Indirect and direct revascularization of ACTA2 cerebral arteriopathy: feasibility of the superficial temporal artery to anterior cerebral artery bypass with posterior auricular artery interposition graft: case report

The interpositional bypass with a parietal branch of superficial temporal artery graft for symptomatic atherosclerotic anterior cerebral artery stenosis or occlusion

Background

For nonmoyamoya patients with anterior cerebral artery (ACA) stenosis or occlusion, whether direct revascularization of the ACA territory can prevent stroke is still unclear. The objective of this study was to investigate the efficacy and safety of a parietal branch of superficial temporal artery-interposed superficial temporal artery-to-ACA bypass (PISAB) for preventing stroke in patients with symptomatic atherosclerotic ACA stenosis or occlusion (SAASO).

Methods

We retrospectively analyzed the data from patients with SAASO who had undergone PISAB in our center between April 2016 and November 2021. The rates of patency, satisfaction (revascularization grades A and B) of bypass, perioperative complications, recurrence of ischemic stroke, changes in bypass flow, and improvements in cerebral blood perfusion were analyzed.

Results

A total of 19 SAASO patients were involved in this study. Sixteen out of 19 (84.2%) patients were free from any cerebral ischemic events after surgery. Only 3 patients (15.8%) had recurrent stroke postoperatively. Two (10.5%) surgery-related complications occurred, including hyperperfusion syndrome and minor stroke. No skin ischemic complications occurred. The average follow-up period was 50.6 ± 18.3 months. The flow rate of the bypass was significantly increased half a year after surgery (56.2 ± 8.0 mL/min vs. 44.3 ± 5.3 mL/min, p < 0.001). The ratio of ipsilateral/contralateral mean transit time in the superior frontal gyrus was decreased significantly after bypass (1.08 ± 0.07 vs. 1.23 ± 0.05, p < 0.001) and continued to decrease 6 months after surgery (1.05 ± 0.04 vs. 1.08 ± 0.07, p = 0.002). The patency rate of PISAB was 94.7% (18/19) 2 years after surgery. The satisfaction rate of bypass was 89.5% (17/19).

Conclusion

The results of this study indicate that PISAB, as a safe superficial bypass, can effectively reduce the risk of stroke in SAASO patients. More precise conclusions will require randomized control studies.

Neonatal diagnosis of ACTA2-related disease: A case report and review of literature

Multisystemic smooth muscle dysfunction syndrome (MSMDS, OMIM # 613834) is a rare autosomal dominant condition caused by pathogenetic variants of ACTA2 gene that result in impaired muscle contraction. MSMDS is characterized by an increased susceptibility to aneurismal dilatations and dissections, patent ductus arteriosus, early onset coronary artery disease, congenital mydriasis, chronic interstitial lung disease, hypoperistalsis, hydrops of gall bladder, and hypotonic bladder. Here, we report an early diagnosis of a MSMDS related to ACTA2 p.Arg179His (R179H) mutation in a newborn and performed a review of the literature. An early diagnosis of MSMDS is extremely important, because of the severe involvement of cardiovascular system in the MSMDS. Multidisciplinary care and surveillance and timely management of symptoms are important to reduce the risk of complications.

Nonsurgical treatment of cerebral ischemia associated with ACTA2 cerebral arteriopathy: a case report and literature review

Mutations in ACTA2 gene can lead to multisystemic smooth muscle dysfunction, including cerebrovascular disease. Treatment strategies for this rare entity remain controversial, and patients are at increasing risk of neurological sequelae. We herein present the case of an 11-year-old boy previously diagnosed with an ACTA2 gene mutation who developed repetitive transient ischemic attacks and treated with bosentan, an oral endothelin receptor antagonist. Magnetic resonance imaging revealed bilateral, periventricular white matter T2 hyperintensities, and magnetic resonance angiography identified several abnormalities including fusiform dilatation in the proximal segments of internal cerebral arteries, together with followed by terminal segmental stenosis. The distal branches showed a markedly straightened course with no increase in lenticulostriate collaterals. Magnetic resonance imaging also revealed an increase in the number and size of large periventricular white matter lesions located in the left frontal lobe with the progression of ischemic symptoms. Instead of revascularization surgery, the administration of bosentan was started due to the high risk of perioperative ischemic sequelae. After bosentan initiation, the patient's repetitive episodes of cerebral ischemia ceased, and there has been no increase in the number of white matter lesions for 7 years. Bosentan might be beneficial for treating cerebral ischemia associated with ACTA2 cerebral arteriopathy by maintaining the dilatation of stenotic vessels and adequate systemic blood flow and should be considered before performing revascularization surgery.

