Mechanical Thrombectomy for Large Ischemic Stroke: A Systematic Review and Meta-analysis

Evaluating high-flow oxygen therapy after mechanical thrombectomy under general anesthesia in acute ischemic stroke: A retrospective single-center study

BACKGROUND

The use of mechanical thrombectomy for acute intracranial vascular occlusion under general anesthesia with endotracheal intubation is well-established as a safe and effective method. However, the process of extubation post-surgery presents challenges for certain patients. This retrospective study assesses the safety and efficacy of combining mechanical ventilation with high-flow oxygen inhalation as an interim strategy, while also examining its impact on long-term clinical outcomes.

METHODS

This research enrolled 119 patients with acute intracranial large vessel occlusion who underwent mechanical thrombectomy under general anesthesia with tracheal intubation between January 2020 and November 2023. Participants were categorized into two groups: Group 1 (n=55), which received high-flow oxygen (HFO) post-extubation, and Group 2 (n=64), which was treated with routine oxygen supplementation (RO). The study compared reintubation and tracheotomy rates between these groups to determine safety and effectiveness. Additionally, it analyzed long-term clinical outcomes by comparing NIHSS and mRS scores before treatment and at 90-day follow-up.

RESULTS

The reintubation rate post-extubation was significantly lower in the HFO group (12.7 %, n=7) compared to the RO group (31.2 %, n=20, p=0.016). The incidence of tracheotomy within 7 days was also reduced in the HFO group compared to the RO group (7.3 %, n=4 vs 20.3 %, n=13, p=0.043). Moreover, a greater proportion of patients in the HFO group achieved mRS scores of 0-2 at 90 days post-stroke than those in the RO group (60 %, n=33 vs 40.6 %, n=26, p=0.035). The median NIHSS score at 90 days was more favorable in the HFO group than in the RO group (6, IQR [1-18] vs 8, IQR [1-20], p=0.005).

CONCLUSION

The study suggests that high-flow oxygen therapy after mechanical thrombectomy under general anesthesia with tracheal intubation may lessen the need for reintubation and tracheotomy, potentially leading to improved long-term prognosis.

CLEAR Thrombectomy Score: An Index to Estimate the Probability of Good Functional Outcome With or Without Endovascular Treatment in the Late Window for Anterior Circulation Occlusion

BACKGROUND

With the expanding eligibility for endovascular therapy (EVT) of patients presenting in the late window (6-24 hours after last known well), we aimed to derive a score to predict favorable outcomes associated with EVT versus best medical management.

METHODS AND RESULTS

A multinational observational cohort of patients from the CLEAR (Computed Tomography for Late Endovascular Reperfusion) study with proximal intracranial occlusion (2014-2022) was queried (n=58 sites). Logistic regression analyses were used to derive a 9-point score for predicting good functional outcome (modified Rankin Scale score 0-2 or return to premorbid modified Rankin Scale score) at 90 days, with sensitivity analyses for prespecified subgroups conducted using bootstrapped random forest regressions. Secondary outcomes included 90-day functional independence (modified Rankin Scale score 0-2), poor outcome (modified Rankin Scale score 5-6), and 90-day survival. The score was externally validated with a single-center cohort (2014-2023). Of the 3231 included patients (n=2499 EVT), a 9-point score included age, early computed tomography ischemic changes, and stroke severity, with higher points indicating a higher probability of a good functional outcome. The areas under the curve for the primary outcome among EVT and best medical management subgroups were 0.72 (95% CI, 0.70-0.74) and 0.87 (95% CI, 0.84-0.90), respectively, with similar performance in the external validation cohort (area under the curve, 0.71 [95% CI, 0.66-0.76]). There was a significant interaction between the score and EVT for good functional outcome, functional independence, and poor outcome (all Pinteraction<0.001), with greater benefit favoring patients with lower and midrange scores.

CONCLUSIONS

This score is a pragmatic tool that can estimate the probability of a good outcome with EVT in the late window.

REGISTRATION

URL: https://www.Clinicaltrials.gov; Unique identifier: NCT04096248.

Endovascular thrombectomy for ischemic stroke with large infarct, short- and long-term outcomes: a meta-analysis of 6 randomised control trials

Endovascular Thrombectomy (EVT) as first-line treatment of patients with large core ischemic infarct is a subject of debate. A systematic literature search was conducted in four electronic databases for randomized control trials (RCTs) comparing EVT to best medical treatment (BMT) for large core infarcts (ASPECTS ≤ 5). Relevant studies were added after screening for titles, abstracts, and complete text. Meta-analysis was performed. The continuous outcomes were analyzed using the standardized mean difference (SMD) and 95% CI, while the binary outcomes were analyzed using the risk ratio (RR) and 95% confidence interval (CI). A funnel plot was used to visually evaluate publication bias, and if feasible, Egger's test was used to validate. We included 1918 patients from six RCTs that compared EVT plus BMT and BMT alone in patients with large core infarct due to large vessel occlusion in the anterior circulation. There were 946 patients in the EVT group and 972 patients in the BMT group. The one-year outcomes are available for 314 patients in the EVT group and 292 patents in the BMT group from two RCTs. EVT group had statistically significant higher rate of 90-day mRS 0-1 (RR = 3.1, P-value < 0.0001), mRS 0-2 (RR = 2.64, P-value < 0.0001), mRS 0-3 (RR = 1.80, P-value < 0.0001), lower 90-day mean mRS score (SMD = -0.29, P-value < 0.0001), lower 90-day mortality rate (RR = 0.85, P-value = 0.015), and greater early neurological improvement (RR = 2.16, P-value < 0.00001) compared to the BMT group. However, the rates of symptomatic intracerebral hemorrhage (sICH) (RR = 1.76, P-value = 0.01) and any ICH (RR = 2.18, P-value < 0.00001) were higher in EVT group. Our finding showed that EVT plus BMT led to in an absolute improvement of 5%, 12%, and 16% in 90-day mRS 0-1, 0-2, and 0-3, respectively. In addition, patients in EVT plus BMT group had a 3% increased probability of experiencing sICH and were 32% more susceptible to any ICH. Moreover, the one-year mRS 0-2 (RR = 2.16, P-value < 0.00001) and mRS 0-3 (RR = 1.80, P-value < 0.0001) was significantly favor the EVT plus BMT over BMT alone. Although, the one-year mortality rate was not significantly differed between two groups (RR = 0.91, P-value = 0.31). There was no statistically significant difference observed between the EVT plus BMT group and the BMT group concerning new stroke, decompressive craniectomy, and serious adverse events. Combined data from six RCTs shows that EVT plus BMT provides significantly better short- and long-term functional outcomes with minimal increase in symptomatic hemorrhage over BMT in patient with large core infarcts.

Cost-effectiveness of endovascular thrombectomy for acute ischemic stroke with established large infarct in Germany: a decision tree and Markov model

BACKGROUND

Recent studies, including the TENSION trial, support the use of endovascular thrombectomy (EVT) in acute ischemic stroke with large infarct (Alberta Stroke Program Early Computed Tomography Score (ASPECTS) 3-5).

OBJECTIVE

To evaluate the cost-effectiveness of EVT compared with best medical care (BMC) alone in this population from a German healthcare payer perspective.

METHODS

A short-term decision tree and a long-term Markov model (lifetime horizon) were used to compare healthcare costs and quality-adjusted life years (QALYs) between EVT and BMC. The effectiveness of EVT was reflected by the 90-day modified Rankin Scale (mRS) outcome from the TENSION trial. QALYs were based on published mRS-specific health utilities (EQ-5D-3L indices). Long-term healthcare costs were calculated based on insurance data. Costs (reported in 2022 euros) and QALYs were discounted by 3% annually. Cost-effectiveness was assessed using incremental cost-effectiveness ratios (ICERs). Deterministic and probabilistic sensitivity analyses were performed to account for parameter uncertainties.

RESULTS

Compared with BMC, EVT yielded higher lifetime incremental costs (€24 257) and effects (1.41 QALYs), resulting in an ICER of €17 158/QALY. The results were robust to parameter variation in sensitivity analyses (eg, 95% probability of cost-effectiveness was achieved at a willingness to pay of >€22 000/QALY). Subgroup analyses indicated that EVT was cost-effective for all ASPECTS subgroups.

CONCLUSIONS

EVT for acute ischemic stroke with established large infarct is likely to be cost-effective compared with BMC, assuming that an additional investment of €17 158/QALY is deemed acceptable by the healthcare payer.

Endovascular thrombectomy for acute ischemic stroke with a large infarct area: An updated systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Since the efficacy and safety of endovascular thrombectomy (EVT) in patients with acute ischemic stroke with a large infarct area is still inconclusive, we sought to compare functional and neurological outcomes with the use of endovascular thrombectomy versus medical care alone.

METHODS

We searched MEDLINE (via PubMed), Embase, Cochrane Library, ClinicalTrials.gov, and the International Clinical Trials Registry Platform (ICTRP) to retrieve all the relevant randomized controlled trials (RCTs) on this topic. Review manager (RevMan) was used to perform meta-analyses using a random-effect model. Dichotomous outcomes were pooled using risk ratios (RR) with 95% confidence intervals (CIs).

RESULTS

Our meta-analysis included 6 RCTs with a total of 1665 patients. Most studies included patients with an ASPECTS score of 3-5. Our results demonstrate that endovascular thrombectomy significantly increased the rates of functional independence (mRS ≤ 2) (RR, 2.49; 95% CI, 1.89-3.29) and moderate neurological outcome (mRS ≤ 3) (RR, 1.90; 95% CI, 1.50-2.40) at 90 days. The benefit of EVT for these outcomes remained the same at 1-year follow-up. Endovascular thrombectomy was associated with increased rates of early neurological improvement (RR, 2.22; 95% CI, 1.53-3.22), excellent neurological recovery (mRS ≤ 1) (RR, 1.75; 95% CI, 1.02-3.03), and decreased rate of poor neurological recovery (mRS 4-6) (RR, 0.81; 95% CI, 0.76-0.86). No significant difference was found between the two groups regarding all-cause mortality (RR, 0.86; 95% CI, 0.72-1.02), decompressive craniectomy (RR, 1.32; 95% CI, 0.89-1.94), and the incidence of serious adverse effects (RR, 1.39; 95% CI, 0.83-2.32) between the two groups. Endovascular thrombectomy significantly increased the rates of any intracranial hemorrhage (RR, 1.94; 95% CI, 1.48-2.53) and symptomatic intracranial hemorrhage (RR, 1.73; 95% CI, 1.11-2.69).

CONCLUSION

Endovascular thrombectomy (EVT) significantly improves neurological and functional outcomes in patients who present within 6 hours of stroke onset with ICA and proximal M1 occlusions, and ASPECTS scores ranging from 3 to 5, compared to medical therapy alone, with an increased risk of symptomatic intracranial hemorrhage.

Unsuccessful Recanalization versus Medical Management of Patients with Large Ischemic Core : Analysis of the ANGEL-ASPECT Randomized Trial

PURPOSE

The outcomes of patients with large ischemic core who fail to recanalize with endovascular therapy (EVT) compared to medical management (MM) are uncertain. The objective was to evaluate the clinical and safety outcomes of patients who underwent EVT in patients with large ischemic core and unsuccessful recanalization.

METHODS

This was a post hoc analysis of the ANGEL-ASPECT randomized trial. Unsuccessful recanalization was defined as patients who underwent EVT with eTICI 0-2a. The primary endpoint was 90-day very poor outcome (mRS 5-6). Multivariable logistic regression was conducted controlling for ASPECTS, occlusion location, intravenous thrombolysis, and time to treatment.

RESULTS

Of 455 patients 225 were treated with MM. Of 230 treated with EVT, 43 (19%) patients had unsuccessful recanalization. There was no difference in 90-day very poor outcomes (39.5% vs. 40%, aOR 0.93, 95% confidence interval, CI 0.47-1.85, p = 0.95), sICH (7.0% vs. 2.7%, aOR 2.81, 95% CI 0.6-13.29, p = 0.19), or mortality (30% vs. 20%, aOR 1.65, 95% CI 0.89-3.06, p = 0.11) between the unsuccessful EVT and MM groups, respectively. There were higher rates of ICH (55.8% vs. 17.3%, p < 0.001), infarct core volume growth (142.7 ml vs. 90.5 ml, β = 47.77, 95% CI 20.97-74.57 ml, p < 0.001), and decompressive craniectomy (18.6% vs. 3.6%, p < 0.001) in the unsuccessful EVT versus MM groups.

CONCLUSION

In a randomized trial of patients with large ischemic core undergoing EVT with unsuccessful recanalization, there was no difference in very poor outcomes, sICH or death versus medically managed patients. In the unsuccessful EVT group, there were higher rates of any ICH, volume of infarct core growth, and decompressive craniectomy.

Noncontrast CT Selected Thrombectomy vs Medical Management for Late-Window Anterior Large Vessel Occlusion

BACKGROUND AND OBJECTIVES

There is uncertainty whether patients with large vessel occlusion (LVO) presenting in the late 6-hour to 24-hour time window can be selected for endovascular therapy (EVT) by noncontrast CT (NCCT) and CT angiography (CTA) for LVO detection. We evaluated the clinical outcomes of patients selected for EVT by NCCT compared with those medically managed in the extended time window.

METHODS

This multinational cohort study was conducted at 66 sites across 10 countries. Consecutive patients with proximal anterior LVO stroke selected for EVT by NCCT or medically managed and presenting within 6-24 hours of time last seen well (TSLW) from January 2014 to May 2022 were included. The primary end point was the 90-day ordinal shift in the modified Rankin Scale (mRS) score. Inverse probability treatment weighting (IPTW) and multivariable methods were used.

RESULTS

Of 5,098 patients screened, 839 patients were included, with a median (interquartile range) age of 75 (64-83) years; 455 (54.2%) were women. There were 616 patients selected to undergo EVT by NCCT (73.4%) and 223 (26.6%) who were medically managed. In IPTW analyses, there was a more favorable 90-day ordinal mRS shift in patients selected by NCCT to EVT vs those who were medically managed (odds ratio [OR] 1.99, 95% CI 1.53-2.59; p < 0.001). There were higher rates of 90-day functional independence (mRS 0-2) in the EVT group (40.1% vs 18.4%, OR 3.31, 95% CI 2.11-5.20; p < 0.001). sICH was nonsignificantly higher in the EVT group (8.5% vs 1.4%, OR 3.77, 95% CI 0.72-19.7, p = 0.12). Mortality at 90 days was lower in the EVT vs MM group (23.9% vs 32.3%, OR 0.61, 95% CI 0.45-0.83, p = 0.002).

DISCUSSION

In patients with proximal anterior LVO in the extended time window, there was a lower rate of disability and mortality in patients selected with NCCT and CTA to EVT compared with those who were medically managed. These findings support the use of NCCT as a simpler and more inclusive approach to patient selection in the extended window.

TRIAL REGISTRATION INFORMATION

This study was registered at ClinicalTrials.gov under NCT04096248.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that for patients with proximal anterior circulation occlusion presenting with ischemic stroke from 6 to 24 hours, compared with medical management, those undergoing thrombectomy based on NCCT have reduced disability and mortality at 90 days.

The lesion core extent modulates the impact of early perfusion mismatch imaging on outcome variability after thrombectomy in stroke

Introduction

Despite profitable group effects on functional outcomes after mechanical thrombectomy (MT) in large vessel occlusion (LVO), many patients with successful reperfusion show a non-favorable long-term outcome, highlighting the necessity to identify potential biomarkers predicting outcome variability. In this regard, the role of perfusion mismatch imaging for outcome variability in the early time window within 6 h after symptom onset is a matter of debate. We attempted to investigate under which conditions early perfusion mismatch imaging accounts for variability in functional outcomes after mechanical thrombectomy.

Patients and methods

In a retrospective single-center study, we examined 190 consecutive patients with LVO who were admitted to the Medical Center Lübeck within 6 h after symptom onset, all of whom underwent MT. Perfusion mismatch was quantified by applying the Alberta Stroke Program Early CT score (ASPECTS) on CT-measured cerebral blood flow (CBF-ASPECTS) and subtracting it from an ASPECTS application on cerebral blood volume (CBV-ASPECTS), i.e., ASPECTS mismatch. Using multivariate ordinal regression models, associations between ASPECTS mismatch and modified Rankin Scale (mRS) after 90 days were assessed. Furthermore, the interaction between ASPECTS mismatch and the core lesion volume was calculated to evaluate conditional associations.

Results

ASPECTS mismatch did not correlate with functional outcomes when corrected for multiple influencing covariables. However, interactions between ASPECTS mismatch and CBV-ASPECTS [OR: 1.12 (1.06-1.18), p-value < 0.001], as well as NCCT-ASPECTS [OR: 1.15 (1.06-1.25), p-value < 0.001], did show a significant association with functional outcomes. Model comparisons revealed that, profoundly, in patients with large core lesion volumes (CBV-ASPECTS < 6 or NCCT-ASPECTS < 6), perfusion mismatch showed a negative correlation with the mRS.

Discussion and conclusion

Perfusion mismatch imaging within the first 6 h of symptom onset provides valuable insights into the outcome variability of LVO stroke patients receiving thrombectomy but only in patients with large ischemic core lesions.

Endovascular thrombectomy for large ischemic strokes: An updated living systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Recent studies indicate endovascular thrombectomy (EVT) as a safe, effective treatment for acute ischemic stroke (AIS) with large ischemic regions. Our study updates an ongoing living systematic review and meta-analysis of randomized controlled trials (RCTs) comparing outcomes of EVT to medical management only.

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Library for RCTs comparing EVT to medical management in AIS patients with large ischemic areas. Using fixed-effect models, we conducted a meta-analysis to compare functional independence, mortality, and symptomatic intracranial hemorrhage (sICH) between EVT and standard medical management. We evaluated bias risk with the Cochrane tool and graded the certainty of evidence using the GRADE approach.

