Moyamoya disease: a review of the literature

Complications associated with combined direct and indirect bypass in Moyamoya Disease: A meta-analysis

Bypass revascularization helps prevent complications in Moyamoya Disease (MMD). To systematically review complications associated with combined direct and indirect (CB) bypass in MMD and analyze differences between the adult and pediatric populations. A systematic literature review was conducted per PRISMA guidelines. PUBMED, Cochrane Library, Web of Science, and CINAHL, were queried from January 1980 to March 2022. Complications were defined as any event in the immediate post-surgical period of a minimum 3 months follow-up. Exclusion criteria included lack of surgical complication reports, non-English articles, and CB unspecified or reported separately. 18 final studies were included of 1580 procured. 1151 patients (per study range = 10-150, mean = 63.9) were analyzed. 9 (50.0%) studies included pediatric patients. There were 32 total hemorrhagic, 74 total ischemic and 16 total seizure complications, resulting in a rate of 0.04 (95% CI 0.03, 0.06), 0.7 (95% CI 0.04, 0.10) and 0.03 (95% CI 0.02, 0.05), respectively. The rate of hemorrhagic complications in the pediatric showed no significant difference from the adult subgroup (0.03 (95% CI 0.01-0.08) vs. 0.06 (95% CI 0.04-0.10, p = 0.19), such as the rate of ischemic complications (0.12 (95% CI 0.07-0.23) vs. 0.09 (95% CI 0.05-0.14, p = 0.40). Ischemia is the most common complication in CB for MMD. Pediatric patients had similar hemorrhagic and ischemic complication rates compared to adults.

Clinical significance of asymmetric venous vasculature on minimum-intensity projection in patients with moyamoya disease

This study analyzed the clinical significance and characteristics of asymmetric venous blood flow in patients with Moyamoya disease (MMD) using minimum intensity projection (minIP) susceptibility-weighted imaging. The minIP views of 30 patients diagnosed with MMD were retrospectively analyzed using clinical features, brain magnetic resonance angiography, electroencephalography, and brain single-photon emission computed tomography (SPECT). Simultaneously, differences between patients with acute cerebral infarction and non-MMD causes were analyzed. Twelve (40.0%) of the 30 patients had asymmetrical venous flow, which is usually seen in patients with acute cerebral infarction (P = .146). They also had significantly higher Suzuki stages than symmetric patients (P = .014), with five (41.7%) and three (25.0%) of them in stages 4 and 5, respectively. When the Suzuki stages of both hemispheres were different, more veins were found in the stenotic hemisphere (88.9%). Brain SPECT showed more severe hypoperfusion on the side with prominent vascularity in the minIP view (100.0%). Additionally, asymmetric blood flow was observed in 66.7% of the patients with cerebral infarction caused by MMD, whereas only 11.1% of the children with cerebral infarction caused by non-MMD had asymmetry (P = .005). Patients with MMD showed asymmetric hypointensity of the cortical veins with a minIP appearance. The venous structure showed greater signal loss on SWI and was more prominent in the hemisphere where stenosis was advanced or infarction occurred in other examinations. Cerebral infarction in patients with MMD tended to occur with asymmetrically prominent venous patterns with damaged areas in minIP images, which had distinct characteristics from those of patients without MMD.

A Recipe for Delirium: Community-Acquired Pneumonia and Sickle Cell Anemia With Moyamoya Disease

Moyamoya disease (MMD) is a rare, progressive cerebrovascular disorder that occurs when the major arteries supplying the brain become narrowed or obstructed. Because of this, small and delicate collateral vessels develop to compensate for the decrease in blood flow. Unfortunately, these vessels are insufficient to meet the brain's metabolic demands. Though initially described in Japan, MMD occurs in a variety of ethnicities around the world. The clinical manifestations of the disease can be devastating, with patients often presenting with symptoms of a stroke or transient ischemic attack. The long history of insults and chronic changes to the brain makes these individuals susceptible to alterations in their mental status. We describe a case of a young African American female with a history of sickle cell anemia (SCA) and undiagnosed MMD who presented to the emergency department with community-acquired pneumonia (CAP). In addition to her medical derangements, she also presented with paranoia, delusional guilt, and refusal to speak.

