Edaravone Reduces Hyperperfusion-Related Neurological Deficits in Adult Moyamoya Disease

Systemic Immune-inflammation Index Is Associated with Symptomatic Cerebral Hyperperfusion after Revascularization Surgery in Moyamoya Disease

Revascularization surgery for moyamoya disease poses risks of complications, requiring appropriate management. Although precise prediction is difficult, the systemic immune-inflammation index is a calculable marker that reflects systemic inflammatory conditions. We aimed to investigate the association between postoperative complications and the systemic immune-inflammation index. We included 91 hemispheres from 71 patients who underwent combined revascularization surgery for moyamoya disease. Symptomatic cerebral hyperperfusion, radiological ischemic and hemorrhagic complications, and temporal muscle swelling that caused brain shift were assessed. The systemic immune-inflammation index ratio was calculated from blood test results from the preoperative day and the day after surgery. The association between the systemic immune-inflammation index ratio and postoperative complications was assessed using univariate and multivariate analyses. A receiver operating characteristic analysis was performed to evaluate the diagnostic value of the systemic immune-inflammation index ratio for postoperative complications. The frequencies of postoperative symptomatic cerebral hyperperfusion, ischemic and hemorrhagic complications, and temporal muscle swelling were detected in 24 (26%), 15 (16%), 11 (12%), and 5 (5%) hemispheres, respectively. The systemic immune-inflammation index ratio was higher in the group with postoperative complications than in the group without (median 4.6 vs. 2.7). Multivariate analysis demonstrated the systemic immune-inflammation index ratio as an independent factor associated with symptomatic cerebral hyperperfusion (odds ratio 2.4, 95% confidence interval 1.5-4.0). The receiver operating characteristic analysis demonstrated that the optimal threshold of the systemic immune-inflammation index ratio was 4.3, with a specificity of 0.96 and sensitivity of 0.63. The systemic immune-inflammation index ratio is an indicator of postoperative complications, including symptomatic cerebral hyperperfusion in moyamoya disease, and can be used for effective postoperative management.

Impact of RNF213 p.R4810K variant on postoperative temporal muscle swelling used in encephalo-myo-synangiosis after combined revascularization for Moyamoya disease

Postoperative neurological deterioration due to brain compression by the swollen temporal muscle pedicle used in encephalo-myo-synangiosis (EMS) is a potential complication of combined revascularization for Moyamoya disease (MMD). However, the factors contributing to this phenomenon remain poorly understood. This study aimed to identify factors associated with postoperative temporal muscle swelling following combined revascularization. A total of 37 consecutive combined revascularization using temporal muscle pedicle performed between 2021 and 2023 were analyzed. Postoperative temporal muscle volume was measured through serial CT scans on postoperative days (POD) 0, 1, 7, 14, and 30. Multiple regression analysis was performed to assess factors contributing to swelling, including RNF213 p.R4810K variant, a known genetic risk for Asian MMD. Surgical outcomes and collateral vessel development were also examined. Results showed a significant increase in muscle pedicle volume on POD 1 and 7 across all 37 hemispheres, followed by a marked decrease by POD 30, compared to POD 0. These chronological volume changes were significant in adults (n = 31) but not in pediatric patients (n = 6). Multiple regression analysis identified the RNF213 p.R4810K as sole significant factor positively associated with maximal muscle volume (regression coefficient 0.485, P = 0.0078). Favorable surgical outcomes were achieved in 36 of 37 cases (97.3%) over a mean follow-up of 2.2 years, with indirect collateral development confirmed in 27 adult (87%) and 6 pediatric (100%) hemispheres. Results suggest the RNF213 p.R4810K variant is associated with increased postoperative temporal muscle swelling after combined revascularization, especially in adult MMD patients, indicating a potential genetic influence on this complication.

Association between angiographic and clinical outcomes after STA-MCA bypass in adult moyamoya disease

BACKGROUND AND PURPOSE

As an angiographic outcome, postoperative collateral formation (PCF) is commonly used to evaluate the effect of STA-MCA bypass in moyamoya disease (MMD), but whether it can reliably reflect clinical outcomes is still unclear. We investigated the association between PCF and clinical outcomes in adult MMD.

METHODS

All STA-MCA bypass procedures performed from January 2013 to December 2019 were screened in this prospective cohort study. Patients who acquired presurgical and follow-up catheter angiography were included. The clinical outcomes consisted of symptom improvement and recurrent cerebrovascular events. Logistic and Cox regression and Kaplan-Meier analyses were performed to explore the association between PCF and clinical outcomes.

RESULTS

Of 165 included symptomatic hemispheres of 154 patients, 104 (63.0%) and 61 (37.0%) had good and poor PCF, respectively. The hemispheres with good PCF were younger (p = 0.004) and had a higher incidence of hemodynamic dysfunction on admission (p < 0.001) than those with poor PCF. Multivariate logistic regression analysis showed that the good PCF (odd ratio, 28.96; 95% confidence interval (CI), 9.12-91.98; p < 0.001) was associated with a higher incidence of symptom improvement. Multivariate Cox regression analysis showed that the poor PCF (hazard ratio, 3.77; 95% CI, 1.31-10.84; p = 0.014) was associated with a higher incidence of recurrent cerebrovascular events. In the hemorrhagic-onset hemispheres, good PCF group had a higher incidence of symptom improvement (p < 0.001) and a longer hemorrhage-free time (p = 0.031). In the ischemic-onset hemispheres, good PCF group also had a higher incidence of symptom improvement (p < 0.001) and a longer ischemia-free time (p = 0.028).

CONCLUSIONS

As a angiographic outcome, collateral formation is a qualified surrogate measure for clinical outcomes after STA-MCA bypass in adult MMD.

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.

Blood-brain barrier disruption imaging in postoperative cerebral hyperperfusion syndrome using DCE-MRI

Little has been reported about the association between cerebral hyperperfusion syndrome (CHS) and blood-brain barrier (BBB) disruption in human. We aimed to investigate the changes in permeability after bypass surgery in cerebrovascular steno-occlusive diseases using dynamic contrast-enhanced MRI (DCE-MRI) and to demonstrate the association between CHS and BBB disruption. This retrospective study included 36 patients (21 hemispheres in 18 CHS patients and 20 hemispheres in 18 controls) who underwent combined bypass surgery for moyamoya and atherosclerotic steno-occlusive diseases. DCE-MRI and arterial spin labeling perfusion-weighted imaging (ASL-PWI) were obtained at the baseline, postoperative state, and discharge. Perfusion and permeability parameters were calculated at the MCA territory (CBF(territorial), Ktrans(territorial), Vp(territorial)) and focal perianastomotic area (CBF(focal), Ktrans(focal), Vp(focal)) of operated hemispheres. As compared with the baseline, both CBF(territorial) and CBF(focal) increased in the postoperative period and decreased at discharge, corresponding well to symptoms in the CHS group. Vp(focal) was lower in the postoperative period and at discharge, as compared with the baseline. In the control group, no parameters significantly differed among the three points. In conclusion, Vp at the focal perianastomotic area significantly decreased in patients with CHS during the postoperative period. BBB disruption may be implicated in the development of CHS after bypass surgery.

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.

How I do it: combined bypass for adult moyamoya disease with maximal consideration of cosmetic aspects

BACKGROUND

Combined bypass, including direct and indirect procedures, has been recognized as the maximal revascularization to prevent further hemorrhagic or ischemic stroke in adult moyamoya disease (MMD). It is also important to consider cosmetic aspects when planning combined bypass for MMD. However, there are few reports that have described the cosmetic considerations in bypass surgery for MMD.

METHODS

We demonstrate our surgical techniques aimed at achieving extended revascularization as well as excellent cosmetic outcomes with figures and video.

CONCLUSION

Our combined bypass procedures which focus on achieving maximal cosmetic results are effective methods that require no special instruments or techniques.

