Late Cerebrovascular Events and Social Outcome after Adolescence: Long-term Outcome of Pediatric Moyamoya Disease

Nomogram for Predicting Long-term Outcomes of Encephaloduroarteriosynangiosis in Toddlers with Moyamoya Disease: a Longitudinal and Cross-sectional Study

We investigated the long-term outcomes of encephaloduroarteriosynangiosis (EDAS) for stroke prevention in toddlers with moyamoya disease (MMD) using nomogram. Between January 2005 and December 2018, 74 toddlers with MMD underwent surgery in the Fifth Medical Centre, Chinese PLA General Hospital, 69 were < 4 years of age and included in the analysis. The modified Rankin scale (mRS) during follow-up evaluated clinical outcomes. To measure the effectiveness of EDAS, the annual risk of symptomatic infarction within the operated brain hemispheres was calculated. The event-free survival rate was determined using Kaplan-Meier curves. A nomogram generated using multivariate logistic regression analysis identified potential predictors associated with unfavorable outcomes. Additionally, discrimination, calibration, and clinical utility were assessed. A favorable clinical outcome was observed in 81.2% of the patients. The operated hemispheres showed an annual risk of 0.87% of symptomatic infarction and 0.23% of hemorrhage. Moreover, the 10-year event-free survival rates were 92.8% and 97.0% for symptomatic infarction and hemorrhage. Multivariate logistic analysis indicated that onset with infarction, initial mRS ≥ 3, and perioperative adverse events had significant and independent associations with unfavorable outcomes. However, an age at diagnosis of ≥ 2 years showed an association with favorable outcomes. Using these four factors, our model attained a concordance index of 0.912 (95% confidence interval, 0.842-0.982), well-fitted calibration curve, and cutoff value of 0.212 for predicting unfavorable outcomes. EDAS may prevent recurrent stroke and improve overall long-term clinical outcomes in toddlers with MMD. The developed nomogram accurately predicted unfavorable outcomes and assisted surgeons in patient evaluation.

Cerebral Vasculopathy in Children with Neurofibromatosis Type 1

Cerebrovascular abnormalities are a severe and often underrecognized complication of childhood neurofibromatosis type 1 (NF1). There are no prospective studies of cerebral vasculopathy in NF1; thus, the estimated frequency of vasculopathy varies between studies. The data is difficult to interpret due to the retrospective data collection and variability in whether imaging is done based on screening/surveillance or due to acute neurologic symptoms. The prevalent NF1-associated cerebral vasculopathy is moyamoya syndrome (MMS). Vascular changes can present without symptoms or with acute TIA or stroke-like symptoms or a range of progressive neurologic deficits. Advanced imaging may enhance sensitivity of neuroimaging in children. Medical and/or surgical interventions may prevent short- and long-term complications. Challenges for establishment of a screening protocol for cerebral vasculopathy in children with NF1 include the relatively large number of patients with NF1, the potential need for sedation to achieve quality imaging and the broad age range at time of detection for cerebral vascular changes. The goal of this review is to present the epidemiology, clinical presentation, imaging features and medical/surgical management of cerebral arteriopathies in children with NF1.

Adult Moyamoya Disease and Syndrome: Current Perspectives and Future Directions: A Scientific Statement From the American Heart Association/American Stroke Association

Adult moyamoya disease and syndrome are rare disorders with significant morbidity and mortality. A writing group of experts was selected to conduct a literature search, summarize the current knowledge on the topic, and provide a road map for future investigation. The document presents an update in the definitions of moyamoya disease and syndrome, modern methods for diagnosis, and updated information on pathophysiology, epidemiology, and both medical and surgical treatment. Despite recent advancements, there are still many unresolved questions about moyamoya disease and syndrome, including lack of unified diagnostic criteria, reliable biomarkers, better understanding of the underlying pathophysiology, and stronger evidence for treatment guidelines. To advance progress in this area, it is crucial to acknowledge the limitations and weaknesses of current studies and explore new approaches, which are outlined in this scientific statement for future research strategies.

