Thrombus Migration Paradox in Patients With Acute Ischemic Stroke

A hyper-viscoelastic uniaxial characterization of collagenous embolus analogs in acute ischemic stroke

PURPOSE

Acute ischemic stroke is a leading cause of death and morbidity worldwide. Despite advances in medical technology, nearly 30% of strokes result in incomplete vessel recanalization. Recent studies have demonstrated that clot composition correlates with success rates of mechanical thrombectomy procedures. To understand clot behavior during thrombectomy, which exerts considerable strains on thrombi, in vitro studies must characterize the rate-dependent high-strain behavior of embolus analogs (EAs) with different formation conditions, which can be used to fit models of hyper-viscoelasticity.

METHODS

In this study, the effect of collagen infiltration as a carotid-induced collagen-rich thrombosis surrogate is considered as a contributor to embolus analog high-strain stiffness, when compared to 40% hematocrit EAs.

RESULTS

EA high-strain stiffnesses, characterized on a uniaxial load frame, increase by an order of magnitude for collagenous clot analogs. Chandler loop analogs show high-strain stiffnesses and clot compositions commensurate with previous reports of stroke patient clots, and collagenous clots show significant increase in stiffness when compared to stroke patient clots. Finally, hyper-viscoelastic curve fitting demonstrates the asymmetry between tension and compression. Nonlinear, rate-dependent models that consider clot-stiffening behavior match the high strain stiffness of clots fairly well. Furthermore, we demonstrate that the stability of the elastic energy needs to be considered to obtain optimal curve fits for high-strain, rate dependent data.

CONCLUSION

This study provides a framework for the development of dynamically formed EAs that mimic the mechanical and structural properties of in vivo clots and provides parameters for numerical simulation of clot behavior with hyper-viscoelastic models.

Preoperative and intraoperative tirofiban during endovascular thrombectomy in large vessel occlusion stroke due to large artery atherosclerosis

BACKGROUND AND PURPOSE

The aim of this study is to investigate the efficacy and safety of preoperative versus intraoperative tirofiban in patients with large vessel occlusion (LVO) due to large artery atherosclerosis (LAA).

METHODS

This is a retrospective multicenter cohort study based on the RESCUE-RE (Registration Study for Critical Care of Acute Ischemic Stroke After Recanalization) trial enrolling patients with anterior circulation LVO classified as LAA within 24 h of onset. Patients were divided into three groups: preoperative tirofiban (PT), intraoperative tirofiban (IT), and no tirofiban (NT). Propensity score matching (PSM) was used to balance baseline characteristics. The efficacy outcomes included 90-day functional independence (modified Rankin Scale score = 0-2) and early partial recanalization (EPR; defined as a modified Thrombolysis in Cerebral Infarction score = 1-2a). The safety outcomes included symptomatic intracranial hemorrhage (sICH).

RESULTS

A total of 104 matched triplets were obtained through PSM. Compared with NT, PT increased 90-day functional independence (60.8% vs. 42.3%, p = 0.008) and EPR (42.7% vs. 18.3%, p < 0.001) rate, with a tendency to increase the asymptomatic intracranial hemorrhage (aICH) proportion (28.8% vs. 18.3%, p = 0.072). Compared with IT, PT had a higher 90-day functional independence (60.8% vs. 45.2%, p = 0.025) and EPR (42.7% vs. 20.2%, p = 0.001) rate, with no significant difference in sICH (14.4% vs. 7.7%, p = 0.122) and aICH (28.8% vs. 21.2%, p = 0.200). Compared with NT, IT had a lower 90-day mortality rate (9.6% vs. 24.0%, p = 0.005).

CONCLUSIONS

Tirofiban shows good adjuvant therapy potential in acute ischemic stroke-LVO due to LAA patients. PT is associated with higher rates of EPR and better therapeutic efficacy. In addition, EPR may be a potential way to improve prognosis.

Risk of Hemorrhagic Transformation after Mechanical Thrombectomy without versus with IV Thrombolysis for Acute Ischemic Stroke: A Systematic Review and Meta-analysis of Randomized Clinical Trials

BACKGROUND

When treating acute ischemic stroke due to large-vessel occlusion, both mechanical thrombectomy and intravenous (IV) thrombolysis carry the risk of intracerebral hemorrhage.

PURPOSE

This study aimed to delve deeper into the risk of intracerebral hemorrhage and its subtypes associated with mechanical thrombectomy with or without IV thrombolysis to contribute to better decision-making in the treatment of acute ischemic stroke due to large-vessel occlusion.

DATA SOURCES

PubMed, EMBASE, and Scopus databases were searched for relevant studies from inception to September 6, 2023.

STUDY SELECTION

The eligibility criteria included randomized clinical trials or post hoc analysis of randomized controlled trials that focused on patients with acute ischemic stroke in the anterior circulation. After screening 4870 retrieved records, we included 9 studies (6 randomized controlled trials and 3 post hoc analyses of randomized controlled trials) with 3241 patients.

DATA ANALYSIS

The interventions compared were mechanical thrombectomy + IV thrombolysis versus mechanical thrombectomy alone, with the outcome of interest being any form of intracerebral hemorrhage and symptomatic intracerebral hemorrhage after intervention. A common definition for symptomatic intracerebral hemorrhage was pooled from various classification systems, and subgroup analyses were performed on the basis of different definitions and anatomic descriptions of hemorrhage. The quality of the studies was assessed using the revised version of Cochrane Risk of Bias 2 assessment tool. Meta-analysis was performed using the random effects model.

DATA SYNTHESIS

Eight studies had some concerns, and 1 study was considered high risk. Overall, the risk of symptomatic intracerebral hemorrhage was comparable between mechanical thrombectomy + IV thrombolysis and mechanical thrombectomy alone (risk ratio, 1.24 [95% CI, 0.89-1.72]; P = .20), with no heterogeneity across studies. Subgroup analysis of symptomatic intracerebral hemorrhage showed a non-significant difference between 2 groups based on the National Institute of Neurological Disorders and Stroke (P = .3), the Heidelberg Bleeding Classification (P = .5), the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (P = .4), and the European Cooperative Acute Stroke Study III (P = .7) criteria. Subgroup analysis of different anatomic descriptions of intracerebral hemorrhage showed no difference between the 2 groups. Also, we found no difference in the risk of any intracerebral hemorrhage between two groups (risk ratio, 1.10 [95% CI, 1.00-1.21]; P = .052) with no heterogeneity across studies.

LIMITATIONS

There was a potential for performance bias in most studies.

CONCLUSIONS

In this systematic review and meta-analysis, the risk of any intracerebral hemorrhage and symptomatic intracerebral hemorrhage, including its various classifications and anatomic descriptions, was comparable between mechanical thrombectomy + IV thrombolysis and mechanical thrombectomy alone.

Clot migration in patients treated with tenecteplase versus alteplase before mechanical thrombectomy

INTRODUCTION

This study aimed to describe and analyze the rate of clot migration of vessel thrombosis to distal segments in patients with acute ischemic stroke (AIS) who received intravenous thrombolysis (IVT) with tenecteplase (TNK) and alteplase (ALT) before mechanical thrombectomy (MT). In addition, we aimed to determine the relationship between thrombus migration and functional prognosis.

METHODS

This study followed the STROBE reporting guidelines. We performed a retrospective analysis of a series of patients from November 2017 to April 2023 with an AIS with thrombosis on CT imaging, treated with IVT (TNK or ALT, split into two distinct groups) prior to mechanical thrombectomy.

RESULTS

Two hundred and fifty-six patients with large vessel occlusion (LVO) were included. Ninety-six had received TNK. One hundred and sixty had received ALT. Of the 96 TNK patients, 25 experienced either complete recanalization (n = 3) or thrombus migration (n = 22). Of the 160 ALT patients, 20 experienced either complete recanalization (n = 6) or thrombus migration (n = 14). The difference being statistically substantial for the thrombus migration rate (OR = 3.61, 95% confidence interval: 1.63; 7.98). Migration to an irretrievable very distal segment occurred in four (4%) patients with TNK and in three patients (2%) with ALT (p > 0.05). Thrombus migration was not significantly associated to a different functional prognosis, measured through Rankin scale after 3 months (OR = 0.44, 95% confidence interval: 0.17; 1.12).

CONCLUSION

The use of TNK over ALT as a fibrinolytic agent is associated with a higher thrombus migration rate. The migration of thrombi to distal segments, which are theoretically less accessible for mechanical thrombectomy, did not result in worse clinical outcomes.

MRI-based microthrombi detection in stroke with polydopamine iron oxide

In acute ischemic stroke, even when successful recanalization is obtained, downstream microcirculation may still be obstructed by microvascular thrombosis, which is associated with compromised brain reperfusion and cognitive decline. Identifying these microthrombi through non-invasive methods remains challenging. We developed the PHySIOMIC (Polydopamine Hybridized Self-assembled Iron Oxide Mussel Inspired Clusters), a MRI-based contrast agent that unmasks these microthrombi. In a mouse model of thromboembolic ischemic stroke, our findings demonstrate that the PHySIOMIC generate a distinct hypointense signal on T2*-weighted MRI in the presence of microthrombi, that correlates with the lesion areas observed 24 hours post-stroke. Our microfluidic studies reveal the role of fibrinogen in the protein corona for the thrombosis targeting properties. Finally, we observe the biodegradation and biocompatibility of these particles. This work demonstrates that the PHySIOMIC particles offer an innovative and valuable tool for non-invasive in vivo diagnosis and monitoring of microthrombi, using MRI during ischemic stroke.

Recanalization status and temporal evolution of early ischemic changes following stroke thrombectomy

INTRODUCTION

Present-day computer tomography (CT) scanners have excellent spatial resolution and signal-to-noise ratio and are instrumental detecting early ischemic changes (EIC) in brain. We assessed the temporal changes of EIC based on the recanalization status after thrombectomy.

PATIENTS AND METHODS

The cohort comprises consecutive patients with acute ischemic stroke in anterior circulation treated with thrombectomy in tertiary referral hospital. All baseline and follow-up scans were screened for any ischemic changes and further classified using Alberta Stroke Program Early CT Score (ASPECTS). Generalized linear mixed models were used to analyze the impact of recanalization status using modified Thrombolysis in Cerebral Infarction (mTICI) on temporal evolution of ischemic changes.

