Surgical outcomes and predictors of stroke in a North American white and African American moyamoya population

Moyamoya Disease Causing Stroke in the Setting of Cocaine Use and Uncontrolled Hypertension Due to Primary Hyperaldosteronism

Moyamoya disease is a cerebrovascular disease characterized by stenosis of large intracranial arteries and the development of smaller collateral vessels. Moyamoya may cause strokes and stroke-like symptoms in young patients. It has also been linked to autoimmune diseases and neuropsychiatric conditions. We present a case of moyamoya disease in a young patient with concomitant hyperaldosteronism, uncontrolled hypertension, and cocaine use disorder, along with features of antisocial personality disorder. This is a unique presentation of an underlying neurological disease causing psychiatric features exacerbated by cocaine use, and it describes a rare clinical presentation that physicians should consider in patients with moyamoya disease.

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.

Characteristics of Moyamoya Disease in the Older Population: Is It Possible to Define a Typical Presentation and Optimal Therapeutical Management?

Whereas several studies have been so far presented about the surgical outcomes in terms of mortality and perioperative complications for elderly patients submitted to neurosurgical treatments, the management of elderly moyamoya patients is unclear. This review aims to explore the available data about the clinical manifestation, characteristics, and outcome after surgery of older patients with moyamoya arteriopathy (MA). We found only two articles strictly concerning elderly patients with MA. We have also evaluated other reported adult series of moyamoya patients, including elderly cases in their analysis. Patients with MA above 50 years old may be considered a peculiar subset in which patients are often presenting with ischemic symptoms and a higher Suzuki grade. Conservative treatment may be proposed in asymptomatic or stable cases due to their fragility and possible increase of post-operative complications, while the best surgical options in symptomatic cases are still under investigation, although we believe that a minimal invasive superficial temporal artery—middle cerebral artery bypass could be considered the treatment of choice for the immediate effect on brain perfusion with a limited rate of post-operative complications.

Patients with Moyamoya Vasculopathy Evaluated at a Single-Center in The Netherlands; Clinical Presentation and Outcome

Information on presentation and outcome of moyamoya vasculopathy (MMV) in European countries is limited. We investigated patient characteristics, treatment and outcome of patients with MMV. We retrieved patient characteristics and treatment information and determined functional outcome (modified Rankin Score (mRS); type of school/work) by structured telephone interviews. We performed uni- and multivariable logistic regression analysis to determine predictors of poor outcome. We included 64 patients with bilateral MMV. In children (31 patients), median age was 5 years (interquartile range (IQR) 2-11) and in adults (33 patients), it was 33 years (IQR 28-41). Predominant mode of presentation was ischemia (children 84%; adults 88%). Modified Rankin Scale (mRS) at presentation was ≤2 in 74%. Revascularization was performed in 42 patients (23 children). Median follow-up time was 46 months (IQR 26-90). During this period, 16 patients had recurrent stroke(s) and four patients died. In 73% of the patients (83% surgical group; 55% medically treated group), mRS was ≤2; 46% were able to return to regular school or work, of whom only 41% were on the same level. Univariable analysis revealed that surgical treatment was associated with lower odds of poor outcome ((mRS ≥ 3), OR 0.24; p = 0.017). This association was no longer statistically significant (OR 3.47; p = 0.067) in the multivariable model, including age and diagnosis (moyamoya disease or moyamoya syndrome). In this cohort of patients with MMV who presented in a single European center, a large proportion had good functional outcome. Nevertheless, less than half were able to attend regular school or were able to work at their previous level, indicating a large impact of the disease on their life.

Racial phenotypes in moyamoya disease: a comparative analysis of clinical presentation and natural history in a single multiethnic cohort of 250 hemispheres

OBJECTIVE

The authors aimed to determine whether differences exist in presentation and natural history when comparing Asian patients with moyamoya disease (MMD) to those of other ethnicities in North America.

METHODS

A database of 137 patients with MMD presenting to their institution between 1994 and 2015 was reviewed. Baseline characteristics and outcome variables, including stroke and functional outcome, were compared between Asian and non-Asian patients. Unadjusted Kaplan-Meier survival analysis and adjusted Cox regression models were used to compare stroke-free survival and stroke hazard after diagnosis among hemispheres of both racial groups. The analysis was stratified by age group, and censoring was performed until last follow-up or at the time of surgery. Because the relative rate of stroke changed between Asian and non-Asian adults after 1.5 years of follow-up, a time-segmented analysis focusing on the period 1.5 years after diagnosis was performed.

