Association of Time to Thrombolysis With Early Reperfusion After Alteplase and Tenecteplase in Patients With Large Vessel Occlusion

BACKGROUND AND OBJECTIVES

Early treatment with intravenous alteplase increases the probability of lytic-induced reperfusion in large vessel occlusion (LVO) patients. The relationship of tenecteplase-induced reperfusion and the timing of thrombolytic administration has not been explored. In this study, we performed a comparative analysis of tenecteplase and alteplase reperfusion rates and assessed their relationship to the time of thrombolytic administration.

METHODS

Patients who were initially treated with a thrombolytic within 4.5 hours of symptom onset were pooled from the Royal Melbourne Stroke Registry, EXTEND-IA, EXTEND-IA TNK, and EXTEND-IA TNK part 2 trials. The primary outcome, thrombolytic-induced reperfusion, was defined as the absence of retrievable thrombus or >50% reperfusion at initial angiographic assessment (or repeat CT perfusion/angiography). We compared the treatment effect of tenecteplase and alteplase through fixed-effects Poisson regression modelling.

RESULTS

Among 846 patients included in the primary analysis, early reperfusion was observed in 173 (20%) patients (tenecteplase: 98/470 [21%], onset-to-thrombolytic time: 132 minutes [interquartile range (IQR): 99-170], and thrombolytic-to-assessment time: 61 minutes [IQR: 39-96]; alteplase: 75/376 [19%], onset-to-thrombolytic time: 143 minutes [IQR: 105-180], thrombolytic-to-assessment time: 92 minutes [IQR: 63-144]). Earlier onset-to-thrombolytic administration times were associated with an increased probability of thrombolytic-induced reperfusion in patients treated with either tenecteplase (adjusted risk ratio [aRR] 1.05 per 15 minutes [95% confidence interval (CI) 1.00-1.12] or alteplase (aRR 1.06 per 15 minutes [95% CI 1.00-1.13]). Tenecteplase remained associated with higher rates of reperfusion vs alteplase after adjustment for onset-to-thrombolytic time, occlusion site, thrombolytic-to-assessment time, and study as a fixed effect, (adjusted incidence rate ratio: 1.41 [95% CI 1.02-1.93]). No significant treatment-by-time interaction was observed (p = 0.87).

DISCUSSION

In patients with LVO presenting within 4.5 hours of symptom onset, earlier thrombolytic administration increased successful reperfusion rates. Compared with alteplase, tenecteplase was associated with a higher probability of lytic-induced reperfusion, independent of onset-to-lytic administration times.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov Identifiers: NCT02388061, NCT03340493.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that among patients with LVO receiving a thrombolytic, reperfusion was more likely with tenecteplase than alteplase.

SF-CORNER (splenic flexure colorectal cancer): an international survey of operative approaches and outcomes for cancers of the splenic flexure

AIM

The optimum surgical approach to splenic flexure cancers (SFCs) remains uncertain. The aim of this survey was to explore the opinions of an international surgical community on the management and outcomes of SFC.

METHOD

A questionnaire was constructed comprising five sections (information about respondents; definition and prognosis of SFC; operative approach; approach in specific scenarios; outcomes) and circulated through an international dissemination committee and social media.

RESULTS

The survey received 576 responses over 4 weeks across 50 countries. There was no consensus regarding the definition of the splenic flexure, whilst the proportion of respondents who did and did not think that patients with SFC had a worse outcome was equal. The overall preferred operative approach was left hemicolectomy [203 (35.2%)], followed by segmental resection [167 (29%)], extended right hemicolectomy [126 (21.9%)] and subtotal colectomy [7 (12%)]. The stated pedicles for ligation varied between resection types and also within the same resection. One hundred and sixty-six (28.8%) respondents thought a segmental resection was associated with the worst survival and 190 (33%) thought it was associated with the best quality of life.

CONCLUSION

This survey confirms a lack of consensus across all aspects SFC treatment. The differing approaches described are likely to represent different beliefs around the variable anatomy of this region and the associated lymphatic drainage. Future studies are required to address such inconsistencies and identify the optimum surgical strategy, whilst also incorporating quality-of-life metrics and patient-reported outcomes. A one-size-fits-all approach is probably not appropriate with SFC, and a more bespoke approach is required.

What Is a Meaningful Difference When Using Infarct Volume as the Primary Outcome?: Results From the HERMES Database

BACKGROUND

Ischemic stroke lesion volume at follow-up is an important surrogate outcome for acute stroke trials. We aimed to assess which differences in 48-hour lesion volume translate into meaningful clinical differences.

METHODS

We used pooled data from 7 trials investigating the efficacy of endovascular treatment for anterior circulation large vessel occlusion in acute ischemic stroke. We assessed 48-hour lesion volume follow-up computed tomography or magnetic resonance imaging. The primary outcome was a good functional outcome, defined as modified Rankin Scale (mRS) scores of 0 to 2. We performed multivariable logistic regression to predict the probability of achieving mRS scores of 0 to 2 and determined the differences in 48-hour lesion volume that correspond to a change of 1%, 5%, and 10% in the adjusted probability of achieving mRS scores of 0 to 2.

RESULTS

In total, 1665/1766 (94.2%) patients (median age, 68 [interquartile range, 57-76] years, 781 [46.9%] female) had information on follow-up ischemic lesion volume. Computed tomography was used for follow-up imaging in 83% of patients. The median 48-hour lesion volume was 41 (interquartile range, 14-120) mL. We observed a linear relationship between 48-hour lesion volume and mRS scores of 0 to 2 for adjusted probabilities between 65% and 20%/volumes <80 mL, although the curve sloped off for lower mRS scores of 0-2 probabilities/higher volumes. The median differences in 48-hour lesion volume associated with a 1%, 5%, and 10% increase in the probability of mRS scores of 0 to 2 for volumes <80 mL were 2 (interquartile range, 2-3), 10 (9-11), and 20 (18-23) mL, respectively. We found comparable associations when assessing computed tomography and magnetic resonance imaging separately.

CONCLUSIONS

A difference of 2, 10, and 20 mL in 48-hour lesion volume, respectively, is associated with a 1%, 5%, and 10% absolute increase in the probability of achieving good functional outcome. These results can inform the design of future stroke trials that use 48-hour lesion volume as the primary outcome.

Neurological Improvement by One-Thirds Is Associated With Early Recanalization in Stroke With Large Vessel Occlusion

BACKGROUND

A proportion of large vessel occlusion strokes demonstrate early recanalization, obviating the initial intention to proceed to endovascular thrombectomy. Neurological improvement is a possible surrogate marker for reperfusion. We aimed to determine the optimal threshold of neurological improvement, as defined by the National Institutes of Health Stroke Scale (NIHSS), which best associates with early recanalization.

METHODS

We retrospectively analyzed consecutive patients with large vessel occlusion transferred from primary stroke centers to a tertiary comprehensive stroke center in Melbourne, Australia, for possible endovascular thrombectomy from January 2018 to December 2022. Absolute and percentage changes in NIHSS between transfer, as well as other definitions of neurological improvement, were compared using receiver operating characteristic curve analysis for association with recanalization as defined by the absence of occlusion in the internal carotid artery, middle cerebral artery (M1 or M2 segments), or basilar artery on repeat vascular imaging.

RESULTS

Six hundred and fifty-four transferred patients with large vessel occlusion were included in the analysis: mean age was 68.8±14.0 years, 301 (46.0%) were women, and 338 (52%) received intravenous thrombolytics. The proportion of extracranial internal carotid artery, intracranial internal carotid artery, M1, proximal M2, and basilar artery occlusion was 18.8%, 13.6%, 48.3%, 15.0%, and 4.3%, respectively, on initial computed tomography angiogram. Median NIHSSprimary stroke center and NIHSScomprehensive stroke center scores were 15 (interquartile range, 9-18) and 13 (interquartile range, 8-19), respectively. Early recanalization occurred in 82 (13%) patients. NIHSS reduction of ≥33% was the best tradeoff between sensitivity (64%) and specificity (83%) for identifying recanalization. NIHSS reduction of ≥33% had the highest discriminative ability to predict recanalization (area under the curve, 0.735) in comparison with other definitions of neurological improvement.

CONCLUSIONS

One-third neurological improvement between the primary hospital and tertiary center was the best predictor of early recanalization.

Endovascular Brain-Computer Interfaces in Poststroke Paralysis

Stroke is a leading cause of paralysis, most frequently affecting the upper limbs and vocal folds. Despite recent advances in care, stroke recovery invariably reaches a plateau, after which there are permanent neurological impairments. Implantable brain-computer interface devices offer the potential to bypass permanent neurological lesions. They function by (1) recording neural activity, (2) decoding the neural signal occurring in response to volitional motor intentions, and (3) generating digital control signals that may be used to control external devices. While brain-computer interface technology has the potential to revolutionize neurological care, clinical translation has been limited. Endovascular arrays present a novel form of minimally invasive brain-computer interface devices that have been deployed in human subjects during early feasibility studies. This article provides an overview of endovascular brain-computer interface devices and critically evaluates the patient with stroke as an implant candidate. Future opportunities are mapped, along with the challenges arising when decoding neural activity following infarction. Limitations arise when considering intracerebral hemorrhage and motor cortex lesions; however, future directions are outlined that aim to address these challenges.

Atrial fibrillation is associated with higher first pass effect following thrombectomy for large vessel occlusion

BACKGROUND

First pass effect (FPE), defined as single-pass complete or near complete reperfusion during endovascular thrombectomy (EVT) for large vessel occlusion (LVO) strokes, is a critical performance metric. Atrial fibrillation (AF)-related strokes have different clot composition compared with non-AF strokes, which may impact thrombectomy reperfusion results. We compared FPE rates in AF and non-AF stroke patients to evaluate if AF-related strokes had higher FPE rates.

METHODS

We conducted a post-hoc analysis of the DIRECT-SAFE trial data, including patients with retrievable clots on the initial angiographic run. Patients were categorized into AF and non-AF groups. The primary outcome was the presence or absence of FPE (single-pass, single-device resulting in complete/near complete reperfusion) in AF and non-AF groups. We used multivariable logistic regression to examine the association between FPE and AF, adjusting for thrombolysis pre-thrombectomy and clot location.

RESULTS

We included 253 patients (67 with AF, 186 without AF). AF patients were older (mean age: 74 years vs 67.5 years, p=0.001), had a higher proportion of females (55% vs 40%, p=0.044), and experienced more severe strokes (median National Institutes of Health Stroke Scale (NIHSS) score: 17 vs 14, p=0.009) than non-AF patients. No differences were observed in thrombolytic agent usage, time metrics, or clot location. AF patients achieved a higher proportion of FPE compared with non-AF patients (55.22% vs 37.3%, adjusted odds ratio 2.00 (95% CI 1.13 to 3.55), p=0.017).

CONCLUSIONS

AF-related strokes in LVO patients treated with EVT were associated with FPE. This highlights the need for preparedness for multiple passes and potential adjuvant/rescue therapy in non-AF-related strokes.

Occult contrast retention post-thrombectomy on 24-h follow-up dual-energy CT: Associations and impact on imaging analysis

BACKGROUND

Following reperfusion treatment in ischemic stroke, computed tomography (CT) imaging at 24 h is widely used to assess radiological outcomes. Even without visible hyperattenuation, occult angiographic contrast may persist in the brain and confound Hounsfield unit-based imaging metrics, such as net water uptake (NWU).

AIMS

We aimed to assess the presence and factors associated with retained contrast post-thrombectomy on 24-h imaging using dual-energy CT (DECT), and its impact on the accuracy of NWU as a measure of cerebral edema.

METHODS

Consecutive patients with anterior circulation large vessel occlusion who had post-thrombectomy DECT performed 24-h post-treatment from two thrombectomy stroke centers were retrospectively studied. NWU was calculated by interside comparison of HUs of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention and bilateral infarcts were excluded. Cerebral edema was measured by relative hemispheric volume (rHV) and midline shift (MLS).

