Right Coronary Artery

The right coronary artery (RCA) is initially imaged in the LAO 30-degree view, which displays the proximal and distal RCA well, and the artery appears as the letter C. To evaluate the right posterior descending artery (rPDA) and posterior lateral branches (rPL), RAO 0-degree, cranial 30-degree view is utilized.

From: Cardiology Secrets (Fifth Edition) , 2018

Coronary Arteries and Cardiac Veins

In Imaging Anatomy: Chest, Abdomen, Pelvis (Second Edition), 2017

Anomalous Course of Left Coronary Artery

Right coronary artery

Left coronary artery

Right coronary cusp

Left coronary cusp

MIP image shows an anomalous origin of the left coronary artery arising from the right coronary cusp. The anomalous artery courses behind the root of the aorta (retroaortic).

Aorta

Right coronary artery

Right ventricular outflow tract

Left coronary artery

MIP image shows an anomalous right coronary artery arising from the left coronary cusp. The anomalous artery has a slit-like origin and courses between the aorta and right ventricular outflow tract (interarterial), 2 reasons implicated in the occurrence of sudden death with this anomaly.

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Cardiac Imaging

In Primer of Diagnostic Imaging (Fifth Edition), 2011

Coronary angiogram (Fig. 2-9, A–D)

RCA

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Conus artery

First branch of RCA

Runs anteriorly

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Sinoatrial (SA) nodal artery

Branch of RCA in 40%-55%

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Muscular branches

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Acute marginal branch

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Posterior descending artery

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Atrioventricular (AV) nodal artery

Branch of RCA in 90%

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Posterolateral ventricular branches

LCA

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Left anterior descending (LAD)

Longest vessel

Only vessel that extends to apex

Septal branches

Diagonal branches

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Left circumflex artery (LCx)

Left atrial circumflex

Marginal branches

Projections (Fig. 2-10)

LAO view projects the spine to the left (relative to the heart [i.e., on the right side of the image]). RAO projects the spine to the right (relative to the heart [i.e., to the left side of the image]).

Different projections (LAO, RAO) and angulations (caudal, cranial) are required to visualize all portions of the coronary arteries. Most commonly, the following projections are obtained:

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LAO with cranial angulation

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AP cranial or caudal angulation

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RAO cranial or caudal angulation

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Lateral (rarely used)

Although AP views are good for visualizing left main arteries, they are not as useful as RAO and LAO views because arteries overlie the spine.

Dominance

This refers to the artery that ultimately supplies the diaphragmatic aspect of the interventricular septum (IVS) and the LV.

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85% of patients have right-sided dominance: RCA is larger than LCA and gives rise to the AV nodal artery.

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10% of patients have left-sided dominance: LCA is larger than RCA and gives rise to the AV nodal artery.

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5% of patients have a balanced coronary artery tree (codominant): two posterior descending arteries are present, one from the left circumflex and one from the RCA.

Pitfalls

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Intramyocardial bridge: LAD enters deep into the myocardium and may be compressed during systole; appears normal in diastole.

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Spasm of coronary arteries may be catheter induced (spasm can be provoked with ergot derivatives during angiography).

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Totally occluded arteries/bypasses may escape detection.

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Orifice stenoses can be missed if aortic injection not performed.

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Inadequate opacification—need to see contrast reflux into aorta.

Veins

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Epicardial veins accompany arteries and drain into coronary sinus.

•

Thebesian venous system drains directly into all heart chambers.

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Functional Anatomy

Alexios S. Antonopoulos , ... Dimitris Tousoulis , in Coronary Artery Disease, 2018

