Management of Anomalous Coronary Arteries
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As you know, the SCCT is the only professional medical membership organization dedicated to ensuring patient access to the appropriate use of cardiovascular CT. The SCCT Board of Directors thought that it would be beneficial to our members to create a Case of the Month series showcasing cardiac CTA in various clinical scenarios. this series will be spearheaded by the collective members of the SCCT FiRST committee. Please provide feedback or forward any questions to 




Coronary CTA for the Identification and Management of Anomalous Coronary Arteries

James Lee, MD; Kelley Branch, MD, MS

University of Washington

Division of Cardiology

Seattle, WA


49 year-old with hepatitis B, hepatitis C, alcohol abuse and hypertension presented to an outside facility with atrial fibrillation with rapid ventricular response. Transthoracic echocardiogram revealed a bicuspid aortic valve with fusion of the right and left coronary cusps with a dilated ascending aorta and moderate aortic regurgitation (figure 1a-b). He was seen in cardiology clinic for follow up. He denied any family history of sudden cardiac death, aortic dissection, or connective tissue disorder. Cardiac MRI was ordered due delineate aortic root dimensions, ejection fraction and to quantify degree of aortic regurgitation. This confirmed the bicuspid valve and showed a maximal dimension of 51mm at the aortic sinus (figure 1c-d). Localizer images were suggestive of an anomalous right coronary artery, which prompted a coronary CTA for further evaluation.    


Coronary CTA clearly demonstrated the right coronary artery arising at the superior portion of the left coronary sinuswith an intra-arterial course between the aorta and pulmonary artery (figure 1f-i). Curved multi-planar reconstruction images showed an acute angle takeoff of the right coronary artery and an ostial narrowing with a minimal luminal diameter of 2 mm (figure 1g). Double oblique maximal intensity projection images further delineate the inter-arterial course, which measured approximately 1 cm in length (figure 1h-i). The remaining coronary artery segments were angiographically free from stenosis. On follow up visit, the patient noted the interval development of non-specific chest discomfort and dizziness with exertion. An exercise nuclear stress test was performed which showed a small to moderate sized region of mild myocardial ischemia involving the inferior wall of the left ventricle (figure 1j).   


Figure 1 



Coronary artery anomalies encompass a diverse group of rare coronary artery variations. A retrospective series of 2096 patient undergoing coronary CTA shows a prevalence of approximately 2% (Cengiz et al 2011). However not all coronary artery anomalies are felt increase the risk of sudden cardiac death. Historically high-risk findings of coronary artery anomalies include acute angle takeoff relative to the aorta, slit-like coronary artery ostium, initial aortic intramural course, and an "intra-arterial course" between the aorta and pulmonary trunk, primarily involving the left coronary artery. A registry of 6.3 million recruits undergoing initial military training showed 126 non-traumatic deaths. On autopsy, 21 of these recruits had a coronary artery anomaly, all of which were the variant of the left coronary artery originating from the right coronary sinus with an inter-arterial course between the aorta and the pulmonary artery (Eckart et al 2004). There are several proposed mechanisms of sudden cardiac death in these patients with an inter-arterial course. One proposed mechanism is coronary compression between the aorta and the pulmonary artery during extreme exertion causing myocardial ischemia. Another mechanism is transient occlusion of the coronary ostium due to the acute takeoff angle of the proximal coronary artery. Finally, coronary hypoplasia at the ostium of the anomalous coronary artery may also play a role in ischemia. While the mechanisms seem plausible, the true significance of these coronary findings is not clear (Taylor et al 1997).


The more interesting diagnostic dilemma in our patient is the potential for the dilating aortic root to cause myocardial ischemia. The increasing aortic aneurysm could theoretically increase the lateral compression on the right coronary artery thereby decreasing right coronary artery blood flow. Dynamic compression of the coronary arteries by dilation of the great vessels has been reported (Chaikriangkrai et al. 2013). Although our patient has the lower risk variant of right coronary artery from the left cusp with intra-arterial course, the presence of inferior ischemia raises the question of whether surgical intervention should be expedited. Typically when found in isolation, this is performed by unroofing of the proximal right coronary artery.  The 2014 ACC/AHA guidelines on valvular heart disease provide a Class I level of evidence recommendation to operatively repair the aortic sinuses or replace the ascending aorta in patients with a bicuspid aortic valve when the maximal ascending aortic diameter is greater than 5.5 cm. In bicuspid aortic valve patients who are undergoing valve replacement because of severe aortic stenosis or regurgitation, the guidelines recommend ascending aorta replacement when the ascending aorta is greater than 4.5 cm. As our patient has an aortic root diameter of 5.1 cm and only moderate aortic regurgitation, he does not meet guideline criteria for surgery. Additionally, in a relatively young patient, it is unclear of whether he will have better durable result with valve sparing surgery with a bypass graft to the right coronary artery compared to a Bentall Procedure with aortic valve and root replacement with coronary artery unroofing and re-implantation. Given the lack of guiding data, the management plans remains in multi-disciplinary discussions and a final decision regarding surgery is pending.

Angelini et al. "Congenital Heart Disease for the Adult Cardiologist Coronary Artery Anomalies An Entity in Search of an Identity." Circulation. 2007; 115: 1296-1305. doi: 10.1161/CIRCULATIONAHA.106.618082.  


Cengiz et al. "Coronary Artery Anomalies: The Prevalence of Origination, Course, and Termination Anomalies of Coronary Arteries Detected by 64-Detector Computed Tomography Coronary Angiography." Journal of Computer Assisted Tomography: September/October 2011 - Volume 35 - Issue 5 - pp 618-624. doi: 10.1097/RCT.0b013e31822aef59


Chaikriangkrai et al. "Stenting of a left main coronary artery compressed by a dilated main pulmonary artery." Catheterization and Cardiovascular Interventions. Volume 82, Issue 5, pages E684-E687, 1 November 2013. DOI: 10.1002/ccd.25093.


Eckart et al. "Sudden Death in Young Adults: A 25-Year Review of Autopsies in Military Recruits." Ann Intern Med. 2004;141(11):829-834. doi: 10.7326/0003-4819-141-11-200412070-00005.


Taylor et al. "Anomalous right or left coronary artery from the contralateral coronary sinus: "High-risk" abnormalities in the initial coronary artery course and heterogeneous clinical outcomes." American Heart Journal. Volume 133, Issue 4, April 1997, Pages 428-435.


Taylor et al. "ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography." J Am Coll Cardiol. 2010;56(22):1864-1894. doi:10.1016/j.jacc.2010.07.005.



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