Personalised stroke evaluation and management: tailoring individualised patient care for hereditary haemorrhagic telangiectasia.

SummaryHereditary haemorrhagic telangiectasia (HHT) has an estimated prevalence of 1 in 5000-8000 individuals globally with pulmonary arteriovenous malformations (PAVMs) affecting approximately 15%-50% of HHT patients. Ischaemic stroke is a known complication of PAVMs that affects ≤30% of patients with PAVMs. Studies have shown that patients with PAVMs have ischaemic stroke a decade earlier than routine stroke. The predominant mechanism of ischaemic stroke in HHT patients is paradoxical embolism due to PAVMs, but most HHT-related PAVMs are asymptomatic. Additionally, HHT is often underdiagnosed in patients and poses a challenge to physicians due to its rarity. We present a case of a patient with ischaemic stroke who was subsequently diagnosed with HHT and found to have a PAVM on further evaluation. This case highlights the importance of using an individualised patient-centred stroke evaluation and screening for PAVMs in patients who had a stroke with possible or suspected HHT and definite HHT.

Elucidating the pathogenesis behind arteriovenous malformations of the central nervous system: a bibliometric analysis.

Arteriovenous malformations (AVMs) are vascular malformations of the central nervous system (CNS) with potential for significant consequences. The exact pathophysiologic mechanism of AVM formation is not fully understood. This study aims to evaluate bibliometric parameters and citations of the literature of AVMs to provide an overview of how the field has evolved. We performed an electronic search on Web of Science to identify the top 100 published and indexed articles with the highest number of citations discussing the pathogenesis of AVMs. This study yielded 1863 articles, of which the top 100 were selected based on the highest total citation count. These articles included 24% basic science, 46% clinical, and 30% review articles. The most-cited article was a clinical article from 2003, and the most recent was published in 2022. The median number of authors was 6, with the highest being 46 for a clinical article. The top 5 journals were identified, with the highest impact factor being 20.1. 13 countries were identified, with the US contributing the most articles (approximately 70%). Regarding genes of investigation, VEGF was one of the early genes investigated, while more interested in RAS/MAPK has been garnered since 2015. There is a growing interest in AVM genomics and pathogenesis research. While progress has been made in understanding clinical aspects and risk factors, the exact pathophysiological mechanisms and genetic basis of AVM formation remain incompletely understood. Further investigation of key genes in AVM pathogenesis can allow identification of potential therapeutic targets.

Microsurgical Treatment for Arteriovenous Malformations in the Hand.

Vascular malformations in the extremities are a common site of occurrence; arteriovenous malformations (AVMs) are the least frequent of all vascular malformations, estimated at 5% to 20%. The first step in management is to perform a thorough clinical examination. Symptoms are assessed, and staging is performed using the Schobinger classification. Next, ultrasonography and contrast-enhanced computed tomography are used to confirm the diagnosis of AVM and to confirm the extent of the malformation. Surgery is the first-line treatment and reconstruction is performed. In cases where surgery is not feasible, embolization and sclerotherapy may be used to alleviate symptoms.

Surgical Treatment of Spontaneous Superficial Temporal Artery Arteriovenous Malformation: A Case Report.

BACKGROUND An arteriovenous malformation (AVM) is an abnormal connection between an artery and a vein, bypassing the capillary network. An AVM of the superficial temporal artery (STA) can occur after trauma, iatrogenic injury, infection, or spontaneously. Spontaneous, or iatrogenic, presentations of STA AVM are thought to be rare, with very few reported cases. Symptoms include local pain, headache, tinnitus, or paresthesia, in addition to a palpable mass associated with thrill on palpation. Options for diagnosis include intra-arterial angiography, doppler ultrasound, magnetic resonance angiography (MRA), and computed tomography angiography (CTA). Current management options include surgical excision, ligation, and embolization; however, it is unknown which treatment is superior in terms of recurrence and which carries a lower risk of complications. CASE REPORT We present a case of a spontaneous STA AVM in a 76-year-old woman with past medical history significant for seasonal allergies and hyperlipidemia, who presented with pulsatile tinnitus and a palpable, tender mass located to the left temporal area. The mass had been present for several years, with gradual increase in size two to three years prior to presentation. She denied any history of trauma or procedure prior to presentation of the pulsatile mass. She underwent open excision with complete resolution of symptoms and no recurrence at 11-month follow-up. CONCLUSIONS AVM of the STA is a condition that can occur secondary to trauma, infection, iatrogenic injury, or spontaneously. Spontaneous, or iatrogenic, presentations of STA AVM are thought to be rare, with very few cases documented in the literature. Surgical treatment remains the standard of management, with options including surgical excision, ligation, or embolization.

