Pediatric Moyamoya disease

Hemorrhagic stroke in children

Hemorrhagic stroke (HS) in childhood accounts for almost 50% of childhood strokes, is among the top ten causes of deaths, or determines lifelong disability. These facts form significant socio-economic and demographic problems. The purpose of this review is to analyze current knowledge about HS in children. The data on HS terminology are presented, taking into account the International Classification of Diseases 11 edition. Attention is paid to the epidemiology of HS in children, including the results of individual local studies. The risk factors of HS in children were studied with an analysis of the causal, pathophysiological mechanisms of HS of various etiologies. The ideas about the clinical manifestations of HS in children are described. The analysis of HS treatment in children was carried out with an emphasis on achievements in neurointensive therapy of the acute period of HS. This review also includes information on the outcomes of HS in children.

An Unusual Presentation of Moyamoya Disease in a Pediatric Patient

Moyamoya disease (MMD) is a chronic cerebro-vasculopathy that is extremely rare in the pediatric population. The main characteristic feature is the progressive stenosis in the internal carotid artery with or without the involvement of its main branches in the circle of Willis leading to ischemic stroke. Patients have clinical manifestations related to cerebral ischemia in the carotid branch territories, such as sensory impairment, hemiparesis, and aphasia/dysarthria. Herein, we report a case of MMD in a six-year-old Emirati female who presented with unusual manifestations of MMD in the form of headache, vomiting, and double vision and was diagnosed with MMD based on a brain MRI with angiography. To our knowledge, this is the first reported case of MMD in the United Arab Emirates.

Can Hemorrhagic Stroke Genetics Help Forensic Diagnosis in Pediatric Age (<5 Years Old)?

When stroke occurs in pediatric age, it might be mistakenly interpreted as non-accidental head injury (NAHI). In these situations, a multidisciplinary approach is fundamental, including a thorough personal and familial history, along with accurate physical examination and additional investigations. Especially when the clinical picture is uncertain, it is important to remember that certain genetic conditions can cause bleeding inside the brain, which may resemble NAHI. Pediatric strokes occurring around the time of birth can also be an initial sign of undiagnosed genetic disorders. Hence, it is crucial to conduct a thorough evaluation, including genetic testing, when there is a suspicion of NAHI but the symptoms are unclear. In these cases, a characteristic set of symptoms is often observed. This study aims to summarize some of the genetic causes of hemorrhagic stroke in the pediatric population, thus mimicking non-accidental head injury, considering elements that can be useful in characterizing pathologies. A systematic review of genetic disorders that may cause ICH in children was carried out according to the Preferred Reporting Item for Systematic Review (PRISMA) standards. We selected 10 articles regarding the main genetic diseases in stroke; we additionally selected 11 papers concerning patients with pediatric stroke and genetic diseases, or studies outlining the characteristics of stroke in these patients. The disorders we identified were Moyamoya disease (MMD), COL4A1, COL4A2 pathogenic variant, Ehlers-Danlos syndrome (E-D), neurofibromatosis type 1 (Nf1), sickle cell disease (SCD), cerebral cavernous malformations (CCM), hereditary hemorrhagic telangiectasia (HHT) and Marfan syndrome. In conclusion, this paper provides a comprehensive overview of the genetic disorders that could be tested in children when there is a suspicion of NAHI but an unclear picture.

Structural equation model based on salutogenesis theory for evaluating factors affecting health-related quality of life in adolescents with moyamoya disease

Moyamoya disease is a cerebrovascular disorder and a significant chronic health concern requiring regular monitoring to control the disease and its related complications. We examined a hypothetical model by integrating the concepts of a structural health-related quality-of-life model based on the salutogenesis theory, and to identify how social support, sense of coherence, and stress contribute to health behaviors, subjective health status, and quality of life in adolescents with moyamoya disease among 239 adolescents in Korea. A structural equation model was used to analyze the data. The fitness of the hypothetical model with the salutogenesis theory was satisfactory, showing that the goodness-of-fit index = 0.91, adjusted goodness-to-fit index = 0.90, comparative fit index = 0.92, normed fit index = 0.91, incremental fit index = 0.91, standardized root mean squared residual = 0.04, root mean square error of approximation = 0.07, parsimony normed fit index = 0.61, parsimony goodness of fit index = 0.51. The model explained 68.9% of quality of life. Health behavior (β = -0.173, p = 0.467) and stress (β = -0.557, p < 0.001) had significant direct and total effects on quality of life. Sense of coherence had a significant direct (β = 0.371, p = 0.003), indirect (β = 0.220, p = 0.013), and total (β = 0.590, p < 0.001) effect on quality of life. This study found that sense of coherence was significant factors contributing to lower stress, improved health status, and quality of life in adolescents with moyamoya disease. To improve the quality of life for adolescents with moyamoya disease, comprehensive nursing interventions need to be developed and applied.

