Meta-analysis of the surgical outcomes of symptomatic moyamoya disease in adults

Exploration of the risk factor for infarction after revascularization in moyamoya disease

RESULTS

Eventually, 108 consecutive patients received 174 surgeries were enrolled, experienced new or expanded infarction occured in 13 (7.47%) surgeries, which showed higher Suzuki stage on the non-operative side, more posterior cerebral artery (PCA) involvement, and more intraoperative hypotension compared to those without infarction(p < .05). The Suzuki stage on the non-operative side had the highest area under the curve (AUC) of 0.737, with a sensitivity of 0.692 and specificity of 0.783. Combination of the three factors showed better efficiency, with an AUC of 0.762, a sensitivity of 0.692, and a specificity of 0.907.

CONCLUSIONS

Revascularization was a safe option for patients with MMD, higher Suzuki stage on the non-operative side, PCA involvement, and intraoperative hypotension might be the risk factors for new or expanded infarction after revascularization in patients with MMD.

Influence of an improvement in frontal lobe hemodynamics on neurocognitive function in adult patients with moyamoya disease

BACKGROUND

In adults, moyamoya disease (MMD) often presents with slight neurocognitive impairment, which may result from frontal lobe hemodynamic insufficiency.

METHODS

In this study, we performed revascularization surgery by superficial temporal artery-anterior cerebral artery (ACA) direct bypass in 20 adults with MMD with poor anterograde ACA flow (Group M). The pre- and postoperative neurocognitive test results of these patients were retrospectively analyzed. The comparative group (Group C) included 23 patients with unruptured aneurysms or brain tumors who underwent craniotomy, as well as the same neurocognitive tests as Group M. We calculated the compositive frontal lobe function index (CFFI) based on the results of seven neurocognitive tests for each patient, and the difference between the pre- and postoperative CFFI values (CFFI Post - Pre) was compared between the two groups.

RESULTS

Frontal perfusion improved postoperatively in all patients in Group M. The CFFI Post - Pre was significantly higher in Group M than in Group C (0.23 ± 0.44 vs. - 0.20 ± 0.32; p < 0.001). After adjusting for postoperative age, sex, preoperative non-verbal intelligence quotient, and preoperative period of stress, Group M had a significantly higher CFFI Post - Pre than Group C in the multiple regression analysis (t value = 4.01; p < 0.001).

CONCLUSION

Improving frontal lobe hemodynamics might be the key for improving neurocognitive dysfunction in adults with MMD. The surgical indication and method should be considered from the perspective of both stroke prevention and neurocognitive improvement or protection.

Effective Smartphone Application Use for Postoperative Management of Moyamoya Disease

Continuous and careful management is necessary after revascularization surgery for moyamoya disease (MMD). The postoperative information has been shared in person or by telephone and emails among doctors; however, this is not always efficient. We aimed to describe the feasibility of remote diagnosis and text chats using a smartphone application on postoperative MMD management. Twenty consecutive patients who underwent combined direct and indirect revascularization for MMD were prospectively investigated in this study. In ten patients, the operator viewed postoperative images uploaded on a smartphone screen using the Join application (Allm Inc., Tokyo, Japan). The doctors shared the radiological findings and treatment plans using the group text chat function and performed postoperative management. We evaluated the intermodality agreements of radiological findings between the smartphone screen and conventional viewer. Postoperative courses were compared between the two patient groups that used or did not use the application. All postoperative images were uploaded to the cloud server and the operator viewed them remotely on the smartphone screen without restriction of location. Detected abnormal findings were cerebral hyperperfusion (CHP), CHP-related watershed shift phenomenon, fluid-attenuated inversion recovery cortical hyperintensity, high signal intensity on diffusion-weighted imaging, CHP-related crossed cerebellar diaschisis, and hypoperfusion. Radiological agreement between the modalities was good in all cases, and additional findings were not obtained on the conventional viewer. The postoperative courses of the Join group were as good as those of the control group. Remote radiological diagnosis and text chat using a smartphone application were feasible and useful for efficient and safe postoperative MMD management.

Moyamoya syndrome in a patient with D-2-hydroxyglutaric aciduria type II: a rare association

PURPOSE

Several underlying conditions of moyamoya syndrome (MMS) are well established, but so far, D-2-hydroxyglutaric aciduria (D-2-HGA) has not been mentioned. We are the first to describe a case of a patient suffering from D-2-HGA developing MMS.

METHODS

The co-occurrence of D-2-HGA and MMS in a patient is reported. Furthermore, we describe the neurosurgical revascularization procedure performed and report on the follow-up.

RESULTS

A 7-year-old girl suffering from D-2-HGA developed two transient ischemic attacks (TIAs). Using MRI/MRA and invasive angiography MMS was diagnosed. We performed an encephalo-duro-arterio-myo-synangiosis (EDAMS) as an indirect revascularization procedure first on the right and 2 months later on the left hemisphere. We have followed her up until the age of 10. Since the second surgery, she has not suffered further TIAs and is in a better general medical condition.

CONCLUSION

Even though children with D-2-HGA often suffer epileptic attacks, every new (transient) neurological deficit should be followed up by an MRI/MRA so as not to oversee a possible underlying MMS. After diagnosis, EDAMS in combination with acetylsalicylic acid (ASA) is recommended to prevent further ischemic events.

Outcomes of Bypass Surgery in Adult Moyamoya Disease by Onset Type

Importance

Moyamoya disease (MMD) is a rare chronic cerebrovascular disease, and the outcomes of bypass management in adult patients remain controversial.

Objective

To categorize adult MMD based on asymptomatic, ischemic, and hemorrhagic onset and compare the outcomes (death, hemorrhagic stroke [HS], and ischemic stroke [IS]) of bypass surgery (direct or indirect) with those of conservative management.

Design, Setting, and Participants

This retrospective, nationwide, population-based longitudinal cohort study used Korean National Health Insurance Research data to identify adults (aged ≥15 years) with MMD who were diagnosed between January 1, 2008, and December 31, 2020, and followed up until December 31, 2021 (median follow-up, 5.74 [IQR, 2.95-9.42] years). A total of 19 700 participants (3194 with hemorrhagic, 517 with ischemic, and 15 989 with asymptomatic MMD) were included. Data were analyzed from January 2 to April 1, 2023.

Exposures

Bypass surgery and conservative management.

Main Outcomes and Measures

Death constituted the primary outcome; secondary outcomes consisted of HS or IS. Kaplan-Meier survival curve and Cox proportional hazards regression analysis were applied. The propensity score-matching and stratified analyses were performed to control covariate effects.

Results

A total of 19 700 patients (mean [SD] age, 45.43 [14.98] years; 12 766 [64.8%] female) were included. Compared with conservative management, bypass was associated with a reduced risk of death (adjusted hazard ratio [AHR], 0.50 [95% CI, 0.41-0.61]; P < .001) and HS (AHR, 0.36 [0.30-0.40]; P < .001) in hemorrhagic MMD; reduced risk of IS (AHR, 0.55 [95% CI, 0.37-0.81]; P = .002) in ischemic MMD; and reduced risk of death (AHR, 0.74 [95% CI, 0.66-0.84]; P < .001) in asymptomatic MMD. However, bypass was associated with an increased risk of HS (AHR, 1.76 [95% CI, 1.56-2.00]; P < .001) in asymptomatic MMD. Both direct and indirect bypass demonstrated similar effects in hemorrhagic and asymptomatic MMD, except only direct bypass was associated with a reduced risk of IS (AHR, 0.52 [95% CI, 0.33- 0.83]; P = .01) in ischemic MMD. After stratification, bypass was associated with a reduced risk of death in patients younger than 55 years with ischemic (AHR, 0.34 [95% CI, 0.13- 0.88]; P = .03) and asymptomatic (AHR, 0.69 [95% CI, 0.60-0.79]; P < .001) MMD, but an increased risk of HS in patients 55 years or older with ischemic MMD (AHR, 2.13 [95% CI, 1.1-4.16]; P = .03).

Conclusions and Relevance

The findings of this cohort study of bypass outcomes for patients with MMD emphasize the importance of tailoring management strategies in adult patients based on onset types.

Predictive value of the hemispheric magnetic resonance angiography score on the development of indirect pial synangiosis after combined revascularization surgery for adult moyamoya disease

PURPOSE

It is difficult to precisely predict indirect bypass development in the context of combined bypass procedures in moyamoya disease (MMD). We aimed to investigate the predictive value of magnetic resonance angiography (MRA) signal intensity in the peripheral portion of the major cerebral arteries for indirect bypass development in adult patients with MMD.

