Congenital anomalies of the coronary arteries represent a small proportion of cardiovascular malformations and are most often identified incidentally during coronary angiography performed for suspected atherosclerotic disease or other cardiac evaluations. These anomalies involve deviations in the origin, course, or structure of the coronary vessels and may range from benign variants to clinically significant patterns that predispose to myocardial ischemia or sudden cardiac death.

Among these variations, the presence of a super-dominant “single coronary artery” is exceptionally uncommon. In this condition, a single coronary vessel arises from the aortic root and supplies nearly the entire myocardium, taking over the distribution territories of both the right and left coronary systems. When the right coronary artery (RCA) assumes this role, it is termed a superdominant RCA, extending branches to supply areas typically served by the left anterior descending (LAD) and left circumflex (LCX) arteries.

The clinical significance of such an anomaly lies in the fact that the heart’s blood supply becomes critically dependent on a single vessel. Any stenosis, thrombosis, or occlusion in this vessel can compromise perfusion to the majority of the myocardium, leading to extensive ischemia or potentially fatal outcomes. Early recognition of this rare pattern is therefore vital, particularly in symptomatic patients or those undergoing invasive or surgical cardiac procedures.

A 47-year-old male, with no prior history of diabetes mellitus or hypertension, presented with a 10-day history of intermittent chest pain. The pain was non-radiating and not associated with syncope, palpitations, or dyspnea. On examination, his vital signs were within normal limits.

Electrocardiography (ECG) revealed a left bundle branch block (LBBB) pattern. Serum cardiac biomarkers, including troponins, were within the normal reference range, suggesting the absence of acute myocardial injury. Two-dimensional transthoracic echocardiography demonstrated mild regional wall motion abnormalities (RWMA) involving the left ventricular myocardium, with a preserved left ventricular ejection fraction (LVEF) of approximately 50%. Routine hematological and biochemical investigations were unremarkable.

Fig. 1: 3D volume reconstruction image showing superdominant RCA arising from the right coronary sinus. (White arrow). 3D, three-dimensional; RCA, right coronary artery.

Invasive coronary angiography revealed non-visualization of the left coronary arterial system, with retrograde filling of its branches from the right coronary circulation. The right coronary artery (RCA) itself demonstrated a normal angiographic appearance.

To further delineate the anatomy, computed tomography (CT) coronary angiography was performed. This confirmed the absence of a visualized proximal left main coronary artery (LMCA). The left coronary system originated directly from its bifurcation into the left anterior descending (LAD) and left circumflex (LCx) arteries at the left coronary sinus. The LAD was markedly hypoplastic, with a proximal luminal diameter of approximately 1.3 mm. Proximal segments showed adequate contrast opacification, while the mid-LAD exhibited a long segment of myocardial bridging measuring 3.8 cm. The distal LAD was poorly visualized, suggesting severe underdevelopment.

Similarly, the LCx artery appeared hypoplastic, with a proximal calibre of about.

It was a non-dominant vessel, continuing as the obtuse marginal branch.

Fig. 2: 3D volume reconstruction image showing superdominant RCA running in posterior right and left AV groove, entering LCX territory. Note the prominent PDA branch (black arrow). 3D, three-dimensional; LCx, left circumflex artery; PDA, posterior descending artery.

The RCA was identified as a superdominant vessel, measuring approximately 4.5 mm in diameter, with a mildly tortuous course. Its proximal, mid, and distal segments demonstrated excellent contrast opacification. Both the posterior descending artery (PDA) and posterolateral ventricular (PLV) branches were dominant and gave off multiple small branches supplying the inferior and lateral walls of the left ventricle. The conal and acute marginal branches were also prominent and mildly tortuous, with satisfactory contrast enhancement.

A few prominent collateral or bronchial arteries were visualized within the mediastinum, but no direct communication with the left coronary arteries was detected. The aortic valve appeared tricuspid, with incidental asymmetric thickening noted along the anterior and posterior leaflets in the region of the right coronary and non-coronary sinuses.

Fig. 3: 3D volume reconstruction image showing superdominant RCA (White arrow). Note absent LMCA. Note hypoplastic LAD (red arrow) and LCx (blue arrow) originating from left coronary sinus. 3D, three-dimensional; RCA, right coronary artery; LAD, left anterior descending artery; LCx, left circumflex artery

A coronary artery anomaly (CAA) refers to any deviation in the origin, course, or structure of the coronary arterial system, with an overall prevalence estimated at less than 1% in the general population. Reported incidence rates vary between 0.3% and 5.6% depending on the diagnostic method and population studied. Among these anomalies, a single coronary artery (SCA) is one of the rarest forms, with an incidence of roughly 0.05%. In this condition, the entire myocardium is supplied by a single coronary vessel arising from the aorta through a single ostium.

Lipton et al. proposed a classification system for SCAs, which was later refined by Yamanaka and Hobbs, based on the vessel’s origin and anatomical course. In this scheme, Group I SCAs are described as “superdominant” arteries that follow the course of either the right coronary artery (RCA) or the left coronary artery (LCA) and supply the entire heart. The superdominant RCA (R-I variant in Lipton’s classification) is exceptionally uncommon. This anomaly is frequently associated with congenital absence of the left circumflex artery (LCx) as an anatomical adaptation, allowing the RCA to perfuse territories normally supplied by the LCx. Studies suggest that approximately 90% of patients with congenitally absent LCx have a superdominant RCA. The incidence of congenital LCx absence itself has been estimated at around 0.067%.

Fig. 4: Invasive coronary angiography image showing absent LMCA (Green arrow). LMCA, left main coronary artery.