Triple bypass for multisystem smooth muscle dysfunction syndrome due to Arg179His ACTA2 mutation

Missense mutations in the smooth muscle-specific isoform of the alpha-actin (ACTA2) gene, which encodes smooth muscle actin, congenitally cause systemic smooth muscle dysfunction, leading to multiple systemic smooth muscle dysfunction syndrome. This disease is often diagnosed through the development of congenital mydriasis, patent ductus arteriosus, or thoracic aortic aneurysm at a young age. Some patients develop cerebrovascular lesions, also known as ACTA2 cerebral arteriopathy, which cause ischemic stroke and require surgical revascularization. However, an effective and safe treatment has not yet been established owing to the rarity of the disease. Furthermore, most reports of this disease involve children, with only a few reports on adults and few detailed reports on treatment outcomes published to date. We report a 46-year-old woman with ACTA2 cerebral arteriopathy caused by Arg179His, the most common mutation in this disease; she is the oldest patient reported with this disease to the best of our knowledge. The patient was diagnosed with multiple systemic smooth muscle dysfunction syndrome and ACTA2 cerebral arteriopathy after experiencing a stroke in the right cingulate gyrus. She underwent direct triple bypass with three anastomoses of the right superficial temporal artery to the middle and anterior cerebral arteries. She developed an ischemic stroke as a postoperative complication.The efficacy and safety of this procedure have not been clearly confirmed owing to the frailty of the donor superficial temporal artery and the poor development of collateral circulation; however, direct bypass should be considered a treatment option for patients experiencing progressive multiple strokes.

The Genetic Basis of Strokes in Pediatric Populations and Insight into New Therapeutic Options

Strokes within pediatric populations are considered to be the 10th leading cause of death in the United States of America, with over half of such events occurring in children younger than one year of life. The multifactorial etiopathology that has an influence on stroke development and occurrence signify the importance of the timely recognition of both modifiable and non-modifiable factors for adequate diagnostic and treatment approaches. The early recognition of a stroke and stroke risk in children has the potential to advance the application of neuroprotective, thrombolytic, and antithrombotic interventions and rehabilitation strategies to the earliest possible timepoints after the onset of a stroke, improving the outcomes and quality of life for affected children and their families. The recent development of molecular genetic methods has greatly facilitated the analysis and diagnosis of single-gene disorders. In this review, the most significant single gene disorders associated with pediatric stroke are presented, along with specific therapeutic options whenever they exist. Besides monogenic disorders that may present with stroke as a first symptom, genetic polymorphisms may contribute to the risk of pediatric and perinatal stroke. The most frequently studied genetic risk factors are several common polymorphisms in genes associated with thrombophilia; these genes code for proteins that are part of the coagulation cascade, fibrolysis, homocystein metabolism, lipid metabolism, or platelets. Single polymorphism frequencies may not be sufficient to completely explain the stroke causality and an analysis of several genotype combinations is a more promising approach. The recent steps forward in our understanding of the disorders underlying strokes has given us a next generation of therapeutics and therapeutic targets by which to improve stroke survival, protect or rebuild neuronal connections in the brain, and enhance neural function. Advances in DNA sequencing and the development of new tools to correct human gene mutations have brought genetic analysis and gene therapy into the focus of investigations for new therapeutic options for stroke patients.

Superficial Temporal Artery Extended Interposition Graft to Anterior Cerebral Artery Bypass for the Treatment of a Large Fusiform Distal Anterior Cerebral Artery Aneurysm: 2-Dimensional Operative Video

