Metabolic Remodeling in Fontan Patients

Congenital Heart Disease, Metabolism Disorder

Assessment of metabolic alterations in adult Fontan patients with a dominant left ventricle with the help of serum examinations (Metabolomics). The aim is to find a tool for the completion of the (semi-)invasive monitoring of Fontan hemodynamics.

Patients who are born with just one single heart chamber need to undergo surgical therapy allowing the single heart chamber to pump the blood into the systemic circulation and allowing the blood to flow passively to the lungs (Fontan circulation). Regular ultrasound, cardiopulmonary exercise testing, and invasive diagnostic tools (catheterization, general anaesthesia needed) are necessary to early find out cardiac, vascular, or circulatory impairment. It is still very difficult to diagnose and therapy failure of this Fontan system early enough. It is reported that in patients with a failing two-chambered heart, the energy source for the heart and the body in general switches from the use of lipids to the use of sugar and ketone bodies. First studies show decreased concentrations of membrane lipids in Fontan patients with a left dominant ventricle, and the energy metabolism has not been focused yet in those patients. The investigators hypothesize that there are differences in the pattern of the structural metabolism in adult Fontan patients with a left-dominant vs. a right-dominant ventricle. Furthermore the investigators hypothesize that there are alterations in the energy metabolism in adult Fontan patients in comparison to healthy two-chambered controls, and that those alterations correlate with the grade of impairment of cardiopulmonary function. With the help of a special biochemical examination (mass spectrometry-based Metabolomics study) blood of Fontan patients will be analyzed, and the results will be correlated with the results of ultrasound and cardiopulmonary exercise testing. The aim of this study is to establish sensitive blood markers indicating cardiac, vascular, circulatory or further organ dysfunction in Fontan patients. This should allow optimal Fontan system monitoring with an optimal timing of an additional invasive diagnostic catheterization and of nutritional, medical or interventional therapy.