Surgical therapy for adult moyamoya disease. Can surgical revascularization prevent the recurrence of intracerebral hemorrhage?

Outcomes of Bypass Surgery in Adult Moyamoya Disease by Onset Type

Importance

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

Objective

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

Design, Setting, and Participants

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

Exposures

Bypass surgery and conservative management.

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

Is medical management useful in Moyamoya disease?

Moyamoya disease (MMD), characterized by progressive internal carotid artery stenosis and collateral vessel formation, prompts cerebral perfusion complications and is stratified into idiopathic and Moyamoya syndrome subtypes. A multifaceted approach toward MMD management addresses cerebral infarctions through revascularization surgery and adjunctive medical therapy, while also navigating risks such as intracranial hemorrhage and cerebral infarction resulting from arterial stenosis and fragile collateral vessels. Addressing antithrombotic management reveals a potential role for treatments like antiplatelet agents and anticoagulants, despite the ambiguous contribution of thrombosis to MMD-related infarctions and the critical balance between preventing ischemic events and averting hemorrhagic complications. Transcranial doppler has proven useful in thromboembolic detection, despite persisting challenges concerning the efficacy and safety of antithrombotic treatments. Furthermore, antihypertensive interventions aim to manage blood pressure meticulously, especially during intracerebral hemorrhage, with recommendations and protocols varying based on the patient's hypertension status. Additionally, lipid-lowering therapeutic strategies, particularly employing statins, are appraised for their possible beneficial role in MMD management, even as comprehensive data from disease-specific clinical trials remains elusive. Comprehensive guidelines and protocols to navigate the multifaceted therapeutic avenues for MMD, while maintaining a delicate balance between efficacy and safety, warrant further meticulous research and development. This protocol manuscript seeks to elucidate the various aspects and challenges imbued in managing and navigating through the complex landscape of MMD treatment.

Revascularization Surgery for Moyamoya Vasculopathy: An Australian Experience

BACKGROUND

Moyamoya vasculopathy is a rare steno-occlusive cerebrovascular disorder presenting with ischemia or hemorrhage. There are racial and geographic differences in presentation and outcome. There is little information regarding moyamoya in Australia.

METHODS

Moyamoya patients undergoing surgery from 2001 to 2022 were studied retrospectively. The outcomes of revascularization surgery in adult and pediatric patients, with ischemic and hemorrhagic disease were analyzed, including functional outcomes, postoperative complications, bypass patency, and long-term rates of ischemic and hemorrhagic events.

RESULTS

A total of 68 patients with 122 revascularized hemispheres and 8 posterior circulation revascularizations were included in this study. Eighteen patients were of Asian descent and 46 were of Caucasian origin. Presentation was with ischemia in 124 hemispheres and hemorrhage in six hemispheres. There were 92 direct, 34 indirect, and 4 combined revascularization surgeries performed. Early postoperative complications occurred in 3.1% (n = 4) of operations and delayed complications (infection, subdural hematoma) occurred after 4.6% (n = 6) of operations. Mean follow-up was 6.5 years (3-252 months). There was 100% patency of direct grafts at last follow-up. There were no hemorrhagic events following surgery and 1 new ischemic event 2 years after surgery. There was significant improvement in physical health functional outcomes at most recent follow-up (P < 0.05); mental health outcomes were not different between preoperative and postoperative assessments.

CONCLUSIONS

The majority of Australian moyamoya patients are Caucasian and the most common clinical presentation is ischemia. Revascularization surgery had excellent outcomes with very low rates of ischemia and hemorrhage, comparing favorably to the natural history of moyamoya vasculopathy.

Risk factors and a novel cerebral infarction extent scoring system for postoperative cerebral ischemia in patients with ischemic Moyamoya disease

Postoperative cerebral ischemic complication is the most common complication of revascularization surgery for patients with moyamoya disease (MMD). This retrospective study was conducted on 63 patients with ischemic MMD. Postoperative ischemia occurred in 15 of the 70 revascularization operations performed for patients after surgical revascularization, translating to an incidence of 21.4%. Univariate analysis revealed that onset infarction (p = 0.015), posterior cerebral artery involvement (p = 0.039), strict perioperative management (p = 0.001), interval time between transient ischemic attack (TIA) or infarction presentation and operation (p = 0.002) and preoperatively cerebral infarction extent score (CIES) (p = 0.002) were significantly associated with postoperative cerebral ischemia. Multivariate analysis revealed that strict perioperative management (OR = 0.163; p = 0.047), and preoperatively CIES (OR = 1.505; p = 0.006) were independently associated with postoperative cerebral ischemia-related complications. After comprehensive improvement of perioperative management protocol, the incidence of symptomatic infarction declined to 7.4% (4 out of 54). Analysis of the area under the receiver operating characteristic curve (AUROC) indicated CIES was a predictor for both postoperative ischemia and high follow-up modified Rankin Scale scores. In summary, strict perioperative management and CIES were identified as independent risk factors for postoperative ischemic complications in ischemic MMD, demonstrating that comprehensive and individualized perioperative management improve postoperative outcomes in patients with MMD. Furthermore, application of CIES to evaluate pre-existing cerebral infarction can improve the management of patients.

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.

Short- and long-term outcomes of moyamoya patients post-revascularization

OBJECTIVE

The post-bypass stroke risk factors and long-term outcomes of moyamoya patients are not well documented. Therefore, the authors studied 30-day stroke risks and patients’ long-term physical, functional, and social well-being.

METHODS

This was a single-institution combined moyamoya disease (MMD) database interrogation and questionnaire study. From 1991 to 2014, 1250 revascularization procedures (1118 direct bypasses, 132 indirect bypasses) were performed in 769 patients. Completed questionnaires were received from and available for analysis on 391 patients, and 6-month follow-up data were available for 96.4% (741/769) of the patients.

RESULTS

The patients consisted of 548 females and 221 males, with a mean age of 32 years (range 1–69 years). Three hundred fifty-eight bypasses were performed in 205 pediatric patients (73% direct bypasses), and 892 revascularizations were performed in 564 adults (96% direct bypasses). Fifty-two patients (6.8%) developed major strokes with a worsening modified Rankin Scale (mRS) score within 30 days postoperatively. The 30-day major stroke risk was 5.3% (41/769) and 2.6% (12/467) after the first and second bypasses, respectively. Logistic regression analysis revealed that older age, modified MRI (mMRI) score, and hemodynamic reserve (HDR) score are clearly associated with higher postoperative stroke risks. Over a mean follow-up of 7.3 years (range 0.5–26 years), the long-term stroke risk among 741 patients was 0.6% per patient-year; 75% of these patients had excellent outcomes (mRS score 0–1). The long-term outcome questionnaire study showed that 84% (234/277) of patients reported resolution or improvement in their preoperative headache, 83% (325/391) remained employed or in school, and 87% (303/348) were self-caring.

