.3% vs 30%) and MCA (66.67% vs. 27.59%) and worse outcome when the site of occlusion was in the posterior circulation (26.32% vs. 50%), however, these results were not statistically significant (p-values: 0.1735& 0.5366). Conclusion: Combining IV thrombolysis and endovascular therapy achieves similar rates of clinical outcomes, revascularization rates, complications and mortality rates, when compared with endovascular treatment alone. The combined therapy, however, significantly delays initiation of endovascular treatment. A randomized prospective trial comparing both treatment strategies in acute ischemic stroke is warranted

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Abstract 3183: Prognosis of Mild Ischemic Stroke with Large Vessel Occlusion

Stroke ◽

10.1161/str.43.suppl_1.a3183 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

Esteban Cheng-Ching ◽

Russell Cerejo ◽

Ken Uchino ◽

Muhammad S Hussain ◽

Gabor Toth

Keyword(s):

Ischemic Stroke ◽

Endovascular Therapy ◽

Time Window ◽

Optimal Treatment ◽

Large Vessel ◽

Stroke Severity ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Nihss Score ◽

Mild Stroke

Background and purpose Large vessel occlusion (LVO) in acute ischemic stroke has been reported to be an independent predictor of unfavorable clinical outcome. However, the prognosis and optimal treatment of patients with only mild neurologic deficits due to LVO are not known. Methods We performed a retrospective chart review from a database of stroke patients admitted to our large academic medical center between July 1, 2010 and June 30 , 2011. Inclusion criteria were acute stroke or TIA, presentation within 9 hours from symptom onset, large vessel occlusion as a culprit of ischemic symptoms, and mild stroke severity with initial NIH Stroke Scale (NIHSS) score <8. Results We identified 59 patients with mild ischemic stroke or TIA, who were evaluated within 9 hours from onset. Of these, 13 (22%) had culprit large vessel occlusions. Five were female, 1 had diabetes, 12 had hypertension, 7 had hyperlipidemia, 2 had atrial fibrillation and 7 were smokers. The median NIHSS score was 5. The location of arterial occlusions were 5 in M1 segment of the middle cerebral artery (MCA), 6 in M2 segment of MCA, 1 each in posterior cerebral and vertebral arteries. Two patients received acute therapy, 1 with intravenous thrombolysis and 1 with endovascular therapy. Reasons for withholding thrombolytic therapy were time window in 8, mild stroke severity in 2, and atypical presentations in 2. Reasons for withholding acute endovascular therapy were mild stroke severity in 7, imaging finding in 2, technical considerations in 2, and lack of consent in 1. From hospital admission to discharge, 10 (77%) patients had symptom improvement, 2 had worsening, and one was unchanged. At 30 days, 5 (38%) had good outcome with a modified Rankin Scale (mRS) of 0-1. Three (23%) had mRS of 2, one (8%) patient had mRS of 3. Outcomes for 4 patients were unknown. Conclusions A significant proportion of patients presenting with mild ischemic symptoms has large vessel occlusion. Acute treatment in this population is frequently withheld due to mild severity or thrombolytic time window. Despite mild symptoms at presentation, some patients are left with moderate disability. Optimal treatment options for this population should be further evaluated in a larger group of patients.

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Capability of stroke scales to detect large vessel occlusion in acute ischemic stroke : A pilot study

Ideggyógyászati Szemle ◽

10.18071/isz.74.0099 ◽

2021 ◽

Vol 74 (3-4) ◽

pp. 99-103

Author(s):

Gábor Tárkányi ◽

Zsófia Nozomi Karádi ◽

Péter Csécsei ◽

Edit Bosnyák ◽

Gergely Fehér ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Area Under The Curve ◽

Arterial Occlusion ◽

Large Vessel ◽

Screening Methods ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Cross Sectional ◽

Stroke Centre

Rapid changes of stroke management in recent years facilitate the need for accurate and easy-to-use screening methods for early detection of large vessel occlusion (LVO) in acute ischemic stroke (AIS). Our aim was to evaluate the ability of various stroke scales to discriminate an LVO in AIS. We have performed a cross-sectional, observational study based on a registry of consecutive patients with first ever AIS admitted up to 4.5 hours after symptom onset to a comprehensive stroke centre. The diagnostic capability of 14 stroke scales were investigated using receiver operating characteristic (ROC) analysis. Area under the curve (AUC) values of NIHSS, modified NIHSS, shortened NIHSS-EMS, sNIHSS-8, sNIHSS-5 and Rapid Arterial Occlusion Evaluation (RACE) scales were among the highest (>0.800 respectively). A total of 6 scales had cut-off values providing at least 80% specificity and 50% sensitivity, and 5 scales had cut-off values with at least 70% specificity and 75% sensitivity. Certain stroke scales may be suitable for discriminating an LVO in AIS. The NIHSS and modified NIHSS are primarily suitable for use in hospital settings. However, sNIHSS-EMS, sNIHSS-8, sNIHSS-5, RACE and 3-Item Stroke Scale (3I-SS) are easier to perform and interpret, hence their use may be more advantageous in the prehospital setting. Prospective (prehospital) validation of these scales could be the scope of future studies.

