RNF213 p.Arg4810Lys Wild Type is Associated with De Novo Hemorrhage in Asymptomatic Hemispheres with Moyamoya Disease

Clinical implications of RNF213 genetic variants, other than p.Arg4810Lys, in moyamoya disease (MMD), remain unclear. This study aimed to investigate the association of RNF213 variants with clinical phenotypes in MMD. This retrospective cohort study collected data regarding the clinical characteristics of 139 patients with MMD and evaluated the angioarchitectures of 253 hemispheres using digital subtraction angiography at diagnosis. All RNF213 exons were sequenced, and the associations of clinical characteristics and angiographical findings with p.Arg4810Lys, p.Ala4399Thr, and other rare variants (RVs) were examined. Among 139 patients, 100 (71.9%) had p.Arg4810Lys heterozygote (GA) and 39 (28.1%) had the wild type (GG). Fourteen RVs were identified and detetcted in 15/139 (10.8%) patients, and p.Ala4399Thr was detected in 17/139 (12.2%) patients. Hemispheres with GG and p.Ala4399Thr presented with significantly less ischemic events and more hemorrhagic events at diagnosis (p = 0.001 and p = 0.028, respectively). In asymptomatic hemispheres, those with GG were more susceptible to de novo hemorrhage than those with GA (adjusted hazard ratio [aHR] 5.36) with an increased risk when accompanied by p.Ala4399Thr or RVs (aHR 15.22 and 16.60, respectively). Within the choroidal anastomosis-positive hemispheres, GG exhibited a higher incidence of de novo hemorrhage than GA (p = 0.004). The GG of p. Arg4810Lys was a risk factor for de novo hemorrhage in asymptomatic MMD hemispheres. This risk increased with certain other variants and is observed in choroidal anastomosis-positive hemispheres. A comprehensive evaluation of RNF213 variants and angioarchitectures is essential for predicting the phenotype of asymptomatic hemispheres in MMD.

Ischemic patterns and their angiographic risk factors in adult patients with moyamoya disease

OBJECTIVE

The present study aims to determine whether angiographic differences increase the risk of ischemic pattern among adult patients with moyamoya disease (MMD).

METHODS

From January 2020 to December 2021, we retrospectively enrolled 123 ischemic or asymptomatic adult patients diagnosed as MMD. Angiographic changes including Suzuki stage, moyamoya vessels, anterior choroidal artery (AChoA) dilatation, lenticulostriate artery (LSA) dilatation, posterior communicating artery (PcomA) dilatation, and posterior cerebral artery (PCA) involvement were evaluated for all patients.

RESULTS

Among the 123 participants, 35 ischemic patients and 88 asymptomatic patients were analyzed. There was no significant difference of Suzuki stage, AChoA dilatation, LSA dilatation, and PcomA dilatation between ischemic group and asymptomatic group. The grading of moyamoya vessels differed significantly but was not a factor associated with ischemic pattern after adjusting multiple related confounders. However, the frequency of PCA steno-occlusive changes in ischemic patients was statistically higher than that in asymptomatic patients (54.3% vs 34.1%, p = 0.039). Furthermore, PCA involvement was a risk factor associated with ischemic form and remained statistically significant after the multivariate adjustment (p = 0.033, 95% CI 1.092-8.310).

INTERPRETATION

PCA involvement is closely related to the presentation of ischemic stroke but other angiographic features had no association with ischemic pattern in adult MMD.

Evaluation of surgical revascularization procedure outcomes for adult Moyamoya disease: a computed tomography perfusion-based study

BACKGROUND

The effectiveness of surgical interventions, whether direct or indirect, for Moyamoya disease (MMD) remains controversial. This study aims to investigate CT perfusion (CTP) as an objective method to evaluate the outcomes of different surgical modalities for adult MMD.

METHODS

The clinical and imaging data of 41 patients who underwent superficial temporal artery-middle cerebral artery (STA-MCA) bypass and 43 who received encephaloduroarteriosynangiosis (EDAS) were retrospectively analyzed. Intra- and intergroup differences in the Modified Rankin Scale (mRS) score, the change in clinical symptoms, collateral grade, and CTP parameters pre- and postoperatively were compared.

RESULTS

The overall level of the change in clinical symptoms in the STA-MCA group was higher than in the EDAS group (p < 0.05). In the operative area, the relative cerebral blood flow (rCBF) was significantly higher whereas the relative time to peak (rTTP) and the relative mean transit time (rMTT) were significantly lower in the STA-MCA and EDAS groups postoperatively than preoperatively (all p < 0.05). In the ipsilateral frontal lobe and basal ganglia, the postoperative rCBF was significantly higher, and the rTTP was significantly lower than the preoperative in the STA-MCA group (all p < 0.05). The postoperative rCBF improvement was higher in each brain area for STA-MCA than in the EDAS group (all p < 0.05).

