Showing papers by "Miki Fujimura published in 2017"

Angiographic features of hemorrhagic moyamoya disease with high recurrence risk: a supplementary analysis of the Japan Adult Moyamoya Trial

Abstract: OBJECTIVE In this paper, the authors set out to identify the angiographic features of moyamoya disease with posterior hemorrhage, which is a strong predictor of rebleeding. METHODS This cross-sectional study used the data set of the Japan Adult Moyamoya Trial (clinical trial registration no.: C000000166 [ www.umin.ac.jp/ctr/index.htm ]). The panel designed the ancillary measurement of angiography at onset, classifying the collateral vessels into 3 subtypes: lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. The association between each collateral and the hemorrhage site (anterior vs posterior) was assessed in the hemorrhagic hemisphere by using multivariate adjustment for potential confounders, including age, sex, and involvement of the posterior cerebral artery (PCA). The association was confirmed through topographical analysis of bleeding points. RESULTS Among the 80 participants, 75 hemorrhagic hemispheres of 75 patients were analyzed. Lenticulostriate anastomosis was detected in 21 (28.0%) hemorrhagic hemispheres, thalamic anastomosis in 22 (29.3%), and choroidal anastomosis in 35 (46.7%). Choroidal anastomosis was a factor associated with posterior hemorrhage (OR 2.77 [95% CI 1.08-7.10], p = 0.034) and remained statistically significant after the multivariate adjustment (OR 2.66 [95% CI 1.00-7.07], p = 0.049). PCA involvement was also associated with posterior hemorrhage in both univariate and multivariate analyses. Topographical analysis revealed good correspondence between bleeding points associated with positive choroidal anastomosis and the anatomical distribution of the choroidal arteries, including the thalamus and the wall of the atrium. CONCLUSIONS Choroidal anastomosis and PCA involvement are characteristic of posterior hemorrhage in moyamoya disease. Choroidal anastomosis might be considered a potential source of posterior hemorrhage at high risk of rebleeding.

Uneven cerebral hemodynamic change as a cause of neurological deterioration in the acute stage after direct revascularization for moyamoya disease: cerebral hyperperfusion and remote ischemia caused by the 'watershed shift'.

Abstract: Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is the standard surgical treatment for moyamoya disease (MMD). The main potential complications of this treatment are cerebral hyperperfusion (CHP) syndrome and ischemia, and their managements are contradictory to each other. We retrospectively investigated the incidence of the simultaneous manifestation of CHP and infarction after surgery for MMD. Of the 162 consecutive direct revascularization surgeries performed for MMD, we encountered two adult cases (1.2%) manifesting the simultaneous occurrence of symptomatic CHP and remote infarction in the acute stage. A 47-year-old man initially presenting with infarction developed CHP syndrome (aphasia) 2 days after left STA-MCA anastomosis, as assessed by quantitative single-photon emission computed tomography (SPECT). Although lowering blood pressure ameliorated his symptoms, he developed cerebral infarction at a remote area in the acute stage. Another 63-year-old man, who initially had progressing stroke, presented with aphasia due to focal CHP in the left temporal lobe associated with acute infarction at the tip of the left frontal lobe 1 day after left STA-MCA anastomosis, when SPECT showed a paradoxical decrease in cerebral blood flow (CBF) in the left frontal lobe despite a marked increase in CBF at the site of anastomosis. Symptoms were ameliorated in both patients with the normalization of CBF, and there were no further cerebrovascular events during the follow-up period. CHP and cerebral infarction may occur simultaneously not only due to blood pressure lowering against CHP, but also to the ‘watershed shift’ phenomenon, which needs to be elucidated in future studies.

Preventive Effect of Clazosentan against Cerebral Vasospasm after Clipping Surgery for Aneurysmal Subarachnoid Hemorrhage in Japanese and Korean Patients

Abstract: Background: Clazosentan has been explored worldwide for the prophylaxis of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH). In a dose-finding t

Impact of bifurcation angle and inflow coefficient on the rupture risk of bifurcation type basilar artery tip aneurysms.

