Retroaortic coronary course

Last revised by Joachim Feger on 1 Nov 2023

A retroaortic course refers to a coronary artery taking its route posteriorly between the non-coronary sinus and the interatrial septum and is considered a ‘benign anomalous course’.

Clinical conditions associated with a retroaortic course of a coronary artery include 1-4:

Similar to a prepulmonic anomalous coronary artery course, a retroaortic course is thought to not be of increased hemodynamic risk and will be most probably found as an incidental finding on invasive coronary angiography (ICA)cardiac CT or cardiac MRI.

A retroaortic coronary artery course is usually associated with an ectopic origin of either the left main coronary artery or the left circumflex artery from the right coronary sinus or the right coronary artery. It supplies the left coronary or circumflex territory and can be visualized on invasive coronary angiography (ICA) coronary CTA or coronary MR angiography as a major coronary artery coursing posterior to the aortic root, where normally no major coronary arteries are found 1,2.

Several findings on echocardiography have been described, including:

  • retroaortic anomalous coronary (RAC) sign 8,9

  • bleb sign 

    • visualized from the midesophageal aortic valve long-axis view

    • anomalous vessel visualized in the short axis as a hypoechoic "bleb" at the mitral-aortic junction in proximity to the noncoronary cusp 10

    • similar structure described in the parasternal long-axis view on transthoracic echocardiography

    • corresponding short axis views should demonstrate this structure to be tubular to exclude the presence of artifact

The radiology report should include a description of the following features:

A retroaortic course is considered benign and not of hemodynamic importance. Management will entirely depend on symptoms and associated findings. However, it can complicate aortic valve surgery 1.

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