Successful shrinkage of a recurrent partially thrombosed symptomatic large basilar tip aneurysm using a Target 3D Coil

Background

Standalone coil embolization is often less effective for partially thrombosed intracerebral aneurysms (PTIA) because of the risk of frequent recurrence if the coil migrates into the thrombus. This report describes a case of PTIA at the basilar tip in which simple coil embolization using a Target 3D Coil resulted in sustained remission without recurrence during long-term follow-up.

Case Description

The patient was a 63-year-old male who presented with right oculomotor nerve palsy after having undergone direct surgery for a basilar artery aneurysm 15 years earlier. Recurrence with partial thrombosis of the basilar artery aneurysm was diagnosed. Target 3D Coil embolization with frame construction in the aneurysmal sac was performed, resulting in the complete disappearance of the aneurysm and improvement of the oculomotor nerve palsy. Magnetic resonance imaging at five years postoperatively confirmed that the thrombus had completely disappeared, and there was no recurrence of the aneurysm. The closed loops in the Target 3D Coil may have contributed to the cohesive mass of coils remaining in the sac of the PTIA, potentially leading to healing.

Conclusion

The characteristics of the Target 3D Coil may have prevented migration of the coil into the thrombus, potentially contributing to the successful resolution of the aneurysm.

Incidence and Outcomes of Aneurysmal Subarachnoid Hemorrhage: A Multicenter Retrospective Registry-based Descriptive Trial in Kobe City

The current study aims to evaluate the incidence and results of aneurysmal subarachnoid hemorrhage (aSAH) throughout Kobe City. Based on a multicenter retrospective registry-based descriptive trial involving all 13 primary stroke centers in Kobe City, patients with aSAH treated between October 2017 and September 2019 were studied. A total of 334 patients were included, with an estimated age-adjusted incidence of 11.12 per 100,000 person-years. Curative treatment was given to 94% of patients, with endovascular treatment (51%) preferred over surgical treatment (43%). Of the patients, 12% were treated by shunt surgery for sequential hydrocephalus with a worse outcome at 30 days or discharge (14% vs. 46%, odds ratio (OR): 0.19, 95% confidence interval (CI): 0.088-0.39, p-value <0.001). As for vasospasm and delayed cerebral ischemia, most patients were given intravenous fasudil infusion (73%), with endovascular treatment for vasospasm in 24 cases (7.2%). The fasudil group had more good outcomes (42% vs. 30%, OR: 1.64, 95% CI: 0.95-2.87, p-value = 0.075) and significantly less death (3.3% vs. 35%, OR: 0.064, 95% CI: 0.024-0.15, p-value <0.001) at 30 days or discharge. Mortality rose from 12% at 30 days or discharge to 17% at 1 year, but neurological function distribution improved over time (modified Rankin Scale 0-2 was 39% at 30 days or discharge, 53% at 60 days, and 63% at 1 year). Our retrospective registered trial presented various statistics on aSAH, summarizing the current treatment status and prognosis.

Effects of carotid revascularization on cognitive function and brain functional connectivity in carotid stenosis patients with cognitive impairment: a pilot study

OBJECTIVE

Carotid stenosis can lead to both cognitive impairment (CI) and ischemic stroke. Although carotid revascularization surgery, which includes carotid endarterectomy (CEA) and carotid artery stenting (CAS), can prevent future strokes, its effect on cognitive function is controversial. In this study, the authors examined resting-state functional connectivity (FC) in carotid stenosis patients with CI undergoing revascularization surgery, with a particular focus on the default mode network (DMN).

METHODS

Twenty-seven patients with carotid stenosis who were scheduled to undergo CEA or CAS between April 2016 and December 2020 were prospectively enrolled. A cognitive assessment, including the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB), and Japanese version of the Montreal Cognitive Assessment (MoCA), as well as resting-state functional MRI, was performed 1 week preoperatively and 3 months postoperatively. For FC analysis, a seed was placed in the region associated with the DMN. The patients were divided into two groups according to the preoperative MoCA score: a normal cognition (NC) group (MoCA score ≥ 26) and a CI group (MoCA score < 26). The difference in cognitive function and FC between the NC and CI groups was investigated first, and then the change in cognitive function and FC after carotid revascularization was investigated in the CI group.

RESULTS

There were 11 and 16 patients in the NC and CI groups, respectively. The FC of the medial prefrontal cortex with the precuneus and that of the left lateral parietal cortex (LLP) with the right cerebellum were significantly lower in the CI group than in the NC group. In the CI group, significant improvements were found in MMSE (25.3 vs 26.8, p = 0.02), FAB (14.4 vs 15.6, p = 0.01), and MoCA scores (20.1 vs 23.9, p = 0.0001) after revascularization surgery. Significantly increased FC of the LLP with the right intracalcarine cortex, right lingual gyrus, and precuneus was observed after carotid revascularization. In addition, there was a significant positive correlation between the increased FC of the LLP with the precuneus and improvement in the MoCA score after carotid revascularization.

CONCLUSIONS

These findings suggest that carotid revascularization, including CEA and CAS, might improve cognitive function based on brain FC in the DMN in carotid stenosis patients with CI.

Von Hippel-Lindau disease with intracranial hemorrhage due to arteriovenous anastomosis via multiple spinal hemangioblastomas: illustrative case

BACKGROUND

Some spinal hemangioblastomas (HBLs) resemble spinal vascular malformations. Intracranial subarachnoid hemorrhage (SAH) secondary to spinal HBL has rarely been reported.

OBSERVATIONS

A 67-year-old man with a prolonged von Hippel-Lindau disease (VHL) history presented with sudden headache and vomiting. Cranial and cervical computed tomography (CT) revealed severe infratentorial, supratentorial, and cervical SAH. Cranial CT angiography and magnetic resonance imaging revealed a mismatch in hemorrhage and intracranial tumor localization, with no vascular lesions that could lead to intracranial SAH. Cervical CT angiography revealed abnormal blood vessels originating from 5 spinal tumors suspected to be HBLs. We considered that the SAH was caused by venous reflex from vascular malformation-like spinal HBLs. Transarterial embolization (TAE) of the feeding artery of HBLs was performed to improve symptoms and reduce rebleeding risk. Nine months after TAE, angiography showed no venous reflux into the intracranial space. Ten months later, the authors excised the T1-2 tumor because the patient complained of progressive paralysis of the right upper extremity.

LESSONS

In HBL with prolonged VHL, intracranial hemorrhage due to venous regurgitation via a mimicked vascular malformation may occur. Reducing venous reflux with TAE may improve symptoms and prevent rebleeding.

Pseudo-continuous arterial spin labeling with short post-labeling delay time sensitively reflects the hemodynamics of symptomatic patients with permanent large vessel occlusion before and after revascularization

BACKGROUND AND PURPOSE

This study evaluated the feasibility of arterial spin labeling (ASL) for diagnosing hemodynamic stroke due to permanent anterior circulation large vessel occlusion.

METHODS

Three-dimensional pseudo-continuous ASL data at two post-labeling delay (PLD) times (1.5 and 2.5 s) in patients with unilateral permanent middle cerebral artery (MCA) segment 1 (M1) or internal cerebral artery (ICA) occlusion were acquired during routine magnetic resonance angiography. Sixty-one patients with symptomatic occlusion (M1, 24; ICA, 37) and 69 patients with asymptomatic occlusion (M1, 21; ICA, 48) were enrolled. Regions of interest were automatically placed in the MCA region using a template. The respective scans were compared with asymptomatic M1 or ICA occlusion scans. The ratio of signal intensity (occlusion side/non-occlusion side) in the perfusion area of MCA (asymmetry index [AI]) was compared between both groups.

RESULTS

In both PLD groups, AI was significantly lower in symptomatic patients than in asymptomatic patients. The receiver operating characteristic curve showed moderate capacity for the prediction of symptomatic AI in both groups (area under the curve, 0.739 and 0.712, respectively). As a result of extracranial-intracranial bypass operation in 28 symptomatic (M1, eight; ICA, 20) patients, AI was significantly higher postoperatively in the PLD 1.5 s group than in the PLD 2.5 s group.

