Glymphatic System Impairment in the Advanced Stage of Moyamoya Disease.

Assessing the glymphatic system activity using diffusion tensor imaging analysis along with the perivascular space (DTI-ALPS) may be helpful to understand the pathophysiology of moyamoya disease (MMD). 63 adult patients with MMD and 20 healthy controls (HCs) were included for T1-weighted images, T2-FLAIR, pseudocontinuous arterial spin labeling, and DTI. 60 patients had digital subtraction angiography more than 6 months after combined revascularization. The Suzuki stage, postoperative Matsushima grade, periventricular anastomoses (PA), enlarged perivascular spaces (EPVS), deep and subcortical white matter hyperintensities (DSWMH), DTI-ALPS, cerebral blood flow (CBF), and cognitive scales of MMD patients were assessed. MMD patients were divided into early and advanced stage based on the Suzuki stage. We detected lower DTI-ALPS in patients with advanced stage relative to HCs (p = 0.046) and patients with early stage (p = 0.004), hemorrhagic MMD compared with ischemic MMD (p = 0.048), and PA Grade 2 compared with Grade 0 (p = 0.010). DTI-ALPS was correlated with the EPVS in basal ganglia (r = -0.686, p < 0.001), Suzuki stage (r = -0.465, p < 0.001), DSWMH (r = -0.423, p = 0.001), and global CBF (r = 0.300, p = 0.017) and cognitive scores (r = 0.343, p = 0.018). The DTI-ALPS of patients with good postoperative collateral formation was higher compared to those with poor postoperative collateral formation (p = 0.038). In conclusion, the glymphatic system was impaired in advanced MMD patients and may affected cognitive function and postoperative neoangiogenesis.

The effects of anastomoses between anterior and posterior circulation on postoperative prognosis of patients with moyamoya disease.

BACKGROUND: Moyamoya disease (MMD) is a chronic ischemic cerebrovascular disease. Collateral circulation in MMD has emerged as a research focus. Our aims were to assess the impact of anastomoses between the anterior and posterior circulations on the prognosis of MMD patients. METHODS: We reviewed the preoperative digital subtraction angiography images of patients with MMD who underwent revascularization surgery at our hospital between March 2014 and May 2020 and divided the patients into two groups: those with anastomoses (PtoA group) and those without anastomoses (non-PtoA group). The differences in follow-up (more than 6 months) collateral vessel establishment (Matsushima grade) and the modified Rankin Scale (mRS) were compared between the two groups as well as between the patients with different degrees of anastomoses. The early complications following revascularization were also compared between the two groups. RESULTS: This study included 104 patients with MMD, of which 38 were non-PtoA and 66 were PtoA. There were no significant differences in Matsushima score (P = 0.252) and mRS score (P = 0.066) between the two groups. In addition, Matsushima score (P = 0.243) and mRS score (P = 0.360) did not differ significantly between patients with different degrees of anastomoses. However, the non-PtoA group had a significantly higher rate of cerebral hyperperfusion syndrome (CHS) than the PtoA group (34.2% vs 16.7%, P = 0.041). CONCLUSION: MMD patients without anastomoses between anterior and posterior circulations preoperatively should be vigilant of the occurrence of CHS in the early stages after revascularization.

Comparison of Changes in Retinal Vascular Parameters and Density in Patients with Moyamoya Disease: A Retrospective Study.

INTRODUCTION: This study aimed to compare retinal vascular parameters and density in patients with moyamoya disease using the optical coherence tomography angiography. METHODS: This clinical trial totally enrolls 78 eyes from 39 participants, and all these patients with moyamoya disease (N = 13) are set as experimental group and participants with health who matched with age and gender are considered as the control group (N = 26). Then all these participants receive optical coherence tomography angiography detection. Participants' general data are collected and analyzed. Skeleton density (SD) value, vessel density (VD) value, fractal dimension (FD) value, vessel diameter index (VDI) value, foveal avascular zone (FAZ) value are analyzed. RESULTS: A total of 39 participants are included in this study. The SD value in the experimental group was significantly lower than that in control group (0.175 [0.166, 0.181] vs. 0.184 [0.175, 0.188], p = 0.017). Similarly, the VD value in the experimental group was significantly lower than that in the control group (0.333 [0.320, 0.350] vs. 0.354 [0.337, 0.364], p = 0.024). Additionally, the FD value in the experimental group was significantly lower than that in the control group (2.088 [2.083, 2.094] vs. 2.096 [2.090, 2.101], p = 0.022). As for the VDI and FAZ, VDI and FAZ values in the experimental group were lower than those in the control group, there was no significant difference in VDI and FAZ values between the two groups. CONCLUSIONS: Our study, using non-invasive and rapid OCTA imaging, confirmed decreased retinal vascular parameters and density in patients with moyamoya disease.

