Contact aspiration for basilar artery occlusion safely reduces the puncture-to-recanalization time.

OBJECTIVE: Effective thrombectomies in the posterior circulation remain controversial. Previous reports have demonstrated the superiority of contact aspiration in anterior circulation. Aspiration catheters and stent retrievers are often used alone on a global scale, while combined techniques are commonly used in Japan. This study evaluated the effect of first-line contact aspiration with other strategies for the treatment of basilar artery occlusion. METHODS: The primary outcome was the frequency of the first-pass effect, and the secondary outcome was the time from puncture to the first-pass effect. A multicenter observational registry including 16 Japanese stroke centers was used. Between December 2013 and February 2021, enrolled patients underwent endovascular thrombectomy for basilar artery occlusion. The efficacy of contact aspiration compared to other methods (including stent retrievers and combined techniques) was evaluated. RESULTS: Eighty-four patients were included, all of whom had achieved effective recanalization. Twenty-six patients were treated with contact aspiration, 13 with combined technique, and 45 with stent retrievers. The two groups: contact aspiration and non-contact aspiration, had different backgrounds. Both had similar frequencies of effective recanalization and first-pass effects. The contact aspiration group experienced better functional outcomes without statistical significance, while this strategy was significantly associated with a shorter puncture-to-recanalization time (38 vs. 55 minutes, P=0.036). In particular, in the 55 patients with the first-pass effect, multivariate Cox proportional hazard analysis showed that contact aspiration was significantly associated with a shorter time from puncture to first-pass effect, independent of age and etiology of large-artery atherosclerosis (hazard ratio 2.02, 95% confidence intervals 1.10-3.69, P=0.023). CONCLUSION: This study suggested that contact aspiration for basilar artery occlusion may shorten the puncture-to-first-pass effect, compared to stent retrievers and combined techniques.

Impact of cancer history on long-term outcome after elective neuro-endovascular treatment in patients aged 80 years or older: A retrospective multicenter observational study.

AIM: Assessing the indication for elective neuro-endovascular treatment (EVT) in older patients requires consideration of the impact of systemic comorbidities on their overall reduced life expectancy. The objective of this study was to determine the long-term outcomes of elective neuro-EVT in patients aged ≥80 years, and to investigate the impact of pre-existing cancer on their long-term outcomes. METHODS: Of the patients enrolled in multicenter observational registry, those aged ≥80 years undergoing elective neuro-EVT between 2011 and 2020 were enrolled. A history of cancer was defined as a pre-existing solid or hematologic malignancy at the time of EVT. The primary outcome was time to death from elective neuro-EVT. RESULTS: Of the 6183 neuro-EVT cases implemented at 10 stroke centers, a total of 289 patients (median age, 82 years [interquartile range 81-84 years]) were analyzed. A total of 58 (20.1%) patients had a history of cancer. A total of 78 patients (27.0%) died during follow up. The 5-year survival rate of enrolled patients was 64.6%. Compared with patients without a history of cancer, those with a history of cancer showed significantly worse survival (log-rank test, P = 0.001). Multivariate Cox proportional hazards analysis showed history of cancer was an independent predictor of time to death from elective neuro-EVT (HR 1.74, 95% CI 1.01-3.00, P = 0.047). Cancer was the leading cause of death, accounting for 25.6% of all deaths. CONCLUSIONS: The present study showed that history of cancer has a significant impact on time to death from elective neuro-EVT in patients aged ≥80 years. Geriatr Gerontol Int 2024; 24: 211-217.

The impact of SAH finding on CT to the clinical outcome after mechanical thrombectomy for large vessel occlusion.

BACKGROUND AND PURPOSE: Whether subarachnoid haemorrhage (SAH) after mechanical thrombectomy affects the clinical outcomes of patients with acute large-vessel occlusion remains unclear. This study aimed to investigate the clinical impact of SAH on computed tomography (CT) after mechanical thrombectomy. METHODS: The SKIP study was an investigator-initiated, multicentre, randomised, open-label clinical trial. This study was performed in 23 hospital networks in Japan from January 1, 2017, to July 31, 2019. Among the 204 patients, seven were excluded because they did not undergo mechanical thrombectomy (MT) and had a modified Rankin scale (mRS) score > 2. The main outcome was the association between SAH within 36 h after mechanical thrombectomy and the clinical outcome at 90 days. RESULTS: Among 197 patients, the median age was 74 (67-79) years, 62.9% were male. Moreover, 26 (13.2%) patients had SAH (seven isolated SAH) on CT within 36 h. The SAH rate did not differ according to IV rt-PA administration (p = 0.4). The rate of favourable clinical outcomes tended to be lower in patients with SAH rather than patients without SAH (11 [42%] vs. 106 [62%], p = 0.08). Among the seven patients with isolated SAH, 6 showed favourable outcomes at 90 days. In the multivariate regression analysis, the presence of SAH within 36 h from onset was not associated with clinical outcome (Odd ratio, 0.59; 95% confidence interval, 0.18-1.95; p = 0.38). CONCLUSIONS: Among patients with acute stroke treated with MT, SAH, especially isolated SAH findings on CT, were not associated with poor clinical outcomes after 90 days. TRIAL REGISTRATION NUMBER: UMIN000021488.

Ultra-early rt-PA administration should improve patient outcome on mechanical thrombectomy: Post hoc analysis of SKIP.

BACKGROUND: To investigate whether ultra-early recombinant tissue-plasminogen activator (rt-PA) administration can improve patient outcomes on mechanical thrombectomy (MT) in patients with large vessel occlusion (LVO). METHODS: Participants comprised rt-PA-eligible 204 patients with internal carotid artery or middle cerebral artery occlusion in the SKIP trial, who were randomly assigned to receive mechanical thrombectomy alone or combined intravenous thrombolysis (rt-PA: alteplase at 0.6 mg/kg) plus mechanical thrombectomy. We assessed associations between onset-to-puncture time and onset-to-rt-PA administration time and frequency of favorable outcome at 90 days and any intracerebral hemorrhage (ICH) at 36 h after onset. RESULTS: As a cut-off onset-to-puncture time for favorable outcome, receiver operating characteristic curves defined 2.5 h (57% sensitivity, 62% specificity). For onset-to-puncture times ≤2.5 h and > 2.5 h, frequencies of favorable outcomes were 72% and 63% (p = 0.402) in patients with rt-PA therapy and 44% and 58% (p = 0.212) in patients without rt-PA therapy, respectively. In terms of onset-to-rt-PA administration time, frequencies of favorable outcomes among patients with ultra-early rt-PA administration at ≤100, >100 min after onset, and without rt-PA therapy with onset-to-puncture time ≤ 2.5 h, and with and without rt-PA therapy with onset-to-puncture time > 2.5 h were 84% and 64%, 63%, and 44% and 58%, respectively (p = 0.025). Frequencies of any ICH among those patients were 37% and 32%, 32%, and 63% and 40%, respectively (p = 0.006). CONCLUSION: Ultra-early rt-PA administration should improve patient outcomes on mechanical thrombectomy among patients with LVO. Relatively late rt-PA administration might increase the frequency of any ICH.

Imaging predictors of clinical outcomes after endovascular treatment in MRI-selected patients with acute basilar artery occlusion.

PURPOSE: We aimed to investigate the impact of baseline infarct area and collateral status (CS), which are imaging predictors of clinical outcome following stroke, after endovascular treatment (EVT) in MRI-selected patients with acute basilar artery occlusion (BAO). METHODS: Patients with acute BAO who underwent EVT within 24 h after stroke from December 2013 to February 2021 were included in this retrospective, multicenter, observational study. The baseline infarct area was evaluated by the posterior circulation of Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS) using diffuse-weighted imaging (DWI), and CS was assessed by measuring the computed tomography angiography of the basilar artery (BATMAN) score and the posterior circulation collateral score (PC-CS) using magnetic resonance angiography (MRA). A Good outcome was defined as a modified Rankin scale score ≤ 3 at 3 months. For each imaging predictor, a multivariate logistic regression analysis was performed to evaluate its impact on good outcomes. RESULTS: A total of 86 patients were analyzed, and 37 (43.0%) had a good outcome. The latter showed significantly higher pc-ASPECTS than those without good outcomes. In multivariate analyses, a pc-ASPECTS ≥ 7 was significantly associated with good outcomes (OR, 2.98 [95% CI, 1.10-8.13], P = 0.032), while PC-CS ≥ 4 (OR, 2.49 [95% CI, 0.92-6.74], P = 0.073) and BATMAN score ≥ 5 (OR, 1.51 [95% CI, 0.58-3.98], P = 0.401) were not. CONCLUSIONS: In MRI-selected patients with acute BAO, pc-ASPECTS on DWI was an independent predictor of clinical outcomes after EVT, while the MRA-based CS assessments were not.