Five-Year Stroke Risk and Its Predictors in Asymptomatic Moyamoya Disease: Asymptomatic Moyamoya Registry (AMORE)

BACKGROUND

Long-term outcomes are unknown in patients with asymptomatic moyamoya disease. In this report, we aimed to clarify their 5-year risk of stroke and its predictors.

METHODS

We are conducting a multicenter, prospective cohort study (Asymptomatic Moyamoya Registry) in Japan. Participants were eligible if they were 20 to 70 years, had bilateral or unilateral moyamoya disease, experienced no episodes suggestive of TIA and stroke; and were functionally independent (modified Rankin Scale score 0-1). Demographic and radiological information was collected at enrollment. In this study, they are still followed up for 10 years. In this interim analysis, we defined the primary end point as a stroke occurring during a 5-year follow-up period. Independent predictors for stroke were also determined, using a stratification analysis method.

RESULTS

Between 2012 and 2015, we enrolled 109 patients, of whom 103 patients with 182 involved hemispheres completed the 5-year follow-up. According to the findings on DSA and MRA, 143 hemispheres were judged as moyamoya disease and 39 hemispheres as questionable manifestations (isolated middle cerebral artery stenosis). The patients with questionable hemispheres were significantly older, more often male, and more frequently had hypertension than those with moyamoya hemisphere. Moyamoya hemispheres developed 7 strokes, including 6 hemorrhagic and 1 ischemic stroke, during the first 5 years. The annual risk of stroke was 1.4% per person, 0.8% per hemisphere, and 1.0% per moyamoya hemisphere. Independent predictor for stroke was Grade-2 choroidal anastomosis (hazard ratio, 5.05 [95% CI, 1.24-20.6]; P=0.023). Furthermore, microbleeds (hazard ratio, 4.89 [95% CI, 1.13-21.3]; P=0.0342) and Grade-2 choroidal anastomosis (hazard ratio, 7.05 [95% CI, 1.62-30.7]; P=0.0093) significantly predicted hemorrhagic stroke. No questionable hemispheres developed any stroke.

CONCLUSIONS

The hemispheres with asymptomatic moyamoya disease may carry a 1.0% annual risk of stroke during the first 5 years, the majority of which are hemorrhagic stroke. Grade-2 choroidal anastomosis may predict stroke, and the microbleeds and Grade-2 choroidal anastomosis may carry the risk for hemorrhagic stroke.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: UMIN000006640.

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.

Clinical and Genetic Characteristics of Patients with Moyamoya Disease who Experienced Both Ischemic and Hemorrhagic Events

OBJECTIVE

Cerebrovascular events in moyamoya disease are mainly classified into ischemic or hemorrhagic onset. It is rare for one patient to develop both ischemia and hemorrhage in moyamoya disease; detailed clinical course and genetic characteristics of such patients have not been elucidated. We aimed to clarify the clinical features of patients with both ischemic and hemorrhagic cerebrovascular events.

METHODS

We analyzed the background factors, radiological features, and genotype of ring finger protein 213 c.14429 G > A (p.Arg4810Lys) of patients with moyamoya disease who visited our hospital between 1996 and 2020, and experienced both ischemic and hemorrhagic cerebrovascular events. Additionally, we analyzed factors that caused subsequent hemorrhage in adult-onset ischemic moyamoya disease.

RESULTS

Of 262 patients, 12 presented with both ischemia and hemorrhage, of which, 4 exhibited pediatric onset and 8 had adult onset. In pediatric-onset subjects, ischemia was the initial event in all cases. Hemorrhagic events occurred at a median of 24.7 years postoperatively in patients who had undergone bypass surgery. In adult-onset subjects, ischemia preceded hemorrhage in 7 patients. In males, the interval to subsequent hemorrhage was significantly shorter for adult-onset ischemic moyamoya disease, and the hazard ratio for hemorrhagic events was 5.45. The ring finger protein 213 p.Arg4810Lys heterozygous variant was present in 9 patients.

