Interarterial course of the right coronary artery

Dr Daniel J Bell and Dr Craig Hacking et al.

Interarterial course of the right coronary artery, may occur if the right coronary artery (RCA) has an aberrant origin from the the left coronary sinus. The interarterial course occurs because the artery passes between the ascending aorta and the pulmonary trunk.

It is an uncommon anatomic variant with a potential risk of cardiac ischemia, hence its alternative monicker, malignant course of the right coronary artery.

When the right coronary artery arises aberrantly in this manner, there are three possible courses it may take:

  • interarterial with intramural segments: highest risk
  • interarterial and extramural
  • interatrial

Some think that this anomaly carries an increased risk of cardiac ischemia, myocardial infarction, and possibly sudden death. Others consider the aberrant course of the right coronary artery to be less concerning than an aberrant course of the left coronary artery. Repair strategies vary depending on the institution's level of concern.

The cause of ischemia from this anomaly is not completely understood. Classically, extrinsic compression of the coronary artery between the aortic root and the right ventricular outflow tract was considered to be the primary problem, but there is increasing evidence that the risk may be mostly due to the anomalous coronary artery's flow-limiting 'slit'-like orifice.

The highest risk situation is considered to be the interarterial course with segments that course through the wall of the aorta.

Congenital coronary artery anomalies
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Article information

rID: 36573
System: Vascular, Cardiac
Section: Anatomy
Synonyms or Alternate Spellings:
  • Inter-arterial course of the RCA
  • Inter-arterial course of right coronary artery
  • Malignant variant inter-arterial course of right coronary artery

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Cases and figures

  • Case 1: malignant inter-arterial course of RCA
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  • Case 2: inter-arterial course of RCA
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  • Case 3
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  • Case 4: Anomalous right coronary artery (ARCA) with interarterial course
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