Compiled By: Resham Mendi, M.D.
History: 55-year-old male with hypercholesterolemia.
Diagnosis:
Anomalous Origin of the Right Coronary Artery
Findings:
(Fig 1-2) Axial post-contrast CT images. The right coronary artery originates from the left coronary sinus, at approximately the 3:30 position, and takes and interarterial course between the aorta and pulmonary artery to reach the right side of the heart. The left coronary artery has a normal origin. (Fig 3) Reformatted axial oblique post-contrast image. Normal proximal RCA anatomy is well-seen in this image, showing the conus (long arrow) and SA nodal (short arrows) branches.
Discussion:
Congenital anomalies of the coronary arteries are not very common, seen in less than 1% of healthy individuals, but can be a cause of sudden death. These anomalies are often seen incidentally, or as a cause of symptoms, on coronary CT angiograms (CCTA) and should be recognized. In fact, some have found CCTA to be superior to conventional angiography in the detection of these anomalies.
The anomalies can be divided into those involving the origin, course, and termination of the coronary arteries.
Anomalies of origin include:
- High takeoff of the coronary arteries
- Usually asymptomatic, but can cause difficulty in cannulating for angiographers
- Multiple ostia
- Separate origins for RCA and conus branch, or for LAD and LCX
- Single ostium for RCA and LCA
- Extremely rare
- Can cause sudden death
- Origin of the coronary artery from the pulmonary artery
- Causes ischemia due to a steal phenomenon
- Origin from the opposite sinus or noncoronary sinus
- 3 types
- RCA from left coronary sinus
- LCA, LAD, or LCX from right coronary sinus
- RCA or LCA from noncoronary sinus
- 4 possible courses
- interarterial (between aorta and pulmonary artery)—can cause sudden death
- retroaortic
- prepulmonic
- septal (subpulmonic)