Influence of Bilateral Cerebellar Infarction on Functional Outcome After Endovascular Treatment for Basilar Artery Occlusion.

BACKGROUND AND PURPOSE: To measure the magnitude of the effect of the infarct location measured using the posterior circulation Alberta Stroke Program Early Computed Tomographic Score (pc-ASPECTS) on the functional outcome at 90 days in patients with basilar artery (BA) occlusion undergoing endovascular therapy (EVT). METHODS: Of the acute ischemic stroke patients undergoing EVT for acute posterior circulation large vessel occlusion enrolled in the multicenter observational registry from December 2013 to February 2021, patients with BA occlusion were included. A favorable outcome was defined as achieving a modified Rankin Scale score of 0-3 at 90 days. The effect of pc-ASPECTS including the distribution on favorable outcomes was evaluated. RESULTS: One hundred patients were analyzed. Fifty-one patients (51%) achieved favorable outcome. Patients achieving a favorable outcome were younger, had a lower National Institutes of Health Stroke Scale score before EVT, and had a higher pc-ASPECTS before EVT than those not achieving a favorable outcome. Multivariable logistic analysis showed a significant association between higher pc-ASPECTS and a favorable outcome (odds ratio [OR] 1.24; 95% confidence interval [CI] 1.02-1.52; P = 0.028). Considering the infarct location, bilateral cerebellar infarction was significantly associated with a lower frequency of favorable outcomes than those without cerebellar infarction (OR 0.16; 95% CI 0.04-0.51; P = 0.002). CONCLUSIONS: A higher pc-ASPECTS before EVT could be a predictor of a favorable outcome after EVT for BA occlusion. In particular, the presence of bilateral cerebellar infarction before EVT was significantly associated with a lower likelihood of a favorable outcome.

An Initial High National Institutes of Health Stroke Scale Score and Any Intracranial Hemorrhage Are Independent Factors for a Poor Outcome in Nonagenarians Treated with Thrombectomy for Acute Large Vessel Occlusion: The Tokyo/Tama-REgistry of Acute Endovascular Thrombectomy (TREAT) Study.

BACKGROUND: Mechanical thrombectomy (MT) is effective in acute ischemic stroke patients ≥80 years old with large vessel occlusion (LVO). However, data for patients ≥90 years old remain very limited, and factors influencing functional outcomes are unclear. This study aimed to investigate factors influencing functional outcomes in patients ≥90 years old treated with MT for acute LVO. METHODS: This retrospective observational study used prospectively collected data from the Tokyo/tama-REgistry of Acute endovascular Thrombectomy (TREAT) study. Inclusion criteria were as follows: 1) patients ≥90 years old treated with MT for LVO and 2) prestroke modified Rankin Scale (mRS) score, 0-3. The functional outcome was defined based on the mRS score at 90 days after the procedure: good functional outcome, mRS score 0-3 and poor functional outcome, mRS score 4-6. RESULTS: Data were analyzed for 104 patients ≥90 years old. The good functional outcome was observed in 25 patients (24.0%), and the poor functional outcome was observed in the remaining 79 patients. Significant differences were identified in initial National Institutes of Health Stroke Scale (NIHSS) score, modified Thrombolysis in Cerebral Infarction grade 2b-3, modified Thrombolysis in Cerebral Infarction grade 3, and any intracranial hemorrhage and hemorrhagic infarction in univariate analyses. Multivariable analysis confirmed the initial NIHSS score (odds ratio, 1.08; 95% confidence interval, 1.01-1.17; P = 0.045) and any intracranial hemorrhage (odds ratio, 11.6; 95% confidence interval, 1.43-95.0; P = 0.022) as independent factors for the functional outcome. CONCLUSIONS: An initial high NIHSS score and any intracranial hemorrhage are independent factors for the poor functional outcome in acute ischemic stroke patients ≥90 years old treated with MT.

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.).

Intravenous Alteplase is Associated with First Pass Effect in Stent-retriever but not ADAPT Thrombectomy : Post Hoc Analysis of the SKIP Study.