CONCLUSIONS

In this large, single-center surgical series, most of the adult and pediatric patients had direct revascularization, with a 4.2% per-bypass-procedure (6.8% per patient) 30-day major stroke risk and a 0.6% per-patient-year long-term stroke risk. The authors identified various risk factors that are highly correlated with postoperative morbidity (age, mMRI score, and HDR score) and are involved in ongoing work to develop the predictive modeling for future patient selection and treatment.

STA-A3 Bypass Using Radial Artery Graft for Progressive Cerebral Infarction of Bilateral ACA Region after STA-MCA Bypass Surgery for Moyamoya Disease

Direct revascularization surgery, such as superficial temporal artery (STA)-middle cerebral artery (MCA) bypass, is effective in preventing ischemia and hemorrhage for moyamoya disease. On the other hand, when ischemia of the anterior cerebral artery (ACA) region progresses after ipsilateral STA-MCA bypass, it is difficult to perform revascularization from the viewpoint of the donor artery. A 55-year-old woman with right hemiparesis was diagnosed with cerebral infarction due to moyamoya disease. Left STA-MCA bypass was performed with no postoperative complications, but memory impairment and decreased motivation were observed 2 months after the operation. Magnetic resonance imaging and angiography revealed new infarction in the bilateral ACA area and deterioration in the signal intensity of bilateral ACAs. Revascularization of the bilateral ACA regions was considered necessary, but the left STA was already used in the previous surgery. Therefore, STA-radial artery (RA)-A3 bypass using RA graft combined with right STA-MCA bypass was performed. STA-A3 bypass using an RA graft may be the optimal treatment for ischemia of the ACA region that progresses after STA-MCA bypass.

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.

Recognition of the Effect of Indirect Revascularization for Moyamoya Disease: The Balance Between the Stage Progression and Neoangiogenesis

Objective

To explore the long-term progression of neoangiogenesis after indirect revascularization for moyamoya disease (MMD).

Methods

We enrolled patients who were diagnosed with MMD and treated by encephaloduroarteriosynangiosis (EDAS) surgery at our center from December 2002 through September 2009. A comparative study between short-term (6–12 months) and long-term (duration ≥ 8 years) follow-up angiographies was performed. The development of collateral circulation through EDAS was graded according to the system described by the Matsushima grade system.

Results

A total of 78 patients who received indirect EDAS were enrolled in the study. The mean age at the first operation was 26.9 ± 15.0 years. The Matsushima grades of the same hemisphere were higher at the long-term follow-up compared with the short-term follow-up. Importantly, no attenuation was observed in any hemisphere during the long-term follow-up. In total, 51 hemispheres (32.7%) and 26 hemispheres (16.6%) had progression during the short-term and the long-term follow-up, respectively. The ipsilateral Suzuki stage showed a significant negative correlation with progression pace. Furthermore, higher Suzuki stages were significantly correlated with the postsurgical Matsushima grade at both time points. A total of nine strokes (11.5%) occurred in 78 patients was reported at the long-term follow-up. The annual incidence rate of recurrent strokes was higher for the stage progression group than for the stable group.

Conclusion

For patients with MMD, postsurgical neoangiogenesis after indirect bypass continuously improved with time. The short-term progression of the internal carotid artery (ICA) might be attributed to cerebral revascularization, while the long-term progression should be attributed to the natural progression of the disease.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Macrohistory of Moyamoya Disease Analyzed Using Artificial Intelligence

INTRODUCTION

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

RESULTS

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

CONCLUSION

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

Recognition of moyamoya disease and its hemorrhagic risk using deep learning algorithms: sourced from retrospective studies

Although intracranial hemorrhage in moyamoya disease can occur repeatedly, predicting the disease is difficult. Deep learning algorithms developed in recent years provide a new angle for identifying hidden risk factors, evaluating the weight of different factors, and quantitatively evaluating the risk of intracranial hemorrhage in moyamoya disease. To investigate whether convolutional neural network algorithms can be used to recognize moyamoya disease and predict hemorrhagic episodes, we retrospectively selected 460 adult unilateral hemispheres with moyamoya vasculopathy as positive samples for diagnosis modeling, including 418 hemispheres with moyamoya disease and 42 hemispheres with moyamoya syndromes. Another 500 hemispheres with normal vessel appearance were selected as negative samples. We used deep residual neural network (ResNet-152) algorithms to extract features from raw data obtained from digital subtraction angiography of the internal carotid artery, then trained and validated the model. The accuracy, sensitivity, and specificity of the model in identifying unilateral moyamoya vasculopathy were 97.64 ± 0.87%, 96.55 ± 3.44%, and 98.29 ± 0.98%, respectively. The area under the receiver operating characteristic curve was 0.990. We used a combined multi-view conventional neural network algorithm to integrate age, sex, and hemorrhagic factors with features of the digital subtraction angiography. The accuracy of the model in predicting unilateral hemorrhagic risk was 90.69 ± 1.58% and the sensitivity and specificity were 94.12 ± 2.75% and 89.86 ± 3.64%, respectively. The deep learning algorithms we proposed were valuable and might assist in the automatic diagnosis of moyamoya disease and timely recognition of the risk for re-hemorrhage. This study was approved by the Institutional Review Board of Huashan Hospital, Fudan University, China (approved No. 2014-278) on January 12, 2015.

Late (5-20 years) outcomes after STA-MCA anastomosis and encephalo-duro-myo-arterio-pericranial synangiosis in patients with moyamoya disease

OBJECTIVE

Surgical revascularization is known to reduce the incidence of further ischemic and hemorrhagic events in patients with moyamoya disease, but the majority of previous studies report only short-term (< 5 years) outcomes. Therefore, in this study the authors aimed to evaluate late (5-20 years) outcomes of moyamoya patients after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and indirect bypass (encephalo-duro-myo-arterio-pericranial synangiosis [EDMAPS]).

METHODS

Cumulative incidences of late morbidity/mortality and disease progression were evaluated among 93 patients who underwent STA-MCA anastomosis and EDMAPS. All of the patients were prospectively followed up for longer than 5 years postsurgery (10.5 ± 4.4 years). There were 35 pediatric and 58 adult patients. Initial presentation included transient ischemic attack/ischemic stroke in 80 patients and hemorrhagic stroke in 10 patients, and 3 patients were asymptomatic. Surgery was performed in a total of 141 hemispheres. Follow-up MRI/MRA was performed within a 6- or 12-month interval during the follow-up periods.

