Grading of moyamoya disease allows stratification for postoperative ischemia in bilateral revascularization surgery

Incidence and Outcomes of Posterior Circulation Involvement in Moyamoya Disease

BACKGROUND

Moyamoya disease (MMD) is a progressive, occlusive disease of the internal carotid arteries and their proximal branches, with the subsequent development of an abnormal vascular network that is rupture-prone. Steno-occlusive changes in the posterior cerebral arteries (PCAs) may contribute to worsened outcomes in patients with MMD; however, there is little information on the incidence and natural history of posterior circulation MMD (PCMMD). We describe clinical PCMMD characteristics in a large cohort of patients with MMD.

METHODS

We retrospectively reviewed patients with MMD treated between 1991 and 2019 at a large academic medical center. Demographics, perioperative outcomes, and radiological phenotypes were recorded for 770 patients. PCA disease was graded as either 0 (no disease), 1 (mild), 2 (moderate), or 3 (severe or occluded) based on cerebral angiography. Patients with angiographically confirmed MMD diagnosis with at least 6 months follow-up and completion of revascularization surgery were included; patients with intracranial atherosclerosis, intracranial dissection, vasculitis, and undefined inflammatory processes were excluded. The presence of stenosis/occlusion was graded radiographically to assess for disease progression and the prevalence of risk factors related to reduced progression-free survival.

RESULTS

In all, 686 patients met the inclusion criteria, with PCA disease identified in 282 (41.1%) patients. Of those 282 patients with PCMMD, disease severity ranged from 99 (35.1%) with mild, 72 (25.5%) with moderate, and 111 (39.4%) with severe. The total number of postoperative complications was significantly associated with PCMMD severity (P=0.0067). Additionally, PCMMD severity correlated with worse postoperative modified Rankin Scale scores (P<0.0001). At a mean follow-up of 6.0±3.9 (range, 0.1-25.0) years, a total of 60 (12.6%) patients showed new/worsening PCMMD. The overall postoperative, progression-free survival in patients with PCMMD was 95.4% at 1 year, 82.4% at 3 years, 68.8% at 5 years, and 28.3% at 10 years, with prognostic factors for progression including preoperative PCMMD status, history of tobacco use, and hypertension (P<0.0001, P<0.001, and P<0.0001, respectively).

CONCLUSIONS

PCA disease involvement in MMD is associated with higher rates of ischemic perioperative complications and worsened functional outcomes, likely due to reduced collateral flow. Ten-year progression of PCA disease is highly likely and should be monitored throughout follow-up; future studies will assess the impact of PCA disease progression on long-term outcomes.

Effects of superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis on the cerebrospinal fluid gas tensions and pH in hemodynamically compromised patients

PURPOSE

This study was aimed to directly measure cerebrospinal fluid (CSF) gas tensions and pH before and after STA-MCA anastomosis for occlusive carotid artery diseases to investigate its direct effects on the ischemic brain.

METHODS

This study included 9 patients who underwent STA-MCA anastomosis on the basis of CBF studies. About 1 mL of CSF was collected before and after bypass procedures, and CSF pH, CSF PO2, and CSF PCO2 were measured with a blood gas analyzer. As the controls, the CSF was collected from 6 patients during surgery for unruptured cerebral aneurysm. CSF PO2 and CSF PCO2 were expressed as the ratio to PaO2 and PaCO2, respectively.

RESULTS

Before bypass procedure, CSF PO2/PaO2 was 0.88 ± 0.16, being lower than the controls (1.10 ± 0.09; P = 0.005). CSF PCO2/PaCO2 was 0.93 ± 0.13, being higher than the controls (0.84 ± 0.06; P = 0.039). Ipsilateral-to-contralateral CBF ratio had a positive correlation with CSF PO2/PaO2 (P = 0.0028) but a negative correlation with the CSF PCO2/PaCO2 (P = 0.0045). STA-MCA anastomosis increased CSF pH from 7.402 ± 0.133 to 7.504 ± 0.126 (P = 0.0011) and CSF PO2/PaO2 from 0.88 ± 0.16 to 1.05 ± 0.26 (P = 0.018) but decreased CSF PCO2/PaCO2 from 0.93 ± 0.13 to 0.70 ± 0.17 (P = 0.0006).

CONCLUSION

The severity of cerebral ischemia before surgery is intensely reflected in the gas tensions and pH of the CSF. STA-MCA anastomosis carries dramatic effects on CSF gas tensions and pH in hemodynamically compromised patients. CSF would be a valuable surrogate biomarker to monitor the severity of cerebral ischemia.