RESULTS

We included 614 patients with ICA, M1, or M2 occlusions. Median ASPECTS score was 9 (IQR 7-10) at baseline and 7 (5-8) at approximately 24 h. mTICI 3 was achieved in 207 (33.8%), 2B 241 (39.3%), 2A in 77 (12.6%), and 0-1 in 88 (14.3%) patients. Compared to patients with mTICI 3, those with mTICI 0-1 and 2A had less favorable temporal changes of ASPECTS (p < 0.001). Effect of recanalization was noted in the cortical regions of ICA/M1 patients, but not in their deep structures or patients with M2 occlusions. All ischemic changes detected at baseline were also present at all follow-up images, regardless of the recanalization status.

CONCLUSIONS

Temporal evolution of the ischemic changes and ASPECTS are related to the success of the recanalization therapy in cortical regions of ICA/M1 patients, but not in their deep brain structures or M2 patients. In none of the patients did EIC revert in any brain region after successful recanalization.

Arterial Recanalization During Interhospital Transfer for Thrombectomy

BACKGROUND

Patients with acute ischemic stroke harboring a large vessel occlusion admitted to nonendovascular-capable centers often require interhospital transfer for thrombectomy. We evaluated the incidence and predictors of arterial recanalization during transfer, as well as the relationship between interhospital recanalization and clinical outcomes.

METHODS

We analyzed data from 2 cohorts of patients with an anterior circulation large vessel occlusion transferred for consideration of thrombectomy to a comprehensive center, with arterial imaging at the referring hospital and on comprehensive stroke center arrival. Interhospital recanalization was determined by comparison of the baseline and posttransfer arterial imaging and was defined as revised arterial occlusive lesion (rAOL) score 2b to 3. Pretransfer variables independently associated with interhospital recanalization were studied using multivariable logistic regression analysis.

RESULTS

Of the 520 included patients (Montpellier, France, n=237; Stanford, United States, n=283), 111 (21%) experienced interhospital recanalization (partial [rAOL=2b] in 77% and complete [rAOL=3] in 23%). Pretransfer variables independently associated with recanalization were intravenous thrombolysis (adjusted odds ratio, 6.8 [95% CI, 4.0-11.6]), more distal occlusions (intracranial carotid occlusion as reference: adjusted odds ratio, 2.0 [95% CI, 0.9-4.5] for proximal first segment of the middle cerebral artery, 5.1 [95% CI, 2.3-11.5] for distal first segment of the middle cerebral artery, and 5.0 [95% CI, 2.1-11.8] for second segment of the middle cerebral artery), and smaller clot burden (clot burden score 0-4 as reference: adjusted odds ratio, 3.4 [95% CI, 1.5-7.6] for 5-7 and 5.6 [95% CI, 2.4-12.7] for 8-9). Recanalization on arrival at the comprehensive center was associated with less interhospital infarct growth (rAOL, 0-2a: 11.6 mL; rAOL, 2b: 2.2 mL; rAOL, 3: 0.6 mL; Ptrend<0.001) and greater interhospital National Institutes of Health Stroke Scale score improvement (0 versus -5 versus -6; Ptrend<0.001). Interhospital recanalization was associated with reduced 3-month disability (adjusted common odds ratio, 2.51 [95% CI, 1.68-3.77]) with greater benefit from complete than partial recanalization.

CONCLUSIONS

Recanalization is frequently observed during interhospital transfer for thrombectomy and is strongly associated with favorable outcomes, even when partial. Broadening thrombolysis indications in primary centers, and developing therapies that increase recanalization during transfer, will likely improve clinical outcomes.

A deep learning method to identify and localize large-vessel occlusions from cerebral digital subtraction angiography

BACKGROUND AND PURPOSE

An essential step during endovascular thrombectomy is identifying the occluded arterial vessel on a cerebral digital subtraction angiogram (DSA). We developed an algorithm that can detect and localize the position of occlusions in cerebral DSA.

METHODS

We retrospectively collected cerebral DSAs from a single institution between 2018 and 2020 from 188 patients, 86 of whom suffered occlusions of the M1 and proximal M2 segments. We trained an ensemble of deep-learning models on fewer than 60 large-vessel occlusion (LVO)-positive patients. We evaluated the model on an independent test set and evaluated the truth of its predicted localizations using Intersection over Union and expert review.

RESULTS

On an independent test set of 166 cerebral DSA frames with an LVO prevalence of 0.19, the model achieved a specificity of 0.95 (95% confidence interval [CI]: 0.90, 0.99), a precision of 0.7450 (95% CI: 0.64, 0.88), and a sensitivity of 0.76 (95% CI: 0.66, 0.91). The model correctly localized the LVO in at least one frame in 13 of the 14 LVO-positive patients in the test set. The model achieved a precision of 0.67 (95% CI: 0.52, 0.79), recall of 0.69 (95% CI: 0.46, 0.81), and a mean average precision of 0.75 (95% CI: 0.56, 0.91).

CONCLUSION

This work demonstrates that a deep learning strategy using a limited dataset can generate effective representations used to identify LVOs. Generating an expanded and more complete dataset of LVOs with obstructed LVOs is likely the best way to improve the model's ability to localize LVOs.

Thrombus migration in patients with acute ischaemic stroke undergoing endovascular thrombectomy

OBJECTIVE

The impact of thrombus migration (TM) prior to endovascular thrombectomy (EVT) on clinical outcomes and revascularisation rates remains unknown. We aimed to examine whether preinterventional TM modifies the treatment effects of direct EVT versus bridging EVT in acute large vessel occlusion patients.

METHODS

All patients undergoing catheter angiography in the Direct Intra-arterial thrombectomy in order to Revascularise acute ischaemic stroke patients with large vessel occlusion Efficiently in Chinese Tertiary hospitals: A Multicentre randomised clinical Trial were included. TM was determined by radiologists unaware of the study by analysing discrepancies between computed tomographic angiography at baseline and first-run digital subtraction angiography before EVT. The primary outcome was the score on the modified Rankin scale (mRS) assessed at 90 days.

RESULTS

Of 627 included patients, the TM rate was 11.3% (71/627). In the multivariable logistic regression model, baseline National Institutes of Health Stroke Scale score (adjusted OR 0.956, 95% CI 0.916 to 0.999; p=0.043) and intravenous thrombolysis (adjusted OR 2.614, 95% CI 1.514 to 4.514; p<0.001) were independently associated with TM. The patients with TM were less likely to be completely recanalised than those without TM (21.27% vs 36.23%, p=0.040). The interaction of TM and the EVT treatment effect did not significantly affect mRS shift analysis (p=0.687) or mRS scores of 0 to 1 (p=0.436).

CONCLUSION

Preinterventional TM does not modify the treatment effects of direct versus bridging EVT on functional outcomes in patients with acute ischaemic stroke with anterior large vessel occlusion. TM leads to a lower complete recanalisation rate.

TRIAL REGISTRATION NUMBER

Intravenous Thrombolysis Before Thrombectomy Improves Functional Outcome After Stroke Independent of Reperfusion Grade

BACKGROUND

We studied the association of bridging intravenous thrombolysis (IVT) before thrombectomy for anterior circulation large-vessel occlusion and functional outcome and scrutinized its dependence on grade of reperfusion and distal thrombus migration.

METHODS AND RESULTS

We included consecutive patients with anterior circulation large-vessel occlusion from our prospective registry of thrombectomy-eligible patients treated from January 1, 2017 to January 1, 2023 at a tertiary stroke center in Germany in this retrospective cohort study. To evaluate the association of bridging IVT and functional outcome quantified via modified Rankin Scale score at 90 days we used multivariable logistic and lasso regression including interaction terms with grade of reperfusion quantified via modified Thrombolysis in Cerebral Infarction (mTICI) scale and distal thrombus migration adjusted for demographic and cardiovascular risk profiles, clinical and imaging stroke characteristics, onset-to-recanalization time and distal thrombus migration. We performed sensitivity analysis using propensity score matching. In our study population of 1000 thrombectomy-eligible patients (513 women; median age, 77 years [interquartile range, 67-84]), IVT emerged as a predictor of favorable functional outcome (modified Rankin Scale score, 0-2) independent of modified mTICI score (adjusted odds ratio, 0.49 [95% CI, 0.32-0.75]; P=0.001). In those who underwent thrombectomy (n=812), the association of IVT and favorable functional outcome was reproduced (adjusted odds ratio, 0.49 [95% CI, 0.31-0.74]; P=0.001) and was further confirmed on propensity score analysis, where IVT led to a 0.35-point decrease in 90-day modified Rankin Scale score (ß=-0.35 [95 CI%, -0.68 to 0.01]; P=0.04). The additive benefit of IVT remained independent of modified mTICI score (ß=-1.79 [95% CI, -3.43 to -0.15]; P=0.03) and distal thrombus migration (ß=-0.41 [95% CI, -0.69 to -0.13]; P=0.004) on interaction analysis. Consequently, IVT showed an additive association with functional outcome in the subpopulation of patients undergoing thrombectomy who achieved successful reperfusion (mTICI ≥2b; ß=-0.46 [95% CI, -0.74 to -0.17]; P=0.002) and remained beneficial in those with unsuccessful reperfusion (mTICI ≤2a; ß=-0.47 [95% CI, -0.96 to 0.01]; P=0.05).

CONCLUSIONS

In thrombectomy-eligible patients with anterior circulation large-vessel occlusion, IVT improves functional outcome independent of grade of reperfusion and distal thrombus migration.

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.

Effect of Bridging Thrombolysis on the Efficacy of Stent Retriever Thrombectomy Techniques : Insights from the SWIFT-DIRECT trial

BACKGROUND

There are little available data regarding the influence of intravenous thrombolysis (IVT) on the efficacy of different first line endovascular treatment (EVT) techniques.

