I saw the 'puff of smoke' sign before it vanished into thin air

Moyamoya is characterized as a non-atherosclerotic and non-inflammatory vasculopathy that leads to progressive stenosis of the intracranial internal carotid arteries as well as the Circle of Willis. While it can be idiopathic (Moyamoya disease) or associated with another condition (Moyamoya syndrome), there is a characteristic 'puff of smoke' sign that can be appreciated on cerebral angiography.

Rare combo: moyamoya and lupus in men

Moyamoya syndrome (MMS) is a rare, chronic, progressive cerebrovascular disorder characterized by stenosis at the apices of the intracranial internal carotid arteries, including the proximal anterior cerebral arteries and middle cerebral arteries. Cerebral angiography images are used for detection through measurement. Systemic lupus erythematosus (SLE) is an autoimmune disease that can cause multisystemic involvement. The coexistence of SLE and MMS has been rarely reported in the literature. A 46-year-old male patient with malar rash, Raynaud phenomenon presented to the hospital with a complaint of weakness in the left lower extremity, which began 3 days before the date of the visit. In the diffusion magnetic resonance imaging, multiple diffusion restrictions were observed in the right frontal region. The patient underwent MR angiography, revealing stenosis in the terminal and supraclinoid segments of the right internal carotid artery, which made us consider moyamoya disease. This patient, with a malar rash and Raynaud's, a positive antibody profile, was diagnosed as a male with SLE accompanied by MMS.

Comparison between moyamoya disease and moyamoya syndrome in Israel

BACKGROUND AND AIMS

Moyamoya is a chronic brain vasculopathy involving the distal intracranial internal carotid artery (ICA) or proximal middle cerebral artery (MCA). Moyamoya patients can be divided into those with primary moyamoya disease (MMD) and those with moyamoya secondary to other known causes such as intracranial atherosclerosis (moymoya syndrome [MMS]). Our aim was to compare the characteristics of MMD patients to those of MMS patients in a sample of Israeli patients seen over the course of 20 years at a tertiary referral center.

METHODS

Included patients were diagnosed with either MMD or MMS based on typical imaging findings and the presence or absence of known concomitant vascular risk factors or associated disorders and vascular disease. Patients with MMS were compared to those with MMD. Demographics, symptoms, signs, and radiological data were compared between the groups. Treatment options and long-term rates of recurrent stroke and functional outcome were also studied.

RESULTS

Overall, 64 patients were included (25 MMD, 39 MMS). Patients with MMD were significantly younger (median IQR 20 (7-32) vs. 40 (19-52); p=0.035). Patients with MMS more often had vascular risk factors but there were no significant differences in clinical presentations or long-term disability rates between the groups and a similar proportion of patients underwent surgical interventions to restore hemispheric perfusion in both groups (48% vs. 44% MMS vs. MMD; p=0.7). Almost one in four patient had a recurrent stroke after the initial diagnosis in both groups. Most recurrences occurred in the pre-surgery period in the MMS group and in the post-surgery period in the MMD group.

CONCLUSIONS

There were no statistically significant differences in clinical or radiological presentations between the MMS and MMD patients. The course is not benign with recurrent stroke occurring in as many as 25%. More data is needed in order to identify those at high risk for stroke occurrence and recurrence.

Effect of revascularization surgery on cerebral hemodynamics in adult moyamoya disease

OBJECTIVE

Few studies have reported local hemodynamic changes after revascularization surgery. This study aimed to identify regional hemodynamic changes after combined revascularization surgery for moyamoya disease using single-photon emission computed tomography with N-isopropyl-p-123I-iodoamphetamine.

METHODS

A total of 46 adults with moyamoya disease who underwent combined revascularization surgery from August 2009 to July 2021 at our facility were enrolled. The combined bypass procedure comprised a single direct bypass to the motor area and encephalo-duro-arterio-myo-synangiosis. The preoperative and postoperative cerebral blood flow (CBF) and cerebral vascular reserve (CVR) in the genu; precentral, central, parietal, angular, temporal, and posterior regions; splenium; hippocampus; and cerebellum were measured. To modify the examination variability, the cerebral-to-cerebellar activity ratio (CCR) was calculated by dividing the counts in the region by those in the cerebellum (CBF-CCR and CVR-CCR).

RESULTS

Postoperatively, asymptomatic cerebral infarction occurred in three (6.5%) patients. The CBF-CCR and CVR-CCR improved in the precentral, parietal, and temporal regions and in the overall middle cerebral artery (MCA) territory. Sub-analysis of anterior cerebral artery (ACA) and posterior cerebral artery (PCA) territory hemodynamics revealed that patients with normal preoperative hemodynamics showed no changes in the CBF-CCR and CVR-CCR postoperatively, whereas patients with preoperative perfusion impairment exhibited improved CVR-CCR in the ACA territory (0.13-0.3, p=0.019) and CBF-CCR in the PCA territory (0.93-0.96, p=0.0039).

CONCLUSION

Combined revascularization surgery with single bypass to the motor area improved hemodynamics in the primary targeted MCA territory and in the ACA and PCA territories among patients with preoperative hemodynamic impairment.

Cranioplasty with Direct Revascularization in Hemorrhagic Moyamoya Disease: 2-Dimensional Operative Video

Moyamoya disease is a progressive nonatherosclerotic stenosis of the terminal segments of the arteries of the Circle of Willis. Hemorrhagic presentation is a life-threatening condition, associated with an increased risk of rebleeding and ischemic events.1-7 We present the case of a 65-year-old woman with a right intracerebral hemorrhage who underwent emergency hematoma evacuation without bone flap replacement (Video 1). The investigation confirmed the diagnosis of Moyamoya disease and demonstrated hypoperfusion of the right cerebral hemisphere. Late angiography depicted no transdural collaterals through the bone defect and demonstrated preservation of the superficial temporal artery (STA). Next, it was chosen to perform 1-stage cranioplasty with direct revascularization. We detached the temporal fascia from the muscle and created a window through the fascia to give STA passage in a corridor through the temporal muscle until the brain's surface. Vascular anastomosis was performed with an interrupted suture line employing a 10-0 nylon thread. Flow within the right middle cerebral artery was retrograde, coming from branches of the posterior cerebral artery, and the end-to-side anastomosis was placed to orientate the STA flow in the same direction as in the middle cerebral artery. We used a custom-made titanium plate for the cranioplasty and gave enough room inferiorly for the course of STA. In the end, we sutured the temporal fascia to the titanium plate for a better cosmetic result. To avoid additional unnecessary procedures, the performance of direct revascularization during the cranioplasty is feasible and deserves additional investigation as a tool to prevent new hemorrhagic or ischemic events. Informed consent was obtained from the patient for the procedure and publication of this operative video.

Systematic review and illustrative case report

The coexistence of Moyamoya Syndrome with Arteriovenous Malformation is exceedingly rare. Here, we present the case of a 37-year-old female patient diagnosed with AVM in the right parietal lobe, accompanied by severe stenosis of the right middle cerebral artery and right anterior cerebral artery, along with moyamoya collateral induction. Our objective was to investigate the frequency and mutual influence of these conditions, and to determine a preferable treatment strategy by conducting a comprehensive review of previous case reports. We conducted a thorough search of PubMed, Scopus, and Web of Science databases, adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our review encompassed 36 publications, reporting a total of 64 cases of AVM coexisting with Moyamoya Syndrome. Notably, bilateral stenosis was observed in half of the cases. Among patients with unilateral stenosis, AVM was localized in the opposite hemisphere only in 2 cases. Treatment approaches varied, with 18 cases undergoing active treatment for both stenosis and AVM, 11 cases treating stenosis prior to AVM, 5 cases addressing AVM first, and 3 cases treating both AVM and stenosis simultaneously. Embolization, either standalone or supplemented by stereotactic radiosurgery, was employed in six cases. Stereotactic radiosurgery alone was utilized in 12 cases, while 15 patients underwent surgical removal of the AVM. Our findings provide valuable insights for neurosurgeons managing patients with concurrent AVM and Moyamoya Syndrome. The variety of treatment approaches observed in the literature underscores the complexity of these cases, emphasizing the need for individualized strategies. This information may guide future systematic reviews and meta-analyses, contributing to a better understanding of the optimal management of these rare coexisting vascular pathologies.

Transcranial Doppler in Childhood Moyamoya: An Underutilized Tool?

BACKGROUND

Children with moyamoya are at high risk for incident and recurrent stroke. Transcranial Doppler (TCD) ultrasound is an attractive option to screen high-risk populations for moyamoya and to provide stroke risk stratification information due to its safety and cost-effectiveness. We used TCD to evaluate cerebral blood flow velocities in children with presurgical moyamoya and to determine if velocities differ between children with stable and unstable disease.

