Small Left Coronary Arteries After Arterial Switch Operation for Complete Transposition

Background. Myocardial perfusion is not completely normal and ventricular function is depressed in some patients after the arterial switch operation. The basic mechanism has not yet been defined totally. Methods. The diameters of the right, left main trunk, anterior descending, and circumflex coronary arteries were measured by computer-assisted densitometry at 8 to 86 months (mean, 47.5 months) after the arterial switch operation in 86 patients. Results. The Z scores, compared with control, were +2.0 ± 0.3, −1.8 ± 0.3, and −1.5 ± 0.3 for the right, left anterior descending, and circumflex coronary arteries, respectively. The Z score for the total cross-sectional area of the three vessels was −1.5 ± 0.3. These parameters did not correlate with left ventricular ejection fraction. Conclusions. At the midterm follow-up after the arterial switch operation for complete transposition of the great arteries, the left coronary arteries are small. A careful follow-up study is mandatory to clarify the clinical significance of this finding.