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.

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.

Optimal endovascular therapy technique for isolated intracranial atherothrombotic stroke-related large vessel occlusion in the acute to subacute stage

BACKGROUND AND PURPOSE

Reocclusion after treatment is a concern in endovascular therapy (EVT) for isolated intracranial atherothrombotic stroke-related large vessel occlusion (AT-LVO). However, the optimal EVT technique for AT-LVO has not yet been investigated. This study evaluated the optimal EVT technique for AT-LVO in a real-world setting.

MATERIALS AND METHODS

We conducted a historical multicenter registry study at 51 centers that enrolled patients with AT-LVO. We divided the patients into three groups based on the EVT technique: mechanical thrombectomy alone (MT-only), percutaneous transluminal angioplasty (PTA), and stent deployment (Stent). MT alone was classified into the MT-only group, PTA and MT-PTA into the PTA group, and MT-Stent, MT-PTA-Stent, PTA-Stent, and Stent-only into the Stent group. The primary outcome was the incidence of reocclusion of the treated vessels within 90 days of EVT completion.

RESULTS

We enrolled 770 patients and analyzed 509 patients. The rates in the MT-only, PTA, and Stent groups were 40.7, 44.4, and 14.9%, respectively. The incidence rate of residual stenosis >70% of final angiography was significantly higher in the MT-only group than in the PTA and Stent groups (MT-only vs. PTA vs. Stent: 34.5% vs. 26.3% vs. 13.2%, p=0.002). The reocclusion rate was significantly lower in the PTA group than in the MT-only group (adjusted hazard ratio [95% confidence interval], 0.48 [0.29-0.80]). Of the patients, 83.5% experienced reocclusion within 10 days after EVT. Alarmingly, a substantial subset (approximately 62.0%) of patients underwent reocclusion within 2 days of EVT. The incidence of modified Rankin scale scores of 0-2 90 days after EVT was not significantly different among the three groups. The incidences of symptomatic intracranial hemorrhage (ICH), any other ICH, and death were not significantly different.

CONCLUSIONS

The incidence rate of reocclusion was significantly lower in the PTA group than in the MT-only group. We found no significant difference in reocclusion rates between the Stent and MT-only groups. In Japan, GP IIb/IIIa inhibitors are not reimbursed. Therefore, PTA might be the preferred choice for AT-LVOs due to the higher reocclusion risk with MT-only. Reocclusion was likely to occur within 10 days, particularly within 2 days post-EVT.

ABBREVIATIONS

EVT = endovascular treatment; LVO = large vessel occlusion; MT = mechanical thrombectomy; PTA = percutaneous transluminal angioplasty; ICH = intracranial hemorrhage; SD = standard deviation; IQR = interquartile range; HRs = hazard ratios; BMI = body mass index; LDL = low-density lipoprotein; HDL = high-density lipoprotein; DAPT = dual antiplatelet therapy; TAPT = triple antiplatelet therapy.

Minimally invasive craniotomy for putaminal hemorrhage using a tubular retractor: A technical note

Background

Minimally invasive endoscopic and stereotactic surgery have been established as surgical treatments for putaminal hemorrhage. However, facilities that do not have equipment for endoscopic or stereotactic surgery will likely have to perform conventional craniotomy. Using a tubular retractor, we were able to perform minimally invasive surgery, such as endoscopic surgery.

Methods

A craniotomy was performed for left putaminal hemorrhage after cerebral infarction treatment. A 3-4 cm craniotomy centered at Kocher's point was performed under general anesthesia. A 2 cm incision was made in the cortex, and a tubular retractor was inserted under a microscope. The hematoma was reached at a position 4-5 cm from the cortex.

Results

Thanks to the tubular retractor, it was relatively easy to observe the hematoma, and it was possible to remove it and confirm hemostasis without difficulty. Brain injury caused by the retractor insertion cavity was small, and no hemostasis was required. The surgery was completed by dura mater closure, bone flap fixation, and wound closure as per the standard. Most of the putaminal hemorrhage could be removed, and there was no rebleeding after the operation. The patient is still undergoing rehabilitation because of aphasia and muscle weakness. Manual Muscle Testing was at three points in the upper limb, and four points in the lower limb remained.

Conclusion

For putaminal hemorrhage, microscopic craniotomy was performed using a tubular retractor and an approach such as endoscopic surgery. Craniotomy, hematoma removal, and hemostasis operations are also considered to be minimally invasive surgeries.