CONCLUSION

In symptomatic patients with permanent large vessel occlusion, the signal intensity ratio of pseudo-continuous ASL with short PLD sensitively reflects the hemodynamics before and after revascularization; therefore, this technique may be an alternative method in situations where PET or SPECT cannot be performed.

Absence of the Anterior Communicating Artery on Selective MRA is Associated with New Ischemic Lesions on MRI after Carotid Revascularization

BACKGROUND AND PURPOSE

ICA-selective MRA using a pencil beam presaturation pulse can accurately visualize anterior communicating artery flow. We evaluated the impact of anterior communicating artery flow on the perioperative hemodynamic status and new ischemic lesions after carotid revascularization.

MATERIALS AND METHODS

Eighty-three patients with carotid artery stenosis were included. We assessed anterior communicating artery flow using ICA-selective MRA. The preoperative hemodynamic status was measured using SPECT. We also measured the change in regional cerebral oxygen saturation after temporary ICA occlusion. New ischemic lesions were evaluated by DWI on the day after treatment.

RESULTS

Anterior communicating artery flow was detected in 61 patients, but it was not detected in 22 patients. Preoperative cerebrovascular reactivity was significantly higher in patients with (versus without) anterior communicating artery flow with a mean peak systolic velocity of ≥200 cm/s (39.6% [SD, 23.8%] versus 25.2% [SD, 16.4%]; P = .030). The decrease in mean regional cerebral oxygen saturation was significantly greater in patients without (versus with) anterior communicating artery flow (8.5% [SD, 5.6%] versus 3.7% [SD, 3.8%]; P = .002). New ischemic lesions after the procedure were observed in 23 patients. The multivariate logistic regression analysis revealed that anterior communicating artery flow (OR, 0.07; 95% CI, 0.012-0.45; P = .005) was associated with new ischemic lesions.

CONCLUSIONS

The absence of anterior communicating artery flow influenced the perioperative hemodynamic status in patients with carotid stenosis and was associated with an increased incidence of new ischemic lesions after carotid revascularization.

Successful Thrombectomy for Endocarditis-Related Stroke in a Very Young Patient: Illustrative Case

Objective

Unlike in older adults, ischemic stroke in young patients occurs secondary to preexisting conditions. Infective endocarditis (IE) is among the most important causes of stroke in young adults and has a severe prognosis. There are few reports of mechanical thrombectomy (MT) for IE-induced large-vessel occlusion (LVO). This paper reports a case of acute IE-induced LVO in a young patient who was successfully treated with MT.

Case Presentation

An 18-year-old woman presented to our hospital with severe headache, high fever, and left fingertip pain. She was admitted to the Department of Neurology for conservative treatment of suspected meningitis. On day 2 of admission, she developed acute left hemiparesis, left hemispatial neglect, and dysarthria. MRA showed occlusion of the right M1 segment of the middle cerebral artery, and the patient immediately underwent MT. After a single pass, we achieved thrombolysis in cerebral infarction 2b. A white clot was diagnosed as a vegetation on pathological examination. As transesophageal echocardiography showed a vegetation on the mitral valve, the patient was diagnosed with IE and underwent cardiovascular surgery. The patient recovered well and underwent additional treatment and rehabilitation.

Conclusion

Although rare, IE-induced septic emboli may occur in young patients with LVO, necessitating MT and pathological diagnosis of the clot.

Contribution of Endoplasmic Reticulum Stress to the Clinical Instability of Carotid Plaques in Human Carotid Stenosis

Endoplasmic reticulum (ER) stress is an important process during the progression of atherosclerosis. The aim of this study was to elucidate the association of ER stress and clinical instability of carotid plaque. One hundred ninety-three patients with carotid stenosis undergoing carotid endarterectomies (CEAs) were enrolled. We classified the patients into 3 groups: the asymptomatic, symptomatic, and cTIA (crescendo transient ischemic attack)/SIE (stroke in evolution) groups. Immunohistological staining was performed to assess ER stress and apoptosis. The correlation between ER stress marker expression and clinical instability was analyzed by Tukey-Kramer test and ordinal logistic regression. From the 193 CEAs, 24 asymptomatic plaques and 24 symptomatic plaques were randomly selected, and all 7 plaques in the cTIA/SIE group were selected. Glycophorin A staining demonstrated significant correlation between intraplaque hemorrhage and clinical instability (odds ratio [OR], 1.27; 95%CI, 1.14-1.41). The expression of ER stress markers (glucose-regulated protein 78 [GRP78] and C/EBP homologous protein [CHOP]) exhibited a significant correlation with clinical instability (GRP78: OR, 1.25; 95%CI, 1.14-1.38, CHOP: OR, 1.39; 95%CI, 1.16-1.66). Double-label immunofluorescence demonstrated ER stress markers were detected in CD68-positive cells and smooth muscle actin (SMA)-positive cells. The coexpression of the ER stress markers exhibited a significant correlation with clinical instability (CD68/GRP78: OR, 1.13; 95%CI, 1.05-1.20, CD68/CHOP: OR, 1.092; 95%CI, 1.04-1.14, SMA/CHOP: OR, 1.082; 95%CI, 1.04-1.13). However, the colocalization of CHOP and cleaved caspase-3 (apoptosis marker) did not correlate with clinical instability. These findings indicated that the ER stress pathway may be a potential therapeutic target in the prevention of stroke.

Successful multiple burr hole openings for limb-shaking transient ischemic attack due to moyamoya disease: illustrative case

BACKGROUND

Limb-shaking transient ischemic attacks (LS-TIAs) are a rare form of TIAs that present as involuntary movements of the limbs and indicate severe cerebral hypoperfusion. LS-TIAs are often reported in patients with carotid artery stenosis but can also affect patients with intracranial artery stenosis and moyamoya disease (MMD).

OBSERVATIONS

A 72-year-old woman presented with repeated episodes of involuntary shaking movements of the right upper limb. Cerebral angiography revealed complete occlusion of the M1 segment of the left middle cerebral artery (MCA), and the left hemisphere was supplied by moyamoya vessels. She was treated with left direct revascularization without complications, and her involuntary movements subsided. However, she demonstrated involuntary shaking movements of the right lower limb 2 months postoperatively. Cerebral angiography revealed complete occlusion of the A1 segment of the left anterior cerebral artery (ACA). The multiple burr hole opening (MBHO) procedure was performed to improve perfusion in the left ACA territory and after 3 months, the patient’s symptoms resolved.

LESSONS

This case demonstrated that LS-TIAs can also develop as ischemic symptoms due to MMD. Moreover, instances of LS-TIA of the upper and lower limbs developed separately in the same patient. The patient’s symptoms improved with direct revascularization and MBHO.

Potential of machine learning to predict early ischemic events after carotid endarterectomy or stenting: a comparison with surgeon predictions

Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are recommended for high stroke-risk patients with carotid artery stenosis to reduce ischemic events. However, we often face difficulty in determining the best treatment strategy. We aimed to develop an accurate post-CEA/CAS outcome prediction model using machine learning that will serve as a basis for a new decision support tool for patient-specific treatment planning. Retrospectively collected data from 165 consecutive patients with carotid stenosis underwent CEA or CAS and were divided into training and test samples. The following five machine learning algorithms were tuned, and their predictive performance was evaluated by comparison with surgeon predictions: an artificial neural network, logistic regression, support vector machine, random forest, and extreme gradient boosting (XGBoost). Seventeen clinical factors were introduced into the models. Outcome was defined as any ischemic stroke within 30 days after treatment including asymptomatic diffusion-weighted imaging abnormalities. The XGBoost model performed the best in the evaluation; its sensitivity, specificity, positive predictive value, and accuracy were 31.9%, 94.6%, 47.2%, and 86.2%, respectively. These statistical measures were comparable to those of surgeons. Internal carotid artery peak systolic velocity, low-density lipoprotein cholesterol, and procedure (CEA or CAS) were the most contributing factors according to the XGBoost algorithm. We were able to develop a post-procedural outcome prediction model comparable to surgeons in performance. The accurate outcome prediction model will make it possible to make a more appropriate patient-specific selection of CEA or CAS for the treatment of carotid artery stenosis.