Abstract: OBJECTIVE Risk factors for aneurysm rupture have been extensively studied, with several factors showing significant correlations with rupture status. Several studies have shown that aneurysm shape and hemodynamics change after rupture. In the present study the authors investigated a static factor, the bifurcation angle, which does not change after rupture, to understand its effect on aneurysm rupture risk and hemodynamics. METHODS A hospital database was retrospectively reviewed to identify patients with cerebral aneurysms treated surgically or endovascularly in the period between 2008 and 2015. After acquiring 3D rotational angiographic data, 3D stereolithography models were created and computational fluid dynamic analysis was performed using commercially available software. Patient data (age and sex), morphometric factors (aneurysm volume and maximum height, aspect ratio, bifurcation angle, bottleneck ratio, and neck/parent artery ratio), and hemodynamic factors (inflow coefficient and wall shear stress) were statistically compared between ruptured and unruptured groups. RESULTS Seventy-one basilar tip aneurysms were included in this study, 22 ruptured and 49 unruptured. Univariate analysis showed aspect ratio, bifurcation angle, bottleneck ratio, and inflow coefficient were significantly correlated with a ruptured status. Logistic regression analysis showed that aspect ratio and bifurcation angle were significant predictors of a ruptured status. Bifurcation angle was inversely correlated with inflow coefficient (p < 0.0005), which in turn correlated directly with mean (p = 0.028) and maximum (p = 0.014) wall shear stress (WSS) using Pearson's correlation coefficient, whereas aspect ratio was inversely correlated with mean (0.012) and minimum (p = 0.018) WSS. CONCLUSIONS Bifurcation angle and aspect ratio are independent predictors for aneurysm rupture. Bifurcation angle, which does not change after rupture, is correlated with hemodynamic factors including inflow coefficient and WSS, as well as rupture status. Aneurysms with the hands-up bifurcation configuration are more prone to rupture than aneurysms with other bifurcation configurations.

Embolization of the choroidal artery in the treatment of cerebral arteriovenous malformations.

Abstract: OBJECTIVE The anterior and posterior choroidal arteries are often recruited to supply arteriovenous malformations (AVMs) involving important paraventricular structures, such as the basal ganglia, internal capsule, optic radiation, lateral geniculate body, and medial temporal lobe. Endovascular embolization through these arteries is theoretically dangerous because they supply eloquent territories, are of small caliber, and lack collaterals. This study aimed to investigate the safety and efficacy of embolization through these arteries. METHODS This study retrospectively reviewed 13 patients with cerebral AVMs who underwent endovascular embolization through the choroidal arteries between 2006 and 2014. Embolization was performed as a palliative procedure before open surgery or Gamma Knife radiosurgery. Computed tomography and MRI were performed the day after embolization to assess any surgical complications. The incidence and type of complications and their association with clinical outcomes were analyzed. RESULTS Decreased blood flow was achieved in all patients after embolization. Postoperative CT detected no hemorrhagic complications. In contrast, postoperative MRI detected that 4 of the 13 patients (30.7%) developed infarctions: 3 patients after embolization through the anterior choroidal artery, and 1 patient after embolization through the lateral posterior choroidal artery. Two of the 4 patients in whom embolization was from the cisternal segment of the anterior choroidal artery (proximal to the plexal point) developed symptomatic infarction of the posterior limb of the internal capsule, 1 of whom developed morbidity (7.7%). The treatment-related mortality rate was 0%. Additional treatment was performed in 12 patients: open surgery in 9 and Gamma Knife radiosurgery in 3 patients. Complete obliteration was confirmed by angiography at the last follow-up in 10 patients. Recurrent bleeding from the AVMs did not occur in any of the cases during the follow-up period. CONCLUSIONS Ischemic complications are possible following the embolization of cerebral AVMs through the choroidal artery, even with modern neurointerventional devices and techniques. Although further study is needed, embolization through the choroidal artery may be an appropriate treatment option when the risk of surgery or radiosurgery is considered to outweigh the risk of embolization.

Transient Global Cerebral Ischemia Induces RNF213, a Moyamoya Disease Susceptibility Gene, in Vulnerable Neurons of the Rat Hippocampus CA1 Subregion and Ischemic Cortex.

