Introduction
Transseptal coronary artery | Interarterial coronary artery | Interarterial coronary artery with an initial intramural segment | |
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Associations | It can only be seen in conjunction with the anomalous origin of the LMCA or LAD from the right coronary sinus or as a branch of the single coronary artery from the right sinus | It can be seen in conjunction with the anomalous origin of RCA, LMCA, or LAD from the opposite sinus or a branch of the single coronary artery from the opposite sinus | It can be in conjunction with anomalous aortic origin of RCA, LMCA, or LAD but not as a single coronary artery branch |
Aortic origin | It has a right-angled or less acute angle of aortic origin and does not appear to abut the aorta after its origin | It has a less acute angle of aortic origin (> 45 degrees) and does not appear to abut the aorta after its origin | It has a hyperacute angle of aortic origin (< 45 degrees), with its course abutting the aorta until it exits the intramural segment |
Ostium | The ostium is round | The ostium is round | The ostium is slitlike |
Origin- relative to the pulmonary annulus | Its origin is below the level of the pulmonary annulus | Its origin is above the level of the pulmonary annulus | Its origin is above the level of the pulmonary annulus |
Proximal course | After the anomalous origin, the initial (extraconal) segment courses between the aorta and RVOT | After the anomalous origin, the coronary artery courses between the aorta and pulmonary artery | After the anomalous origin, in addition to the interarterial course, the coronary artery courses within the aortic wall |
Proximal course- luminal shape | The initial segment (extraconal segment) maintains a round caliber (assessed on the sagittal plane) | The interarterial segment may or may not have an elliptical luminal caliber (assessed on the sagittal plane) | The initial segment (intramural) always shows elliptical luminal caliber (assessed on sagittal plane) |
Subsequent course | After the extraconal course, the transeptal segment dips below the aortic and pulmonary annulus levels into the conal septal myocardium | After completing the interarterial course, the coronary artery may extend below the pulmonary annulus before extending laterally in the atrioventricular groove. It does not dip down onto the septal myocardium below the level of the aortic annulus | After completing the interarterial intramural course, the coronary artery may extend below the pulmonary annulus before extending laterally in the atrioventricular groove. It does not dip down onto the septal myocardium below the level of the aortic annulus |