Geranylgeranylacetone attenuates cerebral ischemia-reperfusion injury in rats through the augmentation of HSP 27 phosphorylation: a preliminary study

Background

We previously reported that heat shock protein 27 (HSP27) phosphorylation plays an important role in the activation of glucose-6-phosphate dehydrogenase (G6PD), resulting in the upregulation of the pentose phosphate pathway and antioxidant effects against cerebral ischemia–reperfusion injury. The present study investigated the effect of geranylgeranylacetone, an inducer of HSP27, on ischemia–reperfusion injury in male rats as a preliminary study to see if further research of the effects of geranylgeranylacetone on the ischemic stroke was warranted.

Methods

In all experiments, male Wistar rats were used. First, we conducted pathway activity profiling based on a gas chromatography–mass spectrometry to identify ischemia–reperfusion-related metabolic pathways. Next, we investigated the effects of geranylgeranylacetone on the pentose phosphate pathway and ischemia–reperfusion injury by real-time polymerase chain reaction (RT-PCR), immunoblotting, and G6PD activity, protein carbonylation and infarct volume analysis. Geranylgeranylacetone or vehicle was injected intracerebroventricularly 3 h prior to middle cerebral artery occlusion or sham operation.

Results

Pathway activity profiling demonstrated that changes in the metabolic state depended on reperfusion time and that the pentose phosphate pathway and taurine-hypotaurine metabolism pathway were the most strongly related to reperfusion among 137 metabolic pathways. RT-PCR demonstrated that geranylgeranylacetone did not significantly affect the increase in HSP27 transcript levels after ischemia–reperfusion. Immunoblotting showed that geranylgeranylacetone did not significantly affect the elevation of HSP27 protein levels. However, geranylgeranylacetone significantly increase the elevation of phosphorylation of HSP27 after ischemia–reperfusion. In addition, geranylgeranylacetone significantly affected the increase in G6PD activity, and reduced the increase in protein carbonylation after ischemia–reperfusion. Accordingly, geranylgeranylacetone significantly reduced the infarct size (median 31.3% vs 19.9%, p = 0.0013).

Conclusions

As a preliminary study, these findings suggest that geranylgeranylacetone may be a promising agent for the treatment of ischemic stroke and would be worthy of further study. Further studies are required to clearly delineate the mechanism of geranylgeranylacetone-induced HSP27 phosphorylation in antioxidant effects, which may guide the development of new approaches for minimizing the impact of cerebral ischemia–reperfusion injury.

Glioma cells require one-carbon metabolism to survive glutamine starvation

Cancer cells optimize nutrient utilization to supply energetic and biosynthetic pathways. This metabolic process also includes redox maintenance and epigenetic regulation through nucleic acid and protein methylation, which enhance tumorigenicity and clinical resistance. However, less is known about how cancer cells exhibit metabolic flexibility to sustain cell growth and survival from nutrient starvation. Here, we find that serine and glycine levels were higher in low-nutrient regions of tumors in glioblastoma multiforme (GBM) patients than they were in other regions. Metabolic and functional studies in GBM cells demonstrated that serine availability and one-carbon metabolism support glioma cell survival following glutamine deprivation. Serine synthesis was mediated through autophagy rather than glycolysis. Gene expression analysis identified upregulation of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) to regulate one-carbon metabolism. In clinical samples, MTHFD2 expression was highest in the nutrient-poor areas around “pseudopalisading necrosis.” Genetic suppression of MTHFD2 and autophagy inhibition caused tumor cell death and growth inhibition of glioma cells upon glutamine deprivation. These results highlight a critical role for serine-dependent one-carbon metabolism in surviving glutamine starvation and suggest new therapeutic targets for glioma cells adapting to a low-nutrient microenvironment.

MET-08 Air in cistern or ventricle after brain metastasis surgery is a predictor of early postoperative intracranial recurrence

INTRODUCTION: The operations of brain metastasis are on the increase as a result of more routine diagnostic imaging and improved extracranial systemic treatment strategies. Opening of the cistern or ventricle during tumor resection may promote local recurrence and cerebrospinal fluid dissemination. We investigated whether the air found in the cistern/ventricle on postoperative Computed tomography (CT) was a predictor of postoperative recurrence.

METHODS: Between 2012 and 2019, 27 patients with single brain metastasis were treated with gross total resection at our hospital. The patients in which air was found in the cistern or ventricle of the head CT on the day after surgery was designated as air(+) group, and the patients without air was designated as air(-) group. The primary outcome was the local recurrence, as diagnosed with neuroimaging. The death due to other than brain metastasis was defined as competing risk.

RESULTS: CT air(+) group was 17 patients, whereas CT air(-) group was 10 patients. There was no significant difference between the two groups, such as age and sex. Estimated 1-year brain tumor recurrence rate was 70% in the air(+) group and 5.9% in the air(-) group. (p = 0.004). On the other hand, no significant difference was observed in estimated 1-year competing risk between in the air(+) group (10%) and in the air(-) group (2.4%).

CONCLUSION: En bloc resection of brain metastasis is effective, but there was no report on the risk of opening the cistern or ventricle. Our results indicate that postoperative air presence in the cistern or ventricle could be a predictor of early postoperative recurrence. In metastatic brain tumor removal, the cistern and ventricle should not be opened, and close follow-up should be done if air in the cistern or ventricle is detected on postoperative CT.

Impact of introducing endovascular treatment on acute ischemic stroke outcomes: A shift from an era of medical management to thrombectomy in Japan

Background

Endovascular treatment (EVT) has increasingly become the standard treatment of acute cerebral large vessel occlusion (LVO). We evaluated the impact of introducing EVT on LVO therapy in a single center where intravenous thrombolysis (IVT) had been the only recanalization therapy.

Materials and methods

Between April 2013 and March 2017, 354 consecutive patients with LVO admitted to our institution were analyzed. We compared outcomes between two chronological groups before (Pre-EVT group) and after (Post-EVT group) introducing EVT in April 2015. We assessed prognostic factors for favorable outcomes (modified Rankin scale score ≤2 at 90 days).

Results

In the Pre-EVT group, all 140 patients were treated medically, including 30 patients (21%) undergoing IVT. In the Post-EVT group, 118 patients (55%) underwent EVT, and the remaining 96 patients treated medically, including six patients (3%) undergoing IVT. The proportion undergoing recanalization therapy with IVT or EVT significantly increased after introducing EVT (21% versus 58%, p < 0.001). The rate of patients achieving favorable outcomes also significantly increased (14% versus 31%, p < 0.001). In multivariate regression analysis, introducing EVT was an independent predictive factor after adjusting for age, stroke severity and extent, and time (p = 0.005). The arrival time in patients with helicopter transport was significantly shorter than that with ground ambulance for a distance of more than 10 km (p < 0.001).

Conclusions

This study demonstrated that the introduction of EVT improved outcomes of acute LVO patients, increasing the opportunity to receive recanalization therapy. Further efforts to establish medical systems to provide EVT are required throughout the country.

Outcome and effect of endovascular treatment in stroke associated with acute extracranial internal carotid artery occlusion: Single-center experience in Japan

BACKGROUND

Positive data from several randomized controlled trials (RCTs) of endovascular treatment (EVT) for acute ischemic stroke (AIS) patients with anterior circulation large vessel occlusion (ACLVO) have emerged. However, little evidence exists on EVT for acute extracranial internal carotid artery (EC-ICA) occlusion. We therefore analysed the outcome and effect of EVT on AIS due to ACLVO caused by EC-ICA occlusion, including tandem occlusion compared with that caused by pure intracranial artery occlusion.

METHODS

A total of 135 consecutive AIS patients with ACLVO between July 2014 and December 2017 were identified. We retrospectively analysed the efficacy of EVT for ACLVO after introducing a stent retriever (SR). We classified ACLVO into the following categories: group A, intracranial artery occlusion without EC-ICA occlusion (pure intracranial artery occlusion), and group B, ipsilateral EC-ICA occlusion with/without intracranial artery occlusion.

