Pulmonary Arteriovenous Malformations

Pulmonary arteriovenous malformations are most commonly seen in patients with hereditary hemorrhagic telangiectasias (Osler-Weber-Rendu syndrome). Pulmonary arteriovenous malformations may be simple (90%) or complex (10%). Simple arteriovenous malformations have a single segmental arterial supply and a single draining vein, while complex arteriovenous malformations have multiple segmental arterial supply and multiple draining veins.

Pulmonary arteriovenous malformations are important in that they provide a right-to-left shunt, which may lead to cerebral infarction or brain abscess. Other common presenting symptoms include hemoptysis, as well as consequences of return of deoxygenated blood to the heart (dyspnea, and fatigue).

Chest radiographs show well-defined nodules that are often lobulated and most commonly seen in the lower lobes and medial third of the lungs. Dynamic contrast-enhance CT can be used for evaluation, but thrombosis may sometimes lead to lack of opacification. CT will show a dilated pulmonary artery feeding directly into a dilated vein that drains into the left atrium. Angiography shows dilated segmental arteries feeding a dilated sac with rapid venous outflow.

Embolotherapy with coils or detachable balloons (for smaller feeding arteries) is the treatment of choice and has a > 90% success rate. Fever and pleuritic chest pain are common post-procedure symptoms.

References

• McCloud. Chapter 2. in Chest Radiology: The Requisites. Mosby 1998.
• Valji K. Chapter 12. in Vascular and interventional radiology. Saunders, 1999.