RESULTS

Of 1363 new citations, we included six RCTs with a total of 1876 patients. We found low-certainty evidence of improved functional independence (risk difference [RD] 29.9%, 95% CI 17.2% to 46.9%), increase in sICH (RD 2.6%, 95% CI 0.3% to 6.4%), and a non-significant decrease in mortality (RD -1.8%, 95% CI -3.9% to 0.6%) for AIS patients with large infarcts who underwent EVT compared to medical management only.

CONCLUSION

Our revised meta-analysis suggests low-certainty evidence that there is improved functional independence, a non-significant decrease in mortality, and an increase in sICH among AIS patients with large infarcts who undergo EVT compared to those receiving medical management alone.

SYSTEMATIC REVIEW PROTOCOL REGISTRATION

PROSPERO (CRD42023398742).

Thrombectomy vs Medical Management for Posterior Cerebral Artery Stroke: Systematic Review, Meta-Analysis, and Real-World Data

BACKGROUND AND OBJECTIVES

There is a paucity of high-level evidence for endovascular thrombectomy (EVT) in posterior cerebral artery (PCA) strokes.

METHODS

The MEDLINE, Embase, and Web of Science databases were queried for well-conducted cohort studies comparing EVT vs medical management (MM) for PCA strokes. Outcomes of interest included 90-day functional outcomes, symptomatic intracranial hemorrhage (sICH), and death. The level of evidence was determined per the Oxford Centre for Evidence-Based Medicine criteria. We also conducted a propensity score matched (PSM) analysis of the 2016-2020 National Inpatient Sample (NIS) to provide support for our findings with real-world data.

RESULTS

A total of 2,095 patients (685 EVT and 1,410 MM) were identified across 5 well-conducted cohort studies. EVT was significantly associated with higher odds of no disability at 90 days (odds ratio [OR] 1.25, 95% CI 1.04-1.50, p = 0.015) but not functional independence (OR 0.87, 95% CI 0.72-1.07, p = 0.18). EVT was also associated with higher odds of sICH (OR 2.48, 95% CI 1.55-3.97, p < 0.001) and numerically higher odds of death (OR 1.32, 95% CI 0.73-2.38; p = 0.35). PSM analysis of 95,585 PCA stroke patients in the NIS showed that EVT (n = 1,540) was associated with lower rates of good discharge outcomes (24.4% vs 30.7%, p = 0.037), higher rates of in-hospital mortality (8.8% vs 4.9%, p = 0.021), higher rates of ICH (18.2% and 11.7%, p = 0.008), and higher rates of subarachnoid hemorrhage (3.9% vs 0.6%, p < 0.001). Among patients with moderate to severe strokes (NIH Stroke Scale 5 or greater), EVT was associated with significantly higher rates of good outcomes (21.7% vs 13.8%, p = 0.023) with similar rates of mortality (7.6% vs 6.6%, p = 0.67) and ICH (17.8% vs, 13.1%, p = 0.18).

DISCUSSION

Our meta-analysis revealed that while EVT may be effective in alleviating disabling deficits due to PCA strokes, it is not associated with different odds of functional independence and may be associated with higher odds of sICH. These findings were corroborated by our large propensity score matched analysis of real-world data in the United States. Thus, the decision to pursue PCA thrombectomies should be carefully individualized for each patient. Future randomized trials are needed to further explore the efficacy and safety of EVT for the treatment of PCA strokes.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in patients with acute PCA ischemic stroke, treatment with EVT compared with MM alone was associated with higher odds of no disabling deficit at 90 days and higher odds of sICH.

Blood glucose to predict symptomatic intracranial hemorrhage after endovascular treatment of acute ischemic stroke with large infarct core: a prospective observational study

Introduction

Symptomatic intracranial hemorrhage (sICH) is a serious complication of acute ischemic stroke (AIS) after endovascular treatment (EVT). Limited data exist regarding predictors and clinical implications of sICH after EVT, underscoring the significance of identifying risk factors to enhance prevention strategies. Therefore, the main objective of this study was to evaluate the incidence of sICH and identify its predictors after EVT in patients with large infarct core-AIS in the pre-circulation stage.

Methods

Using data from the EVT for the Pre-circulation Large Infarct Core-AIS Study, we enrolled patients who were treated with EVT from the Prospective Multicenter Cohort Study of Early Treatment in Acute Stroke (MAGIC) registry. Baseline demographics, medical history, vascular risk factors, blood pressure, stroke severity, radiographic features, and EVT details were collected. The patients were classified into three groups: without intracranial hemorrhage (ICH), with asymptomatic intracranial hemorrhage (aICH), and sICH, based upon the occurrence of sICH. The main outcomes were the occurrence of sICH according to the Heidelberg Bleeding Classification and functional condition at 90 days. Multivariate logistic regression analysis and receiver operating characteristic (ROC) curves were used to identify independent predictors of sICH after EVT.

Results

The study recruited a total of 490 patients, of whom 13.3% (n = 65) developed sICH. Patients with sICH had less favorable outcomes than those without intracranial hemorrhage (ICH) and those with aICH (13.8% vs. 43.5% vs. 32.2%, respectively; p < 0.001). The overall mortality was 41.8% (n = 205) at 90 days post-EVT. The univariate analysis revealed significant differences among the three groups in terms of blood glucose levels at admission, probability of favorable outcomes, incidence of brain herniation, and 90-day mortality. The multifactorial logistic regression analysis revealed that the blood glucose level at admission [odds ratio (OR) 1.169, p < 0.001, confidence interval (CI) 1.076-1.269] was an independent predictor of sICH. A blood glucose level of 6.95 mmol/L at admission was the best predictor of sICH, with an area under the ROC curve (AUC) of 0.685 (95% CI: 0.616-0.754).

Discussion

The study findings demonstrated that the probability of sICH after EVT was 13.3% in patients with pre-circulation large infarct core-AIS, and sICH increased the risk of an unfavorable prognosis. Higher blood glucose levels at admission were associated with sICH after EVT in patients with pre-circulation large infarct core AIS. These findings underscore the importance of early management strategies to mitigate this risk.

