Water content for clot composition prediction in acute ischemic stroke

BACKGROUND

Mechanical thrombectomy (MT) has become the gold standard care for treating acute ischemic stroke (AIS) due to large vessel occlusion. Emerging evidence suggests that understanding the composition of clots prior to intervention could be useful for the selection of neuroendovascular techniques, potentially improving the efficacy of treatments. However, current imaging modalities lack the ability to distinguish clot composition accurately and reliably. Since water content can influence signal intensity on CT and MRI scans, its assessment may provide indirect clues about clot composition. This study aimed to elucidate the correlation between water content and clot composition using human clots retrieved from stroke patients and experimentally generated ovine clots.

MATERIALS AND METHODS

This study involved an analysis of ten clots retrieved from patients with AIS undergoing MT. Additionally, we created ten red blood cells (RBC)-rich and ten fibrin-rich ovine blood clots, which were placed in a human intracranial vascular model under realistic flow conditions. The water content and compositions of these clots were evaluated, and linear regression analyses were performed to determine the relationship between clot composition and water content.

RESULTS

The regression analysis in human stroke clots revealed a significant negative association between RBC concentration and water content. We also observed a positive correlation between water content and both fibrin and platelets in ovine blood clots. Conclusion.

Erratum to "Crossing double stent retriever technique for refractory terminal internal carotid artery occlusion" [Radiology Case Reports 17 (2022) 1848-1852]

[This corrects the article DOI: 10.1016/j.radcr.2022.03.023.].

An aggressive dural arteriovenous fistula manifested by unilateral subcortical calcification and cerebral edema: A case report

Unilateral subcortical calcifications are unique radiographic findings indicating specific focal pathologies. When the lesion is accompanied by edema, cerebral neoplasm usually leads to a differential diagnosis. This report presents a case of unilateral subcortical calcification and edema that resulted in cerebral hemorrhage and a subsequent diagnosis of an aggressive dural arteriovenous fistula. A man in his 60s presented with left hemianopsia and a progressive headache for over 6 months. Initial computed tomography revealed unilateral subcortical calcification and cerebral edema in the right occipital lobe, raising the suspicion of oligodendroglioma. However, 10 days later, a cerebral hemorrhage occurred in the lesion. Magnetic resonance imaging revealed flow void clusters and dilatation of the bilateral external carotid arteries and cortical veins, indicating a dural arteriovenous fistula. Cerebral angiography confirmed the presence of a parasagittal dural arteriovenous fistula (Borden type III). The patient was successfully treated with trans-arterial embolization using Onyx. Thus, calcifications with edema are more commonly associated with cerebral neoplasms; however, in this case, they indicated the presence of a dural arteriovenous fistula with severe corticovenous reflux. The presented case highlights the importance of recognizing these imaging features in dural arteriovenous fistulas and raises awareness of the potential danger of early hemorrhage after diagnosis. Therefore, timely evaluation of cranial vessels is essential in cases of unilateral subcortical calcification and edema to facilitate the early detection and management of aggressive dural arteriovenous fistulas.

In vitro comparison of manual and robotic endovascular thrombectomy for acute ischemic stroke

BACKGROUND

Robotic endovascular systems have the potential to reduce radiation exposure to physicians and expand timely neurointerventional access to patients in remote areas. The goal of the study was to determine the feasibility of robotic endovascular thrombectomy (EVT) in an in vitro model.

METHODS

In vitro procedures were conducted manually and robotically using the Corpath GRX robotic system in a human vascular simulator with an elastic ovine clot in the M1 segment of the left middle cerebral artery. Due to the limited device compatibility of the CorPath GRX, a simple technique with a stent retriever and guiding catheter without a balloon was used in the study. Seven robotic EVT and manual EVT were carried out in each group. Metrics including procedural time, success rate, and radiation dose were compared between the two groups.

RESULTS

In robotic EVT, the mean total preparation and procedural time was 892 s, which was significantly longer than manual operation at 357 (p = 0.0001). There was no significant difference in the success rate between the two approaches (robotic: 28.6% vs. manual 42.9%, p = 0.577). The mean radiation exposure to operating physicians was significantly lower during robotic operation compared to manual operation (0.02 μSv vs. 0.22 μSv, p < 0.0001).

CONCLUSIONS

Robotic EVT was feasible in our human vascular simulator with significantly reduced radiation exposure to the operating physicians, despite an increased length of procedure when compared to manual procedures. Future technological advancement is warranted for reducing procedural length using endovascular robotic techniques.

