We read with interest the article by Patel et al titled “Echocardiographic Diagnosis, Surgical Treatment, and Outcomes of Anomalous Left Coronary Artery from the Pulmonary Artery.” We congratulate the authors, who brilliantly highlighted the need for a careful and systematic diagnostic approach in children with anomalous left coronary artery origin from the pulmonary artery (ALCAPA), providing additional pediatric experience to the ongoing discussion of the best imaging modality in such patients.

In their report, Patel et al stated that the echocardiographic findings were highly suggestive for ALCAPA in 85% of cases, including retrograde flow within the left coronary artery (CA) (in 91% of cases), color Doppler findings of collateral coronary vessels (in 85% of cases), right CA dilatation (in 81% of cases), abnormal blood flow within the CAs (in 79% of cases), mitral regurgitation (in 74% of cases), left ventricular dysfunction (in 66% of cases), and endocardial fibroelastosis (in 57% of cases). However, the origins of the CAs were clearly visualized in only 54% of cases overall; coronary origins were seen clearly in 31% of the patients imaged between 1990 and 2000 and in 74% of those imaged after 2000. Because imaging of CA origins was imperfect, this diminishes enthusiasm regarding the accuracy of echocardiography in diagnosing CA anomalies in children. Indeed, CA imaging remains a great challenge for sonographers, despite advances in techniques and medical knowledge. In fact, Benavidez et al , reviewing 50,660 echocardiograms from 2004 to 2007 at Boston Children’s Hospital, showed that 16% of echocardiographic misdiagnoses (in total 87 cases) were CA anomalies. In addition, other studies have produced contrasting results in terms of the diagnostic accuracy of echocardiography in CA anomalies in the setting of transposition of the great arteries, as low as 81% to 86%.

Whether physicians should rely on echocardiography alone when ALCAPA is suspected or instead should proceed to further imaging modalities is a subject of ongoing debate. Whether to refer a patient for computed tomography, magnetic resonance imaging, or contrast angiography is an additional source of debate. In any event, the issue of false-negative results on echocardiography and the potential catastrophic consequences of missing the diagnosis are key concerns.

In the study of Patel et al , about half of the patients (19 of 37) underwent surgery on the basis of only echocardiographic findings, while the remaining patients underwent further imaging examinations (angiography in 17 and magnetic resonance imaging in one). More important, after 2005, all patients were successfully imaged using only echocardiography.

Most recent literature supports the accuracy of echocardiography, but interestingly, the diagnosis was further confirmed by angiography and/or computed tomography. In a recent study, Li et al showed that in 22 patients with ALCAPA, the diagnostic accuracy of echocardiography was 90.9%, while accuracy of coronary angiography (17 patients) and coronary computed tomographic angiography (nine patients) increased to 100%. It is true that, unlike other forms of CA anomalies (i.e., transposition of the great arteries), diagnosis of ALCAPA by echocardiography may also be suggested by functional signs, even when the coronary origin cannot correctly visualized. However, there are a few reports of cases in which ALCAPA was misdiagnosed as cardiomyopathy when children were examined using only echocardiography, resulting in life-threatening clinical consequences. Of interest, a false-negative finding of ALCAPA (incidentally discovered during operation for mitral insufficiency) was described also by Patel et al

In summary, we consider that at present, the diagnosis of CA anomalies in children can be reliably made only with echocardiography and that ALCAPA represents a “favorable” anomaly because of its peculiar clinical presentation and associated echocardiographic and electrocardiographic findings (i.e., ischemic lesions). However, relying on echocardiography alone to rule out ALCAPA is not justified in uncertain cases, because other imaging modalities offer higher diagnostic accuracy in CA visualization and may reduce the false-negative rate of echocardiography. In this setting, computed tomography should be preferred, as it is less invasive, highly accurate, and cost effective in coronary imaging.