Honors & Awards

  • Uehara memorial foundation research fellowship, Uehara memorial foundation (2019-2020)
  • Kusano Award, Japan Heart Foundation (03/2019)
  • Best poster award, Japanese Society of Cerebral Blood Flow and Metabolism (11/2014)

Professional Education

  • Doctor of Philosophy, Nagasaki University (2017)
  • Doctor of Medicine, Nagasaki University (2007)
  • PhD, Nagasaki University (2017)
  • MD, Nagasaki University (2007)

Stanford Advisors

All Publications

  • Surgical Venous Drainage Disconnection from Cavernous Sinus Dural Arteriovenous Fistula and Ruptured Varix WORLD NEUROSURGERY Iki, Y., Morofuji, Y., Somagawa, C., Yamaguchi, S., Hamabe, J., Horie, N., Izumo, T., Suyama, K., Matsuo, T. 2020; 137: 18–23


    Cavernous sinus dural arteriovenous fistulas (CS dAVFs) occasionally behave aggressively (e.g., intracranial hemorrhage, venous infarction, seizures) depending on the drainage flow and presence of a collateral route of cortical or basal cerebral venous drainage. When a CS dAVF with aggressive behavior is encountered, a radical cure is required to avoid catastrophic deficits. However, conventional transvenous cavernous sinus (CS) embolization via the inferior petrosal sinus does not always achieve shunt obliteration. We herein report a case of surgical venous drainage disconnection in an 83-year-old woman with a CS dAVF.The patient presented with coma and anisocoria due to intracranial hemorrhage. Because of the patient's critical condition, we had no choice but to perform emergency decompressive craniectomy and hematoma evacuation without detailed preoperative hemodynamic information obtained by digital subtraction angiography. Postoperative digital subtraction angiography showed a CS dAVF with retrograde venous drainage of the deep middle cerebral vein (DMCV) and varix formation in the affected DMCV, causing hemorrhagic episodes. Five days after admission, the patient's neurologic state worsened because of rebleeding from the varix, which had increased in size. The percutaneous transvenous approach failed because of compartmentalization within the CS. Open surgery was performed; the deep vasculature was exposed by the transsylvian approach, and the arterialized DMCV was permanently clipped at its proximal segment with disconnection from the venous varix and fistulous point. Shunt obliteration was successfully achieved.Surgical venous drainage disconnection from the fistulous point may be an alternative radical therapy for CS dAVFs with aggressive behaviors.

    View details for DOI 10.1016/j.wneu.2020.01.058

    View details for Web of Science ID 000532726200003

    View details for PubMedID 31954912

  • Characteristics of aneurysmal subarachnoid hemorrhage associated with rheumatic disease. Neurosurgical review Yamaguchi, S., Horie, N., Sato, S., Kaminogo, M., Morofuji, Y., Izumo, T., Anda, T., Suyama, K., Matsuo, T. 2020


    Spontaneous subarachnoid hemorrhage (SAH) occurs due to intracranial aneurysm rupture in most cases. Rheumatic disease may cause vessel wall inflammation, which can increase the risk of rupture. However, the characteristics of SAH with rheumatic disease are unknown. This study aimed to evaluate SAH features in patients with rheumatic disease. We retrospectively analyzed clinical data of 5066 patients from the Nagasaki SAH Registry Study who had been diagnosed with aneurysmal SAH between 2001 and 2018. We evaluated the SAH characteristics in patients with rheumatic disease using multivariable logistic regression analysis. In total, 102 patients (2.0%, 11 men and 91 women, median age 69.0 [57.0-75.5]) had rheumatic disease. In these patients, univariate logistic regression analysis showed that sex, hypertension, family history of SAH, smoking history, World Federation of Neurosurgical Societies grade on admission, aneurysm size, multiple aneurysms, treatment, and symptomatic spasms were associated with SAH. Multivariable logistic regression analysis showed that characteristics independently associated with SAH in rheumatic disease were female sex (odds ratio [OR] 3.38; 95% confidence interval [CI] 1.81-6.93, P < 0.001), hypertension (OR 0.60; 95% CI 0.40-0.90, P = 0.012), family history of SAH (OR 0.18; 95% CI 0.01-0.80, P = 0.020), small ruptured aneurysms (OR 1.50; 95% CI 1.02-2.24, P = 0.048), and multiple aneurysms (OR 1.69; 95% CI 1.09-2.58, P = 0.021) in comparison with SAH without rheumatic disease. In conclusion, SAH in patients with rheumatic disease was characterized by small multiple aneurysms, regardless of the low incidence of hypertension and family history of SAH.

