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Interventional Radiology Updated April 2026

Pulmonary AVM Embolization

Pulmonary arteriovenous malformations (PAVMs) are right-to-left shunts through an abnormal capillaryless connection between the pulmonary artery and pulmonary vein. Transcatheter embolization of the feeding artery with coils or vascular plugs eliminates the shunt, reverses hypoxemia, and — critically — removes the conduit for paradoxical embolization of venous thrombi and air, which cause stroke and brain abscess in untreated patients.

Key points
  • HHT is the dominant cause: ~80% of PAVMs occur in hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu); ~50% of HHT patients have PAVMs. The remainder are sporadic.
  • Treatment threshold: embolize any PAVM with a feeding artery ≥3 mm diameter, regardless of symptoms — paradoxical stroke and brain abscess risk is present even in asymptomatic patients. Emerging evidence supports treating smaller feeders if technically feasible.
  • Curaçao criteria for HHT: epistaxis, mucocutaneous telangiectasia, visceral AVM (pulmonary/hepatic/cerebral/spinal), and first-degree relative — ≥3 = definite, 2 = possible, ≤1 = unlikely.
  • Classification: simple PAVM — single segmental feeder; complex PAVM — multiple feeders from two or more segmental arteries (higher recurrence).
  • Embolic choice: pushable fibered coils, detachable coils, or Amplatzer vascular plugs deployed as close to the sac as possible without occluding normal branches. Plugs preferred for short feeders (large, single device).
  • Strict air control is mandatory — any air in the catheter system can cross the shunt and cause systemic air embolism (stroke). CO₂ flushing of catheters is contraindicated.
  • Lifelong CT surveillance at 6–12 months post-procedure and every 3–5 years thereafter — reperfusion occurs in 5–15% via recanalization, missed accessory feeders, or pulmonary–pulmonary collaterals.

Indications and Contraindications

IndicationNotes
PAVM with feeding artery ≥3 mmStandard threshold (second international HHT guidelines)
Symptomatic hypoxemia or platypnea-orthodeoxiaRight-to-left shunt producing desaturation
Paradoxical embolization (stroke, TIA, brain abscess)Strong indication; embolize even small PAVMs in this setting
Hemoptysis or hemothorax from PAVM ruptureUrgent embolization
Pregnancy planning in HHTPAVMs can enlarge and rupture during pregnancy; screen and treat pre-conception or in early 2nd trimester
Diffuse PAVM diseasePalliative embolization of largest feeders; adjunct to medical management
TypeContraindication
AbsoluteSevere pulmonary hypertension limiting tolerance of acute afterload change · Uncorrectable coagulopathy
RelativeSevere contrast allergy (premedicate) · Renal impairment (limit contrast) · Very small feeding arteries below microcatheter selectivity

Curaçao Diagnostic Criteria for HHT

CriterionDetail
EpistaxisSpontaneous, recurrent
TelangiectasiasMucocutaneous (lips, oral cavity, fingers, nose)
Visceral AVMPulmonary, hepatic, cerebral, spinal, or GI telangiectasia
Family historyFirst-degree relative with HHT

≥3 criteria = definite HHT; 2 = possible; ≤1 = unlikely.

Classification and Anatomy

TypeArchitectureImplications
Simple PAVMSingle feeding segmental pulmonary artery supplying a single aneurysmal sac; single draining vein~80% of PAVMs; easier to treat; durable occlusion
Complex PAVMTwo or more feeding segmental arteries, often from different subsegmental branches, supplying multiple sacs~20%; higher reperfusion rate; may require multiple sessions
Diffuse PAVMMultiple small PAVMs involving entire lobe(s) or bilateral lungsRare; not fully curable; staged palliative embolization

PAVMs are most common in the lower lobes (60–70%) because of gravity-dependent blood flow. Multiple PAVMs are present in 30–50% of patients.

Screening

  • Contrast echocardiography with agitated saline: first-line screen; delayed left-heart opacification (3–8 cardiac cycles) indicates an intrapulmonary shunt. Graded 1–3.
  • CT chest without contrast (thin-section): definitive anatomic characterization; measure feeding artery diameter; detect accessory feeders.
  • Brain MRI: in all HHT patients to screen for cerebral AVMs before pulmonary intervention.
CT chest showing pulmonary arteriovenous malformation with feeding artery, aneurysmal sac, and draining vein
CT chest demonstrating a pulmonary AVM — feeding segmental pulmonary artery, aneurysmal sac, and draining vein to the left atrium.

Air control is paramount. PAVMs are a direct right-to-left conduit. A micro-bubble introduced through the catheter or sheath can cause systemic arterial air embolism and stroke. Aspirate all lines before injection, eliminate bubbles in contrast syringes, and never use CO₂ as a contrast agent or for catheter flushing.

Procedure Overview

The following is a high-level summary. Full catheter and microcatheter matrix, coil sizing algorithm for PAVM feeders, plug selection by feeder length, and reperfusion salvage strategy are available in RadCall Pro.

Pre-Procedure

  1. Pre-procedure CT: map each PAVM, feeding artery diameter, number of feeders, draining vein, and proximity to normal branches.
  2. Baseline SpO₂ supine and upright; shunt fraction if available.
  3. Anticoagulation: heparin during catheterization per operator preference; avoid inadvertent venous thromboembolism in a patient with right-to-left shunt.

Catheterization

  1. Access: right common femoral vein; 7–8 Fr sheath.
  2. Guide catheter: 6–7 Fr guiding sheath or catheter into the main pulmonary artery; selective segmental pulmonary arteriogram (multiple projections) to confirm feeding artery anatomy and count feeders.
  3. Microcatheter selection: advance coaxial microcatheter (2.4–2.8 Fr) into feeding artery as close to the venous sac as possible, distal to any normal branches.