Devices and Techniques

This extensive review explores the intricacies of the three principal mechanical thrombectomy techniques: the stent retriever technique, contact aspiration technique, and a combined approach, and their application in managing acute ischemic stroke. Each technique operates uniquely on the thrombus, leading to differences in their efficacy. Factors including clot size, clot stiffness, vessel tortuosity, and the angle of interaction between the aspiration catheter and the clot significantly influence these differences. Clinical trials and meta-analyses have shown the overall equivalency of these techniques for the treatments of large vessel occlusion and distal medium vessel occlusions. However, there are nuanced differences that emerge under specific clinical circumstances, highlighting the absence of a one-size-fits-all strategy in acute ischemic stroke management. We emphasize the need for future investigations to elucidate these nuances further, aiming to refine procedural strategies and individualize patient care for optimal outcomes.

Hemostatic patch with ultra-strengthened mechanical properties for efficient adhesion to wet surfaces

Controlling traumatic bleeding from damaged internal organs while effectively sealing the wound is critical for saving the lives of patients. Existing bioadhesives suffer from blood incompatibility, insufficient adhesion to wet surfaces, weak mechanical properties, and complex application procedures. Here, we engineered a ready-to-use hemostatic bioadhesive with ultra-strengthened mechanical properties and fatigue resistance, robust adhesion to wet tissues within a few seconds of gentle pressing, deformability to accommodate physiological function and action, and the ability to stop bleeding efficiently. The engineered hydrogel, which demonstrated high elasticity (>900%) and toughness (>4600 kJ/m3), was formed by fine-tuning a series of molecular interactions and crosslinking mechanisms involving N-hydroxysuccinimide (NHS) conjugated alginate (Alg-NHS), poly (ethylene glycol) diacrylate (PEGDA), tannic acid (TA), and Fe3+ ions. Dual adhesive moieties including mussel-inspired pyrogallol/catechol and NHS synergistically enhanced wet tissue adhesion (>400 kPa in a wound closure test). In conjunction with physical sealing, the high affinity of TA/Fe3+ for blood could further augment hemostasis. The engineered bioadhesive demonstrated excellent in vitro and in vivo biocompatibility as well as improved hemostatic efficacy as compared to commercial Surgicel®. Overall, the hydrogel design strategy described herein holds great promise for overcoming existing obstacles impeding clinical translation of engineered hemostatic bioadhesives.

First-in-human trial of Center Wire for neuroendovascular therapy to avoid guidewire-related complications

BACKGROUND

An exchange maneuver is useful for the delivery of devices to target vessels. However, hemorrhagic complications can occur due to vessel perforation during an exchange maneuver. In addition, the exchange is often challenging due to unfavorable anatomy. Center Wire is an exchange-length wire with a nondetachable stent that was developed to improve navigation and stability during exchange maneuvers. The aim of this study is to investigate the safety and efficacy of Center Wire of the anchor wire technique during neuroendovascular treatment.

METHODS

Ten patients with intracranial aneurysms were treated after signing a Certified Review Board-approved consent. Anchor wire technique was used in all patients to navigate catheters to the target vessel for aneurysm treatment.

RESULTS

Anchor wire technique was successfully applied in all 10 cases using Center Wire. One device-related incident of vasospasm occurred which was asymptomatic. No device-related dissection, perforation, or thromboembolic events occurred. One patient had intraoperative aneurysm rupture during coil placement which was treated immediately without clinical consequences. Two patients had postoperative ischemic strokes due to thrombotic occlusion of branches originating from the aneurysm which were unrelated to the device.

CONCLUSIONS

This first-in-human trial of Center Wire demonstrated the safety and efficacy of the anchor wire technique for neuroendovascular treatment in a strictly regulated prospective registry trial.

First-in-human trial of Stabilizer device in neuroendovascular therapy

Objectives

Flow diverter or stent implantation to intracranial target lesion requires large inner diameter microcatheter navigation. The exchange method using stiff long wire is often necessary if it is difficult to navigate over the regular guidewire. However, this method has an intrinsic risk of vessel damage and may cause severe complications. We investigated the safety and efficacy of a new device, the Stabilizer device for navigation in a first-in-human clinical trial under the Certified Review Board agreement.

Materials and methods

The Stabilizer is a 320 cm length exchange wire with a stent for anchoring and is compatible with a 0.0165" microcatheter. The trial design is a prospective single-arm open-label registry. Inclusion criteria are elective flow diverter treatment or stent-assisted coiling, expected to be difficult to navigate a microcatheter with a regular micro guidewire, and obtained documented consent. The primary endpoint of the study was a hemorrhagic complication.

Results

Five patients were enrolled in this trial. The median age is 52 years, ranges from 41 to 70, and all patients were female. Three aneurysms were located on the internal carotid artery, one on the vertebral artery, and one on the basilar artery. Basilar artery aneurysm was treated by stent-assisted coiling and others were treated by flow diverter deployment. All cases successfully navigate microcatheter for the treatment by the trial method using Stabilizer device without any adverse event.