METHODS

We studied 93 hemispheres from 62 adult patients who underwent combined direct and indirect revascularization between 2005 and 2019 and genetic analysis for RNF213 p.R4810K. The signal intensity of the peripheral portion of the major intracranial arteries during preoperative MRA was graded as a hemispheric MRA score (0-3 in the middle cerebral artery and 0-2 in the anterior cerebral and posterior cerebral arteries, with a high score representing low visibility) according to each vessel's visibility. Postoperative bypass development was qualitatively evaluated using MRA, and we evaluated the correlation between preoperative factors, including the hemispheric MRA score and bypass development, using univariate and multivariate analyses.

RESULTS

A good indirect bypass was observed in 70% of the hemispheres. Hemispheric MRA scores were significantly higher in hemispheres with good indirect bypass development than in those with poor indirect bypass development (median: 3 vs. 1; p < 0.0001). Multiple logistic regression analysis revealed hemispheric MRA score as an independent predictor of good indirect bypass development (odds ratio, 2.1; 95% confidence interval, 1.3-3.6; p < 0.01). The low hemispheric MRA score (< 2) and wild-type RNF213 predicted poor indirect bypass development with a specificity of 0.92.

CONCLUSION

Hemispheric MRA score was a predictive factor for indirect bypass development in adult patients who underwent a combined bypass procedure for MMD. Predicting poor indirect bypass development may lead to future tailored bypass surgeries for MMD.

Predictors of Stroke Outcomes in Conservatively Treated Patients With Moyamoya Disease: A Follow-up MRI Study

BACKGROUND

Little is known about the association between stroke and imaging and clinical features in conservatively treated patients with moyamoya disease (MMD).

PURPOSE

To investigate independent risk factors for stroke in conservatively treated patients with MMD during a long-term follow-up.

STUDY TYPE

Prospective study.

SUBJECTS

One hundred sixty conservatively managed patients with MMD (median age 46 years, 89 male).

FIELD STRENGTH/SEQUENCE

Time of flight, turbo inversion recovery magnitude T1WI, turbo spin echo (TSE) T2WI, echo-planar imaging DWI, T2-fluid attenuated inversion recovery, dynamic susceptibility contrast-magnetic resonance imaging, and pre- and post-contrast 3D TSE T1WI sequences at 3.0 Tesla.

ASSESSMENT

Patients were assessed at baseline and followed yearly. Ischemic and hemorrhagic stroke incidence rates were determined. Multiple demographic, clinical (modified Rankin score [mRS]), and cerebral imaging (cerebral blood volume [CBV] and concentric enhancement of arterial wall) factors at baseline were considered as potential predictors of stroke during the follow-up period.

STATISTICAL TESTS

Univariable and multivariable Cox proportional hazards models to calculate the hazard ratios (HRs) and corresponding 95% confidence interval (CI) for stroke. Cumulative risk of stroke was estimated by the Kaplan-Meier product-limit method. A P value <0.05 was considered statistically significant.

RESULTS

The median follow-up duration was 47 months. During the follow-up period, 18 (11.25%) patients experienced stroke events (13 [8.13%] ischemic, 5 [3.12%] hemorrhagic). Univariable analysis showed that 11 factors were significantly associated with stroke. After adjustment for clinical characteristics, multivariable analysis showed that mRS score ≥3 (HR, 1.99; 95% CI, 1.26-3.14), decreased CBV (HR, 5.31; 95% CI, 2.32-12.13), and concentric enhancement of the arterial wall (HR, 4.16; 95% CI, 1.55-11.15) were significantly associated with stroke.

DATA CONCLUSION

Decreased CBV, mRS score ≥ 3, and concentric enhancement of the arterial wall were significantly associated with increased incidence of stroke in conservatively treated MMD.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 4.

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.

Remote ischemic conditioning after stroke: Research progress in clinical study

BACKGROUND AND PURPOSE

Stroke is a leading cause of global morbidity and mortality, indicating the necessity and urgency of effective prevention and treatment. Remote ischemic conditioning (RIC) is a convenient, simple, non-intrusive, and effective method that can be easily added to the treatment regime of stroke patients. Animal experiments and clinical trials have proved the neuroprotective effects of RIC on brain injury including (examples of neuroprotective effects). This neuroprotection is achieved by raising brain tolerance to ischemia, increasing local cerebral blood perfusion, promoting collateral circulations, neural regeneration, and reducing the incidence of hematomas in brain tissue. This current paper will summarize the studies within the last 2 years for the comprehensive understanding of the use of RIC in the treatment of stroke.

METHODS

This paper summarizes the clinical research progress of RIC on stroke (ischemic stroke and hemorrhagic stroke (HS)). This paper is a systematic review of research published on registered clinical trials using RIC in stroke from inception through November 2022. Four major databases (PUBMED, WEB OF SCIENCE, EMBASE, and ClinicalTrials.gov) were searched.

RESULTS

Forty-eight studies were identified meeting our criteria. Of these studies, 14 were in patients with acute ischemic stroke with onset times ranging from 6 h to 14 days, seven were in patients with intravenous thrombolysis or endovascular thrombectomy, 10 were in patients with intracranial atherosclerotic stenosis, six on patients with vascular cognitive impairment, three on patients with moyamoya disease, and eight on patients with HS. Of the 48 studies, 42 were completed and six are ongoing.

CONCLUSIONS

RIC is safe, feasible, and effective in the treatment of stroke. Large-scale research is still required to explore the optimal treatment options and mechanisms of RIC in the future to develop a breakthrough in stroke prevention and treatment.

Future of Endovascular and Surgical Treatments of Atherosclerotic Intracranial Stenosis

Intracranial atherosclerotic disease and resultant intracranial stenosis is a global leading cause of stroke, and poses an ongoing treatment challenge. Among patients with intracranial stenosis, those with hemodynamic compromise are at high risk for recurrent stroke despite medical therapy and risk factor modification. Revascularization of the hypoperfused territory is the most plausible treatment strategy for these high-risk patients, yet surgical and endovascular therapies have not yet shown to be sufficiently safe and effective in randomized controlled trials. Advances in diagnostic and therapeutic technologies have led to a resurgence of interest in surgical and endovascular treatment strategies, with a growing body of evidence to support their further evaluation in the treatment of select patient populations. This review outlines the current and emerging endovascular and surgical treatments and highlights promising future management strategies.

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.

[Moyamoya disease in adults: treatment methods in modern era]

Moyamoya angiopathy is a chronic progressive cerebrovascular disease characterized by stenosis and occlusion of the distal segments of the internal carotid arteries and/or proximal segments of the middle and anterior cerebral arteries, with a gradual compensatory restructuring of the cerebral circulation to the system of the external carotid arteries. Today, the main treatment method for Moyamoya angiopathy is surgical revascularization of the brain. A search and analysis of publications on the treatment of adult patients with Moyamoya angiopathy was carried out in the PubMed and Medscape databases over the past 10 years. We present a case of an adult female patient with a hemorrhagic form of Moyamoya angiopathy stage IV according to J. Suzuki, who underwent staged combined revascularization of both cerebral hemispheres. Surgical revascularization included the creation of a low-flow extra-intracranial shunt combined with a combination of indirect synangiosis. The combination of direct and indirect methods of surgical revascularization enables to achieve the development of an extensive network of collaterals and fully compensate for cerebral circulatory disorders both in the early and late postoperative periods, which is confirmed by instrumental diagnostic data. Combined revascularization is the most effective modern method of treating patients with Moyamoya angiopathy due to the complementary influence of direct and indirect components of revascularization.

Development and External Validation of Nomogram for Cerebral Infarction in Moyamoya Diseases

More than 60% of moyamoya disease (MMD) patients suffers cerebral ischemia and preoperative cerebral infarction (CI) increases the risk of postoperative stroke and unfavorable outcome. We established a nomogram system for risk stratification of CI to help tailoring individualized management. We enrolled 380 patients including 680 hemispheres for the training cohort from our hospital and 183 patients including 348 hemispheres for the validation cohort from multicenter. A nomogram for CI was formulated based on the multivariable logistic regression analysis. The predictive accuracy and discriminative ability of nomogram were determined with concordance index (C-index) and calibration curve. For the training cohort, 246 hemispheres (36.2%) were found with CI. In multivariable logistic regression used generalized estimating equations approach, anterior choroidal artery (AchA) grade (grade 1, OR 0.214, 95%CI 0.124-0.372, P < 0.001; grade 2, OR 0.132, 95%CI 0.066-0.265, P < 0.001), cerebral perfusion (OR 4.796, 95%CI 2.922-7.872; P < 0.001), white matter hyperintensity (OR 3.652, 95%CI 1.933-6.902; P < 0.001), brush sign (OR 3.555, 95%CI 2.282-5.538; P < 0.001), and ivy sign (equivocal, OR 4.752, 95%CI 2.788-8.099, P < 0.001; present, OR 8.940, 95%CI 4.942-16.173, P < 0.001) were significant factors for CI. The C-index of the nomogram for predicting cerebral infarction was 0.890 (95%CI 0.866-0.915) in the training cohort and 0.847 (95%CI 0.805-0.889) in the validation cohort. The nomogram composed of AchA grade, cerebral perfusion, white matter hyperintensity, brush sign, and ivy sign could provide risk stratification of CI before surgery in patients with MMD. Active treatment might be recommended before CI, which could reduce the risk of stroke after surgery.

