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Featured researches published by Ayumu Eto.


Journal of Stroke & Cerebrovascular Diseases | 2015

The Safety and Efficacy of Triple Antiplatelet Therapy after Intracranial Stent-Assisted Coil Embolization.

Yoshihisa Matsumoto; Minoru Iko; Masanori Tsutsumi; Takahumi Mitsutake; Ayumu Eto; Kouhei Nii; Kanji Nakai; Hiromichi Oishi; Hiroshi Aikawa; Kiyoshi Kazekawa

BACKGROUND Stent-assisted coil embolization is effective for intracranial aneurysms, especially for wide-necked aneurysms; however, the optimal antiplatelet regimens for postoperative ischemic events have not yet been established. We aimed at determining the efficacy and safety of a triple antiplatelet therapy regimen after intracranial stent-assisted coil embolization. METHODS We retrospectively evaluated patients who underwent stent-assisted coil embolization for unruptured intracranial aneurysms or during the chronic phase of a ruptured intracranial aneurysm (≥ 4 weeks after subarachnoid hemorrhage onset). We recorded the incidence of ischemic and bleeding events 140 days postoperatively. RESULTS We assessed 79 cases in patients who received either dual (n = 51) or triple (n = 28) antiplatelet therapy. The duration of triple antiplatelet therapy was 49 ± 29 days. Seven patients in the dual group experienced postoperative ischemic events. Compared to the dual group, the triple group had a similar incidence of postoperative bleeding events but a significantly lower incidence of postoperative ischemic events (P < .05). CONCLUSIONS Triple antiplatelet therapy had a significantly lower incidence of postoperative ischemic events and a similar incidence of postoperative bleeding events 140 days postoperatively.


Journal of Stroke & Cerebrovascular Diseases | 2014

Onset Time of Ischemic Events and Antiplatelet Therapy after Intracranial Stent-assisted Coil Embolization

Yoshihisa Matsumoto; Kanji Nakai; Masanori Tsutsumi; Minoru Iko; Kouhei Nii; Sumito Narita; Ayumu Eto; Takahumi Mitsutake; Hiroshi Aikawa; Kiyoshi Kazekawa

BACKGROUND Stent-assisted coil embolization is effective for intracranial aneurysms, especially wide-necked aneurysms; however, the optimal antiplatelet regimens for ischemic events that develop after coil embolization have not yet been established. We aimed to determine the onset time of such postoperative ischemic events and the relationship between these events and antiplatelet therapy. METHODS We performed coil embolization using a vascular reconstruction stent for 43 cases of intracranial aneurysms and evaluated the incidence of postoperative ischemic events in these cases. RESULTS Nine patients showed postoperative ischemic events during the follow-up period (13 ± 7 months). Two patients developed cerebral infarction within 24 hours. Five patients developed transient ischemic attack within 40 days while they were receiving dual antiplatelet therapy. In addition, 1 patient showed cerebral infarction 143 days postoperatively during single antiplatelet therapy, and a case of transient visual disturbance was reported 191 days postoperatively (49 days after antiplatelet therapy had been discontinued). We increased the number of antiplatelet agents in 4 of these patients. The other 5 patients were under strict observation with dual antiplatelet therapy. All these patients were shifted to single antiplatelet therapy 3-13 months postoperatively. No recurrence of ischemic events was noted. CONCLUSIONS Postoperative ischemic events are most likely to occur within 40 days postoperatively. For patients with postoperative ischemic events, additional ischemic events can be prevented by increasing the number of antiplatelet agents; subsequently, they can be shifted to single antiplatelet therapy after the risk of recurrence has decreased.


SpringerPlus | 2014

Treatment outcomes of carotid artery stenting with two types of distal protection filter device

Minoru Iko; Hiroshi Aikawa; Yoshinori Go; Kanji Nakai; Masanori Tsutsumi; Iwae Yu; Taichiro Mizokami; Kimiya Sakamoto; Ritsuro Inoue; Takafumi Mitsutake; Ayumu Eto; Hayatsura Hanada; Kiyoshi Kazekawa