Chinese expert consensus on the treatment of MMD

Moyamoya disease (MMD), also known as spontaneous occlusion of the circle of Willis, is defined by progressive stenosis or occlusion of the internal carotid arteries, and it can progress to the anterior, middle, and posterior cerebral arteries. As these arteries are gradually stenosed, a collateral network of capillaries develops at the base of the brain, producing the characteristic reticulate appearance ("puff of smoke") on angiography. Therefore, it was named by Suzuki and Takaku in 1969 after the Japanese term "moyamoya" (Suzuki and Takaku, Arch Neurol 20:288-299, 1969). MMD is most common in East Asian countries such as Japan and Korea, and it shows a slight female predominance. MMD is mainly characterized by ischemia and hemorrhage. Hemorrhagic MMD is very rare in children, and most cases occur in adults due to the rupture of the compensatory blood vessels, which often leads to hemorrhagic symptoms (Scott and Smith, N Engl J Med 360:1226-1237, 2009). In recent years, the diagnosis rate has increased with the popularization of imaging techniques. However, the pathogenesis of MMD is still not completely understood, and there is currently no evidence to suggest that drug treatment can delay or even reverse the progression of MMD. The current drug treatment for in MMD only targets its clinical symptoms, including ischemia and hemorrhage. The main choice of treatment for MMD is surgical revascularization. As an increasing number of hospitals have developed surgical treatment for MMD, our compiling group has jointly discussed the formulation of a consensus among Chinese experts on the treatment of MMD.

Bibliometric and visual analysis of cerebral revascularization from 1999 to 2022

Background

Cerebral revascularization is a neurosurgical procedure used to restore the cerebral collateral circulation channel. This study examines the countries, institutions, authors, journals, keywords, and references related to the disease in the field of cerebral revascularization from 1999 to 2022 from a bibliometrics perspective, evaluates the changes of knowledge structure clustering and identifies the new hot spots and new research directions in this field.

Methods

The Web of Science Core Collection (WOSCC) database and the PICOS retrieval method were used to conduct a comprehensive search for articles and reviews pertaining to cerebral revascularization. The final filtered data were bibliometrically and visually drawn using Microsoft office 365, CiteSpace (v.6.1.R2), and VOSviewer (v.1.6.18).

Results

From 1999 to 2022, a total of 854 articles pertaining to cerebral revascularization, which originated from 46 nations, 482 institutions, and 686 researchers, were extracted from the WOSCC database, and the number of publications in this field of study was rising. The United States held the highest proportion in the ranking analysis of countries, institutions, authors, and journals. By analyzing co-citations, the scientific organization of this field and the development status of frontier fields were realized. Cerebral revascularization, moyamoya disease, extracranial intracranial bypass, and occlusion are the current research focal points in the field of cerebral revascularization. Hyperperfusion and vascular disorder may also become a new study focus in this discipline in the near future.

Conclusion

Using the method of bibliometrics, this study analyzed and reviewed the articles in the field of cerebral revascularization, which enabled scholars to better comprehend the dynamic process in this field and provided a foundation for future in-depth research.

Transient neurological events in childhood moyamoya disease

OBJECTIVE

Patients sometimes experience transient neurological events (TNEs) during the early postoperative period after revascularization surgery for childhood moyamoya disease. The clinical background and pathophysiology of TNEs remain unclear. This study aimed to evaluate the incidence rate of TNEs and discuss the factors associated with pediatric moyamoya disease.

METHODS

The authors retrospectively reviewed 110 cerebral hemispheres of 61 pediatric patients younger than 15 years who were treated from 2011 to 2020. All children underwent either simple double-direct or combined revascularization surgery. Of these 61 patients, 52 underwent bilateral surgery and 9 underwent unilateral surgery. The authors calculated the incidence of TNEs in accordance with a previously reported TNE definition. Cerebral blood flow (CBF) was evaluated in all eligible cases with xenon CT immediately after revascularization surgery.

RESULTS

The incidence rate of TNEs in patients with childhood moyamoya disease was 26.4%. TNEs occurred after an average (range) of 6.26 (2-12) days postoperatively without triggers, and all identified TNEs spontaneously resolved within 2 weeks. The most common symptoms were dysarthria, facial palsy, and numbness around the mouth, followed by sensory disturbance of the upper extremities. The presence of focal hyperperfusion on xenon CT performed immediately after revascularization surgery was strongly correlated with the incidence of TNEs (p = 0.0001). Focal hyperperfusion was observed in 43 of 110 operative sides (39.1%). Notably, only 25.6% of patients with focal hyperperfusion showed numerical global hyperperfusion. In addition, a decrease in CBF compared with the thalamic region in the contralateral side was observed in TNE-affected cases (p = 0.0443).

CONCLUSIONS

TNEs occurred more frequently in childhood moyamoya disease patients than expected. The clinical background, including symptoms, timing, and duration, was almost identical to TNEs in adults. Focal hyperperfusion, rather than numerical global hyperperfusion, was strongly correlated with the incidence of TNEs. Furthermore, the authors advocate the notion that a clinical course where symptoms occur without triggers may be a unique characteristic of TNEs, especially in childhood moyamoya disease.

Effectiveness of pharmacologic interventions for prevention of cerebral hyperperfusion syndrome following bypass surgery

BACKGROUND

Cerebral hyperperfusion syndrome (CHS) following bypass surgery is a major cause of neurological morbidity and mortality. However, data regarding its prevention have not been assorted until date.

OBJECTIVE

The objective of this study was to review the literature and evaluate whether any conclusion can be drawn regarding the effectiveness of any measure on preventing bypass-related CHS.

METHODS

We systematically reviewed PubMed and Cochrane Library from September 2008 to September 2018 to collect data regarding the effectiveness of pharmacologic interventions on the refers to pretreatment (PRE) of bypass-related CHS. We categorized interventions regarding their class of drugs and their combinations and calculated overall pooled estimates of proportions of CHS development through random-effects meta-analysis of proportions.

RESULTS

Our search yielded 649 studies, of which 23 fulfilled inclusion criteria. Meta-analysis included 23 studies/2,041 cases. In Group A (blood pressure [BP] control), 202 out of 1,174 pretreated cases developed CHS (23.3% pooled estimate; 95% confidence interval [CI]: 9.9-39.4), Group B (BP control + free radical scavenger [FRS]) 10/263 (0.3%; 95% CI: 0.0-14.1), Group C (BP control + antiplatelet) 22/204 (10.3%; 95% CI: 5.1-16.7), and Group D (BP control + postoperative sedation) 29/400 (6.8%; 95% CI: 4.4-9.6)].

CONCLUSIONS

BP control alone has not been proven effective in preventing CHS. However, BP control along with either a FRS or an antiplatelet agent or postoperative sedation seems to reduce the incidence of CHS.

A flow self-regulating superficial temporal artery–middle cerebral artery bypass based on side-to-side anastomosis for adult patients with moyamoya disease

OBJECTIVE

Side-to-side (S-S) superficial temporal artery–middle cerebral artery (STA-MCA) bypass was reportedly used to treat a special moyamoya disease (MMD) patient with collaterals arising from the donor STA. However, the S-S technique is not routinely performed to date, and its benefits are still unknown for adult MMD. The purpose of this study was to investigate the possibility of routine use of the S-S technique for adult MMD.

METHODS

The authors retrospectively analyzed the clinical data of 50 adult patients (65 hemispheres, including 30 in the end-to-side [E-S] group and 35 in the S-S group) with MMD who underwent STA-MCA bypass. The patient demographic characteristics, clinical courses, technical details, intraoperative blood flow data, postoperative and preoperative relative cerebral blood flow (rCBF) values, modified Rankin Scale (mRS) scores, and short-term revascularization results were compared between the 2 groups.

RESULTS

There were no significant differences observed in terms of the baseline characteristics, bypass patency rates, postoperative/preoperative rCBF values, incidence of cerebral hyperperfusion syndrome (CHS), mRS scores, and short-term revascularization results between the 2 groups (all p > 0.05). Intraoperative blood flow analysis showed that the increase of STA flow in the E-S group was significantly higher than that of proximal STA flow in the S-S group (p = 0.008). Although the increases of proximal and distal recipient flow in the E-S group seemed greater than those in the S-S group, the results were not statistically significant (p = 0.086 for proximal flow and p = 0.076 for distal flow). CHS symptoms in the S-S group were milder and with much shorter duration. The follow-up angiographic data of the representative case demonstrated that both frontal and parietal STA branches and the occipital artery participated in postoperative collateralization.

CONCLUSIONS

S-S anastomosis can achieve comparable clinical effects to standard E-S construction. S-S anastomosis used in adult MMD demonstrated mild CHS symptoms with short duration and had the potential to arouse all scalp arteries as donor sources for revascularization through the intact distal STA branch via flow self-regulation.

Symptomatic hyperperfusion after combined revascularization surgery in patients with pediatric moyamoya disease: patient series

BACKGROUND

Symptomatic hyperperfusion after cerebral revascularization for pediatric moyamoya disease (MMD) is a rare phenomenon. The authors report a series of patients with this condition.