A Novel Method for Improving the Accuracy of MR-derived Patient-specific Vascular Models using X-ray Angiography

MR imaging, a noninvasive radiation-free imaging modality commonly used during clinical follow up, has been widely utilized to reconstruct realistic 3D vascular models for patient-specific analysis. In recent work, we used patient-specific hemodynamic analysis of the circle of Willis to noninvasively assess stroke risk in pediatric Moyamoya disease (MMD)-a progressive steno-occlusive cerebrovascular disorder that leads to recurrent stroke. The objective was to identify vascular regions with critically high wall shear rate (WSR) that signifies elevated stroke risk. However, sources of error such as insufficient resolution of MR images can negatively impact vascular model accuracy, especially in areas of severe pathological narrowing, and thus diminish clinical relevance of simulation results, as local hemodynamics are sensitive to vessel geometry. To improve the accuracy of MR-derived vascular models, we have developed a novel method for adjusting model vessel geometry utilizing 2D X-ray angiography (XA), which is considered the gold standard for clinically assessing vessel caliber. In this workflow, "virtual angiographies" (VAs) of 3D MR-derived vascular models are conducted, producing 2D projections that are compared with corresponding XA images to guide the local adjustment of modeled vessels. This VA-comparison-adjustment loop is iterated until the two agree, as confirmed by an expert neuroradiologist. Using this method, we generated models of the circle of Willis of two patients with a history of unilateral stroke. Blood flow simulations were performed using a Navier-Stokes solver within an isogeometric analysis framework, and WSR distributions were quantified. Results for one patient show as much as 45% underestimation of local WSR in the stenotic left anterior cerebral artery (LACA), and up to a 56% underestimation in the right anterior cerebral artery when using the initial MR-derived model compared to the XA-adjusted model. To evaluate whether XA-based adjustment improves model accuracy, vessel cross-sectional areas of the pre- and post-adjustment models were compared to those seen in 3D CTA images of the same patient. CTA has superior resolution and signal-to-noise ratio compared to MR imaging but is not commonly used in the clinic due to radiation exposure concerns, especially in pediatric patients. While the vessels in the initial model had normalized root mean squared deviations (NRMSDs) ranging from 26% to 182% and 31% to 69% in two patients with respect to CTA, the adjusted vessel NRMSDs were comparatively smaller (32% to 53% and 11% to 42%). In the mildly stenotic LACA of patient 1, the NRMSDs for the pre- and post-adjusted models were 49% and 32%, respectively. These findings suggest that our XA-based adjustment method can considerably improve the accuracy of vascular models, and thus, stroke-risk prediction. An accurate, individualized assessment of stroke risk would be of substantial help in guiding the timing of preventive surgical interventions in pediatric MMD patients.

The Genetic Basis of Strokes in Pediatric Populations and Insight into New Therapeutic Options

Strokes within pediatric populations are considered to be the 10th leading cause of death in the United States of America, with over half of such events occurring in children younger than one year of life. The multifactorial etiopathology that has an influence on stroke development and occurrence signify the importance of the timely recognition of both modifiable and non-modifiable factors for adequate diagnostic and treatment approaches. The early recognition of a stroke and stroke risk in children has the potential to advance the application of neuroprotective, thrombolytic, and antithrombotic interventions and rehabilitation strategies to the earliest possible timepoints after the onset of a stroke, improving the outcomes and quality of life for affected children and their families. The recent development of molecular genetic methods has greatly facilitated the analysis and diagnosis of single-gene disorders. In this review, the most significant single gene disorders associated with pediatric stroke are presented, along with specific therapeutic options whenever they exist. Besides monogenic disorders that may present with stroke as a first symptom, genetic polymorphisms may contribute to the risk of pediatric and perinatal stroke. The most frequently studied genetic risk factors are several common polymorphisms in genes associated with thrombophilia; these genes code for proteins that are part of the coagulation cascade, fibrolysis, homocystein metabolism, lipid metabolism, or platelets. Single polymorphism frequencies may not be sufficient to completely explain the stroke causality and an analysis of several genotype combinations is a more promising approach. The recent steps forward in our understanding of the disorders underlying strokes has given us a next generation of therapeutics and therapeutic targets by which to improve stroke survival, protect or rebuild neuronal connections in the brain, and enhance neural function. Advances in DNA sequencing and the development of new tools to correct human gene mutations have brought genetic analysis and gene therapy into the focus of investigations for new therapeutic options for stroke patients.