Organoids Modeling Stroke in a Petri Dish

Stroke is a common neurological disorder, the second leading cause of death, and the third leading cause of disability. Unfortunately, the only approved drug for it is tissue plasminogen, but the therapeutic window is limited. In this context, preclinical studies are relevant to better dissect the underlying mechanisms of stroke and for the drug screening of potential therapies. Brain organoids could be relevant in this setting. They are derived from pluripotent stem cells or isolated organ progenitors that differentiate to form an organ-like tissue, exhibiting multiple cell types that self-organize to form a structure not unlike the organ in vivo. Brain organoids mimic many key features of early human brain development at molecular, cellular, structural, and functional levels and have emerged as novel model systems that can be used to investigate human brain diseases including stroke. Brain organoids are a promising and powerful tool for ischemic stroke studies; however, there are a few concerns that need to be addressed, including the lack of vascularization and the many cell types that are typically present in the human brain. The aim of this review is to discuss the potential of brain organoids as a novel model system for studying ischemic stroke, highlighting both the advantages and disadvantages in the use of this technology.

Decompressive craniectomy for patients with malignant infarction of the middle cerebral artery: A pooled analysis of two randomized controlled trials

BACKGROUND

Decompressive craniectomy (DC) reduces mortality without increasing the risk of very severe disability among patients with life-threatening massive cerebral infarction. However, its efficacy was demonstrated before the era of endovascular thrombectomy trials. It remains uncertain whether DC improves the prognosis of patients with malignant middle cerebral artery (MCA) infarction receiving endovascular therapy.

METHODS

We pooled data from two trials (DEVT and RESCUE BT studies in China) and patients with malignant MCA infarction were included to assess outcomes and heterogeneity of DC therapy effect. Patients with herniation were dichotomized into DC and conservative groups according to their treatment strategy. The primary outcome was the rate of mortality at 90 days. Secondary outcomes included disability level at 90 days as measured by the modified Rankin Scale score (mRS) and quality-of-life score. The associations of DC with clinical outcomes were performed using multivariable logistic regression.

RESULTS

Of 98 patients with herniation, 37 received DC surgery and 61 received conservative treatment. The median (interquartile range) was 70 (62-76) years and 40.8% of the patients were women. The mortality rate at 90 days was 59.5% in the DC group compared with 85.2% in the conservative group (adjusted odds ratio, 0.31 [95% confidence interval (CI), 0.10-0.94]; P=0.04). There were 21.6% of patients in the DC group and 6.6% in the conservative group who had a mRS score of 4 (moderately severe disability); and 10.8% and 4.9%, respectively, had a score of 5 (severe disability). The quality-of-life score was higher in the DC group (0.00 [0.00-0.14] vs 0.00 [0.00-0.00], P=0.004), but DC treatment was not associated with better quality-of-life score in multivariable analyses (adjusted β Coefficient, 0.02 [95% CI, -0.08-0.11]; p=0.75).

CONCLUSIONS

DC was associated with decreased mortality among patients with malignant MCA infarction who received endovascular therapy. The majority of survivors remained moderately severe disability and required improvement on quality of life.

CLINICAL TRIAL REGISTRATION

The DEVT trial: http://www.chictr.org. Identifier, ChiCTR-IOR-17013568. The RESCUE BT trial: URL: http://www.chictr.org. Identifier, ChiCTR-INR-17014167.

Clinical Decision Support for Patients Presenting With Large Vessel Occlusion

A single center had a collaborative, multidisciplinary review to determine how to best implement new acute ischemic stroke trials involving large vessel occlusions. A flow diagram process map was created for clinical decision support. Patients were divided into four groups based upon size of infarct and timing of presentation. The process map, available in the electronic health record (EHR) for clinicians to reference, guides the selection of patients for endovascular therapy with neuroimaging. In addition, the process map offers guidance for discussions with families and patients experiencing large vessel occlusions with both small and large core infarcts. This manuscript describes the process of creating the process map through a multidisciplinary review and discussion, with points of controversy and how these were addressed.

Deep learning on pre-procedural computed tomography and clinical data predicts outcome following stroke thrombectomy

BACKGROUND

Deep learning using clinical and imaging data may improve pre-treatment prognostication in ischemic stroke patients undergoing endovascular thrombectomy (EVT).

METHODS

Deep learning models were trained and tested on baseline clinical and imaging (CT head and CT angiography) data to predict 3-month functional outcomes in stroke patients who underwent EVT. Classical machine learning models (logistic regression and random forest classifiers) were constructed to compare their performance with the deep learning models. An external validation dataset was used to validate the models. The MR PREDICTS prognostic tool was tested on the external validation set, and its performance was compared with the deep learning and classical machine learning models.

RESULTS

A total of 975 patients (550 men; mean±SD age 67.5±15.1 years) were studied with 778 patients in the model development cohort and 197 in the external validation cohort. The deep learning model trained on baseline CT and clinical data, and the logistic regression model (clinical data alone) demonstrated the strongest discriminative abilities for 3-month functional outcome and were comparable (AUC 0.811 vs 0.817, Q=0.82). Both models exhibited superior prognostic performance than the other deep learning (CT head alone, CT head, and CT angiography) and MR PREDICTS models (all Q<0.05).

CONCLUSIONS

The discriminative performance of deep learning for predicting functional independence was comparable to logistic regression. Future studies should focus on whether incorporating procedural and post-procedural data significantly improves model performance.

The impact of collateral therapeutics on stroke hemodynamics in normotensive and hypertensive rats: a step toward translation

Introduction

Stroke interventions that increase collateral flow have the potential to salvage penumbral tissue and increase the number of patients eligible for reperfusion therapy. We compared the efficacy of two different collateral therapeutics during transient middle cerebral artery occlusion (tMCAO) in normotensive and hypertensive rats.

