Moyamoya: defining current knowledge gaps

Long-term stroke risk in Moyamoya disease

BACKGROUND

Moyamoya disease (MMD) is considered a progressive disease with an ongoing risk of recurrent stroke. However, there is a lack of long-term observational data to quantify the extent of the stroke risk.

METHODS

This study aimed to provide insight into the long-term stroke risk in MMD and explore possible risk factors for stroke. Records from all patients diagnosed with MMD in 13 clinical departments from 6 different Danish hospitals between 1994 and 2017 were retrospectively reviewed until 2021.

RESULTS

The cohort comprised 50 patients (33 females and 17 males). Patients were followed up for a median of 9.4 years, with more than 10 years of follow-up for 24 patients. Ten patients had 11 new stroke events-6 ischemic strokes and 5 brain hemorrhages. Events occurred at a median of 7 years and up to 25 years after diagnosis. The overall Kaplan-Meier 5-year stroke risk was 10%. Patients with bypass performed had significantly fewer events than conservatively treated patients (HR 0.25, 95% confidence interval (CI) 0.07-0.91, p < 0.05). All but one event occurred in females, a difference that reached statistical significance.

CONCLUSIONS

The study provides data on the extent of the risk of recurrent stroke in MMD. Bypass surgery patients had fewer stroke events than those treated conservatively. There was a trend toward a higher stroke risk in females.

DATA ACCESS STATEMENT

The data supporting this study's findings are available from the corresponding author upon reasonable request.

Disease specific urinary biomarkers in the central nervous system

Urinary biomarkers can diagnose and monitor pathophysiologic conditions in the central nervous system (CNS). However, focus is often on single diseases, with limited data on discriminatory capability of this approach in a general setting. Here, we demonstrate that different classes of CNS disease exhibit distinct biomarker patterns, evidence of disease-specific "fingerprinting." Urine from 218 patients with pathology-confirmed tumors or cerebrovascular disease, controls (n = 33) were collected. ELISA and/or bead-based multiplexing quantified levels of 21 putative urinary biomarkers. Analysis identified biomarkers capable of distinguishing each disease from controls and other diseases. Mann-Whitney U tests identified biomarkers with differential expression between disease types and controls (P ≤ 0.001). Subsequent receiver-operating characteristic (ROC) analyses revealed distinguishing biomarkers with high sensitivity and specificity. Areas under the curve (AUCs) ranged 0.8563-1.000 (P values ≤ 0.0003), sensitivities ranged 80.00-100.00%, and specificities ranged 80.95-100.00%. These data demonstrate proof-of-principle evidence that disease-specific urinary biomarker signatures exist. In contrast to non-specific responses to ischemia or injury, these results suggest that urinary biomarkers accurately reflect unique biological processes distinct to different diseases. This work can be used to generate disease-specific panels for enhancing diagnosis, assisting less-invasive follow-up and herald utility by revealing putative disease-specific therapeutic targets.

Physiological and pathophysiological mechanisms of the molecular and cellular biology of angiogenesis and inflammation in moyamoya angiopathy and related vascular diseases

Rationale

The etiology and pathophysiological mechanisms of moyamoya angiopathy (MMA) remain largely unknown. MMA is a progressive, occlusive cerebrovascular disorder characterized by recurrent ischemic and hemorrhagic strokes; with compensatory formation of an abnormal network of perforating blood vessels that creates a collateral circulation; and by aberrant angiogenesis at the base of the brain. Imbalance of angiogenic and vasculogenic mechanisms has been proposed as a potential cause of MMA. Moyamoya vessels suggest that aberrant angiogenic, arteriogenic, and vasculogenic processes may be involved in the pathophysiology of MMA. Circulating endothelial progenitor cells have been hypothesized to contribute to vascular remodeling in MMA. MMA is associated with increased expression of angiogenic factors and proinflammatory molecules. Systemic inflammation may be related to MMA pathogenesis.

Objective

This literature review describes the molecular mechanisms associated with cerebrovascular dysfunction, aberrant angiogenesis, and inflammation in MMA and related cerebrovascular diseases along with treatment strategies and future research perspectives.

Methods and results

References were identified through a systematic computerized search of the medical literature from January 1, 1983, through July 29, 2022, using the PubMed, EMBASE, BIOSIS Previews, CNKI, ISI web of science, and Medline databases and various combinations of the keywords "moyamoya," "angiogenesis," "anastomotic network," "molecular mechanism," "physiology," "pathophysiology," "pathogenesis," "biomarker," "genetics," "signaling pathway," "blood-brain barrier," "endothelial progenitor cells," "endothelial function," "inflammation," "intracranial hemorrhage," and "stroke." Relevant articles and supplemental basic science articles almost exclusively published in English were included. Review of the reference lists of relevant publications for additional sources resulted in 350 publications which met the study inclusion criteria. Detection of growth factors, chemokines, and cytokines in MMA patients suggests the hypothesis of aberrant angiogenesis being involved in MMA pathogenesis. It remains to be ascertained whether these findings are consequences of MMA or are etiological factors of MMA.

