Indirect Bypass Research Articles

Safety and Efficacy of Induced Hypertension and Hypervolemia in Preventing Neurologic Complications After Combined Direct and Indirect Bypass in Hemorrhagic-Onset Moyamoya Disease

Perioperative management of blood pressure in patients undergoing surgical revascularization for moyamoya disease (MMD) remains a controversial topic. We evaluated the safety and efficacy of induced hypertension and hypervolemia (IHH) in preventing neurologic complications during the perioperative period after direct surgical revascularization in a large hemorrhagic-onset moyamoya disease (HOMMD) cohort. We retrospectively reviewed a prospectively managed departmental database of all HOMMD patients treated between 1987 and 2019. The study included 122 direct surgical revascularization patients. Patients were separated into groups on the basis of the presence or absence of IHH therapy and evaluated for occurrence of 30-day risk of transient neurologic events (TNEs), ischemic, and hemorrhagic complications. Two-hundred and three revascularization procedures were performed on 122 patients for HOMMD treatment. Nineteen TNEs (9.4% of procedures) were observed in 18 (14.8%) patients. Two patients (1.6% and 1.0% of procedures) suffered from ischemic complications and 1 (0.8% and 0.5% of procedures) from hemorrhagic complications. No differences between groups in the severity, duration of TNEs, or length of hospital stay were noted. No patient in the IHH therapy group experienced a recurring TNE or readmission after discharge; however, this was not statistically significant owing to the small sample size. There were no differences in the rates of ischemic or hemorrhagic complications between groups with or without IHH therapy (P= 0.46 and 0.54, respectively). Induced hypertension and hypervolemia appear safe in HOMMD. There were no significant differences in complication or TNE rates between the groups with or without IHH therapy. While we believe it is important to employ IHH therapy in MMD patients who present with ischemic symptoms, these findings suggest that prophylactic IHH therapy may not be necessary in MMD patients presenting with hemorrhage.

Follow-up outcomes of different bypass surgical modalities for adults with ischaemic-type moyamoya disease

Purpose The preferred surgical method for treating adults with moyamoya disease (MMD) remains controversial. The purpose of this study was to compare the efficacy of different surgical methods in the treatment of adults with ischaemic-type MMD. Methods We retrospectively analyzed the data of patients with ischaemic-type MMD who underwent indirect bypass (IB), direct bypass (DB), or combined bypass (CB) at the First Affiliated Hospital of Zhengzhou University from January 2013 to December 2019. Postoperative complications, improvements in neurological function, haemodynamics, recurrent stroke and neovascularization were compared. Results A total of 310 adults (371 hemispheres) with ischaemic-type MMD were included in our study. Ninety, 127, and 154 hemispheres underwent IB, DB and CB, respectively. A total of 24 (6.5%) ischaemic events and 8 (2.8%) symptomatic hyperperfusion events occurred after the operations. There was no significant difference in postoperative complications among the three types of surgery (p = 0.300). During the follow-up period, there were 21 cases (5.7%) of recurrent ischaemia and 12 cases (3.2%) of recurrent haemorrhage. Kaplan-Meier survival analysis showed that the ischaemia-free survival of the CB group was significantly longer than that of the IB group (p = 0.047), but there was no significant difference in haemorrhage-free survival among the three groups (p = 0.660). Six months after the operation, DB and CB were superior to IB in improving cerebral blood flow and neovascularization (p = 0.002), but there was no significant difference in the improvement of neurological function among the three groups at the last follow-up (p = 0.784). Conclusion The three surgical methods achieved satisfactory results in the treatment of ischaemic-type MMD. DB and CB can significantly improve haemodynamics and reduce recurrent stroke. In terms of improving neurological function, the curative effect of the three surgical methods remains to be further explored.

A meta-analysis of comparisons of various surgical treatments for moyamoya diseases.

