title: When is the right time for Fontan conversion? The role of cardiopulmonary exercise test.
abstract: BACKGROUND
  To determine if Fontan conversion (FC) resulted in improvement in exercise capacity (EC), and to determine the role of cardiopulmonary exercise test (CPET) in risk stratification of patients undergoing FC.
  
  
  METHODS
  A retrospective review of patients who underwent CPET prior to FC at Mayo Clinic from 1994 to 2014. The patients who also underwent post-operative CPET were selected for the analysis of improvement in EC defined as 10% increase in baseline peak oxygen consumption (VO2).
  
  
  RESULTS
  75 patients CPET prior to FC; mean age 24±6years; 44 males (59%); and 51 (68%) were in NYHA III/IV prior to FC. Pre-operative peak VO2 was 15.5±3.4ml/kg/min. A comparison of pre- and post-FC CPET data was performed using 42 patients (56%) that underwent CPET after FC. Improvement in EC occurred in 18 of 42 patients (43%). Baseline peak VO2 >14ml/kg/min was associated with improved EC (hazard ratio [HR] 1.85; P=.02). Improvement in New York Heart Association (NYHA) class occurred in 12 (67%) patients with improved EC vs 2 (8%) without improved EC. Improvement in NYHA class was more likely to occur in patients with improved EC compared to those without improvement EC (odds ratio 4.11, P=.01). There were 10 (13%) perioperative deaths, and baseline peak VO2 ≤14ml/kg/min was predictive of perioperative mortality (HR 3.74; P<.001).
  
  
  CONCLUSIONS
  Baseline peak VO2 was predictive of perioperative survival, and improvement in EC. Performance on CPET in failing Fontan patients might be a useful clinical parameter in determining appropriate timing of FC.
authors.affiliation: Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. Electronic address: egbe.alexander@mayo.edu.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Egbe
authors.affiliation: Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. Electronic address: connolly.heidi@mayo.edu.
authors.forename: Heidi M
authors.initials: HM
authors.lastname: Connolly
authors.affiliation: Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA. Electronic address: jdearani@mayo.edu.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Dearani
authors.affiliation: Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Crystal R
authors.initials: CR
authors.lastname: Bonnichsen
authors.affiliation: Department of Pediatrics, Mayo Clinic, Rochester, MN, USA. Electronic address: niaz.talha@mayo.edu.
authors.forename: Talha
authors.initials: T
authors.lastname: Niaz
authors.affiliation: Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. Electronic address: allison.thomas@mayo.edu.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Allison
authors.affiliation: Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA. Electronic address: johnson.jonathan@mayo.edu.
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Johnson
authors.affiliation: Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Poterucha
authors.affiliation: Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA. Electronic address: said.sameh@mayo.edu.
authors.forename: Sameh M
authors.initials: SM
authors.lastname: Said
authors.affiliation: Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. Electronic address: ammash.naser@mayo.edu.
authors.forename: Naser M
authors.initials: NM
authors.lastname: Ammash
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005080:Exercise Test / Q000379:methods* / Q000401:mortality / Q000639:trends; D005260:Female; D018729:Fontan Procedure / Q000379:methods* / Q000401:mortality / Q000639:trends; D018610:Heart Bypass, Right / Q000401:mortality / Q000639:trends; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D019990:Perioperative Care / Q000379:methods* / Q000401:mortality / Q000639:trends; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D055815:Young Adult
keywords: Cardiopulmonary exercise test; Exercise capacity; Fontan conversion