METHODS

We used the dataset of the SWIFT-DIRECT trial which randomized 408 patients to IVT + EVT or EVT alone at 48 international sites. The protocol required the use of a stent retriever (SR), but concomitant use of a balloon guide catheter (BGC) and/or distal aspiration (DA) catheter was left to the discretion of the operators. Four first line techniques were applied in the study population: SR, SR + BGC, SR + DA, SR + DA + BGC. To assess whether the effect of allocation to IVT + EVT versus EVT alone was modified by the first line technique, interaction models were fitted for predefined outcomes. The primary outcome was first pass mTICI 2c‑3 reperfusion (FPR).

RESULTS

This study included 385 patients of whom 172 were treated with SR + DA, 121 with SR + DA + BGC, 57 with SR + BGC and 35 with SR. There was no evidence that the effect of IVT + EVT versus EVT alone would be modified by the choice of first line technique; however, allocation to IVT + EVT increased the odds of FPR by a factor of 1.68 (95% confidence interval, CI 1.11-2.54).

CONCLUSION

This post hoc analysis does not suggest treatment effect heterogeneity of IVT + EVT vs EVT alone in different stent retriever techniques but provides evidence for increased FPR if bridging IVT is administered before stent retriever thrombectomy.

Thrombus migration in emergent M1 middle cerebral artery occlusion

BACKGROUND AND PURPOSE

Thrombus migration (TM) is a well-established phenomenon in patients with intracranial vessel occlusion, particularly in those who receive alteplase. However, the relationship between TM, reperfusion success, and clinic-radiological outcomes is still being determined. This study aimed to describe the various outcomes in the event of TM in patients with M1 middle cerebral artery (M1 MCA) occlusion.

MATERIALS AND METHODS

The study involved a retrospective analysis of patients undergoing endovascular thrombectomy (EVT) due to M1 MCA occlusion from two tertiary centers between January 2015 and December 2020. The proximal positions of thrombi were measured using a curve tool on CT or MR angiography before EVT. Subsequently, measurements were taken on angiographic imaging. Patients were grouped based on the amount of difference between the two measurements: growth (≤ - 10 mm), stability (> -10 mm and ≤ 10 mm), migration (> 10 mm), and resolution.

RESULTS

A total of 463 patients (266 [57%] females, median 76 [interquartile range IQR: 65-83] years) were analyzed. Of them, 106 (22.8%) expressed any degree of TM. In multivariate ordinal regression analysis, the alteplase was significantly associated with TM (t = 2.192, p = 0.028), as was the greater interval from first imaging to angiography (t = 2.574, p = 0.010). In multivariate logistical regression analysis, the good clinical outcome measured by the modified Rankin scale (0-2) was not associated with TM status.

CONCLUSIONS

Thrombus migration within the M1 MCA segment occurs in almost a quarter of patients, is associated with alteplase administration, and is mainly irrelevant to radiological and clinical outcome.

Endovascular Thrombectomy With or Without Thrombolysis for Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

To this date, whether to administer intravenous thrombolysis (IVT) prior to endovascular thrombectomy (EVT) for stroke patients still stirs some debate. We aimed to systematically update the evidence from randomized trials comparing EVT alone vs EVT with bridging IVT.

Methods

We searched MEDLINE, EMBASE, and the Cochrane Library to identify randomized controlled trials (RCTs) comparing EVT with or without IVT in patients presenting with stroke secondary to a large vessel occlusion. We conducted meta-analyses using random-effects models to compare functional independence, mortality, and symptomatic intracranial hemorrhage (sICH), between EVT and EVT with IVT. We assessed risk of bias using the Cochrane risk-of-bias tool and certainty of evidence for each outcome using the GRADE approach.

Results

Of 11,111 citations, we included 6 studies with a total of 2336 participants. We found low-certainty evidence of possibly a small decrease in the proportion of patients with functional independence (risk difference [RD] -2.0%, 95% CI -5.9% to 2.0%), low-certainty evidence that there is possibly a small increase in mortality (RD 1.0%, 95% CI -2.2% to 4.7%), and moderate-certainty evidence that there is probably a decrease in sICH (RD -1.0%, 95% CI -1.6% to .7%) for patients with EVT alone compared to EVT plus IVT, respectively.

Conclusion

Low-certainty evidence shows that there is possibly a small decrease in functional independence, low-certainty evidence shows that there is possibly a small increase in mortality, and moderate-certainty evidence that there is probably a decrease in sICH for patients with EVT alone compared to EVT plus IVT.

Thrombus migration in ischemic stroke due to large vessel occlusion: a question of time

BACKGROUND

Thrombus migration (TM) is frequently observed in large vessel occlusion (LVO) ischemic stroke to be treated by endovascular thrombectomy (EVT). TM may impede complete recanalization and hereby worsen clinical outcomes. This study aimed to delineate factors associated with TM and clarify its impact on technical and functional outcome.

METHODS

All patients undergoing EVT due to LVO in the anterior circulation at two tertiary stroke centers between October 2015 and December 2020 were included. Source imaging data of all individuals were assessed regarding occurrence of TM by raters blinded to clinical data. Patient data were gathered as part of the German Stroke Registry, a multicenter, prospective registry assessing real-world outcomes. Technical outcome was assessed by modified Thrombolysis in Cerebral Infarction scale (mTICI). Functional outcome was assessed by modified Rankin Scale (mRS) at 3 months.

RESULTS

The study consisted of 512 individuals, of which 71 (13.8%) displayed TM. In adjusted analyses, TM was associated with longer time from primary imaging to reassessment in the angio suite (aOR 2.37 (1.47 to 3.84) per logarithmic step) and intravenous thrombolysis (IVT; aOR 4.07 (2.17 to 7.65)). In individuals with IVT, a needle-to-groin time >1 hour was associated with higher odds for TM (aOR 2.60 (1.20 to 5.99)). TM was associated with lack of complete recanalization (aORmTICI3 0.46 (0.24 to 0.90)) but TM did not worsen odds for good clinical outcome (aORmRS≤2_d90 0.89 (0.47 to 1.68)).

CONCLUSIONS

TM is associated with IVT and longer time between sequential assessments of thrombus location. Consequently, TM may be of high relevance in patients with drip-and-ship treatment.

Association of intravenous thrombolysis and pre-interventional reperfusion: a post hoc analysis of the SWIFT DIRECT trial

BACKGROUND

A potential benefit of intravenous thrombolysis (IVT) before mechanical thrombectomy (MT) is pre-interventional reperfusion. Currently, there are few data on the occurrence of pre-interventional reperfusion in patients randomized to IVT or no IVT before MT.

METHODS

SWIFT DIRECT (Solitaire With the Intention For Thrombectomy Plus Intravenous t-PA vs DIRECT Solitaire Stent-retriever Thrombectomy in Acute Anterior Circulation Stroke) was a randomized controlled trial including acute ischemic stroke IVT eligible patients being directly admitted to a comprehensive stroke center, with allocation to IVT with MT versus MT alone. The primary endpoint of this analysis was the occurrence of pre-interventional reperfusion, defined as a pre-interventional expanded Thrombolysis in Cerebral Infarction score of ≥2a. The effect of IVT and potential treatment effect heterogeneity were analyzed using logistic regression analyses.

RESULTS

Of 396 patients, pre-interventional reperfusion occurred in 20 (10.0%) patients randomized to IVT with MT, and in 7 (3.6%) patients randomized to MT alone. Receiving IVT favored the occurrence of pre-interventional reperfusion (adjusted OR 2.91, 95% CI 1.23 to 6.87). There was no IVT treatment effect heterogeneity on the occurrence of pre-interventional reperfusion with different strata of Randomization-to-Groin-Puncture time (p for interaction=0.33), although the effect tended to be stronger in patients with a Randomization-to-Groin-Puncture time >28 min (adjusted OR 4.65, 95% CI 1.16 to 18.68). There were no significant differences in rates of functional outcomes between patients with and without pre-interventional reperfusion.

CONCLUSION

Even for patients with proximal large vessel occlusions and direct access to MT, IVT resulted in an absolute increase of 6% in rates of pre-interventional reperfusion. The influence of time strata on the occurrence of pre-interventional reperfusion should be studied further in an individual patient data meta-analysis of comparable trials.

TRIAL REGISTRATION NUMBER

clinicaltrials.gov NCT03192332.

Effect of mechanical thrombectomy with and without intravenous thrombolysis on the functional outcome of patients with different degrees of thrombus perviousness

PURPOSE

This study aimed to investigate the long-term functional outcome of patients with different degrees of thrombus perviousness (TP) undergoing mechanical thrombectomy alone and those undergoing combined intravenous thrombolysis (IVT) plus mechanical thrombectomy.

METHODS

We conducted a retrospective analysis of consecutive patients with acute ischemic stroke due to large vessel occlusion who underwent mechanical thrombectomy alone or bridging therapy between January 2016 and October 2020. TP was quantified by thrombus attenuation increase (TAI) on admission computed tomography angiography compared with non-contrast computed tomography. After dichotomization of TAI as higher or lower perviousness, Fisher exact tests were performed to estimate the associations of different therapies with favorable functional outcomes [Modified Ranking Scale score at 90 days (90-day mRS) of 0 to 2].

RESULTS

A total of 73 patients were included in our study. 35 (47.9%) thrombi were classified as higher-perviousness clots with TAI of ≥ 24 HU, and the other 38 thrombi were lower-perviousness clots. A favorable outcome with a 90-day mRS of 0 to 2 was observed in 32 patients. In patients with thrombi of lower perviousness, favorable outcome was more common in the bridging therapy group than in the thrombectomy-alone group (p = 0.013), whereas in patients with thrombi of higher perviousness, the long-term neurological outcome did not significantly differ between two therapy groups (p = 0.094).

CONCLUSION

Patients with thrombi of lower perviousness were recommended to undergo intravenous alteplase followed by endovascular thrombectomy, and those with thrombi of higher perviousness could undergo thrombectomy alone.

Early Recanalization Among Patients Undergoing Bridging Therapy With Tenecteplase or Alteplase

BACKGROUND

Intravenous thrombolysis (IVT) with alteplase or tenecteplase before mechanical thrombectomy is the recommended treatment for large-vessel occlusion acute ischemic stroke. There are divergent data on whether these agents differ in terms of early recanalization (ER) rates before mechanical thrombectomy, and little data on their potential differences stratified by ER predictors such as IVT to ER evaluation (IVT-to-EReval) time, occlusion site and thrombus length.

