Strategies for and Outcome of Repeat Revascularization Surgery for Moyamoya Disease: An American Institutional Series

Characterization of Global Research Trends and Prospects on Moyamoya Disease: Bibliometric Analysis

BACKGROUND

Moyamoya disease (MMD) is a rare cerebrovascular disease in neurology. This study investigates the literature related to MMD from its discovery to the present and identifies research levels, achievements, and trends.

METHODS

All publications on MMD from its discovery to present were downloaded from the Web of Science Core Collection on September 15, 2022 and bibliometric analyses were visualized by HistCite Pro, VOSviewer, Scimago Graphica, CiteSpace, and R language.

RESULTS

There were 3414 articles in 680 journals by 10,522 authors in 2441 institutions and 74 countries/regions worldwise are included in the analyses. Since the discovery of MMD, output of publications has shown an upward trend. Japan, the United States, China, and South Korea are 4 major countries in MMD. The United States has the strongest cooperation with other countries. China's Capital Medical University is the output-leading institution worldwide, followed by Seoul National University and Tohoku University. The 3 authors with the most published articles are Kiyohiro Houkin, Dong Zhang, and Satoshi Kuroda. World Neurosurgery, Neurosurgery, and Stroke are the most recognized journals for researchers. Hemorrhagic moyamoya disease, susceptibility gene, and arterial spin are the primary focus areas of MMD research. "Rnf213,""vascular disorder," and "progress" are the top keywords.

CONCLUSIONS

We analyzed publications of global scientific research on MMD systematically by bibliometric methods. This study can provide one of the most comprehensive and accurate analyses for MMD scholars worldwide.

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.

"Recycling" a failed superficial temporal artery indirect bypass into a double barrel direct bypass in moyamoya disease

OBJECTIVES

Moyamoya disease is an idiopathic cerebrovascular disorder in which patients experience recurrent transient ischemic attacks, ischemic or hemorrhagic strokes, headaches, and seizures from progressive stenosis of the vessels of the anterior circulation. The mainstay of treatment in symptomatic patients is surgical revascularization. Here, we present the case of a moyamoya patient in which a failed encephaloduroarteriosynangiosis, after new strokes, is recycled and converted into a combined "double barrel" direct superficial temporal artery to middle cerebral artery bypass with included video.

CASE REPORT/RESULTS

We describe a 37-year-old woman with a history of hypertension, obstructive sleep apnea, celiac disease, and moyamoya disease complicated by multiple ischemic strokes who presented with progressive dysarthria, dysphagia, and new left-sided ischemic infarcts. The patient had previously undergone right-sided direct bypass and left-sided encephaloduroarteriosynangiosis in the setting of multiple ischemic strokes. After more strokes, the patient underwent a left-sided frontotemporoparietal craniotomy for conversion of the failed indirect bypass into a "double barrel" direct bypass.

CONCLUSIONS

The literature is divided over which revascularization procedure should be preferred. Irrespectively, most failed bypass grafts are repaired via direct bypasses, to good effect. We highlight a case in which a failed indirect bypass is directly incorporated into a combined direct bypass with resulting restoration of blood flow. In the case of a failed indirect bypass in an adult patient with moyamoya disease, this method provides the operator with an additional option for restoration of perfusion, especially in patients without other viable vessels available for anastomosis.

Minimally invasive cerebral revascularization in moyamoya disease in adult patients

BACKGROUND

Moyamoya disease (MMD) affects young patients, is generally progressive, and results in strokes or cerebral hemorrhages for which medical management is not effective.

OBJECTIVE

To determine the effectiveness of surgical management with minimally invasive cerebral revascularization in MMD.

MATERIAL AND METHODS

We conducted a retrospective cohort study of patients undergoing extracranial-intracranial microsurgical revascularization surgery with mini-craniotomy, analyzing the epidemiological, clinical, neuroimaging, postoperative evolution, and complications. We describe the technique in detail. Key outcomes included graft patency, complications, and recurrence of ischemic or hemorrhagic stroke.

RESULTS

From September 2017 to December 2020, 12 brain revascularization procedures for MMD were performed in eight patients (four bilateral), and all 12 grafts were classified as patent. The main complication was contralateral cerebral infarction identified by postoperative neuroimaging in a patient without clinical symptomatology. There was no case of scalp ischemia or necrosis when performing the minimally invasive approach with linear incision.

CONCLUSIONS

The results of this study suggest that the minimally invasive extracranial-intracranial cerebral revascularization procedure for MMD in adults is effective, with graft patency in all cases and minimal morbidity.

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.

Salvage multiple burr hole surgery in patients with Moyamoya disease: efficacy evaluation using probabilistic independent component analysis of dynamic susceptibility contrast perfusion MRI

PURPOSE

Multiple burr hole surgery is considered to be an option for achieving indirect revascularization in patients with ischemic Moyamoya disease (MMD). We aimed to investigate the efficacy of stand-alone multiple burr hole surgery for salvage revascularization in patients with MMD by assessing the hemodynamic changes via normalized time-to-peak (nTTP) analysis and independent component analysis (ICA) of preoperative and postoperative dynamic susceptibility contrast (DSC) perfusion MRI data.