Association of Bypass Surgery and Mortality in Moyamoya Disease

Background Patients with moyamoya disease (MMD) have a high risk of stroke or death. We investigated whether extracranial to intracranial bypass surgery can reduce mortality by preventing strokes in patients with MMD. Methods and Results This nationwide retrospective cohort study encompassed patients with MMD registered under the Rare Intractable Diseases program via the Relieved Co-Payment Policy between 2006 and 2019, using the Korean National Health Insurance Service database. Following a 4-year washout period, landmark analyses were employed to assess mortality and stroke occurrence between the bypass surgery group and the nonsurgical control group at specific time points postindex date (1 month and 3, 6, 12, and 36 months). The study included 18 480 patients with MMD (mean age, 40.7 years; male to female ratio, 1:1.86) with a median follow-up of 5.6 years (interquartile range, 2.5-9.3; mean, 6.1 years [SD, 4.0 years]). During 111 775 person-years of follow-up, 265 patients in the bypass surgery group and 1144 patients in the nonsurgical control group died (incidence mortality rate of 618.1 events versus 1660.3 events, respectively, per 105 person-years). The overall adjusted hazard ratio (HR) revealed significantly lower all-cause mortality in the bypass surgery group from the 36-month landmark time point, for any stroke mortality from 3- and 6-month landmark time points, and for hemorrhagic stroke mortality from the 6-month landmark time point. Furthermore, the overall adjusted HRs for hemorrhagic stroke occurrence were beneficially maintained from all 5 landmark time points in the bypass surgery group. Conclusions Bypass surgery in patients with MMD was associated with a lower risk of all-cause and hemorrhagic stroke mortality and hemorrhagic stroke occurrence compared with nonsurgical control.

Evaluation of surgical revascularization procedure outcomes for adult Moyamoya disease: a computed tomography perfusion-based study

BACKGROUND

The effectiveness of surgical interventions, whether direct or indirect, for Moyamoya disease (MMD) remains controversial. This study aims to investigate CT perfusion (CTP) as an objective method to evaluate the outcomes of different surgical modalities for adult MMD.

METHODS

The clinical and imaging data of 41 patients who underwent superficial temporal artery-middle cerebral artery (STA-MCA) bypass and 43 who received encephaloduroarteriosynangiosis (EDAS) were retrospectively analyzed. Intra- and intergroup differences in the Modified Rankin Scale (mRS) score, the change in clinical symptoms, collateral grade, and CTP parameters pre- and postoperatively were compared.

RESULTS

The overall level of the change in clinical symptoms in the STA-MCA group was higher than in the EDAS group (p < 0.05). In the operative area, the relative cerebral blood flow (rCBF) was significantly higher whereas the relative time to peak (rTTP) and the relative mean transit time (rMTT) were significantly lower in the STA-MCA and EDAS groups postoperatively than preoperatively (all p < 0.05). In the ipsilateral frontal lobe and basal ganglia, the postoperative rCBF was significantly higher, and the rTTP was significantly lower than the preoperative in the STA-MCA group (all p < 0.05). The postoperative rCBF improvement was higher in each brain area for STA-MCA than in the EDAS group (all p < 0.05).

CONCLUSION

Highlighting the utility of CTP, this study demonstrates its effectiveness in assessing postoperative cerebral hemodynamic changes in adult MMD patients. STA-MCA yielded a larger postoperative perfusion area and greater improvement compared to EDAS, suggesting CTP's potential to elucidate symptom variation between two surgical revascularization procedures.

CRITICAL RELEVANCE STATEMENT

We analyzed computed tomography perfusion parameters in pre- and postoperative adult Moyamoya disease patients undergoing superficial temporal artery-middle cerebral artery bypass and encephaloduroarteriosynangiosis. Our findings suggest computed tomography perfusion's potential in objectively elucidating symptom variations between these surgical revascularization approaches for MMD.

KEY POINTS

• Postoperative perfusion improvement is only confined to the operative area after EDAS. • Besides the operative area, postoperative perfusion in the ipsilateral frontal lobe and basal ganglia was also improved after STA-MCA. • The degree of perfusion improvement in each brain area in the STA-MCA group was generally greater than that in the EDAS group.

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

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

Chronological Volume Changes of the Temporal Muscle Pedicle Used for Encephalo-myo-synangiosis in Combined Revascularization for Moyamoya Disease: A Prospective Observational Study

Although postoperative neurological events due to brain compression by the swollen temporal muscle are a rare complication, the chronological volume changes of the temporal muscle pedicle and their clinical impact have not yet been documented. This prospective observational study aimed to investigate the chronological volume changes in the temporal muscle pedicle in Moyamoya disease (MMD). Eighteen consecutive combined revascularization procedures using the temporal muscle were performed for symptomatic MMD in 2021. The postoperative pedicle volume was quantified using repeated computed tomography images on postoperative days (PODs) 0, 1, 7, 14, and 30. Postoperative neurological events with radiological evaluations and collateral development evaluated using magnetic resonance angiography obtained 6 months after surgery were studied. On average, the postoperative temporal muscle pedicle volume was most significantly increased by as much as 112% ± 9.6% on POD 7 (P < 0.001) and decreased by as little as 52% ± 21% on POD 30 (P < 0.0001) relative to POD 0. One exceptional patient (overall incidence, 5.6%) demonstrated postoperative transient neurological events due to brain compression by the swollen temporal muscle with decreased focal cerebral blood flow in the adjacent cortical area. The postoperative collateral development via direct and indirect revascularizations was confirmed in 16 (89%) and 12 (67%) hemispheres, respectively. All patients, except for one rebleeding case, showed independent outcomes at the mean latest follow-up period on 290 ± 96 days after surgery. Our observations confirmed the temporal profile of muscle pedicle volume changes after combined revascularization. Through routine attempts to avoid the unfavorable effects of temporal muscle swelling, combined revascularization can provide favorable outcomes in symptomatic MMD.

The Development and Effect of Systemic Hypertension on Clinical and Radiological Outcome in Adult Moyamoya Angiopathy Following Revascularization Surgery: Experience of a Single European Institution

Patients with Moyamoya Angiopathy (MMA) display structurally altered vessels with decreased cerebral autoregulatory capacity, so aggressive lowering of systemic hypertension may aggravate ischemic symptoms, whereas uncontrolled hypertension may promote hemorrhage. This study provides an in-depth analysis of the role of hypertension in adult MMA patients including long-term analysis of clinical and radiological development. In this single-center retrospective analysis of 137 adult MMA patients with 206 surgically treated hemispheres angiographic images, clinical/operative data were reviewed and scored. Univariate Cox-regression analysis was performed to evaluate hypertension as a predictor for negative angiographic and clinical outcomes following revascularization surgery. A total of 50% of patients were being treated for hypertension prior to the first surgery. Patients with and without hypertension did not differ in terms of age, gender, diagnosis, symptom onset or disease severity (Berlin and Suzuki Grades). Although hypertension did not statistically significantly affect postoperative collaterals, moyamoya vessels or STA-MCA bypass patency, patients with hypertension showed higher rates of bypass patency and better bypass filling compared to those without hypertension. No significant differences in adverse events were found in patients with and without systemic hypertension and the presence of systemic hypertension was not found to predict negative clinical or radiological outcomes. In conclusion, the rate of systemic hypertension in MMA patients appears to be higher than the general population; however, this is not associated with an increased risk of postoperative complications or negative angiographic development following revascularization procedures. Systemic hypertension may also positively influence the rate of bypass patency and filling following revascularization procedures.

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.

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.

Follow-up outcomes of different bypass surgical modalities for adults with ischaemic-type moyamoya disease

PURPOSE

The preferred surgical method for treating adults with moyamoya disease (MMD) remains controversial. The purpose of this study was to compare the efficacy of different surgical methods in the treatment of adults with ischaemic-type MMD.

METHODS

We retrospectively analyzed the data of patients with ischaemic-type MMD who underwent indirect bypass (IB), direct bypass (DB), or combined bypass (CB) at the First Affiliated Hospital of Zhengzhou University from January 2013 to December 2019. Postoperative complications, improvements in neurological function, haemodynamics, recurrent stroke and neovascularization were compared.