CONCLUSIONS

A majority of patients with moyamoya disease with both ischemia and hemorrhage experience an ischemic event first. Patients who developed ischemia in childhood may develop subsequent hemorrhage in approximately 20-25 years after bypass surgery. Male sex is a risk factor for a subsequent hemorrhagic event in adult-onset ischemic moyamoya disease.

Angioarchitectural Factors Associated with Postoperative Cerebral Infarction in Ischemic Moyamoya Disease

Objective: To investigate the angioarchitectural factors associated with postoperative cerebral infarction in ischemic moyamoya disease. Methods: Data on patients who underwent surgery for ischemic MMD from 1 October 2015 to 31 October 2020, at Peking University International Hospital were collected and retrospectively analyzed. General conditions such as patient sex, age, site of surgery, preoperative manifestations such as TIA attack and old cerebral infarction, and seven angioarchitectural factors of the MMD based on DSA were selected and measured. Statistical analysis was performed by the Pearson chi-square statistic, analysis of variance (ANOVA), and multifactor logistic regression analysis. Results: Age (OR, 0.969; 95%CI, 0.939–1.000; p = 0.049), A1stenosis (OR, 5.843; 95%CI, 1.730–19.732; p = 0.004), M1stenosis (OR, 6.206; 95%CI, 2.079–18.526; p = 0.001), PCA anomalies (OR, 4.367; 95%CI, 1.452–13.129; p = 0.049), Unstable compensation (OR, 5.335; 95%CI, 1.427–19.948; p = 0.013), TIA (OR, 4.264; 95%CI, 1.844–9.863; p = 0.001), Old cerebral infarction (OR, 2.972; 95%CI, 1.194–7.397; p = 0.019). The above seven factors can be used in the regression equation to predict the probability of postoperative cerebral infarction. The prediction accuracy is 90.2%. Conclusions: Age, TIA attack, old cerebral infarction, and five angioarchitectural factors of MMD are strongly associated with postoperative cerebral infarction. Seven factors, including age, TIA attack, old infarction, and four angioarchitectural factors, can be taken to quantify the probability of surgical cerebral infarction in MMD.

Identification of moyamoya disease based on cerebral oxygen saturation signals using machine learning methods

Moyamoya is a cerebrovascular disease with a high mortality rate. Early detection and mechanistic studies are necessary. Near-infrared spectroscopy (NIRS) was used to study the signals of the cerebral tissue oxygen saturation index (TOI) and the changes in oxygenated and deoxygenated hemoglobin concentrations (HbO and Hb) in 64 patients with moyamoya disease and 64 healthy volunteers. The wavelet transforms (WT) of TOI, HbO and Hb signals, as well as the wavelet phase coherence (WPCO) of these signals from the left and right frontal lobes of the same subject, were calculated. Features were extracted from the spontaneous oscillations of TOI, HbO and Hb in five physiological activity-related frequency segments. Machine learning models based on support vector machine (SVM), random forest (RF) and extreme gradient boosting (XGBoost) have been built to classify the two groups. For 20-min signals, the 10-fold cross-validation accuracies of SVM, RF and XGBoost were 87%, 85% and 85%, respectively. For 5-min signals, the accuracies of the three methods were 88%, 88% and 84%, respectively. The method proposed in this article has potential for detecting and screening moyamoya with high proficiency. Evaluating the cerebral oxygenation with NIRS shows great potential in screening moyamoya diseases.

Characterizing the neurocognitive profiles of children with moyamoya disease using the Das Naglieri cognitive assessment system

Although cognitive impairment is well-documented in children with moyamoya disease (MMD), selective decline in specific neurocognitive domains remains controversial. The purpose of this study was to characterize the neurocognitive profile of children with MMD using the Das Naglieri Cognitive Assessment System (CAS) and the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV). We analyzed the neurocognitive data of 30 children (median age, 7 years) with MMD who were assessed with the CAS and the WISC-IV before surgery. We focused on the comparison of standard scores and intraindividual differences across domains. The CAS scores significantly varied across four measures (standard scores, p < 0.001; intraindividual differences, p < 0.001). Post-hoc analyses revealed that the standard scores and intraindividual differences for successive processing were significantly lower than those for planning and attention. The WISC-IV scores did not significantly vary among the four measures, although the working memory index was the lowest among the four measures. The within-individual weakness in successive processing, a form of working memory function, may be a distinct characteristic of children with MMD. The CAS may be more sensitive than the WISC-IV for detecting this selective neurocognitive weakness in children with MMD.

