Impact of Vitamin C on Endothelial Function and Exercise Capacity in Fontan-Palliated Patients

This study has been completed.
Griese-Hutchinson Champions for Children's Hearts Investigator Award
Information provided by:
University of Michigan Identifier:
First received: September 9, 2009
Last updated: October 20, 2011
Last verified: September 2009
In this study, investigators will evaluate the effect of vitamin C on endothelial function, exercise tolerance and quality of life in patients with a single ventricle who have been palliated to Fontan physiology. The hypothesis is that vitamin C will result in improved exercise tolerance and endothelial function in patients who have undergone the Fontan operation, compared to placebo.

Condition Intervention
Fontan Procedure
Hypolpastic Left Heart Syndrome
Tricuspid Atresia
Drug: Vitamin C
Drug: Placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Vitamin C May Improve Endothelial Function and Exercise Capacity in Functional Single Ventricle Patients After Fontan Palliation

Resource links provided by NLM:

Further study details as provided by University of Michigan:

Primary Outcome Measures:
  • Change in peak oxygen consumption (from baseline to post-study drug testing) [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Oxygen Pulse [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
  • Peak Work [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
  • Endo-PAT score [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
  • Framingham Modified Endothelial Function Score [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
  • PedsQL 4.0 - quality of life assessment [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
  • BNP [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]

Enrollment: 53
Study Start Date: June 2009
Study Completion Date: March 2010
Primary Completion Date: November 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Vitamin C
High-dose Vitamin C in 4 age-based doses will be given in two-daily doses for four weeks
Drug: Vitamin C
High-dose Vitamin C will be administered in 4 age-based dosing groups
Placebo Comparator: Placebo
Placebo will be given in two-daily doses for four weeks
Drug: Placebo
Placebo will be administered twice daily for four weeks

Detailed Description:
Recent evidence suggests that after Fontan operation, single ventricle patients have impaired function of the vascular endothelium due in part to abnormalities in nitric oxide signaling. Endothelial dysfunction may contribute to the development of congestive heart failure and exercise intolerance that have been well-documented in Fontan patients. Therapeutic interventions to improve endothelial function in adults with heart failure have mainly focused on increasing the synthesis or decreasing the degradation of nitric oxide. We propose a randomized, prospective, placebo-controlled trial of vitamin C, an antioxidant that protects NO deactivation, in subjects with single ventricular anatomy after Fontan palliation. The specific aims of this study are to compare NO signaling, endothelial function and exercise capacity in Fontan subjects to that of a control group that is frequency-matched to case subjects by age and sex, and to assess NO signaling, endothelial function and exercise capacity in Fontan subjects after 4 weeks of oral vitamin C (or placebo) therapy. These results have particular importance because improving the endothelial response in Fontan patients has the potential to reduce the risk of developing congestive heart failure and improve exercise capacity. Furthermore, assessing endothelial function and the effects of therapies aimed at improving vascular health may be generalizable to many other chronic pediatric conditions associated with increased cardiovascular risk such as obesity, diabetes mellitus, and hypertension.

Ages Eligible for Study:   8 Years to 25 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • 8-25 years of age
  • Fontan-palliated patient

Exclusion Criteria:

  • New York Heart Association (NYHA) classes III or IV
  • Diabetes mellitus
  • Family history of premature coronary artery disease
  • Use of Sildenafil or other pulmonary artery vasodilators
  • Prior cardiac arrest (outside the first 24-hours postoperatively)
  • Life-threatening dysrhythmias
  • Severe ventricular dysfunction
  • Severe AV valve regurgitation
  • Pregnancy
  • Severe renal or hepatic impairment
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Please refer to this study by its identifier: NCT00974025

United States, Michigan
University of Michigan
Ann Arbor, Michigan, United States, 48109
Sponsors and Collaborators
University of Michigan
Griese-Hutchinson Champions for Children's Hearts Investigator Award
Study Director: John R Charpie, MD University of Michigan
Principal Investigator: Bryan H Goldstein, MD University of Michigan
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: John R. Charpie, University of Michigan Health System Identifier: NCT00974025     History of Changes
Other Study ID Numbers: HUM00029464 
Study First Received: September 9, 2009
Last Updated: October 20, 2011
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Tricuspid Atresia
Cardiovascular Abnormalities
Cardiovascular Diseases
Congenital Abnormalities
Heart Defects, Congenital
Heart Diseases
Heart Valve Diseases
Ascorbic Acid
Growth Substances
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Protective Agents processed this record on May 25, 2016