OBSERVATIONS

In all three patients in this case series, the combined revascularization was on the left side, the patency of bypass grafts was confirmed after surgery, and focal hyperemia around the anastomotic site was observed on single photon emission computed tomography (SPECT). On the first to eighth days after surgery, all of the patients developed neurological manifestations, including motor aphasia, cheiro-oral syndrome, motor weakness of their right upper limbs, and severe headaches. These symptoms disappeared completely approximately 2 weeks after surgery, and all patients were discharged from the hospital. Quantitative SPECT was performed to determine the proportional change in cerebral blood flow (ΔRCBF) (to ipsilateral cerebellar ratio (denoted ΔRCBF) in the region of interest around the anastomoses, and the mean value was 1.34 (range, 1.29–1.41).

LESSONS

This rare condition, which develops soon after surgery, requires an accurate diagnosis by SPECT. One indicator is that the ΔRCBF has risen to 1.3 or higher. Subsequently, strategic blood pressure treatment and fluid management could prevent the development of hemorrhagic stroke.

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.

Five-day bed rest reduces postoperative intracerebral hemorrhage after direct bypass for Moyamoya disease

OBJECTIVES

Postoperative intracerebral hemorrhage (ICH) after direct bypass surgery for Moyamoya disease (MMD) could contribute to neurological deterioration. The aim of this study was to evaluate the effectiveness of five-day bed rest in reducing the occurrence of postoperative ICH.

METHODS

This study included 122 consecutive hemispheres in 87 Japanese adult MMD patients, comprised of 80 control hemispheres from historical data and 42 hemispheres after five-day bed rest. They all underwent direct bypass surgery. The incidence of postoperative ICH and neurological deterioration assessed via the modified Rankin Scale (mRS) were investigated and statistically analyzed.

RESULTS

Postoperative ICH was observed in 9 out of the 80 (11.3%) control patients, but not in the 42 patients with five-day bed rest. The incidence of postoperative ICH and neurological deterioration via the mRS were significantly different between the two groups (p= 0.0268 and 0.0078, respectively). Univariate logistic analysis revealed that five-day bed rest significantly reduced the incidence of postoperative ICH (p= 0.0048).

CONCLUSIONS

Five-day bed rest after direct bypass surgery dramatically can reduce the incidence of postoperative ICH and neurological deterioration after direct bypass surgery.

Preventive Effect of Bypass Surgery on Rebleeding in Patients with Hemorrhagic Twiglike Middle Cerebral Artery

BACKGROUND

Aplastic or twiglike middle cerebral artery (Ap/T-MCA) is a rare cerebrovascular anomaly correlated to stroke. The most common characteristic of the disease is intracerebral hemorrhage. However, treatment measures that can prevent rebleeding have not yet been established.

OBJECTIVE

We sought to validate whether extracranial-intracranial (EC-IC) bypass is effective in preventing recurrent intracerebral hemorrhage in patients with Ap/T-MCA.

METHODS

Ap/T-MCA was defined on the basis of the following criteria: 1) M1 occlusion with plexiform vessels, 2) unilateral MCA involvement without progression to the contralateral side, 3) no significant stenosis in the M2 segment, and 4) no stenoocclusive lesions in other intracranial major arteries. The clinical features, surgical procedures, radiologic changes, and treatment outcomes of patients with Ap/T-MCA who presented with ipsilateral intracerebral hemorrhage at our institution from April 2004 to December 2019 were retrospectively reviewed.

RESULTS

Seven patients fulfilled the criteria for hemorrhagic Ap/T-MCA. Female preponderance was observed, and the mean age at the time of onset was 38 (range: 28-47) years. Three patients presented with pure intraventricular hemorrhage and 4 with intraparenchymal hemorrhage. Of the 4 patients, 2 had intraventricular extension. All patients underwent EC-IC bypass and did not present with stroke during the follow-up period (median: 36 [range: 5-140] months). Follow-up magnetic resonance imaging revealed regression of the twiglike vessels or periventricular choroidal anastomosis within 1 year after surgery in all patients.

CONCLUSIONS

EC-IC bypass may be a treatment option that can prevent rebleeding in patients with hemorrhagic Ap/T-MCA.

Postoperative stroke and neurological outcomes in the early phase after revascularization surgeries for moyamoya disease: an age-stratified comparative analysis

Stroke and neurological outcomes in the early phase following revascularization for moyamoya disease (MMD) may depend on the patient's age. In this study, an age-stratified comparative analysis was performed to clarify this issue. We reviewed 105 MMD patients who underwent 179 revascularization surgeries. The demographic characteristics were collected in four age groups (≤ 5 and 6-17 years for pediatric patients and 18-49 and ≥ 50 years for adults). Additionally, we assessed the incidence of subsequent stroke and deterioration of modified Rankin Scale (mRS) score. Then, we evaluated predictors of postoperative stroke and mRS deterioration using logistic regression. The mean patient age was 26.2 ± 18.5 years. No significant difference in the incidence of postoperative stroke was observed between age groups; however, the incidence tended to be increased among patients aged ≤ 5 years (17.9%) and patients aged ≥ 50 years (16.7%). Deterioration of mRS scores was significantly associated with ages ≤ 5 years (17.9%) and ≥ 50 years (11.1%). Logistic regression showed that posterior cerebral artery involvement (odds ratio [OR], 4.6) and postoperative transient neurological events (TNEs) (OR, 5.93) were risk factors for postoperative stroke. Age ≤ 5 years (OR, 9.73), postoperative TNEs (OR, 7.38), and postoperative stroke (OR, 49) were identified as predictors of unfavorable neurological outcomes. The novel feature of this comparative analysis by age group is that membership in the early-childhood MMD patient group (under 5 years old) was an independent risk factor for unfavorable short-term neurological outcomes and was mainly associated with the incidence of postoperative severe cerebral infarction.

[Ischemic complications following surgical treatment of moyamoya disease: risk factors and prevention]

BACKGROUND

One of the most difficult problems in surgical treatment of moyamoya disease is prevention of ischemic perioperative complications. The risk of these events is significantly higher compared to other cerebrovascular diseases (up to 30%).

OBJECTIVE

To identify unfavorable prognostic factors of perioperative cerebral ischemic complications, to determine the group of high-risk patients and to develop the guidelines for perioperative management of these patients.

MATERIAL AND METHODS

We analyzed clinical and diagnostic data and postoperative outcomes in 80 patients with various forms of moyamoya disease. These patients underwent 134 different interventions. Staged revascularization of both hemispheres was performed in 40 patients (80 surgeries). Most patients (n = 55) underwent combined brain revascularization (79 surgeries).

RESULTS

Persistent postoperative complications (ischemic stroke) developed in 7 cases (5.3%). Transient neurological impairment was observed in 36 cases (27%). Statistical analysis revealed the following risk factors of perioperative complications: critical stenosis/occlusion of posterior cerebral artery (OR 9.704), severe perfusion deficit (OR 5.393) and previous TIA or ischemic stroke within 3 months prior to surgery (OR 6.433). If at least two of these signs are present, sensitivity of prognosis for postoperative complications is 80.7% and 88.6%, respectively.

CONCLUSION

Patients with moyamoya disease are at high risk of perioperative complications due to complex rearrangement of collateral cerebral circulation and high sensitivity of brain to local and systemic hemodynamic changes. Patients with risk factors require careful perioperative management to exclude pathogenetic factors provoking ischemia. Early surgical treatment is advisable to reduce the risk of ischemic and hemorrhagic lesions following natural course of disease and severe perioperative complications.

Hemodynamic analysis of the recipient parasylvian cortical arteries for predicting postoperative hyperperfusion during STA-MCA bypass in adult patients with moyamoya disease

OBJECTIVE

Superficial temporal artery-middle cerebral artery (STA-MCA) bypass is a common approach for treating moyamoya disease (MMD); however, the selection of recipient vessels is still controversial, and its relationship with postoperative cerebral hyperperfusion (CHP) has not been revealed. The aim of the study was to investigate the relationship between the hemodynamic sources of the recipient parasylvian cortical arteries (PSCAs) and the occurrence of postoperative CHP.

METHODS

The authors retrospectively analyzed the clinical data from 68 adult patients (75 hemispheres) with MMD who underwent STA-MCA bypass. Based on their hemodynamic sources from the MCA and non-MCAs, the PSCAs were classified as M-PSCAs and non-M-PSCAs, and their distributional characteristics were studied. Moreover, the patients' demographics, incidence of postoperative CHP, and post- and preoperative relative cerebral blood flow values were examined.