    View details for DOI 10.1007/s10143-020-01435-8

    View details for PubMedID 33175266

  • Hypointensity of draining veins on susceptibility-weighted magnetic resonance images might indicate normal venous flow and a lower risk of intracerebral hemorrhage in patients with intracranial arteriovenous shunt(s) Journal of Clinical Neuroscience Yamaguchi, S., Hamabe, J., Horie, N., Iki, Y., Sadakata, E., Hiu, T., Yagi, N., Suyama, K. 2020; 80: 250-256
  • A Case of Cerebral Hyperperfusion Showing Unique Characteristics on Susceptibility-weighted MR Imaging after Carotid Endarterectomy. NMC case report journal Yamaguchi, S., Yoshimura, S., Horikawa, S., Suyama, K., Tokunaga, Y. 2020; 7 (4): 151–55


    Cerebral hyperperfusion syndrome (CHS) is a potentially devastating complication of carotid endarterectomy (CEA). Early detection and treatment of hyperperfusion are important before the condition develops into CHS. We herein present a case involving a 65-year-old female with severe right internal carotid artery (ICA) stenosis, who experienced hyperperfusion after right CEA. During the postoperative course, changes in the resting cerebral blood flow (rCBF) were evaluated using single-photon emission computed tomography (SPECT), and were found to correlate with the changes in the signal intensity of cortical arteries, cortical veins, and perilateral ventricular veins of the right middle cerebral artery (MCA) territory on susceptibility-weighted imaging (SWI). SWI showed a prominent hyperintensity of cortical arteries in the right MCA territory at postoperative day 1 (POD1), but the hyperintensity gradually decreased over time and became indistinct by POD48. As for cortical veins and perilateral ventricular veins, SWI showed an increased signal intensity of these veins during the peak of rCBF on POD1, but later, the signal intensity decreased as rCBF decreased on POD5. The signal intensity of cortical veins and perilateral ventricular veins finally returned to normal on POD9. Those SWI findings could be related to an impairment of cerebral autoregulation and the resulting hyperperfusion. SWI could be potentially useful as an additional tool in the evaluation of hyperperfusion.

    View details for DOI 10.2176/nmccrj.cr.2019-0250

    View details for PubMedID 33062560

    View details for PubMedCentralID PMC7538453

  • Rare Case of Floating Intimal Flap Associated with Atheromatous Carotid Plaque WORLD NEUROSURGERY Yamaguchi, S., Hamabe, J., Yamashita, A., Irie, J., Yagi, N., Suyama, K. 2019; 122: 98–101


    A mobile carotid plaque can be detected by duplex ultrasonography and is a high-risk factor for embolic stroke.We herein present a case involving an 80-year-old man with an asymptomatic carotid floating flap diagnosed by duplex ultrasonography and treated with carotid endarterectomy. Intraoperatively, an ulceration was found immediately proximal to the neck of the floating flap, and the shape and size of the ulceration were quite similar to those of the floating flap. In a histopathologic examination of the specimen resected by carotid endarterectomy, the plaque lacked the internal elastic lamina (IEL) at the ulceration, calcification was observed in the plaque and medial layer at the ulceration, and the floating flap consisted of the IEL accompanied by calcification, fibrin, and foamy cells.Progression of the atheroma and Mönckeberg sclerosis might have affected disruption of the IEL, causing the IEL to finally peel off. A floating intimal flap accompanied by an atheroma without intraplaque hemorrhage is a rare cause of mobile plaque formation. This type of mobile plaque might not be dissolved by medical treatment alone. In such cases, surgical treatment is a suitable therapeutic choice to prevent stroke.

    View details for DOI 10.1016/j.wneu.2018.10.139

    View details for Web of Science ID 000457328100220

    View details for PubMedID 30391611

  • Iatrogenic Removal of the Intima in the Middle Cerebral Artery by a Stent Retriever: A Report of Two Cases WORLD NEUROSURGERY Yamaguchi, S., Hamabe, J., Horie, N., Yamashita, A., Irie, J., Tokuda, Y., Mutsukura, K., Yagi, N., Suyama, K. 2018; 118: 203–8


    Mechanical thrombectomy improves functional outcomes in patients with acute ischemic stroke. However, stent retrievers have the risk of vascular damage.We present 2 cases of patients with acute internal carotid artery occlusion who experienced removal of the intima by a stent retriever. In both patients, a 6 × 30-mm Solitaire stent was fully deployed from the M2 portion and slowly withdrawn. White membranes were retrieved outside the strut in both patients. Histopathologic examination showed that one membrane consisted of thickened intima and internal elastic lamina and the other consisted of calcified intima and internal elastic lamina. One patient who suffered embolic stroke experienced recurrent infarction within 24 hours after operation, and the damaged vessel was occluded on magnetic resonance angiography 21 days after stroke. In another patient with carotid artery dissection, the damaged vessel showed asymptomatic stenosis on magnetic resonance angiography 90 days after stroke. Arteries with both atherosclerosis and vessel dissection may be vulnerable to high radial expansion force.Full deployment of a relatively large-sized stent into a vulnerable vessel may cause vessel dissection after removal of the intima. Appropriate material selection and treatment strategy while considering stroke etiology and the occlusion site are important to prevent vessel damage.