PurposeIschemia is one of the most familiar complications in the different procedures for moyamoya disease (MMD), but the optimal surgical approaches for MMD remain unknown. We aimed to evaluate the efficiency of various surgical treatments.MethodsA literature search word was performed through four databases such as Cochrane Library, Web of Science, PubMed, and EMBASE for the literature published until May 2021. The I 2 statistic was used to assess heterogeneity. A random/fixed‐effects model was used to pool.ResultsThere are a total of 18 studies including three surgical treatments such as including indirect, direct, and combined bypass in this study. The result revealed that indirect bypass was related to a higher incidence of recurrence stroke compared to the direct and combined bypass treatment (p = .001). Furthermore, the cases undergoing direct bypass were associated with a better angiographic change than the indirect bypass (OR = 3.254, p = .013).ConclusionThis meta‐analysis demonstrated a positive effect of using the direct and combined bypass to treat MMD compared to indirect bypass due to their lower rates of recurrence stroke.

Surgical Outcome of Encephaloduroarteriomyosynangiosis for Moyamoya Disease.

Indirect bypass surgeries for moyamoya disease have included modifications of procedures involving placement of the superficial temporal artery on the brain pial surface. We evaluate the functional and angiographic outcomes of patients treated with encephaloduroarteriomyosynangiosis (indirect) revascularization and examine the outcome in relation to demographic and radiological factors. Patients treated surgically for moyamoya disease over a 14-year period were identified. Demographics, clinical presentation, and radiology were analyzed to assign a stage for the disease (Suzuki staging) and the extent of revascularization (Matsushima grade) at the last follow-up. A modified Rankin score was used to assess the clinical status at presentation and the functional outcome at follow-up. There were 46 patients operated on by a single surgeon over a 14-year period. A higher incidence of motor deficits, seizures, and speech deficits was seen in the pediatric population. Age, sex, preoperative Suzuki disease stage, and hemispheric involvement had no bearing on angiographic outcome at last follow-up. Three of 46 patients (6.5%) developed immediate postoperative complications. Among 43 patients on follow-up, 39 had stable disease or showed improvement in clinical symptoms with 90% event-free status at last follow-up. Indirect revascularization procedures are an effective alternative to direct cerebral revascularizations in the early or advanced stages of moyamoya disease. This is effective in a predominant ischemic presentation as noted in our series.

Socioeconomic Inequities in the Surgical Management of Moyamoya Disease

Given the vasculopathic nature of moyamoya disease (MMD) and high susceptibility to ischemic events, patients with MMD often require surgical revascularization via an indirect or direct bypass, and analysis of disparities in receipt of appropriate management is critical. The 2012-2016 Nationwide Inpatient Sample was queried for patients admitted with a diagnosis of MMD using International Classification of Diseases codes. Patient baseline demographics, hospital characteristics, and associated symptoms were collected. Patients were grouped by receipt of bypass procedure, and propensity score matching was performed to identify socioeconomic disparities between operative and nonoperative groups. Inclusion criteria were met by 4474 patients (827 pediatric patients and 3647 adult patients). Mean (SD) age for pediatric patients was 10.4 (4.6) years and for adult patients was 40.5 (14.4) years. Among pediatric patients, Black and Hispanic/Latino patients were less likely to undergo revascularization surgery (odds ratio [OR] 0.49, 95% confidence interval [CI] 0.21-0.78, P ≤ 0.01; OR 0.47, 95% CI 0.26-0.84, P= < 0.01, respectively); among adult patients, Black and Hispanic/Latino patients were similarly less likely to undergo bypass procedures (OR 0.60, 95% CI 0.49-0.72, P ≤ 0.01; OR 0.73, 95% CI 0.55-0.96, P=0.01, respectively). Pediatric and adult patients in thelowest and next to lowest income quartiles were also less likely to receive operative treatment (pediatric patients: OR 0.61, 95% CI 0.40-0.94, P= 0.02; OR 0.64, 95% CI0.42-0.98, P=0.04, respectively; adult patients: OR 0.82, 95% CI 0.88-0.98, P= 0.03). Further investigation into socioeconomic disparities in adult and pediatric patients with MMD is warranted given the potential for inequities in access to appropriate intervention.

