Analysis of rescue strategies for acute thrombosis during STA-MCA bypass surgery and the literature review.

BACKGROUND AND OBJECTIVES: STA-MCA bypass surgery is mainly used for Moyamoya disease, giant intracranial aneurysms, and resection of intracranial tumors requiring sacrifice of blood vessels. The intraoperative patency of the reconstructive vessels is critical to the efficacy of the procedure. This study aimed to evaluate the efficacy of intra-arterially infused tirofiban for the treatment of acute thrombosis during STA-MCA bypass surgery and countermeasures for acute thrombosis. METHODS: This study involved 209 patients (272 hemispheres) who underwent STA-MCA surgery between November 2020 and December 2023. Intraoperative acute thrombosis occurred in eight patients (3.83%,8 hemispheres). We retrospectively reviewed the clinical and imaging data, surgical procedure, and follow-up outcomes of eight patients. We implemented the different thrombolytic methods to evaluate the optimal thrombosis management during the bypass surgery. After three months, we assessed neurological functions using the modified Rankin Scale (mRS) and conducted a literature review using PubMed. RESULTS: Eight patients (four male patients and four female patients) developed acute thrombosis during the bypass surgery. Of the eight patients, two underwent re-anastomosis after thrombus removal, three received local injections of tirofiban into the anastomosis or the branches of the superficial temporal artery, and three underwent superselective intra-arterial tirofiban infusion using a microcatheter. Thrombosis were resolved, and arteries were recanalized in all patients. The mRS score was 0 in all patients. No major ischemic or hemorrhagic complications occurred. CONCLUSION: Our treatment methods were efficacious in the management of acute thrombosis. Intra-arterial tirofiban administration seems to be a simple and effective treatment option for acute thrombosis during STA-MCA bypass surgery.

Prediction of cerebral infarction after bypass surgery in adult moyamoya disease: using pulsatility index on TCD.

BACKGROUND: At present, the most effective treatment for symptomatic moyamoya disease (MMD) is surgery. However, the high incidence of postoperative complications is a serious problem plaguing the surgical treatment of MMD, especially the acute cerebral infarction. Decreased cerebrovascular reserve is an independent risk factor for ischemic infarction, and the pulsatility index (PI) of transcranial Doppler (TCD) is a common intuitive index for evaluating intracranial vascular compliance. However, the relationship between PI and the occurrence of ischemic stroke after operation is unclear. OBJECTIVE: To explore whether the PI in the middle cerebral artery (MCA) could serve as a potential predictor for the occurrence of ischemic infarction after bypass surgery in MMD. METHODS: We performed a retrospective analysis of data from 71 patients who underwent combined revascularization surgery, including superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-myo-synangiosis (EDMS). The patients were divided into two groups according to the median of ipsilateral MCA-PI before operation, low PI group (MCA-PI < 0.614) and high PI group (MCA-PI ≥ 0.614). Univariate and multivariate regression analysis were used to explore risk factors affecting the occurrence of postoperative cerebral infarction. RESULTS: Among the 71 patients with moyamoya disease, 11 patients had cerebral infarction within one week after revascularization. Among them, 10 patients' ipsilateral MCA-PI were less than 0.614, and another one's MCA- PI is higher than 0.614. Univariate analysis showed that the lower ipsilateral MCA-PI (0.448 ± 0.109 vs. 0.637 ± 0.124; P = 0.001) and higher Suzuki stage (P = 0.025) were linked to postoperative cerebral infarction. Multivariate analysis revealed that lower ipsilateral MCA-PI was an independent risk factor for predicting postoperative cerebral infarction (adjusted OR = 14.063; 95% CI = 6.265 ~ 37.308; P = 0.009). CONCLUSIONS: A lower PI in the ipsilateral MCA may predict the cerebral infarction after combined revascularization surgery with high specificity. And combined revascularization appears to be safer for the moyamoya patients in early stages.

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.

Vascular risk profile and changes of arterial hypertension after surgical revascularization in adult Moyamoya patients.

