Influence of coronary anatomy and reimplantation on the long-term outcome of the arterial switch

Background: Abnormal coronary artery anatomy is reported to have a signific ant influence on the outcome of the arterial switch operation. This study e xamines the impact of coronary anatomy and the occurrence of late coronary obstruction on left ventricular (LV) function and long-term outcome. Method s: Coronary artery anatomy, of 170 patients after arterial switch operation (1977-1999), was determined based on operative reports and pre-operative a ortograms. Current status was evaluated using ECGs, echocardiograms, scinti graphy, and post-operative coronary angiograms. Results: In 133/170 patient s, coronary artery anatomy consisted of an anterior descending (LAD) and ci rcumflex artery (Cx) from the left sinus and the right coronary artery (RCA ) from the right or posterior sinus. The left coronary had an intramural in itial course in two of these patients. Fifteen patients had the LAD from th e left and Cx and RCA from the right sinus; eight had LAD and RCA from one sinus and Cx from the other; four had single ostium; and three had three se parate ostia. Four patients had complex patterns and four patients had a su pra commissural coronary. To date, follow-up angiography was performed in 5 9 patients. Surgical coronary sequellae were found in five patients. Two pa tients had an occluded left ostium. Initially, they were asymptomatic but s howed polymorphic ventricular extrasystoles on ECG and moderate LV dysfunct ion with large irreversible perfusion defects on scintigraphy. Both patient s developed ventricular fibrillation at the age of 14 years. One patient di d not survive. The other patient required implantation of a defibrillator. One patient has an occluded RCA, one patient has stenosis of the right osti um and one patient has multiple tortuous collaterals without obstruction of a major branch. In the latter three patients, coronary sequellae were not suspected on EGG, echo, or scintigraphy and were only found on follow-up an giography. Retrograde collateral flow was noted in all three occluded coron aries. LV dysfunction, with normal coronaries, was noted in three patients. All, of these patients, had peri-operative ischaemia suggesting failure of myocardial protection. Two are now asymptomatic with mild LV dysfunction. One patient continues to have severe myocardial dysfunction and secondary a ortic insufficiency. A Ross-like procedure was performed placing the origin al aortic valve in the neo-aortic root. Coronary artery anatomy did not inf luence early survival or late coronary sequellae. Conclusion: Abnormal coro nary anatomy was not a determinant of outcome in our study. Surgical corona ry obstruction is independent of original anatomy. It can be almost silent and is potentially fatal. Follow-up angiography must be considered in all p atients after the arterial switch operation. (C) 2000 Elsevier Science B.V. All rights reserved.