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.

Effectiveness of indirect revascularization for adult hemorrhagic moyamoya disease: a 10-year follow-up study.

OBJECTIVE: The optimal surgical approach for hemorrhagic moyamoya disease (hMMD) continues to be a topic of debate. The authors' prior research demonstrated that both combined and indirect revascularization were efficacious. However, questions remain regarding the long-term prognosis consistency between these two treatments. Therefore, the objective of this study was to evaluate and compare the enduring effects of these surgical modalities on adult hMMD, extending the findings of the authors' previous studies. METHODS: The authors recruited patients diagnosed with hMMD between 2010 and 2015. The patients were categorized into two groups: those who underwent combined revascularization (superficial temporal artery-middle cerebral artery bypass alongside dural reverse application) and those who underwent indirect revascularization (encephaloduroarteriosynangiosis [EDAS]). The primary and secondary endpoints of this study were instances of rebleeding, confirmed with CT scan, and death resulting from rebleeding, respectively. The authors estimated rebleeding-free and death-free survival rates by utilizing the Kaplan-Meier survival method. They used Cox regression to adjust for confounders and to evaluate the effects of the varying surgical modalities on the endpoints. RESULTS: After an average follow-up period of 114 months, 35 patients (28.6%) experienced 40 rebleeding events, yielding an average annual incidence of 3.5%. Of the 79 patients who received combined revascularization, 17 (21.5%) experienced rebleeding events. Similarly, of 43 patients who underwent EDAS, 18 (41.9%) experienced rebleeding events (p = 0.018). Most rebleeding instances occurred 61-120 months after surgery (21 patients [60%]), followed by 12-60 months (11 patients [31.4%]). Multivariate survival analysis highlighted significant differences in surgical outcomes (HR 0.33, 95% CI 0.15-0.74, p = 0.007). The authors observed that 8 patients (10.1%) died of rebleeding events in the combined group, as well as 10 patients (23.3%) in the EDAS group. Despite the lack of a statistically significant difference in mortality (p = 0.051), multivariable survival analysis found a significant difference (HR 0.31, 95% CI 0.10-0.97, p = 0.044). CONCLUSIONS: High rebleeding rates persist in adult hMMD patients, even after revascularization. Combined revascularization proved superior to EDAS in preventing long-term rebleeding. In contrast, EDAS alone did not display a clear effect on reducing long-term rebleeding rates.

A novel system for evaluating collateralization of the external carotid artery after cerebral revascularization in moyamoya disease.

OBJECTIVE: The objective of this retrospective study was to establish a novel system for evaluating collateralization of the external carotid artery in patients with moyamoya disease (MMD) following direct and indirect revascularization surgeries. METHODS: The authors conducted a retrospective analysis of 456 patients diagnosed with MMD who underwent direct and indirect revascularization procedures at Beijing Tiantan Hospital, Capital Medical University, between January 2015 and May 2023. Using a newly proposed digital subtraction angiography (DSA)-based evaluation system, the authors assessed collateralization angiogenesis objectively and in a standardized manner. RESULTS: The authors' findings indicated that there was no significant difference in collateralization angiogenesis between patients undergoing direct or indirect cerebral revascularization (p = 0.702). However, after cerebral revascularization, patients with ischemic MMD exhibited significantly higher collateralization angiogenesis compared with those with hemorrhagic MMD (p = 0.007). Children with MMD demonstrated higher angiogenesis levels than adults (p < 0.001), but subgroup analysis showed age-specific variations. In adults, collateralization angiogenesis was significantly greater in those with ischemic MMD (p = 0.006), whereas in children, no significant difference was noted between ischemic and hemorrhagic MMD (p = 0.962). Furthermore, regardless of MMD type, direct and indirect revascularization methods yielded similar collateralization angiogenesis (p = 0.962 and p = 0.963, respectively). Importantly, the Matsushima grading system revealed significant differences in angiogenesis in patients with ischemic MMD (p < 0.001). CONCLUSIONS: The newly introduced DSA-based evaluation system offers an objective and standardized method for assessing collateralization angiogenesis in MMD. This study supports the efficacy of both direct and indirect revascularization surgical procedures and highlights distinct pathophysiological processes of ischemic and hemorrhagic disease subtypes. These findings contribute to a better understanding of surgical outcomes and aid in the selection of appropriate treatment strategies for patients with MMD.

Hemorrhage Risk in Moyamoya Disease with Fetal-Type Posterior Cerebral Artery: A Propensity Score-Matched Analysis.