RESULTS

Of 125 patients analyzed (median age 71 (IQR = 61-80), baseline National Institutes of Health Stroke Scale (NIHSS) 16 (IQR = 9.75-21)), reperfusion (defined as extended-Thrombolysis-In-Cerebral-Infarction 2b-3) was achieved in 113 patients (90.4%). Iodine-subtracted NWU was significantly higher than unadjusted NWU (17.1% vs 10.8%, p < 0.001). In multivariable median regression analysis, increased age (p = 0.024), number of passes (p = 0.006), final infarct volume (p = 0.023), and study site (p = 0.021) were independently associated with amount of retained contrast. Iodine-subtracted NWU correlated with rHV (rho = 0.154, p = 0.043) and MLS (rho = 0.165, p = 0.033) but unadjusted NWU did not (rHV rho = -0.035, p = 0.35; MLS rho = 0.035, p = 0.347).

CONCLUSIONS

Angiographic iodine contrast is retained in brain parenchyma 24-h post-thrombectomy, even without visually obvious hyperdensities on CT, and significantly affects NWU measurements. Adjustment for retained iodine using DECT is required for accurate NWU measurements post-thrombectomy. Future quantitative studies analyzing CT after thrombectomy should consider occult contrast retention.

Vitamin D status and clinical implications in the adult population of Malaysia: a position paper by the Malaysian Vitamin D Special Interest Group

PURPOSE

Vitamin D deficiency and insufficiency is common among populations globally, and in Asia and Malaysia. The purpose of this Position Paper is to propose recommendations for both clinicians and non-clinicians to promote vitamin D sufficiency in Malaysian adults. Formation of a national multisector, multidisciplinary alliance is also proposed to progress initiatives relating to safe sun exposure, adequate vitamin D intake through food fortification, and vitamin D supplementation for high-risk groups.

METHODS

Literature reviews were undertaken to inform summaries of the following: vitamin D status globally and in Asian and Malaysian populations, vitamin D status among individuals with common medical conditions, and current recommendations to achieve vitamin D sufficiency through sun exposure, food intake and supplementation. Recommendations were based on the findings of the literature reviews, recent European guidance on vitamin D supplementation, the 2018 road map for action on vitamin D in low- and middle-income countries, and research recommendations proposed by the Malaysian Ministry of Health in 2017.

RESULTS

Recommendations on assessment of vitamin D in the adult Malaysian population include using serum or plasma 25-hydroxyvitamin D concentration as a biomarker, widespread participation by Malaysian laboratories in the Vitamin D Standardization Program, adoption of the US Endocrine Society definitions of vitamin D deficiency and insufficiency, and development of a comprehensive nationwide vitamin D status study. Specific high-risk groups are identified for vitamin D assessment and recommendations relating to loading doses and ongoing management are also made.

CONCLUSION

This Position Paper provides individual clinicians and national stakeholder organisations with clear recommendations to achieve vitamin D sufficiency in the adult population of Malaysia.

Endovascular therapy in acute ischemic stroke with poor reperfusion is associated with worse outcomes compared with best medical management: a HERMES substudy

BACKGROUND

Functional outcomes in patients with acute ischemic stroke (AIS) with large vessel occlusion (LVO) undergoing endovascular treatment (EVT) with poor reperfusion were compared with patients with AIS-LVO treated with best medical management only.

METHODS

Data are from the HERMES collaboration, a patient-level meta-analysis of seven randomized EVT trials. Baseline characteristics and functional outcomes (modified Rankin Scale (mRS) score at 90 days) were compared between patients with poor reperfusion (defined as modified Thrombolysis in Cerebral Infarction Score 0-1 on the final intracranial angiography run as assessed by the central imaging core laboratory) and patients in the control arm with multivariable logistic ordinal logistic regression adjusted for pre-specified baseline variables.

RESULTS

972 of 1764 patients from the HERMES collaboration were included in the analysis: 893 in the control arm and 79 in the EVT arm with final mTICI 0-1. Patients with poor reperfusion who underwent EVT had higher baseline National Institutes of Health Stroke Scale than controls (median 19 (IQR 15.5-21) vs 17 (13-21), P=0.011). They also had worse mRS at 90 days compared with those in the control arm in adjusted analysis (median 4 (IQR 3-6) vs median 4 (IQR 2-5), adjusted common OR 0.59 (95% CI 0.38 to 0.91)). Symptomatic intracranial hemorrhage was not different between the two groups (3.9% vs 3.5%, P=0.75, adjusted OR 0.94 (95% CI 0.23 to 3.88)).

CONCLUSION

Poor reperfusion after EVT was associated with worse outcomes than best medical management, although no difference in symptomatic intracranial hemorrhage was seen. These results emphasize the need for additional efforts to further improve technical EVT success rates.

Development and Validation of a Postprocedural Model to Predict Outcome After Endovascular Treatment for Ischemic Stroke

Importance

Outcome prediction after endovascular treatment (EVT) for ischemic stroke is important to patients, family members, and physicians.

Objective

To develop and validate a model based on preprocedural and postprocedural characteristics to predict functional outcome for individual patients after EVT.

Design, Setting, and Participants

A prediction model was developed using individual patient data from 7 randomized clinical trials, performed between December 2010 and December 2014. The model was developed within the Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials (HERMES) collaboration and external validation in data from the Dutch Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry of patients treated in clinical practice between March 2014 and November 2017. Participants included patients from multiple centers throughout different countries in Europe, North America, East Asia, and Oceania (derivation cohort), and multiple centers in the Netherlands (validation cohort). Included were adult patients with a history of ischemic stroke from an intracranial large vessel occlusion in the anterior circulation who underwent EVT within 12 hours of symptom onset or last seen well. Data were last analyzed in July 2022.

Main Outcome(s) and Measure(s)

A total of 19 variables were assessed by multivariable ordinal regression to predict functional outcome (modified Rankin Scale [mRS] score) 90 days after EVT. Variables were routinely available 1 day after EVT. Akaike information criterion (AIC) was used to optimize model fit vs model complexity. Probabilities for functional independence (mRS 0-2) and survival (mRS 0-5) were derived from the ordinal model. Model performance was expressed with discrimination (C statistic) and calibration.

Results

A total of 781 patients (median [IQR] age, 67 [57-76] years; 414 men [53%]) constituted the derivation cohort, and 3260 patients (median [IQR] age, 72 [61-80] years; 1684 men [52%]) composed the validation cohort. Nine variables were included in the model: age, baseline National Institutes of Health Stroke Scale (NIHSS) score, prestroke mRS score, history of diabetes, occlusion location, collateral score, reperfusion grade, NIHSS score at 24 hours, and symptomatic intracranial hemorrhage 24 hours after EVT. External validation in the MR CLEAN Registry showed excellent discriminative ability for functional independence (C statistic, 0.91; 95% CI, 0.90-0.92) and survival (0.89; 95% CI, 0.88-0.90). The proportion of functional independence in the MR CLEAN Registry was systematically higher than predicted by the model (41% vs 34%), whereas observed and predicted survival were similar (72% vs 75%). The model was updated and implemented for clinical use.

Conclusion and relevance

The prognostic tool MR PREDICTS@24H can be applied 1 day after EVT to accurately predict functional outcome for individual patients at 90 days and to provide reliable outcome expectations and personalize follow-up and rehabilitation plans. It will need further validation and updating for contemporary patients.

Endovascular Treatment for Acute Large Vessel Occlusion Due to Underlying Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of acute ischemic stroke worldwide. Patients with acute large vessel occlusion due to underlying ICAD (ICAD-LVO) often do not achieve successful recanalization when undergoing mechanical thrombectomy (MT) alone, requiring rescue treatment, including intra-arterial thrombolysis, balloon angioplasty, and stenting. Therefore, early detection of ICAD-LVO before the procedure is important to enable physicians to select the optimal treatment strategy for ICAD-LVO to improve clinical outcomes. Early diagnosis of ICAD-LVO is challenging in the absence of consensus diagnostic criteria on noninvasive imaging and early digital subtraction angiography. In this review, we summarize the clinical and diagnostic criteria, prediction of ICAD-LVO prior to the procedure, and EVT strategy of ICAD-LVO and provide recommendations according to the current literature.

Safety and Efficacy of Tenecteplase and Alteplase in Patients With Tandem Lesion Stroke: A Post Hoc Analysis of the EXTEND-IA TNK Trials

BACKGROUND AND OBJECTIVES

The safety and efficacy of tenecteplase (TNK) in patients with tandem lesion (TL) stroke is unknown. We performed a comparative analysis of TNK and alteplase in patients with TLs.

METHODS

We first compared the treatment effect of TNK and alteplase in patients with TLs using individual patient data from the EXTEND-IA TNK trials. We evaluated intracranial reperfusion at initial angiographic assessment and 90-day modified Rankin scale (mRS) with ordinal logistic and Firth regression models. Because 2 key outcomes, mortality and symptomatic intracranial hemorrhage (sICH), were few in number among those who received alteplase in the EXTEND-IA TNK trials, we generated pooled estimates for these outcomes by supplementing trial data with estimates of incidence obtained through a meta-analysis of studies identified in a systematic review. We then calculated unadjusted risk differences to compare the pooled estimates for those receiving alteplase with the incidence observed in the trial among those receiving TNK.

RESULTS

Seventy-one of 483 patients (15%) in the EXTEND-IA TNK trials possessed a TL. In patients with TLs, intracranial reperfusion was observed in 11/56 (20%) of TNK-treated patients vs 1/15 (7%) alteplase-treated patients (adjusted odds ratio 2.19; 95% CI 0.28-17.29). No significant difference in 90-day mRS was observed (adjusted common odds ratio 1.48; 95% CI 0.44-5.00). A pooled study-level proportion of alteplase-associated mortality and sICH was 0.14 (95% CI 0.08-0.21) and 0.09 (95% CI 0.04-0.16), respectively. Compared with a mortality rate of 0.09 (95% CI 0.03-0.20) and an sICH rate of 0.07 (95% CI 0.02-0.17) in TNK-treated patients, no significant difference was observed.

DISCUSSION

Functional outcomes, mortality, and sICH did not significantly differ between patients with TLs treated with TNK and those treated with alteplase.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that TNK is associated with similar rates of intracranial reperfusion, functional outcome, mortality, and sICH compared with alteplase in patients with acute stroke due to TLs. However, the CIs do not rule out clinically important differences. TRIAL REGISTRATION INFORMATION: clinicaltrials.gov/ct2/show/NCT02388061; clinicaltrials.gov/ct2/show/NCT03340493.

Admission systolic blood pressure and effect of endovascular treatment in patients with ischaemic stroke: an individual patient data meta-analysis

BACKGROUND

Current guidelines for ischaemic stroke treatment recommend a strict, but arbitrary, upper threshold of 185/110 mm Hg for blood pressure before endovascular thrombectomy. Nevertheless, whether admission blood pressure influences the effect of endovascular thrombectomy on outcome remains unknown. Our aim was to study the influence of admission systolic blood pressure (SBP) on functional outcome and on the effect of endovascular thrombectomy.

METHODS

We used individual patient data from seven randomised controlled trials (MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, PISTE, and THRACE) that randomly assigned patients with anterior circulation ischaemic stroke to endovascular thrombectomy (predominantly using stent retrievers) or standard medical therapy (control) between June 1, 2010, and April 30, 2015. We included all patients for whom SBP data were available at hospital admission. The primary outcome was functional outcome (modified Rankin Scale) at 90 days. We assessed the association of SBP with outcome in both the endovascular thrombectomy group and the control group using multilevel regression analysis and tested for non-linearity and for interaction between SBP and effect of endovascular thrombectomy, taking into account treatment with intravenous thrombolysis.

FINDINGS

We included 1753 patients (867 assigned to endovascular thrombectomy, 886 assigned to control) after excluding 11 patients for whom SBP data were missing. We found a non-linear association between SBP and functional outcome with an inflection point at 140 mm Hg (732 [42%] of 1753 patients had SBP <140 mm Hg and 1021 [58%] had SBP ≥140 mm Hg). Among patients with SBP of 140 mm Hg or higher, admission SBP was associated with worse functional outcome (adjusted common odds ratio [acOR] 0·86 per 10 mm Hg SBP increase; 95% CI 0·81-0·91). We found no association between SBP and functional outcome in patients with SBP less than 140 mm Hg (acOR 0·97 per 10 mm Hg SBP decrease, 95% CI 0·88-1·05). There was no significant interaction between SBP and effect of endovascular thrombectomy on functional outcome (p=0·96).

INTERPRETATION

In our meta-analysis, high admission SBP was associated with worse functional outcome after stroke, but SBP did not seem to negate the effect of endovascular thrombectomy. This finding suggests that admission SBP should not form the basis for decisions to withhold or delay endovascular thrombectomy for ischaemic stroke, but randomised trials are needed to further investigate this possibility.