Conclusions

The results from this first-in-human consecutive five cases show the safety of the Stabilizer device in neuro-endovascular therapy for navigation of devices to the intracranial target lesion.

Endovascular Treatment of Tandem Atherosclerotic Cervical Internal Carotid Artery Occlusion in the Setting of Acute Ischemic Stroke

BACKGROUND

Among tandem occlusions, atherosclerotic cervical internal carotid artery occlusion (ACICAO) can be technically challenging and associated with its unique complications. We evaluated our experience with endovascular treatment (EVT) of ACICAO in the setting of acute ischemic stroke.

METHODS

In total, 154 consecutive patients who underwent EVT for acute anterior circulation stroke at our institute were retrospectively reviewed. Patients with tandem ACICAO were analyzed in this study. Procedures, recanalization rates, complications, and prognoses were evaluated.

RESULTS

Ten patients (6%) of all 154 patients had ACICAO. In nine (90%) of the 10 patients, cervical lesions were successfully crossed and intervened upon. Four patients underwent stenting and five underwent angioplasty alone, followed by intracranial procedure. Eight patients (80%) achieved successful recanalization following mechanical thrombectomy for intracranial occlusion. However, one patient had massive subarachnoid hemorrhage during the procedure and another patient developed massive intracranial hemorrhage after EVT, both after stenting. Four of the five patients who initially underwent angioplasty alone subsequently underwent staged endarterectomy or stenting for residual stenosis on or after the next day. The single patient in whom the cervical lesion could not be crossed and another with reocclusion after EVT underwent a rescue bypass procedure due to persistent ischemic symptoms. After 90 days, four patients (40%) were functionally independent (modified Rankin scale score 0-2).

CONCLUSIONS

Our experience suggests that EVT for ACICAO is technically feasible; however, it involves the potential risk of several significant complications. To avoid serious hemorrhagic complications, cervical lesions may be better treated with angioplasty alone first.

Acute internal carotid artery occlusion due to dissection of the paraclinoid segment: Diagnostic usefulness of angiographic findings during stent retriever deployment

Intracranial artery dissection is an uncommon but possible cause of ischemic stroke, and is usually diagnosed based on imaging findings such as mural hematoma and dissection flap. However, it is challenging to recognize the underlying dissection in cases of acute large vessel occlusion. In this report, we present a case of acute internal carotid artery occlusion, in which the underlying dissection of the paraclinoid segment was found during the thrombectomy procedure. Two thrombectomy procedures failed to recanalize the acute internal carotid artery occlusion without removing any clot. Angiography performed during a Trevo stent retriever deployment in the first pass showed obscure contrast defects in the stent strut with temporary flow restoration. In the next pass, the appearance of the contrast defects changed and a parallel linear contrast appeared on the outside of the vessel wall. These angiographic findings were identified as mural hematoma and dissection flap, indicating dissection of the paraclinoid as the cause of the occlusion. During antiplatelet loading and preparation of a dedicated intracranial stent, the Trevo stent retriever was left deployed again at the occlusion site to maintain the blood flow. After permanent stenting with an Enterprise stent, angiography revealed complete recanalization. The patient recovered fully after the procedure. In the present case, stent retriever deployment revealed the hallmarks of dissection on angiography, such as mural hematoma, dissection flap, and temporal morphological changes, by restoring the blood flow temporarily. Such angiographic findings can provide useful information on the occlusion characteristics and real-time feedback for optimal treatment strategy.

Crossing double stent retriever technique for refractory terminal internal carotid artery occlusion

Mechanical thrombectomy is highly effective for the recovery of acute ischemic stroke with large vessel occlusion. However, refractory occlusions are still encountered despite the use of currently available devices. In this article, we present a case of refractory terminal internal carotid artery occlusion treated with the "crossing double stent retriever technique." Two thrombectomy procedures with the combined technique using a stent retriever and aspiration catheter failed to recanalize the terminal internal carotid artery occlusion that involved the dominant anterior cerebral artery. We then applied the crossing double stent retriever technique as a rescue technique. Two microcatheters were advanced across the occlusion: one to the anterior cerebral artery and the other to the middle cerebral artery. First, a Trevo NXT 4 mm stent retriever was deployed from the anterior cerebral artery. Next, an additional Trevo NXT 4 mm stent retriever was deployed from the middle cerebral artery, and full immediate restoration of flow was achieved on angiography. Intraprocedural radiological images showed that the 2 microcatheters traversed different pathways, and the 2 stent retrievers completely covered the entire vessel with apparent in-stent clot sign. Both stent retrievers were then pulled back together, and a hard clot was retrieved. Subsequent angiography revealed complete recanalization. The crossing double stent retriever technique seems an effective rescue technique for treating refractory terminal internal carotid artery occlusion, especially with the anatomical feature of branching of the dominant anterior cerebral artery. This technique can facilitate the device-clot-vessel interaction by engaging the clot via 2 different device pathways.