In the present case, the patient demonstrated a particularly rare combination: complete absence of the left main coronary artery (LMCA), hypoplastic left anterior descending (LAD) and LCx arteries arising separately from the left coronary sinus via a common ostium, and a single, large-calibre superdominant RCA supplying the majority of the myocardium. This anatomical pattern does not conform to any established type within the modified Lipton classification, highlighting its rarity.

The clinical importance of such anomalies lies in the heart’s heavy dependence on a single dominant vessel. Any obstructive lesion in this artery can result in widespread ischemia with potentially catastrophic outcomes. While many CAAs remain asymptomatic and are discovered incidentally, they can occasionally present with chest pain, arrhythmias, syncope, myocardial infarction, or even sudden cardiac death—particularly if the anomalous vessel’s course predisposes it to compression or compromised flow.

Recognition of such rare patterns through coronary angiography and advanced imaging, such as CT coronary angiography, is critical for accurate diagnosis, risk stratification, and surgical or interventional planning.

Fig. 5: Invasive coronary angiography image showing superdominant RCA (orange arrow).

The exact mechanism underlying clinical symptoms in patients with rare coronary artery anomalies remains unclear. Several possible explanations have been proposed, including coronary artery spasm resulting from endothelial dysfunction, compression of the vessel during myocardial contraction, acute take-off angles that impair blood flow, slit-like ostia, and intrinsic vessel hypoplasia. Another suggested mechanism is the “steal phenomenon”, in which an increased blood supply to one myocardial territory transiently reduces perfusion in other regions, leading to ischemic symptoms.

In the present case, no atherosclerotic changes were detected in the coronary vessels. This aligns with previous literature indicating that there is no consistent association between coronary artery anomalies and the development of atherosclerosis.

For clinicians, particularly radiologists and cardiologists, awareness of such anomalies is crucial. When the myocardium depends on a single dominant coronary vessel, any occlusion— whether acute or progressive—can have life-threatening consequences. Early identification of these variations ensures accurate diagnosis and appropriate management planning. Furthermore, in cases where revascularization is necessary, a thorough understanding of the patient’s coronary anatomy is essential to guide the choice of intervention and to optimize outcomes. Precise anatomical mapping combined with physiological assessment enables the selection of the most effective therapeutic strategy, ultimately improving prognosis in affected individuals.

Lipton-Yamanaka Classification

This case highlights an exceptionally rare coronary anatomy characterized by the absence of the left main coronary artery, hypoplastic left anterior descending and left circumflex arteries arising separately from a common ostium in the left coronary sinus, and a superdominant right coronary artery supplying the majority of the myocardium. Such a pattern does not conform to the established Lipton–Yamanaka classification, underscoring its uniqueness. While many coronary artery anomalies remain asymptomatic and are detected incidentally, the presence of a single dominant vessel places the myocardium at significant risk should occlusion occur, with potentially catastrophic consequences. The pathophysiology of symptoms in these anomalies is multifactorial, involving mechanisms such as vessel hypoplasia, abnormal angulation, myocardial bridging, and the steal phenomenon, rather than atherosclerotic disease alone. Early and accurate anatomical characterization through advanced imaging modalities like CT coronary angiography is essential for diagnosis, risk stratification, and planning appropriate interventions. Awareness of such anomalies among cardiologists and radiologists is critical to avoid misinterpretation during angiography, ensure safe revascularization strategies, and improve long-term prognosis in affected individuals.

1. Angelini P, Velasco JA, Flamm S. Coronary anomalies: incidence, pathophysiology, and clinical relevance. Circulation 2002;105 (20):2449–2454
2. Kim SY, Seo JB, Do KH, et al. Coronary artery anomalies: classification and ECG-gated multi-detector row CT findings with angiographic correlation. Radiographics 2006;26(02):317–333, discussion 333–334
3. Villa AD, Sammut E, Nair A, Rajani R, Bonamini R, Chiribiri A. Coronary artery anomalies overview: the normal and the abnormal. World J Radiol 2016;8(06):537–555
4. Lipton MJ, Barry WH, Obrez I, Silverman JF, Wexler L. Isolated single coronary artery: diagnosis, angiographic classification, and clinical significance. Radiology 1979;130:39–47.
5. Yamanaka O, Hobbs RE. Coronary artery anomalies in 126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn 1990;21:28–40.
6. Fugar S, Issac L, Okoh AK, Chedrawy C, Hangouche NE, Yadav N. Congenital absence of left circumflex artery: a case report and review of the literature. Case Rep Cardiol 2017; 2017:6579847
7. Hongsakul K, Suwannanon R. Congenital absence of left circumflex artery detected by computed tomography coronary angiography: a case report. Case Rep Vasc Med 2012; 2012:204657
8. Erol C, Seker M. Coronary artery anomalies: the prevalence of origination, course, and termination anomalies of coronary arteries detected by 64-detector computed tomography coronary angiography. J Comput Assist Tomogr 2011;35(05):618–624
9. McConnell SE, Collins KA. Sudden unexpected death resulting from an anomalous hypoplastic left coronary artery. J Forensic Sci. 1998;43(3):708-711.
10. Ali M, Hanley A, McFadden EP, Vaughan CJ. Coronary artery anomalies: a practical approach to diagnosis and management. Heart Asia. 2011;3(1):8-12.
11. Ali FS, Khan SA, Tai JM, Fatimi SH, Dhakam SH. Congenital absence of left circumflex artery with a dominant right coronary artery. BMJ Case Rep. 2009;2009.
12. Page HL, Jr., Engel HJ, Campbell WB, Thomas CS, Jr. Anomalous origin of the left circumflex coronary artery. Recognition, antiographic demonstration and clinical significance. Circulation. 1974;50(4):768-773.