Methods

The change in collateral and core perfusion was measured using dual laser Doppler in response to either a pressor agent (phenylephrine, 10 mg/kg iv or vehicle) or a collateral vasodilator (TM5441, 5 mg/kg iv or vehicle) given 30 min into tMCAO in male Wistar and spontaneously hypertensive rats (SHRs).

Results

Pressor therapy increased collateral flow in the Wistar rats but was ineffective in the SHRs. The increase in collateral flow in the Wistar rats was associated with impaired cerebral blood flow autoregulation (CBFAR) that was intact in the SHRs. TM5441 caused a decrease in collateral perfusion in the Wistar rats and a modest increase in the SHRs. The pressor therapy reduced early infarction in both groups but increased edema in the SHRs, whereas TM5441 did not have any beneficial effects in either group.

Conclusions

Thus, the pressor therapy was superior to a collateral vasodilator in increasing collateral flow and improving outcomes in the Wistar rats, likely due to pial collaterals that were pressure passive; the lack of CBF response in the SHRs to pressor therapy was likely due to intact CBFAR that limited perfusion. While TM5441 modestly increased CBF in the SHRs but not in the Wistar rats, it did not have a beneficial effect on stroke outcomes. These results suggest that collateral therapies may need to be selected for certain comorbidities.

The feasibility of mechanical thrombectomy versus medical management for acute stroke with a large ischemic territory

BACKGROUND

Mechanical thrombectomy (MT) for acute ischemic stroke is generally avoided when the expected infarction is large (defined as an Alberta Stroke Program Early CT Score of <6).

OBJECTIVE

To perform a meta-analysis of recent trials comparing MT with best medical management (BMM) for treatment of acute ischemic stroke with large infarction territory, and then to determine the cost-effectiveness associated with those treatments.

METHODS

A meta-analysis of the RESCUE-Japan, SELECT2, and ANGEL-ASPECT trials was conducted using R Studio. Statistical analysis employed the weighted average normal method for calculating mean differences from medians in continuous variables and the risk ratio for categorical variables. TreeAge software was used to construct a cost-effectiveness analysis model comparing MT with BMM in the treatment of ischemic stroke with large infarction territory.

RESULTS

The meta-analysis showed significantly better functional outcomes, with higher rates of patients achieving a modified Rankin Scale score of 0-3 at 90 days with MT as compared with BMM. In the base-case analysis using a lifetime horizon, MT led to a greater gain in quality-adjusted life-years (QALYs) of 3.46 at a lower cost of US$339 202 in comparison with BMM, which led to the gain of 2.41 QALYs at a cost of US$361 896. The incremental cost-effectiveness ratio was US$-21 660, indicating that MT was the dominant treatment at a willingness-to-pay of US$70 000.

CONCLUSIONS

This study shows that, besides having a better functional outcome at 90-days' follow-up, MT was more cost-effective than BMM, when accounting for healthcare cost associated with treatment outcome.

Optimizing workflow of urgent stroke endovascular intervention: A focused lean six sigma project

INTRODUCTION

Urgent endovascular intervention is currently accepted as the primary and critical therapeutic approach to patients whose acute ischemic stroke results from a large arterial occlusion (LAO). In this context, one of the quality metrics most widely applied to the assessment of emergency systems performance is the "door-to-puncture" (D-P) time. We undertook a project to identify the subinterval of the D-P metric causing the most impact on workflow delays and created a narrowly focused project on improving such subinterval.

METHODS

Using the DMAIC (i.e., define, measure, analyze, improve and control) approach, we retrospectively reviewed our quality stroke data for calendar year (CY) 2021 (i.e., baseline population), completed a statistical process control assessment, defined the various subintervals of the D-P interval, and completed a Pareto analysis of their duration and their proportional contribution to the D-P interval. We retooled our workflow based on these analyses and analyzed the data resulting from its implementation between May and December 2022 (i.e., outcome population).

RESULTS

The baseline population included 87 patients (44 men; mean age = 67.2 years). Their D-P process was uncontrolled, and times varied between 35-235 minutes (Mean = 97; SD = 38.40). Their door to angiography arrival (D-AA) subinterval was significantly slower than their arrival to puncture (AA-P) (73.4 v. 23.5 minutes; p < 0.01), accounted for 73% of the average length of the D-P interval. The group page activation to angiography arrival (GP-AA) subinterval accounted for 41.5% of the entire D-AA duration, making it the target of our project. The outcome population originally consisted of 38 patients (15 men; mean age = 70.3 years). Their D-P process was controlled, its times varying between 43-177 minutes (Mean = 85.8; SD = 34.46), but not significantly difference than the baseline population (p = 0.127). Their target subinterval GP-AA varied between 0-37 minutes and was significantly improved from the baseline population (Mean = 13.21 v. 29.68; p < 0.001).

CONCLUSIONS

It seems feasible and reasonable to analyze the subinterval components of complex quality metrics such as the D-P time and carry out more focused quality improvement projects. Care must be exercised when interpreting the impact on overall system performance, due to unexpected variations within interdependent subprocesses. The application of a robust and comprehensive LSS continuous quality improvement process in any CSC will have to include individualized focused projects that simultaneously control the different components of overall system performance.

Sex Differences in Outcomes of Late-Window Endovascular Stroke Therapy

BACKGROUND

The association between sex and outcome after endovascular thrombectomy of acute ischemic stroke is unclear. The aim of this study was to compare the clinical and safety outcomes between men and women treated with endovascular thrombectomy in the late 6-to-24-hour window period.

METHODS

This multicenter, retrospective observational cohort study included consecutive patients who underwent endovascular thrombectomy of anterior circulation stroke in the late window from 66 clinical sites in 10 countries from January 2014 to May 2022. The primary outcome was the 90-day ordinal modified Rankin Scale score. Secondary outcomes included 90-day functional independence (FI), return of Rankin (RoR) to prestroke baseline, FI or RoR, symptomatic intracranial hemorrhage, and mortality. Multivariable and inverse probability of treatment weighting methods were used. We explored the interaction of sex with baseline characteristics on the outcomes ordinal modified Rankin Scale and FI or RoR.