Right Coronary Artery

The RCA emerges from the right sinus of Valsalva, proceeds behind the pulmonary artery, and descends through the atrioventricular groove then curves posteriorly, making a bend at the crux of the heart and continuing downward in the posterior interventricular sulcus. The RCA gives two major branches; the conus (arteriosus) artery and the sinoatrial artery. The conus artery is the first provided branch by the RCA; it originates from the ostium of the RCA or separately from the right coronary sinus and has a superior and anterior course. It supplies the right ventricle. The atrial branch is generally the second artery to be visualized; it stems from the from the proximal RCA and has a posterior course. From the atrial branch originates the sinoatrial artery, from which the artery that supplies the sinoatrial node in 50%–70% of hearts emerges, running along the anterior right atrium to the superior vena cava and encircling it before reaching the sinoatrial node. The RCA gives off multiple branches for the perfusion of the right atrium and ventricle. The greatest branch is the right acute marginal branch that supplies the right ventricle. At the course of its downward route to the posterior surface of the heart, the RCA gives off two or three branches. The artery of the atrioventricular node (in 50%–60% of hearts), which emerges from the RCA at the crux of the heart and proceeds anteriorly along the base of the atrial septum, also supplies proximal parts of the bundles of His, and the parts of the posterior interventricular septum. Other acute marginal (AM) branches, may also originate from the RCA, varying in size and number and are referred to as (from proximal to distal) AM1, AM2, AM3, etc. Throughout its route, the RCA is accompanied by branches of the cardiac nerve plexus, lymphatic vessels and small cardiac veins. The RCA is divided in proximal, mid, and distal segments. The segment of the RCA from the ostium to the origin of the first acute marginal artery is usually referred to as the proximal RCA.

Dominance refers to whether the posterior descending artery (PDA) originates from the RCA (right dominant), LCx (left dominant), or both (codominant). Approximately 80% of humans are right dominant. In right dominance, the distal RCA at the level of the crux of the heart typically bifurcates into the PDA and a posterolateral branch. The PDA courses in the posterior ventricular septum giving origin to the SA nodal artery and posterior ventricular branch. In left dominance, the PDA originates from the distal LCx. In codominance, there are right and left PDAs originating from the RCA and LCx. In right predominance (20%–25% of population) the RCA across the posterior interventricular septum and reach as far as the left marginal artery to supply the diaphragmatic surface of the left ventricle (Fig. 2.1.1).

Figure 2.1.1. Coronary circulation as shown on multiple three-dimensional reconstruction projections of a coronary computerized angiography scan. D1, first diagonal branch; LAD, left anterior descending artery; LCx, left circumflex artery; OM, obtuse marginal branch; RCA, right coronary artery.

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Angiographic Data

Morton J. Kern , Pranav Patel , in The Cardiac Catheterization Handbook (Fifth Edition), 2011

Anomalous Origin of the Right Coronary Artery from the Left Sinus of Valsalva

When the RCA arises from the left coronary cusp or the proximal LMCA, it generally follows only one path, although other courses are theoretically possible (Fig. 4-19). The RCA courses between the aorta and PA to its normal position. During RAO ventriculography, aortography, or coronary angiography, the RCA is seen "on end," anterior to the aorta, and appears as a radiopaque dot. This coronary anomaly has been associated with symptoms of myocardial ischemia, particularly when the RCA is dominant. Coronary revascularization should be considered when this anomaly is associated with symptoms of myocardial ischemia.

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Cardiovascular Structure and Function

Robert J. Laird , Scot Irwin , in Cardiopulmonary Physical Therapy (Fourth Edition), 2004

Right coronary artery system

The RCA, which originates from the right or anterior sinus of Valsalva, follows a course around the right border of the heart to the diaphragmatic surface, where it also approaches the crux 15 (see Figs. 1-5 and 1-6). The length and number of branches of the RCA, and therefore the amount of myocardial and nerve tissue it supplies, are inversely proportionate to the distribution of the circumflex artery and to a certain degree the LAD. In 86% of cases, the RCA extends around to the crux of the heart. The RCA and its branches supply most of the right ventricular muscle mass and inferior surface of the left ventricle, portions of the posterior wall, the posteroinferior aspects of the interventricular septum, and the right atrial muscle mass. In 60% of cases, the RCA supplies the sinus node artery; in 80% of cases, the RCA supplies the AV node. In addition, the RCA supplies the distal portion of the right bundle branch and the posterior division of the left bundle branch.