PurposePreventing cerebral embolism from debris produced during carotid artery stenting (CAS) is important. This study compared the treatment outcomes of CAS using two types of filter-based embolic protection devices currently in use in Japan.Materials and methodsWe assessed 121 consecutive cases of CAS performed with FilterWire EZ™ between July 2010 and November 2012 and 37 consecutive cases of CAS performed with the Spider FX™ between November 2012 and June 2013. A Carotid Wallstent™ was used in all cases. The incidence of positive lesions on diffusion-weighted magnetic resonance imaging (DWI) and stroke were compared between the groups.ResultsPostoperative DWI-positive lesions were observed in 38 (31.4%) and 14 (37.8%) patients in the FilterWire and Spider groups, respectively. In the FilterWire group, complications were transient ischemic attacks in 3 (2.5%) patients, cerebral infarction in 2 (1.7%) patients (1 patient each with minor and major stroke), and cerebral hemorrhage due to hyperperfusion syndrome in 1 (0.8%) patient. In the Spider group, except for cerebral infarction (minor stroke) in 1 (2.7%) patient, no complications were observed. No significant differences were observed in the incidence of complications between the groups.ConclusionFilterWire EZ and Spider FX are comparable in terms of treatment outcome.


Journal of Stroke & Cerebrovascular Diseases | 2014

Nε-(Carboxymethyl)lysine in Debris from Carotid Artery Stenting: Multiple versus Nonmultiple Postoperative Lesions

Ritsurou Inoue; Noriyuki Sakata; Kanji Nakai; Hiroshi Aikawa; Masanori Tsutsumi; Kouhei Nii; Minoru Iko; Kimiya Sakamoto; Ayumu Eto; Ryoji Nagai; Kiyoshi Kazekawa

BACKGROUND No predictor of postoperative ischemic events has been identified in patients undergoing carotid artery stenting (CAS). We aimed to determine whether N(ε)-(carboxymethyl)lysine (CML) in debris trapped by an embolic protection filter device is a predictor of postoperative ischemic events. METHODS We enrolled 27 patients (73.4 ± 7.2 years; 22 male, 5 female) who underwent CAS for carotid artery stenosis. Diffusion-weighted magnetic resonance imaging was performed before and after the procedure. Protein samples were extracted from the debris. CML and myeloperoxidase were examined by solid phase enzyme-linked immunosorbent assay and Western blot analysis. RESULTS Seventeen patients had 0 or 1 new lesion (nonmultiple lesions) postoperatively, whereas 10 patients had 2 or more new lesions postoperatively (multiple lesions). The CML concentration of the protein sample was significantly higher in patients with multiple lesions than in those with nonmultiple lesions (6.26 ± 2.77 ng/mg protein and 3.36 ± 1.57 ng/mg protein, respectively; P = .010). Statin therapy for dyslipidemia was associated with a lower incidence of multiple lesions and a lower concentration of CML in the protein sample (P = .004 and P = .02, respectively). Receiver operating characteristic analysis showed that the area under the curve for CML was significantly greater than .5 (.877; 95% confidence interval, .742-1.00). CONCLUSIONS CML derived from debris may distinguish between patients with postoperative multiple ischemic lesions and those with postoperative nonmultiple lesions who undergo CAS.


Neurologia Medico-chirurgica | 2016

Comparison of Flow Impairment during Carotid Artery Stenting Using Two Types of Eccentric Filter Embolic Protection Devices

Kouhei Nii; Masanori Tsutsumi; Hitoshi Maeda; Hiroshi Aikawa; Ritsuro Inoue; Ayumu Eto; Kimiya Sakamoto; Takafumi Mitsutake; Hayatsura Hanada; Kiyoshi Kazekawa

We investigated the angiographic findings and the clinical outcomes after carotid artery stenting (CAS) using two different, eccentric filter embolic protection devices (EPDs). Between July 2010 and August 2015, 175 CAS procedures were performed using a self-expandable closed-cell stent and a simple eccentric filter EPD (FilterWire EZ in 86 and Spider FX in 89 procedures). The angiographic findings (i.e., flow impairment and vasospasm) at the level of EPDs, neurologic events, and post-operative imaging results were compared between the FilterWire EZ and the Spider FX groups. The CAS was angiographically successful in all 175 procedures. However, the angiographs were obtained immediately after CAS-detected flow impairment in the distal internal carotid artery (ICA) in 11 (6.3%) and ICA spasms at the level of the EPD in 40 cases (22.9%). The incidence of these complications was higher with FilterWire EZ than Spider FX (ICA flow impairment of 10.5% vs. 2.2%, P = 0.03; vasospasm 30.2% vs. 15.7%, P = 0.03). There were nine neurologic events (5.1%); five patients were presented with transient ischemic attacks, three had minor strokes, and one had a major stroke. New MRI lesions were seen in 25 (29.1%) FilterWire-group and in 36 (40.4%) Spider-group patients. The neurologic events and new MRI lesions were not associated with the type of EPD used. Although the ICA flow impairment may result in neurologic events, there was no significant association between the FilterWire EZ and the Spider FX CAS with respect to the incidence of neurologic events by the prompt treatment such as catheter aspiration.


