Good exercise tolerance and impaired lung function after atrial repair of transposition

Evaluation of long-term results of atrial correction of transposition of the great arteries (TGA), focusing on the relationship between pulmonary function and exercise tolerance.

A prospective population-based study-56 out of 60 survivors of Mustard/Senning repair, born in Bohemia in 1980-1984 (median age at surgery 0.85 years) were followed up over 13.4 +/- 1.2 years and studied by complete lung function and bicycle exercise testing.

Maximum heart rate on exercise reached 181 +/- 14 bpm (Z-score: -1.06 +/- 1.66, range -6.7 to +1.6); VO2max: 40.6 +/- 6.7 ml/kg per min (Z-score: -0.97 +/- 1.4, range -5 to +1.8). A total of 73.6% had abnormal lung function, most frequently features of stiff lung (39.6%) and lung restriction (32.1%). Static recoil pressure of the lungs measured at 100, 90 and 60% of total lung capacity reached 137, 126 and 130%, respectively (Z-score: 1.93 +/- 2.33, 1.64 +/- 1.96, and 1.14 +/- 1.95, respectively). There was an inverse relationship between static recoil pressure of the lungs and VO2max (r = -0.306, P = 0.043), indicating the impact of lung function abnormalities on exercise tolerance. Comparison with lung function study of the group of 'pioneer' Mustard patients operated at the mean age of 4.4 years revealed a similar pattern and frequency (73.6% in current series vs. 88%, NS).

Long-term follow-up has shown good exercise tolerance in the majority of patients after atrial correction of TGA performed in infancy. Many of them, however, have impaired lung function, especially stiff lung, although less frequently than original patients operated at a later age. The stiff lung can impair the exercise tolerance.