Risk Factors for Ischemic Stroke After Revascularization Surgery in Patients with Moyamoya Disease: An Age-Stratified Comparative Meta-Analysis

BACKGROUND

Patients who undergo revascularization surgery for moyamoya disease may develop postoperative ischemic stroke (pIS). Several studies have sought to identify risk factors; however, the findings remain highly inconsistent.

METHODS

PubMed, Scopus, and Web of Science were used to extract references. The first phase of screening required the studies to be in English, involve patients surgically treated for moyamoya disease, and report pIS. The second phase required the studies to provide ≥10 patients and include a control group.

RESULTS

All 22 studies were rated as high quality. Univariate analysis identified pediatrics <3 years of age as a risk factor for pIS (odds ratio [OR], 7.60; P < 0.0001). Among adult patients only, diabetes (OR, 2.10; P = 0.005), a Suzuki grade greater than 3 (OR, 1.74; P = 0.005), mean intraoperative systolic blood pressure (OR, 1.04; P < 0.0001), mean intraoperative diastolic blood pressure (OR, 1.04; P = 0.002), and revascularization in the left hemisphere (OR, 2.09; P = 0.001) were risk factors. Among both age groups, preoperative ischemic stroke (OR, 2.59; P < 0.00001) was a risk factor for pIS. Additionally, perioperative antiplatelet drug administration was a protective factor for specifically acute postoperative white thrombus among adult patients (OR, 0.35; P = 0.002).

CONCLUSIONS

In addition to the methods discussed that can mitigate the risk of pIS, the risk factors identified in our analysis may be of great value among surgeons for identifying high-risk patients in order to apply prophylactic measures, as well as scheduling longer and more frequent follow-up visits.

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.

European Stroke Organisation (ESO) Guidelines on Moyamoya angiopathy: Endorsed by Vascular European Reference Network (VASCERN)

The European Stroke Organisation (ESO) guidelines on Moyamoya Angiopathy (MMA), developed according to ESO standard operating procedure and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, were compiled to assist clinicians in managing patients with MMA in their decision making. A working group involving neurologists, neurosurgeons, a geneticist and methodologists identified nine relevant clinical questions, performed systematic literature reviews and, whenever possible, meta-analyses. Quality assessment of the available evidence was made with specific recommendations. In the absence of sufficient evidence to provide recommendations, Expert Consensus Statements were formulated. Based on low quality evidence from one RCT, we recommend direct bypass surgery in adult patients with haemorrhagic presentation. For ischaemic adult patients and children, we suggest revascularization surgery using direct or combined technique rather than indirect, in the presence of haemodynamic impairment and with an interval of 6–12 weeks between the last cerebrovascular event and surgery. In the absence of robust trial, an Expert Consensus was reached recommending long-term antiplatelet therapy in non-haemorrhagic MMA, as it may reduce risk of embolic stroke. We also agreed on the utility of performing pre- and post- operative haemodynamic and posterior cerebral artery assessment. There were insufficient data to recommend systematic variant screening of RNF213 p.R4810K. Additionally, we suggest that long-term MMA neuroimaging follow up may guide therapeutic decision making by assessing the disease progression. We believe that this guideline, which is the first comprehensive European guideline on MMA management using GRADE methods will assist clinicians to choose the most effective management strategy for MMA.

Validation of the Berlin Grading System for moyamoya angiopathy with the use of [15O]H2O PET

The Berlin Grading System assesses clinical severity of moyamoya angiopathy (MMA) by combining MRI, DSA, and cerebrovascular reserve capacity (CVRC). Our aim was to validate this grading system using [15O]H2O PET for CVRC. We retrospectively identified bilateral MMA patients who underwent [15O]H2O PET examination and were treated surgically at our department. Each hemisphere was classified using the Suzuki and Berlin Grading System. Preoperative symptoms and perioperative ischemias were collected, and a logistic regression analysis was performed. A total of 100 hemispheres in 50 MMA patients (36 women, 14 men) were included. Using the Berlin Grading System, 2 (2.8%) of 71 symptomatic hemispheres were categorized as grade I, 14 (19.7%) as grade II, and 55 (77.5%) as grade III. The 29 asymptomatic hemispheres were characterized as grade I in 7 (24.1%) hemispheres, grade II in 12 (41.4%), and grade III in 10 (34.5%) hemispheres. Berlin grades were independent factors for identifying hemispheres as symptomatic and higher grades correlated with increasing proportion of symptomatic hemispheres (p < 0.01). The Suzuki grading did not correlate with preoperative symptoms (p = 0.26). Perioperative ischemic complications occurred in 8 of 88 operated hemispheres. Overall, complications did not occur in any of the grade I hemispheres, but in 9.1% (n = 2 of 22) and 9.8% (n = 6 of 61) of grade II and III hemispheres, respectively. In this study, we validated the Berlin Grading System with the use of [15O]H2O PET for CVRC as it could stratify preoperative symptomatology. Furthermore, we highlighted its relevance for predicting perioperative ischemic complications.

