Correct!
3. Bronchoscopy with fluoroscopically-guided transbronchial biopsy of the right middle lobe lesion
Biopsy, either performed via bronchoscopy with transbronchial biopsy or percutaneous transthoracic needle biopsy, is clearly contraindicated and could potentially precipitate catastrophic hemorrhage. Furthermore, the imaging appearance of the pulmonary lesions alone is diagnostic of arteriovenous malformation and tissue sampling of the lesions by any means is unnecessary. Testing for occult gastrointestinal bleeding is appropriate to screen for potential gastrointestinal vascular lesions. Antibiotic prophylaxis when minor procedures associated with transient bacteremia, such as dental procedures, are performed is important to reduce the risk of paradoxical embolization resulting brain abscess. Assessing for shunt with an echocardiographic bubble study is a reasonable non-invasive means by which to demonstrate the presence of right-to-left shunting. Finally, the definitive treatment for pulmonary arteriovenous malformations of sufficient size or when right-to-left shunting is apparent is catheter pulmonary angiography with embolization.
The patient’s room air oxygen saturation was 94%. Testing for occult gastrointestinal hemorrhage was unrevealing, and no evidence of anemia was noted on a complete blood count. Tiny vascular malformations were noted in the liver on a CT of the abdomen and pelvis, but no large malformations were evident. Echocardiography did not show evidence for pulmonary hypertension (a finding that portends an increased risk of arteriovenous malformation rupture), but the bubble study was positive for right-to-left shunting. The patient subsequently underwent catheter pulmonary angiography with coil embolization of the two largest arteriovenous malformations- the right middle lobe (Figure 5) and right lower lobe- without incident.
Figure 5. A-C: Catheter pulmonary angiography during coil occlusion of an arteriovenous malformation. Injection of the right pulmonary artery shows opacification of the “feeding” artery (arrows) to the large right middle lobe pulmonary arteriovenous malformation nidus (arrowheads); this vessel proximally (approximately at the level of the arrow in B) measured 6.7 mm. Lower: video of catheter pulmonary angiography.
Over the next year, the patient’s migraines improved and serial CT pulmonary angiography assessment of the arteriovenous malformations (Figure 6) showed progressive reduction in both size and degree of enhancement of the embolically treated arteriovenous malformations and their associated feeding arteries in both the right middle and right lower lobes.
Figure 6. Axial enhanced thoracic CT performed using a CT pulmonary angiography protocol at presentation (A), 2 months following coil embolization of the two largest arteriovenous malformations (B), and 10 months following coil embolization of the two largest arteriovenous malformations (C and D) shows that the initially intensely enhancing vascular nidus (arrow in A) displays diminished enhancement 2 months after treatment (arrow in B) and no longer enhances and is markedly decreased in size 10 months following endovascular therapy (arrows in C and D). The large feeding artery is visible prior to therapy (arrowhead in A), shows somewhat diminished enhancement 2 months following endovascular therapy (arrowhead in B), and significantly involutes 10 months following endovascular therapy (arrowheads in C and D). The coils used to treat the smaller right lower lobe arteriovenous malformation are visible in B-D.
Diagnosis: Arteriovenous malformations in the context of hereditary hemorrhagic telangiectasia.
References