Guidelines for Mechanical Thrombectomy in Japan, the Fourth Edition, March 2020: A Guideline from the Japan Stroke Society, the Japan Neurosurgical Society, and the Japanese Society for Neuroendovascular Therapy

Endovascular therapy for acute intracranial large vessel occlusion due to atherothrombosis: Multicenter historical registry

BACKGROUND

Atherothrombotic stroke-related large vessel occlusion (AT-LVO) is caused by two etiologies, the intracranial artery occlusion due to in situ occlusion (intracranial group) or due to embolism from cervical carotid occlusion or stenosis (tandem group). The prognosis and reocclusion rate of each etiology after endovascular therapy (EVT) is unclear.

METHODS

We conducted a historical multicenter registry study at 51 Japanese centers to compare the prognoses of AT-LVO between two etiologies. The primary outcome was the incidence of recurrent ischemic stroke or reocclusion of the treated vessels within 90 days after EVT. Each of the primary outcome means the incidence of recurrent ischemic stroke and reocclusion of the treated vessels within 90 days after EVT.

RESULTS

We analyzed 582 patients (338 in the intracranial group and 244 in the tandem group). Patients in the intracranial group were younger (mean 71.9 vs 74.5, p=0.003), more of them were female and fewer of them were current smokers than those in the tandem group. In the tandem group, the patients' National Institutes of Health Stroke Scale score on admission was higher (13 vs 15, p=0.006), onset to puncture time was shorter (299 [145-631] vs 232 [144-459] minutes, p=0.03) and Alberta Stroke Program Early CT Score (ASPECTS) was lower (8 [7-9] vs 8 [6-9], p=0.0002). The primary outcome was higher in the intracranial group (22.5% vs 8.2%, p<0.0001). However, any ICH and death were not significantly different in the two groups.

CONCLUSIONS

The incidence of recurrent ischemic stroke or reocclusion after EVT for AT-LVO was higher in the intracranial group.

The Capacitated Maximal Covering Location Problem Improves Access to Stroke Treatment: A Cross-Sectional Simulation Study

Disparities in accessing advanced stroke treatment have been recognized as a policy challenge in multiple countries, including Japan, necessitating priority solutions. Nevertheless, more practical healthcare policies must be implemented due to the limited availability of healthcare staff and financial resources in most nations. This study aimed to evaluate the supply and demand balance of mechanical thrombectomy (MT) and identify areas with high priority for enhancing stroke centers. The target area of this study was Hokkaido, Japan. We adopted the capacitated maximal covering location problem (CMCLP) to propose an optimal allocation without increasing the number of medical facilities. Four realistic scenarios with varying levels of total MT supply capacity for Primary stroke centers and assuming a range of 90 minutes by car from the center were created and simulated. From scenarios 1 to 4, the coverage increased by approximately 53% to 85%, scenarios 2 and 3 had 5% oversupply, and scenario 4 had an oversupply of approximately 20%. When the supply capacity cap was eliminated and 8 PSCs received 31 or more patients, they became priority enhancement targets. The CMCLP estimates demand coverage considering the supply and demand balance and indicates areas and facilities where MT supply capacity enhancement is a priority.

Expanding the Treatable Imaging Profile in Patients With Large Ischemic Stroke: Subanalysis From a Randomized Clinical Trial

BACKGROUND

We aimed to examine the boundary of the ischemic core volume in patients undergoing endovascular thrombectomy (EVT) versus those receiving medical management to determine the minimum optimal size for favorable treatment outcomes.

METHODS

This is a prespecified substudy of the RESCUE-Japan LIMIT (Recovery by Endovascular Salvage for Cerebral Ultra-Acute Embolism-Japan Large Ischemic Core Trial). Patients with large vessel occlusion were enrolled between November 2018 and September 2021 with a National Institutes of Health Stroke Scale score of at least 6 on admission and an Alberta Stroke Program Early Computed Tomography Score value of 3 to 5. We investigated the correlation between optimal quantified ischemic core volume, assessed solely using magnetic resonance diffusion-weighted imaging, and functional outcomes (modified Rankin Scale score, 0-3) at 90 days by predictive marginal plots. Final infarct volume and safety outcomes (symptomatic intracerebral hemorrhage and mortality) were also assessed.

RESULTS

Of the 203 cases, 168 patients (85 in the EVT group versus 83 in the medical management group) were included. The median (interquartile range) core volume was 94 (65-160) mL in patients with EVT and 115 (71-141) mL in the medical management group (P=0.72). The predictive marginal probabilities of the 2 groups intersected at 128 mL for estimating functional outcomes. Symptomatic intracerebral hemorrhage and mortality within 90 days had overlay margins through all core volumes in both groups. The median final infarct volume (interquartile range) was smaller in the EVT group (142 [80-223] mL versus 211 [123-289] mL in the medical management group; P<0.001).

CONCLUSIONS

In this prespecified analysis of a randomized clinical trial involving patients with large ischemic strokes, patients with an estimated core volume of up to 128 mL on diffusion-weighted imaging benefit from EVT.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03702413.

Early neurological changes following endovascular therapy for acute stroke due to intracranial atherosclerotic disease

BACKGROUND

Endovascular therapy (EVT) reduces functional disability in patients with acute large vessel occlusion (LVO). However, the early neurological change after EVT may be limited in patients with intracranial atherosclerotic disease (ICAD).

METHODS

We analyzed the Japanese Registry of NeuroEndovascular Therapy (JR-NET) 4 which was a retrospective, nationwide, multicenter registry of patients with LVO between 2015 and 2019. We compared the early neurological change, efficacy and safety of EVT for acute LVO in ICAD and other etiologies. The primary outcome was NIHSS improvement ≥10 points, and secondary outcome were NIHSS worsening ≥4 points 7 days after EVT, effective reperfusion rate, 30-day functional outcomes, and safety outcomes.

RESULTS

Among the 6710 enrolled patients, 610 (9.1%) had ICAD. The ICAD group was younger (mean 72.0 vs. 75.8 years) and predominantly male (63.4% vs. 56.0%), had lower NIHSS scores before EVT (median 16 vs. 18), and underwent percutaneous transluminal angioplasty and stenting more frequently (43.0% vs. 4.4%, 12.3% vs. 4.4%). In the ICAD group, NIHSS improvement was significantly lower (adjusted odds ratio (aOR) [95% confidence interval (95%CI)] 0.52 [0.41-0.65]), NIHSS worsening was significantly higher (aOR [95%CI] 1.76 [1.31-2.34]), and effective reperfusion was significantly lower (aOR [95%CI] 0.47 [0.36-0.60]). Fewer patients with ICAD had modified Rankin scale 0-2 at 30 days (aOR [95%CI] 0.60 [0.47-0.77]). The risk of acute reocclusion was more prominent in the ICAD group (aOR [95%CI] 4.03 [1.98-8.21]).

CONCLUSIONS

Improvement in neurological severity after EVT was lower in patients with LVO and ICAD.

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.

Technical and clinical outcomes of thrombectomy in patients with acute medium vessel occlusion and large vessel occlusion; sub-analyses of Japan Trevo registry

BACKGROUND

Little is known about endovascular therapy (EVT) for patients with medium vessel occlusion (MeVO) and more work is needed to establish its efficacy and to understand hemorrhagic complications.

METHODS

We analyzed the Japan Trevo Registry, which enrolled patients with acute stroke who underwent EVT using Trevo Retriever alone or in combination with an aspiration catheter. The primary outcome was effective reperfusion, and the secondary outcome was modified Rankin scale 0-2 at 90 days. Safety outcomes, including intracranial hemorrhage (ICH), were evaluated using a subgroup analyses focused on any ICH.

RESULTS

Among 1041 registered patients, 1025 patients were analyzed. 253 patients had MeVOs, and the majority (89.3%) had middle cerebral artery segment 2 (M2). The median National Institutes of Health Stroke Scale scores at admission were 15 and 19 for the MeVO and LVO groups (p < 0.0001). The primary outcome was 88.9% in MeVO vs. 91.8% in LVO group: adjusted odds ratio (aOR) [95% confidence interval (CI)] 0.60 [0.35-1.03], p = 0.07, and the secondary outcome was 43.2% vs. 42.2%, and the aOR [95%CI] was 0.70 [0.48-1.002], p = 0.051. However, the incidence of any ICH was more prominent in MeVO than in LVO group (35.7% vs. 28.8%, aOR [95%CI] 1.54 [1.10-2.15], p = 0.01). In subgroup analyses, the incidences of any ICH in MeVO group were generally higher than those in LVO group.