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.

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.

Iatrogenic intracranial vessel dissection during mechanical thrombectomy rescued by emergent stenting: 2 case reports

Intracranial vessel dissection is a procedural complication associated with endovascular treatment. However, there have been few reports on its potential causes and management during mechanical thrombectomy. In approximately 250 cases of mechanical thrombectomy over the past 5 years at our institution, iatrogenic intracranial dissection occurred in 2 patients (0.8%). In this report, we described these 2 cases that were rescued through emergent stenting. Mechanical thrombectomy, using both a stent retriever and an aspiration catheter, was performed for acute middle cerebral artery M2 occlusion in Patient 1 (a 69-year-old man) and for distal M1 occlusion in Patient 2 (an 83-year-old woman). In both cases, recanalization was achieved with the procedure, but irregular stenosis developed at the initially nonoccluded, but mildly arteriosclerotic, M1, after recanalization. During the thrombectomy procedure, the aspiration catheter sifted up to the arteriosclerotic M1. In both cases, the lesions were considered vessel dissection, due to a shift of the aspiration catheter tip into the arteriosclerotic vessel wall. Repeated percutaneous angiography with antithrombotic therapy failed to improve the lesions and to maintain the antegrade blood flow. Finally, lesions in each patient were successfully rescued through the use of emergent stenting. A drug-eluting stent for coronary use was deployed in Patient 1, and an Enterprise stent was applied in Patient 2. Inadvertent shift of the aspiration catheter into arteriosclerotic vessels can cause a serious intracranial vessel dissection. When performing mechanical thrombectomy, intracranial stents need to be available as rescue treatment devices to manage refractory iatrogenic intracranial vessel dissection.

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.

An Aneurysm at the Origin of a Duplicated Middle Cerebral Artery Treated by Stent-Assisted Coiling Using the "Wrapped-Candy" Low-Profile Visualized Intraluminal Support (LVIS) Technique: A Technical Case Report and Review of the Literature

BACKGROUND

Aneurysms at the origin of a duplicated middle cerebral artery (DMCA) are quite rare. Here, we report a patient with such an aneurysm successfully treated endovascularly using our novel "wrapped-candy" low-profile visualized intraluminal support (LVIS) technique.

CASE DESCRIPTION

A 44-year-old woman underwent endovascular treatment for an unruptured wide-necked aneurysm at the origin of a DMCA that incorporated the origin of the DMCA into its neck. Stent-assisted coiling was performed using our newly developed "wrapped-candy" LVIS technique. To protect the origin of the DMCA and increase the stent metal density at the neck, an LVIS blue 3.5-mm × 22-mm stent was deployed by pushing the delivery wire aggressively to transform the visible wire components of the LVIS into a shape like "wrapped candy," maximizing the strut compaction at the neck of the aneurysm. Subsequently, the aneurysm component was coiled using a jailed microcatheter. The final procedural angiography demonstrated almost complete aneurysm occlusion with DMCA preservation.

CONCLUSIONS

Stent-assisted coiling can be a feasible treatment for an unruptured, usually wide-necked, aneurysm at the origin of a DMCA. The wrapped-candy LVIS technique may be useful in more challenging morphologies such as wide-necked aneurysms that incorporate the branch origin into the aneurysm neck.

Surgical Thromboendarterectomy for Free-Floating Thrombus Associated with Cervical Carotid Artery Dissection: A Case Report

BACKGROUND

Free-floating thrombus (FFT) of the cervical carotid artery is a rare but critical condition leading to stroke. The most common underlying pathology is atherosclerotic plaque; nonatherosclerotic pathologies are much rarer. Here we report a case of FFT associated with cervical carotid artery dissection that was successfully treated by surgical thromboendarterectomy.

METHODS

A 51-year-old man presented with headache, pain in the left neck, and amaurosis fugax. Magnetic resonance angiography revealed mild stenosis in the bifurcation of the left carotid artery. The stenotic lesion was considered as a possible dissection because of the normal appearance of the vessel 2 years ago and its clinical presentation. Oral aspirin was initiated with the diagnosis of transient ischemic attack. Two weeks later, ultrasound was planned for further examination, which demonstrated a massive FFT with intramural hematoma in the lesion. Because FFT was present despite taking aspirin, surgical thromboendarterectomy was performed to prevent further ischemic events.

RESULTS

Intraoperative findings revealed that FFT was the thrombus protruding from the intramural hematoma caused by arterial dissection. After the whole dissected layer was removed, the residual lumen was reinforced by multiple tacking sutures to prevent recurrence of dissection. No further ischemic events and recurrence occurred during the 1-year of follow-up after the surgery.

