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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00974025
Recruitment Status : Completed
First Posted : September 10, 2009
Last Update Posted : June 1, 2017
Griese-Hutchinson Champions for Children's Hearts Investigator Award
Information provided by (Responsible Party):
John R. Charpie, University of Michigan

Brief Summary:
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 or disease Intervention/treatment Phase
Fontan Procedure Hypoplastic Left Heart Syndrome Tricuspid Atresia Dietary Supplement: Vitamin C Dietary Supplement: Placebo Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 53 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, 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
Study Start Date : June 2009
Actual Primary Completion Date : November 2009
Actual Study Completion Date : March 2010

Arm Intervention/treatment
Experimental: Vitamin C
High-dose Vitamin C in 4 age-based doses will be given in two-daily doses for four weeks
Dietary Supplement: 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
Dietary Supplement: Placebo
Placebo will be administered twice daily for four weeks

Primary Outcome Measures :
  1. Change in peak oxygen consumption (from baseline to post-study drug testing) [ Time Frame: 4 weeks ]

Secondary Outcome Measures :
  1. Oxygen Pulse [ Time Frame: 4 weeks ]
  2. Peak Work [ Time Frame: 4 weeks ]
  3. Endo-PAT score [ Time Frame: 4 weeks ]
  4. Framingham Modified Endothelial Function Score [ Time Frame: 4 weeks ]
  5. PedsQL 4.0 - quality of life assessment [ Time Frame: 4 weeks ]
  6. BNP [ Time Frame: 4 weeks ]

Information from the National Library of Medicine

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Ages Eligible for Study:   8 Years to 25 Years   (Child, Adult)
Sexes Eligible for Study:   All
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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00974025

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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
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Study Director: John R Charpie, MD University of Michigan
Principal Investigator: Bryan H Goldstein, MD University of Michigan
Publications of Results:
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: John R. Charpie, Professor, University of Michigan Identifier: NCT00974025    
Other Study ID Numbers: HUM00029464
First Posted: September 10, 2009    Key Record Dates
Last Update Posted: June 1, 2017
Last Verified: May 2017
Additional relevant MeSH terms:
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Hypoplastic Left Heart Syndrome
Tricuspid Atresia
Heart Defects, Congenital
Cardiovascular Abnormalities
Cardiovascular Diseases
Heart Diseases
Congenital Abnormalities
Heart Valve Diseases
Ascorbic Acid
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents