Algorithm for treating pulmonary arteriovenous malformations

CT: computed tomography; PAVM: pulmonary arteriovenous malformation; TTCE: transthoracic contrast echocardiography; PH: pulmonary hypertension.

* A cutoff for feeding artery size ≥3 mm is a universally agreed upon diameter as most interventional radiologists can readily access pulmonary arteries of this size. However, it is generally accepted that PAVMS ≥2 mm should also be targeted angiographically, when feasible.

¶ In our experience patients can tolerate contrast safely with appropriate pre-medication (please refer to the UpToDate topic for the treatment of patients with contrast allergies).

Δ Some PAVMS may be previously identified on CT while others may not have been identified on CT.

◊ Surgery may be an option for PAVMS not amenable to embolotherapy or for patients with life-threatening hemorrhage in a facility without access to embolotherapy.

§ Some patients with a persistent PAVM or grade 2 to 3 shunt on TTCE may be followed with 3 to 5 year chest CT scans. However, those with successful closure by CT and a grade 0 to 1 shunt on TTCE can be followed with TTCE to limit radiation exposure from CT.

¥ Reasons for lack of response to embolotherapy include failed embolotherapy (eg, coil migration), the development of new symptomatic PAVMS and/or the development of PH. This population may present with worsening symptoms or persistent or new PAVMS on CT. For those in whom PH is suspected, right heart catheterization may be appropriate. Please refer to the UpToDate topic on the therapeutic approach to adult patients with PAVMS.

‡ Surgery is rarely needed since embolization is typically successful. Surgery may also be indicated in patients with life-threatening acute hemorrhage from a ruptured PAVM in a facility without access to embolotherapy.

† Lung transplantation is a last resort therapy especially for those with diffuse bilateral disease and/or those who are at considerable risk of dying from their underlying PAVM. Please refer to the UpToDate topic on the therapeutic approach to adult patients with PAVMS.