Anomalous aortic origin of coronary artery

Anomalous aortic origin of coronary artery (AAOCA) refers to a congenital coronary artery anomaly in which a coronary arteries arises from a different coronary sinus.

Terminology

Anomalous origin of the coronary artery arising from the opposite sinus (ACOAS) is a narrower definition and refers to either rightleft coronary artery arising from leftright coronary sinus or vice versa.

Epidemiology

Anomalous aortic origin of the right coronary artery is more common than a left coronary artery arising from the right coronary cusp, but the latter is more dangerous ^1,2. Prevalence of an anomalous aortic origin of the left coronary artery has been estimated up to 0.15% and it is a cause of sudden cardiac death especially in patients < 35 years of age ^1-4.

Associations

Anomalous aortic origin of a coronary artery has been associated with the following conditions ^1,3:

• anomalous course of coronary arteries
• other congenital coronary artery anomalies
• other congenital heart diseases

Clinical presentation

An anomalous aortic origin of the coronary artery can present with angina, palpitations, dyspnoea dizziness, syncope or might be found incidentally, on invasive coronary angiography (ICA),  coronary CTA or coronary MRA. In particular, an anomalous aortic origin of the left coronary artery left arising from the right coronary are more commonly associated with cardiovascular symptoms and might present with sudden cardiac death usually closely associated to exercise ^1-5.

Complications

The most dangerous and rightly feared complication of an anomalous aortic origin of a coronary artery is sudden cardiac death. Other complications include ^1,3-5:

• myocardial ischaemia
• myocardial fibrosis
• ventricular arrhythmias

Pathology

Subtypes

Anomalous aortic origin of a coronary artery can be subdivided according to the origin and the affected coronary artery and its course:

• anomalous coronary artery
  • left main coronary artery arising from the right coronary sinus
  • left anterior descending artery arising from the right coronary sinus
  • circumflex artery arising from the right coronary sinus
  • right coronary artery arising from the left coronary sinus
  • left or right coronary artery arising from the non-coronary sinus
• origin
  • separate ostia (remote, adjacent)
  • single ostium (bifurcation within/outside aortic wall)​​
• course
  • intramural/interarterial
  • prepulmonic
  • subpulmonary/transseptal
  • retroaortic
  • retrocardiac
  • wrapping around the apex

Radiographic features

An evaluation of the proximal course and the relationship to the aortopulmonary root-anatomy of an anomalous aortic origin of a coronary artery is recommended and can be done with coronary MRA,  invasive coronary angiography (ICA) or preferably by coronary CTA ^1-5.

Stress-testing methods seem do not seem to significantly correlate with the prognosis and clinical symptoms in the case of an anomalous aortic origin of the left coronary artery ^1,3 and are not helpful on vasodilator stress ³. Nevertheless, imaging evaluation of physically stress-induced myocardial ischaemia has been recommended for clinical decision making ².

Coronary angiography

Invasive coronary angiography (ICA) may particularly aid if coronary stenosis is suspected or intravascular ultrasound (IVUS) or a flow quantification is needed ¹.

CT

Coronary CTA is the preferential method for visualization and description of origin and course of coronary arteries as well as the relationship of the anomalous vessel to the other cardiac structures.

MRI

Coronary MRA can be alternatively used for the depiction of origin and proximal course and its relationship to the aortic root and the main pulmonary artery ¹ and has been proposed for screening athletes and military recruits due to the lack of radiation exposure ³. It can be conducted with respiratory-gated 3D-imaging (e.g. native 3D-SSFP wholeheart and/or 3D-mDixon after gadolinium contrast).

In addition, this might be combined with perfusion imaging and myocardial viability protocol ¹.

Vasodilator stress-testing (e.g. with adenosine) does not provoke myocardial ischaemia in this situation.

Nuclear medicine

A nuclear stress test might be performed for the assessment of myocardial ischaemia ¹.

Radiology report

The radiological report should include a description of the following features ^1-6:

• ostium and origin the anomalous coronary artery
  • slit-like, fish-mouth-shaped orifice
  • acute angle takeoff
• the course of the anomalous coronary artery
  • intramural/interarterial (long/short intramural segment)
  • transseptal/subpulmonary
  • prepulmonic
  • retroaortic
• other associated coronary artery anomalies (e.g. coronary hypoplasia, coronary atresia)
• coronary artery disease and stenoses
• any associated congenital heart disease

MRI

In addition to the above features:

• regional wall-motion abnormalities
• signs of myocardial fibrosis/myocardial scar tissue

Treatment and prognosis

Patient management is still somewhat controversial and depends on symptoms, the affected coronary artery and the anomalous course. Prepulmonic and retroaortic courses are considered as benign and not of haemodynamic relevance.  An interarterial and especially an intramural course is considered malignant and is associated with an increased risk of sudden cardiac death ^1-3,6.

Recommendations have been given by the American Heart Association (AHA) and the American College of Cardiology (ACC) and the European Society of Cardiology (ESC) in which surgery has been recommended in the setting of myocardial ischaemia attributable to an anomalous aortic origin of either left or right coronary artery (AAOCA) ^1,2.

Surgery has been felt as reasonable in asymptomatic patients in the setting of an anomalous aortic origin of the left coronary artery from the right coronary sinus or in case of ventricular arrhythmias in any type of anomalous aortic origin of coronary artery ¹.

Surgery is not recommended in asymptomatic patients with an anomalous aortic origin of the right coronary artery and no signs of myocardial ischaemia ².

See also

• anomalous course of coronary arteries