title: Balloon assessment of patent foramen ovale morphology and the modification of tunnels using a balloon detunnelisation technique.
abstract: OBJECTIVE
  (1) To define patent foramen ovale (PFO) morphology using balloon assessment and identify those with long tunnel type morphology. (2) To describe a novel technique of detunnelisation to facilitate PFO device closure in patients with long tunnel PFO morphology.
  
  
  BACKGROUND
  An appreciation that PFO morphology varies from simple defects through to long tunnel-like defects is important for their successful transcatheter closure. Using standard closure techniques for long tunnels can be problematic.
  
  
  METHODS
  Consecutive patients who underwent transcatheter PFO closure from April 1, 2005 to March 31, 2006 had assessment of PFO morphology using a compliant sizing balloon. The sites of constraint of the balloon allowed identification of the PFO entrance, exit, and length. The PFO was classified as being a long tunnel when the length was greater than the diameter of either the entrance or exit. Those with a long tunnel had detunnelisation performed and the defect was then closed.
  
  
  RESULTS
  44 patients (32 females), mean age 50 years were studied. On balloon assessment 10 (23%) met the criteria for long tunnels. Detunnelisation allowed successful closure with the STARFlex (NMT Medical, Boston, MA) device in 9 of 10 patients. In the other case transseptal puncture was required after detunnelisation before closure.
  
  
  CONCLUSIONS
  Balloon assessment of PFOs enhances the understanding of their morphology and aids the identification of long tunnels. Detunnelisation using the same balloon facilitates the uncomplicated transcatheter closure of long tunnel PFOs in most patients.
authors.affiliation: Adult Congenital Heart Disease Unit, Royal Brompton Hospital, London SW3 6NP, United Kingdom. markspence1@yahoo.co.uk
authors.forename: Mark S
authors.initials: MS
authors.lastname: Spence
authors.forename: Arif A
authors.initials: AA
authors.lastname: Khan
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mullen
mesh_terms: D000328:Adult; D006328:Cardiac Catheterization; D002404:Catheterization / Q000379:methods*; D017548:Echocardiography, Transesophageal; D005260:Female; D005471:Fluoroscopy; D054092:Foramen Ovale, Patent / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D019736:Prostheses and Implants; D019919:Prosthesis Implantation / Q000379:methods*; D025321:Surgery, Computer-Assisted