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.

Number of Passes of Endovascular Therapy for Stroke With a Large Ischemic Core: Secondary Analysis of RESCUE-Japan LIMIT

BACKGROUND

The increased risk of intracranial hemorrhage with multiple passes in endovascular therapy (EVT) for large vessel occlusion with a large ischemic core is a concern. We explored the effect of the number of EVT passes on patients in a randomized clinical trial.

METHODS

This post hoc study was the secondary analysis of RESCUE-Japan LIMIT, which was a randomized clinical trial comparing EVT and medical treatment alone for large vessel occlusion with large ischemic core. We grouped patients according to the number of passes with successful reperfusion (modified Thrombolysis in Cerebral Infarction score, ≥2b) in 1, 2, and 3 to 7 passes and failed reperfusion (modified Thrombolysis in Cerebral Infarction score, 0-2a) after any pass in the EVT group, and these groups were compared with medical treatment group. The primary outcome was modified Rankin Scale score of 0 to 3 at 90 days. Secondary outcomes were improvement in National Institutes of Health Stroke Scale score of ≥8 at 48 hours, mortality at 90 days, symptomatic intracranial hemorrhage, and any intracranial hemorrhage within 48 hours.

RESULTS

The number of patients who received EVT with successful reperfusion after 1, 2, and 3 to 7 passes and failed reperfusion were 44, 23, 19, and 14, respectively, and 102 received medical treatment alone. The adjusted odds ratios (95% CIs) for the primary outcome relative to medical treatment were 5.52 (2.23-14.28) after 1 pass, 6.45 (2.22-19.30) after 2 passes, 1.03 (0.15-4.48) after 3 to 7 passes, and 1.17 (0.16-5.37) if reperfusion failed. The adjusted odds ratios (95% CIs) for any intracranial hemorrhage within 48 hours relative to medical treatment were 1.88 (0.90-3.93) after 1 pass, 5.14 (1.97-14.72) after 2 passes, 3.00 (1.09-8.58) after 3 to 7 passes, and 6.16 (1.87-24.27) if reperfusion failed.

CONCLUSIONS

The successful reperfusion within 2 passes was associated with better clinical outcomes.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03702413.

Cavernous sinus dural arteriovenous fistula treated with transvenous embolization through facial vein: A case report

BACKGROUND

Although the inferior petrosal sinus (IPS) is the most common approach route for transvenous embolization (TVE) of cavernous sinus dural arteriovenous fistulas (CSDAVFs), other routes should be chosen in cases which the IPS is occluded. We report a case in which the superior ophthalmic vein (SOV) approach through the facial vein (FV) was the first choice to achieve radical cure of a hemorrhage-onset CSDAVF.

CASE DESCRIPTION

An 81-year-old female presented with a history of transarterial embolization (TAE) and TVE for the left CSDAVF 27 years ago. She was transported to us with a chief complaint of consciousness disturbance, and head computed tomography (CT) showed subcortical hemorrhage in the right frontal lobe. Cerebral angiography revealed CSDAVF with draining into the right SOV and right superficial middle cerebral vein (SMCV). Angiography, computed tomography venography, and contrast-enhanced magnetic resonance imaging did not show IPS, but the outflow pathways to the SOV, FV, and internal jugular vein were confirmed, so an approach through the FV was selected.

CONCLUSION

The FV was selected through the right femoral vein and thanks to the distal access catheter (DAC) being guided to the SOV, the microcatheter could be easily guided to the SMCV through the cavernous sinus (CS). TVE was performed, complete occlusion was confirmed. When preoperative occlusion of the IPS was confirmed, the FV was useful for the first choice of route, and the use of DAC allowed us to complete the treatment accurately and quickly.

Abstract 1: The Very Core Limit Of Endovascular Therapy For Acute Stroke With A Large Ischemic Region

Background and Purpose: To assess the actual malignant core volume in endovascular therapy (EVT) eligible patients with large ischemic regions from the RESCUE-Japan LIMIT database.

Methods: RESCUE-Japan LIMIT was a multicenter, open-label, randomized clinical trial in large vessel occlusion patients with large ischemic region indicated by an ASPECTS valued from 3 to 5. We assessed the volumetrically measured core volume which identifies an unfavorable outcome (modified Rankin Scale; mRS 4-6 at 90 days) by receiver operating characteristic (ROC) analysis in the endovascular therapy (EVT) group. Predictive marginal probabilities were also assessed to identify the unfavorable outcome. Symptomatic intracranial hemorrhages and death within 90 days in the EVT group and the medical management (MM) group were compared. Clinical characteristics and radiological values were also compared.

