Tadalafil and Exercise Capacity after Fontan Operation

Background: Patients with congenital heart defects that have single functional ventricle undergo Fontan surgery. After the surgery, patients will develop reduced capacity for physical activity and exercise. Phosphodiesterase inhibitor drugs have vasodilatory effects and can decrease blood flow resistance. Thereby, they can help to improve the exercise capacity of patients. The aim of this study was to assess the effect of tadalafil on exercise capacity in these patients. Materials and Methods: In this before and after interventional study, 16 patients who had undergone Fontan operation were treated with tadalafil (10 mg daily for 2 weeks and then 10 mg every 12 h for 6 months). Demographic data, heart disease morphology, pulse oximetry, blood pressure (BP), functional class, age at the time of surgery, and the surgery type were collected. Pulmonary function and exercise capacity were assessed by 6‑min walk test and VO2 max (maximal oxygen consumption). Results: Mean distance based on 6‑min walk test increased from 418.75 m to 439.06 m (P = 0.004). Mean maximal oxygen consumption increased from 0.84 L/min to 1.07 L/min (P 0.001). Furthermore, preexercise test oxygen saturation increased from 89% to 90.94% (P = 0.02). No significant change was observed regarding other variables. Conclusion: Tadalafil was found to be effective in improving exercise capacity of the patients with a previous history of Fontan surgery. However, tadalafil had no significant effect on systolic or diastolic BP and heart rate.