RESULTS

The cohort comprised 23% (31/137) Asian and 77% (106/137) non-Asian patients with MMD with a bimodal age distribution. Non-Asian patients had a higher prevalence of increased BMI (p = 0.02) and smoking (p = 0.04). Among patients who presented with stroke (n = 90), hemorrhage was significantly more common among Asians (p = 0.02). The natural history analysis included 250 hemispheres: 67 pediatric and 183 adult hemispheres. The overall mean follow-up duration since diagnosis was 3.3 years. Among adults, Asian patients had a higher incidence of stroke (8.0 per 100 person-years vs 3.0 per 100 person-years) over a mean follow-up of 3.3 years, but results were not statistically significant (p = 0.45). In the period beginning 1.5 years after diagnosis, Asian adults had a significantly higher hazard of stroke over a mean follow-up of 7.7 years, while controlling for sex, hypertension, and stroke before diagnosis (hazard ratio 8.8, p = 0.02). Among pediatric patients, Asians also had a higher stroke incidence (10.0 per 100 person-years vs 3.5 per 100 person-years) over a mean follow-up of 3.2 years; however, results did not reach statistical significance (p = 0.40). Functional outcome was similar between both ethnic groups at last follow-up (p = 0.57).

CONCLUSIONS

This study suggests a comparatively more progressive course of MMD in Asians. Further studies are required to fully characterize the phenotypic distinctions between different races and underlying pathophysiological mechanisms.

Moyamoya disease versus moyamoya syndrome: comparison of presentation and outcome in 338 hemispheres

OBJECTIVE

Phenotypic differences between moyamoya disease (MMD) and moyamoya syndrome (MMS) remain unclear. The purpose of this study was to evaluate whether such differences exist when presentation, procedure-related, and outcome variables are compared quantitatively.

METHODS

The study cohort included 185 patients with moyamoya presenting to the Johns Hopkins Medical Institutions between 1994 and 2015. Baseline demographic, angiographic, and clinical characteristics were compared between patients with MMS and MMD, in addition to procedure-related complications and length of stay (LOS) after surgery. Stroke-free survival was compared between both disease variants after diagnosis. Kaplan-Meier analysis and Cox proportional hazards regression were used to compare stroke-free survival between surgically treated and conservatively managed hemispheres in both types of disease, while evaluating interaction between disease variant and management.

RESULTS

The cohort consisted of 137 patients with MMD (74%) with a bimodal age distribution and 48 patients with MMS (26%) who were mostly under 18 years of age (75%). Underlying diseases included sickle cell disease (48%), trisomy 21 (12%), neurofibromatosis (23%), and other disorders (17%). Patients with MMS were younger (p < 0.001) and less likely to be female (p = 0.034). Otherwise, baseline characteristics were statistically comparable. The rate of surgical complications was 33% in patients with MMD and 16% in patients with MMS (p = 0.097). Both groups of patients had a similar LOS after surgery (p = 0.823). Survival analysis (n = 330 hemispheres) showed similar stroke-free survival after diagnosis (p = 0.856) and lower stroke hazard in surgically managed patients in both MMD (hazard ratio [HR] 0.29, p = 0.028) and MMS (HR 0.62, p = 0.586). The disease variant (MMD vs MMS) did not affect the relationship between management approach (surgery vs conservative) and stroke hazard (p = 0.787).

CONCLUSIONS

MMD and MMS have largely comparable clinical and angiographic phenotypes with analogously favorable responses to surgical revascularization.

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.

Clinical Use of Cerebrovascular Compliance Imaging to Evaluate Revascularization in Patients With Moyamoya

BACKGROUND

Surgical revascularization is often performed in patients with moyamoya, however routine tools for efficacy evaluation are underdeveloped. The gold standard is digital subtraction angiography (DSA); however, DSA requires ionizing radiation and procedural risk, and therefore is suboptimal for routine surveillance of parenchymal health.

OBJECTIVE

To determine whether parenchymal vascular compliance measures, obtained noninvasively using magnetic resonance imaging (MRI), provide surrogates to revascularization success by comparing measures with DSA before and after surgical revascularization.

METHODS

Twenty surgical hemispheres with DSA and MRI performed before and after revascularization were evaluated. Cerebrovascular reactivity (CVR)-weighted images were acquired using hypercapnic 3-Tesla gradient echo blood oxygenation level-dependent MRI. Standard and novel analysis algorithms were applied (i) to quantify relative CVR (rCVRRAW), and decompose this response into (ii) relative maximum CVR (rCVRMAX) and (iii) a surrogate measure of the time for parenchyma to respond maximally to the stimulus, CVRDELAY. Measures between time points in patients with good and poor surgical outcomes based on DSA-visualized neoangiogenesis were contrasted (signed-rank test; significance: 2-sided P < .050).

