Effect of Sildenafil on Pressure–Volume Loop Measures of Ventricular Function in Fontan Patients

Ryan J. Butts, Shahryar M. Chowdhury, George H. Baker, Varsha Bandisode, Andrew J. Savage, Andrew M. Atz

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Sildenafil has been reported to improve exercise capacity in Fontan patients, but the physiologic mechanisms behind these findings are not completely understood. The objective of this study was to study the acute effect of sildenafil on pressure–volume loop (PVL) measures of ventricular function in Fontan patients. Patients after Fontan operation who were presenting for a clinically indicated catheterization were enrolled. Patients were randomized in a double-blinded fashion to receive placebo (n = 9) or sildenafil (n = 10) 30–90 min prior to catheterization. PVLs were recorded using microconductance catheters at baseline and after infusion of dobutamine (10 mcg/kg/min). The primary outcome was change in ventriculoarterial (VA) coupling. For the entire cohort, VA coupling trended toward improvement with dobutamine (1.4 ± 0.4 to 1.8 ± 0.9, p = 0.07). End-systolic elastance showed improvement (2.6 ± 0.9 to 3.8 ± 1.4 mmHg m2/ml, p < 0.01) with dobutamine infusion. The cohorts had similar VA coupling at baseline (p = 0.32), but the sildenafil cohort trended toward having less of an improvement in VA coupling with dobutamine stress (p = 0.06). There were no differences between PVL measures of systolic or diastolic function between treatment groups, both at baseline and after dobutamine infusion. Patients with Fontan circulation had improved contractility and trended toward improvement in VA coupling with dobutamine stress. Acute sildenafil administration was not associated with improved PVL measurements of ventricular function in this population. These results suggest that clinical improvements seen with administration of sildenafil in Fontan patients are not associated with an acute improvement in ventricular function. Clinical Trial Registration: www.clinicaltrials.gov; Clinicaltrials.gov Identifier: NCT01815502.

Original languageEnglish (US)
Pages (from-to)184-191
Number of pages8
JournalPediatric Cardiology
Issue number1
StatePublished - Jan 1 2016


  • Fontan
  • Pressure–volume loop
  • Sildenafil
  • Single-ventricle heart disease

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Cardiology and Cardiovascular Medicine


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