Abstract 16301: Mechanisms of Coronary Complications Following the Arterial Switch for Transposition of the Great Arteries
The arterial switch operation (ASO) for transposition of the great arteries (TGA) requires transfer the coronary arteries from the aorta to the proximal pulmonary artery (neo-aorta). This is complicated by the variable coronary anatomy prior to transfer. In 8-10% of cases, there is evidence of late coronary stenosis and/or occlusion, often with catastrophic clinical consequences. The mechanism of such complications has not been well studied. We analyzed 193 consecutive high resolution CT scans from the ASO procedure (patients aged 2 months to 16 years) and found 17 patients with significant (>30% until occlusion) coronary lesions (8.8%); all were later confirmed by conventional angiography. The left main coronary artery was abnormal in 9 patients (ostium in all); the left anterior descending artery in 3, the circumflex in 2, the right coronary artery in 3 patients. Using multiplanar and 3D reconstructions of the coronary arteries, aorta and pulmonary artery, we identified the commonest mechanisms of coronary abnormalities. For the left main and left anterior descending artery, anterior positioning of the transferred left coronary artery (between 12 and 1 o'clock on the neo-aorta) predisposed to compression by the pulmonary artery. All circumflex lesions occurred in Yacoub-type D coronaries where a long initially retroaortic artery was stretched by its new positioning behind an enlarged neo-aorta. Right coronary artery lesions occurred only in cases where the reimplantation site was very high above the right coronary sinus with potential compression from the main pulmonary artery bifurcation immediately above. Thus detailed multiplanar CT scanning can elucidate the mechanisms of late coronary complications after the ASO. Understanding these aspects could inform surgical technique to minimize the risk of these important late complications.
- © 2010 by American Heart Association, Inc.