CONCLUSIONS

The effective reperfusion rate did not differ significantly between MeVO and LVO groups. Future development of devices and treatments for MeVO with fewer hemorrhagic complications is desirable.

Fluid-attenuated inversion recovery vascular hyperintensity-diffusion-weighted imaging mismatch and functional outcome after endovascular reperfusion therapy for acute ischemic stroke

BACKGROUND

Fluid-attenuated inversion recovery vascular hyperintensity (FVH) outside of the diffusion-weighted imaging (DWI) lesion, termed FVH-DWI mismatch, may represent penumbral tissue with good collateral status.

METHODS

Consecutive patients who underwent endovascular reperfusion therapy (EVT) for acute internal carotid artery (ICA) or middle cerebral artery (MCA)-M1 occlusion were enrolled. FVH-DWI mismatch score was defined as the number of cortical Alberta Stroke Program Early CT Score areas (I and M1 to M6) that involved FVH but no DWI lesion (0 to 7 points). The outcome measure was set as good functional outcome, defined as a modified Rankin Scale score of 0 to 2, at 90 days after onset.

RESULTS

Of 196 consecutive patients who underwent EVT for acute ICA or MCA-M1 occlusion, 32 without brain MRI before EVT were excluded, and the remaining 164 were analyzed. The median FVH-DWI mismatch score was 2 (interquartile range, 0 to 4). At 90 days after EVT, 2 patients were lost-to follow-up, and 73 had good functional outcome. The frequency of good functional outcome at 90 days after EVT increased significantly with increasing FVH-DWI mismatch score (P for trend <0.001). FVH-DWI mismatch score was independently associated with good functional outcome at 90 days after onset (adjusted odds ratio per 1 point,1.46; 95% confidence interval, 1.15-1.89).

CONCLUSIONS

Patients with large FVH-DWI mismatch had good functional outcome after EVT for acute ICA or MCA-M1 occlusion.

A Single-Center Experience of Mechanical Thrombectomy for Cancer-Associated Ischemic Stroke

Objectives

Cancer-associated ischemic stroke tends to extend over multiple vascular territories and develops under poor general conditions. Owing to the rarity of such cases and poor prognoses, no comprehensive studies on mechanical thrombectomy for cancer-associated ischemic stroke have been reported in Japan. The present study investigated the radiological and clinical characteristics of mechanical thrombectomy in patients with cancer-associated ischemic stroke at our institution.

Methods

We retrospectively reviewed 108 patients who underwent mechanical thrombectomy for large cerebral artery occlusion between January 1, 2021, and October 31, 2022, at our institution. The characteristics of mechanical thrombectomy in the cancer-associated ischemic stroke group were compared with those in the control group.

Results

Of the 108 patients (112 procedures), seven patients (eight procedures) with clinically diagnosed cancer-associated ischemic stroke underwent mechanical thrombectomy. Of the eight procedures, six were performed during hospitalization. In contrast, only 10 of 104 procedures were performed in the control group. The in-hospital onset rate was higher in the cancer-associated ischemic stroke group (75.0%) compared to that in the controls (9.6%); p <0.001. The puncture-to-reperfusion time was significantly longer in the cancer-associated ischemic stroke group in comparison to that in the controls with a median interquartile range of 69 minutes (60.0-82.0 minutes) and 59.5 minutes (44.5-69.3 minutes), respectively (p <0.01). However, the rates of successful recanalization defined as thrombolysis in cerebral infarction ≥2b were not significantly different between the cancer-associated ischemic stroke group and controls with values of 62.5% and 79.8%, respectively (p = 0.250). Of the eight cases in the cancer-associated ischemic stroke group, only one (12.5%) had a good outcome on a modified Rankin Scale score of 0 to 2 at discharge, in contrast to 23 of the 104 (23.1%) cases in the controls (p = 0.523). Histopathological examination of six retrieved thrombi in the cancer-associated stroke group using hematoxylin and eosin staining revealed that only one case showed an erythrocyte-dominant thrombus while five displayed a fibrinoplatelet-dominant component. Conversely, 65 of 92 retrieved thrombi in the control group were erythrocyte dominant. Cancer was pathologically diagnosed in four of seven patients, all of which were adenocarcinomas.

Conclusion

Cancer-associated ischemic stroke tends to occur during hospitalization. Coagulation disorders associated with cancer, especially adenocarcinoma, may be related to the formation of thrombi with fibrinoplatelet-dominant components, leading to ischemic stroke. The procedural time for mechanical thrombectomy in cancer-associated ischemic stroke tends to be longer.

Prognostic Determinants of Anterior Large Vessel Occlusion in Acute Stroke in Elderly Patients

This study investigated prognostic factors in elderly patients (80 years and older) undergoing mechanical thrombectomy (MT) for anterior circulation large vessel occlusion (LVO) in acute stroke treatment. Of 59 cases, 47.5% achieved a favorable outcome (mRS ≤ 3) at three months, with a mortality rate of 20.3%. Factors associated with better outcomes included younger age, lower admission National Institute of Health Stroke Scale (NIHSS) scores, lower N-terminal pro-brain natriuretic peptide (NT-proBNP) and D-dimer levels, the presence of the first pass effect (FPE), and successful recanalization. However, logistic regression showed that only lower admission NIHSS scores were significantly correlated with favorable outcomes. In addition, this study suggests that lower admission NT-proBNP and D-dimer levels could potentially serve as prognostic indicators for elderly LVO patients undergoing MT.

Improvement of Functional Outcomes in Patients with Stroke who Received Alteplase for Over 15 Years: Japan Stroke Data Bank

AIM

The nationwide verification of intravenous thrombolysis (IVT) was rarely performed after the extension of the therapeutic time window of alteplase or after the expansion of mechanical thrombectomy (MT). We aimed to examine the long-term change in accurate real-world outcomes of IVT in patients with acute ischemic stroke (AIS) using the Japan Stroke Databank, a representative Japan-wide stroke database.

METHODS

We extracted all patients with AIS who received IVT with alteplase between October 11, 2005, the approval date for alteplase use for AIS in Japan, and December 31, 2020. Patients were categorized into three groups using two critical dates in Japan as cutoffs: the official extension date of the therapeutic time window for IVT to within 4.5 h of symptom onset and the publication date of the revised guideline, where the evidence level of MT was heightened. We assessed the yearly trend of IVT implementation rates and the secular changes and three-group changes in clinical outcomes at discharge.

RESULTS

Of 124,382 patients with AIS, 9,569 (7.7%) received IVT (females, 41%; median age, 75 years). The IVT implementation rate has generally increased over time and plateaued in recent years. The proportion of favorable outcomes (modified Rankin Scale score of 0-2) increased yearly over 15 years. The results of the changes in the outcomes of the three groups were similar to those of the annual changes.

CONCLUSIONS

We revealed that IVT implementation rates in patients with AIS increased, and the functional outcome in these patients improved over 15 years. Therefore, the Japanese IVT dissemination strategy is considered appropriate and effective.

Japan Trevo Registry: Real-world Registry of Stent Retriever Alone or in Combined Therapy with Aspiration Catheter for Acute Ischemic Stroke in Japan

Endovascular therapy (EVT) for real-world patients after extended time frames is associated with concerns about its efficacy and safety. We conducted a prospective registry at 77 centers between November 2019 and October 2020. The registry criteria included patients treated with Trevo Retriever alone or in combined therapy with an aspiration catheter. The primary outcome was effective reperfusion (thrombolysis in cerebral infarction grade ≥ 2b), the secondary outcome was a modified Rankin scale 0-2 at 90 days, and the safety outcomes were worsening of neurologic symptoms within 24 h postoperatively, intracranial hemorrhage (ICH) within 24 h after EVT and mortality. We also exlpored the difference between patients whose last known well time (LKWT) to a puncture was less than 6 h (0-6 h) and those whose LKWT was 6 h or more but less than 24 h (6-24 h). Among the 1041 patients registered, 1025 patients were analyzed. The mean age was 76.9 years, and 53.6% of the participants were males. The 6-24 h group was 206/998 (20.6%), the median National Institute of Health Stroke Scale (NIHSS) score at admission was 18, and the median Alberta Stroke Program Early CT score was 8. Combined technique as the first pass was used on 817 (79.7%) patients. The primary outcome was 934 (91.1%). The secondary outcome was 433/1021 (42.4%). Symptomatic ICH, any ICH, and mortality were 10/1019 (1.0%), 311/1019 (30.5%), and 75 (7.3%). In the subanalysis, the 6-24 h group was lower in NIHSS (median;18 vs 16), and the secondary outcome was not significantly different in the <6 h group. Even after treatment time expansion, this result was comparable to other Trevo-based trials and nationwide registries.

