title: Determinants and clinical significance of persistent residual shunting in patients with percutaneous patent foramen ovale closure devices.
abstract: BACKGROUND
  Percutaneous patent foramen closure has emerged as a dynamic therapy for stroke prevention secondary to paradoxical embolism. Recent reports, however, have documented uncertain clinical efficacy and patients with incomplete PFO closure may remain at risk of recurrent events. We sought to identify echocardiographic determinants and the clinical significance of persistent residual shunting after percutaneous PFO closure.
  
  
  METHODS
  From 2002 to 2008, 51 consecutive patients with recurrent stroke (n=46) or transient ischemic attack (TIA) (n=5) underwent percutaneous PFO closure at a tertiary care hospital. PFO size, degree of shunt, tunnel length, and atrial septal aneurysm geometry were documented at the time of device implantation. All patients received follow-up with transesophageal (n=43) or transthoracic (n=8) echocardiography 6.7+/-2 months post procedure and presence of residual shunting and recurrent stroke/TIA were recorded.
  
  
  RESULTS
  All patients underwent percutaneous PFO closure without complication. Ten patients (20%) demonstrated residual right-to-left shunting at the time of follow-up: color Doppler (2), mild (n=3), moderate (n=2) and severe (n=3). Univariate analysis revealed larger PFO size (F=4.71, p=0.036) as the only independent predictor of residual shunting after PFO closure. Ninety six percent of patients remained stroke and TIA free 3 years+/-8 months post closure, with no clinical differences between the two groups.
  
  
  CONCLUSIONS
  In patients undergoing percutaneous PFO closure for stroke or TIA, a larger PFO size predisposes to residual shunting approximately 6 months post PFO closure, but with no short term increased risk of recurrent thromboembolic events.
authors.forename: Nabil A
authors.initials: NA
authors.lastname: Shafi
authors.forename: Raymond G
authors.initials: RG
authors.lastname: McKay
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Kiernan
authors.forename: Isaac E
authors.initials: IE
authors.lastname: Silverman
authors.forename: Martha
authors.initials: M
authors.lastname: Ahlquist
authors.forename: David I
authors.initials: DI
authors.lastname: Silverman
mesh_terms: D016009:Chi-Square Distribution; D004452:Echocardiography; D019320:Embolism, Paradoxical / Q000209:etiology* / Q000517:prevention & control*; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D016896:Treatment Outcome