Noncontrast Computed Tomography vs Computed Tomography Perfusion or Magnetic Resonance Imaging Selection in Late Presentation of Stroke With Large-Vessel Occlusion

Haemorrhage after thrombectomy with adjuvant thrombolysis in unknown onset stroke depends on high early lesion water uptake

BACKGROUND AND PURPOSE

In wake-up stroke, CT-based quantitative net water uptake (NWU) might serve as an alternative tool to MRI to guide intravenous thrombolysis with alteplase (IVT). An important complication after IVT is symptomatic intracerebral haemorrhage (sICH). As NWU directly implies ischaemic lesion progression, reflecting blood-brain barrier injury, we hypothesised that NWU predicts sICH in patients who had a ischaemic stroke undergoing thrombectomy with unknown onset.

METHODS

Consecutive analysis of all patients who had unknown onset anterior circulation ischaemic stroke who underwent CT at baseline and endovascular treatment between December 2016 and October 2020. Quantitative NWU was assessed on baseline CT. The primary endpoint was sICH. The association of NWU and other baseline parameters to sICH was investigated using inverse-probability weighting (IPW) analysis.

RESULTS

A total of 88 patients were included, of which 46 patients (52.3%) received IVT. The median NWU was 10.7% (IQR: 5.1-17.7). The proportion of patients with any haemorrhage and sICH were 35.2% and 13.6%. NWU at baseline was significantly higher in patients with sICH (19.1% vs 9.6%, p<0.0001) and the median Alberta Stroke Program Early CT Score (ASPECTS) was lower (5 vs 8, p<0.0001). Following IPW, there was no association between IVT and sICH in unadjusted analysis. However, after adjusting for ASPECTS and NWU, there was a significant association between IVT administration and sICH (14.6%, 95% CI: 3.3% to 25.6%, p<0.01).

CONCLUSION

In patients with ischaemic stroke with unknown onset, the combination of high NWU with IVT is directly linked to higher rates of sICH. Besides ASPECTS for evaluating the extent of the early infarct lesion, quantitative NWU could be used as an imaging biomarker to assess the degree of blood-brain barrier damage in order to predict the risk of sICH in patients with wake up stroke.

Endovascular Stroke Thrombectomy for Patients With Large Ischemic Core: A Review

Importance

Recently, 6 randomized clinical trials-RESCUE-Japan-LIMIT (Recovery by Endovascular Salvage for Cerebral Ultra-Acute Embolism-Japan Large Ischemic Core Trial), ANGEL-ASPECT (Trial of Endovascular Therapy for Acute Ischemic Stroke With Large Infarct), SELECT2 (Trial of Endovascular Thrombectomy for Large Ischemic Strokes), TESLA (Thrombectomy for Emergent Salvage of Large Anterior Circulation Ischemic Stroke), TENSION (Endovascular Thrombectomy for Acute Ischemic Stroke With Established Large Infarct), and LASTE (Large Stroke Therapy Evaluation)-have concluded their investigations on the efficacy and safety of endovascular thrombectomy (EVT) for the treatment of patients with ischemic stroke, anterior-circulation large vessel occlusions, and large areas of ischemic changes defined as an Alberta Stroke Program Early Computed Tomography Score (ASPECTS) of 5 or less. Overall, the results appeared to be positive, with 5 of the 6 trials meeting their primary efficacy end point, and 1 trial that was a near miss. However, questions remain regarding how these trial results should be interpreted and incorporated into routine clinical practice.

Observations

In this narrative review and analysis of published trials, important nuances of the available clinical data were identified, and important areas of lingering uncertainty were highlighted, including the efficacy and safety of EVT for patients with a low ASPECTS score in late treatment windows and those with large core volumes. Also emphasized was the possibly important role of advanced neuroimaging modalities such as perfusion and magnetic resonance imaging when making EVT treatment decisions for select patients with low ASPECTS scores.

Conclusions and Relevance

Recent trial data provide strong evidence that EVT is safe and effective for patients with anterior, large vessel-occlusion stroke and low ASPECTS scores who present within 6 hours from stroke onset. However, patient outcomes often remain poor despite EVT treatment. The efficacy and safety of EVT for patients with low ASPECTS scores who present beyond 6 hours of stroke onset remain uncertain, and the current trial data seem too scarce to justify forgoing advanced stroke imaging during this extended time window. Furthermore, the efficacy and safety of EVT for patients with large core volumes (100 mL or greater) or M2 occlusions (ie, occlusions of the second segment of the middle cerebral artery) remain uncertain. Future research to better identify patients likely to meaningfully respond to EVT is needed to further optimize the stroke triage process and health care resource utilization.

Acute ischemic stroke with or without asymptomatic intracranial hemorrhage after endovascular treatment: a propensity-score matching study

BACKGROUND

The long-term follow-up of asymptomatic intracranial hemorrhage (aICH) in patients with acute ischemic stroke after endovascular treatment (EVT) remains controversial.ObjectiveTo evaluate the potential effect of aICH in a real-world practice setting using a matched prospective database.

METHODS

This observational cohort study enrolled patients between January 2015 and December 2022 in a prospective database. Eligible patients with occlusions in the anterior circulation were given endovascular treatment and achieved successful reperfusion. The primary outcome was functional independence (modified Rankin Scale (mRS) score 0-2). Propensity score (PS)-weighted multivariable logistic regression analyses were adjusted and were repeated in subsequent 1:1 PS-matched cohorts.

RESULTS

732 patients, 516 without any ICH and 216 with aICH, were included. 418 and 348 patients were identified after matching in the aICH substudy and hemorrhagic infarction type aICH substudy, respectively. In the postmatched population, patients with aICH had worse functional outcomes (mRS score 0-2) at 90 days than patients without any ICH (37.8% vs 55.5%: P<0.001). Worse functional outcomes were seen in patients with aICH who were older (OR=5.59 (95% CI 2.91 to 10.74)), had higher baseline National Institutes of Health Stroke Scale score (OR=6.80 (95% CI 3.72 to 12.43)), lower baseline Alberta Stroke Program Early CT Score (OR=2.08 (95% CI 1.23 to 3.51)), and who received general anesthesia (OR=3.37 (95% CI 1.92 to 5.90)).

CONCLUSIONS

This matched-control study largely confirmed that asymptomatic ICH after EVT is associated with worse functional outcomes, and the harmful effect is more significant in older patients and those with severe baseline clinical and radiological features.

Neuroendovascular Rescue 2025: Trends in Stroke Endovascular Therapy

Neuroendovascular rescue of patients with acute ischemic stroke caused by a large arterial occlusion has evolved throughout the first quarter of the present century, and continues to do so. Starting with the intra-arterial instillation of thrombolytic agents via microcatheters to dissolve occluding thromboembolic material, the current status is one that includes a variety of different techniques such as direct aspiration of thrombus, removal by stent retriever, adjuvant techniques such as balloon angioplasty, stenting, and tactical intra-arterial instillation of thrombolytic agents in smaller branches to treat no-reflow phenomenon. The results have been consistently shown to benefit these patients, irrespective of whether they had already received intravenous tissue-type plasminogen activator or not. Improved imaging methods of patient selection and tactically optimized periprocedural care measures complement this dimension of the practice of neurointervention.

Impact of stroke imaging selection modality on endovascular thrombectomy outcomes in the early and extended time windows: A meta-analysis

BACKGROUND

The effect of imaging selection modality on endovascular thrombectomy (EVT) clinical outcomes in patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO) remains unclear. This study aims to compare post-EVT outcomes in patients with AIS-LVO who underwent basic imaging (computed tomography with or without computed tomography angiography) and advanced imaging (computed tomography perfusion or magnetic resonance imaging) in early and late time windows.

METHOD

A systematic literature search was conducted on PubMed, Cochrane Library, and Embase databases from inception until June 10, 2023. Studies investigating the relationship between the imaging selection modality and post-EVT outcomes in patients with AIS-LVO were retrieved. A random-effects model was used to pool the effect estimates of successful reperfusion, symptomatic intracranial hemorrhage (sICH), functional independence, and mortality. The meta-analysis was performed using Review Manager software v.4.3, and the outcomes were assessed using odds ratios (ORs) and 95% confidence intervals (CIs).

RESULT

A total of 13 non-randomized observational studies, comprising 19,694 patients, were included in this meta-analysis. In the early time windows, AIS-LVO patients receiving advanced imaging demonstrated a higher likelihood of functional independence (OR, 1.25, 95% CI, 1.08-1.46) and a lower risk of mortality (OR,.73 95% CI,.61-.86) compared to those receiving basic imaging. In the extended time windows, AIS-LVO patients undergoing advanced imaging had a lower mortality rate (OR,.79, 95% CI,.68-.92). Regardless of the time of onset, there were no significant differences between the two groups in terms of sICH or successful reperfusion.

CONCLUSION

Advanced imaging combined with EVT may achieve better clinical outcomes in patients with AIS-LVO. Further high-quality studies are needed to validate these findings.

Effect of computed tomography vs. computed tomography perfusion on mechanical thrombectomy outcomes within 6 hours

OBJECTIVES

It is unclear which selection strategy, plain CT vs. CT perfusion (CTP), is more powerful in predicting outcome after mechanical thrombectomy (MT). We aimed to compare the effect of plain CT and CTP in predicting outcome after MT within 6 h.

METHODS

We conducted a prospective analysis of a retrospective cohort from our single-center study, which had occlusion of the internal carotid artery and middle cerebral artery up to the proximal M2 segment and received MT within 6 h. According to the Alberta Stroke Program Early CT Score (ASPECTS), patients were divided into a high-ASPECTS group (≥ 6) and a low ASPECTS group (< 6). Similarly, patients were divided into mismatch and no-mismatch groups according to the DEFUSE3 criteria for CTP. A good outcome was defined as a 90-day modified Rankin Scale (mRS) score of ≤ 3. Univariate and binary logistic regression analyses were used to investigate the association between different imaging modality and 90-day mRS score, and mortalities, respectively.

