What is Arteriovenous Malformations (AVMs) & AVFs?
Arteriovenous Malformations (AVMs) are congenital vascular lesions consisting of a nidus of abnormal vessels directly connecting arterial feeders to venous drainage bypassing the normal capillary bed. Arteriovenous Fistulas (AVFs) are abnormal direct arteriovenous connections, often acquired after trauma, surgery, or interventional procedures. Both conditions can cause bleeding, tissue damage, cosmetic deformity, pain, and in large lesions, high-output cardiac failure. Endovascular embolisation and percutaneous sclerotherapy are the cornerstone of modern AVM and AVF treatment minimising surgical risk and providing targeted, effective treatment.
Who is This Procedure For?
Arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) require treatment when they produce symptoms or carry a significant risk of haemorrhage. Indications include symptomatic AVMs presenting with pain, swelling, a pulsatile mass, bruit, progressive skin changes, ulceration, or tissue necrosis (Schobinger Stage II–IV). Treatment is also warranted in lesions with a high risk of bleeding, such as those with prior haemorrhage, rapid growth, or high-risk angiographic features. Cosmetically significant lesions that lead to psychological distress, disfigurement, or noticeable skin discolouration are another important indication. Acquired AVFs, whether post-traumatic, iatrogenic (such as after biopsy or catheter procedures), or post-surgical, may require intervention when they result in haemorrhage, venous hypertension, or ischaemia. Additionally, pre-operative embolisation is often performed to devascularise AVMs before surgical resection, reducing intraoperative blood loss. Treatment is also considered for venous malformations, which are low-flow vascular anomalies that can cause pain, swelling, and functional limitation.
How Are AVMs Treated Endovascularly?
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Diagnostic Angiography & Mapping
Comprehensive angiography characterises the AVM nidus, arterial feeders, venous drainage pattern, and any associated aneurysms essential for treatment planning.
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Multi-disciplinary Planning
Discussion with vascular surgery, plastic surgery, and radiosurgery teams to determine the optimal combination of endovascular, surgical, and/or radiosurgical treatment.
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Superselective Catheterisation
Microcatheter is advanced into individual AVM feeding arteries as close to the nidus as possible minimising off-target embolisation of normal tissue.
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Embolisation / Sclerotherapy
Liquid embolic agents (Onyx, NBCA glue) are injected for arterial components. Direct puncture sclerotherapy (ethanol, bleomycin, STS foam) treats venous components.
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Post-treatment Assessment
Angiography confirms extent of occlusion. Repeat sessions planned at 6–8 week intervals for larger or complex lesions.