Infarct in a New Territory After Treatment Administration in the ESCAPE Randomized Controlled Trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times)

Pharmacological preclinical comparison of tenecteplase and alteplase for the treatment of acute stroke

Alteplase (rtPA) remains the standard thrombolytic drug for acute ischemic stroke. However, new rtPA-derived molecules, such as tenecteplase (TNK), with prolonged half-lives following a single bolus administration, have been developed. Although TNK is currently under clinical evaluation, the limited preclinical data highlight the need for additional studies to elucidate its benefits. The toxicities of rtPA and TNK were evaluated in endothelial cells, astrocytes, and neuronal cells. In addition, their in vivo efficacy was independently assessed at two research centers using an ischemic thromboembolic mouse model. Both therapies were tested via early (20 and 30 min) and late administration (4 and 4.5 h) after stroke. rtPA, but not TNK, caused cell death only in neuronal cultures. Mice were less sensitive to thrombolytic therapies than humans, requiring doses 10-fold higher than the established clinical dose. A single bolus dose of 2.5 mg/kg TNK led to an infarct reduction similar to perfusion with 10 mg/kg of rtPA. Early administration of TNK decreased the hemorrhagic transformations compared to that by the early administration of rtPA; however, this result was not obtained following late administration. These two independent preclinical studies support the use of TNK as a promising reperfusion alternative to rtPA.

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.

Dual-Energy Computed Tomography in Stroke Imaging : Value of a New Image Acquisition Technique for Ischemia Detection after Mechanical Thrombectomy

OBJECTIVE

To assess if a new dual-energy computed tomography (DECT) technique enables an improved visualization of ischemic brain tissue after mechanical thrombectomy in acute stroke patients.

MATERIAL AND METHODS

The DECT head scans with a new sequential technique (TwinSpiral DECT) were performed in 41 patients with ischemic stroke after endovascular thrombectomy and were retrospectively included. Standard mixed and virtual non-contrast (VNC) images were reconstructed. Infarct visibility and image noise were assessed qualitatively by two readers using a 4-point Likert scale. Quantitative Hounsfield units (HU) were used to assess density differences of ischemic brain tissue versus healthy tissue on the non-affected contralateral hemisphere.

RESULTS

Infarct visibility was significantly better in VNC compared to mixed images for both readers R1 (VNC: median 1 (range 1-3), mixed: median 2 (range 1-4), p < 0.05) and R2 (VNC: median 2 (range 1-3), mixed: 2 (range 1-4), p < 0.05). Qualitative image noise was significantly higher in VNC compared to mixed images for both readers R1 (VNC: median 3, mixed: 2) and R2 (VNC: median 2, mixed: 1, p < 0.05, each). Mean HU were significantly different between the infarcted tissue and the reference healthy brain tissue on the contralateral hemisphere in VNC (infarct 24 ± 3) and mixed images (infarct 33 ± 5, p < 0.05, each). The mean HU difference between ischemia and reference in VNC images (mean 8 ± 3) was significantly higher (p < 0.05) compared to the mean HU difference in mixed images (mean 5 ± 4).

CONCLUSION

TwinSpiral DECT allows an improved qualitative and quantitative visualization of ischemic brain tissue in ischemic stroke patients after endovascular treatment.

Predictors of tissue infarction from distal emboli after mechanical thrombectomy

BACKGROUND

Distal embolization after endovascular thrombectomy (EVT) is common. We aimed to determine factors associated with tissue infarction in the territories of distal emboli.

METHODS

This is a retrospective cohort study of consecutive patients with anterior circulation large vessel occlusions who underwent EVT from 2015 to 2021. Patients with Thrombolysis In Cerebral Infarction (TICI) 2b reperfusion and follow-up imaging were identified. Baseline characteristics, procedural details, and imaging findings were reviewed. Primary outcome was categorized according to the occurrence of infarction at the territory of distal embolus on follow-up diffusion-weighted imaging MRI.

RESULTS

Of 156 subjects, 97 (62%) had at least one infarction in the territories at risk. Hypertension was significantly more prevalent in the infarct group (83% vs 53%, P=0.001). General anesthesia was more commonly used in the infarct group (60% vs 43%, P=0.037). The median number of distal emboli and diameter of the occluded vessel were similar. After adjusting for confounders, hypertension (aOR 4.73, 95% CI 1.81 to 13.25, P=0.002), higher blood glucose (aOR 1.01, 95% CI 1.00 to 1.03, P=0.023), and general anesthesia (aOR 2.75, 95% CI 1.15 to 6.84, P=0.025) were independently associated with infarction. The presence of angiographic leptomeningeal collaterals predicted tissue survival (aOR 0.13, 95% CI 0.05 to 0.33, P<0.001). 90-day modified Rankin scale (mRS) scores were worse for the infarction patients (mRS 0-2: infarct, 39% vs 55%, P=0.046).

CONCLUSIONS

Nearly 40% of patients with TICI 2b had no tissue infarction in the territory of a distal embolus. The association of infarction with hypertension and general anesthesia suggests late or post-procedural blood pressure management could be a modifiable factor. Patients with poor leptomeningeal collaterals or hyperglycemia may benefit from further attempts at revascularization.

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.

Multivariable Prediction Model for Futile Recanalization Therapies in Patients With Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

Very poor outcome despite IV thrombolysis (IVT) and mechanical thrombectomy (MT) occurs in approximately 1 of 4 patients with ischemic stroke and is associated with a high logistic and economic burden. We aimed to develop and validate a multivariable prognostic model to identify futile recanalization therapies (FRTs) in patients undergoing those therapies.

METHODS

Patients from a prospectively collected observational registry of a single academic stroke center treated with MT and/or IVT were included. The data set was split into a training (N = 1,808, 80%) and internal validation (N = 453, 20%) cohort. We used gradient boosted decision tree machine learning models after k-nearest neighbor imputation of 32 variables available at admission to predict FRT defined as modified Rankin scale 5-6 at 3 months. We report feature importance, ability for discrimination, calibration, and decision curve analysis.

RESULTS

A total of 2,261 patients with a median (interquartile range) age of 75 years (64-83 years), 46% female, median NIH Stroke Scale 9 (4-17), 34% IVT alone, 41% MT alone, and 25% bridging were included. Overall, 539 (24%) had FRT, more often in MT alone (34%) as compared with IVT alone (11%). Feature importance identified clinical variables (stroke severity, age, active cancer, prestroke disability), laboratory values (glucose, C-reactive protein, creatinine), imaging biomarkers (white matter hyperintensities), and onset-to-admission time as the most important predictors. The final model was discriminatory for predicting 3-month FRT (area under the curve 0.87, 95% CI 0.87-0.88) and had good calibration (Brier 0.12, 0.11-0.12). Overall performance was moderate (F1-score 0.63 ± 0.004), and decision curve analyses suggested higher mean net benefit at lower thresholds of treatment (up to 0.8).

CONCLUSIONS

This FRT prediction model can help inform shared decision making and identify the most relevant features in the emergency setting. Although it might be particularly useful in low resource healthcare settings, incorporation of further multifaceted variables is necessary to further increase the predictive performance.

Association of reperfusion success and emboli in new territories with long term mortality after mechanical thrombectomy

BACKGROUND

The degree of reperfusion is the most important modifiable predictor of 3 month functional outcome and mortality in ischemic stroke patients treated with mechanical thrombectomy. Whether the beneficial effect of reperfusion also leads to a reduction in long term mortality is unknown.

METHODS

Patients undergoing mechanical thrombectomy between January 2010 and December 2018 were included. The post-thrombectomy degree of reperfusion and emboli in new territories were core laboratory adjudicated. Reperfusion was evaluated according to the expanded Thrombolysis in Cerebral Infarction (eTICI) scale. Vital status was obtained from the Swiss population register. Adjusted hazard ratios (aHRs) using time split Cox regression models were calculated. Subgroup analyses were performed in patients with borderline indications.