    View details for DOI 10.1016/j.wneu.2018.07.118

    View details for Web of Science ID 000445032000167

    View details for PubMedID 30048785

  • A Case of Rapid Malignant Brain Swelling Subacutely After Reperfusion Therapy for Internal Carotid Artery Occlusion WORLD NEUROSURGERY Yamaguchi, S., Hamabe, J., Horie, N., Kishikawa, T., Yagi, N., Suyama, K. 2018; 118: 311–15


    Severe complications after reperfusion therapy for acute major vessel occlusion are not well described. We present an extremely rare case of a patient with rapid malignant brain swelling subacutely after acute ischemic stroke.An 84-year-old man underwent reperfusion therapy for acute left internal carotid artery occlusion; complete reperfusion was achieved. Although magnetic resonance imaging on postoperative day 1 revealed a small hemorrhagic infarction and subarachnoid hemorrhage unrelated to a left middle cerebral artery aneurysm in the left frontal lobe, neurologic deficits resolved completely. On postoperative day 5, the patient developed a fever and sudden disorder of consciousness with right hemiparesis. Urosepsis was diagnosed, and computed tomography revealed massive hemorrhagic infarction in the left frontal lobe and diffuse subarachnoid hemorrhage. Emergent hematoma evacuation and clipping were performed. Although the aneurysm was unruptured, brain swelling was severe despite a patent middle cerebral artery. Computed tomography performed immediately postoperatively (within 6 hours after preoperative computed tomography) showed severe left brain swelling with midline shift. The patient died on postoperative day 15.This case has similarities to both second-impact syndrome after head trauma and perfusion breakthrough phenomenon. Initial ischemic damage following reperfusion therapy and damage secondary to sepsis and subarachnoid hemorrhage may have led to rapid malignant brain swelling in this patient. Careful management is important for patients receiving reperfusion therapy.

    View details for DOI 10.1016/j.wneu.2018.07.151

    View details for Web of Science ID 000445032000187

    View details for PubMedID 30055370

  • Age of donor of human mesenchymal stem cells affects structural and functional recovery after cell therapy following ischaemic stroke JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM Yamaguchi, S., Horie, N., Satoh, K., Ishikawa, T., Mori, T., Maeda, H., Fukuda, Y., Ishizaka, S., Hiu, T., Morofuji, Y., Izumo, T., Nishida, N., Matsuo, T. 2018; 38 (7): 1199–1212


    Cell transplantation therapy offers great potential to improve impairments after stroke. However, the importance of donor age on therapeutic efficacy is unclear. We investigated the regenerative capacity of transplanted cells focusing on donor age (young vs. old) for ischaemic stroke. The quantities of human mesenchymal stem cell (hMSC) secreted brain-derived neurotrophic factor in vitro and of monocyte chemotactic protein-1 at day 7 in vivo were both significantly higher for young hMSC compared with old hMSC. Male Sprague-Dawley rats subjected to transient middle cerebral artery occlusion that received young hMSC (trans-arterially at 24 h after stroke) showed better behavioural recovery with prevention of brain atrophy compared with rats that received old hMSC. Histological analysis of the peri-infarct cortex showed that rats treated with young hMSC had significantly fewer microglia and more vessels covered with pericytes. Interestingly, migration of neural stem/progenitor cells expressing Musashi-1 positively correlated with astrocyte process alignment, which was more pronounced for young hMSC. Aging of hMSC may be a critical factor that affects cell therapy outcomes, and transplantation of young hMSC appears to provide better functional recovery through anti-inflammatory effects, vessel maturation, and neurogenesis potentially by the dominance of trophic factor secretion.

    View details for DOI 10.1177/0271678X17731964

    View details for Web of Science ID 000438582200006

    View details for PubMedID 28914133

    View details for PubMedCentralID PMC6434451

  • Assessment of veins in T2*-weighted MR angiography predicts infarct growth in hyperacute ischemic stroke PLOS ONE Yamaguchi, S., Horie, N., Morikawa, M., Tateishi, Y., Hiu, T., Morofuji, Y., Lzumo, T., Hayashi, K., Matsuo, T. 2018; 13 (4): e0195554