Abstract: The RING finger protein 213 (RNF213) is an important susceptibility gene for moyamoya disease (MMD) and is also implicated in other types of intracranial major artery stenosis/occlusion (ICAS); however, the role of RNF213 in the development of ICAS including MMD is unclear. The constitutive expression of the RNF213 gene is relatively weak in brain tissue, while information regarding the expression patterns of the RNF213 gene under cerebral ischemia, which is one of characteristic pathologies associated with ICAS, is currently limited. Our objective was to address this critical issue, and we investigated Rnf213 mRNA expression in rat brains after 5 minutes of transient global cerebral ischemia (tGCI) by occluding the common carotid arteries coupled with severe hypotension. Rnf213 gene expression patterns were investigated with in situ RNA hybridization and a real-time polymerase chain reaction (PCR) from 1 to 72 hours after tGCI. In situ RNA hybridization revealed a significant increase in Rnf213 mRNA levels in the hippocampus CA1 sub-region 48 hours after tGCI. The significant induction of the Rnf213 gene was also evident in the ischemic cortex. Double staining of Rnf213 mRNA with NeuN immunohistochemistry revealed Rnf213 hybridization signal expression exclusively in neurons. The real-time PCR analysis confirmed the induction of the Rnf213 gene after tGCI. The up-regulation of the Rnf213 gene in vulnerable neurons in the hippocampus CA1 after tGCI suggests its involvement in forebrain ischemia, which is an underlying pathology of MMD. Further investigations are needed to elucidate its exact role in the pathophysiology of ICAS including MMD.

Navigation-guided clipping of a de novo aneurysm associated with superficial temporal artery-middle cerebral artery bypass combined with indirect pial synangiosis in a patient with moyamoya disease

Abstract: De novo aneurysms associated with superficial temporal artery (STA)-middle cerebral artery (MCA) bypass are an extremely rare complication of direct revascularization surgery for moyamoya disease (MMD). The basic pathology of MMD includes fragility of the intracranial arterial wall characterized by medial layer thinness and waving of the internal elastic lamina. However, the incidence of newly formed aneurysms at the site of anastomosis currently remains unknown. Among 317 consecutive direct/indirect combined revascularization surgeries performed for MMD, we encountered a 52-year-old woman manifesting a de novo aneurysm adjacent to the site of anastomosis 11 years after successful STA-MCA bypass with encephalo-duro-myo-synangiosis (EDMS). Although the patient remained asymptomatic, the aneurysm gradually increased in diameter to more than 6 mm with the formation of a daughter sac, and a computational fluid dynamic study revealed low wall shear stress at the aneurysm dome. The patient underwent microsurgical clipping of the aneurysm using a neuro-navigation system that permitted the minimally invasive dissection of the temporal muscle flap used for EDMS at the site of the aneurysm without affecting pial synangiosis. The aneurysm was successfully occluded using a titanium clip without complications. The postoperative course was uneventful, and the patient was discharged without neurological deficits. De novo aneurysms associated with STA-MCA bypass for MMD may be safely treated with microsurgical clipping, even in cases initially managed by a combined revascularization procedure that includes complex pial synangiosis. We recommend the application of the neuro-navigation system for the maximum preservation of pial synangiosis during this procedure.

De Novo Development of Moyamoya Disease in an Adult Female with a Genetic Variant of the RNF-213 Gene: Case Report

Abstract: Background The de novo development of moyamoya disease (MMD) in adults is extremely rare, with only 2 cases being previously reported. Furthermore, the mechanisms underlying the progression of adult MMD have not been elucidated yet. Case report A transient ischemic attack occurred in a 46-year-old woman, owing to progressive MMD. Magnetic resonance (MR) angiography performed 7 years before the diagnosis of MMD did not detect any steno-occlusive changes in the major intracranial vessels, including the internal carotid artery (ICA) and the middle cerebral artery (MCA). However, during the last 2 years, serial MR angiography revealed the gradual progression of left MCA stenosis and ultimately showed apparent stenosis of the bilateral terminal ICA to proximal MCA. Catheter angiography confirmed the definitive diagnosis of MMD. A genetic analysis of RING-finger protein (RNF)-213, an MMD susceptibility gene, revealed that not only the patient, but also her sister, brother, and daughter had the heterozygous variant of the RNF-213 gene. Because of hemodynamic compromise with ischemic symptoms, the patient underwent revascularization surgery on the affected hemisphere, without complications. She had no cerebrovascular event in the postoperative follow-up period of 8 months, and there was no evidence of the further progression of MMD. Conclusion We herein present the entire clinical course of the de novo development of MMD in a female adult. Newly developed MMD in an adult patient with a characteristic variant of the RNF-213 gene appears to be unique.

Revascularization of the anterior cerebral artery by Y-shaped superficial temporal artery interposition graft for the treatment of a de novo aneurysm arising at the site of A3-A3 bypass: technical case report.