RESULTS

A total of 310 adults (371 hemispheres) with ischaemic-type MMD were included in our study. Ninety, 127, and 154 hemispheres underwent IB, DB and CB, respectively. A total of 24 (6.5%) ischaemic events and 8 (2.8%) symptomatic hyperperfusion events occurred after the operations. There was no significant difference in postoperative complications among the three types of surgery (p = 0.300). During the follow-up period, there were 21 cases (5.7%) of recurrent ischaemia and 12 cases (3.2%) of recurrent haemorrhage. Kaplan-Meier survival analysis showed that the ischaemia-free survival of the CB group was significantly longer than that of the IB group (p = 0.047), but there was no significant difference in haemorrhage-free survival among the three groups (p = 0.660). Six months after the operation, DB and CB were superior to IB in improving cerebral blood flow and neovascularization (p = 0.002), but there was no significant difference in the improvement of neurological function among the three groups at the last follow-up (p = 0.784).

CONCLUSION

The three surgical methods achieved satisfactory results in the treatment of ischaemic-type MMD. DB and CB can significantly improve haemodynamics and reduce recurrent stroke. In terms of improving neurological function, the curative effect of the three surgical methods remains to be further explored.

Expression of hypoxia-inducing factor-1α and matrix metalloproteinase-9 in the recipient parasylvian cortical arteries with different hemodynamic sources in adult moyamoya disease

Objective

In our latest research, we have demonstrated that the recipient parasylvian cortical arteries (PSCAs) with hemodynamic sources from the middle cerebral artery (M-PSCAs) has a higher risk of postoperative cerebral hyperperfusion (CHP) syndrome than those from non-M-PSCAs in adult moyamoya disease (MMD) patient. However, whether there are differences between M-PSCAs and non-M-PSCAs in vascular specimens characteristics has not been studied. In this study, we further investigate the vascular specimen of recipient PSCAs by histological and immunohistochemical methods.

Methods

50 vascular specimens of recipient PSCAs were obtained from 50 adult MMD patients during the combined bypass surgeries in our departments of Zhongnan hospital. 4 recipient PSCAs samples were also obtained in the same way from the middle cerebral artery occlusion patients. The samples were received the pathological sectioning, hematoxylin and eosin staining, and immunohistochemistry, then the vascular wall thickness, matrix metalloproteinase-9 (MMP-9) and hypoxia-inducing factor-1α (HIF-1α) were analyzed.

Results

M-PSCAs adult MMD patients had a thinner intima than non-M-PSCAs in the recipient PSCAs specimens. In recipient non-M-PSCAs vascular specimens, the immunoreactivity indicating HIF-1α and matrix metalloproteinase-9 (MMP-9) was significantly higher than M-PSCAs groups. The logistic regression analyses showed that the M-PSCAs was an independent risk factor of postoperative cerebral hyperperfusion (CHP) syndrome (OR 6.235, 95% CI1.018-38.170, P = 0.048) in MMD.

Conclusion

Our results indicate that M-PSCAs adult MMD patients had thinner intima than non-MCAs adult MMD patients in the PSCAs. More importantly, HIF-1α and MMP-9 were overexpressed in non-M-PSCAs vascular specimens.

Nomogram to Predict Good Collateral Formation After the STA-MCA Bypass Surgery in Adult Patients With Moyamoya Disease

BACKGROUND

Collateral formation from the extracranial carotid artery to ischemic brain tissue determines the clinical success of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery in adult patients with moyamoya disease, but postoperative collateral formation (PCF) after STA-MCA bypass surgery is unpredictable. Accurate preoperative prediction of acceptable PCF could improve patient selection. This study aims to develop a prediction nomogram model for PCF in this patient population.

METHODS

Adult patients with moyamoya disease undergoing the STA-MCA bypass surgery between January 2013 and December 2020 at a single institution were retrospectively or prospectively enrolled in this observational study. Data including potential clinical and radiological predictors were obtained from hospital records. A nomogram was generated based on a multivariate logistic regression analysis, to identify potential predictors associated with good PCF. The performance of the nomogram was evaluated for discrimination, calibration, and clinical utility.

RESULTS

Data from 243 patients with moyamoya disease who underwent the STA-MCA bypass surgery were analyzed to build the nomogram. After 1-year follow-up, 162 (66.7%) hemispheres had good PCF and 81 (33.3%) had poor PCF. Good PCF is associated with 3 preoperative factors: age at operation, a diameter of donor branch of STA, and the preinfarction period stage. Incorporating these 3 factors, the model achieved a concordance index of 0.88 (95% CI, 0.84-0.92) and had a well-fitted calibration curve and good clinical application value. A cutoff value of 100 was determined to predict good PCF via this nomogram.

CONCLUSIONS

The nomogram exhibits high accuracy in predicting good PCF after the STA-MCA bypass surgery in adult patients with moyamoya disease and may allow surgeons to better evaluate preoperatively candidacy for successful bypass surgery.

European Stroke Organisation (ESO) Guidelines on Moyamoya angiopathy: Endorsed by Vascular European Reference Network (VASCERN)

The European Stroke Organisation (ESO) guidelines on Moyamoya Angiopathy (MMA), developed according to ESO standard operating procedure and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, were compiled to assist clinicians in managing patients with MMA in their decision making. A working group involving neurologists, neurosurgeons, a geneticist and methodologists identified nine relevant clinical questions, performed systematic literature reviews and, whenever possible, meta-analyses. Quality assessment of the available evidence was made with specific recommendations. In the absence of sufficient evidence to provide recommendations, Expert Consensus Statements were formulated. Based on low quality evidence from one RCT, we recommend direct bypass surgery in adult patients with haemorrhagic presentation. For ischaemic adult patients and children, we suggest revascularization surgery using direct or combined technique rather than indirect, in the presence of haemodynamic impairment and with an interval of 6–12 weeks between the last cerebrovascular event and surgery. In the absence of robust trial, an Expert Consensus was reached recommending long-term antiplatelet therapy in non-haemorrhagic MMA, as it may reduce risk of embolic stroke. We also agreed on the utility of performing pre- and post- operative haemodynamic and posterior cerebral artery assessment. There were insufficient data to recommend systematic variant screening of RNF213 p.R4810K. Additionally, we suggest that long-term MMA neuroimaging follow up may guide therapeutic decision making by assessing the disease progression. We believe that this guideline, which is the first comprehensive European guideline on MMA management using GRADE methods will assist clinicians to choose the most effective management strategy for MMA.

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.

Larger Posterior Revascularization Associated with Reduction of Choroidal Anastomosis in Moyamoya Disease: A Quantitative Angiographic Analysis

BACKGROUND AND PURPOSE

Choroidal anastomosis, a hemorrhage-prone periventricular collateral manifestation in Moyamoya disease, outflows to the cortex posterior to the central sulcus. The objective of the present study was to test whether the angiographic extent of revascularization posterior to the central sulcus contributes to the postoperative reduction of choroidal anastomosis.

MATERIALS AND METHODS

This retrospective cohort study included choroidal anastomosis-positive hemispheres before direct bypass surgery. The postoperative reduction of choroidal anastomosis was determined by a consensus of 2 raters according to the previous research. An imaging software automatically traced the angiographic revascularization area, which was subsequently divided into anterior and posterior parts by an anatomic line corresponding to the central sulcus. Each area was quantitatively measured as a percentage relative to the whole supratentorial area.

RESULTS

Postoperative reduction of choroidal anastomosis was achieved in 68 (85.0%) of the 80 included hemispheres. The revascularization area posterior to the central sulcus was significantly larger in the hemispheres with reduction than in those with no reduction (mean, 15.2% [SD, 7.1%] versus 4.2% [SD, 3.4%], P < .001), whereas no significant difference was observed in the revascularization area anterior to the central sulcus. Multivariate analysis revealed that the revascularization area posterior to the central sulcus was the only significant factor associated with reduction (OR, 1.57; 95% CI, 1.21-2.03, for every 1% increase).

CONCLUSIONS

The results suggest that a larger revascularization posterior to the central sulcus is associated with postoperative reduction of choroidal anastomosis regardless of the extent of anterior revascularization. It might facilitate optimal selection of the revascularization site for preventing hemorrhage.

Effect of Age, Stage, and Type of Surgical Revascularization on Clinical and Angiographic Outcome in Moyamoya Disease - Experience from a Case Series of 175 Revascularization Procedures

BACKGROUND

There is dearth of literature on impact of age - pediatric versus adult, Suzuki staging - early versus late, and revascularization type - indirect versus direct on clinical and angiographic outcome in moyamoya disease (MMD). Hence, we intend to comprehensively evaluate factors influencing outcome in MMD following surgical revascularization.

METHODS

MMD patients operated at our institute from January 2011 to August 2018 were followed for an average 24 months. Primary outcomes were modified Rankin score (mRS) and stroke risk reduction. Secondary outcome was angiographic outcome score (AOS).

