**4. Prevalence**

Data are numerous in literature about the angiographic prevalence of congenital coronary abnormalities. The latter are found in >1% including abnormalities of origin and

Proximal Anomalous Connections of Coronary Arteries in Adults 193

hundred-and four (0.2%) high take-off from the aorta, most commonly the RCA, were reported in a large study (Yamanaka et al., 1997). In only one study (Angelini et al., 1999), an anomalous connection with an unusual site of the appropriate sinus was noticed, regarding the RCA without exception, with a prevalence of 1.1%. Few studies distinguished origin from the opposite sinus and from the contralateral artery. In the CASS study, among 71 anomalous origins, 52 (73%) arose from the opposite sinus and 19 (27%) from the

Type of anomaly Number % Anomalous aortic connection of the left main coronary artery 49 0.02

coronary artery 55 0.02 Anomalous aortic connection of the circumflex coronary artery 636 0.3 Anomalous aortic connection of the right coronary artery 226 0.1 Anomalous connection with the pulmonary artery 18 0.008 Single artery 83 0.04 Table 4. Angiographic prevalence of abnormalities of the coronary arteries according to the

A more accurate analysis of ANOCOR needs other imaging modalities. The diagnosis of some ANOCOR suspected during conventional angiography should be confirmed by cardiac CT scan. The studies (Fujimoto et al., 2011, Rodriguez-Granillo et al. 2009, Schmitt et al., 2005) assessing the prevalence of ANOCOR with CT scan reported a higher rate of abnormalities, even if the patients referred for CT following selective coronary angiography were excluded (table 5). This fact is due on several reasons. On the one hand, a more accurate diagnosis of ANOCOR is performed with CT scan in comparison with conventional coronary angiography. On the other hand, some patterns of ANOCOR are easily discovered only by CT scan, such as anomalous connection with an unusual site of the appropriate sinus, high take-off form the aorta or orthotropic origins from the clockwise or counterclockwise rotated aortic root (Schmitt 2005). With these additional abnormalities, the CT prevalence of ANOCOR, in a cohort pooling 8,184 adults from 3 studies (table 5), is of 1.3%.

Anomalous aortic connection of the left anterior descending

type of coronary artery and connection in a population of 236,694 adults.

Computed tomography n

Fujimoto, 2011 5,869 74 1.3 Rodriguez-Granillo, 2009 577 6 1.0 Schmitt, 2005 1,738 24 1.4 Total 8,184 104 1.3 Table 5. Computed tomography prevalence of anomalous connections of the coronary

The prevalence of ANOCOR in a general population, for example at birth, remains unknown. Large studies based on an autopsy population without methodological biases are lacking. Otherwise, the aforementioned angiographic prevalence involves, almost without

Anomalous connections n

Anomalous connections %

contralateral artery (Click et al., 1988).

Authors

arteries in adult populations.

exception, adult populations.

distribution, anomalies of coronary termination, and often some anatomical variants. If any anatomical pattern observed in >1% of an unselected population is considered as normal or variant of normal, then an anomalous origin of the coronary arteries is not exceptional. Indeed, the angiographic prevalence is around 0.5% in a cohort pooling several studies published since 1990 (Angelini et al., 1999, Aydinlar et al., 2005, Cieslinski et al., 1993, Garg et al., 2000, Kardos et al., 1997, Ouali et al., 2009, Rigatelli et al., 2003, Tuncer et al., 2006, Yamanaka et al., 1990) and with the possibility to individualise clearly the following ANOCOR: anomalous connection with the opposite sinus or non-coronary sinus, anomalous connection with the contralateral coronary artery, single coronary artery, and anomalous connection with the pulmonary artery. The latter was excluded in one study (Ouali, 2009). In this large (n=236,694) and relatively homogeneous cohort of adults with no structural congenital defect, 1 067 anomalous origins were identified, therefore a mean prevalence of 0.45% (table 3). The latter is ranged between 0.2 and 1.7%. The highest prevalence is observed in the sole prospective study, rather performed by a well-renowned team, recognized as an expert in the field of ANOCOR (Angelini et al., 1999). Otherwise, a misdiagnosis (as in most cases of "missing" coronary arteries) may explain some differences of prevalence, especially in the old retrospective studies. The high take-off from the aorta and the anomalous connection with an unusual site of the appropriate sinus were not included in this cohort.