Journal of Stroke & Cerebrovascular Diseases | 2016

Relationship between the Carotid Plaque T1 Relaxation Time and the Plaque-to-Muscle Signal Intensity Ratio on Black-Blood Magnetic Resonance Imaging Scans

Ayumu Eto; Yoshimasa Kinoshita; Yoshihisa Matsumoto; Fumiaki Kiyomi; Minoru Iko; Kouhei Nii; Masanori Tsutsumi; Kimiya Sakamoto; Hiroshi Aikawa; Kiyoshi Kazekawa

BACKGROUND Black-blood magnetic resonance imaging (BB-MRI) is useful for the characterization and assessment of carotid artery plaques. The plaque-to-muscle signal intensity (SI) ratio (plaque/muscle ratio [PMR]) is used widely to evaluate plaques. However, the correlation between the PMR and the T1 relaxation time needs to be determined. We measured the T1 relaxation time of carotid plaques using T1 mapping and compared the results with the PMR on BB-MRI scans. METHODS Between April 2014 and July 2015, 20 patients with carotid artery stenosis were treated by carotid artery stenting. All patients underwent preoperative magnetic resonance plaque imaging. The ratio of the plaque SI to the sternocleidomastoid muscle was calculated on T1-weighted BB-MRI scans. T1 mapping was performed in the region where the vessel was narrowest using the inversion recovery technique. The T1 relaxation time was recorded to determine whether there was a correlation with the PMR. RESULTS The plaque T1 value was 577.3 ± 143.2 milliseconds; the PMR value obtained on BB-MRI scans was 1.23 ± .27. There was a statistically significant decrease in the T1 value as the PMR increased (P < .0001). CONCLUSIONS As the T1 relaxation time was well correlated with the PMR on BB-MRI scans, the evaluation of vulnerable plaques using the PMR was reliable and convenient.


Neurology and Clinical Neuroscience | 2017

Cerebellopontine angle meningioma diagnosed based on symptoms of trigeminal neuralgia in late pregnancy and showing spontaneous reduction in the early postpartum period: A case report

Yusuke Morinaga; Haruaki Yamamoto; Misato Kawaguchi; Junya Asato; Hayatsura Hanada; Ayumu Eto; Takafumi Mitsutake; Fumihiro Hiraoka; Ritsurou Inoue; Kimiya Sakamoto; Minoru Iko; Kouhei Nii; Masanori Tsutsumi; Hiroshi Aikawa; Kiyoshi Kazekawa

We describe a case of cerebellopontine angle meningioma, diagnosed by the initial symptoms of trigeminal neuralgia in late pregnancy, that showed spontaneous tumor volume reduction in the puerperal period. A 28‐year‐old woman developed left facial pain at 30 weeks of pregnancy. Magnetic resonance imaging showed a left cerebellopontine angle tumor. She decided to undergo gamma knife treatment at her local hospital. Fifty‐five days postpartum, magnetic resonance imaging was repeated to plan for this treatment. Gadolinium‐enhanced T1‐weighted imaging showed that the tumor had decreased, with no mass effect. The tumor was considered a low‐grade meningioma present before pregnancy, which grew as a result of hypervascular changes or hormone‐induced cellular proliferation in late pregnancy, and subsequently decreased in volume because of blood flow normalization or hormone normalization. The differential diagnosis and treatment of cerebellopontine meningioma during puerperium require careful observation, as the tumor can spontaneously decrease in size despite being symptomatic.


Neurologia Medico-chirurgica | 2017

Usefulness of Consciousness Sedation with Dexmedetomidine and Pentazocine during Endovascular Treatment for Acute Stroke

Kouhei Nii; Hayatsura Hanada; Fumihiro Hiraoka; Ayumu Eto; Takafumi Mitsutake; Masanori Tsutsumi

We investigated the safety and efficacy of consciousness sedation with dexmedetomidine (DEX) during the endovascular treatment of patients with acute cerebral infarction. Between April 2014 and November 2016, 38 stroke patients underwent endovascular thrombectomy (EVT) under local anesthesia and DEX consciousness sedation. The continuous intravenous administration of low-dose DEX (0.3–0.4 μg/kg/h) was started before entering the operating room. Patients not completely immobilized received an iv bolus of pentazocine (PTZ) and/or DEX (0.5–0.6 μg/kg/h). EVT was performed using a stent retriever and/or direct thrombo-aspiration. DEX sedation was stopped as soon as the operation was finished. A stent retriever was used in 8 (21.1%), direct thrombo-aspiration in 10 (26.3%), a stent retriever plus thrombo-aspiration in 14 (36.8%), and other devices in 6 patients (15.8%). Reperfusion exceeding 50% (thrombolysis in cerebral infarction >2b) was obtained in 30 patients (78.9%). DEX sedation alone immobilized 24 patients (63.2%), 14 (36.8%) required the additional injection of DEX or PTZ when EVT devices were navigated to the lesion. The administration of DEX and PTZ elicited no significant respiratory depression or cardiac dysfunction interfering with the procedures. Consciousness sedation by DEX was effective during the endovascular treatment of acute stroke patients. Under DEX sedation and the injection of PTZ, EVT was possible without significantly changing the patients’ vital signs.