RESULTS

The digital subtraction angiography analysis demonstrated that 40% (30/75) of the recipient PSCAs had no hemodynamic relationship with the MCA. The post- and preoperative relative cerebral blood flow values of the M-PSCA group were significantly higher than those of the non-M-PSCA group (p < 0.001). Multivariate analysis revealed that the hemodynamic source of PSCAs from the MCA was significantly associated with the development of focal (p = 0.003) and symptomatic (p = 0.021) CHP. Twelve (85.7%) of the 14 patients with symptomatic CHP and all 4 (100%) patients with postoperative hemorrhage were from the M-PSCA group.

CONCLUSIONS

This study revealed that direct anastomoses of PSCAs with anterograde hemodynamic sources from the MCA had a high risk of postoperative CHP during STA-MCA bypass in adult patients with MMD.

Intraoperative local hemodynamic quantitative analysis of direct revascularization in patients with moyamoya disease

Direct bypass surgery improves blood flow in patients with moyamoya disease (MMD) as well as causes local flow relocation and disturbance. This study aimed to describe the characteristics and changes of quantitative blood flow in MMD patients. Sixty-four consecutive MMD patients (67 hemispheres) who underwent STA-MCA anastomosis between August 2013 and September 2017 were included in this study. Intraoperative blood flow of superficial temporal artery and middle cerebral artery was measured with a noninvasive, ultrasound flowprobe, before and after the bypass. All data were collected prospectively. Before the bypass, 67 hemispheres were measured and 45 hemispheres acquired post-bypass measurements. Thirty-three (49.3%) had anterograde flow and 34 (50.7%) had retrograde. Retrograde blood flow was significantly higher than anterograde blood flow in MCA-M4 section (3.71 ± 2.78 ml/min vs 2.39 ± 1.71 ml/min, P = 0.023). Thirty-eight (56.7%) patients had local cerebrovascular reactivity, whereas 29 (43.3%) lost it. After bypass, blood flow was changed into three patterns: anterograde flow (1, 2.2%), retrograde flow (3, 6.7%), and bi-direction flow (41, 91.1%). Flow of M4 was significantly improved in both proximal (13.64 ± 9.16 vs 3.28 ± 2.57, P < 0.001) and distal (7.17 ± 7.21 vs 3.28 ± 2.57, P = 0.002) sides to the bypass. Postoperative infarctions occurred in 4 (8.9%) patients. All postoperative infarctions (n = 4) happened in those patients who did not have change of flow direction in M4 section distal to the bypass (P = 0.040). Direct bypass surgery improves local blood flow after bypass surgery in both sides of the anastomosis. Flow direction was usually changed after the surgery into a bi-direction pattern: anterograde flow in M4 distal to the bypass, and retrograde flow in M4 proximal to the bypass. Proximal side acquired around 5.4 times of flow than the distal side. Patients with change of flow direction in distal M4 were related with lower risks of postoperative infarctions.

Flow-augmentation bypass for moyamoya disease

Moyamoya disease (MMD) is a chronic, occlusive cerebrovascular disease with unknown etiology, which is characterized by progressive steno-occlusive changes at the terminal portion of the internal carotid artery and an abnormal vascular network formation at the base of the brain. MMD has an intrinsic temporal nature to attempt a gradual conversion of the vascular supply for the brain from intracranial/internal carotid (IC) system to extracranial/external carotid (EC) system, so called "IC-EC conversion." Compatible cerebrovascular angio-architecture could be found in association with a variety of conditions such as neuro-fibromatosis type-1, Down's syndrome and cranial irradiation, which is called as moyamoya syndrome, akin/quasi MMD, or secondary MMD. Diagnosis of moyamoya vasculopathy, either idiopathic or secondary, is clinically important because flow-augmentation bypass is markedly beneficial for this entity to prevent cerebral ischemic attack by improving cerebral blood flow. Moreover, recent evidence indicated that flow-augmentation bypass could prevent re-bleeding in hemorrhagic MMD patients. Based on these backgrounds, there is a worldwide increase in the number of MMD patients undergoing bypass surgery. We sought to demonstrate our standard surgical procedure of superficial temporal artery-middle cerebral artery bypass with indirect pial synangiosis for MMD and its technical pitfall. We also discuss the intrinsic peri-operative hemodynamics of MMD after bypass surgery, including local cerebral hyper-perfusion and characteristic hemodynamic ischemia caused by watershed shift phenomenon. The aim of this review article is to understand the basic pathology of MMD, which is essential for complication avoidance while conducting flow-augmentation bypass for MMD.

Individualized Perioperative Blood Pressure Management for Adult Moyamoya Disease: Experience from 186 Consecutive Procedures

BACKGROUND

In adult patients with moyamoya disease (MMD) underwent combined revascularization, cerebral infarction during the acute postoperative phase is common and can lead to neurological dysfunction after revascularization in MMD patients. The aim of this study was to share the experience of individualized perioperative blood pressure (BP) management for adult MMD patients in one single center.

METHODS

We retrospectively reviewed 144 adult patients with MMD who underwent 186 procedures of combined revascularization at our institution from March 2013 to July 2019. Clinical features and outcomes were analyzed, in particular regarding cerebral infarction and hyperperfusion syndrome (HPS). All of the patients received individualized management perioperatively, especially about the blood pressure management according to the characteristics of moyamoya disease.

RESULTS

Postoperative cerebral infarction and HPS within 14 days after revascularization were recorded. Cerebral infarction occurred in four (2.1%) procedures among four patients. No patients suffered from a malignant cerebral infarction and only one patient had permanent neurological deficits. The incidence of HPS was 10.8% and no one presented with intracranial hemorrhage. All of the symptoms were reversible without any brain parenchymal injury.

CONCLUSIONS

Our findings suggest that we can decrease the incidence and extent of cerebral infarction in adult MMD patients following combined revascularization by individualized perioperative BP management.

Preoperative platelet count may predict postoperative symptomatic cerebral hyperperfusion syndrome after superficial temporal artery-middle cerebral artery anastomosis in moyamoya patients

OBJECTIVE

Platelets play a critical role in the inflammatory response, accompanied by microvascular endothelial dysfunction, underlying postoperative symptomatic cerebral hyperperfusion syndrome (PSCHS) after superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis in moyamoya patients. We examined whether the preoperative platelet count can predict PSCHS after STA-MCA anastomosis in such patients.

METHODS

In 160 adult moyamoya patients undergoing 186 STA-MCA anastomoses, preoperative (demographics, initial clinical manifestation, and Suzuki grade), intraoperative (surgical time, operative side, fluid balance, and maximum and minimum mean blood pressure before and after vessel anastomosis), immediate postoperative (APACHE 2 score), and laboratory (hemoglobin and C-reactive protein levels and white blood cell and platelet counts) data were collected retrospectively.

RESULTS

84 patients (90 sides, 48.4 %) developed PSCHS with a median(IQR) onset of postoperative day 1(0-3) and duration of 4(3-7) days. The preoperative (25.2[22.8-28.0] vs. 23.1[19.7-26.2] ×10⁴/μL, p = 0.009) platelet count was significantly higher in patients with PSCHS than in those without. The preoperative platelet count (odds ratio[95 % confidence interval], 1.14[1.03-1.27], p = 0.011), operation on the dominant hemisphere (6.84 [3.26-14.36], p < 0.001), and negative fluid balance (2.41[1.04-5.59], p = 0.040) were significant independent predictors of PSCHS. The optimal cut-off value for preoperative platelet count was 22.7 ×10⁴/μL, and PSCHS developed more frequently in cases with a preoperative platelet count ≥ 22.7 × 10⁴/μL (2.90[1.54-5.45]; p = 0.001).

CONCLUSION

A high preoperative platelet count may be associated with the development of PSCHS after STA-MCA anastomosis in adult moyamoya patients.

Decreased cortical perfusion in areas with blood-brain barrier dysfunction in Moyamoya disease

BACKGROUND

Recently, several studies have focused on the relationship between blood-brain barrier (BBB) impairment and the etiology of Moyamoya disease (MMD). However, in vivo studies investigating about BBB impairment and cortical perfusion in MMD patients were really rare.