Assessment of MR blood-oxygen-level-dependent (BOLD) cerebrovascular reactivity under general anesthesia in children with moyamoya.

BACKGROUND: Moyamoya is a progressive, non-atherosclerotic cerebral arteriopathy that may present in childhood and currently has no cure. Early diagnosis is critical to prevent a lifelong risk of neurological morbidity. Blood-oxygen-level-dependent (BOLD) MRI cerebrovascular reactivity (CVR) imaging provides a non-invasive, in vivo measure of autoregulatory capacity and cerebrovascular reserve. However, non-compliant or younger children require general anesthesia to achieve BOLD-CVR imaging. OBJECTIVE: To determine the same-day repeatability of BOLD-CVR imaging under general anesthesia in children with moyamoya. MATERIALS AND METHODS: Twenty-eight examination pairs were included (mean patient age = 7.3 ± 4.0 years). Positive and negatively reacting voxels were averaged over signals and counted over brain tissue and vascular territory. The intraclass correlation coefficient (ICC), Wilcoxon signed-rank test, and Bland-Altman plots were used to assess the variability between the scans. RESULTS: There was excellent-to-good (≥ 0.59) within-day repeatability in 18 out of 28 paired studies (64.3%). Wilcoxon signed-rank tests demonstrated no significant difference in the grey and white matter CVR estimates, between repeat scans (all p-values > 0.05). Bland-Altman plots of differences in mean magnitude of positive and negative and fractional positive and negative CVR estimates illustrated a reasonable degree of agreement between repeat scans and no systematic bias. CONCLUSION: BOLD-CVR imaging provides repeatable assessment of cerebrovascular reserve in children with moyamoya imaged under general anesthesia.

SDF-1/CXCR4 axis participants in the pathophysiology of adult patients with moyamoya disease.

BACKGROUND: Moyamoya disease (MMD) is characterized by an abundance of moyamoya vessels; however, the precise mechanism driving the spontaneous angiogenesis of these compensatory vessels remains unclear. Previous research has established a link between the stromal cell-derived factor-1 (SDF-1)/ CXC receptor 4 (CXCR4) axis and angiogenesis under hypoxic conditions. Nevertheless, the alterations in this axis within the cerebrospinal fluid, arachnoid membranes and vascular tissue of MMD patients have not been fully investigated. METHODS: Our study enrolled 66 adult MMD patients and 61 patients with atherosclerotic vascular disease (ACVD). We investigated the SDF-1 concentration in cerebrospinal fluid (CSF) and CXCR4 expression level on the arachnoid membranes and vascular tissue. We utilized enzyme-linked immunosorbent assay and immunohistochemistr. Additionally, we cultured and stimulated human brain microvascular endothelial cells (HBMECs) and smooth muscle cells (SMCs) under oxygen and glucose deprivation (OGD) conditions followed by reoxygenation, to examine any changes in the SDF-1/CXCR4 axis. RESULTS: The results demonstrated an elevation in the level of SDF-1 in CSF among MMD patients compared to those with ACVD. Moreover, the expression of CXCR4 in arachnoid membranes and vascular tissue showed a similar trend. Furthermore, the content of CXCR4 in HBMECs and SMCs increased with the duration of ischemia and hypoxia. However, it was observed that the expression of CXCR4 decreased at OGD/R 24h compared to OGD 24h. The temporal pattern of SDF-1 expression in HBMECs and SMCs mirrored that of CXCR4 expression. CONCLUSION: These findings indicate a critical role for the SDF-1/CXCR4 axis in the angiogenesis of moyamoya disease.

Worse outcome in hemorrhagic moyamoya disease of anterior circulation type compared to posterior circulation type.

