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

Brief Title

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

Official Title

Vitamin C May Improve Endothelial Function and Exercise Capacity in Functional Single Ventricle Patients After Fontan Palliation

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.

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.

Study Type


Primary Outcome

Change in peak oxygen consumption (from baseline to post-study drug testing)

Secondary Outcome

 Oxygen Pulse


Fontan Procedure


Vitamin C

Study Arms / Comparison Groups

 Vitamin C
Description:  High-dose Vitamin C in 4 age-based doses will be given in two-daily doses for four weeks


* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.

Recruitment Information

Recruitment Status

Dietary Supplement

Estimated Enrollment


Start Date

June 2009

Completion Date

March 2010

Primary Completion Date

November 2009

Eligibility Criteria

        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




8 Years - 25 Years

Accepts Healthy Volunteers

Accepts Healthy Volunteers


John R Charpie, MD, , 

Location Countries

United States

Location Countries

United States

Administrative Informations



Organization ID


Responsible Party

Principal Investigator

Study Sponsor

University of Michigan


 Griese-Hutchinson Champions for Children's Hearts Investigator Award

Study Sponsor

John R Charpie, MD, Study Director, University of Michigan

Verification Date

May 2017