Graded TTCE for Post-Embolization PAVM Monitoring

Embolization is the standard of care for pulmonary arteriovenous malformations (PAVMs) in the
Hereditary Hemorrhagic Telangiectasia (HHT) population. PAVMs are abnormal connections
between the veins and arteries and result in right-to-left shunting of blood within the
lungs. Successful embolization results in PAVM resolution and decreases the complications
associated with right-to-left shunting. Current guidelines recommend follow-up with interval
chest CT scan to determine treatment success and detect new or recurrent PAVMs after
embolization. This results in significant radiation exposure to the relatively young HHT
population. An alternative to chest CT is graded transthoracic contrast echocardiography
(TTCE), which measures the amount of right-to-left shunting within the lung and assigns a
grade based on this amount. TTCE has the advantage of being radiation free compared to chest
CT. To date, graded TTCE has only been studied as a screening tool for PAVMs. These studies
have shown that graded TTCE is highly sensitive in detecting PAVMs and is comparable to chest
CT when screening for PAVMs. Results indicate that TTCE grade can accurately predict PAVM
size on chest CT and predict whether PAVMs are amenable to embolization. However, no studies
have compared graded TTCE and chest CT in patients who are post-embolization and it is
therefore unknown whether graded TTCE can be used in patients who have undergone PAVM
embolization. The current study seeks to correlate post-embolization TTCE grade with chest CT
findings to determine whether TTCE can accurately predict PAVM size and amenability to
treatment in the post-embolization population.

Inclusion Criteria:

- Age range 18-89 years old

- Diagnosis of Hereditary Hemorrhagic Telangiectasia by the Curacao criteria

- Prior diagnosis of one or more PAVMs treated by embolotherapy

- Chest CT performed within the Penn system for surveillance of PAVMs after \
embolotherapy

Exclusion Criteria:

- Known PAVM recurrence on most recent chest CT with feeding artery size amenable to
repeat embolotherapy

- Known history of intracardiac shunt

- Discovery of intracardiac shunt during transthoracic contrast echocardiography