RESULTS

The high ASPECTS group included 307 patients (89.2%). The mismatch group included 189 (54.9%) patients meeting the DEFUSE3 criterion. Compared to the low ASPECTS group, the high ASPECTS group had a good outcome (odds ratio (OR), 2.285; [95% confidence interval (CI) (1.106, 4.723)], p = 0.026) and lower mortality (OR, 0.350; [95% CI (0.163, 0.752)], p = 0.007). However, there were no significant differences in good outcomes and mortality between the mismatch and no-mismatch groups.

CONCLUSIONS

Compared with plain CT, CTP does not provide additional benefits in the selection of patients suitable for MT within 6 h.

CLINICAL RELEVANCE STATEMENT

CT perfusion is not superior to plain CT for the prediction of clinical outcomes when selecting patients for mechanical thrombectomy in the first 6 h. In that clinical setting, plain CT may be safe in the absence of perfusion data.

KEY POINTS

• The advantage of CT perfusion (CTP) over CT in pre-mechanical thrombectomy (MT) screening has not been proven for patients with a large infarct core. • CTP is not better than plain CT in predicting good outcome following MT within 6 h. • Plain CT is sufficient for selecting patients suitable for MT within 6 h of large artery occlusion.

Endovascular treatment versus standard medical treatment in patients with established large infarct: a cohort study

BACKGROUND

Previous trials confirmed the benefit of endovascular treatment (EVT) in acute large core stroke, but the effect of EVT on outcomes in these patients based on noncontrast computed tomography (NCCT) in real-world clinical practice was unclear. The aim of this study was to explore the effect of EVT versus standard medical treatment (SMT) in patients with large ischemic core stroke defined as Alberta Stroke Program Early CT Score (ASPECTS) ≤5 based on NCCT alone.

MATERIALS AND METHODS

Patients with acute large core stroke at 38 Chinese centers between November 2021 and February 2023 were reviewed from a prospectively maintained database. The primary outcome was favorable functional outcome [modified Rankin Scale score (mRS), 0-3] at 90 days. Safety outcomes included 48 h symptomatic intracerebral hemorrhage (sICH) and 90-day mortality.

RESULTS

Of 745 eligible patients recruited at 38 stroke centers between November 2021 and February 2023, 490 were treated with EVT+SMT and 255 with SMT alone. One hundred and eighty-one (36.9%) in the EVT group achieved favorable functional independence versus 48 (18.8%) treated with SMT only [adjusted risk ratio (RR), 1.86; 95% CI: 1.43-2.42, P <0.001; adjusted risk difference (RD), 13.77; 95% CI: 7.40-20.15, P <0.001]. The proportion of sICH was significantly higher in patients undergoing EVT (13.3 vs. 2.4%; adjusted RR, 5.17; 95% CI: 2.17-12.32, P <0.001; adjusted RD, 10.10; 95% CI: 6.12-14.09, P <0.001). No significant difference of mortality between the groups was observed (41.8 vs. 49.0%; adjusted RR, 0.91; 95% CI: 0.77-1.07, P =0.24; adjusted RD, -5.91; 95% CI: -12.91-1.09, P =0.1).

CONCLUSION

Among patients with acute large core stroke based on NCCT in real-world, EVT is associated with better functional outcomes at 90 days despite of higher risk of sICH. Rates of procedure-related complications were relatively higher in the EVT+SMT group.

Automated identification of thrombectomy amenable vessel occlusion on computed tomography angiography using deep learning

Introduction

We developed and externally validated a fully automated algorithm using deep learning to detect large vessel occlusion (LVO) in computed tomography angiography (CTA).

Method

A total of 2,045 patients with acute ischemic stroke who underwent CTA were included in the development of our model. We validated the algorithm using two separate external datasets: one with 64 patients (external 1) and another with 313 patients (external 2), with ischemic stroke. In the context of current clinical practice, thrombectomy amenable vessel occlusion (TAVO) was defined as an occlusion in the intracranial internal carotid artery (ICA), or in the M1 or M2 segment of the middle cerebral artery (MCA). We employed the U-Net for vessel segmentation on the maximum intensity projection images, followed by the application of the EfficientNetV2 to predict TAVO. The algorithm's diagnostic performance was evaluated by calculating the area under the receiver operating characteristics curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results

The mean age in the training and validation dataset was 68.7 ± 12.6; 56.3% of participants were men, and 18.0% had TAVO. The algorithm achieved AUC of 0.950 (95% CI, 0.915-0.971) in the internal test. For the external datasets 1 and 2, the AUCs were 0.970 (0.897-0.997) and 0.971 (0.924-0.990), respectively. With a fixed sensitivity of 0.900, the specificities and PPVs for the internal test, external test 1, and external test 2 were 0.891, 0.796, and 0.930, and 0.665, 0.583, and 0.667, respectively. The algorithm demonstrated a sensitivity and specificity of approximately 0.95 in both internal and external datasets, specifically for cases involving intracranial ICA or M1-MCA occlusion. However, the diagnostic performance was somewhat reduced for isolated M2-MCA occlusion; the AUC for the internal and combined external datasets were 0.903 (0.812-0.944) and 0.916 (0.816-0.963), respectively.

Conclusion

We developed and externally validated a fully automated algorithm that identifies TAVO. Further research is needed to evaluate its effectiveness in real-world clinical settings. This validated algorithm has the potential to assist early-career physicians, thereby streamlining the treatment process for patients who can benefit from endovascular treatment.

Comparison between MRI FLAIR vascular hyperintensity-DWI mismatch and perfusion based triage for thrombectomy in the late time window

Background

The clinical impact of patient selection using FLAIR vascular hyperintensity (FVH)-diffusion-weighted imaging (DWI) mismatch for endovascular thrombectomy (EVT) in patients who have been symptomatic for over 6 h remains unclear. Herein, a retrospective study was conducted to compare the inter-rater reliability and clinical outcomes of patients selected for thrombectomy based on FVH-DWI mismatch with perfusion.

Methods

Patients with anterior-circulation large-vessel occlusion selected simultaneously with MRI and perfusion imaging in the late time window from a single-center retrospective study were categorized into EVT-applicable (FVH-DWI mismatch on MRI or perfusion imaging meeting the DEFUSE3 standards) and EVT-inapplicable groups based on MRI and perfusion imaging. The primary outcome was the 90-day functional independence rate. Safety outcomes encompassed symptomatic intracranial hemorrhage and mortality in 90 days. We assessed the consistency of the two profiles and compared the differences in functional independence rates of EVT patients among the EVT-applicable groups determined by MRI and perfusion.

Results

A total of 130 patients were enrolled, of which 114 were classified into the EVT-applicable group after triaging using MRI images. In this group, 96 patients underwent EVT, with 53 of them (55.2%) achieving functional independence. A total of 110 patients were divided into EVT-applicable group based on perfusion, among which 92 underwent EVT, with 49 of them (53.2%) achieving functional independence. The consistency of identifying EVT indication was moderate between two groups (κ = 0.42, 95% CI, 0.17-0.67). The functional independence rate was comparable between patients in the two EVT-applicable groups based on the two methods (55.2% vs. 53.2%, p = 0.789).

Conclusion

MRI triaging based on FVH-DWI mismatch showed moderate inter-rater reliability compared with perfusion-based triage and comparable efficacy in predicting clinical outcomes after EVT.

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.

Outcomes of Bridging Intravenous Thrombolysis Versus Endovascular Therapy Alone in Late-Window Acute Ischemic Stroke

BACKGROUND

Studies comparing bridging intravenous thrombolysis (IVT) with direct endovascular therapy (EVT) in patients with acute ischemic stroke who present late are limited. We aimed to compare the clinical outcomes and safety of bridging IVT in patients with acute ischemic stroke due to anterior circulation large vessel occlusion who underwent EVT 6 to 24 hours after time last known well.

METHODS

We enrolled patients with anterior circulation large vessel occlusion stroke and a National Institutes of Health Stroke Scale score of ≥6 from 20 centers across 10 countries in the multicenter retrospective CLEAR study (CT for Late Endovascular Reperfusion) between January 2014 and May 2022. We used inverse probability of treatment weighting modeling adjusted for clinical and imaging confounders to compare functional outcomes, reperfusion success, symptomatic intracranial hemorrhage, and mortality between EVT patients with and without prior IVT.

RESULTS

Of 5098 patients screened for eligibility, we included 2749 patients, of whom 549 received bridging IVT before EVT. The timing of IVT was not recorded. Witnessed stroke onset and transfer rates were higher in the bridging IVT group (25% versus 12% and 77% versus 55%, respectively, P value for both <0.0001), and time intervals between stroke onset and treatment were shorter (time last known well-start of EVT median 560 minutes [interquartile range, 432-791] versus 724 minutes [interquartile range, 544-912]; P<0.0001). After adjustment for confounders, there was no difference in functional outcome at 3 months (adjusted common odds ratio for modified Rankin Scale shift, 1.03 [95% CI, 0.89-1.19]; P=0.72) or successful reperfusion (adjusted odds ratio, 1.19 [95% CI, 0.81-1.75]; P=0.39). There were no safety concerns associated with bridging IVT versus direct EVT (symptomatic intracranial hemorrhage: adjusted odds ratio, 0.75 [95% CI, 0.38-1.48]; P=0.40; mortality: adjusted odds ratio, 1.14 [95% CI, 0.89-1.46]; P=0.31). Results were unchanged when the analysis was limited to patients who received IVT >6 hours after last known well.

CONCLUSIONS

In patients with an anterior circulation large vessel occlusion stroke who underwent EVT 6 to 24 hours from last known well, bridging IVT was not associated with a difference in outcomes compared with direct EVT.

REGISTRATION

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

Endovascular thrombectomy beyond 24 hours from last known well: a systematic review with meta-analysis

BACKGROUND

Different studies have demonstrated the benefit of endovascular treatment (EVT) up to 24 hours after acute ischemic stroke (AIS) onset. Recent cohort observational studies suggest that patients with large vessel occlusion AIS may benefit from EVT beyond 24 hours from the last known well (LKW) when adequately selected. We aimed to examine the safety and efficacy of EVT beyond 24 hours from LKW using a meta-analysis of all the literature available.

METHODS

A systematic search from inception to April 2023 was conducted for studies including AIS patients with EVT beyond 24 hours from LKW in Medline, Embase, Scopus, and Web of Science. Outcomes of interest included favorable functional outcome (90-day modified Rankin scale (mRS) 0-2), successful reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 2b-3), symptomatic intracerebral hemorrhage (sICH), and 90-day mortality. Data were pooled using a random-effects model.

RESULTS

Twelve studies with 894 patients were included. The rate of favorable functional outcome was 40% (95% CI 31% to 49%; I2=76%). The rate of successful reperfusion was 83% (95% CI 80% to 85%; I2=0%). The sICH rate was 7% (95% CI 5% to 9%; I2=0%) and the 90-day mortality rate was 28% (95% CI 24% to 33%; I2=0%). There was no significant difference in favorable outcomes (OR=0.69; 95% CI 0.41 to 1.14) and 90-day mortality (OR=1.35; 95% CI 0.90 to 2.00) among patients who underwent EVT <24 hours versus >24 hours.

CONCLUSIONS

EVT beyond 24 hours from LKW may achieve favorable clinical outcomes and high reperfusion rates, with acceptable intracranial hemorrhage rates in selected patients. Considering the current certainty of the evidence and heterogenous individual study results, larger prospective trials are warranted.

Endovascular treatment of stroke in the late time window with large vessel occlusion using the ASPECTS as an imaging screening criterion

To assess the Alberta Stroke Program Early CT Score (ASPECTS) screening tool for effectiveness in endovascular treatment of late time window stroke with large vessel occlusion. A retrospective analysis was performed of individuals administered endovascular treatment in our neurology department between 2016 and 2020 for ischemic stroke induced by acute large vessel occlusion in the anterior circulation and ASPECTS ≥ 6. Detailed baseline and endovascular treatment data were collected. Patients were assigned to 2 groups based on stroke onset time, including the 0-6 h (treated within 6 h of stroke onset) and 6-24 h (earlier/unknown time of onset, up to 24 h from the last time of appearing normal) groups. Both groups were compared for baseline information, revascularization rates, symptomatic intracranial hemorrhage, and 90-day functional independence. Totally 221 individuals were enrolled. The 0-6 h and 6-24 h groups had 129 and 92 patients, respectively, whose median ages were 64 and 63 years, respectively. Both groups were similar in previous medical history, NIHSS score at onset, lesion location and surgical complications. The 6-24 h group had elevated intracranial atherosclerotic stenosis (48.9 vs. 33.3%, P = 0.020) and revascularization (96.7 vs. 86.8%, P = 0.011) rates versus the 6-24 h group. Upon adjustment for age, sex, National Institutes of Health Stroke Scale, ASPECTS, Intracranial atherosclerosis, intraoperative tirofiban, stent detachment, successful recanalization, and symptomatic intracranial hemorrhage, the 0-6 h group had a higher rate of individuals achieving functional independence (mRS score of 0-2; 52.7 vs. 47.8%, OR = 0.242 [0.070-0.833], P = 0.024). However, the rates of individuals with a favorable outcome (mRS scores of 0-3) were similar in both groups (66.7 vs. 69.6%; OR = 0.564 [0.140-2.266], P = 0.419) as well as 90-d mortality (OR = 0.889 [0.170-4.660], P = 0.889). The ASPECTS is effective for screening individuals for endovascular treatment of stroke in the late time window with large vessel occlusion. The ASPECTS should be considered a simple and practical patient screening strategy for stroke centers without multimodal imaging evaluation.

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.

Sex Differences in Outcomes after Endovascular Thrombectomy for Patients with Acute Ischemic Stroke

INTRODUCTION

Endovascular thrombectomy (EVT) is the standard of care for patients with large-vessel occlusion acute ischemic stroke (AIS). There may be differing recanalization effectiveness based on patients' sex, and understanding such variations can improve patient outcomes by adjusting for differences. We aimed to assess the sex differences in outcome after EVT for patients with AIS.

METHODS

We retrospectively analyzed 250 consecutive AIS patients who underwent EVT from July 2019 to February 2022 across two large comprehensive tertiary care stroke centers in China. Outcomes of male patients were compared to females, where poor outcome was defined as a modified Rankin score (mRS) of 3-6 at 90 days.

RESULTS

Male patients had higher rates of symptomatic intracranial hemorrhage (sICH) (12.50% vs. 4.05%, p = 0.042) and higher hospitalization costs (114,541.08 vs. 105,790.27 RMB, p = 0.024). Male patients also had a longer median onset-to-needle time (ONT) (146.00 [104.00, 202.00] versus 120.00 [99.25, 144.75], p = 0.026). However, there were no differences in hospitalization length (p = 0.251), 90-day favorable outcome (p = 0.952), and 90-day mortality (p = 0.931) between the sexes.

CONCLUSION

Female patients had lower hospitalization costs and sICH rates than males after EVT for AIS. Identifying such differences and implementing measures, including adaptations to workflow optimization, would help to reduce the ONT and last known normal-to-puncture time seen in males to improve patient outcomes. Despite such variations, favorable outcomes and mortality are similar in female and male AIS patients.

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.

Safety and clinical outcomes of endovascular therapy versus medical management in late presentation of large ischemic stroke

INTRODUCTION

The benefit of endovascular therapy (EVT) among stroke patients with large ischemic core (ASPECTS 0-5) in the extended time window outside of trial settings remains unclear. We analyzed the effect of EVT among these stroke patients in real-world settings.

PATIENTS AND METHODS

The CT for Late Endovascular Reperfusion (CLEAR) study recruited patients from 66 centers in 10 countries between 01/2014 and 05/2022. The extended time-window was defined as 6-24 h from last-seen-well to treatment. The primary outcome was shift of the 3-month modified Rankin scale (mRS) score. Safety outcomes included symptomatic intracranial hemorrhage (sICH) and mortality. Outcomes were analyzed with ordinal and logistic regressions.

RESULTS

Among 5098 screened patients, 2451 were included in the analysis (median age 73, 55% women). Of patients with ASPECTS 0-5 (n = 310), receiving EVT (n = 209/310) was associated with lower 3-month mRS when compared to medical management (median 4 IQR 3-6 vs 6 IQR 4-6; aOR 0.4, 95% CI 0.2-0.7). Patients undergoing EVT had higher sICH (11.2% vs 4.0%; aOR 4.1, 95% CI 1.2-18.8) and lower mortality (31.6% vs 58.4%, aOR 0.4; 95% CI 0.2-0.9) compared to medically managed patients. The relative benefit of EVT was comparable between patients with ASPECTS 0 and 5 and 6-10 in the extended time window (interaction aOR 0.9; 95% CI 0.5-1.7).

CONCLUSION

In the extended time window, patients with ASPECTS 0-5 may have preserved relative treatment benefit of EVT compared to patients with ASPECTS 6-10. These findings are in line with recent trials showing benefit of EVT among real-world patients with large ischemic core in the extended time window.

TRIAL REGISTRATION NUMBER

clinicaltrials.gov; Unique identifier: NCT04096248.

A cortically-weighted versus total Alberta Stroke Program Early Computed Tomography Score in thrombectomy outcome models

OBJECTIVES

Individual subcortical infarct scoring for the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) can be difficult and is subjected to higher inter-reader variability. This study compares performance of the 10-point ASPECTS with a new 7-point cortically-weighted score in predicting post-thrombectomy functional outcomes.

MATERIALS AND METHODS

Prospective registry data from two comprehensive stroke centers (Site 1 2016-2021; Site 2: 2019-2021) included patients with either M1 segment of middle cerebral artery or internal carotid artery occlusions who underwent thrombectomy. Two multivariate proportional odds training models utilizing either 10-point or 7-point ASPECTS predicting 90-day shift in modified Rankin score were generated using Site 1 data and validated with Site 2 data. Models were compared using multiclass receiver operator characteristics, corrected Akaike's Information Criterion, and likelihood ratio test.

RESULTS

Of 328 patients (Site 1 = 181, Site 2 = 147), median age was 71y (IQR 61-82), 119 (36%) had internal carotid artery occlusions, and median 10-point ASPECTS was 9 (IQR 8-10). There was no difference in performance between models using either total or cortically-weighted ASPECTS (p=0.14). Validation cohort data were correctly (i.e., predicting modified Rankin score within one point) classified 50% (cortically-weighted score model) and 56% (total score model) of the time.

CONCLUSIONS

The 7-point cortically-weighted ASPECTS was similarly predictive of post-thrombectomy functional outcome as 10-point ASPECTS. Given noninferior performance, the cortically-weighted score is a potentially reliable, but simplified, alternative to the traditional scoring paradigm, with potential implications in automated image analysis tool development.

Thrombectomy in Patients With Ischemic Stroke Without Salvageable Tissue on CT Perfusion

BACKGROUND

Computed tomography perfusion (CTP) imaging is regularly used to guide patient selection for mechanical thrombectomy (MT). However, the effect of MT in patients without salvageable tissue on CTP has not been investigated. The purpose of this study was to assess the effect of MT in patients with stroke without perfusion mismatch profiles.

METHODS

This observational study analyzed patients with ischemic stroke consecutively treated between March 1, 2015, and January 31, 2022, triaged by multimodal-computed tomography undergoing MT. CTP lesion-core mismatch profiles were defined using a mismatch volume/ratio of ≥10 mL/1.2, respectively. The primary end point was the rate of functional independence at 90 days, defined as the modified Rankin Scale score of 0 to 2. Recanalization was evaluated with the modified Thrombolysis in Cerebral Infarction scale. The effect of baseline variables on functional outcome was assessed using multivariable logistic regression analysis. Outcomes of patients with and without CTP-mismatch profiles were compared using 1:1 propensity score matching.