Clinical Management of Moyamoya Patients

Moyamoya angiopathy (MMA) is a peculiar cerebrovascular condition characterized by progressive steno-occlusion of the terminal part of the internal carotid arteries (ICAs) and their proximal branches, associated with the development of a network of fragile collateral vessels at the base of the brain. The diagnosis is essentially made by radiological angiographic techniques. MMA is often idiopathic (moyamoya disease-MMD); conversely, it can be associated with acquired or hereditary conditions (moyamoya Syndrome-MMS); however, the pathophysiology underlying either MMD or MMS has not been fully elucidated to date, and this poor knowledge reflects uncertainties and heterogeneity in patient management. MMD and MMS also have similar clinical expressions, including, above all, ischemic and hemorrhagic strokes, then headaches, seizures, cognitive impairment, and movement disorders. The available treatment strategies are currently shared between idiopathic MMD and MMS, including pharmacological and surgical stroke prevention treatments and symptomatic drugs. No pharmacological treatment able to reverse the progressive disappearance of the ICAs has been found to date in both idiopathic and syndromic cases. Antithrombotic agents are usually prescribed in ischemic MMA, although the coexisting hemorrhagic risk should be considered. Surgical revascularization techniques, which are currently the best available treatment in symptomatic MMA, are associated with good long-term outcomes and reduced ischemic and hemorrhagic risks. Given the lack of dedicated randomized clinical trials, current treatment is mainly based on observational studies and physicians’ and surgeons’ expertise.

Quiet Diffusion-weighted MR Imaging of the Brain for Pediatric Patients with Moyamoya Disease

PURPOSE

Diffusion-weighted MRI (DWI) is an essential sequence for evaluating pediatric patients with moyamoya disease (MMD); however, acoustic noise associated with DWI may lead to motion artifact. Compared with conventional DWI (cDWI), quiet DWI (qDWI) is considered less noisy and able to keep children more relaxed and stable. This study aimed to evaluate the suitability of qDWI compared with cDWI for pediatric patients with MMD.

METHODS

In this observational study, MR examinations of the brain were performed either with or without sedation in pediatric patients with MMD between September 2017 and August 2018. Three neuroradiologists independently evaluated the images for artifacts and restricted diffusion in the brain. The differences between qDWI and cDWI were compared statistically using a chi-square test.

RESULTS

One-hundred and six MR scans of 56 patients with MMD (38 scans of 15 sedated patients: 6 boys and 9 girls; mean age, 5.2 years; range, 1-9 years; and 68 scans of 42 unsedated patients: 19 boys and 23 girls; mean age, 10.7 years; range, 7-16 years) were evaluated. MR examinations were performed either with or without sedation (except in one patient). In sedated patients, no artifact other than susceptibility was observed on qDWI, whereas four artifacts were observed on cDWI (P = .04). One patient awoke from sedation during cDWI scanning, while no patient awoke from sedation during qDWI acquisition. For unsedated patients, three scans showed artifacts on qDWI, whereas two scans showed artifacts on cDWI (P = .65). Regarding restricted diffusion, qDWI revealed three cases, while two cases were found on cDWI (P = .66).

CONCLUSION

qDWI induced fewer artifacts compared with cDWI in sedated patients, and similar frequencies of artifacts were induced by qDWI and by cDWI in unsedated patients. qDWI showed restricted diffusion comparable to cDWI.