Results: Of the 203 cases enrolled, 182 patients (92 in EVT group vs. 90 in MM group) had adequate core volume. The mean age was 75.6±10 years old and 46% of females in the EVT group and 77.0±10 years old and 42% of females in the MM group. Median core volume was 94 (IQR; 65.3-147.5) mL in EVT patients and 110 (IQR; 74.0-140.0) mL in those with MM group (P=0.84). ROC analysis identified a core volume of 120 mL as the unfavorable outcome (61/92) in the EVT group (51% sensitivity and 77% specificity, area under curve=0.65) and 99 mL in the MM group (77/91, 62% sensitivity and 54% specificity, area under curve=0.56). Predictive marginal probabilities indicated 132 mL as an overlay of the two groups for achieving the unfavorable functional outcome. Symptomatic intracranial hemorrhage was seen in 9.8% in the EVT group and 5.6% in the MM group (p=0.28), and death within 90 days was 17.4% in the EVT group and 23.3% in the MM group (p=0.32).

Conclusions: The current analysis demonstrates that a core threshold of approximately 130 mL is the upper limit for identifying large ischemic region stroke patients treated with EVT who are unlikely to suffer from unfavorable outcomes. EVT-eligible patients under this threshold may benefit from EVT.

Registration: URL: http://www.clinicaltrials.gov; Unique identifier: NCT03702413.

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.

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.).

Localized kinking during deployment of a flow redirection lumen device (FRED) could be due to excessive pushing

Background:

The safety and efficacy analysis of flow redirection lumen device (FRED) demonstrated the excellent safety profile of FREDs for aneurysm treatment. We describe the first case in which FRED deployment for a paraclinoid aneurysm resulted in in-stent stenosis, necessitating balloon angioplasty, and an additional stent.

Case Description:

A 50-year-old woman had a left paraclinoid aneurysm with a maximum diameter of 6.1 mm. We planned FRED deployment. We experienced in-stent stenosis just after the deployment of a FRED. Devices such as guidewires and catheters could not cross the lesion through the FRED because of an obstruction in the FRED. Balloon angioplasty and subsequent stenting resolved thrombosis and kinking. FRED has potential for kinking locally.

Conclusion:

Surgeons should consider this possibility when treating cerebral aneurysm using FRED. Cone-beam computed tomography after deployment of FRED may be useful for evaluating the stent shape.

Computational Fluid Dynamics Using a Porous Media Setting Predicts Outcome after Flow-Diverter Treatment

BACKGROUND AND PURPOSE

Knowledge about predictors of the outcome of flow-diverter treatment is limited. The aim of this study was to predict the angiographic occlusion status after flow-diverter treatment with computational fluid dynamics using porous media modeling for decision-making in the treatment of large wide-neck aneurysms.

MATERIALS AND METHODS

A total of 27 patients treated with flow-diverter stents were retrospectively analyzed through computational fluid dynamics using pretreatment patient-specific 3D rotational angiography. These patients were classified into no-filling and contrast-filling groups based on the O'Kelly-Marotta scale. The patient characteristics, morphologic variables, and hemodynamic parameters were evaluated for understanding the outcomes of the flow-diverter treatment.

RESULTS

The patient characteristics and morphologic variables were similar between the 2 groups. Flow velocity, wall shear stress, shear rate, modified aneurysmal inflow rate coefficient, and residual flow volume were significantly lower in the no-filling group. A novel parameter, called the normalized residual flow volume, was developed and defined as the residual flow volume normalized by the dome volume. The receiver operating characteristic curve analyses demonstrated that the normalized residual flow volume with an average flow velocity of ≥8.0 cm/s in the aneurysmal dome was the most effective in predicting the flow-diverter treatment outcomes.

CONCLUSIONS

It was established in this study that the hemodynamic parameters could predict the angiographic occlusion status after flow-diverter treatment.

