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

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 variant [10–12].

A recent classification of the coronary anomalies (**Table 1**) [1] is based on anatomical considerations, recognizing three categories:

a.anomalies of the origin and course;

b.anomalies of the intrinsic CA anatomy; and

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



#### **Table 1.**

*Classification of coronary artery anomalies.*

#### **4.1 Anomalous pulmonary origin of the coronary arteries (APOCA)**

This syndrome is characterized by the origin of the coronary artery arising from the pulmonary artery. The most variant is an anomalous origin of the LCA from the pulmonary artery. (ALCAPA) [15, 16] although single-vessel origins of the RCA, LCx coronary, or LAD artery from the pulmonary artery have also been reported. If untreated, and in the absence of an adequate collateral network, most (95%) infants with APOCA will die within the first year. In the presence of an extensive collateral network, patients may survive into adulthood.

Aortography reveals a large RCA with absence of a left coronary ostium in the left aortic sinus of Valsalva, and with LAD and Cx branches filling through collateral circulation from the RCA branches. Still very delayed in filming sequence retrograde flow from LAD and LCx opacifies the LMCA and its origin from the main pulmonary artery. Still later in the filming sequence retrograde flow from the LAD and LCx arteries opacifies the LMCA and its origin from the main pulmonary artery. Once it is diagnosed, CABG surgery is recommended because of the high incidence of sudden death, cardiomyopathy and arrhythmias associated with APOCA.

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

particularly during systole and stress.

**4.3 Coronary artery fistulas**

cardiac catheterizations [20].

**4.4 Myocardial bridging**

**5. Clinical presentation**

Sinus (ACAOS).

**4.2 Anomalous coronary artery from the opposite sinus (ACAOS)**

Anomalous origin of either the RCA to the left coronary sinus or the LCA to the right coronary sinus, the proximal anomalous coronary artery (CA) may run anterior to the pulmonary trunk (prepulmonic), posterior to the aorta (retroaortic), septal (subpulmonic), or between the pulmonary artery and the aorta (interarterial). Only those with an interarterial (aorta-pulmonary) course can increase risks of myocardial ischemia, arrhythmia, syncope, and sudden cardiac death considering life threatening and clinical guidelines recommend surgical correction [17].

Numerous mechanisms of ischaemia particularly during exercise have been suggested: (1) the compression of the anomalous vessel coursing between the aorta and the pulmonary artery during increased cardiac output and expansion of the great vessels; (2) the acute angle takeoff of the anomalous vessel with further stretch during exercise, possibility accounting for a flap-like closure of the coronary ostium; (3) spasm or kinking of the anomalous vessels; and (4) the course within the aortic wall ("intramural") of the proximal segment of the anomalous vessel [13, 17]. The intramural aortic course can explain the imaging feature (angiography and echo) of CA intussusceptions into the aoric wall: the proximal segment of the anomalous vessel (segmental hypoplasia) is narrowed, and the asymmetrical lateral compression of the anomalous vessel with a silt-like or ovoid rather than circular lumen,

In **Figure 2** (A and B) we present anomalous Coronary Artery from the Opposite

Coronary artery fistulas are defined as abnormal communications between a coronary artery and a cardiac chamber or major vessel, such as to the vena cava, right or left ventricle, pulmonary vein or pulmonary artery [18, 19]. Coronary artery fistulas are rare findings, identified in 10 (0.05%) of 18,272 diagnostic

The three major coronary arteries generally course along the epicardial surface of the heart. On occasion, however, short coronary artery segments descend into the myocardium for a variable distance. This abnormality, termed myocardial bridging occurs in 5–12% patients and usually is confined to LAD [21].

Coronary steal syndrome results where an alteration of circulation patterns leads to a reduction in the blood directed to the coronary circulation. The low pressure in the pulmonary artery causes blood from the abnormal LCA to flow towards the pulmonary artery instead of towards the heart resulting in ischaemia and collateral growth. The extent of the acquired circulation between the two CAs is the major determinant of the degree of ischaemia, severity of clinical presentation, and outcome. Depending collateral vessels clinically are presented: a) the adult-type with wellestablished collateral vessels, and b) the infant-type without or with few collaterals, with early onset of symptoms when pulmonary arterial pressure decreases [22].

**5.1 Anomalous pulmonary origin of the coronary arteries (APOCA)**

*Vascular Biology - Selection of Mechanisms and Clinical Applications*

e. Ectopic connection (outside facing sinuses) of any CA to PA left sinus, trunk, or branch

2. Anomalous origin to the pulmonary artery a. LCA to posterior facing sinus (ALCAPA)

II. Anomalous intrinsic coronary artery anatomy

6. Intramural coronary artery (myocardial bridge)

7. Subendocardial coronary course

12. Ectopic origination of first septal branch

1. Inadequate arteriolar/capillary ramifications

8. Coronary crossing

10. Absent PD or split RCA 11. Absent or split LAD

III. Coronary artery interaction

*Classification of coronary artery anomalies.*

LA, LV, multiple

**Table 1.**

1. Congenital ostial stenosis or atresia (LCA, LAD, RCA, Cx)

b. LCX to posterior facing sinus c. LAD to posterior facing sinus d. RCA to anterior right facing sinus

2. Coronary ostial dimple 3. Coronary ectasia or aneurysm 4. Absent coronary artery 5. Coronary hypoplasia

f. RV

**4.1 Anomalous pulmonary origin of the coronary arteries (APOCA)**

9. Anomalous origination of posterior descending branch or septal penetrating branch

network, patients may survive into adulthood.

This syndrome is characterized by the origin of the coronary artery arising from the pulmonary artery. The most variant is an anomalous origin of the LCA from the pulmonary artery. (ALCAPA) [15, 16] although single-vessel origins of the RCA, LCx coronary, or LAD artery from the pulmonary artery have also been reported. If untreated, and in the absence of an adequate collateral network, most (95%) infants with APOCA will die within the first year. In the presence of an extensive collateral

2. Fistulae from RCA, LCA, or infundibular artery to: RV, RA, coronary sinus, superior vena cava, PA, PV,

Aortography reveals a large RCA with absence of a left coronary ostium in the left aortic sinus of Valsalva, and with LAD and Cx branches filling through collateral circulation from the RCA branches. Still very delayed in filming sequence retrograde flow from LAD and LCx opacifies the LMCA and its origin from the main pulmonary artery. Still later in the filming sequence retrograde flow from the LAD and LCx arteries opacifies the LMCA and its origin from the main pulmonary artery. Once it is diagnosed, CABG surgery is recommended because of the high incidence of sudden death, cardiomyopathy and arrhythmias associated

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with APOCA.
