Post-operative Assessment of the Arterial Switch Operation: A Comparison of Magnetic Resonance Imaging and Echocardiography

After an arterial switch operation (ASO), serial imaging is necessary to monitor for maladaptive changes. We compared cardiac magnetic resonance imaging (CMR) to 2-D transthoracic echocardiography (TTE) in assessing post-operative ASO patients. We performed a retrospective review of patients at a single tertiary care center who underwent an ASO and subsequently had a CMR performed from 7/2010 to 7/2016. Those with single ventricle anatomy, congenitally corrected transposition of the great arteries, or previous atrial switch operation were excluded. TTE obtained within 6 months of the CMR was used for comparison. Parameters compared included ventricular size and systolic function, semilunar valve regurgitation, neo-aortic root dimension, and the presence of branch pulmonary artery (PA) stenosis (on CMR by the Nakata index or right/left flow differential; on TTE by peak velocity > 2 m/s or PA diameter Z score