Abstract 14917: Premature Aortic Stiffening in Patients with Transposition of the Great Arteries after Arterial Switch Operation
Introduction: The elastic buffering function of the transposed aorta after arterial switch operation (ASO) is suspected to be an important determinant for long-term prognosis. The goal of this study was a comprehensive assessment of the bioelastic properties of the aorta after ASO in children and adults with transposition of the great arteries (TGA).
Methods: 51 patients and 34 age-matched controls were studied at 3.0 Tesla with cardiovascular magnetic resonance imaging (CMR). 43 patients (mean age 12.8±6.9 years) underwent one-stage ASO, 8 patients (mean age 23.8±6.9 years) had prior banding of the pulmonary artery (two-stage ASO). CMR data were used to study aortic dimensions, aortic distensibility, and pulse wave velocity (PWV), and their relation to age, left ventricular (LV) volumes, mass and function.
Results: Compared to age-matched controls, patients had increased areas of the aortic root (one-stage ASO: 605.8±206.1 vs. 409.1±101.6 mm2/m2, two-stage ASO: 864.0±312.6 vs. 397.0±67.6 mm2/m2; p<0.01) and significantly reduced distensibility of the aortic root (one- stage ASO: 3.4±2.1 vs. 9.1±4.7 10-3 mm Hg-1, two-stage ASO: 1.9±1.0 vs. 7.7±2.7 10-3 mm Hg-1; p<0.01), the ascending aorta (one-stage ASO: 4.8±3.1 vs 10.8±5.5 10-3 mm Hg-1, two-stage ASO: 2,5±0.5 vs. 7.5±1.8 10-3 mm Hg-1; p<0.01) and the descending aorta (one-stage ASO: 7.6±3.3 vs. 9.05±5.1; p=0.049). PWV was found to be significantly higher in two-stage ASO (5.3±1.0 vs. 3.5±0.6 m/s, p<0.01). LV mass was higher in patients than in controls (56.5±22.3 vs. 48.2±8.6 g/m2; p<0.05). In contrast to controls, PWV and aortic root distensibility showed a strong correlation with age (r=0.59, p<0.001 and r=-0.4, p<0.01).
Conclusions: TGA patients post ASO showed impaired bioelastic properties of the aorta and aortic root dilatation suggesting structural aortic wall abnormalities. Impairment of the aortic bioelastic properties was strongly associated with age. Increased aortic stiffness is known to be an important cardiovascular risk factor, suggesting that the bioelastic properties of the aorta, and possibly early manifestations of adverse aortic-ventricular coupling, should be routinely monitored after ASO.
- © 2011 by American Heart Association, Inc.