Until a few decades ago, coronary artery anatomy assessment by echocardiogram (ECHO) was considered a difficult secondary task even if analyzed by other cardiovascular imaging modalities, such as angiography by cardiac catheterization. Important changes in this approach in recent years can be explained by three important aspects:1) The origin and initial course of coronary artery anomalies can be a substrate for ischemia and even sudden death in young adults;^1,22) Transthoracic echocardiography (TTE) is a non-invasive radiation-free low-cost imaging test in the frontline of cardiac assessments;3) The anatomical and functional assessment of coronary arteries is part of a transthoracic test used to diagnose congenital heart diseases.^3,4

Which congenital coronary artery anomalies are relevant and should be identified?

The classification of congenital coronary artery anomalies can be extensively sub-categorized by their anatomical and hemodynamic presentation. Historically, they were simply classified as major versus minor anomalies. Currently, a more comprehensive, broad, and detailed classification covers all anatomical variation possibilities.⁵

The first step is to know the normal pattern (Table 1) from a quantitative and qualitative point of view. Once the normal pattern is excluded, all findings should be considered for the definitive diagnosis and classification (Table 2).

Table 1

Characteristic	Variation
Number of ostia
Location	Right and left (anterior)
Proximal orientation	45˚ at 90˚ in the aortic wall
Proximal trunk	Left only (anterior descending and circumflex arteries)
Proximal course	Straight from the ostium to the end
Mean course	Extramural (subepicardial)
Branches	Suitable for dependent myocardium
Essential territories	Right coronary (free wall of the right ventricle), anterior descending artery (antero-septal wall), marginal obtuse (free wall of the left ventricle)
End	Capillary bed

Table 2

Anomalias de Origem e trajeto
1. Absence of the left coronary artery trunk: separate origin from the AD and Cx
2. Ostial location anomaly within the Valsalva sinuses:
a. High origin
b. Low origin
c. Commissural
3. Abnormal ostial location outside the Valsalva sinuses:
a. Posterior aortic sinus (non-coronary)
b. Ascending aorta
c. Left ventricle
d. Right ventricle
e. Pulmonary artery:
I. LC originating from the posterior sinus
II. Cx originating from the posterior sinus
III. AD originating from the posterior sinus
IV. RC originating from the posterior sinus
V. Ectopic origin of the pulmonary artery (outside the posterior sinus of the pulmonary valve):
1. Anterior sinus
2. Pulmonary trunk
3. Pulmonary branches
f. Origins of the other arteries (aortic arch, innominate artery, right carotid, mammary, bronchial artery, subclavian)
4. Anomalous origin of different Valsalva sinus coronaries (includes single coronary origin):
a. RC originating from the left Valsalva sinus with an anomalous course:
I. Posterior course to the atrioventricular junction (retrocardiac)
II. Posterior course to the aorta (retroaortic)
III. Between the aorta and the pulmonary artery (intramural)
IV. Intraseptal
V. Anterior to the pulmonary outflow tractr
b. AD originating from the right anterior sinus with an anomalous course:
I. Between the aorta and the pulmonary artery (intramural)
II. Intraseptal
III. Anterior to the pulmonary outflow tract
IV. Posterior to the interventricular septum
c. Cx originating from the right anterior sinus with anomalous course:
I. Posterior course to the atrioventricular junction
II. Posterior to the aorta (retroaortic)
d. LC originating from the right anterior sinus with anomalous course:
I. Posterior to the atrioventricular junction
II. Posterior to the aorta (retroaortic)
III. Between the aorta and the pulmonary artery
IV. Intraseptal
V. Anterior to the pulmonary outflow tract
VI. Posterior to the interventricular septum
End anomalies:
1. Coronary fistulas (originating from the RC or LC) for:
a. Right ventricle
b. Right atrium
c. Coronary sinus
d. Superior vena cava
e. Pulmonary artery
f. Pulmonary vein
g. Left atrium
h. Left ventricle

The objective of this review is to focus on anomalies originating from the coronary arteries of the aorta but from a different Valsalva sinus (from opposite sinuses), which have challenged pediatric and adult cardiologists.

How should equipment be adjusted to assess coronary anatomy?

Advanced equipment has favored the diagnosis of structures such as the coronary arteries. Some equipment comes with specific settings for this assessment that adjust automatically. However, some tips or basic rules can be very useful and improve diagnostic accuracy as follows:

Use tranducers with high-frequency as often as possible, even in adult patients (pediatric transducers with a frequency > 8 MHZ); focus on the coronary arteries in the field near the sector.

Decrease compression (to enable more distinct identification of the coronary arteries).

Use the long axis/short axis parasternal window possibly one intercostal space upward: rotate it clockwise toward the left coronary artery and counterclockwise toward the right coronary artery, pointing toward the right shoulder. All movements must be very subtle.

Never use still imaging for diagnostic purposes: Due to the size of the arteries and the possibility of false diagnosis, it is important to evaluate them very slowly, usually frame by frame. A real-time assessment is not ideal as an important translation of the coronary arteries occurs during the cardiac cycle.

Color Doppler evaluation is mandatory (with speed adjustments).