Optimal allocation of physicians improves accessibility and workload disparities in stroke care

BACKGROUND

Inequalities in access to stroke care and the workload of physicians have been a challenge in recent times. This may be resolved by allocating physicians suitable for the expected demand. Therefore, this study analyzes whether reallocation using an optimization model reduces disparities in spatial access to healthcare and excessive workload.

METHODS

This study targeted neuroendovascular specialists and primary stroke centers in Japan and employed an optimization model for reallocating neuroendovascular specialists to reduce the disparity in spatial accessibility to stroke treatment and workload for neuroendovascular specialists in Japan. A two-step floating catchment area method and an inverted two-step floating catchment area method were used to estimate the spatial accessibility and workload of neuroendovascular specialists as a potential crowdedness index. Quadratic programming has been proposed for the reallocation of neuroendovascular specialists.

RESULTS

The reallocation of neuroendovascular specialists reduced the disparity in spatial accessibility and the potential crowdedness index. The standard deviation (SD) of the demand-weighted spatial accessibility index improved from 125.625 to 97.625. Simultaneously, the weighted median spatial accessibility index increased from 2.811 to 3.929. Additionally, the SD of the potential crowdedness index for estimating workload disparity decreased from 10,040.36 to 5934.275 after optimization. The sensitivity analysis also showed a similar trend of reducing disparities.

CONCLUSIONS

The reallocation of neuroendovascular specialists reduced regional disparities in spatial accessibility to healthcare, potential crowdedness index, and disparities between facilities. Our findings contribute to planning health policies to realize equity throughout the healthcare system.

Intravenous alteplase before endovascular therapy for acute large vessel occlusion with large ischemic core: subanalysis of a randomized clinical trial

BACKGROUND

The efficacy of endovascular therapy (EVT) in patients with large ischemic core has been reported, but it remains unclear whether IV alteplase (IVT) has beneficial effects in addition to EVT in such patients. We evaluated the efficacy and safety of EVT with or without IVT.

METHODS

The RESCUE-Japan LIMIT was an open-label, prospective, multicenter, randomized clinical trial to evaluate the efficacy and safety of EVT in stroke patients with large ischemic core, defined as Alberta Stroke Program Early CT Score (ASPECTS) 3-5. This subanalysis evaluated the differences in the effects of EVT with medical care (EVT group) compared with medical care alone (No-EVT group) between those who received IVT (IVT stratum) and those who did not (No-IVT stratum) before EVT.

RESULTS

Among 202 enrolled patients, 147 (73%) did not receive IVT. In the No-IVT stratum, the modified Rankin Scale (mRS) score of 0-3 at 90 days was significantly higher in the EVT group than in the No-EVT group (31.1% vs 12.3%, OR 3.21 (95% CI 1.37 to 7.53)). In the IVT stratum, the mRS score of 0-3 was 30.8% in the EVT group and 13.8% in the No-EVT group (OR 2.78 (95% CI 0.72 to 10.7)) (interaction p=0.77). The incidence of symptomatic intracranial hemorrhage was not different between the two groups in the No-IVT stratum (OR 1.20 (95% CI 0.35 to 4.12)), but it was significantly higher in the EVT group than in the No-EVT group in the IVT stratum (11.5% vs 0%, p=0.03).

CONCLUSIONS

There was no difference in efficacy of EVT with or without IVT, while IVT before EVT might increase symptomatic intracranial hemorrhage in patients with large ischemic core.

TRIAL REGISTRATION INFORMATION

NCT03702413.

Characteristics and outcomes of unknown onset stroke: The Japan Stroke Data Bank

BACKGROUND

Clinical outcomes of unknown onset stroke (UOS) are influenced by the enlargement of the therapeutic time window for reperfusion therapy. This study aimed to investigate and describe the characteristics and clinical outcomes of patients with UOS.

METHODS

Patients with acute ischemic stroke (AIS) who were admitted within 24 h of their last known well time, from January 2017 to December 2020, were included. Data were obtained from a long-lasting nationwide hospital-based multicenter prospective registry: the Japan Stroke Data Bank. The co-primary outcomes were the National Institutes of Stroke Scale (NIHSS) scores on admission and unfavorable outcomes at discharge, corresponding to modified Rankin Scale (mRS) scores of 3-6.

RESULTS

Overall, 26,976 patients with AIS were investigated. Patients with UOS (N = 5783, 78 ± 12 years of age) were older than patients with known onset stroke (KOS) (N = 21,193, 75 ± 13 years of age). Age, female sex, higher premorbid mRS scores, atrial fibrillation, and congestive heart failure were associated with UOS in multivariate analysis. UOS was associated with higher NIHSS scores (median = 8 [interquartile range [IQR]: 3-19] vs. 4 [1-10], adjusted incidence rate ratio = 1.37 [95% CI: 1.35-1.38]) and unfavorable outcomes (52.1 vs. 33.6%, adjusted odds ratio = 1.27 [1.14-1.40]). Intergroup differences in unfavorable outcomes were attenuated among females (1.12 [0.95-1.32] vs. males 1.38 [1.21-1.56], P = 0.040) and in the subgroup that received reperfusion therapy (1.10 [0.92-1.33] vs. those who did not receive therapy 1.23 [1.08-1.39], P = 0.012).

CONCLUSIONS

UOS was associated with unfavorable outcomes but to a lesser degree among females and patients receiving reperfusion therapy.

Endovascular Thrombectomy for Acute Stroke with a Large Ischemic Core: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Endovascular thrombectomy (ET) efficacy and safety in stroke with a large ischemic core is still inconclusive as this population has been underrepresented in ET randomized controlled trials (RCTs).

METHODS

We conducted a systematic review and meta-analysis synthesizing RCTs, which were retrieved by systematically searching: PubMed, Web of Science, SCOPUS, and Cochrane through February 18th, 2023. Our primary outcome was neurological disability measured by the modified Rankin scale (mRS). Dichotomous outcomes were pooled using risk ratio (RR) along with confidence interval (CI) using Revman V. 5.4 software.

RESULTS

Three RCTs with a total of 1010 patients were included in our analysis. ET significantly increased the rates of functional independence (mRS ≤ 2) (RR: 2.54 with 95% CI [1.85, 3.48]), independent ambulation (mRS ≤ 3) (RR: 1.78 with 95% CI [1.28, 2.48]), and early neurological improvement (RR: 2.46 with 95% CI [1.60, 3.79]). However, there was no difference between endovascular thrombectomy and medical care in excellent neurological recovery (mRS ≤ 1) (RR: 1.35 with 95% CI [0.88, 2.08]). Also, ET significantly reduced the rate of poor neurological recovery (mRS 4-6) (RR: 0.79 with 95% CI [0.72, 0.86]). However, endovascular thrombectomy was associated with more incidence of any intracranial hemorrhage (RR: 2.40 with 95% CI [1.90, 3.01] [0.72, 0.86]).

CONCLUSION

ET combined with medical care was associated with better functional outcomes compared with medical care alone. However, ET was associated with a higher rate of intracranial hemorrhage. This can support extending ET indication in the management of stroke with a large ischemic core.

Mode of Imaging Study and Endovascular Therapy for a Large Ischemic Core: Insights From the RESCUE-Japan LIMIT

BACKGROUND AND PURPOSE

Differences in measurement of the extent of acute ischemic stroke using the Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) by non-contrast computed tomography (CT-ASPECTS stratum) and diffusion-weighted imaging (DWI-ASPECTS stratum) may impact the efficacy of endovascular therapy (EVT) in patients with a large ischemic core.

