Progressive Occlusion Research Articles

Modeling Fibrin Accumulation on Flow-Diverting Devices for Intracranial Aneurysms.

The mechanisms leading to aneurysm occlusion after treatment with flow-diverting devices are not fully understood. Flow modification induces thrombus formation within the aneurysm cavity, but fibrin can simultaneously accumulate and cover the device scaffold, leading to further flow modification. However, the interplay and relative importance of these processes are not clearly understood. A computational model of fibrin accumulation and flow modification after flow diversion treatment of cerebral aneurysms has been developed under the guidance of invitro experiments and observations. The model is based on the loose coupling of flow and transport-reaction equations that are solved separately by independent codes. Interaction or reactive terms account for thrombin production from prothrombin stimulated by thrombogenic metallic wires and inhibition by antithrombin as well as fibrin production from fibrinogen stimulated by thrombin and flow shear stress, and fibrin adhesion to device wires and already attached fibrin. The computational model was demonstrated and tested on idealized vessel and aneurysm geometries. The model was able to reproduce the salient features of fibrin accumulation after the deployment of flow-diverting devices in idealized invitro models of cerebral aneurysms. Namely, fibrin production in regions of high shear stress, initial accumulation at the inflow zone, and progressive occlusion of the device and corresponding flow attenuation. The computational model linking flow dynamics to fibrin production, transport, and adhesion can be used to investigate and better understand the effects that lead to fibrin accumulation and the resulting aneurysm inflow reduction and intra-aneurysmal flow modulation.

A ruptured craniocervical junction perimedullary arteriovenous fistula successfully treated through flow diversion: A case report

Background: Spinal arteriovenous fistulae (AVF) located at the craniocervical junction (CCJ) are rare and usually present with hemorrhage. Bleeding is usually attributed to arterial feeders arising from the anterior spinal artery (ASA) and aneurysms located on such feeders. Perimedullary AVFs are typically found on the ventral surface of the spinal cord, which makes them difficult to treat through traditional microsurgical methods. In addition, their unique vessel angioarchitecture frequently precludes safe embolization. We present the first case of a CCJ perimedullary AVF successfully treated using flow diversion. Case Description: A 76-year-old man was brought to the emergency department after suddenly losing consciousness. On further evaluation, infratentorial subarachnoid hemorrhage and a perimedullary AVF at the ventral surface of the spinal cord were identified. The ASA originated from the left V4 segment, providing a single feeder to the lesion associated with a 2 mm aneurysm. After initial antiplatelet loading, 8 hydrophilic polymer-coated flow diverters were deployed to cover the ASA’s origin in two sessions, achieving the complete occlusion of the lesion and the aneurysm 5 months later, without evidence of ischemic lesions. Conclusion: CCJ perimedullary AVFs can bleed with devastating consequences. These lesions can be challenging to treat through traditional microsurgical or endovascular techniques. Progressive occlusion with flow diversion is feasible in single-feeder AVFs, theoretically allowing blood flow reorganization to the cervical spinal cord.

Vascular Abnormalities and Neurofibromatosis Type 1: A Paediatric Case Series.

Neurofibromatosis type 1 (NF1) is a multisystemic neurocutaneous disease caused by a heterozygous mutation of the NF1 gene that encodes neurofibromin. Complications include vascular and neurologic abnormalities such as moyamoya syndrome, a cerebrovascular disorder with progressive occlusion of the large intracranial arteries, leading to ischemic events and the formation of abnormal vascular networks. Stenosis of the renal artery is another frequent complication of neurofibromatosis type 1, and it represents the most common cause of secondary hypertension in these patients. The purpose of the article is to describe the clinical manifestations of neurofibromatosis type 1 vasculopathy in 4 patients presenting with a wide range of neurologic and reno-vascular manifestations, as well as to examine current diagnostic management and follow-up, current therapeutic options, and to discuss further perspectives in terms of screening, diagnosis, and treatment.