OBJECTIVE: Despite the known poor outcomes of patients with hemorrhagic moyamoya disease (MMD), previous studies have not explored the entire population of hemorrhagic MMD, often excluding severely impaired patients due to the lack of imaging studies demonstrating cerebral angioarchitecture. Herein, we investigate the prevalence, location of intracerebral hematoma (ICH), and outcomes in patients with hemorrhagic MMD, including severely impaired individuals who underwent emergency computed tomography (CT) angiography (CTA) to identify secondary ICHs. METHODS: We conducted a retrospective analysis of 2092 patients admitted to our hospital within 3 days of ICH onset from January 2010 to December 2022. CTA was performed for all patients with ICH, principally. RESULTS: CTA was performed in 1645 (78.6%) patients. We diagnosed MMD in 40 patients (2.5%), making it the third leading cause of secondary ICH. Twenty patients had anterior-type hematomas, while the remaining twenty had posterior-type hematomas. At 90 days after onset, 19 patients (95%) with anterior-type hematomas had unfavorable outcomes (modified Rankin scale [mRS] scores of 3-6), compared to 11 patients (55%) with posterior-type hematomas. The number of unfavorable outcomes was significantly higher in the anterior-type group compared to the posterior-type group (p = 0.008). CONCLUSION: This comprehensive study highlights that the majority of MMD cases with ICH result in unfavorable outcomes, especially when the ICH is located in the anterior circulation. While recent studies have focused on preventing bleeding from choroidal anastomosis in the posterior circulation, overall outcome improvement of hemorrhagic MMD necessitates a greater emphasis on addressing anterior circulation ICHs.

EFFECT OF DIRECT SURGICAL REVASCULARIZATION ON CEREBRAL HEMODYNAMICS AND STROKE DEVELOPMENT IN PATIENTS WITH MOYAMOYA DISEASE.

Decreased cerebral blood flow (CBF) leads to impaired cerebral hemodynamics, which causes an increased risk of stroke. Revascularization has been shown to improve CBF in patients with moyamoya disease. The study is devoted to the retrospective study of clinical features and cerebral hemodynamic characteristics of 17 patients with moyamoya disease before, during and after surgical treatment using extracranial-intracranial (EC-IC) bypass by STA-MCA type. Patients underwent superficial temporal artery-middle cerebral artery bypass surgeries. All patients were carried out by DSA, MSCT-angiography, and MSCT-perfusion imagine (MSCTPI) before and 6 months after surgery. The hemodynamic parameters during MSCTPI, changes in cerebral vascular pattern, and clinical outcomes were evaluated. Cerebral blood flow and mean transit time (MTT) were measured using MSCT-perfusion imaging to identify areas of hypoperfusion. Intraoperative indocyanine green (ICG) analysis was performed to assess local cerebral hemodynamics before and after the creation of the STA-MCA bypass. Results showed that hemodynamics improved significantly on the surgery side after revascularization. After STA-MCA bypass CBF increased and MTT reduced by almost 2 times compared to the level before the bypass. The modified Rankin Scale scores demonstrated an improvement in the neurological status of patients following surgical revascularization. Thus, STA-MCA-type surgical revascularization significantly improved cerebral perfusion parameters and reduced the risk of stroke in patients with moyamoya disease. MSCTPI can serve as an effective and noninvasive method for monitoring cerebral hemodynamics in these patients. Intraoperative ICG angiography is a safe method that can display hemodynamic characteristics in the surgical area.

Changes in the clinical spectrum of pediatric moyamoya disease over 40 years.