RESULTS

Of 724 patients who met the inclusion criteria of this retrospective observational study, 110 (15%) patients had no CTP mismatch and were analyzed. The median age was 74 (interquartile range, 62-80) years and 53% were women. Successful recanalization (modified Thrombolysis in Cerebral Infarction score, ≥2b) was achieved in 66% (73) and associated with functional independence at 90 days (adjusted odds ratio, 7.33 [95% CI, 1.22-43.70]; P=0.03). A significant interaction was observed between recanalization and age, as well as the extent of infarction, indicating MT to be most effective in patients <70 years and with a baseline Alberta Stroke Program Early Computed Tomography Score range between 3 and 7. These findings remained stable after propensity score matching, analyzing 152 matched pairs with similar rates of functional independence between patients with and without CTP-mismatch profiles (17% versus 23%; P=0.42).

CONCLUSIONS

In patients without CTP-mismatch profiles defined according to the EXTEND (Extending the Time for Thrombolysis in Emergency Neurological Deficits) criteria, recanalization was associated with improved functional outcomes. This effect was associated with baseline Alberta Stroke Program Early Computed Tomography Score and age, but not with the time from onset to imaging.

Endovascular Therapy in the Extended Time Window for Large Vessel Occlusion in Patients With Pre-Stroke Disability

BACKGROUND AND PURPOSE

We compared the outcomes of endovascular therapy (EVT) in an extended time window in patients with large-vessel occlusion (LVO) between patients with and without pre-stroke disability.

METHODS

In this prespecified analysis of the multinational CT for Late Endovascular Reperfusion study (66 participating sites, 10 countries between 2014 and 2022), we analyzed data from patients with acute ischemic stroke with a pre-stroke modified Rankin Scale (mRS) score of 0-4 and LVO who underwent EVT 6-24 hours from the time last seen well. The primary outcome was the composite of functional independence (FI; mRS score 0-2) or return to the pre-stroke mRS score (return of Rankin, RoR) at 90 days. Outcomes were compared between patients with pre-stroke disability (pre-stroke mRS score 2-4) and those without (mRS score 0-1).

RESULTS

A total of 2,231 patients (median age, 72 years; median National Institutes of Health Stroke Scale score, 16) were included in the present analysis. Of these, 564 (25%) had pre-stroke disability. The primary outcome (FI or RoR) was observed in 30.7% of patients with pre-stroke disability (FI, 16.5%; RoR, 30.7%) compared to 44.1% of patients without (FI, 44.1%; RoR, 13.0%) (P<0.001). In multivariable logistic regression analysis with inverse probability of treatment weighting, pre-stroke disability was not associated with significantly lower odds of achieving FI or RoR (adjusted odds ratio 0.73, 95% confidence interval 0.43-1.25). Symptomatic intracranial hemorrhage occurred in 6.3% of both groups (P=0.995).

CONCLUSION

A considerable proportion of patients with late-presenting LVO and pre-stroke disability regained pre-stroke mRS scores after EVT. EVT may be appropriate for patients with pre-stroke disability presenting in the extended time window.

MMP-9 release into collateral blood vessels before endovascular thrombectomy to assess the risk of major intracerebral haemorrhages and poor outcome for acute ischaemic stroke: a proof-of-concept study

BACKGROUND

Matrix metalloproteinases (MMPs) are implied in blood-brain barrier degradation and haemorrhagic transformation following ischaemic stroke, but their local relevance in the hyperacute disease phase is unknown. We aimed to examine ultra-early MMP-9 and MMP-2 release into collateral blood vessels, and to assess its prognostic value before therapeutic recanalisation by endovascular thrombectomy (EVT).

METHODS

We report a cross-sectional proof-of-concept study including patients undergoing EVT for large-vessel ischaemic stroke at the University Hospital Würzburg, Germany. We obtained liquid biopsies from the collateral circulation before recanalisation, and systemic control samples. Laboratory workup included quantification of MMP-9 and MMP-2 plasma concentrations by cytometric bead array, immunohistochemical analyses of cellular MMP-9 and MMP-2 expression, and detection of proteolytic activity by gelatine zymography. The clinical impact of MMP concentrations was assessed by stratification according to intracranial haemorrhagic lesions on postinterventional computed tomography (Heidelberg Bleeding Classification, HBC) and early functional outcome (modified Rankin Scale, mRS). We used multivariable logistic regression, receiver-operating-characteristic (ROC) curves, and fixed-level estimates of test accuracy measures to study the prognostic value of MMP-9 concentrations.

FINDINGS

Between August 3, 2018, and September 16, 2021, 264 matched samples from 132 patients (86 [65.2%] women, 46 [34.8%] men, aged 40-94 years) were obtained. Median (interquartile range, IQR) MMP-9 (279.7 [IQR 126.4-569.6] vs 441 [IQR 223.4-731.5] ng/ml, p < 0.0001) but not MMP-2 concentrations were increased within collateral blood vessels. The median MMP-9 expression level of invading neutrophils was elevated (fluorescence intensity, arbitrary unit: 2276 [IQR 1007-5086] vs 3078 [IQR 1108-7963], p = 0.0018). Gelatine zymography experiments indicated the locally confined proteolytic activity of MMP-9 but not of MMP-2. Pretherapeutic MMP-9 release into stroke-affected brain regions predicted the degree of intracerebral haemorrhages and clinical stroke severity after recanalisation, and independently increased the odds of space-occupying parenchymal haematomas (HBC1c-3a) by 1.54 times, and the odds of severe disability or death (mRS ≥5 at hospital discharge) by 2.33 times per 1000 ng/ml increase. Excessive concentrations of MMP-9 indicated impending parenchymal haematomas and severe disability or death with high specificity.

INTERPRETATION

Measurement of MMP-9 within collateral blood vessels is feasible and identifies patients with stroke at risk of major intracerebral haemorrhages and poor outcome before therapeutic recanalisation by EVT, thereby providing evidence of the concept validity of ultra-early local stroke biomarkers.

FUNDING

This work was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) and the Interdisciplinary Centre for Clinical Research (IZKF) at the University of Würzburg.

Treatment of Acute Ischemic Stroke: The Last 30 Years of Trials and Tribulations

The landscape of acute ischemic stroke management has undergone a substantial transformation over the past 3 decades, mirroring our enhanced comprehension of the pathology and progress in diagnostic techniques, therapeutic interventions, and preventive measures. The 1990s marked a pivotal moment in stroke care with the integration of intravenous thrombolytics. However, the most significant paradigm shift in recent years has undoubtedly been the advent of endovascular thrombectomy. This article endeavors to deliver an exhaustive analysis of this revolutionary progression.

Endovascular Therapy and Outcomes Among Patients With Very Large Ischemic Core Stroke

Importance

The association of endovascular therapy (EVT) with outcomes is unclear for patients with very low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) within 24 hours of stroke onset.

Objective

To explore the association of EVT with functional and safety outcomes among patients with ASPECTS of 0 to 2 scored with noncontrast computed tomography.

Design, Setting, and Participants

This cohort study used data from an ongoing, prospective, observational, nationwide registry including all patients treated at 38 stroke centers in China with an occlusion in the internal carotid artery or M1 or M2 segment of the middle cerebral artery within 24 hours of witnessed symptom onset. Patients with ASPECTS of 0 to 2 between November 1, 2021, and February 8, 2023, were included in analysis. Data were analyzed October to November 2023.

Exposures

EVT vs standard medical treatment (SMT).

Main Outcomes and Measures

The primary outcome was favorable functional outcome, defined as modified Rankin Scale score (mRS) of 0 to 3, at 90 days. Safety outcomes included symptomatic intracerebral hemorrhage (sICH) within 48 hours and mortality at 90 days.

Results

A total of 245 patients (median [IQR] age, 71 [63-78] years; 118 [48%] women) with ASPECTS of 0 to 2 were included, of whom 111 patients (45.1%) received SMT and 135 patients (54.9%) received EVT. The EVT group had significantly greater odds of favorable functional outcome at 90 days than the SMT group (30 patients [22.2%] vs 11 patients [9.9%]; P = .01; adjusted odds ratio [aOR], 3.07 [95% CI, 1.29-7.31]; P = .01). Patients in the EVT group, compared with the SMT group, had significantly greater odds of any ICH (56 patients [41.5%] vs 16 patients [11.4%]; P < .001; aOR, 4.27 [95% CI, 2.19-8.35]; P < .001) and sICH (24 patients [17.8%] vs 1 patient [0.9%]; P < .001; aOR, 23.07 [95% CI, 2.99-177.79]; P = .003) within 48 hours. There were no differences between groups for 90-day mortality (80 patients [59.3%] vs 59 patients [53.2%]; P = .34; aOR, 1.38 [95% CI, 0.77-2.47]; P = .28). The results remained robust in the propensity score-matched analysis.

Conclusions and Relevance

In this cohort study of patients with very low ASPECTS based on NCCT within 24 hours of stroke onset, those treated with EVT had higher odds of a favorable functional outcome compared with those who received SMT. Randomized clinical trials are needed to assess these findings.

CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core

BACKGROUND

Recent trials confirmed the effectiveness of endovascular therapy in patients with large ischemic cores. Yet the optimal neuroimaging modalities to define large core remains unclear. We tried to address this question by comparing the functional outcomes in patients receiving thrombectomy selected by either noncontrast computed tomography Alberta Stroke Program Early Computed Tomography Score (ASPECTS) or computed tomography perfusion (CTP).