Fusiform aneurysms of the distal anterior cerebral artery (DACA) are infrequent. Clip reconstruction and sequential progressive clipping have been described in the management of giant thrombosed DACA aneurysms.1,2 Customized revascularization with bypass, side-to-side anastomosis, and trapping of the aneurysmal segment have also been performed for treating DACA aneurysms.3-12 We present a 2-dimensional operative video of superficial temporal artery (STA) to distal anterior cerebral artery bypass, followed by trapping of the aneurysm-bearing segment. A 57-yr-old lady presented with a large ruptured subcallosal fusiform DACA aneurysm (WFNS grade 1, Fisher grade 1). Angiography revealed a 1.3 × 0.9 cm fusiform aneurysm in the DACA.  Informed consent was secured from the patient and her family for the surgery and permission was obtained for the publication of the patient's image/surgical video. The frontal and parietal branches of the STA were dissected. The parietal branch was explanted and used as a free interposition graft between the frontal branch (end-to-end anastomosis) and calloso-marginal artery (end-to-side anastomosis). After confirming blood flow through the bypass using Doppler, the aneurysm was trapped and excised.  The patient had an uneventful recovery. Her postoperative computed tomography (CT) head revealed no evidence of neurological insult. The patency of the bypass conduit and the complete removal of the aneurysm were confirmed using a digital subtraction angiogram. Histopathological examination revealed an eccentric atheromatous plaque with a lipid core. There was no evidence of intraplaque hemorrhage. This extended STA graft utilizing the frontal and parietal branches of the STA, and its implantation into the distal ACA, offers a novel bypass strategy for tackling fusiform aneurysms of the DACA. Anastomosis to the calloso-marginal artery ensured perfusion of the ACA territory through the pericallosal artery during temporary occlusion.

Refractory cerebral infarction in a child with an ACTA2 mutation

INTRODUCTIONS

A specific mutation in the ACTA2 gene is known to cause multisystemic smooth muscle dysfunction syndrome, which is associated with cerebrovascular diseases and various organ disorders. Cerebral infarctions resulting from severe vasculopathy can be refractory; however, there are no previous reports describing the detailed clinical course of recurrent cerebral infarctions due to an ACTA2 mutation. Herein, we report a patient with an ACTA2 mutation who experienced multiple refractory cerebral infarctions in early childhood.

PATIENT DESCRIPTION

The patient was aged 1 year and 5 months at her first episode of cerebral infarction. Arteriopathy due to an ACTA2 mutation was diagnosed based on the characteristic cerebrovascular findings and abnormal physical findings, such as bilateral dilated pupils. Bilateral encephaloduroarteriosynangiosis and encephalogaleosynangiosis were performed after the first episode. Because the cerebral infarctions recurred postoperatively, administration of cilostazol followed by bosentan was started. However, despite these treatments she experienced seven cerebral infarctions by age 2 years and 6 months.

INTERPRETATION

Cerebral infarctions in patients with a specific ACTA2 mutation can occur even in early childhood, recur frequently, and cause severe motor and cognitive impairment. Physicians should be highly aware of this disease and be ready to provide the medical and surgical interventions necessary to minimize the disabling sequelae.

Failures in Revascularization for Pediatric Moyamoya Disease and Syndrome: A Scoping Review

BACKGROUND

Moyamoya disease (MMD) and moyamoya syndrome (MMS) are a rare cause of stroke commonly managed surgically. We conducted a scoping review to identify the current scope of the literature regarding factors associated with failure of revascularization surgery for MMD and MMS in pediatric patients and to catalyze future research.

METHODS

A scoping review was conducted to explore failures of revascularization surgery for MMD and MMS in pediatric patients using the PubMed, Embase, and Scopus databases. Titles and abstracts returned from searches were screened for full-text review. Studies meeting inclusion criteria were reviewed in full, and relevant data were extracted.

RESULTS

Of 2450 resultant articles, 15 were included. Angiographic outcomes were reported for 900 hemispheres, of which 442 (49.1%) were denoted as Matsushima grade A, 299 (33.2%) as Matsushima grade B, and 159 (17.7%) as Matsushima grade C. Patients with MMS had poorer angiographic outcomes than did patients with MMD. Patients with poor neovascularization had a greater degree of moyamoya vessels on follow-up angiogram. Suzuki stage was not associated with angiographic outcome in individual patients. Angiographic outcomes differed by surgical approach and were not associated with clinical outcomes. Literature identifying factors was sparse.

CONCLUSIONS

The existing literature indicates that factors such as cause, degree of moyamoya vessels, and surgical approach may affect the likelihood of Matsushima grade C revascularization in pediatric patients with MMD and MMS. Future studies are necessary to definitively elucidate factors associated with failure of revascularization surgery for pediatric MMD.

