title: Reperfusion of pulmonary arteriovenous malformations after embolotherapy.
abstract: OBJECTIVE
  To describe the mechanisms and risk factors associated with reperfusion of successfully treated pulmonary arteriovenous malformations (PAVMs) after embolotherapy.
  
  
  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.
authors.affiliation: Department of Medical Imaging, Faculty of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Milic
authors.forename: Raymond P
authors.initials: RP
authors.lastname: Chan
authors.forename: Justine H
authors.initials: JH
authors.lastname: Cohen
authors.forename: Marie E
authors.initials: ME
authors.lastname: Faughnan
mesh_terms: D000328:Adult; D000783:Aneurysm / Q000000981:diagnostic imaging / Q000628:therapy; D001165:Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000628:therapy*; D004621:Embolization, Therapeutic / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011651:Pulmonary Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging; D015641:Radiography, Interventional; D015424:Reperfusion / Q000295:instrumentation / Q000379:methods*; D019233:Retreatment; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency