title: Triaxial system in re-embolization for recanalization of pulmonary arteriovenous malformations.
abstract: BACKGROUND
  Recanalization occurs occasionally, following coil embolization of pulmonary arteriovenous malformations (PAVM), and can lead to ischemic stroke; therefore re-embolization is important. A 1.9-Fr. no-taper microcatheter that can be inserted into a 2.7-Fr. microcatheter (named the triaxial system) has recently become available, and contributes to super-selective catheterization for small or tortuous vessels. The aim of this study was to evaluate the usefulness of re-embolization for recanalization of PAVM using the triaxial system.
  
  
  METHODS
  Recanalization was diagnosed in 8 patients with 13 PAVMs between June 2011 and November 2012, and re-embolization was attempted with a conventional microcatheter at first in all 13 PAVMs. However, in three of them it failed with the conventional microcatheter, and then the system was exchanged to the triaxial system. Thus, re-embolization using the triaxial system was performed in 3 PAVMs of 3 female patients, with a median age of 63 years (range, 46-73 years). We assessed technical success, complications, and outcome.
  
  
  RESULTS
  The disappearance of recanalization was confirmed by angiography in all re-embolization procedures (technical success rate was 100%). Re-embolization was then successfully achieved inside the original coils, and no branch artery of normal lung tissue was embolized. There were no complications related with this procedure. The blood flow of recanalization was decreased in all cases in a follow-up of 27-33 months (median, 31).
  
  
  CONCLUSIONS
  Triaxial system appears to be useful for recanalization of PAVM, especially in difficult cases with a conventional system.
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Shimohira
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Hashizume
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kawai
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Muto
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Ohta
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Kazushi
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
keywords: Catheterization; Embolization, Therapeutic; Pulmonary Artery