METHODS

We retrospectively compared the likelihood of ER after IVT with tenecteplase or alteplase in anterior circulation large-vessel occlusion acute ischemic stroke patients from the PREDICT-RECANAL (alteplase) and Tenecteplase Treatment in Ischemic Stroke (tenecteplase) French multicenter registries. ER was defined as a modified Thrombolysis in Cerebral Infarction score 2b-3 on the first angiographic run, or noninvasive vascular imaging in patients with early neurological improvement. Analyses were based on propensity score overlap weighting (leading to exact balance in patient history, stroke characteristics, and initial management between groups) and confirmed with adjusted logistic regression (sensitivity analysis). A stratified analysis based on pre-established ER predictors (IVT-to-EReval time, occlusion site, and thrombus length) was conducted.

RESULTS

Overall, 1865 patients were included. ER occurred in 156/787 (19.8%) and 199/1078 (18.5%) patients treated with tenecteplase or alteplase, respectively (odds ratio, 1.09 [95% CI, 0.83-1.44]; P=0.52). A differential effect of tenecteplase versus alteplase on the probability of ER according to thrombus length was observed (Pinteraction=0.003), with tenecteplase being associated with higher odds of ER in thrombi >10 mm (odds ratio, 2.43 [95% CI, 1.02-5.81]; P=0.04). There was no differential effect of tenecteplase versus alteplase on the likelihood of ER according to the IVT-to-EReval time (Pinteraction=0.40) or occlusion site (Pinteraction=0.80).

CONCLUSIONS

Both thrombolytics achieved ER in one-fifth of patients with large-vessel occlusion acute ischemic stroke without significant interaction with IVT-to-EReval time and occlusion site. Compared with alteplase, tenecteplase was associated with a 2-fold higher likelihood of ER in larger thrombi.

Predictors and outcome of early neurological deterioration after endovascular thrombectomy: a secondary analysis of the DIRECT-MT trial

BACKGROUND

There is uncertainty regarding the predictors of early neurological deterioration (END) after endovascular thrombectomy in patients with acute ischemic stroke (AIS). Limited studies have focused on the effect of END on functional outcome. Our aim was to determine the predictors of END after endovascular thrombectomy in AIS and its effect on functional outcome at 90 days.

METHODS

This is a secondary analysis of the DIRECT-MT trial. Patients who failed to complete endovascular thrombectomy were additionally excluded. END was defined as ≥4-point increase in National Institutes of Health Stroke Scale score between admission and 24 hours after endovascular thrombectomy. Multivariable logistic regression was used to identify predictors for END and its effect on the modified Rankin Scale (mRS) score at 90 days.

RESULTS

Of 591 patients enrolled, 111 (18.8%) had postoperative END, which was associated with higher ordinal mRS score at 90 days (adjusted common OR (aOR) 6.968, 95% CI 4.444 to 10.926). Non-modifiable factors included baseline Alberta Stroke Program Early CT Score (aOR 0.883, 95% CI 0.790 to 0.987), systolic blood pressure (aOR 1.017, 95% CI 1.006 to 1.028), glucose level (aOR 1.178, 95% CI 1.090 to 1.273), collateral status (aOR 0.238, 95% CI 0.093 to 0.608), occlusion site (aOR 0.496, 95% CI 0.290 to 0.851) and the presence of an anterior communicating artery (aOR 0.323, 95% CI 0.148 to 0.707). Admission-to-groin puncture time (aOR 1.010, 95% CI 1.003 to 1.017), general anesthesia (aOR 2.299, 95% CI 1.193 to 4.444), number of passes (aOR 1.561, 95% CI 1.243 to 1.961) and contrast extravasation (aOR 6.096, 95% CI 1.543 to 24.088) were modifiable predictors for END.

CONCLUSIONS

Postoperative END is associated with adverse functional outcome. Several non-modifiable and modifiable factors can predict END and support future treatment decision-making to improve the potential utility of endovascular thrombectomy.

TRIAL REGISTRATION NUMBER

DIRECT-MT ClinicalTrials.gov NCT03469206.

Decline of thrombolysis rates before endovascular therapy in patients with acute anterior circulation large vessel occlusion ischemic stroke: A multicenter analysis from the German Stroke Registry

INTRODUCTION

In recent years, the role of intravenous thrombolysis (IVT) before endovascular stroke treatment (EVT) has been discussed intensively. Whether the discussion was accompanied by changing rates of bridging IVT is unknown.

METHODS

Data were extracted from the prospectively maintained German Stroke Registry, including patients treated with EVT at one of 28 stroke centers in Germany between 2016 and 2021. Primary outcome parameters were the rate of bridging IVT (a) in the entire registry cohort and (b) in patients without formal contraindications to IVT (i.e. recent oral anticoagulants, time window ⩾4.5 h, extensive early ischemic changes) adjusted for demographic and clinical confounders.

RESULTS

10,162 patients (52.8% women, median age 77 years, median National Institutes of Health Stroke Scale score 14) were analyzed. In the entire cohort, the rate of bridging IVT decreased from 63.8% in 2016 to 43.6% in 2021 (average absolute annual decrease 3.1%, 95% CI 2.4%-3.8%), while the proportion of patients with at least one formal contraindication increased by only 1.2% annually (95% CI 0.6%-1.9%). Among 5460 patients without record of formal contraindications, the rate of bridging IVT decreased from 75.5% in 2016 to 63.2% in 2021 and was significantly associated with admission date in a multivariable model (average absolute annual decrease 1.4%, 95% CI 0.6%-2.2%). Clinical factors associated with lower odds of bridging IVT included diabetes mellitus, carotid-T-occlusion, dual antiplatelet therapy, and direct admission to a thrombectomy center.

CONCLUSION

We observed a substantial decline in bridging IVT rates independent of demographic confounders and not explained by an increase in contraindications. This observation deserves further exploration in independent populations.

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.

Intraarterial urokinase for thrombus migration after mechanical thrombectomy for large vessel ischemic stroke

BACKGROUND

Achieving rapid and complete reperfusion is the ultimate purpose for ischemic stroke with large vessel occlusion (LVO). Although mechanical thrombectomy (MT) had been a proverbially important procedure, medium vessel occlusion (MeVO) with thrombus migration can sporadically occur after MT. Moreover, the safe and effective approach for such had been unknown. We reported thrombolysis with intraarterial urokinase for MeVO with thrombus migration after MT.

METHODS

We included 122 patients who were treated by MT with LVO stroke at our institution between April 2019 and March 2021. Of 26 patients (21.3%) who developed MeVO with thrombus migration after MT, 11 (9.0%) underwent additional MT (MT group) and 15 (12.3%) received intraarterial urokinase (UK group). The procedure time; angiographically modified Treatment in Cerebral Ischemia Scale (mTICI); functional independence, which was defined as modified Rankin Scale 0-2, on day 30 or upon discharge; and symptomatic and asymptomatic intracerebral hemorrhage (ICH) were compared between the UK and MT groups.

RESULTS

The procedure time, mTICI, and asymptomatic ICH did not significantly differ between the groups. In the UK group, 8 of 15 (53.3%) patients obtained functional independence, and the functional independence rate was significantly higher in the UK group than in the MT group (p < 0.05). Symptomatic ICH did not occur in the UK group, and its incidence was significantly smaller than that in the MT group (p < 0.05).

CONCLUSION

The results of this study suggest that intraarterial urokinase for MeVO with thrombus migration after MT may safely improve angiographic reperfusion.

Distal Embolization in Relation to Radiological Thrombus Characteristics, Treatment Details, and Functional Outcome

BACKGROUND

Distal embolization (DE) is a common complication of endovascular treatment (EVT). We investigated the association of radiological thrombus characteristics and treatment details with DE.

METHODS

Patients with thin-slice (≤2.5 mm) baseline noncontrast computed tomography and computed tomography angiography from the ESCAPE-NA1 trial (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke) were included. Thrombus annotation was performed manually on coregistered scans by experienced readers. We assessed thrombus location, distance from internal carotid artery terminus, length, perviousness, absolute attenuation, and hyperdense artery sign. In addition, we evaluated balloon guide catheter use during EVT, first-line EVT approach, the number of thrombectomy passes, and prior intravenous thrombolysis administration. DE was defined as the occurrence of emboli distal to the target artery or in new territories during EVT. The association between thrombus characteristics, treatment details, and DE was evaluated using descriptive statistics and multivariable mixed-effects logistic regression, resulting in adjusted odds ratios (aOR) with 95% CI. Interaction between IVT and radiological thrombus characteristics was assessed by adding interaction terms in separate models.

RESULTS

In total, 496 out of 1105 (44.9%) ESCAPE-NA1 patients were included. DE was detected in 251 out of 496 patients (50.6%). Patients with DE had longer thrombi (median, 28.5 [interquartile range, 20.8-42.3] mm versus 24.4 [interquartile range, 17.1-32.4] mm; P<0.01). There were no statistically significant differences in the other thrombus characteristics. Factors associated with DE were thrombus length (aOR, 1.02 [95% CI, 1.01-1.04]), balloon guide catheter use (aOR, 0.49 [95% CI, 0.29-0.85]), and number of passes (aOR, 1.24 [95% CI, 1.04-1.47]). In patients with hyperdense artery sign, IVT was associated with reduced odds of DE (aOR, 0.55 [95% CI, 0.31-0.97]), P for interaction=0.04.

CONCLUSIONS

DE was associated with longer thrombi, no balloon guide catheter use, and more EVT passes. IVT was associated with a reduced risk of DE in patients with hyperdense artery sign. These findings may support treatment decisions on IVT and EVT approaches.

Direct Mechanical Thrombectomy Versus Prior Bridging Intravenous Thrombolysis in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

The current guideline recommends using an intravenous tissue-type plasminogen activator (IV tPA) prior to mechanical thrombectomy (MT) in eligible acute ischemic stroke (AIS) with emergent large vessel occlusion (ELVO). Some recent studies found no significant differences in the long-term functional outcomes between bridging therapy (BT, i.e., IV tPA prior to MT) and direct MT (dMT).