METHODS

Fourteen participants aged ≤21 years with a radiographic diagnosis of moyamoya or moyamoya-like arteriopathy underwent a research TCD at a median age of 7.2 years. TCDs were performed outside of the setting of acute stroke and before surgical revascularization. Arteriopathy was classified as unstable if the participant had a stroke or transient ischemic attack within three months preceding the TCD.

RESULTS

Middle cerebral artery and internal carotid artery (ICA) blood flow velocities were elevated. The median M1 velocity was 138 cm/s (interquartile range [IQR] 106 to 168). Individual M1 flow velocities were a median of 5.0 S.D.s above age-based normative values. The median distal ICA velocity was 146 cm/s (IQR 124 to 163). Individual ICA flow velocities were a median of 5.9 S.D.s above normative values. Participants with unstable arteriopathy had higher M1 velocities compared with those with stable arteriopathy (170 vs 119 cm/s, P = 0.0003). We did not identify velocity differences based on comorbid conditions or age.

CONCLUSIONS

These preliminary data suggest that TCD is a promising tool for screening for cerebral arteriopathies in high-risk pediatric populations and assessment for unstable disease.

Extracranial-Intracranial Bypass for Moyamoya Disease: The Influence of Racial and Socioeconomic Disparities on Outcomes - A National Inpatient Sample Analysis

BACKGROUND

Extracranial-intracranial (EC-IC) bypass is an established therapeutic option for Moyamoya disease (MMD). However, little is known about the effects of racial and ethnic disparities on outcomes. This study assessed trends in EC-IC bypass outcomes among MMD patients stratified by race and ethnicity.

METHODS

Utilizing the US National Inpatient Sample, we identified MMD patients undergoing EC-IC bypass between 2002 and 2020. Demographic and hospital-level data were collected. Multivariable analysis was conducted to identify independent factors associated with outcomes. Trend analysis was performed using piecewise joinpoint regression.

RESULTS

Out of 14,062 patients with MMD, 1771 underwent EC-IC bypass. Of these, 60.59% were White, 17.56% were Black, 12.36% were Asians, 8.47% were Hispanic, and 1.02% were Native Americans. Nonhome discharge was noted in 21.7% of cases, with a 6.7% death and 3.8% postoperative neurologic complications rates. EC-IC bypass was more commonly performed in Native Americans (23.38%) and Asians (17.76%). Hispanics had the longest mean length of stay (8.4 days) and lower odds of nonhome discharge compared to Whites (odds ratio: 0.64; 95% confidence interval: 0.40-1.03; P = 0.04). Patients with Medicaid, private insurance, self-payers, and insurance paid by other governments had lower odds of nonhome discharge than those with Medicare.

CONCLUSION

This study highlights racial and socioeconomic disparities in EC-IC bypass for patients with MMD. Despite these disparities, we did not find any significant difference in the quality of care. Addressing these disparities is essential for optimizing MMD outcomes.

Analysis of macula structural changes in Moyamoya disease using AI-assisted OCT

OBJECTIVE

To investigate macula structure thickness and volume changes in patients with moyamoya disease (MMD).

METHOD

In this cross-sectional study, we used artificial intelligence (AI) -assisted optical coherence tomography (OCT) to analyze the thickness and volume of macula in Moyamoya patients. ETDRS zoning divides the macula into nine different regions. In 15 patients with radial scanning OCT, the average thickness and volume of retina, RNFL, GCL, and choroid in these regions were measured. In 30 patients with radial or horizontal scanning OCT, based on the anatomical structure, the macula is divided into seven segments. Mean Sattler layer-choriocapillaris complex thickness (SLCCT), Haller layer thickness, and total choroidal thickness were measured for each segment using AI-assisted OCT.

RESULTS

We recruited 30 patients (59 eyes) with MMD. In the 15 patients (29 eyes) who underwent radial scanning OCT, no significant change in retina, RNFL, GCL, and choroidal thickness was identified between the two groups (p > 0.05). There was no significant change in retina, RNFL, or choroidal volume between the two groups in different ETDRS macula regions (p > 0.05). The GCL volume in the macula's inner ring nasal portion (IN) was significantly lower. SLCCTs were considerably reduced in six macula regions in moyamoya groups (p < 0.05). There was no statistically significant change in Haller layer thickness. Only the nasal perifovea (PE_N) exhibited a significant variation in choroidal thickness. The Moyamoya group showed reduced choroidal thickness in PE_N segment.

CONCLUSION

In patients with MMD, there is thinning of the Sattler layer-choriocapillaris complex in the choroid.

Posterior cerebral artery involvement in unilateral moyamoya disease is exclusively ipsilateral and influenced by RNF213 mutation gene dose: The SUPRA Japan study: PCA involvement in unilateral moyamoya

OBJECTIVES

The characteristics and clinical implications of posterior cerebral artery (PCA) involvement in unilateral moyamoya disease (U-MMD), such as laterality, frequency of the RNF213 p.R4810K mutation, and clinical outcomes, have not been well studied.

POPULATION AND METHODS

We analyzed a cohort of 93 patients with U-MMD who participated in the SUPRA Japan study. Clinical characteristics and radiological examinations were collected from medical records. The presence of the p.R4810K mutation was determined using a TaqMan assay. The clinical outcome was assessed using the modified Rankin Scale (mRS). Univariate and multivariate logistic regression analyses were performed to assess the associations.

RESULTS

Among the patients with U-MMD, PCA involvement was observed in 60.0 % (3/5) of patients with homozygous mutation, 11.3 % (7/62) of those with heterozygous mutation, and 3.8 % (1/26) of those with wild type, showing a significant linear trend (p < 0.001 for trend). PCA involvement was observed exclusively on the same side as the affected anterior circulation. Dyslipidemia and cerebral infarction at initial onset were independently associated with mRS ≥1. Hypertension was associated with mRS ≥1 and it was also linked to infarction at initial onset, suggesting a potential confounding effect. Although PCA involvement showed a trend for higher mRS, it was not statistically significant.

CONCLUSIONS

Our findings indicate a gene dose effect of the p.R4810K mutation on PCA involvement, with the homozygous state showing the most significant effect. Both genetic and modifiable factors such as dyslipidemia may influence the progression of U-MMD.

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.

Outcomes after surgical revascularization for adult Moyamoya disease: A Southeast Asian tertiary centre experience

There are numerous studies on the natural history and outcomes of adult Moyamoya disease (MMD) in the literature, but limited data from Southeast Asian cohorts. Hence, we aimed to retrospectively review the clinical characteristics and outcomes after surgical revascularization for adult MMD in our Southeast Asian cohort. Patients were included if they were above 18 years old at the first surgical revascularization for MMD, and underwent surgery between 2012 and 2022 at the National University Hospital, Singapore. The outcomes were transient ischemic attack (TIA), ischemic stroke, intracerebral hemorrhage, and all-cause mortality during the postoperative follow-up period. In total, 26 patients who underwent 27 revascularization procedures were included. Most patients were of Chinese ethnicity, and the mean (SD) age at the time of surgery was 47.7 (12.6) years. The commonest clinical presentation was intracerebral hemorrhage, followed by TIA and ischemic stroke. Direct revascularization with superficial temporal artery-middle cerebral artery (STA-MCA) bypass was the most common procedure (24/27 surgeries, 88.9 %). The mean (SD) follow-up duration was 4.2 (2.5) years, during which the overall incidence of postoperative TIA/stroke was 25.9 % (7/27 surgeries), with most cases occurring within 7 days postoperatively. There were no mortalities during the postoperative follow-up period. Risk factors for 30-day postoperative TIA/stroke included a higher number of TIAs/strokes preoperatively (p = 0.044) and indirect revascularization (p = 0.028). Diabetes mellitus demonstrated a trend towards an increased risk of 30-day postoperative TIA/stroke, but this was not statistically significant (p = 0.056). These high-risk patients may benefit from more aggressive perioperative antithrombotic and hydration regimens.

Relative anemia and perioperative stroke in children with moyamoya

OBJECTIVES

Surgical revascularization for moyamoya arteriopathy decreases long-term stroke risk but carries a risk of perioperative ischemic complications. We aimed to evaluate modifiable stroke risk factors in children undergoing surgical revascularization for moyamoya.

MATERIALS AND METHODS

In this exploratory, single-center, retrospective cohort study, medical records of pediatric patients undergoing surgical revascularization for moyamoya arteriopathy at our center between 2003 and 2021 were reviewed. Candidate modifiable risk factors were analyzed for association with perioperative stroke, defined as ischemic stroke ≤7 days after surgery.

RESULTS

We analyzed 53 surgeries, consisting of 39 individual patients undergoing indirect surgical revascularization of 74 hemispheres. Perioperative ischemic stroke occurred following five surgeries (9.4%). There were no instances of hemorrhagic stroke. Larger pre-to-postoperative decreases in hemoglobin (OR 3.90, p=0.017), hematocrit (OR 1.69, p=0.012) and blood urea nitrogen (OR 1.83, p=0.010) were associated with increased risk of perioperative ischemic stroke. Weight-adjusted intraoperative blood loss was not associated with risk of perioperative ischemic stroke (OR 0.94, p=0.796). Among children with sickle cell disease, all of whom underwent exchange transfusion within one week prior to surgery, none experienced perioperative stroke.

CONCLUSIONS

Decreases in hemoglobin, hematocrit, and blood urea nitrogen between the preoperative and postoperative periods are associated with increased risk of perioperative stroke. These novel findings suggest that dilutional anemia, possibly due to standardly administered hyperhydration, may increase the risk of perioperative stroke in some children with moyamoya. Further work optimizing both mean arterial pressure and oxygen-carrying capacity in these patients, including consideration of alternative blood transfusion thresholds, is necessary.

Moyamoya Angiopathy: An Underdiagnosed Cause of Ischemic Stroke in a Tunisian Pediatric Cohort

BACKGROUND

Moyamoya angiopathy is a rare cerebral vasculopathy and an underdiagnosed cause of arterial ischemic stroke in children. We aim to report the clinical and radiological presentations in a Tunisian pediatric cohort.

METHODS

We identified moyamoya angiopathy in pediatric patients managed at the Child Neurology Department of Hedi Chaker Sfax University Hospital between 2008 and 2020 and reviewed their clinical and radiological data as well as their evolutionary profile.

RESULTS

We collected 14 patients with median age 40.6 months and a female predominance (sex ratio of 0.75). An arterial ischemic stroke (AIS) revealed the disease in all patients, with the major symptom being a motor deficit. Symptoms related to a transient ischemic attack before the diagnostic consultation were reported in four patients. Carotid territory was, clinically and radiologically, the most frequently involved. Brain magnetic resonance imaging with angiography was performed in 12 patients confirming the diagnosis by revealing the development of collateral vessels. All the investigations concluded to moyamoya disease in 57.2% and moyamoya syndrome in 42.8%. The latter was related to Down syndrome in five patients and neurofibromatosis type 1 in one patient. With a mean follow-up of 2.35 years, two patients had at least two more AISs during the first two years following diagnosis and 42.8% of patients were diagnosed with vascular or poststroke epilepsy. Full recovery was noted in 14.3% of cases.

CONCLUSIONS

Moyamoya angiopathy in children is a serious condition that needs to be recognized due to the high risk of recurrent ischemic strokes.

Moyamoya disease in an adolescent with subarachnoid hemorrhage: a case report

PURPOSE/AIM OF THE STUDY

This study aims to present a case of Moyamoya disease (MMD) in an adolescent who experienced a subarachnoid hemorrhage (SAH). The purpose is to underscore the importance of considering MMD as a potential cause of SAH in adolescents, particularly in the absence of common causes such as trauma or aneurysmal rupture. The case further highlights the significance of early identification and appropriate management to prevent further complications and improve patient outcomes.

MATERIALS AND METHODS

The diagnosis was initially based on findings from a CT angiography and later confirmed through magnetic resonance angiography (MRA) and magnetic resonance imaging (MRI).

RESULTS

The case study demonstrates the effectiveness of utilizing MRA and MRI in diagnosing MMD in adolescents. It emphasizes the challenges in areas with limited resources where advanced imaging techniques like digital subtraction angiography (DSA) may not be readily accessible or affordable. The gold standard for MMD diagnosis, DSA, is acknowledged, but the study underscores the importance of alternative imaging methods in resource-constrained settings.

CONCLUSION

In conclusion, this case underscores the importance of considering Moyamoya disease as a potential etiology for subarachnoid hemorrhage in adolescents, particularly when common causes are absent. The study highlights the crucial role of MRA and MRI in the diagnosis of MMD, emphasizing their significance in areas with limited resources. Early identification and appropriate management are essential for preventing complications and improving patient outcomes, acknowledging the challenges associated with the accessibility of gold standard diagnostic techniques in certain settings.

Moyamoya Disease: Clinical and Radiological Characteristics in Adult Greek Patients

BACKGROUND AND PURPOSE

The aim of our study is to present, for the first time, the clinical, radiological, and neurocognitive characteristics of Greek adult patients with Moyamoya disease (MMD).

METHODS

We analyzed prospectively collected data of 12 patients referred to our department from 2004 to 2019. All patients underwent a thorough diagnostic work up, including extensive clinical, neuroradiological, and neurocognitive assessment.

RESULTS

Our study population consisted of 7 females and the median age at the time of the diagnosis was 43.5 years. No patient had a positive family history of the disease and roughly 50% were hypertensives. Ten patients presented with transient or permanent cerebrovascular ischemia and two patients suffered from hemorrhagic complications. The median NIHSS was 7.5 (0-23) and clinical status remained stable during follow-up with conservative treatment in most of the patients. The majority (83.3%) had bilateral disease confirmed by DSA. All lesions exclusively affected the anterior circulation, with 50% of patients presenting with stenoocclusive changes. No aneurysm or AVM were revealed. The most common neurocognitive deficits were in the executive and language domains.

CONCLUSIONS

Our MMD patients had a later onset of the disease and an absence of familial occurrence. The most common manifestation was ischemia, transient or permanent, and all lesions affected the anterior circulation, whereas no vascular malformations (AVM, aneurysms) were demonstrated in brain imaging. These findings in Greek patients imply a probable different, Mediterranean phenotype.

A dual-center validation of the PIRAMD scoring system for assessing the severity of ischemic Moyamoya disease

Background

Prior Infarcts, Reactivity, and Angiography in Moyamoya Disease (PIRAMD) is a recently proposed imaging-based scoring system that incorporates the severity of disease and its impact on parenchymal hemodynamics in order to better support clinical management and evaluate response to intervention. In particular, PIRAMD may have merit in identifying symptomatic patients that may benefit most from revascularization. Our aim was to validate the PIRAMD scoring system.

Methods

Patients with ischemic Moyamoya disease, who underwent catheter angiographic [modified Suzuki Score (mSS) and collateralization status], morphological MRI and a parenchymal hemodynamic evaluation with blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) at two transatlantic centers, were retrospectively included. The primary outcome was the presence of neurological symptoms. The diagnostic capacity of each PIRAMD feature alone was evaluated, as well as combined and the inter-institutional differences of each parameter were evaluated.

Results

Seventy-two hemispheres of 38 patients were considered for analysis, of which 39 (54%) were classified as symptomatic. The presence of a prior infarct had the highest odds ratio [odds ratio (OR) =24; 95% CI: 6.7-87.2] for having neurological symptoms, followed by impaired CVR (OR =17; 95% CI: 5-62). No inter-institutional differences in the odds ratios or area under the curve (AUC) were found for any study parameter. The PIRAMD score had an AUC of 0.88 (95% CI: 0.80-0.96) with a similar AUC for the PIRAMD grading score.

Conclusions

Our multicentric validation of the recently published PIRAMD scoring system was highly effective in rating the severity of ischemic Moyamoya disease with excellent inter-institutional agreement. Future studies should investigate the prognostic value of this novel imaging-based score in symptomatic patients with Moyamoya disease.

Evaluation of single-delay arterial spin labeling-based spatial coefficient of variation and histogram-based parameters in relation to cerebrovascular reserve in patients with Moyamoya disease

Introduction

Single-delay Arterial Spin Labeling (ASL)-based spatial coefficient of variation (CoV_CBF) has been suggested as a measure of hemodynamic disturbance in patients with cerebrovascular diseases. However, spatial CoV_CBF and other histogram-based parameters such as skewness and kurtosis and the volume of the arterial transit time artefact (ATA_vol), has not been evaluated in patients with MMD nor against cerebrovascular reserve (CVR). The aim of this study was to assess whether any associations between spatial CoV_CBF, skewness, kurtosis, and ATA_vol are present and to analyze any potential associations with CVR, derived from single-delay ASL in patients with MMD.

Methods

Fifteen MMD patients were included before or after revascularization surgery. Cerebral blood flow (CBF) maps were acquired using pseudo-continuous ASL before, and 5, 15, and 25 min after an intravenous acetazolamide injection. CVR_max was defined as the highest percentual increase in CBF at any of the three post-injection time points. A vascular territory template was spatially normalized to each patient, including the bilateral anterior, middle, and posterior cerebral arteries. All affected anterior and middle cerebral artery regions and all unaffected posterior cerebral artery regions were included, based on Suzuki grading by digital subtraction angiography.

Results

Significant differences between affected and unaffected regions were found for CBF, CVR_max, and ATA_vol. No association was found between CVR_max and any other parameter. High correlations were found between spatial CoV_CBF, skewness and ATA_vol.

Conclusion

Spatial CoV_CBF derived from single-delay ASL does not correlate with CVR in patients with MMD. Moreover, skewness and kurtosis did not provide additional information of clinical value.

