Double-Right-Coronary-Artery with Anomalous  
Left Main and Septal Arteries Originating 
from the Right Coronary Sinus

Department of Cardiology, 
Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow

Anomalies of the coronary artery are often asymptomatic and are uncommon in the general population. We present a case of a double right coronary artery along with anomalous origin of the left main coronary artery and first septal perforator, all originating from the right coronary sinus. (Indian Heart J 2002; 54: 428–431)

Key Words: Coronary anomaly, Coronary arteriography, Coronary artery disease

Primary congenital coronary artery anomalies are detected in about 0.6%–1.3% of adult patients undergoing coronary arteriography.^1–4 Although some of these anomalies can cause ischemia and congestive heart failure, most are detected incidentally during coronary arteriography. The origin of the left main coronary artery (LMCA) from the right coronary sinus (RCS) or from the proximal right coronary artery (RCA) is a rare anomaly, accounting for only 1%–3% of all major coronary artery anomalies.^1–4 We report a patient in whom the LMCA originated from the RCS along with an anomalous first septal perforator and two separate RCAs from the same sinus. To the best of our knowledge, this combination of coronary anomalies has not been reported.

A 52-year-old male was referred to our center for coronary arteriography. He had complained of dyspnea on exertion (NYHA class II) and chest discomfort. Risk factors for coronary artery disease (CAD) included hypertension, noninsulin-dependent diabetes mellitus and cigarette smoking. Examination of the cardiovascular system was unremarkable. The resting electrocardiogram (ECG) revealed normal sinus rhythm with nonspecific T-wave changes. An echocardiogram demonstrated normal intracardiac anatomy and normal ventricular function. An exercise stress thallium revealed an inferoapical reversible defect.

Coronary arteriography failed to demonstrate any vessel originating from the left coronary sinus. The LMCA, separate first septal perforator and two RCAs originated from the RCS (Fig. 1). All were separately hooked. The LMCA formed an initial cranial anterior loop (coursing forward and upward in the RAO view (Fig. 2a) and to the right, forward and upward in the LAO and lateral views (Fig. 2b). After an initial cranial anterior loop, the artery coursed downward to reach the anterior interventricular groove and divided into the left anterior descending (LAD) and left circumflex (LCx) coronary arteries (Fig. 3). Both the LAD and LCx had a normal course, and gave rise to the diagonal and obtuse marginal branches, respectively (Fig. 3). Interestingly, the first septal perforator originated separately from the RCS (Fig. 4). The left coronary system was free of atherosclerotic CAD. There were two RCAs originating separately from the RCS with their ostia adjacent to each other (Figs 1, 5a and 5b). One RCA coursed in the right atrioventricular groove and then for some distance in the left atrioventricular groove after crossing the crux and terminated by giving off the posterior left ventricular (PLV) branches (Fig. 5a). The otherRCA originated through a separate ostium in the RCS and coursed anterolateral to the other RCA over the right ventricular free wall, descended towards the acute margin of the heart, and terminated as the posterior descending artery (PDA) after entering the posterior interventricular groove (Fig. 5b). Both the RCAs were also free from atherosclerotic CAD. A left ventricular angiogram revealed a normal left ventricular size, no regional wall motion abnormality and normal systolic function.

Anomalous origin of the LMCA from the RCS or proximal RCA is a rare anomaly, accounting for only 1%–3% of all major coronary artery anomalies.^1,4 In the largest study of coronary artery anomalies, Yamanaka et al.1 reported an incidence of 1.3% for origin of the LMCA from the RCS. The course taken by the LMCA after its origin is more important than its site of origin. Such an LMCA originating from the RCS courses either anterior to the right ventricular outflow tract (anterior free wall course), between the pulmonary artery and the aorta (interarterial course), posterior to the aorta (retroaortic course), or through the conal septum for a variable distance (septal course). The septal course is the most frequent but not well recognized during coronary arteriography.⁵ In studying the initial course of an anomalous LMCA, it is important to note all three components of its direction relative to the sagittal, coronal and transverse body planes (left–right, anteroposterior, and cranial–caudal), making at least two views necessary.⁵Because the RAO view best separates the normally positioned aortic and pulmonary valves, the RAO and LAO/ lateral views are most informative as suggested by Ishikawa et al.⁵ and Kimbiris et al.⁶ A caudal anterior loop indicates a septal course, caudal posterior loop a retroaortic course, a cranial anterior loop an anterior free wall course and cranial posterior loop an interarterial course.⁵ In our case, the LMCA had a cranial anterior loop which is suggestive of an anterior free wall course and was best delineated by a combination of the RAO and lateral views (Fig. 2).

The interarterial course has been found to be most frequently associated with angina pectoris, myocardial infarction and sudden death.^7–9 The magnitude of ischemic risk depends on the degree of angulation of the coronary artery after its origin from the aorta.^7,9 This acute angulation, which is often associated with a slit-like ostium is most common with an interarterial course. With increased cardiac output (i.e. exercise), the aorta dilates and, upon stretching of the aortic wall, this slit-like ostium becomes severely narrowed leading to myocardial ischemia.^7,8 However, myocardial infarction as well as sudden death has been reported in patients with an anomalous LMCA taking a course other than the interarterial course.^7,10

Anomalous origin of the first septal perforator is a rare entity.⁴ It is usually associated with anomalous origin of the LMCA,⁴ as in our case. Although the reported incidence of this anomaly is rare, it might be more common than reported. Because the size and site of origin of a normal first septal perforator vary widely, it is difficult to recognize an aberrant origin of this vessel arteriographically unless it is incidentally opacified selectively.

A double RCA is a rare anomaly. It has been reported in only a few cases.^11–13 In all these cases, it was reported as an isolated coronary artery anomaly. In one of these previously reported cases,¹² a patient was found during surgery to have a single right coronary ostium. The largest series of coronary anomalies,¹ which analyzed 126 595 coronary arteriograms, has not described this anomaly. In our case, one RCA, which coursed in the right atrioventricular groove and terminated by giving off PLV branches, was like a normally coursing dominant RCA (Fig. 5a). The second course of the RCA was like that of a large right ventricular branch and terminated as the PDA (Fig. 5b). This represents the extremely early origin of the PDA, which is a common variation of the normal coronary anatomy. Recognition of this anomaly before cardiac surgery is of paramount importance. To provide cardioplegia, all the coronary arteries have to be cannulated separately. 

We describe a patient with a combination of three coronary anomalies (anomalous LMCA, double RCA and anomalous first septal perforator), which even in isolation are rare entities. A combination of these rare coronary anomalies in a single patient with the entire coronary circulation from the RCS through four coronary ostia has not been described in the literature and forms the basis of this report. It appears that this anomaly is well tolerated, as the age of our patient was 52 years. Based on previous reports of an anomalous LMCA with an anterior free wall course, the clinical course of this entity appears to be generally benign and does not warrant aggressive management.

Correspondence: 
Dr Naveen Garg, 
Department of Cardiology, 
Sanjay Gandhi PGIMS, Raibareli Road, 
Lucknow. 
e-mail: navgarg@sgpgi.ac.in

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