Use of Intraoperative Neuronavigation to Identify Transdural Collaterals in Moyamoya Vasculopathy: A Simple Way to Make It Safer

INTRODUCTION

Transdural collaterals (TC) from the external carotid artery must be preserved when operating on patients with moyamoya vasculopathy. Several techniques have been used to identify the superficial temporal artery (STA) and middle meningeal artery (MMA) during surgery and prevent their damage. However, the use of neuronavigation for this specific purpose has never been described in the literature. We describe an operative case in which neuronavigation was used to preserve the TC (originating from the MMA), detailing our technique step by step and reviewing alternative methods previously reported.

CASE PRESENTATION

A 6-year-old girl with moyamoya disease, who had developed marked bilateral TC from the MMA sparing the middle cerebral artery territory, underwent staged bilateral indirect revascularization surgery. Intraoperative neuronavigation was used to identify the STA and MMA with their main branches during skin incision, craniotomy, and dural opening. The neuronavigation matched the intraoperative findings exactly, and the target structures remained undamaged. The patient was discharged home after both surgeries with no neurological deficits. One year following surgery, the patient has excellent collateralization from both STAs and is asymptomatic and neurologically intact.

CONCLUSION

With the use of intraoperative neuronavigation, the STA, MMA, and their main branches, as well as their relationship to the bone, can be identified and preserved. This approach can help in preventing undesirable injury to TC during surgery and may potentially prevent perioperative stroke in patients with moyamoya vasculopathy undergoing revascularization surgery.

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.

Clinical Management of Moyamoya Patients

Moyamoya angiopathy (MMA) is a peculiar cerebrovascular condition characterized by progressive steno-occlusion of the terminal part of the internal carotid arteries (ICAs) and their proximal branches, associated with the development of a network of fragile collateral vessels at the base of the brain. The diagnosis is essentially made by radiological angiographic techniques. MMA is often idiopathic (moyamoya disease-MMD); conversely, it can be associated with acquired or hereditary conditions (moyamoya Syndrome-MMS); however, the pathophysiology underlying either MMD or MMS has not been fully elucidated to date, and this poor knowledge reflects uncertainties and heterogeneity in patient management. MMD and MMS also have similar clinical expressions, including, above all, ischemic and hemorrhagic strokes, then headaches, seizures, cognitive impairment, and movement disorders. The available treatment strategies are currently shared between idiopathic MMD and MMS, including pharmacological and surgical stroke prevention treatments and symptomatic drugs. No pharmacological treatment able to reverse the progressive disappearance of the ICAs has been found to date in both idiopathic and syndromic cases. Antithrombotic agents are usually prescribed in ischemic MMA, although the coexisting hemorrhagic risk should be considered. Surgical revascularization techniques, which are currently the best available treatment in symptomatic MMA, are associated with good long-term outcomes and reduced ischemic and hemorrhagic risks. Given the lack of dedicated randomized clinical trials, current treatment is mainly based on observational studies and physicians’ and surgeons’ expertise.

Contralateral improvement of cerebrovascular reactivity and TIA frequency after unilateral revascularization surgery in moyamoya vasculopathy

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Contralateral cerebrovascular reactivity may improve after unilateral surgery in moyamoya.

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TIA frequency from the contralateral hemisphere can decrease after unilateral moyamoya surgery.

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These findings support staged rather than direct bilateral surgery in moyamoya.

Objective

Moyamoya vasculopathy is a rare, often bilateral disease characterized by progressive stenosis and occlusion of the distal internal carotid artery, leading to a progressive deterioration of cerebrovascular reactivity (CVR) and increased risk of transient ischemic attacks (TIAs), infarction and hemorrhage. Surgical revascularization is a widely accepted symptomatic treatment, often performed bilaterally in one or two stages. To possibly further optimize treatment strategy, we investigated the effect of unilateral revascularization surgery on the CVR of, and TIA frequency originating from, the contralateral hemisphere.

Methods

From our database of 143 moyamoya vasculopathy patients we selected those with bilateral disease, who underwent hemodynamic imaging ([15O]H2O positron emission tomography (PET)-CT with acetazolamide challenge) before and 14 months (median) after unilateral revascularization. We evaluated CVR in three regions per hemisphere, and averaged these per hemisphere for statistical comparison. Conservatively treated patients were showed as a comparison group. To examine TIA frequency, we selected patients who presented with TIAs that (also) originated from the contralateral – not to be operated – hemisphere. We scored changes in CVR and TIA frequency of the ipsilateral and contralateral hemisphere over time.

