Pulmonary AVM Embolization

Background and indications

Venous malformations (VM) are the most common vascular malformations. They are congenital low-flow anomalies consisting of ectatic veins with thinned walls. They present as a compressible, bluish mass that increases in size with dependency or exertion. They can cause pain, cosmetic concerns, localized coagulopathy (elevated D-dimers), and compression of adjacent structures.

Percutaneous sclerotherapy is the first-line treatment for symptomatic VMs, aiming to destroy the abnormal endothelium and induce obliterative fibrosis of venous cavities.

Pre-procedure assessment

Assessment includes MRI with T2 and gadolinium sequences (extension, anatomic relationships, characteristic progressive filling), Doppler ultrasound, D-dimer and fibrinogen levels (localized consumptive coagulopathy common in extensive VMs). Classification is confirmed (ISSVA 2018).

Procedure

Under general anesthesia (or local/sedation for small VMs), one or more needles are inserted into the malformation under ultrasound guidance. Intra-procedural phlebography visualizes architecture and venous drainage. The sclerosing agent is injected: 95% ethanol (most effective, reserved for deep VMs), 1-3% polidocanol foam (Aethoxysklerol), bleomycin, or doxycycline. Volume is limited by patient weight (ethanol: max 1 mL/kg). Multiple sessions 6-8 weeks apart are usually needed (3-5 sessions on average).

Results and scientific evidence

Sclerotherapy offers clinical improvement (pain, volume) in 80-95% of cases after multiple sessions. Ethanol is the most effective agent but with more side effects than foam-based agents. D-dimer normalization is a good marker of treatment response.

Risks and complications

Post-procedure swelling and pain (near-universal, resolving in 1-2 weeks), skin blistering (5-10% with ethanol), skin necrosis (2-5% if superficial VM, mainly with ethanol), nerve injury (1-3%, mainly for extremity VMs), deep vein thrombosis (< 2%), transient hemoglobinuria (with ethanol, if high volumes).

Recovery

1 night hospitalization (or outpatient for small VMs). Elastic compression of treated area for 2-4 weeks. Control MRI at 3 months to evaluate response and plan subsequent sessions.

Practical information

The procedure is performed as an outpatient or short inpatient stay depending on the case. It is performed by an interventional radiologist specialized in vascular malformations.