RESULTS

A total of 133 patients including 37.6% adults (>18 years; n = 50) underwent 175 revascularizations - 89 direct (DR) and 86 indirect (IR) subgroups. Mean mRS scores improved in pediatric DR (P < 0.001), IR (P < 0.001), adult IR (P = 0.10), and DR (P = 0.25) subgroups. Recurrent stroke rate was similar in pediatric-DR (2.7%) and IR (7.6%, P = 0.61), and adult-DR (0%) and IR (4.1%) subgroups (P = 1.00). AOS scores improved in pediatric DR (P = 0.002) and IR (P = 0.01), and adult-DR (P = 0.02) and IR (P = 0.06) subgroups. Late-stage MMD (Suzuki IV-VI) showed better improvement in mRS scores than early-stage-Suzuki (I-III; P < 0.001). Recurrent stroke rates were similar (P = 0.26) and AOS scores improved significantly in early- and late-stage MMD (P < 0.001).

CONCLUSIONS

In pediatrics, clinical and angiographic outcome significantly improved after revascularization procedure, and in adults, angiographic improvement was more evident than clinical recovery. Late-stage Suzuki MMD patients demonstrated significantly better clinical improvement than early stage. The angiographic improvement was equivalent to early stage, irrespective of age and type of revascularization.

Influence of Autologous Bone Marrow Stem Cell Therapy on the Levels of Inflammatory Factors and Conexin43 of Patients with Moyamoya Disease

Moyamoya disease is a medical condition that shows the typical characteristics like continuous and chronic thickening of the walls and the contraction of the internal carotid artery; as a result, the internal diameter of the artery gets narrowed. There are six phases of the disease ranging from I to VI (moyamoya vessels completely disappear, followed by the complete blockage of the arteries). Surgery is a commonly recommended treatment for the moyamoya disease. Our research study identifies the effect of autologous bone marrow stem cell therapy (ABMSCT) on the levels of inflammatory factors and Conexin43 (Cx43) protein in patients suffering from moyamoya. In our study, we have selected 52 moyamoya patients admitted to our hospital from 30 July 2019 to 10 February 2020. The control group (CG) was treated with superficial temporal artery to a middle cerebral artery (STA-MCA) bypass + encephalo-duro-myosinangiosis (EDMS). The experimental group (Exp. Grp) was treated with ABMSC. The cerebral vascular tissue of the patients was treated with hematoxylin-eosin (HE) staining. Immunohistochemical staining was used to identify the levels of Cx43 protein. The concentrations of vascular endothelial growth factor (VEGF), inflammatory factor interleukin-6 (IL6), interleukin-1β (IL1β), tumor necrosis factor (TNFα), and anti-inflammatory factor interleukin-1β (IL1β) were determined by enzyme-linked immunosorbent assay (ELISA). We have found that after treatment of the expression of Cx43 protein, the proportions of grade IV (7.7%), grade III (311.5%), and grade II (3.8%) patients in the Exp. Grp were lower than those in the CG. The proportion of grade I patients in the Exp. Grp (77%) was higher than that in the CG (38.5%). After treatment, the inflammatory factors IL6 (0.97 ± 0.82 pg/mL), IL1β (8.33 ± 1.21 pg/mL), and TNFα (1.73 ± 0.71 pg/mL) in the Exp. Grp were lower than those in the CG. The anti-inflammatory factor IL1β (15.09 ± 4.72 pg/mL) increased in the Exp. Grp compared with the CG (11.25 ± 3.48 pg/mL) post treatment. Intracranial infection, hydrocephalus, hemiplegia, and transient neurological dysfunction in the Exp. Grp were lower than those in the CG, with statistical differences (P < 0.05). Our study suggests that the treatment of autologous bone marrow stem cells (ABMSC) was beneficial to balance the inflammatory response of disorders, reduce the damage of vascular tissue in the brain, and regulate tissue repair by co-acting with various inflammatory factors as compared to traditional surgery. We conclude that the involvement of Cx43 in the occurrence and development of moyamoya. We also have found that the risk factors of intracranial infection after ABMSCT were less as compared to those after conventional surgery.

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.

Angiographic Characteristics of Cerebral Perfusion and Hemodynamics of the Bridging Artery After Surgical Treatment of Unilateral Moyamoya Disease

Purpose

To investigate the characteristics of cerebral perfusion and hemodynamics of bypass grafting in the treatment of moyamoya disease (MMD) using the iFlow color-coded flow map in comparison with magnetic resonance imaging–perfusion-weighted imaging (MRI–PWI) and computational fluid dynamic (CFD) analysis.

Materials and Methods

Patients with MMD treated with bypass grafting who had undergone MRI PWI and digital subtraction angiography for iFlow color-coded map was retrospectively enrolled and CFD was performed for calculating the hemodynamic stresses around the bypass grafting.

Results

Forty-five patients with unilateral MMD treated with bypass surgery were enrolled. The bypass surgery was successful in all patients, with no severe neurological complications during the periprocedural period. Followed up for 4–12 months (median 5.5), the neurological function was good in all patients. The cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time to peak (TTP) were significantly (p < 0.05) improved in the middle cerebral artery distribution area on the surgical side before and after vascular bypass, and the difference of TTP (s) measured from the proximal bifurcation of common carotid artery to the confluence of sinus was also significant (p < 0.05). A significant (p < 0.05) positive correlation existed in the perfusion parameters between the iFlow blood perfusion and the MRI–PWI perfusion, with r-value for TTP of 0.765 (p < 0.01). The iFlow color-coded blood flow map showed warm color changes on the diseased side, similar to those on the contralateral side. In CFD analysis, the hemodynamic stresses were all improved, in and around the bypass grafting and distal vessels, which were beneficial to blood flow entering distal arterial branches.

Conclusion

The iFlow color-coded flow map can be used to analyze cerebral perfusion after bypass grafting for MMD, similar to MRI–PWI, and CFD can be used to analyze the hemodynamics after bypass grafting, revealing improved hemodynamics to promote blood flow entering distal arteries.

Identification of associations and distinguishing moyamoya disease from ischemic strokes of other etiologies: A retrospective case-control study

Introduction

Better characterizing moyamoya disease (MMD) from ischemic strokes of other etiologies may facilitate earlier diagnosis by raising suspicion for a diagnostic work-up.

Methods

To identify associated variables, MMD cases (n = 12) were compared against three sets of controls: age-, sex-, and race-matched controls of patients with general neurological disorders (n = 48), unmatched general controls (n = 48), and unmatched non-MMD ischemic stroke controls (n = 48).

Results

MMD patients were 32 years (p < 0.0001) younger than ischemic stroke controls. Relative to non-MMD ischemic strokes, MMD patients had greater odds of presenting with visual field defects (OR: 9.13, p = 0.09) or dizziness (OR: 9.13, p = 0.09), as well as being female (OR: 8.04, p = 0.008), Asian (OR: 3.68, p = 0.087), employed (OR: 6.96, p = 0.02), having migraines (OR: 21.61, p = 0.005), epilepsy (OR: 6.69, p = 0.01), insomnia (OR: 8.90, p = 0.099), and a lower Charlson Comorbidity Index (CCI; p = 0.002). Patients with MMD, compared to non-MMD ischemic strokes, also had a 4.67 kg/ m2 greater body mass index (BMI) and larger odds (OR relative to normal BMI: 21.00, p = 0.03) of being from obesity class III (>40 kg/ m2), yet reduced odds of coronary artery disease (OR: 0.13, p = 0.02). Relative to general controls, MMD patients had greater odds of diabetes mellitus type 2 (OR: 10.07, p = 0.006) and hypertension (OR: 7.28, p = 0.004).

Conclusion

MMD not only has a unique clinical presentation from other ischemic strokes, but also unique comorbidities, which may facilitate earlier work-up and treatment.

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Moyamoya patients are 32 years younger than ischemic strokes of other etiologies.

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Moyamoya patients are 4.67 kg/ m2 heavier than those with ischemic strokes.

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Moyamoya patients are at greater odds of type 2 diabetes mellitus and hypertension.

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Moyamoya patients are at reduced odds of coronary artery disease.

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Moyamoya patients present more often with visual field deficits or dizziness.

Association between Cognitive Decline and Altered Cerebral Perfusion in Adults with Moyamoya Disease after Revascularization

INTRODUCTION

Certain studies have observed that patients with moyamoya disease (MMD) have cognitive decline after revascularization. Thus, this study analyzed the relationship between cognitive decline and altered cerebral perfusion after revascularization.