    T2*-weighted magnetic resonance angiography (SWAN) detects hemodynamic insufficiency as hypointense areas in medullary or cortical veins. We therefore investigated whether SWAN can help predict ischemic penumbra-like lesions in patients with acute ischemic stroke (AIS).Magnetic resonance imaging (MRI) records-including SWAN, diffusion-weighted imaging (DWI), and magnetic resonance angiography (MRA)-of consecutive patients with major vessel occlusion within 6 h from AIS onset were analyzed. Acute recanalization was defined as an arterial occlusive lesion score of 2-3. A modified Alberta Stroke Program Early CT Score (mASPECTS) was used to evaluate ischemic areas revealed by SWAN and DWI. SWAN- and DWI-based mASPECTSs were calculated, and correlations between DWI-SWAN mismatches with final infarct lesions or clinical outcomes were evaluated.Among the 35 patients included in this study, we confirmed cardioembolic stroke in 26, atherothrombotic stroke in 4, and unknown stroke etiology in 5. Overall, recanalization was achieved in 23 patients, who showed a higher follow-up DWI-based mASPECTS and lower modified Rankin Scale (mRS) score at 90 days than patients without recanalization. Initial SWAN- and follow-up DWI-based mASPECTSs were significantly higher for atherothrombotic stroke than for cardioembolic stroke. Of 12 patients without recanalization, DWI-SWAN mismatch was significantly correlated with infarct growth. Patients with recanalization showed no such correlation. In the assessment of clinical outcome, follow-up DWI-based mASPECTS and patient's age were significantly correlated with mRS at 90 days after stroke. A multivariate logistic regression analysis revealed that the follow-up DWI-based mASPECTS was independently associated with a favorable outcome 90 days after stroke.For patients with AIS, DWI-SWAN mismatch might show penumbra-like lesions that would predict infarct growth without acute recanalization. Assessment of ischemic lesions from the venous side appears to be useful for considering the etiology and revascularization therapy.

    View details for DOI 10.1371/journal.pone.0195554

    View details for Web of Science ID 000429203800092

    View details for PubMedID 29617449

    View details for PubMedCentralID PMC5884555

  • Rapid Recanalization Using TrevoProVue through a 4.2 Fr Catheter without a Guiding Catheter via Transbrachial Approach: A Case Report. NMC case report journal Yamaguchi, S., Horie, N., Morofuji, Y., Satoh, K., Suyama, K. 2017; 4 (4): 97–99


    Mechanical thrombectomy with a stent retriever has been reported to achieve high rates of successful recanalization, and reduce disability and mortality in patients with acute ischemic stroke (AIS) due to proximal vessel occlusion. However, in a few cases, the treatment is difficult due to artery tortuosity or other factors. The authors present a case of a 94-year-old man presenting with acute right middle cerebral artery occlusion. We attempted to treat using a stent retriever via transfemoral approach, but failed to advance the guiding catheter into the right internal carotid artery due to femoral artery tortuosity and a type III arch. By changing approaches from transfemoral to transbrachial and by using TrevoProVue through a 4.2 Fr Simmons-type catheter without a guiding catheter, we were able to achieve rapid recanalization in only 26 minutes from brachial artery puncture to reperfusion. In conclusion, rapid reperfusion in an AIS patient was successfully achieved by combining a stent retriever with a 4.2 Fr catheter (without a guiding catheter) and a transbrachial approach (as opposed to a transfemoral approach). When the transfemoral approach is not feasible, we recommend consideration of this strategy as an alternative.

    View details for DOI 10.2176/nmccrj.cr.2016-0235

    View details for PubMedID 29018649

    View details for PubMedCentralID PMC5629352

  • Point-by-point parent artery/sinus obliteration using detachable, pushable, 0.035-inch coils ACTA NEUROCHIRURGICA Yamaguchi, S., Horie, N., Hayashi, K., Fukuda, S., Morofuji, Y., Hiu, T., Izumo, T., Morikawa, M., Matsuo, T. 2016; 158 (11): 2089–94


    Parent artery occlusion for intractable aneurysms or sinus packing for dural arteriovenous fistulas (DAVFs) is sometimes difficult and requires many expensive coils to accomplish complete occlusion. To help solve these problems, we reviewed our experience using 0.035-inch coil (0.035 coil; Boston Scientific, San Leandro, CA, USA), which has been used in cardiovascular and abdominal lesions.These 0.035 coils were preferably used in addition to the detachable and fibered coils for patients with intractable aneurysms, traumatic vessel blowout, and DAVF. Our strategy was as follows: (1) detachable coils were deployed first for the ideal anchoring of the coils; (2) small fibered coils were additionally deployed to stabilize the coil mass; (3) 0.035 coils were deployed to complete the occlusion.From January 2012 to December 2013, seven consecutive patients were treated by endovascular embolization with 0.035 coils. Reasons for intervention were parent artery occlusion for carotid blowout (n = 1), internal carotid artery aneurysm (n = 2), traumatic vertebral artery injury (n = 2), vertebral AVF (n = 1), and transverse sinus-sigmoid sinus DAVF (n = 1). In our cases, a mean of 20.1 ± 8.5 coils per vessel were placed, and mean total coil length was 258.4 ± 91.5 cm per vessel. All procedures were safely performed and complete occlusions achieved.From our initial experience and treatment results, we believe endovascular parent artery occlusion or sinus packing with 0.035 coils to be useful in terms of reducing the number and expense of coils and also accomplishing immediate occlusion.