RESULTS

During the follow-up periods, 92/93 patients were free from any stroke or death, but 1 patient had a recurrence of hemorrhagic stroke (0.10% per patient-year). Disease progression occurred in the territory of the contralateral carotid or posterior cerebral artery (PCA) in 19 hemispheres of 15 patients (1.5% per patient-year). The interval between initial surgery and disease progression varied widely, from 0.5 to 15 years. Repeat bypass surgery for the anterior and posterior circulation resolved ischemic attacks in all 10 patients.

CONCLUSIONS

The study results indicate that STA-MCA anastomosis and EDMAPS would be the best choice to prevent further ischemic and hemorrhagic stroke for longer than 10 years on the basis of the demonstrated widespread improvement in cerebral hemodynamics in both the MCA and ACA territories in the study patients. However, after 10 years postsurgery regular follow-up is essential to detect disease progression in the territory of the contralateral carotid artery and PCA and prevent late cerebrovascular events.

Surgical revascularization for Moyamoya disease in the United States: A cost-effectiveness analysis

Objective

Moyamoya disease (MMD) is a vasculopathy of the internal carotid arteries with ischemic and hemorrhagic sequelae. Surgical revascularization confers upfront peri-procedural risk and costs in exchange for long-term protective benefit against hemorrhagic disease. The authors present a cost-effectiveness analysis (CEA) of surgical versus non-surgical management of MMD.

Methods

A Markov Model was used to simulate a 41-year-old suffering a transient ischemic attack (TIA) secondary to MMD and now faced with operative versus nonoperative treatment options. Health utilities, costs, and outcome probabilities were obtained from the CEA registry and the published literature. The primary outcome was incremental cost-effectiveness ratio which compared the quality adjusted life years (QALYs) and costs of surgical and nonsurgical treatments. Base-case, one-way sensitivity, two-way sensitivity, and probabilistic sensitivity analyses were performed with a willingness to pay threshold of $50,000.

Results

The base case model yielded 3.81 QALYs with a cost of $99,500 for surgery, and 3.76 QALYs with a cost of $106,500 for nonsurgical management. One-way sensitivity analysis demonstrated the greatest sensitivity in assumptions to cost of surgery and cost of admission for hemorrhagic stroke, and probabilities of stroke with no surgery, stroke after surgery, poor surgical outcome, and death after surgery. Probabilistic sensitivity analyses demonstrated that surgical revascularization was the cost-effective strategy in over 87.4% of simulations.

Conclusions

Considering both direct and indirect costs and the postoperative QALY, surgery is considerably more cost-effective than non-surgical management for adults with MMD.

Ameliorative Effects of Combined Revascularization Surgery on Abnormal Collateral Channels in Moyamoya Disease

OBJECT

Abnormal collateral channels, so-called moyamoya vessels, play a critical role to compensate cerebral ischemia, but carry the risk for hemorrhagic stroke in moyamoya disease (MMD). The present study was aimed to clarify if superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and encephalo-myo-duro-arterio-pericranial synangiosis (EDMAPS) can efficiently regress the abnormal collateral channels in MMD patients.

METHODS

This study included 92 hemispheres of 61 MMD patients who underwent STA-MCA anastomosis combined with EDMAPS between 2013 and 2019. There were 17 children and 44 adults. We retrospectively analyzed the findings on cerebral angiography before and 3 to 6 months after surgery, including Suzuki's angiographical stage, the development of surgical collaterals, and the extent of abnormal collateral channels such as lenticulostriate, thalamic, and choroidal channels.

RESULTS

Following surgery, no pediatric and adult patients experienced any stroke during follow-up periods (40.2±25.5 and 54.9±19.7 months, respectively). Suzuki's stage significantly advanced in both adult and pediatric patients after surgery (P=0.042 and P<0.001). In adult patients, all of the lenticulostriate, thalamic, and choroidal channels significantly regressed after surgery (P<0.001, P=0.012, and P=0.004, respectively). In pediatric patients, however, lenticulostriate and choroidal channels significantly regressed (P=0.005 and P=0.034, respectively). Correlation analysis revealed that the development of surgical collaterals determined the postoperative regression of choroidal channels (P<0.001).

CONCLUSION

STA-MCA anastomosis and EDMAPS may be one of the most effective procedures to widely provide surgical collaterals to the operated hemispheres and prevent not only ischemic but also hemorrhagic stroke by regressing the hemorrhage-prone abnormal collateral channels in MMD.

Limits and pitfalls of indirect revascularization in moyamoya disease and syndrome

Moyamoya vasculopathy is a rare chronic cerebrovascular disorder characterized by the stenosis of the terminal branches of the internal carotid arteries and the proximal tracts of anterior and middle cerebral arteries. Although surgical revascularization does not significantly change the underlying pathogenic mechanisms, it plays a pivotal role in the management of affected individuals, allowing to decrease the risk of ischemic and hemorrhagic complications. Surgical approaches may be direct (extracranial-intracranial bypass), indirect, or a combination of the two. Several indirect techniques classifiable according to the tissue (muscle, periosteum, galea, dura mater, and extracranial tissues) or vessel (artery) used as a source of blood supply are currently available. In this study, we reviewed the pertinent literature and analyzed the advantages, disadvantages, and pitfalls of the most relevant indirect revascularization techniques. We discussed the technical aspects and the therapeutical implications of each procedure, providing a current state-of-the-art overview on the limits and pitfalls of indirect revascularization in the treatment of moyamoya vasculopathy.

Functional Outcomes After Revascularization Procedures in Patients With Hemorrhagic Moyamoya Disease

BACKGROUND

Poor natural history of hemorrhagic Moyamoya disease (MMD) is related to high rehemorrhage rates between 32% and 61%. Postrevascularization, rehemorrhage rates reportedly decrease to 12% to 17%.

OBJECTIVE

To evaluate long-term functional outcomes and rehemorrhage rates of hemorrhagic MMD patients treated with surgical revascularization and examine these in relation to clinical and radiological factors.

METHODS

Patients treated surgically for hemorrhagic MMD over a 26-yr period were identified. Modified Rankin scale (mRS) was used to assess clinical status at presentation and functional outcomes. Multivariable regression analyses were performed to evaluate the risk factors associated with rehemorrhage rates and functional outcomes.

RESULTS

A total of 104 patients (mean age: 38.04 yr) were identified. The mean mRS score at baseline was 1.3. Of 172 revascularized hemispheres, 157 (91.3%) were direct superficial temporal artery (STA)-middle cerebral artery (MCA) bypasses and the rest indirect. Over the mean follow-up of 61.4 mo, 8 of 104 patients (7.7%) experienced rehemorrhage with rehemorrhage rate per person-years of 1.9%. A total of 4 patients died with 1 related to rehemorrhage. At the last follow-up, mean mRS score improved to 1.1. No significant risk factors were identified in relation to the rehemorrhage rates (P < .05). The patients' initial mRS score was positively associated with mRS scores at the final follow-up (P < .001). STA-MCA direct bypass was associated with better performance status (P = .033).