METHODS

The RESCUE-Japan LIMIT (Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism Japan-Large IscheMIc core Trial) was a multicenter, open-label, randomized clinical trial that evaluated the efficacy and safety of EVT in patients with ASPECTS of 3-5. CT-ASPECTS was prioritized when both CT-ASPECTS and DWI-ASPECTS were measured. The effects of EVT on the modified Rankin Scale (mRS) score at 90 days were assessed separately for each stratum.

RESULTS

Among 183 patients, 112 (EVT group, 53; No-EVT group, 59) were in the CT-ASPECTS stratum and 71 (EVT group, 40; No-EVT group, 31) in the DWI-ASPECTS stratum. The common odds ratio (OR) (95% confidence interval) of the EVT group for one scale shift of the mRS score toward 0 was 1.29 (0.65-2.54) compared to the No-EVT group in CT-ASPECTS stratum, and 6.15 (2.46-16.3) in DWI-ASPECTS stratum with significant interaction between treatment assignment and mode of imaging study (P=0.002). There were significant interactions in the improvement of the National Institutes of Health Stroke Scale score at 48 hours (CT-ASPECTS stratum: OR, 1.95; DWIASPECTS stratum: OR, 14.5; interaction P=0.035) and mortality at 90 days (CT-ASPECTS stratum: OR, 2.07; DWI-ASPECTS stratum: OR, 0.23; interaction P=0.008).

CONCLUSION

Patients with ASPECTS of 3-5 on MRI benefitted more from EVT than those with ASPECTS of 3-5 on CT.

Differences in mechanical thrombectomy for acute ischemic stroke on weekdays versus nights/ weekends in a Japanese primary stroke core center

OBJECTIVE

The term "weekend effect" refers to an increase in the mortality rate for hospitalizations occurring on weekends versus weekdays. In this study, we investigated whether such an effect exists in patients undergoing mechanical thrombectomy for acute ischemic stroke with large vessel occlusion (currently the standard treatment for this condition) at a single center in Japan.

METHODS

We surveyed 151 patients who underwent mechanical thrombectomy for acute ischemic stroke with large vessel occlusion (75 and 76 patients were treated during daytime and nighttime, respectively) from January 2019 to June 2021. The items evaluated in this analysis were the rate of modified Rankin Scale ≤2 or prestroke scale, mortality, and procedural treatment time.

RESULTS

The rates of modified Rankin Scale ≤2 or prestroke scale and mortality at 90 days after treatment did not differ significantly between daytime and nighttime (41.3% vs. 29.0%, p=0.11; 14.7% vs. 11.8%, p=0.61, respectively). The door-to-groin time tended to be shorter during daytime versus nighttime (57 [IQR: 42.5-70] min vs. 70 [IQR: 55-82]) min, p=0.0507).

CONCLUSIONS

This study did not reveal differences in treatment outcome between daytime and nighttime in patients undergoing mechanical thrombectomy for acute ischemic stroke with large vessel occlusion. Therefore, the "weekend effect" was not observed in our institution.

Endovascular Therapy for Acute Stroke: New Evidence and Indications

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

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

BACKGROUND AND OBJECTIVES

There is growing evidence for endovascular thrombectomy (EVT) in patients with large ischemic core infarct and large vessel occlusion (LVO). The objective of this study was to compare the efficacy and safety of EVT vs medical management (MM) using a systematic review and meta-analysis of observational studies and randomized controlled trials (RCTs).

METHODS

We searched the PubMed, Embase, Cochrane Library, and Web of Science databases to obtain articles related to mechanical thrombectomy for large ischemic core from inception until February 10, 2023. The primary outcome was independent ambulation (modified Rankin Scale [mRS] 0-3). Effect sizes were computed as risk ratio (RR) with random-effect or fixed-effect models. The quality of articles was evaluated through the Cochrane risk assessment tool and the Newcastle-Ottawa Scale. This study was registered in PROSPERO (CRD42023396232).

RESULTS

A total of 5,395 articles were obtained through the search and articles that did not meet the inclusion criteria were excluded by review of the title, abstract, and full text. Finally, 3 RCTs and 10 cohort studies met the inclusion criteria. The RCT analysis showed that EVT improved the 90-day functional outcomes of patients with large ischemic core with high-quality evidence, including independent ambulation (mRS 0-3: RR 1.78, 95% CI 1.28-2.48, p < 0.001) and functional independence (mRS 0-2: RR 2.59, 95% CI 1.89-3.57, p < 0.001), but without significantly increasing the risk of symptomatic intracranial hemorrhage (sICH: RR 1.83, 95% CI 0.95-3.55, p = 0.07) or early mortality (RR 0.95, 95% CI 0.78-1.16, p = 0.61). Analysis of the cohort studies showed that EVT improved functional outcomes of patients without an increase in the incidence in sICH.

DISCUSSION

This systematic review and meta-analysis indicates that in patients with LVO stroke with a large ischemic core, EVT was associated with improved functional outcomes over MM without increasing sICH risk. The results of ongoing RCTs may provide further insight in this patient population.

Parenchymal Blood Volume Changes Immediately After Endovascular Thrombectomy Predict Futile Recanalization in Patients with Emergent Large Vessel Occlusion

OBJECTIVE

More than one third of acute ischemic stroke (AIS) patients do not recover to functional independence even if endovascular thrombectomy (EVT) is performed rapidly and successfully. This suggests that angiographic recanalization does not necessarily lead to tissue reperfusion. Although recognition of reperfusion status after EVT is pivotal for optimal postoperative management, reperfusion imaging assessment immediately after recanalization has not been fully investigated. The present study aimed to evaluate whether reperfusion status based on parenchymal blood volume (PBV) assessment after angiographic recanalization influences infarct growth and functional outcome in patients who have undergone EVT following AIS.

METHODS

Seventy-nine patients who underwent successful EVT for AIS were retrospectively analyzed. PBV maps were acquired from flat-panel detector computed tomography (CT) perfusion images before and after angiographic recanalization. Reperfusion status was assessed from PBV values and their changes in regions of interest and collateral score.

RESULTS

Post-EVT PBV ratio and ΔPBV ratio, as PBV parameters indicating the degree of reperfusion, were significantly lower in the unfavorable prognosis group (P < 0.01 each). Poor reperfusion on PBV mapping was associated with significantly longer puncture-to-recanalization time, lower collateral score, and higher frequency of infarct growth. Logistic regression analysis identified low collateral score and low ΔPBV ratio as associated with poor prognosis after EVT (odds ratios, 2.48, 3.72; 95% confidence intervals, 1.06-5.81, 1.20-11.53; P = 0.04, 0.02, respectively).

CONCLUSIONS

Poor reperfusion in severely hypoperfused territories on PBV mapping immediately after recanalization may predict infarct growth and unfavorable prognosis in patients who undergo EVT following AIS.

Tmax Mismatch Ratio to Identify Intracranial Atherosclerotic Stenosis-Related Large-Vessel Occlusion Before Endovascular Therapy

Background We aimed to clarify which time-to-maximum of the tissue residue function (Tmax) mismatch ratio is useful in predicting anterior intracranial atherosclerotic stenosis (ICAS)-related large-vessel occlusion (LVO) before endovascular therapy. Methods and Results Patients with ischemic stroke who underwent perfusion-weighted imaging before endovascular therapy for anterior intracranial LVO were divided into those with ICAS-related LVO and those with embolic LVO. Tmax ratios of >10 s/>8 s, >10 s/>6 s, >10 s/>4 s, >8 s/>6 s, >8 s/>4 s, and >6 s/>4 s were considered Tmax mismatch ratios. Binominal logistic regression was used to identify ICAS-related LVO, and the adjusted odds ratio (aOR) and 95% CI for each Tmax mismatch ratio increase of 0.1 were calculated. A similar analysis was performed for ICAS-related LVO with and without embolic sources, using embolic LVO as the reference. Of 213 patients (90 women [42.0%]; median age, 79 years), 39 (18.3%) had ICAS-related LVO. The aOR (95% CI) per 0.1 increase in Tmax mismatch ratio in ICAS-related LVO with embolic LVO as reference was lowest with Tmax mismatch ratio >10 s/>6 s (0.56 [0.43-0.73]). Multinomial logistic regression analysis also showed the lowest aOR (95% CI) per 0.1 increase in Tmax mismatch ratio with Tmax >10 s/>6 s (ICAS-related LVO without embolic source: 0.60 [0.42-0.85]; ICAS-related LVO with embolic source: 0.55 [0.38-0.79]). Conclusions A Tmax mismatch ratio of >10 s/>6 s was the optimal predictor of ICAS-related LVO compared with other Tmax profiles, with or without an embolic source before endovascular therapy. Registration clinicaltrials.gov. Identifier NCT02251665.

