No Synergic Effect of Sildenafil Administration on Exercise Capacity Improvement in a Fontan Patient with Regular Exercise Training

In Fontan patients, reduced exercise capacity due to diminished cardiac output is a common finding with important prognostic implications. Beneficial effects have been shown for sildenafil treatment and regular exercise, but data comparing both strategies is scarce. We report on a female patient with Fontan circulation who underwent repeated cardiopulmonary exercise tests with either placebo or a single dose of 50mg sildenafil before and after 6months of supervised aerobic and resistance exercise. At baseline, O2peak was 29.1ml/min/kg, and a marked increase to 32.8ml/min/kg was observed after administration of sildenafil. After the training period, O2peak was 34.5ml/kg/min in the placebo test, and no further increase by sildenafil was possible (33.7ml/kg/min). Similar results were observed for exercise capacity at the ventilatory anaerobic threshold. In summary, this Fontan patient showed that regular exercise might use up and probably exceed the acute sildenafil effects on exercise capacity. Exercise should be considered as a primary treatment strategy within secondary prevention and rehabilitation after the Fontan procedure.