Moyamoya disease (MMD) is a rare stenoocclusive cerebral vasculopathy often treated by neurosurgical revascularization using extracranial-intracranial bypasses to prevent ischemic or hemorrhagic events. Little is known about the vascular risk profile of adult MMD patients compared to the general population. We therefore analyzed 133 adult MMD patients and compared them with data from more than 22,000 patients from the German Health Update database. Patients with MMD showed an age- and sex-adjusted increased prevalence of arterial hypertension, especially in women between 30 and 44 years and in patients of both sexes between 45 and 64 years. Diabetes mellitus was diagnosed significantly more frequently in MMD patients with increasing age, whereas the vascular risk profile in terms of obesity, nicotine and alcohol consumption was similar to that of the general population. Antihypertensive medication was changed one year after surgical revascularization in 67.5% of patients with a tendency towards dose reduction in 43.2% of all patients. After revascularization, physicians need to be aware of a high likelihood of changes in arterial hypertension and should adjust all other modifiable systemic vascular risk factors to achieve the best treatment possible.

Development and validation of machine learning models to predict postoperative infarction in moyamoya disease.

OBJECTIVE: Cerebral infarction is a common complication in patients undergoing revascularization surgery for moyamoya disease (MMD). Although previous statistical evaluations have identified several risk factors for postoperative brain ischemia, the ability to predict its occurrence based on these limited predictors remains inadequately explored. This study aimed to assess the feasibility of machine learning algorithms for predicting cerebral infarction after revascularization surgery in patients with MMD. METHODS: This retrospective study was conducted across two centers and harnessed data from 512 patients with MMD who had undergone revascularization surgery. The patient cohort was partitioned into internal and external datasets. Using perioperative clinical data from the internal cohort, three distinct machine learning algorithms-namely the support vector machine, random forest, and light gradient-boosting machine models-were trained and cross-validated to predict the occurrence of postoperative cerebral infarction. Predictive performance validity was subsequently assessed using an external dataset. Shapley additive explanations (SHAP) analysis was conducted to augment the prediction model's transparency and to quantify the impact of each input variable on shaping both the aggregate and individual patient predictions. RESULTS: In the cohort of 512 patients, 33 (6.4%) experienced postrevascularization cerebral infarction. The cross-validation outcomes revealed that, among the three models, the support vector machine model achieved the largest area under the receiver operating characteristic curve (ROC-AUC) at mean ± SD 0.785 ± 0.052. Notably, during external validation, the light gradient-boosting machine model exhibited the highest accuracy at 0.903 and the largest ROC-AUC at 0.710. The top-performing prediction model utilized five input variables: postoperative serum gamma-glutamyl transpeptidase value, positive posterior cerebral artery (PCA) involvement on preoperative MRA, infarction as the rationale for surgery, presence of an infarction scar on preoperative MRI, and preoperative modified Rankin Scale score. Furthermore, the SHAP analysis identified presence of PCA involvement, infarction as the rationale for surgery, and presence of an infarction scar on preoperative MRI as positive influences on postoperative cerebral infarction. CONCLUSIONS: This study indicates the usefulness of employing machine learning techniques with routine perioperative data to predict the occurrence of cerebral infarction after revascularization procedures in patients with MMD.

The Potential Role of Preoperative Posterior Cerebral Artery Involvement in Predicting Postoperative Transient Neurological Deficits and Ischemic Stroke After Indirect Revascularization in Patients With Moyamoya Disease.

OBJECTIVE: Transient neurological deficits (TNDs) are known to develop after direct bypass for Moyamoya disease and may be risk factors for subsequent stroke. However, the factors involved in the development of TNDs and stroke after indirect revascularization alone, including their association with subsequent stroke, remain unclear. The purpose of this study was to investigate this issue. METHODS: The subjects of the study were 30 patients with Moyamoya disease who underwent a total of 40 indirect revascularization procedures at our institution. Clinical and radiological data were collected retrospectively. To examine factors associated with the development of postoperative TND/stroke/asymptomatic disease, the clinical characteristics of each group were statistically compared. RESULTS: The mean age at surgery was 7 years (range 1-63). TNDs developed after surgery in 9 out of 40 patients (22.5%). Stroke in the acute postoperative period occurred in 3 patients (7.5%), all of whom experienced cerebral infarctions. Demographic data and preoperative clinical information were not different between the groups. However, posterior cerebral artery involvement on preoperative imaging was significantly associated with the development of TNDs and stroke (P = 0.006). Furthermore, postoperative stroke was associated with unfavorable outcomes (P = 0.025). CONCLUSIONS: Posterior cerebral artery involvement is significantly associated with the occurrence of TNDs. In contrast, TNDs after indirect revascularization have little relationship with the subsequent development of stroke. TNDs usually resolve without new strokes, and a better understanding of this particular pathology could help establish an optimal treatment regimen.

[Imaging risk factors for postoperative cerebral infarction in adults with ischemic Moyamoya disease].

Objective: To investigate the imaging factors associated with postoperative cerebral infarction in adult patients aged 18 and above with ischemic Moyamoya disease. Methods: The clinical data of adult patients who underwent surgeries for ischemic Moyamoya disease in the Department of Neurosurgery at Peking University International Hospital from October 2015 to October 2020 were retrospectively analyzed. Of the 239 patients, 120 were male and 119 were female, with ages ranging from 18 to 63 (41.7±10.3) years. A total of 239 patients(290 cases) underwent direct and indirect combined revascularization (CR).Gender, age, surgical side, preoperative transient ischemic attack (TIA), presence of old cerebral infarction, and imaging features were compared between the patients with (48 cases) and without (242 cases) cerebral infarction within 1 week after surgery. Multivariate logistic binary regression model was used to analyze the imaging risk factors of postoperative cerebral infarction. Results: Cerebral infarction occurred in 48 cases(16.5%) among the 290 CR group within 1 week after surgery. The proportion of patients with TIA, old cerebral infarction, ICA stenosis, A1 segment stenosis, M1 segment stenosis, abnormal posterior cerebral artery (PCA), and unstable compensation before CR in the cerebral infarction group was higher than that in the non-cerebral infarction group (P<0.05).Preoperative TIA (OR=4.514, 95%CI: 1.920-10.611), old cerebral infarction (OR=2.856,95%CI:1.176-6.936), A1 stenosis (OR=7.027,95%CI:1.877-26.308), M1 stenosis (OR=6.968,95%CI:2.162-22.459), abnormal PCA (OR=4.114,95%CI:1.330-12.728)and unstable compensation (OR=4.488,95%CI:1.194-16.865) were risk factors for cerebral infarction after CR surgery (all P<0.05). Conclusion: Among the imaging factors, TIA, old cerebral infarction, A1 stenosis, M1 stenosis, abnormal PCA and unstable compensation were risk factors for cerebral infarction in adult patients with ischemic Moyamoya disease treated by combined revascularization.

Risk Factors for Specific Postoperative Ischemic Complications in Patients with Moyamoya Disease: A Single-Center Retrospective Study.

AIM: To evaluate and compare postoperative ischemic complications to determine the risk factors for ischemic complications following revascularization surgery for Moyamoya disease (MMD). MATERIAL AND METHODS: This single-center retrospective study included 266 procedures between 2016 and 2021. Three types of revascularization approaches including direct bypass, indirect bypass, and combined bypass were performed. To identify risk factors for postoperative ischemic complications and contralateral cerebral infarction, preoperative clinical characteristics and radiographic features were examined using multivariate and ordinal logistic regression analyses. RESULTS: Postoperative ischemic complications occurred in 103 (6.6%) procedures. Ischemic presentation (p=0.001, odds ratios [OR] 5.59, 95% confidence interval [CI] 2.05-15.23), hypertension (p=0.030, OR 2.75, 95%CI 1.11- 6.83), advanced Suzuki stage (p=0.006, OR 3.19, 95%CI 1.40-7.26), and collateral circulation (p=0.001 OR 0.17, 95%CI 0.06-0.47) were risk factors for postoperative ischemic complications. Ordinal regression analysis revealed that unilateral involvement (p=0.043, OR 2.70, 95%CI 0.09-5.31), hemorrhagic presentation (p=0.013, OR 3.45, 95%CI 0.72-6.18), surgical approach (p=0.032, OR -1.38, 95%CI -2.65, -0.12), and collateral circulation [p=0.043, OR -1 .27, 95%CI -2.51, -0.04)] were associated with the type of ischemic complications. History of hypertension (p=0.031) and contralateral computed tomography (CT) perfusion stage (p=0.045) were associated with contralateral infarction. CONCLUSION: Inability of cerebral vessels to withstand changes in blood pressure induced by revascularization-related hemodynamic instability might be associated with postoperative complications in patients with Moyamoya disease.

Nonalcoholic fatty liver disease is an independent risk factor for ischemic stroke after revascularization in patients with Moyamoya disease: a prospective cohort study.