RESULTS

rCVRRAW increases (P = .010) and CVRDELAY decreases (P = .001) were observed pre- vs post-revascularization in hemispheres with DSA-confirmed collateral formation; no difference was found pre- vs post-revascularization in hemispheres with poor revascularization. No significant change in rCVRMAX post-revascularization was observed in either group, or between any of the MRI measures, in the nonsurgical hemisphere.

CONCLUSION

Improvement in parenchymal compliance measures post-revascularization, primarily attributed to reductions in microvascular response time, is concurrent with collateral formation visualized on DSA, and may be useful for longitudinal monitoring of surgical outcomes.

Identification of HLA-DRB1*04:10 allele as risk allele for Japanese moyamoya disease and its association with autoimmune thyroid disease: A case-control study

Background and purpose

Moyamoya disease (MMD) is a progressive cerebrovascular disease with unknown etiology. Growing evidence suggest its involvement of autoimmune and genetic mechanisms in the pathogenesis of MMD. This study aims to clarify the association between HLA allele and MMD.

Methods

Case-control study: the DNA of 136 MMD patients in Japan was extracted and the genotype of human leukocyte antigen (HLA) from this DNA was determined by super-high-resolution single-molecule sequence-based typing using next-generation sequencing. Next, the frequency of each HLA allele (HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DQB1, and HLA-DPB1) was compared with those in the Japanese control database. In addition, haplotype estimation was performed using the expectation maximization algorithm.

Results

The frequencies of the HLA-DRB1*04:10 allele (4.77% vs. 1.47% in the control group; P = 1.7 × 10⁻³; odds ratio [OR] = 3.35) and of the HLA-DRB1*04:10–HLA-DQB1*04:02 haplotype (haplotype frequency 4.41% vs. 1.35% in the control group; P = 2.0 × 10⁻³; OR = 3.37) significantly increased. The frequency of thyroid diseases, such as Graves’ disease and Hashimoto thyroiditis, increased in HLA-DRB1*04:10-positive MMD patients compared with that in HLA-DRB1*04:10-negative MMD patients.

Conclusions

HLA-DRB1*04:10 is a risk allele and HLA-DRB1*04:10–HLA-DQB1*04:02 a risk haplotype for MMD. In addition, HLA-DRB1*04:10 is associated with thyroid disease in MMD patients.

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.

Risk factors for and outcomes of postoperative complications in adult patients with moyamoya disease

OBJECTIVE

The risk factors and clinical significance of postoperative complications in moyamoya disease are still unclear. The aim of this study was to investigate the predictors of postoperative complications in moyamoya disease and examine the impact of complications on outcomes.

METHODS

The authors reviewed consecutive cases involving adult moyamoya disease patients who underwent indirect, direct, or combined bypass surgery in their hospital between 2009 and 2015. Preoperative clinical characteristics and radiographic features were recorded. Postoperative complications within 14 days after surgery were examined. Multivariate logistic regression analyses were performed to identify the risk factors for either postoperative ischemia or postoperative cerebral hyperperfusion. Outcome data, including recurrent strokes and neurological status (modified Rankin Scale [mRS]) during follow-up, were collected. Outcomes were compared between patients who had complications with those without complications, using propensity-score analysis to account for between-group differences in baseline characteristics.

RESULTS

A total of 500 patients (610 hemispheres) were included in this study. Postoperative complications were observed in 74 operations (12.1%), including new postoperative ischemia in 30 cases (4.9%), hyperperfusion in 27 (4.4%), impaired wound healing in 12 (2.0%), and subdural effusion in 6 (1.0%). The complication rates for different surgery types were as follows: 12.6% (n = 25) for indirect bypass, 12.7% (n = 37) for direct bypass, and 10.0% (n = 12) for combined bypass (p = 0.726). Postoperative ischemic complications occurred in 30 hemispheres (4.9%) in 30 different patients, and postoperative symptomatic hyperperfusion occurred after 27 procedures (4.4%). Advanced Suzuki stage (OR 1.669, 95% CI 1.059-2.632, p = 0.027) and preoperative ischemic presentation (OR 5.845, 95% CI 1.654-20.653, p = 0.006) were significantly associated with postoperative ischemia. Preoperative ischemic presentation (OR 5.73, 95% CI 1.27-25.88, p = 0.023) and admission modified Rankin Scale (mRS) score (OR 1.81, 95% CI 1.06-3.10, p = 0.031) were significantly associated with symptomatic postoperative cerebral hyperperfusion syndrome (CHS). Compared with patients without postoperative complications, patients who experienced any postoperative complications had longer hospital stays and worse mRS scores at discharge (both p < 0.0001). At the final follow-up, no significant differences in functional disability (mRS score 3-6, 11.9% vs 4.5%, p = 0.116) and future stroke events (p = 0.513) between the 2 groups were detected.