CONCLUSION

Highlighting the utility of CTP, this study demonstrates its effectiveness in assessing postoperative cerebral hemodynamic changes in adult MMD patients. STA-MCA yielded a larger postoperative perfusion area and greater improvement compared to EDAS, suggesting CTP's potential to elucidate symptom variation between two surgical revascularization procedures.

CRITICAL RELEVANCE STATEMENT

We analyzed computed tomography perfusion parameters in pre- and postoperative adult Moyamoya disease patients undergoing superficial temporal artery-middle cerebral artery bypass and encephaloduroarteriosynangiosis. Our findings suggest computed tomography perfusion's potential in objectively elucidating symptom variations between these surgical revascularization approaches for MMD.

KEY POINTS

• Postoperative perfusion improvement is only confined to the operative area after EDAS. • Besides the operative area, postoperative perfusion in the ipsilateral frontal lobe and basal ganglia was also improved after STA-MCA. • The degree of perfusion improvement in each brain area in the STA-MCA group was generally greater than that in the EDAS group.

Ethnic-Associated Phenotype Variations in Moyamoya Cerebrovascular Outcomes

INTRODUCTION

Moyamoya has been extensively described in East Asian populations, and despite its accepted clinical presentation and course, it is fundamental to describe major cerebrovascular complications in other ethnically diverse samples. Hence, we sought to determine if distinct ethnic groups are at higher risk of developing stroke using the National Inpatient Sample (NIS) database.

METHODS

We included all moyamoya patients admitted from January 2013 until December 2018 in the NIS database. Multivariate regression analysis was used to determine the risk of developing stroke and poor outcomes in different races compared to white patients.

RESULTS

Out of the 6093 admissions with diagnosis of moyamoya disease that were captured, 2,520 were white (41.6%), 2,078 were African American (AA) (34.1%), 721 were Hispanic (11.8%), and 496 were Asian (8.14%). For arterial ischemic stroke (AIS), we found that AA race had a significantly reduced risk of AIS compared to white patients (odds ratio = 0.8, 95% confidence interval: 0.7-0.9, p = 0.031). While being Hispanic or Asian significantly increased 1.5 and 2-fold the risk of hemorrhagic stroke.

CONCLUSION

This study highlights the unique features and phenotypes of moyamoya cases among different ethnicities. While possibly AA are protected from developing AIS due to underlying causes of moyamoya such as sickle cell disease, Asians seems to be more susceptible to hemorrhagic stroke.

Imaging features of adult moyamoya disease patients with anterior intracerebral hemorrhage based on high-resolution magnetic resonance imaging

This study aimed to identify the high-resolution magnetic resonance imaging (HRMRI) features of moyamoya disease (MMD) patients with anterior intracerebral hemorrhage (ICH) and attempted to reveal potential mechanisms of anterior ICH. Eligible adult MMD patients were consecutively included, and the morphological features of lenticulostriate arteries (LSAs), vessel wall structure of terminal internal carotid artery (ICA) and periventricular anastomosis were evaluated by HRMRI. 78 MMD patients containing 21 patients with anterior ICH, 31 ischemic patients and 26 asymptomatic patients were included. The mean value of total length of LSAs in anterior ICH group (90.79 ± 37.00 mm) was distinctively lower (p < 0.001) compared with either ischemic group (138.04 ± 46.01 mm) or asymptomatic group (170.50 ± 39.18 mm). Lumen area of terminal ICA was significantly larger (p < 0.001) in hemorrhagic group (4.33 ± 2.02 mm²) compared with ischemic group (2.29 ± 1.17 mm²) or asymptomatic group (3.00 ± 1.34 mm²). Multivariate analysis revealed the total length of LSAs (OR 0.689, 95%CI, 0.565-0.840; p < 0.001) and lumen area of terminal ICA (OR 2.085, 95%, 1.214-3.582; p = 0.008) were significantly associated with anterior ICH. Coexistence of reduced LSAs and relatively preserved lumen area of terminal ICA with an AUC of 0.901 (95%CI, 0.812-0.990) could be a potential predictor of anterior ICH in MMD patients.

Association of RNF213 Variants With Periventricular Anastomosis in Moyamoya Disease

BACKGROUND

The pathogenic mechanisms of periventricular anastomosis (PA) in moyamoya disease remain unknown. Here, we aimed to describe the angiographic profiles of PA and their relationships with really interesting new gene (RING) finger protein 213 (RNF213) genotypes.

METHODS

We conducted a retrospective cohort study of moyamoya disease patients consecutively recruited between June 2019 and January 2021 in Beijing Tiantan Hospital, Capital Medical University, China. C-terminal region of RNF213 was sequenced. Angiographic characteristics of PA vessels (lenticulostriate artery, thalamotuberal artery, thalamoperforating artery, anterior choroidal artery, and posterior choroidal artery) were compared between different groups of RNF213 genotypes. The dilatation and extension of PA vessels were measured by using PA score (positive, score 1-5; negative, score 0). Multivariate regression analysis was conducted to assess variables associated with PA score. In addition, gene expression of RNF213 in human brain regions was evaluated from the Allen Human Brain Atlas.