Postoperative neovascularization, cerebral hemodynamics, and clinical prognosis between combined and indirect bypass revascularization procedures in hemorrhagic moyamoya disease

ObjectiveWe evaluated what few studies emphasized the postoperative collateral formation and cerebral hemodynamics of hemorrhagic moyamoya disease (MMD). MethodsHemorrhagic MMD patients treated surgically were retrospectively collected and dichotomized into combined bypass (CB) and indirect bypass (IB) groups. CB used superficial temporal artery-to-middle cerebral artery anastomosis combined with encephaloduroarteriomyosynangiosis (STA-MCA+EDAMS), and IB used encephaloduroarteriomyosynangiosis (EDAMS) for revascularization. Postoperative complications and clinical prognosis, as well as pre- and post-operative Modified Rankin Scale (mRS), collateral circulation status, and cerebral hemodynamics were observed and compared between the CB and IB groups. ResultsA total of 37 patients with hemorrhagic MMD were identified. Of the 68 cerebral hemispheres, 47(69.1%) were combined revascularization, and the rest were indirect. During an average follow-up of 16.5 ± 8.7 months, the recurrent stroke events were significantly lower, as well as having a postoperative mRS scores≤ 2. A satisfactory postoperative collateral formation, and an improved dilation or extension of the anterior choroidal/posterior communication artery (AchA/PcoA) were significantly higher in the CB group than in the IB group (all P < .05). Compared with preoperative cerebral hemodynamics, relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), mean transit time (MTT), and relative time to peak (rTTP) in the CB group; rCBF, rCBV, and MTT in the IB group were significantly improved (all P < .001). The CB group’s postoperative rCBF was significantly improved compared with the IB group (P < .001). ConclusionsSTA-MCA bypass combined with EDAMS can obtain better postoperative collateral formation, cerebral hemodynamics, and clinical prognosis than EDAMS alone.

Direct vs Indirect Revascularization in a North American Cohort of Moyamoya Disease.

In adults with ischemic moyamoya disease (MMD), the efficacy of direct vs indirect revascularization procedures remains a matter of debate. To investigate the outcomes of ischemic MMD in a North American cohort treated by direct and indirect revascularizations. We retrospectively reviewed medical records of adult patients with MMD with ischemic presentation from 1984 to 2018 at the Brigham and Women's Hospital and Massachusetts General Hospital who underwent either direct or indirect bypasses. Early postoperative events and outcome at more than 6 mo postoperatively were evaluated using multivariable logistic regression analyses. Multivariable Cox proportional hazards regression analyses were used to evaluate delayed ischemic and hemorrhagic events. Analyses were performed per hemisphere. A total of 95 patients with MMD and 127 hemispheres were included in this study. A total of 3.5% and 8.6% of patients had early surgical complications in the direct and indirect bypass cohorts, respectively (P=.24). Hemispheres with direct bypasses had fewer long-term ischemic and hemorrhagic events at latest follow-up (adjusted hazard ratio [HR] 0.19, 95% confidence interval [CI] 0.058-0.63, P=.007; median follow-up 4.5 [interquartile range, IQR 1-8] yr). There was no difference between the direct and indirect bypass groups when the endpoint was limited to infarction and hemorrhage only (P=.12). There was no difference in outcome (modified Rankin Scale [mRS]≥3) between the 2 cohorts (P=.92). There was no difference in early postoperative events, long-term infarction or hemorrhage, or clinical outcome between direct and indirect revascularization. However, there was a significant decrease in all ischemic and hemorrhagic events combined in direct revascularizations compared to indirect revascularizations.

Risk factors for postoperative ischemic complications in pediatric moyamoya disease

BackgroundIschemic events are the most common postoperative complication in bypass surgery for moyamoya disease (MMD), but the risk factors for pediatric MMD remain unclear. The goal of the study was to investigate the risk factors for postoperative ischemic complications in pediatric MMD patients.MethodsWe retrospectively reviewed a consecutive series of pediatric MMD cases at Beijing Tiantan Hospital, Capital Medical University from June 2010 through June 2019. Preoperative clinical variables and radiographic findings were recorded, and logistic regression analysis was carried out to identify the risk factors for postoperative ischemic events.ResultsA total of 533 operations in 336 patients were included in this study. Postoperative complications occurred after 51 operations (9.6%), including 40/447 indirect bypass procedures, 9/70 direct bypass procedures, and 2/16 combined bypass procedures. Postoperative ischemic events were the most common complication and occurred in 30 patients after 31 procedures (8.9% per patient; 5.8% per operation), including 26/447 indirect bypass procedures, 4/70 direct bypass procedures, and 1/16 combined bypass procedures, and the incidence of these events did not differ significantly between indirect and non-indirect bypass (5.8% vs 5.8%; p = 0.999). Multivariate logistic regression analyses revealed that older age at operation (OR 1.129, 95% CI 1.011–1.260, p = 0.032) and posterior cerebral artery involvement (OR 2.587, 95% CI 1.030–6.496, p = 0.043) were significantly associated with postoperative ischemic events.ConclusionWe speculate that older age at operation and posterior cerebral artery involvement are risk factors for postoperative ischemic events in pediatric MMD patients.