A systematic review and synthesis of global stroke guidelines on behalf of the World Stroke Organization

BACKGROUND

There are multiple stroke guidelines globally. To synthesize these and summarize what existing stroke guidelines recommend about the management of people with stroke, the World Stroke Organization (WSO) Guideline committee, under the auspices of the WSO, reviewed available guidelines.

AIMS

To systematically review the literature to identify stroke guidelines (excluding primary stroke prevention and subarachnoid hemorrhage) since 1 January 2011, evaluate quality (The international Appraisal of Guidelines, Research and Evaluation (AGREE II)), tabulate strong recommendations, and judge applicability according to stroke care available (minimal, essential, advanced).

SUMMARY OF REVIEW

Searches identified 15,400 titles; 911 texts were retrieved, 200 publications scrutinized by the three subgroups (acute, secondary prevention, rehabilitation), and recommendations extracted from most recent version of relevant guidelines. For acute treatment, there were more guidelines about ischemic stroke than intracerebral hemorrhage; recommendations addressed pre-hospital, emergency, and acute hospital care. Strong recommendations were made for reperfusion therapies for acute ischemic stroke. For secondary prevention, strong recommendations included establishing etiological diagnosis; management of hypertension, weight, diabetes, lipids, and lifestyle modification; and for ischemic stroke, management of atrial fibrillation, valvular heart disease, left ventricular and atrial thrombi, patent foramen ovale, atherosclerotic extracranial large vessel disease, intracranial atherosclerotic disease, and antithrombotics in non-cardioembolic stroke. For rehabilitation, there were strong recommendations for organized stroke unit care, multidisciplinary rehabilitation, task-specific training, fitness training, and specific interventions for post-stroke impairments. Most recommendations were from high-income countries, and most did not consider comorbidity, resource implications, and implementation. Patient and public involvement was limited.

CONCLUSION

The review identified a number of areas of stroke care where there was strong consensus. However, there was extensive repetition and redundancy in guideline recommendations. Future guideline groups should consider closer collaboration to improve efficiency, include more people with lived experience in the development process, consider comorbidity, and advise on implementation.

Impact of thrombocytopenia on hemorrhagic complications after endovascular therapy for acute large vessel occlusion: Sub-analysis of RESCUE-Japan registry 2

BACKGROUND

Endovascular treatment (EVT) for patients with large vessel occlusion (LVO) and concurrent thrombocytopenia raises concerns about hemorrhagic complications. We examined the association between thrombocytopenia and clinical outcomes after EVT.

METHODS

This is a sub-analysis of the RESCUE-Japan Registry 2, a nationwide registry that enrolled 2420 consecutive acute LVO patients. We evaluated the clinical outcomes in patients who underwent EVT according to their platelet count on admission (Moderate/Severe, < 100 × 10⁹ /L; Mild, 100 to ≤150 × 10⁹/L; Normal, ≥ 150 × 10⁹/L). The outcomes included any and symptomatic intracranial hemorrhage (ICH) after EVT, and modified Rankin Scale (mRS) at 90 days.

RESULTS

Of 1268 patients who underwent EVT, the Moderate/Severe and Mild groups consisted of 41 (3.2%), and 193 (15.2%) patients. Any ICH occurred in 37%, 35%, and 24% of Moderate/Severe, Mild, and Normal group patients, respectively, and the adjusted ORs (95% CIs) were 1.50 (0.71-3.18) for Moderate/Severe and 1.87 (1.28-2.73) for Mild, compared to the Normal group (p for trend = 0.004). Symptomatic ICH increased with the severity of thrombocytopenia (9.8% vs 3.6% vs 2.1%), and adjusted ORs were 4.43 (1.16-17.0) in Moderate/Severe and 1.85 (0.71-4.86) in Mild (p for trend = 0.10). Mortality was significantly associated with the severity of thrombocytopenia (p for trend = 0.005), and adjusted ORs were 3.26 (1.29-8.26) in the Moderate/Severe and 2.76 (1.58-4.84) in the Mild groups.

CONCLUSIONS

Thrombocytopenia in LVO patients was not rare and associated with the incidence and manifestation of ICH after EVT.

Safety outcomes of early initiation of antithrombotic agents within 24 h after intravenous alteplase at 0.6 mg/kg

BACKGROUND

We examined outcome of acute ischemic stroke (AIS) with administration of antithrombotics within 24 h after intravenous low-dose alteplase.

METHODS

Consecutive AIS patients who were treated with intravenous alteplase at 0.6 mg/kg from 2005 to 2021 were retrospectively included in our single-center registry. Patients were classified into two groups: those who received antithrombotics within 24 h after intravenous alteplase (early initiation group) and those who did not (control group). Safety outcomes were any intracranial hemorrhage (ICH), symptomatic ICH (sICH) within 36 h after onset, and death within 3 months. sICH was defined as any ICH with a ≥ 4-point increase in the National Institutes of Health Stroke Scale (NIHSS) score or death within 36 h.

RESULTS

Of 1111 patients (women, 426; median age, 76 [interquartile range, 69-83] years; median NIHSS score, 11 [6-19]; cardioembolism, 580 [52.2%]), early initiation group comprised 58 patients (22; 72 [65-80] years; 7 [4-12]; 11 [19.0%]) and control group comprised 1053 patients (404; 77 [69-84] years; 11 [6-19]; 569 [54.1%]). No significant between-group differences were observed in the incidence of any ICH (17.2% vs. 21.6%; adjusted odds ratio [aOR], 1.18; 95% confidence interval [CI], 0.57-2.44), sICH (0% vs. 0.9%, P = 1.00), or death within 3 months (5.2% vs. 6.7%; aOR, 1.23; 95% CI, 0.36-4.23).

CONCLUSIONS

Early initiation of antithrombotics after intravenous alteplase at 0.6 mg/kg did not increase the rate of sICH or death within 3 months and may be used with caution in patients with advanced neurological deterioration.

Mechanical Thrombectomy for Acute Common Carotid Artery Occlusion

Mechanical thrombectomy (MT) is the standard treatment for acute large occlusion of the cerebral artery. Evidence for the success of this procedure was based on the treatment of patients with internal carotid artery and middle cerebral artery thrombi. There are a few reports on thrombi extending to the common carotid artery (CCA). We document our endovascular procedure and the clinical outcome in seven consecutive patients who underwent MT for CCA thrombi between September 2016 and April 2021. Their mean National Institutes of Health Stroke Scale score was 20.0 (range, 9-30), and the mean diffusion-weighted imaging Alberta Stroke Program Early Computed Tomography Score on magnetic resonance images was 8.7 (range, 7-10). In six patients, MT of the CCA occlusion was successful, and the mean puncture-to-reperfusion time was 84 minutes (range, 39-211 minutes). In five patients, successful reperfusion was obtained. The mean total pass number was 4.1 (range, 2-7). Due to large thrombi, we performed balloon guide catheter (BGC) occlusion in three patients. Sheath occlusion occurred in two, and thrombus migration into the femoral artery around the sheath was observed in two patients. The mean modified Rankin Scale score 3 months post-stroke was 3.6 (range, 2-5). When the removal of a large CCA thrombus is attempted in a single step, catheter and sheath occlusion may occur, and this increases the risk for critical systemic artery occlusion. Therefore, we suggest that MT be combined with the BGC technique and propose the use of a large aspiration catheter to decrease the volume of the thrombus.

Endovascular vs Medical Management for Late Anterior Large Vessel Occlusion With Prestroke Disability: Analysis of CLEAR and RESCUE-Japan

BACKGROUND AND OBJECTIVES

Current guidelines do not address recommendations for mechanical thrombectomy (MT) in the extended time window (>6 hours after time last seen well [TLSW]) for large vessel occlusion (LVO) patients with preexisting modified Rankin Scale (mRS) > 1. In this study, we evaluated the outcomes of MT vs medical management in patients with prestroke disability presenting in the 6- to 24-hour time window with acute LVO.