Differences in Clinical Features among Different Onset Patterns in Moyamoya Disease

Moyamoya disease is characterized by severe stenosis at the ends of the bilateral internal carotid arteries and the development of collateral circulation. The disease is very diverse in terms of age at onset, onset patterns, radiological findings, and genetic phenotypes. The pattern of onset is mainly divided into ischemic and hemorrhagic onsets. Recently, the opportunity to identify asymptomatic moyamoya disease, which sometimes manifests as nonspecific symptoms such as headache and dizziness, through screening with magnetic resonance imaging has been increasing. Various recent reports have investigated the associations between the clinical features of different onset patterns of moyamoya disease and the corresponding imaging characteristics. In this article, we have reviewed the natural history, clinical features, and imaging features of each onset pattern of moyamoya disease.

Late morbidity and mortality following revascularization surgery for moyamoya disease in the pediatric population

OBJECTIVE

There are limited reports on long-term morbidity in pediatric patients who have undergone surgical revascularization for moyamoya disease (MMD). Here, the authors report long-term morbidity and mortality in a population of pediatric patients who underwent pial synangiosis for MMD from 1988 through 2016.

METHODS

A single-center retrospective review of the hospital and personal operative databases of the senior authors was carried out to identify all patients who were treated for MMD at Boston Children's Hospital between 1988 and 2016, and who experienced any episode of late morbidity or mortality, which the authors defined as an event resulting in significant neurological deficit or death occurring more than 1 year after revascularization surgery. Hospital records were reviewed to determine pertinent demographic data, the initial mode of patient presentation, and associated comorbidities. Radiographic studies, when available, were reviewed for documentation of the diagnosis and for confirmation of the late complication, and the literature on this topic was reviewed.

RESULTS

In total, 460 patients with MMD underwent surgery between 1988 and 2016 using the pial synangiosis surgical technique; 15 (3.3%) of these patients (9 females and 6 males) experienced documented late death (n = 14) or severe morbidity (n = 1). The median age at revascularization surgery was 8.0 years (range 1-21 years). The causes of these late complications were grouped into three etiologies: intraventricular or intracerebral hemorrhage (n = 8), systemic complications related to associated comorbidities or preoperative disabilities (n = 5), and the development of malignant brain tumors (n = 2). Four patients whose MMD was associated with a history of cranial radiation therapy died. These events occurred from as early as 2 years to as late as 27 years postoperatively.

CONCLUSIONS

The risk of late morbidities and mortality following pial synangiosis for MMD in the pediatric patient appeared to be low. Nevertheless, the occurrence of catastrophic cerebrovascular events, particularly intracerebral and intraventricular hemorrhage in the otherwise neurologically stable revascularized patient, was concerning. Although there is value in long-term surveillance of patients who have undergone surgery for MMD, from both a neurological and a general medical standpoint, particularly in patients with the risk factor of prior cranial radiation therapy, it is not clear from the data how the late deaths in this population could have been prevented.

Preoperative Risks of Cerebral Infarction in Pediatric Moyamoya Disease

[Figure: see text].

Recurrent hemorrhage risk associated with medial target medullary artery anastomosis from the periventricular collateral vessel in adult patients with moyamoya disease

BACKGROUND

Although the association between periventricular target collateral anastomosis and recurrent ipsilateral hemorrhage has been evaluated in adult patients with moyamoya disease (MMD), no studies have investigated the relationship between target anastomotic territory and recurrent ipsilateral hemorrhage. The goal of this study was to assess this association.

METHODS

Consecutive adult MMD patients who had experienced initial intracranial hemorrhage and undergone conservative treatment were included. Two readers assessed angiographic results to identify the target anastomotic territory (medial medullary artery, lateral medullary artery, multiple medullary arteries, or nonmedullary artery) responsible for the hemorrhage. Cox proportional hazard regression models were used to estimate the risk of recurrent hemorrhage.