BACKGROUND: The study aimed to investigate the association between nonalcoholic fatty liver disease (NAFLD) and ischemic stroke events after revascularization in patients with Moyamoya disease (MMD). METHODS: This study prospectively enrolled 275 MMD patients from September 2020 to December 2021. Patients with alcoholism and other liver diseases were excluded. NAFLD was confirmed by CT imaging or abdominal ultrasonography. Stroke events and modified Rankin Scale (mRS) scores at the latest follow-up were compared between the two groups. RESULTS: A total of 275 patients were enrolled in the study, among which 65 were diagnosed with NAFLD. Univariate logistic regression analysis showed that NAFLD (P = 0.029) was related to stroke events. Multivariate logistic regression analysis showed that NAFLD is a predictor of postoperative stroke in MMD patients (OR = 27.145, 95% CI = 2.031-362.81, P = 0.013). Kaplan-Meier analysis showed that compared with MMD patients with NAFLD, patients in the control group had a longer stroke-free time (P = 0.004). Univariate Cox analysis showed that NAFLD (P = 0.016) was associated with ischemic stroke during follow-up in patients with MMD. Multivariate Cox analysis showed that NAFLD was an independent risk factor for stroke in patients with MMD (HR = 10.815, 95% CI = 1.259-92.881, P = 0.030). Furthermore, fewer patients in the NAFLD group had good neurologic status (mRS score ≤ 2) than the control group (P = 0.005). CONCLUSION: NAFLD was an independent risk factor for stroke in patients with MMD after revascularization and worse neurological function outcomes.

Safety of antiplatelet therapy during the perioperative period of revascularization surgery for moyamoya disease patients with ischemic onset.

For patients with moyamoya disease, antiplatelet agents are often used during the perioperative periods of revascularization surgeries to prevent ischemic events. However, antiplatelet therapy is associated with the risk of hemorrhagic complications. Further, the influence of antiplatelet therapy on perioperative ischemic or hemorrhagic complications has not been investigated. This study aimed to determine the impact of antiplatelet agents on adult moyamoya disease patients with ischemic onset during the perioperative period. From January 2016 to December 2020, 183 consecutive combined (direct and indirect) revascularization surgeries for moyamoya disease patients were performed. Among these surgeries, 96 consecutive combined revascularization surgeries for adult moyamoya disease patients with ischemic onset were analyzed and perioperative ischemic and hemorrhagic complications were reviewed. Antiplatelet agents were continued during the perioperative period including on the day of surgery and the day after the surgery. Among 96 surgeries, no hemorrhagic complications occurred postoperatively. Infarction occurred in five cases (5.2%). Among the five cases, neurological deficits persisted in two cases and improved in three. The median value of bleeding volume was 112.5 mL (interquartile range, 80.0 - 200.0). Twenty-five cases (26.0%) needed blood transfusion. The modified Rankin Scale score deteriorated in two cases due to cerebral infarction. The incidence of hemorrhagic and ischemic complications after combined revascularization surgery in patients with ischemic moyamoya disease under antiplatelet therapy was low, indicating the safety of continued antiplatelet therapy.

Risk Factors for Cerebral Hyperperfusion Syndrome After Combined Revascularization in Adult Patients with Moyamoya Disease.

BACKGROUND: Cerebral hyperperfusion syndrome (CHS) is known as a complication after bypass surgery for Moyamoya disease (MMD). However, the incidence of CHS has not been accurately reported, and there is no consensus on the risk factors associated with it. AIM: The aim of this study was to determine the risk factors associated with postoperative CHS after surgical combined revascularization used to treat adult patients with MMD. OBJECTIVE: To assess the frequency and characteristics of CHS in patients with MMD after revascularization operations. METHODS: Patients who received combined revascularization from Jan 2021 to Nov 2022 were retrospectively reviewed. Preoperative clinical characteristics and radiographic features were recorded. Postoperative CHS after surgery were examined. Multivariate logistic regression analyses were performed to identify the risk factors for CHS. RESULTS: A total of 133 patients (141 hemispheres) were included in this study. Postoperative CHS were observed in 28 hemispheres (19.8%), including focal cerebral hyperperfusion syndrome (FCHS) in 20 hemispheres (14.2%), hemorrhage in 4 (2.8%) hemispheres, seizures in 4 (2.8%) hemispheres. The results of multivariate logistic regression analysis indicated that preoperative hypertension (OR 4.705, 95% CI 1.323 ~ 12.554, p = 0.014), cerebral hemorrhage onset (OR 5.390, 95% CI 1.408 ~ 20.642, p = 0.014) and higher Hct level (OR 1.171, 95% CI 1.051 ~ 1.305, p = 0.004) were significantly associated with CHS after combined revascularization. CONCLUSIONS: Preoperative hypertension, cerebral hemorrhage onset, and higher Hct level were independent risk factors for CHS after combined revascularization.

Longitudinal evaluation of cerebral perfusion evolution after revascularization surgery in moyamoya disease by CT perfusion.

