Acute Effects of Inhaled Treprostinil in Fontan Patients

A Randomized, Placebo-Controlled Pilot Study to Determine the Acute Effects of Inhaled Treprostinil on Exercise, Vascular Function, and Exercise Induced Liver Stiffness in Fontan Patients

In this pilot study investigators propose to explore the effects of a locally delivered inhaled pulmonary vasodilator (inhaled treprostinil) on exercise performance, pulmonary blood flow, venous pressure response and vascular function in stable Fontan patients. Investigators will also assess the effects of resting and acute rises in exercise induced systemic venous pressure on liver stiffness and will also assess whether treprostinil will attenuate the acute stiffness increase that investigators expect to see. This will be a prospective, randomized, double-blinded placebo controlled, crossover trial. Following recruitment and informed consent, each participant will undergo three study visits, including baseline testing (visit 1), followed by two sets of exercise and vascular function tests (visit 2 and visit 3) at CCHMC. Twenty-six patients will be enrolled in this study.

Inclusion Criteria:

1. Patients age 18 years and older
2. Single ventricle patients status post Fontan procedure

Exclusion Criteria:

1. Clinically unstable: these are patients who are experiencing new cardiovascular symptoms such as worsening shortness of breath, new onset arrhythmia, uncontrolled heart failure, or evidence of clinically significant cirrhosis or renal failure.
2. Evidence of Fontan pathway or intra cardiac obstruction as identified on prior clinically indicated imaging studies (echocardiography and MRI);
3. Evidence of left or right systemic ventricular systolic dysfunction with an Ejection fraction of <40% on either echocardiogram or MRI from previously documented clinical data;
4. Presence of uncontrolled arrhythmias;
5. Unable to perform exercise testing for any reason or if deemed by the PI or designee that exercise testing would not be in the best interest of the participant
6. Currently pregnant and/or breastfeeding
7. Patient unable to provide informed consent
8. BMI > 30 mg/m2