Ischemia-Induced Multipotent Stem Cells Isolated from Stroke Patients Exhibit Higher Neurogenic Differentiation Potential than Bone Marrow-Derived Mesenchymal Stem Cells

Perivascular areas of the brain harbor multipotent stem cells. We recently demonstrated that after a stroke, brain pericytes exhibit features of multipotent stem cells. Moreover, these ischemia-induced multipotent stem cells (iSCs) are present within ischemic areas of the brain of patients diagnosed with stroke. Although increasing evidence shows that iSCs have traits similar to those of mesenchymal stem cells (MSCs), the phenotypic similarities and differences between iSCs and MSCs remain unclear. In this study, we used iSCs extracted from stroke patients (h-iSCs) and compared their neurogenic potential with that of human MSCs (h-MSCs) in vitro. Microarray analysis, fluorescence-activated cell sorting, immunohistochemistry, and multielectrode array were performed to compare the characteristics of h-iSCs and h-MSCs. Although h-iSCs and h-MSCs had similar gene expression profiles, the percentage expressing the neural stem/progenitor cell marker nestin was significantly higher in h-iSCs than in h-MSCs. Consistent with these findings, h-iSCs, but not h-MSCs, differentiated into electrophysiologically functional neurons. In contrast, although both h-iSCs and h-MSCs were able to differentiate into several mesodermal lineages, including adipocytes, osteocytes, and chondrocytes, the potential of h-iSCs to differentiate into adipocytes and osteocytes was relatively low. These results suggest that compared with h-MSCs, h-iSCs predominantly exhibit neural rather than mesenchymal lineages. In addition, these results indicate that h-iSCs have the potential to repair the injured brain of patients with stroke by directly differentiating into neuronal lineages.

Neural regeneration by regionally induced stem cells within post-stroke brains: Novel therapy perspectives for stroke patients

Ischemic stroke is a critical disease which causes serious neurological functional loss such as paresis. Hope for novel therapies is based on the increasing evidence of the presence of stem cell populations in the central nervous system (CNS) and the development of stem-cell-based therapies for stroke patients. Although mesenchymal stem cells (MSCs) represented initially a promising cell source, only a few transplanted MSCs were present near the injured areas of the CNS. Thus, regional stem cells that are present and/or induced in the CNS may be ideal when considering a treatment following ischemic stroke. In this context, we have recently showed that injury/ischemia-induced neural stem/progenitor cells (iNSPCs) and injury/ischemia-induced multipotent stem cells (iSCs) are present within post-stroke human brains and post-stroke mouse brains. This indicates that iNSPCs/iSCs could be developed for clinical applications treating patients with stroke. The present study introduces the traits of mouse and human iNSPCs, with a focus on the future perspective for CNS regenerative therapies using novel iNSPCs/iSCs.

PulseRider-Assisted Coil Embolization for Treatment of Intracranial Bifurcation Aneurysms: A Single-Center Case Series with 24-Month Follow-up

BACKGROUND

Although endovascular coiling of unruptured aneurysms is widely accepted, the endovascular treatment of wide-neck bifurcation aneurysms remains one of the most challenging morphologies. Our purpose was to describe our experience with 24-month follow-up for the treatment of unruptured intracranial bifurcation aneurysms using the PulseRider (Cerenovus, New Brunswick, NJ).

METHODS

This study is a single-center, single-arm registry performed under institutional review board control to evaluate efficacy and safety of the PulseRider. Patients with bifurcation aneurysms were identified and enrolled prospectively. Angiography immediately after treatment and at 6 months, and magnetic resonance imaging and magnetic resonance angiography at 12- and 24-month follow-up were retrospectively analyzed. A modified Rankin score was obtained prior to procedure, at discharge, and at 6-, 12- and 24-month follow-up visits.

RESULTS

Eight patients with a mean age of 66 years were treated with the PulseRider. All patients had bifurcation aneurysms (2 anterior communicating, 2 carotid terminus, and 4 basilar apex). The aneurysm diameters ranged from 4.6 to 13.6 mm (mean 7.4 mm) with dome/neck ratio ranging from 1.4 to 2.2 (mean 1.6). In all cases, the PulseRider was successfully deployed. Complete occlusion was demonstrated at 6-month follow-up on 6 of 8 (75%), near complete occlusion in 1 of 8 (12.5%), and residual aneurysm in 1 of 8 (12.5%) patients. There was no change or recurrence on magnetic resonance angiography, nor clinical complication after the procedure through 24-month follow-up.

CONCLUSIONS

Our experience with 24-month follow-up demonstrated favorable efficacy in the treatment of intracranial wide-neck bifurcation aneurysms using the PulseRider.