OBJECTIVE: To investigate the chronological changes in the clinical presentation and long-term prognosis of pediatric-onset moyamoya disease in our institute over 40 years. METHODS: We evaluated 282 pediatric-onset (≤ 15 years old) moyamoya disease patients who visited our institute from 1981 to 2020 (divided into the former period, 1981-2000, and the latter period, 2001-2020). Differences in the clinical presentation and the long-term outcome were compared between the periods. Multivariate analysis was also performed to reveal the risk factors for poor long-term outcomes. RESULTS: Compared to the former period, the total number of patients, the onset age and both the number of patients with family history and relatively older patients without symptoms or with headache were greater in the latter period (p < 0.05). The number of patients with poor long-term outcomes was significantly lower in the latter period (24.9% vs. 6.7%, p < 0.01). Multivariate analysis revealed that stroke onset, late cerebrovascular events and postoperative complications were independent risk factors for poor long-term outcomes (odds ratio = 31.4, 40.8 and 5.4, respectively). CONCLUSIONS: Over the last 40 years, the number of pediatric moyamoya disease patients has increased, especially in relatively older patients with mild presentation and favorable long-term outcomes. In clinical studies, these chronological changes and the inclusion period of the participants need to be accounted for. Whether the increased diagnostic rate in the recent era has led to a decrease in late cerebrovascular events and favorable outcomes throughout life remains unknown and should be evaluated in the future.

Stroke mechanisms in adult moyamoya disease: The association between infarction patterns and quantitative magnetic resonance angiography flow state.

INTRODUCTION: Flow augmentation is the mainstay treatment for moyamoya disease as hemodynamic failure is believed to be the dominant mechanism. We aimed to investigate the mechanisms of stroke in moyamoya disease by assessing the relationship between infarction patterns and quantitative magnetic resonance angiography flow state. METHODS: A retrospective study of adult patients with suspected MMD who presented with MRI confirmed acute ischemic stroke predating or following QMRA by a maximum of six months between 2009 and 2021 was conducted. Of the 177 consecutive patients with MMD who received QMRA, 35 patients, consisting of 41 hemispheres, met inclusion criteria. Flow-status was dichotomized into low-flow and normal-flow state based on previously established criteria. RESULTS: Mixed infarction pattern was the most frequent finding (70.7 %), followed by embolic (17.1 %), perforator (7.3 %), and internal borderzone (IBZ) (4.9 %). Infarction patterns were further dichotomized into IBZ+ (internal borderzone alone or mixed) and IBZ- (no internal borderzone constituent). Low-flow states were not significantly more frequent in the IBZ+ compared to IBZ- population (48.4 % vs. 20.0 %, p = 0.14). Ipsilateral posterior cerebral artery fractional flow was significantly higher with IBZ+ compared to IBZ- (345.0 % vs. 214.7 %, p = 0.04). CONCLUSION: Mixed infarction pattern was the most common pattern of infarction in patients with moyamoya disease, implying hypoperfusion and thromboembolism are codominant stroke mechanisms. An association between ICA flow status and infarction pattern was not found, although QMRA evidence of more robust posterior cerebral artery leptomeningeal collaterals was found in patients with a hypoperfusion contribution to their stroke mechanism.

Angiographic and Hemodynamic Features in Asymptomatic Hemispheres of Patients With Moyamoya Disease.

BACKGROUND AND PURPOSE: There is also a risk of stroke in the asymptomatic hemispheres of moyamoya disease (MMD), but it does not draw enough attention. The study investigated the differences between the three types of asymptomatic hemispheres in MMD and their associations with the two types of symptomatic hemispheres, respectively. METHODS: Retrospectively reviewed clinical and imaging characteristics of asymptomatic and symptomatic hemispheres in consecutive cases of single-center MMD patients, with an emphasis on imaging characterization regarding vascular morphology and cerebral perfusion. MMD hemispheres were categorized into 5 types: hemorrhagic hemispheres, ischemic hemispheres, asymptomatic hemispheres in unilateral hemorrhagic MMD, asymptomatic hemispheres in unilateral ischemic MMD, and bilateral asymptomatic hemispheres in MMD. Angiographic feature was assessed by Suzuki's angiographic stage, while hemodynamic feature was assessed by preinfarction period stage. RESULTS: One hundred ninety-four MMD patients with 388 hemispheres were enrolled. Asymptomatic hemispheres in unilateral hemorrhagic MMD were largely similar to hemorrhagic hemispheres, both had more advanced Suzuki's angiographic stage and lower degree of hemodynamic failure compared with bilateral asymptomatic hemispheres in MMD and asymptomatic hemispheres in unilateral ischemic MMD. Asymptomatic hemispheres in unilateral ischemic MMD were similar to ischemic hemispheres, both had less advanced Suzuki's angiographic stage and higher degree of hemodynamic failure compared with bilateral asymptomatic hemispheres in MMD and asymptomatic hemispheres in unilateral hemorrhagic MMD. Bilateral asymptomatic hemispheres in MMD were different from the other hemispheres and had less advanced Suzuki's angiographic stage and lower degree of hemodynamic failure. CONCLUSIONS: The three types of asymptomatic hemispheres in MMD are defined and have unique angiographic and hemodynamic features. Different combinations of the two features can reflect the tendency of pathological evolution in these different asymptomatic hemispheres.