RESULTS

Among 260 patients (484 hemispheres), 71.2% carried no RNF213 rare and novel variants, 20.0% carried p.R4810K heterozygotes, and 8.8% carried other rare and novel variants. PA scores in patients with p.R4810K and other rare and novel variants were significantly higher than in wild-type patients (P<0.001). Age (odds ratio [OR], 0.958 [95% CI, 0.942-0.974]; P<0.001), platelet count (OR, 0.996 [95% CI, 0.992-0.999]; P=0.027), p.R4810K variant (OR, 2.653 [95% CI, 1.514-4.649]; P=0.001), other rare and novel variants (OR, 3.197 [95% CI, 1.012-10.094]; P=0.048), Suzuki stage ≥4 (OR, 1.941 [95% CI, 1.138-3.309]; P=0.015), and posterior cerebral artery involvement (OR, 1.827 [95% CI, 1.020-3.271]; P=0.043) were significantly correlated with PA score. High expression of RNF213 was detected in the periventricular area.

CONCLUSIONS

RNF213 variants were confirmed to be associated with PA in moyamoya disease. Individuals with RNF213 p.R4810K heterozygotes and other C-terminal region rare variants exhibited different angiographic phenotypes, compared with wild-type patients.

The Genetic Basis of Moyamoya Disease

Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by progressive spontaneous bilateral occlusion of the intracranial internal cerebral arteries (ICA) and their major branches with compensatory capillary collaterals resembling a “puff of smoke” (Japanese: Moyamoya) on cerebral angiography. These pathological alterations of the vessels are called Moyamoya arteriopathy or vasculopathy and a further distinction is made between primary and secondary MMD. Clinical presentation depends on age and population, with hemorrhage and ischemic infarcts in particular leading to severe neurological dysfunction or even death. Although the diagnostic suspicion can be posed by MRA or CTA, cerebral angiography is mandatory for diagnostic confirmation. Since no therapy to limit the stenotic lesions or the development of a collateral network is available, the only treatment established so far is surgical revascularization. The pathophysiology still remains unknown. Due to the early age of onset, familial cases and the variable incidence rate between different ethnic groups, the focus was put on genetic aspects early on. Several genetic risk loci as well as individual risk genes have been reported; however, few of them could be replicated in independent series. Linkage studies revealed linkage to the 17q25 locus. Multiple studies on the association of SNPs and MMD have been conducted, mainly focussing on the endothelium, smooth muscle cells, cytokines and growth factors. A variant of the RNF213 gene was shown to be strongly associated with MMD with a founder effect in the East Asian population. Although it is unknown how mutations in the RNF213 gene, encoding for a ubiquitously expressed 591 kDa cytosolic protein, lead to clinical features of MMD, RNF213 has been confirmed as a susceptibility gene in several studies with a gene dosage-dependent clinical phenotype, allowing preventive screening and possibly the  development of new therapeutic approaches. This review focuses on the genetic basis of primary MMD only.

Progression in Moyamoya Disease: Clinical Feature, Neuroimaging Evaluation and Treatment

Moyamoya disease (MMD) is a chronic cerebrovascular disease characterized by progressive stenosis of the arteries of the circle of Willis, with the formation of collateral vascular network at the base of the brain. Its clinical manifestations are complicated. Numerous studies have attempted to clarify the clinical features of MMD, including its epidemiology, genetic characteristics, and pathophysiology. With the development of neuroimaging techniques, various neuroimaging modalities with different advantages have deepened the understanding of MMD in terms of structural, functional, spatial, and temporal dimensions. At present, the main treatment for MMD focuses on neurological protection, cerebral blood flow reconstruction, and neurological rehabilitation, such as pharmacological treatment, surgical revascularization, and cognitive rehabilitation. In this review, we discuss recent progress in understanding the clinical features, in the neuroimaging evaluation and treatment of MMD.

Distinct Clinical and Radiographic Phenotypes in Pediatric Patients With Moyamoya

BACKGROUND

Given the expanding evidence of clinico-radiological differences between moyamoya disease (MMD) and moyamoya syndrome (MMS), we compared the clinical and radiographic features of childhood MMD and MMS to identify predictors of ischemic event recurrence.

METHODS

We reviewed a pediatric moyamoya cohort followed between 2003 and 2019. Clinical and radiographic characteristics at diagnosis and follow-up were abstracted. Comparisons between MMD and MMS as well as between MMD and two MMS subgroups (neurofibromatosis [MMS-NF1] and sickle cell disease [MMS-SCD]) were performed.