METHODS

This study retrospectively selected patients enrolled in the International Stroke Perfusion Registry between August 2011 and April 2022. Patients with acute stroke with large vessel occlusion in anterior circulation treated with endovascular therapy were included. All received both CTP and noncontrast computed tomography. The primary outcome was defined as poor functional outcome represented by a modified Rankin Scale score of 5 to 6 at 3 months. Large cores were defined in terms of either (1) noncontrast computed tomography ASPECTS ≤5 or (2) core volume ≥70 mL on CTP.

RESULTS

A total of 1115 patients were included in the analysis, of which 90 patients had ASPECTS ≤5 (8.1%) and 97 patients CTP core ≥70 mL (8.7%). A fair agreement between ASPECTS and CTP with a κ value of 0.31 (0.21-0.40) was found. Compared with patients with neither CTP nor ASPECTS large cores, those with only ASPECTS-defined large cores (ie, ASPECTS ≤5; n=56) did not have a higher adjusted odds of poor outcome (29%; odds ratio, 1.84 [0.91-3.73]; P=0.089). However, patients with CTP large core but not ASPECTS-defined large core (n=63) had a higher adjusted odds of poor outcome (60%; odds ratio, 3.91 [2.01-7.60]; P<0.001). In time-stratified subgroup analysis (>6 versus ≤6 hours), ASPECTS showed no discriminative difference between ≤5 and >5 in poor outcome for patients receiving endovascular therapy within 6 hours.

CONCLUSIONS

CTP core ≥70 mL-defined large cores are more predictive of poor outcome than ASPECTS ≤5-defined core in endovascular therapy patients, particularly within 6 hours after stroke onset.

Brain imaging prior to thrombectomy in the late window of large vessel occlusion ischemic stroke: a systematic review and meta-analysis

PURPOSE

Optimal imaging modalities to select patients for endovascular thrombectomy (EVT) in the late window of acute ischemic stroke due to large vessel occlusions (AIS-LVO) are not known. We conducted a systematic review comparing outcomes of patients selected by non-contrast computed tomography (NCCT)/CT angiography (CTA) vs. those selected by CT perfusion (CTP) or magnetic resonance imaging (MRI) for EVT in these patients.

METHODS

We searched PUBMED, EMBASE, and the Cochrane Library from January 1, 2000, to July 15, 2023, to identify studies comparing outcomes of patients selected for EVT by NCCT/CTA vs. CTP or MRI in the late time window for AIS-LVO. Primary outcome was independence (mRS 0-2) at 90 days or discharge. Secondary outcomes were symptomatic intracranial hemorrhage (sICH) and mortality. We pooled data across studies based on an inverse variance method.

RESULTS

Six cohort studies with 4208 patients were included. Pooled results showed no significant difference in the rate of independence at 90 days or discharge (RR 0.96, 95% CI 0.88-1.03) and sICH (RR 1.26, 0.85-1.86) between patients selected by NCCT/CTA vs. CTP or MRI for EVT in the late window of AIS-LVO. However, patients selected by NCCT/CTA vs. CTP or MRI for EVT were associated with a higher risk of mortality (RR 1.21, 1.06-1.39).

CONCLUSION

For AIS-LVO in the late window, patients selected by NCCT/CTA compared with those selected by CTP or MRI for EVT might have a comparable rate of functional independence and sICH. Baseline NCCT/CTA may triage AIS-LVO in the late window.

The novel imaging methods in diagnosis and assessment of cerebrovascular diseases: an overview

Cerebrovascular diseases, including ischemic strokes, hemorrhagic strokes, and vascular malformations, are major causes of morbidity and mortality worldwide. The advancements in neuroimaging techniques have revolutionized the field of cerebrovascular disease diagnosis and assessment. This comprehensive review aims to provide a detailed analysis of the novel imaging methods used in the diagnosis and assessment of cerebrovascular diseases. We discuss the applications of various imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and angiography, highlighting their strengths and limitations. Furthermore, we delve into the emerging imaging techniques, including perfusion imaging, diffusion tensor imaging (DTI), and molecular imaging, exploring their potential contributions to the field. Understanding these novel imaging methods is necessary for accurate diagnosis, effective treatment planning, and monitoring the progression of cerebrovascular diseases.

Clinical, Imaging Characteristics and Outcome of Intracerebral Hemorrhage Caused by Structural Vascular Lesions

BACKGROUND

The objective of this study was to investigate the clinical, imaging, and outcome characteristics of intracerebral hemorrhage (ICH) caused by structural vascular lesions.

METHODS

We retrospectively analyzed data from a prospective observational cohort study of patients with spontaneous ICH admitted to the First Affiliated Hospital of Chongqing Medical University between May 2016 and April 2021. Good outcome was defined as modified Rankin Scale score of 0-3 at 3 months. The clinical and imaging characteristics were compared between primary ICH and ICH caused by structural vascular lesions. Multivariable logistic regression analysis was performed to test the associations of etiology with clinical outcome.

RESULTS

All patients enrolled in this study were Asian. Compared with patients with primary ICH, those with structural vascular lesions were younger (48 vs. 62 years, P < 0.001), had a lower incidence of hypertension (26.4% vs. 81.7%, P < 0.001) and diabetes (7.4% vs. 16.2%, P = 0.003), and had mostly lobar hemorrhages (49.1% vs. 22.8%). ICH from structural vascular lesions had smaller baseline hematoma volume (8.4 ml vs. 13.8 ml, P = 0.010), had lower mortality rate at 30 days and 3 months (5.8% vs. 12.0%, P = 0.020; 6.7% vs. 14.8%, P = 0.007), and are associated with better functional outcome at 3 months (88% vs.70.3%, P < 0.001).

CONCLUSIONS

Compared with primary ICH, ICH due to vascular lesions has smaller hematoma volume and less severe neurological deficit at presentation and better functional outcomes.

Clinical uncertainty in large vessel occlusion ischemic stroke: does automated perfusion imaging make a difference? An intra-rater and inter-rater agreement study

BACKGROUND

Limited research exists regarding the impact of neuroimaging on endovascular thrombectomy (EVT) decisions for late-window cases of large vessel occlusion (LVO) stroke.

OBJECTIVE

T0 assess whether perfusion CT imaging: (1) alters the proportion of recommendations for EVT, and (2) enhances the reliability of EVT decision-making compared with non-contrast CT and CT angiography.

METHODS

We conducted a survey using 30 patients drawn from an institutional database of 3144 acute stroke cases. These were presented to 29 Canadian physicians with and without perfusion imaging. We used non-overlapping 95% confidence intervals and difference in agreement classification as criteria to suggest a difference between the Gwet AC1 statistics (κG).

RESULTS

The percentage of EVT recommendations differed by 1.1% with or without perfusion imaging. Individual decisions changed in 21.4% of cases (11.3% against EVT and 10.1% in favor). Inter-rater agreement (κG) among the 29 raters was similar between non-perfusion and perfusion CT neuroimaging (κG=0.487; 95% CI 0.327 to 0.647 and κG=0.552; 95% CI 0.430 to 0.675). The 95% CIs overlapped with moderate agreement in both. Intra-rater agreement exhibited overlapping 95% CIs for all 28 raters. κG was either substantial or excellent (0.81-1) for 71.4% (20/28) of raters in both groups.

CONCLUSIONS

Despite the minimal difference in overall EVT recommendations with either neuroimaging protocol one in five decisions changed with perfusion imaging. Regarding agreement we found that the use of automated CT perfusion images does not significantly impact the reliability of EVT decisions for patients with late-window LVO.

Benefit of endovascular treatment for primary versus secondary medium vessel occlusion: A multi-center experience

AIMS

This study aimed to compare the clinical outcomes and safety of endovascular treatment (EVT) in patients with primary versus secondary medium vessel occlusion (MeVO).

METHODS

From the endovascular treatment for acute ischemic stroke in the China registry, we collected consecutive patients with MeVO who received EVT. The primary endpoint was a good outcome, defined as a modified Rankin Scale (mRS) 0 to 2 at 90 days.

RESULTS

154 patients were enrolled in the final analysis, including 74 primary MeVO and 80 secondary MeVO. A good outcome at 90 days was achieved in 42 (56.8%) patients with primary MeVO and 33 (41.3%) patients with secondary MeVO. There was a higher probability of good outcomes in patients with the primary vs secondary MeVO (adjusted odds ratio, 2.16; 95% confidence interval, 1.04 to 4.46; p = 0.04). There were no significant differences in secondary and safety outcomes between MeVO groups. In the multivariable analysis, baseline ASPECTS (p = 0.001), final modified thrombolysis in cerebral infarction score (p = 0.01), and any ICH (p = 0.03) were significantly associated with good outcomes in primary MeVO patients, while baseline National Institutes of Health Stroke Scale (p = 0.002), groin puncture to recanalization time (p = 0.02), and early neurological improvement (p < 0.001) were factors associated with good outcome in secondary MeVO patients.

CONCLUSION

In MeVO patients who received EVT, there was a higher likelihood of poor outcomes in patients with secondary versus primary MeVO.

Endovascular treatment for acute ischemic stroke beyond the 24-h time window: Selection by target mismatch profile

INTRODUCTION

Endovascular treatment for acute ischemic stroke patients with large vessel occlusion (LVO) has been established as a promising clinical intervention within a late time window of 6-24 h after symptom onset. Patients with slow progression, however, may still benefit from endovascular treatment beyond the 24-h time window (very late window).

AIM

The aim of this study is to report insight into the potential clinical benefits of endovascular treatment for acute ischemic stroke beyond 24 h from symptom onset.

METHODS

A retrospective analysis was performed on consecutive patients undergoing endovascular treatment for acute anterior circulation LVO ischemic stroke beyond 24 h. Participants were recruited between July 2019 and November 2020. Patients were selected based on the DAWN/DEFUSE 3 criteria (Perfusion-RAPID, iSchemaView) and patients receiving treatment beyond 24 h were compared to a group of patients receiving endovascular treatment between 6 and 24 h after symptom onset. The primary outcome was the proportion of patients with functional independence at 90 days (modified Rankin Scale score of 0-2). The secondary outcomes were shift modified Rankin Scale (mRS) analysis and successful reperfusion was defined by thrombolysis in cerebral infarction (TICI) 2b-3 on the final procedure. Safety outcomes were symptomatic intracranial hemorrhage and death at the 90-day follow-up. Propensity score (PS)-matched analyses were employed to rectify the imbalanced baseline characteristics between the two groups.