De Novo Cerebral Microbleeds and Cognitive Decline in Cerebral Hyperperfusion After Direct Revascularization for Adult Moyamoya Disease.

OBJECTIVES: Adult patients with moyamoya disease (MMD) occasionally develop cognitive decline due to cerebral hyperperfusion following direct revascularization surgery. However, how the hyperperfusion phenomenon contributes to declines in cognitive function remains unclear. The present supplementary analysis of a prospective study aimed to determine whether cerebral hyperperfusion following direct revascularization surgery for adult MMD with ischemic presentation and misery perfusion leads to development of de novo cerebral microbleeds (CMBs) and whether postoperative cognitive decline is related to these CMBs. MATERIALS AND METHODS: In total, 32 patients who underwent direct revascularization surgery also underwent T2*-weighted magnetic resonance imaging (T2*WI) and neuropsychological testing before and 2 months after surgery. Development of cerebral hyperperfusion and hyperperfusion syndrome following surgery was defined based on brain perfusion single-photon emission computed tomography (SPECT) findings and clinical symptoms. RESULTS: Cerebral hyperperfusion on brain perfusion SPECT (95% confidence interval [CI], 1.1-10.8; p = 0.0175) or cerebral hyperperfusion syndrome (95%CI, 1.3-15.3; p = 0.0029) was significantly associated with postoperatively increased CMBs on T2*WI. Postoperatively increased CMBs were significantly associated with postoperative cognitive decline (95%CI, 1.8-20.4, p = 0.0041). For patients with cerebral hyperperfusion on brain perfusion SPECT, the incidence of postoperative cognitive decline was significantly greater in patients with than in those without postoperatively increased CMBs (p = 0.0294). CONCLUSIONS: Cerebral hyperperfusion following direct revascularization surgery for adult MMD with ischemic presentation and misery perfusion contributes to the development of de novo CMBs and postoperative cognitive decline is related to these CMBs.

A practical modification to a resting state fMRI protocol for improved characterization of cerebrovascular function.

Cerebrovascular reactivity (CVR), defined here as the Blood Oxygenation Level Dependent (BOLD) response to a CO2 pressure change, is a useful metric of cerebrovascular function. Both the amplitude and the timing (hemodynamic lag) of the CVR response can bring insight into the nature of a cerebrovascular pathology and aid in understanding noise confounds when using functional Magnetic Resonance Imaging (fMRI) to study neural activity. This research assessed a practical modification to a typical resting-state fMRI protocol, to improve the characterization of cerebrovascular function. In 9 healthy subjects, we modelled CVR and lag in three resting-state data segments, and in data segments which added a 2-3 minute breathing task to the start of a resting-state segment. Two different breathing tasks were used to induce fluctuations in arterial CO2 pressure: a breath-hold task to induce hypercapnia (CO2 increase) and a cued deep breathing task to induce hypocapnia (CO2 decrease). Our analysis produced voxel-wise estimates of the amplitude (CVR) and timing (lag) of the BOLD-fMRI response to CO2 by systematically shifting the CO2 regressor in time to optimize the model fit. This optimization inherently increases gray matter CVR values and fit statistics. The inclusion of a simple breathing task, compared to a resting-state scan only, increases the number of voxels in the brain that have a significant relationship between CO2 and BOLD-fMRI signals, and improves our confidence in the plausibility of voxel-wise CVR and hemodynamic lag estimates. We demonstrate the clinical utility and feasibility of this protocol in an incidental finding of Moyamoya disease, and explore the possibilities and challenges of using this protocol in younger populations. This hybrid protocol has direct applications for CVR mapping in both research and clinical settings and wider applications for fMRI denoising and interpretation.

Longitudinal Reproducibility of CO2-Triggered BOLD MRI for the Hemodynamic Evaluation of Adult Patients with Moyamoya Angiopathy.