RESULTS

A total of 111 patients were identified. Patients with MMD presented commonly with transient ischemic attacks (TIAs) (35 % MMD versus 13% MMS-NF1 versus 9.5% MMS-SCD; P = 0.047). Symptomatic stroke presentation (MMD 37% versus MMS-NF1 4% versus 33%; P = 0.0147) and bilateral disease at diagnosis (MMD 73% versus MMS-NF1 22 % versus MMS-SCD 67%; P = 0.0002) were uncommon in MMS-NF1. TIA recurrence was common in MMD (hazard ratio 2.86; P = 0.001). The ivy sign was absent on neuroimaging in a majority of patients with MMS-SCD (MMD 67% versus MMS-NF1 52% versus MMS-SCD 9.5%; P = 0.0002). Predictors of poor motor outcome included early age at diagnosis (odds ratio [OR] 8.45; P = 0.0014), symptomatic stroke presentation (OR 6.6; P = 0.019), and advanced Suzuki stage (OR 3.59; P = 0.019).

CONCLUSIONS

Moyamoya exhibits different phenotypes based on underlying etiologies. Frequent TIAs is a common phenotype of MMD and symptomatic stroke presentation a common feature of MMD and MMS-SCD, whereas unilateral disease and low infarct burden are common in MMS-NF1. In addition, absence of ivy sign is a common phenotype in MMS-SCD.

Transdural Anastomotic Aneurysm in Association with Moyamoya Disease: A Rare and Troublesome Neurosurgical Entity

Moyamoya disease (MMD) is an idiopathic progressive steno-occlusive disease in the internal carotid artery (ICA) bifurcation. In rare circumstances, transdural anastomotic aneurysm (TAA) could develop during the progression of MMD. We present an illustrative case of TAA in association with MMD. To further explore this rare entity, a comprehensive literature review was also conducted. Our illustrative patient experienced spontaneous remission of the aneurysm during follow-up. By literature review, 12 patients with 13 TAAs, including our case, were identified. The patients aged from 10 to 74 years (46.3 ± 17.4). Eleven (92%) of the patients presented with intracranial hemorrhage, and 1 TAA (8%) was incidentally found. The responsible transdural collaterals were from the middle meningeal artery, occipital artery, internal maxillary artery, and ophthalmic artery in 8 (66.7%), 2 (16.7%), 1 (8%), and 2 (17%) patients, respectively. The anastomosed cerebral arteries were middle cerebral artery, anterior cerebral artery, posterior cerebral artery, and ICA in 5 (42%), 3 (25%), 3 (25%), and 1 (8%) patient, respectively. Eight (67%) patients underwent open surgeries. Two (17%) patients underwent transarterial embolization (TAE) only. Two (17%) patients experienced spontaneous remission of the aneurysm. Seven (58%) patients died or had neurologic deficits. TAAs rarely occur in the progression of MMD, which often presents with intracranial bleeding. Invasive management through open surgery or endovascular treatment is warranted to prevent catastrophic rebleeding. As some individuals might experience spontaneous aneurysm remission, conservative treatment and close imaging follow-up could be considered as an alternative when invasive treatment is risky.

Development and natural course of lateral posterior choroidal artery aneurysms arising from fragile choroidal collaterals in moyamoya disease: illustrative cases

BACKGROUND

Choroidal collaterals are a risk factor for hemorrhagic stroke, even in the nonhemorrhagic hemisphere, among patients with moyamoya disease (MMD). Peripheral choroidal aneurysms rupture in fragile collaterals; however, the development and natural course of these aneurysms remain elusive.

OBSERVATIONS

A 51-year-old woman, who had experienced a right cerebral hemorrhage 3 years earlier, presented with asymptomatic minor bleeding from a left lateral choroidal artery aneurysm in a predeveloped choroidal anastomosis. Although the aneurysm spontaneously thrombosed within 2 months, the choroidal collaterals persisted. After bypass surgery, the choroidal anastomosis regressed, and neither a de novo aneurysm nor a hemorrhagic stroke occurred. A 75-year-old woman with MMD, who had experienced a left frontal infarction 6 years earlier, experienced recurrent right intraventricular hemorrhage from a ruptured lateral choroidal artery aneurysm that developed in the choroidal anastomosis. The aneurysm spontaneously regressed 3 days after the rebleeding with no recurrence over the following 7 years.

LESSONS

Choroidal artery aneurysms may develop in the choroidal anastomosis and rupture in the nonsurgical or contralateral hemispheres. Patients with MMD who have a history of hemorrhagic or ischemic stroke and impaired cerebral blood flow require careful observation. Although aneurysms may rapidly regress spontaneously, bypass surgery can stabilize hemodynamic stress and prevent further hemorrhage.

The physiopathology of spontaneous hemorrhagic stroke: a systematic review

Hemorrhagic stroke (HS) is a major cause of death and disability worldwide, despite being less common, it presents more aggressively and leads to more severe sequelae than ischemic stroke. There are two types of HS: Intracerebral Hemorrhage (ICH) and Subarachnoid Hemorrhage (SAH), differing not only in the site of bleeding, but also in the mechanisms responsible for acute and subacute symptoms. This is a systematic review of databases in search of works of the last five years relating to the comprehension of both kinds of HS. Sixty two articles composed the direct findings of the recent literature and were further characterized to construct the pathophysiology in the order of events. The road to the understanding of the spontaneous HS pathophysiology is far from complete. Our findings show specific and individual results relating to the natural history of the disease of ICH and SAH, presenting common and different risk factors, distinct and similar clinical manifestations at onset or later days to weeks, and possible complications for both.

iTRAQ-based Quantitative Proteomic Analysis of Dural Tissues Reveals Upregulated Haptoglobin to be a Potential Biomarker of Moyamoya Disease

Background:

Moyamoya Disease (MMD) is a rare cerebrovascular disease with a high rate of disability and mortality. Immune reactions have been implicated in the pathogenesis of MMD, however, the underlying mechanism is still unclear.

