Late coronary insufficiency after arterial switch operation for transposition of the great arteries

Abstract

Background: Arterial switch operation (ASO) is the current treatment of choice for neonates with transposition of the great arteries. Operative morbidity and mortality are currently very low, with favorable early and mid-term clinical results. Long-term studies are still scarce, as most patients are only now reaching late adolescence and adulthood, but suggest that patency and function of the re-implanted coronary arteries may be a concern. Methods and results: Between 1994 and 2011, 103 consecutive patients who underwent neonatal ASO were routinely studied with single-photon emission computed tomography (SPECT) and cardiac catheterization with angiography; we identified two patients who presented with late coronary insufficiency at the age of 16. Both had Yacoub type A native coronary anatomy and an uneventful ASO, with routine SPECT and angiography study at the age of two showing normal post-operative coronary patency and function. One patient complained of chest discomfort with exertion while the other remained asymptomatic, with electrocardiographic baseline ST-T non-specific changes. The prompted investigation showed a positive exercise test for coronary ischemia and SPECT revealed moderate-to-severe anterior and anteroseptal left ventricular wall ischemia; further investigation with cardiac catheterization and multislice computed tomography with 3D reconstruction showed severe kinking at the ostium of the left main coronary artery. In the first patient an internal thoracic artery to coronary artery bypass was performed while in the other, due to the presence of an intramural coronary segment, a proximal coronary patch angioplasty was performed. Both surgeries and post-operative periods were uneventful and at 6-months follow-up both remain asymptomatic. Conclusion: Coronary lesions after ASO have an estimated incidence of 3-7% with most cases reported between the ages of 2 and 5, and have been related to complex native coronary anatomy (Yacoub type B – E). Nevertheless, late coronary insufficiency may develop in patients with Yacoub type A native anatomy in whom good post-operative results had been previously confirmed with functional and invasive anatomic studies and without associated symptoms, rendering routine and lifelong clinical evaluation and exercise or pharmacologic stress testing, with invasive angiography when needed, an essential component of the follow-up of these patients. Further studies are required to fully characterize the incidence of late coronary insufficiency after ASO.