METHODS

We conducted a systematic review and meta-analysis to compare the safety and functional outcomes between BT and dMT in AIS patients with ELVO who were eligible for IV tPA administration. Based on the ELVO location, patients were categorized as the anterior group (occlusion of the anterior circulation), or the combined group (occlusion of the anterior and/or posterior circulation). A subgroup analysis was performed based on the study type, i.e., RCT and non-RCT.

RESULTS

Thirteen studies (3985 patients) matched the eligibility criteria. Comparing the BT and dMT groups, no significant differences in terms of mortality and good functional outcome were observed at 90 days. Symptomatic intracranial hemorrhagic (sICH) events were more frequent in BT patients in the combined group (OR = 0.73, p = 0.02); this result remained significant only in the non-RCT subgroup (OR = 0.67, p = 0.03). The RCT subgroup had a significantly higher rate of successful revascularization in BT patients (OR = 0.73, p = 0.02).

CONCLUSIONS

Our meta-analysis uncovered no significant differences in functional outcome and mortality rate at 90 days between dMT and BT in patients with AIS who had ELVO. Although BT performed better in terms of successful recanalization rate, there is a risk of increased sICH rate in this group.

A study on endovascular treatment alone and bridging treatment for acute ischemic stroke

OBJECTIVES

To investigate whether intravenous thrombolysis (IVT) with alteplase (a recombinant tissue plasminogen activator, rt-PA) before endovascular treatment (EVT) is beneficial for acute ischemic stroke (AIS) patients in different periods.

METHODS

This study enrolled a total of 140 patients hospitalized between 2019 and 2022 with AIS from large vessel occlusion (LVO) in the anterior circulation. Those patients were divided into the EVT alone group and IVT + EVT group, in which EVT was preceded by intravenous rt-PA. According to the time from onset to femoral artery puncture, the above two groups were divided into the following subgroups: < 4.5 h, between 4.5 and 6 h, between 6 and 8 h, and between 8 and 10 h. There were 78 patients in the EVT alone group and 62 patients in the IVT + EVT group.

RESULTS

There was no statistically significant difference in functional independence, recanalization rate, favorable outcome rate, or mortality between the EVT and IVT + EVT groups (P > 0.05). After adjusting for confounding factors, a lower incidence of intracerebral hemorrhage was observed in the EVT group (P < 0.05). A comparison of time-dependent efficacy between the two groups showed that within 6-8 h, there were statistically significant differences between admission and postoperation in the National Institutes of Health Stroke Scale scores at 24 h (P = 0.01) or 7 days (P = 0.02).

CONCLUSIONS

Although there was no difference in clinical efficacy and safety between the abovementioned two groups, treatment with IVT + EVT could increase the risk of bleeding compared to EVT. Moreover, in the 6-8 h subgroup, the efficacy of EVT alone was better than that of IVT + EVT.

Endovascular thrombectomy with or without intravenous alteplase in acute stroke: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND AND PURPOSE

This study investigated clinical outcomes after direct endovascular thrombectomy (EVT) compared to bridging therapy (EVT with prior intravenous alteplase) in acute stroke within 4.5 h after onset.

METHODS

PubMed and Embase were searched for eligible randomized controlled trials. The primary outcome was the rates of neurological functional independence defined as modified Rankin scale score 0-2 at 90 days, whose non-inferiority margin was set at - 15%, - 10%, - 6.5%, - 5%, and - 1.3% for its risk difference (RD).

RESULTS

We included six studies enrolling 2334 participants. The crude cumulative rates of functional independence were 49.0% with direct EVT vs 50.9% with bridging therapy, without significant difference (Odd ratio [OR] = 0.93, 95% confidence interval [CI] 0.79-1.09) between two groups, where the pooled RD was - 2% (95% CI - 6 to 2%) whose lower 95% CI bound fell within non-inferiority margins of - 15%, - 10%, -6.5%, but not - 5% and - 1.3%. Between the two groups, no significant difference was found in excellent function rate (30.2% vs 30.6%, OR = 0.99, 95% CI 0.82-1.18) with RD of 0% (95% CI - 3 to 4%), mortality rate (16.0% vs 15.0%, OR = 1.08, 95% CI 0.86-1.35) with RD of 1% (95% CI - 2 to 4%), and symptomatic intracranial hemorrhage rate (4.3% vs 5.0%, OR = 0.86, 95% CI 0.58-1.27) with RD of 0% (95% CI - 2 to 1%).

CONCLUSIONS

No statistical difference was found in functional and safety outcomes between direct EVT and bridging therapy groups in acute stroke within 4.5 h after symptom onset. EVT alone was non-inferior to bridging therapy for several, but not the more stringent, non-inferiority margins.

Intravenous thrombolysis plus mechanical thrombectomy versus mechanical thrombectomy alone for acute ischemic stroke: A systematic review and updated meta-analysis of clinical trials

BACKGROUND

Mechanical thrombectomy (MT) is the gold standard treatment for large vessel occlusion (LVO). A vital factor that might influence MT outcomes is the use of intravenous thrombolysis (IVT). A few clinical trials in this domain thus far have not yielded consistent outcomes. We conducted this meta-analysis to synthesize collective evidence in this regard.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guidelines were followed, and we performed a comprehensive literature search of four databases (PubMed, Scopus, Web of Science, Cochrane CENTRAL). For outcomes constituting continuous data, the mean difference (MD) and its standard deviation (SD) were pooled. For outcomes constituting dichotomous data, the frequency of events and the total number of patients were pooled as the risk ratio (RR).

RESULTS

Seven clinical trials with a total of 2317 patients are included in this meta-analysis. Six trials are randomized, and one trial was nonrandomized. No significant differences were found between MT plus IVT and MT alone in successful recanalization (RR 1.04, 95% Confidence Interval (CI) [0.92 to 1.17], P = 0.53), 90-day functional independence (RR 1.03, 95% CI [0.90 to 1.19], P = 0.65), symptomatic intracranial hemorrhage (sICH) (RR 1.22, 95% CI [0.84 to 1.75], P = 0.30), or mortality (RR 0.94, 95% CI [0.76 to 1.18], P = 0.61).

CONCLUSION

The current evidence does not favor either MT plus IVT or MT alone for LVO except for the procedural time. More trials are needed in this regard, and certain factors should be considered when comparing the two approaches.

Mild and moderate cardioembolic stroke patients may benefit more from direct mechanical thrombectomy than bridging therapy: A subgroup analysis of a randomized clinical trial (DIRECT-MT)

Background

The benefit of intravenous alteplase before endovascular thrombectomy is unclear in patients with acute cardioembolic stroke.

Methods

We collected cardioembolic (CE) stroke patient data from the multicentre randomized clinical trial of Direct Intra-arterial Thrombectomy to Revascularize Acute Ischaemic Stroke Patients with Large Vessel Occlusion Efficiently in Chinese Tertiary Hospitals (DIRECT-MT). The primary outcome was the 90-day modified Rankin Scale (mRS) score. Five subgroups of cardioembolic stroke patients were analyzed. A multivariable ordinal logistic regression analysis analyzed the difference in the primary outcome between the direct mechanical thrombectomy (MT) and bridging therapy groups. An interaction term was entered into the model to test for subgroup interaction. The DIRECT-MT trial is registered with clinicaltrials.gov Identifier: NCT03469206.

Results

A total of 290 CE stroke patients from the DIRECT-MT trial were enrolled in this study: 146 patients in the direct MT group and 144 patients in the bridging therapy group. No difference between the two treatment groups in the primary outcome was found (adjusted common odds ratio, 1.218; 95% confidence interval, 0.806 to 1.841; P = 0.34). In the subgroup analysis, CE stroke patients with an NIHSS ≤ 15 in the direct MT group were associated with better outcomes (47 vs. 53, acOR, 3.14 [1.497, 6.585]) and lower mortality (47 vs. 53, aOR, 0.16 [0.026, 0.986]) than those in the bridging therapy group, while there were no significant differences between the two treatment groups in the outcome and mortality of CE stroke patients with an NIHSS >15.

Conclusion

Mild and moderate cardioembolic stroke patients may benefit more from direct mechanical thrombectomy than bridging therapy. This need to be confirmed by further prospective studies in a larger number of patients.

Impact of Patency of the Carotid Terminus and Middle Cerebral Artery on Early Clinical Outcomes in Patients with Acute Internal Carotid Artery Occlusion and Mild Symptoms

INTRODUCTION

Both collateral flow via the internal carotid artery (ICA) terminus (ICT) and initial mild symptoms might be associated with favorable outcomes in patients with acute ICA occlusion (ICAO). This study aimed to address the association between early clinical outcomes and patency of the ICT and middle cerebral artery (MCA) in patients with acute ICAO with mild symptoms.

METHODS

Of 1,214 consecutive patients with acute ischemic stroke or transient ischemic attack due to large vessel occlusion, patients with ipsilateral ICAO and initial National Institutes of Health Stroke Scale (NIHSS) score ≤5 were retrospectively enrolled. We examined the associations between clinical factors including patency of the ICT and MCA and recurrence of stroke or early neurological deterioration (REND). Significant early neurological deterioration was defined as increment in NIHSS score ≥1 during hospital stay.

RESULTS

Thirteen of the 35 patients who were finally enrolled had REND (37%), and median modified Rankin scale (mRS) score at discharge was 1 (interquartile range, 0-4). Initial NIHSS score (4 vs. 1, p < 0.001) and rates of diabetes mellitus (61.5% vs. 13.6%, p = 0.007), intravenous thrombolysis (IVT) (30.9% vs. 0%, p = 0.014), and mechanical thrombectomy (MT) (23.1% vs. 0%, p = 0.044) were significantly higher in patients with REND rather than in those without. The rate of patent ICT and MCA was comparable between groups. Except for 1 patient who underwent MT promptly after IVT immediately after REND, 3 patients initially treated with IVT deteriorated after the procedure. One patient without patent ICT and MCA did not meet the indications for MT. In 2 other patients with patent ICT and MCA, MT was not initially performed, but was eventually performed because of REND due to thrombus migration, and both were discharged with an mRS score of 5.

CONCLUSION

The overall clinical outcomes of patients with acute ICAO with mild symptoms were not depending on the patency of the ICT and MCA, but initial treatment with IVT alone might risk unfavorable outcomes due to thrombus migration in patients with patent ICT and MCA.

Outcomes After Endovascular Thrombectomy With or Without Alteplase in Routine Clinical Practice

Importance

The effectiveness and safety of intravenous alteplase given before or concurrently with endovascular thrombectomy (EVT) is uncertain. Randomized clinical trials suggest there is little difference in outcomes but with only modest precision and insufficient power to analyze uncommon outcomes including symptomatic intracranial hemorrhage (sICH).

Objective

To determine whether 8 prespecified outcomes are different in patients with acute ischemic stroke treated in routine clinical practice with EVT with alteplase compared with patients treated with EVT alone without alteplase. It was hypothesized that alteplase would be associated with higher risk of sICH.

Design, Setting, and Participants

This was an observational cohort study conducted from February 1, 2019, to June 30, 2020, that included adult patients with acute ischemic stroke treated with EVT within 6 hours of time last known well, after excluding patients without information on discharge destination and patients with in-hospital stroke. Participants were recruited from Get With The Guidelines-Stroke, a large nationwide registry of patients with acute ischemic stroke from 555 hospitals in the US.

Exposures

Intravenous alteplase or no alteplase.

Main Outcomes and Measures

Prespecified outcomes were discharge destination, independent ambulation at discharge, modified Rankin score at discharge, discharge mortality, cerebral reperfusion according to modified Thrombolysis in Cerebral Infarction grade, and sICH.

Results

There were 15 832 patients treated with EVT (median [IQR] age, 72.0 [61.0-82.0] years; 7932 women [50.1%]); 10 548 (66.7%) received alteplase and 5284 (33.4%) did not. Patients treated with alteplase were younger, arrived via Emergency Medical Services sooner, were less likely to have certain comorbidities, including atrial fibrillation, hypertension, and diabetes, but had similar National Institutes of Health Stroke Severity (NIHSS) scores. Compared with patients who did not receive alteplase treatment, patients treated with alteplase were less likely to die (11.1% [1173 of 10 548 patients] vs 13.9% [734 of 5284 patients]; adjusted odds ratio [aOR] 0.83; 95% CI, 0.77-0.89; P < .001), more likely to have no major disability based on modified Rankin scale of 2 or less at discharge (28.5% [2415 of 8490 patients] vs 20.7% [894 of 4322 patients]; aOR, 1.36; 95% CI, 1.28-1.45; P < .001), and to have better reperfusion based on modified Thrombolysis in Cerebral Infarction grade 2b or greater (90.9% [8474 of 9318 patients] vs 88.0% [4140 of 4705 patients]; aOR, 1.39; 95% CI, 1.28-1.50; P < .001). However, alteplase treatment was associated with higher risk of sICH (6.5% [685 of 10 530 patients] vs 5.3% [279 of 5249 patients]; OR, 1.28; 95% CI, 1.16-1.42; P < .001).

Conclusions and Relevance

In this observational cohort study of patients treated with EVT, intravenous alteplase treatment was associated with better in-hospital survival and functional outcomes but higher sICH risk after adjusting for other covariates.

Efficacy and safety of endovascular treatment with or without intravenous alteplase in acute anterior circulation large vessel occlusion stroke: a meta-analysis of randomized controlled trials

OBJECTIVE

The current meta-analysis aimed to investigate the efficacy and safety of direct endovascular treatment (EVT) and bridging therapy (EVT with prior intravenous thrombolysis (IVT)) in patients with acute anterior circulation large vessel occlusion (LVO) stroke.

METHODS

This meta-analysis followed PRISMA guidelines. Eligible RCTs were identified through a systemic search of electronic databases (PubMed, Ovid, Web of Science, and Cochrane Library) from the inception dates to January 10, 2022. The pooled analyses were performed using RevMan 5.3 software. The primary outcome was functional outcome on the modified Rankin Scale (mRS) (range 0 to 5) at 90 days. The secondary outcomes included successful reperfusion, intracranial hemorrhage, and mortality (mRS 6) within 90 days.

RESULTS

A total of 4 RCTs involving 1633 patients were finally included. Findings of pooled analyses indicated that neither the primary outcomes (no disability (mRS 0), no significant disability despite some symptoms (mRS 1), slight disability (mRS 2), moderate disability (mRS 3), moderately severe disability (mRS 4), severe disability (mRS 5), excellent outcome (mRS 0-1), functional independence outcome (mRS 0-2), and poor outcome (mRS 3-5)) nor the secondary outcomes (successful reperfusion, intracranial hemorrhage, and mortality) in the EVT groups were not statistically significant compared with the IVT plus EVT groups (P > 0.05). In addition, the outcomes of sensitivity analysis implied that the findings of meta-analysis were credible.

CONCLUSIONS

Among patients with acute ischemic stroke due to LVO of anterior circulation, EVT alone yielded efficacy and safety outcomes similar to IVT plus EVT.

Role of Intravenous Thrombolytics Prior to Endovascular Thrombectomy

Intravenous thrombolytics and endovascular thrombectomy for ischemic stroke have evolved in parallel. However, the best approach to combine these reperfusion therapies in patients eligible for both strategies remains uncertain. Initial randomized trials of endovascular thrombectomy included administration of intravenous thrombolytics to all eligible patients. However, whether that is of net benefit has been questioned and parallels drawn with treatment of ST-segment-elevation myocardial infarction, where intravenous thrombolytics are only given if first medical contact to percutaneous intervention is expected to be >90 minutes. Six randomized trials of a direct thrombectomy approach versus intravenous thrombolytics followed by endovascular thrombectomy have now reported their results. With exception of a minority of patients in one trial, the trials all used alteplase rather than potentially more effective tenecteplase. This review examines the current state of evidence and implications for clinical practice. Importantly, these trials only apply to patients who present to a hospital with immediate access to endovascular thrombectomy and are not relevant to patients who receive thrombolytic and are then transferred to an endovascular-capable hospital. Although 2 of the 6 randomized trials met their prespecified noninferiority margin, these margins were large compared with the absolute benefit of alteplase. Overall, functional outcome was similar, with slight trends favoring bridging thrombolytics and a significant increase in final reperfusion. Symptomatic hemorrhage was increased by ≈1.8% in the bridging group but death was nonsignificantly lower. The workflow in direct thrombectomy trials involved delaying thrombolytic administration until eligibility for thrombectomy and the trials was established and randomization completed. This reduced the time available for thrombolytics to occur prethrombectomy compared with standard practice. We conclude that, pending individual-patient data meta-analyses, intravenous thrombolytics retain an important role alongside endovascular thrombectomy. Further efforts to accelerate and enhance reperfusion with thrombolytics and perform individual patient-level pooled subgroup analyses are warranted.

Association of Intravenous Alteplase, Early Reperfusion, and Clinical Outcome in Patients With Large Vessel Occlusion Stroke: Post Hoc Analysis of the Randomized DIRECT-MT Trial

BACKGROUND

The added value of intravenous alteplase in reperfusing ischemic brain tissue in patients undergoing endovascular treatment and directly presented to an endovascular treatment-capable hospital is uncertain. We conducted this post hoc analysis of a randomized trial (DIRECT-MT [Direct Intraarterial Thrombectomy in Order to Revascularize Acute Ischemic Stroke Patients With Large Vessel Occlusion Efficiently in Chinese Tertiary Hospitals: A Multicenter Randomized Clinical Trial]) to explore the association of intravenous alteplase, early (preendovascular treatment) reperfusion, and clinical outcome and to determine factors which may modify alteplase treatment effect on early reperfusion.

METHODS

In this post hoc analysis of the DIRECT-MT randomized trial comparing intravenous alteplase before endovascular treatment versus endovascular treatment only, 623 of 656 randomized patients, with adequate angiographic evaluation for early reperfusion assessment, were included. The association of intravenous alteplase and early reperfusion (defined as expanded Thrombolysis in Cerebral Infarction score ≥2a on angiogram) was assessed using unadjusted comparisons and multivariable logistic regression.

RESULTS

Among 623 patients included (317 received intravenous alteplase and 306 did not), early reperfusion occurred in 91 (15%) patients and was associated with better functional outcome (modified Rankin Scale score, 0-2 of 49/91 [54%] versus 178/531 [34%]; adjusted odds ratio, 1.92 [95% CI, 1.15-3.21]; P<0.001). Intravenous alteplase was independently associated with early reperfusion (59/317 [19%] versus 32/306 [10%]; adjusted odds ratio, 2.06 [95% CI, 1.27-3.33]; P=0.003), and the alteplase effect was modified by time from randomization to groin puncture (dichotomized by median, ≤33 minutes; adjusted odds ratio, 1.06 [95% CI, 0.53-2.10] versus >33 minutes; adjusted odds ratio, 4.07 [95% CI, 1.86-8.86]; Pinteraction=0.012).

CONCLUSIONS

For patients with large vessel occlusion directly presenting to an endovascular treatment-capable hospital, intravenous alteplase increases early reperfusion when endovascular treatment gets delayed more than approximately half an hour. Thus, intravenous alteplase should be considered if endovascular treatment delays are anticipated by the treating medical team.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03469206.

Cost-effective analysis of mechanical thrombectomy alone in the treatment of acute ischaemic stroke: a Markov modelling study

OBJECTIVE

Recently, a randomised controlled trial (DIRECT-MT) demonstrated that mechanical thrombectomy (MT) was non-inferior to MT with intravenous alteplase as to the functional outcomes. This study aims to investigate whether MT alone is cost-effective compared with MT with alteplase in China.

METHODS

A Markov decision analytic model was built from the Chinese healthcare perspective using a lifetime horizon. Probabilities, costs and outcomes data were obtained from the DIRECT-MT trial and other most recent/comprehensive literature. Base case calculation was conducted to compare the costs and effectiveness between MT alone and MT with alteplase. One-way and probabilistic sensitivity analyses were performed to evaluate the robustness of the results.