Conclusions

MMA is a heterogeneous disorder, comprising various genotypes and phenotypes, with a complex pathophysiology. Additional research may advance our understanding of the pathophysiology involved in aberrant angiogenesis, arterial stenosis, and the formation of moyamoya collaterals and anastomotic networks. Future research will benefit from researching molecular pathophysiologic mechanisms and the correlation of clinical and basic research results.

Intracranial Vascular Abnormalities in Children

Intracranial vascular abnormalities rarely are encountered in primary care. Many of the pathologies are occult and prognosis varies widely between inconsequential variants of anatomy to acutely life-threatening conditions. Consequently, there often is a great deal of anxiety associated with any potential diagnosis. This article reviews anatomic intracranial vascular lesions, including vascular malformations (arteriovenous malformations/arteriovenous fistulae and cavernous malformations), structural arteriopathies (aneurysms and moyamoya), and common developmental anomalies of the vasculature. The focus includes a general overview of anatomy, pathology, epidemiology, and key aspects of evaluation for the primary care provider and a review of common questions encountered in practice.

Silent Moyamoya disease - A rare case report

Moyamoya is a rare cerebrovascular disorder marked by chronic, gradual blockage of the circle of Willis arteries, leading to characteristic collateral vessels, specifically cerebral angiography. The disease can develop in children and adults, although there are different clinical characteristics. Moyamoya disease occurs mainly in Japanese people but has been reported in all races of varying age distributions and clinical features. As a reason, Moyamoya disease has been under-recognized as a cause of hemorrhagic and ischemic strokes in Western nations. There is no proven solution at this time, and there is debate over current care methods. The authors identify a case of a 40-year-old male with a small subcutaneous nevus-like mass in his left orbit who was diagnosed with Moyamoya disease.

Non-invasive Urinary Biomarkers in Moyamoya Disease

Introduction: A major difficulty in treating moyamoya disease is the lack of effective methods to detect novel or progressive disease prior to the onset of disabling stroke. More importantly, a tool to better stratify operative candidates and quantify response to therapy could substantively complement existing methods. Here, we present proof-of-principle data supporting the use of urinary biomarkers as diagnostic adjuncts in pediatric moyamoya patients.

Methods: Urine and cerebrospinal fluid specimens were collected from pediatric patients with moyamoya disease and a cohort of age and sex-matched control patients. Clinical and radiographic data were paired with measurements of a previously validated panel of angiogenic proteins quantified by ELISA. Results were compared to age and sex-matched controls and subjected to statistical analyses.

Results: Evaluation of a specific panel of urinary and cerebrospinal fluid biomarkers by ELISA demonstrated significant elevations of angiogenic proteins in samples from moyamoya patients compared to matched controls. ROC curves for individual urinary biomarkers, including MMP-2, MMP-9, MMP-9/NGAL, and VEGF, showed excellent discrimination. The optimal urinary biomarker was MMP-2, providing a sensitivity of 88%, specificity of 100%, and overall accuracy of 91%. Biomarker levels changed in response to therapy and correlated with radiographic evidence of revascularization.

Conclusions: We report, for the first time, identification of a panel of urinary biomarkers that predicts the presence of moyamoya disease. These biomarkers correlate with presence of disease and can be tracked from the central nervous system to urine. These data support the hypothesis that urinary proteins are useful predictors of the presence of moyamoya disease and may provide a basis for a novel, non-invasive method to identify new disease and monitor known patients following treatment.

Moyamoya as a Cause of Altered Mental Status in the Emergency Department: A Case Report

Introduction

This case reviews a patient with moyamoya disease, a rare cause of altered mental status. It highlights the importance of maintaining clinical suspicion for uncommon causes of common presentations.

Case Report

A 64-year-old male presented with seizures and persistent altered mental status. Computed tomography demonstrated findings consistent with bilateral ischemia. Cerebral angiography was performed with no thrombus identified but moyamoya disease present.

Conclusion

Although rare, moyamoya should be considered as a potential cause of patients presenting with altered mental status. The case presented also highlights the importance of avoiding common diagnostic biases.