Advances in Management of the Stroke Etiology One-Percenters

PURPOSE OF REVIEW

Uncommon causes of stroke merit specific attention; when clinicians have less common etiologies of stoke in mind, the diagnosis may come more easily. This is key, as optimal management will in many cases differs significantly from "standard" care.

RECENT FINDINGS

Randomized controlled trials (RCT) on the best medical therapy in the treatment of cervical artery dissection (CeAD) have demonstrated low rates of ischemia with both antiplatelet and vitamin K antagonism. RCT evidence supports the use of anticoagulation with vitamin K antagonism in "high-risk" patients with antiphospholipid antibody syndrome (APLAS), and there is new evidence supporting the utilization of direct oral anticoagulation in malignancy-associated thrombosis. Migraine with aura has been more conclusively linked not only with increased risk of ischemic and hemorrhagic stroke, but also with cardiovascular mortality. Recent literature has surprisingly not provided support the utilization of L-arginine in the treatment of patients with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS); however, there is evidence at this time that support use of enzyme replacement in patients with Fabry disease. Additional triggers for reversible cerebral vasoconstriction syndrome (RCVS) have been identified, such as capsaicin. Imaging of cerebral blood vessel walls utilizing contrast-enhanced MRA is an emerging modality that may ultimately prove to be very useful in the evaluation of patients with uncommon causes of stroke. A plethora of associations between cerebrovascular disease and COVID-19 have been described. Where pertinent, authors provide additional tips and guidance. Less commonly encountered conditions with updates in diagnosis, and management along with clinical tips are reviewed.

Moyamoya-Like Vasculopathy and Orbital Trauma: An Association

An Asian man in his 20s developed asymptomatic ipsilateral moyamoya-like vascular changes following orbital and head trauma. An ipsilateral traumatic optic neuropathy with extensive optic cupping ensued. The complex embryology of the ocular vascular development is reviewed as having a potential causative role in the intracranial carotid vasculopathy.

Same-day versus staged revascularization of bilateral moyamoya arteriopathy in pediatric patients

PURPOSE

To compare the outcomes of conducting left and right hemisphere surgical revascularization on the same day versus different days for bilateral pediatric moyamoya arteriopathy patients.

METHODS

We retrospectively analyzed mortality, stroke, and transient neurologic event (TNE) rates in North American bilateral pediatric moyamoya arteriopathy patients who underwent bilateral cerebral revascularization.

RESULTS

A total of 38 pediatric (≤ 18 years old) patients at our institution underwent bilateral cerebral revascularization for moyamoya arteriopathy. Of these patients, 24 (63.2%) had both operations on the same day and 14 (36.8%) had the two operations on different days. The average length of stay for patients who underwent same-day bilateral revascularization was 6.9 ± 2.0 days and the average length of stay for each operation for patients who underwent staged bilateral revascularization was 4.5 ± 1.4 days, p = 0.001. While there were 7 (14.6%) postoperative strokes in patients who had both hemispheres revascularized on the same day, 0 (0%) strokes occurred in hemispheres after they had been operated on in the staged cohort, p = 0.042. Additionally, the postoperative stroke-free survival time in the ipsilateral hemisphere and TNE-free survival time were significantly longer in patients in the staged revascularization cohort.

CONCLUSION

Same-day bilateral revascularization was associated with longer length of stay per operation, higher rate of ipsilateral stroke, and shorter postoperative TNE-free and stroke-free survival time in the revascularized hemisphere.

Whole-exome sequencing in moyamoya patients of Northern-European origin identifies gene variants involved in Nitric Oxide metabolism: A pilot study

Introduction

Moyamoya disease (MMD) is a chronic cerebrovascular steno-occlusive disease of largely unknown etiology. Variants in the RNF213 gene are strongly associated with MMD in East-Asia. In MMD patients of Northern-European origin, no predominant susceptibility variants have been identified so far.

Research question

Are there specific candidate genes associated with MMD of Northern-European origin, including the known RNF213 gene? Can we establish a hypothesis for MMD phenotype and associated genetic variants identified for further research?

Material and methods

Adult patients of Northern-European origin, treated surgically for MMD at Oslo University Hospital between October 2018 to January 2019 were asked to participate. WES was performed, with subsequent bioinformatic analysis and variant filtering. The selected candidate genes were either previously reported in MMD or known to be involved in angiogenesis. The variant filtering was based on variant type, location, population frequency, and predicted impact on protein function.

Results

Analysis of WES data revealed nine variants of interest in eight genes. Five of those encode proteins involved in nitric oxide (NO) metabolism: NOS3, NR4A3, ITGAV, GRB7 and AGXT2. In the AGXT2 gene, a de novo variant was detected, not previously described in MMD. None harboured the p.R4810K missense variant in the RNF213 gene known to be associated with MMD in East-Asian patients.

Discussion and conclusion

Our findings suggest a role for NO regulation pathways in Northern-European MMD and introduce AGXT2 as a new susceptibility gene. This pilot study warrants replication in larger patient cohorts and further functional investigations.

Evaluation of vessel-wall contrast-enhancement on high-resolution MRI in European patients with Moyamoya disease

OBJECTIVES

Data regarding MR vessel-wall imaging (VWI) in patients with Moyamoya disease (MMD) is sparse, particularly in non-asian cohorts. We contribute data regarding the frequency of vessel wall contrast-enhancement (VW-CE) and its potential clinical significance in a European patient group.

MATERIALS AND METHODS

Patients with a diagnosis of MMD who were examined by VWI were included in the study. VW-CE of stenoocclusive lesions of the terminal internal carotid artery and/or its proximal branches was rated qualitatively. Changes of VW-CE on available follow-up were recorded. VW-CE was correlated with diffusion-restricted lesions and magnetic resonance angiography (MRA) findings.

RESULTS

Eleven patients (eight female, three male) were included. Twenty-eight stenoocclusive lesions were analyzed, of which 16 showed VW-CE (57.1%). VW-CE was mostly concentric (n=15), rather than eccentric (n=1). In all three patients in whom follow-up VWI was available, changes of VW-CE were documented. Diffusion-restricted lesions were more frequently related to stenoocclusive lesions with VW-CE (n=9) than without VW-CE (n=2), bordering statistical significance. The affected arteries were assessed as stenotic and as occluded in 14 cases each and VW-CE was seen significantly more often in stenotic (n=12) than in occluded arteries (n=4). No correlation was found between the presence of VW-CE and moyamoya stages determined by MRA.

CONCLUSIONS

Our data suggest that concentric VW-CE is a relatively frequent finding in European MMD patients. VW-CE may change over time and occur in certain stages, possibly representing "active stenosing". Larger studies are needed to validate these findings and determine the clinical relevance of VW-CE in MMD.

Sex differences in cardiovascular disease and dysregulation in Down syndrome

This meta-analysis, which consisted of a scoping review and retrospective medical record review, is focused on potential sex differences in cardiovascular diseases in patients with Down syndrome. We limited our review to peer-reviewed, primary articles in the English language, in the PubMed and Web of Science databases from 1965 to 2021. Guidelines for scoping reviews were followed throughout the process. Four categorical domains were identified and searched using additional keywords: 1) congenital heart disease, 2) baseline physiology and risk factors, 3) heart disease and hypertension, and 4) stroke and cerebrovascular disease. Articles were included if they reported male and female distinct data, participants with Down syndrome, and one of our keywords. The retrospective medical record review was completed using 75 participating health care organizations to identify the incidence of congenital and cardiovascular diseases and to quantify cardiovascular risk factors in male and female patients. Female patients with Down syndrome are at higher risk of hypertension, ischemic heart disease, and cerebrovascular disease. The risk of congenital heart disease is higher in males with Down syndrome at all ages included in our analyses. Some of the male-to-female sex differences in cardiovascular disease risk in the general patient population are not present, or reversed in the Down syndrome population. This information should be considered for future investigations and ongoing patient care.NEW & NOTEWORTHY In patients with Down syndrome (DS), CHD is the leading cause of death <20 yr old and cardiovascular disease is a leading cause of death in individuals >20 yr old. Men with DS live longer than women. It is unknown if sex differences are present in cardiovascular disease and dysregulation in DS across the lifespan. We observed higher risk of hypertension, ischemic heart disease, and cerebrovascular disease in females and a higher risk of CHD in males with DS.

Practice variability in the perioperative management of pediatric moyamoya disease in North America

BACKGROUND

Revascularization surgery decreases the long-term risk of stroke in children with moyamoya but carries an increased risk of perioperative ischemic events. Evidence-based approaches to safe perioperative management of children with moyamoya are limited. We aimed to understand practice variability in perioperative moyamoya care.

METHODS

Neurologists, neurosurgeons, and intensivists practicing in North America with expertise in perioperative pediatric moyamoya care participated in a 138-item anonymous survey focused on interdisciplinary perioperative care surrounding indirect revascularization surgery.