BACKGROUND AND PURPOSE: Hemodynamic evaluation of moyamoya patients is crucial to decide the treatment strategy. Recently, CO2-triggered BOLD MRI has been shown to be a promising tool for the hemodynamic evaluation of moyamoya patients. However, the longitudinal reliability of this technique in follow-up examinations is unknown. This study aims to analyze longitudinal follow-up data of CO2-triggered BOLD MRI to prove the reliability of this technique for long-term control examinations in moyamoya patients. METHODS: Longitudinal CO2 BOLD MRI follow-up examinations of moyamoya patients with and without surgical revascularization have been analyzed for all 6 vascular territories retrospectively. If revascularization was performed, any directly (by the disease or the bypass) or indirectly (due to change of collateral flow after revascularization) affected territory was excluded based on angiography findings (group 1). In patients without surgical revascularization between the MRI examinations, all territories were analyzed (group 2). RESULTS: Eighteen moyamoya patients with 39 CO2 BOLD MRI examinations fulfilled the inclusion criteria. The median follow-up between the 2 examinations was 12 months (range 4-29 months). For 106 vascular territories analyzed in group 1, the intraclass correlation coefficient was 0.784, p < 0.001, and for group 2 (84 territories), it was 0.899, p < 0.001. Within the total follow-up duration of 140 patient months, none of the patients experienced a new stroke. CONCLUSIONS: CO2 BOLD MRI is a promising tool for mid- and long-term follow-up examinations of cerebral hemodynamics in moyamoya patients. Systematic prospective evaluation is required prior to making it a routine examination.

A Novel Hyperspectral Imaging System for Intraoperative Prediction of Cerebral Hyperperfusion Syndrome after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis in Patients with Moyamoya Disease.

BACKGROUND: Postoperative cerebral hyperperfusion syndrome (CHS) may occur after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass for moyamoya disease (MMD). Predicting postoperative CHS is challenging; however, we previously reported the feasibility of using a hyperspectral camera (HSC) for monitoring intraoperative changes in brain surface hemodynamics during STA-MCA bypass. OBJECTIVE: To investigate the utility of HSC to predict postoperative CHS during STA-MCA bypass for patients with MMD. METHODS: Hyperspectral images of the cerebral cortex of 29 patients with MMD who underwent STA-MCA bypass were acquired by using an HSC before and after anastomosis. We then analyzed the changes in oxygen saturation after anastomosis and assessed its correlation with CHS. RESULTS: Five patients experienced transient neurological deterioration several days after surgery. 123I-N-Isopropyl-iodoamphetamine single-photon emission computed tomography scan results revealed an intense, focal increase in cerebral blood flow at the site of anastomosis without any cerebral infarction. Patients with CHS showed significantly increased oxygen saturation (SO2) in the cerebral cortex after anastomosis relative to those without CHS (33 ± 28 vs. 8 ± 14%, p < 0.0001). Receiver operating characteristic analysis results show that postoperative CHS likely occurs when the increase rate of cortical SO2 value is >15% (sensitivity, 85.0%; specificity, 81.3%; area under curve, 0.871). CONCLUSIONS: This study indicates that hyperspectral imaging of the cerebral cortex may be used to predict postoperative CHS in patients with MMD undergoing STA-MCA bypass.

A Retrospective Study of Neurological Complications in Pediatric Patients With Moyamoya Disease Undergoing General Anesthesia.

BACKGROUND: Moyamoya disease is a condition with potentially devastating and permanent neurological sequelae. Adequate volume status and blood pressure, tight control of carbon dioxide to achieve normocarbia, and providing postoperative analgesia to prevent hyperventilation are typical goals that are used during anesthetic care in these patients. The purpose of this study was to assess postanesthesia neurological complications in moyamoya patients undergoing general anesthesia for imaging studies and surgical procedures excluding neurosurgical revascularization. METHODS: We performed a retrospective cohort study examining moyamoya patients who received general anesthesia for imaging studies and nonneurosurgical-revascularization procedures between January 1, 2001 and December 1, 2016 at our quaternary care pediatric hospital. A general anesthetic encounter was excluded if it occurred within 30 days after a revascularization surgery. The electronic medical records of study patients were analyzed for perioperative management, and neurological outcomes within 30 days of an anesthetic were assessed. RESULTS: A total of 58 patients undergoing 351 anesthesia exposures were included in the study. Three patients experienced neurological complications, which included focal neurological weakness, seizure, and altered mental status. The incidence of complications during anesthesia encounters was 0.85% (3/351) with a 95% confidence interval of 0.28-2.62. CONCLUSIONS: Over a 16-year period at our hospital, 3 children with moyamoya disease who underwent anesthesia for nonneurosurgical-revascularization purposes demonstrated postanesthesia neurological symptoms. The symptoms were consistent with transient ischemic attacks and all resolved without long-term sequelae.

