First-in-human case series of Embrace, a polyethylene glycol-based liquid embolic agent, utilisation for embolisation of arterial haemorrhage

First-in-human case series of Embrace, a polyethylene glycol-based liquid embolic agent, utilisation for embolisation of arterial haemorrhage | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article First-in-human case series of Embrace, a polyethylene glycol-based liquid embolic agent, utilisation for embolisation of arterial haemorrhage Gerard S Goh, Tuan Phan, Charles Handley, Adil Zia, Dominic Buensalido, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7236105/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 5 You are reading this latest preprint version Abstract Background : There are a number of liquid embolic agents available and in development for the use of endovascular embolization. The Embrace Hydrogel Embolic System (HES) is an aqueous polyethylene glycol (PEG)-based liquid embolic agent that has been used for the treatment of hypervascular tumours. This case series describes the first in human use of Embrace for the treatment of arterial haemorrhage. Case Presentation : 2 patients were enrolled into this study. The first patient was a 64 year old male and had active arterial pelvic haemorrhage after a motor vehicle accident and Embrace was used to stop the pelvic haemorrhage. The second patient was a 73 year old male had active bleeding from the right L4 lumbar artery whilst on therapeutic enoxaparin for a deep vein thrombosis that developed following excision of a L2/3 facet joint cyst 10 days prior. The technical success was 100% in stopping bleeding at the tie of procedure with no rebleeding to 30 days. Conclusions : In this small case series Embrace was successful in being able to stop active arterial bleeding. Further assessment of Embrace is underway in a larger multi-centre clinical trial. Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Arterial embolisation is effective in managing haemorrhage. Due to the customisable physical properties of liquid embolic agents, such as viscosity, compressibility, solidification time, bioabsorbability and radio-opacity, there are almost limitless combinations of properties, enabling a tailored approach for embolisation. Several polymers have been designed successfully for the development of liquid embolic agents 1 . The Embrace Hydrogel Embolic System (HES) (Instylla, Bedford, Massachusetts) is an aqueous polyethylene glycol based liquid embolic agent. It consists of two low viscosity precursors, a polymer and an initiator, that are introduced into the target vessel using a co-axial microcatheter system. The polymer and initiator polymerize intravascularly, forming a soft hydrogel cast within the distal vasculature. This innovative agent has been used for the embolisation of hypervascular tumours, demonstrating promising results. 2 The study aimed to assess the safety, effectiveness and preliminary benefit-risk profile of Embrace HES to embolise vascular territories for the treatment of arterial bleeding, reporting the first in human use of Embrace to stop active arterial bleeding. Methods A prospective, phase 1 observational pilot study was conducted with local ethics approval and registered with the Australian New Zealand Clinical Trials Registry (ACTRN12620000349943). Inclusion criteria included patients > 18 years with angiographic active bleeding suitable for embolisation. The primary end point was technical success, defined as cessation of angiographic extravasation, complete vascular exclusion of damaged area, and/or occlusion of the targeted vessel on post-embolisation angiography. Secondary endpoints included the absence of re-bleeding at 72 hours and 30 days post-embolisation, and the avoidance of further interventions. Safety endpoints included assessment of all adverse events. Exclusion criteria included pregnancy or breast-feeding, contraindications to angiography (e.g. contrast allergy), > 38 hours from the initial injury, haemorrhagic shock or exsanguinating haemorrhage, grade 6 injury of any organ on the American Association for the Surgery of Trauma Organ Injury scale, untreated pneumothorax or haemothorax, penetrating cardiac or thoracic aortic trauma, and patients who had received > 5 consecutive minutes of cardiopulmonary resuscitation in the pre-emergency department setting. Patients with active haemorrhage on computed tomography angiography (CTA) underwent angiography. 