Surgical revascularisation for childhood moyamoya

Pediatric Moyamoya Revascularization Perioperative Care: A Modified Delphi Study

BACKGROUND

Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities.

METHODS

Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement.

RESULTS

Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery.

CONCLUSIONS

In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.

Magnetic Resonance Imaging/Angiography Versus Catheter Angiography for Annual Follow-up of Pediatric Moyamoya Patients: A Cost Outcomes Analysis

BACKGROUND

Digital subtraction angiography (DSA) assesses revascularization in pediatric moyamoya patients after surgery, but MRI and angiography (MRI/A) may provide comparable data.

OBJECTIVE

To evaluate DSA and MRI/A with respect to clinical utility in postoperative follow-up, complication profile, and relative cost at 1 year.

METHODS

All pediatric moyamoya patients who received bilateral indirect revascularization between 2011 and 2020 were retrospectively reviewed at 1 institution. Patients who underwent MRI/A-only, DSA-only, or both after 1 year were compared.

RESULTS

Eighty-two patients were included. At 1 year, patients who underwent either MRI/A (n = 29) or DSA (n = 40) had no significant differences in detection rate of new at-risk hypovascular territories (6.9% vs 2.5%, P = .568) or need for subsequent revascularization beyond the mean 40 ± 24-month follow-up period (3.4% vs 5.0%, P > .9). Among patients who underwent both MRI/A and DSA (n = 13), both studies identified the same at-risk territories. No patients experienced MRI/A-related complications, compared with 3 minor DSA-related complications. The use of MRI/A yielded a 6.5-fold reduction in cost per study vs DSA at 1 year.

CONCLUSION

Using DSA to follow moyamoya patients after indirect revascularization is generally safe but associated with a low rate of minor complications and a 6.5-fold greater financial cost relative to MRI/A. These data support changing practice to eliminate the use of DSA when following routine bilateral moyamoya cases in the absence of clinical symptoms or specific concerns. Using MRI/A as the primary postoperative follow-up modality in this select population provides noninferior care and greater patient access, while reducing cost and potentially decreasing risk.

Surgical revascularizations for pediatric moyamoya: a systematic review, meta-analysis, and meta-regression analysis

INTRODUCTION

There is no clear consensus regarding the technique of surgical revascularization for moyamoya disease and syndrome (MMD/MMS) in the pediatric population. Previous meta-analyses have attempted to address this gap in literature but with methodological limitations that affect the reliability of their pooled estimates. This meta-analysis aimed to report an accurate and transparent comparison between studies of indirect (IB), direct (DB), and combined bypasses (CB) in pediatric patients with MMD/MMS.

METHODS

In accordance with PRISMA guidelines, systematic searches of Medline, Embase, and Cochrane Central were undertaken from database inception to 7 October 2022. Perioperative adverse events were the primary outcome measure. Secondary outcomes were rates of long-term revascularization, stroke recurrence, morbidity, and mortality.

RESULTS

Thirty-seven studies reporting 2460 patients and 4432 hemispheres were included in the meta-analysis. The overall pooled mean age was 8.6 years (95% CI: 7.7; 9.5), and 45.0% were male. Pooled proportions of perioperative adverse events were similar between the DB/CB and IB groups except for wound complication which was higher in the former group (RR = 2.54 (95% CI: 1.82; 3.55)). Proportions of post-surgical Matsushima Grade A/B revascularization favored DB/CB over IB (RR = 1.12 (95% CI 1.02; 1.24)). There was no significant difference in stroke recurrence, morbidity, and mortality. After meta-regression analysis, year of publication and age were significant predictors of outcomes.

CONCLUSIONS

IB, DB/CB are relatively effective and safe revascularization options for pediatric MMD/MMS. Low-quality GRADE evidence suggests that DB/CB was associated with better long-term angiographic revascularization outcomes when compared with IB, although this did not translate to long-term stroke and mortality benefits.

A Retrospective Study on Clinical Features of Childhood Moyamoya Disease

BACKGROUND

Childhood moyamoya disease (MMD) can lead to progressive and irreversible neurological impairment. Early age at onset is likely associated with a worst prognosis of the disease. The study aims to summarize the clinical characteristics of childhood MMD for supporting the diagnosis and treatment of early MMD.

METHODS

A retrospective study was conducted on children aged zero to 16 years who were diagnosed with MMD in the Department of Neurology and neurosurgery of our hospital from October 2016 to April 2020. The clinical characteristics of children with MMD were summarized for analysis, and the distribution of sex and initial attack type among different age groups was determined by data comparison.

RESULTS

The study surveyed 114 children (male to female sex ratio of 1:1.07) with MMD, and 6.1% of them had family history. The mean age of onset was 7.15 ± 3.30 years, and the peak age of onset was five to eight years. The most common initial attack type was transient ischemic attack (TIA) (62 cases, 54.4%) with limb weakness. The incidence of the initial attack type in the three age groups was varied (P < 0.05). The result of overall prognosis was good in 86 cases (89.6%).

