Coronary anatomy, anatomic variations and anomalies: a retrospective coronary angiography study

Abstract

INTRODUCTIONWith an increasing number of coronary angiography (CAG) procedures, coronary invasive procedures and cardiac bypass surgeries performed each day, knowledge of the variations, anomalies and anatomical pattern of coronary arteries is gaining in importance. Although many individuals have a normal coronary anatomy, variations and anomalies are not unusual, and may lead to complications during procedures. (1) There are two main coronary arteries that supply oxygenated blood to the myocardium -the left main coronary artery (LMCA) and the right coronary artery (RCA). The LMCA originates from the left sinus of Valsalva (SV), while the RCA originates from the right SV. There is typically no artery arising from the posterior SV. The LMCA bifurcates into the left anterior descending (LAD) artery and the circumflex artery (CXA). An additional artery called the intermediate artery (IMA) may arise at the bifurcation of the LMCA, forming a trifurcation.The LAD artery runs in the anterior interventricular sulcus, providing the penetrating septal branches. The left CXA runs along the left atrioventricular sulcus and gives rise to at least one obtuse marginal (OM) branch, while the RCA lies in the right atrioventricular sulcus and gives rise to the acute marginal branch. The IMA, which supplies the left ventricular free wall, is located anterior to the first OM artery and posterior to the first diagonal artery. It can also originate from the proximal part of the LMCA, LAD artery or CXA. In some cases, it is not possible to distinguish between the IMA and OM artery using anatomical or angiographic examinations. However, an important point of distinction is that the left ventricular free wall is supplied by the IMA.(1-3)The artery that supplies the posterior descending artery determines coronary dominance. Approximately 70%-80% of the general population is right-dominant (i.e. supplied by the RCA), while 5%-10% is left-dominant (i.e. supplied by the CXA) and 10%-20% is co-dominant (i.e. supplied by both the RCA and CXA).(3-5) A more accurate definition of dominance refers to the arterial supply to the atrioventricular nodal artery, which is generally supplied by the RCA. (3)(4)(5) Typically, there are two coronary ostia. However, in some cases where the LMCA is absent, three ostia can be detected.In individuals with such a condition, the LAD artery and CXA originate from different ostia. Absence of the LMCA is a common anomaly that can be detected in 0.4%-8% of the population. (4,5) Coronary arteries can be anatomically categorised into three groups based on their anatomical features: normal coronary anatomy, anatomic variations of the coronary artery and coronary artery anomalies (CAAs). CAAs, which are congenital disorders in the coronary anatomy that are observed in less than 1% of the general population, are evaluated using CAG series.

Evaluation of patients with coronary artery anomalies

“…Therefore, the recognition of coronary anatomical patterns is of utmost importance, particularly when identifying patients who need intervention or not. [5] Two dimensional TTE indicates the suspicion of CAF, when dilated coronary arteries are accompanied with symptoms and clinical findings. The entire epicardial trace and end point of the fistula, and continuous or turbulent flow within the fistula or at the site of termination can be seen with pulsed Doppler and color Doppler ECHO.…”

“…[2,5] The angiographic incidence and percentage of CAF among coronary artery anomalies were found to be higher in another study from Turkey (0.45% and 18.6%, respectively). [5,6] Coronary arteriovenous fistulas cause blood flow to be shunted into cardiac chambers, great vessels or other structures, by passing the myocardial capillary network. Symptoms may be caused by either coronary steal or a high left-to-right shunt flow.…”

“…[3] The incidence is around 1/50,000 at birth and 1/500 at cardiac catheterization, 0.3 to 0.4% in patients with congenital heart defects. [4,5] In one study from Turkey, the angiographic incidence and rate of CAFs was found to be 0.04% and the rate of CAFs was 5% among coronary artery anomalies. [2,5] The angiographic incidence and percentage of CAF among coronary artery anomalies were found to be higher in another study from Turkey (0.45% and 18.6%, respectively).…”

“…[4,5] In one study from Turkey, the angiographic incidence and rate of CAFs was found to be 0.04% and the rate of CAFs was 5% among coronary artery anomalies. [2,5] The angiographic incidence and percentage of CAF among coronary artery anomalies were found to be higher in another study from Turkey (0.45% and 18.6%, respectively). [5,6] Coronary arteriovenous fistulas cause blood flow to be shunted into cardiac chambers, great vessels or other structures, by passing the myocardial capillary network.…”

Morphologic Relationship Between the Coronary Arteries During Fetal Development

“…A dominant artery refers to the coronary artery providing the posterior interventricular branch (PIB) which supplies the posterior ventricular septum and frequently part of the posterolateral wall of the left ventricle (Pelter et al, 2011). The RCA is usually dominant with varying incidence ranging from 55 % to 89.6 % (Angelini et al, 2002;Kim et al, 2006;Loukas et al, 2006;Altin et al, 2015;Standring et al). and right ventricle (Drake et al, 2014).…”