PURPOSE: To investigate the effect of alteplase, either combined with stent-retriever thrombectomy or a direct aspiration first pass technique (ADAPT), in patients with large-vessel occlusion stroke. METHODS: This was a retrospective post hoc analysis of data from The Direct Mechanical Thrombectomy in Acute LVO Stroke (SKIP) study. Patients were divided into two groups according to the first-line thrombectomy technique: stent-retriever and ADAPT. Each group was further divided into two subgroups, namely MT and MT + alteplase. The procedural outcomes, such as first pass effect (FPE) ratio and number of passes, were evaluated. The clinical outcomes included mRS score at 3 months. RESULTS: A total of 180 patients were included (116 in the stent-retriever group and 64 in the ADAPT group). No interaction was detected between the first-line technique and alteplase administration. In the stent-retriever group, after adjusting for factors associated with FPE, the adjusted odds ratio (95% confidence interval) of FPE of the MT + alteplase subgroup versus the MT subgroup was 3.57 (1.5-8.48) and in the ADAPT group it was 1.35 (0.37-4.91). With alteplase, the number of passes decreased with adjusted odds ratios of 0.59 (0.37-0.93) in the stent-retriever group but not in the ADAPT group. In both first-line technique groups, clinical outcomes did not differ between subgroups. CONCLUSION: In the SKIP study, alteplase administration was associated with increased FPE when combined with stent-retriever thrombectomy, but not with ADAPT. We found no differences in the clinical outcomes.

Impact of Coronavirus Disease 2019 on Time Delay and Functional Outcome of Mechanical Thrombectomy in Tokyo, Japan.

OBJECTIVES: An association has been reported between delays in the onset-to-door (O2D) time for mechanical thrombectomy (MT) and outbreaks of coronavirus disease 2019 (COVID-19). However, the association between other MT time courses or functional outcomes and COVID-19 outbreaks remains unclear. We compared the time courses of stroke pathways or functional outcomes in 2020 (the COVID-19 era) with those in 2019 (the pre-COVID-19 era) in Tokyo, Japan. MATERIALS AND METHODS: This retrospective observational study used data from the Tokyo-tama-REgistry of Acute endovascular Thrombectomy (TREAT), a multicenter registry of MT for acute large vessel occlusion in the Tokyo Metropolitan Area. Patients who had undergone acute MT from January 2019 to December 2020 were included. Patients were classified by the year they had undergone MT (2019 or 2020). RESULTS: In total, 477 patients were analyzed. O2D time was significantly longer in 2020 (146.0 min) than in 2019 (105.0 min; p = 0.034). No significant difference in door-to-puncture time (D2P) time or modified Rankin Scale (mRS) score 0-2 at 90 days was seen between 2019 and 2020. In the subgroup analysis, O2D time was significantly longer in the first half of 2020 compared with 2019. Multivariable logistic regression analysis revealed that the year 2020 was a independent predictor of longer O2D time, but not for mRS score 0-2 at 90 days. CONCLUSIONS: Although O2D time was significantly longer in the COVID-19 compared with the pre-COVID-19 era, D2P may not be significantly delayed and functional outcomes may not be different, despite the COVID-19 pandemic.

Endovascular treatment of acute basilar artery occlusion: Outcomes, influencing factors and imaging characteristics from the Tama-REgistry of acute thrombectomy (TREAT) study.

OBJECTIVE: The effectiveness of mechanical thrombectomy (MT) for acute basilar artery occlusion (ABAO) remains unknown. We evaluated the feasibility, safety, and efficacy of endovascular treatment for ABAO. METHODS: We retrospectively investigated patients with ABAO who underwent MT using modern stent retrievers and an aspiration device between January 2015 and March 2019 at 12 comprehensive stroke centers. Functional outcomes and 90-day mortality rates were analyzed as primary outcomes. Factors influencing outcomes were analyzed as secondary outcomes. Relationships between outcome and affected area of infarction on arrival were also analyzed. RESULTS: Seventy-three patients were included. Good outcome (modified Rankin Scale (mRS) score 0-2) was achieved in 25/73 patients (34.2%) and the all-cause 90-day mortality rate was 23.3% (17/73). Successful recanalization (modified Thrombolysis In Cerebral Infarction grade 2b and 3) was achieved in 70/73 patients (95.9%). In univariate analyses, age, National Institutes of Health Stroke Scale score, and posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) differed significantly between good and poor functional outcome groups. Age and pc-ASPECTS were significantly associated with functional outcomes in the logistic regression model. Positive findings for the midbrain on diffusion-weighted imaging on pc-ASPECTS and brainstem score were significantly associated with poor outcomes. CONCLUSION: MT with modern devices for ABAO resulted in highly successful recanalization and good outcomes. A positive finding for the midbrain on initial imaging might predict poor outcomes. Further studies are required to confirm our results.