CONCLUSIONS

In this study, MMD cases were mainly ischemic type and TIA was the most common initial attack type. Infant group was more prone to have cerebral infarction, whereas preschool and school-age groups tended to have TIA. The treatments and prognosis of the studied MMD cases were achieved with good outcomes.

Management of Pediatric Stroke - Challenges and Perspectives from Resource-limited Settings

Childhood stroke is not as common as adult stroke, but it is underrecognized the world over. Diagnosis is often delayed due to lack of awareness not only by the lay public but also by emergency and front-line health care workers. Despite the relative rarity of childhood stroke, the impact on morbidity, mortality and the economic burden for families and society is high, especially in poorly resourced settings. The risk factors for stroke in children differ from the adult population where lifestyle factors play a more important role. The developmental aspects of the pediatric cerebral vasculature and hematological maturational biology affects the clinical presentation, investigation, management and outcomes of childhood stroke in a different way compared to adults. The management of childhood stroke is currently based on expert guidelines and evidence extrapolated from adult studies. Hyperacute therapies that have revolutionized the treatment of stroke in adults cannot be easily applied to children at this stage due to the diagnostic delays, diverse risk factors and developmental considerations mentioned above. Much has been achieved in the understanding of genetic, acquired, preventable and recurrent stroke risk factors in the past decade through international collaborative efforts like the International Pediatric Stroke Study. Evidence for the prevention and treatment of childhood stroke remains elusive. Even more elusive are relevant and achievable management guidelines for pediatric stroke in resource-limited settings. This narrative review focusses on the current management practices globally, emphasizing the challenges, and gaps in knowledge of pediatric stroke in low- and middle-income countries and other areas with limited resources. Priorities and some potential solutions at national and local level are suggested for these settings.

Wide Arterial Sparing Encephalo-Duro-Synangiosis for Moyamoya: Surgical Technique and Outcomes

BACKGROUND

Moyamoya is managed by surgical revascularization, but no standardized method has yet been universally adopted.

OBJECTIVE

To describe a new indirect bypass technique for pediatric moyamoya, wide arterial sparing encephalo-duro-synangiosis (WASEDS), which provides a much wider area of revascularization with minimal compromise to the middle meningeal arterial tree compared with traditional procedures. Initially used as a salvage technique after failed encephalo-duro-arterio-synangiosis, its success later motivated its use as a first-line procedure.

METHODS

Clinical and radiographic records of patients who underwent WASEDS for moyamoya from 2009 to 2020 were reviewed. Brain perfusion relative cerebral blood volume on the side of the WASEDS procedure was calculated. Two-tailed paired t tests were performed to identify the statistically significant differences ( P ≤ .05).

RESULTS

WASEDS was successfully performed on 8 patients for a total of 14 cerebral hemispheres. Age ranged from 2 to 25 years. There were no mortalities. The average clinical and radiographic follow-up was 49.79 months (range 2-126 months), demonstrating improvement in neurological condition and no postoperative stroke and significant diminution or cessation of transient ischemic attacks in all patients. Relative cerebral blood volume increased 9.24% after the WASEDS procedure ( P = .012). There were no neurological complications. There were 2 pseudomeningoceles related to the extensive dural openings.

CONCLUSION

WASEDS is a safe and effective indirect revascularization technique for both primary and salvage techniques. It provides an extensive area of cortical revascularization with no compromise of the middle meningeal vasculature and subjective reports of early improvement in cognition and behavior. The main disadvantage is elevated risk of pseudomeningocele secondary to the large craniotomy.

Surgical revascularization for pediatric moyamoya: the role of surgical mentorship in sustaining and developing a neurovascular service

OBJECTIVE

Obtaining operative experience for the treatment of rare conditions in children represents a challenge for pediatric neurosurgeons. Starting in November 2017, a surgeon was mentored in surgical revascularization (SR) for pediatric moyamoya with a view to service development and sustainability. The aim of this audit was to evaluate early outcomes of SR for pediatric moyamoya during and following a surgical mentorship.

METHODS

A retrospective cohort study with chart/database review of consecutive moyamoya surgeries performed by a new attending surgeon (between November 2017 and March 2020) was compared to a previously published cohort from the authors' institution in terms of clinical and angiographic outcomes, complications, operating time, and length of stay. A standardized technique of encephaloduroarteriomyosynangiosis with the superficial temporal artery was used.

RESULTS

Twenty-two children underwent 36 indirect SRs during the study period. Patient demographics were similar between cohorts. The first group of 6 patients had 11 SRs performed jointly by the new attending surgeon mentored by an established senior surgeon (group A), followed by 10 patients with 16 SRs performed independently by the new attending surgeon (group B). The last 6 patients had 9 SRs with the new attending surgeon mentoring a senior fellow (group C) in performing SR. Good angiographic collateralization (Matsushima grades A and B) was observed in 80% of patients, with similar proportions across all 3 groups. A total of 18/19 symptomatic patients (95%) derived symptomatic benefit. There was no perioperative death and, compared to the historical cohort, a similar proportion had a recurrent arterial ischemic event (i.e., acute ischemic stroke) necessitating a second SR (1/22 vs 3/73). Operative times were longest in group C, with no difference in length of hospital stay among the 3 groups.