METHODS

We analyzed a multinational cohort (61 sites, 6 countries from 2014 to 2020) of patients with prestroke (or baseline) mRS 2 to 4 and anterior circulation LVO treated 6-24 hours from TLSW. Patients treated in the extended time window with MT vs medical management were compared using multivariable logistic regression and inverse probability of treatment weighting (IPTW). The primary outcome was the return of Rankin (ROR, return to prestroke mRS by 90 days).

RESULTS

Of 554 included patients (448 who underwent MT), the median age was 82 years (interquartile range [IQR] 72-87) and the National Institutes of Health Stroke Scale (NIHSS) was 18 (IQR 13-22). In both MV logistic regression and IPTW analysis, MT was associated with higher odds of ROR (adjusted OR [aOR] 3.96, 95% CI 1.78-8.79 and OR 3.10, 95% CI 1.20-7.98, respectively). Among other factors, premorbid mRS 4 was associated with higher odds of ROR (aOR, 3.68, 95% CI 1.97-6.87), while increasing NIHSS (aOR 0.90, 95% CI 0.86-0.94) and decreasing Alberta Stroke Program Early Computed Tomography Scale score (aOR per point 0.86, 95% CI 0.75-0.99) were associated with lower odds of ROR. Age, intravenous thrombolysis, and occlusion location were not associated with ROR.

DISCUSSION

In patients with preexisting disability presenting in the 6- to 24-hour time window, MT is associated with a higher probability of returning to baseline function compared with medical management.

CLASSIFICATION OF EVIDENCE

This investigation's results provide Class III evidence that in patients with preexisting disability presenting 6-24 hours from the TLSW and acute anterior LVO stroke, there may be a benefit of MT over medical management in returning to baseline function.

Neuroimaging of Acute Ischemic Stroke: Multimodal Imaging Approach for Acute Endovascular Therapy

Advances in acute ischemic stroke (AIS) treatment have been contingent on innovations in neuroimaging. Neuroimaging plays a pivotal role in the diagnosis and prognosis of ischemic stroke and large vessel occlusion, enabling triage decisions in the emergent care of the stroke patient. Current imaging protocols for acute stroke are dependent on the available resources and clinicians' preferences and experiences. In addition, differential application of neuroimaging in medical decision-making, and the rapidly growing evidence to support varying paradigms have outpaced guideline-based recommendations for selecting patients to receive intravenous or endovascular treatment. In this review, we aimed to discuss the various imaging modalities and approaches used in the diagnosis and treatment of AIS.

Association Between Alberta Stroke Program Early Computed Tomography Score and Efficacy and Safety Outcomes With Endovascular Therapy in Patients With Stroke From Large-Vessel Occlusion: A Secondary Analysis of the Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Large Ischemic Core Trial (RESCUE-Japan LIMIT)

Importance

Endovascular therapy (EVT) has been found to reduce functional disability in patients with acute stroke due to large-vessel occlusion. However, the extent of the ischemic region, measured using Alberta Stroke Program Early Computed Tomography Scores, may limit the efficacy of EVT.

Objective

To compare the efficacy and safety of EVT according to ASPECTS 3 or less vs 4 to 5.

Design, Setting, and Participants

The Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Large Ischemic Core Trial (RESCUE-Japan LIMIT) was an open-label randomized clinical trial conducted from November 2018 to December 2021 at 45 stroke centers across Japan. The trial enrolled adult patients with acute ischemic stroke with a large ischemic region, defined as ASPECTS 3 to 5 primarily determined by magnetic resonance imaging, with occlusion site at the internal carotid artery or middle cerebral artery segment 1. Among 203 enrolled patients, 1 withdrew consent and 202 were included in the original trial and secondary analysis. This secondary analysis was conducted in April 2022.

Interventions

Patients were randomly assigned to EVT with medical therapy or medical therapy alone.

Main Outcomes and Measures

Modified Rankin Scale (mRS) score at 90 days and symptomatic and any intracranial hemorrhage within 48 hours.

Results

Among 202 patients, 106 (52%) had ASPECTS 3 or less (mean [SD] age, 76.7 [9.6] years; 54 female individuals [50.9%]) and 96 had ASPECTS 4 to 5 (mean [SD] age, 75.6 [10.6] years; 36 female individuals [37.5%]). Of patients with ASPECTS 3 or less, 12 (21.4%) in the EVT group and 9 (18.0%) in the no EVT group had an mRS score of 0 to 3 (odds ratio [OR], 1.24; 95% CI, 0.47-3.26). Of patients with ASPECTS 4 to 5, 19 patients (43.2%) in the EVT group and 4 (7.7%) in the no EVT group had an mRS score of 0 to 3 at 90 days (OR, 9.12; 95% CI, 2.80-29.70; interaction P = .01). The ordinal shift across the range of mRS scores toward a better outcome was not significant in those with ASPECTS or 3 or less (common OR, 1.56; 95% CI, 0.79-3.10) but was significant in those with ASPECTS 4 to 5 (common OR, 4.48; 95% CI, 2.07-9.71; interaction P = .046). The risk of intracranial hemorrhage was significantly increased in patients with ASPECTS 3 or less when EVT was conducted (OR, 4.14; 95% CI, 1.84-9.32) and nonsignificantly increased in those with ASPECTS 4 to 5 (OR, 2.05; 95% CI, 0.89-4.73; interaction P = .24).

Conclusions and Relevance

In this study, EVT was associated with improved 90-day functional outcomes in patients with acute large vessel occlusive stroke and ASPECTS was 4 to 5 but not in those with ASPECTS 3 or less.

Trial Registration

ClinicalTrials.gov Identifier: NCT03702413.

Intravenous Thrombolysis With Alteplase at 0.6 mg/kg in Patients With Ischemic Stroke Taking Direct Oral Anticoagulants

Background

We elucidated the safety of treatment with alteplase at 0.6 mg/kg within 24 hours for patients on direct oral anticoagulants (DOACs) before ischemic stroke onset.

Methods and Results

Consecutive patients with acute ischemic stroke who underwent intravenous thrombolysis using alteplase at 0.6 mg/kg from 2011 to 2021 were enrolled from our single‐center prospective stroke registry. We compared outcomes between patients taking DOACs and those not taking oral anticoagulants within 48 hours of stroke onset. The primary safety outcome was the rate of symptomatic intracranial hemorrhage with a ≥4‐point increase on the National Institutes of Health Stroke Scale score from baseline. The efficacy outcome was defined as 3‐month modified Rankin Scale score of 0 to 2 after stroke onset. Of 915 patients with acute ischemic stroke who received intravenous thrombolysis (358 women; median age, 76 years; median National Institutes of Health Stroke Scale score, 10), 40 patients took DOACs (6 took dabigatran, 8 took rivaroxaban, 16 took apixaban, and 10 took edoxaban) within 24 hours of onset and 753 patients did not take any oral anticoagulants. The rate of symptomatic intracranial hemorrhage was comparable between patients on DOACs and those not on oral anticoagulants (2.5% versus 2.4%, P=0.95). The rate of favorable outcomes was comparable between the 2 groups (59.4% versus 58.2%, P=0.46), although the admission National Institutes of Health Stroke Scale score was higher in patients on DOACs. No significant differences showed in any intracranial hemorrhage within 36 hours or mortality at 3 months.

Conclusions

Intravenous thrombolysis would be safely performed for patients on DOACs following the recommendations of the Japanese guidelines.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02251665.

Initial medical protocol efforts using both CT and MRI/MRA for acute cerebral infarction

BACKGROUND

Earlier administration of intravenous recombinant tissue-type plasminogen activator (rtPA) and mechanical thrombectomy (MT) improves the neurological prognosis of patients with acute ischemic stroke (AIS). We introduced a new protocol that includes head and chest computed tomography (CT) and magnetic resonance imaging (MRI)/ magnetic resonance angiography (MRA) for all patients, which is quite different from previously evaluated protocols. This study aimed to examine whether this protocol could contribute to the prompt therapeutic intervention of AIS.

METHODS

This is a retrospective observational study analyzing patients with AIS who were transported to our hospital by ambulance between January 2015 and November 2021. An AIS initial treatment protocol was introduced in April 2020, under which, CT and MRI/MRA imaging were performed in all patients, and the indication for rtPA and MT were determined. The participants were divided into those who were treated before and after the protocol introduction (conventional treatment and protocol groups, respectively). The time from hospital arrival to the start of rtPA administration (door-to-needle time: DNT) and the time from hospital arrival to the start of endovascular treatment (door-to-puncture time: DPT) were compared between the groups.