Crossed cerebellar diaschisis as an indicator of severe cerebral hyperperfusion after direct bypass for moyamoya disease.

Cerebral hyperperfusion (HP) complicates the postoperative course of patients with moyamoya disease (MMD) after direct revascularization surgery. Crossed cerebellar diaschisis (CCD) has been considered to be rarely associated with HP after revascularization surgery. This study aimed to describe the clinical features and factors associated with CCD secondary to cerebral HP after revascularization surgery for MMD. We analyzed 150 consecutive hemispheres including 101 in adults and 49 in pediatric patients who underwent combined direct and indirect bypass for MMD. Using single-photon emission computed tomography (SPECT), serial cerebral blood flow (CBF) was measured immediately after the surgery and on postoperative days 2 and 7. Pre- and postoperative voxel-based analysis of SPECT findings was performed to compare the changes in regional CBF. Multivariate logistic regression analysis was performed to test the effect of multiple variables on CCD. Asymptomatic and symptomatic HP was observed in 41.3% (62/150) and 16.7% (25/150) of the operated hemispheres, respectively. CCD was observed in 18.4% (16/87) of these hemispheres with radiological HP. Multivariate analysis revealed that the occurrence of CCD was significantly associated with symptomatic HP (p = 0.0015). Voxel-based analysis showed that the CBF increase in the operated frontal cortex, and the CBF reduction in the contralateral cerebellar hemisphere on day 7 were significantly larger in symptomatic HP than in asymptomatic HP (median 11.3% vs 7.5%; - 6.0% vs - 1.7%, respectively). CCD secondary to postoperative HP is more common than anticipated in MMD. CCD could potentially be used as an indicator of severe postoperative HP in patients with MMD.

Preoperatively estimated graft flow rate contributes to the improvement of hemodynamics in revascularization for Moyamoya disease.

OBJECTIVES: Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass operation is an effective treatment for patients with Moyamoya disease, and the hemodynamic parameters are reported to be improved after operation. However, there is no report concerning hemodynamic changes from the viewpoint of the preoperative anatomical structure of grafts. In this study, we evaluated the correlation between the preoperatively estimated blood flow of the graft obtained through image-based computational fluid dynamics (CFD) analysis and the hemodynamic changes in the acute phase after revascularization. MATERIALS AND METHODS: A total of 30 hemispheric sides of 23 patients were examined. The blood flow, that is, flow rate (FR) of the STA branches that were anastomosed to the MCA was evaluated using CFD analysis based on computed tomography (CT) angiography imaging data. The correlations between the FR and the hemodynamic changes in the acute phase after revascularization obtained through CT perfusion were assessed. RESULTS: The preoperatively estimated FR of the graft was moderately correlated with the changes in the mean transit time significantly and weakly correlated with those in the cerebral blood flow and cerebral blood volume. In addition, the FR was strongly correlated with age and the diameter of the STA from the origin to the bifurcation. CONCLUSION: The preoperatively estimated FR of the graft obtained through image-based CFD analysis contributed to the improvement of the mean transit time after revascularization. Because the FR of the graft was associated with the diameter of the STA, the size of the STA might be an important factor in postoperative hemodynamic changes. This might lead to the risk assessment of acute drastic hemodynamic changes as cerebral hyperperfusion, and consequently, better surgical outcomes might be expected.

Ameliorative Effects of Combined Revascularization Surgery on Abnormal Collateral Channels in Moyamoya Disease.