CONCLUSION

Rehemorrhage rate following surgical revascularization of the hemorrhagic MMD patients at 7.7% is lower compared with much higher natural history rates. Surgical revascularization improved patients' performance status. These outcomes support performing revascularization procedure with a preference for direct STA-MCA bypasses.

Complications following Encephalo-Duro-Arterio-Myo-Synangiosis in a case of Moyamoya disease

We report a case of an 18-year-old girl diagnosed to have Moyamoya disease (MMD), who underwent bilateral encephalo-duro-arterio-myo-synangiosis. Literature search has clearly inferred that in comparison to an adult patient, children with MMD can have a good prognosis if early diagnosis and active surgical intervention are achieved. Evidence has demonstrated that active surgical management, including indirect bypass surgery, may improve the cerebral circulation on a relatively larger scale than direct bypass surgeries, which can only improve the cerebral circulation in the area of the vascular reconstruction.

Postoperative collateral formation after indirect bypass for hemorrhagic moyamoya disease

Background

The research on postoperative collateral formation for hemorrhagic moyamoya disease (MMD) evaluated by using digital subtraction angiography (DSA) is limited. Our study objective was to investigate the postoperative collateral formation after indirect bypass for hemorrhagic MMD.

Methods

All consecutive inpatients with hemorrhagic MMD who received indirect bypass at Beijing Tiantan Hospital, Capital Medical University from January 2010 through December 2018 were screened. The site of the hemorrhage was classified as either anterior or posterior. Postoperative collateral formation was evaluated on lateral views using the Matsushima scale. Univariate and multivariate logistic regression analyses were carried out to determine the factors influencing postoperative collateral formation.

Results

Six-four patients (64 hemispheres) were included in this study. After a median 8.5 months DSA follow-up, 14 (21.9%) hemispheres had grade A collateral circulation, 13 (20.3%) had grade B, and 37 (57.8%) had grade C. Twenty-seven (42.2%) hemispheres had good postoperative collateral formation and 37 (57.8%) had poor postoperative collateral formation. The univariate logistic regression analyses showed that age at operation (OR, 0.954; 95% CI, 0.908–1.003; p = 0.066), hemorrhagic site (OR, 4.694; 95% CI, 1.582–13.923; p = 0.005), and PCA involvement (OR, 3.474; 95% CI, 0.922–13.086; p = 0.066) may effect postoperative collateral formation. The multivariate logistic regression analyses showed that only anterior hemorrhage (OR, 5.222; 95% CI, 1.605–16.987; p = 0.006) was significantly related to good postoperative collateral formation.

Conclusion

Anterior hemorrhage was significantly related to good postoperative collateral formation after indirect bypass.

[Modern trends in diagnosis and surgical treatment of moyamoya disease]

This review is devoted to moyamoya disease. It is a rare chronic steno-occlusive cerebrovascular disease. However, moyamoya disease is increasingly diagnosed by neurosurgeons in our country. Unlike atherosclerotic lesions of cerebral arteries, pathogenesis and course of this disease are much more complex and variable. Therefore, specialists often have certain difficulties in diagnosis, management and treatment of these patients. To date, a large number of surgical interventions have been proposed for the treatment of moyamoya disease. Revascularization approaches include direct procedures (extra-intracranial microanastomoses), indirect methods (synangioses) and combined revascularization. The purpose of the review is to systematize current literature data on the pathogenesis, diagnosis, clinical patterns and surgical treatment of patients with moyamoya disease. results Outcomes of surgical revascularization and the role of its various components in combined approach are under particular attention.

Predictors of clinical or cerebral lesion progression in adult moyamoya angiopathy

OBJECTIVE

To identify independent predictors of clinical or cerebral lesion progression in a large sample of adult patients with moyamoya angiopathy (MMA) prior to decisions regarding revascularization surgery.

METHODS

Ninety participants (median age, 37.5 years) were assessed at baseline and followed for a median time of 42.8 months. Incident ischemic and hemorrhagic strokes, death, as well as any incident ischemic and hemorrhagic lesions on MRI were recorded. Multiple demographic, clinical, and cerebral imaging measures at baseline were considered as potential predictors of clinical or cerebral tissue change at follow-up. Data were analyzed based on the Andersen-Gill counting process model, followed by internal validation of the prediction model.

RESULTS

Among multiple potential predictive measures considered in the analysis, Asian origin, a history of TIAs, and a reduction in hemodynamic reserve, as detected by imaging, were found to be significantly associated with an increased risk of combined clinical and imaging events. While the model estimated the risk of clinical or cerebral lesion progression to be approximately 0.5% per year when none of these factors was present, this risk exceeded 20% per year when all factors were present.

CONCLUSION

A simple combination of demographic, clinical, and cerebral perfusion imaging measures may aid in predicting the risk of incident stroke and cerebral lesion progression in adult patients with MMA. These results may help to improve therapeutic decisions and aid in the design of future trials in adults with this rare condition.

Encephaloduroarteriosynangiosis for hemorrhagic moyamoya disease: long-term outcome of a consecutive series of 95 adult patients from a single center

OBJECTIVE

The objective of this study was to investigate long-term outcomes after encephaloduroarteriosynangiosis (EDAS) for the treatment of hemorrhagic moyamoya disease (MMD) and identify the risk factors for recurrent hemorrhages.

METHODS

The authors retrospectively reviewed 95 patients with hemorrhagic MMD who were treated with EDAS at 307th Hospital PLA. Clinical features, angiographic findings, and clinical outcomes were investigated. Rebleeding incidences were compared between anterior or posterior hemorrhagic sites. Kaplan-Meier survival analysis and Cox proportional hazards regression models were used to estimate rebleeding risks after EDAS.

RESULTS

The average age at symptom onset was 37.1 years (range 20-54 years) for adult patients. The ratio of female to male patients was 1.16:1. In 61 of 95 hemorrhagic hemispheres (64.2%), the anterior choroidal artery (AChA) or posterior communicating artery (PCoA) was extremely dilated, with extensive branches beyond the choroidal fissure, which only occurred in 28 of 86 nonhemorrhagic hemispheres (32.6%). Fifty-seven incidences were classified as anterior hemorrhages and 38 as posterior. Sixteen of 95 patients (16.8%) suffered cerebral rebleeding after a median follow-up duration of 8.5 years. The annual rebleeding rate was 2.2% per person per year. The incidence rate was higher for the posterior group than for the anterior group, but this difference was not statistically significant (p > 0.05). Cox regression analysis revealed that the age of symptom onset (OR 1.075, 95% CI 1.008-1.147, p = 0.028) was a predictor of rebleeding strokes.