Preoperative Risks of Cerebral Infarction in Pediatric Moyamoya Disease.

In pediatric moyamoya disease, there have been few reports of the risk factors for preoperative cerebral infarction, especially during the waiting period before surgery. The clinical and radiological findings of surgically treated pediatric moyamoya patients were evaluated to analyze the risk factors for cerebral infarction seen from onset to surgery. Between August 2003 and September 2019, 120 hemispheres of 71 patients under 18 years of age with moyamoya disease were surgically treated by direct and indirect bypass procedures. The mean age of all surgical hemispheres at diagnosis was 6.7±3.9 years (6 months–17 years). The potential risk factors for preoperative infarction were examined statistically. Multivariate logistic regression analysis showed that risk factors for infarction at the time of diagnosis were age at diagnosis (odds ratio [OR], 0.68 [95% CI, 0.57–0.82]; P<0.0001) and the magnetic resonance angiography (MRA) score (OR, 2.29 [95% CI, 1.40–3.75]; P=0.001). Univariate analysis showed that risk factors for infarction while waiting for surgery were age at diagnosis (OR, 0.61 [95% CI, 0.46–0.80]; P<0.0001), the MRA score (OR, 1.75 [95% CI, 1.26–2.41]; P=0.0003), and onset of infarction (OR, 40.4 [95% CI, 5.08–322.3]; P<0.0001). Multiple comparisons showed that patients under 4 years of age were at a significantly high risk of infarction at the time of diagnosis and while waiting for surgery. Time from diagnosis to surgery of >2 months was a significant risk factor for infarction while waiting for surgery in patients under 6 years of age. Young age at diagnosis and a high MRA score may be associated with rapid disease progression and result in preoperative infarction. We recommend that surgery be performed within 2 months of diagnosis for the patients under 4 years of age with a high MRA score (>5) and cerebral infarction. Further study is needed to define the optimal timing of surgery.

135 Direct and Combined Revascularization Versus Indirect Revascularization in the Treatment of Moyamoya Disease: A Systematic Review and Meta-Analysis

Abstract Introduction The goal of surgical revascularization of moyamoya disease (MMD) is to augment cerebral blood flow and prevent intracranial haemorrhage. This study aimed to compare direct and combined versus indirect bypasses with regard to perioperative complications in paediatric and adult patients with MMD, using a systematic review and meta-analysis of published observational studies. Method Primary outcome measures analysed included perioperative (30 days) complications. Results 20 studies reporting 2982 patients were eventually included. Pooled mean age was 37.5 years (95%CI: 33.5–41.5) and 7.4 years (95%CI: 4.1–10.7) in adult and paediatric patients, respectively. For adult patients, perioperative stroke rate was comparable between direct/combined and indirect bypass (OR = 1.26 [95%CI: 0.81–1.96], p = 0.300 for indirect). For paediatric patients, perioperative stroke rate was comparable between direct/combined and indirect bypass (OR = 2.43 [95%CI:0.74–7.94], p = 0.143 for indirect). No difference found in perioperative mortality between direct/combined and indirect bypass for adult patients (OR = 1.16 [95%CI:0.07–19.00], p = 0.915 for indirect). There was no difference in perioperative mortality between direct/combined and indirect bypass (OR = 1.39 [95%CI:0–Inf], p = 1.00 for indirect) in paediatric patients. Conclusions Both direct and indirect bypasses can be equally effective in preventing stroke, with similar rates of perioperative complications in paediatric and adult MMD patients.

Use of a panel of four microRNAs in CSF as a predicted biomarker for postoperative neoangiogenesis in moyamoya disease.