Objective:

To identify proteins related to MMD specially involved in the immunogenesis, we performed a proteomic study.

Methods:

In this work, dural tissues or plasma from 98 patients with MMD, 17 disease controls without MMD, and 12 healthy donors were included. Proteomic profiles of dural tissues from 4 MMD and 4 disease controls were analyzed by an isobaric tag for relative and absolute quantitation (iTRAQ)- based proteomics. The immune-related proteins were explored by bioinformatics and the key MMDrelated proteins were verified by western blot, multiple reaction monitoring methods, enzyme-linked immunosorbent assay, and tissue microarray.

Results:

1,120 proteins were identified, and 82 MMD-related proteins were found with more than 1.5 fold difference compared with those in the control samples. Gene Ontology analysis showed that 29 proteins were immune-related. In particular, Haptoglobin (HP) was up-regulated in dural tissue and plasma of MMD samples compared to the controls, and its up-regulation was found to be sex- and MMD Suzuki grade dependent. Through Receiver Operating Characteristic (ROC) analysis, HP can well discriminate MMD and healthy donors with the Area Under the Curve (AUC) of 0.953.

Conclusion:

We identified the biggest protein database of the dura mater. 29 out of 82 differentially expressed proteins in MMD are involved in the immune process. Of which, HP was up-regulated in dural tissue and plasma of MMD, with sex- and MMD Suzuki grade-dependence. HP might be a potential biomarker of MMD.

Racial phenotypes in moyamoya disease: a comparative analysis of clinical presentation and natural history in a single multiethnic cohort of 250 hemispheres

OBJECTIVE

The authors aimed to determine whether differences exist in presentation and natural history when comparing Asian patients with moyamoya disease (MMD) to those of other ethnicities in North America.

METHODS

A database of 137 patients with MMD presenting to their institution between 1994 and 2015 was reviewed. Baseline characteristics and outcome variables, including stroke and functional outcome, were compared between Asian and non-Asian patients. Unadjusted Kaplan-Meier survival analysis and adjusted Cox regression models were used to compare stroke-free survival and stroke hazard after diagnosis among hemispheres of both racial groups. The analysis was stratified by age group, and censoring was performed until last follow-up or at the time of surgery. Because the relative rate of stroke changed between Asian and non-Asian adults after 1.5 years of follow-up, a time-segmented analysis focusing on the period 1.5 years after diagnosis was performed.

RESULTS

The cohort comprised 23% (31/137) Asian and 77% (106/137) non-Asian patients with MMD with a bimodal age distribution. Non-Asian patients had a higher prevalence of increased BMI (p = 0.02) and smoking (p = 0.04). Among patients who presented with stroke (n = 90), hemorrhage was significantly more common among Asians (p = 0.02). The natural history analysis included 250 hemispheres: 67 pediatric and 183 adult hemispheres. The overall mean follow-up duration since diagnosis was 3.3 years. Among adults, Asian patients had a higher incidence of stroke (8.0 per 100 person-years vs 3.0 per 100 person-years) over a mean follow-up of 3.3 years, but results were not statistically significant (p = 0.45). In the period beginning 1.5 years after diagnosis, Asian adults had a significantly higher hazard of stroke over a mean follow-up of 7.7 years, while controlling for sex, hypertension, and stroke before diagnosis (hazard ratio 8.8, p = 0.02). Among pediatric patients, Asians also had a higher stroke incidence (10.0 per 100 person-years vs 3.5 per 100 person-years) over a mean follow-up of 3.2 years; however, results did not reach statistical significance (p = 0.40). Functional outcome was similar between both ethnic groups at last follow-up (p = 0.57).

CONCLUSIONS

This study suggests a comparatively more progressive course of MMD in Asians. Further studies are required to fully characterize the phenotypic distinctions between different races and underlying pathophysiological mechanisms.

Cortical Distribution of Fragile Periventricular Anastomotic Collateral Vessels in Moyamoya Disease: An Exploratory Cross-Sectional Study of Japanese Patients with Moyamoya Disease

BACKGROUND AND PURPOSE

Collateral vessels in Moyamoya disease represent potential sources of bleeding. To test whether these cortical distributions vary among subtypes, we investigated cortical terminations using both standardized MR imaging and MRA.

MATERIALS AND METHODS

Patients with Moyamoya disease who underwent MR imaging with MRA in our institution were enrolled in this study. MRA was spatially normalized to the Montreal Neurological Institute space; then, collateral vessels were measured on MRA and classified into 3 types of anastomosis according to the parent artery: lenticulostriate, thalamic, and choroidal. We also obtained the coordinates of collateral vessel outflow to the cortex. Differences in cortical terminations were compared among the 3 types of anastomosis.