CONCLUSIONS

Advanced Suzuki stage and preoperative ischemic presentation were independent risk factors for postoperative ischemia; the mRS score on admission and preoperative ischemic presentation were independently associated with postoperative CHS. Although patients with postoperative complications had worse neurological status at discharge, postoperative complications had no associations with future stroke events or functional disability during follow-up.

Encephaloduroarteriosynangiosis for pediatric moyamoya disease: long-term follow-up of 100 cases at a single center

OBJECTIVE The object of this study was to summarize the long-term effect of encephaloduroarteriosynangiosis (EDAS) for the treatment of pediatric moyamoya disease (MMD) and to investigate factors influencing the clinical outcomes of EDAS. METHODS Clinical features, angiographic findings, and clinical outcomes were analyzed among MMD patients younger than 18 years who had been treated with EDAS between 2002 and 2007 at the authors' institution. The Kaplan-Meier method was used to estimate stroke risk after EDAS. Predictors of neurological outcome were assessed. RESULTS One hundred fifteen patients were identified. The mean age at symptom onset was 7.3 ± 4.0 years. The incidence of familial MMD was 11.3%. The female/male ratio was 1:1.16. A total of 232 EDAS procedures were performed, and the incidence of postoperative complications was 3%. Postoperative digital subtraction angiography was performed in 54% of the patients, and about 80% of the hemispheres showed good or excellent results. Neovascularization showed significant correlations with delay time (from symptom onset to first operation), Suzuki stage, and preoperative stroke (all p < 0.05). Clinical follow-up was available in 100 patients with a mean follow-up of 124.4 ± 10.5 months. Ten-year cumulative survival was 96.5% after surgery, and the risk of stroke was 0.33%/person-year. An independent life with no significant disability was reported by 92% of the patients. A good outcome correlated with a low Suzuki stage (p = 0.001). Older children and those without preoperative stroke had better clinical outcomes (p < 0.05). CONCLUSIONS On the basis of long-term follow-up data, the authors concluded that EDAS is a safe and effective treatment for pediatric MMD, can reduce the risk of subsequent neurological events, and can improve quality of life. The risk of ischemia-related complications was higher in younger patients, and older children showed better outcomes. Compensation was greater with more prominent cerebral ischemia. The long-term clinical outcome largely depended on the presence and extent of preoperative stroke.

Risk Factors Associated with Neurologic Deterioration After Combined Direct and Indirect Revascularization in Patients with Moyamoya Disease on the East Coast of China

OBJECTIVE

Neurologic deterioration is the primary distinctive complication after revascularization surgery in patients with moyamoya disease (MMD). The present study investigated the risk factors for neurologic deterioration after combined direct and indirect revascularization in patients with MMD.

METHODS

A retrospective review of 123 patients with MMD undergoing 138 combined direct and indirect revascularization procedures was performed. Demographics, clinical manifestation, medical history, neurologic deterioration complications, and relevant information of the operation were recorded.

RESULTS

There were 25 (18.12%) postoperative neurologic deterioration complications (13 reversible neurologic deficits, 9 infarctions with neurologic sequelae, and 3 hemorrhages). Preoperative multiple symptom episodes and one-staged bilateral revascularization were significantly correlated with postoperative neurologic deterioration complications (P < 0.05 and P < 0.01, respectively). The incidence rate (26.39%) of postoperative neurologic deterioration in ischemic MMDs was significantly greater than hemorrhagic MMDs (7.69%; P < 0.01) In total, 34.78% of patients with transient ischemic attack onset and 22.45% of patients with infarction onset suffered from postoperative neurologic deterioration, and there was no significant difference between them (P > 0.05). Postoperative neurologic deterioration complications had no significant correlation with sex, age at the time of surgery, type of surgical procedure, unilateral MMD or not, interval between the last attack and operation, and history of thyroid disease, hypertension, and autoimmune disease.

CONCLUSIONS

Preoperative multiple symptom episodes and one-staged bilateral revascularization are risk factors associated with postoperative neurologic deterioration in patients with MMD. Therefore, 2 unilateral revascularization procedures performed successively rather than one-staged bilateral revascularization procedures should be performed in patients with bilateral MMD.

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.

Clinical Features, Surgical Treatment, and Long-Term Outcome in Elderly Patients with Moyamoya Disease

OBJECTIVE

To elucidate the clinical features, surgical treatment, and long-term outcome in elderly patients with moyamoya disease (MMD).

METHODS

We retrospectively reviewed 87 elderly patients with MMD at Beijing Tiantan Hospital. Clinical features, radiologic findings, and outcomes were analyzed.

RESULTS

The mean age at diagnosis was 54.0 ± 3.7 years. Familial occurrence was 2.3%. Underlying vascular risk factors was 74.7%. Infarction was the most common symptom in elderly MMD (40.2%). Most patients presented with Suzuki stage 4 or 5 MMD (51.2%). Posterior cerebral artery involvement was observed in 22 (25.3%) patients. The incidence of postoperative infarction or hemorrhages was 6.9%. Diabetes was identified as a predictor of adverse postoperative events. During the average follow-up of 35.5 ± 22.2 months, rebleeding in patients with hemorrhagic MMD was higher than in those with ischemic MMD (P < 0.05). What's more, the rate of perfusion improvement in surgically treated patients was higher than in conservatively treated patients 3 months after discharge (P < 0.05).

CONCLUSIONS

Infarction was the most common symptom in elderly MMD. More vascular risk factors, a higher grade of Suzuki stage, fewer familial cases, and posterior cerebral artery involvement were observed in elderly patients with MMD. Diabetes was a risk factor of postoperative events for elderly patients. Hemorrhagic MMD had a higher rate of rebleeding than the ischemic type. Although surgical revascularization procedures can improve cerebral perfusion, further study is needed to determine whether surgical revascularization is effective in elderly patients or with certain techniques.

Characteristics of infarction after encephaloduroarteriosynangiosis in young patients with moyamoya disease

OBJECTIVE Young patients with moyamoya disease can exhibit infarction after revascularization surgery. This analysis of the characteristics of infarction after encephaloduroarteriosynangiosis (EDAS) in young patients with moyamoya disease was undertaken in an effort to elucidate the infarction mechanism. METHODS The authors retrospectively collected clinical information and reviewed pre- and postoperative MRI studies from cases involving patients younger than 18 years who underwent EDAS for the treatment of moyamoya disease between January 2012 and February 2015. Infarction patterns were categorized into watershed, territorial, or mixed pattern. The Wilcoxon rank sum test, chi-square test, and Fisher exact test were used to compare the clinical and imaging variables between patient groups. The characteristics of patients with and without postoperative infarction were compared using univariate and multivariate analysis. The cumulative proportion of patients without postoperative infarction according to operation stage was calculated using the Kaplan-Meier method and the resulting curves were compared using the log-rank test. RESULTS In 100 patients, 171 EDAS procedures had been performed. There were 38 cases of preoperative infarction in 35 patients and 20 cases of postoperative infarction in 13 patients. Territorial infarction was more frequent in the postoperative infarction group than in the preoperative infarction group (55.0% vs 37.8%, p = 0.037). Infarction was more common on the bilateral or contralateral side of the operation after first-stage EDAS (9 [75.0%] of 12 infarctions) than in the second-stage operation (2 [25.0%] of 8 infarctions), but the difference was not statistically significant (p = 0.068). The frequency of postoperative infarction was not significantly different depending on the stage of the operation (p = 0.694). CONCLUSIONS An acute infarction pattern after EDAS was more frequently territorial, suggesting an underlying occlusive mechanism. Operation stage did not affect the rate of postoperative infarction occurrence.

Risk Factors for Newly Developed Cerebral Infarction After Surgical Revascularization for Adults with Moyamoya Disease

OBJECTIVE

It is important to recognize the incidence and risk factors for ischemic complications after surgical revascularization for moyamoya disease (MMD). However, most studies focus on pediatric MMD or pediatric and adult MMD. Our study identified the incidence and risk factors of newly developed cerebral infarction after surgical revascularization for adult MMD.

METHODS

Ischemic complications were defined as newly developed cerebral infarction within 15 days after surgery, as identified by imaging studies. To identify the incidence and these risk factors for adult patients ≥18 years, we retrospectively reviewed our experience with 194 adult MMD patients with 241 surgical revascularizations.