FUNDING

Medtronic.

Risk factors of unexplained early neurological deterioration after treatment for ischemic stroke due to large vessel occlusion: a post hoc analysis of the HERMES study

BACKGROUND

Early neurological deterioration (END) after endovascular treatment (EVT) in patients with anterior circulation acute ischemic stroke (AIS) is associated with poor outcome. END may remain unexplained by parenchymal hemorrhage (UnEND). We aim to analyze the risk factors of UnEND in the medical management (MM) and EVT arms of the HERMES study.

METHODS

We conducted a post-hoc analysis of anterior AIS patients who underwent EVT for proximal anterior occlusions. Risk factors of UnEND, defined as a worsening of ≥4 points between baseline National Institutes of Health Stroke Scale (NIHSS) and NIHSS at 24 hours without hemorrhage, were compared between both arms using mixed logistic regression models adjusted for baseline characteristics. An interaction analysis between the EVT and MM arms for risk factors of UnEND was conducted.

RESULTS

Among 1723 patients assessable for UnEND, 160 patients experienced an UnEND (9.3%), including 9.1% (78/854) in the EVT arm and 9.4% (82/869) in the MM arm. There was no significant difference in the incidence of UnEND between the two study arms. In the EVT population, independent risk factors of UnEND were lower baseline NIHSS, higher baseline glucose, and lower collateral grade. In the MM population, the only independent predictor of UnEND was higher baseline glucose. However, we did not demonstrate an interaction between EVT and MM for baseline factors as risk factors of UnEND. UnEND was, similarly in both treatment groups, a significant predictor of unfavorable outcome in both the EVT (p<0.001) and MM (p<0.001) arms.

CONCLUSIONS

UnEND is not an uncommon event, with a similar rate which ever treatment arm is considered. In the clinical scenario of AIS due to large vessel occlusion, no patient-related factor seems to increase the risk for UnEND when treated by EVT compared with MM.

Clinical outcome of patients with mild pre-stroke morbidity following endovascular treatment: a HERMES substudy

BACKGROUND

Analyses of the effect of pre-stroke functional levels on the outcome of endovascular therapy (EVT) have focused on the course of patients with moderate to substantial pre-stroke disability. The effect of complete freedom from pre-existing disability (modified Rankin Scale (mRS) 0) versus predominantly mild pre-existing disability/symptoms (mRS 1-2) has not been well delineated.

METHODS

The HERMES meta-analysis pooled data from seven randomized trials that tested the efficacy of EVT. We tested for a multiplicative interaction effect of pre-stroke mRS on the relationship between treatment and outcomes. Ordinal regression was used to assess the association between EVT and 90-day mRS (primary outcome) in the subgroup of patients with pre-stroke mRS 1-2. Multivariable regression modeling was then used to test the effect of mild pre-stroke disability/symptoms on the primary and secondary outcomes (delta-mRS, mRS 0-2/5-6) compared with patients with pre-stroke mRS 0.

RESULTS

We included 1764 patients, of whom 199 (11.3%) had pre-stroke mRS 1-2. No interaction effect of pre-stroke mRS on the relationship between treatment and outcome was observed. Patients with pre-stroke mRS 1-2 had worse outcomes than those with pre-stroke mRS 0 (adjusted common OR (acOR) 0.53, 95% CI 0.40 to 0.70). Nonetheless, a significant benefit of EVT was observed within the mRS 1-2 subgroup (cOR 2.08, 95% CI 1.22 to 3.55).

CONCLUSIONS

Patients asymptomatic/without disability prior to onset have better outcomes following EVT than patients with mild disability/symptoms. Patients with pre-stroke mRS 1-2, however, more often achieve good outcomes with EVT compared with conservative management. These findings indicate that mild pre-existing disability/symptoms influence patient prognosis after EVT but do not diminish the EVT treatment effect.

Outcome prediction in large vessel occlusion ischemic stroke with or without endovascular stroke treatment: THRIVE-EVT

INTRODUCTION

The THRIVE score and the THRIVE-c calculation are validated ischemic stroke outcome prediction tools based on patient variables that are readily available at initial presentation. Randomized controlled trials (RCTs) have demonstrated the benefit of endovascular treatment (EVT) for many patients with large vessel occlusion (LVO), and pooled data from these trials allow for adaptation of the THRIVE-c calculation for use in shared clinical decision making regarding EVT.

METHODS

To extend THRIVE-c for use in the context of EVT, we extracted data from the Virtual International Stroke Trials Archive (VISTA) from 7 RCTs of EVT. Models were built in a randomly selected development cohort using logistic regression that included the predictors from THRIVE-c: age, NIH Stroke Scale (NIHSS) score, presence of hypertension, diabetes mellitus, and/or atrial fibrillation, as well as randomization to EVT and, where available, the Alberta Stroke Program Early CT Score (ASPECTS).

RESULTS

Good outcome was achieved in 366/787 (46.5%) of subjects randomized to EVT and in 236/795 (29.7%) of subjects randomized to control (P < 0.001), and the improvement in outcome with EVT was seen across age, NIHSS, and THRIVE-c good outcome prediction. Models to predict outcome using THRIVE elements (age, NIHSS, and comorbidities) together with EVT, with or without ASPECTS, had similar performance by ROC analysis in the development and validation cohorts (THRIVE-EVT ROC area under the curve (AUC) = 0.716 in development, 0.727 in validation, P = 0.30; THRIVE-EVT + ASPECTS ROC AUC = 0.718 in development, 0.735 in validation, P = 0.12).

CONCLUSION

THRIVE-EVT may be used alongside the original THRIVE-c calculation to improve outcome probability estimation for patients with acute ischemic stroke, including patients with or without LVO, and to model the potential improvement in outcomes with EVT for an individual patient based on variables that are available at initial presentation. Online calculators for THRIVE-c estimation are available at www.thrivescore.org and www.mdcalc.com/thrive-score-for-stroke-outcome.

Perceived acceptable uncertainty regarding comparability of endovascular treatment alone versus intravenous thrombolysis plus endovascular treatment

BACKGROUND

Most trials comparing endovascular treatment (EVT) alone versus intravenous thrombolysis with alteplase (IVT) + EVT in directly admitted patients with a stroke are non-inferiority trials. However, the margin based on the level of uncertainty regarding non-inferiority of the experimental treatment that clinicians are willing to accept to incorporate EVT alone into clinical practice remains unknown.

OBJECTIVE

To characterize what experienced stroke clinicians would consider an acceptable level of uncertainty for hypothetical decisions on whether to administer IVT or not before EVT in patients admitted directly to EVT-capable centers.

METHODS

A web-based, structured survey was distributed to a cross-section of 600 academic neurologists/neurointerventionalists. For this purpose, a response framework for a hypothetical trial comparing IVT+EVT (standard of care) with EVT alone (experimental arm) was designed. In this trial, a similar proportion of patients in each arm achieved functional independence at 90 days. Invited physicians were asked at what level of certainty they would feel comfortable skipping IVT in clinical practice, considering these hypothetical trial results.

RESULTS

There were 180 respondents (response rate: 30%) and 165 with complete answers. The median chosen acceptable uncertainty suggesting reasonable comparability between both treatments was an absolute difference in the rate of day 90 functional independence of 3% (mode 5%, IQR 1-5%), with higher chosen margins observed in interventionalists (aOR 2.20, 95% CI 1.06 to 4.67).

CONCLUSION

Physicians would generally feel comfortable skipping IVT before EVT at different certainty thresholds. Most physicians would treat with EVT alone if randomized trial data suggested that the number of patients achieving functional independence at 90 days was similar between the two groups, and one could be sufficiently sure that no more than 3 out of 100 patients would not achieve functional independence at 90 days due to skipping IVT.

Tenecteplase Treatment and Thrombus Characteristics Associated With Early Reperfusion: An EXTEND-IA TNK Trials Analysis

BACKGROUND

Intracranial occlusion site, contrast permeability, and clot burden are thrombus characteristics that influence alteplase-associated reperfusion. In this study, we assessed the reperfusion efficacy of tenecteplase and alteplase in subgroups based on these characteristics in a pooled analysis of the EXTEND-IA TNK trial (Tenecteplase Versus Alteplase Before Endovascular Therapy for Ischemic Stroke).

METHODS

Patients with large vessel occlusion were randomized to treatment with tenecteplase (0.25 or 0.4 mg/kg) or alteplase before thrombectomy in hospitals across Australia and New Zealand (2015-2019). The primary outcome, early reperfusion, was defined as the absence of retrievable thrombus or >50% reperfusion on first-pass angiogram. We compared the effect of tenecteplase versus alteplase overall, and in subgroups, based on the following measured with computed tomography angiography: intracranial occlusion site, contrast permeability (measured via residual flow grades), and clot burden (measured via clot burden scores). We adjusted for covariates using mixed effects logistic regression models.

RESULTS

Tenecteplase was associated with higher odds of early reperfusion (75/369 [20%] versus alteplase: 9/96 [9%], adjusted odds ratio [aOR], 2.18 [95% CI, 1.03-4.63]). The difference between thrombolytics was notable in occlusions with low clot burden (tenecteplase: 66/261 [25%] versus alteplase: 5/67 [7%], aOR, 3.93 [95% CI, 1.50-10.33]) when compared to high clot burden lesions (tenecteplase: 9/108 [8%] versus alteplase: 4/29 [14%], aOR, 0.58 [95% CI, 0.16-2.06]; P_interaction=0.01). We did not observe an association between contrast permeability and tenecteplase treatment effect (permeability present: aOR, 2.83 [95% CI, 1.00-8.05] versus absent: aOR, 1.98 [95% CI, 0.65-6.03]; P_interaction=0.62). Tenecteplase treatment effect was superior with distal M1 or M2 occlusions (53/176 [30%] versus alteplase: 4/42 [10%], aOR, 3.73 [95% CI, 1.25-11.11]), but both thrombolytics had limited efficacy with internal carotid artery occlusions (tenecteplase 1/73 [1%] versus alteplase 1/19 [5%], aOR, 0.22 [95% CI, 0.01-3.83]; P_interaction=0.16).

CONCLUSIONS

Tenecteplase demonstrates superior early reperfusion versus alteplase in lesions with low clot burden. Reperfusion efficacy remains limited in internal carotid artery occlusions and lesions with high clot burden. Further innovation in thrombolytic therapies are required.

Tenecteplase Improves Reperfusion across Time in Large Vessel Stroke

OBJECTIVE

Tenecteplase improves reperfusion compared to alteplase in patients with large vessel occlusions. To determine whether this improvement varies across the spectrum of thrombolytic agent to reperfusion assessment times, we performed a comparative analysis of tenecteplase and alteplase reperfusion rates.

METHODS

Patients with large vessel occlusion and treatment with thrombolysis were pooled from the Melbourne Stroke Registry, and the EXTEND-IA and EXTEND-IA TNK trials. The primary outcome, thrombolytic-induced reperfusion, was defined as the absence of retrievable thrombus or >50% reperfusion at imaging reassessment. We compared the treatment effect of tenecteplase and alteplase, accounting for thrombolytic to assessment exposure times, via Poisson modeling. We compared 90-day outcomes of patients who achieved reperfusion with a thrombolytic to patients who achieved reperfusion via endovascular therapy using ordinal logistic regression.

RESULTS

Among 893 patients included in the primary analysis, thrombolytic-induced reperfusion was observed in 184 (21%) patients. Tenecteplase was associated with higher rates of reperfusion (adjusted incidence rate ratio [aIRR] = 1.50, 95% confidence interval [CI] = 1.09-2.07, p = 0.01). Findings were consistent in patient subgroups with first segment (aIRR = 1.41, 95% CI = 0.93-2.14) and second segment (aIRR = 2.07, 95% CI = 0.98-4.37) middle cerebral artery occlusions. Increased thrombolytic to reperfusion assessment times were associated with reperfusion (tenecteplase: adjusted risk ratio [aRR] = 1.08 per 15 minutes, 95% CI = 1.04-1.13 vs alteplase: aRR = 1.06 per 15 minutes, 95% CI = 1.00-1.13). No significant treatment-by-time interaction was observed (p = 0.87). Reperfusion via thrombolysis was associated with improved 90-day modified Rankin Scale scores (adjusted common odds ratio = 2.15, 95% CI = 1.54-3.01) compared to patients who achieved reperfusion following endovascular therapy.