CONCLUSIONS

Early outcomes demonstrate the feasibility of mentorship for safely incorporating new neurosurgeons in sustaining and developing a tertiary-level surgical service.

Moyamoya syndrome in a young person with Down syndrome: diagnostic and therapeutic considerations

An 18-year-old woman with a history of Down syndrome (DS) presented with left upper extremity weakness. Neurological examination revealed moderate hypotonia throughout, with mild spasticity of the left ankle. She had 2/5 left upper and lower extremity strength, mild pronation with drift in the left arm and 3+ deep tendon reflexes in the left biceps, brachioradialis, patellar and Achilles. Strength was 5/5 in the right upper and lower extremities. A CT angiography of the head and neck with contrast demonstrated severe narrowing of the bilateral supraclinoid internal carotid arteries (ICAs), suggestive of moyamoya pattern. A diagnostic angiography confirmed stenosis in the right and left supraclinoid ICAs. The patient was started on aspirin therapy and underwent an indirect bypass procedure via encephaloduroarteriosynangiosis 6 weeks after initial presentation. DS is associated with a high risk of congenital heart disease, which in turn increases risk of stroke, namely cardioembolic events, including moyamoya disease. Intellectual disability is nearly ubiquitous in DS, thus adding to the challenges of making a diagnosis of moyamoya in this population.

American Society of Hematology 2020 guidelines for sickle cell disease: prevention, diagnosis, and treatment of cerebrovascular disease in children and adults

BACKGROUND

Central nervous system (CNS) complications are among the most common, devastating sequelae of sickle cell disease (SCD) occurring throughout the lifespan.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology are intended to support the SCD community in decisions about prevention, diagnosis, and treatment of the most common neurological morbidities in SCD.

METHODS

The Mayo Evidence-Based Practice Research Program supported the guideline development process, including updating or performing systematic evidence reviews. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations.

RESULTS

The panel placed a higher value on maintaining cognitive function than on being alive with significantly less than baseline cognitive function. The panel developed 19 recommendations with evidence-based strategies to prevent, diagnose, and treat CNS complications of SCD in low-middle- and high-income settings.

CONCLUSIONS

Three of 19 recommendations immediately impact clinical care. These recommendations include: use of transcranial Doppler ultrasound screening and hydroxyurea for primary stroke prevention in children with hemoglobin SS (HbSS) and hemoglobin Sβ0 (HbSβ0) thalassemia living in low-middle-income settings; surveillance for developmental delay, cognitive impairments, and neurodevelopmental disorders in children; and use of magnetic resonance imaging of the brain without sedation to detect silent cerebral infarcts at least once in early-school-age children and once in adults with HbSS or HbSβ0 thalassemia. Individuals with SCD, their family members, and clinicians should become aware of and implement these recommendations to reduce the burden of CNS complications in children and adults with SCD.

Cerebral Revascularization for Moyamoya Syndrome Associated with Sickle Cell Disease: A Systematic Review of the Literature on the Role of Extracranial-Intracranial Bypass in Treating Neurologic Manifestations of Pediatric Patients with Sickle Cell Disease

Moyamoya syndrome (MMS) in patients with sickle cell disease (SCD) accentuates the risk of recurrent strokes. Chronic transfusion therapy (CTT) is an excellent option for preventing recurrent strokes in most patients with SCD. In SCD with MMS, CTT may fail as a long-term solution. Cerebral revascularization, in the form of extracranial-intracranial bypass, has been shown to prevent recurrent strokes in this cohort. We review the evolution of this paradigm shift in the management of SCD-associated MMS. A systematic review, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol, was conducted. Our primary objectives were 1) to study the evolution of cerebral revascularization techniques in management of MMS in SCD and 2) to analyze the impact of neurosurgical intervention in this high-risk population. Four patients with SCD-associated MMS, who underwent indirect cerebral revascularization at our institute were retrospectively reviewed. A summary of 13 articles chronicling the advent and subsequent evolution of cerebral revascularization as a viable treatment strategy for stroke prevention in SCD-associated MMS is presented. The literature review suggests that early detection and surgical intervention (in addition to CTT) could significantly reduce stroke recurrence and improve neurocognitive outcome. Our short series of 4 patients also had a good outcome and no recurrence of strokes postoperatively. The literature emphasizes the use of a traditional standardized protocol for early identification (transcranial Dopplers, selective magnetic resonance angiography, and CTT). Early treatment and screening that involves early magnetic resonance angiography and referral to neurosurgery for revascularization may be considered for this high-risk population.

Surgical outcomes for pediatric moyamoya: a systematic review and meta-analysis

OBJECTIVE

The optimal revascularization for pediatric moyamoya for reducing the incidence of future stroke events remains to be determined.

