Warmerdam EG, Magni F, Leiner T, Doevendans PA, Sieswerda GT, van
Wijk SW, Breur HM, Driesen BW, Grotenhuis HB, Takken T.

J Cardiol. 2020 May 10. pii: S0914-5087(20)30105-2. doi:
10.1016/j.jjcc.2020.02.025. [Epub ahead of print]

BACKGROUND: The arterial switch operation (ASO) for transposition of the great
arteries has excellent survival, but a substantial number of patients suffer from
a reduced exercise capacity. The goal of this study was to identify imaging
parameters associated with a reduced exercise capacity in patients after ASO.
METHODS: A retrospective analysis was performed of ASO patients who underwent
cardiopulmonary exercise testing (CPET) between 2007 and 2017. Reduced exercise
performance was defined as a reduced workload peak (Wpeak) with Z-score <-2 or a
peak oxygen uptake indexed for weight (VO2peak/kg) with Z-score <-2. Data on
echocardiography and cardiac magnetic resonance performed within 1 year of the
CPET were collected for comparison.
RESULTS: A total of 81 ASO patients (age 17±7 years) were included. Reduced
exercise performance was found in 22 patients (27%) as expressed by either a
reduced Wpeak and/or a reduced VO2peak/kg. Main pulmonary artery gradient and
tricuspid regurgitation gradient by echocardiography were found to be associated
with reduced Wpeak (p=0.031; p=0.020, respectively). The main pulmonary artery
gradient and tricuspid regurgitation gradient by echocardiography were found to
be associated with reduced VO2peak/kg (p=0.009; p=0.019, respectively). No left
ventricular parameters were found to be associated with abnormal exercise
performance.
CONCLUSION: This study demonstrates that ASO patients frequently experience
reduced exercise capacity. Echocardiographic evidence of main pulmonary artery
stenosis and increased right ventricular pressure were associated with reduced
exercise capacity, and are therefore key to monitor during serial follow-up of
ASO patients.