OBJECT: Abnormal collateral channels, so-called moyamoya vessels, play a critical role to compensate cerebral ischemia, but carry the risk for hemorrhagic stroke in moyamoya disease (MMD). The present study was aimed to clarify if superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and encephalo-myo-duro-arterio-pericranial synangiosis (EDMAPS) can efficiently regress the abnormal collateral channels in MMD patients. METHODS: This study included 92 hemispheres of 61 MMD patients who underwent STA-MCA anastomosis combined with EDMAPS between 2013 and 2019. There were 17 children and 44 adults. We retrospectively analyzed the findings on cerebral angiography before and 3 to 6 months after surgery, including Suzuki's angiographical stage, the development of surgical collaterals, and the extent of abnormal collateral channels such as lenticulostriate, thalamic, and choroidal channels. RESULTS: Following surgery, no pediatric and adult patients experienced any stroke during follow-up periods (40.2±25.5 and 54.9±19.7 months, respectively). Suzuki's stage significantly advanced in both adult and pediatric patients after surgery (P=0.042 and P<0.001). In adult patients, all of the lenticulostriate, thalamic, and choroidal channels significantly regressed after surgery (P<0.001, P=0.012, and P=0.004, respectively). In pediatric patients, however, lenticulostriate and choroidal channels significantly regressed (P=0.005 and P=0.034, respectively). Correlation analysis revealed that the development of surgical collaterals determined the postoperative regression of choroidal channels (P<0.001). CONCLUSION: STA-MCA anastomosis and EDMAPS may be one of the most effective procedures to widely provide surgical collaterals to the operated hemispheres and prevent not only ischemic but also hemorrhagic stroke by regressing the hemorrhage-prone abnormal collateral channels in MMD.

Additional Revascularization Using Multiple Burr Holes for PCA Involvement in Moyamoya Disease.

In specific cases of moyamoya disease (MMD), posterior cerebral artery (PCA) stenosis can develop after treatment of the anterior circulation and require additional revascularization. Here, we report two cases that underwent additional posterior indirect revascularization with multiple burr holes for PCA involvement after bilateral revascularization treatment of the anterior circulation. They presented with transient ischemic attack even after bilateral superficial temporal artery-middle cerebral artery bypass, and magnetic resonance angiography (MRA) showed that PCA stenosis had worsened. Indirect revascularization with multiple burr holes using Benz-marked skin incisions was performed. After surgery, the symptoms improved without perioperative complications, and cerebral angiography showed collateral circulation via the burr hole. Indirect revascularization for MMD is often combined with direct revascularization, and there are only a few reports on the use of multiple burr hole surgery alone. In addition, there are few reports of posterior circulation, despite the emphasis on the importance of PCA involvement in MMD. Indirect revascularization with multiple burr holes alone can be performed in multiple areas and applied to patients who cannot undergo direct revascularization using the occipital artery. The procedure is simple and less invasive than traditional direct revascularization procedures. Therefore, it can be effective, especially in pediatric cases of MMD with PCA involvement.

Individualized Perioperative Blood Pressure Management for Adult Moyamoya Disease: Experience from 186 Consecutive Procedures.

BACKGROUND: In adult patients with moyamoya disease (MMD) underwent combined revascularization, cerebral infarction during the acute postoperative phase is common and can lead to neurological dysfunction after revascularization in MMD patients. The aim of this study was to share the experience of individualized perioperative blood pressure (BP) management for adult MMD patients in one single center. METHODS: We retrospectively reviewed 144 adult patients with MMD who underwent 186 procedures of combined revascularization at our institution from March 2013 to July 2019. Clinical features and outcomes were analyzed, in particular regarding cerebral infarction and hyperperfusion syndrome (HPS). All of the patients received individualized management perioperatively, especially about the blood pressure management according to the characteristics of moyamoya disease. RESULTS: Postoperative cerebral infarction and HPS within 14 days after revascularization were recorded. Cerebral infarction occurred in four (2.1%) procedures among four patients. No patients suffered from a malignant cerebral infarction and only one patient had permanent neurological deficits. The incidence of HPS was 10.8% and no one presented with intracranial hemorrhage. All of the symptoms were reversible without any brain parenchymal injury. CONCLUSIONS: Our findings suggest that we can decrease the incidence and extent of cerebral infarction in adult MMD patients following combined revascularization by individualized perioperative BP management.