8291 Graves’ Disease and Moyamoya Syndrome: A Complex Case of Thyroid Dysfunction and Neurovascular Abnormalities

Abstract Disclosure: A. Jamil: None. Q.V. Luong: None. A. Llorens Bonilla: None. A. Siddiqui: None. Background: Moyamoya disease is a cerebrovascular disease characterized by progressive stenosis and occlusion of cerebral arteries, particularly the internal carotid arteries, proximal anterior and middle cerebral arteries associated with a net-like collateral vessel formation. Moyamoya disease in association with certain systemic conditions (e.g. Graves’ disease, sickle cell anemia, neurofibromatosis type 1, and Down Syndrome) has been referred to as moyamoya syndrome. Graves’ disease is an autoimmune disease in which the development of thyroid-stimulating hormone (TSH) receptor autoantibodies leads to overproduction of thyroid hormones. Although the pathophysiology is unclear, Graves’ disease can adversely impact the clinical course of moyamoya syndrome.Clinical Case: A 26-year-old woman diagnosed with Graves’ disease at the age of 20 years who was in remission presented to the ED with right upper extremity weakness and headache. A stroke work-up was performed, and an initial CT head without contrast showed an acute infarct in the left temporal area. Extensive workup for hypercoagulability and cardiac causes were negative. MRI brain showed multiple infarcts of the left cerebral hemisphere with ivy sign, which are prominent linear or punctate high intensity areas in the subarachnoid space reflecting the development of collaterals that occurs in moyamoya disease. TSH at the time was noted to be <0.01 uIU/mL (range: 0.30-4.20 uIU/mL), indicating a thyrotoxic state. She was discharged on methimazole and antiplatelet therapies. However, the patient continued to have hypertension and headaches which did not resolve with the return to euthyroidism. At age 29, she again developed acute right upper and lower extremity weakness, and consequently presented to the ED. Imaging studies showed multiple punctate infarcts in her bilateral frontal lobes and bilateral ICA stenosis consistent with moyamoya disease. However, her biochemical studies showed euthyroidism. Ultimately, she underwent right frontotemporal craniotomy and direct parietal superficial temporal artery to middle cerebral artery bypass by neurosurgery to decrease her future stroke risk for her moyamoya syndrome, and her Graves’ disease remains in remission.Conclusions: The coexistence of Graves’ disease in moyamoya syndrome may suggest a pathophysiologic connection. It has been suggested that hemodynamic changes in cerebrovascular flow due to thyrotoxicosis might contribute to ischemic neurologic deficits. Surgical intervention for revascularization procedures should be attempted after optimal control of thyrotoxicosis, as this may help to prevent further ischemic events in the future and improve patient outcomes. Presentation: 6/1/2024

Superior Cerebellar Artery Aneurysm in a Case of Moyamoya Disease: A Rare Entity

AbstractMoyamoya disease is a rare condition characterized by progressive narrowing and occlusion of internal carotid artery and other major arteries of the brain with formation of multiple collaterals. The incidence of aneurysm in moyamoya disease is higher than normal population. Treating the simultaneous pathology of aneurysm and moyamoya disease in an individual is a rare entity. A 35-year-old male presented with headache, loss of consciousness, and generalized tonic-clonic seizure with subarachnoid hemorrhage. Digital Subtraction angiography showed moyamoya disease with left superior cerebellar artery aneurysm. Rupture of aneurysm was suspected to be the source of subarachnoid hemorrhage. Patient underwent clipping of the left superior cerebellar artery aneurysm with encephalo-duro-arterio-myo-synangiosis. Patient survived the procedures. All patients with subarachnoid hemorrhage in moyamoya disease should undergo angiogram and aneurysm should be looked for carefully. The site of aneurysm and the risk for damaging the collaterals should be kept in mind while planning the surgery in such cases.