Preoperative brain connectome predicts postoperative changes in processing speed in moyamoya disease

Moyamoya disease is a rare cerebrovascular disorder associated with cognitive dysfunction. It is usually treated by surgical revascularization, but research on the neurocognitive outcomes of revascularization surgery is controversial. Given that neurocognitive impairment could affect the daily activities of patients with moyamoya disease, early detection of postoperative neurocognitive outcomes has the potential to improve patient management. In this study, we applied a well-established connectome-based predictive modelling approach to develop machine learning models that used preoperative resting-state functional connectivity to predict postoperative changes in processing speed in patients with moyamoya disease. Twelve adult patients with moyamoya disease (age range: 23–49 years; female/male: 9/3) were recruited prior to surgery and underwent follow-up at 1 and 6 months after surgery. Twenty healthy controls (age range: 24–54 years; female/male: 14/6) were recruited and completed the behavioural test at baseline, 1-month follow-up and 6-month follow-up. Behavioural results indicated that the behavioural changes in processing speed at 1 and 6 months after surgery compared with baseline were not significant. Importantly, we showed that preoperative resting-state functional connectivity significantly predicted postoperative changes in processing speed at 1 month after surgery (negative network: ρ = 0.63, P_corr = 0.017) and 6 months after surgery (positive network: ρ = 0.62, P_corr = 0.010; negative network: ρ = 0.55, P_corr = 0.010). We also identified cerebro-cerebellar and cortico-subcortical connectivities that were consistently associated with processing speed. The brain regions identified from our predictive models are not only consistent with previous studies but also extend previous findings by revealing their potential roles in postoperative neurocognitive functions in patients with moyamoya disease. Taken together, our findings provide preliminary evidence that preoperative resting-state functional connectivity might predict the post-surgical longitudinal neurocognitive changes in patients with moyamoya disease. Given that processing speed is a crucial cognitive ability supporting higher neurocognitive functions, this study’s findings offer important insight into the clinical management of patients with moyamoya disease.

Early manifestation of Moyamoya syndrome in a 2-year-old child with Down syndrome

Moyamoya is a rare occlusive cerebrovascular disease characterized by progressive stenosis of the terminal portion of the internal carotid artery and the circle of Willis. Over time, collateral arteries are usually formed at the basal ganglia, the so-called Moyamoya vessels. The exact cause of Moyamoya disease is unknown, while Moyamoya syndrome refers to Moyamoya-like vasculopathy due to autoimmune diseases, neurofibromatosis type I, sickle cell disease, radiation, or rarely Down syndrome. Down syndrome is one of the most common genetic conditions, characterized by typical physical traits, associated with intellectual disability and a heterogeneous group of structural defects that may vulnerable the patient for the development of Moyamoya syndrome. The reported case is an unusual case of a 2-year-old boy with Down syndrome who presented to the hospital with seizures and right-side weakness. Brain MRI shows acute as well as old lacunar infarctions in both cerebral hemispheres. Catheter angiography of the patient demonstrates severe stenosis and occlusion of the large vessels of the circle of Willis, predominantly on the right side. The collateral vessels with the typical pattern of “puff of smoke” were also depicted in the right basal ganglia, which is a characteristic imaging finding for Moyamoya. The patient was managed conservatively and eventually discharged with a minimal improvement of the right-sided weakness. This case report is noteworthy because of the rarity of Moyamoya syndrome as a cause of a stroke as well as its possible association with Down syndrome.