RESULTS

MT alone had a lower cost and higher effectiveness compared with MT with alteplase. The probabilistic sensitivity analysis demonstrated that, over a lifetime horizon, MT alone had a 99.5% probability of being cost-effective under the willingness-to-pay threshold of 1× gross domestic product per capita in China based on data obtained from the DIRECT-MT trial. These results remained robust under one-way sensitivity analysis.

CONCLUSIONS

MT alone was cost-effective compared with MT with alteplase in China. However, cautions are needed to extend this conclusion to regions outside of China.

Effect of stroke etiology on endovascular thrombectomy with or without intravenous alteplase: a subgroup analysis of DIRECT-MT

BACKGROUND

Stroke etiology might influence the clinical outcomes in patients with large vessel occlusion receiving endovascular treatment (EVT) with or without thrombolysis.

OBJECTIVE

To examine whether stroke etiology resulted in different efficacy and safety in patients treated with EVT-alone or EVT preceded by intravenous alteplase (combined therapy).

METHODS

We assessed the efficacy and safety of treatment strategy based on prespecified stroke etiology, cardioembolism (CE), large-artery atherosclerosis (LAA), and undetermined cause (UC) for patients enrolled in the DIRECT-MT trial. The primary outcome was the modified Rankin Scale (mRS) score at 90 days. Multivariate ordinal logistic regression analysis was used to calculate the adjusted common OR for a shift of better mRS score for EVT-alone versus combined therapy. A term was entered to test for interaction.

RESULTS

In this study, 656 patients were grouped into three prespecified stroke etiologic subgroups. The adjusted common ORs for improvement in the 90-day ordinal mRS score with EVT-alone were 1.2 (95% CI 0.8 to 1.8) for CE, 1.6 (95% CI 0.8 to 3.3) for LAA, and 0.8 (95% CI 0.5 to 1.3) for UC. Compared with CE, EVT-alone was more likely to result in an mRS score of 0-1 (p_interaction=0.047) and extended Thrombolysis in Cerebral Infarction ≥2b (p_interaction=0.041) in the LAA group. The differences in mortality and symptomatic intracranial hemorrhage within 90 days were not significant between the subgroups (p＞0.05).

CONCLUSIONS

The results did not support the hypothesis that a specific treatment strategy based on stroke etiology should be used for patients with large vessel occlusion (NCT03469206).

Effect of Occlusion Site on the Safety and Efficacy of Intravenous Alteplase Before Endovascular Thrombectomy: A Prespecified Subgroup Analysis of DIRECT-MT

BACKGROUND AND PURPOSE

Recent trials showed thrombectomy alone was comparable to bridging therapy in patients with anterior circulation large vessel occlusion eligible for both intravenous alteplase and endovascular thrombectomy. We performed this study to examine whether occlusion site modifies the effect of intravenous alteplase before thrombectomy.

METHODS

This is a prespecified subgroup analysis of a randomized trial evaluating risk and benefit of intravenous alteplase before thrombectomy (DIRECT-MT [Direct Intra-Arterial Thrombectomy in Order to Revascularize AIS Patients With Large Vessel Occlusion Efficiently in Chinese Tertiary Hospitals]). Among 658 randomized patients, 640 with baseline occlusion site information were included. The primary outcome was the score on the modified Rankin Scale at 90 days. Multivariable ordinal logistic regression analysis with an interaction term was used to estimate treatment effect modification by occlusion location (internal carotid artery versus M1 versus M2). We report the adjusted common odds ratio for a shift toward better outcome on the modified Rankin Scale after thrombectomy alone compared with combination treatment adjusted for age, the National Institutes of Health Stroke Scale score at baseline, the time from stroke onset to randomization, the modified Rankin Scale score before stroke onset, and collateral score per the DIRECT-MT statistical analysis plan.

RESULTS

The overall adjusted common odds ratio was 1.08 (95% CI, 0.82-1.43) with thrombectomy alone compared with combination treatment, and there was no significant treatment-by-occlusion site interaction (P=0.47). In subgroups based on occlusion location, we found the following adjusted common odds ratios: 0.99 (95% CI, 0.62-1.59) for internal carotid artery occlusions, 1.12 (95% CI, 0.77-1.64) for M1 occlusions, and 1.22 (95% CI, 0.53-2.79) for M2 occlusions. No treatment-by-occlusion site interactions were observed for dichotomized modified Rankin Scale distributions and successful reperfusion (extended thrombolysis in Cerebral Infarction score ≥2b) before thrombectomy. Differences in symptomatic hemorrhage rate were not significant between occlusion locations (internal carotid artery occlusion: 7.02% in bridging therapy versus 7.14% for thrombectomy alone, P=0.97; M1 occlusion: 5.06% versus 2.48%, P=0.22; M2 occlusion: 9.09% versus 4.76%; P=0.78).

CONCLUSIONS

In this prespecified subgroup of a randomized trial, we found no evidence that occlusion location can inform intravenous alteplase decisions in endovascular treatment eligible patients directly presenting at endovascular treatment capable centers. Future studies are needed to confirm our findings. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03469206.

Aspects of ischemic stroke biomechanics derived using ex-vivo and in-vitro methods relating to mechanical thrombectomy

Establishing the underlying biomechanics of acute ischemic stroke (AIS) and its treatment is fundamental to developing more effective clinical treatments for one of society's most impactful diseases. Recent changes in AIS management, driven by clinical evidence of improved treatments, has already led to a rapid rate of innovation, which is likely to be sustained for many years to come. These unprecedented AIS triage and treatment innovations provide a great opportunity to better understand the disease. In this article we provide a perspective on the recreation of AIS in the laboratory to inform contemporary device design and procedural techniques in mechanical thrombectomy. Presentation of these findings, which have been used to solve the applied problem of designing mechanical thrombectomy devices, is intended to help inform the development of basic biomechanics solutions for AIS.

Measuring the effect of thrombosis, thrombus maturation and thrombolysis on clot mechanical properties in an in-vitro model

Changes in acute ischemic stroke thrombi structure and composition may result in significant differences in treatment responsiveness. Ischemic stroke patients are often treated with a thrombolytic agent to dissolve thrombi, however these patients may subsequently undergo mechanical thrombectomy to remove the occlusive clot. We set out to determine if rt-PA thrombolysis treatment of blood clots changes their mechanical properties, which in turn may impact mechanical thrombectomy. Using a design-of-experiment approach, ovine clot analogues were prepared with varying composition and further exposed to different levels of compaction force to simulate the effect of arterial blood pressure. Finally, clots were treated with three r-tPA doses for different durations. Clot mass and mechanical behaviour was analysed to assess changes due to (i) Platelet driven contraction (ii) Compaction force and (iii) Thrombolysis. Clots that were exposed to r-tPA for longer duration showed significant reduction in clot mass (p < 0.001). Exposure time to r-tPA (p < 0.001) was shown to be an independent predictor of lower clot stiffness. A decrease in energy dissipation ratio during mechanical compression was associated with longer exposure time in r-tPA (p = 0.001) and a higher platelet concentration ratio (p = 0.018). The dose of r-tPA was not a significant factor in reducing clot mass or changing mechanical properties of the clots. Fibrinolysis reduces clot stiffness which may explain increased distal clot migration observed in patients treated with r-tPA and should be considered as a potential clot modification factor before mechanical thrombectomy.

Functional Outcome, Recanalization, and Hemorrhage Rates After Large Vessel Occlusion Stroke Treated With Tenecteplase Before Thrombectomy

BACKGROUND AND OBJECTIVES

To investigate in routine care the efficacy and safety of IV thrombolysis (IVT) with tenecteplase prior to mechanical thrombectomy (MT) in patients with large vessel occlusion acute ischemic strokes (LVO-AIS), either secondarily transferred after IVT or directly admitted to a comprehensive stroke center (CSC).

METHODS

We retrospectively analyzed clinical and procedural data of patients treated with 0.25 mg/kg tenecteplase within 270 minutes of LVO-AIS who underwent brain angiography. The main outcome was 3-month functional independence (modified Rankin Scale score ≤2). Recanalization (revised Treatment in Cerebral Ischemia score 2b-3) was evaluated before (pre-MT) and after MT (final).

RESULTS

We included 588 patients (median age 75 years [interquartile range (IQR) 61-84]; 315 women [54%]; median NIH Stroke Scale score 16 [IQR 10-20]), of whom 520 (88%) were secondarily transferred after IVT. Functional independence occurred in 47% (n = 269/570; 95% confidence interval [CI] 43.0-51.4) of patients. Pre-MT recanalization occurred in 120 patients (20.4%; 95% CI 17.2-23.9), at a similar rate across treatment paradigms (direct admission, n = 14/68 [20.6%]; secondary transfer, n = 106/520 [20.4%]; p > 0.99) despite a shorter median IVT to puncture time in directly admitted patients (38 [IQR 23-55] vs 86 [IQR 70-110] minutes; p < 0.001). Final recanalization was achieved in 492 patients (83.7%; 95%CI 80.4-86.6). Symptomatic intracerebral hemorrhage occurred in 2.5% of patients (n = 14/567; 95% CI 1.4-4.1).

DISCUSSIONS

Tenecteplase before MT is safe, effective, and achieves a fast recanalization in everyday practice in patients secondarily transferred or directly admitted to a CSC, in line with published results. These findings should encourage its wider use in bridging therapy.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that tenecteplase within 270 minutes of LVO-AIS increases the probability of functional independence.

Quantitative analysis of thrombus migration before mechanical thrombectomy: Determinants and relationship with procedural and clinical outcomes

BACKGROUND AND PURPOSE

In patients with acute ischemic stroke (AIS) and a large vessel occlusion (LVO), thrombus migration (T-Mig) is a common phenomenon before mechanical thrombectomy (MT), revealed by pre-treatment imaging. Previous works have used qualitative scales to define T-Mig. The aim of this study was to evaluate the determinants and impact of quantitatively assessed T-Mig on procedural characteristics and clinical outcome.

METHODS

Consecutive patients with AIS due to LVO treated by MT at a reference academic hospital were analysed. Distance between vessel origin and beginning of the thrombus on MRI (3D-time-of-flight and/or contrast-enhanced magnetic-resonance-angiography) and digital-substracted-angiography (DSA) were measured in millimeters using a curve tool. Thrombus migration was defined quantitatively as ∆TD calculated as the difference between pre-MT-DSA and MRI thrombus location. ∆TD was rated as significant if above 5mm.