5Fr sheath vascular access in the right common femoral artery and a Cobra C2 catheter was advanced into the feeding artery. The Embrace HES co-axial microcatheter system was positioned proximal to the bleeding site, and the agent was delivered consistent with techniques described in a previously published first-in-human pilot study of Embrace for embolisation of malignant and benign hypervascular tumours 1 . Case Report Patient 1: 64-year-old male involved in a high-speed motor vehicle accident, resulting in multiple pelvic and left-sided rib fractures. CTA demonstrated active haemorrhage from the right internal pudendal artery (Fig. 1 ). The patient’s vital signs were blood pressure 147/86 mmHg and heart rate 105 bpm. The patient was not on any anticoagulants or antiplatelet agents and had received one unit of packed red blood cells (PRBC). A Cobra C2 catheter was advanced into the ipsilateral internal iliac artery. Angiography confirmed active haemorrhage (Fig. 2 ). The Embrace HES co-axial microcatheter system was placed in the internal pudendal artery and a total volume of 1.6 mL of Embrace was delivered. Post-embolisation angiography demonstrated complete cessation of haemorrhage (Fig. 2 ). The patient experienced no further bleeding events over the 30-day follow-up period. Patient 2: 73-year-old male referred on postoperative day 10 following excision of a L2/3 facet joint cyst causing local mass effect and myelopathy. Past Medical history included hypertension, multiple myeloma, glaucoma, meningioma and a lumbar laminectomy for spinal stenosis. He had developed deep vein thrombosis and was being treated with subcutaneous enoxaparin (90 mg twice daily), with the last dose given approximately 24hours before embolisation. CTA demonstrated multiple areas of active haemorrhage within a right psoas muscle haematoma (Fig. 3 ). The patient’s vital signs were blood pressure 100/49 mmHg and heart rate 120 bpm. A Cobra C2 catheter was used to interrogate the right lumbar arteries. Angiography confirmed haemorrhage originating from the right L4 lumbar artery (Fig. 4 ). The Embrace HES co-axial microcatheter system was used to deliver a total volume of 1.8 mL of Embrace, achieving complete embolisation as confirmed by post-procedure angiography (Fig. 4 ). The patient developed a ventricular fibrillation arrest post-procedure, which was managed with cardiopulmonary resuscitation and defibrillation. He made an uneventful recovery. Upon investigation by both the treating Interventional Radiologist and an independent medical monitor, this serious adverse event was determined as unlikely related to the study device/study procedure, but due to the pre-existing medical conditions of the patient. No further bleeding was observed during the 30-day follow-up period. An Investigational device exemption (IDE) study was subsequently approved and enrolment to this study was ceased. The IDE study, “HALT: Embrace Hydrogel Embolic System (HES) for Embolisation of Peripheral Arterial Bleeds” is currently enrolling patients (clinicaltrials.gov ID: NCT05364502) and aims to recruit 118 patients in up to 25 sites in the United States. Discussion This case series demonstrates the successful use of Embrace HES in managing arterial haemorrhage. This is the first report of its application in controlling arterial haemorrhage in humans. Embolisation is a lifesaving procedure that can control bleeding in an expeditious and minimally invasive manner with less disruption of normal tissues than standard surgical intervention 3 . Many embolic agents, such as coils, plugs and particles, do not achieve complete cross-sectional occlusion and these agents rely facilitating physiological haemostasis, which can be problematic in patients with coagulopathies or anticoagulation therapy. Many liquid embolics, such as Embrace, can achieve complete cross-sectional occlusion of arteries independent of the patient’s coagulation status. This capability enables earlier treatment without the need to reverse anticoagulation, potentially reducing morbidity and mortality associated with delayed interventions. The findings from this small case series emphasises the potential of Embrace as a valuable tool in the endovascular management of arterial bleeding, with results from larger, ongoing studies like the HALT trial expected to provide further insights into its safety and efficacy. Conclusion In this first-in-human case series, the Embrace Hydrogel Embolic System demonstrated promising outcomes in managing arterial haemorrhage. There was 100% technical success, with no recurrence of bleeding at 30 days. These preliminary findings support its use in endovascular treatment and warrant further investigation in larger clinical trials, such as the ongoing HALT study, to confirm its safety and efficacy. Declarations Ethical Approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Local institutional review board approval from Alfred Health was granted. Consent for publication: Consent for publication was obtained for every individual person’s data included in the