Coronary Artery Dimensions on Computed Tomography Following the Neonatal Arterial Switch Operation for the Complete Transposition of the Great Arteries

Coronary events are life-threatening long-term complications of the arterial switch operation for complete transposition of the great arteries. The aim of our study was to assess the dimensions of the reimplanted coronary arteries and their relationship with the various geometric characteristics to gain a better understanding of the involved mechanisms. Coronary computed tomography angiography (CCTA) scans of 78 asymptomatic pediatric patients were performed at the age of 10.7 (6.3-17.8) years. The position of the ostia, the branching angles, and the diameters of the coronary arteries were determined in a subgroup of 51 patients presenting the usual preoperative coronary anatomy. Mean Z-score of the left main coronary artery (LMCA), left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and right coronary artery (RCA) diameters were 0.7 +/- 1.2, - 0.4 +/- 1.1, - 0.3 +/- 1.1, and - 0.3 +/- 1.1, respectively. The Z-score of the ostial LMCA diameter had a positive correlation with the remoteness from the main pulmonary artery (p < 0.001) and the branching angle (p = 0.001). The ostial diameter Z-score of the LMCA had a negative correlation with the interval between the arterial switch operation and the CCTA (p = 0.004). Even though most of the coronary diameters fell within the accepted range, which suggests normal overall development, acute branching angle and more anterior origin were associated with smaller ostial coronary artery diameter Z-scores. To prove the clinical relevance of the smaller ostial diameter of high-risk left coronary arteries and the decrease of ostial coronary artery Z-scores over time needs further follow-up studies.