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Acute Neurological Deterioration in Large Vessel Occlusions and Mild Symptoms Managed Medically

Stroke ◽

10.1161/strokeaha.119.027011 ◽

2020 ◽

Vol 51 (5) ◽

pp. 1428-1434 ◽

Cited By ~ 6

Author(s):

Yasir Saleem ◽

Raul G. Nogueira ◽

Gabriel M. Rodrigues ◽

Song Kim ◽

Vera Sharashidze ◽

...

Keyword(s):

Multivariable Analysis ◽

National Institutes Of Health ◽

Neurological Deterioration ◽

Large Vessel ◽

Minor Stroke ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Endovascular Thrombectomy ◽

Nihss Score ◽

Acute Neurological Deterioration

Background and Purpose— It is unclear which factors predict acute neurological deterioration in patients with large vessel occlusion and mild symptoms. We aim to evaluate the frequency, timing, and potential predictors of acute neurological deterioration ≥4 National Institutes of Health Stroke Scale (NIHSS) points in medically managed patients with large vessel occlusion and mild presentation. Methods— Single-center retrospective study of patients with consecutive minor stroke (defined as NIHSS score of ≤5 on presentation) and large vessel occlusion from January 2014 to December 2017. Primary outcome was acute neurological deterioration ≥4 NIHSS points during the hospitalization. Secondary outcomes included ΔNIHSS (defined as discharge minus admission NIHSS score). Results— Among 1133 patients with acute minor strokes, 122 (10.6%) had visible occlusions on computed tomography angiography/magnetic resonance angiography. Twenty-four (19.7%) patients had ≥4 points deterioration on NIHSS at a median of 3.6 (1–16) hours from arrival. No clinical or radiological predictors of acute neurological deterioration ≥4 NIHSS points were observed on multivariable analysis. Rescue endovascular thrombectomy was performed more often in the ones with acute neurological deterioration ≥4 NIHSS points compared with patients with no deterioration (54% versus 0%; P <0.001). Acute neurological deterioration ≥4 NIHSS points was associated with ΔNIHSS ≥4 points (33% versus 4.9%; P <0.01) and a trend toward lower independence rates at discharge (50% versus 70%; P =0.06) compared with the group with no deterioration. In patients with any degree of neurological worsening, patients who underwent rescue thrombectomy were more likely to be independent at discharge (73% versus 38%; P =0.02) and to have a favorable ΔNIHSS (−2 [−3 to 0] versus 0 [−1 to 6]; P =0.05) compared with the ones not offered rescue thrombectomy. Conclusions— Acute neurological deterioration ≥4 NIHSS points was observed in a fifth of patients with large vessel occlusion and mild symptoms, occurred very early in the hospital course, impacted functional outcomes, and could not be predicted by any of the studied clinical and radiological variables. Rescue thrombectomy was associated with improved clinical outcomes at discharge in patients with neurological deterioration.

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Predictor of 90-day functional outcome after mechanical thrombectomy for large vessel occlusion stroke: NIHSS score of 10 or less at 24 hours

Journal of Neurosurgery ◽

10.3171/2019.10.jns191991 ◽

2019 ◽

pp. 1-7

Author(s):

Mirja M. Wirtz ◽

Philipp Hendrix ◽

Oded Goren ◽

Lisa A. Beckett ◽

Heather R. Dicristina ◽

...

Keyword(s):

Ischemic Stroke ◽

Functional Outcome ◽

Mechanical Thrombectomy ◽

Characteristic Curve ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Nihss Score ◽