Silent delayed middle cerebral artery occlusion post-mechanical thrombectomy: A case report

Mechanical thrombectomy (MT) for atherothrombotic lesions entails significant risks, including reocclusion and the possibility of worsening stenotic changes through endothelial injury. We treated a 45-year-old male admitted to our hospital with the sudden onset of left hemiparesis. Magnetic resonance imaging (MRI) revealed an occlusion of the right middle cerebral artery (MCA). Immediate intravenous tissue plasminogen activator infusion followed by MT successfully reperfused the MCA, although residual stenosis persisted in the distal portion of the M1 segment. Following the procedure, the patient’s symptoms resolved, and he was discharged. Three months later, follow-up MRI showed reocclusion of the right MCA and hemodynamic changes indicating reduced cerebral blood flow and cerebrovascular reactivity in the MCA territory. Subsequently, extracranial–intracranial bypass surgery was performed, and the patient did not develop any new symptoms postoperatively. While the patient in this case did not develop permanent symptoms, diligent observation is imperative following MT due to the potential for delayed progressive stenosis or occlusion.

Preliminary results of intracranial aneurysm treatment with derivo2heal embolization device

IntroductionThe Derivo 2 Heal Embolization Device (D2HED) is a novel flow diverter (FD) providing a fibrin-/heparin-based surface coating aiming at lower thrombogenicity. We evaluate periprocedural aspects and preliminary aneurysm occlusion efficacy for intracranial aneurysm treatment.MethodsThirty-four D2HEDs deployments (34 aneurysms, 32 patients) between 04/2021 and 10/2023 were analyzed. All patients were under dual antiplatelet therapy (dAPT). Periprocedural details, adverse events, and follow-up (FU) imaging were reviewed by consultant-level neuroradiologists. Complication rates and aneurysm occlusion efficacy are compared with performance data of other FDs based on literature research.ResultsEach intervention succeeded in the deployment of one D2HED. Significant and/or increased intraaneurysmal contrast stagnation immediately after D2HED deployment was seen in 73.5% of cases according to O’Kelly-Marotta (OKM) grading scale. Clinically relevant early adverse events occurred in three patients: Among them two cases with fusiform aneurysms in the posterior circulation (ischemic events, early in-stent-thrombosis) and one patient (ischemic event) out of the majority of 31 treated internal carotid artery aneurysms (3,2%). Regarding mid-term FU (> 165 days), one aneurysm did not show progressive occlusion presumably caused by a prominent A1 segment arising from the terminal ICA aneurysm itself. Apart from that, mid-term complete / partial occlusion rates of 80% / 20% could be demonstrated.ConclusionOur case series - although suffering from restricted sample size - suggests a potential effectiveness of D2HED in managing intracranial aneurysms. Further studies with larger samples are warranted to quantify long-term occlusion efficacy and the impact of antithrombogenic surface coating on the necessary (d)APT.

Long-term Safety and Efficacy of the Derivo Embolization Device in aSingle-center Series.

This study analyzes the long-term clinical and angiographic outcomes of the Derivo Embolization Device (DED), an advanced flow diverter device with an electropolished surface, for the treatment of intracranial aneurysms. Aconsecutive series of 101 patients (mean age: 58years, 72% female) treated with the DED for 122 aneurysms at asingle center between 2017 and 2023 was retrospectively analyzed for major (change in National Institutes of Health Stroke Scale [NIHSS] score ≥ 4points) and minor (change in NIHSS score < 4points) neurological events, procedural morbidity (increase of at least one point on the modified Rankin Scale), and angiographic results. There were 14(11%) recurrent aneurysms, 15(12%) ruptured aneurysms, 26(21%) posterior circulation aneurysms and 16(13%) fusiform or dissecting aneurysms. Device deployment failed in 1case (1%). Procedure-related symptomatic procedural complications consisted of 2(2%) major events (1major stroke and 1vessel perforation with intracranial hemorrhage and infarction) and 6minor events (6minor strokes). Procedural morbidity was 5%. There were no late ischemic or hemorrhagic events during follow-up. Complete and favorable aneurysm occlusion was achieved in 54% (40/74) and 62% (46/74) at amean of 5months, 71% (27/38) and 87% (33/38) at amean of 12months, and 76% (25/33) and 97% (32/33) at amean of 35months, respectively. The results demonstrate progressive aneurysm occlusion beyond 12months after DED implantation with an almost 100% favorable occlusion rate. Procedural morbidity was low and there were no late complications.

Endovascular Treatment of Intracranial Aneurysm: The Importance of the Rheological Model in Blood Flow Simulations.