RESULTS

Many perioperative care practices vary substantially between participants. Timing of resumption of antiplatelet therapy postoperatively, choice of sedative agents and vasopressors, goal blood pressures, rate and duration of intravenous fluid administration, and red blood cell transfusion thresholds are among the most variable practices.

CONCLUSIONS

This practice variability survey highlights several important knowledge gaps and areas of equipoise that should be targets for future investigation and consensus-building efforts.

Moyamoya Vasculopathy in Neurofibromatosis Type 1 Pediatric Patients: The Role of Rare Variants of RNF213

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder caused by mutations in NF1 gene, coding for neurofibromin 1. NF1 can be associated with Moyamoya disease (MMD), and this association, typical of paediatric patients, is referred to as Moyamoya syndrome (MMS). MMD is a cerebral arteriopathy characterized by the occlusion of intracranial arteries and collateral vessel formation, which increase the risk of ischemic and hemorrhagic events. RNF213 gene mutations have been associated with MMD, so we investigated whether rare variants of RNF213 could act as genetic modifiers of MMS phenotype in a pediatric cohort of 20 MMS children, 25 children affected by isolated MMD and 47 affected only by isolated NF1. By next-generation re-sequencing (NGS) of patients' DNA and gene burden tests, we found that RNF213 seems to play a role only for MMD occurrence, while it does not appear to be involved in the increased risk of Moyamoya for MMS patients. We postulated that the loss of neurofibromin 1 can be enough for the excessive proliferation of vascular smooth muscle cells, causing Moyamoya arteriopathy associated with NF1. Further studies will be crucial to support these findings and to elucidate the possible role of other genes, enhancing our knowledge about pathogenesis and treatment of MMS.

Biallelic variants in NOS3 and GUCY1A3, the two major genes of the nitric oxide pathway, cause moyamoya cerebral angiopathy

BACKGROUND

Moyamoya angiopathy (MMA) is a rare cerebrovascular condition leading to stroke. Mutations in 15 genes have been identified in Mendelian forms of MMA, but they explain only a very small proportion of cases. Our aim was to investigate the genetic basis of MMA in consanguineous patients having unaffected parents in order to identify genes involved in autosomal recessive MMA.

METHODS

Exome sequencing (ES) was performed in 6 consecutive consanguineous probands having MMA of unknown etiology. Functional consequences of variants were assessed using western blot and protein 3D structure analyses.

RESULTS

Causative homozygous variants of NOS3, the gene encoding the endothelial nitric oxide synthase (eNOS), and GUCY1A3, the gene encoding the alpha1 subunit of the soluble guanylate cyclase (sGC) which is the major nitric oxide (NO) receptor in the vascular wall, were identified in 3 of the 6 probands. One NOS3 variant (c.1502 + 1G > C) involves a splice donor site causing a premature termination codon and leads to a total lack of eNOS in endothelial progenitor cells of the affected proband. The other NOS3 variant (c.1942 T > C) is a missense variant located into the flavodoxine reductase domain; it is predicted to be destabilizing and shown to be associated with a reduction of eNOS expression. The GUCY1A3 missense variant (c.1778G > A), located in the catalytic domain of the sGC, is predicted to disrupt the tridimensional structure of this domain and to lead to a loss of function of the enzyme. Both NOS3 mutated probands suffered from an infant-onset and severe MMA associated with posterior cerebral artery steno-occlusive lesions. The GUCY1A3 mutated proband presented an adult-onset MMA associated with an early-onset arterial hypertension and a stenosis of the superior mesenteric artery. None of the 3 probands had achalasia.

CONCLUSIONS

We show for the first time that biallelic loss of function variants in NOS3 is responsible for MMA and that mutations in NOS3 and GUCY1A3 are causing fifty per cent of MMA in consanguineous patients. These data pinpoint the essential role of the NO pathway in MMA pathophysiology.

Diffusion-Weighted Magnetic Resonance Imaging Demonstrates White Matter Alterations in Watershed Regions in Children With Moyamoya Without Stroke or Silent Infarct

BACKGROUND

Moyamoya is a disease with progressive cerebral arterial stenosis leading to stroke and silent infarct. Diffusion-weighted magnetic resonance imaging (dMRI) studies show that adults with moyamoya have significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) compared with controls, which raises concern for unrecognized white matter injury. Children with moyamoya have significantly lower FA and higher MD in their white matter compared with controls. However, it is unknown which white matter tracts are affected in children with moyamoya.

METHODS

We present a cohort of 15 children with moyamoya with 24 affected hemispheres without stroke or silent infarct compared with 25 controls. We analyzed dMRI data using unscented Kalman filter tractography and extracted major white matter pathways with a fiber clustering method. We compared the FA, MD, AD, and RD in each segmented white matter tract and combined white matter tracts found within the watershed region using analysis of variance.

RESULTS

Age and sex were not significantly different between children with moyamoya and controls. Specific white matter tracts affected included inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, superior longitudinal fasciculus, thalamofrontal, uncinate fasciculus, and arcuate fasciculus. Combined watershed region white matter tracts in children with moyamoya had significantly lower FA (-7.7% ± 3.2%, P = 0.02) and higher MD (4.8% ± 1.9%, P = 0.01) and RD (8.7% ± 2.8%, P = 0.002).

CONCLUSIONS

Lower FA with higher MD and RD is concerning for unrecognized white matter injury. Affected tracts were located in watershed regions suggesting that the findings may be due to chronic hypoperfusion. These findings support the concern that children with moyamoya without overt stroke or silent infarction are sustaining ongoing injury to their white matter microstructure and provide practitioners with a noninvasive method of more accurately assessing disease burden in children with moyamoya.

Early Experience of Surgical Planning for STA-MCA Bypass Using Virtual Reality

OBJECTIVE

To describe our experience with VR-based preoperative planning of STA-MCA bypass.

BACKGROUND

The superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass requires precise preoperative planning, and 3D Virtual Reality (VR) models have been recently utilized to optimize planning of STA-MCA bypass.

METHODS

Patients from August 2020 to February 2022 were analyzed. For the VR group, using 3D models from patients' preoperative CTA, VR was used to locate donor vessels, potential recipient, anastomosis sites, and plan craniotomy, which were referenced throughout surgery. CTA or DSA were used to plan the control group. Procedure time, bypass patency, craniotomy size, and postoperative complication rates were assessed.

RESULTS

The VR group included 17 patients (13 females; 49±14 years) with Moyamoya disease (MMD) (76.5%) and/or ischemic stroke (29.4%). Control group included 13 patients (8 females; 49±12 years) with MMD (92.3%) and/or ischemic stroke (7.3%). For all patients, the preoperatively planned donor and recipient branches were effectively translated intraoperatively. There was no significant difference in procedure time and craniotomy size between the groups. Bypass patency was 94.1% (VR:16/17) and 84.6% (Control:11/13). There were no permanent neurological deficits in either group.

CONCLUSION

Based on our early experience, VR serves as a useful, interactive presurgical planning tool by enhancing visualization of the spatial relationship between STA and MCA without compromising any surgical results.

Understanding how the primary endpoint impacts the interpretation of trial results: The Japanese Adult Moyamoya bypass trial

BACKGROUND

The meaning of a clinical trial depends to a large extent on the choice of the primary outcome measure, which can be explanatory or pragmatic.

METHODS

We review the Japanese Adult Moyamoya (JAM) trial, that compared surgical extracranial to intracranial (EC-IC) bypass and medical management of hemorrhagic moyamoya disease. We also review some principles which guide the selection of the primary trial endpoint.

DISCUSSION

The main component of the primary outcome measure in JAM was rebleeding, a surrogate outcome that allowed investigators to demonstrate that surgical bypass had causal efficacy. However, the number of patients with a poor outcome, defined as those with a modified Rankin score (mRS)>2, would have been a more pragmatic choice. Unfortunately, the trial was too small to show that patients benefited from surgery.

CONCLUSION

The JAM trial showed that EC-IC bypass can decrease rebleeding in moyamoya patients, but whether patients have better outcomes with surgery remains uncertain. Hard pragmatic clinical primary outcome measures are necessary to guide surgical care.

Internal Carotid Artery Stenosis: A Surgical Mouse Model to Study Moyamoya Syndrome

Moyamoya is a cerebrovascular condition that predisposes affected patients to stroke and is characterized as the progressive stenosis of the internal carotid artery (ICA) and compensatory development of collaterals at the base of the brain. Patients with moyamoya syndrome also present with comorbidities such as various autoimmune diseases and coagulopathies. We developed a surgical method using micro-coils to induce ICA-specific stenosis in mice, which induces moyamoya-like vasculopathies. An advantage of this surgical model of hypoperfusion is that it can be combined with other comorbid models to investigate pathologies associated with moyamoya syndrome.

