Three-dimensional geometry of coronary arteries after arterial switch operation for transposition of the great arteries and late coronary events

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.

Outcomes of coronary artery obstructions after the arterial switch operation for transposition of the great arteries

OBJECTIVE

Coronary obstruction is a rare but common complication of the arterial switch operation for transposition of the great arteries. The majority of patients remain asymptomatic and no risk factors allow targeting for reinforced surveillance. We aim to review the natural history of patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries and occurrence of coronary-related outcomes.

METHODS

We retrospectively reviewed medical records of the 102 patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries in our institution from 1981 to 2022. Outcomes were anti-ischemic treatment introduction, revascularization (surgical or percutaneous angioplasty), and death; investigations that motivated revascularization were also reviewed.

RESULTS

Twenty-eight out of 102 patients presented with myocardial ischemia during the immediate postoperative phase, 31 were diagnosed when symptomatic, and 43 were identified at the presymptomatic stage, according to our screening policy in preschool-aged children. Stenosis-related event occurrence was, respectively, 29 out of 31 and 32 out of 43 in the latter 2 subgroups. Coronary-related mortality reached 10% in patients diagnosed when symptomatic; no patients died in the presymptomatic subgroup. Of the 28 low-risk patients with no signs of ischemia at diagnosis, 10 developed obstruction warranting reintervention during follow-up. Revascularization was motivated by appearance of symptoms in patients with severe stenosis in normal coronary dispositions, and by clinical symptoms or documented silent ischemia in abnormal coronary patterns.

CONCLUSIONS

Occurrence of stenosis-related events remains significant in patients after arterial switch operation, underlining the importance of early diagnosis for timely intervention. Initial anatomical evaluation identifies stenotic and at-risk patients; this will require periodical function testing. Follow-up modalities can be tailored to a patient's individual anatomic characteristics.