Neurological Improvement ◽

Good Functional Outcome

OBJECTIVEMechanical thrombectomy is the established treatment for acute ischemic stroke due to large vessel occlusion (LVO). The authors sought to identify early predictors of a favorable outcome in stroke patients treated with mechanical thrombectomy.METHODSConsecutive patients with ischemic stroke due to LVO who underwent mechanical thrombectomy at a Comprehensive Stroke Center in the US between 2016 and 2018 were retrospectively reviewed. Demographics, stroke and treatment characteristics, as well as functional outcome at 90 days were collected. Clinical predictors of 90-day functional outcome were assessed and compared to existing indices for prompt neurological improvement. Analyses of area under the receiver operating characteristic curve were performed to estimate the optimal thresholds for absolute 24-hour and delta (change in) National Institutes of Health Stroke Scale (NIHSS) scores for functional outcome prediction.RESULTSA total of 156 patients (median age 71.5 years) underwent 159 mechanical thrombectomies. The M1 segment of the middle cerebral artery was the most frequent site of occlusion (57.2%). The median NIHSS score before thrombectomy was 18 (IQR 14–24). A postthrombectomy Thrombolysis in Cerebral Infarction score of 2B or 3 was achieved in 147 procedures (92.4%). The median NIHSS score 24 hours after thrombectomy was 14 (IQR 6–22). Good functional outcome at 90 days (modified Rankin Scale score 0–2) was achieved in 37 thrombectomies (23.9%). An absolute 24-hour NIHSS score ≤ 10 (OR 25.929, 95% CI 8.448–79.582, p < 0.001) and a delta NIHSS score ≥ 8 between baseline and 24 hours (OR 4.929, 95% CI 2.245–10.818, p < 0.001) were associated with good functional outcome at 90 days. The 24-hour NIHSS score cutoff of 10 outperformed existing indices for prompt neurological improvement in the ability to predict 90-day functional outcome.CONCLUSIONSAn NIHSS score ≤ 10 at 24 hours after mechanical thrombectomy was independently associated with good functional outcome at 90 days.

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Burden of large vessel occlusion stroke and the service gap of thrombectomy: A population-based study using a territory-wide public hospital system registry

International Journal of Stroke ◽

10.1177/1747493019830585 ◽

2019 ◽

Vol 15 (1) ◽

pp. 69-74 ◽

Cited By ~ 1

Author(s):

Anderson C.O. Tsang ◽

Jia You ◽

Lai Fung Li ◽

Frederick C.P. Tsang ◽

Pauline P.S. Woo ◽

...

Keyword(s):

Hong Kong ◽

Ischemic Stroke ◽

Population Based ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Stroke Patients ◽

Anterior Circulation ◽

Vessel Occlusion ◽

The Public ◽

Service Gap

Background Ischemic stroke due to large vessel occlusion can be effectively treated with thrombectomy but access to this treatment is limited in many parts of the world. Local incidence of large vessel occlusion is critical in determining the development of thrombectomy service, but reliable data from Asian countries are lacking. Aims We performed a population-based study to estimate the burden of large vessel occlusion and the service gap for thrombectomy in Hong Kong. Methods All acute ischemic stroke patients admitted in 2016 to the public healthcare system, which provided 90% of the emergency healthcare in the city, was identified from the Hong Kong Hospital Authority’s central electronic database. The diagnosis of large vessel occlusion was retrospectively verified by two independent cerebrovascular specialists in a randomly sampled cohort based on clinical and neuroimaging data. The incidence of large vessel occlusion in the population was estimated through weighting the sample results and compared with the thrombectomy data in the same period. Results There were 6859 acute ischemic stroke patients treated in the public health system in 2016. Amongst the 300 patients randomly sampled according to diagnosis coding, 130 suffered from anterior circulation large vessel occlusion. This translated to 918 patients (95% CI 653–1180) and 13.3% of all ischemic stroke patients. The estimated incidence of anterior circulation large vessel occlusion was 12.5 per 100,000 persons per year (95% CI 11.7–13.4). Large vessel occlusion stroke patients were more commonly female than male (67.4% vs. 31.6%, p = 0.003), and were older than non-large vessel occlusion stroke patients (mean of 80.5 years vs. 71.4 years, p = < 0.001). They also had higher 30-day mortality rate (31.1% vs. 4.6%, p = < 0.001), and longer hospital stay (mean 38.6 vs. 21.1 days, p = 0.003) than non-large vessel occlusion stroke. In the same period, 83 thrombectomies for large vessel occlusion were performed, representing 9.1% of the estimated large vessel occlusion incidence. Conclusion The estimated incidence of anterior circulation large vessel occlusion in the Hong Kong Chinese population is lower than that in the West. There is however a substantial service gap for endovascular thrombectomy with less than 10% of large vessel occlusion patients receiving thrombectomy.

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D-dimer level and outcome of minor ischemic stroke with large vessel occlusion

Journal of the Neurological Sciences ◽

10.1016/j.jns.2020.116814 ◽

2020 ◽

Vol 413 ◽

pp. 116814 ◽

Cited By ~ 2

Author(s):

Takeo Sato ◽

Shoichiro Sato ◽

Hiroshi Yamagami ◽

Teppei Komatsu ◽

Tadataka Mizoguchi ◽

...

