Reperfusion of pulmonary arteriovenous malformations after embolotherapy.

Purpose: To describe the mechanisms and risk factors associated with reperfusion of successfully treated pulmonary arteriovenous malformations (PAVMs) after embolotherapy.
Materials and Methods: Among 112 consecutive patients with PAVMs treated by embolotherapy, 19 patients were identified who had 33 angiographically confirmed reperfused PAVMs. A retrospective analysis of computed tomography (CT) and angiography was performed in patients with documented reperfused PAVMs in which reperfused PAVMs were compared with nonreperfused PAVMs. CT images were examined for persistence of the aneurysm and/or draining vein after initial embolotherapy and correlated with angiography to determine the mechanism of reperfusion. PAVM and embolic agent characteristics (eg, feeding artery size and number; PAVM location; coil size, number, and location) were evaluated for association with reperfusion. The outcomes of repeat embolotherapy for reperfused PAVMs were evaluated.
Results: The PAVM aneurysm and/or draining vein persisted on CT after initial embolotherapy in all reperfused PAVMs and resolved in all nonreperfused PAVMs (in patients with nondiffuse PAVMs). Recanalization was the mechanism of reperfusion in 88%. Reperfusion was associated with the use of a single coil (P < .0001), oversized coils (P < .0001), coil placement more than 1 cm from the aneurysm (P < .0001), and increased feeding artery size (P < .001). Repeat embolotherapy for reperfused PAVMs was technically successful in 94% of cases. In the remaining 6% of cases, insufficient feeding artery length prevented safe repeat treatment. After a mean follow-up of 41 months, 42% of reperfused PAVMs in our series have been successfully treated again and occluded.
Conclusions: Recanalization is the most common mechanism of PAVM reperfusion. Increased feeding artery diameter, low number of coils, use of oversized coils, and proximal coil placement within the feeding artery are associated with reperfusion. Distal coil placement facilitates repeat embolization if reperfusion occurs.