Lymphatic Function in Patients With a Fontan-Kreutzer Circulation

Interventions: Diagnostic Test: Near Infrared Fluorescence Imaging
Diagnostic Test: Non-contrast MRI
Diagnostic Test: Strain Gauge Plethysmography

Brief Summary: The lymphatics regulate the interstitial fluid by removing excessive fluid. It represents an extremely important step in the prevention of edema. The Fontan-Kreutzer procedure has revolutionized the treatment of univentricular hearts. However, it is associated with severe complications such as protein-losing enteropathy (PLE) and peripheral edema that may involve the lymphatic circulation.

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

The functional state of lymphatics is investigated using near infrared fluorescence imaging, NIRF. The anatomy is described using non-contrast MRI and the capillary filtration rate is measured using plethysmography.

Detailed Description: Background:

The lymphatics regulate the interstitial fluid by removing excessive fluid. It represents an extremely important step in the prevention of edema. The Fontan-Kreutzer procedure has revolutionized the treatment of univentricular hearts. However, it is associated with severe complications such as protein-losing enteropathy (PLE) and peripheral edema that may involve the lymphatic circulation.

Hypothesis:

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

Material and Methods:

The functional state of lymphatics is investigated using near infrared fluorescence imaging, NIRF. The anatomy is described using non-contrast MRI and the capillary filtration rate is measured using plethysmography. The study population is patients with Fontan-Kreutzer circulation operated at Aarhus University hospital. Exclusion criteria is BMI\>30 and age (years) \< 18. The Fontan-Kreutzer group will be compared with an age, gender and weight matched control group of healthy volunteers.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Arm && Interventions

Group	Intervention	Description
Healthy Control subjects	Non-contrast MRI	Age, gender and weight matched control subjects
Healthy Control subjects	Near Infrared Fluorescence Imaging	Age, gender and weight matched control subjects
Fontan-Kreutzer operated patients	Non-contrast MRI	Patients with a Fontan-Kreutzer circulation. No interventions are done. (The intervention is the operation done 15-20 years ago)
Fontan-Kreutzer operated patients	Strain Gauge Plethysmography	Patients with a Fontan-Kreutzer circulation. No interventions are done. (The intervention is the operation done 15-20 years ago)
Healthy Control subjects	Strain Gauge Plethysmography	Age, gender and weight matched control subjects
Fontan-Kreutzer operated patients	Near Infrared Fluorescence Imaging	Patients with a Fontan-Kreutzer circulation. No interventions are done. (The intervention is the operation done 15-20 years ago)

Primary Outcome Measures

Name	Time	Method
Pumping pressure	1 hour	Occlusion of lymphatic flow by inflating a cuff (Hokanson E20 Rapid cuff inflator, Hokanson AG101 air source) to 70mmHg and then reducing the pressure with 5mmHg each 5th minute. The highest pressure under which the fluorescent dye is able to cross the inflatable cuff is labelled Ppump.
Contraction Frequency	6 min	Contraction frequency in vessels in the main drainage pathway of the legs (ventromedial bundle) as well as vessels draining the area behind the medial malleolus.
Refill time	20 min	The time it takes for a 10 cm long vessel to refill after emptying the vessel with massage
Velocity	6 min	The velocity measured in cm/s for a packet of lymph moving from one region of interest (ROI) to another through atlas a 5 cm straight vessel
Capillary Filtration Rate	25 min	A 5-step 20-min venous congestion protocol will be used to measure capillary filtration. The capillary filtration rate (µl·100 ml-1 ·min-1 ) is measured as the slope of the time-volume change (%) curve at steady state at the end of each pressure phase.

Secondary Outcome Measures

Name	Time	Method