RESULTS

Our study included 1264 patients (median follow-up per patient 2.5 years). Patients with successful reperfusion had longer survival times, attributable to a lower hazard of death within 0-90 days and for >90 days to 2 years (aHR 0.34, 95% CI 0.26 to 0.46; aHR 0.37, 95% CI 0.22 to 0.62). This association was homogeneous across all predefined subgroups (p for interaction >0.05). Among patients with successful reperfusion, a significant difference in the hazard of death was observed between eTICI2b50 and eTICI3 (aHR 0.51, 95% CI 0.33 to 0.79). Emboli in new territories were present in 5% of patients, and were associated with increased mortality (aHR 2.3, 95% CI 1.11 to 4.86).

CONCLUSION

Successful, and ideally complete, reperfusion without emboli in new territories is associated with a reduction in long term mortality in patients treated with mechanical thrombectomy, and this was evident across several subgroups.

Outcomes after reperfusion therapies in patients with ACA stroke: A multicenter cohort study from the EVATRISP collaboration

BACKGROUND

Patients with stroke secondary to occlusions of the anterior cerebral artery (ACA) often have poor outcomes. The optimal acute therapeutic intervention for these patients remains unknown.

METHODS

Patients with isolated ACA-stroke were identified from 10 centers participating in the EndoVascular treatment And ThRombolysis in Ischemic Stroke Patients (EVATRISP) prospective registry. Patients treated with endovascular thrombectomy (EVT) were compared to those treated with intravenous thrombolysis (IVT). Odds ratios with 95% confidence intervals (OR; 95%CI) were calculated using multivariate regression analysis.

RESULTS

Included were 92 patients with ACA-stroke. Of the 92 ACA patients, 55 (60%) were treated with IVT only and 37 (40%) with EVT (±bridging IVT). ACA patients treated with EVT had more often wake-up stroke (24% vs. 6%, p = 0.044) and proximal ACA occlusions (43% vs. 24%, p = 0.047) and tended to have higher stroke severity on admission [NIHSS: 10.0 vs 7.0, p = 0.054). However, odds for favorable outcome, mortality or symptomatic intracranial hemorrhage did not differ significantly between both groups. Exploration of the effect of clot location inside the ACA showed that in patients with A1 or A2/A3 ACA occlusions the chances of favorable outcome were not influenced by treatment allocation to IVT or EVT.

DISCUSSION

Treatment with either IVT or EVT could be safe with similar effect in patients with ACA-strokes and these effects may be independent of clot location within the occluded ACA.

Endovascular treatment with or without intravenous alteplase for acute ischaemic stroke due to basilar artery occlusion

Background and purpose

It remains controversial if endovascular treatment (EVT) can improve the outcome of patients with acute basilar artery occlusion (BAO). This study aims to compare the functional outcomes between EVT with and without intravenous thrombolysis (IVT) first in patients who had acute ischaemic stroke (AIS) due to BAO.

Methods

Patients who had AIS with BAO who underwent EVT within 24 hours of onset were enrolled in this multicentre cohort study, and the efficacy and safety were compared between IVT+EVT and direct EVT. The primary outcome was 90-day functional independence. All outcomes were assessed with adjusted OR (aOR) from the multivariable logistic regression. In addition, a meta-analysis was performed on all recently published pivotal studies on functional independence after EVT in patients with BAO.

Results

Of 310 enrolled patients with BAO, 241 (78%) were treated with direct EVT and 69 (22%) with IVT+EVT. Direct EVT was associated with a worse functional outcome (aOR, 0.46 (95% CI 0.24 to 0.85), p=0.01). IVT+EVT was associated with a lower percentage of patients who needed ≥3 passes of stent retriever (10.14% vs 20.75%). The meta-analysis regression revealed a potential positive correlation between bridging with IVT first and functional independence (r=0.14 (95% CI 0.05 to 0.24), p<0.01).

Conclusions

This study showed that compared with direct EVT, EVT with IVT first was associated with better functional outcomes in patients with BAO treated within 24 hours of onset. The meta-analysis demonstrated similar favourable efficacy of IVT first followed by EVT in patients with BAO.

Assessment of Discrepancies Between Follow-up Infarct Volume and 90-Day Outcomes Among Patients With Ischemic Stroke Who Received Endovascular Therapy

IMPORTANCE

Some patients have poor outcomes despite small infarcts after endovascular therapy (EVT), while others with large infarcts do well. Understanding why these discrepancies occur may help to optimize EVT outcomes.

OBJECTIVE

To validate exploratory findings from the Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times (ESCAPE) trial regarding pretreatment, treatment-related, and posttreatment factors associated with discrepancies between follow-up infarct volume (FIV) and 90-day functional outcome.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study is a post hoc analysis of the Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial, a double-blind, randomized, placebo-controlled, international, multicenter trial conducted from March 2017 to August 2019. Patients who participated in ESCAPE-NA1 and had available 90-day modified Rankin Scale (mRS) scores and 24-hour to 48-hour posttreatment follow-up parenchymal imaging were included.

EXPOSURES

Small FIV (volume ≤25th percentile) and large FIV (volume ≥75th percentile) on 24-hour computed tomography/magnetic resonance imaging. Baseline factors, outcomes, treatments, and poststroke serious adverse events (SAEs) were compared between discrepant cases (ie, patients with 90-day mRS score ≥3 despite small FIV or those with mRS scores ≤2 despite large FIV) and nondiscrepant cases.

MAIN OUTCOMES AND MEASURES

Area under the curve (AUC) and goodness of fit of prespecified logistic models, including pretreatment (eg, age, cancer, vascular risk factors) and treatment-related and posttreatment (eg, SAEs) factors, were compared with stepwise regression-derived models for ability to identify small FIV with higher mRS score and large FIV with lower mRS score.

RESULTS

Among 1091 patients (median [IQR] age, 70.8 [60.8-79.8] years; 549 [49.7%] women; median [IQR] FIV, 24.9 mL [6.6-92.2 mL]), 42 of 287 patients (14.6%) with FIV of 7 mL or less (ie, ≤25th percentile) had an mRS score of at least 3; 65 of 275 patients (23.6%) with FIV of 92 mL or greater (ie, ≥75th percentile) had an mRS score of 2 or less. Prespecified models of pretreatment factors (ie, age, cancer, vascular risk factors) associated with low FIV and higher mRS score performed similarly to models selected by stepwise regression (AUC, 0.92 [95% CI, 0.89-0.95] vs 0.93 [95% CI, 0.90-0.95]; P = .42). SAEs, specifically infarct in new territory, recurrent stroke, pneumonia, and congestive heart failure, were associated with low FIV and higher mRS scores; stepwise models also identified 24-hour hemoglobin as treatment-related/posttreatment factor (AUC, 0.92 [95% CI, 0.90-0.95] vs 0.94 [95% CI, 0.91-0.96]; P = .14). Younger age was associated with high FIV and lower mRS score; stepwise models identified absence of diabetes and higher baseline hemoglobin as additional pretreatment factors (AUC, 0.76 [95% CI, 0.70-0.82] vs 0.77 [95% CI, 0.71-0.83]; P = .82). Absence of SAEs, especially stroke progression, symptomatic intracerebral hemorrhage, and pneumonia, was associated with high FIV and lower mRS score2; stepwise models also identified 24-hour hemoglobin level, glucose, and diastolic blood pressure as posttreatment factors associated with discrepant cases (AUC, 0.80 [95% CI, 0.74-0.87] vs 0.79 [95% CI, 0.72-0.86]; P = .92).

