Graded Transthoracic Contrast Echocardiography After Pulmonary Arteriovenous Malformation Embolization: Can Chest CT Scan Be Avoided in Patients With a Low-Grade Shunt?

Background: Pulmonary arteriovenous malformations (PAVMs) are direct connections between the pulmonary artery and vein, creating a right-to-left shunt (RLS). Embolization is indicated to prevent complications. Guidelines recommend follow-up chest CT scans to confirm persistent occlusion and embolization of all treatable PAVMs. Graded transthoracic contrast echocardiography (TTCE) after PAVM embolization may offer a reliable alternative in a subgroup of patients while preventing radiation exposure.

Research question: Can TTCE predict the need for additional embolotherapy in the postembolization population as accurately as it does in the treatment-naive population?

Study design and methods: Since 2018, follow-up after PAVM embolization at our study institution includes both TTCE and chest CT scan after 6 to 12 months and every 3 to 5 years thereafter. Patients who underwent at least 1 follow-up TTCE and chest CT scan were included. The indication for additional embolotherapy was discussed in a multidisciplinary team meeting. The primary outcome was the indication for additional embolotherapy in each right-to-left shunt (RLS) grade. Additionally, the association between the RLS grade and indication for additional embolotherapy was investigated.

Results: A total of 339 patients with 412 embolization procedures were included; median time to follow-up TTCE was 7.5 months. An RLS was present in 399 postembolization TTCEs (97%): RLS grade 1 in 93 patients (23%), grade 2 in 149 patients (36%) and grade 3 in 157 patients (38%). In patients with RLS grades 0 and 1, no treatable PAVMs were found on CT scan. In patients with RLS grades 2 and 3, 22 (15%) and 72 (46%) underwent additional embolization.

Interpretation: This study shows chest CT scan might be withheld in patients with RLS grades 0 and 1 after PAVM embolization.