Image-based patient-specific flow simulations are consistent with stroke in pediatric cerebrovascular disease

Moyamoya disease (MMD) is characterized by narrowing of the distal internal carotid artery and the circle of Willis (CoW) and leads to recurring ischemic and hemorrhagic stroke. A retrospective review of data from 50 pediatric MMD patients revealed that among the 24 who had a unilateral stroke and were surgically treated, 11 (45.8%) had a subsequent, contralateral stroke. There is no reliable way to predict these events. After a pilot study in Acta-/- mice that have features of MMD, we hypothesized that local hemodynamics are predictive of contralateral strokes and sought to develop a patient-specific analysis framework to noninvasively assess this stroke risk. A pediatric MMD patient with an occlusion in the right middle cerebral artery and a right-sided stroke, who was surgically treated and then had a contralateral stroke, was selected for analysis. By using an unsteady Navier-Stokes solver within an isogeometric analysis framework, blood flow was simulated in the CoW model reconstructed from the patient's postoperative imaging data, and the results were compared with those from an age- and sex-matched control subject. A wall shear rate (WSR) > 60,000 s-1 (about 12 × higher than the coagulation threshold of 5000 s-1 and 9 × higher than control) was measured in the terminal left supraclinoid artery; its location coincided with that of the subsequent postsurgical left-sided stroke. A parametric study of disease progression revealed a strong correlation between the degree of vascular morphology altered by MMD and local hemodynamic environment. The results suggest that an occlusion in the CoW could lead to excessive contralateral WSRs, resulting in thromboembolic ischemic events, and that WSR could be a predictor of future stroke.

A case report of moyamoya disease in children treated with encephalo-duro-myo-arterio-pericranial synangiosis

Moyamoya disease that manifests during childhood may pose a special challenge for surgeons. We report a case of a 10-year-old girl who suffered from moyamoya disease and was successfully treated with encephalo-duro-myo-arterio-pericranial synangiosis (EDMAPS). She presented with a recurrent transient ischemic attack that worsened for 1 year. She was aphasic globally (sensory and motor) and had slightly weak right extremities. Her magnetic resonance angiography and computed tomography angiography showed the typical features of moyamoya disease with bilateral stenosis at the terminal internal carotid artery, bilaterally abnormal vascular networks, and a left ischemic event involving the temporoparietal region. She was recovered well after underwent bilateral EDMAPS, fully regained her language function after 3 months, and gathered her strength back. Therefore, EDMAPS could be a good, safe, and effective treatment for moyamoya disease in children.

Safety and efficacy of remote ischemic conditioning in pediatric moyamoya disease patients treated with revascularization therapy

BACKGROUND

Revascularization surgery has been the standard treatment to prevent ischemic stroke in pediatric Moyamoya disease (MMD) patients with ischemic symptoms. However, perioperative complications, such as hyperperfusion syndrome, new infarct on imaging, or ischemic stroke, are inevitable. Remote ischemic conditioning (RIC) is a noninvasive and easy-to-use neuroprotective strategy, and it has potential effects on preventing hyperperfusion syndrome and ischemic infarction.

AIMS

The aim of this study is to investigate the safety and efficacy of RIC in pediatric MMD patients undergoing revascularization surgery.

METHOD

A total of 60 pediatric MMD patients with one or more ischemic symptoms will be recruited and allocated in 1:1 ratio to the RIC group and sham group, respectively. Both RIC and sham RIC will be performed twice daily for 7 consecutive days before revascularization surgery with different cuff pressures during the ischemia period (50 mmHg over-systolic blood pressure and 30 mmHg). Single photon emission computed tomography will be performed within 7 days preoperatively and 3 months postoperatively, respectively, to evaluate the cerebral perfusion status. Other outcomes, including safety, plasma biomarker, functional outcome, and the incidence of infarction and its size, will also be evaluated.

CONCLUSION

This study will provide insights into the preliminary proof of principle, safety, and efficacy of RIC in pediatric MMD patients undergoing revascularization surgery therapy, and this data will provide parameters for future larger scale clinical trials if efficacious.