    View details for DOI 10.1007/s00701-016-2946-6

    View details for Web of Science ID 000386362200010

    View details for PubMedID 27586124

  • Follow-up after undersized dilatation of targeted lesions in carotid artery stenting BRITISH JOURNAL OF NEUROSURGERY Murakami, M., Hatano, T., Miyakoshi, A., Arai, D., Yamaguchi, S., Ogino, E., Ohtani, R., Tsukahara, T. 2015; 29 (5): 661–67


    We assessed whether intentional undersized dilatation of targeted lesions during carotid artery stenting (CAS) carried a higher risk of in-stent restenosis (ISR) and correlation to subsequent ischemic stroke in qualifying arteries in the follow-up period.Consecutive patients undergoing CAS between April 2003 and May 2010 were retrospectively reviewed. The use of a filter device as a distal embolic protection device (EPD) was first approved by Japanese governmental health insurance in April 2008; previously, transient balloon occlusion was used off-label. Until March 2008 (Group A), the target diameter of balloon dilatation was 80-100% of the normal vessel diameter just distal to the stenotic lesion. Moderately undersized dilatation (70-80% of the normal vessel diameter) using the distal EPD was adopted in April 2008 (Group B) in an attempt to reduce the amount of released plaque debris.We analyzed 132 CAS procedures (125 patients) in Group A and 53 CAS procedures (52 patients) in Group B. The mean follow-up period was 35.4 months (35.3 months in Group A and 36.0 months in Group B). Eight lesions (4.3%; 7 in Group A and 1 in Group B) developed ISR. None of the patients had symptomatic ISR, and ISR did not increase in Group B (odds ratio, 0.34; 95% confidence interval, 0.04-2.86; p = 0.32).Undersized dilatation of targeted lesions did not increase the risk of developing ISR, and we suggest it as a viable treatment option to prevent ischemic events during CAS.

    View details for DOI 10.3109/02688697.2015.1029430

    View details for Web of Science ID 000366208900010

    View details for PubMedID 25968328

  • Intraoperative Angiography Using Portable Fluoroscopy Unit in the Treatment of Vascular Malformation NEUROLOGIA MEDICO-CHIRURGICA Hayashi, K., Horie, N., Morofuji, Y., Fukuda, S., Yamaguchi, S., Izumo, T. 2015; 55 (6): 505–9


    Intraoperative angiography (IOA) is employed for the treatment of the complicated cases in neurological surgery. The IOA is usually performed with OEC portable digital subtraction angiography (DSA) unit. We are performing IOA with portable fluoroscopy unit with simple DSA function and report its usefulness on neurosurgical treatment. IOA or hybrid treatment with mobile fluoroscopy system was performed for 9 cases [cerebral arteriovenous malformation (AVM), 3; cranial dural arteriovenous fistula (AVF), 2; and spinal AVM/AVF, 4]. Thus, ex vivo analysis was performed comparing image quality of portable fluoroscopy unit and conventional DSA system. Although the resolution of portable fluoroscopy unit is not so high compared to conventional DSA system, the existence of the vascular lesions such as cerebral aneurysm, cerebral AVM, and spinal dural AVF were detected. The operation of portable fluoroscopy unit was simple and no special assistance was required. The complication related to the catheterization or IOA did not occur. IOA with portable fluoroscopy unit was useful for the identification of vascular lesion and has advantage on the cost benefit.

    View details for DOI 10.2176/nmc.oa.2014-0315

    View details for Web of Science ID 000356399400008

    View details for PubMedID 26041625

    View details for PubMedCentralID PMC4628203

  • Intra-Arterial Transplantation of Low-Dose Stem Cells Provides Functional Recovery Without Adverse Effects After Stroke CELLULAR AND MOLECULAR NEUROBIOLOGY Fukuda, Y., Horie, N., Satoh, K., Yamaguchi, S., Morofuji, Y., Hiu, T., Izumo, T., Hayashi, K., Nishida, N., Nagata, I. 2015; 35 (3): 399–406


    Cell transplantation therapy for cerebral infarction has emerged as a promising treatment to reduce brain damage and enhance functional recovery. We previously reported that intra-arterial delivery of bone marrow mesenchymal stem cells (MSCs) enables superselective cell administration to the infarct area and results in significant functional recovery after ischemic stroke in a rat model. However, to reduce the risk of embolism caused by the transplanted cells, an optimal cell number should be determined. At 24 h after middle cerebral artery occlusion and reperfusion, we administered human MSCs (low dose: 1 × 10(4) cells; high dose: 1 × 10(6) cells) and then assessed functional recovery, inflammatory responses, cell distribution, and mortality. Rats treated with high- or low-dose MSCs showed behavioral recovery. At day 8 post-stroke, microglial activation was suppressed significantly, and interleukin (IL)-1β and IL-12p70 were reduced in both groups. Although high-dose MSCs were more widely distributed in the cortex and striatum of rats, the degree of intravascular cell aggregation and mortality was significantly higher in the high-dose group. In conclusion, selective intra-arterial transplantation of low-dose MSCs has anti-inflammatory effects and reduces the adverse effects of embolic complication, resulting in sufficient functional recovery of the affected brain.

