A pulmonary arteriovenous malformation (PAVM) is a rare, congenital vascular malformation. Historically, treatment is embolization with coils or a detachable balloon to prevent the risk of serious complications, such as cerebral embolism/infarct, brain abscess, paradoxical emboli, and high-output right-heart failure. In this patient case, lifestylelimiting symptoms, including dyspnea on exertion and epistaxis, were successfully treated with transcatheter embolization of a large PAVM using a recently developed device called a vascular plug.
CASE
A 51-year-old female was referred to the pulmonology service for evaluation of abnormal findings on chest CT with suspicion of a PAVM in the left lung base. The initial workup by her primary care provider was for abdominal pain in the setting of a family history of colon cancer. The PAVM was an incidental finding on chest CT. During the history, the patient reported shortness of breath with exertion and recurring epistaxis (about three episodes per month). She denied any hemoptysis or pleurisy, and further review of systems was negative. The patient stated that she has a brother who had suffered a stroke and a son who also has frequent epistaxis. Vital signs were normal; and physical examination findings were essentially negative, with no murmurs or evidence of PAVM on auscultation of her lungs.
Imaging studies CT of the chest with 75 mL of iopromide (Ultravist 300) contrast revealed an AV malformation within the left lower lobe (Figure 1). The PAVM measured approximately 2.1 1.5 cm in the anteroposterior dimension. It had only one parent or feeding artery and one draining vein, with venous drainage to the left atrium through an inferior left pulmonary vein. CT of the brain with and without contrast was unremarkable for abscess or any abnormality.
Echocardiography with agitated saline contrast injection (bubble test) demonstrated complete opacification of the left-sided chambers within 13 cycles of bubbles entering the right-sided chambers (Figure 2). This was consistent with a significant AV malformation.
Treatment An interventional radiology consultation was requested to evaluate for possible transcatheter embolization of the parent artery. After a lengthy discussion with the patient and her husband regarding the procedure, potential complications, and alternative treatments, the patient decided to undergo the embolization procedure.
The patient was placed supine on the angiography table, and midazolam injection (Versed) and fentanyl were administered for conscious sedation. Her right groin was prepped, and local anesthesia was administered. The right common femoral vein was accessed using Seldinger technique with ultrasonographic and fluoroscopic guidance. A 10F sheath was positioned in the common femoral vein, and 3,000 U of heparin was administered. A 7F Van Amen catheter was negotiated through the heart and into the left main pulmonary artery with the aid of a tip-deflecting wire. The catheter was then exchanged over an exchange length glidewire (Glidewire; Boston Scientific, Natick, Massachusetts) for an 8F guide catheter (Wiseguide; Boston Scientific). Superselective left lower lobe pulmonary angiography was performed in multiple projections (Figure 3). The guide catheter was advanced into the feeding artery utilizing roadmap technology, which provides a mask image overlay on live fluoroscopy that shows precisely where the guide wire or catheter should be positioned.
The vascular plug (Amplatzer Vascular Plug II; AGA Medical Corporation, Plymouth, Minnesota), which comes preloaded in the insertion device, was carefully prepped in a water bath to expel any air or bubbles from the device. The vascular plug was then deployed into the feeding artery of the PAVM. Proper positioning was verified with contrast enhancement of the feeding artery before final deployment of the device. Repeat superselective left lower lobe pulmonary angiography performed 5 minutes later demonstrated complete occlusion of the PAVM (Figure 4). After confirmation of complete occlusion, the guide catheter was removed. Hemostasis was achieved in the right groin and a pressure dressing was applied. The patient was admitted to the medical floor for 24 hours of close monitoring. Discharge instructions included self monitoring for hemoptysis, increased left lateral chest pain, or new onset of shortness of breath. The patient was instructed to follow up with her pulmonologist in 10 to 14 days. She was also encouraged to return to her normal daily activities 2 to 3 days after the procedure.