RESULTS

In the 36 hemispheres with initial hemorrhage, the target anastomotic territory was in the anastomotic territory of the medial medullary artery in 10 (27.8%), lateral medullary artery in 15 (41.7%), multiple medullary arteries in 2 (5.6%), and a nonmedullary artery in 9 (25.0%) hemispheres. During 45.1 ± 40.0 months of follow-up, recurrent ipsilateral hemorrhage occurred in 44.4% (16/36) of hemispheres. The target anastomotic territories responsible for the recurrent event were in the anastomotic territory of the medial medullary artery in 9 (56.3%) hemispheres, lateral medullary artery in 6 (37.5%) hemispheres, and multiple medullary arteries in 1 (6.3%) hemisphere. The anastomotic territory of the medial medullary artery was associated with recurrent hemorrhage before (HR = 2.94; 95% CI, 1.07-8.08; p = 0.037) and after (HR = 6.65; 95% CI, 1.32-33.60; p = 0.022) adjustments were made for confounding factors.

CONCLUSIONS

The incidence of recurrent ipsilateral hemorrhage varies with the target anastomotic territory in adult patients with MMD. Medial target medullary artery anastomosis is a significant risk factor for recurrent ipsilateral hemorrhage.

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.

De Novo Renal Artery Stenosis Developed in Initially Normal Renal Arteries during the Long-Term Follow-Up of Patients with Moyamoya Disease

BACKGROUND

The de novo occurrence of renal artery stenosis in renal arteries that were angiographically confirmed to be normal in the past has never been reported before in patients with moyamoya disease.

CASE DESCRIPTION

During the long-term follow-up of pediatric patients with moyamoya disease, we observed 3 patients who developed de novo renal artery stenosis in arteries that had been angiographically confirmed to be normal 1 year after the surgery (7 years on average, ranging from 4 to 11 years). All of these patients were neurologically stable after successful indirect bypass surgery during childhood. However, more than 10 years after the surgery (15 years on average, ranging from 14 to 23 years), they developed hypertension and were found to have de novo renal artery stenosis, which was ameliorated by endovascular angioplasty. During the follow-up after angioplasty, 1 patient experienced a recurrence of hypertension and required a second and third angioplasty for restenosis. Another patient died of intracranial hemorrhage 2 years after angioplasty. In the 2 surviving patients, gene analysis of the ring finger protein 213 (RNF213; p.R4810K) point mutation, the susceptibility gene for moyamoya disease in the Asian population, was positive for the heterozygous variant.

CONCLUSIONS

De novo renal artery stenosis might develop in initially normal arteries during long-term follow-up, particularly among pediatric patients with moyamoya disease. Considering the extracranial manifestations of moyamoya disease, clinicians should keep in mind that de novo renal artery stenosis could emerge later in their life. Thus, it is crucial to continue to follow these patients for decades, even if the patients are neurologically stable after bypass surgery. Monitoring for blood pressure and the de novo occurrence of renal artery stenosis is important to prevent hypertension-related morbidity and mortality, such as intracranial hemorrhage, in this disease population.

Ischemic sequelae and other vascular diseases

Although pediatric stroke is associated with higher survival rates compared with adult stroke, a substantial body of evidence indicates significant neuropsychologic morbidity in pediatric stroke survivors. Neuroplasticity does not guarantee good outcome in children. The general trends observed in the literature are reviewed as is the profile observed in common causes of pediatric stroke: congenital heart disease, moyamoya disease, and sickle cell disease. The neuropsychologic profile of pediatric stroke patients is heterogeneous due to the multiplicity of associated causes. Stroke in early infancy and large strokes are associated with cognitive impairment while more limited disorders, such as phasic deficit, are observed in childhood stroke. Executive dysfunction is common in pediatric stroke, but social interaction skills are usually preserved. Congenital heart disease and sickle cell disease are associated with global neuropsychologic dysfunction while cognition is usually preserved in moyamoya. Executive dysregulation is instead more frequently reported in this population. Further study of maladaptive processes after pediatric stroke will allow identification of predictors of functional and neuropsychologic outcomes and permit personalization of care.