METHODS

Here, 313 adult patients with MMD underwent single unilateral revascularization. First, cognitive function was scored using a Mini-Mental Scale (MMSE) and Montreal cognitive function scale (MoCA) before and 3 months after the operation (superficial temporal artery-middle cerebral artery anastomosis with encephalo-myo-synangiosis). Then, computed tomography perfusion was performed before and 1 week after the operation to assess the cerebral perfusion.

RESULTS

Our data showed that cognitive function decreased in 55 cases (17.6%) after revascularization. Furthermore, the incidence of cerebral hyperperfusion (CHP) was significantly higher in the cognitive decline group (49/55) than in the cognitive nondecline group (89.1% vs. 5.4%, p < 0.001). Results also showed that although all 55 patients had postoperative cognitive decline, 47 experienced relative cerebral blood flow (CBF) decrease at a relatively distant area of the anastomosis compared with that before the operation, which was significantly higher than in patients without cognitive decline (85.5% vs. 1.94%, p < 0.001). In addition, 41 patients had a simultaneous occurrence of local CHP and paradoxical CBF decrease at a relatively distant anastomosis area, which indicated the incident of watershed shift (WS). As observed, WS occurred in 74.5% of patients with cognitive decline, significantly higher than in patients without cognitive decline (74.5% vs. 0%, p < 0.0001). Through multiple logistic regression analysis, WS was also observed to be a strong independent risk factor for predicting postoperative cognitive decline 3 months after revascularization (odds ratio 17.780, 95% confidence interval 1.668-18.564; p = 0.017).

CONCLUSION

Therefore, cognitive decline in patients with MMD after revascularization is related to WS, leading to an uneven distribution of CBF.

Infarction Patterns and Recurrent Adverse Cerebrovascular Events in Moyamoya Disease

For moyamoya disease (MMD) patients who suffered an acute ischemic attack, the infarction patterns on DWI and its association with recurrent adverse cerebrovascular events (ACEs) after bypass surgery remain unknown. 327 patients who suffered an acute ischemic attack and received following revascularization surgery were retrospectively reviewed and were divided into three patterns according to the lesion number and distribution on DWI that obtained within 7 days of onset: no acute infarction (NAI), single acute infarction (SAI), and multiple acute infarctions (MAIs). We used Cox proportional hazard models to estimate hazard ratios (HR) for associations of infarction patterns and the risk of recurrent ACEs and strokes. Over a median follow-up of 41 months (IQR 26-60), there were 61 ACEs and 27 strokes. Compared to the NAI cohort, patients with SAI (HR, 2.92; 95% CI, 1.41-6.05; p = 0.004) and MAIs (HR, 4.44; 95% CI, 2.10-9.41; p < 0.001) were associated with higher risk of ACEs recurrences. In analysis adjusted for age and surgery modalities, the corresponding HR was 2.90 (95% CI: 1.41-5.98) for SAI and 4.10 (95% CI: 1.95-8.63) for MAIs, and this effect remained persistent on further adjustment for several potential confounders. Similar but less precise association was found in separate analysis that only takes into account stroke recurrences. Thus, different infarction patterns on DWI imply different risks of recurrent ACEs, and more attention should be paid to prevent ACEs in MMD patients with MAIs.

Superficial temporal artery lengthening technique to prevent postoperative wound complications in direct revascularization to the anterior cerebral artery for Moyamoya disease

BACKGROUND

Neurocognitive dysfunctions or psychomotor symptoms of Moyamoya disease may improve after direct revascularization to the anterior cerebral artery (ACA). However, long-distance harvest of the frontal branch of the superficial temporal artery (STA) is needed to reach the cortical ACA, frequently resulting in postoperative wound complications. To solve this problem, we devised a novel method (STA lengthening technique). In this study, we compared the STA lengthening technique and the conventional method regarding postoperative wound complications.

METHODS

Twenty-five patients who underwent STA-ACA direct bypass from December 2016 to October 2021 were retrospectively reviewed, and postoperative wound complications were recorded. Magnetic resonance angiography was performed to evaluate the patency of the bypass to the ACA and postoperative development of collaterals to the skin flap.

RESULTS

Thirty-eight hemispheres (new method [n = 12] vs. conventional method [n = 26]) were treated. Wound complications occurred in 12 surgeries (46%) of the conventional method, and none (0%) of the new method. The anastomosis with the cortical ACA was patent in all surgeries. Postoperative development of collaterals to the skin flap was confirmed after all surgeries (100%) in the new method, whereas after only five surgeries (20%) in the conventional method.

CONCLUSION

The STA lengthening technique can enable to preserve the collateral circulation to the skin flap postoperatively, resulting in good wound healing.

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.

Moyamoya Disease-Standards and Advances in Revascularization Procedure and Peri-operative Management

Moyamoya disease (MMD) is a chronic, occlusive cerebrovascular disease with unknown etiology characterized by progressive stenosis at the terminal portion of the internal carotid artery and the abnormal vascular network formation at the base of the brain. Superficial temporal artery-middle cerebral artery (STA-MCA) bypass is a preferred surgical procedure for ischemic-onset MMD patients by improving cerebral blood flow. Recent evidence further indicates that flow-augmentation bypass has a potential role for preventing re-bleeding in hemorrhagic-onset MMD patients. Based on such cumulative evidence, there is a worldwide increase in the number of MMD patients undergoing bypass surgery, thus thorough understanding of the basic pathology of MMD including peri-operative hemodynamics is critical for avoiding surgical complications. The author sought to demonstrate the standard surgical procedure of STA-MCA bypass with indirect pial synangiosis for adult MMD patients and its pitfall in the early postoperative period, introducing the characteristic peri-operative hemodynamic condition of adult MMD after surgery, such as local cerebral hyperperfusion and intrinsic hemodynamic ischemia caused by watershed shift phenomenon.

Daily Remote Ischemic Conditioning Can Improve Cerebral Perfusion and Slow Arterial Progression of Adult Moyamoya Disease—A Randomized Controlled Study

Background and Purpose

Moyamoya disease (MMD) is a complicated cerebrovascular disease with recurrent ischemic or hemorrhagic events. This study aimed to prove the safety and efficacy of remote ischemic conditioning (RIC) on MMD.

Methods

In total, 34 patients with MMD participated in this pilot, prospective randomized controlled study for 1 year. 18 patients were allocated into the RIC group, and 16 patients accepted routine medical treatment only. RIC-related adverse events were recorded. The primary outcome was the improvement ratio of mean cerebral blood flow (mCBF) in middle cerebral artery territory measured by multidelay pseudocontinuous arterial spin labeling, and the secondary outcomes were the cumulative incidence of major adverse cerebrovascular events (MACEs), the prevalence of stenotic-occlusive progression, and periventricular anastomosis at 1-year follow-up.

Results

In total, 30 of the 34 patients with MMD completed the final follow-up (17 in the RIC group and 13 in the control group). No adverse events of RIC were observed. The mCBF improvement ratio of the RIC group was distinctively higher compared with the control group (mCBF−whole-brain: 0.16 ± 0.15 vs. −0.03 ± 0.13, p = 0.001). Stenotic-occlusive progression occurred in 11.8% hemispheres in the RIC group and 38.5% in the control group (p = 0.021). The incidence of MACE was 5.9% in the RIC group and 30.8% in the control group (hazard ratio with RIC, 0.174; 95% CI, 0.019–1.557; p = 0.118). No statistical difference was documented in the periventricular anastomosis between the two groups after treatment.

Conclusions

Remote ischemic conditioning has the potential to be a safe and effective adjunctive therapy for patients with MMD largely due to improving cerebral blood flow and slowing the arterial progression of the stenotic-occlusive lesions. These findings warrant future studies in larger trials.

Macrohistory of Moyamoya Disease Analyzed Using Artificial Intelligence

INTRODUCTION

Moyamoya disease is characterized by progressive stenotic changes in the terminal segment of the internal carotid artery and the development of abnormal vascular networks called moyamoya vessels. The objective of this review was to provide a holistic view of the epidemiology, etiology, clinical findings, treatment, and pathogenesis of moyamoya disease. A literature search was performed in PubMed using the term "moyamoya disease," for articles published until 2021.

RESULTS

Artificial intelligence (AI) clustering was used to classify the articles into 5 clusters: (1) pathophysiology (23.5%); (2) clinical background (37.3%); (3) imaging (13.2%); (4) treatment (17.3%); and (5) genetics (8.7%). Many articles in the "clinical background" cluster were published from the 1970s. However, in the "treatment" and "genetics" clusters, the articles were published from the 2010s through 2021. In 2011, it was confirmed that a gene called Ringin protein 213 (RNF213) is a susceptibility gene for moyamoya disease. Since then, tremendous progress in genomic, transcriptomic, and epigenetic profiling (e.g., methylation profiling) has resulted in new concepts for classifying moyamoya disease. Our literature survey revealed that the pathogenesis involves aberrations of multiple signaling pathways through genetic mutations and altered gene expression.