The Moyamoya Health Behavior Scale for Adolescent Patients: Measurement Tool Development and Psychometric Evaluation

Clinical practitioners treating moyamoya disease recognize the need for a systematic approach to better manage the disease in adolescent patients with the disease. Methods: This study aimed to develop and evaluate the validity and reliability of a disease scale which measures the health-related behaviors of adolescents with moyamoya disease. Results: The final 12-item Moyamoya-HB Scale for adolescents was categorized by three sub-domains: implementation of treatment for moyamoya disease (four items); health promoting behavior for moyamoya disease (four items); and health coping behavior for moyamoya disease (four items). Overall, these factors explained 68.97% of the total variance. The results of the confirmative factor analysis supported the construct, convergent and discriminant validity of the three sub-domains. The Moyamoya-HB Scale for adolescents also demonstrated a concurrent validity with the Korean Adolescents’ Health Behaviors Tool (r = 0.59, p < 0.001). Reliability analysis showed an acceptable-to-high Cronbach’s alpha of 0.865 in total, and the subscales ranged from 0.800 to 0.841. Conclusions: Initial findings support the Moyamoya-HB Scale as a reliable and valid measure of health behaviors in adolescents with moyamoya disease.

Xq28 copy number gain causing moyamoya disease and a novel moyamoya syndrome

BACKGROUND

The molecular anomalies causing moyamoya disease (MMD) and moyamoya syndromes (MMS) are unknown in most patients.

OBJECTIVE

This study aimed to identify de novo candidate copy number variants (CNVs) in patients with moyamoya.

METHODS

Rare de novo CNVs screening was performed in 13 moyamoya angiopathy trios using whole exome sequencing (WES) reads depth data and whole genome high density SNP array data. WES and SNP array data from an additional cohort of 115 unrelated moyamoya probands were used to search for recurrence of these rare de novo CNVs.

RESULTS

Two de novo CNVs were identified in two unrelated probands by both methods and confirmed by qPCR. One of these CNVs, located on Xq28, was detected in two additional families. This interstitial Xq28 CNV gain is absent from curated gold standard database of control genomic variants and gnomAD databases. The critical region contains five genes, including MAMLD1, a major NOTCH coactivator. Typical MMD was observed in the two families with a duplication, whereas in the triplicated patients of the third family, a novel MMS associating moyamoya and various systemic venous anomalies was evidenced.

CONCLUSION

The recurrence of this novel Xq28 CNV, its de novo occurrence in one patient and its familial segregation with the affected phenotype in two additional families strongly suggest that it is pathogenic. In addition to genetic counselling application, its association with pulmonary hypertension is of major importance for clinical care. These data also provide new insights into the genomic architecture of this emblematic, non-atherosclerotic, large vessel disease.

Outpatient Interventions That May Enhance the Care of a Patient with Co-existing Moyamoya and Down Syndromes

Moyamoya vasculopathy is a condition of chronic, progressive occlusion of the distal internal carotid arteries and the Circle of Willis. The resultant ischemia produces compensatory angiogenesis and the growth of a network of collateral blood vessels, which on angiography resemble a “puff of smoke” or “moyamoya” in Japanese. The objective of this case report is to describe the clinical course of a patient with Down and moyamoya syndromes and to enlighten clinicians about strategies that can be taken to enhance the care of similar patients.

A 55-year-old African American female presented to the hospital with complaints of headache, vision loss, dysarthria, and ataxia. She had a past medical history of Down syndrome and a stroke with residual lower extremity weakness. At her baseline, the patient was able to perform her activities of daily living but required assistance with independent activities of daily living. Computed tomography of the brain showed hypodense areas at the right occipital, temporal, and parietal lobes. Computed tomography angiography of the head and neck identified occlusion bilaterally at the supraclinoid internal carotid arteries and right posterior cerebral artery; there was collateral arterial flow within the right middle cerebral and anterior cerebral arteries that was consistent with moyamoya vasculopathy.

Patients with Down syndrome experience premature accelerated aging and suffer from comorbidities seen in geriatric patients by the time they reach their 40s. Patients with moyamoya vasculopathy experience neurocognitive and neuropsychiatric deficits that correspond to the regions of the brain that are affected. This patient with Down and moyamoya syndromes had impaired neurocognitive and functional status, and we believe that she would have benefited from receiving a comprehensive geriatric assessment and neuropsychiatric testing.