Journal of Cardiovascular Computed Tomography
Pictorial EssaySingle coronary artery: Spectrum of imaging findings with multidetector CT
Introduction
Single coronary artery (SCA) is a rare congenital anomaly in which only 1 coronary artery arises from the aorta and provides blood supply to the entire heart.1 It is classified as an anomaly of the origin of the coronary artery, with a prevalence of 0.024% to 0.066% in the general population.2, 3, 4 It is most commonly found as an isolated finding (60%), but it has also been associated with other congenital heart disorders (40%) with a higher mortality.5, 6, 7, 8, 9
We give a brief summary of the normal anatomy.10 There are 4 coronary arteries, the right coronary artery, left main coronary artery, left anterior descending (LAD) artery, and left circumflex (LCx) artery. The right coronary artery arises from the anterior right coronary sinus. It passes to the right and posterior to the pulmonary artery and then trajects downward into the right atrioventricular groove toward the posterior interventricular septum. The left main coronary artery arises from the left posterior coronary sinus and passes to the left and posterior to the pulmonary artery trunk and then bifurcates into the LAD and LCx arteries which course within the anterior interventricular and left atrioventricular grooves, respectively.
SCA is one of many anomalies of the origin of the coronary arteries, which encompasses high takeoff, multiple ostia, origin from a pulmonary artery branch (either right or left), and origin from opposite or noncoronary sinus (ie, right artery arising from left or noncoronary sinus, or vice versa). In addition, a complete characterization of these anomalies requires a detailed description of the course of the anomalous vessel, such as interarterial (in between the aorta and pulmonary artery), retroaortic, prepulmonic, or subpulmonic/septal.10
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Clinical presentation and diagnosis
In the absence of other cardiac abnormalities, SCA may be entirely asymptomatic.5 However, its recognition is important because some variants may compromise myocardial blood flow. Particularly, patients with an interarterial course of the SCA in whom there may be a “kinking” of the coronary at its origin because of increased angulation caused by the distention of the aorta during exercise which has been advocated as the underlying pathogenic mechanism.3 Moreover, in patients with coronary
Classification
Several classifications have been suggested with the one proposed by Lipton et al1 being the most commonly accepted.1, 2, 5 This classification, which is a modification of the classification proposed by Sharbaugh and White,5 divides SCA into 3 groups according to the location of the ostium, the anatomical distribution, and the course of its branches (Fig. 1).
Prognosis
Although prognosis of persons with SCA is unclear, major adverse cardiac events occur in 15% before the age of 40 years.5 Despite an acute takeoff angle typically not observed in patients with SCA, as seen in other abnormalities, risk of sudden cardiac death is increased, likely because of high coronary flow, which may predispose to early atherosclerotic disease through endothelial injury.12 Currently, no treatment guidelines or follow-up recommendations exist. Revascularization is recommended
Conclusions
SCA is a rare anomaly that may present as an isolated defect or in association with other congenital cardiac malformations. It encompasses a wide variety of presentations, depending on the origin, branching pattern, and course. Its diagnosis is important because of the potential therapeutic implications, although it is usually an incidental finding. As with many other coronary anomalies, its identification is more frequent now because of the increasing use of multidetector CT.
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Conflict of interest: The authors report no conflict of interest.