Outcomes of Large Vessel Occlusion Stroke in Patients Aged ≥90 Years.

BACKGROUND AND PURPOSE: Outcomes in patients ≥90 years of age with stroke due to large vessel occlusion were compared between endovascular therapy (EVT) and medical management. METHODS: Of 2420 acute ischemic stroke patients with large vessel occlusion in a prospective, multicenter, nationwide registry in Japan, patients aged ≥90 years with occlusion of the internal carotid artery or M1 segment of the middle cerebral artery were included. The primary effectiveness outcome was a favorable outcome at 3 months, defined as achieving a modified Rankin Scale score of 0 to 2 or return to at least the prestroke modified Rankin Scale score at 3 months. Safety outcomes included symptomatic intracranial hemorrhage within 72 hours after onset. Intergroup biases were adjusted by multivariable adjustment with inverse probability of treatment weighting. RESULTS: A total of 150 patients (median age, 92 [interquartile range, 90-94] years; median prestroke modified Rankin Scale score, 2 [interquartile range, 0-4]) were analyzed. EVT was performed in 49 patients (32.7%; mechanical thrombectomy, n=43). The EVT group showed shorter time from onset to hospital arrival (P=0.03), higher Alberta Stroke Program Early CT Score (P<0.01), and a higher rate of treatment with intravenous thrombolysis (P<0.01) than the medical management group. The favorable outcome was seen in 28.6% of the EVT group and 6.9% of the medical management group (P<0.01). EVT was associated with the favorable outcome (adjusted odds ratio, 8.44 [95% CI, 1.88-37.97]). Rates of symptomatic intracranial hemorrhage were similar between the EVT group (0.0%) and the medical management group (3.9%; P=0.30). CONCLUSIONS: Patients who underwent EVT showed better functional outcomes than those with medical management without increased symptomatic intracranial hemorrhages. Given proper patient selection, withholding EVT solely on the basis of the age of patients may not offer the best chance of good outcome. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02419794.

Comparisons of Characteristics and Outcomes after Mechanical Thrombectomy for Vertebrobasilar Occlusion with Cardioembolism or Atherosclerotic Brain Infarction: Data from the Tokyo-Tama-Registry of Acute Endovascular Thrombectomy (TREAT).

BACKGROUND: Some reports suggest the efficacy of mechanical thrombectomy (MT) for acute vertebrobasilar artery (VBA) occlusion. The major causes of VBA occlusion include cardioembolism (CE) and large-artery atherosclerosis (LAA). However, the clinical characteristics of each cause remain unclear, and they might be important for decision making related to the indications and strategy of MT. OBJECTIVE: This study aimed to compare functional outcomes and factors affecting outcomes between patients with CE and LAA with acute VBA occlusion. METHODS: This was a retrospective and prospective observational study using data from TREAT (Tokyo-Tama-Registry of Acute Endovascular Thrombectomy), a multicenter registry of MT for acute large-vessel occlusion in the Tokyo metropolitan area. Patients with VBA occlusion classified into CE and LAA groups were analyzed. The primary outcome was a modified Rankin Scale score of 0-2 at 90 days. RESULTS: Seventy-nine patients (57 with CE and 22 with LAA) were eligible from January 2015 to March 2020. Despite significantly shorter puncture-to-recanalization and onset-or-last-well-known-to-recanalization times in the CE group, the primary outcome was not significantly different between the 2 groups (CE, 31.6% vs. LAA, 45.5%; P = 0.248). In the subgroup analysis, patients with CE had worse clinical outcomes in the onset-or-last-well-known-to-door time ≥180 minutes, onset-or-last-well-known-to-door time ≥300 minutes, and low posterior circulation Alberta Stroke Program Early CT Score (≤7) subgroups. CONCLUSIONS: Functional outcomes of VBA occlusion were not significantly different between CE and LAA. Based on the subgroup analysis, patients with CE might have poorer collateral status than do patients with LAA, and earlier recanalization might therefore be desired.