CONCLUSIONS AND RELEVANCE

In this study, discrepancies between functional outcome and post-EVT infarct volume were associated with differences in pretreatment factors, such as age and comorbidities, and posttreatment complications related to index stroke evolution, secondary prevention, and quality of stroke unit care. Besides preventing such complications, optimization of blood pressure, glucose levels, and hemoglobin levels are potentially modifiable factors meriting further study.

Transcirculation Embolization to New Territory During Mechanical Thrombectomy for Acute Ischemic Stroke

Embolization in new territories (ENT) is a known complication of mechanical thrombectomy with incidence dependent upon a variety of procedural factors. We present 2 cases of anterior circulation to posterior circulation ENT. These cases were managed with manual aspiration thrombectomy with excellent radiographic and clinical outcome. We present the available literature involving ENT along with our experience in management.

Influence of prior intravenous thrombolysis on outcome after failed mechanical thrombectomy: ETIS registry analysis

BACKGROUND

Despite constant improvements in recent years, sufficient reperfusion after mechanical thrombectomy (MT) is not reached in up to 15% of patients with large vessel occlusion stroke (LVOS). The outcome of patients with unsuccessful reperfusion after MT especially after intravenous thrombolysis (IVT) use is not known. We investigated the influence of initial IVT in this particular group of patients with failed intracranial recanalization.

METHODS

We conducted a retrospective analysis of the Endovascular Treatment in Ischemic Stroke (ETIS) registry from January 2015 to December 2019. Patients presenting with LVOS of the anterior circulation and final modified Thrombolysis in Cerebral Infarction score (mTICI) of 0, 1 or 2a were included. Posterior circulation, isolated cervical carotid occlusions and successful reperfusions (mTICI 2b, 2c or 3) were excluded. The primary endpoint was favorable outcome (modified Rankin Scale score of 0-2) after 3 months. Secondary endpoints were safety outcomes including mortality, any intracranial hemorrhage (ICH), parenchymal hematoma (PH) and symptomatic intracranial hemorrhage (sICH) rates.

RESULTS

Among 5076 patients with LVOS treated with MT, 524 patients with insufficient recanalization met inclusion criteria, of which 242 received IVT and 282 did not. Functional outcome was improved in the MT+IVT group compared with the MT alone group, although the difference did not reach statistical significance (23.0% vs 12.9%; adjusted OR=1.82; 95% CI 0.98 to 3.38; p=0.058). However, 3 month mRS shift analysis showed a significant benefit of IVT (adjusted OR=1.68; 95% CI 1.56 to 6.54). ICH and sICH rates were similar in both groups, although PH rate was higher in the MT+IVT group (adjusted OR=3.20; 95% CI 1.56 to 6.54).

CONCLUSIONS

Among patients with LVOS in the anterior circulation and unsuccessful MT, IVT was associated with improved functional outcome even after unsuccessful MT. Despite recent trials questioning the place of IVT in the LVOS reperfusion strategy, these findings emphasize a subgroup of patients still benefiting from IVT.

Thrombolytic strategies for ischemic stroke in the thrombectomy era

Twenty-five years ago, intravenous thrombolysis has revolutionized the care of patients with acute ischemic stroke. Since 2015, randomized clinical trials have demonstrated that mechanical thrombectomy improves functional outcome in stroke patients over intravenous thrombolysis alone. More recently, three randomized clinical trials have suggested that mechanical thrombectomy alone is noninferior to a combined strategy with both intravenous thrombolysis and mechanical thrombectomy. In the present review, we will present the last clinical and preclinical studies on the use of thrombolysis in stroke patients in the modern thrombectomy era. At the cost of a potential increased risk of hemorrhagic transformation, thrombolysis may promote arterial recanalization before thrombectomy, improve the rate of successful recanalization after thrombectomy, and restore microcirculation patency downstream of the main thrombus. Besides, new thrombolytic strategies targeting tissue-type plasminogen activator resistant thrombi are being developed, which could strengthen the beneficial effects of thrombolysis without carrying additional pro-hemorrhagic effects. For instance, tenecteplase has shown improved rate of recanalization compared with tissue-type plasminogen activator (alteplase). Beyond fibrinolysis, DNA- and von Willebrand factor-targeted thrombolytic strategies have shown promising results in experimental models of ischemic stroke. New combined strategies, improved thrombolytics, and dedicated clinical trials in selected patients are eagerly awaited to further improve functional outcome in stroke.

Impact of Repeated Clot Retrieval Attempts on Infarct Growth and Outcome After Ischemic Stroke

OBJECTIVE

To determine whether the association between increasing number of clot retrieval attempts (CRA) and unfavorable outcome is due to an increase in emboli to new territory (ENT) and greater infarct growth (IG) in successfully recanalized patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO).

METHODS

Data were extracted from 2 pooled multicentric prospective registries of consecutive patients with anterior AIS-LVO treated with mechanical thrombectomy (MT) between January 2016 and 2019. Patients with pretreatment and 24-hour posttreatment diffusion-weighted imaging (DWI) achieving successful recanalization, defined as expanded Thrombolysis in Cerebral Infarction Scale score of 2B, 2C, or 3, were included. ENT were assessed and IG was measured by voxel-based segmentation after DWI coregistration. Associations between number of CRA, ENT, IG, and 3-month outcome were analyzed.

RESULTS

Four hundred nineteen patients achieving successful recanalization were included. ENT occurrence was strongly correlated with increasing CRA (ρ = 0.73, p = 10^-4). In multivariable linear analysis, IG was independently associated with CRA (β = 1.6 per retrieval attempt, 95% confidence interval [CI] 0.97-9.74, p = 0.03) and ENT (β = 2.7 [95% CI 1.21-4.1], p = 0.03). Unfavorable functional outcome (3-month modified Rankin Scale score >2) increased with each additional CRA. IG was an independent predictor of unfavorable outcome (odds ratio 1.05 [95% CI 1.02-1.07] per 1-mL IG increase, p = 10^-4) in binary logistic regression analysis.

CONCLUSIONS

Increasing number of CRA in acute stroke is correlated with an increased ENT rate and increased IG volume, affecting functional outcome even when successful recanalization is achieved.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that, for patients with acute stroke undergoing successful recanalization, an increasing number of CRA is associated with poorer functional outcome.

Stroke thrombectomy complication management

Endovascular mechanical thrombectomy (EVT) is widely accepted as the first-line treatment for acute ischemic stroke in patients with large vessel occlusion. Being an invasive treatment, this method is associated with various preoperative, perioperative, and postoperative complications. These complications may influence peri-interventional morbidity and mortality and therefore treatment efficacy and clinical outcome. The aim of this review is to discuss the most common types of complications associated with EVT, the probable mechanisms of injury, and effective methods to manage and prevent complications.

Frequency, Determinants, and Outcomes of Emboli to Distal and New Territories Related to Mechanical Thrombectomy for Acute Ischemic Stroke

[Figure: see text].

Thrombolysis in Cerebral Infarction 2b Reperfusions: To Treat or to Stop?