CONCLUSIONS

When managing patients with carotid artery dissection, the formation of FFT should be considered as a possible critical feature. Surgical thromboendarterectomy with intimal tacking sutures might be an option for the treatment, ensuring immediate, preventive effects against the risk of cerebral embolism.

Refractory communicating hydrocephalus after radiation for small vestibular schwannoma with asymptomatic ventriculomegaly: A case report

Communicating hydrocephalus is a known tumor-related syndrome associated with vestibular schwannoma, which can occur even in small tumor. Radiation has become a popular primary treatment option for small schwannoma; however, little is known about the efficacy and risk accompanying asymptomatic ventriculomegaly on images. We report a case of a 59-year-old woman who suffer from refractory communicating hydrocephalus after radiation for small vestibular schwannoma with asymptomatic ventriculomegaly. After the surgical removal of the tumor, hydrocephalus was gradually improved due to intermittent lumbar puncture and finally resolved without shunt placement. Surgical removal should be considered as the first option for the treatment, even if the patient is asymptomatic and the images revealed a small vestibular schwannoma with only slight ventricular enlargement.

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.

Delayed Rebleeding from Pseudoaneurysm After Mechanical Thrombectomy Using Stent Retriever Due to Small Artery Avulsion Confirmed by Open Surgery

BACKGROUND

Pseudoaneurysm after mechanical thrombectomy (MT) is rare but is one of the potential complications associated with endovascular procedures. There is limited information regarding its mechanism of formation and the potential risk of delayed bleeding.

CASE DESCRIPTION

An 84-year-old woman was admitted to our institution with right hemiplegia and global aphasia. Magnetic resonance imaging and angiography revealed occlusion of the M2 segment of the left middle cerebral artery with subtle acute ischemic change in this territory. After initiating intravenous thrombolysis, MT was performed for persistent occlusion of the M2. Successful revascularization was finally achieved with a single pass of a Trevo XP 3 mm × 20 mm stent retriever; significant deviation of the vessel occurred during withdrawal of the stent retriever. Anticoagulation was initiated after confirming resolution of a small amount of postprocedural subarachnoid hemorrhage 1 day after the procedure. However, 4 days after the procedure, computed tomography and angiography revealed a massive sylvian hematoma with de novo formation of a small pseudoaneurysm at the site where the stent retriever was deployed. Open surgery revealed a small artery avulsion at this site. The lesion was closed by microsurgical suturing.

CONCLUSIONS

Angiographic and intraoperative findings showed that the mechanism of formation of the pseudoaneurysm was small artery avulsion resulting from deviation of the vessel during withdrawal of the stent retriever. When performing MT in a tortuous distal vessel, the possibility of small artery avulsion should be kept in mind to both prevent and manage critical hemorrhagic complications.

Deploying 5 Overlapping Enterprise Stents and Coiling for Treating Hemorrhagic Vertebral Artery Dissecting Aneurysm

BACKGROUND

Reconstructive endovascular treatment is a method that can ameliorate vertebral artery dissecting aneurysm (VADA) and preserve the parent artery. Recently, 2 or 3 overlapping stents have been used to treat VADAs through the flow-diversion effect. However, little is known about the use of >3 overlapping stents for acute treatment of hemorrhagic VADA.

CASE DESCRIPTION

A 69-year-old woman was admitted to our institute with the sudden onset of a headache. Brain computed tomography revealed a subarachnoid hemorrhage. Cerebral angiography revealed a VADA in the right intracranial vertebral artery. The contralateral vertebral artery was hypoplastic; thus we performed a reconstructive endovascular procedure using multiple overlapping stents combined with coiling. We used 5 overlapping stents with the aim of preventing coil herniation, fixing the jailed microcatheter, and reinforcing flow diversion and achieved immediate occlusion of the aneurysmal component. Postoperative imaging showed no apparent infarction in the brainstem. Six months after the treatment, angiography revealed complete occlusion of the aneurysm. Therefore in this case, hemorrhagic VADA was successfully treated in the acute setting by 5 overlapping Enterprise stents and coiling, which also preserved the parent artery.

CONCLUSIONS

Reconstructive endovascular treatment using multiple overlapping stents and coiling may be a beneficial therapy for hemorrhagic VADA, especially when the contralateral vertebral artery is aplastic or hypoplastic. Using >3 overlapping stents may represent a promising, feasible technique for achieving immediate occlusion by increasing flow diversion.

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 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.

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.

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.

Abstract WP120: Long-Term Survival of Carotid Endarterectomy and Carotid Artery Stenting in Japanese Population

Introduction: According to the current guidelines, treatment for carotid stenosis with carotid endarterectomy (CEA) or carotid artery stenting (CAS) should be limited to patients with life expectancy of >3 to 5 years. We aimed to assess the long-term survival after CEA and CAS in Japanese population.