OBJECTIVE: To assess the longitudinal evolution of cerebral perfusion after revascularization surgery in patients with moyamoya disease (MMD) by CT perfusion (CTP). MATERIALS AND METHODS: Thirty-one clinically confirmed MMD patients (12 males and 19 females, average age: 33.26 y, Suzuki stages 3 and 4: 19 and 11, respectively) who underwent revascularization surgery (bilateral (n=13) or unilateral (n=18)) were studied retrospectively. All patients underwent CTP examinations before and in the week after surgery and long-term (>3 months). CTP metrics (CBF, CBV, MTT, TTP, and delay TTP) were derived. The corresponding CTP metric values of the ROIs, which were manually drawn in the white matter (WM) and gray matter (GM), were recorded. RESULTS: Six patients developed a new or progressive cerebral infarction/hemorrhage. In all patients, compared with the preoperative level, the TTP of GM and WM decreased in the short term after the surgery (P ≤ 0.005). Concurrently, the WM CBF increased significantly a week after surgery (P =0.02). However, in the long-term follow-up, the CBV and CBF in the GM and WM decreased to equal to or lower than the preoperative level, especially for CBV in the WM (P =0.012). Furthermore, cerebral perfusion began to decrease in the sixth month, and a continuous decline was observed over the next two months. It returned to the presurgical level after one year. In addition, the improvement in postsurgical perfusion was greater in Suzuki stage 3 patients than stage 4 patients. CONCLUSION: Cerebral perfusion in patients with MMD improved shortly after surgery. However, in the long-term, brain perfusion decreased, most seriously in 6-8 months postoperatively, which might indicate that patients with MMD need timely follow-up and long-term intervention.

Long-term Outcomes of Combined Revascularization Surgery for Moyamoya Disease in the Elderly: A Single Institute Experience.

The opportunity to treat older patients with Moyamoya disease (MMD) is increasing. However, the surgical outcomes after combined direct and indirect revascularization for elderly patients with MMD are not fully understood, especially for those ≥60 years old. This retrospective study examined 232 consecutive hemispheres of 165 adults with MMD who underwent combined revascularization. Clinical features and surgical outcomes were compared between the elderly (≥60 years) and nonelderly group (<60 years). Thirteen (5.6%, 64.4 ± 4.0 years old) and 219 hemispheres (94.4%, 40.2 ± 10.8 years old) were included in the elderly and nonelderly group, respectively. The proportion of clinical presentations before surgery did not differ. However, the prevalence of hypertension and hyperlipidemia was significantly higher in the elderly group than in the nonelderly group. Meanwhile, hyperthyroidism was observed only in the nonelderly group. No significant intergroup differences were observed in the incidence of perioperative complications occurring within four weeks postsurgery. Notably, the elderly group was more prone to develop perioperative intracerebral hemorrhage (odds ratio (OR) 3.14, 95% confidence interval (CI) 0.45-13.5) than the nonelderly group. During a median follow-up period of 7.8 years, the incidence of stroke recurrence occurring later than four weeks postsurgery was not significantly different between the groups (hazard ratio, 1.19; 95% CI 0.133-10.6). The prevalence of independent outcomes (76.9% vs. 90.4%, P = 0.14) and mortality (7.7% vs. 1.4%, P = 0.21) did not differ significantly between the elderly and nonelderly groups, respectively. Perioperative intracerebral hemorrhage may be common in the elderly and should be considered to achieve a favorable surgical outcome.

Complications associated with combined direct and indirect bypass in Moyamoya Disease: A meta-analysis.

Bypass revascularization helps prevent complications in Moyamoya Disease (MMD). To systematically review complications associated with combined direct and indirect (CB) bypass in MMD and analyze differences between the adult and pediatric populations. A systematic literature review was conducted per PRISMA guidelines. PUBMED, Cochrane Library, Web of Science, and CINAHL, were queried from January 1980 to March 2022. Complications were defined as any event in the immediate post-surgical period of a minimum 3 months follow-up. Exclusion criteria included lack of surgical complication reports, non-English articles, and CB unspecified or reported separately. 18 final studies were included of 1580 procured. 1151 patients (per study range = 10-150, mean = 63.9) were analyzed. 9 (50.0%) studies included pediatric patients. There were 32 total hemorrhagic, 74 total ischemic and 16 total seizure complications, resulting in a rate of 0.04 (95% CI 0.03, 0.06), 0.7 (95% CI 0.04, 0.10) and 0.03 (95% CI 0.02, 0.05), respectively. The rate of hemorrhagic complications in the pediatric showed no significant difference from the adult subgroup (0.03 (95% CI 0.01-0.08) vs. 0.06 (95% CI 0.04-0.10, p = 0.19), such as the rate of ischemic complications (0.12 (95% CI 0.07-0.23) vs. 0.09 (95% CI 0.05-0.14, p = 0.40). Ischemia is the most common complication in CB for MMD. Pediatric patients had similar hemorrhagic and ischemic complication rates compared to adults.