As has been discussed earlier, a reciprocal distribution pattern is seen between the RCA and the LCA. Autopsy studies have demonstrated three basic patterns of coronary circulation; the particular pattern is determined by which artery is primarily responsible for the blood supply of the posterior wall of the left ventricle. In approximately 86% of cases, the RCA reaches the crux of the heart and gives off the posterior descending artery, supplying the majority of the left ventricular posterior wall area (see Fig. 1-16, A ); in 12% of cases, the circumflex artery reaches the crux and gives off the posterior interventricular artery (see Fig. 1-16, B ); and in 2% of cases, both the RCA and the circumflex arteries reach the crux and supply an equal portion of the posterior wall (balanced system). The term dominant coronary system has been used to designate the coronary artery system responsible for the majority of posterior wall circulation. Based on the information provided here, 86% of cases are right dominant, 12% are left dominant, and 2% have a balanced coronary system. The term dominance, however, does not imply that the dominant artery system is responsible for the majority of the blood supply because, as has been stated, the left coronary system always supplies at least 60% to 70% of the left ventricular muscle.

An awareness of the distribution patterns of the coronary arteries, as described earlier and more thoroughly in the recommended references, is essential to the clinician whose aim is to evaluate and treat each patient as an individual. The remaining sections of this chapter make the significance of this baseline knowledge even more evident.

Table 1-1 summarizes regions of the heart typically supplied by each coronary artery system.

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Cardiac Angiography

Stephen Wilmot Miller , in Cardiac Imaging (Third Edition), 2009

Right Coronary Artery

The right coronary artery originates from the right sinus of Valsalva and continues in the right atrioventricular groove to the crux of the heart. Its ostium is usually in the upper two thirds of the sinus but may be ectopically located from slightly below the aortic valve leaflets in the left ventricle to a few centimeters above in the ascending aorta. In bicuspid aortic valves in which the two sinuses of Valsalva are placed anteriorly and posteriorly, the right coronary artery may go anterior from the sinus as compared to the more common angulation of 30 degrees to the right of the sternum in patients with tricuspid aortic valves. The right coronary artery in the LAO view is C-shaped and is conveniently divided into proximal, middle, and distal segments ( Fig. 4-5). The proximal right coronary segment lies beneath the right atrial appendage.

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Coronary CT Angiography

Ricardo C. Cury , Roberto C. Cury , in Atlas of Cardiovascular Computed Tomography, 2010

COMMENTS

The right and left coronary arteries arise from the aorta just above the aortic valve: the left main arises from the left sinus of Valsalva and the right coronary artery (RCA) from the right sinus of Valsalva. The left main artery courses to the left anteriorly and caudally and divides into the left anterior descending coronary artery (LAD) and left circumflex artery (LCX). Occasionally the left main artery can trifurcate with a ramus intermedius branch bisecting the angle between the LAD and LCX. The LAD travels anteriorly along the interventricular groove, reaching or wrapping around the apex, and gives off a number of diagonal and septal branches. The LCX courses in the left atrioventricular groove, giving off several obtuse marginal branches to the lateral and inferolateral free walls of the left ventricle. The RCA courses to the right and anteriorly and then turns caudally within the right atrioventricular groove. The RCA gives the following branches: conus branch (anterior course supplying the right ventricular outflow tract), sinus node branch (posterior course supplying the sinoatrial node, acute marginal branches to the free wall of the right ventricle, an atrioventricular nodal branch (from the distal RCA), the posterior descending artery to the inferior aspect of the interventricular septum, and posterior left ventricle (right dominant supplying the inferior wall of the left ventricle).

Case 2

Axial CT Images

Axial CT images of normal anatomy are shown in Figure 5-2.

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PERTINENT SURGICAL ANATOMY OF THE THORAX AND MEDIASTINUM

Paul Schipper , ... John C. Mayberry , in Current Therapy of Trauma and Surgical Critical Care, 2008

Coronary Arteries and Veins

Right and left coronary arteries arise from the ascending aorta. The right coronary artery supplies the right atrium, the right ventricle, the posterior one-third of the interventricular septum and the inferior portion of the septum. The left coronary artery supplies the left atrium, the left ventricle and the anterior two-thirds of the interventricular septum. Collateral circulation in the heart is minimal therefore occlusion of a coronary artery results in a specific area of myocardial infarction and dysfunction ( Figure 27).