Abstract: The most frequently used option to reconstruct the anterior cerebral artery (ACA) is an ACA-ACA side-to-side anastomosis. The long-term outcome and complications of this technique are unclear. The authors report a case of a de novo aneurysm arising at the site of A3-A3 anastomosis. A 53-year-old woman underwent A3-A3 side-to-side anastomosis for the treatment of a ruptured right A2 dissecting aneurysm. At 44 months after surgery, a de novo aneurysm developed at the site of anastomosis. The aneurysm developed in the front wall of the anastomosis site, and projected to the anterosuperior direction. A computational fluid dynamics (CFD) study showed the localized region with high wall shear stress coincident with the pulsation in the front wall of the anastomosis site, where the aneurysm developed. A Y-shaped superficial temporal artery (STA) interposition graft was used successfully to reconstruct both ACAs, and then the aneurysm was trapped. To the authors' knowledge, this is the first case of a de novo aneurysm that developed at the site of an ACA-ACA side-to-side anastomosis. A CFD study showed that hemodynamic stress might be an underlying cause of the aneurysm formation. A Y-shaped STA interposition graft is a useful option to treat this aneurysm. Long-term follow-up is necessary to detect this rare complication after ACA-ACA anastomosis.

Temporal and Spatial Changes in Cerebral Blood Flow during Management for Preventing Delayed Cerebral Ischemia after Aneurysmal Subarachnoid Hemorrhage: Serial Semiquantitative Analysis.

Abstract: Background Delayed cerebral ischemia is a major cause of morbidity after aneurysmal subarachnoid hemorrhage. The management for preventing the delayed cerebral ischemia is clinically difficult because of its multifactorial nature. We tested the hypothesis that spatial and temporal changes of regional cerebral blood flow after subarachnoid hemorrhage might relate to the incidence of the delayed cerebral ischemia and the clinical outcome. Methods Eighty-eight patients who underwent single-photon emission computed tomography twice during 14 days after the onset of aneurysmal subarachnoid hemorrhage were retrospectively analyzed. Regional cerebral blood flow was automatically analyzed in statistical imaging analyses using 3-dimensional stereotaxic region of interest template and 3-dimensional stereotaxic surface projection. Ratios were calculated by dividing the regional cerebral blood flow of patients by that of normal volunteers. We assessed the relation of changes in regional cerebral blood flow with the development of the delayed cerebral ischemia and the clinical outcome at 3 months. Results The regional cerebral blood flow of areas that eventually contained infarction significantly decreased, whereas those with significant increase were associated with transient neurological symptoms during the management for the delayed cerebral ischemia. Patients with both areas of regional cerebral blood flow increasing and decreasing during this period had worse outcomes than patients with a unidirectional change. Conclusions Cerebral perfusion may change temporally and spatially during the management for preventing the delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage. Regional hypoperfusion refractory to the management might exist, which could impact on the clinical outcome. An additional therapeutic approach targeting on such regions may be required.

Intra-operative hemorrhage due to hyperperfusion during direct revascularization surgery in an adult patient with moyamoya disease: a case report

Abstract: Hemorrhagic complication is one of the notable surgical complications of the revascularization surgery for moyamoya disease (MMD). Cerebral hyperperfusion (CHP) has been considered as the underlying cause of this complication. It mostly occurs several days after surgery, but the intra-operative hemorrhage immediately after bypass has not been reported previously. A 21-year-old woman presented right thalamic hemorrhage and was diagnosed as having MMD by cerebral angiography. In light of the location of the hemorrhage at the vascular territory of posterior circulation and the manifestation of transient ischemic attack during the follow-up period, she underwent revascularization surgery to prevent future ischemic attack and rebleeding. Superficial temporal artery (STA) was uneventfully anastomosed to the temporal M4 branch of the middle cerebral artery in an end-to-side manner. A few minutes after the completion of the anastomosis, hemorrhage occurred in the fissure adjacent to the site of anastomosis. Indocyanine green (ICG) video angiography just before hemorrhage showed focal early filling through the STA graft with early venous filling around the site of the anastomosis. The bleeding was controlled by immediate hypotensive therapy (systolic blood pressure 117 to 91 mmHg). The mean blood flows of the STA graft measured by ultrasonic flowmetry before and after hypotensive therapy were 52.8 and 24.2 ml/min, respectively. Single-photon emission computed tomography (SPECT) on the next day after surgery showed focal hyperperfusion in the surgical side. Intra-operative ultrasonic flowmetry, ICG, and postoperative SPECT would explain that CHP was the potential cause of the hemorrhagic complication. This is the first case describing intra-operative hemorrhagic complication during revascularization surgery for MMD. Surgeons need to be aware of this rare complication and its management method.

Successful presurgical endovascular management of venous sinus thrombosis associated with high-grade cerebral arteriovenous malformation: A case report:

Abstract: We report a case of a 39-year-old man presenting with a high-grade left parieto-occipital arteriovenous malformation (AVM) complicated by superior sagittal sinus (SSS) stenosis, seven years after the first presentation. Magnetic resonance imaging revealed a newly developed perilesional edema. Venous sinus stenosis acutely progressed to occlusion and induced multiple intracerebral hemorrhages. An emergent balloon venoplasty of the SSS successfully recanalized the thrombosed sinus. Further, multistage transarterial nidus embolization was performed followed by surgical resection, resulting in a complete eradication of the large AVM. The emergence of perilesional edema is a key radiological feature for the early recognition of a newly developed venous drainage route disturbance, which would result in hemorrhagic events. Venous sinus thrombosis is a rare cause of drainage route disturbance in cerebral AVMs. For such cases, the recanalization of venous drainage concomitant with flow reduction by performing transarterial embolization is effective in preventing further hemorrhage, which enables a safe performance of subsequent radical surgery.

Endoscopic third ventriculostomy for hydrocephalus in a patient with Klippel-Feil syndrome: a case report.

Abstract: A patient with Klippel-Feil syndrome presented with hydrocephalus secondary to intraventricular hemorrhage. Fusion of the cervical vertebrae may have impeded cerebrospinal fluid flow. Change in the properties of cerebrospinal fluid flow after hemorrhage may have induced noncommunicating hydrocephalus. Endoscopic third ventriculostomy was effective for the treatment of hydrocephalus associated with Klippel-Feil syndrome.

Pathological Investigation on RNF213: Animal Models of Rnf213-Knockout and Knock-in Mice

Abstract: Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by a progressive stenosis at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain. Although its etiology is undetermined, recent genome-wide and locus-specific association studies identified RNF213 as an important susceptibility gene for MMD among East Asian population. A polymorphism in c.14576G>A in RNF213 was evident in almost all of the familial patients with MMD and 80% of sporadic cases, but the exact role of RNF213 polymorphism in the development of MMD remains unknown. To answer this question, we generated genetically engineered mice lacking Rnf213 by homologous recombination (Rnf213-knockout mice), as well as Rnf213-knock-in mice expressing a missense mutation in mouse Rnf213, p. R4828K, corresponding to human RNF213, p. R4859K, in MMD patients. Although both mice did not spontaneously develop MMD up to 64 weeks of age as shown by high-resolution magnetic resonance angiography and carbon black injection analysis of the circle of Willis, the biological response of these mice under a variety of insults, such as ischemia or immunological stimuli, provided new insights for the pathogenesis of this rare entity.

Application of actuator-driven pulsed water jet in aneurysmal subarachnoid hemorrhage surgery: its effectiveness for dissection around ruptured aneurysmal walls and subarachnoid clot removal

Abstract: In clipping surgery for aneurysmal subarachnoid hemorrhage (aSAH), critical steps include clot removal and dissection of aneurysms without premature rupture or brain injuries. To pursue this goal, a piezo actuator-driven pulsed water jet (ADPJ) system was introduced in this study. This study included 42 patients, who suffered aSAH and underwent clipping surgery. Eleven patients underwent surgery with the assistance of the ADPJ system (ADPJ group). In the other 31 patients, surgery was performed without the ADPJ system (Control group). The ADPJ system was used for clot removal and aneurysmal dissection. The clinical impact of the ADPJ system was judged by comparing the rate of premature rupture, degree of clot removal, and clinical outcomes. Intraoperatively, a premature rupture was encountered in 18.2 and 25.8% of cases in the ADPJ and control groups, respectively. Although the differences were not statistically significant, intraoperative observation suggested that the ADPJ system was effective in clot removal and dissection of aneurysms in a safe manner. Computed tomography scans indicated the achievement of higher degrees of clot removal, especially when the ADPJ system was used for cases with preoperative clot volumes of more than 25 ml (p = 0.047, Mann-Whitney U test). Clinical outcomes, including incidence of postoperative brain injury or symptomatic vasospasm, were similar in both groups. We described our preliminary surgical results using the ADPJ system for aSAH. Although further study is needed, the ADPJ system was considered a safe and effective tool for clot removal and dissection of aneurysms.