study. Availability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Competing Interests: All authors have received research funding from Instylla Inc. Funding: This study was funded by Instylla Inc. Author’s contributions: GG and TP performed the procedures, GG TP CH AZ DB and HK were involved in the study implementation, data collection, data analysis and were major contributors in writing the manuscript. All authors read and approved the final manuscript Acknowledgements: Not applicable References Pal A, Blanzy J, Gómez KJR, Preul MC, Vernon BL. Liquid Embolic Agents for Endovascular Embolization: A Review. Gels. 2023 May 4;9(5):378 Goh GS, Goodwin MD, Huang JF, Kavnoudias H, Holden A. A Pilot First-in-Human Study of Embrace, a Polyethylene Glycol-Based Liquid Embolic Agent, in the Embolization of Malignant and Benign Hypervascular Tumors. J Vasc Interv Radiol. 2022 Jun;33(6):660-667. Lopera JE. Embolization in trauma: principles and techniques. Semin Intervent Radiol. 2010 Mar;27(1):14-28. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Major revision 30 Sep, 2025 Reviewers agreed at journal 15 Aug, 2025 Reviewers invited by journal 15 Aug, 2025 Editor assigned by journal 05 Aug, 2025 First submitted to journal 03 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7236105","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":500880604,"identity":"ba5b6ef5-70c2-4a1f-b1c8-b346993855e6","order_by":0,"name":"Gerard S Goh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2klEQVRIie3OIQvCQBjG8VcOvPLo6mCiX0EZiGnzo5wcmAyKZaDgpe0zCOJnMJmVgZYVm0kUwWQwmXVYtNxcE7x/fLkfzxGZTD8ao4AqXBHZOUhCwCoXKYR5SK3Nd+fB3AOceL2n4OApntS1pLHC0J0uJVDuyhYlQ6nQyyAKXae0ZPCBpl0IhST6iswmAKz7i1hXPakR3zglFT8JiinxyM5YqTMwF5ttKtyWSIQo2pe+fiWKTmeMR1WAnfa3QPiWJRf6lRhv3xBEnVD7Pl1R/Phx8LOEyWQy/V8PP5g3VFiu9mEAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-1552-5470","institution":"Alfred Hospital","correspondingAuthor":true,"prefix":"","firstName":"Gerard","middleName":"S","lastName":"Goh","suffix":""},{"id":500880605,"identity":"1b95728e-c1a3-4a18-ab38-3d1eec859753","order_by":1,"name":"Tuan Phan","email":"","orcid":"","institution":"Alfred Health","correspondingAuthor":false,"prefix":"","firstName":"Tuan","middleName":"","lastName":"Phan","suffix":""},{"id":500880606,"identity":"62f79b8d-8367-4aff-9b01-c411a3f126ce","order_by":2,"name":"Charles Handley","email":"","orcid":"","institution":"Monash Medical Centre","correspondingAuthor":false,"prefix":"","firstName":"Charles","middleName":"","lastName":"Handley","suffix":""},{"id":500880607,"identity":"11e59160-17bf-4300-9846-206058d0128c","order_by":3,"name":"Adil Zia","email":"","orcid":"","institution":"Alfred Health","correspondingAuthor":false,"prefix":"","firstName":"Adil","middleName":"","lastName":"Zia","suffix":""},{"id":500880608,"identity":"2bdaab09-0f66-4d56-a268-c2ef9a99e5a4","order_by":4,"name":"Dominic Buensalido","email":"","orcid":"","institution":"Alfred Health","correspondingAuthor":false,"prefix":"","firstName":"Dominic","middleName":"","lastName":"Buensalido","suffix":""},{"id":500880609,"identity":"02e8c211-32e8-4845-be89-eba6f5063f35","order_by":5,"name":"Helen Kavnoudias","email":"","orcid":"","institution":"Alfred Health","correspondingAuthor":false,"prefix":"","firstName":"Helen","middleName":"","lastName":"Kavnoudias","suffix":""}],"badges":[],"createdAt":"2025-07-28 16:55:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7236105/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7236105/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":89673139,"identity":"e220a471-6969-45be-8323-3d57b40e804b","added_by":"auto","created_at":"2025-08-22 13:12:32","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":63570,"visible":true,"origin":"","legend":"\u003cp\u003ePatient 1 Axial CTA demonstrating active haemorrhage from the right internal pudendal artery\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7236105/v1/6bf2af5821d74a867384a6a7.jpeg"},{"id":89673698,"identity":"2e94f587-c688-4217-bcf0-654521d2be8e","added_by":"auto","created_at":"2025-08-22 13:20:32","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":562407,"visible":true,"origin":"","legend":"\u003cp\u003ePatient 1 Left: Angiography of the right pudendal artery demonstrating active haemorrhage (arrow). Right: Angiography post embolisation with Embrace demonstrating cessation of haemorrhage\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7236105/v1/1477ba220d9c9d2131e0f381.jpeg"},{"id":89673142,"identity":"13a2f349-a319-4a5a-8c2f-f4e03e02994d","added_by":"auto","created_at":"2025-08-22 13:12:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":214348,"visible":true,"origin":"","legend":"\u003cp\u003ePatient 2 Coronal CTA demonstrating active haemorrhage within a right psoas muscle haematoma.