Results

Seven surgical and seven conservative patients were included for CVR comparison. Of the 20 scored contralateral regions in the surgical group, 15 showed improved CVR after unilateral revascularization, while 5 remained stable. The averaged scores improved significantly for both hemispheres. In conservatively treated patients, however, only 3 of the 20 scored regions improved in the least-affected (contralateral) hemispheres, and 9 deteriorated. From the 6 patients with contralateral TIAs at presentation, 4 had a decreased TIA frequency originating from the contralateral hemisphere after unilateral surgery, while 2 patients remained stable.

Conclusion

Both CVR and TIA frequency in the contralateral hemisphere can improve after unilateral revascularization surgery in bilateral MMV.

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

BACKGROUND

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

OBJECTIVE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Validation and Application for the Berlin Grading System of Moyamoya Disease in Adult Patients

BACKGROUND

Traditional moyamoya disease (MMD) classification relies on morphological digital subtraction angiography (DSA) assessment, which do not reflect hemodynamic status, clinical symptoms, or surgical treatment outcome.

OBJECTIVE

To (1) validate the new Berlin MMD preoperative symptomatology grading system and (2) determine the clinical application of the grading system in predicting radiological and clinical outcomes after surgical revascularization.

METHODS

Ninety-six MMD patients (192 hemispheres) with all 3 investigations (DSA, magnetic resonance imaging [MRI], Xenon-CT) performed preoperatively at our institution (2007-2013) were included. Two clinicians independently graded the imaging findings according to the proposed criteria. Patients' modified Rankin Score (mRS) scores (preoperative, postoperative, last follow-up), postoperative infarct (radiological, clinical) were collected and statistical correlations performed.

RESULTS

One hundred fifty-seven direct superficial temporal artery-middle cerebral artery bypasses were performed on 96 patients (66 female, mean age 41 yr, mean follow-up 4.3 yr). DSA, MRI, and cerebrovascular reserve capacity were independent factors associated hemispheric symptomatology (when analyzed individually or in the combined grading system). Mild (grade I), moderate (grade II), severe (grade III) were graded in 45, 71, and 76 hemispheres respectively; of which, clinical symptoms were found in 33% of grade I, 92% of grade II, 100% of grade III hemispheres (P < .0001). Two percent of grade I, 11% of grade II, 20% of grade III hemispheres showed postoperative radiological diffusion weighted image-positive ischemic changes or hemorrhage on MRI (P = .018). Clinical postoperative stroke was observed in 1.4% of grade II, 6.6% of grade III hemispheres (P = .077). The grading system also correlated well to dichotomized mRS postoperative outcome.

CONCLUSION

The Berlin MMD grading system is able to stratify preoperative hemispheric symptomatology. Furthermore, it correlated with postoperative new ischemic changes on MRI, and showed a strong trend in predicting clinical postoperative stroke.

Direct versus indirect bypass procedure for the treatment of ischemic moyamoya disease: results of an individualized selection strategy

OBJECTIVE

The only effective treatment for ischemic moyamoya disease (iMMD) is cerebral revascularization by an extracranial to intracranial bypass. The preferred revascularization method remains controversial: direct versus indirect bypass. The purpose of this study was to test the hypothesis that method choice should be personalized based on angiographic, hemodynamic, and clinical characteristics to balance the risk of perioperative major stroke against treatment efficacy.

METHODS

Patients with iMMD were identified retrospectively from a prospectively maintained database. Those with mild to moderate internal carotid artery or M1 segment stenosis, preserved cerebrovascular reserve, intraoperative M4 segment anterograde flow ≥ 8 ml/min, or the absence of frequent and severe transient ischemic attacks (TIAs) or stroke had been assigned to indirect bypass. The criteria for direct bypass were severe ICA or M1 segment stenosis or occlusion, impaired cerebrovascular reserve or steal phenomenon, intraoperative M4 segment retrograde flow or anterograde flow < 8 ml/min, and the presence of frequent and severe TIAs or clinical strokes. The primary study endpoint was MRI-confirmed symptomatic stroke ≤ 7 days postoperatively resulting in a decline in the modified Rankin Scale (mRS) score from preoperatively to 6 months postoperatively. As a secondary endpoint, the authors assessed 6-month postoperative DSA-demonstrated revascularization, which was classified as < 1/3, 1/3-2/3, or > 2/3 of the middle cerebral artery territory.