CONCLUSIONS

Through long-term follow up, EDAS proved beneficial for patients with hemorrhagic MMD. Dilation of the AChA-PCoA is associated with the initial hemorrhage of MMD, and rebleeding is age-related. Patients with hemorrhagic MMD should undergo follow-up over the course of their lives, even when neurological status is excellent.

Differing Surgical Outcomes in a Multiethnic Cohort Suggest Racial Phenotypes in Moyamoya Disease

BACKGROUND

Variable Moyamoya disease (MMD) genotypes and phenotypes between different races have been suggested previously. This study investigates differences in surgical complications and response to revascularization among Asian patients with MMD compared with other ethnicities in North America.

METHODS

From a database of 185 patients with moyamoya presenting to our institution between 1994 and 2015, 85 patients with MMD underwent surgery and constituted the study cohort. Baseline characteristics before surgery, procedure-related complications, length of hospital stay, and outcome variables including stroke and functional outcome were compared between Asian and non-Asian patients. Kaplan-Meier survival analyses were used to compare time to ipsilateral stroke and any cerebrovascular event after bypass.

RESULTS

Our surgical cohort consisted of 27% (23/85) Asian and 73% (62/85) non-Asian patients with MMD with a bimodal age distribution. Among the subset of patients who presented with stroke (n = 55), hemorrhage was significantly more common among Asian patients (P = 0.007). In 120 revascularization procedures, per-operative complication rates were greater among Asian patients while controlling for age, type of surgery, and stroke history (odds ratio 2.94; 95% confidence interval 1.16-7.48; P = 0.02). The mean follow-up time after surgery was 4.57 years. Ipsilateral cerebrovascular event rates were 4.77 per 100 person-years in non-Asian patients and 6.51 per 100 person-years in Asians (P = 0.66). Unfavorable modified Rankin Scale scores (>2) were found in 22% of Asian patients and 8% of non-Asian patients on last follow-up (P = 0.13).

CONCLUSIONS

Asian patients with MMD may be more susceptible to surgical complications and may differ from other races in their response to revascularization. Further long-term prospective studies are needed to investigate these findings.

Restoration of periventricular vasculature after direct bypass for moyamoya disease: intra-individual comparison

BACKGROUND

While periventricular anastomosis, a unique abnormal vasculature in moyamoya disease, has been studied in relation to intracranial hemorrhage, no study has addressed its change after bypass surgery. The authors sought to test whether direct bypass surgery could restore normal periventricular vasculature.

METHODS

Patients who had undergone direct bypass surgery for moyamoya disease at a single institution were eligible for the study. Baseline, postoperative, and follow-up magnetic resonance angiography (MRA) scans were scheduled before surgery, after the first surgery, and 3 to 6 months after contralateral second surgery, respectively. Sliding-thin-slab maximum-intensity-projection coronal MRA images of periventricular anastomoses were scored according to the three subtypes (lenticulostriate, thalamic, and choroidal anastomosis). Baseline and postoperative MRA images were compared to obtain a matched comparison of score changes in the surgical and nonsurgical hemispheres within individuals (intra-individual comparison).

RESULTS

Of 110 patients, 42 were identified for intra-individual comparisons. The periventricular anastomosis score decreased significantly in the surgical hemispheres (median, 2 versus 1; p < 0.001), whereas the score remained unchanged in the nonsurgical hemispheres (median, 2 versus 2; p = 0.57); the score change varied significantly between the surgical and nonsurgical hemispheres (p < 0.001). Of the 104 periventricular-anastomosis-positive hemispheres undergoing surgery, 47 (45.2%) were assessed as negative in the follow-up MRA. Among the subtypes, choroidal anastomosis was most likely to be assessed as negative (79.7% of positive hemispheres).

CONCLUSIONS

Periventricular vasculature can be restored after direct bypass. The likelihood of correction of choroidal anastomosis is a subject requiring further studies.

A Comprehensive Meta-Analysis for Bypass Surgery in Adult Moyamoya

OBJECTIVE

To evaluate the outcomes of bypass surgery for adult moyamoya and compare different surgical modalities by performing a comprehensive meta-analysis of relevant studies.

METHODS

A systematic literature search was performed and articles regarding different treatments for adult patients with moyamoya were included. Odds ratios (ORs) were calculated to evaluate stroke recurrence, mortality, perioperative complications, and angiographic revascularization among different surgical methods and conservative treatment (CT).

RESULTS

A total of 17 studies with 2224 adult patients with moyamoya were included in the meta-analysis. Compared with CT, surgical revascularization significantly decreased the future stroke events in the total population ([OR] 0.404; 95% confidence interval [CI] 0.279-0.585; P < 0.001) and in the hemorrhagic-onset patients as well (OR 0.259; 95% CI 0.138-0.486; P < 0.001). However, for those patients with moyamoya and ischemia, there was no significant difference for future stroke events between the bypass and CT groups (OR 0.470; 95% CI 0.140-1.579; P = 0.222). Bypass also showed no mortality reduction compared with CT (OR 0.372; 95% CI 0.120-1.154; P = 0.087). For different surgical techniques, no differences for future stroke events, mortality, and perioperative complications were found between direct bypass and indirect bypass, whereas the degree of angiographic revascularization was better in the direct bypass group than in the indirect group (OR 4.720; 95% CI 1.222-18.230; P = 0.024).

CONCLUSIONS

The bypass treatment was superior to conservative treatment in preventing recurrent stroke in adult patients with moyamoya, especially in those with a hemorrhagic onset. Direct bypass is associated with better revascularization results compared with indirect bypass.

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.

Time Course of Neoangiogenesis After Indirect Bypass Surgery for Moyamoya Disease : Comparison of Short-term and Long-term Follow-up Angiography

OBJECTIVE

Indirect bypass surgery, which induces spontaneous neoangiogenesis in ischemic brain tissue and improves cerebral blood flow, is an effective treatment for moyamoya disease (MMD). The time course of neoangiogenesis development has not yet been investigated. This study aimed to determine the critical period of neovascularization after indirect bypass in MMD patients.

METHODS

Patients with MMD who underwent indirect bypass surgery at Peking University International Hospital between January 2015 and October 2017 were retrospectively reviewed. Surgically treated hemispheres with short-term (3-6 months) and long-term (1 year) follow-up digital subtraction angiography (DSA) were included. The effects of revascularization were evaluated on lateral and anteroposterior views using angiography and compared between two follow-ups of the same hemisphere.