RESULTS

Of 1932 patients, 1055 were women and 877 were men. Women were older (77 versus 69 years), had higher rates of atrial fibrillation, hypertension, and greater prestroke disability, but there was no difference in baseline National Institutes of Health Stroke Scale score. Inverse probability of treatment weighting analysis showed no difference between women and men in ordinal modified Rankin Scale (odds ratio, 0.98 [95% CI, 0.79-1.21]), FI or RoR (odds ratio, 0.98 [95% CI, 0.78-1.22]), severe disability or mortality (odds ratio, 0.99 [95% CI, 0.80-1.23]). The multivariable analysis of the above end points was concordant. There were no interactions between baseline characteristics and sex on the outcomes of ordinal modified Rankin Scale and FI or RoR.

CONCLUSIONS

In late presenting patients with anterior circulation stroke treated with endovascular thrombectomy in the 6 to 24-hour window, there was no difference in clinical or safety outcomes between men and women.

Cineangiography versus standard digital subtraction angiography in mechanical thrombectomy: lowering the radiation exposure without sacrificing the outcome

BACKGROUND

Endovascular thrombectomy has become a standard procedure for the treatment of acute ischemic stroke caused by large vessel occlusion. Radiation exposure to the patient and operators during mechanical thrombectomy procedures is a concern.

METHODS

The use of a high frames per second unmasked protocol-cineangiography (CINE)-derived from cardiac intervention could mitigate radiation exposure without sacrificing procedural and clinical outcomes.

RESULTS

The analysis of a prospective-maintained monocentric database of 131 patients who underwent mechanical thrombectomy (65 with the CINE protocol and 66 with the conventional digital subtraction angiography (DSA) protocol) showed a significant reduction in radiation exposure for both air kerma (AK) and dose-area product (DAP) indicators (AK 463.7 mGy vs 772 mGy, P<0.01; DAP 41.35 Gy/cm2 CINE vs 83.77 Gy/cm2 DSA, P<0.01), with no differences regarding both safety and efficacy outcomes (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b 78.4% CINE and 81.5% DSA, P=0.79; overall complications rate both intracranial and extracranial 23% CINE and 19.6% DSA, P=0.65). There were no significant differences in post-thrombectomy radiographic hemorrhagic conversion rate (P=0.77) or functional independence on discharge defined as modified Rankin Scale score ≤2 (P=0.39). A post-hoc image assessment of vessel point occlusion and recanalization mTICI score performed by three experienced interventional neuroradiologists not involved in the procedure showed a non-significant difference between the two groups regarding occlusion point (0.928 vs 0.953, P=0.31) and recanalization grade (0.814 vs 0.847, P=0.62).

CONCLUSIONS

Our initial experience demonstrated that reduction of the quality of CINE images caused no modifications in safety and efficacy and should fit within the context of diagnostic requests in an intracranial revascularization procedure.

Alberta Stroke Program Early Computed Tomography Score, Infarct Core Volume, and Endovascular Therapy Outcomes in Patients With Large Infarct: A Secondary Analysis of the ANGEL-ASPECT Trial

Importance

Endovascular therapy (EVT) demonstrated better outcomes compared with medical management in recent randomized clinical trials (RCTs) of patients with large infarct.

Objective

To compare outcomes of EVT vs medical management across different strata of the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and infarct core volume in patients with large infarct.

Design, Setting, and Participants

This prespecified secondary analysis of subgroups of the Endovascular Therapy in Acute Anterior Circulation Large Vessel Occlusive Patients With a Large Infarct Core (ANGEL-ASPECT) RCT included patients from 46 stroke centers across China between October 2, 2020, and May 18, 2022. Participants were enrolled within 24 hours of symptom onset and had ASPECTS of 3 to 5 or 0 to 2 and infarct core volume of 70 to 100 mL. Patients were divided into 3 groups: ASPECTS of 3 to 5 with infarct core volume less than 70 mL, ASPECTS of 3 to 5 with infarct core volume of 70 mL or greater, and ASPECTS of 0 to 2.

Interventions

Endovascular therapy or medical management.

Main Outcomes and Measures

The primary outcome was the ordinal 90-day modified Rankin Scale (mRS) score.

Results

There were 455 patients in the trial; median age was 68 years (IQR, 60-73 years), and 279 (61.3%) were male. The treatment effect did not vary significantly across the 3 baseline imaging subgroups (P = .95 for interaction). The generalized odds ratio for the shift in the 90-day mRS distribution toward better outcomes with EVT vs medical management was 1.40 (95% CI, 1.06-1.85; P = .01) in patients with ASPECTS of 3 to 5 and infarct core volume less than 70 mL, 1.22 (95% CI, 0.81-1.83; P = .23) in patients with ASPECTS of 3 to 5 and infarct core volume of 70 mL or greater, and 1.59 (95% CI, 0.89-2.86; P = .09) in patients with ASPECTS of 0 to 2.

Conclusions and Relevance

In this study, no significant interaction was found between baseline imaging status and the benefit of EVT compared with medical management in patients with large infarct core volume. However, estimates within subgroups were underpowered. A pooled analysis of large core trials stratified by ASPECTS and infarct core volume strata is warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT04551664.

Preserved Corticospinal Tract Revealed by Acute Perfusion Imaging Relates to Better Outcome After Thrombectomy in Stroke

BACKGROUND

The indication for mechanical thrombectomy (MT) in stroke patients with large vessel occlusion has been constantly expanded over the past years. Despite remarkable treatment effects at the group level in clinical trials, many patients remain severely disabled even after successful recanalization. A better understanding of this outcome variability will help to improve clinical decision-making on MT in the acute stage. Here, we test whether current outcome models can be refined by integrating information on the preservation of the corticospinal tract as a functionally crucial white matter tract derived from acute perfusion imaging.

METHODS

We retrospectively analyzed 162 patients with stroke and large vessel occlusion of the anterior circulation who were admitted to the University Medical Center Lübeck between 2014 and 2020 and underwent MT. The ischemic core was defined as fully automatized based on the acute computed tomography perfusion with cerebral blood volume data using outlier detection and clustering algorithms. Normative whole-brain structural connectivity data were used to infer whether the corticospinal tract was affected by the ischemic core or preserved. Ordinal logistic regression models were used to correlate this information with the modified Rankin Scale after 90 days.