INTERPRETATION

Tenecteplase, compared to alteplase, increases prethrombectomy reperfusion, regardless of the time from administration to reperfusion assessment. Prethrombectomy reperfusion is associated with better clinical outcomes. ANN NEUROL 2023;93:489-499.

Association of Endovascular Thrombectomy vs Medical Management With Functional and Safety Outcomes in Patients Treated Beyond 24 Hours of Last Known Well: The SELECT Late Study

Importance

The role of endovascular thrombectomy is uncertain for patients presenting beyond 24 hours of the time they were last known well.

Objective

To evaluate functional and safety outcomes for endovascular thrombectomy (EVT) vs medical management in patients with large-vessel occlusion beyond 24 hours of last known well.

Design, Setting, and Participants

This retrospective observational cohort study enrolled patients between July 2012 and December 2021 at 17 centers across the United States, Spain, Australia, and New Zealand. Eligible patients had occlusions in the internal carotid artery or middle cerebral artery (M1 or M2 segment) and were treated with EVT or medical management beyond 24 hours of last known well.

Interventions

Endovascular thrombectomy or medical management (control).

Main Outcomes and Measures

Primary outcome was functional independence (modified Rankin Scale score 0-2). Mortality and symptomatic intracranial hemorrhage (sICH) were safety outcomes. Propensity score (PS)-weighted multivariable logistic regression analyses were adjusted for prespecified clinical characteristics, perfusion parameters, and/or Alberta Stroke Program Early CT Score (ASPECTS) and were repeated in subsequent 1:1 PS-matched cohorts.

Results

Of 301 patients (median [IQR] age, 69 years [59-81]; 149 female), 185 patients (61%) received EVT and 116 (39%) received medical management. In adjusted analyses, EVT was associated with better functional independence (38% vs control, 10%; inverse probability treatment weighting adjusted odds ratio [IPTW aOR], 4.56; 95% CI, 2.28-9.09; P < .001) despite increased odds of sICH (10.1% for EVT vs 1.7% for control; IPTW aOR, 10.65; 95% CI, 2.19-51.69; P = .003). This association persisted after PS-based matching on (1) clinical characteristics and ASPECTS (EVT, 35%, vs control, 19%; aOR, 3.14; 95% CI, 1.02-9.72; P = .047); (2) clinical characteristics and perfusion parameters (EVT, 35%, vs control, 17%; aOR, 4.17; 95% CI, 1.15-15.17; P = .03); and (3) clinical characteristics, ASPECTS, and perfusion parameters (EVT, 45%, vs control, 21%; aOR, 4.39; 95% CI, 1.04-18.53; P = .04). Patients receiving EVT had lower odds of mortality (26%) compared with those in the control group (41%; IPTW aOR, 0.49; 95% CI, 0.27-0.89; P = .02).

Conclusions and Relevance

In this study of treatment beyond 24 hours of last known well, EVT was associated with higher odds of functional independence compared with medical management, with consistent results obtained in PS-matched subpopulations and patients with presence of mismatch, despite increased odds of sICH. Our findings support EVT feasibility in selected patients beyond 24 hours. Prospective studies are warranted for confirmation.

Abstract TMP54: Increased Thrombectomy Time Saving From Melbourne Mobile Stroke Unit Operation During Covid-19 Pandemic

Introduction: Mobile stroke units (MSU) have demonstrated major time savings for thrombolysis but mixed evidence for endovascular thrombectomy (EVT). COVID-19 precautions have dramatically slowed EVT workflows across Australia and we therefore aimed to examine the effect of the Melbourne MSU on thrombectomy times before and during the current pandemic.

Methods: Patients receiving EVT facilitated by the Melbourne MSU from 2017-2021 were compared to non-MSU patients (metropolitan direct and secondary transfer for EVT) admitted to the largest Melbourne EVT centre. Quantile regression analysis was used to calculate the median time difference (50 th quantile) between MSU and non-MSU patients before and during the pandemic, grouped by patients within an EVT centre ambulance catchment or those outside (who either received inter-hospital transfer or MSU-facilitated bypass to an EVT centre).

Results: A total of 402 patients (112 MSU) were included. Pre-pandemic, no reduction in dispatch to arterial access time was seen for MSU patients within an EVT centre catchment (median 11min slower, p=0.38). However, a significant time saving was observed during the pandemic (median 29 min faster, p<0.001, p-interaction=0.0065). MSU care reduced hospital arrival to arterial access time by median 19min pre-pandemic vs 40 min during the pandemic, p-interaction<0.001). The pandemic did not alter MSU-related time savings for patients located outside of an EVT centre catchment.

Conclusions: Melbourne MSU facilitation of EVT during the COVID-19 pandemic resulted in greater time savings for patients located close to a thrombectomy centre, while substantial time savings were maintained for those needing bypass from the local non-EVT hospital. This suggests that MSU operation enables streamlined EVT workflows during the pandemic by providing early pre-hospital notification and interventional angiography activation.

Abstract WMP47: Low Sensitivity Of Widely Used Emergency Dispatch Algorithm For Thrombectomy Patients - Implications For Mobile Stroke Units

Introduction: Widely used emergency dispatch algorithms such as the Advanced Medical Priority Dispatch System (AMPDS) have limited diagnostic accuracy for prehospital diagnosis of stroke. With advent of mobile stroke units (MSU), this inaccuracy prevents optimal dispatch to patients who may benefit. Expedited endovascular thrombectomy (EVT) is a major contributor to net benefit of MSUs. We assessed the accuracy of AMPDS for recognizing stroke in thrombectomy patients in the Australian state of Victoria.

Methods: We included consecutive patients accepted for EVT (direct and secondary transfer) to The Royal Melbourne Hospital from 2007-2021 in whom linked AMPDS dispatch codes could be obtained from Ambulance Victoria. The primary outcome was the proportion of cases dispatched as stroke vs non-stroke with subgroup analyses of the effect of baseline clinical severity, metropolitan vs rural dispatch and time to thrombectomy. Chi square and Mann Whitney tests were used as appropriate.

Results: A total of n=618 patients were included with baseline NIHSS 16 (IQR 10-20). Of these, only 62% (95% CI 58-66) were initially dispatched as suspected stroke, with the most common non-stroke diagnoses being “Unconscious/Fainting” (19.2%) and “Falls” (6.9%). Those with a higher baseline severity (NIHSS ≥10) were less likely to be classified as stroke than those with lower severity (59% vs 76%, p<0.001), while no difference was found between metropolitan and rural patients (p=0.066). Overall, no significant time differences were found between stroke and non-stroke dispatches for ambulance dispatch to arterial access (median 208 vs 216 min, p=0.593) or hospital arrival to arterial access (median 42 vs 42 min, p=0.851). However, only 32 patients were treated on the MSU, which commenced operation November 2017.

Conclusions: Almost 40% of thrombectomy patients did not receive an initial AMPDS dispatch of suspected stroke and those with higher baseline severity were more likely to be misclassified. Although time to thrombectomy was not significantly different between stroke vs non-stroke dispatches, MSU treatment was under-represented. Our findings have implications for emergency medical services and particularly mobile stroke units which rely on accurate stroke dispatch.

Abstract WMP49: Occult Contrast Retention Post-thrombectomy On 24-hour Follow-up CT: Associations And Impact On Imaging Analysis

Introduction: CT performed 24h post-treatment is widely used to assess radiological outcomes in stroke studies. Even without visible hyperattenuation, occult angiographic contrast may persist in the brain and confound Hounsfield Unit-based imaging metrics such as Net Water Uptake (NWU), a measure of cerebral edema based on tissue hypoattenuation. We aimed to assess (1) the presence of retained contrast post-thrombectomy on 24h CT by comparing NWU measurements with and without adjustment for iodine using dual energy CT (DECT), (2) factors associated with amount of retention, and (3) its impact on the accuracy of NWU.

Methods: In a prospective study of patients with anterior circulation large vessel occlusion who had post-thrombectomy follow-up DECT performed 24h post-treatment from two Comprehensive Stroke Centres (November 2021 to May 2022), NWU was calculated by interside comparison of Hounsfield Units of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. We tested correlation between NWU and tissue swelling using relative hemispheric volume (rHV) and midline shift (MLS). Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention, and bilateral infarcts were excluded.

Results: Of 125 patients analysed (median age 71 [IQR 61-80], baseline NIHSS 16 [IQR 9.75-21]), reperfusion (eTICI 2b-3) was achieved in 120 patients (96.8%). NWU measured with iodine adjustment was significantly higher than NWU measured without adjustment (17.1% vs 10.8%, p<0.001). In multivariable median regression analysis, age (p=0.031), number of passes (p<0.001) and having CT perfusion at baseline (p=0.008) were independently associated with amount of retained contrast. NWU measured with iodine adjustment correlated with rHV (p=0.043) and MLS (p=0.033), but NWU without adjustment did not (rHV p=0.350; MLS p=0.347).

Conclusion: Occult angiographic iodine contrast significantly affects NWU on CT at 24h. Our data suggest adjustment for retained iodine using DECT is required for accurate NWU measures post-thrombectomy. Future studies analysing CT post-thrombectomy should consider the significance of occult contrast retention.

Abstract 92: Tenecteplase Treatment And Thrombus Characteristics Associated With Early Reperfusion - An EXTEND-IA TNK Trials Analysis

Background: Intracranial occlusion site, contrast permeability, and clot burden are thrombus characteristics that influence alteplase-associated reperfusion. In this study, we assessed the reperfusion efficacy of tenecteplase and alteplase in subgroups based on these characteristics in a pooled analysis of the EXTEND-IA TNK trials.

Methods: Patients with large vessel occlusion (LVO) were randomized to treatment with tenecteplase (0.25mg/kg or 0.4mg/kg) or alteplase (0.9mg/kg) prior to thrombectomy. The primary outcome, early reperfusion, was defined as the absence of retrievable thrombus or >50% reperfusion on initial angiographic assessment. We compared the treatment effect of tenecteplase versus alteplase overall, and in subgroups based on intracranial occlusion site, the presence of contrast permeability (measured via residual flow grades), and clot burden (measured via clot burden scores), whilst adjusting for relevant covariates using mixed effects logistic regression models.

Results: Among the 465 patients in the primary analysis, early reperfusion occurred in 18% (84/465). Tenecteplase was associated with a higher odds of early reperfusion (tenecteplase: 75/369 [20%] vs. alteplase: 9/96 [9%], aOR: 2.18 [95%CI: 1.03-4.63]). The difference between thrombolytics was most notable in distal M1 or M2 occlusions (tenecteplase: 53/176 [30%] vs. alteplase: 4/42 [10%], aOR: 3.73 [95%CI: 1.25-11.11]), thrombi with contrast permeability (tenecteplase: 38/160 [24%] vs. alteplase: 5/48 [10%], aOR: 2.83 [95%CI: 1.00-8.05]), and in low clot burden occlusions (tenecteplase: 66/261 [25%] vs. alteplase: 5/67 [7%], aOR: 3.93 [95%CI: 1.50-10.33]). Both thrombolytics had limited early reperfusion efficacy in proximal occlusions (ICA: tenecteplase 1/73 [1%] vs. alteplase 1/19 [5%]) and in high clot burden occlusions (tenecteplase: 9/108 [8%] vs. alteplase: 4/29 [14%], aOR: 0.58 [95%CI: 0.16-2.06]).

Conclusions: Tenecteplase demonstrates superior early reperfusion versus alteplase in distal LVO, in contrast-permeable thrombi, and in lesions with low clot burden. Reperfusion efficacy remains limited in ICA occlusions and lesions with high clot burden. Further improvements in intravenous thrombolytics are required.

Thrombectomy Outcomes With General vs Nongeneral Anesthesia: A Pooled Patient-Level Analysis From the EXTEND-IA Trials and SELECT Study

BACKGROUND AND OBJECTIVES

The effect of anesthesia choice on endovascular thrombectomy (EVT) outcomes is unclear. Collateral status on perfusion imaging may help identify the optimal anesthesia choice.

METHODS

In a pooled patient-level analysis of EXTEND-IA, EXTEND-IA TNK, EXTEND-IA TNK part II, and SELECT, EVT functional outcomes (modified Rankin Scale score distribution) were compared between general anesthesia (GA) vs non-GA in a propensity-matched sample. Furthermore, we evaluated the association of collateral flow on perfusion imaging, assessed by hypoperfusion intensity ratio (HIR) - Tmax > 10 seconds/Tmax > 6 seconds (good collaterals - HIR < 0.4, poor collaterals - HIR ≥ 0.4) on the association between anesthesia type and EVT outcomes.

RESULTS

Of 725 treated with EVT, 299 (41%) received GA and 426 (59%) non-GA. The baseline characteristics differed in presentation National Institutes of Health Stroke Scale score (median [interquartile range] GA: 18 [13-22], non-GA: 16 [11-20], p < 0.001) and ischemic core volume (GA: 15.0 mL [3.2-38.0] vs non-GA: 9.0 mL [0.0-31.0], p < 0.001). In addition, GA was associated with longer last known well to arterial access (203 minutes [157-267] vs 186 minutes [138-252], p = 0.002), but similar procedural time (35.5 minutes [23-59] vs 34 minutes [22-54], p = 0.51). Of 182 matched pairs using propensity scores, baseline characteristics were similar. In the propensity score-matched pairs, GA was independently associated with worse functional outcomes (adjusted common odds ratio [adj. cOR]: 0.64, 95% CI: 0.44-0.93, p = 0.021) and higher neurologic worsening (GA: 14.9% vs non-GA: 8.9%, aOR: 2.10, 95% CI: 1.02-4.33, p = 0.045). Patients with poor collaterals had worse functional outcomes with GA (adj. cOR: 0.47, 95% CI: 0.29-0.76, p = 0.002), whereas no difference was observed in those with good collaterals (adj. cOR: 0.93, 95% CI: 0.50-1.74, p = 0.82), p interaction: 0.07. No difference was observed in infarct growth overall and in patients with good collaterals, whereas patients with poor collaterals demonstrated larger infarct growth with GA with a significant interaction between collaterals and anesthesia type on infarct growth rate (p interaction: 0.020).

DISCUSSION

GA was associated with worse functional outcomes after EVT, particularly in patients with poor collaterals in a propensity score-matched analysis from a pooled patient-level cohort from 3 randomized trials and 1 prospective cohort study. The confounding by indication may persist despite the doubly robust nature of the analysis. These findings have implications for randomized trials of GA vs non-GA and may be of utility for clinicians when making anesthesia type choice.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that use of GA is associated with worse functional outcome in patients undergoing EVT.

TRIAL REGISTRATION INFORMATION

EXTEND-IA: ClinicalTrials.gov (NCT01492725); EXTEND-IA TNK: ClinicalTrials.gov (NCT02388061); EXTEND-IA TNK part II: ClinicalTrials.gov (NCT03340493); and SELECT: ClinicalTrials.gov (NCT02446587).

Door-in-door-out times for patients with large vessel occlusion ischaemic stroke being transferred for endovascular thrombectomy: a Victorian state-wide study

Background

Time to reperfusion is an important predictor of outcome in ischaemic stroke from large vessel occlusion (LVO). For patients requiring endovascular thrombectomy (EVT), the transfer times from peripheral hospitals in metropolitan and regional Victoria, Australia to comprehensive stroke centres (CSCs) have not been studied.

Aims

To determine transfer and journey times for patients with LVO stroke being transferred for consideration of EVT.

Methods

All patients transferred for consideration of EVT to three Victorian CSCs from January 2017 to December 2018 were included. Travel times were obtained from records matched to Ambulance Victoria and the referring centre via Victorian Stroke Telemedicine or hospital medical records. Metrics of interest included door-in-door-out time (DIDO), inbound journey time and outbound journey time.

Results

Data for 455 transferred patients were obtained, of which 395 (86.8%) underwent EVT. The median DIDO was 107 min (IQR 84-145) for metropolitan sites and 132 min (IQR 108-167) for regional sites. At metropolitan referring hospitals, faster DIDO was associated with use of the same ambulance crew to transport between hospitals (75 (63-90) vs 124 (99-156) min, p<0.001) and the administration of thrombolysis prior to transfer (101 (79-133) vs 115 (91-155) min, p<0.001). At regional centres, DIDO was consistently longer when patients were transported by air (160 (127-195) vs 116 (100-144) min, p<0.001). The overall door-to-door time by air was shorter than by road for sites located more than 250 km away from the CSC.

Conclusion

Transfer times differ significantly for regional and metropolitan patients. A state-wide database to prospectively collect data on all interhospital transfers for EVT would be helpful for future study of optimal transport mode at regional sites and benchmarking of DIDO across the state.

Peripheral Ophthalmic Artery Aneurysm Associated with Multifocal Intracranial and Extracranial Aneurysms: Case Report and Literature Review

Peripheral ophthalmic artery aneurysm is a rare disease entity. We review the relevant literature and report a case of fusiform aneurysm involving the entire intraorbital ophthalmic artery in association with multiple intracranial and extracranial aneurysms, diagnosed on digital subtraction angiography. The patient suffered irreversible blindness secondary to compressive optic neuropathy which did not improve after a 3-day trial of intravenous methylprednisolone. Autoimmune screen was normal. The underlying cause is unknown.

Mediation of Successful Reperfusion Effect through Infarct Growth and Cerebral Edema: A Pooled, Patient-Level Analysis of EXTEND-IA Trials and SELECT Prospective Cohort

OBJECTIVE

Reperfusion therapy is highly beneficial for ischemic stroke. Reduction in both infarct growth and edema are plausible mediators of clinical benefit with reperfusion. We aimed to quantify these mediators and their interrelationship.

METHODS

In a pooled, patient-level analysis of the EXTEND-IA trials and SELECT study, we used a mediation analysis framework to quantify infarct growth and cerebral edema (midline shift) mediation effect on successful reperfusion (modified Treatment in Cerebral Ischemia ≥ 2b) association with functional outcome (modified Rankin Scale distribution). Furthermore, we evaluated an additional pathway to the original hypothesis, where infarct growth mediated successful reperfusion effect on midline shift.

RESULTS

A total 542 of 665 (81.5%) eligible patients achieved successful reperfusion. Baseline clinical and imaging characteristics were largely similar between those achieving successful versus unsuccessful reperfusion. Median infarct growth was 12.3ml (interquartile range [IQR] = 1.8-48.4), and median midline shift was 0mm (IQR = 0-2.2). Of 249 (37%) demonstrating a midline shift of ≥1mm, median shift was 2.75mm (IQR = 1.89-4.21). Successful reperfusion was associated with reductions in both predefined mediators, infarct growth (β = -1.19, 95% confidence interval [CI] = -1.51 to -0.88, p < 0.001) and midline shift (adjusted odds ratio = 0.36, 95% CI = 0.23-0.57, p < 0.001). Successful reperfusion association with improved functional outcome (adjusted common odds ratio [acOR] = 2.68, 95% CI = 1.86-3.88, p < 0.001) became insignificant (acOR = 1.39, 95% CI = 0.95-2.04, p = 0.094) when infarct growth and midline shift were added to the regression model. Infarct growth and midline shift explained 45% and 34% of successful reperfusion effect, respectively. Analysis considering an alternative hypothesis demonstrated consistent results.

INTERPRETATION

In this mediation analysis from a pooled, patient-level cohort, a significant proportion (~80%) of successful reperfusion effect on functional outcome was mediated through reduction in infarct growth and cerebral edema. Further studies are required to confirm our findings, detect additional mediators to explain successful reperfusion residual effect, and identify novel therapeutic targets to further enhance reperfusion benefits. ANN NEUROL 2023.

Comparison of Three Scores of Collateral Status for Their Association With Clinical Outcome: The HERMES Collaboration

BACKGROUND

Leptomeningeal collateral status on baseline computed tomographic angiography (CTA) is associated with clinical outcome after acute ischemic stroke treatment. However, assessment of collateral status is not uniform. To compare 3 different CTA collateral scores (CS) and imaging techniques about their association with clinical outcome.

METHODS

Pooled analysis of patient-level data from the Highly Effective Reperfusion Using Multiple Endovascular Devices collaboration. Patients with large vessel occlusion from 7 randomized controlled trials that compared endovascular thrombectomy with standard medical care were included. Three different CS (Tan CS, regional CS [rCS], and regional Alberta Stroke Program Early CT Score CS) and 2 imaging techniques (single-phase [sCTA] and multiphase/dynamic CTA) were evaluated. Functional independence (modified Rankin Scale score 0-2) at 3 months poststroke was the primary outcome. Furthermore, we assessed the effect of sCTA image acquisition time on collateral status assessment using an adjusted ordinal logistic regression model to obtain predicted values for the trichotomized rCS.

RESULTS

Among 1147 pooled patients, 948 (82.7%) had sCTA and 199 (17.3%) multiphase/dynamic CTA as baseline angiography. With all 3 collateral scales, better CSs were associated with better 3-month functional outcome. With sCTA images, the rCS (area under the curve [AUC] 0.63) and regional Alberta Stroke Program Early CT Score CS (AUC 0.62) better predicted functional outcome than the Tan CS (AUC 0.60, respectively; P<0.001 and P=0.02). With multiphase/dynamic CTA images, all collateral scales performed similarly in predicting functional outcome (rCS [AUC 0.61]; regional Alberta Stroke Program Early CT Score CS [AUC 0.61] versus Tan CS [AUC 0.61], respectively; P=0.93 and P=0.91). Overall, no endovascular thrombectomy treatment effect modification by collateral status (rCS) was demonstrated (P=0.41). sCTA timing independently influenced CS assessment. On earlier timed sCTA, the predicted proportions of scans with poor collaterals was higher and vice versa.

CONCLUSIONS

In this data set of highly selected patients with stroke, using a regional CS on sCTA likely allows for the most accurate prediction of functional outcome while on time-resolved CTA, the type of CS did not matter. Patients across all collateral grades benefit from endovascular thrombectomy. sCTA timing independently influenced CS assessment.

Angiographic Systems for Classifying Distal Arterial Occlusions

<b><i>Background:</i></b> Extensive randomized controlled clinical trials for endovascular thrombectomy in anterior circulation large vessel occlusions (internal carotid arteries and M1 segment of middle cerebral arteries) have been published over the past decade, but there have not been randomized controlled trials for distal arterial occlusions to date. Distal arterial occlusion randomized controlled trials are essential to decide on patient selection, imaging criteria, and endovascular approach to improve the outcome and reduce complications. <b><i>Summary:</i></b> The definition of distal arterial occlusion is however unclear, and we believe that a uniform nomenclature of distal arterial occlusions is essential for the design of robust randomized controlled studies. We undertook a systematic literature review and comprehensive analysis of 70 articles looking at distal arterial occlusions and previous attempts at classifying them as well as comparing their similarities and differences with a more selective look at the middle cerebral artery. Thirty-two articles were finally deemed suitable and included for this review. In this review article, we present 3 disparate classifications of distal arterial occlusions, namely, classical/anatomical, functional/imaging, and structural/calibre, and compare the similarities and differences between them. <b><i>Key Messages:</i></b> We propose the adoption of functional/imaging classification to guide the identification of distal arterial occlusions with the M2 segment starting at the point of bifurcation of the middle cerebral artery trunk/M1 segment. With regards to the anterior temporal artery, we propose that it will be considered a branch of the M1 and only be considered as the M2 segment if it is a holo-temporal artery. We believe that this is a practical method of classification in the time-critical decision-making period.

Significance of Baseline Ischemic Core Volume on Stroke Outcome After Endovascular Therapy in Patients Age ≥75 Years: A Pooled Analysis of Individual Patient Data From 7 Trials

Background:

Age and infarct volume are strong predictors of outcome in patients with ischemic stroke who underwent endovascular therapy (EVT). We aimed to investigate the impact of ischemic core volume (ICV) on stroke outcome after EVT in elderly.

Methods:

Using the HERMES (Highly Effective Reperfusion Using Multiple Endovascular Devices) collaboration, a patient-level meta-analysis of 7 randomized trials in which patients were enrolled from December 2010 to April 2015) dataset, we categorized patients into those aged <75 and ≥75 years. ICV was calculated on computed tomography perfusion or magnetic resonance diffusion-weighted imaging. The association between ICV and the benefit of EVT over best medical treatment on outcome (modified Rankin Scale [mRS] at 90 days) and an ICV threshold for high likelihood (≥90%) of very poor outcome (mRS score ≥5) after EVT were investigated.