Transition to Adulthood for Pediatric Moyamoya Patients

Moyamoya is a progressive arteriopathy of the intracranial vasculature, predominantly affecting the terminal branches of the internal carotid artery. Treatment is predicated on surgical revascularization to reduce the risk of stroke. For patients diagnosed and treated as children, it is important to recognize the long-term implications of the disease, for example, that moyamoya is treatable, but not curable. Pediatric moyamoya patients face unique challenges as they transition to adulthood as a consequence of the chronic nature of this disorder. Successful long-term care requires a strategy that incorporates ongoing longitudinal disease monitoring, coordination of care between physician teams, and anticipation of socioeconomic factors that change over time. This article provides an approach to transition care to adult caregivers for pediatric moyamoya patients with a specific focus on the three key stakeholders in the process: the neurosurgeon, the primary care physician, and the individual patient.

Clinical outcomes after revascularization for pediatric moyamoya disease and syndrome: A single-center series

Moyamoya is a progressive cerebrovascular arteriopathy that affects children of any age. The goal of this study was to determine imaging and clinical outcomes as well as complication rates in a pediatric cohort undergoing either a combined direct/indirect or indirect-only revascularization approach. Patients with moyamoya disease or syndrome ≤ 18 years of age at the time of initial surgery were identified, and clinical data were collected retrospectively. Over a 12-year period, 26 patients underwent revascularization procedures on 49 hemispheres with a median follow-up of 2.6 years from surgery. Median age at surgery was 7.3 years (range 1.4-18.0 years). Thirty-three hemispheres (67.3%) underwent combined revascularization with a direct bypass and encephalomyosynangiosis, and sixteen hemispheres (32.7%) underwent indirect-only revascularization. The rate of 30-day perioperative complication was 10.2%, and the rate of postoperative clinical stroke by end of follow-up was 10.2% by hemisphere. There was a 5.7% rate of intraoperative bypass failure requiring conversion to an indirect revascularization approach. On follow-up imaging, 96.9% of direct bypasses remained patent. On multivariate analysis, higher preoperative Pediatric Stroke Outcome Measure (PSOM) scores were associated with lower rates of good clinical outcome on follow-up (unit OR 0.03; p = 0.03). Patients with age < 5.4 years had lower rates of good clinical outcome on follow-up. In this North American cohort, both combined direct/indirect and indirect only revascularization techniques were feasible. However, younger children < 5.4 years of age have worse outcomes than older children, similar to east Asian cohorts.

PHACTR1 is associated with disease progression in Chinese Moyamoya disease

Moyamoya disease (MMD) is a progressive stenosis at the terminal portion of internal carotid artery and frequently occurs in East Asian countries. The etiology of MMD is still largely unknown. We performed a case-control design with whole-exome sequencing analysis on 31 sporadic MMD patients and 10 normal controls with matched age and gender. Patients clinically diagnosed with MMD was determined by digital subtraction angiography (DSA). Twelve predisposing mutations on seven genes associated with the sporadic MMD patients of Chinese ancestry (CCER2, HLA-DRB1, NSD-1, PDGFRB, PHACTR1, POGLUT1, and RNF213) were identified, of which eight single nucleotide variants (SNVs) were deleterious with CADD PHRED scaled score > 15. Sanger sequencing of nine cases with disease progression and 22 stable MMD cases validated that SNV (c.13185159G>T, p.V265L) on PHACTR1 was highly associated with the disease progression of MMD. Finally, we knocked down the expression of PHACTR1 by transfection with siRNA and measured the cell survival of human coronary artery endothelial cell (HCAEC) cells. PHACTR1 silence reduced the cell survival of HCAEC cells under serum starvation cultural condition. Together, these data identify novel predisposing mutations associated with MMD and reveal a requirement for PHACTR1 in mediating cell survival of endothelial cells.

Vascular complications in pediatric craniopharyngioma patients: a case-based update

PURPOSE

Craniopharyngiomas remain a challenging entity for neurosurgeons because of their deep-seated, midline location, and intimate relationship with critical neurovascular structures. With high long-term survival rates, patients with craniopharyngioma are likely to experience significant late morbidity related to both disease and therapy.

METHOD AND RESULTS

In this paper, we present two cases of late vascular complications after multi-modal treatment of craniopharyngioma.

CONCLUSION

Available data suggests that pediatric patients with craniopharyngioma represent a particularly vulnerable group.

Characteristics of Moyamoya Disease Based on National Registry Data in Japan

Background and Purpose—

A public registration system for intractable diseases was started in Japan in 1972 to investigate the etiology and pathogenesis of intractable diseases while reducing out-of-pocket medical expenses on patients. The goal of this study was to investigate the epidemiology and clinical characteristics of Moyamoya disease using data from applications submitted to this system between 2004 and 2008.