In patients undergoing mechanical thrombectomy, achieving complete (Thrombolysis in Cerebral Infarction 3) rather than incomplete successful reperfusion (Thrombolysis in Cerebral Infarction 2b) is associated with better functional outcome. Despite technical improvements, incomplete reperfusion remains the final angiographic result in 40% of patients according to recent trials. As most incomplete reperfusions are caused by distal vessel occlusions, they are potentially amenable to rescue strategies. While observational data suggest a net benefit of up to 20% in functional independence of incomplete versus complete reperfusions, the net benefit of secondary improvement from Thrombolysis in Cerebral Infarction 2b to 3 reperfusion might differ due to lengthier procedures and delayed reperfusion. Current strategies to tackle distal vessel occlusions consist of distal (microcatheter) aspiration, small adjustable stent retrievers, and administration of intra-arterial thrombolytics. While there are promising reports evaluating those techniques, all available studies show relevant limitations in terms of selection bias, single-center design, or nonconsecutive patient inclusion. Besides an assessment of risks associated with rescue maneuvers, we advocate that the decision-making process should also include a consideration of potential outcomes if complete reperfusion would successfully be achieved. These include (1) a futile angiographic improvement (hypoperfused territory is already infarcted), (2) an unnecessary angiographic improvement (the patient would not have developed infarction if no rescue maneuver was performed), and (3) a successful rescue maneuver with clinical benefit. Currently there is paucity of data on how these scenarios can be predicted and the decision whether to treat or to stop in a patient with incomplete reperfusion involves many unknowns. To advance the status quo, we outline current knowledge gaps and avenues of potential research regarding this clinically important question.

Association of initial imaging modality and futile recanalization after thrombectomy

Objective

To test the hypothesis that selection by initial imaging modality (MRI vs CT) is associated with rate of futile recanalizations (FRs) after mechanical thrombectomy (MT), we assessed this association in a multicenter, retrospective observational registry (BEYOND-SWIFT [Registry for Evaluating Outcome of Acute Ischemic Stroke Patients Treated With Mechanical Thrombectomy], NCT03496064).

Methods

In 2,011 patients (49.7% female, median age 73 years [61–81]) included between 2009 and 2017, we performed univariate and multivariate analyses regarding the occurrence of FR. FRs were defined as 90-day modified Rankin Scale (mRS) score 4–6 despite successful recanalization in patients selected by MRI (n = 690) and CT (n = 1,321) with a sensitivity analysis considering only patients with mRS 5–6 as futile.

Results

MRI as compared to CT resulted in similar rates of subsequent MT (adjusted odds ratio [aOR] 1.048, 95% confidence interval [CI] 0.677–1.624). Rates of FR were as follows: 571/1,489 (38%) FR mRS 4–6 including 393/1,489 (26%) FR mRS 5–6. CT-based selection was associated with increased rates of FRs compared to MRI (44% [41%–47%] vs 29% [25%–32%], p < 0.001; aOR 1.77 [95% CI 1.25–2.51]). These findings were robust in sensitivity analysis. MRI-selected patients had a delay of approximately 30 minutes in workflow metrics in real-world university comprehensive stroke centers. However, functional outcome and mortality were more favorable in patients selected by MRI compared to patients selected with CT.

Conclusions

CT selection for MT was associated with an increased risk of FRs as compared to MRI selection. Efforts are needed to shorten workflow delays in MRI patients. Further research is needed to clarify the role of the initial imaging modality on FR occurrence and to develop a reliable FR prediction algorithm.

Prevalence and Outcomes of Medium Vessel Occlusions With Discrepant Infarct Patterns

BACKGROUND AND PURPOSE

The prognosis of medium vessel occlusions (MeVOs), that is, M2/3 middle cerebral artery, A2/3 anterior cerebral artery, and P2/3 posterior cerebral artery occlusions, is generally better compared with large vessel occlusions, since brain ischemia is less extensive. However, in some MeVO patients, infarcts are seen outside the territory of the occluded vessel (MeVO with discrepant infarcts). This study aims to determine the prevalence and clinical impact of discrepant infarct patterns in acute ischemic stroke due to MeVO.

METHODS

We pooled data of MeVO patients from INTERRSeCT (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography) and PRove-IT (Precise and Rapid Assessment of Collaterals Using Multi-Phase CTA in the Triage of Patients With Acute Ischemic Stroke for IA Therapy)-2 prospective cohort studies of patients with acute ischemic stroke. The combination of occlusion location on baseline computed tomography angiography and infarct location on follow-up computed tomography/magnetic resonance imaging was used to identify MeVOs with discrepant infarct patterns. Two definitions for discrepant infarcts were applied; one was more restrictive and purely based on infarct patterns of the basal ganglia, whereas the second one took cortical infarct patterns into account. Clinical outcomes of patients with versus without discrepant infarcts were summarized using descriptive statistics. Logistic regression was performed to obtain adjusted effect size estimates for the association of discrepant infarcts and good outcome, defined as a modified Rankin Scale score of 0 to 2, and excellent outcome (modified Rankin Scale score 0-1).

RESULTS

Two hundred sixty-two patients with MeVO were included in the analysis. The prevalence of discrepant infarcts was 39.7% (definition 1) and 21.0% (definition 2). Patients with discrepant infarcts were less likely to achieve good outcome (definition 1: adjusted odds ratio, 0.48 [95% CI, 0.25-0.91]; definition 2: adjusted odds ratio, 0.47 [95% CI, 0.22-0.99]). When definition 1 was applied, patients with discrepant infarcts were also less likely to achieve excellent outcome (definition 1: adjusted odds ratio, 0.55 [95% CI, 0.31-0.99]; definition 2: adjusted odds ratio, 0.62 [95% CI, 0.31-1.25]).

CONCLUSIONS

MeVO patients with discrepant infarcts are common, and they are associated with more severe deficits and poor outcomes.

Thrombectomy for Distal, Medium Vessel Occlusions: A Consensus Statement on Present Knowledge and Promising Directions

Endovascular thrombectomy (EVT) is well established as a highly effective treatment for acute ischemic stroke (AIS) due to proximal, large vessel occlusions (PLVOs). With iterative further advances in catheter technology, distal, medium vessel occlusions (DMVOs) are now emerging as a promising next potential EVT frontier. This consensus statement integrates recent epidemiological, anatomic, clinical, imaging, and therapeutic research on DMVO-AIS and provides a framework for further studies. DMVOs cause 25% to 40% of AISs, arising as primary thromboemboli and as unintended consequences of EVT performed for PLVOs, including emboli to new territories (ENTs) and emboli to distal territories (EDTs) within the initially compromised arterial field. The 6 distal medium arterial arbors (anterior cerebral artery [ACA], M2–M4 middle cerebral artery [MCA], posterior cerebral artery [PCA], posterior inferior cerebellar artery [PICA], anterior inferior cerebellar artery [AICA], and superior cerebellar artery [SCA]) typically have 25 anatomic segments and give rise to 34 distinct arterial branches nourishing highly differentiated, largely superficial cerebral neuroanatomical regions. DMVOs produce clinical syndromes that are highly heterogenous but frequently disabling. While intravenous fibrinolytics are more effective for distal than proximal occlusions, they fail to recanalize one-half to two-thirds of DMVOs. Early clinical series using recently available, smaller, more navigable stent retriever and thromboaspiration devices suggest EVT for DMVOs is safe, technically efficacious, and potentially clinically beneficial. Collaborative investigations are desirable to enhance imaging recognition of DMVOs; advance device design and technical efficacy; conduct large registry studies using harmonized, common data elements; and complete formal randomized trials, improving treatment of this frequent mechanism of stroke.

Discrepancy between post-treatment infarct volume and 90-day outcome in the ESCAPE randomized controlled trial

BACKGROUND

Some patients with ischemic stroke have poor outcomes despite small infarcts after endovascular thrombectomy, while others with large infarcts sometimes fare better.

AIMS

We explored factors associated with such discrepancies between post-treatment infarct volume (PIV) and functional outcome.