METHODS

This study included 16 patients diagnosed with MMD and 9 patients with atherosclerotic cerebrovascular disease (ACVD); all of who were treated with superficial temporal artery-middle cerebral artery (STA-MCA) bypass. Cortical perfusion was assessed using intraoperative indocyanine green (ICG) videoangiography by calculating the blood flow index (BFI). In addition, we used sodium fluorescein (NaFl) to evaluate the permeability of BBB in vivo during operation.

RESULTS

The results showed that BBB impairment in MMD patients was more significant than that in ACVD patients, whereas, the cortical perfusion was comparable between two groups. BFI was significantly improved after STA-MCA bypass both in the MMD group (post-operation vs pre-operation: 109.2 ± 67.7 vs 64.3 ± 35.0, p = 0.004) and the ACVD group (post-operation vs pre-operation: 137.6 ± 89.6 vs 90.8 ± 58.3, p = 0.015). Moreover, BFI was significantly decreased in the cortex with BBB impairment as compared with that in the cortex with intact BBB (impaired BBB vs intact BBB: 55.7 ± 26.5 vs 87.6 ± 55.1, p = 0.025). Following bypass, the cortical perfusion significantly improved in the area of BBB impairment (post-operation vs pre-operation: 93.8 ± 75.2 vs 55.7 ± 26.5, p = 0.004), which was not observed in the BBB intact area (post-operation vs pre-operation: 92.4 ± 50.4 vs 87.6 ± 55.1, p = 0.58).

CONCLUSION

In summary, we observed that BBB impairment in MMD patients was more significant than that in ACVD patients. This study also demonstrated for the first time that cortical perfusion was significantly decreased in the cortex with BBB impairment as compared with that in the cortex with intact BBB in MMD patients. We also observed that After STA-MCA bypass, the cortical perfusion was significantly improved in the cortex with BBB impairment. These results may provide a new insight for BBB impairment and cortical perfusion in the etiology of MMD.

Pre-operative higher hematocrit and lower total protein levels are independent risk factors for cerebral hyperperfusion syndrome after superficial temporal artery-middle cerebral artery anastomosis with pial synangiosis in adult moyamoya disease patients-case-control study

Superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis is a standard treatment for adult moyamoya disease (MMD) patients. Cerebral hyperperfusion (CHP) syndrome is one of the most serious complications of this procedure that can result in deleterious outcomes, but predicting CHP before revascularization surgery remains challenging. Furthermore, the hematological/serological factors associated with CHP syndrome are unknown. To investigate the correlation between pre-operative hematological/serological factors and the development of CHP syndrome after STA-MCA anastomosis with encephalo-duro-myo-synangiosis (EDMS) for MMD., a pre-operative peripheral blood test was performed within 5 days before surgery. Local cerebral blood flow (CBF) at the site of anastomosis was quantified by N-isopropyl-p-[¹²³I] iodoamphetamine single-photon emission computed tomography 1 and 7 days after surgery, and the pre-operative CBF value at the corresponding area was measured. We defined CHP syndrome as a local CBF increase over 150% compared with the pre-operative value, which was responsible for delayed intracranial hemorrhage, transient focal neurological deterioration, and/or seizure. Then, we retrospectively investigated the correlation between peripheral blood test results and the development of CHP syndrome. CHP syndrome 1 day after STA-MCA anastomosis with EDMS was observed in nine patients (9/114 hemispheres; 7.9%). Multivariate analysis with multiple imputation revealed that higher hematocrit value and lower total protein level were significantly associated with the development of CHP syndrome (p value: 0.028 and 0.043, respectively). Higher pre-operative hematocrit levels and lower pre-operative total protein levels are novel risk factors for CHP syndrome after direct revascularization surgery in adult MMD patients.

Severe cerebral edema induced by watershed shift after bypass in a patient with chronic steno-occlusive disease: a case report and short literature review

Background

Carotid occlusive disease is a type of progressive disease resulting in ischemic stroke. Extracranial-intracranial bypass surgery represents a valid therapeutic option when medical treatment does not make effects. The appearance of cerebral edema following bypass is common during acute stage. Additionally, there are many causes of mild cerebral edema, such as hemodynamic changes, venous congestion and others. However, severe edema involving large brain tissue, which presents as reversible aphasia and hemiplegia, remains to be elucidated.

Case presentation

A 55-year-old man was admitted to the neurosurgery department for repeated dizziness for over a year and sudden onset of syncope 1 month prior, and he was diagnosed with carotid occlusive disease. After surgical contraindications were excluded, dual bypass and encephalo-duro-myo-synangiosis were performed. Although blood pressure and fluid management were strictly under control promptly after surgery, massive cerebral edema involving the left anterior cerebral artery and middle cerebral artery territories occurred from the 6th day after surgery. Additionally, no discernible cerebral infarction or hemorrhage occurred. Moreover, the cerebral blood flow of the middle cerebral artery displayed an early decrease followed by delayed elevation on the left side. Without restricting the spreading of cerebral edema, life-threatening cerebral herniation could develop at any time. Mannitol and furosemide were administered for impending cerebral herniation. The amelioration of symptoms was noticed on the 16th day after surgery. The patient felt relief on the 21st day after surgery. Digital subtraction angiography performed on the 180th day after surgery demonstrated the patency of dual anastomosed vessels, and the patient recovered without any permanent neurological deficit.

Conclusion

Based on changes in cerebral blood flow and reversible symptoms, the “watershed shift” phenomenon could explain such a severe deficit. However, this deficit was not the same as the classical presentation of the “watershed shift”, which involves a moderate amount of brain tissue and presents significant increases in cerebral blood flow. In addition to the “watershed shift”, a swollen temporal muscle may also participate in the progression of focal edema.

Prediction of Cerebral Hyperperfusion after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis by Three-Dimensional-Time-of-Flight Magnetic Resonance Angiography in Adult Patients with Moyamoya Disease

Introduction: Superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis is an effective surgical procedure for adult patients with moyamoya disease (MMD) and is known to have the potential to prevent cerebral ischemia and/or hemorrhagic stroke. Cerebral hyperperfusion (CHP) syndrome is one of the serious complications of this procedure that can result in deleterious outcomes, such as delayed intracerebral hemorrhage, but the prediction of CHP before revascularization surgery remains challenging. The present study evaluated the diagnostic value of preoperative three-dimensional (3D)-time-of-flight (TOF) magnetic resonance angiography (MRA) for predicting CHP after STA-MCA anastomosis for MMD. Materials and Methods: The signal intensity of the peripheral portion of the intracranial major arteries, such as the anterior cerebral artery (ACA), MCA, and posterior cerebral artery (PCA) ipsilateral to STA-MCA anastomosis, on preoperative MRA was graded (0–2 in each vessel) according to the ability to visualize each vessel on 97 affected hemispheres in 83 adult MMD patients. Local cerebral blood flow (CBF) at the site of anastomosis was quantitatively measured by N-isopropyl-p-[123I]-iodoamphetamine single-photon emission computed tomography 1 and 7 days after surgery, in addition to the preoperative CBF value at the corresponding area. Then, we investigated the correlation between the preoperative MRA score and the development of CHP. Results: The CHP phenomenon 1 day after STA-MCA anastomosis (local CBF increase over 150% compared with the preoperative value) was evident in 27 patients (27/97 hemispheres; 28%). Among them, 8 (8 hemispheres) developed CHP syndrome. Multivariate analysis revealed that the hemispheric MRA score (0–6), the summed ACA, MCA, and PCA scores for the affected hemisphere, was significantly associated with the development of CHP syndrome (p = 0.011). The hemispheric MRA score was also significantly correlated with the CHP phenomenon, either symptomatic or asymptomatic (p < 0.001). Conclusion: The signal intensity of the intracranial major arteries, including the ACA, MCA, and PCA, on preoperative 3D-TOF MRA may identify adult MMD patients at higher risk for CHP after direct revascularization surgery.

Matching Selection of Donor-Recipient Vessels in Revascularization Surgery Effectively Reduce the Incidence of Postoperative Hyperperfusion Syndrome in Adult Moyamoya Disease: A Retrospective Comparison Study

INTRODUCTION

Cerebral hyperperfusion syndrome (CHS) is one of the most serious complications after revascularization surgery in patients with moyamoya disease (MMD). However, there are few effective measures to prevent the occurrence of CHS.

OBJECTIVE

The present study aims to examine the effect of the method about matching selection of donor-recipient vessels during revascularization surgery on the incidence of postoperative CHS in adult MMD patients.