Anomalies originating from opposite sinuses occur in around 1% of the general population.¹ One of the great challenges is that most patients remain asymptomatic; when they become symptomatic, most present with a more serious event. Right coronary anomalies originating from the left sinus are more frequent; however, left coronary anomalies originating from the right sinus have the greatest risk for ischemic events. Anatomical risk factors include: An interarterial and intramural course, slit ostium, and acute emergence angle tangent to the vessel wall. All of these possibilities increase the risk for ischemic events, ventricular arrhythmias, and sudden death. Exhausting physical exercise increases the chance of sudden death, making this entity the second cause of sudden death in young athletes after hypertrophic cardiomyopathy.²

Despite controversies and discussions about athlete screening protocols, the echocardiographer should be prepared to make this diagnosis as it is the method of choice for this population. TTE has excellent diagnostic accuracy at detecting the ostium and the proximal course of the coronary arteries.⁶ However, as it is operator-dependent, the expertise of this professional makes this cardiovascular imaging modality the key piece in an algorithm for diagnosing this congenital heart disease.

To assess diagnostic quality and establish guidelines and algorithms, a multicenter study reviewed the vulnerable points of echocardiographers in recognizing the most important anatomical markers.^3,7

When emerging from the left sinus, the initial epicardial course of the normal left coronary artery is short (in adults < 4 cm) before dividing into circumflex (Cx) and anterior descending (AD) arteries. The RC originates from the right Valsalva sinus and runs behind the pulmonary artery, below the right atrial appendage, and along the right atrioventricular groove (Figure 1).

Figure 1 AD: anterior descending artery; AO: aorta; Cx: circumflex artery; LC: left coronary artery; M: mitral valve; RC: right coronary artery; T: tricuspid valve.

There are several alternative courses anomalous according to the origin of the coronary arteries (Figure 2). The anomaly originating from the LC of the right sinus and the RC originating from the left sinus allow an interarterial course (between the aorta and the pulmonary artery). In both, the coronary artery may originate from a single ostium or from separate ostia. (Figure 3).

Figure 2 AD: anterior descending artery; Cx: circumflex artery; LC: left coronary artery; LCC: left coronary cusp; M: mitral valve.RC: right coronary artery; RCC: right coronary cusp; NCC: non-coronary cusp; T: tricuspid valve.

Figure 3 LC: Left coronary artery; RC: Right coronary artery .

The echocardiographic image in the short-axis parasternal plane, with the transducer pointed at the patient’s left shoulder, delimits the initial course between the two vessels, with a space (echogenic) separating it from the arterial wall (Figure 4). Another very important detail is the ostium position in relation to the commissure. The ideal position would be equidistant (in the middle of the Valsalva sinus), as it would reduce the risk of ostial stenosis and, in cases of surgical treatment, would facilitate the surgical technique. It is important to highlight that the visualization of the coronary commissures and ostia with very subtle movement indirectly informs that there is no high coronary origin (above the sinotubular junction [STJ]).

Figure 4 AD: anterior descending artery; Cx: circumflex artery; LC: left coronary artery; RD: right coronary artery.

The second anatomical marker, and perhaps the most important as a predictor of ischemic events, is the proximal RC or LC intramural course originating from the opposite sinus. Unfortunately, it is also the most diagnostically challenging. Histologically, it is defined as sharing of the tunica media by the coronary artery and the aorta (Figure 5). An ECHO diagnosis is made using the same two-dimensional image associated with color Doppler, which is mandatory (Figures 6 and 7). The first characteristic is the angulation of the proximal portion of the coronary artery at an acute angle (< 30 degrees) and the diastolic flow in the proximal course located “inside” the wall of the aorta (Video 1). One of the most remarkable and specific characteristics is called diastolic “hang-up” (Videos 2 and 3), which means the final diastolic flow in this portion, practically when it would no longer have anterograde flow. In addition to being essential for diagnosis, color Doppler should be explored and, often, subtle changes in the direction of the ultrasound beam can enhance the flow tangent to the aortic wall. Always remember to adjust the speed of the color flow mapping. A pulsed Doppler pattern is also valuable despite technical, angulation, and translation of the heart difficulties. As for anatomical markers, the presence of separated ostia is related to a higher incidence of an intramural course.⁸ An origin very close to the commissure must also be reported, as it would be a non-compliant area contributing to flow restriction.

Figure 5

Figure 6 AD: anterior descending artery; Cx: circumflex artery; LC: left coronary artery; RC: right coronary.

Figure 7 AD: anterior descending artery; Cx: circumflex artery; LC: left coronary artery; RD: right coronary artery.

Video 1

Video 2

Video 3

The coronary ostia follow a normal pattern, which is usually equidistant from the commissures below the STJ. A high origin is identified when the origin is above the STJ (Figure 8). This anomaly alone would not represent risk of ischemic events; however, the possibility of an ostial anomaly or compression, or even of an acute angle at the origin (< 45 degrees) can be associated with high output. Echocardiographically, the standard long-axis parasternal plane requires some modification, with an angle of around 30 degrees toward the patient’s right shoulder (Video 4).

Figure 8

Video 4

In the current era, multimodality is already well established and used precisely to complement and help establish an assessment and definition algorithm for possible therapeutic decision-making that may even be surgical.³

The role of the pediatric cardiologist and echocardiographer is consolidated within the circle of care even for adult patients, especially young athletes. National and international guidelines are unanimous in establishing the role of these professionals as a pillar for an appropriate diagnosis of these anomalies and adequate conduct, especially for young athletes whose future depends on cardiovascular system integrity.⁹