**1. Introduction**

Coronary arteries (CAs) are the blood vessels that supply the heart muscle with blood.

Intact coronary circulation is therefore important for myocardial hemostasis and function, thus enabling rest of body to function. The disruption of coronary development during embryogenesis results in coronary congenital defects such as coronary mispatterning, structural vascular defects, and anomalous communication of coronary vessels, they can alter coronary artery blood flow.

Such anomalies may persist after birth, occasionally they are in association with other cardiac conditions, so can severely affect cardiovascular system through haemodynamic impairment caused from shunting, ischaemia, or even sudden cardiac death, especially in young children or adolescents and young adults.

The estimated prevalence of CA anomalies is not quite clear with variable, ranging from 0.21 to 5.79% based on angiography, computed tomography (CT), and autopsy databanks [1]. Congenital anomalies of coronary arteries have in incidence about 1% in patients undergoing coronary angiography while the incidence of anomalous origination of the left coronary artery from right sinus is 0.15% and the right coronary artery from the left sinus is 0.92% [2, 3].

#### **2. Coronary artery anatomy**

In normal anatomy, the LAD and Cx originate from an aortic area located above the upper or middle third of the left coronary sinus of Valsalva (also called the left posterior sinus). The right coronary artery originates from the upper or middle third of the right sinus of the Valsalva. Normally, the coronary ostia lead an orthogonally oriented coronary proximal stem, off the aortic wall.

Of the many coronary arteries, the "primary" (or elementary) ones are defined as the three main proximal arteries: one provide circulation to the anterior septum and anterior lateral wall (the left anterior descending or LAD), another provides blood flow to the obtuse marginal region of the left ventricle (the circumflex, or Cx), and the third provides circulation to the free wall of the right ventricle (the right coronary artery or RCA). The left main trunk may serve as a common stem that joins the LAD and Cx (a common left main stem is present in about 90% of the cases and is not essential, but the LAD and CX are essential). Normally, the LAD and Cx originate from an aortic area located above the upper or middle third of the left coronary sinus of Valsalva (also called the left posterior sinus) [4]. In **Figure 1** we presented normal origin of coronary arteries.

**Figure 1.** *Normal origin of coronary artery.*

### **3. Embryology of coronary artery**

Coronary artery formation is a process involving vasculogenesis, angiogenesis, and arteriogenesis. The vasculogenesis is a process through which is formed the

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*Anomalous Origin of Coronary Arteries DOI: http://dx.doi.org/10.5772/intechopen.76912*

tion via the coronary sinus [7].

ing development [8, 9].

variant [10–12].

clusters [5].

early arterial coronary vascular system via the coalescence of the endothelial precursor cells (angioblasts), and subsequent fusion of the endothelial cell

Angiogenesis implies the generation of the new microvessels by endothelial proliferation and migration, mostly by means of controlled endothelial sprouting [6]. Coronary artery (CA) were originally thought to form bay angiogenesis from the aortic root endothelium based on anatomical facts that ones join the systemic circulation at the aortic root, whereas cardiac veins connect to the general circula-

Arteriogenesis describes the remodeling that form mature arteries by migration of supporting smooth muscle cells (SMCs) and pericytes from the epicardium dur-

Coronary anomalies are defined as those angiographic findings in which the number, origin, course and termination of the arteries are rarely encountered in general population. Coronary anomalies may occur in 1–5% of the patients undergoing coronary arteriography, depending on the threshold for defining an anatomic

A recent classification of the coronary anomalies (**Table 1**) [1] is based on

with anomalous course: interarterial, prepulmonic, intraseptal, retroaortic, posterior atrioventricular

Others (innominate artery; right carotid artery; internal mammary artery; bronchial artery; subclavian

**4. Congenital anomalies of the coronary circulation**

anatomical considerations, recognizing three categories:

c. Anomalous coronary artery location at improper aortic sinus-wrong sinus:

groove or retrocardiac, postero-anterior interventricular groove

e. Anomalous coronary artery ostium location outside sinu-tubular aorta:

b.anomalies of the intrinsic CA anatomy; and

a.anomalies of the origin and course;

c. anomalies of the termination [13, 14].

I. Anomalies of origin coronary artery connection

b. Anomalous coronary artery ostium location

1. Anomalous origin to the aorta a. Absent of left main trunk

> RCA to left sinus LCA to right sinus LCX to RCA/or sinus

d. Single coronary artery

Ascending aorta Aortic arch

LV

RCA or LCA to posterior sinus

artery; descending thoracic aorta)

*Anomalous Origin of Coronary Arteries DOI: http://dx.doi.org/10.5772/intechopen.76912*

*Vascular Biology - Selection of Mechanisms and Clinical Applications*

right coronary artery from the left sinus is 0.92% [2, 3].

we presented normal origin of coronary arteries.

**3. Embryology of coronary artery**

*Normal origin of coronary artery.*

**2. Coronary artery anatomy**

The estimated prevalence of CA anomalies is not quite clear with variable, ranging from 0.21 to 5.79% based on angiography, computed tomography (CT), and autopsy databanks [1]. Congenital anomalies of coronary arteries have in incidence about 1% in patients undergoing coronary angiography while the incidence of anomalous origination of the left coronary artery from right sinus is 0.15% and the

In normal anatomy, the LAD and Cx originate from an aortic area located above the upper or middle third of the left coronary sinus of Valsalva (also called the left posterior sinus). The right coronary artery originates from the upper or middle third of the right sinus of the Valsalva. Normally, the coronary ostia lead an

Of the many coronary arteries, the "primary" (or elementary) ones are defined as the three main proximal arteries: one provide circulation to the anterior septum and anterior lateral wall (the left anterior descending or LAD), another provides blood flow to the obtuse marginal region of the left ventricle (the circumflex, or Cx), and the third provides circulation to the free wall of the right ventricle (the right coronary artery or RCA). The left main trunk may serve as a common stem that joins the LAD and Cx (a common left main stem is present in about 90% of the cases and is not essential, but the LAD and CX are essential). Normally, the LAD and Cx originate from an aortic area located above the upper or middle third of the left coronary sinus of Valsalva (also called the left posterior sinus) [4]. In **Figure 1**

Coronary artery formation is a process involving vasculogenesis, angiogenesis, and arteriogenesis. The vasculogenesis is a process through which is formed the

orthogonally oriented coronary proximal stem, off the aortic wall.

**108**

**Figure 1.**

early arterial coronary vascular system via the coalescence of the endothelial precursor cells (angioblasts), and subsequent fusion of the endothelial cell clusters [5].

Angiogenesis implies the generation of the new microvessels by endothelial proliferation and migration, mostly by means of controlled endothelial sprouting [6]. Coronary artery (CA) were originally thought to form bay angiogenesis from the aortic root endothelium based on anatomical facts that ones join the systemic circulation at the aortic root, whereas cardiac veins connect to the general circulation via the coronary sinus [7].

Arteriogenesis describes the remodeling that form mature arteries by migration of supporting smooth muscle cells (SMCs) and pericytes from the epicardium during development [8, 9].