CONCLUSION

We analyzed the content vectors in abstracts using AI, and reviewed the pathophysiology, clinical background, radiological features, treatments, and genetic peculiarity of moyamoya disease.

Prolonged/delayed cerebral hyperperfusion in adult patients with moyamoya disease with RNF213 gene polymorphism c.14576G>A (rs112735431) after superficial temporal artery-middle cerebral artery anastomosis

OBJECTIVE

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is the standard surgical management for moyamoya disease (MMD), whereas cerebral hyperperfusion (CHP) is one of the potential complications of this procedure that can result in delayed intracerebral hemorrhage and/or neurological deterioration. Recent advances in perioperative management in the early postoperative period have significantly reduced the risk of CHP syndrome, but delayed intracerebral hemorrhage and prolonged/delayed CHP are still major clinical issues. The clinical implication of RNF213 gene polymorphism c.14576G>A (rs112735431), a susceptibility variant for MMD, includes early disease onset and a more severe form of MMD, but its significance in perioperative pathology is unknown. Thus, the authors investigated the role of RNF213 polymorphism in perioperative hemodynamics after STA-MCA anastomosis for MMD.

METHODS

Among 96 consecutive adult patients with MMD comprising 105 hemispheres who underwent serial quantitative cerebral blood flow (CBF) analysis by N-isopropyl-p-[123I]iodoamphetamine SPECT after STA-MCA anastomosis, 66 patients consented to genetic analysis of RNF213. Patients were routinely maintained under strict blood pressure control during and after surgery. The local CBF values were quantified at the vascular territory supplied by the bypass on postoperative days (PODs) 1 and 7. The authors defined the radiological CHP phenomenon as a local CBF increase of more than 150% compared with the preoperative values, and then they investigated the correlation between RNF213 polymorphism and the development of CHP.

RESULTS

CHP at POD 1 was observed in 23 hemispheres (23/73 hemispheres [31.5%]), and its incidence was not statistically different between groups (15/41 [36.6%] in RNF213-mutant group vs 8/32 [25.0%] in RNF213-wild type (WT) group; p = 0.321). CHP on POD 7, which is a relatively late period of the CHP phenomenon in MMD, was evident in 9 patients (9/73 hemispheres [12.3%]) after STA-MCA anastomosis. This prolonged/delayed CHP was exclusively observed in the RNF213-mutant group (9/41 [22.0%] in the RNF213-mutant group vs 0/32 [0.0%] in the RNF213-WT group; p = 0.004). Multivariate analysis revealed that RNF213 polymorphism was significantly associated with CBF increase on POD 7 (OR 5.47, 95% CI 1.06-28.35; p = 0.043).

CONCLUSIONS

Prolonged/delayed CHP after revascularization surgery was exclusively found in the RNF213-mutant group. Although the exact mechanism underlying the contribution of RNF213 polymorphism to the prolonged/delayed CBF increase in patients with MMD is unclear, the current study suggests that genetic analysis of RNF213 is useful for predicting the perioperative pathology of patients with MMD.

Progression in Moyamoya Disease: Clinical Feature, Neuroimaging Evaluation and Treatment

Moyamoya disease (MMD) is a chronic cerebrovascular disease characterized by progressive stenosis of the arteries of the circle of Willis, with the formation of collateral vascular network at the base of the brain. Its clinical manifestations are complicated. Numerous studies have attempted to clarify the clinical features of MMD, including its epidemiology, genetic characteristics, and pathophysiology. With the development of neuroimaging techniques, various neuroimaging modalities with different advantages have deepened the understanding of MMD in terms of structural, functional, spatial, and temporal dimensions. At present, the main treatment for MMD focuses on neurological protection, cerebral blood flow reconstruction, and neurological rehabilitation, such as pharmacological treatment, surgical revascularization, and cognitive rehabilitation. In this review, we discuss recent progress in understanding the clinical features, in the neuroimaging evaluation and treatment of MMD.

The angiographic presentation of European Moyamoya angiopathy

Background and purpose

Little is known about the angiographic presentation of Moyamoya angiopathy (MMA) in non-Asian patients.

Methods

Conventional cerebral angiograms from 155 Caucasian patients diagnosed as MMA were analyzed with respect to extracranial champagne bottle neck sign, Suzuki stages, collateral status, as well as presence of aneurysms and posterior cerebral artery stenosis.

Results

In 84 of 155 angiograms, the extracranial carotid artery was visualized, in 65 of them (77.4%), a champagne bottle neck sign was noted. Of the 278 analyzable hemispheres, 13.7%,11.2%, 37.8%, 27.3%, 8.6%, and 1.4% were classified as Suzuki stage I, stage II, stage III, stage IV, stage V, and stage VI, respectively. Among 280 hemispheres, in 53 hemispheres (18.9%) isolated basal collaterals (pathway I) and in 104 hemispheres (37.1%) choroidal and pericallosal collaterals (including basal collaterals, pathway II) were found. In 74 hemispheres (26.4%) ethmoidal collaterals (pathways III), and in 17 hemispheres (6.1%) vault collaterals were visualized. Patients with higher Suzuki stages IV–VI (p = 0.008) and ethmoidal collaterals (p < 0.001) suffered more often from cerebral hemorrhage. Transient ischemic attacks occurred more frequently in patients with Suzuki stage I to III (p < 0.001). In 10 of 155 patients (6.5%), the angiogram revealed a cerebral aneurysm. In 13 patients (8.4%), a stenotic P1 segment of the posterior cerebral artery was found.

Conclusions

This is so far the largest observational study about angiography in Caucasian European MMA patients. A comparison with Asian data indicates similarity of disease in Caucasian and Asian patients.

Surgical Management of Failed Revascularization in Moyamoya Vasculopathy

Objectives: Moyamoya vasculopathy (MMV) is a rare stenoocclusive cerebrovascular disease associated with increased risk of ischemic and hemorrhagic stroke, which can be treated using surgical revascularization techniques. Despite well-established neurosurgical procedures performed in experienced centers, bypass failure associated with neurological symptoms can occur. The current study therefore aims at characterizing the cases of bypass failure and repeat revascularization at a single center.

Methods: A single-center retrospective analysis of all patients treated with revascularization surgery for MMV between January 2007 and December 2019 was performed. Angiographic data, cerebral blood flow analysis [H₂O PET or single-photon emission CT (SPECT)], MRI, and clinical/operative data including follow-up assessments were reviewed.

Results: We identified 308 MMV patients with 405 surgically treated hemispheres. Of the 405 hemispheres treated, 15 patients (3.7%) underwent repeat revascularization (median age 38, time to repeat revascularization in 60% of patients was within 1 year of first surgery). The most common cause of repeat revascularization was a symptomatic bypass occlusion (80%). New ischemic lesions were found in 13% of patients prior to repeat revascularization. Persistence of reduced or progressive worsening of cerebrovascular reserve capacity (CVRC) compared with preoperative status was observed in 85% of repeat revascularization cases. Intermediate-flow bypass using a radial artery graft was most commonly used for repeat revascularization (60%) followed by re-superficial temporal artery to middle cerebral artery (re-STA-MCA) bypass (26%). High-flow bypass using a saphenous vein graft and using an occipital artery to MCA bypass was each used once. Following repeat revascularization, no new ischemic events were recorded.

Conclusion: Overall, repeat revascularization is needed only in a small percentage of the cases in MMV. A rescue surgery should be considered in those with neurological symptoms and decreased CVRC. Intermediate-flow bypass using a radial artery graft is a reliable technique for patients requiring repeat revascularization. Based on our institutional experience, we propose an algorithm for guiding the decision process in cases of bypass failure.

Implementation and Rationale for a Unified Clinical and Imaging Protocol for Evaluation and Treatment of Moyamoya Angiopathy: A Single Institutional Experience

Moyamoya disease (MMD) is a complex and incompletely-understood cerebrovascular pathological entity that requires thorough clinical and imaging evaluation. Moyamoya is rare, thereby making the establishment of an effective, thorough and interdisciplinary patient evaluation protocol challenging, even within specialized referral centers. Nevertheless, implementation of such a protocol is crucial in order to provide the best possible evaluation and treatment for MMD patients. Here, we describe our institution's implementation of, rationale for, and experience with a comprehensive multidisciplinary collaboration and evaluation strategy for adult patients with moyamoya. This evaluation course consists of, first of all, a thorough clinical and laboratory evaluation with a vascular neurologist. This is followed by a comprehensive imaging assessment which evaluates angiographic and parenchymal features, in addition to cerebrovascular functionality. Finally, appropriate referrals are made to consulting services as indicated, which includes vascular neurosurgery. These steps are described in detail herein.