Methods: Between August 2006 and June 2015, 262 consecutive carotid revascularizations with either CEA or CAS were performed in our institute. The initial treatment was regarded as the starting point in the cases of the patients who received treatment by bilateral carotid artery stenosis or retreatment. A Kaplan-Meier life table was done and a multivariate Cox hazard model was built for the analysis of the long-term survival-associated risk factors.

Results: A total of 231 patients (CEA 142, CAS 89; mean age, 72.1 ± 7.4 y.o.), including 106 symptomatic patients, were enrolled in the current study with mean follow-up period of 52.2 months. During follow-up 37 patients (16%) died, being cancer (19%) and pneumonia (19%) the most frequent causes. Cumulative 3- and 5-year survival rates were 92% and 87%, respectively. Kaplan-Meier estimates of the 5-year survival rate were 89.8% for CEA and 81.5% for CAS (P=0.033) (Figure Left). Cox regression model showed independent risk factors related to survival were age (Hazard ratio [HR], 1.08/year [95%CI, 1.03-1.13]; p = 0.003) (Figure Right)and CAS (HR, 2.3 [95%CI, 1.2-14.6]; p = 0.012). Presence of symptom was not associated with the long-term survival. No death due to stroke occurred.

Conclusion: The life-expectancy of patients in the current study satisfies the current guidelines and the long-term survival was associated with age and CAS. The inclusion of higher risk patients in the CAS group may have been the reason for CAS being a risk factor.

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.

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.

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 WP12: Impact of the Introduction of Endovascular Treatment on Acute Ischemic Stroke Therapy in a Rural Broad Region in Japan

Background: Endovascular treatment (EVT) has been proven to be effective for selected patients with acute ischemic stroke (AIS). We evaluated the effect of the introduction of EVT on outcome of AIS therapy in a rural broad region in Japan, covering an area within a radius of 80km by air ambulance.

Methods: Between January 2014 and July 2016, 210 consecutive patients with acute large vessel occlusion (189 patients in the anterior circulation and 21 in the posterior circulation) admitted to our institute were analyzed. EVT was introduced into the AIS therapy at our institute in April 2015. We compared the outcome of the patients during the period before (group 1: standard medical treatment including intravenous [IV] tPA) and after (group 2: standard medical treatment including IV tPA with or without EVT) the introduction of EVT.

Results: In the group 1, all 87 patients (median age, 81 years; NIHSS, 20; ASPECTS, 8; onset to door, 237min; IV tPA 24%) were treated medically (Table 1). In the group 2, among 123 patients (age, 82 years; NIHSS, 20; ASPECTS, 8; onset to door, 149min; IV tPA 16%), 47 patients were treated medically, and the remaining 76 patients underwent EVT (TICI 2b or 3, 84%). Although the median transfer distance increased (23km in the group 1 vs 30km in the group 2, p=0.028), the median time from call to admission was equivalent (42min vs 43min, p=0.93) because of the increase in the proportion of the helicopter transfer (30% vs 41%, p=0.14). The rates of patients who underwent revascularization therapy with IV tPA or EVT (24% vs 66%, p<0.001) and good outcome (mRS 0 to 2) at discharge (11% vs 24%, p=0.021) increased significantly after the introduction of EVT approach.

Conclusions: Our study showed that the introduction of EVT improved the outcome of the AIS therapy with significant increase in the number of patients receiving revascularization therapy. EVT in collaboration with air ambulance might expand the target area for revascularization therapy in a rural broad region.

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.

[Association of Deep Venous Thrombosis with D-dimer Values in Patients with Hemorrhagic Stroke]

Pulmonary embolism(PE)in the early phase of stroke worsens the prognosis. It is necessary to detect deep venous thrombosis(DVT)to avoid PE. We conducted the D-dimer screening in order to detect DVT at an earlier stage. We retrospectively analyzed the clinical data of patients with hemorrhagic stroke who were admitted to the local stroke center, and investigated the complication rates of DVT, PE, D-dimer values, and risk factors of DVT. From October 2012 to August 2014, 261 patients were included. DVT was detected in 46 patients(17.6%)and anticoagulant therapy was started in 5 patients with central DVT. PE did not occur during this observation period. The D-dimer cutoff value for estimating the presence of the DVT was 8.9μg/mL, and the risk factors for DVT were older age, severe neurological disability, prolonged hospital stays, and subarachnoid hemorrhage. D-dimer screening is very useful to make earlier diagnosis and treatment of DVT.

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.