Scalp arteriovenous malformations - 20 years of experience in a tertiary healthcare centre.

BACKGROUND: Scalp arteriovenous malformations (SAVM) are extremely uncommon vascular malformations, with only ~200 cases published in the English language in the past years. The objective of the present study was to describe the experience of a single reference service in neurosurgery. METHODS: This is a descriptive and retrospective study conducted at our institution, which included cases of SAVM treated between 2001 and 2022. All information were extracted from the medical records of our institution. Patient confidentiality was preserved. Furthermore, an illustrative case has been described in detail. RESULTS: Seven patients were included. The male-to-female ratio was 2.5: 1 and the mean age was 23.3 (3-42) years. Most cases (56.4%) were spontaneous and the lesions were located in the frontal (28.7%) and parietal (28.7%) regions. All lesions were supplied by more than one feeder, with the superficial temporal and occipital arteries being the most commonly involved (71.5%). Six patients underwent preoperative embolization, and 56.4% patients had scalp necrosis. Five patients underwent surgical resection, all without recurrence and with good postoperative evolution. CONCLUSIONS: More than one artery was involved in all cases, and the properties of the involved vessel influences the approach strategy. Surgical treatment is curative, and preoperative embolization helps reduce bleeding during the surgery. Complete resection of the lesions prevents associated complications, such as bleeding or recurrence. Scalp necrosis is a frequent complication in the treatment of these lesions, and a multidisciplinary approach involving reconstructive plastic surgery should always be considered.

Macrocheilia as an Atypical Clinical Presentation of Capillary Malformation-Arteriovenous Malformation Type 2.

This case report describes a 53-year-old man with multiple erythematous macules and papules diffusely distributed on the frontal area, cheeks, eyelids, nose, and supralabial skin.

Hereditary hemorrhagic telangiectasia: from signaling insights to therapeutic advances.

Hereditary hemorrhagic telangiectsia (HHT) is an inherited vascular disorder with highly variable expressivity, affecting up to 1 in 5,000 individuals. This disease is characterized by small arteriovenous malformations (AVMs) in mucocutaneous areas (telangiectases) and larger visceral AVMs in the lungs, liver, and brain. HHT is caused by loss-of-function mutations in the BMP9-10/ENG/ALK1/SMAD4 signaling pathway. This Review presents up-to-date insights on this mutated signaling pathway and its crosstalk with proangiogenic pathways, in particular the VEGF pathway, that has allowed the repurposing of new drugs for HHT treatment. However, despite the substantial benefits of these new treatments in terms of alleviating symptom severity, this not-so-uncommon bleeding disorder still currently lacks any FDA- or European Medicines Agency-approved (EMA-approved) therapies.

Shear Stress and Sub-Femtomolar Levels of Ligand Synergize to Activate ALK1 Signaling in Endothelial Cells.