METHODS

The authors conducted a search of PubMed, MEDLINE, Embase, and Web of Science electronic databases from inception until January 2019. The primary endpoint was the presence of a future ischemic stroke event. Secondary endpoints were angiographic outcomes as measured by postoperative Matsushima grade and clinical symptom persistence. Patients who underwent either direct or combined direct/indirect revascularization were classified into the direct cohort. Data from each study on presence of postoperative stroke events were used to generate standardized mean differences and 95% confidence intervals, which were combined using inverse variance-weighted averages of standardized mean differences in a random effects model.

RESULTS

Twenty-nine studies met the inclusion criteria for analysis, comprising 2258 patients (1011 males, mean age 8.3 ± 1.8 years) who were followed up clinically for an average of 71.4 ± 51.3 months. One hundred fifty-four patients underwent direct bypass alone, 680 patients underwent either direct or combined direct/indirect revascularization procedures, while 1424 patients underwent indirect bypass alone. The frequencies of future stroke events in patients undergoing direct bypass alone, combined bypass, or indirect bypass alone were 1 per 190.3 patient-years, 1 per 108.9 patient-years, and 1 per 61.1 patient-years, respectively, in each cohort. The estimated stroke rates were 9.0% with indirect revascularization, 4.5% with direct revascularization alone, and 6.0% with combined revascularization. A forest plot did not reveal any significant differences in the incidence of future stroke events or angiographic outcomes following direct-only, combined, or indirect-only revascularization.

CONCLUSIONS

Direct, indirect, and combined indirect/direct bypass techniques are all effective revascularization options for pediatric moyamoya disease. A relative paucity of granular studies-and inherent surgical selection bias-limits direct comparison between interventions. Suitably designed prospective cohort studies may be useful in identifying patients likely to receive benefit from specific procedures.

Comparison of Long-Term Effect Between Direct and Indirect Bypass for Pediatric Ischemic-Type Moyamoya Disease: A Propensity Score-Matched Study

Objectives: This study aimed to compare the postoperative risks and long-term effects between direct bypass surgery (DB) and indirect bypass (IB) surgery for pediatric patients with ischemic-type moyamoya disease (MMD). Method: Pediatric patients (under or equal to 18 years old) who were diagnosed as MMD and given surgical treatments at our center between 2009 and 2015 were retrospectively reviewed from a prospective database. Pediatric hemorrhagic-type MMD patients and those who did not undergo digital subtraction angiography (DSA) were excluded. Patients who underwent DB were matched with patients who underwent IB using 1:1 propensity score matching. Postoperative complications, recurrent ischemic stroke events and modified Rankin Scale (mRS) scores at the last follow-up were compared between the matched pairs. Results: A total of 223 pediatric patients were screened, and 138 patients (DB:34, IB:104) were considered for the propensity score match. Thirty four pairs were obtained. Nine patients had postoperative complications, including 6 (17.6%) in the DB group and 3 (8.8%) in the IB group (P = 0.476). The mean follow-up period was 71.9 ± 22.2 months for the DB group and 60.2 ± 24.3 months for the IB group (P = 0.041). Kaplan-Meier analysis showed a longer stroke-free time in the DB group than in the IB group (P = 0.025). At last follow-up, good neurological status (mRS ≤ 1) was achieved in 32 (94.1%) of the DB group and 34 (100.0%) of the IB group. MRS score at last follow-up were significantly lower than at time of admission (all pts: 1.09 ± 0.45 vs. 0.28 ± 0.51, P < 0.001; DB group: 1.12 ± 0.48 vs. 0.32 ± 0.59, P < 0.001; IB group: 1.06 ± 0.42 vs. 0.24 ± 0.43, P < 0.001). Conclusion: Both techniques were effective in improving the neurological status of pediatric ischemic-type MMD patients, and direct bypass surgery might be more superior in preventing recurrent ischemic strokes in the short-term.

Clinical Features, Surgical Treatment, and Long-Term Outcome of a Multicenter Cohort of Pediatric Moyamoya

Objective: This study aims to investigate the clinical features, long-term outcomes, and prognostic predictors of a multicenter cohort of children with moyamoya disease.

Methods: A series of 303 consecutive pediatric moyamoya disease (MMD) patients were screened in the present study. The clinical characteristics were retrospectively collected, and long-term outcomes was evaluated. Furthermore, logistic regression analyses were performed to determine the prognostic predictors for the clinical outcome.

Results: The mean onset age at diagnosis was 9.4 years old. The gender ratio (girl-to-boy ratio) was 1.1:1.0. Among these 303 patients, 13 patients underwent different surgical modalities in bilateral hemispheres, while eight patients failed to follow-up, and were excluded. Therefore, a total of 282 patients were analyzed. Among these patients, 17 patients underwent combined bypass (CB), 47 patients underwent direct bypass (DB), 150 patients underwent indirect bypass (IB), and 68 patients underwent conservative treatment. Furthermore, recurrent stroke events were observed in 35 patients (12.4%). The Kaplan-Meier analysis demonstrated that there was no significant difference in either ischemia or hemorrhage-free time among the different surgical modalities (P = 0.67 and 0.79, respectively). Furthermore, longer ischemia-free time was observed in the surgical group, when compared to the conservative group (P < 0.01). In addition, 82.7% (177/214) of patients who underwent surgical treatment obtained good outcomes (mRS 0-1), which were significantly higher than the rate of patients who underwent conservative treatment (52.9%, 36/68; P < 0.01). The rate of patients with improved symptoms was also significantly different (93.0 vs. 16.2%, P < 0.01). However, no significant difference was observed in the rate of good outcomes, disability, and improved symptoms among the different surgical modalities. The logistic regression analyses revealed that postoperative ischemic events were the only risk factor associated with unfavorable clinical outcome (OR:3.463; 95% CI:1.436–8.351; P < 0.01).

