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Clinical case: Long ectopic left main coronary artery

Overview of a clinical case on long ectopic left main coronary artery.

This article is based on a case report published in the Journal "Case Reports in Surgery" in 2015, by Caroline C. Jadlowiec, Beata E. Lobel, Namita Akolkar, Michael D. Bourque, Thomas J. Devers, and David W. McFadden.

It has been modified and reviewed by Joel A. Vilensky PhD, Carlos A. Suárez-Quian PhD, Aykut Üren, MD.

  1. Objectives
  2. Case description
    1. History and physical exam
    2. Paraclinical exams and imaging
  3. Anatomical and procedural considerations
  4. Objective explanations
    1. Objectives
    2. Exertional angina pectoris: Anatomy and physiology
    3. Coronary angiography: Anatomy
    4. Cardiac stress (treadmill) test
    5. Heart dominance
  5. Sources
+ Show all


After reviewing this case you should be able to describe the following:

  • The anatomical/physiological basis of stress (exertional) angina pectoris. How does it differ from a myocardial infarction?
  • The anatomical basis of coronary angiography.
  • What is the clinical value of a cardiac stress (treadmill) exam.
  • The anatomical basis of heart dominance.

Case description

History and physical exam

A 35-year-old diabetic and hypertensive man presented with stress (exertional) angina pectoris. He was 5 feet tall and weighed 115 lbs. His vitals were stable and a cardiovascular system examination found nothing remarkable.

Paraclinical exams and imaging

There were no obvious signs of myocardial ischemia or infarction in the electrocardiogram. His treadmill test was strongly positive for a diagnosis of a stress induced myocardial ischemia.

Figure 1. A superior view of cadaver photograph showing the coronary arteries with the right atrium removed. RCA, right coronary artery; LCA, left coronary artery, and CxA, Circumflex artery.

Echocardiography revealed normal left ventricular systolic function with an ejection fraction of 60% and insignificant mitral valve regurgitation. Coronary angiography was performed through the right radial artery route. During this procedure, the cardiologists probed for the LCA (left coronary artery or LMCA or left main coronary artery) from its typical origin from the ostium in the left aortic sinus but were unable to visualize it (Figure 1-2).

Figure 2. An anterior view of cadaver photographs, the left one is more to the right than the right one. RCA, right coronary artery; LCA, left coronary artery, and CxA, Circumflex artery.

Finally, the LCA was selectively cannulated from the right aortic sinus, and shown to branch into the anterior interventricular artery (or left anterior descending artery or LAD) and the CxA (Circumflex artery) (Figure 3). Thus this patient had a known but rare variant of the origin of his LCA. The angiogram also revealed critical stenoses in the CxA (Figure 3), which were presumably responsible for his angina.

Figure 3. Photograph from angiogram showing the LCA artery, its opening in the right aortic sinus (aberrant) and its branches. The circled regions show areas of the CxA (Circumflex artery) in which plaque has partially occluded blood flow.

The RCA (right coronary artery) was visualized in its normal path and to be dominant in this patient (Figure 4).

Figure 4. Photograph from angiogram showing the RCA, its opening in the right aortic sinus (normal) and its branches.

A CT angiogram was done a few days later to better show the anomalous origin of LCA from the right sinus that was seen on radiographic angiography. Further, a 3D reconstruction of the LCA based on the CT revealed that it travelled superiorly after its origin and then underwent a reverse U-turn, while it was coursing anteriorly over the right ventricular outflow tract (RVOT) before finally giving rise to the anterior interventricular artery and CxA (Figure 5).

Figure 5. 3D reconstruction of the path of the coronary arteries in this patient based on the CT angiogram. RVOT, right ventricular outflow tract.

Anatomical and procedural considerations

The LCA normally arises from the left aortic sinus (sinus of Valsalva) and has a diameter ranging from 3 to 6 mm and a length ranging from 10 to 15 mm. In this patient, the artery’s length was close to 60 mm. The clinical significance of this especially long LCA is that this excessive length has to be considered if any interventional procedures are contemplated for this patient such as balloon angiography and placement of a stent to alleviate the patient’s exertional angina.

Figure 6. Axial CT showing a patient with the most serious form of LCA arising from the right aortic sinus. In this case, the artery traverses the space between the aorta and the pulmonary trunk and is thus subject to compression between these two vessels. AO, aorta; PT pulmonary trunk; RA, right atrium; LA, left atrium. Modified from: Marier AT, Malik JA, Slim AM. Anomalous Left Coronary Artery: Case Series of Different Courses and Literature Review. Case Reports in Vascular Medicine Volume 2013, Article ID 380952, 5 pages.

LCA arising from the right sinus of Valsalva is a rare congenital coronary anomaly. This anomaly is either benign or serious; depending especially on the relation of the anomalous LCA to the aorta and pulmonary artery. Potentially, the most serious anomaly is associated with sudden cardiac death and warrants prophylactic coronary bypass surgery.

This particular patient’s anomalous left coronary artery had a prepulmonic course, anterior to the pulmonary outflow tract. This variant is not associated with sudden cardiac death. However, in some patients, the aberrant LCA originates from the right aortic sinus and then courses between the aorta and the pulmonary trunk (Figure 6). This variant is considered the most serious variant because the pressure in the larger vessels can likely compress the LCA, especially during strenuous exercise. This condition is believed to be responsible for “sudden cardiac death” in some young athletes.

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