Lung function, cardiopulmonary exercise capacity and lung perfusion in patients with corrected tetralogy of Fallot

Study objectives: Patients after total repair of tetralogy of Fallot (TOF) often have residual abnormalities of lung perfusion. It was suggested that interventions such as stenting of the stenotic vessels would improve exercise capacity. The purpose of the study was to compare lung function and cardiopulmonary functional capacity in patients with and without lung perfusion disturbances. Patients: Fifty patients (33 men, 17 women) of age 29 ± 11 years who were operated 8-10 years prior to the study. They were divided into two groups: 32 patients with normal lung perfusion and 18 patients with abnormal lung perfusion. Methods: Patients performed full lung function testing, progressive cardiopulmonary exercise, echo-Doppler assessments of pulmonary pressure, and quantitative perfusion ventilation. Results: Lung function: Patients post TOF show mild restriction (FVC = 80%) with normal oxygen saturation (97%) and six minute walking distance (600 m). Total lung capacity was slightly higher in the normal perfusion group 95 ± 15% vs. 85 ± 12% however; no statistical difference was seen between both groups. Echocardiography showed normal pulmonary pressure and normal LVEF (62%). Cardiopulmonary exercise showed mild limitation of exercise capacity with VO ₂ of 75-78% predicted in both groups. Conclusions: Patients post correction of TOP have mild restriction in their lung function, moderate limitation in their exercise capacity and normal pulmonary arterial pressure. As patients with abnormal lung perfusion scan have good exercise capacity, invasive intervention with angioplasty and/or stent insertion may not be justified.