Conclusion: CB, DB, and IB might have similar effects on long-term clinical outcome in pediatric MMD. However, surgical revascularization is superior, when compared to conservative treatment. Furthermore, postoperative ischemic events were confirmed as potential prognostic factors associated with unfavorable clinical outcome.

Moyamoya Vasculopathy in Indian Children: Our Experience

Background:

Moyamoya vasculopathy is a chronic progressive vaso-occlusive disease affecting the distal intracranial carotid arteries and their proximal branches. It is an important cause of recurrent strokes in children. Surgical revascularization procedures are now considered as the treatment option for moyamoya vasculopathy. The data from Indian children with moyamoya vasculopathy are limited to a very few studies.

Study Design:

We analyzed the records of children with moyamoya vasculopathy treated at our tertiary care center from 2000 to 2014. Our study population included all patients (aged 0–18 years) with moyamoya disease/syndrome (MMD/MMS). The demographic data, clinical characteristics, imaging, treatment details, and surgical procedures performed were reviewed.

Results:

A total of 41 patients (females-19, males-22) were identified. Thirty-three (80.48%) had MMD and eight (19.5%) had MMS. The mean age (±standard deviation) at presentation was 6.26 ± 3.79 years (range: 6 months–14 years). Majority had ischemic events at onset; none had hemorrhagic manifestations. Twenty-eight (68.29%) patients underwent surgery (a total of 33 surgical procedures, bilateral in five and unilateral in 23) and 13 (31.7%) were managed conservatively. The median duration of follow-up was 2.2 ± 1.85 years (range: 4 months–7 years). Two/thirteen patients (15%), who were managed conservatively, had recurrent strokes as against none (0/28) in the operated patients. No mortality was observed in our cohort.

Conclusion:

We agree with previous studies that Indian patients with moyamoya vasculopathy differ from their Asian and European counterparts. The availability of expertise in revascularization surgeries in various centers should prompt surgery as an efficient and safe treatment option.

[Stroke in children and adolescents]

The occurrence of a stroke in children and adolescents constitutes a rare, critical event that is associated with substantial morbidity and mortality. In addition to the individual suffering for the young patient and the medical burden for the affected family, a stroke is also associated with high follow-up costs for the health system because of the necessary long-term rehabilitative treatment. Establishing an early and prompt diagnosis is of great therapeutic importance. Because of the rarity of the illness and the plethora of clinical manifestations, diagnosis is often delayed. The most frequent clinical presentation is an acute focal-neurological deficit, usually in the form of hemiparesis, but headache, seizures or alteration of consciousness may also be seen. Nowadays, the prompt performance of diffusion-weighted, blood-sensitive magnetic resonance imaging (MRI) constitutes the gold standard. The most relevant risk factors for the occurrence of a stroke in this age cohort are vasculopathies, infections, pathological cardiac conditions or coagulopathies. Recurrence of stroke is dependent on the underlying risk factors. In a substantial percentage of patients, residual neurological deficits are seen.Owing to a lack of randomized controlled trials in children and adolescents with stroke, the optimal treatment approach is still under debate. In addition to anti-platelet medication and heparinization, systematic intravenous thrombolysis and endovascular thrombectomy are other potentially effective treatment options. The long-term prognosis in children is dependent on establishing a correct, early diagnosis.

Clinical features, course, and outcomes of a UK cohort of pediatric moyamoya

Objective

To describe characteristics and course of a large UK cohort of children with moyamoya from multiple centers and examine prognostic predictors.

Methods

Retrospective review of case notes/radiology, with use of logistic regression to explore predictors of outcome.

Results

Eighty-eight children (median presentation age 5.1 years) were included. Thirty-six presented with arterial ischemic stroke (AIS) and 29 with TIA. Eighty had bilateral and 8 unilateral carotid circulation disease; 29 patients had posterior circulation involvement. Acute infarction was present in 36/176 hemispheres and chronic infarction in 86/176 hemispheres at the index presentation. Sixty-two of 82 with symptomatic presentation had at least one clinical recurrence. Fifty-five patients were treated surgically, with 37 experiencing fewer recurrences after surgery. Outcome was categorized as good using the Recovery and Recurrence Questionnaire in 39/85 patients. On multivariable analysis, presentation with TIA (odds ratio [OR] 0.09, 95% confidence interval [CI] 0.02–0.35), headache (OR 0.10, 95% CI 0.02–0.58), or no symptoms (OR 0.08, 95% CI 0.01–0.68) was less likely to predict poor outcome than AIS presentation. Posterior circulation involvement predicted poor outcome (OR 4.22, 95% CI 1.23–15.53). Surgical revascularization was not a significant predictor of outcome.