Isolation and Characterization of Cerebellum-Derived Stem Cells in Poststroke Human Brain

There is compelling evidence that the mature central nervous system (CNS) harbors stem cell populations outside conventional neurogenic regions. We previously demonstrated that brain pericytes (PCs) in both mouse and human exhibit multipotency to differentiate into various neural lineages following cerebral ischemia. PCs are found throughout the CNS, including cerebellum, but it remains unclear whether cerebellar PCs also form ischemia-induced multipotent stem cells (iSCs). In this study, we demonstrate that putative iSCs can be isolated from poststroke human cerebellum (cerebellar iSCs [cl-iSCs]). These cl-iSCs exhibited multipotency and differentiated into electrophysiologically active neurons. Neurogenic potential was also confirmed in single-cell suspensions. DNA microarray analysis revealed highly similar gene expression patterns between PCs and cl-iSCs, suggesting PC origin. Global gene expression comparison with cerebral iSCs revealed general similarity, but cl-iSCs differentially expressed certain cerebellum-specific genes. Thus, putative iSCs are present in poststroke cerebellum and possess region-specific traits, suggesting potential capacity to regenerate functional cerebellar neurons following ischemic stroke.

Abstract TP143: Potential of Cerebellum-derived Stem Cells in Human Brain to Regenerate Functional Neurons Following Ischemic Stroke

Introduction: Despite the availability of effective reperfusion therapies, only a few prove beneficial to the patients after stroke, owing to their limited time window. We had earlier demonstrated that adult brain pericytes develop stemness following ischemia, and these ischemia-induced multipotent stem cells (iSCs) can self-propagate and differentiate into mature neural cells, including neurons (Nakagomi et al. Eur J Neurosci. 2009, Stem Cells. 2009, 2015). More recently, we have shown putative iSCs to be present within post-stroke human cerebral tissues (Tatebayashi K et al. Stem Cells Dev 2017). The current study aimed to establish iSCs from cerebellar infarction of two patients and examine their characteristics.

Methods: We isolated iSCs from post-stroke human cerebellum, examined their characteristics by Polymerase chain reaction and immunocytochemistry, and compared their traits with those of others by microarray and flow cytometry analyses. Furthermore, we investigated the cerebellar-iSCs (cl-iSCs) for multi-potency and differentiation into functional neurons. Electrophysiological properties were analyzed using multi-electrode arrays.

Results: The isolated cl-iSCs exhibited multi-potency and differentiated into electrophysiologically active neurons (Fig. A). Neurogenic potential was confirmed in single-cell suspensions (Fig. B.C). Highly similar gene expression patterns were observed between pericytes and iSCs (Fig. D), and a strong lineage resemblance between cl-iSCs and cerebral ischemia-induced multi-potent stem cells (cr-iSCs) was revealed, although cl-iSCs differentially expressed certain cerebellum-specific genes.

Conclusions: Putative iSCs are present in post-stroke cerebellum and possess region-specific traits, suggesting their potential to regenerate functional neurons following an ischemic stroke.

Intravenous administration of human adipose-derived stem cells ameliorates motor and cognitive function for intracerebral hemorrhage mouse model

Even today, intracerebral hemorrhage (ICH) is a major cause of death and disabilities. Rehabilitation is preferentially applied for functional recovery although its effect is limited. Recent studies have suggested that intravenous administration of mesenchymal stem cells would improve the post-ICH neurological deficits. Human adipose-derived stem cells (hADSCs) have been established in our laboratory. We aimed to evaluate the therapeutic efficacy of the hADSCs on the post-ICH neurological deficits using a clinical-relevant ICH mouse model. We also evaluated immune responses to clarify the underlying mechanisms. The hADSCs expressed MSC markers at high levels. The hADSCs administration into the ICH-bearing mice improved the neurological deficits during the subacute phases, which was shown by neurobehavioral experiments. Besides, the hADSC administration decreased the number of CD11⁺CD45⁺ cells and increased the proportion of CD86⁺ and Ly6C⁺ cells in the ICH lesions. In summary, intravenous administration of hADSCs during the acute phase improved ICH-induced neurological deficits during the subacute phase because of the suppression of acute inflammation mediated by CD11⁺CD45⁺ subpopulations. Our data suggest that hADSCs can be served as a novel strategy for ICH treatment.