    View details for DOI 10.1007/s10571-014-0135-9

    View details for Web of Science ID 000351236400010

    View details for PubMedID 25398358

  • Quadruple coaxial catheter system on transvenous embolization for dural arteriovenous fistula NEUROLOGICAL RESEARCH Hayashi, K., Horie, N., Morofuji, Y., Fukuda, S., Yamaguchi, S., Morikawa, M. 2015; 37 (4): 328–31


    Although transvenous embolization (TVE) is an effective method for treating dural arteriovenous fistula (AVF), directing the catheter to the lesion site is difficult.We report on the utility of a quadruple coaxial catheter system for TVE.The quadruple catheter system comprised a 6 Fr guiding sheath, 6 Fr guiding catheter, 4 Fr intermediate catheter, and a regular microcatheter. The system was utilized in 27 consecutive dural AVF cases treated with TVE. In this study, we reviewed our experience with this system, including the theory, method of use, and complications.Stenosis or obstruction of the vascular access was identified in 12 cases. The catheter could not reach to the lesion in three cases of cavernous sinus (7·4%); therefore, transarterial embolization was employed. Angiographic results revealed that the cases consist of total occlusion (n  =  16, 59·5%), subtotal (n  =  10, 37·0%), and partial occlusion (n  =  1, 3·7%). Complete resolution or improvement of symptoms was observed in 23 patients (85·2%), no improvement of symptoms was observed in three patients (7·4%), and deterioration of symptoms was observed in one patient (3·7%). Venous perforation occurred in one patient without any neurological deficit. The catheter system provided access to the lesion and provided stability during the mechanically demanding process navigating the catheter and placing the coils.We determined that the quadruple coaxial system was safe and efficient for TVE for dural AVF.

    View details for DOI 10.1179/1743132814Y.0000000453

    View details for Web of Science ID 000347918400007

    View details for PubMedID 25323528

  • Bow Hunter's Stroke Due to Stretching of the Vertebral Artery Fenestration: A Case Report. NMC case report journal Yamaguchi, S., Horie, N., Tsunoda, K., Tateishi, Y., Izumo, T., Hayashi, K., Tsujino, A., Nagata, I. 2015; 2 (1): 9–11


    Bow Hunter's syndrome is an unusual symptomatic vertebrobasilar insufficiency resulting from intermittent mechanical compression of the vertebral artery, and is rarely a trigger for cerebral infarction following thrombus formation on the damaged endothelial vessels (Bow Hunter's stroke). The authors present an extremely rare case of a 45-year-old man showing Bow Hunter's stroke due to congenital vertebral artery fenestration stretching and sliding between C1 and C2 after head rotation to the right. Congenital vertebral artery anomaly rarely causes cerebral infarction, but could cause embolic strokes by mechanical stretching without bony abnormalities.

    View details for DOI 10.2176/nmccrj.2014-0075

    View details for PubMedID 28663954

    View details for PubMedCentralID PMC5364926

  • Pathophysiology of flow impairment during carotid artery stenting with an embolus protection filter ACTA NEUROCHIRURGICA Hayashi, K., Horie, N., Morikawa, M., Yamaguchi, S., Fukuda, S., Morofuji, Y., Izumo, T., Nagata, I. 2014; 156 (9): 1721–28


    Carotid artery stenting (CAS) is a well-accepted treatment for atherosclerotic stenosis of carotid arteries. Since the occurrence of distal embolization with CAS is still a major concern embolus protection devices (EPD) are usually employed during the procedure. We examined two types of embolus protection filters (Angioguard XP (AG); Filterwire EZ (FW)) and evaluated the function. Thus, the filter was examined postoperatively and the cause of intraoperative flow impairment was evaluated.CAS was performed for 54 patients with carotid artery stenosis (55 lesions: 25 AG; 27 FW; 3 others). After completing CAS the filter membrane was stained with hematoxylin-eosin (HE) solution and removed from the filter strut. Once mounted on a glass slide the filter was evaluated under a microscope. The area occupied with debris was measured and the relationship to intraoperative flow impairment was evaluated. Furthermore, the relationship between perioperative ischemic complications and intraoperative flow impairment was statistically analyzed.Microscopic observation of the slide revealed the pore density of the FW was 1.5 times higher than that of the AG and the filter area of the FW was 2.5 times wider than than the AG. HE staining facilitated characterization of the debris composition. The area occupied with debris was significantly more in the AG (0.241 ± 0.13 cm(2)) than in the FW (0.129 ± 0.093 cm(2)). Thus, fibrin was significantly more precipitated in the AG. Flow impairment occurred in 6 AG cases (24.0 %) and 4 FW cases (14.8 %). It was induced by filter obstruction in the AG and by vasospasms in the FW. Three cases treated with AG (12.0 %) were complicated with cerebral infarction and all of them were related to flow impairment. One FW case (3.7 %) was complicated with cerebral infarction in presence of preserved flow throughout the intervention.Filter function is different according to each design. The cause of flow impairment was attributable to filter obstruction in the AG group and to vasospasms in the FW group. Filter obstruction tends to result in cerebral infarction.