RESULTS

In total, 65 patients were enrolled. Group A comprised 71% (46/65) of all cases. No difference was observed in terms of age, National Institute of Health Stroke Scale (NIHSS) score, Alberta Stroke Program Early Computed Tomography Score-Diffusion Weighted imaging (ASPECTS-DWI), several clinical time intervals, rate of successful revascularization (74% versus 84%), and rate of functional independence (42% versus 39%) between groups A and B. In all patients, an ASPECTS-DWI ≥6 and an onset-to-door time ≤6 h were associated with good outcome, whereas intracranial artery occlusion without EC-ICA occlusion (pure intracranial artery occlusion) was not.

CONCLUSIONS

The outcomes support the efficacy of EVT in stroke associated with acute EC-ICA occlusion. In the EVT of AIS due to ACLVO, there was no significant difference in the results between ipsilateral EC-ICA occlusion with/without intracranial artery occlusion and intracranial artery occlusion without EC-ICA occlusion (pure intracranial artery occlusion).

Abstract WP474: Improvement of Cognitive Function and Reorganization of Brain Networks Following Carotid Endarterectomy and Carotid Artery Stenting

Background: Internal carotid artery stenosis (ICS) can lead to cognitive impairment as well as ischemic stroke. Although carotid revascularization surgery, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS), can prevent future strokes, the effect of revascularization on cognitive function is controversial. In this study, we examined the resting-state functional connectivity (FC) in ICS patients undergoing revascularization surgery, with a special focus on the Default Mode Network (DMN).

Methods: We prospectively enrolled 24 ICS patients, who were expecting the intervention of CEA (14 cases) or CAS (10 cases). Cognitive assessment, including the Mini-Mental State Examination (MMSE), the Frontal Assessement Battery (FAB), and the Japanese version of the Montreal Cognitive Assessment (MoCA-J) and rs-fMRI were administered ≤ 1 week preoperatively and postoperatively at 1 week. For the analysis of FC, a seed was placed in the region associated with DMN.

Results: After revascularization surgery, significant improvement in the score of MMSE (27.4 vs 28.4, P = 0.03) and MoCA-J (23.1 vs 25.0, P = 0.0001) was found. As for the analysis of the CAS and CEA groups, the MoCA-J score of the CEA group (24.1 vs 26.1, P = 0.001) and the MMSE score of the CAS group (26.0 vs 28.4, P = 0.01) showed statistically significant improvements. In both CAS and CEA groups, Seed-to-Voxel focusing on DMN revealed increased connectivity between medial prefrontal cortex and precuneus.

Conclusion: Both CEA and CAS are associated with an improvement in neurocognitive performance and reorganization of functional connectivity, including DMN.

Addition of low-dose liraglutide to insulin therapy is useful for glycaemic control during the peri-operative period: effect of glucagon-like peptide-1 receptor agonist therapy on glycaemic control in patients undergoing cardiac surgery (GLOLIA study)

AIM

To test the hypothesis that the addition of a glucagon-like peptide-1 receptor agonist that can decrease glucose levels without increasing the hypoglycaemia risk will achieve appropriate glycaemic control during the peri-operative period.

METHODS

We studied 70 people with Type 2 diabetes who underwent elective cardiac surgery. Participants were randomized to either an insulin-alone or an insulin plus liraglutide 0.6 mg/day group. We evaluated average M values, which indicated the proximity index of the target glucose level from day 1 to day 10.

RESULTS

The average M value in the liraglutide plus insulin group was significantly lower than that in the insulin-alone group (liraglutide plus insulin 5.8 vs insulin-alone 12.3; P < 0.001). The frequency of insulin dose modification in the liraglutide plus insulin group was significantly lower than that in the insulin-alone group (odds ratio 0.19, 95% CI 0.08-0.49; P < 0.001). The frequency of hypoglycaemia in the liraglutide plus insulin group tended to be lower than that in the insulin-alone group (odds ratio 0.57, 95% CI 0.15-2.23; P = 0.21).

CONCLUSIONS

The results of this study showed that the addition of low-dose liraglutide to insulin achieved lower M values than insulin alone, suggesting that the addition of low-dose liraglutide may achieve better glycaemic control during the peri-operative period. (Clinical trials registry no.: UMIN 000008003).

Abstract WP342: Activate the Pentose Phosphate Pathway to Reduce the Cerebral Ischemia/Reperfusion Injury: The Impact of Heat Shock Protein 27 Phosphorylation

Introduction: Based on metabolomics with gas chromatography-mass spectrometry, we showed that pentose phosphate pathway (PPP) is activated during cerebral ischemia and reperfusion in rat cerebral cortex. Especially, heat shock protein 27 (HSP27) phosphorylation seems to play an important role in activating glucose 6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in PPP. To confirm the hypothesis that HSP27 phosphorylation can be a potential target for the treatment of ischemic stroke, we used KU55933 and geranylgeranylacetone (GGA). KU55933 is the inhibitor of ataxia telangiectasia mutated kinase (ATMK), inhibiting the phosphorylation of HSP27. GGA can induce the expression of HSP families in various organs.

Methods: First, 10 μl of KU55933 or DMSO was injected into the lateral ventricle of male Wistar rats (n=5 each). One hour after the injection, 1.5-h middle cerebral artery occlusion (MCAO) and following 24-h reperfusion were performed to evaluate the effect. Next, intracerebroventricular (ICV) injection of 10 μl of GGA or DMSO was performed 3-h prior to 1-h MCAO/24-h reperfusion. Infarct size, immunoblotting, G6PD activity, and protein carbonyl indicating protein oxidation, were examined.

Results: ICV injection of KU-55933 significantly reduced the phosphorylated HSP27 (pHSP27) and G6PD activity (Fig. 1A and B). In addition, it increased the infarct size and the protein carbonyl (Fig. 1 C and D). In contrast, ICV injection of GGA increased both HSP27 and pHSP27, which resulted in significant reduction of the infarct size (19.9% vs 31.3%, p<0.01) (Fig. 1 E and F).

Conclusions: ATMK contribute the antioxidative effect with phosphorylation of HSP27 during cerebral ischemia/reperfusion. GGA may be a potential therapeutic drug for ischemic stroke. Further studies are required prior to clinical application, including investigation that use more convenient route of administration; and that evaluate the effect of GGA administration after MCAO.

Abstract TP569: The Evaluation of Cognitive Function Using Neural Network Analysis Before & After Revascularization Surgery for Internal Carotid Artery Stenosis

Background: Internal carotid artery stenosis (ICS) can lead to cognitive impairment as well as ischemic stroke. Although carotid revascularization surgery, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS), can prevent future strokes, the effect of revascularization on cognitive function is controversial. In recent years, the analysis of functional connectivity (FC) in resting-state functional MRI (rs-fMRI) has been used to investigate the effects of cognitive interventions. In this study, cognitive function is evaluated in ICS patients undergoing revascularization surgery with rs-fMRI.

Methods: A prospective study was conducted among 17 ICS patients who were expecting revascularization surgery. Cognitive assessment, including the Mini-Mental State Examination (MMSE), the Frontal Assessement Battery (FAB), and the Japanese version of the Montreal Cognitive Assessment (MoCA-J) and rs-fMRI were administered ≤ 1 week preoperatively and postoperatively at 3 months. For the analysis of FC, a seed region was placed in the posterior cingulate cortex (PCC) associated with cognitive function.

Results: After revascularization surgery, significant improvement in the score of MMSE (28.1 vs 29.1, P = 0.01) and MoCA-J (24.0 vs 26.7, P = 0.001) was found. No significant difference was found in the score of the FAB (16.2 vs 16.8, P = 0.09) between before and after surgery. According to the analysis of FC, ICS patients showed increase of connectivity between PCC and posterior cingulate gyrus, and between PCC and precuneus postoperatively at 3 months.

Conclusion: Revascularization surgery for ICS improves cognitive function. The cognitive improvement may be partly attributed to the increase of connectivity between PCC and posterior cingulate gyrus/precuneus.

Abstract TP154: Characteristics and Surgical Outcome of Patients With Carotid Stenosis Resistant to Medical Therapy

Background: The recent progress of medical therapy has made the surgical indication for carotid artery stenosis more stringent. Therefore, surgical outcome of patients resistant to medical therapy were compared with those non-resistant to medical therapy.

