It is suggested that the elevated central venous pressure in patients with a Fontan circulation can provoke manifestation of lymphatic dysfunction, met as plastic bronchitis, peripheral oedema and most feared protein-losing enteropathy (PLE).

An explorative study from our department at Aarhus University Hospital revealed that the function of the lymphatic vasculature in 10 young Fontan patients with no complications was abnormal compared to healthy controls. However, to further describe and confirm these findings we had to investigate the lymphatic circulation in a larger, older and more complicated group of Fontan patients.

The hypothesis is that, patients with a univentricular circulation have a reduced functionality of the lymphatic vasculature and which predisposes them to developing complications such as edema and PLE.

The study population is patients with a Fontan circulation followed at InCor Heart Institute in Sao Paolo and Ribeirão Preto, Brazil. These were matched with and group of healthy controls.

The functional state of superficial lymphatics in the lower leg will be investigated, using near infrared fluorescence (NIRF) imaging. The capillary filtration of fluid and leakiness of the capillaries will be measured using strain gauge plethysmography and the peripheral blood flow will be measured using venous occlusion plethysmography. Furthermore, plasma concentration of noradrenaline will be estimated.

Inclusion Criteria:

• Fontan circulation
• Age above 16.

Exclusion Criteria:

• Mental illness
• Syndromes.

Patients born with a univentricular heart treated surgically with a Fontan circulation in early childhood.