Endovascular Internal Trapping of Ruptured Occipital Artery Pseudoaneurysm Associated with Occipital-Internal Jugular Vein Fistula in Neurofibromatosis Type 1

Spontaneous cervical extradural pseudoaneurysms or arteriovenous fistulas (AVFs) are rare vascular diseases. We report a case of ruptured occipital artery (OA) pseudoaneurysm associated with occipital-internal jugular vein (IJV) fistula in neurofibromatosis type 1. Endovascular internal trapping via the OA was attempted; however, the distal entry of the OA could not be accessed because of the high shunt flow and tortuosity of the OA. The distal part of the OA was obliterated with coil via a transvenous approach through the IJV and pseudoaneurysm. The proximal entry of the OA was obliterated with coil and glue under proximal flow control with a balloon, and the fistula was successfully obliterated without placement of coils in the pseudoaneurysm. When ordinary internal trapping via a transarterial approach is not possible, the transvenous approach should be considered as an alternative for AVF associated with an aneurysmal component.

Abstract WP133: Long-term Outcomes of Carotid Endarterectomy and Carotid Artery Stenting: Real-World Status of Single Institute in Japan

Introduction: We investigated long-term outcomes of carotid endarterectomy (CEA) and carotid artery stenting (CAS) in our hospital to assess the outcomes of real-world practice in single institute of Japan.

Methods: Between August 2006 and July 2014, 236 consecutive carotid revascularizations with either CEA or CAS were performed in our institute. The initial treatment was regarded as the starting point in the cases of the patients who received treatment by bilateral carotid artery stenosis or retreatment. We assessed the long-term outcomes with survival analyses.

Results: A total of 210 patients (CEA 128, CAS 82), including 94 symptomatic patients, were enrolled in the current study with mean follow-up period of 45.8 months. The periprocedural stroke/death/myocardial infarction (MI) rate was 3.1% for CEA and 4.9% for CAS groups (p=0.71). Estimates of the 4-year event-free rate from the primary end point (the composite of any stroke, death, or MI within 30 days and any ipsilateral stroke thereafter) using competing risk analysis were 3.1% for CEA and 8.6% for CAS (P=0.041). Kaplan-Meier estimates of the 4-year event-free rate from the secondary end point (the composite of any stroke, death, or MI within 30 days and any stroke or death thereafter) were 12.8% for CEA and 20.1% for CAS (P=0.051). Age (Hazard ratio [HR], 1.14/year [95%CI, 1.03-1.26]; p = 0.012) and CAS (HR, 3.5 [95%CI, 1.05-11.5]; p = 0.04 ) were significant predictors for the primary end point in multivariate analysis. For the secondary end point, age (HR, 2.1/10year [95%CI, 1.27-3.47]; p = 0.004) and CAS (HR, 2.0 [95%CI, 1.04-3.83], p = 0.037) were significant predictors. The inclusion of higher risk patients in the CAS group may have been the reason for CAS being a risk factor.

Conclusion: The current study on real-world practices demonstrated perioperative and long-term outcomes that were comparable to previous major studies of large numbers of patients.

Long-Term Outcomes of Carotid Endarterectomy and Carotid Artery Stenting for Carotid Artery Stenosis: Real-World Status in Japan

BACKGROUND AND PURPOSE

We investigated long-term outcomes of carotid endarterectomy (CEA) and carotid artery stenting (CAS) in our institute to evaluate the outcomes of real-world practice in Japan.

METHODS

Between August 2006 and July 2013, 203 consecutive carotid revascularizations with either CEA or CAS were performed in our institute. The initial treatment was regarded as the starting point in the cases of the patients who received treatment by bilateral carotid artery stenosis or retreatment. We assessed the long-term outcomes with survival analyses.

RESULTS

A total of 182 patients (CEA 111, CAS 71), including 86 symptomatic patients, were included in the current study with a mean follow-up period of 42.9 months. The periprocedural stroke/death/myocardial infarction (MI) rate was 3.6% for CEA and 5.6% for CAS groups (P = .71). Estimates of the 4-year event-free rate from the primary end point (the composite of any stroke, death, or MI within 30 days, and any ipsilateral stroke thereafter) using competing risk analysis were 3.6% for CEA and 7.1% for CAS (P = .156). Kaplan-Meier estimates of the 4-year event-free rate from the secondary end point (the composite of any stroke, death, or MI within 30 days, and any stroke or death thereafter) were 13.8% for CEA and 19.1% for CAS (P = .072). Age was the only significant predictor for the primary end point. Both age and CAS were significant predictors for the secondary end point.

CONCLUSIONS

The current study on real-world practices demonstrated perioperative and long-term outcomes that were comparable to previous major studies of large numbers of patients.

