FIGURES 11.1 and
11.2 provide an overview of the relationship between the coronary tree, the great vessels, and cardiac chambers. Taking into account these relationships and a “normal anatomy,” the group of coronary anomalies of origination and course can therefore include multiple categories with different clinical significance (
Table 11.1). For example, while an absent left main trunk with split origination of the left coronary artery or an anomalous location of the coronary and ostium within the aortic root or near the proper aortic sinus of Valsalva are anomalies which are rarely associated with adverse outcomes or symptoms, it is currently agreed that the anomalous origin of the coronary artery from the opposite sinus of Valsalva (anomalous coronary artery from the opposite sinus—ACAOS) with interarterial course (
FIGURES 11.3 and
11.4),
17,
18 and in particular the variant with “intramural” course in which the coronary artery course is through the media of the aorta (ACAOS/IAC) (
FIGURE 11.5)
27,
28 are variants of coronary anomalies that can be associated with ischemia and an increased risk of sudden death in young people.
17,
20,
21,
26 A recent study evaluating the use of MRI screening in a general population of adolescents has shown a prevalence of high-risk ACAOS as high as 0.44% (0.11% L-ACAOS-IAC and 0.32% R-ACAOS).
29 The identification of coronary anomalies and delineation of their course with standard coronary angiography can be challenging. As shown in
Table 11.4, characteristics than can help in differentiating between the intramural course and the more benign intraseptal course of a left ACAOS include the course in right anterior oblique (RAO) projection, the type of first branch
from the left main, the presence or absence of left main systolic narrowing, and the location of the distal left main (
FIGURES 11.6, 11.7, 11.8, 11.9, 11.10 and 11.11).
30 In addition, to assessing these characteristics, in the past the challenge of appropriately identifying the course of ACAOS used to be approached by performing coronary angiography in multiple projections with catheters inserted in the left ventricle, right ventricle, the pulmonary artery, and the ascending aorta to facilitate the evaluation of the relationship between the anomalous course of the coronary artery, the cardiac chambers, and the great vessels. The introduction of CT angiography and cardiac magnetic resonance imaging (MRI) has provided new modalities for the proper evaluation of anomalous course and is today part of the standard of care (
FIGURES 11.12, 11.13, 11.14 and 11.15).
5,
31 In addition, the use of intravascular ultrasound imaging and of optical coherence tomography has provided new insights regarding the pathophysiology of ACAOS and the potential mechanism behind the development of ischemia and sudden death.
5 These imaging modalities and additional imaging obtained during surgery (
FIGURES 11.16, 11.17, 11.18 and 11.19) have shown that the potential mechanisms leading to the
development of ischemia can include compression during the cardiac cycle (
FIGURES 11.19 and
11.20), compression of the intramural segment of the artery, coronary spasm,
27 and/or an anomalous takeoff of the vessel leading to a slitlike origin of the native coronary artery (
FIGURES 11.15,
11.21, and
11.22). Thus, it has been recently advocated to include intravascular ultrasound imaging or optical coherence tomography in the evaluation of ACAOS.
27 FIGURES 11.23, 11.24, 11.25 and 11.26 illustrate additional variants of ACAOS, including the benign and common form of left circumflex ACAOS (
FIGURE 11.26), whereas
FIGURES 11.27, 11.28 and 11.29 illustrate 2 unusual cases of anomalous left coronary artery from the pulmonary artery (ALCAPA) with symptoms presenting in late adulthood.