Comparative Characterization of Ischemia-Induced Brain Multipotent Stem Cells with Mesenchymal Stem Cells: Similarities and Differences

Mesenchymal stem cells (MSCs) are multipotent stem cells localized to the perivascular regions of various organs, including bone marrow (BM). While MSC transplantation represents a promising stem cell-based therapy for ischemic stroke, increasing evidence indicates that exogenously administered MSCs rarely accumulate in the injured central nervous system (CNS). Therefore, compared with MSCs, regionally derived brain multipotent stem cells may be a superior source to elicit regeneration of the CNS following ischemic injury. We previously identified ischemia-induced multipotent stem cells (iSCs) as likely originating from brain pericytes/perivascular cells (PCs) within poststroke regions. However, detailed characteristics of iSCs and their comparison with MSCs remains to be investigated. In the present study, we compared iSCs with BM-derived MSCs, with a focus on the stemness and neuron-generating activity of each cell type. From our results, stem and undifferentiated cell markers, including c-myc and Klf4, were found to be expressed in iSCs and BM-MSCs. In addition, both cell types exhibited the ability to differentiate into mesoderm lineages, including as osteoblasts, adipocytes, and chondrocytes. However, compared with BM-MSCs, high expression of neural stem cell markers, including nestin and Sox2, were found in iSCs. In addition, iSCs, but not BM-MSCs, formed neurosphere-like cell clusters that differentiated into functional neurons. These results demonstrate that iSCs are likely multipotent stem cells with the ability to differentiate into not only mesoderm, but also neural, lineages. Collectively, our novel findings suggest that locally induced iSCs may contribute to CNS repair by producing neuronal cells following ischemic stroke.

Quantitative Analysis of Conebeam CT for Delineating Stents in Stent-Assisted Coil Embolization

BACKGROUND AND PURPOSE

Innovative techniques and device-related advances have improved the outcomes of neuroendovascular treatment. 3D imaging has previously used 2 × 2 binning, but 1 × 1 binning has recently been made available. The aim of this study was to evaluate the quantitative ability of conebeam CT for stent delineation and to investigate its effectiveness in the clinical environment.

MATERIALS AND METHODS

Four acquisition groups of 3D MIP images acquired using conebeam CT with varying conditions (acquisition time, 10 or 20 seconds and binning, 1 × 1 or 2 × 2) were compared. Two methods of analysis were performed, a phantom study and an analysis of 28 randomly selected patients. The phantom study assessed the contrast-to-noise ratio and full width at half maximum values in conebeam CT images of intracranial stent struts. In the clinical subjects, we assessed contrast-to-noise ratio, full width at half maximum, and dose-area product.

RESULTS

In the phantom study, the contrast-to-noise ratio was not considerably different between 10- and 20-second acquisition times at equivalent binning settings. Additionally, the contrast-to-noise ratio at equivalent acquisition times did not differ considerably by binning setting. For the full width at half maximum results, equivalent acquisition times differed significantly by binning setting. In the clinical analyses, the 10-second/1 × 1 group (versus 20 second/2 × 2) showed a higher contrast-to-noise ratio (P < .05) and a dose-area product reduced by approximately 70% (P < .05), but the difference in full width at half maximum was not significant (P = .20).

CONCLUSIONS

For stent-assisted coil embolization, quantitative assessment of conebeam CT showed that 10 second/1 × 1 was equivalent to 20 second/2 × 2 for imaging deployed intracranial stents. Furthermore, the 10-second/1 × 1 settings resulted in a much smaller DAP.

Optimal dilution of contrast medium for quantitating parenchymal blood volume using a flat-panel detector

Objective Similar to perfusion studies after acute ischemic stroke, measuring cerebral blood volume (CBV) via C-arm computed tomography before and after therapeutic interventions may help gauge subsequent revascularization. We tested serial dilutions of intra-arterial injectable contrast medium (CM) to determine the optimal CM concentration for quantifying parenchymal blood volume by flat-panel detector imaging (FD-PBV). Methods CM was diluted via saline power injector, instituting time delays for FD-PBV studies. A red/green/blue (RGB) color scale was employed to quantify/compare FD-PBV and magnetic resonance-derived CBV (MRCBV). Results Contrast values of right and left common carotid arteries did not differ significantly at CM dilutions of ≥20%. RGB analysis of FD-PBV imaging (relative to MR-CVB), showed CM dilution altered the colors (by 16%), increasing red and decreasing blue ratios. Conclusion Diluting CM to 20% resulted in no laterality differential of FD-PBV imaging, with left/right quantitative ratios approaching 1.1 (optimal for clinical use).