RESULTS

This study included 25 hemispheres from 24 MMD patients (mean age: 22.48 ± 14.83 years), among whom 13 were pediatric patients and 12 were adults. Qualitative measurements including the Matsushima scale and coverage of neoangiogenesis on anteroposterior views were not significantly different between the short term and long term (P = 0.083 and P = 0.157, respectively). Quantitative measurements including the greatest width and height of the area covered by neovascularization on lateral views of DSA and the greatest depth of neovascularization penetration on anteroposterior views (P = 0.488, 0.298 and 0.527, respectively) were also not significantly different. The mean count of newly formed veins was more at long-term than short-term follow-up (5.5 ± 2.5 vs. 5.1 ± 2.4, P = 0.005). Subgroup analysis of pediatric patients and adults yielded the same results as in the whole series.

CONCLUSION

After indirect bypass surgery, the major time window of arterial neoangiogenesis development was within 6 months after surgery. The general effect of revascularization was very similar in the short and long term; therefore, a follow-up angiography scheduled at 6 months after surgery is recommended. Growth of veins might continue after 6 months.

Novel Indirect Revascularization Technique with Preservation of Temporal Muscle Function for Moyamoya Disease Encephalo-Duro-Fascio-Arterio-Pericranial-Synangiosis: A Case Series and Technical Note

BACKGROUND

Direct and/or indirect bypass surgery is the established approach for preventing stroke in patients with moyamoya disease. However, conventional indirect revascularization, including encephalo-myo-synangiosis, has some disadvantages associated with the mass effect of the temporal muscle under the bone flap and postsurgical depression in the temporal region. We devised a novel indirect revascularization method, using only the temporal fascia, to address the aforementioned disadvantages.

METHODS

A skin incision was performed along the superficial temporal artery. The temporal fascia was cut such that the base of the fascia flap was on the posterior side. The fascia and temporal muscles were dissected separately. After turning over the fascia, the muscle was cut such that the base of the muscle flap was on the anterior side. Craniotomy, direct bypass, and encephalo-duro-synangiosis were performed conventionally. Only the temporal fascia was used for indirect revascularization and duraplasty. The muscle was replaced in the anatomically correct position after replacing the bone flap.

RESULTS

We performed the aforementioned surgery on 18 (13 women and 5 men) consecutive patients (21 cerebral hemispheres) enrolled between 2012 and 2016. The average age was 28.7 years. The mean follow-up period was 31.6 months. In 17 patients (94%), the symptoms and cerebral blood flow improved. Digital subtraction angiography showed satisfactory angiogenesis from the temporal fascia. Depression in the temporal region and atrophy of the temporal muscle were negligible.

CONCLUSIONS

This surgical technique provides good clinical and cosmetic outcomes. It may also be one of the good surgical treatments available for symptomatic moyamoya disease.

Long-term Outcomes After Encephaloduroarteriosynangiosis in Adult Patients with Moyamoya Disease Presenting with Ischemia

BACKGROUND

In adult Moyamoya disease (MMD), there remains controversy about the effectiveness of revascularization surgeries because randomized studies have not been performed to compare the efficacy of surgical techniques. This study was conducted to assess the most appropriate surgical treatment for adult patients with MMD.

METHODS

Encephaloduroarteriosynangiosis (EDAS) was performed on 247 hemispheres in 145 patients. The clinical and demographic characteristics of patients were obtained via retrospective chart review. Clinical and angiographic states were evaluated retrospectively using quantitative methods. The mean duration of clinical follow up was 141.4 ± 19.5 months.

RESULTS

A total of 247 EDAS procedures were performed in 145 patients, including 15 EDAS performed using the occipital artery as the donor vessel. The mortality rate was 0%, and the permanent morbidity rates were 1.2% per operation and 2.0% per person. The mean modified Rankin Scale score was 1.21 ± 1.31 postoperatively and 1.01 ± 1.39 at the last follow-up. Of the 109 hemispheres studied, 45% were classified as grade A, 34% as grade B, and 21% as grade C collateral circulation. The annual rates of stroke were calculated to be 0.73% per person-year. Overall, the 1-,5-, and 10-year actuarial stroke rates were 2.1±1.2%, 6.8±2.1%, and 8.9±2.4%, respectively. Bilateral involvement was a common significant factor in any, hemorrhagic, and ischemic strokes. Hypertension was a risk factor for ischemic strokes during follow-up.

CONCLUSIONS

EDAS is an effective procedure in a Chinese cohort of patients with MMD. EDAS resulted in satisfactory long-term improvement of clinical states and prevention of recurrent strokes.

Safety of Extracranial-Intracranial Arterial Bypass in the Treatment of Moyamoya Disease

OBJECTIVE

The purpose of this study is to uncover the controversial problems and review the safety of extracranial-intracranial arterial bypass (EC-IC arterial bypass) in the treatment of moyamoya disease.

METHODS

Published randomized controlled clinical trials were searched from PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Web of science without date or language limitations until September 2016. Meta-analysis was performed as recommended by the Cochrane Collaboration of trials.

RESULTS

In total 2 studies were included by strict inclusion and exclusion criteria. The result of meta-analysis showed that surgical group had a greater reduction of the primary end points (OR [0.35], 95% CI [0.15, 0.84], I = 0%) than that of the nonsurgical group.

CONCLUSION

Surgical therapy significantly lowers incidence of the primary end points (including rebleeding attack; completed stroke resulting in significant morbidity; mortality from any medical cause and requirement for bypass surgery fora nonsurgical patient as determined by a registered neurologist) compared with nonsurgical therapy. High-quality randomized controlled trials are required to confirm this conclusion.

Clinical Features, Surgical Treatment, and Long-Term Outcome in Children with Hemorrhagic Moyamoya Disease

BACKGROUND

The objective of this study was to elucidate the clinical features, surgical treatment, and long-term outcome in pediatric patients with moyamoya disease (MMD).

METHODS

We retrospectively reviewed 46 pediatric patients with hemorrhagic MMD at Beijing Tiantan Hospital. Clinical features, radiological findings, and outcomes were analyzed.

RESULTS

The mean age at diagnosis was 13.6 ± 3.6 years. The ratio of girls to boys was 1.0:1.1. Familial occurrence was 4.3%. The primary symptoms at initial presentation were intraventricular hemorrhage (IVH) (47.8%), intracerebral hemorrhage (ICH) (37.0%), ICH with IVH (13.0%), and subarachnoid hemorrhage (2.2%). Most patients presented with Suzuki stage 3 or 4 MMD. Posterior cerebral artery involvement was observed in 22 (18.4%) patients. During the average follow-up of 126.1 ± 96.0 months, 11 of 53 (20.8%) conservatively treated hemispheres and 1 of 36 (2.8%) surgically treated hemispheres experienced a stroke event (P < .05). There was a difference in the Kaplan-Meier curve of stroke between the 2 groups (log rank test, P < .05). What is more, the rate of perfusion improvement in surgically treated patients was higher than in those conservatively treated patients 3 months after discharge (P < .05).