Cognitive Performance Profile in Pediatric Moyamoya Disease Patients and Its Relationship With Regional Cerebral Blood Perfusion

Object: Moyamoya disease affects the cognitive function of pediatric patients, and compromised cerebral blood flow might be the potential cause. We aimed to explore the specific correlation between cognitive impairment and regional perfusion status in pediatric moyamoya disease patients.

Methods: We prospectively enrolled consecutive pediatric moyamoya disease patients admitted to Beijing Tiantan Hospital from July 2017 to March 2019. Arterial spin-labeling magnetic resonance and the Wechsler Intelligence Scale for Children (the 4th edition) were performed on all participants. The cognitive performance of patients was analyzed, and its correlation to cerebral perfusion status was also investigated in the region of interest-based analysis.

Results: A total of 21 patients met the inclusion criteria (mean aged 11.14 ± 2.82, male: female = 11:10). Six patients (28.6%) showed no cognitive deficits in any index score, while 15 (71.4%) showed cognitive deficits with differing severity. Nine (42.9%) patients showed overall cognitive impairment, and all cognitive index scores except for Verbal Comprehension Index were significantly lower than the mean scores of normative data with corresponding age. Perceptual Reasoning Index (p = 0.019) were statistically lower in patients with radiologically confirmed cerebral infarction. Suzuki stage of the left hemisphere negatively correlated to Full-scale Intelligence Quotient (r = −0.452, p = 0.039). Region of Interest analysis showed that cerebral blood flow of the left temporal lobe independently associated with the Processing Speed Index (β = 0.535, p = 0.041).

Conclusion: Pediatric moyamoya disease patients exhibited different levels of cognitive impairment. Cerebral infarction is related to poorer perceptual reasoning ability. Cerebral blood flow in the left temporal lobe positively correlates with processing speed.

The Targeted Bypass Strategy for Preventing Hemorrhage in Moyamoya Disease: Technical Note

Although direct bypass is effective at preventing intracranial hemorrhage in moyamoya disease, the optimal strategy for achieving this purpose has rarely been addressed. The tailored targeting bypass strategy is a novel technical modification of direct bypass focused on hemorrhage prevention. The strategy is based on the promising theory of periventricular anastomosis, which explains the mechanism of hemorrhage in moyamoya disease. The strategy is defined as the use of multi-imaging modalities to predetermine in a tailored manner a target vessel at the point at which the medullary artery directly extends from the periventricular anastomosis of interest. Direct bypass with a wide craniotomy was performed on 13 hemispheres in eight patients according to this strategy. Marked shrinkage of the periventricular anastomosis of interest was observed in all but one hemisphere after surgery, and no new hemorrhages have occurred as of this writing. The present case series illustrates the technical aspects and preliminary results of the tailored targeting bypass strategy, an approach that might expand the potential of direct bypass in preventing hemorrhage.

Revascularization Surgery in Childhood Associated with a Low Incidence of Microbleeds in Adult Patients with Moyamoya

BACKGROUND

The clinical significance of asymptomatic microbleeds in moyamoya disease remains unclear. The purpose of this study was to clarify the relationship between bypass surgery and the incidence of asymptomatic microbleeds.

METHODS

This retrospective study included 142 adult patients (mean age, 37.7 ± 13.5 years) with moyamoya disease, 36 of whom (25.3%) underwent bypass surgery in childhood. Hemorrhagic onset was diagnosed in 31 patients (21.8%). The incidence of microbleeds was evaluated on T2*-weighted or susceptibility-weighted imaging from 3-T magnetic resonance imaging. The patients were subsequently categorized into MBs (microbleeds) or non-MBs groups. Because previous microbleeds potentially lead to hemorrhage, the MBs group was defined as patients with radiographic evidence of bleeding, including asymptomatic microbleeds and/or hemorrhagic onset. The association of baseline characteristics was evaluated.