    View details for DOI 10.1007/s00701-014-2180-z

    View details for Web of Science ID 000340602400013

    View details for PubMedID 25037465

  • The Stent placement for acute basilar artery occlusion in Japan Journal of Neurological Disorders & Stroke Yamaguchi, S., Hayashi, K., Horie, N., Tateishi, Y., Fukuda, S., Izumo, T., Tsujino, A., Nagata, I. 2014; 2 (2): 1049
  • A case of emergent carotid artery stenting and thrombectomy with penumbra system for tandem internal carotid artery occlusion: case report Journal of Neuroendovascular Therapy Yamaguchi, S., Horie, N., Hayashi, K., Debata, A., Fukuda, S., Morofuji, Y., HIu, T., Izumo, T., Nagata, I. 2014; 8 (4): 231-237
  • Percutaneous transluminal angioplasty for atherosclerotic stenosis of the subclavian or innominate artery: angiographic and clinical outcomes in 36 patients NEUROSURGICAL REVIEW Miyakoshi, A., Hatano, T., Tsukahara, T., Murakami, M., Arai, D., Yamaguchi, S. 2012; 35 (1): 121–25


    The purpose of the study was to evaluate stenting and percutaneous transluminal angioplasty (PTA) for the treatment of stenotic lesions of the subclavian or innominate artery based on surgical results and long-term follow-up with 36 patients. In particular, we evaluated the efficacy of self-expanding stents compared to balloon-expandable stents. Between February 2000 and March 2008 at the Kyoto Medical Center, 36 patients underwent both stenting and PTA of the subclavian or innominate artery. Twenty-four patients had severe subclavian stenotic disease, ten patients had total occlusion of the subclavian artery, and two patients had stenoses of the innominate artery. Successful dilatation (less than 30% residual stenosis) was obtained in 34 of the 36 cases. In two cases (20%) of total subclavian occlusion, the guidewires were not able to penetrate the lesions, although the success rate was 100% for stenoses. All patients had no signs of neurological side effects with the exception of two pseudoaneurysms of the femoral arteries that required surgical intervention. In the first 30 days after treatment, there were no strokes or deaths. Outpatient follow-up was done with 30 patients (83.3%) after a mean of 30.9 months (range 3-114). Among these 30 patients, four patients (13.3%) developed restenoses of over 50%. Restenoses occurred in 4 of 20 individuals (20%) who received balloon-expandable stents but were not observed in those who received self-expanding stents. Endovascular therapy for the subclavian and innominate arteries is less invasive and safer than open surgery, making it the preferable option. In this clinical period, the rate of restenosis using self-expanding stents was lower than the rate using balloon-expandable stents.

    View details for DOI 10.1007/s10143-011-0328-3

    View details for Web of Science ID 000301665100021

    View details for PubMedID 21643683

  • Characteristics of Carotid Plaque Findings on Ultrasonography and Black Blood Magnetic Resonance Imaging in Comparison with Pathological Findings Arai, D., Yamaguchi, S., Murakami, M., Nakakuki, T., Fukuda, S., Satoh-Asahara, N., Tsukahara, T., Tsukahara, T., Regli, L., Hanggi, D., Turowski, B., Steiger, H. J. SPRINGER-VERLAG WIEN. 2011: 15-+


    Criteria to decide whether carotid endarterectomy (CEA) or carotid artery stenting (CAS) is the best mode of therapy in a specific case of cervical carotid stenosis have not been established. Overall, recent randomized clinical trials have reported that the effect on the prevention of stroke is not significantly different between CEA and CAS. CEA is more appropriate than CAS for soft atherosclerotic plaques, since such soft plaques are associated with a high incidence of ischemic complications during CAS. Therefore identification of the plaque type with noninvasive preoperative examinations plays an important role for selecting the suitable surgical method, CEA or CAS.The objective of this study was to evaluate the association among findings of carotid ultrasonography (carotid US), black blood magnetic resonance imaging (BB-MRI), and the histopathological findings of plaque specimens removed during CEA, and secondly to consider whether these diagnostic tools are useful to predict the characteristics of carotid plaques.We investigated a total of 25 consecutive patients who underwent CEA from November 2008 to June 2010 at Kyoto Medical Center. We examined carotid plaque in 17 patients employing both carotid US and BB-MRI, 7 patients by carotid US, and 1 patient by BB-MRI. The plaque echogenicity was qualitatively assessed as low, intermediate, or high, and the MR signal intensity of the carotid plaque was classified as low or high compared with the intensity of the ipsilateral sternocleidomastoid muscle. The plaque specimens were macroscopically and pathophysiologically classified as soft or hard plaque.All low-echogenic plaques on carotid US were histologically soft plaques. The high-intensity plaques on T1-weighted imaging (T1WI) showed a tendency toward soft plaque. Thirteen of 14 plaques with high signal intensity on T1WI were morphologically soft. Eleven of 14 plaques with an intermediate echogenicity on carotid US were also morphologically soft.The findings of carotid ultrasonography and BB-MRI are closely associated with the CEA specimen's morphology. Ultrasonography alone is insufficient to diagnose the plaque type accurately in some patients. Employing both carotid US and BB-MRI is useful for evaluating the characteristics of carotid plaque.

