Functional Capacity Is Affected by Younger Age of Repair in Tetralogy of Fallot Patients But Not by Era of Repair

Background: Cardiopulmonary exercise testing is widely used to assess functional capacity in patients with tetralogy of Fallot after surgical repair. Little is known regarding the impact of age at the time of primary complete repair and surgical era effect on exercise capacity.

Methods: A retrospective, single-center chart review was done from 1976 to 2016 on pediatric patients with tetralogy of Fallot who underwent cardiopulmonary exercise testing with cycle ergometry utilizing the James protocol and were then sorted by repair before/after 1990 and by age of complete repair before/after one year. Exclusion criteria included submaximal tests, incomplete data, previous pulmonary valve replacement, and surgery prior to complete repair (ie, Blalock-Taussig shunt placement).

Results: When comparing the groups who underwent primary complete repair before (N = 39) and after (N = 26) one year of age, the younger group demonstrated a higher percentage of predicted peak oxygen consumption ($\dot{\text{V}}$ o ₂peak; 83.1% ± 11.8% vs 73.1% ± 16.1%; P = .005) despite having worse pulmonary insufficiency at the time of exercise testing. There were no differences in heart rate and blood pressure response. Age of repair was independently associated with $\dot{\text{V}}$ o ₂peak. Data were statistically similar to the study eras (repair before 1990, N = 23; repair after 1990, N = 65): percentage of predicted $\dot{\text{V}}$ o₂peak (81.4% ± 13.6% vs 79.1% ± 14.4%, P = .5), maximal systolic blood pressure (155.1 ± 22.4 mm Hg vs 153.9 ± 17 mm Hg, P = .8), and percentage of predicted maximal heart rate (89.8% ± 9% vs 92% ± 7.1%, P = .3).

Conclusions: Older age at primary repair appears to negatively impact $\dot{\text{V}}$ o₂peak; however, era effect does not appear to influence cardiopulmonary exercise testing outcomes.