RESULTS

We investigated 219 patients with Moyamoya disease, and a total of 190 collateral vessels (lenticulostriate anastomosis, n = 72; thalamic anastomosis, n = 21; choroidal anastomosis, n = 97) in 46 patients met the inclusion criteria. We classified the distribution patterns of collateral anastomosis as follows: lenticulostriate collaterals outflowing anteriorly (P < .001; 95% CI, 67.0-87.0) and medially (P < .001; 95% CI, 11.0-24.0) more frequently than choroidal collaterals; lenticulostriate collaterals outflowing anteriorly more frequently than thalamic collaterals (P < .001; 95% CI, 34.0-68.0); and choroidal collaterals outflowing posteriorly more frequently than thalamic collaterals (P < .001; 95% CI, 14.0-34.0). Lenticulostriate anastomoses outflowed to the superior or inferior frontal sulcus and interhemispheric fissure. Thalamic anastomoses outflowed to the insular cortex and cortex around the central sulcus. Choroidal anastomoses outflowed to the cortex posterior to the central sulcus and the insular cortex.

CONCLUSIONS

Cortical distribution patterns appear to differ markedly among the 3 types of collaterals.

Hemorrhagic patterns and their risk factors in patients with moyamoya disease

BACKGROUND AND PURPOSE

The aim was to describe the profiles of hemorrhagic patterns of moyamoya disease (MMD) and analyze the risk factors in a large population.

METHODS

A total of 335 conservatively managed MMD patients with hemorrhage in our hospital were included in this cross-sectional study. The correlation between clinical and angiographic characteristics and hemorrhagic patterns (anterior or posterior hemorrhage) was assessed in the hemorrhagic hemisphere by univariate and multivariate logistic regression models. In addition, stratified analysis was performed.

RESULTS

The 335 hemorrhagic hemispheres (patients) comprised 179 (53.4%) anterior and 156 (46.6%) posterior hemorrhages. For all cases, age at onset [odds ratio (OR) 0.98; 95% confidence interval (CI) 0.96-1.00; P = 0.048] and choroidal anastomosis (OR 1.87; 95% CI 1.19-2.94; P = 0.007) were found by multivariate regression analysis to be negatively and positively associated with a significantly increased risk of posterior hemorrhage, respectively. After stratified analysis, hypertension (OR 0.37; 95% CI 0.14-0.97; P = 0.043) was identified by multivariate regression analysis as a risk factor for anterior hemorrhage in patients without dilation of choroidal anastomosis. On the other hand, choroidal anastomosis (OR 2.62; 95% CI 1.02-6.72; P = 0.045) and involvement of the posterior cerebral artery (OR 3.39; 95% CI 1.20-9.63; P = 0.022) were associated with significantly increased risk of posterior hemorrhage in children and young adults (<30 years of age).

CONCLUSIONS

A dynamic change in hemorrhagic patterns in MMD patients with increasing age at onset was observed. Choroidal anastomosis is a predictor of posterior hemorrhage. Hypertension is a risk factor for anterior hemorrhage in patients without extreme dilation of choroidal anastomosis.

Moyamoya disease and moyamoya syndrome in Ireland: patient demographics, mode of presentation and outcomes of EC-IC bypass surgery

BACKGROUND

There are no previously published reports regarding the epidemiology and characteristics of moyamoya disease or syndrome in Ireland.

AIMS

To examine patient demographics, mode of presentation and the outcomes of extracranial-intracranial bypass surgery in the treatment of moyamoya disease and syndrome in Ireland.

METHODS

All patients with moyamoya disease and syndrome referred to the National Neurosurgical Centre during January 2012-January 2019 were identified through a prospective database. Demographics, clinical presentation, radiological findings, surgical procedures, postoperative complications and any strokes during follow-up were recorded.

RESULTS

Twenty-one patients were identified. Sixteen underwent surgery. Median age at diagnosis was 19 years. Fifteen were female. Mode of presentation was ischaemic stroke in nine, haemodynamic TIAs in eight, haemorrhage in three and incidental in one. Sixteen patients had Moyamoya disease, whereas five patients had moyamoya syndrome. Surgery was performed on 19 hemispheres in 16 patients. The surgical procedures consisted of ten direct (STA-MCA) bypasses, five indirect bypasses and four multiple burr holes. Postoperative complications included ischaemic stroke in one patient and subdural haematoma in one patient. The median follow-up period in the surgical group was 52 months; there was one new stroke during this period. Two patients required further revascularisation following recurrent TIAs. One patient died during follow-up secondary to tumour progression associated with neurofibromatosis type 1.

CONCLUSIONS

Moyamoya is rare but occurs in Caucasians in Ireland. It most commonly presents with ischaemic symptoms. Surgical intervention in the form of direct and indirect bypass is an effective treatment in the majority of cases.