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7236105/v1/618f22e0d22d805518f2d13d.png"},{"id":89673151,"identity":"3db094c5-0e6c-4b1f-85df-4142ba2663a4","added_by":"auto","created_at":"2025-08-22 13:12:32","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":345811,"visible":true,"origin":"","legend":"\u003cp\u003ePatient 2 Left: Angiography of the active haemorrhage (arrow). Right: Angiography post embolisation with Embrace demonstrating cessation of haemorrhage\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7236105/v1/89b4b8649481c002a13cbb14.jpeg"},{"id":89674878,"identity":"76cd6b1a-ff14-4069-88f6-4a93838d563d","added_by":"auto","created_at":"2025-08-22 13:28:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1463250,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7236105/v1/7052bda0-3467-42a0-ae40-31386f2992e1.pdf"}],"financialInterests":"","formattedTitle":"First-in-human case series of Embrace, a polyethylene glycol-based liquid embolic agent, utilisation for embolisation of arterial haemorrhage","fulltext":[{"header":"Introduction","content":"\u003cp\u003eArterial embolisation is effective in managing haemorrhage. Due to the customisable physical properties of liquid embolic agents, such as viscosity, compressibility, solidification time, bioabsorbability and radio-opacity, there are almost limitless combinations of properties, enabling a tailored approach for embolisation. Several polymers have been designed successfully for the development of liquid embolic agents\u003csup\u003e1\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe Embrace Hydrogel Embolic System (HES) (Instylla, Bedford, Massachusetts) is an aqueous polyethylene glycol based liquid embolic agent. It consists of two low viscosity precursors, a polymer and an initiator, that are introduced into the target vessel using a co-axial microcatheter system. The polymer and initiator polymerize intravascularly, forming a soft hydrogel cast within the distal vasculature. This innovative agent has been used for the embolisation of hypervascular tumours, demonstrating promising results.\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eThe study aimed to assess the safety, effectiveness and preliminary benefit-risk profile of Embrace HES to embolise vascular territories for the treatment of arterial bleeding, reporting the first in human use of Embrace to stop active arterial bleeding.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eA prospective, phase 1 observational pilot study was conducted with local ethics approval and registered with the Australian New Zealand Clinical Trials Registry (ACTRN12620000349943).\u003c/p\u003e\u003cp\u003eInclusion criteria included patients\u0026thinsp;\u0026gt;\u0026thinsp;18 years with angiographic active bleeding suitable for embolisation. The primary end point was technical success, defined as cessation of angiographic extravasation, complete vascular exclusion of damaged area, and/or occlusion of the targeted vessel on post-embolisation angiography. Secondary endpoints included the absence of re-bleeding at 72 hours and 30 days post-embolisation, and the avoidance of further interventions. Safety endpoints included assessment of all adverse events.\u003c/p\u003e\u003cp\u003eExclusion criteria included pregnancy or breast-feeding, contraindications to angiography (e.g. contrast allergy), \u0026gt;\u0026thinsp;38 hours from the initial injury, haemorrhagic shock or exsanguinating haemorrhage, grade 6 injury of any organ on the American Association for the Surgery of Trauma Organ Injury scale, untreated pneumothorax or haemothorax, penetrating cardiac or thoracic aortic trauma, and patients who had received\u0026thinsp;\u0026gt;\u0026thinsp;5 consecutive minutes of cardiopulmonary resuscitation in the pre-emergency department setting.\u003c/p\u003e\u003cp\u003ePatients with active haemorrhage on computed tomography angiography (CTA) underwent angiography. 5Fr sheath vascular access in the right common femoral artery and a Cobra C2 catheter was advanced into the feeding artery. The Embrace HES co-axial microcatheter system was positioned proximal to the bleeding site, and the agent was delivered consistent with techniques described in a previously published first-in-human pilot study of Embrace for embolisation of malignant and benign hypervascular tumours\u003csup\u003e1\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Case Report","content":"\u003cp\u003ePatient 1: 64-year-old male involved in a high-speed motor vehicle accident, resulting in multiple pelvic and left-sided rib fractures. CTA demonstrated active haemorrhage from the right internal pudendal artery (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The patient\u0026rsquo;s vital signs were blood pressure 147/86 mmHg and heart rate 105 bpm. The patient was not on any anticoagulants or antiplatelet agents and had received one unit of packed red blood cells (PRBC).