RESULTS

The incidence of symptomatic infarction after surgical revascularization was 5.8% (14 cases); 30 cases (12.4%) experienced a silent infarction. In univariate analysis, initial presentation as infarction, initial presentation as hemorrhage, transient ischemic attacks (TIAs) >3 times/month, involvement of the posterior cerebral artery (PCA), combined bypass, and using muscle for revascularization were variables related to the newly developed cerebral infarction. Multivariate analysis revealed that the following factors were independently associated with newly developed cerebral infarction after surgery: cerebral infarction as initial presentation (odds ratio [OR] 1.150; 95% confidence interval [CI] 1.038-1.273; P = 0.0073), TIAs >3times/month (OR 1.188; 95% CI 1.058-1.335; P = 0.0035), and PCA involvement (OR 1.095; 95% CI 1.005-1.194; P = 0.039).

CONCLUSIONS

Our findings demonstrate that newly developed, silent cerebral infarction developed more frequently than symptomatic cerebral infarction in adult patients. Cerebral infarction as initial presentation, frequent TIA before surgery, and PCA involvement were also independent risk factors for newly developed cerebral infarction after surgical revascularization for adult MMD.

Diagnosis of moyamoya disease: international standard and regional differences

Moyamoya disease is a chronic, occlusive cerebrovascular disease with unknown etiology characterized by bilateral steno-occlusive changes at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain. These diagnostic criteria of the moyamoya disease, stated by the Research Committee on Spontaneous Occlusion of the Circle of Willis (moyamoya disease) in Japan, are well established and generally accepted as the definition of this rare entity. On the contrary to the diagnosis of definitive moyamoya disease, there is some confusion in the terminology and understanding of quasi-moyamoya disease; moyamoya disease in association with various disease entities, such as atherosclerosis, autoimmune diseases, Down syndrome, etc. Although the clinical management is not affected by these semantic distinctions, terminological confusion may interfere with the international collaboration of the clinical investigation of these rare conditions. In this article, we sought to review the international standard and regional differences in the diagnosis of moyamoya disease and quasi-moyamoya disease.

Unstable moyamoya disease: clinical features and impact on perioperative ischemic complications

OBJECT

Unstable moyamoya disease, reasonably defined as cases exhibiting either rapid disease progression or repeated ischemic stroke, represents a challenge in the treatment of moyamoya disease. Despite its overall efficacy, direct bypass for such unstable disease remains controversial in terms of safety. This study aims to reveal factors associated with unstable disease and to assess its impact on postoperative silent or symptomatic ischemic lesions.

METHODS

This retrospective cohort study included both pediatric and adult patients with moyamoya disease who had undergone 140 consecutive direct bypass procedures at Kyoto University Hospital. “Unstable moyamoya disease” was defined as either the rapid progression of a steno-occlusive lesion or repeat ischemic stroke, either occurring within 6 months of surgery. The extent of progression was determined through a comparison of the findings between 2 different MR angiography sessions performed before surgery. The clinical variables of the stable and unstable disease groups were compared, and the association between unstable disease and postoperative diffusion-weighted imaging (DWI)–detected lesion was assessed through univariate and multivariate analyses with generalized estimating equations.

RESULTS

Of 134 direct bypass procedures performed after patients had undergone at least 2 sessions of MR angiography, 24 (17.9%) were classified as cases of unstable disease. Age younger than 3 years (p = 0.029), underlying disease causing moyamoya syndrome (p = 0.049), and radiographic evidence of infarction (p = 0.030) were identified as factors associated with unstable disease. Postoperative DWI-defined lesions were detected after 13 of 140 procedures (9.3%), although only 4 lesions (2.9%) could be classified as a permanent complication. The incidence of postoperative DWI-detected lesions in the unstable group was notable at 33.3% (8 of 24). Univariate analysis revealed that unstable disease (p < 0.001), underlying disease (p = 0.028), and recent stroke (p = 0.012) were factors associated with DWI-detected lesions. Unstable disease remained statistically significant after adjustment for covariates in both the primary and sensitivity analyses (primary analysis: OR 6.62 [95% CI 1.79–24.5]; sensitivity analysis: OR 5.36 [95% CI 1.47–19.6]).

CONCLUSIONS

Unstable moyamoya disease, more prevalent in younger patients and those with underlying disease, is a possible risk factor for perioperative ischemic complications. Recognition of unstable moyamoya disease may contribute to an improved surgical result through focused perioperative management based on appropriate surgical risk stratification.