Effect of Mechanical Thrombectomy Without vs With Intravenous Thrombolysis on Functional Outcome Among Patients With Acute Ischemic Stroke: The SKIP Randomized Clinical Trial.

IMPORTANCE: Whether intravenous thrombolysis is needed in combination with mechanical thrombectomy in patients with acute large vessel occlusion stroke is unclear. OBJECTIVE: To examine whether mechanical thrombectomy alone is noninferior to combined intravenous thrombolysis plus mechanical thrombectomy for favorable poststroke outcome. DESIGN, SETTING, AND PARTICIPANTS: Investigator-initiated, multicenter, randomized, open-label, noninferiority clinical trial in 204 patients with acute ischemic stroke due to large vessel occlusion enrolled at 23 hospital networks in Japan from January 1, 2017, to July 31, 2019, with final follow-up on October 31, 2019. INTERVENTIONS: Patients were randomly assigned to mechanical thrombectomy alone (n = 101) or combined intravenous thrombolysis (alteplase at a 0.6-mg/kg dose) plus mechanical thrombectomy (n = 103). MAIN OUTCOMES AND MEASURES: The primary efficacy end point was a favorable outcome defined as a modified Rankin Scale score (range, 0 [no symptoms] to 6 [death]) of 0 to 2 at 90 days, with a noninferiority margin odds ratio of 0.74, assessed using a 1-sided significance threshold of .025 (97.5% CI). There were 7 prespecified secondary efficacy end points, including mortality by day 90. There were 4 prespecified safety end points, including any intracerebral hemorrhage and symptomatic intracerebral hemorrhage within 36 hours. RESULTS: Among 204 patients (median age, 74 years; 62.7% men; median National Institutes of Health Stroke Scale score, 18), all patients completed the trial. Favorable outcome occurred in 60 patients (59.4%) in the mechanical thrombectomy alone group and 59 patients (57.3%) in the combined intravenous thrombolysis plus mechanical thrombectomy group, with no significant between-group difference (difference, 2.1% [1-sided 97.5% CI, -11.4% to ∞]; odds ratio, 1.09 [1-sided 97.5% CI, 0.63 to ∞]; P = .18 for noninferiority). Among the 7 secondary efficacy end points and 4 safety end points, 10 were not significantly different, including mortality at 90 days (8 [7.9%] vs 9 [8.7%]; difference, -0.8% [95% CI, -9.5% to 7.8%]; odds ratio, 0.90 [95% CI, 0.33 to 2.43]; P > .99). Any intracerebral hemorrhage was observed less frequently in the mechanical thrombectomy alone group than in the combined group (34 [33.7%] vs 52 [50.5%]; difference, -16.8% [95% CI, -32.1% to -1.6%]; odds ratio, 0.50 [95% CI, 0.28 to 0.88]; P = .02). Symptomatic intracerebral hemorrhage was not significantly different between groups (6 [5.9%] vs 8 [7.7%]; difference, -1.8% [95% CI, -9.7% to 6.1%]; odds ratio, 0.75 [95% CI, 0.25 to 2.24]; P = .78). CONCLUSIONS AND RELEVANCE: Among patients with acute large vessel occlusion stroke, mechanical thrombectomy alone, compared with combined intravenous thrombolysis plus mechanical thrombectomy, failed to demonstrate noninferiority regarding favorable functional outcome. However, the wide confidence intervals around the effect estimate also did not allow a conclusion of inferiority. TRIAL REGISTRATION: umin.ac.jp/ctr Identifier: UMIN000021488.

Negative impact of Interhospital Transfer on Clinical Outcomes of Mechanical Thrombectomy for Fast Progressive Stroke.