Direct Versus Indirect Revascularization for Moyamoya: a Large Multicenter Study.

BACKGROUND: Moyamoya is a chronic occlusive cerebrovascular disease of unknown etiology causing neovascularization of the lenticulostriate collaterals at the base of the brain. Although revascularization surgery is the most effective treatment for moyamoya, there is still no consensus on the best surgical treatment modality as different studies provide different outcomes. OBJECTIVE: In this large case series, we compare the outcomes of direct (DR) and indirect revascularisation (IR) and compare our results to the literature in order to reflect on the best revascularization modality for moyamoya. METHODS: We conducted a multicenter retrospective study in accordance with the Strengthening the Reporting of Observational studies in Epidemiology guidelines of moyamoya affected hemispheres treated with DR and IR surgeries across 13 academic institutions predominantly in North America. All patients who underwent surgical revascularization of their moyamoya-affected hemispheres were included in the study. The primary outcome of the study was the rate of symptomatic strokes. RESULTS: The rates of symptomatic strokes across 515 disease-affected hemispheres were comparable between the two cohorts (11.6% in the DR cohort vs 9.6% in the IR cohort, OR 1.238 (95% CI 0.651 to 2.354), p=0.514). The rate of total perioperative strokes was slightly higher in the DR cohort (6.1% for DR vs 2.0% for IR, OR 3.129 (95% CI 0.991 to 9.875), p=0.052). The rate of total follow-up strokes was slightly higher in the IR cohort (8.1% vs 6.6%, OR 0.799 (95% CI 0.374 to 1.709) p=0.563). CONCLUSION: Since both modalities showed comparable rates of overall total strokes, both modalities of revascularization can be performed depending on the patient's risk assessment.

Pediatric Moyamoya Revascularization Perioperative Care: A Modified Delphi Study.

BACKGROUND: Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities. METHODS: Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement. RESULTS: Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery. CONCLUSIONS: In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.

Effect of thin-split encephalomyosynangiosis on transient neurological events in revascularization surgery for pediatric patients with moyamoya disease.

OBJECTIVE: Transient neurological events (TNEs) are among the most important events after revascularization surgery in pediatric patients with moyamoya disease (MMD). Although hemodynamic changes and crying are representative factors of TNEs, brain compression by encephalomyosynangiosis (EMS) is another important cause of TNEs. Therefore, the authors assumed that making the EMS as thin as possible reduces the frequency of TNEs. However, thin-split EMS can lead to insufficient development of collateral vessels. This study aimed to evaluate the effects of thin-split EMS in combined revascularization surgery on postoperative outcomes in pediatric patients with MMD. METHODS: The authors retrospectively included 56 consecutive combined revascularization surgeries in the anterior cerebral circulation in pediatric patients with MMD. These surgeries were classified into the former group and thin-split EMS group. The temporal muscle was halved in the former EMS group and split as thinly as possible in the thin-split EMS group. The authors performed between-group comparisons of postoperative stroke events and TNEs during the acute period and the development of collateral flow and stroke events during the chronic period. RESULTS: Former and thin-split EMS procedures were performed in 37 and 19 patients, respectively. TNEs without crying or hemodynamic changes were observed significantly less frequently in the thin-split EMS group than in the former EMS group (0 [0.0%] in the thin-split EMS group vs 9 [24.3%] in the former EMS group, p = 0.021). There were no significant between-group differences in the development of indirect bypass during the chronic period (good: 34 [91.9%] and poor: 3 [8.1%] in the former EMS group vs good: 16 [84.2%] and poor: 3 [15.8%] in the thin-split EMS group; p = 0.397). Additionally, there were no significant between-group differences in the incidence of chronic clinical events, including death or stroke. CONCLUSIONS: Thin-split EMS can reduce TNEs that do not accompany crying or hemodynamic changes. Furthermore, the procedure has sufficient prevention effects against stroke events during the chronic postoperative period in pediatric patients with MMD.

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.