RESULTS

A total of 166 patients were recruited with a median age of 63.0 (56.0-69.0) and 28.9% of all patients were females. Patients in the beyond 24-h group had a longer onset-to-groin time (median = 27.2 vs 14.3 h, p < 0.001) than those in the 6- to 24-h group. There were no statistically significant differences between the two groups in National Institutes of Health Stroke Scale (NIHSS) (median = 12.0 vs 15.0, p = 0.37), perfusion imaging characteristics (core: median = 11.0 vs 9.0 mL, p = 0.86; mismatch volume: median = 106.0 vs 96.0, p = 0.44; mismatch ratio = 6.46 vs 7.24, p = 0.91), and perfusion-to-groin time (median = 72.5 vs 76.0 min, p = 0.77). No significant differences were noted among patients between the two groups in the primary endpoint functional independence analysis (50.0% vs 46.6%, p = 0.77) and in the safety endpoint analysis: mortality (15.0% vs 11.0%, p = 0.71) or symptomatic hemorrhage (0% vs 3.42%, p > 0.999). In PS-matched analyses, there were no significant differences among patients between the two groups in functional independence (50.0% vs 54.8%, p = 0.74), mortality (16.7% vs 9.68%, p = 0.50), or symptomatic hemorrhage (0% vs 6.45%, p = 0.53).

CONCLUSION

Endovascular treatment can be performed safely and effectively in LVO patients beyond 24 h from symptom onset when selected by target mismatch profile. The clinical outcome of these patients was comparable to those treated in the 6- to 24-h window. Larger studies are needed to confirm these findings.

Intra-arterial tenecteplase during thrombectomy for acute stroke (BRETIS-TNK II): rationale and design

BACKGROUND

Our recent pilot study suggests intra-arterial tenecteplase (TNK) during the first pass of endovascular treatment (EVT) seems safe, may increase first-pass reperfusion and good outcome in acute ischaemic stroke (AIS) patients with large-vessel occlusion (LVO).

AIMS

To determine the efficacy and safety of intra-arterial TNK administration during EVT in AIS-LVO patients presenting up to 24 hours from symptom onset.

SAMPLE SIZE ESTIMATES

A maximum of 380 patients are required to test the superiority hypothesis with 80% power according to a two-side 0.05 level of significance, stratified by age, gender, baseline systolic blood pressure, prestroke modified Rankin Scale (mRS), baseline National Institute of Health stroke scale, baseline ASPECTS, time from onset to groin puncture, intravenous thrombolysis before EVT, stroke territory and stroke aetiology.

DESIGN

Intra-arterial TNK during thrombectomy for acute stroke (BRETIS-TNK II) study is a prospective, randomised, adaptive enrichment, open-label, blinded end point, multicentre study. Eligible AIS-LVO patients are randomly assigned into the experimental group and control group with a ratio of 1:1. The experimental group will be treated with intra-arterial infusion of TNK during EVT. The control group will be treated with standard EVT.

OUTCOME

The primary end point is a favourable outcome, defined as an mRS score of 0-2 at 90 days. The primary safety end point is symptomatic intracranial haemorrhage within 48 hours, which is defined as an increase in the National Institutes of Health Stroke Scale score of ≥4 points as a result of the intracranial haemorrhage.

CONCLUSIONS

The results of BRETIS-TNK II will provide evidence for the efficacy and safety of intra-arterial TNK administration during EVT in AIS patients with LVO.

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.

Telestroke network to robotic telestroke network: How to upgrade regional stroke care to include remote robotics?

Objective

Selected patients with large vessel occlusion (LVO) strokes can benefit from endovascular therapy (EVT). However, the effectiveness of EVT is largely dependent on how quickly the patient receives treatment. Recent technological developments have led to the first neurointerventional treatments using robotic assistance, opening up the possibility of performing remote stroke interventions. Existing telestroke networks provide acute stroke care, including remote administration of intravenous thrombolysis (IVT). Therefore, the introduction of remote EVT in distant stroke centers requires an adaptation of the existing telestroke networks. The aim of this work was to propose a framework for centers that are potential candidates for telerobotics according to the resources currently available in these centers.

Methods

In this paper, we highlight the future challenges for including remote robotics in telestroke networks. A literature review provides potential solutions.

Results

Existing telestroke networks need to determine which centers to prioritize for remote robotic technologies based on objective criteria and cost-effectiveness analysis. Organizational challenges include regional coordination and specific protocols. Technological challenges mainly concern telecommunication networks.

Conclusions

Specific adaptations will be necessary if regional telestroke networks are to include remote robotics. Some of these can already be put in place, which could greatly help the future implementation of the technology.

Penumbral Rescue by normobaric O = O administration in patients with ischemic stroke and target mismatch proFile (PROOF): Study protocol of a phase IIb trial

RATIONALE

Oxygen is essential for cellular energy metabolism. Neurons are particularly vulnerable to hypoxia. Increasing oxygen supply shortly after stroke onset could preserve the ischemic penumbra until revascularization occurs.

AIMS

PROOF investigates the use of normobaric oxygen (NBO) therapy within 6 h of symptom onset/notice for brain-protective bridging until endovascular revascularization of acute intracranial anterior-circulation occlusion.

METHODS AND DESIGN

Randomized (1:1), standard treatment-controlled, open-label, blinded endpoint, multicenter adaptive phase IIb trial.

STUDY OUTCOMES

Primary outcome is ischemic core growth (mL) from baseline to 24 h (intention-to-treat analysis). Secondary efficacy outcomes include change in NIHSS from baseline to 24 h, mRS at 90 days, cognitive and emotional function, and quality of life. Safety outcomes include mortality, intracranial hemorrhage, and respiratory failure. Exploratory analyses of imaging and blood biomarkers will be conducted.

SAMPLE SIZE

Using an adaptive design with interim analysis at 80 patients per arm, up to 456 participants (228 per arm) would be needed for 80% power (one-sided alpha 0.05) to detect a mean reduction of ischemic core growth by 6.68 mL, assuming 21.4 mL standard deviation.

DISCUSSION

By enrolling endovascular thrombectomy candidates in an early time window, the trial replicates insights from preclinical studies in which NBO showed beneficial effects, namely early initiation of near 100% inspired oxygen during short temporary ischemia. Primary outcome assessment at 24 h on follow-up imaging reduces variability due to withdrawal of care and early clinical confounders such as delayed extubation and aspiration pneumonia.

TRIAL REGISTRATIONS

ClinicalTrials.gov: NCT03500939; EudraCT: 2017-001355-31.

CTA and CTP for Detecting Distal Medium Vessel Occlusions: A Systematic Review and Meta-analysis

BACKGROUND

The optimal imaging method for detecting distal medium vessel occlusions (DMVOs) remains undefined.

PURPOSE

The objective of this study is to compare the diagnostic performance of CTA with CTP in detecting DMVOs.

DATA SOURCES

We searched PubMed, EMBASE, Web of Science Core Collection, and Cochrane Central Register of Controlled Trials up to March 31, 2023 (PROSPERO: CRD42022344006).

STUDY SELECTION

A total of 12 studies reporting accuracy values of CTA and/or CTP were included, comprising 2607 patients with 479 cases (18.3%) of DMVOs.

DATA ANALYSIS

Pooled sensitivity and specificity of both imaging methods were compared using a random-effects model. Subgroup analyses were performed based on the technique used in CTA (multi or single-phase) and the subtype of DMVOs (M2-only vs. M2 and other DMVOs). We applied Quality Assessment of Diagnostic Accuracy (QUADAS-2) tool and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) quality assessment criteria.

DATA SYNTHESIS

CTA demonstrated significantly lower sensitivity compared to CTP in detecting DMVOs [0.74, 95%CI (0.63-0.82) vs. 0.89, 95% CI (0.82-0.93), P < 0.01]. When subgrouped into single-phase and multi-phase CTA, multi-phase CTA exhibited higher sensitivity for DMVO detection than single-phase CTA [0.91, 95%CI (0.85-0.94) vs. 0.64, 95%CI (0.56-0.71), P < .01], while reaching similar levels to CTP. The sensitivity of single-phase CTA substantially decreased when extending from M2 to other non-M2 DMVOs [0.74, 95%CI (0.63-0.83) vs. 0.61, 0.95%CI (0.53-0.68), P = .02].

LIMITATIONS

We identified an overall high risk of bias and low quality of evidence, attributable to the design and reference standards of most studies.

CONCLUSIONS

Our findings highlight a significantly lower sensitivity of single-phase CTA compared to multi-phase CTA and CTP in diagnosing DMVOs.

Clinical evaluation of a deep-learning model for automatic scoring of the Alberta stroke program early CT score on non-contrast CT

BACKGROUND

Automated measurement of the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) can support clinical decision making. Based on a deep learning algorithm, we developed an automated ASPECTS scoring system (Heuron ASPECTS) and validated its performance in a prespecified clinical trial.

METHODS

For model training, we used non-contrast computed tomography images of 487 patients with acute ischemic stroke (AIS). For the clinical trial, 326 patients (87 with AIS, 56 with other acute brain diseases, and 183 with no brain disease) were enrolled. The results of Heuron ASPECTS were compared with the consensus generated by two stroke experts using the Bland-Altman agreement. A mean difference of less than 0.35 and a maximum allowed difference of less than 3.8 were considered the primary outcome target. The sensitivity and specificity of the model for the 10 regions of interest and dichotomized ASPECTS were calculated.