Cerebral arteriopathy in ACTA2 mutations: a spectrum of disease highlighted by a case of variable penetrance in two siblings

Until recently, cerebral arteriopathy due to heterozygous mutations of the ACTA2 gene was considered a variant of moyamoya disease. However, radiographic analysis of patients with these mutations reveals a distinctive angiographic appearance from that seen in moyamoya disease. Several heterozygous missense ACTA2 mutations have been implicated in the development of this distinct cerebrovascular entity; however, the penetrance and systemic manifestations of these mutations vary based on the location of the amino acid replacement within the α-smooth muscle actin protein. The severity of the phenotype may also differ among patients within a single mutation type. There is limited literature on the safety and efficacy of revascularization procedures for ACTA2 arteriopathy, which have been limited to those patients with known Arg179His mutations. The authors provide a review of the breadth of mutations within the ACTA2 literature and report a case of two siblings with de novo ACTA2 Arg258Cys mutations with differing clinical courses, highlighting the utility of indirect revascularization with 8-year follow-up data. This case highlights the importance of early recognition of the angiographic appearance of ACTA2 cerebral arteriopathy and performance of genetic testing, as the location of the mutation impacts clinical presentation and outcomes.

Direct double bypass using the posterior auricular artery as initial surgery for moyamoya disease: technical note

Surgical treatments for moyamoya disease (MMD) include direct revascularization procedures with proven efficacy, for example, superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, STA to anterior cerebral artery bypass, occipital artery (OA) to MCA bypass, or OA to posterior cerebral artery bypass. In cases with poor development of the parietal branch of the STA, the posterior auricular artery (PAA) is often developed and can be used as the bypass donor artery. In this report, the authors describe double direct bypass performed using only the PAA as the donor in the initial surgery for MMD.In the authors' institution, MMD is routinely treated with an STA-MCA double bypass. Some patients, however, have poor STA development, and in these cases the PAA is used as the donor artery. The authors report the use of the PAA in the treatment of 4 MMD patients at their institution from 2013 to 2016. In all 4 cases, a double direct bypass was performed, with transposition of the PAA as the donor artery. Good patency was confirmed in all cases via intraoperative indocyanine green angiography and postoperative MRA or cerebral angiography. The mean blood flow measurement during surgery was 58 ml/min. No patients suffered a stroke after revascularization surgery.

Neuroimaging of Pediatric Arteriopathies

Pediatric arteriopathies are increasingly recognized in school-aged children with a variety of presenting symptoms ranging from headache, seizures, encephalopathy, and neuropsychiatric symptoms as well as focal neurologic deficits due to acute ischemic strokes. However, unlike the adult stroke population, there are differences in the clinical manifestations, the stroke mechanism, and risk factors in pediatric ischemic stroke. There has been increasing awareness and recognition of pediatric cerebral arteriopathies as a predominant stroke etiology. Prompt diagnosis of arteriopathies is essential to limit injury and prevent recurrent stroke. Based on predominant vessels involved and clinical symptoms, these arteriopathies can be broadly divided into two categories: large-medium size arteriopathies and small vessel arteriopathies. Each category can be further divided into inflammatory and noninflammatory according to their etiologies. The ability to distinguish between inflammatory and noninflammatory etiologies carries major prognostic implications for acute management and secondary stroke prevention as well as screening for systemic complications and counseling.

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.

Recent developments and new frontiers in childhood arterial ischemic stroke

This review will discuss important developments in childhood arterial ischemic stroke over the past decade, focusing on improved understanding of the causes, consequences, and targets for intervention. Risk factors for childhood arterial ischemic stroke are different to adults. Infections, particularly herpes group viruses, are important precipitants for stroke. Non-atherosclerotic arteriopathies are the most common cause of childhood arterial ischemic stroke and an important predictor of recurrent events. Recent advances include the identification of serum biomarkers for inflammation and endothelial injury, and imaging biomarkers to monitor for vascular progression. Multicenter trials of immunotherapies in focal cerebral arteriopathies are currently in development. Recognition of clinical and radiological phenotypic patterns has facilitated the discovery of multisystem disorders associated with arterial ischemic stroke including ACTA2 arteriopathy and adenosine deaminase 2 deficiency. Identification of these Mendelian disorders provide insights into genetic mechanisms of disease and have implications for medical and surgical management. In contrast to adults, there are long diagnostic delays in childhood arterial ischemic stroke. Refinement of pediatric Code Stroke protocols and clinical decision support tools are essential to improve diagnostic certainty and improve access to reperfusion therapies. Children do not recover better than adults following arterial ischemic stroke, with more than half of survivors having long-term impairments. The physical, cognitive, and behavioral consequences of childhood arterial ischemic stroke are increasingly reported but further research is required to understand their impact on participation, quality of life, psychosocial, and family functioning. Longitudinal studies and the use of advanced imaging techniques, to understand neurobiological correlates of functional reorganization, are essential to developing targeted intervention strategies to facilitate recovery.