METHODS

We identified patients with small PIV (volume ≤ 25th percentile) and large PIV (volume ≥ 75th percentile) on 24-48-h CT/MRI in the ESCAPE randomized-controlled trial. Demographics, comorbidities, baseline, and 24-48-h stroke severity (NIHSS), stroke location, treatment type, post-stroke complications, and other outcome scales like Barthel Index, and EQ-5D were compared between "discrepant cases" - those with 90-day modified Rankin Scale(mRS) ≤ 2 despite large PIV or mRS ≥ 3 despite small PIV - and "non-discrepant cases". Multi-variable logistic regression was used to identify pre-treatment and post-treatment factors associated with small-PIV/mRS ≥ 3 and large-PIV/mRS ≤ 2. Sensitivity analyses used different definitions of small/large PIV and good/poor outcome.

RESULTS

Among 315 patients, median PIV was 21 mL; 27/79 (34.2%) patients with PIV ≤ 7 mL (25th percentile) had mRS ≥ 3; 12/80 (15.0%) with PIV ≥ 72 mL (75th percentile) had mRS ≤ 2. Discrepant cases did not differ by CT versus MRI-based PIV ascertainment, or right versus left-hemisphere involvement (p = 0.39, p = 0.81, respectively, for PIV ≤ 7 mL/mRS ≥ 3). Pre-treatment factors independently associated with small-PIV/mRS ≥ 3 included older age (p = 0.010), cancer, and vascular risk-factors; post-treatment factors included 48-h NIHSS (p = 0.007) and post-stroke complications (p = 0.026). Absence of vascular risk-factors (p = 0.004), CT-based lentiform nucleus sparing (p = 0.002), lower 24-hour NIHSS (p = 0.001), and absence of complications (p = 0.013) were associated with large-PIV/mRS ≤ 2. Sensitivity analyses yielded similar results.

CONCLUSIONS

Discrepancies between functional ability and PIV are likely explained by differences in age, comorbidities, and post-stroke complications, emphasizing the need for high-quality post-thrombectomy stroke care.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT01778335.

Infarct in new territory after endovascular stroke treatment: A diffusion-weighted imaging study

Data on infarcts in new territory (INT) in patients undergoing endovascular stroke treatment for acute large-vessel occlusions are sparse. Aim of this study was to assess the prevalence, risk factors, and clinical relevance of INT. For this purpose, all patients in a single-center prospective registry who underwent endovascular stroke treatment and received pre- and post-interventional diffusion-weighted imaging were included (N = 259). Using an established scoring system, INT were classified according to size (I-III, ≤2 mm, >2 mm ≤20 mm, >20 mm) and likelihood of being related to the intervention (A, high likelihood; B, low likelihood). Additionally, a new type of infarct, that occurred in a territory distal to the occlusion, but was initially not hypoperfused, was defined as an infarct in initially not hypoperfused territory (IINHT). A total of 180 INT and 38 IINHT were observed in 32.8% (N = 85/259) of patients. In most patients, INT were angiographically occult (90.2%), and 13 patients had INT/IINHT larger than 2 cm (type III). Absence of protection during stent-retrieval and a cardio-embolic stroke origin were associated with higher incidence of INT/IINHT, whereas pretreatment with IV tPA showed no association, even when different bolus timing was considered. INT/IINHT were associated with lower rates of functional independence with increasing size type after adjusting for confounders (adjusted Odds Ratio per size group increase 0.63, 95% confidence interval 0.46-0.86). In conclusion, INT and IINHT are not rare, are associated with poor outcome with increasing size, and they may serve as a surrogate endpoint for safety evaluation of new devices and endovascular techniques. Further research on associated factors is warranted.

Displaying Multiphase CT Angiography Using a Time-Variant Color Map: Practical Considerations and Potential Applications in Patients with Acute Stroke

Various imaging protocols exist for the identification of vessel occlusion and assessment of collateral flow in acute stroke. CT perfusion is particularly popular because the color maps are a striking visual indicator of pathology. Multiphase CTA has similar diagnostic and prognostic ability but requires more expertise to interpret. This article presents a new multiphase CTA display format that incorporates vascular information from all phases of the multiphase CTA series in a single time-variant color map, thereby facilitating multiphase CTA interpretation, particularly for less experienced readers. Exemplary cases of multiphase CTA from this new display format are compared with conventional multiphase CTA, CT perfusion, and follow-up imaging to demonstrate how time-variant multiphase CTA color maps facilitate assessment of collateral flow, detection of distal and multiple intracranial occlusions, differentiation of pseudo-occlusion from real occlusion, and assessment of flow relevance of stenoses, ante- and retrograde flow patterns, and clot permeability.

Is intravenous thrombolysis still necessary in patients who undergo mechanical thrombectomy?

PURPOSE OF REVIEW

To summarize available evidence on the potential utility of pretreatment with intravenous thrombolysis (IVT) using recombinant tissue-plasminogen activator (rt-PA) in acute ischemic stroke (AIS) patients with large vessel occlusions (LVO) who are treated with mechanical thrombectomy.

RECENT FINDINGS

Despite theoretical concerns of a higher bleeding risk with IVT pretreatment, there are no data showing increased risk of symptomatic intracerebral hemorrhage (sICH) in patients with LVO receiving bridging therapy (IVT and mechanical thrombectomy) compared with direct mechanical thrombectomy (dMT). Additionally, evidence from observational studies suggest lower rates of infarctions in previously unaffected territories and higher rates of successful reperfusion, with lower number of device passes, in patients receiving bridging therapy. There are substantial discrepancies in studies comparing clinical outcomes between dMT and bridging therapy that are directly related to the inclusion of patients with contraindications to IVT in the dMT group. Ongoing clinical trials will provide definitive answers on the potential additional benefit of IVT in LVO patients receiving mechanical thrombectomy.

SUMMARY

IVT and mechanical thrombectomy are two effective reperfusion therapies that should be used in a swift and noncompeting fashion in AIS patients. AIS patients with LVO and no contraindications for IVT should receive promptly rt-PA bolus followed by immediate initiation of mechanical thrombectomy as indicated by current international recommendations, unless future randomized controlled trials provide evidence to proceed differently.

Intravenous thrombolysis pretreatment and other predictors of infarct in a new previously unaffected territory (INT) in ELVO strokes treated with mechanical thrombectomy

INTRODUCTION

One uncommon complication of mechanical thrombectomy (MT) is an infarct in a new previously unaffected territory (infarct in new territory (INT)).

OBJECTIVE

To evaluate the predictors of INT with special focus on intravenous thrombolysis(IVT)pretreatmentbefore MT.

METHODS

Consecutive patients with emergent large vessel occlusion (ELVO) treated with MT during a 5-year period were evaluated. INT was defined using standardized methodology proposed by ESCAPE investigators. The predictors of INT and its impact on outcomes were investigated.

RESULTS

A total of 419 consecutive patients with ELVO received MT (mean age 64±15 years, 50% men, median baseline National Institutes of Health Stroke Scale score 16 points (IQR 11-20), 69% pretreated with IVT). The incidence of INT was lower in patients treated with combination therapy (IVTandMT) than in patients treated with MT alone, respectively (10% vs 20%; p=0.011). The INT group had more patients with posterior circulation occlusions than the group without INT (28% vs 10%, respectively; p<0.001). The rates of 3-month functional independence were lower in patients with INT (30% vs 50%; p=0.007). IVT pretreatment was not independently related to INT (OR=0.75; 95% CI 0.32 to 1.76), and INT did not emerge as an independent predictor of 3-month functional independence (OR=0.69; 95% CI 0.29 to 1.62) on multivariable logistic regression models. Location of posterior circulation occlusion was independently associated with a higher odds of INT (OR=3.33; 95% CI 1.43 to 7.69; p=0.005).

CONCLUSIONS

IVT pretreatment is not independently associated with a lower likelihood of INT in patients with ELVO treated with MT. Patients with ELVO with posterior circulation occlusion are more likely to have INT after MT.