The named coronary arteries travel just under the epicardium, superficial to the myocardium. Lacerations close to a coronary artery, but not including the artery, can be repaired with unpledgeted horizontal mattress sutures of Halsted. Alternatively, pledgeted horizontal mattress sutures may also be used, placed under the coronary bed, effectively repairing the myocardium but not occluding the coronary artery (Figure 28). Care should be taken in placing and tying the suture so as not to kink the coronary by incorporating too much myocardium. If the left anterior descending artery is the adjacent vessel being avoided, it is possible with this suture to occlude a major septal perforator diving deep to the vessel.

The venous system of the heart is centered on the coronary sinus, which receives the tributaries from the different areas of the heart and drains into the posterior aspect of the right atrium just superior to the tricuspid valve (see Figure 26B).

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Non-invasive Imaging Techniques in Coronary Artery Disease

Constantina Aggeli , ... Dimitris Tousoulis , in Coronary Artery Disease, 2018

Right Coronary Artery

The RCA normally arises from the right coronary sinus and courses in the right AV groove toward the crux of the heart (the point on the posterior surface of the heart where the AV groove transects the line of the interventricular septum and interatrial septum, forming a cross). In approximately 50%–60% of patients, the first branch of the RCA is a conus artery. The conus artery can also arise directly from the aorta (30%–35% of patients). The conus artery supplies the RV outflow tract (conus arteriosus) and forms the circle of Vieussens, an anastomosis with the LAD arterial circulation. In approximately 58% of patients, the sinoatrial nodal artery arises from the RCA; in the remaining patients (42%), it arises from the LCx artery. Multiple ventricular branches arise from the RCA, the largest of which is called the acute marginal branch.

The origin, course, and segmental coronary artery anatomy are described and used as a "road map" for precise localization of abnormalities. Dominance and the size of the LAD artery, LCx artery, and RCA are described. Typically, the number of diagonal and marginal branches is specified and their disease burden quantified. The overall size of the heart and cardiac chambers should be evaluated. LV function, including ejection fraction and wall motion, should also be assessed. The end-diastolic volume, end-systolic volume, and LV myocardial mass and thickness are easily determined. Other anatomic structures, whether cardiac or extracardiac, are not typically mentioned specifically unless they are abnormal.

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Coronary Computed Tomography Angiography

Suhny Abbara , Stephan Achenbach , in Cardiac Imaging (Third Edition), 2009

CORONARY ANATOMY

The RCA originates from the right sinus of Valsalva. The first RCA branch is the conus branch, which supplies the myocardium of the right ventricular outflow tract (RVOT). Occasionally the conus branch may have a separate ostium from the right sinus. The RCA gives rise to anterior right ventricular (RV) free wall branches and acute marginal branches that run along the angle that the anterior and inferior RV free walls form. The RCA is dominant in ≈80% of cases and runs in the right atrioventricular groove up to the crux of the heart (the point of the inferior cardiac surface where the atria and ventricles meet), where it bifurcates into a posterior descending artery (PDA) that runs within the inferior interventricular groove, and a posterior left ventricular branch (PLV) that supplies the inferior left ventricular (LV) wall (Figures 8-6, 8-7, 8-8). The PLV often gives rise to a small atrioventricular nodal branch at the crux of the heart. If the RCA is nondominant, it usually does not reach the crux of the heart, and the PDA and PLV are supplied by the left circumflex coronary artery (LCX).

The left main coronary artery (LM) origin is usually more cephalad compared to the RCA ostium. The LM originates from the left sinus of Valsalva and bifurcates within 2 cm of its origin into the left anterior descending artery (LAD) and LCX (Figures 8-9, 8-10). Occasionally there is no LM, and the LAD and LCX both originate directly from the left sinus of Valsalva (Fig. 8-11). An LM trifurcation is a situation in which there is a third branch arising from the LM between the LAD and LCX (Fig. 8-12). This branch is called ramus intermedius.

The LAD runs in the anterior interventricular groove and gives rise to septal perforators that perfuse the ventricular septum and to diagonal branches that supply the anterior LV wall. The distal LAD commonly wraps around the apex, where it may form collaterals to the PDA.

The LCX runs in the left atrioventricular groove and gives rise to obtuse marginal branches and posterolateral branches. If the PDA and PLV arise from the LCX, then the system is considered left dominant (Fig. 8-13). Codominance is present if both the RCA and the LCX provide a PDA branch.

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