Table 3. Angiographic prevalence of proximal anomalous connections of the coronary arteries in adult populations.

The prevalence of ANOCOR varies according to the type of coronary artery and connection (table 4). The most frequent anomaly involves the CX coronary artery with a prevalence of 3/1 000, while the anomalous connection with the pulmonary artery is the less frequent abnormality with a prevalence of 8/100 000. Both anomalous connections of the LMCA and of the LAD coronary artery are observed with a prevalence of 2/10 000. The prevalence of an ectopic origin of the RCA is of 1/1 000. The related frequency (4/10 000) of a single artery is certainly overestimated in the cohort. Indeed, contrary to the classification used in our review, most previous studies categorized a single ostium with an abnormal proximal course, as a single artery. Some patterns, generally not counted, are identified with difficulty by angiography. That is the case of an abnormal origin above the sinotubular junction. Two-

distribution, anomalies of coronary termination, and often some anatomical variants. If any anatomical pattern observed in >1% of an unselected population is considered as normal or variant of normal, then an anomalous origin of the coronary arteries is not exceptional. Indeed, the angiographic prevalence is around 0.5% in a cohort pooling several studies published since 1990 (Angelini et al., 1999, Aydinlar et al., 2005, Cieslinski et al., 1993, Garg et al., 2000, Kardos et al., 1997, Ouali et al., 2009, Rigatelli et al., 2003, Tuncer et al., 2006, Yamanaka et al., 1990) and with the possibility to individualise clearly the following ANOCOR: anomalous connection with the opposite sinus or non-coronary sinus, anomalous connection with the contralateral coronary artery, single coronary artery, and anomalous connection with the pulmonary artery. The latter was excluded in one study (Ouali, 2009). In this large (n=236,694) and relatively homogeneous cohort of adults with no structural congenital defect, 1 067 anomalous origins were identified, therefore a mean prevalence of 0.45% (table 3). The latter is ranged between 0.2 and 1.7%. The highest prevalence is observed in the sole prospective study, rather performed by a well-renowned team, recognized as an expert in the field of ANOCOR (Angelini et al., 1999). Otherwise, a misdiagnosis (as in most cases of "missing" coronary arteries) may explain some differences of prevalence, especially in the old retrospective studies. The high take-off from the aorta and the anomalous connection with an unusual site of the appropriate sinus were not

> Anomalous connections n

Anomalous connections %

included in this cohort.

arteries in adult populations.

Coronary angiograms n

Angelini, 1999 1,950 34 1.7 Aydinlar, 2005 12,059 39 0.3 Cieslinski, 1993 4,016 22 0.5 Garg, 2000 4,100 35 0.9 Kardos, 1997 7,694 39 0.5 Ouali, 2009 7,330 20 0.3 Rigatelli, 2003 5,100 34 0.7 Tuncer, 2006 70,850 110 0.2 Yamanaka, 1990 126,595 734 0.6 Total 236,694 1,067 0.45 Table 3. Angiographic prevalence of proximal anomalous connections of the coronary

The prevalence of ANOCOR varies according to the type of coronary artery and connection (table 4). The most frequent anomaly involves the CX coronary artery with a prevalence of 3/1 000, while the anomalous connection with the pulmonary artery is the less frequent abnormality with a prevalence of 8/100 000. Both anomalous connections of the LMCA and of the LAD coronary artery are observed with a prevalence of 2/10 000. The prevalence of an ectopic origin of the RCA is of 1/1 000. The related frequency (4/10 000) of a single artery is certainly overestimated in the cohort. Indeed, contrary to the classification used in our review, most previous studies categorized a single ostium with an abnormal proximal course, as a single artery. Some patterns, generally not counted, are identified with difficulty by angiography. That is the case of an abnormal origin above the sinotubular junction. Two-

Authors

hundred-and four (0.2%) high take-off from the aorta, most commonly the RCA, were reported in a large study (Yamanaka et al., 1997). In only one study (Angelini et al., 1999), an anomalous connection with an unusual site of the appropriate sinus was noticed, regarding the RCA without exception, with a prevalence of 1.1%. Few studies distinguished origin from the opposite sinus and from the contralateral artery. In the CASS study, among 71 anomalous origins, 52 (73%) arose from the opposite sinus and 19 (27%) from the contralateral artery (Click et al., 1988).