OBJECTIVES: The time-dependence of the clinical outcome of mechanical thrombectomy is higher in the "fast progressor" in whom cerebral ischemia progresses rapidly. The impact of time-consuming interhospital transfer (IT) on the clinical outcome of such patients is unknown. The effect on clinical outcomes of IT of fast progressors was investigated. METHODS: Among the patients enrolled in the Tokyo/Tama REgistry of Acute endovascular Thrombectomy, fast progressor cerebral ischemia cases were retrospectively investigated. In this study, a fast progressor was defined as a case with an Alberta Stroke Program Early CT Score less than 6 and last known well (LKW) to arterial puncture within 6 h. Patients' background characteristics, treatment progress, and the modified Rankin Scale (mRS) score at 3 months were examined. RESULTS: Of a total of 1182 patients, 92 (7.8%) were included, with 76 patients in the direct transfer (DT) group, and 16 patients in the IT group. Median LKW to reperfusion was 190 min and 272 min, respectively (P<.001). The number of patients with mRS scores 0-2 at three months was 22 (28.9%) in the DT group and 1 (6.2%) in the IT group. Interhospital transfer was an independent factor associated with worse outcomes (odds ratio 0.08, 95% confidence interval 0.01-0.87, P=.038). CONCLUSION: This study showed that, among fast progressor patients, the IT group had a worse prognosis than the DT group. To provide good clinical outcomes for fast progressor patients, those who are likely to undergo mechanical thrombectomy should be sent directly to a thrombectomy-capable center.

Long-Term Outcomes of Acute Endovascular Thrombectomy: Tokyo/tama-Registry of Acute Endovascular Thrombectomy (TREAT).

OBJECTIVE: Mechanical thrombectomy (MT) is the recommended treatment for patients with acute ischemic stroke due to large cerebral vessel occlusion (LVO). However, few studies have investigated long-term outcomes after MT. The aim of this study was to investigate functional outcomes at long-term follow-up (1 year after MT) in patients undergoing MT for anterior circulation LVO in real-world clinical practice. METHODS: This was a retrospective and prospective observational study using data from TREAT (Tokyo/tama-Registry of Acute Endovascular Thrombectomy), a multicenter registry of MT for acute LVO in the Tokyo metropolitan area. All subjects emergently transferred and treated with MT from January 2015 to December 2018 were selected. Patients' baseline characteristics and stroke-related parameters were evaluated. The primary outcome was the modified Rankin Scale (mRS) score 1 year after MT. The secondary outcomes were risk factors for long-term good outcomes (mRS score 0-2); transfer system (stroke bypass vs. secondary transfer) was also evaluated as a potential factor associated with good long-term outcomes. RESULTS: A total of 162 cases (mean age 73.0 years, age range 30-97 years; 59.9% male) whose mRS scores at 1 year were obtained were analyzed. The median admission National Institutes of Health Stroke Scale (NIHSS) score was 17. Overall, 42.6% of the patients achieved functional independence at 1-year follow-up. Lower initial NIHSS score and mRS score 0-2 at 90 days were the independent predictors for good long-term outcomes. Stroke bypass was associated with a higher initial NIHSS score and mRS score 0 at 1 year. CONCLUSIONS: A significant number of patients experience a good long-term outcome after MT.

Predictors of intracranial hemorrhage in acute ischemic stroke after endovascular thrombectomy.

BACKGROUND: Limited data are available regarding the predictors, clinical relevance, and bleeding rate by surgical devices of intracranial hemorrhage after endovascular thrombectomy. This is partially explained by the difference in the classification and definition of hemorrhage among studies. The purpose of this study was to identify the predictors of hemorrhagic transformation and isolated subarachnoid hemorrhage after endovascular thrombectomy. METHODS: This was a retrospective, multicenter observational cohort study of consecutive patients who underwent endovascular thrombectomy between January 2015 and December 2018. Univariate and logistic regression analyses were performed to determine the predictors, the impact on clinical outcomes, and the bleeding rate by surgical devices of hemorrhagic transformation and isolated subarachnoid hemorrhage. RESULTS: Among 610 eligible patients, hemorrhagic transformations occurred in 93 (15.2%). Fourteen patients (2.3%) were classified as having symptomatic intracranial hemorrhage. Isolated subarachnoid hemorrhage was found in 60 (9.8%) patients. In the logistic regression analyses, diabetes mellitus (odds ratio: 1.92; 95% confidence interval: 1.06-3.49) was associated with hemorrhagic transformation, and the number of device passes (odds ratio: 1.33; 95% confidence interval: 1.11-1.59) was associated with isolated subarachnoid hemorrhage. Both hemorrhagic transformation and isolated subarachnoid hemorrhage were associated with poor 90-day functional outcomes. There was a significant correlation between treatment with stent retrievers and isolated subarachnoid hemorrhage. CONCLUSIONS: Patients with diabetes mellitus were vulnerable to hemorrhagic transformation, whereas those who underwent several attempts of thrombectomy were susceptible to isolated subarachnoid hemorrhage. Both hemorrhage types worsened the functional outcome. Treatment with the stent retriever was significantly associated with postprocedural isolated subarachnoid hemorrhage.