CONCLUSIONS

Revascularization surgery has a role in the prevention of recurrent strokes and can improve cerebral perfusion in pediatric patients with hemorrhagic MMD. Further study is needed to determine which bypass surgery is more beneficial for pediatric patients with hemorrhagic MMD.

Clinical analysis of combined revascularization in treating ischemic Moyamoya disease in adults

OBJECTIVE

The aim of this study was to investigate the clinical efficacy of superficial temporal artery-middle cerebral artery anastomosis (STA-MCA)+encephalo-duro-myo-synangiosis (EDMS) in treating ischemic Moyamoya disease (IMD) in adults.

METHODS

A total of 30 adult patients with IMD were selected to be included in the study; they underwent STA-MCA+EDMS and were followed up for 3 months to 2 years. The digital subtraction angiography findings, modified Rankin scale (mRs) score, and complications of all the patients were compared.

RESULTS

Thirty patients successfully completed the surgery. Three patients had postoperative complications (two patients with cerebral infarction on the surgical side and one patient with poor scalp healing). The postoperative morbidity rate was 10%. Angiography conducted at 3 to 6 months postoperatively showed 28 cases of anastomotic patency; the anastomotic patency rate was 93.3%. The mRs scores of the patients' neurological function 3 months after surgery were lower than those before surgery.

CONCLUSION

STA-MCA+EDMS is effective in treating Moyamoya disease.

Quantitative assessment of changes in hemodynamics of the internal carotid artery after bypass surgery for moyamoya disease

OBJECTIVE Although intracranial vessel remodeling has been observed in moyamoya disease, concerns remain regarding the effect of bypass surgery on hemodynamic changes within the internal carotid artery (ICA). The authors aimed to quantify the surgical effect of bypass surgery on bilateral ICAs in moyamoya disease and to estimate pressure drop (PD) along the length of the ICA to predict surgical outcomes. METHODS Records of patients who underwent bypass surgery for treatment of moyamoya disease and in whom flow rates were obtained pre- and postsurgery by quantitative MR angiography were retrospectively reviewed. Quantitative MR angiography and computational fluid dynamics were applied to measure morphological and hemodynamic changes during pre- and postbypass procedures. The results for vessel diameter, volumetric flow, PD, and mean wall shear stress along the length of the ICA were analyzed. Subgroup analysis was performed for the circle of Willis (CoW) configurations. RESULTS Twenty-three patients were included. The PD in ICAs on the surgical side (surgical ICAs) decreased by 21.18% (SD ± 30.1%) and increased by 11.75% (SD ± 28.6%) in ICAs on the nonsurgical side (contralateral ICAs) (p = 0.001). When the PD in contralateral ICAs was compared between patients with a complete or incomplete CoW, the authors found that the PDI in the former group decreased by 2.45% and increased by 20.88% in the latter (p = 0.05). Regression tests revealed that a greater postoperative decrease in PD corresponded to shrinking of ICAs (R² = 0.22, p = 0.02). CONCLUSIONS PD may be used as a reliable biomechanical indicator for the assessment of surgical treatment outcomes. The vessel remodeling characteristics of contralateral ICA were related to CoW configurations.

Chronologic Evaluation of Cerebral Hemodynamics by Dynamic Susceptibility Contrast Magnetic Resonance Imaging After Indirect Bypass Surgery for Moyamoya Disease

OBJECTIVE

Although indirect bypass surgery is an effective treatment option for patients with ischemic-onset moyamoya disease (MMD), the time point after surgery at which the patient's hemodynamic status starts to improve and the time point at which the improvement reaches a maximum have not been known. The objective of the present study is to evaluate the hemodynamic status time course after indirect bypass surgery for MMD, using dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI).

METHODS

We retrospectively analyzed the cases of 25 patients with MMD (37 sides; mean age, 14.7 years; range, 3-36 years) who underwent indirect bypass surgery and repeated DSC-MRI measurement within 6 months after the operation. The difference in the mean transit time (MTT) between the target regions and the control region (cerebellum) was termed the MTT delay, and we measured the MTT delay's chronologic changes after surgery.

RESULTS

The postoperative MTT delay was 1.81 ± 1.16 seconds within 1 week after surgery, 1.57 ± 1.01 at weeks 1-2, 1.55 ± 0.68 at weeks 2-4, 1.32 ± 0.68 at months 1-2, 0.95 ± 0.32 at months 2-3, and 0.77 ± 0.33 at months 3-6. Compared with the preoperative value (2.11 ± 0.98 seconds), the MTT delay decreased significantly from 2 to 4 weeks after surgery (P < 0.05).

CONCLUSIONS

The amelioration of cerebral hemodynamics by indirect bypass surgery began soon after surgery and gradually reached a maximum at 3 months after surgery. DSC-MRI detected small changes in hemodynamic improvement, which are suspected to be caused by the initiation of angiogenesis and arteriogenesis in the early postoperative period.

Bypass surgery versus medical treatment for symptomatic moyamoya disease in adults

OBJECTIVE

In this study the authors evaluated whether extracranial-intracranial bypass surgery can prevent stroke occurrence and decrease mortality in adult patients with symptomatic moyamoya disease (MMD).

METHODS

The medical records of 249 consecutive adult patients with symptomatic MMD that was confirmed by digital subtraction angiography between 2002 and 2011 at 8 institutions were retrospectively reviewed. The study outcomes of stroke recurrence as a primary event and death during the 6-year follow-up and perioperative complications within 30 days as secondary events were compared between the bypass and medical treatment groups.

RESULTS

The bypass group comprised 158 (63.5%) patients, and the medical treatment group comprised 91 (36.5%) patients. For 249 adult patients with MMD, bypass surgery showed an HR of 0.48 (95% CI 0.27–0.86, p = 0.014) for stroke recurrence calculated by Cox regression analysis. However, for the 153 patients with ischemic MMD, the HR of bypass surgery for stroke recurrence was 1.07 (95% CI 0.43–2.66, p = 0.887). For the 96 patients with hemorrhagic MMD, the multivariable adjusted HR of bypass surgery for stroke recurrence was 0.18 (95% CI 0.06–0.49, p = 0.001). For the treatment modality, indirect bypass and direct bypass (or combined bypass) did not show any significant difference for stroke recurrence, perioperative stroke, or mortality (log rank; p = 0.524, p = 0.828, and p = 0.616, respectively).

