Mechanisms of coronary complications after the arterial switch for transposition of the great arteries.
BACKGROUND
The arterial switch operation (ASO) for transposition of the great arteries requires transfer of the coronary arteries from the aorta to the proximal pulmonary artery (neoaorta). This is complicated by variable coronary anatomy before transfer. In 8% to 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.


RESULTS
We analyzed 190 consecutive high-resolution computed tomographic scans from the ASO procedure (patients aged 5-16 years) and found 17 patients with significant (>30% up to occlusion) coronary lesions (8.9%); 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, and the right coronary artery in 3 patients. Using multiplanar and 3-dimensional 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 neoaorta) appeared to predispose to a tangential course of the proximal left coronary artery promoting stenosis. All circumflex lesions occurred in Yacoub type D coronaries where a long initially retroaortic artery was stretched by its new positioning behind an enlarged neoaorta. Right coronary artery lesions occurred only in cases in which the reimplantation site was very high above the right coronary sinus with potential compression from the main pulmonary artery bifurcation immediately above.


CONCLUSIONS
Thus detailed multiplanar computed tomographic scanning can elucidate the mechanisms of late coronary complications after the ASO. Understanding these aspects could help to improve surgical technique to minimize the risk of late coronary obstructions.
Hôpital Necker-Enfants Malades, AP-HP, University Paris-Descartes, Paris, France. phalla.ou@nck.aphp.fr
Phalla
P
Ou
Diala
D
Khraiche
David S
DS
Celermajer
Gabriella
G
Agnoletti
Kim-Hanh
KH
Le Quan Sang
Jean Christophe
JC
Thalabard
Mathieu
M
Quintin
Olivier
O
Raisky
Pascal
P
Vouhe
Daniel
D
Sidi
Damien
D
Bonnet
D000293:Adolescent; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D017023:Coronary Angiography / Q000379:methods; D054059:Coronary Occlusion / Q000000981:diagnostic imaging / Q000209:etiology*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000209:etiology*; D003330:Coronary Vessel Anomalies / Q000150:complications* / Q000000981:diagnostic imaging; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D014188:Transposition of Great Vessels / Q000150:complications / Q000601:surgery*; D016896:Treatment Outcome