Embolization

  1. Device selection: Amplatzer vascular plug for short, straight, high-flow feeders (single device = efficient occlusion and low reperfusion); detachable or pushable fibered coils for tortuous feeders or when plug oversizing is not feasible.
  2. Sizing: plug diameter 30–50% greater than feeding artery diameter; anchor coil (first coil) oversized by 20–30% of feeder diameter to prevent migration into the sac or pulmonary vein.
  3. Deployment: occlusive device placed at the most distal feeding artery segment; confirm stasis on angiogram before detachment.
  4. Completion angiogram: confirm cessation of flow into sac and persistent perfusion of normal segmental branches. Address any additional feeders before case end.
Pulmonary angiogram pre-embolization showing filling of the PAVM sac via feeding pulmonary artery
Pre-embolization pulmonary angiogram — contrast filling of the AVM sac via the feeding segmental artery.
Post-embolization pulmonary angiogram showing coils in feeding artery with no residual sac filling
Post-embolization — coils in the feeding artery with stasis and no residual sac filling on completion angiogram.

Device Selection Summary

DeviceBest application
Amplatzer vascular plug (AVP II/IV)Short straight feeders; single device; faster occlusion; lower reperfusion than coils alone
Detachable coilsTortuous or distal feeders; controlled release; precise placement
Pushable fibered coilsInexpensive; larger-volume occlusion; risk of malposition if not oversized
MicroVascular Plug (MVP)Small feeders (3–7 mm); low-profile 2.4 Fr delivery through microcatheter

Complications

ComplicationRateManagement
Pleuritic chest pain / pleurisy10–30%Self-limited; NSAIDs; more common with larger PAVMs and near-pleural sacs
Paradoxical air embolism (angina, stroke, TIA)<1%Preventable with strict air control; 100% oxygen, supportive care if occurs; almost always transient
Device migration to pulmonary vein / systemic circulation<1%Catastrophic if systemic; prevented by proper oversizing; snare retrieval if caught early
Recanalization / reperfusion5–15% (higher for coils than plugs; higher for complex PAVM)Re-embolization at follow-up
Infarction / pulmonary hemorrhageRareUsually self-limited
Contrast reaction / nephropathyLowPremedicate allergic; hydrate

Post-Procedure Care and Surveillance

  • Observation: overnight admission is typical; many centers now discharge same day for uncomplicated single-PAVM cases.
  • Antibiotic prophylaxis: lifelong antibiotic prophylaxis for dental and invasive procedures in HHT with PAVM history — brain abscess risk persists even after embolization due to reperfusion or missed PAVMs.
  • CT surveillance: thin-section chest CT at 6–12 months post-procedure; then every 3 years if stable; lifelong follow-up given reperfusion and new-AVM risk.
  • Criteria for sac resolution: ≥70% reduction in sac diameter or complete disappearance indicates successful occlusion; persistent sac enhancement or enlargement suggests reperfusion.
  • Re-screening: repeat contrast echocardiography in persistent shunt or before pregnancy.
  • Genetic counseling and family screening for HHT patients.

Evidence Summary

  • Faughnan ME et al (2020, Second International HHT Guidelines, Ann Intern Med): embolize all PAVMs with feeding artery ≥3 mm; treat smaller feeders if technically feasible; lifelong CT surveillance.
  • Pollak JS et al (2006, J Vasc Interv Radiol): long-term series showing Amplatzer plug superior to coils for reducing reperfusion.
  • Andersen PE & Kjeldsen AD (2010): long-term follow-up of PAVM embolization; reperfusion 5–15%, mostly amenable to re-embolization.
  • Trerotola SO & Pyeritz RE (2010, AJR): review of PAVM diagnosis and management including the 3-mm feeder threshold — now being revisited downward as smaller feeders carry measurable paradoxical-embolism risk.

References

  1. Faughnan ME, Mager JJ, Hetts SW, et al. Second international guidelines for the diagnosis and management of hereditary hemorrhagic telangiectasia. Ann Intern Med. 2020;173(12):989–1001.
  2. Pollak JS, Saluja S, Thabet A, Henderson KJ, Denbow N, White RI Jr. Clinical and anatomic outcomes after embolotherapy of pulmonary arteriovenous malformations. J Vasc Interv Radiol. 2006;17(1):35–45.
  3. Trerotola SO, Pyeritz RE. PAVM embolization: an update. AJR. 2010;195(4):837–845.
  4. Shovlin CL. Pulmonary arteriovenous malformations. Am J Respir Crit Care Med. 2014;190(11):1217–1228.
  5. Andersen PE, Kjeldsen AD. Clinical and radiological long-term follow-up after embolization of pulmonary arteriovenous malformations. Cardiovasc Intervent Radiol. 2010;33(4):844–851.
  6. Hsu CCT, Kwan GNC, Thompson SA, Evans-Barns H, van Driel ML. Embolisation for pulmonary arteriovenous malformation. Cochrane Database Syst Rev. 2018;1:CD008017.
  7. Shovlin CL, Guttmacher AE, Buscarini E, et al. Diagnostic criteria for hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome). Am J Med Genet. 2000;91(1):66–67.
  8. Related IR guides: pulmonary embolism thrombectomy, pulmonary embolism imaging, IVC filter placement.
Full technique in RadCall Pro Complete catheter and microcatheter matrix, coil sizing algorithm, Amplatzer plug selection by feeder length and diameter, and reperfusion salvage strategies available in RadCall Pro.
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