Retroaortic coronary course

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’.

Epidemiology

Associations

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

• other congenital coronary artery anomalies

  • ectopic origin of the left main coronary artery

  • ectopic origin of the circumflex artery

  • single coronary artery

• other forms of congenital heart disease

Clinical presentation

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.

Radiographic features

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.

Echocardiography

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

Radiology report

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

• right coronary artery origin, course, segments

• circumflex artery with course, branches, and segments

• left main coronary artery origin and variant anatomy

• left anterior descending artery with course branches and segments

• coronary artery disease and stenoses with location based on the AHA coronary artery segment model

Treatment and prognosis

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.