Atrophy in subcortical gray matter in adult patients with moyamoya disease

BACKGROUND

Acute cerebrovascular accidents, long-term hypoperfusion, and/or remote neuronal degeneration may lead to structural alterations in patients with moyamoya disease (MMD). This study sought to comprehensively investigate the distribution characteristics of subcortical gray matter volume and their correlations with angiographic changes in the intracranial artery in patients with MMD.

METHOD

One hundred forty-two patients with MMD and 142 age- and sex-matched healthy controls underwent 3-dimensional high-resolution structural magnetic resonance imaging. Volumes of subcortical gray matter and subregions of the hippocampus and amygdala were calculated, and the degree of stenosis/occlusion of intracranial arteries in patients with MMD was evaluated on MR angiography.

RESULTS

Volume reductions in the thalamus, caudate, putamen, hippocampus, amygdala, pallidum, and nucleus accumbens were found in patients with MMD. Hippocampal subfields and amygdala subnuclei in patients with MMD showed distinct vulnerability, and morphological alterations in specific subregions were more obvious than in the whole hippocampus/amygdala. Volume loss in several subcortical areas was related to disease duration and intracranial arterial changes.

CONCLUSIONS

Our findings revealed structural alteration patterns of subcortical gray matter in MMD. The specific atrophy in subregions of the hippocampus and the amygdala suggested potential cognitive and affective impairments in MMD, which warrants further investigation. Chronic cerebral hemodynamic alterations in MMD may play a pivotal role in morphological changes in subcortical areas.

Ultrasonic hemodynamic changes of superficial temporal artery graft in different angiogenesis outcomes of Moyamoya disease patients treated with combined revascularization surgery

Objective

Combined bypass is commonly used in adult Moyamoya disease (MMD) for revascularization purposes. The blood flow from the external carotid artery system supplied by the superficial temporal artery (STA), middle meningeal artery (MMA), and deep temporal artery (DTA) can restore the impaired hemodynamics of the ischemic brain. In this study we attempted to evaluate the hemodynamic changes of the STA graft and predict the angiogenesis outcomes in MMD patients after combined bypass surgery by using quantitative ultrasonography.

Methods

We retrospectively studied Moyamoya patients who were treated by combined bypass between September 2017 and June 2021 in our hospital. We quantitatively measured the STA with ultrasound and recorded the blood flow, diameter, pulsatility index (PI) and resistance index (RI) to assess graft development preoperatively and at 1 day, 7 days, 3 months, and 6 months after surgery. All patients received both pre- and post- operative angiography evaluation. Patients were divided into either well- or poorly-angiogenesis groups according to the transdural collateral formation status on angiography at 6 months after surgery (W group or P group). Patients with matshushima grade A or B were divided into W group. Patients with matshushima grade C were divided into P group, indicating a poor angiogenesis development.

Results

A total of 52 patients with 54 operated hemispheres were enrolled, including 25 men and 27 women with an average age of 39 ± 14.3 years. Compared to preoperative values, the average blood flow of an STA graft at day 1 postoperation increased from 16.06 ± 12.47 to 117.47± 73.77 (mL/min), diameter increased from 1.14 ± 0.33 to 1.81 ± 0.30 (mm), PI dropped from 1.77 ± 0.42 to 0.76 ± 0.37, and RI dropped from 1.77 ± 0.42 to 0.50 ± 0.12. According to the Matsushima grade at 6 months after surgery, 30 hemispheres qualified as W group and 24 hemispheres as P group. Statistically significant differences were found between the two groups in diameter (p = 0.010) as well as flow (p = 0.017) at 3 months post-surgery. Flow also remained significantly different at 6 months after surgery (p = 0.014). Based on GEE logistic regression evaluation, the patients with higher levels of flow post-operation were more likely to have poorly-compensated collateral. ROC analysis showed that increased flow of ≥69.5 ml/min (p = 0.003; AUC = 0.74) or a 604% (p = 0.012; AUC = 0.70) increase at 3 months post-surgery compared with the pre-operative value is the cut-off point which had the highest Youden's index for predicting P group. Furthermore, a diameter at 3 months post-surgery that is ≥0.75 mm (p = 0.008; AUC = 0.71) or 52% (p =0.021; AUC = 0.68) wider than pre-operation also indicates a high risk of poor indirect collateral formation.

Conclusions

The hemodynamic of the STA graft changed significantly after combined bypass surgery. An increased flow of more than 69.5 ml/min at 3 months was a good predictive factor for poor neoangiogenesis in MMD patients treated with combined bypass surgery.

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.

Combined direct and indirect superficial temporal artery-to-middle cerebral artery bypass with a hinged bone flap: how I do it

BACKGROUND

Superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass is a critical treatment for moyamoya disease and steno-occlusive cerebrovascular disease. Combined bypass (direct + indirect) optimizes the chance of durable flow augmentation but can complicate wound closure from tissue disruption.

METHODS

We describe our technique for combined direct and indirect (encephaloduromyosynangiosis; EDAMS) STA-MCA bypass using a hinged bone flap. In addition to a direct bypass, EDAMS provides multiple sources for indirect revascularization. The hinged bone flap gently approximates the muscle and pia for secondary vascular ingrowth.

CONCLUSIONS

Combined STA-MCA bypass with a hinged bone flap safely maximizes revascularization potential.

Risk Factors and Imaging Biomarkers Associated With Perioperative Stroke in Pediatric Moyamoya Arteriopathy

Patients with moyamoya arteriopathy are at high risk for developing ischemic stroke in the perioperative period. We sought to evaluate whether preoperative clinical and neuroimaging biomarkers are associated with postoperative stroke and transient ischemic attack in children with moyamoya following revascularization surgery. We performed a retrospective chart review of pediatric patients who underwent revascularization surgery for moyamoya in the last 15 years. Fifty-three patients who underwent 69 surgeries met the inclusion criteria. We recorded clinical predictors of stroke or transient ischemic attack within 7 days following surgery. We used Suzuki stage and Composite Cerebrovascular Stenosis Score to analyze neuroimaging. Significant risk factors for developing postoperative stroke or transient ischemic attack were younger age at surgery (P = .004) and transient ischemic attack less than 1 month prior to surgery (P < .001). Children under 5 and those with recent preoperative ischemic events should be the focus of investigation to evaluate modifiable risk factors and targeted interventions.

Seizures, Epilepsy, and Electroencephalography Findings in Pediatric Moyamoya Arteriopathy: A Scoping Review

BACKGROUND

Although seizures are known to occur in children with moyamoya arteriopathy, data regarding characteristics, prevalence, and predictive factors for their development are less established. This study aimed to systematically review literature addressing seizures, epilepsy, and electroencephalography findings in the pediatric moyamoya population.

METHODS

A scoping review was performed by searching PubMed and Ovid:Embase databases for articles that described seizures, epilepsy, and electroencephalography findings in patients aged 0 to 21 years with moyamoya arteriopathy.

RESULTS

The search yielded 43 total articles that addressed the following topics in childhood moyamoya: seizures as the presenting symptom, epilepsy characteristics and management, characteristic electroencephalography findings including rebuildup with discussion of proposed mechanisms, and potential predictive clinical factors for the development of seizures preoperatively and the persistence of epilepsy postoperatively. In the reviewed literature, 9% to 19% of children with moyamoya had epilepsy, with over half of the cases lacking radiographic evidence of ischemia. Young age was the most consistent clinical factor associated with both seizures as the presenting symptom and with moyamoya-related epilepsy. Multiple studies report that seizures, electroencephalographic background abnormalities, and the rebuildup phenomenon improve after successful revascularization surgery.

CONCLUSIONS

This scoping review provides a thorough investigation of the literature available to date on the clinical features of seizures in the pediatric moyamoya population. Literature on this topic is scarce and further studies assessing predictive factors for the development of epilepsy, prognosis as a result of having seizures, and seizure management in this population will help to fill existing knowledge gaps.

RNF213 loss of function reshapes vascular transcriptome and spliceosome leading to disrupted angiogenesis and aggravated vascular inflammatory responses

RNF213 gene mutations are the cause behind Moyamoya disease, a rare cerebrovascular occlusive disease. However, the function of RNF213 in the vascular system and the impact of its loss of function are not yet comprehended. To understand RNF23 function, we performed gene knockdown (KD) in vascular cells and performed various phenotypical analysis as well as extensive transcriptome and epitranscriptome profiling. Our data revealed that RNF213 KD led to disrupted angiogenesis in HUVEC, in part due to downregulation of DNA replication and proliferation pathways. Furthermore, HUVEC cells became sensitive to LPS induced inflammation after RNF213 KD, leading to retarded cell migration and enhanced macrophage transmigration. This was evident at the level of transcriptome as well. Interestingly, RNF213 led to extensive changes in mRNA splicing that were not previously reported. In vascular smooth muscle cells (vSMCs), RNF213 KD led to alteration in cytoskeletal organization, contractility, and vSMCs function related pathways. Finally, RNF213 KD disrupted endothelial-to-vSMCs communication in co-culture models. Overall, our results indicate that RNF213 KD sensitizes endothelial cells to inflammation, leading to altered angiogenesis. Our results shed the light on the important links between RNF213 mutations and inflammatory/immune inducers of MMD and on the unexplored role of epitranscriptome in MMD.

Modified pedicled temporoparietal fascial flap combined revascularization in adult moyamoya angiopathy

Background

Pedicled temporoparietal fascial flaps (TPFF), which are flexible, thin, and highly vascularized, have been tried for the moyamoya angiopathy (MMA) treatment. To reduce postoperative complications and improve prognosis, we performed surgical modification and followed up to observe the efficacy.

Methods

From February 2018 and June 2022, the clinical data of 31 adult MMA patients who underwent the modified TPFF combined revascularization were collected. The clinical outcomes and complications of the patients were recorded until the cut-off date of follow-up. The primary endpoints were the magnetic resonance perfusion (MRP), modified Rankin Scale (mRS) scores, and Matsushima Grade; the secondary endpoints were the clinical symptom outcome and Postoperative complications. Descriptive statistics and rank sum test to assess the therapeutic effect of the modified TPFF combined revascularization for adult MMA treatment.

Results

The clinical symptoms of MMA were alleviated in 26 patients and disappeared in five. In all patients, MRP showed improvement in cerebral perfusion on the operated side, and no deterioration or new cerebral infarction occurred during follow-up. Postoperative digital subtraction angiography (DSA) showed that the anastomotic site was patent, and the MMA collateral was decreased in all patients. Only 1 case (3%) of Matsushima grade C showed poor collateral compensation. The admission mRS score (1.54±0.66) of the ischemic MMA was significantly reduced compared with ≥6 months postoperatively (0.54±0.72, P<0.01). The admission mRS score (0.57±0.53) of the hemorrhagic MMA was reduced compared with ≥6 months postoperatively (0, P<0.05). Postoperative complications included epileptic seizures in 2 cases, a cerebral hyper-perfusion syndrome in 2 cases, intracranial rebleeding in 2 cases, skin necrosis in 1 case, and skin maceration in 1 case.

Conclusions

Modified TPFF combined revascularization might be a feasible and safe surgical technique for MMA, but it is still necessary to increase the sample size and extend the follow-up time to evaluate its efficacy. Ischemic MMA may have a more significant prognostic benefit than hemorrhagic MMA by this surgery.

Timing of Revascularization in Ischemic Moyamoya Disease: Association of Early Versus Delayed Surgery with Perioperative and Long-Term Outcomes

OBJECTIVE

Patients with nmoyamoya disease (MMD) who present primarily with ischemic stroke are known to have greater rates of perioperative strokes as compared with those who present with nonstroke symptoms. The optimal timing for revascularization for these patients remains unclear.

METHODS

From 1994 to 2015, 91 patients with MMD presented with signs and symptoms of an acute ischemic stroke with diffusion restriction correlate on magnetic resonance imaging, and these patients were subdivided into those who underwent early revascularization (<90 days from last stroke), versus those who underwent delayed revascularization (≥90 days after last stroke), based on evidence that most neurological recovery after stroke occurs during the first three months. Perioperative and long-term outcomes were compared between the 2 surgical cohorts.

RESULTS

In total, 27 patients underwent early revascularization, and 64 patients underwent delayed revascularization. Patients who underwent early revascularization had a statistically greater rate of perioperative stroke (P = 0.04) and perioperative mortality (P = 0.03), and overall complication rate (P = 0.049). At last follow-up of 5.2 ± 4.3 years, patients who underwent delayed revascularization had a lower mortality rate (P = 0.01) and a lower overall postoperative stroke incidence (P = 0.002). As a function of time, patients with MMD undergoing delayed revascularization had a statistically higher length of stroke-free survival (P = 0.005).

CONCLUSIONS

Patients with MMD who present with ischemic stroke are more likely to have perioperative strokes, overall perioperative complications, worse long-term mortality rates, and lower rates of stroke-free survival if revascularization surgery occurred within 90 days of last stroke.

Fronto-Parietal and White Matter Haemodynamics Predict Cognitive Outcome in Children with Moyamoya Independent of Stroke

Moyamoya disease is a major arteriopathy characterised by progressive steno-occlusion of the arteries of the circle of Willis. Studies in adults with moyamoya suggest an association between abnormal fronto-parietal and white matter regional haemodynamics and cognitive impairments, even in the absence of focal infarction. However, these associations have not been investigated in children with moyamoya. We examined the relationship between regional haemodynamics and ratings of intellectual ability and executive function, using hypercapnic challenge blood oxygen level-dependent magnetic resonance imaging of cerebrovascular reactivity in a consecutive cohort of children with confirmed moyamoya. Thirty children were included in the final analysis (mean age: 12.55 ± 3.03 years, 17 females, 15 idiopathic moyamoya and 15 syndromic moyamoya). Frontal haemodynamics were abnormal in all regardless of stroke history and comorbidity, but occipital lobe haemodynamics were also abnormal in children with syndromic moyamoya. Executive function deficits were noted in both idiopathic and syndromic moyamoya, whereas intellectual ability was impaired in syndromic moyamoya, even in the absence of stroke. Analysis of the relative effect of regional abnormal haemodynamics on cognitive outcomes demonstrated that executive dysfunction was predominantly explained by right parietal and white matter haemodynamics independent of stroke and comorbidity, while posterior circulation haemodynamics predicted intellectual ability. These results suggest that parietal and posterior haemodynamics play a compensatory role in overcoming frontal vulnerability and cognitive impairment.

Longitudinal angiographic characterization of the efficacy of combined cerebral revascularization using minimally invasive encephalodurosynangiosis in patients with moyamoya angiopathy

Moyamoya angiopathy (MMA) can be treated using direct, indirect, or combined revascularization procedures. We perform combined revascularization using the STA-MCA bypass and minimally invasive encephalodurosynangiosis (MIS-EDS). Due to lack of systematic analyses to date it remains unclear whether and to which extent this limited EDS serves as a growth source for extracerebral blood vessels into the brain. The objective of the current study is to characterize the extent of angiographic filling of MIS-EDS and STA-MCA bypass development over time and to determine possible predictors of EDS development in adult MMA patients. Single-center retrospective analysis of 81 MMA patients (139 hemispheres) treated with a MIS-EDS and STA-MCA bypass was performed. Angiographic images and clinical/operative data were reviewed and scored. Uni-/ and multivariate Cox regression analyses identified preoperative predictors of good EDS vascularization. At 3-6 months after surgery EDS showed moderate and high angiographic filling in 40% and 5% of hemispheres, respectively. After 12 months moderate and high filling was found in 57% and 4% of hemispheres, respectively. STA-MCA bypass filling was moderate in 47% and high in 7% of hemispheres at 3-6 months and 45% moderate and 9% high after 12 months. High STA-MCA bypass filling on angiography was a negative predictor of EDS development. MIS-EDS is a simple technique and serves as a source of vessel growth into the brain. EDS development lags behind that of STA-MCA bypass and can be recommended as an additive revascularization source when combined with a direct bypass.

Baseline Hemodynamic Impairment and Revascularization Outcome in Newly Diagnosed Adult Moyamoya Disease Determined by Pseudocontinuous Arterial Spin Labeling

OBJECTIVE

The study aimed to investigate the hemodynamic features and independent predictors of neoangiogenesis after revascularization in moyamoya disease (MMD) by pseudocontinuous arterial spin labeling magnetic resonance imaging (pCASL MRI).

METHODS

Thirty-nine MMD patients were categorized into infarction group, hemorrhagic group, and atypical group. All patients underwent combined bypass surgery and pCASL MRI with postlabeling delays (PLD) of 1525 ms and 2525 ms. Absolute CBF_MCA (cerebral blood flow in middle cerebral artery territory), relative CBF_MCA (CBF_MCA 2525 ms/CBF_MCA 1525 ms), and spatial coefficient of variation of MCA (CoV_MCA) were analyzed. Relationships between CBF_MCA and the following clinical parameters were assessed: Suzuki stage, modified Rankin scale (mRS), cerebrovascular accident lesion score, and deep medullary veins score. Potential predictors for favorable neoangiogenesis and hemodynamic changes were explored as well.

RESULTS

Preoperative CBF_MCA differed among MMD patients with variable clinical presentations, Matsushima stages, modified Rankin Scale scores, CVA scores, and deep medullary vein scores. After bypass surgery, mean CBF_MCA increased significantly in the infarction group (P = 0.027) and decreased in the hemorrhagic group (P = 0.043), while spatial CoV_MCA was observed to decline in all groups. Higher preoperative relative CBF_MCA and spatial CoV_MCA were independent predictors for robust neoangiogenesis after bypass. The cutoff value of 0.330 of spatial CoV_MCA at long PLD yielded the best sensitivity at 82.1% and specificity at 81.8%. Furthermore, both preoperative relative CBF_MCA and spatial CoV_MCA showed mild positive correlations with ΔmRS in MMD patients.

