Preclinical Coronary Artery Anomalies and Silent Myocardial Ischemia in Children: How Can We Identify the Potentially Life-Threatening Conditions?

Abnormalities of coronary artery, congenital or acquired, are rare in the pediatric population, but they frequently present unexpectedly. They may result in life-threatening conditions if unrecognized; however, in infants and children, preclinical coronary abnormalities usually do not present with the typical clinical manifestations seen in adults with myocardial ischemia. Timely diagnosis of silent myocardial ischemia is frequently challenging in children. Myocardial infarction may occur in anomalous left coronary artery from pulmonary artery (ALCAPA), right ventricle-dependent coronary artery seen in pulmonary atresia with intact ventricular septum (PA/IVS), and coronary aneurysm complicated in Kawasaki disease. On the other hand, some coronary artery abnormalities tend to present with unexpected ventricular arrhythmia or sudden cardiac death (SCD). These include aberrant aortic origin of coronary artery (AAOCA) and acquired coronary stenosis after arterial switch operation (ASO) for transposition of the great arteries (TGA), and post-transplant cardiac allograft vasculopathy (CAV), in which affected patients develop cardiac arrest or SCD without anginal pain or before having myocardial infarction. The pathological outcomes of myocardial ischemia in children are significantly different from those in adults with an atherosclerotic coronary disease; thus, the early recognition and detection of preclinical coronary anomalies and silent myocardial ischemia are essential. The underlying mechanism that determines myocardial responses to tissue ischemia involves complex processes, but it is plausible that mitochondrial signaling plays a critical role in determining these pathological paths. The involvement of the autonomic nervous system and the degree of collateral vessel development are contributing factors. In this review, pathobiology of myocardial ischemia and subsequent events will be discussed. The current paradigm of “myocardial ischemia” needs to be revisited in the field of pediatric cardiology.