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- Paolo Angelini, MD∗ ()
- ↵∗Department of Cardiology, Texas Heart Institute, 6624 Fannin, Suite 2780, Houston, Texas 77030
I read with interest the comprehensive and diligent review by Lorber et al. (1) regarding congenital coronary anomalies, as studied by echocardiography in the young. The authors’ main conclusion seems to be that echocardiography, when used by highly trained professionals, can identify high-risk coronary artery anomalies and can be used to manage their treatment (indications and techniques) in patients younger than 30 years of age. To better understand such anomalies (2,3), I believe that the following concepts should be collegially discussed.
Terminology is important. The authors seem to use the term anomalous aortic origin of a coronary artery (AAOCA) to designate any case of abnormal origin of a coronary artery from the opposite sinus (ACAOS). My group recently proposed different terms to signify both the involved artery (left vs. right) and the proximal course (intramural [IM] vs. intraseptal [IS] or intraconal) (2,3). For example, left ACAOS-IM versus right ACAOS-IS would, respectively, identify an anomalous left coronary artery with an IM aortic course versus an anomalous right coronary artery with an IS (or intraconal or infundibular) course. Additionally, one must remember that an IM (possibly high-risk) course may be present (with mild to critical ostial stenosis) in the absence of coronary ectopy (2).
Mechanisms and severity of stenosis vary dramatically. Discussions about the functional repercussions of these anomalies should refer to their associated features, especially the proximal course, which indicates the specific mechanism of coronary dysfunction (or lack thereof). As Lorber et al. (1) recognize, the IM course inside the tunica media of the aorta is the most frequent feature (but not the only one) that is potentially associated with ischemia. In and of themselves, neither ectopy, an acute angle, a slitlike orifice, nor an interarterial course can cause stenosis. The common mechanism in ACAOS-IM is hypoplasia (trivial to severe) and/or obligatory lateral compression. The IM course is not a dichotomous factor in terms of indications for surgery (especially in young children), but it implies a continuous spectrum of functional repercussions that require accurate (spatiotemporal) imaging. Echocardiography may adequately identify the ostial location and type of anomalous course (in small patients), but much better precision is needed to clarify systolic and diastolic stenosis and variability of the luminal area at rest and during exercise (2,3).
Primary screening should be followed by severity evaluation. Ideally, evaluation of ACAOS (or AAOCA) would imply the use of an initial accurate screening protocol in appropriate at-risk populations (based on systematic study or symptoms); we recommend magnetic resonance imaging (MRI) (2) for screening adolescents and adults at risk. If selectively indicated (by symptoms, exercise habits, stress tests, computed tomography angiography, strenuous exercise), such screening would be followed by expert evaluation of stenosis, usually by means of intravascular ultrasound (IVUS) in the presence of positive findings (3). This technique has 10 times better precision than angiography and is much more precise than echocardiography (3).
Echocardiography is less reliable in large persons. When echocardiography was used as a primary screening stratagem in thousands of adults (4), the prevalence of ACAOS was 0% to 10% of that observed on MRI. This is a powerful indication that echocardiography is less reliable in large persons (high-school age and upward) than in small children.
The main objection to MRI/IVUS is cost. Screening MRI and subsequent IVUS-based secondary evaluation in selected carriers (2,3) are hindered largely by cost. In expert hands, screening MRI has nearly a 100% ability to clarify the ostial location and proximal course (2). Mainly, IVUS is proposed to indicate intervention in symptomatic adolescents and older patients, specifically before participation in school-sponsored sports. In adults, IVUS has almost 100% success in providing diagnostic images, although the precise cutoff severity of obstruction indicating the need for intervention is unclear for sedentary persons versus athletes, young people versus adults, and so on (2,3).
In conclusion, apparently 0.5% of the general population carries some form of ACAOS; in the United States, this corresponds to 1,650,000 cases (2,3). Therefore, an effective/affordable and selective screening program, with an optimally accurate testing scheme, is urgently needed.
Please note: Dr. Angelini has reported that he has no relationships relevant to the contents of this paper to disclose.
- 2016 American College of Cardiology Foundation
- Lorber R.,
- Srivastava S.,
- Wilder T.J.,
- et al.
- Angelini P.
- Angelini P.,
- Uribe C.,
- Monge J.,
- Tobis J.M.,
- Elayda M.A.,
- Willerson J.T.