\u003c/p\u003e\u003cp\u003eA Cobra C2 catheter was advanced into the ipsilateral internal iliac artery. Angiography confirmed active haemorrhage (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The Embrace HES co-axial microcatheter system was placed in the internal pudendal artery and a total volume of 1.6 mL of Embrace was delivered. Post-embolisation angiography demonstrated complete cessation of haemorrhage (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The patient experienced no further bleeding events over the 30-day follow-up period.\u003c/p\u003e\u003cp\u003ePatient 2: 73-year-old male referred on postoperative day 10 following excision of a L2/3 facet joint cyst causing local mass effect and myelopathy. Past Medical history included hypertension, multiple myeloma, glaucoma, meningioma and a lumbar laminectomy for spinal stenosis. He had developed deep vein thrombosis and was being treated with subcutaneous enoxaparin (90 mg twice daily), with the last dose given approximately 24hours before embolisation.\u003c/p\u003e\u003cp\u003eCTA demonstrated multiple areas of active haemorrhage within a right psoas muscle haematoma (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The patient\u0026rsquo;s vital signs were blood pressure 100/49 mmHg and heart rate 120 bpm. A Cobra C2 catheter was used to interrogate the right lumbar arteries. Angiography confirmed haemorrhage originating from the right L4 lumbar artery (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The Embrace HES co-axial microcatheter system was used to deliver a total volume of 1.8 mL of Embrace, achieving complete embolisation as confirmed by post-procedure angiography (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe patient developed a ventricular fibrillation arrest post-procedure, which was managed with cardiopulmonary resuscitation and defibrillation. He made an uneventful recovery. Upon investigation by both the treating Interventional Radiologist and an independent medical monitor, this serious adverse event was determined as unlikely related to the study device/study procedure, but due to the pre-existing medical conditions of the patient. No further bleeding was observed during the 30-day follow-up period.\u003c/p\u003e\u003cp\u003eAn Investigational device exemption (IDE) study was subsequently approved and enrolment to this study was ceased. The IDE study, \u0026ldquo;HALT: Embrace Hydrogel Embolic System (HES) for Embolisation of Peripheral Arterial Bleeds\u0026rdquo; is currently enrolling patients (clinicaltrials.gov ID: NCT05364502) and aims to recruit 118 patients in up to 25 sites in the United States.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis case series demonstrates the successful use of Embrace HES in managing arterial haemorrhage. This is the first report of its application in controlling arterial haemorrhage in humans.\u003c/p\u003e\u003cp\u003eEmbolisation is a lifesaving procedure that can control bleeding in an expeditious and minimally invasive manner with less disruption of normal tissues than standard surgical intervention\u003csup\u003e3\u003c/sup\u003e. Many embolic agents, such as coils, plugs and particles, do not achieve complete cross-sectional occlusion and these agents rely facilitating physiological haemostasis, which can be problematic in patients with coagulopathies or anticoagulation therapy.\u003c/p\u003e\u003cp\u003eMany liquid embolics, such as Embrace, can achieve complete cross-sectional occlusion of arteries independent of the patient\u0026rsquo;s coagulation status. This capability enables earlier treatment without the need to reverse anticoagulation, potentially reducing morbidity and mortality associated with delayed interventions. The findings from this small case series emphasises the potential of Embrace as a valuable tool in the endovascular management of arterial bleeding, with results from larger, ongoing studies like the HALT trial expected to provide further insights into its safety and efficacy.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this first-in-human case series, the Embrace Hydrogel Embolic System demonstrated promising outcomes in managing arterial haemorrhage. There was 100% technical success, with no recurrence of bleeding at 30 days. These preliminary findings support its use in endovascular treatment and warrant further investigation in larger clinical trials, such as the ongoing HALT study, to confirm its safety and efficacy.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthical Approval:\u0026nbsp;All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Local institutional review board approval from Alfred Health was granted.