Compensatory glutamine metabolism promotes glioblastoma resistance to mTOR inhibitor treatment

The mechanistic target of rapamycin (mTOR) is hyperactivated in many types of cancer, rendering it a compelling drug target; however, the impact of mTOR inhibition on metabolic reprogramming in cancer is incompletely understood. Here, by integrating metabolic and functional studies in glioblastoma multiforme (GBM) cell lines, preclinical models, and clinical samples, we demonstrate that the compensatory upregulation of glutamine metabolism promotes resistance to mTOR kinase inhibitors. Metabolomic studies in GBM cells revealed that glutaminase (GLS) and glutamate levels are elevated following mTOR kinase inhibitor treatment. Moreover, these mTOR inhibitor-dependent metabolic alterations were confirmed in a GBM xenograft model. Expression of GLS following mTOR inhibitor treatment promoted GBM survival in an α-ketoglutarate-dependent (αKG-dependent) manner. Combined genetic and/or pharmacological inhibition of mTOR kinase and GLS resulted in massive synergistic tumor cell death and growth inhibition in tumor-bearing mice. These results highlight a critical role for compensatory glutamine metabolism in promoting mTOR inhibitor resistance and suggest that rational combination therapy has the potential to suppress resistance.

Regiocontrolled deprotonative-zincation of bromopyridines using aminozincates

Regiochemistry in the deprotonation of bromopyridines was found to be greatly influenced by the choice of metal amide base, and DA-zincate and TMP-zincate turned out to be excellent complementary practical agents for regioselective metalation of bromopyridines.

Neuronal and glial characteristics of central neurocytoma: electron microscopical analysis of two cases

We have identified two central neurocytomas which contained cells co-expressing glial fibrillary acidic protein and synaptophysin defined by double-label immunostaining. Dual-positive cells were mostly polygonal in shape and with a morphological appearance similar to that of reactive astrocytes. This distinct morphology could be used to distinguish cells expressing glial fibrillary acidic protein from cells with round and clear cytoplasm which did not express glial fibrillary acidic protein and which composed the majority of the tumor. Samples containing polygonal cells were selected for electron microscopy from toluidine blue-stained semithin sections. Ultrastructural findings were similar in both neurocytomas, with both being composed predominantly of round cells with clear cytoplasm corresponding to the clear cells identified by light microscopy. Dense-core vesicles and clear vesicles were frequently observed in the cell processes. Apart from these clear cells, polygonal cells with electron-dense cytoplasm were noted. Paralleling the result of double immunostaining, these polygonal cells contained both dense-core vesicles and intermediate, presumably glial filaments. Microtubules and lipofuscin granules were also observed. These results suggest that cells expressing glial fibrillary acidic protein in central neurocytoma include tumor cells with both neuronal and glial characteristics.

[Effective measures against side effects by increasing ACNU dose for malignant glioma: effects on digestive organs]

Loading therapy consisting of the ACNU regimen was instituted as postoperative anticancer chemotherapy for malignant gliomas. The efficacy rate of the regimen was 25% at a dose of 3 mg/kg. A high incidence of hematological changes, such as leukopenia (neutropenia) and thrombocytopenia, were observed after chemotherapy. The former could be prevented by the administration of G-CSF, but platelet infusions were necessary in some patients for amelioration of thrombocytopenia. Gastroenterological symptoms, such as nausea and vomiting, were also frequently noted. Granisetron (Kytril), which is a recently developed selective competitive inhibitor of the 5-HT3 receptor, was used for the treatment of these adverse effects, and was found to be clinically effective.

[Detection of chromosomal numerical aberration in glioma by FISH (fluorescence in situ hybridization)]

FISH method with chromosome specific DNA probe to interphase nuclei has been useful for the analysis of chromosomal numerical aberration in human brain tumor. We applied the FISH method to 9 gliomas and one glioma cell line (KMU-100) with 4 kinds of chromosomes of number 7, 9, 10 and 17. The predominant specific aberration in glioma were revealed the increased signal numbers of chromosome 7&17 and the decreased signal numbers of chromosome 9&10. The inactivation of tumor suppressor genes and the activation of oncogenes have been suggested as the principal mechanism of tumorigenesis in human cancer. The definite oncogenes have not still been identified on chromosome 7&17 and tumor suppressor genes on chromosome 9&10. We discussed the mechanism of tumorigenesis with one or more oncogenes on chromosome 7&17 and of one or more tumor suppressor genes on chromosome 9&10 in glioma.

Perfusion preservation of cadaver rat pancreas: II. Culture after perfusion and successful transplantation

We designed a new process for culturing pancreatic islets and applied this method to cultures of rat pancreatic islets which had degenerated during preservation by the perfusion-method for 6 hours under the condition of hypothermia and oxygenation. The objective was to determine the extent of the original function. Transplantation of these so-treated islets was also attempted. When pancreatic islets isolated from the pancreas after 6-hour-perfusion were cultured, morphological restoration was apparent within the first 3-4 days. Insulin contents of the culture media renewed every 3 days, ranged from 851 to 1,134 microU/ml/two islets during culture period of 21 days. In the glucose-loading test, insulin secretion of the islets was the same as that of islets in the control experiments. Transplantation of these islets into the portal vein of streptozotocin-induced diabetic rats resulted in a good recovery from the diabetic state.