Fact-sheet: Pulmonary arteriovenous malformation
Updated on 07/15/2019 at 10:45 PM
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Definition
Abnormal communication between the pulmonary arterial and venous systems, responsible for a right-to-left shunt.
Isolated or disseminated.
Idiopathic or occurring in the setting of multi-visceral involvement (Rendu-Osler disease or hereditary hemorrhagic telangiectasia).
Congenital or acquired.
Clinical features
Dyspnea secondary to the shunt.
Incidental discovery.
Associated signs of Rendu-Osler disease.
Laboratory findings
Undisturbed.
Radiography
Rounded opacity with well-defined margins.
Ultrasound
Contrast-enhanced ultrasound via transthoracic or transesophageal approach.
Time to appearance of microbubbles (between the left atrium and the PAVM) allows differentiation of a PAVM from an ASD-type shunt.
CT
Reference examination.
Evolutionary spectrum: ground-glass opacity followed by appearance of small vessels/nodule, then visualization of the afferent artery and efferent draining vein.
Subsequent venous dilation.
Complications: Spontaneous thrombosis.
PAVM rupture (perilesional ground-glass opacity).
MRI
Contrast-enhanced MR angiography
would show images identical to CT
but requires greater patient cooperation.
Vascular intervention
X-Ray Angiography, formerly the reference examination.
Therapeutic management.
Nuclear medicine
Technetium-99m pulmonary perfusion scintigraphy (shunt quantification and follow-up of residual shunt).
Management
Therapeutic management:
- Embolization (shunt reduction / stroke prevention / prior to pregnancy).
- Surgery if size is too large.
Classification
Classification:
Type 1: simple PAVM (single afferent artery).
Type 2: complex PAVM (multiple afferent arteries arising from a single segmental artery).
Type 3: complex PAVM (multiple afferent arteries arising from multiple segmental arteries).
Differential diagnosis
Any nodular image.
Value of a contrast-enhanced CT prior to any biopsy.