Methods: Between August 2006 and September 2017, 320 consecutive carotid revascularizations (CEA/CAS) were performed in our institute. Resistant (R) group was defined as patients with crescendo TIA, repeated TIA/infarction despite of medical therapy (n=15) or patients with symptomatic mobile plaque (n=5) (total 18; 2 patients overlapped). Other patients with symptomatic (116) and asymptomatic (186) stenosis were defined as non-resistant (N) group (total 302). Clinical characteristics, magnetic resonance (MR) plaque imaging, plaque pathology, and long-term outcomes with survival analysis were investigated.

Results: 13 CEA and 5 CAS were performed in R group. 181 CEA and 121 CAS were performed in N group. The periprocedural stroke & death rate was higher in R group (1/18 [5.6%]; CEA 0/13, CAS 1/5 [20%]) than in N group (9/302 [3.0%]; CEA 4/181 [2.2%], CAS 5/121 [4.1%]) but no significant difference was observed. Signal intensity ratio of plaque relative to sternocleidomastoid muscle was significantly higher in R group than in N group (1.9 vs 1.5, p = 0.007; Fig. 1A) in MR plaque imaging study, which was consistent with intraplaque hemorrhage in pathological findings of R group. Estimates of the 4-year event rate of primary end point (stroke/death/MI within 30 days, and any ipsilateral stroke thereafter) using competing risk analysis were 18% for R group and 4.5% for N group (P = 0.022; Fig. 1B). ALL recurrence occurred after CAS.

Conclusion: The resistance to medical therapy was likely to be due to severe intraplaque hemorrhage, which might explain relatively poor outcome of CAS in R group. Appropriate indication is critical for good outcome of R group.

MicroRNA regulating stanniocalcin-1 is a metastasis and dissemination promoting factor in glioblastoma

BACKGROUND

MicroRNAs (miRs) regulate many biological processes, such as invasion, angiogenesis, and metastasis. Glioblastoma (GBM) patients with metastasis/metastatic dissemination have a very poor prognosis; therefore, inhibiting metastasis/metastatic dissemination has become an important therapeutic strategy for GBM treatment.

METHODS

Using 76 GBM tissues, we examined the expression levels of 23 GBM-related miRs and compared the miRs' expression levels between GBMs with metastasis/metastatic dissemination and GBMs without metastasis/metastatic dissemination. Using the bioinformatics web site, we searched the target genes of miRs. To analyze the function of target gene, several biological assays and survival analysis by the Kaplan-Meier method were performed.

RESULTS

We found that eight miRs were significantly decreased in GBM with metastasis/metastatic dissemination. By the bioinformatics analysis, we identified stanniocalcin-1 (STC1) as the most probable target gene against the combination of these miRs. Four miRs (miR-29B, miR-34a, miR-101, and miR-137) have predictive binding sites in STC1 mRNA, and mRNA expression of STC1 was downregulated by mimics of these miRs. Also, mimics of these miRs and knockdown of STC1 by siRNA suppressed invasion in GBM cells. GBM with metastasis/metastatic dissemination had significantly higher levels of STC1 than GBM without metastasis/metastatic dissemination. Finally, Kaplan-Meier analysis demonstrated that GBMs with high STC1 level had significantly shorter survival than GBMs with low STC1 level.

CONCLUSIONS

STC1 may be a novel metastasis/metastatic dissemination promoting factor regulated by several miRs in GBM. Because STC1 is a secreted glycoprotein and functions via the autocrine/paracrine signals, inhibiting STC1 signal may become a novel therapeutic strategy for GBM.

Stent Expansion and In-Stent Thrombus Sign in the Trevo Stent Retriever Predict Recanalization and Possible Etiology During Mechanical Thrombectomy: A Case Series of 50 Patients with Acute Middle Cerebral Artery Occlusion

BACKGROUND

Interaction between the stent retriever and clot is a key factor for recanalization during mechanical thrombectomy. The aim of this study was to evaluate the association between radiographically apparent features during thrombectomy and angiographic outcomes using the Trevo stent retriever with a fully radiopaque strut.

METHODS

We retrospectively reviewed 50 patients with acute middle cerebral artery occlusion who were treated with the Trevo. Patients were divided into groups that achieved (first-pass recanalization group, n = 21) or did not achieve (non-first-pass recanalization group, n = 29) a modified Thrombolysis in Cerebral Ischemia score of 2b or 3 with the first-pass procedure. Patients were also divided into a thromboembolic (n = 39) and atherosclerotic (n = 11) group by occlusion etiology. We evaluated radiographic findings of the Trevo's strut (e.g., degree of stent expansion and filling defect of the thrombus in the strut [in-stent thrombus sign]) during the first-pass procedure.

RESULTS

Median stent expansion was significantly greater in the first-pass recanalization group than in the non-first-pass recanalization group (60% vs. 34%; P < 0.01) and in the thromboembolic group than in the atherosclerotic group (45% vs. 31%; P < 0.01). The receiver operator characteristic curve showed moderate capacity for prediction of recanalization and etiology, with an area under the curve of 0.83 and 0.73, respectively. In-stent thrombus sign was significantly more common in the thromboembolic group than in the atherosclerotic group (86% vs. 10%; P < 0.01).

CONCLUSIONS

Greater stent expansion was associated with recanalization after thrombectomy. The in-stent thrombus sign may be useful for etiology prediction. These radiographic findings could provide useful real-time feedback during procedures, reflecting clot-stent interaction.

Novel Segmentation of Placed Coils in the Treatment of Cavernous Sinus Dural Arteriovenous Fistulas Provides a Reliable Predictor of the Long-Term Outcome in Abducens Nerve Palsy

OBJECTIVE

Abducens nerve palsy (ANP) after transvenous embolization (TVE) for cavernous sinus (CS) dural arteriovenous fistulas (DAVFs) sometimes persists. The aim of this study was to assess the correlation between the coil mass and the long-term outcome of ANP after TVE.

METHODS

Between January 2008 and July 2016, 33 patients with a CS DAVF underwent TVE at our institute. On the basis of the relationship to the internal carotid artery (ICA), we divided the lateral part of the CS into the following 3 portions: anterolateral, anterolateral to the anterior bend of the ICA; middle-lateral (ML), lateral to the horizontal segment of the ICA; and posterolateral, posterolateral to the posterior bend of the ICA.

RESULTS

ANP persisted in 4 patients. The number of coils (35.3 vs. 21.9 coils; P = 0.04), coil volume (198.4 vs. 103.6 mm³; P = 0.03), and coil volume in the ML (54.9 vs. 20.3 mm³; P = 0.01) were significantly greater in the ANP group than in the non-ANP group. In the logistic regression analysis, only the ML coil volume was significantly associated with the persistence of ANP (P = 0.04). Based on the receiver operating characteristic curve, the optimal cutoff value of the ML coil volume was 27.9 mm³ (sensitivity, 100%; specificity, 72.4%).

CONCLUSIONS

Overpacking in the ML of the CS should be avoided to prevent persistent ANP. The cutoff value of the ML coil volume may provide a good guide for the practical use of TVE for CS DAVFs.