CONCLUSIONS

During the treatment of symptomatic MMD in adults, bypass surgery reduces stroke recurrence for the hemorrhagic type, but it does not do so for the ischemic type. The best choice of bypass methods in adult patients with MMD is uncertain. In adult ischemic MMD, a prospective randomized study to evaluate the effectiveness and safety of bypass surgery to prevent recurrent stroke is necessary.

Moyamoya Disease Emerged with Corpus Callosum Hemorrhage: A 3D Computer Graphic Analysis

The authors present a rare case of moyamoya disease emerged with corpus callosum hemorrhage. A 31-year-old woman suddenly complained of severe headache followed by consciousness disturbance. Radiological examinations revealed the bleeding in the splenium of corpus callosum, which was associated with intraventricular hemorrhage. On cerebral angiography, the carotid fork was severely stenotic on both sides, and a marked dilatation was observed in the anterior/posterior choroidal arteries and posterior pericallosal artery as well as the lenticulostriate arteries. Therefore, she was diagnosed as moyamoya disease. She successfully underwent superficial temporal artery to middle cerebral artery (STA–MCA) anastomosis and indirect bypass on both sides. Postoperative course was uneventful. Follow-up cerebral angiography performed 4 months after surgery showed well-developed surgical collaterals via the external carotid system and a marked decrease of the dilated moyamoya vessels. She has been free from any cerebrovascular events for 36 months after surgery. Radiological findings strongly suggest that splenial bleeding occurred due to the rupture of the dilated abnormal collateral vessels that originate from the medial posterior choroidal artery and penetrate the corpus callosum in this case. Three-dimensional computer graphic analysis was useful to determine the complex collateral circulation in moyamoya disease.

Acceleration of blood flow as an indicator of improved hemodynamics after indirect bypass surgery in Moyamoya disease

OBJECTIVE

The ultrasonography findings in the superficial temporal artery (STA) in Moyamoya disease patients treated with indirect bypass remain unclear. We evaluated the time-related changes in ultrasonography findings of the STA main trunk and branches in patients with Moyamoya disease who underwent encephalo-duro-arterio-synangiosis (EDAS).

PATIENTS AND METHODS

Patients (n=21, 30 sides) with Moyamoya disease who underwent EDAS at Fukuoka University Hospital were prospectively registered between 2008 and 2015. EDAS using the frontal and parietal branches of the STA was adopted in an indirect bypass procedure. Mean velocity (MV) and resistance index (RI) were used as ultrasonography markers, and their changes over time in the STA main trunk and branches were assessed.

RESULTS

There was a significant increase in MV in both the STA main trunk (p=0.001) and branches (frontal: p=0.005, parietal: p=0.003) at 3 months after EDAS, whereas there was a decrease in RI at 14days after EDAS (main trunk: p <0.001, frontal: p <0.001, parietal: p=0.014). In subgroup analysis of patients divided by EDAS outcome, compared with before EDAS, there were significant differences at 3 months after EDAS in MV (responders: main trunk: p=0.002, frontal: p=0.001, parietal: p=0.001; non-responders: main trunk: p=0.093, frontal: p=0.24, parietal: p=0.96) and RI (responders: main trunk: p<0.001, frontal: p<0.001, parietal: p=0.006; non-responders: main trunk: p=0.17, frontal: p=0.12, parietal: p=0.17).

CONCLUSIONS

Measurement of MV may be useful for predicting outcome at 3 months after EDAS.

Moore J, Adeeb N, Griessenauer CJ, Patel AS, Chua MH, Thomas AJ, Ogilvy CS. Clinical presentation, progression, and treatment outcomes of moyamoya disease in the elderly

BACKGROUND

Moyamoya disease is a vascular disorder characterized by progressive stenosis of the internal carotid artery. The presentation, progression, treatment options, and post-operative clinical outcomes for elderly (60 and older) Moyamoya patients have never been reported.

METHODS

A retrospective analysis of all patients who were diagnosed with Moyamoya disease by the senior authors between 1991 and 2016 was performed. Patients who were 60 years or older at the time of surgery or last follow-up were further evaluated.

RESULTS

Seventy patients were diagnosed with probable or definite Moyamoya disease during the study period (1991-2016). Eight patients (11.4 %; six females: two males; median age 63; range, 60-71 years) were found to be 60 years or older at the time of surgery or last follow-up and were included in the study. All patients had a modified Rankin scale (mRS) of either one or two (median 1) pre-operatively. Six patients (75 %) underwent surgical treatment on a total on seven hemispheres. Post-surgery, one patient had an improved mRS score, three had no changes, and two had worsening in their mRS scores. Both patients who did not undergo surgical interventions suffered from intra-parenchymal hemorrhages post-diagnosis.

CONCLUSIONS

Moyamoya disease is most commonly seen in young and middle-aged patients. Presentation in the elderly (defined as 60 years and older in this study) is rare, and has never been reported in the literature. In this study, both direct and indirect revascularization procedures demonstrated potential benefit in some of these patients, with stabilization of progressive symptoms.

Surgical Outcome for Moyamoya Disease: Clinical and Perfusion Computed Tomography Correlation

OBJECTIVES

To compare surgical outcome both radiologically and clinically after interventions for patients with Moyamoya disease.

METHODS

This retrospective observational study included 25 patients who were treated surgically for Moyamoya disease in the past 14 years. Clinical outcomes were analyzed by subgroups stratified by age, disease presentation, and surgical intervention. Serial postoperative brain computed tomography perfusion records were analyzed with respect to the cerebral blood flow and cerebrovascular reserve capacity (CVRC) of the middle cerebral artery territory. Changes in both the intervention (n = 23) and nonintervtion (n = 9) cerebral hemispheres were compared.

RESULTS

All children treated by synangiosis (n = 9), all adults receiving synangiosis (n = 5), and 88.9% of adults undergoing bypass (n = 9) had no neurologic deterioration, with a duration of at least 50.6 months, 85.7 months, and 27.7 months, respectively. Radiologically, CVRC improved more markedly after bypass surgery than synangiosis, particularly 12-24 months postoperatively (51.1% vs. -2.86%). The hemispheres that did not undergo intervention showed similar improvement in cerebral blood flow over time compared with the hemispheres that did undergo intervention, after surgery was performed.

CONCLUSIONS

Bypass surgery improved CVRC greater than synangiosis, which may correlate with decreased future stroke risks. The decision for bypass is to be balanced with a greater risk of postoperative neurologic deterioration in adults after this procedure. The hemisphere that did not undergo intervention also appeared to benefit from surgery performed on the contralateral brain.