CONCLUSIONS

pCASL-MRI with multiple PLDs could reflect preoperative hemodynamic impairment and predict the neoangiogenesis after combined bypass surgery in moyamoya patients.

Intravenous thrombolysis and endovascular thrombectomy for acute ischaemic stroke in patients with Moyamoya disease - a systematic review and meta-summary of case reports

BACKGROUND AND AIMS

Patients with Moyamoya disease (MMD) can present with ischaemic or haemorrhagic stroke. There is no good evidence for treatment strategies in MMD-associated acute ischaemic stroke (AIS), particularly for treatments like intravenous thrombolysis (IVT) and endovascular thrombectomy (ET). As the intracranial vessels are friable in MMD, and the risk of bleeding is high, the use of IVT and ET is controversial. To clarify the safety and efficacy of IVT/ET in the treatment of MMD-associated AIS, we performed a systematic review and meta-summary to examine this issue.

METHODS

A systematic search was performed from four electronic databases: PubMed (MEDLINE), Cochrane Library, EMBASE and Scopus, profiling data from inception till 21 November 2021, as well as, manually on Google Scholar.

RESULTS

Ten case reports detailing 10 MMD patients presenting with AIS and undergoing IVT or ET, or both, were included in the analysis. The median National Institute of Health Stroke Scale score at presentation was 10 (Interquartile Range [IQR] = 6.0-16.5). IVT alone was instituted in 6 patients, primary ET was attempted in 2, and 2 had received bridging IVT with ET. Of the 4 patients who underwent ET, 2 patients achieved successful reperfusion (modified Thrombolysis In Cerebral Infarction scale [mTICI] ≥ 2b). In terms of functional outcomes, One patient achieved complete recovery (modified Rankin Scale 0), 4 patients attained improvement in neurological status, and 4 had no improvement, whilst functional outcome was unreported in 1 patient. No patient experienced symptomatic intracranial haemorrhage.

CONCLUSIONS

In this systematic review and meta-summary, the utility of IVT and ET in MMD-associated AIS appears feasible in selected cases. Further larger cohort studies are required to evaluate these treatment approaches.

HIGHLIGHTS

· AIS in MMD was typically managed with bypass surgery but not via thrombolysis or thrombectomy. · In this meta-summary, all patients treated with thrombolysis and/or thrombectomy survived and some experienced symptomatic and/or functional improvement. · Further larger cohort studies are necessary for investigating the role of thrombolysis and/or thrombectomy as treatment of AIS in MMD.

Novel Multifaceted Roles for RNF213 Protein

Ring Finger Protein 213 (RNF213), also known as Mysterin, is the major susceptibility factor for Moyamoya Arteriopathy (MA), a progressive cerebrovascular disorder that often leads to brain stroke in adults and children. Although several rare RNF213 polymorphisms have been reported, no major susceptibility variant has been identified to date in Caucasian patients, thus frustrating the attempts to identify putative therapeutic targets for MA treatment. For these reasons, the investigation of novel biochemical functions, substrates and unknown partners of RNF213 will help to unravel the pathogenic mechanisms of MA and will facilitate variant interpretations in a diagnostic context in the future. The aim of the present review is to discuss novel perspectives regarding emerging RNF213 roles in light of recent literature updates and dissect their relevance for understanding MA and for the design of future research studies. Since its identification, RNF213 involvement in angiogenesis and vasculogenesis has strengthened, together with its role in inflammatory signals and proliferation pathways. Most recent studies have been increasingly focused on its relevance in antimicrobial activity and lipid metabolism, highlighting new intriguing perspectives. The last area could suggest the main role of RNF213 in the proteasome pathway, thus reinforcing the hypotheses already previously formulated that depict the protein as an important regulator of the stability of client proteins involved in angiogenesis. We believe that the novel evidence reviewed here may contribute to untangling the complex and still obscure pathogenesis of MA that is reflected in the lack of therapies able to slow down or halt disease progression and severity.

Cerebrofacial vascular metameric syndrome associated with Moyamoya syndrome: a rare case report

INTRODUCTION

Neural crest and mesoderm cell dysfunction of certain metameric level result in vascular malformations, i.e., cerebrofacial arteriovenous metameric syndrome (CAMS) and cerebrofacial venous metameric syndrome (CVMS). Moyamoya disease is a progressive steno-occlusive disease in the terminal portions of the bilateral internal carotid artery. The patient in this case report was a child with cerebrofacial vascular metameric syndrome, associated with moyamoya syndrome.

CASE REPORT

Child, 7 months old, female, admitted to the emergency department with seizures, hemangioma on the right half of the face (forehead, upper eyelid, and upper lip), and left hemiparesis. The magnetic resonance imaging of the skull indicated increased myelination in the right hemisphere (T2) and atrophy compatible with Sturge-Weber syndrome. Cerebral angiography indicated vasculopathy with bilateral moyamoya pattern, associated with other arteriovenous malformations compatible with cerebrofacial vascular metameric syndrome. Moyamoya syndrome was treated with indirect revascularization (pial synangiosis) achieving good outcomes.

DISCUSSION

Vascular malformations can involve the orbits, face, and brain simultaneously. CAMS with forebrain or hindbrain involvement can be classified into subgroups: I, II, and III. On the other hand, venous malformations in Sturge-Weber syndrome or encephalotrigeminal angiomatosis can be considered CVMS. Moyamoya disease is called syndrome when related to another clinical condition, such as the present case, i.e., neurocutaneous Sturge-Weber syndrome. The association of chronic moyamoya vasculopathy with cerebrofacial vascular metameric syndrome is rare. Further studies are required to establish the best treatment approach.

Strategic tunnelling of superficial temporal artery during bypass surgery for moyamoya disease

BACKGROUND

The superficial temporal artery to middle cerebral artery bypass remains the favoured direct technique of cerebral revascularization in moyamoya angiopathy. We describe a novel technique of tunnelling the superficial temporal artery through the temporalis muscle.

METHODS

The temporalis muscle is raised as a flap off the temporal bone. A triangular window is created on the temporalis fascia, and a tunnel is created for the superficial temporal artery to pass through the muscle belly.

CONCLUSION

This innovative technique allows passage of the superficial temporal artery to the brain without kink or compression ensuring good bypass function and improves long-term patency.

Surgical revascularization for moyamoya angiopathy: Clinical and radiological outcomes of direct and indirect bypasses in 86 affected hemispheres

Moyamoya is a progressive cerebral angiopathy that entails a formidable natural history of repeated ischemic or haemorrhagic insults if not intervened. The potential advantages of direct/combined bypass can be harvested only if they are not outweighed by perioperative morbidity. Direct bypasses for the paediatric group have been less utilized because of small vessel calibres and an inherently more robust angioplasticity. This study was undertaken to examine the clinical and perfusion imaging outcomes of operated moyamoya disease or syndrome patients in Hong Kong's Southeast Asian population. Comparison was made between direct/combined and indirect bypass cohorts. Subgroup analysis of the paediatric cohort was conducted to determine outcomes of a direct-bypass-first strategy. From November 2000 to September 2020, 86 hemispheres underwent revascularization at a tertiary neurosurgical unit with a mean clinical follow-up time of 70.0 months. 70.9% of the procedures involved direct bypasses. Direct/combined revascularization demonstrated superiority in restoring adequate cerebrovascular reserve capacity (CVRC) (63.2% vs 27.3%, p = 0.015), and freedom from transient ischemic attacks in the first 5 years post-operation by Kaplan-Meier plot with log-rank test (p = 0.038). Follow-up imaging revealed 96.5% of the bypass grafts remained patent. Direct/combined procedures significantly predicted restoration of adequate CVRC on follow-up perfusions scans by binary logistic regression (OR 4.57, p = 0.009). Compared to the adult cohort, direct bypasses in children carried no excessive perioperative morbidity. These results support a liberal bypass-first paradigm in both adult and paediatric cohorts.

Piriformis syndrome as a result of intramuscular haematoma mimicking cauda equina effectively treated with piriformis tendon release

We present a case of piriformis syndrome in a woman in her 30's following low energy trauma, presenting with unilateral lower limb weakness, altered sensation and urinary retention. CT imaging revealed a bulky piriformis muscle which was further clarified on MRI as an intramuscular haematoma within the left piriformis causing compression of the left lumbosacral plexus. Haematoma formation was exacerbated due to use of an antiplatelet medication the patient was taking for Moyamoya disease, which carries an increased risk of cerebrovascular accident. Surgical exploration of the piriformis and sciatic nerve was undertaken and confirmed a haematoma within the piriformis. A full release of the piriformis tendon was undertaken, and the sciatic nerve was inspected, no further abnormality was found. After review in clinic post-discharge, the patient reported normal sensation and normal muscle power in her feet.