Conclusions

Moyamoya is associated with multiple recurrences, progressive arteriopathy, and poor outcome in half of patients, especially with AIS presentation and posterior circulation involvement. Recurrent AIS is rare after surgery. Surgery was not a determinant of overall outcome, likely reflecting surgical case selection and presentation clinical status.

Long-term Outcome After Multiple Burr Hole Surgery in Children With Moyamoya Angiopathy: A Single-Center Experience in 108 Hemispheres

BACKGROUND

Multiple burr hole (MBH) surgery is a simple, safe, and effective indirect technique of revascularization in moyamoya angiopathy (MM). However, it is not yet recognized as a first-line treatment.

OBJECTIVE

To assess the long-term outcome and perioperative complications in a large single-center cohort of children with MM who underwent burr hole surgery.

METHODS

This study is a retrospective analysis of children who underwent surgery for MM in a national reference center for pediatric stroke between 1999 and 2015. Sixty-four children (108 hemispheres, median age 7 years) were consecutively treated. The indication for revascularization was previous stroke or transient ischemic attack (TIA) or rapidly progressive disease on brain magnetic resonance imaging (MRI) and digital subtraction angiography. Children were followed with clinical examinations, telephone interviews, and MRI with any clinical recurrence of stroke or TIA used as the primary endpoint. Surgical mortality and morbidity were documented.

RESULTS

Sixty-four patients were operated (bilateral MBH n = 39, unilateral procedure n = 25). At a mean follow-up of 4.2 years and 270.6 patient years, 89.1% of patients had not suffered any recurrent stroke or TIA. A second surgery was required in 5 cases after unilateral revascularization, and in 3 cases after bilateral MBH. Mortality associated with the procedure was 0. Postoperative Matsushima angiographic grading was the only predictive factor of ischemic recurrence ( P = .036).

CONCLUSION

In pediatric MM, MBH compares favorably to other indirect or direct revascularization techniques in children in the prevention of stroke or TIA.

Lacunar infarction in adult patients with moyamoya disease

OBJECTIVES

Lacunar infarctions in moyamoya disease have rarely been described. We aimed to evaluate the features and prognosis of adult moyamoya patients with lacunar infarction.

PATIENTS AND METHODS

We reviewed 696 consecutive moyamoya patients admitted to our hospital from 2009 to 2015 to identify patients with lacunar infarctions. We compared the clinical features and prognosis of adult moyamoya patients with lacunar infarction and those with non-lacunar infarction. Follow-up was conducted by face-to-face reviews or by a structured telephone interview. Outcome measures were recurrent stroke events and functional outcomes by modified Rankin Scale (mRS).

RESULTS

We identified 32 patients with lacunar infarction among 197 adult moyamoya disease patients with infarctions. Patients with lacunar infarctions demonstrated similar angiographic features with patients with non-lacunar infarctions. During a mean follow-up of 33.02±20.49months, we observed recurrent stroke events in 1 patients with lacunar infarction and 14 patients with non-lacunar infarction. The mean follow-up mRS was significantly better in the lacunar group than in the non-lacunar group (0.59±0.56 vs. 1.13±1.24; P<0.001).

CONCLUSION

We identified that the moyamoya patients with lacunar infarctions had better functional outcomes comparing with patients with non-lacunar infarction after revascularization.

Cerebrovascular Reactivity and Intellectual Outcome in Childhood Stroke With Transient Cerebral Arteriopathy

BACKGROUND

Hypercapnic-challenge blood oxygen level-dependent magnetic resonance imaging cerebrovascular reactivity (CVR), measures the regional perfusion response to altered carbon dioxide. CVR correlates with the tissue-level microvascular dysfunction and ischemic risk. Among children with arterial ischemic stroke, transient cerebral arteriopathy (TCA) is a frequent, nonprogressive unilateral intracranial arteriopathy, which typically results in basal ganglia infarction and chronic cerebral artery stenosis. Therefore TCA provides a model for studying the consequences of chronic nonprogressive stenosis using CVR and intellectual outcome. We hypothesized that children with TCA and chronic nonprogressive intracranial artery stenosis have impaired CVR distal to the stenosis and associated cognitive impairment.

METHODS

We studied children with a prior diagnosis of TCA as defined by infarction limited to the basal ganglia, internal capsule, or both; and significant (greater than 50% diameter) residual stenosis of the supraclinoid internal carotid artery, its proximal branches or both. All children had CVR, intellectual function, and infarct volumes quantified.

RESULTS

We performed CVR studies in five children at mean 8.96 years (3.33 to 14.58 years) poststroke. Impaired CVR was limited to the infarct zone and adjacent white matter in most children. Intellectual function was broadly average in all but one subject.

CONCLUSIONS

In children with typical TCA, ipsilateral cortical CVR and intellectual function seem to be preserved despite persistent arterial stenosis in the majority. These findings suggest that chronic revascularization strategies in these children may not be indicated and require further exploration in a larger cohort of children.