Endovascular treatment of acute ischaemic stroke in octogenarians and nonagenarians compared with younger patients

Purpose: Endovascular therapy for emergent large vessel occlusion has been established as the standard approach for acute ischaemic stroke. However, the effectiveness and safety of endovascular therapy in the very elderly population has not been proved. Objective: To determine the safety and effectiveness of endovascular therapy in octogenarians and nonagenarians. Methods: We retrospectively reviewed all patients who underwent endovascular therapy at two stroke centres between April 2012 and July 2018. Functional outcome was assessed using the modified Rankin scale at 90 days after stroke or at discharge. A favourable outcome was defined as a modified Rankin scale score of 0-2 or not worsening of the modified Rankin scale score before stroke. Outcome was compared between younger patients (aged 46-79 years, n = 40) and octogenarians and nonagenarians (aged 80-97 years, n = 19). Results: Octogenarian and nonagenarian patients had pre-stroke functional deficit (modified Rankin scale score >1) more frequently than younger patients (57.9% vs. 20.0%, respectively, P = 0.0059). No difference was observed between very elderly and younger patients in the rate of successful reperfusion (89.5% vs. 67.5%, respectively, P = 0.11), favourable functional outcome (47.4% vs. 45.0%, respectively, P = 1.00) and mortality (21.1% vs. 27.5%, respectively, P = 1.00). On multiple regression analysis, successful reperfusion, concomitant use of intravenous thrombolysis, and out-of-hospital onset were independent predictors of favourable outcome (P = 0.0003, 0.015 and 0.028, respectively). Conclusions: Successful reperfusion, concomitant use of intravenous thrombolysis, and out-of-hospital onset were clinical predictors of favourable outcome. However, we did not observe an age-dependent effect of clinical outcome after endovascular therapy.

Clinical effect of successful reperfusion in patients presenting with NIHSS < 8: data from the BEYOND-SWIFT registry

BACKGROUND AND PURPOSE

If patients presenting with large vessel occlusions (LVO) and mild symptoms should be treated with endvoascular treatment (EVT) remains unclear. Aims of this study were (1) assessing the safety and technical efficacy of EVT in patients with NIHSS < 8 as opposed to a comparison group of patients presenting with NIHSS ≥ 8 and (2) evaluation of the clinical effect of reperfusion in patients with NIHSS < 8.

METHODS

Patients included into the retrospective multicenter BEYOND-SWIFT registry (NCT03496064) were analyzed. Clinical effect of achieving successful reperfusion (defined as modified Thrombolysis in Cerebral Infarction grade 2b/3) in patients presenting with NIHSS < 8 (N = 193) was evaluated using multivariable logistic regression analyses (displayed as adjusted Odds Ratios, aOR and 95% confidence intervals, 95%-CI). Primary outcome was excellent functional outcome (modified Rankin Scale, mRS 0-1) at day 90. Safety and efficacy of mechanical thrombectomy in patients with NIHSS < 8 was compared to patients presenting with NIHSS ≥ 8 (N = 1423).

RESULTS

Among patients with NIHSS < 8 (N = 193, 77/193, 39.9% receiving pre-interventional IV-tPA), successful reperfusion was significantly related to mRS 0-1 (aOR 3.217, 95%-CI 1.174-8.816) and reduced the chances of non-hemorrhagic neurological worsening (aOR 0.194, 95%-CI 0.050-0.756) after adjusting for prespecified confounders. In interaction analyses, the relative merits of achieving successful reperfusion were mostly comparable between patients presenting with NIHSS < 8 and NIHSS ≥ 8 as evidenced by non-significantly different aOR. Interventional safety and efficacy metrics were similar between patients with NIHSS < 8 and NIHSS ≥ 8.

CONCLUSIONS

Achieving successful reperfusion is beneficial in patients with persisting LVO presenting with NIHSS < 8 and reduces the risk of non-hemorrhagic neurological worsening.

Post-Thrombolysis Recanalization in Stroke Referrals for Thrombectomy

Background and Purpose—

Whether all acute stroke patients with large vessel occlusion need to undergo intravenous thrombolysis before mechanical thrombectomy (MT) is debated as (1) the incidence of post-thrombolysis early recanalization (ER) is still unclear; (2) thrombolysis may be harmful in patients unlikely to recanalize; and, conversely, (3) transfer for MT may be unnecessary in patients highly likely to recanalize. Here, we determined the incidence and predictors of post-thrombolysis ER in patients referred for MT and derive ER prediction scores for trial design.

Methods—

Registries from 4 MT-capable centers gathering patients referred for MT and thrombolyzed either on site (mothership) or in a non MT-capable center (drip-and-ship) after magnetic resonance– or computed tomography–based imaging between 2015 and 2017. ER was identified on either first angiographic run or noninvasive imaging. In the magnetic resonance imaging subsample, thrombus length was determined on T2*-based susceptibility vessel sign. Independent predictors of no-ER were identified using multivariable logistic regression models, and scores were developed according to the magnitude of regression coefficients. Similar registries from 4 additional MT-capable centers were used as validation cohort.

Results—

In the derivation cohort (N=633), ER incidence was ≈20%. In patients with susceptibility vessel sign (n=498), no-ER was independently predicted by long thrombus, proximal occlusion, and mothership paradigm. A 6-point score derived from these variables showed strong discriminative power for no-ER (C statistic, 0.854) and was replicated in the validation cohort (n=353; C statistic, 0.888). A second score derived from the whole sample (including negative T2* or computed tomography–based imaging) also showed good discriminative power and was similarly validated. Highest grades on both scores predicted no-ER with >90% specificity, whereas low grades did not reliably predict ER.

Conclusions—

The substantial ER rate underlines the benefits derived from thrombolysis in bridging populations. Both prediction scores afforded high specificity for no-ER, but not for ER, which has implications for trial design.

Further Development of Combined Techniques Using Stent Retrievers, Aspiration Catheters and BGC : The PROTECTPLUS Technique

PURPOSE

First pass complete (mTICI 3) reperfusion must be regarded as the ultimate goal in mechanical thrombectomy (MT) in patients suffering from an emergent large vessel occlusion (ELVO). With this in mind a technical modification of the previously published PROTECT (PRoximal balloon Occlusion TogEther with direCt Thrombus aspiration during stent retriever thrombectomy) approach, the PROTECT^PLUS technique was evaluated. Under proximal flow arrest using a balloon guide catheter (BGC), a stent retriever was only partially inserted into a large-bore aspiration catheter. This construction was subsequently retracted as a unit into the BGC with aspiration both at the aspiration catheter and at the BGC.

METHODS

A case-control study was performed comparing the PROTECT technique with the PROTECT^PLUS technique with respect to the technical and procedural parameters. Patients n = 165 (101 PROTECT, 64 PROTECT^PLUS) with ELVO of either the terminus of the internal carotid artery or the proximal middle cerebral artery were included.

RESULTS

Using the PROTECT^PLUS resulted in a higher rate of first pass complete reperfusions (59.4% vs. 27.7%, p < 0.001) as compared with PROTECT. The PROTECT^PLUS also led to shorter procedure times (21 min vs. 37 min, p = 0.001) and higher rates of overall complete reperfusion (73.5% vs. 49.5%, p = 0.014) compared to PROTECT.

CONCLUSION

The PROTECT^PLUS technique is a promising technical modification to further optimize endovascular stroke treatment.

Mechanical Thrombectomy Outcomes With or Without Intravenous Thrombolysis

Background and Purpose—

Intravenous thrombolysis (IVT) within 4.5 hours of symptom onset is currently recommended before mechanical thrombectomy (MT). We compared functional outcome, neurological recovery, reperfusion, and adverse events according to the use or not of IVT before MT.