METHODS

216 Chinese adult patients with MMD received surgery treatment between January 2018 and December 2019 in our hospital were enrolled in this study. 191 out of 216 patients were included in this study. Matching selection method was defined as follows: (1) blood flow: the direction of blood flow and speed of the donor artery and potential receptor arteries were measured by flow 800 indocyanine green video angiography; (2) vascular diameter: the diameters of the donor artery and potential receptor arteries by a miniature ruler. Only the artery with antegrade flow and with smallest difference in flow speed and diameter with the donor artery will be selected as the receptor artery to perform anastomosis. Matching selection was performed from January 2019. Digital subtraction angiography was performed in all patients for initial MMD diagnosis. Perioperative cerebral perfusion and related clinical symptoms were monitored. Clinical characteristics, contralateral progression, and risk factors were reviewed. The incidence of CHS and the correlation of CHS with baseline characteristics or clinical conditions were analyzed.

RESULTS

Of these 191 patients, 82 patients received matching selection of donor-recipient vessels during revascularization surgery and 109 patients without. The postoperative CHS incidence in the matching group was 3.66%, which was much lower than that in the nonmatching group (15.60%). Multivariate analysis did not reveal a significant risk factor between the progression group and the nonprogression group. Correlation analysis revealed only the matching selection method was significantly associated with the reduced postoperative CHS incidence in MMD patients.

CONCLUSIONS

The matching selection of donor-recipient vessels during revascularization surgery effectively reduces the incidence of postoperative CHS in adult patients with MMD.

Crossed cerebellar diaschisis as an indicator of severe cerebral hyperperfusion after direct bypass for moyamoya disease

Cerebral hyperperfusion (HP) complicates the postoperative course of patients with moyamoya disease (MMD) after direct revascularization surgery. Crossed cerebellar diaschisis (CCD) has been considered to be rarely associated with HP after revascularization surgery. This study aimed to describe the clinical features and factors associated with CCD secondary to cerebral HP after revascularization surgery for MMD. We analyzed 150 consecutive hemispheres including 101 in adults and 49 in pediatric patients who underwent combined direct and indirect bypass for MMD. Using single-photon emission computed tomography (SPECT), serial cerebral blood flow (CBF) was measured immediately after the surgery and on postoperative days 2 and 7. Pre- and postoperative voxel-based analysis of SPECT findings was performed to compare the changes in regional CBF. Multivariate logistic regression analysis was performed to test the effect of multiple variables on CCD. Asymptomatic and symptomatic HP was observed in 41.3% (62/150) and 16.7% (25/150) of the operated hemispheres, respectively. CCD was observed in 18.4% (16/87) of these hemispheres with radiological HP. Multivariate analysis revealed that the occurrence of CCD was significantly associated with symptomatic HP (p = 0.0015). Voxel-based analysis showed that the CBF increase in the operated frontal cortex, and the CBF reduction in the contralateral cerebellar hemisphere on day 7 were significantly larger in symptomatic HP than in asymptomatic HP (median 11.3% vs 7.5%; - 6.0% vs - 1.7%, respectively). CCD secondary to postoperative HP is more common than anticipated in MMD. CCD could potentially be used as an indicator of severe postoperative HP in patients with MMD.

dl-3-n-butylphthalide for alleviation of neurological deficit after combined extracranial-intracranial revascularization for moyamoya disease: a propensity score-matched analysis

OBJECTIVE

Postoperative neurological deficits impair the overall outcome of revascularization surgery for patients with moyamoya disease (MMD). dl-3-n-butylphthalide (NBP) is approved for the treatment of ischemic stroke in China. This pilot study evaluated the effect of NBP on perioperative stroke and neurological deficits in patients with MMD.

METHODS

The authors studied cases in which patients underwent combined revascularization surgery for MMD at their institution, with or without NBP administration. The overall study group included 164 patients (213 surgically treated hemispheres), including 49 patients who received NBP (25 mg twice daily) for 7 postoperative days. The incidence of perioperative stroke and transient neurological deficit (TND) and the severity of neurological deficits were compared between 49 propensity score-matched case pairs with or without NBP treatment. Subgroup analyses by type of onset and preoperative neurological status were also performed to determine specific characteristics of patients who might benefit from NBP administration.

RESULTS

In the overall cohort, baseline characteristics differed with respect to preoperative stroke and modified Rankin Scale (mRS) score between patients who received NBP and those who did not receive it. In the 49 propensity score-matched pairs, postoperative stroke was observed in 11 patients and TND occurred in 21 patients, with no significant difference in incidence between the 2 groups. However, the TND was less severe in the NBP-treated group (p = 0.01). At 1 month after surgery, the neurological outcome was more favorable (p = 0.001) and the disability-free recovery rate was higher in patients with NBP treatment (p < 0.001). The number of patients who experienced an improved neurological function, compared to preoperative function, as measured by mRS, was greater in the NBP group than in the no-NBP group (p < 0.001). Multivariable analysis revealed that NBP administration was associated with decreased severity of TND (OR 0.28, p = 0.02), improved neurological function (OR 65.29, p = 0.04), and lower postoperative mRS score (OR 0.06, p < 0.001). These beneficial effects of NBP remained significant in ischemic type MMD and patients with preoperative mRS scores of 2 or greater.

CONCLUSIONS

Postoperative administration of NBP may alleviate perioperative neurological deficits after revascularization surgery for MMD, especially in patients with ischemic MMD and unfavorable preoperative status. The results of this study suggest that randomized controlled trials to assess the potential benefit of NBP in patients with MMD may be warranted.

Cerebral Hyperperfusion Syndrome After Revascularization Surgery in Patients with Moyamoya Disease: Systematic Review and Meta-Analysis

BACKGROUND

Cerebral hyperperfusion syndrome (CHS) after bypass surgery is known as a complication of moyamoya disease (MMD). However, the incidence of CHS has not been accurately reported, and there is no consensus on related risk factors.

OBJECTIVE

To evaluate the incidence and characteristics of CHS in patients with MMD after revascularization surgery via meta-analysis.

METHODS

Relevant cohort studies were retrieved through a literature search of PubMed, Embase, and Ovid until December 1, 2018. Eligible studies were identified per search criteria. A systematic review and meta-analysis were used to assess the CHS total incidence, incidence in pediatric patients with MMD and adult patients with MMD, incidence for direct and combined bypass surgery, progress rate, and proportion of each symptom (including transient neurologic deficits [TNDs], hemorrhage, and seizure).

RESULTS

A total of 27 cohort studies with 2225 patients were included in this meta-analysis. The weighted proportions per random-effects model were 16.5% (range, 11.3%-22.3%) for CHS total incidence, 3.8% (range, 0.3%-9.6%) for pediatric patients with MMD, 19.9% (range, 11.7%-29.4%) for adult patients with MMD, 15.4% (range, 5.4%-28.8%) for direct bypass surgery, and 15.2% (range, 8.4%-23.2%) for combined bypass surgery. Progress rate was 39.5% (range, 28.7%-50.8%). The most common CHS-related symptom was TNDs (70.2%; range, 56.3%-82.7%), followed by hemorrhage (15.0%; range, 5.5%-26.9%) and seizure (5.3%; range, 0.6%-12.9%).

CONCLUSIONS

CHS is a common complication after revascularization surgery in MMD. It is more frequently seen in adult patients. The most common CHS-related symptom was TNDs, followed by hemorrhage and seizure.

Intraoperative evaluation of local cerebral hemodynamic change by indocyanine green videoangiography: prediction of incidence and duration of postoperative transient neurological events in patients with moyamoya disease

OBJECTIVE

Transient neurological events (TNEs) occur frequently in the acute phase after direct bypass surgery for moyamoya disease (MMD), but there is currently no way to predict them. FlowInsight is a specialized software for analyzing indocyanine green (ICG) videoangiography taken with a surgical microscope. The purpose of this study was to investigate whether intraoperative evaluation of local hemodynamic changes around anastomotic sites using FlowInsight could predict the incidence and duration of TNEs.

METHODS

From patients who were diagnosed with MMD in our hospital between August 2014 and March 2017 and who underwent superficial temporal artery-middle cerebral artery bypass surgery, we investigated 25 hemispheres (in 22 patients) in which intraoperative ICG analysis was performed using FlowInsight. To evaluate the local cerebral hemodynamics before and after anastomosis, regions of interest were set at 3 locations on the brain surface around the anastomotic site, and the mean cerebral blood flow (CBF), mean gradation (Grad), mean transit time (MTT), and mean time to peak (TTP) were calculated from the 3 regions of interest. Furthermore, the change rate in CBF (ΔCBF [%]) was calculated using the formula (postanastomosis mean CBF - preanastomosis mean CBF)/preanastomosis mean CBF. ΔGrad (%), ΔMTT (%), and ΔTTP (%) were similarly calculated.