Methods—

In addition to demographic factors such as onset age and family history, we evaluated clinical presentation type, imaging findings, clinical symptoms, and functioning in activities of daily living (ADL).

Results—

Of 3859 cases for which applications were submitted, 2545 were confirmed to meet the diagnostic criteria after data cleansing. Onset age showed a bimodal distribution, and Moyamoya disease had a higher incidence in women than in men. The presence of occlusion and infarction in the proximal region of the anterior cerebral artery was more frequent in pediatric cases than adult cases. Our findings also indicated that 23% of patients required assistance with ADL. Cerebral infarction (odds ratio [OR], 12.5; 95% CI, 3.55–44.66), seizure (OR, 7.44; 95% CI, 1.29–42.96), and sensory disorders (OR, 5.23; 95% CI, 1.15–23.75) were identified as significant predictors of impaired ADL in pediatric cases 3 years after the initial application. Moderate ADL function (OR, 11.59; 95% CI, 5.29–25.39) and intellectual disabilities (OR, 4.38; 95% CI, 1.58–12.17) at the time of the application were identified as significant prognostic factors in adults.

Conclusions—

The results of this study indicated that characteristics of Moyamoya disease such as onset type, symptoms, and imaging abnormalities differ with onset age. Prognostic analyses suggested that pediatric cases with good ADL but with infarct type onset, seizure, or sensory disorders might have a subsequent decline in ADL.

Predictors of clinical or cerebral lesion progression in adult moyamoya angiopathy

OBJECTIVE

To identify independent predictors of clinical or cerebral lesion progression in a large sample of adult patients with moyamoya angiopathy (MMA) prior to decisions regarding revascularization surgery.

METHODS

Ninety participants (median age, 37.5 years) were assessed at baseline and followed for a median time of 42.8 months. Incident ischemic and hemorrhagic strokes, death, as well as any incident ischemic and hemorrhagic lesions on MRI were recorded. Multiple demographic, clinical, and cerebral imaging measures at baseline were considered as potential predictors of clinical or cerebral tissue change at follow-up. Data were analyzed based on the Andersen-Gill counting process model, followed by internal validation of the prediction model.

RESULTS

Among multiple potential predictive measures considered in the analysis, Asian origin, a history of TIAs, and a reduction in hemodynamic reserve, as detected by imaging, were found to be significantly associated with an increased risk of combined clinical and imaging events. While the model estimated the risk of clinical or cerebral lesion progression to be approximately 0.5% per year when none of these factors was present, this risk exceeded 20% per year when all factors were present.

CONCLUSION

A simple combination of demographic, clinical, and cerebral perfusion imaging measures may aid in predicting the risk of incident stroke and cerebral lesion progression in adult patients with MMA. These results may help to improve therapeutic decisions and aid in the design of future trials in adults with this rare condition.

Preliminary application of CT perfusion source images for evaluating regional collateral circulation in unilateral Moyamoya disease

Background

Collateral flow is associated with clinical outcomes for patients with Moyamoya disease and served as a parameter for patient selection of therapeutic strategies. Therefore, we explored whether a noninvasive imaging modality, computed tomography perfusion (CTP) source images (CTP-Sis), could be used to identify the presence and intensity of collateral flow using digital subtraction angiography (DSA) as a gold standard for collateral flow.

Methods

CTP-Sis and DSA were performed for 24 patients with unilateral Moyamoya disease. A collateral grading system was developed based on arterial and venous phase CTP-Sis, imitating the DSA score system. Two neuroradiologists scored the DSA images using a collateral grading scale for the regions of interest corresponding to the Alberta Stroke Program Early computed tomography Score (ASPECTS) methodology. Another two neuroradiologists scored CTP-Sis in a similar manner. Agreement between the CTP-Sis and DSA consensus scores was determined, including kappa statistics.

Results

The agreement between the CTP-Sis and DSA consensus readings was moderate to strong, with a weighted kappa value of 0.768 [95% confidence interval (CI), 0.703-0.832], but there was a better agreement for readers of CTP-Sis, as compared with those of DSA. The sensitivity and specificity for identifying collaterals with CTP-Sis were 0.714 (95% CI, 0.578-0.851) and 0.995 (95% CI, 0.985-1.000), respectively.

Conclusions

CTP-Sis could help identify in a noninvasive manner the presence and intensity of collateral flow in patients with unilateral Moyamoya disease using DSA as a gold standard. Further study with a large number of cases is warranted. Further application of this method to other cerebrovascular diseases including acute ischemic stroke can also be warranted.