Methods—

This is a post hoc analysis of the ASTER trial (Contact Aspiration Versus Stent Retriever for Successful Revascularization). The primary outcome was favorable 90-day functional outcome defined as a modified Rankin Scale of ≤2. Secondary outcomes were successful reperfusion following all procedures and after the first-line procedure, number of device passes, and change in National Institutes of Health Stroke Scale score at 24 hours. Safety outcomes included 90-day mortality and any symptomatic intracerebral hemorrhage.

Results—

Three hundred eighty-one patients were included, 250 of whom received IVT before MT (IVT+MT group). There were no significant differences between IVT+MT and MT-alone groups in 90-day favorable functional outcome, in successful reperfusion rate (modified Thrombolysis In Cerebral Infarction 2b or 3), in National Institutes of Health Stroke Scale score improvement at 24 hours, or in hemorrhagic complication rate. The 90-day mortality rate in the IVT+MT group was lower than after MT alone (fully-adjusted risk ratio, 0.59; 95% CI, 0.39–0.88). In a subgroup of patients without anticoagulant medication before stroke onset, we observed in the IVT+MT group a better functional outcome (fully-adjusted risk ratio, 1.38; 95% CI, 1.02–1.89), a higher successful recanalization rate after first-line strategy (fully-adjusted risk ratio, 1.26; 95% CI, 1.05–1.50), and a lower mortality rate (fully-adjusted risk ratio, 0.58; 95% CI, 0.36–0.93).

Conclusions—

Our results show that IVT+MT patients in the ASTER trial have lower 90-day mortality compared with those receiving MT alone. In a selected population of patients without prestroke anticoagulation, we demonstrated that IVT associated with MT might improve functional outcome and recanalization while reducing mortality rates.

Intravenous Thrombolysis Prior to Mechanical Thrombectomy in Acute Ischemic Stroke: Silver Bullet or Useless Bystander?

BACKGROUND AND PURPOSE

Recent single-center series and meta-analyses suggest that mechanical thrombectomy (MT) without prior intravenous thrombolysis (IVT) might be equally effective to bridging therapy. We analyzed, within the Endovascular Treatment in Ischemic Stroke (ETIS) prospective observational registry, the angiographic and clinical outcomes after IVT+MT versus MT alone.

METHODS

From December 2012 to December 2016, a total of 1,507 consecutive patients with a proximal arterial occlusion of the anterior circulation were treated by MT. Of these, 975 (64.7%) received prior IVT. Immediate angiographic and clinical outcomes at 90 days (modified Rankin Scale [mRS]) were compared between the two groups while checking for propensity score, matched-propensity score and by inverse probability of treatment weighting (IPTW) propensity score method.

RESULTS

Favorable outcome (mRS 0 to 2) was more frequently achieved after IVT+MT (n=523, 53.6%) than after MT alone (n=222, 41.8%) with an unadjusted odds ratio (OR) for bridging therapy of 1.61 (95% confidence interval [CI], 1. 29 to 2.01). This difference remained not significant in matched-propensity score cohort (OR, 1.21; 95% CI, 0.90 to 1.63) although it remained according to adjusted propensity score (OR, 1.31; 95% CI, 1.02 to 1.68) and IPTW (OR, 1.37; 95% CI, 1.09 to 1.73) analyses. A significant difference was found in terms of excellent outcome (mRS 0 to 1) (adjusted OR, 1.63; 95% CI, 1.25 to 2.11) and successful reperfusion (adjusted OR, 1.58; 95% CI, 1.33 to 2.15). No differences in intracerebral hemorrhage or in allcause mortality within 90 days were found between groups.

CONCLUSION

s IVT prior to MT is associated with increased excellent outcome and successful reperfusion rates. These findings support the use of bridging therapy.

Thrombectomy for Acute Ischemic Stroke: Recent Insights and Future Directions

PURPOSE OF REVIEW

Mechanical thrombectomy has become the standard of care for acute ischemic stroke with proximal large vessel occlusions (LVO). This article reviews recent research relating to thrombectomy.

RECENT FINDINGS

Thrombectomy for anterior circulation stroke with proximal LVO was first shown to be highly efficacious within 6 h of stroke onset, but "late-window" trials have further demonstrated efficacy until 24-h postonset in select patients with salvageable tissue. However, the concept of "time is brain" remains critical. Thrombectomy trials have further stimulated worldwide efforts to develop systems of care for rapid treatment of eligible patients. Thrombectomy is cost-effective and likely to have long-term efficacy for both disability and mortality outcomes. Thrombectomy is a highly efficacious acute stroke therapy. Enduring uncertainties include efficacy in patients with premorbid disability, posterior circulation, or more distal occlusions; use of bridging thrombolysis; and optimal techniques to achieve consistent revascularization and address tandem occlusions or stenoses.

Intravenous thrombolysis for acute ischemic stroke: a bridge between two centuries

INTRODUCTION

Intravenous tissue-plasminogen activator (tPA) remains the only approved systemic reperfusion therapy suitable for most patients presenting timely with acute ischemic stroke. Accumulating real-word experience for over 20 years regarding tPA safety and effectiveness led to re-appraisal of original contraindications for intravenous thrombolysis (IVT). Areas covered: This narrative review focuses on fast yet appropriate selection of patients for safe administration of tPA per recently expanded indications. Novel strategies for rapid patient assessment will be discussed. The potential for mobile stroke units (MSU) that shorten onset-to-needle time and increase tPA treatment rates is addressed. The use of IVT in the era of non-vitamin K antagonist oral anticoagulants (NOACs) is highlighted. The continuing role of IVT in large vessel occlusion (LVO) patients eligible for mechanical thrombectomy (MT) is discussed with regards to 'drip and ship' vs. 'mothership' treatment paradigms. Promising studies of penumbral imaging to extend IVT beyond the 4.5-hour window and in wake-up strokes are summarized. Expert commentary: This review provides an update on the role of IVT in specific conditions originally considered tPA contraindications. Novel practice challenges including NOAC's, MSU proliferation and bridging therapy (IVT&MT) for LVO patients, and the potential extension of IVT time-window using penumbral imaging are emerging as safe and potentially effective IVT applications.

Anterior cerebral artery embolism during thrombectomy increases disability and mortality

Objective

During thrombectomy, thromboembolic migration in previously unaffected territory may occur and is not systematically notified. We report our data on the incidence, predictors, and clinical outcome of anterior cerebral artery emboli (ACAE).

Methods

From a prospectively collected thrombectomy database of consecutive patients with anterior circulation stroke between January 2012 and December 2016, 690 angiographic images were analyzed to assess ACAE. The primary outcome was a favorable outcome, defined as a 3 month modified Rankin Scale score of 0–2 or equal to the pre-stroke score.

Results

ACAE occurred in 65 patients (9.4%; 95% CI 7.2% to 11.6%). Internal carotid artery occlusion (tandem or terminal), Alberta Stroke Program Early CT Score <7, increasing number of passes, and use of stent retriever alone (compared with distal aspiration alone or combined with stent retriever) were found to be independent predictors of ACAE. Compared with patients without ACAE, patients with ACAE had lower rates, with an adjusted OR (95% CI) of 0.48 (0.25 to 0.92; P=0.027) for favorable outcome and 0.49 (0.25 to 0.96; P=0.038) for early neurologic improvement. ACAE was significantly associated with a higher mortality (adjusted OR 1.93; 95% CI 1.03 to 3.61; P=0.039) and intracranial hemorrhagic complications (adjusted OR 2.45; 95% CI 1.33 to 4.47; P=0.004). Despite a successful reperfusion modified Thrombolysis in Cerebral Infarction score of 2b–3 at the end of the procedure, a favorable outcome was reached in 30% of patients with ACAE compared with 52.4% in the other patients (OR 0.39; 95% CI 0.19 to 0.78; P=0.008).