RESULTS

Postoperative stroke without TNE occurred in 2 of the 25 hemispheres. These 2 hemispheres (in 2 patients) were excluded from the study, and data from the remaining 23 hemispheres (in 20 patients) were analyzed. For each parameter (ΔCBF, ΔGrad, ΔMTT, and ΔTTP) calculated by FlowInsight, the difference between the groups with and without TNEs was significant. The median values for ΔCBF and ΔGrad were significantly higher in the TNE group than in the no-TNE group (ΔCBF 30.13 vs 3.54, p = 0.0106; ΔGrad 62.05 vs 10.78, p = 0.00435), whereas the median values for ΔMTT and ΔTTP were significantly lower in the TNE group (ΔMTT -16.90 vs -7.393, p = 0.023; ΔTTP -29.07 vs -7.02, p = 0.00342). Comparison of the area under the curve (AUC) for each parameter showed that ΔTTP had the highest AUC and was the parameter with the highest diagnostic accuracy (AUC 0.857). The Youden index revealed that the optimal cutoff value of ΔTTP was -11.61 (sensitivity 77.8%, specificity 71.4%) as a predictor of TNEs. In addition, Spearman's rank correlation coefficients were calculated, and ΔCBF, ΔGrad, ΔMTT, and ΔTTP each showed a strong correlation with the duration of TNEs. The larger the change in each parameter, the longer the TNEs persisted.

CONCLUSIONS

Intraoperative ICG videoangiography findings were correlated with the occurrence and duration of TNEs after direct bypass surgery for MMD. Screening for cases at high risk of TNEs can be achieved by ICG analysis using FlowInsight.

Multimodal neuronavigation-guided precision bypass in adult ischaemic patients with moyamoya disease: study protocol for a randomised controlled trial

INTRODUCTION

Revascularisation surgery is an important treatment of moyamoya disease (MMD). Several general methods of revascularisation had been used: direct, indirect and combined techniques. However, there had been no reports about the criteria of recipient arteries selection in bypass surgery for MMD. Surgeons usually choose the recipient arteries by their own experiences. Their choices of the recipient arteries are various and may contribute the different outcome of patients. The purpose is to identify utility and efficacy of precision bypass guided by multimodal neuronavigation of MMD in a prospective randomised controlled trial.

METHOD AND ANALYSIS

This study is a prospective randomised controlled clinical trial. This study will enrol a total of 100 eligible patients. These eligible patients will be randomised to the empirical bypass group and the multimodal neuronavigation-guided precision bypass group in a 1:1 ratio. Patient baseline characteristics and MMD characteristics will be described. In the multimodal neuronavigation-guided group, the blood velocity and blood flow of the recipient arteries will be identified. Surgical complications and outcomes at pretreatment, post-treatment, at discharge and at 3 month, 6 month, 12 month and end of trial will be analysed with CT perfusion, MRI, digital subtraction angiography, modified Rankin Scale, National Institute of Health Stroke Scale and modified Barthel Scale. This trial will determine whether multimodal neuronavigation-guided precision bypass is superior to empirical bypass in patients with MMD and identify the safety and efficacy of multimodal neuronavigation-guided precision bypass.

ETHICS AND DISSEMINATION

The study protocol and written informed consent were reviewed and approved by the Clinical Research Ethics Committee of Peking University International Hospital. Study findings will be disseminated in the printed media. The study started in August, 2018 and expected to be completed in December, 2020.

TRIAL REGISTRATION NUMBER

NCT03516851; Pre-results.

Efficacy of superficial temporal artery-middle cerebral artery double bypass in patients with hemorrhagic moyamoya disease: surgical effects for operated hemispheric sides

The effects of superficial temporal artery to middle cerebral artery (STA-MCA) double bypass on recurrent hemorrhage in the operated hemisphere in hemorrhagic moyamoya disease (HMD) have not been clearly demonstrated. This study evaluated the effectiveness of STA-MCA double bypass in the prevention of further hemorrhagic or ischemic events in the operated hemispheric sides in comparison to the conservatively treated non-operated sides. We retrospectively analyzed 52 hemispheres of 36 patients with adult-onset HMD treated with STA-MCA double bypass. Twenty and 16 patients underwent unilateral (unilateral group) and bilateral (bilateral group) surgery, respectively. In addition, the perioperative and long-term outcomes of the 52 operated sides and 20 non-operated sides in the unilateral group were compared. All bypass surgeries were successful, but 21% of the operated sides showed hyperperfusion as estimated by our methods. Perioperative mortality and morbidity rate were 0% and 5.6%, respectively. Concerning long-term follow-up, the annual rebleeding rate (ARR) in the unilateral and bilateral group was 2.7% and 2.6%/person-year, respectively (p = 0.256). The ARR in the operated and non-operated sides was 1.1% and 1.8%/side-year, respectively (p = 0.163). Two of 20 non-operated sides suffered from ischemic infarction during the follow-up period, while none of the 52 operated sides experienced ischemic events (p < 0.05). Although the long-term rebleeding rate in the operated hemisphere tended to be lower after STA-MCA double bypass compared with that in the non-operated hemisphere, the difference was not statistically significant. In conclusion, while STA-MCA double bypass could not clearly prevent rebleeding, it can prevent further ischemic attacks in patients with HMD.

Hemorrhagic Moyamoya Disease : A Recent Update

Moyamoya disease (MMD) is a progressive cerebrovascular disease with unknown etiology, characterized by bilateral stenoocclusive changes at the terminal portion of the internal carotid artery and an abnormal vascular network formation at the base of the brain. MMD has an intrinsic nature to convert the vascular supply for the brain from internal carotid (IC) system to the external carotid (EC) system, as indicated by Suzuki’s angiographic staging. Insufficiency of this ‘IC-EC conversion system’ could result not only in cerebral ischemia, but also in intracranial hemorrhage from inadequate collateral anastomosis, both of which represent the clinical manifestation of MMD. Surgical revascularization prevents cerebral ischemic attack by improving cerebral blood flow, and recent evidence further suggests that extracranial-intracranial bypass could powerfully reduce the risk of re-bleeding in MMD patients with posterior hemorrhage, who were known to have extremely high re-bleeding risk. Although the exact mechanism underlying the hemorrhagic presentation in MMD is undetermined, most recent angiographic analysis revealed the characteristic angio-architecture related to high re-bleeding risk, such as the extension and dilatation of choroidal collaterals and posterior cerebral artery involvement. We sought to update the current management strategy for hemorrhagic MMD, including the outcome of surgical revascularization for hemorrhagic MMD in our institute. Further investigations will clarify the optimal surgical strategy to prevent hemorrhagic manifestation in patients with MMD.

Long-Lasting Symptomatic Cerebral Hyperperfusion Syndrome following Superficial Temporal Artery-Middle Cerebral Artery Bypass in a Patient with Stenosis of Middle Cerebral Artery

Cerebral hyperperfusion syndrome (CHPS) is a complication that can occur after cerebral revascularization surgeries such as superficial temporal artery- (STA-) middle cerebral artery (MCA) anastomosis, and it can lead to neurological deteriorations. CHPS is usually temporary and disappears within two weeks. The authors present a case in which speech disturbance due to CHPS lasted unexpectedly long and three months was taken for full recovery. A 40-year-old woman, with a history of medication of quetiapine, dopamine 2 receptor antagonist as an antipsychotics for depression, underwent STA-MCA anastomosis for symptomatic left MCA stenosis. On the second day after surgery, the patient exhibited mild speech disturbance which deteriorated into complete motor aphasia and persisted for one month. SPECT showed the increase of cerebral blood flow (CBF) in left cerebrum, verifying the diagnosis of CHPS. Although CBF increase disappeared one month after surgery, speech disturbance continued for additionally two months with a slow improvement. This case represents a rare clinical course of CHPS. The presumable mechanisms of the prolongation of CHPS are discussed, and the medication of quetiapine might be one possible cause by its effect on cerebral vessels as dopamine 2 receptor antagonist, posing the caution against antipsychotics in cerebrovascular surgeries.