Keyword(s):

Ischemic Stroke ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Minor Ischemic Stroke ◽

D Dimer

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Early neurologic decline in acute ischemic stroke patients receiving thrombolysis with large vessel occlusion and mild deficits

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2020-015871 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1085-1087 ◽

Cited By ~ 1

Author(s):

Vivien H Lee ◽

Gaurav Thakur ◽

Shahid M Nimjee ◽

Patrick P Youssef ◽

Sushil Lakhani ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Nihss Score ◽

Intravenous Tissue Plasminogen Activator ◽

History Of ◽

The Mean ◽

Mean Time

BackgroundWe sought to determine the rate of early neurologic decline (END) in patients with acute ischemic stroke (AIS) with large vessel occlusion (LVO) who presented with mild deficits and received intravenous tissue plasminogen activator (IVtPA).MethodsAmong 1022 patients with AIS who received IVtPA from 2014 to 2019, we identified 313 (30.6%) with LVO, of which 94 (30%) presented with National Institute of Health Stroke Scale (NIHSS) score ≤7. Thirteen patients were excluded, leaving 81 for analysis. END was defined as NIHSS worsening of ≥4 points within 24 hours.ResultsAmong 81 patients with LVO and low NIHSS score, the mean age was 65.8 years (range 25–93) and 41% were female. The mean time to IVtPA from last known well was 2.5 hours (range 0.8–7). LVO sites were as follows: 5 (6%) carotid, 23 (28%) M1, and 53 (65%) M2 occlusions. Among the 81 patients, 28 (34.6%) had END, and these patients were older (70.8 vs 63.2 years, p=0.036). The mean change in NIHSS score at 24 hours in those with END was 10.4 (range 4–22). Patients with END were less likely to be discharged home (25% vs 66%, p=0.004).ConclusionsAmong patients with LVO AIS who received IVtPA, 30% presented with initial mild deficits. END occurred in one-third of LVO patients with initial mild deficits despite receiving IVtPA. Clinicians should be aware that the natural history of LVO with initial mild deficits is not benign and these patients are eligible for rescue thrombectomy in the 24-hour window if they deteriorate.

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Clinically Approximated Hypoperfused Tissue in Large Vessel Occlusion Stroke

Stroke ◽

10.1161/strokeaha.120.033294 ◽

2021 ◽

Author(s):

Shashvat M. Desai ◽

Santiago Ortega-Gutierrez ◽

Sunil A. Sheth ◽

Mudassir Farooqui ◽

Victor Lopez-Rivera ◽

...

Keyword(s):

Ischemic Stroke ◽

Conversion Factor ◽

Time Window ◽

Clinical Severity ◽

Large Vessel ◽

Late Time ◽

Large Vessel Occlusion ◽

Eligibility Criteria ◽

Vessel Occlusion ◽

Nihss Score

Background and Purpose: Patient selection for thrombectomy of acute ischemic stroke caused by large vessel occlusion in the delayed time window (>6 hours) is dependent on delineation of clinical-core mismatch or radiological target mismatch using perfusion imaging. Selection paradigms not involving advanced imaging and software processing may reduce time to treatment and broaden eligibility. We aim to develop a conversion factor to approximately determine the volume of hypoperfused tissue using the National Institutes of Health Stroke Scale (NIHSS) score (clinically approximated hypoperfused tissue [CAT] volume) and explore its ability to identify patients eligible for thrombectomy in the late-time window. Methods: We performed a retrospective analysis of anterior circulation large vessel occlusion strokes at 3 comprehensive stroke centers. Demographic, clinical, and imaging (computed tomography perfusion processed using RAPID, IschemaView) information was analyzed. A conversion factor, which is a multiple of the NIHSS score (for NIHSS score <10 and ≥10), was derived from an initial cohort to calculate CAT volumes. Accuracy of CAT-based thrombectomy eligibility criteria (using CAT volume instead of Tmax >6 seconds volume) was tested using DEFUSE-3 criteria (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3) eligibility as a gold standard in an independent cohort. Results: Of the 309 large vessel occlusion strokes (age, 70±14, 46% male, median NIHSS 16 [12–20]) included in this study, 38% of patients arrived beyond 6 hours of time from last known well. Conversion factors derived (derivation cohort-center A: 187) based on median values of Tmax>6 second volume for NIHSS score <10 subgroup was 15 and for NIHSS score ≥10 subgroup was 6. Subsequently calculated CAT volume–based eligibility criteria yielded a sensitivity of 100% and specificity of 92% in detecting DEFUSE-3 eligible patients (area under the curve, 0.92 [95% CI, 0.82–1]) in the validation cohort (center B and C:122). Conclusions: Clinical severity of stroke (NIHSS score) may be used to calculate the volume of hypoperfused tissue during large vessel occlusion stroke. CAT volumes for NIHSS score <10 (using a factor of 15) and ≥10 (using a factor of 6) subgroups can accurately identify DEFUSE-3-eligible patients.

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