Results:

A total of 899 patients who had baseline ICV data, 247 patients aged ≥75 years, of which 118 were randomized in the EVT arm. Patients aged ≥75 years required smaller ICV to achieve mRS score ≤3 than those aged <75 years in the EVT arm (median 10.7 mL versus 23.9 mL, P <0.001). In patients aged ≥75 years, modeling of outcome in both treatment arms revealed potential loss of effect for EVT at ICV of ≥50 mL or ≥85 mL for achieving mRS score ≤3 or ≤4, respectively. Treatment effect of EVT was significant in ICV <50 mL for mRS ≤3 (odds ratio 2.38, 95% confidence interval 1.35–4.22). ICV ≥132 mL was a threshold for high likelihood of very poor outcome after EVT. However, EVT still predicted at least 30% rate of mRS ≤3 at 150 mL ICV if near-complete or complete reperfusion was achieved.

Conclusions:

Baseline ICV has an impact on stroke outcome after EVT in the elderly, but elderly patients with large ICV may still benefit from EVT if near-complete or complete reperfusion is achieved. Young patients seem to benefit from EVT regardless of ICV status.

Thrombectomy versus Medical Management in Mild Strokes due to Large Vessel Occlusion: Exploratory Analysis from the EXTEND-IA Trials and a Pooled International Cohort

OBJECTIVE

This study was undertaken to evaluate functional and safety outcomes for endovascular thrombectomy (EVT) versus medical management (MM) in patients with large vessel occlusion (LVO) and mild neurological deficits, stratified by perfusion imaging mismatch.

METHODS

The pooled cohort consisted of patients with National Institutes of Health Stroke Scale (NIHSS) < 6 and internal carotid artery (ICA), M1, or M2 occlusions from the Extending the Time for Thrombolysis in Emergecy Neurological Deficits - Intra-Arterial (EXTEND-IA) Trial,  Tenecteplase vs Alteplase before Endovascular Thrombectomy in Ischemic Stroke (EXTEND-IA TNK) trials Part I/II and prospective data from 15 EVT centers from October 2010 to April 2020. RAPID software estimated ischemic core and mismatch. Patients receiving primary EVT (EVT_pri ) were compared to those who received primary MM (MM_pri ), including those who deteriorated and received rescue EVT, in overall and propensity score (PS)-matched cohorts. Patients were stratified by target mismatch (mismatch ratio ≥ 1.8 and mismatch volume ≥ 15ml). Primary outcome was functional independence (90-day modified Rankin Scale = 0-2). Secondary outcomes included safety (symptomatic intracerebral hemorrhage [sICH], neurological worsening, and mortality).

RESULTS

Of 540 patients, 286 (53%) received EVT_pri and demonstrated larger critically hypoperfused tissue (Tmax > 6 seconds) volumes (median [IQR]: 64 [26-96] ml vs MM_pri : 40 [14-76] ml, p < 0.001) and higher presentation NIHSS (median [IQR]: 4 [2-5] vs MM_pri : 3 [2-4], p < 0.001). Functional independence was similar (EVT_pri : 77.4% vs MM_pri : 75.6%, adjusted odds ratio [aOR] = 1.29, 95% confidence interval [CI] = 0.82-2.03, p = 0.27). EVT had worse safety regarding sICH (EVT_pri : 16.3% vs MM_pri : 1.3%, p < 0.001) and neurological worsening (EVT_pri : 19.6% vs MM_pri : 6.7%, p < 0.001). In 414 subjects (76.7%) with target mismatch, EVT was associated with improved functional independence (EVT_pri : 77.4% vs MM_pri : 72.7%, aOR = 1.68, 95% CI = 1.01-2.81, p = 0.048), whereas there was a trend toward less favorable outcomes with primary EVT (EVT_pri : 77.4% vs MM_pri : 83.3%, aOR = 0.39, 95% CI = 0.12-1.34, p = 0.13) without target mismatch (p_interaction  = 0.06). Similar findings were observed in a propensity score-matched subpopulation.

INTERPRETATION

Overall, EVT was not associated with improved clinical outcomes in mild strokes due to LVO, and sICH was increased. However, in patients with target mismatch profile, EVT was associated with increased functional independence. Perfusion imaging may be helpful to select mild stroke patients for EVT. ANN NEUROL 2022;92:364-378.

Endovascular thrombectomy versus standard bridging thrombolytic with endovascular thrombectomy within 4·5 h of stroke onset: an open-label, blinded-endpoint, randomised non-inferiority trial

BACKGROUND

The benefit of combined treatment with intravenous thrombolysis before endovascular thrombectomy in patients with acute ischaemic stroke caused by large vessel occlusion remains unclear. We hypothesised that the clinical outcomes of patients with stroke with large vessel occlusion treated with direct endovascular thrombectomy within 4·5 h would be non-inferior compared with the outcomes of those treated with standard bridging therapy (intravenous thrombolysis before endovascular thrombectomy).

METHODS

DIRECT-SAFE was an international, multicentre, prospective, randomised, open-label, blinded-endpoint trial. Adult patients with stroke and large vessel occlusion in the intracranial internal carotid artery, middle cerebral artery (M1 or M2), or basilar artery, confirmed by non-contrast CT and vascular imaging, and who presented within 4·5 h of stroke onset were recruited from 25 acute-care hospitals in Australia, New Zealand, China, and Vietnam. Eligible patients were randomly assigned (1:1) via a web-based, computer-generated randomisation procedure stratified by site of baseline arterial occlusion and by geographic region to direct endovascular thrombectomy or bridging therapy. Patients assigned to bridging therapy received intravenous thrombolytic (alteplase or tenecteplase) as per standard care at each site; endovascular thrombectomy was also per standard of care, using the Trevo device (Stryker Neurovascular, Fremont, CA, USA) as first-line intervention. Personnel assessing outcomes were masked to group allocation; patients and treating physicians were not. The primary efficacy endpoint was functional independence defined as modified Rankin Scale score 0-2 or return to baseline at 90 days, with a non-inferiority margin of -0·1, analysed by intention to treat (including all randomly assigned and consenting patients) and per protocol. The intention-to-treat population was included in the safety analyses. The trial is registered with ClinicalTrials.gov, NCT03494920, and is closed to new participants.

FINDINGS

Between June 2, 2018, and July 8, 2021, 295 patients were randomly assigned to direct endovascular thrombectomy (n=148) or bridging therapy (n=147). Functional independence occurred in 80 (55%) of 146 patients in the direct thrombectomy group and 89 (61%) of 147 patients in the bridging therapy group (intention-to-treat risk difference -0·051, two-sided 95% CI -0·160 to 0·059; per-protocol risk difference -0·062, two-sided 95% CI -0·173 to 0·049). Safety outcomes were similar between groups, with symptomatic intracerebral haemorrhage occurring in two (1%) of 146 patients in the direct group and one (1%) of 147 patients in the bridging group (adjusted odds ratio 1·70, 95% CI 0·22-13·04) and death in 22 (15%) of 146 patients in the direct group and 24 (16%) of 147 patients in the bridging group (adjusted odds ratio 0·92, 95% CI 0·46-1·84).

INTERPRETATION

We did not show non-inferiority of direct endovascular thrombectomy compared with bridging therapy. The additional information from our study should inform guidelines to recommend bridging therapy as standard treatment.

FUNDING

Australian National Health and Medical Research Council and Stryker USA.

Functional Outcomes of Patients ≥85 Years With Acute Ischemic Stroke Following EVT: A HERMES Substudy

BACKGROUND

Observational studies have shown endovascular treatment (EVT) for acute ischemic stroke to be effective in the elderly, despite resulting in poorer outcomes and higher rates of mortality compared with younger patients. Randomized data on the effect of advanced age on outcomes following EVT are, however, lacking. Our aim was to assess the EVT effect for ischemic stroke in patients aged ≥85 years and the influence of age on outcome in a large, randomized trial dataset.

METHODS

Data were from the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) collaboration, a meta-analysis of 7 randomized trials published between January 1, 2010, and May 31, 2017, that tested the efficacy of EVT. A possible multiplicative interaction effect of age on the relationship between treatment and outcome was investigated. Ordinal logistic regression tested the association between EVT and 90-day functional outcome (modified Rankin Scale, primary outcome) in patients ≥85 years. Multivariable binary logistic regression was performed to compare primary and secondary outcomes (modified Rankin Scale score of 0-2/5-6) of patients ≥85 years versus those <85 years.

RESULTS

We included 1764 patients in the analysis, of whom 77 (4.4%) were ≥85 years old. A significant interaction of age and treatment on poor outcome (modified Rankin Scale score of 5-6, P=0.020) and mortality (P=0.031) was observed, with older adults having worse functional outcomes at 90 days compared with younger patients (adjusted common odds ratio, 0.20 [95% CI, 0.13-0.33]). However, a benefit of EVT was observed in the ≥85-year-old patient subgroup (common odds ratio, 4.20 [95% CI, 1.56-11.32]). Age ≥85 years was not significantly associated with differing rates of symptomatic intracerebral hemorrhage or reperfusion (adjusted odds ratio, 1.92 [95% CI, 0.71-5.15] and adjusted odds ratio, 0.91 [95% CI, 0.40-2.06], respectively).

CONCLUSIONS

Patients ≥85 years old with independent premorbid function more often achieve good functional outcomes and have lower rates of mortality when treated with EVT compared with conservative management, with an observed treatment effect modification of age on outcome. EVT should therefore not be withheld in this subgroup.

Correlation Between Computed Tomography-Based Tissue Net Water Uptake and Volumetric Measures of Cerebral Edema After Reperfusion Therapy

BACKGROUND

Cerebral edema after large hemispheric infarction is associated with poor functional outcome and mortality. Net water uptake (NWU) quantifies the degree of hypoattenuation on unenhanced-computed tomography (CT) and is increasingly used to measure cerebral edema in stroke research. Hemorrhagic transformation and parenchymal contrast staining after thrombectomy may confound NWU measurements. We investigated the correlation of NWU measured postthrombectomy with volumetric markers of cerebral edema and association with functional outcomes.

METHODS

In a pooled individual patient level analysis of patients presenting with anterior circulation large hemispheric infarction (core 80-300 mL or Alberta Stroke Program Early CT Score ≤5) in the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke trials) data set, cerebral edema was defined as the volumetric expansion of the ischemic hemisphere expressed as a ratio to the contralateral hemisphere(rHV). NWU and midline-shift were compared with rHV as the reference standard on 24-hour follow-up CT, adjusted for hemorrhagic transformation and the use of thrombectomy. Association between edema markers and day 90 functional outcomes (modified Rankin Scale) was assessed using ordinal logistic regression.

RESULTS

Overall (n=144), there was no correlation between NWU and rHV (r_s=0.055, P=0.51). In sub-group analyses, a weak correlation between NWU with rHV was observed after excluding patients with any degree of hemorrhagic transformation (r_s=0.211, P=0.015), which further improved after excluding thrombectomy patients (r_s=0.453, P=0.001). Midline-shift correlated strongly with rHV in all sub-group analyses (r_s>0.753, P=0.001). Functional outcome at 90 days was negatively associated with rHV (adjusted common odds ratio, 0.46 [95% CI, 0.32-0.65]; P<0.001) and midline-shift (adjusted common odds ratio, 0.85 [95% CI, 0.78-0.92]; P<0.001) but not NWU (adjusted common odds ratio, 1.00 [95% CI, 0.97-1.03]; P=0.84), adjusted for age, baseline National Institutes of Health Stroke Scale, and thrombectomy. Prognostic performance of NWU improved after excluding patients with hemorrhagic transformation and thrombectomy (adjusted odds ratio, 0.90 [95% CI, 0.80-1.02]; P=0.10).

CONCLUSIONS

NWU correlated poorly with conventional markers of cerebral edema and was not associated with clinical outcome in the presence of hemorrhagic transformation and thrombectomy. Measuring NWU postthrombectomy requires validation before implementation into clinical research. At present, the use of NWU should be limited to baseline CT, or follow-up CT only in patients without hemorrhagic transformation or treatment with thrombectomy.

Reduced Severity of Tissue Injury Within the Infarct May Partially Mediate the Benefit of Reperfusion in Ischemic Stroke

BACKGROUND

Emerging data suggest tissue within the infarct lesion is not homogenously damaged following ischemic stroke but has a gradient of injury. Using blood-brain-barrier (BBB) disruption as a marker of tissue injury, we tested whether therapeutic reperfusion improves clinical outcome by reducing the severity of tissue injury within the infarct in patients with ischemic stroke.