Introduction and AimsAt present, the treatment for moyamoya disease (MMD) primarily consists of combined direct and indirect bypass surgery. Nevertheless, more than half of indirect bypass surgeries fail to develop good collaterals from the dura and temporal muscle. This study aimed to investigate whether microRNAs (miRNAs) in cerebrospinal fluid (CSF) could serve as biomarkers for the prediction of postoperative collateral formation.MethodsMoyamoya disease patients with indirect bypass surgery were divided into angiogenesis and non‐angiogenesis groups, CSF was obtained, and miRNA sequencing was performed using the CSF. Candidate miRNAs were filtered and subsequently verified through qRT‐PCR. The diagnostic utility of these differential miRNAs was investigated by using receiver operating characteristic (ROC) curve analysis. Finally, the potential biological processes and signaling pathways associated with candidate miRNAs were analyzed using R software.ResultsThe expression levels of four miRNAs (miR‐92a‐3p, miR‐486‐3p, miR‐25‐3p, and miR‐155‐5p) were significantly increased in the angiogenesis group. By combining these four miRNAs (area under the curve [AUC] =0.970), we established an accurate predictive model of collateral circulation after indirect bypass surgery in MMD patients. GO and KEGG analyses demonstrated a high correlation with biological processes and signaling pathways related to angiogenesis.ConclusionThe 4‐miRNA signature is a good model to predict angiogenesis after indirect bypass surgery and help the surgeon to select a appreciate bypass strategy.

P44 Direct and Combined Revascularization Versus Indirect Revascularization in the Treatment of Moyamoya Disease: A Systematic Review and Meta-Analysis

IntroductionThere is currently no definite consensus regarding the surgical treatment of moyamoya disease (MMD). This study aimed to compare direct and combined versus indirect bypasses with regard to perioperative complications in pediatric and adult patients with MMD.MethodsSystematic searches of Medline, Embase and Cochrane Central were undertaken. Primary outcome measures analyzed included perioperative complications defined as any major adverse events within 30 days after bypass surgery.Results2490 studies were identified. 20 reporting 2982 patients were eventually included in our meta-analysis. Pooled mean age was 37.5 years (95%CI:33.5–41.5) and 7.4 years (95%CI:4.1–10.7) in adult and pediatric patients respectively. For adult patients, perioperative stroke rate was comparable between direct/combined bypass and indirect bypass (OR = 1.26 [95%CI:0.81–1.96], p = 0.300 for indirect bypass). For pediatric patients, perioperative stroke rate was comparable between direct/combined bypass and indirect bypass (OR = 2.43[95%CI:0.74–7.94], p = 0.143 for indirect bypass). No difference was found in perioperative mortality between direct/combined bypass and indirect bypass for adult patients (OR = 1.16[95%CI:0.07–19.00], p = 0.915 for indirect bypass). There was no difference in perioperative mortality between direct/combined bypass and indirect bypass (OR = 1.39 [95%CI:0 –Inf], p = 1.00 for indirect bypass) in pediatric patients. There was no significant difference in perioperative neurological deficit rates between direct/combined bypass and indirect bypass (OR = 1.27[95%CI:0.68–2.39], p = 0.451 for indirect bypass).Discussions/ConclusionsOur meta-analysis provides statistical evidence suggesting that both direct and indirect bypasses can be equally effective in preventing stroke, with similar rates of perioperative complications in pediatric and adult patients.

Encephaloduroarteriosynangiosis with Dural Inversion for Moyamoya Disease in a Pediatric and Adult Population—a Single-Center 20-Year Experience

Moyamoya disease refers to a progressive vasostenotic or vaso-occlusive disease that puts patients at risk for ischemic and/or hemorrhagic events. Surgical revascularization procedures aim to restore cerebral blood flow to mitigate stroke risk and functional decline. Direct and indirect bypass procedures have been proposed. Encephaloduroarteriosynangiosis (EDAS) with dural inversion is a well-accepted indirect procedure. Patients with moyamoya disease undergoing EDAS with dural inversion between 2000 and 2019 were retrospectively reviewed. Clinical data including short-term and long-term outcome were measured using the modified Rankin Scale. Patient satisfaction was assessed in patients with a minimum of 3 years of clinical follow-up. Over a 20-year period, 54 patients underwent 88 EDAS with dural inversion procedures. Most patients underwent bilateral surgery (34/54 patients, 63.0%). Median age at surgery was 19 years (range, 1-63 years) with a median follow-up of 6 years (range, 1-20 years). Periprocedural complications occurred in 4 of 54 patients (7.4%). Periprocedural infarction occurred in 3 of 88 operations (3.4%). Functional outcome at 90 days was favorable (modified Rankin Scale score 0-2) in 92.6% of cases. On long-term follow-up, 3 patients experienced ischemic infarction (5.6%), and 1 patient (1.9%) experienced hemorrhagic infarction. Patients' overall satisfaction with the surgical procedure at last follow-up was determined in 36 of 45 patients with at least 3 years of follow-up (response rate 80.0%). Median satisfaction was very good (score 5; range, 3-5). EDAS with dural inversion is a safe and effective indirect revascularization procedure for pediatric and adult moyamoya disease that is associated with favorable long-term outcomes and high patient satisfaction.

