title: Diagnosis of occult diastolic dysfunction late after the Fontan procedure using a rapid volume expansion technique.
abstract: Diastolic dysfunction (DD), a key driver of long-term Fontan outcomes, may be concealed during standard haemodynamic evaluation. We sought to identify Fontan patients with occult DD using 'ventricular stress testing' with rapid volume expansion (RVE).
  
  
  
  Cardiac catheterisation with RVE was performed routinely in Fontan patients between 11/2012 and 4/2015. Baseline and post-stress haemodynamic data were compared using t test, Mann-Whitney U test, χ(2) and Fisher's exact tests. A post-stress ventricular end diastolic pressure (EDP) threshold of 15 mm Hg defined occult DD.
  
  
  
  Forty-six Fontan patients (48% female, median age 14.1 (IQR 9.1 to 21.3) years) were included. The median Fontan duration was 10.8 (IQR 5.1 to 17.8) years and dominant left ventricular morphology was present in 63% of patients. Volume expansion increased mean Fontan pressure (15.2±2.5 vs 12.4±2.2 mm Hg, p<0.001), pulmonary capillary wedge pressure (11.3±2.6 vs 7.9±2 mm Hg, p<0.001) and EDP (12.7±3.3 vs 8.5±2.1 mm Hg, p<0.001). Sixteen patients (35%) had occult DD, demonstrating higher baseline EDP (10.3±1.9 vs 7.6±1.5 mm Hg, p<0.001) and greater increase in EDP (6.3±2.4 vs 3.1±1.4 mm Hg, p<0.001) compared with patients without DD. Higher baseline EDP, lower baseline cardiac index and longer duration of Fontan circulation were associated with higher post-stress EDP. There were no complications related to RVE.
  
  
  
  Ventricular stress testing by RVE is feasible, safe and identifies a subgroup of Fontan patients with occult DD. Higher baseline EDP and longer duration of Fontan circulation are associated with worse diastolic function. Future work is necessary to better understand the aetiology, associations and clinical implications of occult DD in Fontan survivors.
authors.affiliation: The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Averin
authors.affiliation: The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Russel
authors.initials: R
authors.lastname: Hirsch
authors.affiliation: Department of Pediatrics (Cardiology), University of Arizona, Tucson, Arizona, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Seckeler
authors.affiliation: The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Wendy
authors.initials: W
authors.lastname: Whiteside
authors.affiliation: The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Beekman
authors.affiliation: The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Bryan H
authors.initials: BH
authors.lastname: Goldstein
mesh_terms: D000293:Adolescent; D006328:Cardiac Catheterization / Q000379:methods*; D016009:Chi-Square Distribution; D002648:Child; D003971:Diastole; D005240:Feasibility Studies; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects*; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D018754:Ventricular Dysfunction / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D016276:Ventricular Function; D017725:Ventricular Pressure; D055815:Young Adult