Introduction
Numerous studies have assessed the complexity and variability in origin and course of the coronary arteries when discordant ventriculo-arterial connections are found in the setting of concordant atrioventricular, the arrangement usually described as transposition.1-12Prior to the introduction of the arterial switch procedure, such variability was mainly of academic interest. Knowledge of the variability is now of paramount surgical importance, with certain variations presaging a poor outcome.8,12-14Understanding of the variations, and their significance, has been complicated thus far by lack of uniform descriptions. Classifications have tended either to be incomplete,8 or excessively complex.4 The Leiden approach is most universally applicable.8,9 The system does not, however, account for all the potentially significant variables, such as looping.12 The course of the artery to the sinus node may also be of significance.3,15 Among the multiple patterns, the presence of a solitary artery, the intramural variant, and looping, have been associated with an increased risk of complications in some surgical series, but not all.1-28 With this in mind, we have evaluated the varied patterns relative to the early and late outcomes of the arterial switch procedure.