Changes in Surgical Treatment for Pediatric Moyamoya Disease

Pediatric patients with moyamoya disease frequently exhibit extensive cerebral infarction at the time of initial presentation and even in the early postoperative period. Cerebral infarctions are more frequent in younger patients. Surgical revascularization is the treatment of choice for patients with moyamoya disease. We modified surgical strategies for patients with moyamoya disease to reduce the incidence of postoperative cerebral infarction. Between January 2004 and December 2015, 46 patients (74 hemispheres) with moyamoya disease, aged ＜18 years, were surgically treated at our hospital. Surgical strategy entailed indirect bypass by encephalo-galeo-myo-duro-synangiosis (EGMDS) (3 hemispheres) for the first era, EGMDS and superficial temporal artery-middle cerebral artery (STA-MCA) single anastomosis (67 hemispheres) for the second era, and EGMDS and double STA-MCA anastomosis (4 hemispheres) for the third era. A review of clinical findings and radiological data showed that surgical treatment is effective for patients with moyamoya disease. Direct bypass can reduce the incidence of postoperative cerebral infarction, especially in younger patients. Postoperative cerebral infarctions were observed in 8 patients, all of whom were aged ＜6 years. Of these, 5 infarctions occurred in the ipsilateral hemisphere (6.8%) and 3 in the contralateral hemisphere (4.0%). Postoperative temporary neurological deficit due to hyperperfusion that had completely resolved by the time of discharge was seen in 9 hemispheres. Considering these results, direct bypass can induce immediate improvements in cerebral circulation that are suitable for patients with rapidly progressive moyamoya disease. However, direct bypass is not completely safe for pediatric patients with moyamoya disease because of the resulting changes in postoperative cerebral hemodynamics. To prevent such complications, we recently performed STA-MCA double bypass as an initial treatment for patients with a high risk of cerebral infarction that can increase cerebral perfusion in areas supplied by both the upper and lower trunks of the middle cerebral artery in a balanced manner. The outcome of this strategy was favorable.

Long-Term Patency and Final Structure After Superficial Temporal Artery–Middle Cerebral Artery Bypass Surgery: A Retrospective Study

To investigate long-term bypass patency and final structure for patients who underwent superficial temporal artery (STA)-middle cerebral artery (MCA) bypass. This study retrospectively evaluated 20 patients who underwent STA-MCA bypass and had 2-year follow-up with cerebral angiography. Patients were divided into internal carotid artery occlusion (n= 11) and MCA occlusion or stenosis (n= 9) groups, and diagnosis was either arteriosclerotic (n= 14) or nonarteriosclerotic (n= 6) disease. Final bypass formation was examined with cerebral angiography at 2 years postoperatively. Diameters of the STA, middle meningeal artery (MMA), and deep temporal artery (DTA) were measured at preoperative angiography and at 2-year follow-up. No significant differences in STA, MMA, and DTA diameters were reported between the internal carotid artery versus MCA group. For patients with arteriosclerotic disease, thicker STA diameters were noted on preoperative angiography. For patients with nonarteriosclerotic disease, MMA and DTA dilatation was noted on 2-year follow-up imaging. For patients with arteriosclerotic disease, all direct bypasses were patent at 2 years. For patients with nonarteriosclerotic disease, remarkable angiogenesis was demonstrated. Long-term patency of a direct bypass may be correlated with arteriosclerotic or nonarteriosclerotic etiology. An indirect bypass route may develop in patients with nonarteriosclerotic disease; therefore, it is important to create a foundation for an indirect bypass with MMA and DTA preservation during craniotomy. In 2 patients with nonarteriosclerotic disease, STA remained the primary bypass foundation; however, the technique resembled novel angiogenesis after encephaloduroarteriosynangiosis and not direct STA-MCA bypass. Therefore, final bypass structure might be affected by disease etiology.

