Moyamoya angiopathy: early postoperative course within 3 months after STA–MCA–bypass surgery in Europe—a retrospective analysis of 64 procedures

Is STA really a low‐flow graft? A quantitative ultrasonographic study of the flow of STA for cerebral revascularization in MMD patients

OBJECTIVE

Direct revascularization remains an important tool in the treatment of patients with Moyamoya disease (MMD). The superficial temporal artery (STA) is the most commonly used donor vessel for direct bypass, and an STA graft has traditionally been considered a low-flow graft for flow augmentation. This study aimed to quantitatively evaluate the blood flow of the STA after direct revascularization.

METHODS

All direct revascularization procedures performed between 2018 and 2021 by one experienced neurosurgeon were screened. Quantitative ultrasound was used to measure the flow data of the patient's bilateral parietal branch of the STA(STA-PB), the bilateral frontal branch of the STA(STA-FB), and the left radial artery. Data on the patients' basic information, Suzuki grade, Matsushima type, anastomosis type, and blood biochemical parameters were collected and analyzed using univariate and multivariate models. An MBC Scale scoring system was proposed to evaluate the recipient artery network of the middle cerebral artery (MCA) tree. The relationship between MBC Scale score and STA graft flow was statistically analyzed.

RESULTS

In total, 81 patients (43 males and 38 females) successfully underwent STA-MCA bypass and were included in this study. The mean flow rates in the STA-PB graft on 1 day preoperatively, 1 day postoperatively, 7 days postoperatively, and >6 months postoperatively (long-term) were 10.81, 116.74, 118.44, and 56.20 mL/min respectively. Intraoperative graft patency was confirmed in all patients. Comparing the preoperative and all postoperative time points, the STA-PB flow rates were statistically significant (p < 0.001). The MCA-C score was significantly associated with postoperative flow rate on day 1 (p = 0.007).

CONCLUSION

The STA is a useful donor artery for direct revascularization inpatients with MMD and can provide sufficient blood supply to the ischemic cerebral territory.

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.

Arterial spin labeling for moyamoya angiopathy: A preoperative and postoperative evaluation method

Objectives

Studies have shown that arterial spin labeling (ASL) effectively replaces traditional MRI perfusion imaging for detecting cerebral blood flow (CBF) in patients with Moyamoya angiopathy (MMA). However, there are few reports on the relationship between neovascularization and cerebral perfusion in patients with MMA. The aim of this study is to investigate the effects of neovascularization on cerebral perfusion with MMA after bypass surgery.

Methods

We selected patients with MMA in the Department of Neurosurgery between September 2019 and August 2021 and enrolled them based on the inclusion and exclusion criteria. ASL imaging was used to monitor the baseline CBF level before surgery and determine the changes in cerebral vessels at postoperative 1 week and 6 months, respectively. The Alberta stroke grade, modified Rankin Scale (mRS), and digital subtraction angiography images were used to evaluate the effect of postoperative CBF status and prognosis. Ninety hemispheres from 51 patients were included in this study. There were no significant differences in the baseline data of the enrolled patients. At 1 week and 6 months post-surgery, the CBF state in the operation area was significantly changed compared with that at baseline (P < 0.05). The preoperative Alberta score (t = 2.714, P = 0.013) and preoperative mRS score (t = 6.678, P < 0.001) correlated with postoperative neovascularization.

Conclusion

ASL is an effective method for detecting CBF and plays an important role in the long-term follow-up of patients with MMA. Combined cerebral revascularization significantly improves CBF in the operation area both in the short and long terms. Patients with lower preoperative Alberta scores and higher mRS scores were more likely to benefit from combined cerebral revascularization surgery. However, regardless of the type of patient, CBF reconstruction can effectively improve prognosis.

Microembolic signals and antiplatelet therapy in Moyamoya angiopathy

BACKGROUND

Embolism as a cause of stroke is widely neglected in Moyamoya angiopathy (MMA), and recommendations for use of antiplatelet therapy (APT) vary. We examined the presence of microembolic signals (MES) during transcranial Doppler (TCD) monitoring and assessed the effects of APT on the occurrence of MES in MMA.

PATIENTS AND METHODS

We retrospectively analysed patients with MMA treated at our centre between 2011 and 2021. TCD was performed at first presentation and at most visits, while number of visits varied between individual patients. TCD was performed for 30 min bilaterally. Patient demographics, vascular risk factors, and antiplatelet treatment were collected from each clinic visit and ischemic and haemorrhagic episodes were captured as recorded during follow-up visits.

RESULTS

209 patients were included in the analysis (mean age 38.7 ± 15.3, 28% male). 21 patients with 27 MES-positive TCD examinations were identified (10%). Patient characteristics were similar in MES-positive and MES-negative groups. However, recent ischemic events were detected at a significantly higher rate in MES-positive patients (42.9% vs 4.8%, p < 0.001). After MES detection, change of antiplatelet drug regime was performed, leading to loss of MES in all cases. Dual APT was preferably used in the MES-positive group (p < 0.001) but no significant difference of haemorrhage during follow-up-visits was observed. Reduction of APT before bypass-surgery triggered MES in four patients.

CONCLUSION

APT is required in patients with MMA. MES monitoring may help to identify risk patients in need of intensified APT.

