Lymphatic Function in Patients With Fontan Circulation: Effect of Physical Training

Background: The Fontan operation has been used to treat complex cardiac anomalies with a single-functioning ventricle. A study performed by Instituto do Coracão-Hospital das Clínicas-Universidade de Sao Paulo (InCor/HCFMUSP)-Brazil, Hospital das Clínicas of Ribeirão Preto-Brazil, department of the University of Aarhus, and Rigshospitalet, Denmark demonstrated an impairment peripheral lymphatic function in Fontan patients compared with healthy controls. However, the ability to increase the frequency of contractions is impaired when stressed by hyperthermia. Lymph vessels in Fontan patients were unable to respond usually. The participants were only able to increase the frequency of contraction twice during stress, compared to a five-fold increase among healthy controls. At the microcirculation level, Fontan patients filtered less fluid into the capillaries interstitial space than healthy controls at venous occlusion pressure. Studies carried out at InCor/HCFMUSP demonstrated that supervised aerobic exercise training improves the functional capacity and neurovascular control in Fontan patients compared to the non-training control group. However, the effect of aerobic exercise and light muscle resistance performed through online rehabilitation has not yet been demonstrated in peripheral lymphatic function and microcirculation. Aim: Evaluate the effects of an aerobic and light muscle resistance exercise program on peripheral lymphatic function, capillary filtration, functional capacity, and quality of life in adults with Fontan circulation. Methods: The function of the superficial lymphatic vessels in the lower leg will be investigated during rest in supine and standing positions, using near-infrared fluorescence imaging using Indocyanine Green (ICG; Verdye, Diagnostic Green GmbH, Germany). The variables analyzed are contraction frequency (contraction/minute), pumping Pressure (mmHg), and packet velocity. Venous congestion plethysmography will perform to analyze the capi