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConsent for publication: Consent for publication was obtained for every individual person\u0026rsquo;s data included in the study.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials:\u0026nbsp;The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003eCompeting Interests: All authors have received research funding from Instylla Inc.\u003c/p\u003e\n\u003cp\u003eFunding: This study was funded by Instylla Inc.\u003c/p\u003e\n\u003cp\u003eAuthor\u0026rsquo;s contributions: GG and TP performed the procedures, GG TP CH AZ DB and HK were involved in the study implementation, data collection, data analysis and were major contributors in writing the manuscript.\u0026nbsp;All authors read and approved the final manuscript\u003c/p\u003e\n\u003cp\u003eAcknowledgements: Not applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003ePal A, Blanzy J, G\u0026oacute;mez KJR, Preul MC, Vernon BL. Liquid Embolic Agents for Endovascular Embolization: A Review. Gels. 2023 May 4;9(5):378\u003c/li\u003e\n \u003cli\u003eGoh GS, Goodwin MD, Huang JF, Kavnoudias H, Holden A. A Pilot First-in-Human Study of Embrace, a Polyethylene Glycol-Based Liquid Embolic Agent, in the Embolization of Malignant and Benign Hypervascular Tumors. J Vasc Interv Radiol. 2022 Jun;33(6):660-667.\u003c/li\u003e\n \u003cli\u003eLopera JE. Embolization in trauma: principles and techniques. Semin Intervent Radiol. 2010 Mar;27(1):14-28.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"cvir-endovascular","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cire","sideBox":"Learn more about [CVIR Endovascular](https://www.springer.com/journal/42155)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/cire/default.aspx","title":"CVIR Endovascular","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7236105/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7236105/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eThere are a number of liquid embolic agents available and in development for the use of endovascular embolization. The Embrace Hydrogel Embolic System (HES) is an aqueous polyethylene glycol (PEG)-based liquid embolic agent that has been used for the treatment of hypervascular tumours. This case series describes the first in human use of Embrace for the treatment of arterial haemorrhage.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase Presentation\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003e2 patients were enrolled into this study. The first patient was a 64 year old male and had active arterial pelvic haemorrhage after a motor vehicle accident and Embrace was used to stop the pelvic haemorrhage. The second patient was a 73 year old male had active bleeding from the right L4 lumbar artery whilst on therapeutic enoxaparin for a deep vein thrombosis that developed following excision of a L2/3 facet joint cyst 10 days prior. The technical success was 100% in stopping bleeding at the tie of procedure with no rebleeding to 30 days.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eIn this small case series Embrace was successful in being able to stop active arterial bleeding. Further assessment of Embrace is underway in a larger multi-centre clinical trial.\u003c/p\u003e","manuscriptTitle":"First-in-human case series of Embrace, a polyethylene glycol-based liquid embolic agent, utilisation for embolisation of arterial haemorrhage","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-22 13:12:27","doi":"10.21203/rs.3.rs-7236105/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2025-09-30T05:44:25+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-08-15T15:17:25+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-15T07:37:32+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-05T05:53:33+00:00","index":"","fulltext":""},{"type":"submitted","content":"CVIR Endovascular","date":"2025-08-04T00:29:33+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"cvir-endovascular","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cire","sideBox":"Learn more about [CVIR Endovascular](https://www.springer.com/journal/42155)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/cire/default.aspx","title":"CVIR Endovascular","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"25e638d5-59dc-4af7-b444-08af0afac57a","owner":[],"postedDate":"August 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2025-12-11T02:50:25+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-22 13:12:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7236105","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7236105","identity":"rs-7236105","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}