Tokyo Metropolitan Stroke Emergency Medical Services for Interventional Stroke Treatment: The Tama-REgistry of Acute Thrombectomy (TREAT) Study.

OBJECTIVE: It is not clear how patients with large vessel occlusion (LVO) who have undergone mechanical thrombectomy (MT) were transported to hospitals by emergency medical services. Here, we describe the current status of the stroke delivery system in a large city. METHODS: We investigated data from 328 patients (male, n = 199; average age, 74.8 ± 12.9 years) who underwent MT at 12 facilities in the Tama area of Tokyo, between January 2015 and December 2017. The patients were classified according to the destination institution as Stroke A eligible (group A, n = 266 [8.2%]), Tertiary critical care center (group T; n = 35 [10.7%]), and other destinations such as emergency rooms (group O; n = 27 [8.2%]), and then reasons for using Emergency Medical Service (EMS) services and outcomes were compared among the groups. RESULTS: Rates of milder stroke, and middle cerebral artery occlusion were significantly higher in group A than T, whereas that of vertebral-basilar artery occlusion was significantly lower in group A than in groups T and O. The amount of elapsed time from door to picture (DTP) was significantly lower in group A. The time from onset to recanalization, as well as rates of successful recanalization and favorable outcomes (90-day modified Rankin scale 0-2) did not significantly differ regardless of destination. CONCLUSIONS: Most patients with LVO in the Tama area were categorized into group A. DTP was significantly lower in group A.

Efficacy and Safety of Mechanical Thrombectomy for Occlusion of the Second Segment of the Middle Cerebral Artery : Retrospective Analysis of the Tama-REgistry of Acute endovascular Thrombectomy (TREAT).

BACKGROUND: The efficacy of mechanical thrombectomy in the treatment of occlusions of the second segment of the middle cerebral artery (M2) has not been firmly established. METHODS: This study analyzed data from patients who had undergone mechanical thrombectomy for the first segment of the middle cerebral artery (M1) and M2 occlusion from the Tama-REgistry of Acute endovascular Thrombectomy (TREAT) between January 2015 and March 2017, which is a multicenter database in the Tama area of Tokyo, Japan. The M1 and M2 occlusions were compared in order to evaluate the safety and efficacy of M2 thrombectomy. RESULTS: A total of 515 patients were registered, whereby 160 patients with M1 occlusion and 51 patients with M2 occlusion were included. While the puncture-to-reperfusion time was longer in the M2 occlusions (median 43 min, range 30-61 min vs. median 60 min, range 38-79 min, p = 0.01), no significant differences were seen in the proportion of patients with successful reperfusion, postoperative hemorrhagic complications and good outcome (modified Rankin scale ≤2 at 90 days). Younger age was the only independent factor associated with good outcome in patients with M2 occlusions as determined by the multivariate analysis (p = 0.033, odds ratio 0.91, 95% confidence interval 0.83-0.99). CONCLUSION: The outcome and the safety profile of mechanical thrombectomy for M2 occlusions are favorable and comparable to those of the M1 occlusion thrombectomy.

Thermodynamic analysis of thermal convection based on entropy production.

Flow patterns have a tendency to break the symmetry of an initial state of a system and form another spatiotemporal pattern when the system is driven far from equilibrium by temperature difference. For an annular channel, the axially symmetric flow becomes unstable beyond a given temperature difference threshold imposed in the system, leading to rotational oscillating waves. Many researchers have investigated this transition via linear stability analysis using the fundamental conservation equations and the generic model amplitude equation, i.e., the complex Ginzburg-Landau equation. Here, we present a quantitative study conducted of the thermal convection transition using thermodynamic analysis based on the maximum entropy production principle. Our analysis results reveal that the fluid system under nonequilibrium maximizes the entropy production induced by the thermodynamic flux in a direction perpendicular to the temperature difference. Further, we show that the thermodynamic flux as well as the entropy production can uniquely specify the thermodynamic states of the entire fluid system and propose an entropy production selection rule that can be used to specify the thermodynamic state of a nonequilibrium system.