Hemodynamics in intracranial aneurysm strongly depends on the non-Newtonian blood behavior due to the large number of suspended cells and the ability of red blood cells to deform and aggregate. However, most numerical investigations on intracranial hemodynamics adopt the Newtonian hypothesis to model blood flow and predict aneurysm occlusion. The aim of this study was to analyze the effect of the blood rheological model on the hemodynamics of intracranial aneurysms in the presence or absence of endovascular treatment. A numerical investigation was performed under pulsatile flow conditions in a patient-specific aneurysm with and without the insertion of an appropriately reconstructed flow diverter stent (FDS). The numerical simulations were performed using Newtonian and non-Newtonian assumptions for blood rheology. In all cases, FDS placement reduced the intra-aneurysmal velocity and increased the relative residence time (RRT) on the aneurysmal wall, indicating progressive thrombus formation and aneurysm occlusion. However, the Newtonian model largely overestimated RRT values and consequent aneurysm healing with respect to the non-Newtonian models. Due to the non-Newtonian blood properties and the large discrepancy between Newtonian and non-Newtonian simulations, the Newtonian hypothesis should not be used in the study of the hemodynamics of intracranial aneurysm, especially in the presence of endovascular treatment.

Incidence, prevalence, and treatment of Moyamoya disease in Japan: A population-based descriptive study

BackgroundMoyamoya disease (MMD) is characterized by progressive stenosis or occlusion of the terminal portions of the bilateral internal carotid arteries. A Japanese survey in 2003 reported an incidence and prevalence of MMD of 0.54 and 6.03 per 100,000 people, respectively, showing an upward trend over previous surveys. An update to these estimates is therefore warranted. Additionally, evidence is lacking on trends in revascularization and antiplatelet therapy in MMD patients. MethodsWe conducted a population-based descriptive study using a Japanese claims database. From fiscal year (FY) 2015 to 2019, we standardized the incidence and prevalence estimates of MMD to the 2015 Japanese census population by age and sex. We also estimated the 1-year cumulative incidence of revascularization among incident MMD patients and the proportion of prevalent MMD patients receiving antiplatelet therapy in each FY. ResultsThe age-standardized male-to-female ratio of both incident and prevalent MMD patients was approximately 1:2. Standardized incidence and prevalence of MMD per 100,000 population increased slightly from 1.8 to 2.4 and 14.7 to 17.6, respectively. The 1-year cumulative incidence of revascularization among incident MMD patients varied between 21.9 % and 28.9 %. Among prevalent MMD patients, 36.6 % to 39.0 % received antiplatelet therapy. ConclusionsThe incidence and prevalence of MMD in Japan from FY 2015 to 2019 were higher than those estimated in 2003. The trends in revascularization and antiplatelet therapy identified in this study will be useful in further improving the quality of MMD clinical practice.

De Novo Elastin Assembly Alleviates Development of Supravalvular Aortic Stenosis-Brief Report.

A series of incurable cardiovascular disorders arise due to improper formation of elastin during development. Supravalvular aortic stenosis (SVAS), resulting from a haploinsufficiency of ELN, is caused by improper stress sensing by medial vascular smooth muscle cells, leading to progressive luminal occlusion and heart failure. SVAS remains incurable, as current therapies do not address the root issue of defective elastin. We use SVAS here as a model of vascular proliferative disease using both human induced pluripotent stem cell-derived vascular smooth muscle cells and developmental Eln+/- mouse models to establish de novo elastin assembly as a new therapeutic intervention. We demonstrate mitigation of vascular proliferative abnormalities following de novo extracellular elastin assembly through the addition of the polyphenol epigallocatechin gallate to SVAS human induced pluripotent stem cell-derived vascular smooth muscle cells and in utero to Eln+/- mice. We demonstrate de novo elastin deposition normalizes SVAS human induced pluripotent stem cell-derived vascular smooth muscle cell hyperproliferation and rescues hypertension and aortic mechanics in Eln+/- mice, providing critical preclinical findings for the future application of epigallocatechin gallate treatment in humans.