OBJECTIVE: Patients with moyamoya disease (MMD) and fetal-type posterior cerebral arteries have not been thoroughly investigated as yet. We focused on the risk of intracranial hemorrhage in patients with MMD and fetal-type posterior cerebral arteries. METHODS: We reviewed 2422 patients with MMD diagnosed at the Neurosurgical Department of Beijing Tiantan Hospital between May 2009 and December 2020. We classified patients into 2 groups according to whether they had a fetal-type posterior cerebral artery. After 1:1 propensity score matching, hemorrhagic tendency and Suzuki stage were compared between patients with a fetal-type posterior cerebral artery (group I) and patients without a fetal-type posterior cerebral artery (group II). RESULTS: In total, 2415 patients were included in this study; 181 had fetal-type posterior cerebral arteries. Hemorrhagic events were more frequently observed in patients with fetal-type posterior cerebral artery development than in those without it (28.2% vs. 18.8%, P = 0.035). However, Suzuki stages did not differ between the 2 matched groups (4.03 vs. 4.20, P = 0.081). CONCLUSIONS: Hemorrhagic events occurred more frequently in patients with MMD with fetal-type posterior cerebral arteries than in those without.

Assessment of Surgical Outcomes in Children and Adult Ischemic Moyamoya Disease and Its Relationship with the Pre-infarction Cerebral Perfusion Status.

AIM: To clarify perfusion differences, and to determine whether children and adults respond similarly to surgical prevention and how brain perfusion stages before surgery predict outcomes in ischaemic moyamoya disease (MMD) in children and adults. MATERIAL AND METHODS: A total of 355 patients with ischaemic MMD, including 74 children and 281 adults, were enrolled in the study. Computerized tomography perfusion (CTP) scans were used to identify the perfusion status according to a novel staging system of the pre-infarction period. The perfusion status of each hemisphere between the children and adult groups was analysed. The modified Rankin scale was used during long-term follow-up as an indicator of clinical outcomes. RESULTS: The proportions of stages 0 and IV in adults were significantly higher than those in children (p=0.09 and p=0.003, respectively). Stage III was more common in the children's group (p=0.001). The stroke data showed an increasing tendency in the infarction rate from stages I to IV. Both groups in stage 0 and in the early stages had a similar highly improved ratio after surgery; the children, however, achieved significantly better clinical outcomes in stage III and late stages. CONCLUSION: There are differences in the perfusion status between child and adult patients with MMD. The pre-infarction staging system is associated with MMD-related stroke to some extent. Children have a greater chance for improvement than adults in stage III and later stages.

Measurement of Cortical Atrophy and Its Correlation to Memory Impairment in Patients With Asymptomatic Carotid Artery Stenosis Based on VBM-DARTEL.

OBJECTIVE: Severe carotid artery stenosis (CAS) can lead to atrophy of gray matter (GM) and memory impairment; however, the underlying mechanism is unknown. Thus, we aimed to identify memory impairment and GM atrophy and explore the possible correlation between them in patients with asymptomatic severe CAS. METHODS: Twenty-four patients with asymptomatic severe CAS and 10 healthy controls completed the mini-mental state examination (MMSE) and clinical memory scale (CMS) and underwent 7T magnetic resonance imaging (MRI) scan. Field intensity inhomogeneities were corrected. Images were processed using VBM8, and GM images were flipped. First, 11 flipped and 10 non-flipped images of patients with unilateral CAS and 5 flipped and 5 non-flipped images of controls were pre-processed using DARTEL algorithm and analyzed using an analysis of variance (ANOVA). Second, flipped and non-flipped images of unilateral patients were similarly pre-processed and analyzed using the paired t-test. Third, pre-processed non-flipped GM images and CMS scores of 24 patients were analyzed by multiple regression analysis. Nuisance variables were corrected accordingly. RESULTS: Basic information was well matched between patients and controls. MMSE scores of patients were in the normal range; however, memory function was significantly reduced (all P < 0.05). GM volumes of patients were significantly reduced in the anterior circulation regions. The stenosis-side hemispheres showed greater atrophy. GM volumes of the left pars opercularis, pars triangularis, and middle frontal gyrus were strongly positively correlated with the total scores of CMS (all r > 0.7, P = 0.001). Additionally, the left middle frontal gyrus was strongly positively correlated with associative memory (r = 0.853, P = 0.001). The left pars opercularis was moderately positively correlated with semantic memory (r = 0.695, P = 0.001). CONCLUSION: Patients with asymptomatic CAS suffer from memory impairment. Bilateral anterior circulation regions showed extensive atrophy. The hemisphere with stenosis showed severer atrophy. Memory impairment in patients may be related to atrophy of the left frontal gyrus and atrophy of different regions may result in different memory impairments.