Progress on Complications of Direct Bypass for Moyamoya Disease

Moyamoya disease (MMD) involves progressive occlusion of the intracranial internal carotid artery resulting in formation of moyamoya-like vessels at the base of the brain. It can be characterized by hemorrhage or ischemia. Direct vascular bypass is the main and most effective treatment of MMD. However, patients with MMD differ from those with normal cerebral vessels. MMD patients have unstable intracranial artery hemodynamics and a poor blood flow reserve; therefore, during the direct bypass of superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis, perioperative risk factors and anesthesia can affect the hemodynamics of these patients. When brain tissue cannot tolerate a high blood flow rate, it becomes prone to hyperperfusion syndrome, which leads to neurological function defects and can even cause intracranial hemorrhage in severe cases. The brain tissue is prone to infarction when hemodynamic equilibrium is affected. In addition, bypass vessels become susceptible to occlusion or atrophy when blood resistance increases. Even compression of the temporalis affects bypass vessels. Because the STA is used in MMD surgery, the scalp becomes ischemic and is likely to develop necrosis and infection. These complications of MMD surgery are difficult to manage and are not well understood. To date, no systematic studies of the complications that occur after direct bypass in MMD have been performed, and reported complications are hidden among various case studies; therefore, this paper presents a review and summary of the literature in PubMed on the complications of direct bypass in MMD.

Research Progress of Moyamoya Disease in Children

During the onset of Moyamoya disease (MMD), progressive occlusion occurs at the end of the intracranial internal carotid artery, and compensatory net-like abnormal vessels develop in the skull base, generating the corresponding clinical symptoms. MMD can affect both children and adults, but MMD in pediatric patients exhibits distinct clinical features, and the treatment prognoses are different from adult patients. Children are the group at highest risk for MMD. In children, the disease mainly manifests as ischemia, while bleeding is the primary symptom in adults. The pathogenesis of MMD in children is still unknown, and some factors are distinct from those in adults. MMD in children could result in progressive, irreversible nerve functional impairment, and an earlier the onset corresponds to a worse prognosis. Therefore, active treatment at an early stage is highly recommended. The treatment methods for MMD in children mainly include indirect and direct surgeries. Indirect surgeries mainly include multiple burr-hole surgery (MBHS), encephalomyosynangiosis (EMS), and encephaloduroarteriosynangiosis (EDAS); direct surgeries mainly include intra- and extracranial vascular reconstructions that primarily consist of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. Indirect surgery, as a treatment for MMD in children, has shown a certain level of efficacy. However, a standard treatment approach should combine both indirect and direct procedures. Compared to MMD in adults, the treatment and prognosis of MMD in children has higher clinical significance. If the treatment is adequate, a satisfactory outcome is often achieved.

Moyamoya disease and syndromes: from genetics to clinical management

Moyamoya angiopathy is characterized by a progressive stenosis of the terminal portion of the internal carotid arteries and the development of a network of abnormal collateral vessels. This chronic cerebral angiopathy is observed in children and adults. It mainly leads to brain ischemic events in children, and to ischemic and hemorrhagic events in adults. This is a rare condition, with a marked prevalence gradient between Asian countries and Western countries. Two main nosological entities are identified. On the one hand, moyamoya disease corresponds to isolated moyamoya angiopathy, defined as being “idiopathic” according to the Guidelines of the Research Committee on the Pathology and Treatment of Spontaneous Occlusion of the Circle of Willis. This entity is probably multifactorial and polygenic in most patients. On the other hand, moyamoya syndrome is a moyamoya angiopathy associated with an underlying condition and forms a very heterogeneous group with various clinical presentations, various modes of inheritance, and a variable penetrance of the cerebrovascular phenotype. Diagnostic and evaluation techniques rely on magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) conventional angiography, and cerebral hemodynamics measurements. Revascularization surgery can be indicated, with several techniques. Characteristics of genetic moyamoya syndromes are presented, with a focus on recently reported mutations in BRCC3/MTCP1 and GUCY1A3 genes. Identification of the genes involved in moyamoya disease and several monogenic moyamoya syndromes unraveled different pathways involved in the development of this angiopathy. Studying genes and pathways involved in monogenic moyamoya syndromes may help to give insights into pathophysiological models and discover potential candidates for medical treatment strategies.

[Learning vascular microsurgical techniques on an animal model]

INTRODUCTION

The aim of this study was to assess the progress of an operator, during microsurgical training, on a bilateral carotid revascularization in the rat.

MATERIAL AND METHODS

In this prospective study, nine rats underwent bilateral carotid revascularization. An end-to-end graft of the right carotid artery by the facial vein and an end-to-side bypass of left carotid artery by the jugular external vein were performed. Anastomoses were carried out with 10/0 thread, based on the technique of the symmetric bi-angulation. At the end of procedure, a permeability test was performed on each anastomosis. Duration of survival of the animal, permeability of anastomosis, and evolution of the operating periods during the training were collected and respectively analyzed with a Fisher's and Student's t tests. In cases of procedure success, anastomoses were remotely controlled and a brain dissection was performed in order to seek a possible ischemia due to carotid clamping. In the event of failure, the rat was sacrificed and anastomoses were opened in order to establish the cause of thrombosis.