Pentose phosphate pathway activation via HSP27 phosphorylation by ATM kinase: A putative endogenous antioxidant defense mechanism during cerebral ischemia-reperfusion

Molecular mechanism underlying ischemic stroke remains poorly understood. We previously reported glucose 6-phosphate dehydrogenase (G6PD) activity in pentose phosphate pathway (PPP) is activated via heat shock protein 27 (HSP27) phosphorylation at serine 85 (S85) by ataxia telangiectasia mutated (ATM) kinase during cerebral ischemia. This mechanism seems to be endogenous antioxidative system. To determine whether this system also works during reperfusion, we performed comparative metabolic analysis of reperfusion effect on metabolism in rat cortex using middle cerebral artery occlusion (MCAO). Metabolic profiling using gas-chromatography/mass-spectrometry analysis showed changes in metabolic state that depended on reperfusion time. Enrichment analysis showed PPP was significantly upregulated during ischemia-reperfusion. Significant increases in fructose 6-phosphate and ribulose 5-phosphate after reperfusion also suggested enhancement of PPP. In relation to PPP, ischemia-reperfusion induced an increase of up to 69-fold in HSP27 transcripts after 24-h reperfusion. Immunoblotting showed gradual increase in HSP27 protein and marked increase in HSP27 phosphorylation (S85) that were time-dependent (4.5-fold after 24-h reperfusion). G6PD activity was significantly elevated after 1-h MCAO (20%), reduced after 1-h reperfusion, increased gradually thereafter and significantly elevated after 24-h reperfusion. The NADPH/NAD⁺ ratio displayed similar increasing pattern. Intracerebroventricular injection of ATM kinase inhibitor (KU-55933) significantly reduced HSP27 phosphorylation and G6PD activity, significantly increased protein carbonyl, and resulted in increase in infarct size (100%) 24-h after reperfusion following 90-min MCAO. Consequently, G6PD activation via HSP27 phosphorylation by ATM kinase may be part of endogenous antioxidant defense neuroprotection mechanism that is activated during ischemia-reperfusion. These findings have important implications for treatment of stroke.

Focal hyperintensity in the dorsal brain stem of patients with cerebellopontine angle tumor: A high-resolution 3 T MRI study

Focal hyperintensity (FHI) in the dorsal brain stem on T2-weighted images of patients with cerebellopontine angle (CPA) tumor was thought to indicate degeneration of the vestibular nucleus and to be specific to vestibular schwannoma. The purpose of this study was to evaluate FHI by using high-resolution 3 Tesla magnetic resonance imaging (3 T MRI) and the relation to clinical characteristics. We retrospectively reviewed the clinical data and MRI of 45 patients with CPA tumors (34 vestibular schwannomas and 11 other tumors). FHI in the dorsal brain stem was found in 25 (55.6%) patients (20 vestibular schwannomas and 5 other tumors). For the vestibular schwannomas, the factors contributing to positive FHI were age (p = 0.025), max CPA (p =  < 0.001), hearing ability (P = 0.005), and canal paresis (p =  < 0.001) in the univariate analysis. Multivariate regression analysis showed that max CPA (p = 0.029) was a significant factor of positive FHI. In other CPA tumors, these factors were not significant predictors. With the use of 3 T MRI, FHI was observed more frequently than previously reported. Our results suggest that FHI is not a specific indicator of vestibular schwannoma and is related to not only vestibular function but also other factors.

Effects of monthly feedback of VFA measured by dual BIA method in Japanese patients with obesity: a randomized controlled study

Objective

To investigate the effects of monthly feedback of changes in visceral fat area (VFA) as measured by dual bioelectrical impedance analysis method and the importance of VFA in individuals with obesity.

Methods

Thirty‐eight Japanese patients with obesity underwent VFA measurements. The feedback group was given feedback on VFA measurements each month for 4 months. The control group underwent VFA measurements at the beginning and end of the study but was not informed of the results. All the study participants completed eating behaviour and weight efficacy lifestyle questionnaires.

Results

Mean age was 53.9 (14.3) years; mean body mass index was 30.6 (4.3) kg m⁻². At the 4‐month follow‐up, there was no significant difference in VFA reduction between the control and feedback groups (−4.4% vs. −3.0%; 95% CI, −3.8 to 5.5). In post‐hoc analysis using the overall group irrespective of allocation, changes of eating style were significantly associated with a reduction in VFA at 4 months (p = 0.034).

Conclusions

Monthly feedback on changes in VFA does not reduce VFA. More frequent feedback may be required. In post‐hoc analysis, changes of eating style were associated with a reduction in VFA.

Early endovascular stenting for extracranial carotid artery dissection with angiographic flow stasis: A series of four cases

Extracranial carotid artery dissection is a major cause of ischemic stroke in young patients. Progressive stroke or recurrent ischemic symptoms may occur despite adequate medical treatment. Our treatment policy for these conditions is based on the fact that immediate vascular reconstruction is necessary in the cases with angiographic flow stasis in the true lumen beyond the dissection site. We report our experiences with four consecutive extracranial carotid artery dissections successfully treated with early endovascular stenting and discuss the indication of this treatment with a special emphasis on the angiographic findings.

Successful cerebral thrombectomy for a nonagenarian with stroke in the subacute phase after transcatheter aortic valve implantation

BACKGROUND

Thromboembolic events are infrequent but serious complications of transcatheter aortic valve implantation (TAVI), occurring in 2.3-10% of the patients. However, the cause of post-TAVI stroke is unclear.

CASE DESCRIPTION

A 90-year-old female underwent transfemoral-TAVI for severe aortic stenosis. Ten days later, she presented with an ischemic stroke of the left middle cerebral artery territory due to new-onset atrial fibrillation (NOAF). She underwent emergent endovascular thrombectomy with good reperfusion approximately 6 hours after onset of symptoms. At hospital discharge, her National Institutes of Health Stroke Scale score was 11.

CONCLUSIONS

Although NOAF is rare during the subacute phase of TAVI, in this patient it might be the cause of her stroke. This finding suggests that dual antiplatelet therapy alone may be insufficient in the prevention of stroke after TAVI. Nonetheless, this case demonstrates the efficacy and safety of endovascular thrombectomy in patients with acute ischemic stroke caused by NOAF after TAVI.

Magnetic Resonance Spectroscopy Findings in Patients with Dural Arteriovenous Fistulas: Three Case Reports

BACKGROUND

Magnetic resonance spectroscopy (MRS) is a potentially useful modality for evaluating brain metabolites in patients with dural arteriovenous fistula (dAVF). Here we describe a different pattern of MRS-based cerebral metabolism findings in patients with dAVF.

CASE DESCRIPTIONS

We performed MRS in 3 patients with transverse sigmoid sinus dAVF associated with cortical venous reflux. In case 1, which was associated with vasogenic edema on T2-weighted magnetic resonance imaging (MRI), decreased preoperative N-acetylaspartate (NAA)/creatine (Cr) and myo-inositol (mIns)/Cr and increased lactate (Lac)/Cr ratios improved after treatment. In case 2, a decreased preoperative NAA/Cr ratio improved after treatment. These 2 patients presented with seizures. In case 3, the patient presented with headache and showed no metabolic changes on preoperative or postoperative MRS.

CONCLUSIONS

Our results suggest that patients with dAVF can be classified based on a combination of metabolic and signal changes seen on T2-weighted MRI. MRS may allow significantly expanded evaluation of the metabolic changes associated with dAVF for appropriate classification and management.

Combined metabolic and transcriptional profiling identifies pentose phosphate pathway activation by HSP27 phosphorylation during cerebral ischemia

The metabolic pathophysiology underlying ischemic stroke remains poorly understood. To gain insight into these mechanisms, we performed a comparative metabolic and transcriptional analysis of the effects of cerebral ischemia on the metabolism of the cerebral cortex using middle cerebral artery occlusion (MCAO) rat model. Metabolic profiling by gas-chromatography/mass-spectrometry analysis showed clear separation between the ischemia and control group. The decreases of fructose 6-phosphate and ribulose 5-phosphate suggested enhancement of the pentose phosphate pathway (PPP) during cerebral ischemia (120-min MCAO) without reperfusion. Transcriptional profiling by microarray hybridization indicated that the Toll-like receptor and mitogen-activated protein kinase (MAPK) signaling pathways were upregulated during cerebral ischemia without reperfusion. In relation to the PPP, upregulation of heat shock protein 27 (HSP27) was observed in the MAPK signaling pathway and was confirmed through real-time polymerase chain reaction. Immunoblotting showed a slight increase in HSP27 protein expression and a marked increase in HSP27 phosphorylation at serine 85 after 60-min and 120-min MCAO without reperfusion. Corresponding upregulation of glucose 6-phosphate dehydrogenase (G6PD) activity and an increase in the NADPH/NAD⁺ ratio were also observed after 120-min MCAO. Furthermore, intracerebroventricular injection of ataxia telangiectasia mutated (ATM) kinase inhibitor (KU-55933) significantly reduced HSP27 phosphorylation and G6PD upregulation after MCAO, but that of protein kinase D inhibitor (CID755673) did not affect HSP27 phosphorylation. Consequently, G6PD activation via ischemia-induced HSP27 phosphorylation by ATM kinase may be part of an endogenous antioxidant defense neuroprotection mechanism during the earliest stages of ischemia. These findings have important therapeutic implications for the treatment of stroke.

