Exercise capacity in patients with repaired Tetralogy of Fallot aged 6 to 63 years

Abstract

Objectives This study aimed to provide a perspective for the interpretation of exercise capacity (peakVO 2 ) in patients with repaired Tetralogy of Fallot (patients with rTOF) by describing the course of peakVO 2 from patients aged 6–63 years. Methods A retrospective study was performed between September 2001 and December 2016 in the German Heart Centre Munich, Germany, and in the University Medical Centre Groningen, the Netherlands. A total of 1175 cardiopulmonary exercise tests (CPETs) were collected from 586 patients with rTOF, 46% female. Maximal exertion was verified using a respiratory exchange ratio ≥1.00. PeakVO 2 was modelled using time-dependent multilevel models for repeated measurements (n=889 in 300 patients), and compared with subject-specific reference values calculated by the models of Bongers et al and Mylius et al. Results The peakVO 2 of patients with rTOF was reduced at all ages. At the age of 6, the peakVO 2 was 614 mL/min (70% of predicted (95% CI 67 to 73)). The reduced increase in peakVO 2 during adolescence resulted in a significant lower maximum peakVO 2 of 1209 mL/min at 25 years (65% predicted, p<0.001). A linear decline after 25 years was observed in patients and references, although patients showed an accelerated decline, with a -0.24% point of predicted (95% CI 0.11 to 0.38) per year without differences between sexes (p=0.263). Conclusions This study provides a context for peakVO 2 across ages in patients with rTOF under contemporary treatment strategies. It showed that the reduction in peakVO 2 originates from childhood and declines over time. Sex differences in patients with rTOF were similar to natural existing sex differences.