Encephaloduroarteriosynangiosis (EDAS) treatment of moyamoya syndrome: evaluation by computed tomography perfusion imaging

OBJECTIVE

To explore the value of computed tomography perfusion (CTP) imaging for evaluating the efficacy of encephaloduroarteriosynangiosis (EDAS) treatment of moyamoya syndrome (MMS).

METHODS

Forty-three patients with MMS (48 hemispheres) who received EDAS treatment were examined using CTP and DSA before and after surgery. CTP of the ipsilateral cortex, contralateral mirror area, and pons region were measured, and the relative cerebral blood flow (rCBF) and volume (rCBV), mean transit time (rMTT), and time-to-peak (rTTP) were calculated. Based on postoperative DSA, 48 hemispheres were apportioned to two groups based on rich (grades 2, 3) or poor (grades 0, 1) collateral vessel formation, and the pre- and post-operative differences in perfusion changes were compared. The association between clinical outcome, CTP, and the degree of DSA collateral vessels was explored.

RESULTS

rCBF and rMTT significantly improved in both the poor and rich collateral vessel formation groups (n = 21 and 27, respectively), while rTTP significantly improved only in the latter. Postoperative CTP improved in the rich and the grade 1 collateral vessel groups (p < 0.01). The clinical improvement was consistent with the improvement of CTP (p = 0.07), but less consistent with the degree of collateral angiogenesis (p = 0.003).

CONCLUSION

CTP can quantitatively evaluate the improvement of brain tissue perfusion in the operated area after EDAS. Brain tissue perfusion in operated areas improved regardless of postoperative rich or poor collateral vessel formation observed via DSA. A significant improvement in rTTP in the operated area may indicate the formation of abundant collateral vessels.

KEY POINTS

• CTP showed that brain tissue perfusion in the operated area after EDAS improved regardless of rich or poor collateral vessel formation observed via DSA. • Significant improvement of rTTP in the operated area may indicate the formation of abundant collateral vessels.

Direct versus indirect bypass procedure for the treatment of ischemic moyamoya disease: results of an individualized selection strategy

OBJECTIVE

The only effective treatment for ischemic moyamoya disease (iMMD) is cerebral revascularization by an extracranial to intracranial bypass. The preferred revascularization method remains controversial: direct versus indirect bypass. The purpose of this study was to test the hypothesis that method choice should be personalized based on angiographic, hemodynamic, and clinical characteristics to balance the risk of perioperative major stroke against treatment efficacy.

METHODS

Patients with iMMD were identified retrospectively from a prospectively maintained database. Those with mild to moderate internal carotid artery or M1 segment stenosis, preserved cerebrovascular reserve, intraoperative M4 segment anterograde flow ≥ 8 ml/min, or the absence of frequent and severe transient ischemic attacks (TIAs) or stroke had been assigned to indirect bypass. The criteria for direct bypass were severe ICA or M1 segment stenosis or occlusion, impaired cerebrovascular reserve or steal phenomenon, intraoperative M4 segment retrograde flow or anterograde flow < 8 ml/min, and the presence of frequent and severe TIAs or clinical strokes. The primary study endpoint was MRI-confirmed symptomatic stroke ≤ 7 days postoperatively resulting in a decline in the modified Rankin Scale (mRS) score from preoperatively to 6 months postoperatively. As a secondary endpoint, the authors assessed 6-month postoperative DSA-demonstrated revascularization, which was classified as < 1/3, 1/3-2/3, or > 2/3 of the middle cerebral artery territory.

RESULTS

One hundred thirty-eight patients with iMMD affecting 195 hemispheres revascularized in the period from March 2016 to June 2018 were included in this analysis. One hundred thirty-three hemispheres were revascularized with direct bypass and 62 with indirect bypass. The perioperative stroke rate was 4.7% and 6.8% in the direct and indirect groups, respectively (p = 0.36). Degree of revascularization was higher in the direct bypass group (p = 0.03). The proportion of patients improving to an mRS score 0-1 (from preoperatively to 6 months postoperatively) tended to be higher in the direct bypass group, although the difference between the two bypass groups was not statistically significant (p = 0.27).

CONCLUSIONS

The selective use of an indirect bypass procedure for iMMD did not decrease the perioperative stroke rate. Direct bypass provided a significantly higher degree of revascularization. The authors conclude that direct bypass is the treatment of choice for iMMD.

Ipsilateral late stroke after revascularization surgery for patients with Moyamoya disease

BACKGROUND

Ipsilateral late stroke events occurring after cerebral revascularization for Moyamoya disease (MMD) and their risk factors have not been fully investigated.

METHODS

We retrospectively analyzed 123 patients with MMD who underwent 212 revascularizations. We investigated preoperative demographic data, surgical procedures, and ipsilateral stroke events occurring more than 1 month after surgery. The effect of revascularization and the residual Moyamoya vessel (MMV) score were examined using magnetic resonance angiography (MRA). Then, predictive factors for postoperative late stroke occurrence were evaluated by logistic regression.

RESULTS

The mean age was 26 ± 18.4 years (range 1 to 66 years). Ipsilateral late stroke events were present in 11 of 123 (9%) patients. Stroke occurred in 11 out of 212 surgeries (5.2%) on a hemispheric basis. During the 1300.1 hemisphere-years of follow-up more than 1 month after surgery, the annual stroke rate was 0.84%. The postoperative MRA time-of-flight image showed a mean revascularization score of 1.82 ± 0.6 and a mean residual MMV score of 1.91 ± 0.83. Postoperative strokes occurring within 1 month after cerebral revascularization (36.4%, p = 0.0026) and lower revascularization scores (1.82 ± 0.6 vs 2.51 ± 0.59, p = 0.0006) were significant factors related to the presence of ipsilateral late stroke. Logistic regression showed that stroke events within 1 month after revascularization (odds ratio [OR], 9.79; 95% confidence interval [CI], 0.02-0.57; p = 0.0103), low revascularization score (OR, 0.15; 95% CI, 0.001-0.37; p = 0.0069), and high residual MMV score (OR, 16.2; 95% CI, 1.88-187.4; p = 0.0107) were risk factors for ipsilateral stroke more than 1 month after revascularization.

CONCLUSIONS

MMD patients who have a stroke within 1 month after cerebral revascularization are at high risk for late strokes. Less effective revascularization or remarkable residual MMV are risk factors for late stroke events. Additional revascularization may be considered for patients in such situations.

CLINICAL TRIAL REGISTRATION

This study was approved by the Bioethics Review Committee of Nagoya University Hospital for the treatment and prognosis of Moyamoya disease (2016-0327).

Contralateral improvement of cerebrovascular reactivity and TIA frequency after unilateral revascularization surgery in moyamoya vasculopathy

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Contralateral cerebrovascular reactivity may improve after unilateral surgery in moyamoya.

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TIA frequency from the contralateral hemisphere can decrease after unilateral moyamoya surgery.

•

These findings support staged rather than direct bilateral surgery in moyamoya.

Objective

Moyamoya vasculopathy is a rare, often bilateral disease characterized by progressive stenosis and occlusion of the distal internal carotid artery, leading to a progressive deterioration of cerebrovascular reactivity (CVR) and increased risk of transient ischemic attacks (TIAs), infarction and hemorrhage. Surgical revascularization is a widely accepted symptomatic treatment, often performed bilaterally in one or two stages. To possibly further optimize treatment strategy, we investigated the effect of unilateral revascularization surgery on the CVR of, and TIA frequency originating from, the contralateral hemisphere.

Methods

From our database of 143 moyamoya vasculopathy patients we selected those with bilateral disease, who underwent hemodynamic imaging ([15O]H2O positron emission tomography (PET)-CT with acetazolamide challenge) before and 14 months (median) after unilateral revascularization. We evaluated CVR in three regions per hemisphere, and averaged these per hemisphere for statistical comparison. Conservatively treated patients were showed as a comparison group. To examine TIA frequency, we selected patients who presented with TIAs that (also) originated from the contralateral – not to be operated – hemisphere. We scored changes in CVR and TIA frequency of the ipsilateral and contralateral hemisphere over time.

Results

Seven surgical and seven conservative patients were included for CVR comparison. Of the 20 scored contralateral regions in the surgical group, 15 showed improved CVR after unilateral revascularization, while 5 remained stable. The averaged scores improved significantly for both hemispheres. In conservatively treated patients, however, only 3 of the 20 scored regions improved in the least-affected (contralateral) hemispheres, and 9 deteriorated. From the 6 patients with contralateral TIAs at presentation, 4 had a decreased TIA frequency originating from the contralateral hemisphere after unilateral surgery, while 2 patients remained stable.

Conclusion

Both CVR and TIA frequency in the contralateral hemisphere can improve after unilateral revascularization surgery in bilateral MMV.