Mid-Term Follow-Up after Arterial Switch Operation for Complete Transposition of the Great Arteries

Abstract

Purpose : Transposition of the Great Arteries has to be surgically corrected by an arterial switch operation. This complex surgical procedure has the potential for significant short- and long-term complications like dilation of the neo-aortic root, coronary and pulmonary artery (PA) stenosis. The aim was to determine a suitable follow-up algorithm for mid-term follow-up. Material and Methods : 26 patients (mean age 10±2 years) were examined using echocardiography, ECG-gated Computed Tomography Angiography (CTA) and functional Magnetic Resonance Imaging (MRI) with flow, cine and pulmonary perfusion measurements. Results : CTA was capable to visualize coronary arteries in all cases. Coronary stenosis did not occur. Echocardiography failed to visualize the coronary arteries in 81%. CTA revealed moderate PA stenosis (25-50% lumen reduction) in 41% and severe stenosis (>50%) in10%. Visualization of pulmonary arteries was possible by echocardiography in only 45%. Correlation between MR-pulmonary perfusion abnormalities and PA stenosis were not present. Doppler-echocardiography showed mild flow acceleration in the main PA (mean pressure gradient 34mmHg) in 4 patients, while MRI found an increased velocity in 9 patients. 10 patients had neo-aortic root dilatation detected with CTA. On echocardiography 8 patients had mild, 4 had moderate aortic valve insufficiency. On MRI amount of aortic valve insufficiency was too small to be quantified. Conclusion : Branch stenosis of the PA was the leading complication 10 years after surgery, coronary stenosis did not occur. Value of Echocardiography is minor in the visualization of coronary arteries and PA morphology and it is recommended only for the assessment of cardiac and valvular function. Additionally, CTA is method of choice for visualization of coronary arteries and PA morphology. In this study the value of MRI for assessment of the complete morphology was limited, but improves with technical advance.