    View details for DOI 10.1007/978-3-7091-0661-7_3

    View details for Web of Science ID 000304028500003

    View details for PubMedID 21691981

  • Indication for Surgical Treatment of Carotid Arterial Stenosis in High-Risk Patients Tsukahara, T., Fukuda, S., Nakakuki, T., Murakami, M., Arai, D., Yamaguchi, S., Tsukahara, T., Regli, L., Hanggi, D., Turowski, B., Steiger, H. J. SPRINGER-VERLAG WIEN. 2011: 21–24


    The indication for carotid endarterectomy (CEA) or carotid artery stenting (CAS) has not been established, although the beneficial effects of these surgical treatments for severe cervical carotid stenosis have been confirmed by clinical trial studies. We report our clinical results of CAS and CEA and suggest an appropriate treatment strategy, especially for high-risk patients. From January 2001 to December 2009, we treated 171 carotid lesions by CEA and 251 lesions by CAS. Stenosis was symptomatic in 68%, and the average stenotic rate was 83% in the CEA group. In the CAS group, stenosis was symptomatic in 62%, and the average stenotic rate was 65%. Stenosis was relieved in all cases after CEA or CAS. Surgical mortality with CEA and CAS was 0.6% (1/171) and 0.4% (1/251), respectively. Surgical morbidity by ischemic stroke with CEA and CAS was 2.9% (5/171) and 1.2% (3/251), respectively. Surgical morbidity was not increased in patients with medical risk factors. The long-term outcome after CAS was not inferior to that after CEA. In conclusion, carotid stenosis can be treated with comparably low morbidity and mortality rates using CEA or CAS even in high-risk patients when the method is appropriately selected considering the characteristics of the carotid stenosis.

    View details for DOI 10.1007/978-3-7091-0661-7_4

    View details for Web of Science ID 000304028500004

    View details for PubMedID 21691982

  • Stent Placement for Atherosclerotic Stenosis of the Vertebral Artery Ostium: Angiographic and Clinical Outcomes in 117 Consecutive Patients NEUROSURGERY Hatano, T., Tsukahara, T., Miyakoshi, A., Arai, D., Yamaguchi, S., Murakami, M. 2011; 68 (1): 108–16


    Although it is thought to be a safe treatment option, the main concerns related to treating vertebral artery ostium (VAO) stenosis with stents have been the rate of restenosis and the uncertain long-term results.To evaluate the angiographic and clinical results of stent placement for atherosclerotic stenosis of the VAO.One hundred seventeen consecutive patients with atherosclerotic VAO stenosis were treated with stent placement over a period of 12 years. All patients were retrospectively analyzed through the use of a prospectively collected database. The indication criteria for this treatment protocol were symptomatic severe VAO stenoses (> 60%) and asymptomatic severe VAO stenoses (> 60%) with incidentally detected infarction in the posterior circulation. The target diameter of stent dilatation from 1997 to 2000 was the normal vessel diameter just distal to the lesion. Moderate overdilation in the proximal portion of the stents has been performed since 2001.Successful dilatation was obtained in 116 of 117 cases. Transient neurological complications developed in 2 patients; however, no patients experienced any permanent neurological complications. One hundred four patients underwent follow-up angiography at 6 months after stenting. The restenosis rate at the 6-month follow-up was 9.6% (10 of 104). Until 2000, the restenosis rate after stenting was 13.3%. Since 2001, the restenosis rate has decreased to 4.5%. The median clinical follow-up period was 48 months. The annual rate of strokes in the posterior circulation was 0.95%.Stent placement for atherosclerotic VAO stenosis is considered to be a feasible and safe treatment and may be effective for stroke prevention. The moderate overdilation of stents may be an effective modality for the prevention of restenosis.

    View details for DOI 10.1227/NEU.0b013e3181fc62aa

    View details for Web of Science ID 000285288200039

    View details for PubMedID 21099720