Outcomes of surgical revascularization for pediatric moyamoya disease and syndrome

PurposeMoyamoya disease and syndrome represent rare entities characterized by progressive stenosis and/or occlusion of the intracranial blood vessels. We present our series of patients with moyamoya disease and syndrome stratified by underlying disease and analyze differences in presentation and outcome following surgical revascularization.MethodsThis was an Institutional Review Board (IRB) approved, retrospective review of all patients surgically revascularized by the senior author (SNM) while at Children’s National Hospital in Washington, DC. Demographic data, presenting symptoms and severity, surgical details, and functional and radiographic outcomes were obtained and analyzed for differences among the underlying cohorts of moyamoya disease and syndrome as well as by unilateral or bilateral disease and index or non-index surgeries.ResultsTwenty-two patients were identified with the following underlying diseases: six with idiopathic moyamoya disease, six with sickle cell anemia, five with trisomy 21, and five with neurofibromatosis type 1. Thirty hemispheres were revascularized with a significantly reduced rate of stroke from 3.19 strokes/year (SD = 3.10) to 0.13 strokes/year (SD = 0.25), p = 0.03. When analyzed by underlying cause of moyamoya syndrome, patients with neurofibromatosis type 1 were found to be significantly less likely than the other subtypes of moyamoya syndrome to have had either a clinical stroke (0.0% neurofibromatosis type 1 vs. 100.0% sickle cell, 60.0% trisomy 21, or 83.3% moyamoya disease, p < 0.01) or radiographic stroke (0.0% neurofibromatosis type 1 vs. 100.0% sickle cell, 60.0% trisomy 21, or 83.3% moyamoya disease, p < 0.01) at time of presentation. Patients with moyamoya syndrome associated with sickle cell disease were more likely to present with clinical and radiographic strokes. Additionally, patients with bilateral disease demonstrated no difference in final functional outcome compared to patients with unilateral disease (mRS 0.73 (SD = 1.33) vs. 1.29 (SD = 1.60), p = 0.63).ConclusionIndirect surgical revascularization decreases stroke risk for pediatric patients with different forms of moyamoya disease and moyamoya syndrome. Additionally, these data suggest that sickle cell anemia-associated moyamoya syndrome may represent a more aggressive variant, while neurofibromatosis type 1 may represent a more benign variant.

Angiopoietin-2 associates with poor prognosis in Moyamoya angiopathy.

Moyamoya angiopathy (MA) is a rare cerebrovascular disorder characterized by recurrent ischemic/hemorrhagic strokes due to progressive occlusion of the intracranial carotid arteries. The lack of reliable disease severity biomarkers led us to investigate molecular features of a Caucasian cohort of MA patients. The participants consisted of 30 MA patients and 40 controls. We measured cerebrospinal fluid (CSF) levels of angiogenic/inflammatory factors (ELISA). We then applied quantitative real-time PCR on cerebral artery specimens for expression analyses of angiogenic factors. By an immunoassay based on microfluidic technology, we examined the potential correlations between plasma protein expression and MA clinical progression. A RNA interference approach toward Ring Finger Protein 213 (RNF213) and a tube formation assay were applied in cellular model. We detected a statistically significant (p < 0.000001) up-regulation of Angiopoietin-2 (Ang-2) in CSF and stenotic middle cerebral arteries (RQ >2) of MA patients compared to controls. A high Ang-2 plasma concentration (p = 0.018) was associated with unfavorable outcome in a subset of MA patients. ROC curve analyses indicated Ang-2 as diagnostic CSF biomarker (>3741 pg/mL) and prognostic plasma biomarker (>1162 pg/mL), to distinguish stable-from-progressive MA. Consistently, MA cellular model showed a significant up-regulation (RQ >2) of Ang-2 in RNF213 silenced condition. Our results pointed out Ang-2 as a reliable biomarker mirroring arterial steno-occlusion and vascular instability of MA in CSF and blood, providing a candidate factor for patient stratification. This pilot study may pave the way to the validation of a biomarker to identify progressive MA patients deserving a specific treatment path.

