**3.1 Anomalous connection with the opposite sinus (type I)**

The ectopic orifice may be in contact with the ostium in right location or close to the latter (figure 3). The main anomalies involve a RCA arising from the opposite sinus, a left main coronary artery (LMCA), or a left anterior descending (LAD) coronary artery and/or circumflex (CX) coronary artery arising from the opposite sinus.

Fig. 3. Axial computed tomography image showing an anomalous connection of the left main coronary artery (arrow) with the opposite sinus close to the normal origin of the right coronary artery (arrow head).

#### **3.2 Anomalous connection with the contralateral artery (type II)**

By definition, the RCA is the contralateral artery of the LCA, and the LCA the contralateral artery of the RCA. In most cases, an anomalous connection in the contralateral artery results in a unique coronary ostium (figure 4).

Generally, this abnormality is not separated from the anomalous connection with the opposite sinus. In our opinion, it seems interesting to make a difference between these abnormalities. Firstly, a connection of the ectopic coronary artery with the proximal segment of the contralateral involves, almost without exception, the LCA or their branches. Secondly, in theory, the risk of intramural course can be excluded. Finally, this classification may include an anomalous origin distant from the aorta. In theses uncommon cases, the classification used in this study implies that an anomalous connection can exist between two coronary arteries whatever the level of the connection from the origin to the distal segment. The anomalous connections of the LCA with the opposite sinus or contralateral artery are generally associated with an absent LMCA in the appropriate sinus. However, rare cases of atresia of the LMCA originated from the left coronary sinus have been described (Levisman et al., 2009) with an embryonic small vessel often solely visible by CT.

The ectopic orifice may be in contact with the ostium in right location or close to the latter (figure 3). The main anomalies involve a RCA arising from the opposite sinus, a left main coronary artery (LMCA), or a left anterior descending (LAD) coronary artery and/or

Fig. 3. Axial computed tomography image showing an anomalous connection of the left main coronary artery (arrow) with the opposite sinus close to the normal origin of the right

By definition, the RCA is the contralateral artery of the LCA, and the LCA the contralateral artery of the RCA. In most cases, an anomalous connection in the contralateral artery results

Generally, this abnormality is not separated from the anomalous connection with the opposite sinus. In our opinion, it seems interesting to make a difference between these abnormalities. Firstly, a connection of the ectopic coronary artery with the proximal segment of the contralateral involves, almost without exception, the LCA or their branches. Secondly, in theory, the risk of intramural course can be excluded. Finally, this classification may include an anomalous origin distant from the aorta. In theses uncommon cases, the classification used in this study implies that an anomalous connection can exist between two coronary arteries whatever the level of the connection from the origin to the distal segment. The anomalous connections of the LCA with the opposite sinus or contralateral artery are generally associated with an absent LMCA in the appropriate sinus. However, rare cases of atresia of the LMCA originated from the left coronary sinus have been described (Levisman et al., 2009) with an embryonic small

**3.2 Anomalous connection with the contralateral artery (type II)** 

coronary artery (arrow head).

in a unique coronary ostium (figure 4).

vessel often solely visible by CT.

**3.1 Anomalous connection with the opposite sinus (type I)** 

circumflex (CX) coronary artery arising from the opposite sinus.

Fig. 4. Angiographic view showing an anomalous connection of the left main coronary artery (arrow head) with the proximal right coronary artery (arrow).
