Responsibility Comes with the Dominance: A Rare Case Report of Absent Right Coronary Artery with Super Dominant Left Circumflex Artery

Special Article: Radiology Case Reports

Austin J Clin Case Rep. 2023; 10(6): 1296.

Responsibility Comes with the Dominance: A Rare Case Report of Absent Right Coronary Artery with Super Dominant Left Circumflex Artery

Kritisha Rajlawot¹*; Nirmal Prasad Neupane¹; Manisha Aryal¹; Dharmanath Yadav²

¹Radiologist, Department of Radiodiagnosis and Imaging, Shahid Gangalal National Heart Center, Bansbari, Kathmandu, Nepal

²Cardiologist, Department of Cardiology, Shahid Gangalal National Heart Center, Bansbari, Kathmandu, Nepal

*Corresponding author: Kritisha Rajlawot Radiologist, Department of Radiodiagnosis and Imaging, Shahid Gangalal National Heart Center, Bansbari, Kathmandu, Nepal. Tel: +9779849928166 Email: nirmal.neup@gmail.com

Received: June 21, 2023 Accepted: August 01, 2023 Published: August 08, 2023

Abstract

Coronary artery dominance describes the source from which the Posterior Descending Artery (PDA) is arising that supplies the inferior wall. 80-85% of the times it is Right Coronary Artery (RCA) referring to right dominance, 7-13% of the times it is Left Circumflex artery (LCx) referring to left dominance and about 2-5% of the times it is originating from both the RCA and LCx making a codominant supply. A super dominant vessel is when a vessel is exceptionally huge supplying the area that the other vessel usually covers which makes cardiac circulation rely on one vessel. Here we present a rare case of absent RCA with super dominant LCx supplying the RCA territory diagnosed through Coronary Computed Tomography Angiography (CCTA). As invasive coronary angiography may not always provide sufficient information in such cases, CCTA is considered as a robust, reliable and non-invasive modality of imaging to investigate so as to avoid an ischemic insult.

Keywords: Coronary computed tomography angiography (CCTA); Absent right coronary artery; Super dominant left circumflex artery; Invasive coronary angiography

Introduction

Coronary artery dominance is simply described by the source from which the Posterior Descending Artery (PDA) is arising and supplying the inferior wall or the posterior interventricular septum. 80-85% of the times it is Right Coronary Artery (RCA) referring to right dominance, 7-13% of the times it is Left Circumflex artery (LCx) referring to left dominance and about 2-5% of the times it is originating from both the RCA and LCx making a codominant supply [1]. Amongst various presentation of coronary artery dominance, a super dominant vessel is when a vessel is exceptionally huge supplying the area that the other vessel usually covers. Different variations of the super dominant coronaries have been reported in the literature previously such as the territory of the RCA as well as the Left Anterior Descending (LAD) artery being supplied by a super-dominant LCx artery [2], super dominant RCA extending along the base of the heart to left atrioventricular groove where it is supplying the lateral wall of the left ventricle and LCx being completely absent, with no visible vessel in the upper portion of the left atrioventricular groove [3], super dominant RCA with double Posterior Descending Artery (PDA) [4], super dominant LAD supplying the apex and giving rise to the posterior interventricular artery, that is ascending along the groove until the crux cordis with continuation as a posterior lateral branch [5]. As being mentioned the super dominant vessel may present in several forms which is yet an uncommon form of anomalous coronary with an incidence of less than 0.066% [6]. As it may not have a typical clinical presentation, super dominant vessel or congenital absence of one of the coronaries or two is not a first diagnosis that comes to anyone’s mind with a symptom of acute chest pain. Therefore, here we attempt to present a rare case of absent RCA with super dominant LCx supplying the RCA territory.

Clinical History

A female patient aged 70 presented to our out-patient department with complaints of chest pain, associated with shortness of breath that relieves on rest and associated palpitation. She had a history of diabetes, hypertension and hyperlipidemia under medications. Her electrocardiography showed ST segment changes, while her cardiac enzymes were negative. Her treadmill test was however positive. Therefore, with a provisional diagnosis of stable angina at moderate efforts, she was planned for an elective invasive coronary angiography considering her age and comorbidities. During the procedure, RCA was not well visualized and hence the patient was referred to undergo Coronary Computed Tomography Angiography (CCTA) for further evaluation so as to rule out an obstructed proximal RCA or an anomaly or a dominant LCx.

Imaging Features

The patient underwent a CCTA for the evaluation of the RCA and also to rule out significant stenoses of the coronaries. There was normal origin of the left main artery from the left sinus of valsalva that was further branching into LAD and LCx arteries. The calcium scoring was significantly higher corresponding to above 800 agatston units where LAD was diffusely diseased showing about 70-80% luminal stenosis. LCx also had eccentric calcified plaques with about 20-30% luminal stenosis. However, the origin of RCA from the right sinus of Valsalva was not appreciated with an absent ostium and proximal segment (Figure 1). On the other hand, a large LCx was noted extending into the right atrioventricular groove and terminating near the right sinus of Valsalva perfusing the RCA territory (Figure 2). Clearly LCx was a dominant vessel as it was giving off the Posterior Descending Artery (PDA) (Figure 2b). Hence, a diagnosis of absent RCA with super dominant LCx supplying the RCA territory was given.

Citation: Rajlawot K, Neupane NP, Aryal M, Yadav D. Responsibility Comes with the Dominance: A Rare Case Report of Absent Right Coronary Artery with Super Dominant Left Circumflex Artery. Austin J Clin Case Rep. 2023; 10(6): 1296.