RESULTS

The preservation of the corticospinal tract was associated with a reduced risk of a worse functional outcome in large vessel occlusion-stroke patients undergoing MT, with an odds ratio of 0.28 (95% CI, 0.15-0.53). This association was still significant after adjusting for multiple confounding covariables, such as age, lesion load, initial symptom severity, sex, stroke side, and recanalization status.

CONCLUSIONS

A preinterventional computed tomography perfusion-based surrogate of corticospinal tract preservation or disconnectivity is strongly associated with functional outcomes after MT. If validated in independent samples this concept could serve as a novel tool to improve current outcome models to better understand intersubject variability after MT in large vessel occlusion stroke.

Endovascular treatment for large-core ischaemic stroke: a meta-analysis of randomised controlled clinical trials

BACKGROUND AND PURPOSE

Current guidelines recommend endovascular treatment (EVT) for acute ischaemic stroke (AIS), due to large-vessel occlusion and an Alberta Stroke Program Early CT Score (ASPECTS) of ≥6. High-quality evidence resulting from randomised controlled clinical trials (RCTs) regarding EVT among large-core AIS has recently become available, justifying an updated meta-analysis aiming to evaluate efficacy and safety of EVT in this clinical setting.

METHODS

We conducted a systematic review and meta-analysis including all available RCTs that compared EVT in addition to best medical treatment (BMT) versus BMT alone for large-core AIS (defined by ASPECTS 2-5 or volumetric methods). The primary outcome was reduced disability at 3 months (≥1-point reduction across all Modified Rankin Scale (mRS) grades). Secondary outcomes included independent ambulation at 3 months (mRS score 0-3), good functional outcome at 3 months (mRS score 0-2), excellent functional outcome at 3 months (mRS score 0-1), symptomatic intracranial haemorrhage (sICH) and any intracranial haemorrhage (ICH) and mortality at 3 months. The random-effects model was used.

RESULTS

Four RCTs were included comprising a total of 662 patients treated with EVT vs 649 patients treated with BMT. Compared with BMT, EVT was significantly associated with reduced disability (common OR 1.70, 95% CI 1.39 to 2.07; I2=0%), independent ambulation (risk ratio (RR) 1.69, 95% CI 1.33 to 2.14; I2=39%) and good functional outcome (RR 2.33, 95% CI 1.76 to 3.10; I2=0%), but not with excellent functional outcome (RR 1.46, 95% CI 0.91 to 2.33; I2=39%) at 3 months. Although rates of sICH (RR 1.98, 95% CI 1.07 to 3.68; I2=0%) and any ICH (RR 2.13, 95% CI 1.70 to 2.66; I2=37%) were higher in the EVT group, 3-month mortality (RR 0.98, 95% CI 0.83 to 1.15; I2=0%) did not differ between the two groups.

CONCLUSION

EVT appears to be effective and safe and may be considered for the treatment of large-core AIS, as assessed by ASPECTS of 2-5 or volumetric methods.

PROSPERO REGISTRATION NUMBER

CRD42022334417.

Endovascular Therapy for Acute Stroke: New Evidence and Indications

Endovascular therapy (EVT) has revolutionized the treatment of acute ischemic stroke. In the past few years, endovascular treatment indications have expanded to include patients being treated in the extended window, with large ischemic core infarction, basilar artery occlusion (BAO) thrombectomy, as demonstrated by several randomized clinical trials. Intravenous thrombolysis (IVT) bridging to mechanical thrombectomy has also been studied via several randomized clinical trials, with the overall results indicating that IVT should not be skipped in patients who are candidates for both IVT and EVT. Simplification of neuroimaging protocols in the extended window to permit non-contrast CT, CTA collaterals have also expanded access to mechanical thrombectomy, particularly in regions across the world where access to advanced imaging may not be available. Ongoing study of areas to develop include rescue stenting in patients with failed thrombectomy, medium vessel occlusion thrombectomy, and carotid tandem occlusions. In this narrative review, we summarize recent trials and key data in the treatment of patients with large ischemic core infarct, simplification of neuroimaging protocols for the treatment of patients presenting in the late window, bridging thrombolysis, and BAO EVT evidence. We also summarize areas of ongoing study including medium and distal vessel occlusion.

Functional outcome in low-ASPECTS (0-5) acute ischemic stroke treated with mechanical thrombectomy: impact of laterality explored in a single-center study

Background

There is no consensus regarding the influence of infarct laterality in patients with acute ischemic stroke due to anterior large vessel occlusion (AIS-LVO) treated with mechanical thrombectomy (MT), particularly in low-ASPECT (0-5) patients who were excluded from the initial MT studies and that participated in dedicated randomized-controlled trials that do not consider the side of the occlusion. We aimed to evaluate the role of infarct laterality on the clinical outcome in low-ASPECT AIS patients treated with MT.

Material and methods

We retrospectively analyzed our institutional stroke database in our Thrombectomy-Capable Stroke Center (TCSC), including patient characteristics, procedural variables, and outcomes, between January 2015 and January 2022. Patients with acute intracranial ICA and/or proximal MCA occlusions with ASPECT ≤ 5 either on CT or MRI were included and divided into 2 groups according to the location of ischemia. The primary endpoint was a good clinical outcome at 90 days (modified Rankin Scale (mRS) score of 0-3).

Results

Between January 2015 and November 2021, 817 MT were performed, of which 82 were low-ASPECT (10.0%): 41 left-sided and 41 right-sided strokes. The rates of good clinical outcome were 30.8% (12/41) for the left-sided group and 43.6% (17/41) for the right-sided group, with a p-value of 0.349. The morality rate showed no significant difference between the two groups: 39.0% (16/41) in the right stroke group and 36.6% (15/41) in the left stroke group.

Conclusion

The clinical outcome was not significantly influenced by stroke laterality. The results of this single-center retrospective study indicate either a lack of strength or equal value in performing mechanical thrombectomy regardless of stroke laterality.