METHODS

In a pooled analysis of patients treated for anterior circulation large vessel occlusion in the EXTEND-IA TNK (Tenecteplase Versus Alteplase Before Endovascular Therapy for Ischemic Stroke) and EXTEND-IA part-2 (Determining the Optimal Dose of Tenecteplase Before Endovascular Therapy for Ischaemic Stroke) trials, post-treatment BBB permeability at 24 hours was calculated based on the extent of T1-brightening by extravascular gadolinium on T2* perfusion-weighted imaging and measured within the diffusion-weighted-imaging lesion. First, to determine the clinical significance of BBB disruption as a marker of severity of tissue injury, we examined the association between post-treatment BBB permeability and functional outcome. Second, we performed an exploratory (reperfusion, BBB permeability, functional outcome) mediation analysis to estimate the proportion of the reperfusion-outcome relationship that is mediated by change in BBB permeability.

RESULTS

In the 238 patients analyzed, an increased BBB permeability measured within the infarct at 24 hours was associated with a reduced likelihood of favorable outcome (90-day modified Rankin Scale score of ≤2) after adjusting for age, baseline National Institutes of Health Stroke Scale, premorbid modified Rankin Scale, infarct topography, laterality, thrombolytic agent, sex, parenchymal hematoma, and follow-up infarct volume (adjusted odds ratio, 0.86 [95% CI, 0.75-0.98], P=0.023). Mediation analysis suggested reducing the severity of tissue injury (as estimated by BBB permeability) accounts for 18.2% of the association between reperfusion and favorable outcome, as indicated by a reduction in the regression coefficient of reperfusion after addition of BBB permeability as a covariate.

CONCLUSIONS

In patients with ischemic stroke, reduced severity of tissue injury within the infarct, as determined by assessing the integrity of the BBB, is independently associated with improved functional outcome. In addition to reducing diffusion-weighted imaging-defined infarct volume, reperfusion may also improve clinical outcome by reducing tissue injury severity within the infarct.

Abstract 41: Functional Outcome Of Patients 85 Years Or Older With Acute Ischemic Stroke Following Endovascular Treatment - A Substudy Of The Hermes Meta-analysis

Introduction: Previous studies have reported poor outcomes and high rates of mortality following endovascular therapy (EVT) for ischemic stroke in older patients. However, patients ≥85 years were underrepresented in most randomized trials. Our aim was to study the influence of age on outcome and EVT effect for ischemic stroke in patients aged ≥85 years.

Methods: Data were from the HERMES collaboration, a meta-analysis of 7 randomized trials that tested the efficacy of EVT. Two multivariable ordinal logistic regression were used to compare the association between EVT and 90-day functional outcome (modified Rankin Scale, primary outcome) in patients ≥85 years old to those who were younger. Secondary outcomes included mortality at 90 days and symptomatic intracranial hemorrhage (sICH) at 24 hours.

Results: We included 1764 patients in the analysis, of whom 77 (4.4%) were ≥85 years old. While patients ≥85 years had worse outcomes (adjusted odds ratio [aOR] 0.26 (95%CI:0.14-0.48) and higher mortality rates (aOR:3.28, 95%CI:1.54-6.97) compared to those <85 years, a significant benefit of EVT was observed in the ≥85-year-old patient subgroup (common OR:4.20 (95%CI:1.56-11.32, Figure). Patients ≥85 years undergoing EVT had lower rates of mortality than those in the control group (31% vs. 54%, p<0.01). Age ≥85 years was not significantly associated with higher rates of sICH (adjusted cOR:2.3, 95%CI:0.59-8.93).

Conclusion: Patients ≥85 years old with independent premorbid function more often achieve good functional outcomes when treated with EVT compared to conservative management, with lower rates of mortality and no differences in sICH rates. EVT should therefore not be withheld in this subgroup.

Abstract 44: Safety Of Tenecteplase And Alteplase In Tandem Lesion Stroke: A Pooled Analysis Of The Extend-IA TNK Trials

Introduction: The efficacy of tenecteplase (TNK) in patients with tandem lesions (TL) in the anterior circulation is unknown. The longer half-life of TNK could potentially lead to increased hemorrhage, especially in patients who require stenting of the extracranial internal carotid artery (eICA) and subsequent antiplatelet therapy. We assessed the efficacy and safety of TNK in a pooled analysis of the EXTEND-IA TNK trials.

Methods: We compared the treatment effect of TNK (pooled analysis of 0.25 and 0.40mg/kg dosing) with alteplase (tPA), stratifying for TL presence. A TL was defined as a combination of eICA pathology (ipsilateral stenosis >70% or occlusion) and intracranial LVO. Outcomes evaluated include 90-day mRS, intracranial reperfusion at initial angiographic assessment, mortality, ICH (symptomatic [sICH] and parenchymal hematoma [PH]). Treatment effect was adjusted for baseline NIHSS, age, and time from symptom onset to puncture via mixed effects proportional odds and logistic regression models.

Results: Of 483 patients with an anterior circulation occlusion, 71/483 (15%) patients had a TL and 43/71 (61%) patients required eICA stenting. In TL patients, reperfusion at initial angiographic assessment was observed in 11/56 (20%) of patients treated with TNK vs. 1/15 (7%) patients treated with tPA (aOR:3.71; 95% CI:0.42-32.75). sICH was observed in 4/71(6%) TL vs 7/412 (2%) nonTL patients (p=0.04). Among TL patients, sICH occurred in 4/56 (7%) patients treated with TNK vs 0/15 (0%) tPA treated patients (p=0.57); sICH occurred in 2/40 (5%) of the 0.25mg/kg TNK group and 2/16 (12.5%) of the 0.40mg/kg TNK group. PH was observed in 6/56 (11%) patients treated with TNK vs 0/15 (0%) tPA treated patients (p=0.33). 90-day mRS (TNK median 2 vs. tPA median 4, acOR:1.21; 95% CI:0.42-3.48), mortality (TNK: 5 [9%] vs. tPA: 3 [20%], aOR:0.45; 95% CI:0.08-2.50), and eICA stenting (TNK: 35 [64%] vs. tPA: 8 [57%], p=0.65) rates did not differ between the two treatment groups.

Conclusions: Although patients with TL in the anterior circulation were at higher risk of hemorrhagic complications, these did not significantly differ between the TNK and tPA groups. A numeric increase in bleeding with TNK was not accompanied by an increase in mortality or worse functional outcome.

Abstract WMP89: Comparative Outcome Of Patients With And Without Mild Pre-Stroke Morbidity Following Endovascular Treatment - Results From The Hermes Meta-analysis

Introduction: Analyses of the effect of prestroke functional levels upon outcome of endovascular therapy (EVT) have focused on the course of patients with moderate to substantial prestroke disability. The effect of complete freedom from pre-existing disability (modified Rankin Scale [mRS]=0) vs. predominantly mild pre-existing disability (mRS≥1) has not been well delineated.

Methods: Data were from the HERMES collaboration, a meta-analysis of 7 randomized controlled trials that tested the safety and efficacy of EVT. Two multivariable ordinal logistic regression models were used to compare the association between EVT and 90-day mRS (primary outcome) in patients who were asymptomatic prestroke (mRS=0) and those who had predominantly mild disability prestroke (mRS≥1). Secondary outcomes included successful reperfusion (in the EVT subgroup) and symptomatic intracranial hemorrhage (sICH) at 24 hours.

Results: We included 1764 patients in the analysis, of whom 223 (12.6%) had a prestroke mRS≥1 (162 mRS 1, 61 mRS≥2). Patients with prestroke mRS≥1 had worse outcomes compared to those with prestroke mRS=0 (adjusted odds ratio [aOR] 0.42 (95%CI:0.28-0.63). Nonetheless, a significant benefit of EVT was observed in the mRS≥1 subgroup (common OR:1.79 (95%CI:1.11-2.89, Figure). No significant differences were observed with regards to rates of reperfusion (aOR:0.91, 95%CI:0.52-1.57) and sICH (aOR:1.03, 95%CI:0.37-2.93) between patients asymptomatic vs. predominantly with mild disability prestroke.

Conclusion: Patients completely asymptomatic prior to onset have better outcomes from EVT than those with mild disability. Patients with prestroke mRS=1 still do more often achieve good functional outcomes with EVT compared to conservative management, with similar rates of reperfusion and sICH. These findings indicate even mild pre-existing symptoms exert prognostic (outcome) but not predictive (different response to therapy) in patients eligible for EVT.

Abstract 36: Endovascular Thrombectomy Beyond 24 Hours From Last Known Well: A Pooled Multicenter International Cohort

Background: Limited data are available on endovascular thrombectomy (EVT) efficacy and safety in large vessel occlusion (LVO) patients presenting >24hr from last known well (LKW). We compared outcomes between patients receiving EVT and best medical management (MM) in a multicenter international cohort.

Methods: Consecutive patients with anterior circulation LVO presenting >24h after LKW from 13 centers from 7/2012-4/2021 were analyzed. Multivariable models for 90d mRS distribution and symptomatic ICH were adjusted for age, NIHSS, glucose, IV tPA, transfer status, clot location, time from LKW, CT ASPECTS and ischemic core (rCBF<30%) and Tmax >6s volumes.

Results: Of 240 patients with a median (IQR) LKW to presentation 28.3h (24.9-38.2), 153 (64%) received EVT. Baseline characteristics were similar except for NIHSS (EVT: 13 (8-20) vs MM: 17 (10-22), p=0.005), CT ASPECTS (EVT: 8(6-9) vs MM: 4(3-6), p<0.001) and ischemic core 2.5(0-13) vs 15(0-71) mL, p<0.001. EVT was associated with a better shift in 90d mRS (acOR: 2.45, 95% CI=1.42-4.22, p=0.001), higher functional independence (42% vs 10%, aOR: 4.84, 95% CI=2.02-11.64, p<0.001) and numerically lower mortality (22% vs 42%, aOR: 0.50, 95% CI=0.23-1.06, p=0.071), Fig 1A. However, EVT was associated with numerically higher sICH (5.5% vs 0%, p=0.10). Following EVT, 82% achieved successful reperfusion (mTICI 2b-3), which was associated with better shift in 90d mRS (acOR: 5.82, 95% CI: 1.77-19.10, p=0.004), higher functional independence (44% vs 22%, aOR: 5.03, 95% CI: 0.87-29.12, p=0.07) and lower mortality (20% vs 52%, aOR: 0.08, 95% CI: 0.01-0.57, p=0.01), Fig 1B.

Conclusions: EVT may be associated with better functional outcomes, despite numerically increased risk of sICH in patients presenting with anterior circulation LVO beyond 24 hours. Further prospective studies are warranted.

DIRECT-SAFE: A Randomized Controlled Trial of DIRECT Endovascular Clot Retrieval versus Standard Bridging Therapy

Background and Purpose

The benefit regarding co-treatment with intravenous (IV) thrombolysis before mechanical thrombectomy in acute ischemic stroke with large vessel occlusion remains unclear. To test the hypothesis that clinical outcome of ischemic stroke patients with intracranial internal carotid artery, middle cerebral artery or basilar artery occlusion treated with direct endovascular thrombectomy within 4.5 hours will be non-inferior compared with that of standard bridging IV thrombolysis followed by endovascular thrombectomy.

Methods

To randomize 780 patients 1:1 to direct thrombectomy or bridging IV thrombolysis with thrombectomy. An international-multicenter prospective randomized open label blinded endpoint trial (PROBE) (ClincalTrials.gov identifier: NCT03494920).

Results

Primary endpoint is functional independence defined as modified Rankin Scale (mRS) 0–2 or return to baseline at 90 days. Secondary end points include ordinal mRS analysis, good angiographic reperfusion (modified Thrombolysis in Cerebral Infarction score [mTICI] 2b–3), safety endpoints include symptomatic intracerebral hemorrhage and death.

Conclusions

DIRECT-SAFE will provide unique information regarding the impact of direct thrombectomy in patients with large vessel occlusion, including patients with basilar artery occlusion, with comparison across different ethnic groups.

Safety and Efficacy of Tenecteplase in Older Patients With Large Vessel Occlusion: A Pooled Analysis of the EXTEND-IA TNK Trials

BACKGROUND AND OBJECTIVES

Detailed study of tenecteplase (TNK) in patients greater than 80 years of age is limited. The objective of our study was to assess the safety and efficacy of TNK at 0.25 and 0.40 mg/kg doses in patients greater than 80 years with large vessel occlusion.