Difference in periventricular anastomosis in child and adult moyamoya disease: a vascular morphology study

BACKGROUNDS

Periventricular anastomosis (PA), which is a novel term for extended collateral vessels in moyamoya disease (MMD), is reportedly associated with a high risk of intracranial hemorrhage in adult patients. The present study aimed to clarify the similarities and the differences in the development of PA between three MMD groups, classified by age at the time of diagnosis and clinical phenotype.

METHODS

This study included 232 hemispheres of 132 patients with MMD who underwent surgical revascularization. The subjects were classified into child ischemic (CI) group, adult ischemic (AI) group, and adult hemorrhagic (AH) group. We evaluated the lenticulostriate (LSA), thalamic (THA), choroidal (ChA), anterior choroidal (AChA), and posterior choroidal (PChA) anastomosis as well as the posterior cerebral artery (PCA) involvement. The PA scores and the sums of each grade of LSA, THA, and ChA anastomosis were also calculated in all of the cases.

RESULTS

In a multiple comparison test, the PA scores (P < 0.01), LSA (P < 0.01), and ChA anastomosis (P = 0.013) were more prominent in the CI than in the AI group. The PA scores (P < 0.01) and LSA (P = 0.011), ChA (P < 0.01), AChA (P < 0.01), and PChA anastomosis (P = 0.016) were more prominent in the AH group than in the AI group. The CI and AH groups showed similar characteristics except for PCA involvement. After multivariate adjustments using the AI group as a reference group, the PA scores and the positive rates of LSA and ChA anastomosis remained significantly higher in the CI and AH groups.

CONCLUSION

The patterns of PA development in the CI and AH groups were similar in that they were more prominent than in the AI group. These findings may contribute to a better understanding of the progression of ischemic and hemorrhagic MMD.

Clinical and Radiological Outcomes After Revascularization of Hemorrhagic Moyamoya Disease

Objective: To evaluate clinical and radiological outcomes after revascularization of hemorrhagic moyamoya disease (MMD).

Materials and Methods: We retrospectively collected patients with hemorrhagic MMD who received revascularization from January 2011 to June 2018 at a high-volume stroke center. Rebleeding, ischemic stroke, modified Rankin Scale (mRS) and death after revascularization were used to evaluate long-term clinical outcome. Poor neurological outcome was defined as a mRS>2. The changes of original and revascularization collaterals were used to evaluate radiological outcome. The clinical and radiological outcomes between patients with different surgical revascularization were compared.

Results: A total of 312 patients (319 hemispheres) were recruited, including 133 hemispheres (41.7%) with indirect revascularization and 186 hemispheres (58.3%) with direct revascularization. In 308 hemispheres with clinical follow-up data, Postoperative rebleeding, ischemic stroke, poor neurological outcome and death occurred in 13.0% (40/308), 2.6% (8/308), 12.0% (37/308), and 6.2% (19/308) of the hemispheres, respectively. The rates of postoperative rebleeding (8.5 vs. 19.1%, P = 0.006) and poor neurological outcome (8.5 vs. 16.8%, P = 0.026) were lower in hemispheres with direct revascularization than those with indirect revascularization. However, there was no statistically significant difference in the rates of postoperative ischemic stroke (1.1 vs. 4.6%, P = 0.129) and death (4.5 vs. 8.4%, P = 0.162) between the two groups. Multivariate logistic regression analysis indicated that the risk of postoperative rebleeding was higher in those with untreated aneurysms, repetitive bleeding episodes, normal perfusion status, and indirect revascularization (P < 0.05). In 78 hemispheres with radiological follow-up data, the regression of moyamoya vessels, anterior choroidal artery (AchA), posterior communicating artery (PcomA) and aneurysms were present in 44.9, 47.4, 25.6, and 11.5% of the hemispheres, respectively. The regression of original collaterals and establishment of revascularization collaterals were more significant in hemispheres with direct revascularization than those with indirect revascularization (P < 0.05).

Conclusion: Direct revascularization may be superior to indirect revascularization for prevention of rebleeding and poor neurological outcome in adults with hemorrhagic MMD. The risk of postoperative rebleeding was higher in those with untreated aneurysms, repetitive bleeding episodes, normal perfusion status, and indirect revascularization. The regression of original collaterals and establishment of revascularization collaterals after revascularization were more significant in hemispheres with direct revascularization than those with indirect revascularization.

Cerebral Hemodynamic Changes After Revascularization in Patients With Hemorrhagic Moyamoya Disease

Objective: To explore the cerebral hemodynamic changes after revascularization in patients with hemorrhagic moyamoya disease (MMD).

Materials and Methods: We retrospectively included 57 hemorrhagic MMD patients in a high-volume stroke center from January 2016 to December 2018. All subjects were evaluated with whole-brain CT perfusion (CTP) before and after surgical revascularization. Absolute and relative CTP values in the regions of cortical middle cerebral artery territory (CMT) and deep brain area (DBA) of hemorrhagic hemispheres were measured. Differences between pre- and post-operative CTP values were assessed comprehensively. The patients were categorized into subgroups based on revascularization subtypes and postoperative CTP intervals.

