Inter-arterial course of the left coronary artery

Dr Vincent Tatco and Dr Amir Rezaee et al.

The inter-arterial course of the left coronary artery, also known as malignant course of the left coronary artery, is defined as origin of the left main or left anterior descending coronary artery from the right coronary sinus of Valsalva with a course between the ascending aorta and the pulmonary artery. This is called a malignant variant because of the marked increased risk for myocardial ischemia or sudden cardiac death.

The incidence of inter-arterial course of the left coronary artery is estimated at ~1.3% of coronary anomalies, and is feared most because of association with myocardial ischaemia and sudden death in young people.

In many cases of inter-arterial course of the left coronary artery, other associated anomalies such as slitlike orifice, stenotic ostium, a sharp, acute angle of takeoff, and an intramural aortic segment are also present.

Different theories has been postulated as a cause of sudden death in these patients: 

  • most accepted theory is higher incidence of occlusion of the ostium secondary to more slitlike orifice
  • occlusion during physical activity due to compression between the major arteries 

Intramural segment within the aortic wall (not to be confused with myocardial bridging) further increase the risk of sudden death.

Because the exact association between inter-arterial course of the left coronary artery and sudden death is still under debate and not well established, surgical repair is mostly depends on other factors such as presence of symptoms and whether other causes could not be found in a patient with a chest pain.  Corrective surgery (if intramural portion exists) is performed by "unroofing" the intramural portion of the anomalous coronary artery resulting in larger orifice.


Congenital coronary artery anomalies
Share article

Article Information

rID: 39470
Systems: Cardiac, Vascular
Sections: Anatomy, Pathology
Synonyms or Alternate Spellings:
  • Inter-arterial course of the left coronary artery
  • Malignant course of the left coronary artery

Support Radiopaedia and see fewer ads

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.