Journal of Stroke & Cerebrovascular Diseases | 2017

Nε-(carboxymethyl)lysine Concentration in Debris from Carotid Artery Stenting Correlates Independently with Signal Intensity on T1-Weighted Black-Blood Magnetic Resonance Images

Ayumu Eto; Noriyuki Sakata; Ryoji Nagai; Jun-ichi Shirakawa; Ritsurou Inoue; Fumiaki Kiyomi; Kouhei Nii; Hiroshi Aikawa; Minoru Iko; Masanori Tsutsumi; Kimiya Sakamoto; Fumihiro Hiraoka; Takahumi Mitsutake; Hayatsura Hanada; Kiyoshi Kazekawa

BACKGROUND AND PURPOSE Because magnetic resonance imaging (MRI) focuses on the morphological characteristics of carotid artery plaques, its diagnostic value with respect to plaque vulnerability is limited. We examined the correlation between Nε-(carboxymethyl)lysine (CML), a main chemical structure of advanced glycation end-products, and the vulnerability of plaques visualized on MRI scans. MATERIALS AND METHODS We enrolled 43 patients who had undergone carotid artery stenting (CAS) for carotid artery stenosis; all underwent MRI studies, including black-blood MRI and diffusion-weighted imaging (DWI). The signal intensity ratio (SIR) of plaques to adjacent sternocleidomastoid muscle (P/M) on T1- and T2-weighted images (T1WI, T2WI) was calculated. Protein samples were extracted from debris trapped by a filter device. The concentrations of CML and myeloperoxidase (MPO) were measured by solid-phase enzyme-linked immunosorbent assay. RESULTS The patients were classified into 2 groups based on their SIR-P/M on T1WI and T2WI scans. We observed a higher incidence of post-CAS DWI lesions in patients with a higher than a lower SIR-P/M on T1WI; the CML and MPO concentrations in their CAS debris were also higher. No such differences were seen in patients with a higher or lower SIR-P/M on T2WI scans. The concentration of CML in CAS debris correlated independently with the SIR-P/M on T1WI of the carotid plaques, and was related to the concentration of MPO in CAS debris. CONCLUSIONS Our findings suggest CML as a candidate molecular imaging probe for the identification of vulnerable plaques.


Journal of Stroke & Cerebrovascular Diseases | 2015

A Manual Carotid Compression Technique to Overcome Difficult Filter Protection Device Retrieval during Carotid Artery Stenting

Kouhei Nii; Kanji Nakai; Masanori Tsutsumi; Hiroshi Aikawa; Minoru Iko; Kimiya Sakamoto; Takafumi Mitsutake; Ayumu Eto; Hayatsura Hanada; Kiyoshi Kazekawa

BACKGROUND We investigated the incidence of embolic protection device retrieval difficulties at carotid artery stenting (CAS) with a closed-cell stent and demonstrated the usefulness of a manual carotid compression assist technique. METHODS Between July 2010 and October 2013, we performed 156 CAS procedures using self-expandable closed-cell stents. All procedures were performed with the aid of a filter design embolic protection device. We used FilterWire EZ in 118 procedures and SpiderFX in 38 procedures. The embolic protection device was usually retrieved by the accessory retrieval sheath after CAS. We applied a manual carotid compression technique when it was difficult to navigate the retrieval sheath through the deployed stent. We compared clinical outcomes in patients where simple retrieval was possible with patients where the manual carotid compression assisted technique was used for retrieval. RESULTS Among the 156 CAS procedures, we encountered 12 (7.7%) where embolic protection device retrieval was hampered at the proximal stent terminus. Our manual carotid compression technique overcame this difficulty without eliciting neurologic events, artery dissection, or stent deformity. CONCLUSIONS In patients undergoing closed-cell stent placement, embolic protection device retrieval difficulties may be encountered at the proximal stent terminus. Manual carotid compression assisted retrieval is an easy, readily available solution to overcome these difficulties.

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