The clinical significance of cysteine dioxygenase type 1 methylation in Barrett esophagus adenocarcinoma

Methylation of cysteine dioxygenase type 1 (CDO1) gene, a tumor suppressor gene, has been studied in various cancers; however, there is no information regarding Barrett esophagus cancer. In this study, the clinical significance of CDO1 methylation in Barrett esophagus adenocarcinoma (BEA) was clarified. CDO1 gene promoter methylation was analyzed for DNA from the patient's specimens using quantitative methylation-specific polymerase chain reaction. Thirty-eight BEA patients who underwent resection were identified between 2000 and 2014. Hypermethylation of CDO1 gene was demonstrated to be frequently recognized even at early stage in BEA by quantitative methylation-specific polymerase chain reaction. In BEA, there is a robust prognostic difference between stage I and stage II/III/IV with regard to 5-year relapse-free survival (P = 0.0016) and 5-year overall survival (P = 0.0024), and the tumor size separated by 7 cm was also a prognostic factor. There was significant difference in CDO1 gene methylation according to the tumor size (P = 0.036). BEA patients with CDO1 gene methylation were shown marginally significantly poorer prognosis (P = 0.054) than otherwise patients. In conclusion, higher CDO1 gene methylation was seen in BEA at earlier stage than in squamous cell carcinoma, and it may account for aggressive phenotype of BEA.

Abstract WP81: Prediction of Cerebral Aneurysm Growth Using Original Magnetic Resonance Imaging-based Computational Fluid Dynamics Tool

Background: Cerebral aneurysm growth is supposed to often precede aneurysm rupture. To predict aneurysm growth for unruptured aneurysms is still difficult by means of recently well-developed commercially available computational fluid dynamic (CFD) software.

Purpose: To detect the possible factor contributing to for the aneurysm growth with our originally developed CFD tool.

Methods: We retrospectively reviewed the aneurysms that were treated between April 2013 and March 2016 at our institute by surgical clipping or endovascular coiling with the reason of its growth (growth group). In contrast, we extracted unruptured aneurysms that had experienced no growth for at least five years (non- growth group). Time of flight (TOF) - magnetic resonance (MR) imaging data of them were converted to the three- dimenstional (3D) vessel geometric data and three hemodynamic indices: stream line (SL), wall shear stress (WSS), oscillatory shear index (OSI), were calculated with lattice Boltzmann method and compared between the two groups.

Results: Six growth aneurysms and 5 non-growth aneurysms were analyzed in this study. In the growth group, mean initial aneurysms size was 4.7mm and increased to 6.2mm after mean follow up of 33.4 months. In the non-growth group, mean aneurysm size was 5.8mm. Analyses of flow dynamics were successfully done in all cases. In all six enlarged aneurysms, WSS was increased temporally at the early diastolic phase on the focal aneurysmal sac where the aneurysms would enlarge in the future (Fig. A,B). Furthermore, in four of them, focal increase in WSS formed crescent-like shape surrounding low WSS (Inset in Fig. A). In contrast, WSS was not increased even at the early diastolic phase in three of five non-enlarged aneurysms. The SL or OSI showed no specific differences between the two groups.

Conclusion: Focal increase of WSS, some of them formed crescent-like shape, at the early diastolic phase may be the possible factor for the aneurysm enlargement in future.

Abstract WMP77: Combination of Metabolic and Transcriptional Profiling Identifies Pentose Phosphate Pathway Activation by Heat Shock Protein 27 Phosphorylation During Cerebral Ischemia

Objectives: The metabolic pathophysiology of ischemic stroke remains poorly understood. We performed a comparative omics analysis to identify the effects of cerebral ischemia on metabolism of cerebral cortex in the rat model with middle cerebral artery occlusion (MCAO).

Methods: MCAO was induced with suture occlusion technique. After the desired period of MCAO (30, 60, 120min), the rats were sacrificed. Tissue samples from the ischemic lesion were collected. Sham operated rats were treated in the same way except MCAO. Water-soluble metabolites were extracted and measured by gas-chromatography/mass-spectrometry (GC/MS). The obtained data were analyzed using multivariate statistics to explore metabolic pathways involved in ischemia. The associated metabolic enzymes were investigated with real-time polymerase chain reaction (RT-PCR) and Immunoblot analysis.

Results: Metabolic profiling by GC/MS analysis showed clear separation between the ischemia and control group (Figure A, B). The decrease of fructose 6-phosphate and ribulose 5-phosphate suggested enhancement of the pentose phosphate pathway (PPP) during cerebral ischemia. Transcriptional profiling by microarray hybridization indicated that Toll-like receptor and mitogen-activated protein kinase (MAPK) signaling pathway were upregulated during cerebral ischemia. In relation to PPP, upregulation of heat shock protein 27 (HSP27) was observed in the MAPK signaling pathway and was confirmed through RT-PCR. Immunoblotting showed a slight increase in HSP27 protein expression and a marked increase in HSP27 phosphorylation (FigureC). Corresponding upregulation of glucose 6-phosphate dehydrogenase (G6PD) activity and an increase in the NADPH/NAD+ ratio were also observed (Figure D, E).

Conclusions: G6PD activation via ischemia-induced HSP27 phosphorylation may be part of an endogenous antioxidant neuroprotection mechanism during the earliest stages of ischemia.

Abstract TP116: Perioperative Assessment of Cerebral Perfusion Territories Through Arterial Spin Labeling Magnetic Resonance Imaging in Carotid Stenosis

Backgroud: Territorial arterial spin labeling (TASL) is a MRI technique that permits independent labeling of major individual feeding vessels and noninvasive visualization of their perfusion territories.

Objective: The objectives of this study were to use TASL to assess perioperative changes in the perfusion territories of the internal carotid arteries (ICAs) in carotid stenosis patients and to investigate the usefulness of this technique.

Methods: Thirty-two patients underwent TASL and SPECT before and after carotid endarterectomy (CEA) or carotid artery stenting (CAS). ICA perfusion volume was calculated using TASL images. ICA flow was measured during CEA, both before and after reconstruction, using electromagnetic flow meter.

Results: In most cases, preoperative asymmetry ( Fig. A ) of ICA perfusion volume improved postoperatively ( Fig B ) (red, rt ICA; green, lt ICA; blue, VA-BA). We classified patients into the following two groups: (1) an elevated CBF group (CBF increase after surgery ≥50%, n=4) and (2) a stable CBF group (CBF increase after surgery <50%, n=28). ICA perfusion volume increased significantly after surgery in the stable CBF group (291.1±89.0cm 3 versus 396.4±40.9cm 3 , p<0.0001) but did not increase significantly in the elevated CBF group (246.4±103.2cm 3 versus 268.7±107.7cm 3 ) ( Fig. C ). However, ICA flow increased significantly after reconstruction in both the elevated CBF group (54.0±58.2ml/min → 177.7±25.4ml/min) and the stable CBF group (85.7±50.0ml/min → 171.8±56.1ml/min) (p<0.0001) ( Fig. D ).

Conclusion: TASL clearly demonstrated that CEA and CAS elicited increases in the perfusion volumes of stenotic ICAs, which resulted in equalization of the perfusion volumes of the left and right ICA. In the elevated CBF group, however, ICA perfusion volume increased slightly, despite marked increase in ICA flow. These findings suggest that an imbalance between these parameters plays an important role in the pathophysiology of hyperperfusion.

Abstract TP319: Duplex Assisted Carotid Artery Stenting Without Administration of Contrast Media

Background: Conventional carotid artery stenting (CAS) with administration of contrast media carries a risk of adverse reactions such as contrast media-induced nephropathy or an allergic reaction.

Objective We aimed to present a novel technique, that is, duplex-assisted CAS without administration of contrast media and validate its safety and feasibility.