RESULTS

The Bland-Altman agreement had a mean difference of 0.03 [95% confidence interval (CI): -0.08 to 0.14], and the upper and lower limits of agreement were 2.80 [95% CI: 2.62 to 2.99] and -2.74 [95% CI: -2.92 to -2.55], respectively. For ASPECTS calculation, sensitivity and specificity to detect the early ischemic change for 10 ASPECTS regions were 62.78% [95% CI: 58.50 to 67.07] and 96.63% [95% CI: 96.18 to 97.09], respectively. Furthermore, in a dichotomized analysis (ASPECTS >4 vs. ≤4), the sensitivity and specificity were 94.01% [95% CI: 91.26 to 96.77] and 61.90% [95% CI: 47.22 to 76.59], respectively.

CONCLUSIONS

The current trial results show that Heuron ASPECTS reliably measures the ASPECTS for use in clinical practice.

Simplified stroke imaging selection modality for endovascular thrombectomy in the extended time window: systematic review and meta-analysis

BACKGROUND

The impact of imaging selection modality on clinical outcomes of endovascular thrombectomy (EVT) in the 6-24-hour time window remains undetermined. We compared the clinical outcomes of a simplified stroke imaging selection modality using non-contrast computed tomography (NCCT)±CT angiography (CTA) with using advanced CT perfusion (CTP).

METHODS

PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were searched from inception to 1 May 2022 to compare NCCT±CTA and CTP for patient selection for EVT in late-presenting stroke with large vessel occlusions (LVO). The primary outcome was the proportion of patients achieving functional independence (modified Rankin Scale score 0-2) within 180 days. The secondary outcomes included mortality within 90 days, successful recanalization, and any intracranial hemorrhage.

RESULTS

A total of 3419 patients in six articles were included in this meta-analysis. There was no significant difference between NCCT±CTA (no-CTP) and CTP in functional independence either in overall or subgroup analysis. However, the mortality in the no-CTP group was higher than in the CTP group. Furthermore, within the DAWN/DEFUSE 3-like subgroup, there were no significant differences in mortality, successful recanalization, and any intracranial hemorrhage between the two groups.

CONCLUSION

There was no significant difference between the simplified NCCT±CTA modality and the advanced CTP modality. The use of NCCT±CTA may represent a reasonable option for selecting patients for EVT in the extended time window, especially in the absence of CTP and acute phase MRI capabilities.

Multiphase CT angiography perfusion maps for predicting target mismatch and ischemic lesion volumes

The complexity of CT perfusion (CTP) acquisition protocols may limit the availability of target mismatch assessment at resource-limited hospitals. We compared CTP mismatch with a mismatch surrogate generated from a simplified dynamic imaging sequence comprising widely available non-contrast CT (NCCT) and multiphase CT angiography (mCTA). Consecutive patients with anterior circulation acute ischemic stroke who received NCCT, mCTA, and CTP were retrospectively included in this study. An mCTA-perfusion (mCTA-P) dynamic series was formed by co-registering NCCT and mCTA. We simulated an ideal mCTA-P study by down-sampling CTP (dCTP) dynamic images according to mCTA timing. Ischemic core and penumbra volumes were estimated by cerebral blood flow and Tmax thresholding, respectively, on perfusion maps calculated independently for CTP, dCTP, and mCTA-P by deconvolution. Concordance in target mismatch (core < 70 ml, penumbra ≥ 15 ml, mismatch ratio ≥ 1.8) determination by dCTP and mCTA-P versus CTP was assessed. Of sixty-one included patients, forty-six had a CTP target mismatch. Concordance with CTP profiles was 90% and 82% for dCTP and mCTA-P, respectively. Lower mCTA-P concordance was likely from differences in collimation width between NCCT and mCTA, which worsened perfusion map quality due to a CT number shift at mCTA. Moderate diagnostic agreement between CTP and mCTA-P was found and may improve with optimal mCTA scan parameter selection as simulated by dCTP. mCTA-P may be a pragmatic alternative where CTP is unavailable or the risks of additional radiation dose, contrast injections, and treatment delays outweigh the potential benefit of a separate CTP scan.

Automated advanced imaging in acute ischemic stroke. Certainties and uncertainties

The purpose of this is study was to review pearls and pitfalls of advanced imaging, such as computed tomography perfusion and diffusion-weighed imaging and perfusion-weighted imaging in the selection of acute ischemic stroke (AIS) patients suitable for endovascular treatment (EVT) in the late time window (6-24 h from symptom onset). Advanced imaging can quantify infarct core and ischemic penumbra using specific threshold values and provides optimal selection parameters, collectively called target mismatch. More precisely, target mismatch criteria consist of core volume and/or penumbra volume and mismatch ratio (the ratio between total hypoperfusion and core volumes) with precise cut-off values. The parameters of target mismatch are automatically calculated with dedicated software packages that allow a quick and standardized interpretation of advanced imaging. However, this approach has several limitations leading to a misclassification of core and penumbra volumes. In fact, automatic software platforms are affected by technical artifacts and are not interchangeable due to a remarkable vendor-dependent variability, resulting in different estimate of target mismatch parameters. In addition, advanced imaging is not completely accurate in detecting infarct core, that can be under- or overestimated. Finally, the selection of candidates for EVT remains currently suboptimal due to the high rates of futile reperfusion and overselection caused by the use of very stringent inclusion criteria. For these reasons, some investigators recently proposed to replace advanced with conventional imaging in the selection for EVT, after the demonstration that non-contrast CT ASPECTS and computed tomography angiography collateral evaluation are not inferior to advanced images in predicting outcome in AIS patients treated with EVT. However, other authors confirmed that CTP and PWI/DWI postprocessed images are superior to conventional imaging in establishing the eligibility of patients for EVT. Therefore, the routine application of automatic assessment of advanced imaging remains a matter of debate. Recent findings suggest that the combination of conventional and advanced imaging might improving our selection criteria.

ASPECTS-based net water uptake outperforms target mismatch for outcome prediction in patients with acute ischemic stroke and late therapeutic window

OBJECTIVE

To compare the prognostic value of net water uptake (NWU) and target mismatch (TM) on CT perfusion (CTP) in acute ischemic stroke (AIS) patients with late time window.

METHODS

One hundred and nine consecutive AIS patients with anterior-circulation large vessel occlusion presenting within 6-24 h from onset/last seen well were enrolled. Automated Alberta Stroke Program Early CT Score-based NWU (ASPECTS-NWU) was calculated from admission CT. The correlation between ASPECTS-NWU and CTP parameters was assessed. Predictors for favorable outcome (modified Rankin Scale score ≤ 2) at 90 days were assessed using logistic regression analysis. The ability of outcome prediction between ASPECTS-NWU and TM (an ischemic core < 70 mL, a mismatch ratio ≥ 1.8, and an absolute difference ≥ 15 mL) was compared using receiver operating characteristic (ROC) curve.

RESULTS

A higher level of ASPECTS-NWU was associated with a larger ischemic core (r = 0.66, p < 0.001) and a larger hypoperfusion volume (r = 0.38, p < 0.001). ASPECTS-NWU performed better than TM for outcome stratification (area under the curve [AUC], 0.738 vs 0.583, p = 0.004) and was the only independent neuroimaging marker associated with favorable outcomes compared with CTP parameters (odds ratio, 0.73; 95% confidence interval [CI] 0.62-0.87, p < 0.001). An outcome prediction model including ASPECTS-NWU and clinical variables (National Institutes of Health Stroke Scale scores and age) yielded an AUC of 0.828 (95% CI 0.744-0.893; sensitivity 65.4%; specificity 87.7%).

CONCLUSION

ASPECTS-NWU performed better than TM for outcome prediction in AIS patients with late time window and might be an alternative imaging biomarker to CTP for patient selection.

CLINICAL RELEVANCE STATEMENT

Automated Alberta Stroke Program Early CT Score-based net water uptake outperforms target mismatch on CT perfusion for the outcome prediction in patients with acute ischemic stroke and can be an alternative imaging biomarker for patient selection in late therapeutic window.

KEY POINTS

• A higher ASPECTS-based net water uptake was associated with larger ischemic cores and hypoperfusion volumes on CT perfusion. • ASPECTS-based net water uptake outperformed target mismatch for outcome prediction in acute ischemic stroke with extended therapeutic window. • ASPECTS-based net water uptake can be an alternative biomarker to target mismatch for selecting acute ischemic stroke patients with late therapeutic window.

Epidemiology, organization, diagnosis and treatment of acute ischemic stroke

The management of acute ischemic stroke is changing. Over the period of 2010-2050, the number of incident strokes is expected to be more than double. Rapid access to mechanical thrombectomy for patients with large vessel occlusion is critically associated with their functional outcome. Moreover, patients with first pass effect had a better clinical outcome, lower mortality, and fewer procedural adverse events. We discuss some advances in acute ischemic stroke regarding the organization, the diagnosis and the treatment.

Differential thrombectomy utilization across hospital classifications in the United States

OBJECTIVES

To determine hospital-level factors associated with thrombectomy uptake.

MATERIALS AND METHODS

The Nationwide Emergency Department Sample was retrospectively queried to determine the total number of thrombectomies performed based on different hospital characteristics. Joint point analysis was used to determine which years were associated with significant increases in the number of high-volume thrombectomy centers (ostensibly defined as >50 thrombectomies/year), thrombectomy-capable centers (>15 thrombectomies/year), and total number of thrombectomies performed. Multivariable logistic regression was used to determine hospital factors associated with having an increased odds of performing thrombectomies, and of being classified as a high-volume thrombectomy or a thrombectomy-capable center.

RESULTS

Between 2007-2020 there was a stepwise increase in the number of thrombectomy-capable and high-volume thrombectomy centers in the United States. In 2020, there were a total of 15,705 thrombectomies performed, with 89 high-volume thrombectomy centers, and 359 thrombectomy-capable centers. The number of thrombectomy-capable centers significantly increased after 2011. After 2013 and 2016 there was a significant change in the growth rate of high-volume thrombectomy centers. There was also a significant increase in the total number of thrombectomies performed after 2016. Hospital characteristics that were associated with an increased likelihood of being classified as thrombectomy-capable or high-volume included trauma level 1 and 2 hospitals.