METHODS

The DSC perfusion MRI data of 25 hemispheres from 21 patients with MMD, who underwent multiple burr hole surgery for salvage revascularization due to persistent or recurrent symptoms after primary revascularization with modified encephaloduroarteriosynangiosis (mEDAS), were analyzed. The nTTP, which was measured using the region of interests covering the entire surgical hemisphere, was compared between the preoperative and postoperative images. ICA was used to compare the relative arterial and venous components of the surgical hemispheres between the respective preoperative and postoperative images.

RESULTS

The median postoperative nTTP (1.80 s) was significantly shorter than the median preoperative nTTP (4.10 s) (P < 0.001). The postoperative relative arterial component of the surgical hemisphere (median: 0.04) was significantly higher than the preoperative relative arterial component (median: - 0.02, P < 0.001). In contrast, the postoperative relative venous component of the surgical hemisphere (median: - 0.05) was significantly lower than the preoperative value (median: 0.05, P < 0.001).

CONCLUSION

The improvement in cerebral perfusion parameters observed on postoperative DSC perfusion MRI demonstrated that stand-alone multiple burr hole surgery could be a favorable salvage revascularization technique after mEDAS failure in patients with ischemic MMD.

The Genetic Basis of Moyamoya Disease

Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by progressive spontaneous bilateral occlusion of the intracranial internal cerebral arteries (ICA) and their major branches with compensatory capillary collaterals resembling a “puff of smoke” (Japanese: Moyamoya) on cerebral angiography. These pathological alterations of the vessels are called Moyamoya arteriopathy or vasculopathy and a further distinction is made between primary and secondary MMD. Clinical presentation depends on age and population, with hemorrhage and ischemic infarcts in particular leading to severe neurological dysfunction or even death. Although the diagnostic suspicion can be posed by MRA or CTA, cerebral angiography is mandatory for diagnostic confirmation. Since no therapy to limit the stenotic lesions or the development of a collateral network is available, the only treatment established so far is surgical revascularization. The pathophysiology still remains unknown. Due to the early age of onset, familial cases and the variable incidence rate between different ethnic groups, the focus was put on genetic aspects early on. Several genetic risk loci as well as individual risk genes have been reported; however, few of them could be replicated in independent series. Linkage studies revealed linkage to the 17q25 locus. Multiple studies on the association of SNPs and MMD have been conducted, mainly focussing on the endothelium, smooth muscle cells, cytokines and growth factors. A variant of the RNF213 gene was shown to be strongly associated with MMD with a founder effect in the East Asian population. Although it is unknown how mutations in the RNF213 gene, encoding for a ubiquitously expressed 591 kDa cytosolic protein, lead to clinical features of MMD, RNF213 has been confirmed as a susceptibility gene in several studies with a gene dosage-dependent clinical phenotype, allowing preventive screening and possibly the  development of new therapeutic approaches. This review focuses on the genetic basis of primary MMD only.

Surgical Management of Failed Revascularization in Moyamoya Vasculopathy

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

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

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

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

Ipsilateral late stroke after revascularization surgery for patients with Moyamoya disease

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL TRIAL REGISTRATION

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

Current Surgical Options for Moyamoya Disease

Moyamoya disease (MMD) is a cerebrovascular disease of unknown etiology characterized by stenotic and occlusive arterial changes of the anterior circulation, with subsequent proliferative development of arterial collateralization. In spite of there being limited understanding of the clear etiology of MMD, surgical revascularization for MMD is considered the standard treatment to prevent further stroke. While the use of surgical revascularization to prevent future hemorrhagic stroke in MMD is still controversial, it is considered effective in the case of ischemic stroke. This article presents a review of the current surgical management of MMD based on an analysis of the most recent data from peer-reviewed articles and opinion based on personal experience with surgical revascularization in the treatment of MMD.

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.

[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.

Assessment of Single-Barrel Superficial Temporal Artery-Middle Cerebral Artery Bypass in Treatment for Adult Patients with Ischemic-Type Moyamoya Disease

BACKGROUND Moyamoya disease (MMD) is an idiopathic disease caused by progressive steno-occlusion of the distal internal carotid artery. Ideal surgical treatment for adult patients with ischemic-type MMD has not been achieved. The aim of this study was to evaluate the efficacy of single-barrel superficial temporal artery-middle cerebral artery (STA-MCA) bypass in treatment for adult patients with ischemic-type MMD by analyzing clinical and radiological data retrospectively. MATERIAL AND METHODS The present study included 37 patients with non-hemorrhagic MMD, including 21 women and 16 men (21~55 years old, mean age 38.1 years). The bypass surgery was performed on 56 sides in the 37 patients. The clinical charts, angiographic revascularization, and hemodynamic changes were reviewed at 6-60 months after surgery. RESULTS Among the 37 patients, the clinical symptoms and signs of 32 patients were improved or stabilized. Five patients had complications, including 2 cases of acute cerebral infarction, 1 case of epidural hematoma, and 1 case of transient speech disturbance, and 1 patient died. Follow-up computed tomography perfusion (CTP) revealed that cerebral blood flow (CBF) was markedly improved after surgery (P<0.05). Time to peek (TTP) and mean transit time (MTT) were significantly decreased after surgery (P<0.05). No significant change in cerebral blood volume (CBV) was found after surgery (P>0.05). Postoperative patency was clearly verified in 52 bypasses (92.8%) of 56 bypasses on follow-up DSA imaging. CONCLUSIONS Single-barrel STA-MCA bypass can be considered as an effective surgical treatment, which exhibits satisfactory clinical efficacy in ischemic-type MMD patients.