Methods: Fifteen patients with severe carotid stenosis (≥70 %) associated with chronic kidney disease (CKD) (stage ≥3) or allergy to contrast media underwent duplex-assisted CAS without administration of contrast media. The embolic protection device (EPD) placed in the common carotid artery (CCA) was clearly visible on the longitudinal section (Fig. A) and was then advanced into the internal carotid artery (ICA) by duplex-guidance (Fig. B). When starting the delivery of the stent, the position of the distal stent end is confirmed by duplex monitoring (Fig. C). Postdilatation was performed after the stent (Fig. D arrowheads) deployment if enough expansion of the carotid artery was not achieved. Adequate stent position (Fig. E arrowheads) and technical success was confirmed by duplex images and intravascular ultrasound (Fig. F). Conventional CAS was also performed in 165 patients and used as the control group.

Results: The technical success rate was 100 % in duplex-assisted CAS group. Combined stroke or death rates during the post-procedural period did not differ significantly between the duplex assisted CAS group (0/15, 0 %) and conventional CAS group (4/165, 2.4 %). None of the 14 patients with CKD in the duplex-assisted CAS group experienced further deterioration of renal function.

Conclusion: This method seemed to be a safe and effective treatment for patients with CKD or an allergy to contrast media. The most important factor for the indication of duplex-assisted CAS was to obtain the clear visualization of the luminal narrowing with minimal calcification on the longitudinal section of the duplex ultrasonography.

Abstract WP150: BeamSAT MRI Help to Identify Patients at Risk for Intolerance to Temporary Internal Carotid Artery Occlusion During CEA and CAS

Introduction: Pencil Beam type presaturation (BeamSAT) pulse on a major cervical vessel enables selective suppression of blood flow signal of the applied vessel in MR angiography (MRA). By subtracting the BeamSAT pulse-added MRA of an internal carotid artery (ICA) from conventional MRA, only the contralateral ICA image (SubBeamSAT image) can be obtained (Figure A, B). In this way, an ICA-selective MRA with more physiologial flow pattern can be obtained, because it requires no powerful injection of contrast medium.

Purpose: The aim of this study was to investigate whether preoperative assessment of the flow of Acom/A1 by SubBeamSAT image and posterior communicating artery (Pcom) by conventional MRA could identify patients at risk for intolerance to intraoperative temporary ICA occlusion.

Method: 29 patients who underwent carotid endarterectomy (CEA) (n = 17) or carotid artery stenting (CAS) (n = 12) were enrolled in the current study. All patients underwent the SubBeamSAT images and conventional MRA pre- and post-operatively. Response to ICA temporally occlusion was recorded during the revascularization procedure.

Results: Among twenty-nine patients, 4 patients who demonstrate neither the Acom/A1 flow on SubBeamSAT image (Figure. B) nor Pcom flow on MRA showed intolerance. In contrast, the remaining 25 patients who demonstrated Acom/A1 (Figure. A) and/or Pcom flow showed tolerance. Intolerance to ICA occlusion was excellently predicted by visualization of collateral flow via Acom and Pcom (specificity: 100%, sensitivity: 100%, p=0.00004).

Conclusions: SubBeamSAT image is useful for evaluating the flow of Acom from A1 portion of the healthy side to A2 portion of the contralateral side, which is often difficult to evaluate with conventional MRA. With the SubBeamSAT image, it is feasible to evaluate the Acom/A1 flow accurately. In conclusion, SubBeamSAT image enables excellent prediction for the intolerance to temporary ICA occlusion.

Mechanical Thrombectomy Using the Trevo ProVue in 50 Consecutive Patients with Anterior Circulation Stroke: A Single-Center Experience after Approval of the Stent Retriever in Japan

Mechanical thrombectomy using the stent retriever has been proven to be effective for select patients with acute ischemic stroke. We evaluated our early experience using the device after its approval in 2014 in Japan, with a special emphasis on the occlusion site. Fifty consecutive endovascular revascularization procedures for treating anterior acute large vessel occlusion were performed using the Trevo ProVue as the first-line device at our institute between April 2015 and March 2016. Focusing on the involvement of the M1-M2 bifurcation with deployment or retrieval of the stent retriever, we regarded the middle cerebral artery M1 mid-portion as the boundary and divided the cases into proximal (n = 26) and distal (n = 24) groups. We assessed the overall clinical outcome and compared the outcome between the two groups. Among 50 patients (median age, 80 years; National Institutes of Health Stroke Scale score (NIHSS) score, 20), successful (modified Thrombolysis in Cerebral Infarction score (TICI) 2b or 3) or complete revascularization (TICI 3) was achieved in 41 patients (82%; 88% in the proximal group vs 75% in the distal group, P = 0.28) and in 27 patients (54%; 73% vs 33%, P = 0.01), respectively. Symptomatic intracranial hemorrhage occurred in three patients (6%; 4% vs 8%, P = 0.60). A good outcome (mRS score 0 to 2) was obtained in 25 patients at 90 days (50%; 54% vs 46%, P = 0.78). Mechanical thrombectomy using the Trevo ProVue was safe and effective in patients with acute cerebral artery occlusion, especially for proximal occlusions. The efficacy of the procedure for distal occlusions was somewhat inferior to those for proximal occlusions, which might be resolved by next generation devices.

Acute Ischemic Stroke Involving Both Anterior and Posterior Circulation Treated by Endovascular Revascularization for Acute Basilar Artery Occlusion via Persistent Primitive Trigeminal Artery

We report a case of acute ischemic stroke involving both the anterior and posterior circulation associated with a persistent primitive trigeminal artery (PPTA), treated by endovascular revascularization for acute basilar artery (BA) occlusion via the PPTA. An otherwise healthy 67-year-old man experienced sudden loss of consciousness and quadriplegia. Magnetic resonance imaging showed an extensive acute infarction in the right cerebral hemisphere, and magnetic resonance angiography showed occlusion of the right middle cerebral artery (MCA) and BA. Because the volume of infarction in the territory of the right MCA was extensive, we judged the use of intravenous tissue plasminogen activator to be contraindicated. Cerebral angiography revealed hypoplasia of both vertebral arteries and the presence of a PPTA from the right internal carotid artery. A microcatheter was introduced into the BA via the PPTA and revascularization was successfully performed using a Merci Retriever with adjuvant low-dose intraarterial urokinase. After treatment, his consciousness level and right motor weakness improved. Although persistent carotid-vertebrobasilar anastomoses such as a PPTA are relatively rare vascular anomalies, if the persistent primitive artery is present, it can be an access route for mechanical thrombectomy for acute ischemic stroke.

Minimum Transpetrosal Retrolabyrinthine Approach for Revascularization of Posterior Cerebral Artery: Operative Nuance

BACKGROUND

Revascularization of the posterior cerebral artery (PCA) can be essential for treating complex cerebral aneurysms in the posterior circulation, and it is considered technically challenging. To help decrease the difficulty of this technique, we developed the minimum transpetrosal approach (MTPA).

OBJECTIVE

The technical nuances of the MTPA were innovated by cadaver head dissections and an actual clinical case.

METHODS

Four sides of the formalin-fixed cadaver heads were used to investigate if the posterior cerebral artery could be exposed with this minimum retraction of the temporal lobe in the subtemporal approach and the MTPA. By using the MTPA, 1 patient harboring a ruptured PCA aneurysm underwent superficial temporal artery-PCA anastomosis followed by isolation of the aneurysm.

RESULTS

In the cadaver head dissections, we noticed that the PCAs were difficult to expose with gentle retraction of the temporal lobe in the subtemporal approach. By performing an additional retrolabyrinthine mastoidectomy, performed as the MTPA, all 4 PCAs were easily exposed in the 4 wide surgical fields. The maximum widths of the surgical fields above and below the PCA could be successfully measured in 2 cases, which were 13.3 mm and 11.2 mm, respectively (mean, 12.3 mm). Additionally, in the actual live surgery using MTPA, the PCAs were relative easy to expose with a surgical field wide enough to perform PCA bypass, which was performed without complication.

CONCLUSION

The MTPA may be the most favorable approach for PCA bypass that can be performed easily with minimal temporal lobe retraction.