Brain volume measured by synthetic magnetic resonance imaging in adult moyamoya disease correlates with cerebral blood flow and brain function

Moyamoya disease (MMD) is characterized by progressive arterial occlusion, causing chronic hemodynamic impairment, which can reduce brain volume. A novel quantitative technique, synthetic magnetic resonance imaging (SyMRI), can evaluate brain volume. This study aimed to investigate whether brain volume measured with SyMRI correlated with cerebral blood flow (CBF) and brain function in adult MMD. In this retrospective study, 18 adult patients with MMD were included. CBF was measured using iodine-123-N-isopropyl-p-iodoamphetamine single photon emission computed tomography. Cerebrovascular reactivity (CVR) to acetazolamide challenge was also evaluated. Brain function was measured using the Wechsler Adult Intelligence Scales (WAIS)-III/IV and the WAIS-R tests. Gray matter (GM), white matter, and myelin-correlated volumes were evaluated in six areas. Resting CBF was positively correlated with GM fractions in the right anterior cerebral arterial and right middle cerebral arterial (MCA) territories. CVR was positively correlated with GM fraction in the right posterior cerebral arterial (PCA) territory. Full-Scale Intelligence Quotient and Verbal Comprehension Index scores were marginally positively correlated with GM fractions in the left PCA territory. Processing Speed Index score was marginally positively correlated with GM fraction in the right MCA territory. The SyMRI-measured territorial GM fraction correlated with CBF and brain function in patients with MMD.

The natural history of aneurysms incompletely occluded by placement of a flow diverter: a multiinstitutional study.

Treatment of intracranial aneurysms by flow diversion is safe and effective and is increasingly popular. However, the correct treatment paradigm for aneurysms incompletely treated by initial placement of a flow diverter has not been established, nor have the subsequent natural history and occlusion rates of such aneurysms. The authors sought to outline the natural history of such aneurysms, which to date have been considered partially treated. The authors retrospectively reviewed consecutive cases from 6 high-volume neurointerventional services, including all cases in which the first follow-up imaging after placement of a flow diverter showed incomplete occlusion of the aneurysm, and for which subsequent clinical and/or radiological follow-up was available. All included patients were treated with the Pipeline Flex embolization device or the Pipeline Flex embolization device with Shield Technology. Subsequent radiographic and clinical outcome data were collected and analyzed using the Kaplan-Meier survival function. A total of 263 patients with persistently patent aneurysms on first follow-up imaging after flow diversion were identified. Of these, 204 had clinical follow-up and 152 had additional imaging follow-up. Of this final cohort, 148 aneurysms were unruptured, and 4 were ruptured. The average aneurysm size by maximum dimension was 10.8 mm. The average recorded follow-up was 27.8 months in the cohort, with some patients followed for as long as 9 years from treatment. Over the course of 403 person-years of follow-up, no delayed aneurysm ruptures were recorded. Both with and without retreatment, aneurysms showed a trend toward progressive occlusion over time. Complications related to device placement were low. Aneurysms that have been incompletely treated by flow diversion have a benign natural history with progression toward occlusion over time, with or without retreatment.

Acceleration of moyamoya disease after anti-vascular endothelial growth factor intravitreal injections

Abstract: Moyamoya disease (MMD) is a rare, progressive, irreversible vaso-occlusive disease affecting the cerebral vasculature. The progressive occlusion of blood vessels leads to the development of collateral vessels to compensate for the insufficient blood supply. Some growth factors such as vascular endothelial growth factor (VEGF) may cause excessive and aberrant angiogenesis in MMD. We report a case of a 55-year-old male, following up in retina clinics for diabetic retinopathy and macular edema who received anti-VEGF agents then he presented to the emergency room with left-sided face and body weakness, dysphagia, and dysarthria. Based on his clinical presentation and neuroimaging, he was diagnosed with moyamoya progression. We hypothesize that receiving anti-VEGF agents could have contributed to MMD progression in our patient and interfered with the collateral vessel development in a similar manner to their intended use in regressing neovascularization in diabetic retinopathy.

Unilateral Lung Removal in Combination with Monocrotaline or SU5416 in Rodents: A Reliable Model to Mimic the Pathology of the Human Pulmonary Hypertension.