RESULTS

Asymptomatic microbleeds were detected in 38 patients (26.8%). Of 31 patients with hemorrhagic onset, 18 had microbleeds, whereas 13 had no microbleeds. Therefore, 51 patients (35.9%) were classified into the MBs group. Bypass surgery in childhood (MBs, 7.8% vs. non-MBs, 35.2%; P < 0.01) and age (MBs, 42.9 ± 1.8 years vs. non-MBs, 34.7 ± 1.4 years; P < 0.01) were statistically significant factors associated with microbleeds, but only bypass surgery in childhood remained statistically significant after multivariable adjustment (odds ratio, 0.25; 95% confidence interval, 0.07-0.87; P = 0.03).

CONCLUSIONS

This study shows the clinical significance of revascularization surgery in childhood associated with a low incidence of asymptomatic microbleeds in adult patients with moyamoya disease. This finding indicates that a newly established bypass can reduce hemodynamic overstress.

Long-Term Outcomes of Indirect Bypass for 629 Children With Moyamoya Disease: Longitudinal and Cross-Sectional Analysis

Background and Purpose- In pediatric moyamoya disease, there are few reports on the efficacy of surgical intervention for stroke prevention. We evaluated the long-term outcomes of indirect bypass surgery on a relatively large number of children with moyamoya disease in a single center. Methods- From August 1988 to December 2012, 772 children underwent indirect bypass surgery. This study included 629 patients who were followed up for >5 years, excluding patients with moyamoya syndrome. The mean clinical follow-up duration was 12 years (range, 5-29 years). Cross-sectional analysis was performed based on either Karnofsky Performance Scale or Lansky Play Performance Scale to evaluate overall clinical outcomes and factors associated with unfavorable outcomes. To analyze the longitudinal effect of surgery, the annual risk of symptomatic infarction or hemorrhage on the operated hemisphere after indirect bypass surgery was calculated with a person-year method, and the event-free survival rate was evaluated using the Kaplan-Meier method. Results- The overall clinical outcome was favorable in 95% of the patients. The annual risks of symptomatic infarction and hemorrhage on the operated hemispheres were 0.08% and 0.04%, respectively. Furthermore, the 10-year event-free survival rates for symptomatic infarction and hemorrhage were 99.2% and 99.8%. Conclusions- Indirect bypass surgery could provide satisfactory long-term improvement in overall clinical outcome and prevention of recurrent stroke in children with moyamoya disease.

Modified encephalo-duro-periosteal-synangiosis (EDPS) for the revascularization of anterior cerebral artery territory in moyamoya disease: A single-center experience

OBJECTIVES

Anterior cerebral artery (ACA) territory, a crucial area of intellectual development in children, is frequently involved in the progress of moyamoya disease (MMD). However, revascularization surgeries for this area are not as established as surgeries for middle cerebral artery (MCA) territory. This study aimed to describe our experience and study the effect of revascularizing ACA territory with periocranium and dural leaflets, which is referred to as 'encephalo-duro-periosteal-synangiosis (EDPS)'.

PATIENTS AND METHOD

Fourteen hemispheres of 9 MMD patients who had undergone EDPS from November 2015 till July 2017 in our hospital were retrospectively included. Clinical characteristics and procedure-related information were recorded. Cerebral perfusion was evaluated by computed tomography perfusion (CTP). Absolute and relative (r) CTP parameters of ROIs in ACA territory at the level of centrum semiovale and middle basal ganglia were calculated. Preoperative and postoperative parameters were compared.

RESULTS

All EDPS procedures were technically successful with no postoperative complications. The mean operating time was 75.00 ± 22.53 min per hemisphere. Postoperative absolute cerebral blood flow (CBF), rCBF were significantly increased and absolute time to peak (TTP), rTTP, absolute mean transit time (MTT) were significantly reduced in ACA territory at centrum semiovale level (P = 0.002, 0.045, 0.007, 0.005 and 0.039 respectively). Improved outcomes were achieved in five patients, stabilization in three and one patient had deterioration out of intracerebral hemorrhage during follow-up.

CONCLUSION

EDPS is a simple but effective technique to revascularize ACA territory for MMD. EDPS significantly improved cerebral blood perfusion of frontal lobe in the majority of patients without increasing procedure-related risks.