METHODS

A pooled analysis of the EXTEND-IA TNK randomized controlled trials (n=502). Patients were adults presenting with ischemic stroke due to occlusion of the intracranial internal carotid, middle cerebral, or basilar artery presenting within 4.5 hours of symptom onset. We compared the treatment effect of TNK 0.25mg/kg, TNK 0.40mg/kg, and alteplase 0.90mg/kg, stratifying for patient age (>80 years). Outcomes evaluated include 90-day modified Rankin scale (mRS), all-cause mortality, and symptomatic ICH. Treatment effect was adjusted for baseline NIHSS, age, and time from symptom onset to puncture via mixed effects proportional odds and logistic regression models.

RESULTS

In patients >80 years (n=137), TNK 0.25 mg/kg was associated with improved 90-day mRS (median 3 vs. 4, adjusted common OR=2.70, 95% CI: 1.23-5.94) and reduced mortality (aOR=0.34, 95% CI: 0.13-0.91) versus 0.40 mg/kg. TNK 0.25 mg/kg was associated with improved 90-day mRS (median 3 vs. 4, acOR=2.28, 95% CI: 1.03-5.05) versus alteplase. No difference in 90-day mRS or mortality was detected between alteplase and TNK 0.40 mg/kg. Symptomatic ICH was observed in 4 patients treated with TNK 0.40 mg/kg, one patient treated with alteplase and zero patients treated with TNK 0.25 mg/kg. In patients ≤ 80 years, no differences in 90-day mRS, mortality, or symptomatic ICH was observed between TNK 0.25 mg/kg, alteplase, and TNK 0.40 mg/kg.

CONCLUSIONS

TNK 0.25 mg/kg was associated with improved 90-day mRS and lower mortality in patients greater than 80 years of age. No differences between the doses were observed in younger patients.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that tenecteplase 0.25 mg/kg given before endovascular therapy in patients >80 years old with large vessel occlusion stroke is associated with better functional outcomes at 90 days and reduced mortality when compared to tenecteplase 0.40 mg/kg or alteplase 0.90 mg/kg.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT02388061, NCT03340493 https://www.clinicaltrials.gov/ct2/show/NCT02388061 https://www.clinicaltrials.gov/ct2/show/NCT03340493.

Microvascular Dysfunction in Blood-Brain Barrier Disruption and Hypoperfusion Within the Infarct Posttreatment Are Associated With Cerebral Edema

BACKGROUND AND PURPOSE

Factors contributing to cerebral edema in the post-hyperacute period of ischemic stroke (first 24-72 hours) are poorly understood. Blood-brain barrier (BBB) disruption and postischemic hyperperfusion reflect microvascular dysfunction and are associated with hemorrhagic transformation. We investigated the relationships between BBB integrity, cerebral blood flow, and space-occupying cerebral edema in patients who received acute reperfusion therapy.

METHODS

We performed a pooled analysis of patients treated for anterior circulation large vessel occlusion in the EXTEND-IA TNK and EXTEND-IA TNK part 2 trials who had MRI with dynamic susceptibility contrast-enhanced perfusion-weighted imaging 24 hours after treatment. We investigated the associations between BBB disruption and cerebral blood flow within the infarct with cerebral edema assessed using 2 metrics: first midline shift (MLS) trichotomized as an ordinal scale of negligible (<1 mm), mild (≥1 to <5 mm), or severe (≥5 mm), and second relative hemispheric volume (rHV), defined as the ratio of the 3-dimensional volume of the ischemic hemisphere relative to the contralateral hemisphere.

RESULTS

Of 238 patients analyzed, 133 (55.9%) had negligible, 93 (39.1%) mild, and 12 (5.0%) severe MLS at 24 hours. The associated median rHV was 1.01 (IQR, 1.00-1.028), 1.03 (IQR, 1.01-1.077), and 1.15 (IQR, 1.08-1.22), respectively. MLS and rHV were associated with poor functional outcome at 90 days (P<0.002). Increased BBB permeability was independently associated with more edema after adjusting for age, occlusion location, reperfusion, parenchymal hematoma, and thrombolytic agent used (MLS cOR, 1.12 [95% CI, 1.03-1.20], P=0.005; rHV β, 0.39 [95% CI, 0.24-0.55], P<0.0001), as was reduced cerebral blood flow (MLS cOR, 0.25 [95% CI, 0.10-0.58], P=0.001; rHV β, -2.95 [95% CI, -4.61 to -11.29], P=0.0006). In subgroup analysis of patients with successful reperfusion (extended Treatment in Cerebral Ischemia 2b-3, n=200), reduced cerebral blood flow remained significantly associated with edema (MLS cOR, 0.37 [95% CI, 0.14-0.98], P=0.045; rHV β, -2.59 [95% CI, -4.32 to -0.86], P=0.004).

CONCLUSIONS

BBB disruption and persistent hypoperfusion in the infarct after reperfusion treatment is associated with space-occupying cerebral edema. Further studies evaluating microvascular dysfunction during the post-hyperacute period as biomarkers of poststroke edema and potential therapeutic targets are warranted.

Posterior National Institutes of Health Stroke Scale Improves Prognostic Accuracy in Posterior Circulation Stroke

BACKGROUND AND PURPOSE

The National Institutes of Health Stroke Scale (NIHSS) underestimates clinical severity in posterior circulation stroke and patients presenting with low NIHSS may be considered ineligible for reperfusion therapies. This study aimed to develop a modified version of the NIHSS, the Posterior NIHSS (POST-NIHSS), to improve NIHSS prognostic accuracy for posterior circulation stroke patients with mild-moderate symptoms.

METHODS

Clinical data of consecutive posterior circulation stroke patients with mild-moderate symptoms (NIHSS <10), who were conservatively managed, were retrospectively analyzed from the Basilar Artery Treatment and Management registry. Clinical features were assessed within 24 hours of symptom onset; dysphagia was assessed by a speech therapist within 48 hours of symptom onset. Random forest classification algorithm and constrained optimization were used to develop the POST-NIHSS in the derivation cohort. The POST-NIHSS was then validated in a prospective cohort. Poor outcome was defined as modified Rankin Scale score ≥3 at 3 months.

RESULTS

We included 202 patients (mean [SD] age 63 [14] years, median NIHSS 3 [interquartile range, 1-5]) in the derivation cohort and 65 patients (mean [SD] age 63 [16] years, median NIHSS 2 [interquartile range, 1-4]) in the validation cohort. In the derivation cohort, age, NIHSS, abnormal cough, dysphagia and gait/truncal ataxia were ranked as the most important predictors of functional outcome. POST-NIHSS was calculated by adding 5 points for abnormal cough, 4 points for dysphagia, and 3 points for gait/truncal ataxia to the baseline NIHSS. In receiver operating characteristic analysis adjusted for age, POST-NIHSS area under receiver operating characteristic curve was 0.80 (95% CI, 0.73-0.87) versus NIHSS area under receiver operating characteristic curve, 0.73 (95% CI, 0.64-0.83), P=0.03. In the validation cohort, POST-NIHSS area under receiver operating characteristic curve was 0.82 (95% CI, 0.69-0.94) versus NIHSS area under receiver operating characteristic curve 0.73 (95% CI, 0.58-0.87), P=0.04.

CONCLUSIONS

POST-NIHSS showed higher prognostic accuracy than NIHSS and may be useful to identify posterior circulation stroke patients with NIHSS <10 at higher risk of poor outcome.

Tranexamic acid for intracerebral haemorrhage within 2 hours of onset: protocol of a phase II randomised placebo-controlled double-blind multicentre trial

Rationale

Haematoma growth is common early after intracerebral haemorrhage (ICH), and is a key determinant of outcome. Tranexamic acid, a widely available antifibrinolytic agent with an excellent safety profile, may reduce haematoma growth.

Methods and design

Stopping intracerebral haemorrhage with tranexamic acid for hyperacute onset presentation including mobile stroke units (STOP-MSU) is a phase II double-blind, randomised, placebo-controlled, multicentre, international investigator-led clinical trial, conducted within the estimand statistical framework.

Hypothesis

In patients with spontaneous ICH, treatment with tranexamic acid within 2 hours of onset will reduce haematoma expansion compared with placebo.

Sample size estimates

A sample size of 180 patients (90 in each arm) would be required to detect an absolute difference in the primary outcome of 20% (placebo 39% vs treatment 19%) under a two-tailed significance level of 0.05. An adaptive sample size re-estimation based on the outcomes of 144 patients will allow a possible increase to a prespecified maximum of 326 patients.

Intervention

Participants will receive 1 g intravenous tranexamic acid over 10 min, followed by 1 g intravenous tranexamic acid over 8 hours; or matching placebo.

Primary efficacy measure

The primary efficacy measure is the proportion of patients with haematoma growth by 24±6 hours, defined as either ≥33% relative increase or ≥6 mL absolute increase in haematoma volume between baseline and follow-up CT scan.

Discussion

We describe the rationale and protocol of STOP-MSU, a phase II trial of tranexamic acid in patients with ICH within 2 hours from onset, based in participating mobile stroke units and emergency departments.

Cerebral Large Vessel Occlusion Caused by Fat Embolism-A Case Series and Review of the Literature

The diagnosis of fat embolism syndrome typically involves neurological, respiratory and dermatological manifestations of microvascular occlusion 24–72 h after a precipitating event. However, fat embolism causing cerebral large vessel occlusion strokes and their sequelae have rarely been reported in the literature. This case series reports three patients with fat emboli post operatively causing cerebral large vessel occlusions, as well as a review of the literature to identify differences in clinical presentations and outcomes in stroke secondary to fat emboli causing large vessel occlusions compared to those with fat embolism syndrome.

Association between pre-treatment perfusion profile and cerebral edema after reperfusion therapies in ischemic stroke

The relationship between reperfusion and edema is unclear, with experimental and clinical data yielding conflicting results. We investigated whether the extent of salvageable and irreversibly-injured tissue at baseline influenced the effect of therapeutic reperfusion on cerebral edema. In a pooled analysis of 415 patients with anterior circulation large vessel occlusion from the Tenecteplase-versus-Alteplase-before-Endovascular-Therapy-for-Ischemic-Stroke (EXTEND-IA TNK) part 1 and 2 trials, associations between core and mismatch volume on pre-treatment CT-Perfusion with cerebral edema at 24-hours, and their interactions with reperfusion were tested. Core volume was associated with increased edema (p < 0.001) with no significant interaction with reperfusion (p = 0.82). In comparison, a significant interaction between reperfusion and mismatch volume (p = 0.03) was observed: Mismatch volume was associated with increased edema in the absence of reperfusion (p = 0.009) but not with reperfusion (p = 0.27). When mismatch volume was dichotomized at the median (102 ml), reperfusion was associated with reduced edema in patients with large mismatch volume (p < 0.001) but not with smaller mismatch volume (p = 0.35). The effect of reperfusion on edema may be variable and dependent on the physiological state of the cerebral tissue. In patients with small to moderate ischemic core volume, the benefit of reperfusion in reducing edema is related to penumbral salvage.

Automated Final Lesion Segmentation in Posterior Circulation Acute Ischemic Stroke Using Deep Learning

Final lesion volume (FLV) is a surrogate outcome measure in anterior circulation stroke (ACS). In posterior circulation stroke (PCS), this relation is plausibly understudied due to a lack of methods that automatically quantify FLV. The applicability of deep learning approaches to PCS is limited due to its lower incidence compared to ACS. We evaluated strategies to develop a convolutional neural network (CNN) for PCS lesion segmentation by using image data from both ACS and PCS patients. We included follow-up non-contrast computed tomography scans of 1018 patients with ACS and 107 patients with PCS. To assess whether an ACS lesion segmentation generalizes to PCS, a CNN was trained on ACS data (ACS-CNN). Second, to evaluate the performance of only including PCS patients, a CNN was trained on PCS data. Third, to evaluate the performance when combining the datasets, a CNN was trained on both datasets. Finally, to evaluate the performance of transfer learning, the ACS-CNN was fine-tuned using PCS patients. The transfer learning strategy outperformed the other strategies in volume agreement with an intra-class correlation of 0.88 (95% CI: 0.83-0.92) vs. 0.55 to 0.83 and a lesion detection rate of 87% vs. 41-77 for the other strategies. Hence, transfer learning improved the FLV quantification and detection rate of PCS lesions compared to the other strategies.