Endothelial cells (ECs) respond to concurrent stimulation by biochemical factors and wall shear stress (SS) exerted by blood flow. Disruptions in flow-induced responses can result in remodeling issues and cardiovascular diseases, but the detailed mechanisms linking flow-mechanical cues and biochemical signaling remain unclear. Activin receptor-like kinase 1 (ALK1) integrates SS and ALK1-ligand cues in ECs; ALK1 mutations cause hereditary hemorrhagic telangiectasia (HHT), marked by arteriovenous malformation (AVM) development. However, the mechanistic underpinnings of ALK1 signaling modulation by fluid flow and the link to AVMs remain uncertain. We recorded EC responses under varying SS magnitudes and ALK1 ligand concentrations by assaying pSMAD1/5/9 nuclear localization using a custom multi-SS microfluidic device and a custom image analysis pipeline. We extended the previously reported synergy between SS and BMP9 to include BMP10 and BMP9/10. Moreover, we demonstrated that this synergy is effective even at extremely low SS magnitudes (0.4 dyn/cm2) and ALK1 ligand range (femtogram/mL). The synergistic response to ALK1 ligands and SS requires the kinase activity of ALK1. Moreover, ALK1's basal activity and response to minimal ligand levels depend on endocytosis, distinct from cell-cell junctions, cytoskeleton-mediated mechanosensing, or cholesterol-enriched microdomains. However, an in-depth analysis of ALK1 receptor trafficking's molecular mechanisms requires further investigation.

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia.

OBJECTIVE: Brain arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) present different characteristics from sporadic AVMs, and they have lower initial bleeding rates. Conservative management is usually preferred for the treatment of these lesions. In this case study, we present the largest series of HHT patients treated with stereotactic radiosurgery to date. METHODS: We identified eight patients with HHT and 14 AVMs. We retrospectively collected clinical, radiographic, and treatment characteristics of the patients and each AVM. RESULTS: Most patients in our sample presented with small AVMs. The median volume of these AVMs was 0.22 cm3 (IQR 0.08-0.59). Three out of eight patients presented with initial intracerebral hemorrhage (ICH). The majority of lesions had low (12/14) Spetzler-Martin grades (I-II). Median maximum and margin doses used for treatment were 36.2 (IQR 35.25-44.4) and 20 (IQR 18-22.5) Gy, respectively. The overall obliteration rate after SRS was 11/14, and the median time to obliteration across all 11 obliterated AVMs was 35.83 months (IQR, 17-39.99). Neurological status was favorable with all patients having a mRS of 0 or 1 at the last follow-up. Symptomatic radiation-induced changes (RIC) after SRS were low (7.1%), and there were no permanent RIC. CONCLUSIONS: Patients with HHT who present with multiple brain AVMs are generally well served by SRS. Obliteration can be achieved in the majority of HHT patients and with a low complication rate. In the current study, initial hemorrhage rates prior to SRS were noticeable which supports the decision to treat these AVMs. Future studies are needed to better address the role of SRS for HHT patients harboring ruptured and unruptured AVMs.

Fetal choroid plexus arteriovenous malformation, masquerading as a neoplastic lesion.

A woman in her 20s, who was pregnant, underwent a routine antenatal ultrasound revealing organised intraventricular haemorrhage and a vascular area in the left thalamic region. Fetal MRI raised suspicion of arteriovenous malformation (AVM). The baby was delivered at 36 weeks via C-section, and initial brain MRI suggested a possible neoplastic lesion.Cerebral angiography confirmed a large AVM involving the left choroid plexus with arterial feeders from the left anterior and posterior choroidal arteries and a large venous varix draining into the vein of Galen. Both arterial feeders were successfully embolised with Onyx and glue, achieving complete occlusion.Choroid plexus AVMs are rare and often lead to intraventricular or intraparenchymal haemorrhage. Surgical treatment has shown success, but endovascular management is effective, especially for small, deep-seated AVMs, offering a better prognosis.

Trans-radial artery microcatheter angiography-assisted juvenile ruptured brainstem arteriovenous malformation resection.