Pulmonary hypertension (PH) is a chronic and progressive disorder characterized by elevated mean pulmonary arterial pressure, pulmonary vascular remodeling, and the development of concentric laminar intimal fibrosis with plexiform lesions. While rodent models have been developed to study PH, they have certain deficiencies and do not entirely replicate the human disease due to the heterogeneity of PH pathology. Therefore, combined models are necessary to study PH. Recent studies have shown that altered pulmonary blood flow is a significant trigger in the development of vascular remodeling and neointimal lesions. One of the most promising rodent models for increased pulmonary flow is the combination of unilateral left pneumonectomy with a "second hit" of monocrotaline (MCT) or SU5416. The removal of one lung in this model forces blood to circulate only in the other lung and induces increased and turbulent pulmonary blood flow. This increased vascular flow leads to progressive remodeling and occlusion of small pulmonary arteries. The second hit by MCT or SU5416 leads to endothelial cell dysfunction, resulting in severe PH and the development of plexiform arteriopathy.

Lateral medullary infarction in a patient with Moyamoya disease associated with RNF213 variants: a case report

Background: Moyamoya disease (MMD) is a rare cerebrovascular disease radiologically characterized by progressive bilateral occlusion of the distal portion of the internal carotid artery and compensating collaterals. Herein, we report a case of medullary infarction in a patient with MMD.Case Report: We present the case of a 54-year-old male with hypertension, hyperlipidemia, and unstable angina with sudden onset dysarthria and ataxia. Diffusion-weighted and T2-weighted images of magnetic resonance imaging showed a high-signal intensity lesion on the right lateral medulla, suggestive of acute infarction. Transfemoral cerebral angiography also demonstrated bilateral middle cerebral artery (MCA) occlusion. Testing of the ring finger protein 213 (RNF213) gene revealed a homozygous p.R4810K variant that was possibly associated with posterior circulation involvement.Conclusion: When the MCA is occluded in MMD, there is a possibility that medullary infarction may occur due to the mechanism of increased hemodynamic stress on the anastomotic posterior vessels.

Failure of Reconstructive Technique to Repair a Giant Intracranial Fusiform Aneurysm of the Basilar Artery: Case Report and Literature Review in the Pediatric Population

AbstractTreatment of giant basilar aneurysm presents a major treatment challenge, especially in the pediatric population. Morbidity and mortality approach 80 and 30%, respectively. Both reconstructive and deconstructive techniques are associated with high rates of complete occlusion and good neurological outcomes. We report a 14-year-old male with a giant basilar trunk aneurysm treated with an endovascular approach. Clinical symptoms began following an ischemic stroke 2 weeks prior to admission. Endovascular treatment was performed through a reconstructive technique by single flow diverter device (FDD) in the basilar artery; however, this technique failed. At 1-year follow-up, without additional endovascular treatment, the mid-basilar artery and aneurysm were occluded, with vertebrobasilar flow maintained through collaterals from the right posterior communicating artery. We present a challenging management of giant basilar aneurysm in a pediatric patient experiencing a failure of FDD deployment; however, we highlight the importance of collateral flow development in progressive occlusions.

Research progress on moyamoya disease combined with thyroid diseases.

Moyamoya disease (MMD), also known as abnormal cerebral vascular network disease, is characterized by progressive occlusion or stenosis of the internal carotid and cerebral arteries, as well as the formation of an abnormal cerebral vascular network. It can occur anywhere in the world but is most common in China, Japan, and the Republic of Korea. In recent years, there have been increasing reports on the coexistence of thyroid diseases and MMD, but the mechanism of their coexistence is still unclear. For this article, we used keywords such as "moyamoya disease", "thyroid", "Grave disease", "thyrotoxicosis", and "thyroid autoimmune antibodies" to search for 52 articles that met the requirements in medical databases such as PubMed and Web of Science. This article also reviews the research on the role of thyroid hormone, the mechanism of immune antibodies, the possible correlation between thyroid diseases and MMD disease genes, and the treatment methods, and discusses the possible relationship between MMD and thyroid diseases to provide a reference for the pathogenesis and treatment of MMD with thyroid diseases.