GEN-O-MA project: an Italian network studying clinical course and pathogenic pathways of moyamoya disease-study protocol and preliminary results

BACKGROUND

GENetics of mOyaMoyA (GEN-O-MA) project is a multicenter observational study implemented in Italy aimed at creating a network of centers involved in moyamoya angiopathy (MA) care and research and at collecting a large series and bio-repository of MA patients, finally aimed at describing the disease phenotype and clinical course as well as at identifying biological or cellular markers for disease progression. The present paper resumes the most important study methodological issues and preliminary results.

METHODS

Nineteen centers are participating to the study. Patients with both bilateral and unilateral radiologically defined MA are included in the study. For each patient, detailed demographic and clinical as well as neuroimaging data are being collected. When available, biological samples (blood, DNA, CSF, middle cerebral artery samples) are being also collected for biological and cellular studies.

RESULTS

Ninety-eight patients (age of onset mean ± SD 35.5 ± 19.6 years; 68.4% females) have been collected so far. 65.3% of patients presented ischemic (50%) and haemorrhagic (15.3%) stroke. A higher female predominance concomitantly with a similar age of onset and clinical features to what was reported in previous studies on Western patients has been confirmed.

CONCLUSION

An accurate and detailed clinical and neuroimaging classification represents the best strategy to provide the characterization of the disease phenotype and clinical course. The collection of a large number of biological samples will permit the identification of biological markers and genetic factors associated with the disease susceptibility in Italy.

Juvenile Moyamoya and Craniosynostosis in a Child with Deletion 1p32p31: Expanding the Clinical Spectrum of 1p32p31 Deletion Syndrome and a Review of the Literature

Moyamoya angiopathy (MA) is a rare cerebrovascular disorder characterised by the progressive occlusion of the internal carotid artery. Its aetiology is uncertain, but a genetic background seems likely, given the high MA familial rate. To investigate the aetiology of craniosynostosis and juvenile moyamoya in a 14-year-old male patient, we performed an array-comparative genomic hybridisation revealing a de novo interstitial deletion of 8.5 Mb in chromosome region 1p32p31. The deletion involved 34 protein coding genes, including NF1A, whose haploinsufficiency is indicated as being mainly responsible for the 1p32-p31 chromosome deletion syndrome phenotype (OMIM 613735). Our patient also has a deleted FOXD3 of the FOX gene family of transcription factors, which plays an important role in neural crest cell growth and differentiation. As the murine FOXD3^−/− model shows craniofacial anomalies and abnormal common carotid artery morphology, it can be hypothesised that FOXD3 is involved in the pathogenesis of the craniofacial and vascular defects observed in our patient. In support of our assumption, we found in the literature another patient with a syndromic form of MA who had a deletion involving another FOX gene (FOXC1). In addition to describing the clinical history of our patient, we have reviewed all of the available literature concerning other patients with a 1p32p31 deletion, including cases from the Decipher database, and we have also reviewed the genetic disorders associated with MA, which is a useful guide for the diagnosis of syndromic form of MA.

Incidence, clinical features, and treatment of familial moyamoya in pediatric patients: a single-institution series

OBJECTIVE Limited data exist on familial moyamoya in children. The purpose of this study was to characterize presentation and outcomes of pediatric moyamoya patients who have relatives diagnosed with moyamoya. METHODS The authors performed a single-institution retrospective analysis of a case series including all surgically treated children with moyamoya with first- or second-degree relatives with moyamoya. Clinical and radiographic characteristics were analyzed, along with surgical outcomes. RESULTS A total of 537 patients underwent surgery for moyamoya during the study period. Eighteen of those patients (3.4% of the total series) had moyamoya and a family history of moyamoya and were included in this study. Of these 18 patients, 14 were non-twin siblings, and the remaining 4 represented 2 pairs of identical (affected) twins. The presentation was predominantly ischemic (72%), but 4 patients (33%) were asymptomatic when they were found to have moyamoya. Bilateral disease was present in 13 patients (72%). Radiographic stroke prevalence (67%), Suzuki grade (3.3), and angiographic findings were comparable to findings in nonfamilial moyamoya patients. Thirty revascularization procedures were performed, with a 3.3% operative stroke rate per hemisphere and no new strokes in an average follow-up period of 4.5 years. CONCLUSIONS In a North American surgical series, familial moyamoya existed in 3.4% of cases, and was distinguished by manifesting in a broad range of ethnic groups, with a higher proportion of male patients and increased rates of asymptomatic and unilateral disease in comparison to nonfamilial moyamoya. Screening indications remain controversial and the current data are used to suggest guidelines. Surgical therapy is warranted, effective, and durable in these patients, but patients should be carefully selected.