BACKGROUND: Due to their crucial functional location, surgical treatment of brainstem arteriovenous malformations (AVMs) has always been challenging. For unruptured AVMs, we can determine whether radiological therapy, interventional treatment, or surgical resection is feasible based on the AVM structure. However, for ruptured AVMs, microsurgical resection and interventional embolization are effective methods to prevent further rupture. In the microsurgical resection of AVMs, we usually use a hybrid operation to confirm the AVM structure and determine if the AVM is completely resected during the surgery. METHOD: We report a case of juvenile ruptured brainstem AVM resection. The right lateral position and left suboccipital retrosigmoid approach were used. We established an interventional approach via left radial artery and set a microcatheter in the feeding artery. Methylene blue injection via a microcatheter showed the AVM structure, and we totally resected the brainstem AVM under electrophysiological monitoring and navigation. Intraoperative angiography was performed to ensure complete resection without residual nidus. CONCLUSION: This case demonstrates that the trans-radial approach is convenient and safe for special positions in hybrid operations. Methylene blue injection via a microcatheter in the feeding artery provides clearer visualization of the AVM structure under the microscope.

Use of Polyurethane-Covered Stents for Exclusion of Pulmonary Arteriovenous Malformations.

PURPOSE: To evaluate the safety, technical success and short-term effectiveness of polyurethane-covered stent (PK Papyrus, BioTronik, Berlin) in the treatment of pulmonary arteriovenous malformations (PAVMs) that are not amenable to embolotherapy. MATERIALS AND METHODS: In this IRB-approved, retrospective study, data from patients who received polyurethane-covered stents for exclusion of PAVMs were analyzed. The study included 5 patients (all women) with a median age of 40 years (range 25-60). Patients presented with hypoxemia, TIAs, and/or epistaxis; 4 were confirmed to have HHT. All had multiple PAVMs diagnosed on chest CT and underwent embolization with other devices in addition to the polyurethane-covered stent. The indication for stent placement in all cases was a short and/or tortuous feeding artery. Safety was assessed by immediate or short-term complications, e.g., migration, stent thrombosis, and fracture. Technical success was defined as the ability to accurately place the stent at the intended location. Effectiveness was defined as successful exclusion of PAVM with no perfusion across the AVM. RESULTS: Technical success of stent placement was 100%. AVM exclusion rate was 80% after single stent deployment; in the case of incomplete exclusion, success was achieved using an overlapping stent to completely cover a second feeding artery. During the median follow-up period of 5 months (range 2-10), all stents remained patent, and AVMs were excluded without other complications. CONCLUSION: Exclusion of PAVMs with polyurethane-covered stents is technically feasible, safe, and shows short-term effectiveness for PAVMs with a short/tortuous feeding artery when traditional embolization techniques are not possible.

Increased Collagen I/Collagen III Ratio Is Associated with Hemorrhage in Brain Arteriovenous Malformations in Human and Mouse.

Background: The increase in the collagen I (COL I)/COL III ratio enhances vessel wall stiffness and renders vessels less resistant to blood flow and pressure changes. Activated microglia enhance inflammation-induced fibrosis. Hypotheses: The COL I/COL III ratio in human and mouse brain arteriovenous malformations (bAVMs) is associated with bAVM hemorrhage, and the depletion of microglia decreases the COL I/COL III ratio and hemorrhage. Method: COL I, COL III, and hemorrhages were analyzed in 12 human bAVMs and 6 control brains, and mouse bAVMs induced in three mouse lines with activin receptor-like kinase 1 (n = 7) or endoglin (n = 7) deleted in the endothelial cells or brain focally (n = 5). The controls for the mouse study were no-gene-deleted litter mates. Mouse bAVMs were used to test the relationships between the Col I/Col III ratio and hemorrhage and whether the transient depletion of microglia reduces the Col I/Col III ratio and hemorrhage. Results: The COL I/COL III ratio was higher in the human and mouse bAVMs than in controls. The microhemorrhage in mouse bAVMs was positively correlated with the Col I/Col III ratio. Transient depletion of microglia reduced the Col I/Col III ratio and microhemorrhage. Conclusions: The COL I/COL III ratio in the bAVMs was associated with bAVM hemorrhage. The depletion of microglia reduced the bAVM Col I/Col III ratio and hemorrhage.