Invited Commentary: Notwithstanding the Significance of Anatomy in Anomalous Aortic Origin of a Coronary Artery, Physiology Is Important, Too.

The management strategies for anomalous aortic origin of a coronary artery (AAOCA) are based on anatomy, symptoms, and stress tests for evidence of ischemia. These strategies remain associated with low levels of evidence. Stress tests for ischemia or ventricular dysfunction, the only widely used physiological tests, are not adequately reliable. Additional physiological metrics are needed to build reliable strategies. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are physiological measurements that are used in assessing acquired coronary artery disease (CAD). In this commentary, we describe FFR and iFR and review studies supporting their utility in assessing CAD. We describe a few small studies of their use in assessing AAOCA. Finally, we comment on the unique features of AAOCA that mandate further investigation on how to conduct and interpret FFR/iFR measurements. Even at a point where we understand how to do this, determining the effectiveness of these measurements in improving outcomes and guiding management will require lengthy and challenging trials. A collective effort of institutions that manage AAOCA will be essential.