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Exercise ability after Mustard's operation
J J Bowyer1, C M Busst, J A Till
1Brompton Hospital, London, Department of Paediatrics.
Insights
Formal exercise testing in children after Mustard's operation for transposition of the great arteries reveals exercise limitations linked to venous obstruction or pulmonary vascular disease. This testing identifies hemodynamic abnormalities needing intervention.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Surgery
- Exercise Physiology
Background:
- The Mustard operation is a palliative procedure for transposition of the great arteries (TGA).
- Long-term outcomes and exercise capacity in children post-Mustard operation require further investigation.
- Identifying subclinical hemodynamic abnormalities is crucial for timely intervention.
Purpose of the Study:
- To assess exercise tolerance and identify hemodynamic abnormalities in children years after Mustard's operation.
- To correlate exercise capacity with specific anatomical or physiological complications.
- To evaluate the utility of formal exercise testing in this patient population.
Main Methods:
- Twenty children (6-12 years post-op) underwent maximal treadmill testing with gas exchange and ECG.
- Nineteen children had cardiac catheterization to measure oxygen consumption and calculate pulmonary and systemic blood flow.
- Exercise data was compared to 20 age and size-matched healthy controls.
Main Results:
- Seven patients had normal exercise tolerance (>40 ml/kg/min VO2 max).
- Ten patients showed moderate reduction (30-39 ml/kg/min VO2 max), and three had severe limitations.
- Obstruction of venous return was associated with impaired exercise ability, while severe limitations correlated with pulmonary vascular disease and outflow tract obstruction.
Conclusions:
- Formal exercise testing effectively identifies children with reduced exercise capacity after Mustard's operation.
- Hemodynamic abnormalities, including venous obstruction and pulmonary vascular disease, significantly impact exercise tolerance.
- Exercise testing can guide interventions for children with potentially asymptomatic cardiovascular compromise post-TGA repair.
Abstract:
Twenty children who were well six to 12 years after undergoing Mustard's operation for transposition of the great arteries were studied. Each child performed a graded maximal treadmill test with measurements of gas exchange and oxygen saturation, and had electrocardiography carried out. Nineteen were also catheterised, and oxygen consumption was measured so that pulmonary and systemic flow could be calculated. Compared with 20 age and size matched controls, seven of the patients had normal exercise tolerance (as judged by a maximal oxygen consumption of greater than 40 ml/kg/min), 10 showed a moderate reduction (30-39 ml/kg/min), and three were more seriously limited. None of the patients with normal exercise tolerance had obstruction of venous return but six of those with mild impairment of exercise ability had partial or complete obstruction of one or both of the vena cavas. More severe limitation was associated with pulmonary vascular disease and fixed ventricular outflow tract obstruction. Formal exercise testing of apparently well children who have undergone Mustard's operation identifies those with haemodynamic abnormalities that may require intervention.