title: Prevalence of "silent" pulmonary emboli in adults after the Fontan operation.
abstract: OBJECTIVE
  The study was done to determine the prevalence of pulmonary emboli (PE) in asymptomatic adult Fontan patients and to identify the risk factors associated with PE.
  
  
  BACKGROUND
  Right atrial thrombi and systemic thromboembolic complications have been reported after the Fontan procedure. However, the frequency of silent PE in this patient population is not known.
  
  
  METHODS
  All consecutive adult Fontan patients attending the adult congenital clinic over a six-month period underwent ventilation-perfusion (VQ) scanning and blood testing for thrombophilia tendency. If the VQ scan showed an intermediate or high probability for PE, a computerized tomography (CT) pulmonary angiogram was performed to confirm the presence of PE.
  
  
  RESULTS
  Thirty patients (mean age 26 +/- 7 years, 57% men) were included in this study. Five (17%) adult Fontan patients had an intermediate or high probability for PE on VQ scan, all of which were confirmed on CT pulmonary angiography. No patient had a thrombophilia tendency. Pulmonary emboli were not present in any patients (30%) taking warfarin. Late age at time of Fontan operation (19 +/- 6 years vs. 11 +/- 6 years, p = 0.012) and type of Fontan anatomy (p = 0.001) were associated with increased risk of silent PE.
  
  
  CONCLUSIONS
  Seventeen percent of adult patients with Fontan procedure have clinically silent PE. The long-term hemodynamic implications of this with respect to Fontan attrition over time are unknown. Large randomized prospective studies looking at anticoagulation therapy in all Fontan patients are urgently needed.
authors.affiliation: Toronto General Hospital, University of Toronto, ON, Canada.
authors.forename: Chetan
authors.initials: C
authors.lastname: Varma
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Warr
authors.forename: Aaron L
authors.initials: AL
authors.lastname: Hendler
authors.forename: Narinder S
authors.initials: NS
authors.lastname: Paul
authors.forename: Gary D
authors.initials: GD
authors.lastname: Webb
authors.forename: Judith
authors.initials: J
authors.lastname: Therrien
mesh_terms: D000293:Adolescent; D000328:Adult; D015150:Echocardiography, Doppler; D005260:Female; D005500:Follow-Up Studies; D018729:Fontan Procedure / Q000009:adverse effects*; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D015995:Prevalence; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D014057:Tomography, X-Ray Computed