title: Predictors of sildenafil effects on exercise capacity in adolescents and adults with Fontan circulation.
abstract: OBJECTIVE
  A single dose of sildenafil improves exercise capacity in Fontan patients. However, a recent study failed to show a long-term effect of sildenafil. This study evaluated whether there are factors that might predict sildenafil effects.
  
  
  METHODS
  We studied 36 patients (16-42 years, 14 female) with univentricular heart after various modifications of the Fontan surgery (13 APC, 16 AVC, 7 TCPC). They performed two cardiopulmonary exercise tests, with at least 120 min rest and a single dose of 50 mg sildenafil in between.
  
  
  RESULTS
  After sildenafil administration, patients improved their peak oxygen uptake from 64.5 to 67.3 % predicted (p = 0.0003) without change in ventilatory efficiency ([Formula: see text] slope), oxygen saturation (SpO2) at rest or at peak exercise, respiratory exchange ratio. In addition, resting systolic blood pressure was slightly reduced after sildenafil administration. There was a moderate negative correlation of this improvement to baseline peak oxygen uptake (r = -0.395; p = 0.017). The change in peak oxygen uptake could not be correlated to time of surgery, type of surgery, NT-pro-BNP, or to other clinical data. Nevertheless, all four patients with NT-pro-BNP levels higher than 1,000 pg/ml had the most prominent improvements in exercise capacity.
  
  
  CONCLUSIONS
  Fontan patients have an improved exercise capacity after a single dose of sildenafil. Patients with worse baseline peak oxygen uptake profit more.
authors.affiliation: Department of Pediatric Cardiology and Congenital Heart Disease, Deutsches Herzzentrum München, Technische Universität München, Lazarettstr. 36, 80636, Munich, Germany, a-hager@web.de.
authors.forename: Alfred
authors.initials: A
authors.lastname: Hager
authors.forename: Ruth
authors.initials: R
authors.lastname: Weber
authors.forename: Jan
authors.initials: J
authors.lastname: Müller
authors.forename: John
authors.initials: J
authors.lastname: Hess
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects*; D005260:Female; D018729:Fontan Procedure; D006330:Heart Defects, Congenital / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010446:Peptide Fragments / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D000068677:Sildenafil Citrate; D013449:Sulfonamides / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D010446:Peptide Fragments; D010879:Piperazines; D011687:Purines; D013449:Sulfonamides; D014665:Vasodilator Agents; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D000068677:Sildenafil Citrate