Moyamoya: An Update and Review.

This article is a clinical review of Moyamoya disease (MMD) and Moyamoya syndrome (MMS). We review the incidence, epidemiology, pathology, historical context, clinical and radiographic findings, diagnostic imaging modalities, radiographic grading systems, the effectiveness of medical, interventional, and surgical treatment, and some of the nuances of surgical treatment options. This article will help pediatricians, neurologists, neurosurgeons, and other clinical practitioners who are involved in caring for patients with this rare clinical entity.MMD is an intrinsic primary disease process that causes bilateral progressive stenosis of the anterior intracranial circulation with the involvement of the proximal portions of the intracranial internal carotid artery (ICA) extending to involve the proximal portions of the anterior cerebral artery (ACA) and middle cerebral artery (MCA); posterior circulation involvement is very rare. This causes a compensatory response where large numbers of smaller vessels such as the lenticulostriate arteries begin to enlarge and proliferate, which gives the angiographic appearance of a "Puff of Smoke", which is translated into Japanese as "Moyamoya”. MMS is a secondary process that occurs in response to another underlying pathological process that causes stenosis of intracranial blood vessels, such as radiation. For example, an external source of radiation causes stenosis of the ICA with a compensatory response of smaller blood vessels, which then enlarge and proliferate in response and has the same "Puff of Smoke" appearance on the diagnostic cerebral angiogram (DCA).Histological findings include an irregular internal elastic lamina with luminal narrowing, hyperplasia of the tunica media, and intimal thickening with vacuolar degeneration in smooth muscle cells in the tunica media. Compensation for diminishing blood supply occurs through angiogenesis, which causes the proliferation and enlargement of smaller collateral blood vessels to increase blood supply to under-perfused areas of the brain.MMD is rare in the United States, with just 0.086 newly diagnosed cases per 100,000 individuals per year, which is approximately one per million new cases annually. Risk factors for MMD include Eastern Asian ancestry and predisposing conditions such as neurofibromatosis and Down's syndrome.Clinically, patients often present with stroke signs and symptoms from cerebral ischemia. The proliferation of collateral blood vessels within the basal ganglia can produce movement disorders. Catheter-based DCA is the current gold standard for obtaining a diagnosis. CT perfusion allows preoperative identification of ischemic vascular territories, which may be amenable to surgical intervention. MRI enables rapid detection of acute ischemic stroke using diffusion-weighted Imaging (DWI) and apparent diffusion coefficient (ADC) sequences to assess for any diffusion restriction. Non-contrast CT of the head is used to rule out acute hemorrhage in the presentation of a progressive neurological deficit.The treatment option for Moyamoya is generally surgical; medical treatment has failed to halt disease progression and neuro-interventional techniques such as attempted stenting of stenosed vessels have failed. Surgical options include direct and indirect cerebrovascular bypass.

Specific clinical features and one-stage revascularization surgery for moyamoya disease with severe cerebral ischemia in the territory of posterior cerebral artery.

There are no reports describing the surgical procedure for moyamoya disease (MMD) patients with severe cerebral ischemia in the territory of the posterior cerebral artery (PCA) at initial presentation. In this study, therefore, we describe their clinical and radiological features and clinical results of one-stage revascularization surgery for both anterior and posterior circulation. This study included 6 MMD patients who had severe cerebral ischemia in the PCA territory and underwent one-stage revascularization surgery for both anterior and posterior circulation. Of these, one patient underwent it on both sides. Their clinical and radiological data were precisely analyzed. Compared with usual procedure, craniotomy was extended towards the temporo-parietal area more widely. The parietal branch of superficial temporal artery (STA) was anastomosed to the angular or posterior temporal artery, while the frontal branch was anastomosed to the frontal branch of MCA. Ultimate indirect bypass was added. Their clinical and radiological outcomes were evaluated. Their neurological symptoms included visual and speech disturbance as well as numbness of the extremities. Cerebral infarct was distributed in the posterior temporal, parietal, and/or occipital lobe. Cerebral hemodynamics and metabolism were also impaired in the same regions. These findings were completely different from those in MMD patients without PCA lesion. Postoperative course was uneventful, and none of them recurred stroke during a mean follow-up period of 10.5 years. Surgical collaterals widely provided blood flow to the entire hemispheres, including the occipital lobe. Cerebral hemodynamics and metabolism markedly improved after surgery. One-stage revascularization surgery for both anterior and posterior circulation is feasible and effective to prevent future stroke in MMD patients with severe cerebral ischemia in the PCA territory at initial presentation.