RESULT

A total of 121 patients were analyzed, wherein 63 patients received rtPA (18 in the conventional treatment group and 45 in the protocol group) and 98 patients received MT (32 in the conventional treatment group and 66 in the protocol group). The median DNT was 97.0 (IQR 49.0-138.0) min vs. 56.5 (IQR 41.0-72.0) min (p < 0.001) for the conventional treatment and the protocol groups, respectively. The median DPT was 129.0 (IQR 62.0-196.0) min vs. 55.0 (IQR 40.5-69.5) min (p < 0.001), respectively. Moreover, DNT was achieved within 60 min in 5.6% vs. 69.9% (p < 0.001) and DPT within 90 min in 25.0% vs. 85.7% (p < 0.001), respectively.

CONCLUSION

The introduction of a protocol, including CT/MRI imaging, significantly shortened DNT and DPT.

Neurointerventional tools and techniques for coronary thrombus removal. A case-based review

Due to the negative results of randomized aspiration thrombectomy studies, its role in myocardial infarction has been limited to high thrombus burden and/or failed vessel recanalization, with little technological advancement over the last years. In contrast, there has been rapid progress in mechanical thrombectomy in stroke, which is understandable as most ischemic cerebrovascular accidents have an embolic etiology.We present three transradial procedures wherein neurointerventional catheters were used as a first-line device for en bloc removal of large clots lodged distally in tortuous coronary anatomy. First-pass reperfusion was achieved in all the cases, without dissection, distal embolization, or the no reflow phenomenon.

Learning objective

In the case of large clots, where coronary aspiration devices fail, neurointerventional catheters may be considered as a rescue strategy. They provide large aspiration lumen and excellent trackability with atraumatic design. Many other neurointerventional techniques can be easily adopted into the coronary armamentarium, possibly increasing the safety and efficacy of thrombus aspiration.

Impact on Clinical Outcomes of Changes in the Practice of Mechanical Thrombectomy due to the COVID-19 Pandemic

Objective

To evaluate whether changes in the practice of mechanical thrombectomy could affect the clinical outcomes during the coronavirus disease (COVID-19) pandemic.

Methods

Patients who underwent mechanical thrombectomy from April 2019 to March 2021 for anterior circulation proximal large artery occlusion in our institute were divided into two groups of pre- and post-COVID-19, with April 2020 assumed to be the start of the COVID-19 era with the first declaration of a state of emergency. We compared patient characteristics, proportions of patient selection depending on rapid processing of perfusion and diffusion (RAPID) CT perfusion, outcomes including treatment variables such as time and reperfusion status, and patient independence at 3 months.

Results

Data for 112 patients (median age, 79 years; 44 females) were included in the analysis. A total of 50 patients were assigned to the pre-COVID-19 group (45%). More patients were selected with RAPID CT perfusion in the post-COVID-19 compared with the pre-COVID-19 (69% vs. 16%; P <0.001). Treatment details and clinical outcomes did not differ between the groups, including the door-to-puncture time (median [interquartile range], 66 [54-90] min vs. 74 [61-89] min; P = 0.15), proportions of significant reperfusion (82% vs. 87%; P = 0.60), and modified Rankin scale score of ≤2 at 3 months (46% vs. 45%; P >0.99). Multivariate logistic regression analysis for the clinical outcome of modified Rankin scale score of ≤2 at 3 months was performed and included the following factors: age, sex, the onset-to-door time, significant reperfusion, and pre- and post-COVID-19. The treatment period did not influence the outcomes (post-COVID-19 group, odds ratio, 0.79; 95% confidence interval, 0.34-1.85, P = 0.59).

Conclusion

In the setting of a limited access to emergency MRI during the COVID-19 pandemic, RAPID CT perfusion was performed significantly more often. Changes in the practice of mechanical thrombectomy with the protected code stroke did not bring the different level of treatment and clinical outcomes as before.

Endovascular Therapy for Acute Stroke with a Large Ischemic Region

BACKGROUND

Endovascular therapy for acute ischemic stroke is generally avoided when the infarction is large, but the effect of endovascular therapy with medical care as compared with medical care alone for large strokes has not been well studied.

METHODS

We conducted a multicenter, open-label, randomized clinical trial in Japan involving patients with occlusion of large cerebral vessels and sizable strokes on imaging, as indicated by an Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) value of 3 to 5 (on a scale from 0 to 10, with lower values indicating larger infarction). Patients were randomly assigned in a 1:1 ratio to receive endovascular therapy with medical care or medical care alone within 6 hours after they were last known to be well or within 24 hours if there was no early change on fluid-attenuated inversion recovery images. Alteplase (0.6 mg per kilogram of body weight) was used when appropriate in both groups. The primary outcome was a modified Rankin scale score of 0 to 3 (on a scale from 0 to 6, with higher scores indicating greater disability) at 90 days. Secondary outcomes included a shift across the range of modified Rankin scale scores toward a better outcome at 90 days and an improvement of at least 8 points in the National Institutes of Health Stroke Scale (NIHSS) score (range, 0 to 42, with higher scores indicating greater deficit) at 48 hours.

RESULTS

A total of 203 patients underwent randomization; 101 patients were assigned to the endovascular-therapy group and 102 to the medical-care group. Approximately 27% of patients in each group received alteplase. The percentage of patients with a modified Rankin scale score of 0 to 3 at 90 days was 31.0% in the endovascular-therapy group and 12.7% in the medical-care group (relative risk, 2.43; 95% confidence interval [CI], 1.35 to 4.37; P = 0.002). The ordinal shift across the range of modified Rankin scale scores generally favored endovascular therapy. An improvement of at least 8 points on the NIHSS score at 48 hours was observed in 31.0% of the patients in the endovascular-therapy group and 8.8% of those in the medical-care group (relative risk, 3.51; 95% CI, 1.76 to 7.00), and any intracranial hemorrhage occurred in 58.0% and 31.4%, respectively (P<0.001).

CONCLUSIONS

In a trial conducted in Japan, patients with large cerebral infarctions had better functional outcomes with endovascular therapy than with medical care alone but had more intracranial hemorrhages. (Funded by Mihara Cerebrovascular Disorder Research Promotion Fund and the Japanese Society for Neuroendovascular Therapy; RESCUE-Japan LIMIT ClinicalTrials.gov number, NCT03702413.).

Randomized Clinical Trial of Endovascular Therapy for Acute Large Vessel Occlusion with Large Ischemic Core (RESCUE-Japan LIMIT): Rationale and Study Protocol

Endovascular therapy is strongly recommended for acute cerebral large vessel occlusion (LVO) with an Alberta stroke program early computed tomography score (ASPECTS) ≥6 due to occlusion of the internal carotid artery or M1 segment of the middle cerebral artery. However, the effect of endovascular therapy for patients with a large ischemic core with an ASPECTS ≤5 (0-5) was not established. A multicenter, randomized, open-label, parallel-group trial was conducted to investigate the superiority of endovascular therapy over medical therapy without endovascular therapy for a large ischemic core with ASPECTS (3-5). Patients were randomly assigned to receive endovascular therapy or without endovascular therapy at a ratio of 1:1. The primary outcome was a moderate functional outcome, defined as a modified Rankin scale (mRS; scores ranging from 0 [no symptoms] to 6 [death]) ≤3 after 90 days. The secondary outcomes were defined as ordinal mRS, good functional outcome (mRS ≤2), excellent functional outcome (mRS ≤1), mRS shift analysis after 90 days, and early improvement of neurological findings at 48 hours. A total sample size of 200 was estimated to provide a power of 0.9 with a two-sided alpha of 0.05, for the primary outcome, considering a 15% dropout rate. This randomized clinical trial reported the applicability of endovascular therapy in patients with acute cerebral LVO with a large ischemic core.

