Transesophageal Echocardiography of an Anomalous Circumflex Coronary Artery: Anatomy and Implications

A 74-yr-old man was hospitalized after a non-ST elevation myocardial infarction. The patient was scheduled for bypass grafting after angiography revealed complex left anterior descending coronary artery disease with moderate disease in the circumflex (Cx) and right coronary arteries (RCAs). It was noted that the Cx had an anomalous origin which arose from the RCA (Fig. 1).Figure 1.: Coronary angiogram anterior-posterior view showing an anomalous circumflex (ACx) artery arising from the proximal right coronary artery (RCA). The ACx follows a retro-aortic course around the aortic root. RCC = right coronary cusp; LCC = left coronary cusp; NCC = noncoronary cusp.After induction of general anesthesia and invasive line placement, a transesophageal echocardiography (TEE) probe was placed. An unusual finding was seen in the midesophageal long-axis view almost immediately: an apparent communication between the noncoronary sinus of Valsalva and the left atrium (Fig. 2) (Video 1, see Supplemental Digital Content 1, https://links.lww.com/AA/A26, a midesophageal aortic valve long-axis view showing the anomalous circumflex [arrow] as is follows its retro-aortic course; it gives the appearance of a communication between the noncoronary sinus of Valsalva and the left atrium). However, flow between the chambers could not be demonstrated with color Doppler. On further TEE examination, this proved to be the anomalous Cx previously identified. Although its origin could not be identified, its path could be followed through a retro-aortic course to its usual location in the atrioventricular groove (Fig. 3) (Video 2, see Supplemental Digital Content 2, https://links.lww.com/AA/A27, from a midesophageal 4-chamber view [with progressive anteflexion of the probe], the course of the anomalous circumflex is delineated as is travels behind the aorta and into the atrioventricular groove). The rest of the comprehensive examination revealed normal ventricular sizes and functions, mild aortic regurgitation, and a small patent foramen ovale with left to right shunting. No other congenital abnormalities were discovered. After uncomplicated bypass grafting, the TEE revealed no changes from the prebypass examination; specifically, there were no wall motion abnormalities in the Cx territory.Figure 2.: A midesophageal aortic valve long-axis view showing the anomalous circumflex (arrow) as is follows its retro-aortic course. The imaging plane through the anomalous circumflex at this level gives the appearance of a communication between the noncoronary sinus of Valsalva and the left atrium.Figure 3.: A schematic illustration of the superior view of the heart with atria removed shows the course of the coronary arteries. The anomalous circumflex (ACx) arises from the right coronary artery (RCA) and travels posterior to the aorta into the atrioventricular groove. The dotted line indicates the normal bifurcation of the left main coronary artery into the left anterior descending (LAD) and circumflex (Cx). MV = mitral valve; TV = tricuspid valve; PV = pulmonic valve; RCC = right coronary cusp; LCC = left coronary cusp; NCC = noncoronary cusp. (Adapted from Angelini P. Circulation, 2007, 115, 1296–305.)Coronary artery anomalies are a relatively common finding, with an incidence between 1% and 5.64%, depending on the diagnostic criteria.1 Most anomalies are asymptomatic and discovered coincidentally during coronary angiography. Serious coronary artery anomalies involve those which have nonarterial origins, such as the pulmonary artery, or those in which the anomalous course passes between the aorta and the pulmonary trunk. These can present with ischemia, heart failure, or sudden death. Anomalous origin of the Cx from the right sinus of Valsalva or from the proximal RCA is a relatively common coronary artery anomaly with a reported incidence in one series of 1950 consecutive angiograms of approximately 1 in 150.1 The retro-aortic course is generally considered to have a benign prognosis. Although not commonly performed, the evaluation of coronary artery anatomy has a Class IIb indication for intraoperative TEE according the 2003 American College of Cardiology/American Heart Association/American Society of Echocardiography updated guidelines.2Table 1 summarizes the TEE evaluation of normal coronary arteries.3 The role of TEE in the assessment of anomalous coronary arteries is summarized in Table 2. Briefly, the TEE examination should determine their origin, course, and relationship to the great vessels. TEE can also exclude other associated congenital abnormalities. The role of TEE in assessing the coronary anatomy is also important in cases of coronary artery fistulae4 and aneurysms.5Table 1: Transesophageal Assessment of Normal Coronary ArteriesTable 2: Intraoperative Transesophageal Assessment of Coronary Arteries AnomaliesThe presence of an anomalous Cx did not affect this patient’s intraoperative course but it could have posed problems in other cases. If not previously identified, the finding may have caused misinterpretation. In this case, the initial images gave the appearance of a sinus of Valsalva to left atrium fistula or a coronary artery fistula. This was due to the tangential course of the anomalous Cx as it traveled around the aortic root. This could have easily caused confusion and potentially inappropriate therapy if it was not previously identified, and the echocardiographer was not familiar with the potential for anomalous coronary anatomy. Second, surgical access for bypass grafting to the proximal Cx may be challenging or impossible given its retro-aortic course. Third, valve surgery may be complicated by the presence of an anomalous Cx. Several cases of wall motion abnormalities, myocardial infarction, and sudden death have been described in the literature and are thought to be related to mechanical compression of an anomalous retro-aortic Cx by the annuli of mechanical mitral or aortic valves. Given these reports, some have suggested that smaller prostheses or stentless valves should be considered to avoid retro-aortic compression of the Cx.6 When aortic root procedures are undertaken, the presence of an anomalous retro-aortic Cx is important to identify as it may be at risk during dissection or root enlargement. This case presents the relatively common coronary artery anomaly of a Cx artery arising from the RCA. Although usually benign, intraoperative complications from this particular anomaly have been described. Knowledge of coronary artery anomalies along with comprehensive intraoperative TEE will further define and help avoid misinterpretation of this finding.

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