Type:
Educational Exhibit
Keywords:
Arteries / Aorta, Cardiac, CT-Angiography, CAD, Education and training
Authors:
M. Betancourt Torres1, L. C. Figueroa-Diaz2, A. Saldana3, J. Maldonado2; 1San Juan/US, 2San Juan, PR/US, 3San Juan, Puerto Rico/US
DOI:
10.26044/ecr2019/C-3422
Background
Coronary Artery Anomalies (CAA) are a rare condition that can be found as an isolated finding or in conjunction with congenital heart disease.
Many of the CAA are considered to be of no clinical significance.
Only 20% of them have been found to be clinically significant,
usually presenting with angina,
myocardial infarction or sudden cardiac death.
CAA is the second most common cause of sudden cardiac death among young athletes,
after hypertrophic cardiomyopathy.
Historically,
conventional angiography was the gold standard for evaluating CAA.
However,
it has been recently demonstrated that Coronary Computed Tomography Angiography (CCTA) improves diagnostic accuracy and has emerged as the standard for diagnosis [7].
Anatomy:
There are two main coronary arteries that arise from the coronary sinuses in the aortic root: the right coronary artery (RCA) arises from the right coronary sinus and the left coronary artery (LCA) arises from the left coronary sinus.
There is a posterior coronary sinus which usually does not give rise to a coronary artery,
hence termed the noncoronary sinus.
The RCA arises inferior to the LCA and courses through the right atrioventricular groove giving off several branches.
The first branch after its origin is the sinus-atrial nodal branch,
which supplies the SA node.
It then gives off the right marginal branch that supplies the right border of the heart.
The RCA then courses to the posterior surface of the heart giving off the atrioventricular nodal branch and,
in most people,
the posterior descending artery (PDA).
The LCA bifurcates into the left anterior descending artery (LAD) and left circumflex artery (LCX).
The LAD courses along the anterior interventricular groove supplying both ventricles and the anterior two thirds of the interventricular septum.
The LCX courses along the left atrioventricular groove giving off obtuse marginal branches that supply the left ventricle.
Anatomical Variants:
Several anatomic variants of the branching pattern of the coronary arteries exist.
The dominance of the coronary circulation is determined by which artery gives rise to the PDA.
The most common pattern is a right dominance pattern,
observed in 85% of the population,
in which the PDA is a branch of the RCA.
The left dominant pattern is seen in 7-8% of population,
and in such cases the PDA arises from the LCX.
The remaining 7% of the population has been described as being co-dominant [2].
Classification Scheme:
CAA can be classified based on the anatomy (anomalies of origin,
course or termination) or by the clinical significance (hemodynamically significant or not hemodynamically significant).
Hemodynamically significant anomalies have been associated with shunting,
ischemia or sudden cardiac death and include: atresia,
origin from the pulmonary artery,
interarterial course and congenital fistula [6].
Not hemodynamically significant anomalies include: duplication,
origin anomalies,
systemic termination,
origin from the aorta in anomalous position,
prepulmonic,
transseptal or retroaortic course,
among others.
The anatomy classification scheme divides them by [2]:
- Anomalies of origin: High origin,
multiple ostia,
single coronary artery,
anomalous origin of coronary artery from pulmonary artery.
- Anomalies of course: Myocardial bridging,
duplication of arteries.
- Anomalies of termination: Coronary artery fistula,
extracardiac termination,
coronary arcade.