RESULTS

One hundred thirty-eight patients with iMMD affecting 195 hemispheres revascularized in the period from March 2016 to June 2018 were included in this analysis. One hundred thirty-three hemispheres were revascularized with direct bypass and 62 with indirect bypass. The perioperative stroke rate was 4.7% and 6.8% in the direct and indirect groups, respectively (p = 0.36). Degree of revascularization was higher in the direct bypass group (p = 0.03). The proportion of patients improving to an mRS score 0-1 (from preoperatively to 6 months postoperatively) tended to be higher in the direct bypass group, although the difference between the two bypass groups was not statistically significant (p = 0.27).

CONCLUSIONS

The selective use of an indirect bypass procedure for iMMD did not decrease the perioperative stroke rate. Direct bypass provided a significantly higher degree of revascularization. The authors conclude that direct bypass is the treatment of choice for iMMD.

Cerebral Revascularization Accelerates the Angiographic Staging Progression of the Operated Hemisphere in a Pediatric Patient With Moyamoya Disease

BACKGROUND AND OBJECTIVE

Angiographic staging progression in the operated hemisphere of patient with moyamoya disease (MMD) is a common phenomenon that neurosurgeons may encounter. However, few studies have been carried out to demonstrate the correlation between the operation and angiographic staging progression. This study aimed to reveal whether cerebral revascularization would affect the stage progression in patient with MMD.

METHODS

A total of 20 pediatric patients with bilateral MMD were included in this study. All enrolled patients were at the similar Suzuki angiographic staging on bilateral hemispheres and cerebral revascularization was performed in unilateral hemisphere. Angiographic examination was performed in the first year after the operation to evaluate the progression of the lesions.

RESULTS

Cerebral revascularizations including direct bypass or encephaloduroarteriosynangiosis were performed in 20 hemispheres. During the follow-up, the incidence of stage progression in the operated hemisphere was significantly higher than in the contralateral side (80.0% versus 20.0%, respectively; P = 0.036) and the interval of disease progression was significantly shorter in the operated side than in the contralateral side (mean interval time, 7.3 versus 10 months). Earlier Suzuki stage on hemisphere represented faster pace of stage progression compared with server Suzuki stage (OR = -0.612, P = 0.004), while neoformative collaterals had not significant correlation with the progression pace. The leptomeningeal collaterals from the posterior circulation decreased in almost all operated hemisphere, while gradually increasing in the contralateral hemisphere. Symptoms were improved in all patients after operation.

CONCLUSION

Cerebral revascularization would significantly accelerate the angiographic staging progression on the treated hemisphere, while it would not cause the deterioration of the patient's condition. The progression pace was associated with Suzuki stage.

Combined (direct and indirect) revascularization in adult patients with moyamoya disease

The study objective is to analyze the results of combined (direct and indirect) brain revascularization in adult patients with moyamoya disease. 

Materials and methods. From February 2015 to August 2016, 12 operations were performed on 12 hemispheres in 7 patients (2 men, 5 women) with moyamoya disease. Six patients had bilateral disease, 1 – unilateral. The age of patients ranged from 25 to 60 year old, the average – 41 year old. Multislice computed tomography (MSCT) perfusion imaging of the brain with a stress test was made in every patient, MSCT angiography of the extraand intracranial arteries was perfomed. Stages of the disease were determined according to the Suzuki–Takaku classification: stage III was revealed in 5 patients, stage IV – in 2. To evaluate the clinical course of the disease the Matsushima classification was used: type VI – in 2 cases, type III – in 2, type IV – in 1, type V – in 1. In 1 case, the pathological vascular network of 1 hemisphere was detected by accident. Extracranial-intracranial (EC–IC) bypass and encephaloduromyosynangiosis (EDMS) was used in 3 cases; a double-barreled EC–IC bypass and EDMS – in 3; a double-barreled EC–IC bypass and encephaloduroperiosteomyosynangiosis – in 1; EC–IC bypass and encephaloduroarteriomyosynangiosis (EDAMS) – in 3. In 1 case was perfomed EC–IC bypass and encephaloduroperiosteosynangiosis. Only indirect revascularization was performed in 1 case – EDAMS. We assessed the neurological status in the follow-up period (5–11 months); MSCT angiography and MSCT perfusion imaging of the brain were performed. 

Results. All patients in follow-up period demonstrated the increase of cerebrovascular reserve according to MSCT perfusion imaging of the brain with stress tests. Stroke, epilepsy, surgical complications were not detected in the postoperative period. In 1 case, the left-hand monoparesis regressed.

Conclusion. The combined (direct and indirect) revascularization may be effective in adult patients with moyamoya disease. To obtain more objective conclusions it is necessary to analyze the long-term results of interventions.