Conclusions

Procedural ACAE was not an uncommon condition, and was associated with increased mortality and disability rates, regardless of the success of reperfusion.

Comparative safety and efficacy of combined IVT and MT with direct MT in large vessel occlusion

OBJECTIVE

In this multicenter study, we sought to evaluate comparative safety and efficacy of combined IV thrombolysis (IVT) and mechanical thrombectomy (MT) vs direct MT in emergent large vessel occlusion (ELVO) patients.

METHODS

Consecutive ELVO patients treated with MT at 6 high-volume endovascular centers were evaluated. Standard safety and efficacy outcomes (successful reperfusion [modified Thrombolysis in Cerebral Infarction IIb/III], functional independence [FI] [modified Rankin Scale (mRS) score of 0-2 at 3 months], favorable functional outcome [mRS of 0-1 at 3 months], functional improvement [mRS shift by 1-point decrease in mRS score]) were compared between patients who underwent combined IVT and MT vs MT alone. Additional propensity score-matched analyses were performed.

RESULTS

A total of 292 and 277 patients were treated with combination therapy and direct MT, respectively. The combination therapy group had greater functional improvement (p = 0.037) at 3 months. After propensity score matching, 104 patients in the direct MT group were matched to 208 patients in the combination therapy group. IVT pretreatment was independently (p < 0.05) associated with higher odds of FI (odds ratio [OR] 1.75; 95% confidence interval [CI] 1.02-2.99) and functional improvement (common OR 1.64; 95% CI 1.05-2.56). Combination therapy was independently (p < 0.05) related to lower likelihood of 3-month mortality (0.50; 95% CI 0.26-0.96).

CONCLUSIONS

This observational study provides preliminary evidence that IVT pretreatment may improve outcomes in ELVO patients treated with MT. The question of the potential effect of IVT on ELVO patients treated with MT should be addressed with a randomized controlled trial.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that for stroke patients with emergent large vessel occlusion, combined IVT and MT is superior to direct MT in improving functional outcomes.

Complications of endovascular treatment for acute ischemic stroke: Prevention and management

Endovascular mechanical thrombectomy (MT) for the treatment of acute stroke due to large vessel occlusion has evolved significantly with the publication of multiple positive thrombectomy trials. MT is now a recommended treatment for acute ischemic stroke. Mechanical thrombectomy is associated with a number of intra-procedural or post-operative complications, which need to be minimized and effectively managed to maximize the benefits of thrombectomy. Procedural complications include: access-site problems (vessel/nerve injury, access-site hematoma and groin infection); device-related complications (vasospasm, arterial perforation and dissection, device detachment/misplacement); symptomatic intracerebral hemorrhage; subarachnoid hemorrhage; embolization to new or target vessel territory. Other complications include: anesthetic/contrast-related, post-operative hemorrhage, extra-cranial hemorrhage and pseudoaneurysm. Some complications are life-threatening and many lead to increased length of stay in intensive care and stroke units. Complications increase costs and delay the commencement of rehabilitation. Some may be preventable; the impact of others can be minimized with early detection and appropriate management. Both neurointerventionists and stroke specialists need to be aware of the risk factors, strategies for prevention, and management of these complications. With the increasing use of mechanical thrombectomy for the treatment of acute ischemic stroke, incidence and outcome of complications will need to be carefully monitored by stroke teams. In this narrative review, we examine the frequency of complications of MT in the treatment of acute ischemic stroke with an emphasis on periprocedural complications. Overall, from recent randomized controlled trials, the risk of complications with sequelae for patient from mechanical thrombectomy is ∼15%. We discuss the management of complications and identify areas with limited evidence, which need further research. Search strategy and selection criteria Relevant evidence was found by searches of Medline and Cochrane Library, reference list, cross-referencing and main journal content pages. Search terms included "brain ischemia", "acute ischemic stroke", "cerebral infarction" AND "mechanical thrombectomy", "endovascular therapy", "endovascular treatment", "endovascular embolectomy", "intra-arterial" AND "randomized controlled trial", "non-randomised trials", "observational studies" AND "complications", "procedural complications", "peri-procedural complications", "device-related complications", "management", "treatment", "outcome". The search included only human studies, and was limited to studies published in English between January 2014 and November 2016. The final reference list was selected on the basis of relevance to the topics covered in the Review. Guidelines for management of acute ischaemic stroke by the American Heart Association, the European Stroke Organisation, multi-disciplinary guidelines and the National Institute for Health and Care Excellence (NICE) were also reviewed.

Assessing the efficacy of endovascular therapy in stroke treatments: updates from the new generation of trials

INTRODUCTION

For the past 20 years, intravenous recombinant tissue plasminogen activator (rt-PA) has been the only proven treatment for acute ischemic stroke. Large arteries such as the internal carotid artery, the middle cerebral artery and the basilar artery supply blood to large volumes of brain tissue. When occluded, these vessels may have low response rates to rt-PA resulting in devastating injury and death. Areas covered: In 2013, three trials evaluating the efficacy of mechanical thrombectomy in acute stroke were neutral, however, lessons learned from these trials resulted in a second generation of five trials in 2015 and a sixth in 2016 which all demonstrated significant benefit for select patients. Here we will review the evidence behind these new trials and. introduce new questions such as models of care, techniques of thrombectomy, the role of rt-PA, modes of anesthesia, the management of late presenting and wake up strokes among other real world challenges facing stroke medicine now that the thrombectomy is an evidence based treamtnent Expert commentary: The mechanical thrombectomy is now the new standard of care and with that comes the need to find ways to provide it to all who will benefit.

Randomized, Multicenter Trial of ARTSS-2 (Argatroban With Recombinant Tissue Plasminogen Activator for Acute Stroke)

BACKGROUND AND PURPOSE

We conducted a randomized exploratory study to assess safety and the probability of a favorable outcome with adjunctive argatroban, a direct thrombin-inhibitor, administered to recombinant tissue-type plasminogen activator (r-tPA)-treated ischemic stroke patients.

METHODS

Patients treated with standard-dose r-tPA, not receiving endovascular therapy, were randomized to receive no argatroban or argatroban (100 μg/kg bolus) followed by infusion of either 1 (low dose) or 3 μg/kg per minute (high dose) for 48 hours. Safety was incidence of symptomatic intracerebral hemorrhage. Probability of clinical benefit (modified Rankin Scale score 0-1 at 90 days) was estimated using a conservative Bayesian Poisson model (neutral prior probability centered at relative risk, 1.0 and 95% prior intervals, 0.33-3.0).

RESULTS

Ninety patients were randomized: 29 to r-tPA alone, 30 to r-tPA+low-dose argatroban, and 31 to r-tPA+high-dose argatroban. Rates of symptomatic intracerebral hemorrhage were similar among control, low-dose, and high-dose arms: 3/29 (10%), 4/30 (13%), and 2/31 (7%), respectively. At 90 days, 6 (21%) r-tPA alone, 9 (30%) low-dose, and 10 (32%) high-dose patients were with modified Rankin Scale score 0 to 1. The relative risks (95% credible interval) for modified Rankin Scale score 0 to 1 with low, high, and either low or high dose argatroban were 1.17 (0.57-2.37), 1.27 (0.63-2.53), and 1.34 (0.68-2.76), respectively. The probability that adjunctive argatroban was superior to r-tPA alone was 67%, 74%, and 79% for low, high, and low or high dose, respectively.

CONCLUSIONS

In patients treated with r-tPA, adjunctive argatroban was not associated with increased risk of symptomatic intracerebral hemorrhage and provides evidence that a definitive effectiveness trial is indicated.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01464788.