CONCLUSIONS

Between 2007 and 2020, there was a marked growth in thrombectomy utilization for acute ischemic stroke. This growth outpaced new diagnoses of ischemic stroke, and was driven largely by certain hospital types, with the greatest rises following seminal publications of positive randomized thrombectomy trials.

Priorities for Advancements in Neuroimaging in the Diagnostic Workup of Acute Stroke

STAIR XII (12th Stroke Treatment Academy Industry Roundtable) included a workshop to discuss the priorities for advancements in neuroimaging in the diagnostic workup of acute ischemic stroke. The workshop brought together representatives from academia, industry, and government. The participants identified 10 critical areas of priority for the advancement of acute stroke imaging. These include enhancing imaging capabilities at primary and comprehensive stroke centers, refining the analysis and characterization of clots, establishing imaging criteria that can predict the response to reperfusion, optimizing the Thrombolysis in Cerebral Infarction scale, predicting first-pass reperfusion outcomes, improving imaging techniques post-reperfusion therapy, detecting early ischemia on noncontrast computed tomography, enhancing cone beam computed tomography, advancing mobile stroke units, and leveraging high-resolution vessel wall imaging to gain deeper insights into pathology. Imaging in acute ischemic stroke treatment has advanced significantly, but important challenges remain that need to be addressed. A combined effort from academic investigators, industry, and regulators is needed to improve imaging technologies and, ultimately, patient outcomes.

Current and future trends in acute ischemic stroke treatment: direct-to-angiography suite, middle vessel occlusion, large core, and minor strokes

Since the publication of the landmark thrombectomy trials in 2015, the field of endovascular therapy for ischemic stroke has been rapidly growing. The very low number needed to treat to provide functional benefits shown by the initial randomized trials has led clinicians and investigators to seek to translate the benefits of endovascular therapy to other patient subgroups. Even if the treatment effect is diminished, currently available data has provided sufficient information to extend endovascular therapy to large infarct core patients. Recently, published data have also shown that sophisticated imaging is not necessary for late time- window patients. As a result, further research into patient selection and the stroke pathway now focuses on dramatically reducing door-to-groin times and improving outcomes by circumventing classical imaging paradigms altogether and employing a direct-to-angio suite approach for selected large vessel occlusion patients in the early time window. While the results of this approach mainly concern patients with severe deficits, there are further struggles to provide evidence of the efficacy and safety of endovascular treatment in minor stroke and large vessel occlusion, as well as in patients with middle vessel occlusions. The current lack of good quality data regarding these patients provides significant challenges for accurately selecting potential candidates for endovascular treatment. However, current and future randomized trials will probably elucidate the efficacy of endovascular treatment in these patient populations.

Predictive Value of Acute Neurological Progression Using Bayesian CT Perfusion for Acute Ischemic Stroke with Large or Median Vessel Occlusion

Objective

Since the efficacy of mechanical thrombectomy (MT) for acute cerebral infarction due to large vessel occlusion has been proven, the time available for treatment has gradually increased. Currently, under certain conditions, treatment is indicated up to 24 h from onset. Based on neurological signs and imaging diagnosis, Stroke Treatment Guideline 2021 recommends initiation of MT within 6-24 h from onset. Herein, we retrospectively investigated the relationship between cerebral perfusion imaging evaluation and prognosis in patients with acute cerebral infarction due to large or median vessel occlusion.

Methods

Fifty-one patients diagnosed with acute cerebral infarction due to large or median vessel occlusions in anterior circulation between November 2019 and December 2021 were divided into medical care and reconstructive therapy (including tissue plasminogen activator [t-PA] therapy and MT) groups. The primary outcome was changes in the National Institutes of Health Stroke Scale (NIHSS) at admission and 1 week after onset. Patients in the medical care group were divided into those whose NIHSS did not worsen and those whose NIHSS worsened. Those in the reconstructive therapy group were divided into those whose NIHSS improved and those whose NIHSS did not improve. We evaluated the relationship between improvement factors in acute neurological symptoms and penumbral and core volumes from computed tomography perfusion performed at admission.

Results

Of 45 eligible patients, 10 received medical care without t-PA or MT and 35 underwent reconstructive therapy, including t-PA and MT. Among the 10 patients in the medical care group, 3 had worsening symptoms and 7 did not. The mean and median (interquartile range [IQR]) penumbra volumes were significantly higher in patients with worsening symptoms than in those without. The receiver operating characteristic (ROC) curve showed a threshold value of 28.6 mL with an area under the curve (AUC) of 0.952. Among the 35 patients in the reconstructive therapy group, symptoms improved for 29 but did not improve for 6. The mean and median (IQR) core volumes were significantly higher in patients whose symptoms did not improve than in those whose symptoms improved. The ROC curve showed a threshold value of 25 mL and an AUC of 0.632.

Conclusion

Evaluation of penumbra volumes could detect cases with worsening symptoms in cases where medical care was performed, and evaluation of core volumes may detect cases with non-improved symptoms in cases that received reconstructive therapy.

Recent developments in pre-hospital and in-hospital triage for endovascular stroke treatment

Triage describes the assignment of resources based on where they can be best used, are most needed, or are most likely to achieve success. Triage is of particular importance in time-critical conditions such as acute ischemic stroke. In this setting, one of the goals of triage is to minimize the delay to endovascular thrombectomy (EVT), without delaying intravenous thrombolysis or other time-critical treatments including patients who cannot benefit from EVT. EVT triage is highly context-specific, and depends on availability of financial resources, staff resources, local infrastructure, and geography. Furthermore, the EVT triage landscape is constantly changing, as EVT indications evolve and new neuroimaging methods, EVT technologies, and adjunctive medical treatments are developed and refined. This review provides an overview of recent developments in EVT triage at both the pre-hospital and in-hospital stages. We discuss pre-hospital large vessel occlusion detection tools, transport paradigms, in-hospital workflows, acute stroke neuroimaging protocols, and angiography suite workflows. The most important factor in EVT triage, however, is teamwork. Irrespective of any new technology, EVT triage will only reach optimal performance if all team members, including paramedics, nurses, technologists, emergency physicians, neurologists, radiologists, neurosurgeons, and anesthesiologists, are involved and engaged. Thus, building sustainable relationships through continuous efforts and hands-on training forms an integral part in ensuring rapid and efficient EVT triage.

Noncontrast versus perfusion CT to select endovascular therapy in an extended time window: Systematic review/meta-analysis

BACKGROUND AND PURPOSE

The effect of noncontrast CT (NCCT) on the eligibility for endovascular therapy (EVT) in an extended time window remains to be elucidated. We sought to assess the efficacy and safety of NCCT in comparison with CT perfusion (CTP) in selecting patients with acute ischemic stroke (AIS) for EVT 6-24 hours after onset.

METHODS

PubMed, Embase, and Cochrane libraries were searched from inception to August 31, 2022, to identify all studies reporting 90-day outcomes of EVT in patients with AIS in an extended time window. A meta-analysis was performed for the pooled risk ratio (RR) with 95% confidence interval (CI) using a random-effects model. The primary outcome used to assess efficacy was good functional independence, defined as a modified Rankin Scale score of 0-2 at 90 days. Secondary outcomes included successful reperfusion, symptomatic intracranial hemorrhage (sICH), and mortality at 90 days.

RESULTS

We included four nonrandomized studies with a total of 2685 patients. The outcomes of good functional independence at 90 days (RR = 0.98; 95% CI: 0.88-1.07; I2  = 0%; p = .62), successful reperfusion (RR = 0.98; 95% CI: 0.93-1.03; I2  = 50.5%; p = .11), sICH (RR = 1.11; 95% CI: 0.55-2.21; I2  = 49.4%; p = .12), or mortality at 90 days (RR = 1.18; 95% CI: 0.99-1.40; I2  = 0%; p = .42) did not differ significantly between the two groups.

CONCLUSIONS

These findings suggest that NCCT is as effective as CTP in selecting patients for EVT in an extended time window.

Angiographic collateral venous phase: a novel landmark for leptomeningeal collaterals evaluation in acute ischemic stroke

BACKGROUND

Although recanalization rates constantly increase (>80%), a favorable clinical outcome is achieved in only 45-55% of patients undergoing mechanical thrombectomy (MT) for anterior circulation stroke. Collateral circulation seems to play a major role in determining this discrepancy. The aim of the study was to investigate a novel angiographic landmark assessing the collateral venous phase (CVP) compared with the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) score, based on the arterial collateral assessment.

METHODS

Two hundred patients with anterior circulation stroke treated by MT between 2016 and 2021 were included. The ASITN/SIR score and the presence of CVP were blindly evaluated by expert neuroradiologists. Three subanalyses were performed comparing patients with good versus poor collaterals, CVP presence versus absence, and a composite analysis including both ASITN/SIR and CVP grading results.

RESULTS

Good collateral circulation (ASITN >2) was observed in 113 patients (56.5%) whereas CVP was present in 90 patients (45%) and mostly in patients with good collaterals. Favorable clinical and neuroradiological outcomes were more likely observed in patients with both good collaterals and the presence of CVP than in those with good collaterals and absence of CVP (modified Rankin Scale score 0-2: 77.3% vs 7.9%, p<0.0001; mortality: 9.3% vs 26.3%, p=0.02; 24-hour Alberta Stroke Program Early CT Score: 8 vs 6, p<0.0001), while ASITN/SIR score alone was not significantly associated with clinical outcomes.

CONCLUSIONS

The presence of CVP improves the angiographic assessment of collateral circulation. CVP could be proposed as a new imaging landmark to better understand the functionality of collaterals.