RESULTS

Two thirds of the revascularization procedures were successful. A total of 83.3% of the anastomoses were patent. Of the six rats preserved for remote evaluation of anastomoses, three died. Remotely controlled anastomoses remained all permeable. No cerebral ischemia, associated with carotid clamping (approximately 45 minutes), was highlighted by brain dissection. With the growing experience of the operator, an improvement in results in mastery of the technique was objectively observed. Operative durations were reduced between the beginning and the end of the training: -54 minutes (P=0.001).

CONCLUSION

Microsurgical laboratory training seems to be essential in order to acquire the dexterity, ease and experience necessary for performing microsurgical procedures in humans.

Cerebral arteriopathy associated with Arg179His ACTA2 mutation

ACTA2 mutations have recently been shown to cause a multisystem smooth muscle dysfunction syndrome that may result in pediatric stroke. We report a case of ACTA2 mutation in a 3-year-old girl presenting with acute ischemic stroke and provide high resolution imaging of the cerebral arteries demonstrating novel findings of multiple tiny aneurysms (particularly in the posterior circulation), as well as the more characteristic imaging phenotype of straightened and narrowed proximal intracranial vessels, dilated cervical vessels and occlusion of the M1 MCA segment without lenticulostriate collateral formation. This newly identified disease should be added to the differential diagnosis of pediatric stroke and cerebral vasculopathy. Neuroradiologists, interventionalists, surgeons and neurologists should become familiar with this rare disease and its clinical sequelae.

Cerebral arteriopathy associated with Arg179His ACTA2 mutation

ACTA2 mutations have recently been shown to cause a multisystem smooth muscle dysfunction syndrome that may result in pediatric stroke. We report a case of ACTA2 mutation in a 3-year-old girl presenting with acute ischemic stroke and provide high resolution imaging of the cerebral arteries demonstrating novel findings of multiple tiny aneurysms (particularly in the posterior circulation), as well as the more characteristic imaging phenotype of straightened and narrowed proximal intracranial vessels, dilated cervical vessels and occlusion of the M1 MCA segment without lenticulostriate collateral formation. This newly identified disease should be added to the differential diagnosis of pediatric stroke and cerebral vasculopathy. Neuroradiologists, interventionalists, surgeons and neurologists should become familiar with this rare disease and its clinical sequelae.

Thalassemia and the hypercoagulable state

Thalassemia, an inherited hemolytic disorder, is associated with a high incidence of thrombosis. The major mechanisms underlying thromboembolism (TE) are an abnormal red blood cell surface, platelet activation and endothelial cell activation. A higher risk of TE is found in splenectomized patients due to thrombocytosis and increased abnormal RBCs in the circulation. Regular RBC transfusions can reduce the proportion of abnormal RBCs and suppress erythropoiesis. Regular transfusion may also reduce levels of circulating coagulation markers and reduce elevated pulmonary artery pressure. To prevent thromboembolic events, aspirin is now recommended for splenectomized patients with thrombocytosis.

A novel distinctive cerebrovascular phenotype is associated with heterozygous Arg179 ACTA2 mutations

Mutations in the ACTA2 gene lead to diffuse and diverse vascular diseases; the Arg179His mutation is associated with an early onset severe phenotype due to global smooth muscle dysfunction. Cerebrovascular disease associated with ACTA2 mutations has been likened to moyamoya disease, but appears to have distinctive features. This study involved the analysis of neuroimaging of 13 patients with heterozygous missense mutations in ACTA2 disrupting Arg179. All patients had persistent ductus arteriosus and congenital mydriasis, and variable presentation of pulmonary hypertension, bladder and gastrointestinal problems associated with this mutation. Distinctive cerebrovascular features were dilatation of proximal internal carotid artery, occlusive disease of terminal internal carotid artery, an abnormally straight course of intracranial arteries, and absent basal 'moyamoya' collaterals. Patterns of brain injury supported both large and small vessel disease. Key differences from moyamoya disease were more widespread arteriopathy, the combination of arterial ectasia and stenosis and, importantly, absence of the typical basal 'moyamoya' collaterals. Evaluation of previously published cases suggests some of these features are also seen in the ACTA2 mutations disrupting Arg258. The observation that transition from dilated to normal/stenotic arterial calibre coincides with where the internal carotid artery changes from an elastic to muscular artery supports the hypothesis that abnormal smooth muscle cell proliferation caused by ACTA2 mutations is modulated by arterial wall components. Patients with persistent ductus arteriosus or congenital mydriasis with a label of 'moyamoya' should be re-evaluated to ensure the distinctive neuroimaging features of an ACTA2 mutation have not been overlooked. This diagnosis has prognostic and genetic implications, and mandates surveillance of other organ systems, in particular the aorta, to prevent life-threatening aortic dissection.