Cutaneous manifestations in Moyamoya angiopathy: A review

BACKGROUND AND PURPOSE

Moyamoya angiopathy (MA) is a progressive cerebrovascular disease with a poorly understood pathophysiology. It is mainly characterized by progressive bilateral stenosis of the terminal intracranial part of the supraclinoid internal carotid arteries and the proximal parts of the middle and anterior cerebral arteries. This results in early-onset ischemic or hemorrhagic strokes. The disease may be idiopathic (known as Moyamoya disease) or associated with other heritable or acquired conditions, including type 1 neurofibromatosis or other RASopathies, sickle cell disease, Down syndrome, or autoimmune disorders (known as Moyamoya syndrome). Apart from the brain, other organ manifestations including cutaneous ones have also been described in MA patients.

MATERIALS AND METHODS

A literature research on PubMed was performed for articles mentioning the cutaneous association in MA and published between 1994 and October 2020.

CONCLUSION

The present review summarizes the cutaneous associations as well as the coincidental dermatological findings seen in MA patients. Those include changes in the epidermis, dermis, or skin appendages for example café-au-lait spots, hypomelanosis of Ito, livedo racemosa, hemangiomas, premature graying of hair, chilblains etc.

Capillary microscopy in Europeans with idiopathic Moyamoya angiopathy

OBJECTIVE

In Europe, MMA is a very rare non-inflammatory vasculopathy. MMA is an important differential diagnosis of cerebral vasculitis. Systemic manifestations, such as livedo racemosa or renal artery stenosis, associated with Moyamoya variants suggest the involvement also of non-cerebral vessels. Hypothetically, capillary microscopy could be a promising non-invasive screening method to visualize microcirculation, for example prior to cerebral angiography.

METHODS

Standardized capillary microscopic images were taken in European patients with MMA and subsequently evaluated in a blinded analysis, using data obtained from a large NP cohort and a large SLE cohort by the same blinded Investigator as controls.

RESULTS

Twenty-four European MMD patients and 14 healthy accompanying controls were included in this study. The results were compared to 116 SLE patients and 754 NP subjects. In MMD patients, no capillary morphological differences were found in comparison with NP, in particular no density reduction or increased neoangiogenesis. The pattern observed in the SLE cohort was clearly distinct from NP and MMD with regard to vascular density, vascular damage, and neoangiogenesis.

CONCLUSIONS

MMD is not associated with microvascular changes of the nailfold capillaries. In this respect, it is clearly distinct from SLE.

High variance of intraoperative blood pressure predicts early cerebral infarction after revascularization surgery in patients with Moyamoya disease

Few studies focused on the intraoperative blood pressure in Moyamoya disease (MMD) patients. We aimed to clarify whether or not it relates to early cerebral infarction after revascularization. We reviewed a retrospective cohort of Moyamoya disease from 2011 to 2018 in Beijing Tiantan Hospital, and patients with radiologically confirmed early postoperative infarction were included in the analysis. Controls were matched based on age, sex, and revascularization modality at a ratio of 1:5. Perioperative clinical factors and intraoperative blood pressure data were collected and analyzed. A total of 52 patients out of 1497 revascularization surgeries (3.5%) who experienced CT or MRI confirmed early postoperatively cerebral infarction, aged 38.46 ± 11.70; 26 were male (50.0%). Average real variability (ARV)-systolic blood pressure (SBP) (OR 3.29, p = 0.003), ARV-diastolic blood pressure (DBP) (OR 4.10, p = 0.005), ARV-mean arterial pressure (MAP) (OR 4.08, p = 0.004), and the maximum drops of DBP (OR 1.08, p = 0.003) and MAP (OR 1.06, p = 0.004) were associated with early postoperative infarction. In patients who experienced massive cerebral infarction, the maximum drops of DBP (OR 1.11, p = 0.004) and MAP (OR 1.11, p = 0.003) are independent risk factors, whereas ARVs of SBP (OR 3.90, p < 0.001), DBP (OR 4.69, p = 0.008), and MAP (OR 4.72, p = 0.003) are significantly associated with regional infarction. High variance of intraoperative blood pressure and drastic blood pressure decline are independent risk factors for postoperative infarction in MMD patients who underwent revascularization surgery. Maintaining stable intraoperative blood pressure is suggested to prevent early postoperative cerebral infarction in MMD patients.

Clinical importance of the superficial temporal artery in neurovascular diseases: A PRISMA-compliant systematic review

The superficial temporal artery (STA) plays a very important role in neurovascular diseases and procedures. However, until now, no comprehensive review of the role of STA in neurovascular diseases from a neurosurgical perspective has ever been published. To review research on the clinical importance of STA in neurovascular diseases, a literature search was performed using the PubMed database. Articles were screened for suitability and data relevance. This paper was organized following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. According to the literature, STA is one of the terminal branches of the external carotid artery and can give off scalp, muscle, and transosseous branches. STA-middle cerebral artery (MCA) bypass is very useful for intracranial ischemic diseases, including moyamoya disease, chronic ICA and MCA insufficiency, and even acute ischemic stroke. For intracranial complex aneurysms, STA bypass remains a major option that can serve as flow replacement bypass during aneurysmal trapping or insurance bypass during temporary parent artery occlusion. Occasionally, the STA can also be involved in dural AVFs (DAVFs) via to its transosseous branches. In addition, the STA can be used as an intraoperative angiography path and the path to provide endovascular treatments. Therefore, STA is a very important artery in neurovascular diseases.