Results: The relative cerebral blood volume (rCBV) in DBA and CMT significantly reduced in postoperative CTP (P < 0.05). The median and interquartile range of the proportion of rCBV decrease (rCBVc%) were 7.2% (2.3–13.2%). The rCBV reduction retained statistical significant in patients who received subtypes of revascularization, and in patients with variable intervals of follow-up (P < 0.05). There was no significant difference of rCBVc% between patients who received different revascularization and among patients with different postoperative CTP intervals (P > 0.05). The relative mean transit time (rMTT) and relative time to peak (rTTP) also showed downward trends, but without retainable statistical significance in stratified analysis. There was no significant change in relative cerebral blood flow (rCBF) (P > 0.05).

Conclusion: In patients with hemorrhagic MMD, the CBV appeared to decrease and be relatively stable in the chronic phase after revascularization, with varying degrees of MTT and TTP shortening. However, there was no significant change in CBF.

Angiographic study of the transdural collaterals at the anterior cranial fossa in patients with Moyamoya disease

Unlike its parietal, temporal, and occipital counterparts, the frontal lobe has a broad basal surface directly facing the anterior cranial fossa dura mater which could permit establishment of transdural collaterals (TDCs) with the frontal lobe. Studies on the TDCs from the anterior cranial fossa in moyamoya disease (MMD) are scarce and inadequately investigated. A retrospective study of 100 hemispheres in 50 patients who were diagnosed with MMD by catheter angiography between January 2015 and June 2019 was performed in our institution. TDCs through the anterior ethmoid artery (AEA) or posterior ethmoid artery (PEA) were divided into 3 types respectively based on their respective angioarchitecture. Furthermore, we also studied TDCs to the temporal, parietal, and occipital lobes and collaterals from the posterior circulation to the territory of the anterior cerebral artery. TDCs through the AEA and PEA were identified in 89 (89/100, 89%) and 73 (73/100, 73%) of the hemispheres. The vascularization state of the frontal lobe was good in 89 (89/100, 89%) hemispheres. Rete mirabile and TDCs through the PEA were statistically different among patients with different Suzuki stages. No statistical difference was noted in TDCs through the AEA, frontal TDCs from other sources, and the vascularization state of the frontal lobe with regard to different Suzuki stages. TDCs through the AEA and PEA at the anterior cranial fossa play a very important role in compensating the ischemic frontal lobe. The frontal lobe could be well compensated in most of the patients with TDCs at the anterior cranial fossa.

Circulating miRNome profiling in Moyamoya disease-discordant monozygotic twins and endothelial microRNA expression analysis using iPS cell line

Background

Moyamoya disease (MMD) is characterized by progressive stenosis of intracranial arteries in the circle of Willis with unknown etiology even after the identification of a Moyamoya susceptible gene, RNF213. Recently, differences in epigenetic regulations have been investigated by a case-control study in MMD. Here, we employed a disease discordant monozygotic twin-based study design to unmask potential confounders.

Methods

Circulating genome-wide microRNA (miRNome) profiling was performed in MMD-discordant monozygotic twins, non-twin-MMD patients, and non-MMD healthy volunteers by microarray followed by qPCRvalidation, using blood samples. Differential plasma-microRNAs were further quantified in endothelial cells differentiated from iPS cell lines (iPSECs) derived from another independent non-twin cohort. Lastly, their target gene expression in the iPSECs was analyzed.

Results

Microarray detected 309 plasma-microRNAs in MMD-discordant monozygotic twins that were also detected in the non-twin cohort. Principal component analysis of the plasma-microRNA expression level demonstrated distinct 2 groups separated by MMD and healthy control in the twin- and non-twin cohorts. Of these, differential upregulations of hsa-miR-6722-3p/− 328-3p were validated in the plasma of MMD (absolute log2 expression fold change (logFC) > 0.26 for the twin cohort; absolute logFC > 0.26, p < 0.05, and q < 0.15 for the non-twin cohort). In MMD derived iPSECs, hsa-miR-6722-3p/− 328-3p showed a trend of up-regulation with a 3.0- or higher expression fold change. Bioinformatics analysis revealed that 41 target genes of miR-6722-3p/− 328-3p were significantly down-regulated in MMD derived iPSECs and were involved in STAT3, IGF-1-, and PTEN-signaling, suggesting a potential microRNA-gene expression interaction between circulating plasma and endothelial cells.

Conclusions

Our MMD-discordant monozygotic twin-based study confirmed a novel circulating microRNA signature in MMD as a potential diagnostic biomarker minimally confounded by genetic heterogeneity. The novel circulating microRNA signature can contribute for the future functional microRNA analysis to find new diagnostic and therapeutic target of MMD.

Electronic supplementary material

The online version of this article (10.1186/s12920-018-0385-3) contains supplementary material, which is available to authorized users.