Table 4. Angiographic prevalence of abnormalities of the coronary arteries according to the type of coronary artery and connection in a population of 236,694 adults.

A more accurate analysis of ANOCOR needs other imaging modalities. The diagnosis of some ANOCOR suspected during conventional angiography should be confirmed by cardiac CT scan. The studies (Fujimoto et al., 2011, Rodriguez-Granillo et al. 2009, Schmitt et al., 2005) assessing the prevalence of ANOCOR with CT scan reported a higher rate of abnormalities, even if the patients referred for CT following selective coronary angiography were excluded (table 5). This fact is due on several reasons. On the one hand, a more accurate diagnosis of ANOCOR is performed with CT scan in comparison with conventional coronary angiography. On the other hand, some patterns of ANOCOR are easily discovered only by CT scan, such as anomalous connection with an unusual site of the appropriate sinus, high take-off form the aorta or orthotropic origins from the clockwise or counterclockwise rotated aortic root (Schmitt 2005). With these additional abnormalities, the CT prevalence of ANOCOR, in a cohort pooling 8,184 adults from 3 studies (table 5), is of 1.3%.


Table 5. Computed tomography prevalence of anomalous connections of the coronary arteries in adult populations.

The prevalence of ANOCOR in a general population, for example at birth, remains unknown. Large studies based on an autopsy population without methodological biases are lacking. Otherwise, the aforementioned angiographic prevalence involves, almost without exception, adult populations.

Proximal Anomalous Connections of Coronary Arteries in Adults 195

It is admitted that a slit-like orifice, almost without exception, is associated with an intramural course. The latter means a course of the first millimetres of the ectopic vessel in the aortic media. Therefore, no adventitia exists between the coronary media and aortic media. The length of the intramural path is ranged from 5 to 25 mm, much longer for the left ANOCOR (Angelini & Flamm, 2007). An intramural course is not synonymous with a preaortic course, and inversely (Houyel & Planché, 2008). The ANOCOR arising from the opposite sinus, and without a preaortic or retroaortic course, have generally a normal orifice, while they move quickly from the aorta, and their initial courses are therefore extramural. The ANOCOR with a retroaortic course have in most cases a juxtamural course regarding the aorta, although rare observations with abnormal orifice and/or intramural course have been reported. The ANOCOR with a high take-off above the sinotubular junction may have an abnormal orifice with a vertical intramural initial course. Generally, the orifice of the anomalous connections with the pulmonary artery is circular with an extramural or juxtamural initial course. Coronary IVUS, now easily available, gives important quantitative parameters regarding the orifices and initial courses of ANOCOR (Angelini & Flamm 2007). The ellipsoid shape of an ectopic orifice is well visualized. Also important, coronary IVUS highlighted systematically a hypoplasia of the intramural

The ectopic course of an ANOCOR may be defined as the coronary path between the orifice and the point where the ectopic artery meet up with an appropriate myocardial area. The length of the ectopic course varies considerably regarding the site of ectopic ostium and relationships with the adjacent structures. The definitions of different ectopic courses are still used in an ambiguous fashion. Usually, 4 subgroups of anomalous origin of the LCA from the opposite sinus are described: anterior to pulmonary trunk, between aorta and pulmonary trunk, in ventricular septum, and posterior to aorta courses (Roberts & Shirani, 1992). For the purpose of being close to the anatomical descriptions and recent imaging contributions, we classify the ANOCOR into 7 courses relating to their links with the great vessels and/or ventricles (table 6). We chose to define each course according to

segment in comparison with the more distal, extramural segment.

type A preinfundibular course type B retroinfundibular course

type E retroaortic course

type G other ectopic courses

type C preaortic course with intramural path type D preaortic course without intramural path

type F absent proximal ectopic course

Table 6. Different courses of anomalous origins of the coronary arteries.

the closest adjacent cardiac structure (figure 9).

**5.2 Initial courses** 

**5.3 Ectopic courses** 