Association between bilateral postoperative neoangiogenesis in patients with moyamoya disease

ObjectiveThe research on neoangiogenesis after indirect bypass for moyamoya disease (MMD) evaluated by using digital subtraction angiography (DSA) is limited. Our study objective was to investigate association of bilateral postoperative neoangiogenesis in patients with MMD. Patients and MethodsAll consecutive inpatients with MMD who received bilateral indirect bypass at Beijing Tiantan Hospital, Capital Medical University from January 2011 through December 2017 were screened. Bilateral neoangiogenesis was evaluated on lateral views and anteroposterior views by using DSA. ResultsTwenty-two patients (44 hemispheres) were included in this study. After a median 7.5 months DSA follow-up, on lateral views, 9 (40.9 %) hemispheres had grade A, 8 (36.4 %) hemispheres had grade B, and 5 (22.7 %) hemispheres had grade C after bypass on one side; 11 (50.0 %) hemispheres had grade A, 7 (31.8 %) hemispheres had grade B, and 4 (18.2 %) hemispheres had grade C after bypass on contralateral side. On anteroposterior views of ECA, 2 (9.1 %) hemispheres had level 0, 3 (13.6 %) had level 1, 6 (27.3 %) had level 2, and 11 (50.0 %) had level 3 after bypass on one side; 2 (9.1 %) hemispheres had level 0, 2 (9.1 %) had level 1, 6 (27.3 %) had level 2, and 12 (54.6 %) had level 3 after bypass on contralateral side. There was strong association between bilateral postoperative neoangiogenesis on lateral views (rs = 0.770; p = 0.000) and the anteroposterior views (rs = 0.548; p = 0.008). ConclusionsThere was strong association between bilateral postoperative neoangiogenesis. Postoperative neoangiogenesis on one side might predict the postoperative neoangiogenesis on the other side.

Moyamoya disease and moyamoya syndrome in Ireland: patient demographics, mode of presentation and outcomes of EC-IC bypass surgery.

There are no previously published reports regarding the epidemiology and characteristics of moyamoya disease or syndrome in Ireland. To examine patient demographics, mode of presentation and the outcomes of extracranial-intracranial bypass surgery in the treatment of moyamoya disease and syndrome in Ireland. All patients with moyamoya disease and syndrome referred to the National Neurosurgical Centre during January 2012-January 2019 were identified through a prospective database. Demographics, clinical presentation, radiological findings, surgical procedures, postoperative complications and any strokes during follow-up were recorded. Twenty-one patients were identified. Sixteen underwent surgery. Median age at diagnosis was 19years. Fifteen were female. Mode of presentation was ischaemic stroke in nine, haemodynamic TIAs in eight, haemorrhage in three and incidental in one. Sixteen patients had Moyamoya disease, whereas five patients had moyamoya syndrome. Surgery was performed on 19 hemispheres in 16 patients. The surgical procedures consisted of ten direct (STA-MCA) bypasses, five indirect bypasses and four multiple burr holes. Postoperative complications included ischaemic stroke in one patient and subdural haematoma in one patient. The median follow-up period in the surgical group was 52months; there was one new stroke during this period. Two patients required further revascularisation following recurrent TIAs. One patient died during follow-up secondary to tumour progression associated with neurofibromatosis type 1. Moyamoya is rare but occurs in Caucasians in Ireland. It most commonly presents with ischaemic symptoms. Surgical intervention in the form of direct and indirect bypass is an effective treatment in the majority of cases.

Achieving a Normal Perfusion State From Peroneal Bypass Impacts Limb Outcomes for Patients With Tissue Loss But Not Rest Pain

The peroneal artery is a well-established but indirect bypass target for treating chronic limb-threatening ischemia (CLTI). Attaining normal/near-normal foot perfusion after peroneal bypass remains possible with robust collateral flow. Here we evaluate the long-term limb outcomes of achieving optimal versus suboptimal foot perfusion after peroneal bypass in patients with CLTI.