Postoperative Intracerebral Hemorrhage After Combined Revascularization Surgery in Moyamoya Disease: Profiles and Clinical Associations

OBJECTIVE

In combined revascularization surgery for patients with moyamoya disease, intracerebral hemorrhage (ICH) during the postoperative acute phase is a rarely observed but severe complication. Its clinical features remain unclear because of its low incidence rate. The aim of this study was to clarify the clinical characteristics of immediate postoperative ICH.

METHODS

The frequency, onset timing, and hematoma location of patients who demonstrated immediate postoperative ICH were investigated in 201 consecutive surgeries performed in 134 patients. Associations between immediate postoperative ICH and demographics, clinical presentation type, perioperative blood pressure (BP), and neuroimaging data were analyzed.

RESULTS

Postoperative ICH was observed in 6 cases (2.99%; mean age, 46.0 ± 7.6 years). The onset timing of ICH was within 24 hours after surgery in most patients (83.3%). Hematomas were located at the subcortical lesion beneath the anastomosed cortex (n = 5) and caudate head (n = 1). Three cases (50.0%) required hematoma evacuation. A higher age at surgery was associated with postoperative ICH (P = 0.046). In adult cases (132 surgeries, 65.7%), hemorrhagic presentation at onset (P = 0.0027) and an increase in BP from pre- to postoperative stage (systolic BP increase: P = 0.0058, diastolic BP increase: P = 0.0274) were significantly associated with postoperative ICH.

CONCLUSIONS

The results suggest that older patients, with hemorrhagic presentation and greater postoperative BP increase, should be carefully managed to avoid postoperative ICH. Immediate hematoma evacuation may be effective in preventing devastating outcomes after postoperative ICH.

Intracranial Hemorrhage After Superficial Temporal Artery-Middle Cerebral Artery Direct Anastomosis for Adults with Moyamoya Disease

BACKGROUND

Intracranial hemorrhage, such as intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), and intraventricular hemorrhage (IVH), is an extremely rare complication after surgical revascularization for moyamoya disease (MMD). However, the incidence, timing, prognosis, possible mechanism, and prevention are not well known.

METHODS

Adult patients with MMD who underwent direct bypass or combined bypass and experienced ICH, SAH, or IVH within 7 days postoperatively were enrolled in this study. The medical records and radiologic findings of these patients, together with their intraoperative video recordings, were reviewed retrospectively.

RESULTS

Direct superficial temporal artery (STA)-middle cerebral artery (MCA) bypass or combined bypass was performed for 222 hemispheres in 193 adult patients with MMD between January 2001 and December 2016. Intracranial hemorrhage occurred perioperatively in 8 hemispheres (3.6%) in 8 patients. The hemorrhages developed immediately after STA-MCA direct anastomosis during surgery in 3 patients. Hemorrhage on computed tomography and neurologic deterioration were also observed immediately postoperatively in 2 patients and during the postoperative period in 3 patients. Although 4 patients received medical management, neurosurgical treatment was needed in the other 4 patients. One patient died, and 6 patients were left with moderate or severe disabilities.

CONCLUSIONS

Intracranial hemorrhage (ICH, IVH, or SAH) after direct bypass for adult patients with MMD is an extremely rare but fatal complication. Although these hemorrhages can be associated with hyperperfusion syndrome, no effective prevention has been established.

Factors of Delayed Hyperperfusion and the Importance of Repeated Cerebral Blood Flow Evaluation for Hyperperfusion After Direct Bypass for Moyamoya Disease

OBJECTIVE

Postoperative hyperperfusion is an important complication after direct bypass for moyamoya disease, which sometimes occurs late after initial postoperative cerebral blood flow (CBF) measurement. This study aimed to clarify the incidence of hyperperfusion with management using postoperative continuous sedation and repeated postoperative CBF measurement and to identify factors associated with delayed hyperperfusion.

METHODS

This retrospective study evaluated 72 consecutive hemispheres in 56 adult Japanese patients with moyamoya disease who underwent direct bypass. Postoperative continuous sedation was routinely administered based on CBF evaluation. First, the incidence of symptomatic hyperperfusion was investigated. Second, radiologic hyperperfusion (RHP), which was strictly defined as >30% increase in CBF compared with the contralateral side, and factors associated with delayed RHP were statistically analyzed.

RESULTS

Postoperative symptomatic hyperperfusion occurred in 3 hemispheres (4.2%), including subarachnoid hemorrhage in 1 hemisphere (1.4%). RHP immediately after surgery was identified in 16 hemispheres (22.2%). In 8 hemispheres (11.1%), RHP appeared or worsened several days after initial CBF study. In univariate logistic regression analysis, decreased preoperative cerebral vasoreactivity was significantly associated with delayed RHP.

CONCLUSIONS

The incidence of symptomatic hyperperfusion was 4.2% with management. Delayed hyperperfusion was significantly associated with decreased cerebral vasoreactivity. Therefore, repeated CBF measurements evaluating preoperative cerebral vasoreactivity may decrease complications.

Cerebral Hyperperfusion Syndrome by the Numbers: Transient Focal Neurological Deficit, Imaging-Proven Focal Hyperperfusion, and High Graft Flow Rate Following Superficial Temporal Artery-Middle Cerebral Artery bypass in a Patient With Symptomatic Carotid Occlusion—Case Report

BACKGROUND AND IMPORTANCE

Cerebral hyperperfusion syndrome (CHS) is a well-known complication of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass for ischemic cerebrovascular disease. While this argues against “low flow” in the bypass construct, flow rates in the graft have not been previously quantified in the setting of CHS.

CLINICAL PRESENTATION

A 58-yr-old man presented with recurrent left hemispheric ischemic strokes and fluctuating right hemiparesis and aphasia. Vascular imaging revealed left cervical internal carotid artery occlusion and perfusion imaging confirmed left hemispheric hypoperfusion. After failing to respond to maximal medical therapy, the patient underwent single-barrel STA-MCA bypass. Postoperatively, his symptoms resolved and blood pressure (BP) was strictly controlled within normal range. However, 2 d later, he developed severe expressive aphasia. CTA demonstrated a patent bypass graft and SPECT showed focal hyperperfusion in Broca's speech area. Seizure activity was ruled out. A high graft flow rate of 52 mL/min was documented by quantitative magnetic resonance angiography (MRA). Thus, the diagnosis of CHS was made and managed with strict BP control. The patient exhibited complete recovery of speech over a period of days and was discharged home. Repeat SPECT at 4 mo showed resolution of hyperperfusion and quantitative MRA demonstrated reduction of graft flow rate to 34 mL/min.

CONCLUSION

This is the first case of perfusion imaging-proven CHS after STA-MCA bypass, where high graft flow rates are objectively documented. Our observations constitute irrefutable evidence challenging the classic belief that the STA-MCA bypass is a low-flow construct.

Progressive Cortical Neuronal Damage and Extracranial-Intracranial Bypass Surgery in Patients with Misery Perfusion

BACKGROUND AND PURPOSE

Misery perfusion may cause selective neuronal damage in atherosclerotic ICA or MCA disease. Bypass surgery can improve misery perfusion and may prevent neuronal damage. On the other hand, surgery conveys a risk for neuronal damage. The purpose of this retrospective study was to determine whether progression of cortical neuronal damage in surgically treated patients with misery perfusion is larger than that in surgically treated patients without misery perfusion or medically treated patients with misery perfusion.

MATERIALS AND METHODS

We evaluated the distribution of benzodiazepine receptors twice by using PET and ¹¹C-labeled flumazenil in 18 surgically treated patients with atherosclerotic ICA or MCA disease (9 with misery perfusion and 9 without) and no perioperative stroke before and after bypass surgery; in 8 medically treated patients with misery perfusion and no intervening ischemic event; and in 7 healthy controls. We quantified abnormal decreases in the benzodiazepine receptors of the cerebral cortex within the MCA distribution and compared changes in the benzodiazepine receptor index among the 3 groups.

RESULTS

The change in the benzodiazepine receptor index in surgically treated patients with misery perfusion (27.5 ± 15.6) during 7 ± 5 months was significantly larger than that in surgically treated patients without misery perfusion (-5.2 ± 9.4) during 6 ± 4 months (P < .001) and in medically treated patients with misery perfusion (3.2 ± 15.4) during 16 ± 6 months (P < .01).

CONCLUSIONS

Progression of cortical neuronal damage in surgically treated patients with misery perfusion and no perioperative stroke may occur and may be larger than that in medically treated patients with misery perfusion and no intervening ischemic event.