Clinical Imaging of the Penumbra in Ischemic Stroke: From the Concept to the Era of Mechanical Thrombectomy

The ischemic penumbra is defined as the severely hypoperfused, functionally impaired, at-risk but not yet infarcted tissue that will be progressively recruited into the infarct core. Early reperfusion aims to save the ischemic penumbra by preventing infarct core expansion and is the mainstay of acute ischemic stroke therapy. Intravenous thrombolysis and mechanical thrombectomy for selected patients with large vessel occlusion has been shown to improve functional outcome. Given the varying speed of infarct core progression among individuals, a therapeutic window tailored to each patient has recently been proposed. Recent studies have demonstrated that reperfusion therapies are beneficial in patients with a persistent ischemic penumbra, beyond conventional time windows. As a result, mapping the penumbra has become crucial in emergency settings for guiding personalized therapy. The penumbra was first characterized as an area with a reduced cerebral blood flow, increased oxygen extraction fraction and preserved cerebral metabolic rate of oxygen using positron emission tomography (PET) with radiolabeled O₂. Because this imaging method is not feasible in an acute clinical setting, the magnetic resonance imaging (MRI) mismatch between perfusion-weighted imaging and diffusion-weighted imaging, as well as computed tomography perfusion have been proposed as surrogate markers to identify the penumbra in acute ischemic stroke patients. Transversal studies comparing PET and MRI or using longitudinal assessment of a limited sample of patients have been used to define perfusion thresholds. However, in the era of mechanical thrombectomy, these thresholds are debatable. Using various MRI methods, the original penumbra definition has recently gained a significant interest. The aim of this review is to provide an overview of the evolution of the ischemic penumbra imaging methods, including their respective strengths and limitations, as well as to map the current intellectual structure of the field using bibliometric analysis and explore future directions.

Influence of hospital capabilities and prehospital time on outcomes of thrombectomy for stroke in Japan from 2013 to 2016

To determine whether increasing thrombectomy-capable hospitals with moderate comprehensive stroke center (CSC) capabilities is a valid alternative to centralization of those with high CSC capabilities. This retrospective, nationwide, observational study used data from the J-ASPECT database linked to national emergency medical service (EMS) records, captured during 2013–2016. We compared the influence of mechanical thrombectomy (MT) use, the CSC score, and the total EMS response time on the modified Rankin Scale score at discharge among patients with acute ischemic stroke transported by ambulance, in phases I (2013–2014, 1461 patients) and II (2015–2016, 3259 patients). We used ordinal logistic regression analyses to analyze outcomes. From phase I to II, MTs increased from 2.7 to 5.5%, and full-time endovascular physicians per hospital decreased. The CSC score and EMS response time remained unchanged. In phase I, higher CSC scores were associated with better outcomes (1-point increase, odds ratio [95% confidence interval]: 0.951 [0.915–0.989]) and longer EMS response time was associated with worse outcomes (1-min increase, 1.007 [1.001–1.013]). In phase II, neither influenced the outcomes. During the transitional shortage of thrombectomy-capable hospitals, increasing hospitals with moderate CSC scores may increase nationwide access to MT, improving outcomes.

Mechanical Thrombectomy Up to 24 Hours in Large Vessel Occlusions and Infarct Velocity Assessment

Background

We retrospectively compared early‐ (<6 hours) versus late‐ (6–24 hours) presenting patients using perfusion‐weighted imaging selection and evaluated clinical/radiographic outcomes.

Methods and Results

Large vessel occlusion patients treated with mechanical thrombectomy from August 2017 to July 2020 within 24 hours of onset were retrieved from a single‐center database. Perfusion‐weighted imaging was analyzed by automated software and final infarct volume was measured semi‐automatically within 14 days. The primary end point was good outcome (modified Rankin Scale 0–2 at 90 days). Secondary end points were excellent outcome (modified Rankin Scale 0–1 at 90 days), symptomatic intracranial hemorrhage, and death. Clinical characteristics/radiological values including hypoperfusion volume and infarct growth velocity (baseline volume/onset‐to‐image time) were compared between the groups. Of 1294 patients, 118 patients were included. The median age was 74 years, baseline National Institutes of Health Stroke Scale score was 14, and core volume was 13 mL. The late‐presenting group had more female patients (67% versus 31%, respectively; P=0.001). No statistically significant differences were seen in good outcome (42% versus 53%, respectively; P=0.30), excellent outcome (26% versus 32%, respectively; P=0.51), symptomatic intracranial hemorrhage (6.5% versus 4.6%, respectively; P=0.74), and death (3.2% versus 5.7%, respectively; P=0.58) between the groups. The late‐presenting group had more atherothrombotic cerebral infarction (19% versus 6%, respectively; P=0.03), smaller hypoperfusion volume (median: 77 versus 133 mL, respectively; P=0.04), and slower infarct growth velocity (median: 0.6 versus 5.1 mL/h, respectively; P=0.03).

Conclusions

Patients with early‐ and late‐time windows treated with mechanical thrombectomy by automated perfusion‐weighted imaging selection have similar outcomes, comparable with those in randomized trials, but different in infarct growth velocities.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02251665.

Delays in Presentation Time Under the COVID-19 Epidemic in Patients With Transient Ischemic Attack and Mild Stroke: A Retrospective Study of Three Hospitals in a Japanese Prefecture

Background: Coronavirus Disease 2019 (COVID-19) has spread worldwide with collateral damage and therefore might affect the behavior of stroke patients with mild symptoms seeking medical attention.

Methods: Patients with ischemic stroke who were admitted to hospitals within 7 days of onset were retrospectively registered. The clinical characteristics, including onset-to-door time (ODT), of patients with a transient ischemic attack (TIA)/mild stroke (National Institutes of Health Stroke Scale [NIHSS] score of ≤ 3 on admission) or moderate/severe stroke were compared between those admitted from April 2019 to March 2020 (pre-COVID-19 period) and from April to September 2020 (COVID-19 period). Multivariable regression analysis was performed to identify factors associated with the ODT.

Results: Of 1,100 patients (732 men, median age, 73 years), 754 were admitted during the pre-COVID-19 period, and 346 were admitted during the COVID-19 period. The number and proportion of patients with TIA/minor stroke were 464 (61.5%) in the pre-COVID-19 period and 216 (62.4%) during the COVID-19 period. Among patients with TIA/mild stroke, the ODT was longer in patients admitted during the COVID-19 period compared with that of the pre-COVID-19 period (median 864 min vs. 508 min, p = 0.003). Multivariable analysis revealed the COVID-19 period of admission was associated with longer ODT (standardized partial regression coefficient 0.09, p = 0.003) after adjustment for age, sex, route of arrival, NIHSS score on admission, and the presence of hypertension, diabetes mellitus, and wake-up stroke. No significant change in the ODT was seen in patients with moderate/severe stroke.

Conclusions: The COVID-19 epidemic might increase the ODT of patients with TIA/mild stroke.

Evaluation of Workflow Delays in Stroke Reperfusion Therapy: A Comparison between the Year-Long Pre-COVID-19 Period and the with-COVID-19 Period

Aim: We evaluated the delay in stroke reperfusion therapy between the pre-coronavirus disease 2019 (COVID-19) period and the with-COVID-19 period, and compared this delay between each phase of the with-COVID-19 period.

Methods: Patients with acute ischemic stroke (AIS) undergoing intravenous thrombolysis and/or mechanical thrombectomy were selected from our single-center prospective registry. The time to perform reperfusion therapy were compared between patients admitted from March 2019 to February 2020 (pre-COVID-19 group) and those from March 2020 to February 2021 (with-COVID-19 group). Patients in the with-COVID-19 group were further divided into three 4-month-long subgroups (first-phase: March to June 2020; second-phase: July to October 2020; third-phase: November 2020 to February 2021), and the time delay of reperfusion therapy were compared between these subgroups.

Results: Of 1,260 patients with AIS hospitalized in the study period, 265 patients were examined. Compared with the pre-COVID-19 group (133 patients; median age, 79 years), the with-COVID-19 group (132 patients; median age, 79 years) had a longer median door-to-imaging time (25 min vs. 27 min,P=0.04), and a longer door-to-groin puncture time (65 min vs. 72 min,P=0.02). In the three 4-month-long subgroups, the median door-to-needle time (49 min, 43 min, and 38 min, respectively;P=0.04) and door-to-groin puncture time (83 min, 70 min, and 61 min,P＜0.01, respectively) decreased significantly during the with-COVID-19 period.

Conclusions: The delay in reperfusion therapy increased during the with-COVID-19 period compared with the pre-COVID-19 period. However, the door-to-needle time and door-to-groin puncture time decreased as time elapsed during the with-COVID-19 period.

ClinicalTrials.gov Identifier: NCT02251665