RESULTS

A total of 267 patients were included (mean age 70±12 years; 46% females) were analyzed. Amongst them, 65 (24.3%) experienced any degree of T-Mig. T-Mig was found to be associated with iv-tPA administration prior to thrombectomy (β-estimate 2.52; _95% CI [1.25-3.79]; p<0.001), fewer device passes during thrombectomy (1.22±1.31 vs 1.66±0.99; p<0.05), and shorter pre-treatment thrombi (β-estimate -0.1millimeter; _95% CI [-0.27-0.07]; p<0.05). There was no association between T-Mig and a favourable outcome (defined by a 0-to-2 modified-Rankin-Scale at 3months, adjusted OR: 2.16 [0.93 - 5.02]; p=0.06) CONCLUSION: Thrombus migration happens in almost a fourth of our study sample, and its quantitative extent was associated with iv-tPA administration prior to MT, but not with clinical outcome.

Difference of Thrombus Location between Initial Noninvasive Vascular Image and First DSA Findings in Mechanical Thrombectomy for Intracranial Large Vessel Occlusion: Post Hoc Analysis of the SKIP Study

In patients who undergo mechanical thrombectomy for intracranial large vessel occlusion, the occluded site is sometimes distal to the site shown in the initial vascular imaging. We investigated the factors related to the change in the occluded site between the sequential imagings. The 203 patients in the SKIP study were reviewed retrospectively. Magnetic resonance angiography (MRA) or computed tomography angiography (CTA) was used to assess the occluded site. The occluded site shown in the cerebral angiography appeared to be distal to the occluded site shown in the initial vascular imaging in 55 patients (group A). The location of the occluded site in the remaining 148 patients did not change between the sequential imagings (group B). MRA was used more often than CTA in group A (54 MRA, 1 CTA; P <0.01). Patients with middle cerebral artery (M1) occlusion were more likely to show change of the occluded site than patients with internal carotid artery (ICA) occlusion (M1: 38%, ICA: 9%; P <0.01). The number of patients who received intravenous recombinant tissue plasminogen activator did not differ between the two groups (group A: 54%, group B: 49%; P = 0.5). In patients with acute intracranial large vessel occlusion who require mechanical thrombectomy, physicians should be aware that the location of the thrombus may be distal to the occluded site shown in the initial vascular imaging, particularly in patients with M1 occlusion shown by MRA.

Perceived Limits of Endovascular Treatment for Secondary Medium-Vessel-Occlusion Stroke

BACKGROUND AND PURPOSE

Thrombus embolization during mechanical thrombectomy occurs in up to 9% of cases, making secondary medium vessel occlusions of particular interest to neurointerventionalists. We sought to gain insight into the current endovascular treatment approaches for secondary medium vessel occlusion stroke in an international case-based survey because there are currently no clear recommendations for endovascular treatment in these patients.

MATERIALS AND METHODS

Survey participants were presented with 3 cases involving secondary medium vessel occlusions, each consisting of 3 case vignettes with changes in the patient's neurologic status (improvement, no change, unable to assess). Multivariable logistic regression analyses clustered by the respondent's identity were used to assess factors influencing the decision to treat.

RESULTS

In total, 366 physicians (56 women, 308 men, 2 undisclosed) from 44 countries provided 3294 responses to 9 scenarios. Most (54.1%, 1782/3294) were in favor of endovascular treatment. Participants were more likely to treat occlusions in the anterior M2/3 (74.3%; risk ratio = 2.62; 95% CI, 2.27-3.03) or A3 (59.7%; risk ratio = 2.11; 95% CI, 1.83-2.42) segment compared with the M3/4 segment (28.3%; reference). Physicians were less likely to pursue endovascular treatment in patients who showed neurologic improvement than in patients with an unchanged neurologic deficit (49.9% versus 57.0% responses in favor of endovascular treatment, respectively; risk ratio = 0.88, 95% CI, 0.83-0.92). Interventionalists and more experienced physicians were more likely to treat secondary medium vessel occlusions.

CONCLUSIONS

Physicians' willingness to treat secondary medium vessel occlusions endovascularly is limited and varies per occlusion location and change in neurologic status. More evidence on the safety and efficacy of endovascular treatment for secondary medium vessel occlusion stroke is needed.

In silico trials for treatment of acute ischemic stroke: Design and implementation

An in silico trial simulates a disease and its corresponding therapies on a cohort of virtual patients to support the development and evaluation of medical devices, drugs, and treatment. In silico trials have the potential to refine, reduce cost, and partially replace current in vivo studies, namely clinical trials and animal testing. We present the design and implementation of an in silico trial for treatment of acute ischemic stroke. We propose an event-based modelling approach for the simulation of a disease and injury, where changes to the state of the system (the events) are assumed to be instantaneous. Using this approach we are able to combine a diverse set of models, spanning multiple time scales, to model acute ischemic stroke, treatment, and resulting brain tissue injury. The in silico trial is designed to be modular to aid development and reproducibility. It provides a comprehensive framework for application to any potential in silico trial. A statistical population model is used to generate cohorts of virtual patients. Patient functional outcomes are also predicted with a statistical model, using treatment and injury results and the patient's clinical parameters. We demonstrate the functionality of the event-based modelling approach and trial framework by running proof of concept in silico trials. The proof of concept trials simulate the same cohort of patients twice: once with successful treatment (successful recanalisation) and once with unsuccessful treatment (unsuccessful treatment). Ways to overcome some of the challenges and difficulties in setting up such an in silico trial are discussed, such as validation and computational limitations.

[Border areas of thrombectomy]

Mechanical thrombectomy (MT) has become the standard procedure in the treatment of patients with acute ischemic stroke (AIS) due to occlusion of a large proximal cerebral artery of the anterior circulation. Nevertheless, according to the current guidelines large patient collectives are still excluded from this highly effective treatment method. Therefore, this article gives an overview of possible extensions of the indications for treatment with MT. For example, patients in the extended time window with distal occlusions, with large infarct cores and also for very old (90+ years) or young (0-17 years) patients. Furthermore, we discuss recent developments in the interventional treatment of stroke, such as new triage concepts or the question whether an additional intravenous thrombolysis is necessary in patients with MT. We conclude with our own estimations for the discussed indications for treatment based on our clinical experience and the current literature.

Thrombectomy for secondary distal, medium vessel occlusions of the posterior circulation: seeking complete reperfusion

BACKGROUND

Whether to approach distal occlusions endovascularly or not in medium-sized vessels secondary to proximal large vessel occlusion stroke remains unanswered.

OBJECTIVE

To investigates the technical feasibility and safety of thrombectomy for secondary posterior circulation distal, medium vessel occlusions (DMVO).

METHODS

TOPMOST (Treatment fOr Primary Medium vessel Occlusion STroke) is an international, retrospective, multicenter, observational registry of patients treated for distal cerebral artery occlusions. This study subanalysis endovascularly treated occlusions of the posterior cerebral artery in the P2 and P3 segment secondary preprocedural or periprocedural thrombus migration between January 2014 and June 2020. Technical feasibility was evaluated with the modified Thrombolysis in Cerebral Infarction (mTICI) scale. Procedural safety was assessed by the occurrence of symptomatic intracranial hemorrhage (sICH) and intervention-related serious adverse events.

RESULTS

Among 71 patients with secondary posterior circulation DMVO who met the inclusion criteria, occlusions were present in 80.3% (57/71) located in the P2 segment and in 19.7% (14/71) in the P3 segment. Periprocedural migration occurred in 54.9% (39/71) and preprocedural migration in 45.1% (32/71) of cases. The first reperfusion attempt led in 38% (27/71) of all cases to mTICI 3. On multivariable logistic regression analysis, increased numbers of reperfusion attempts (adjusted odds ratio (aOR)=0.39, 95% CI 0.29 to 0.88, p=0.009) and preprocedural migration (aOR=4.70, 95% CI,1.35 to 16.35, p=0.015) were significantly associated with mTICI 3. sICH occurred in 2.8% (2/71).

CONCLUSION

Thrombectomy for secondary posterior circulation DMVO seems to be safe and technically feasible. Even though thrombi that have migrated preprocedurally may be easier to retract, successful reperfusion can be achieved in the majority of patients with secondary DMVO of the P2 and P3 segment.

Endovascular thrombectomy without versus with intravenous thrombolysis in acute ischemic stroke: a non-inferiority meta-analysis of randomized clinical trials

OBJECTIVE

To conduct a meta-analysis of randomized trials to comprehensively compare the effect of endovascular thrombectomy (EVT) versus intravenous thrombolysis (IVT) plus EVT on functional independence (modified Rankin Scale (mRS) 0-2) after acute ischemic stroke due to large vessel occlusions (AIS-LVO).

METHODS

We searched Pubmed, EMBASE, CENTRAL, and clinicaltrials.gov from January 2000 to February 2021 and abstracts presented at the International Stroke Conference in March 2021 to identify trials comparing EVT alone versus IVT plus EVT in AIS-LVO. Five non-inferiority margins established in the literature were assessed: -15%, -10%, -6.5%, -5%, and -1.3% for the risk difference for functional independence at 90 days.

RESULTS

Four trials met the selection criteria, enrolling 1633 individuals, with 817 participants randomly assigned to EVT alone and 816 to IVT plus EVT. Crude cumulative rates of 90-day functional independence were 46.0% with EVT alone versus 45.5% with IVT plus EVT. Pooled results showed the risk difference of functional independence was 1% (95% CI -4% to 5%) between EVT alone versus IVT plus EVT. The lower 95% CI bound of -4% fell within the non-inferiority margins of -15%, -10%, -6.5%, and -5%, but not -1.3%. Pooled results also showed the risk difference between EVT alone versus IVT plus EVT was 1% (95% CI -3% to 5%) for mRS 0-1, and 1% (95% CI -1% to 3%) for symptomatic intracranial hemorrhage.

CONCLUSIONS

This meta-analysis suggests that EVT alone is non-inferior to IVT plus EVT for several, but not the most stringent, non-inferiority margins.