Aditi Gupta1, Munesh Tomar2 1 Department of Pediatrics, Lincoln Medical Center, New York, NY, USA 2 Department of Pediatrics, LLRM Medical College, Meerut, Uttar Pradesh, India
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Correspondence Address: Dr. Munesh Tomar Department of Pediatrics, LLRM Medical College, Garh Road, Jai Bhim Nagar, Meerut - 250 002, Uttar Pradesh India
Source of Support: None, Conflict of Interest: None
Congenital coronary artery anomalies occur either in isolation or in association with other congenital heart disease. With the advent of multimodality imaging, the number of incidentally detected anomalies of coronary origin has risen over the last decade. The clinical presentation of these anomalies can range from being asymptomatic to serious morbidity and mortality, including sudden cardiac death in children and adolescents. We review the most common coronary anomalies and various echocardiographic views used to image the coronary arteries origin, size, and flow.
Keywords: Anomalous origin of the left coronary artery from the pulmonary artery, coronary anomalies, echocardiography, Kawasaki disease
How to cite this article: Gupta A, Tomar M. Coronary Artery Anomalies: Echocardiographic Evaluation. J Indian Acad Echocardiogr Cardiovasc Imaging 2020;4:362-9
How to cite this URL: Gupta A, Tomar M. Coronary Artery Anomalies: Echocardiographic Evaluation. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2020 [cited 2021 Apr 13];4:362-9. Available from: https://www.jiaecho.org/text.asp?2020/4/3/362/303946
Echocardiography: General Principles of Coronary Imaging
Imaging of the coronary arteries in children is best performed with the use of the highest frequency transducer relative to patient's size to provide superior gray-scale resolution (i.e., 8, 10, or 12 MHz). However, attempts should be made to use lower frequency transducers to demonstrate color Doppler flow as higher frequency transducers may not be sensitive enough for color Doppler imaging of coronary arteries
Coronary vessel has the best resolution when the vessel is perpendicular to the beam in two-dimensional imaging, while color Doppler measurement of flow velocities is most accurate when the beam is parallel to flow
Coronaries are best imaged from a parasternal short-axis view, in which both CA origins can be visualized [Figure 1]a, [Figure 1]b and [Figure 2]a, [Figure 2]b. When the aortic sinus is imagined as clock, the left main coronary artery (LCA) origin normally arises at approximately 4 o'clock, and the right coronary artery (RCA) arises at approximately 11 o'clock. Clockwise rotation of the transducer in the parasternal short-axis view allows for imaging of the LCA as it bifurcates into the left anterior descending branch (LAD), which courses along the anterior interventricular groove, and the left circumflex branch (LCx), which courses in the left anterior atrioventricular groove. In contrast, counterclockwise transducer rotation facilitates imaging of the RCA
Frame rate and Nyquist limit are important factors in imaging coronary arteries. Since the heart rates in children are typically higher than in adults and coronary vessels are small, superficial structures, reducing depth and sector size helps in improving frame rate., For color imaging, a Nyquist limit of 30 cm/s may be used as the starting point with gradually lowering the limit until color flow in coronary arteries is detected [Figure 1]b and [Figure 2]b
An electrocardiographic tracing is necessary to correctly assess CA blood flow. While RCA flow occurs in both diastole and systole., Left CA flow occurs predominantly in diastole
When coronary arteries are not adequately visualized with echocardiography, other imaging modalities (i.e., computed tomography, magnetic resonance imaging, or cardiac catheterization) may need to be considered.
Figure 1: Parasternal short-axis view at the level of great vessels showing the normal origin of coronaries. (a) Origin of the left main coronary artery from left-facing sinus and proximal course of the left main coronary artery and left anterior descending is seen (arrow). (b) Same view with color flow mapping showing forward flow in the left main coronary artery (red color). Also, note antegrade flow in the right coronary artery. (c) Slight clockwise rotation from standard parasternal short axis view profiles length of the left anterior descending artery. PA: Pulmonary artery, Ao: Aorta, LCA: Left coronary artery, Cx: Circumflex coronary artery, LAD: Left anterior descending artery, RCA: Right coronary artery
Figure 2: Parasternal short-axis view showing the origin of the right coronary artery from the right sinus (arrow) is seen on two-dimensional (a) and color flow mapping (b). PA: Pulmonary artery, Ao: Aorta, LCA: Left coronary artery, Cx: Circumflex coronary artery, LAD: Left anterior descending artery, RCA: Right coronary artery
Classification of Coronary Anomalies Observed in Human Hearts
Following classification has been used to define coronary anomalies:,
Anomalous pulmonary origin of coronaries
Anomalous origin of left CA from the pulmonary artery
LAD artery alone from the pulmonary artery
LCx artery from the pulmonary artery
Anomalous origin of right CA from the pulmonary artery.
Anomalous aortic origin of coronaries
Location of coronary ostium within proper aortic sinus of Valsalva but tangential origin (for each artery): high, low, commissural
Anomalous location of coronary ostium outside normal “coronary” aortic sinuses
Origin from noncoronary sinus
Origin from opposite, facing “coronary” sinus.
LCA arising from right anterior sinus with anomalous course
Retroaortic or posterior
Subaortic or septal
Prepulmonary or anterior.
RCA arising from left posterior sinus with anomalous course similar to the previous situation
Isolated LAD artery or Isolated LCx from the right anterior sinus
Single coronary artery (from left or right sinus)
Anomalies of coronary branching
Absent LCA, separate LAD artery, LCx origin
LCx from RCA
Dual LAD artery, posterior descending artery.
Coronary arteriovenous fistula—draining to superior vena cava, coronary sinus, right atrium, right ventricle, pulmonary artery, pulmonary vein, left atrium, left ventricle.
Anomalous Origin of Left Coronary Artery from Pulmonary Artery
Anomalous origin of the LCA from the PA (ALCAPA), also called Bland-White-Garland Syndrome is a rare CA anomaly, with a reported incidence of 1 in 300,000 children.
This CA anomaly has a high mortality rate of 90% in infants if they do not undergo surgical repair in the 1st year of life. The heart develops normally in fetal life and after birth as pressure in the pulmonary trunk falls, the coronary artery pressure falls and the perfusion of the left ventricle becomes inadequate, which leads to decrease of left ventricular function and increase of left ventricular end-diastolic pressure compromising the perfusion further leading to myocardial ischemia.
The typical time of presentation depends on the extent of collateralization from RCA to LV myocardium. Children with inadequate collateralization present in the first few weeks of life related to the fall in pulmonary vascular resistance with signs of myocardial ischemia, which present clinically as tachypnea, pallor, feeding intolerance, and failure to thrive. Children with well-developed collateral flow usually have a delayed clinical presentation into adolescence as the LV systolic function remains well preserved.,, These patients usually are diagnosed when Echo is done for other reasons or for the presence of a cardiac murmur or exercise intolerance; very rarely they may present with sudden cardiac death as adults. In patients with large postricuspid shunts (ventricular septal defect, patent ductus arterious, atrioventricular canal defect etc.,), pulmonary artery pressures remain elevated, leading to maintained antegrade flow from pulmonary artery to LCA and preservation of left ventricular function. With the closure of shunt lesion, these children develop severe left ventricular dysfunction, it is of utmost importance to profile coronary arteries origin in all patients undergoing surgical intervention.
The imaging modality of choice for the diagnosis of ALCAPA in infants is Transthoracic Echocardiography. Diagnosis is best made by in parasternal short-axis and long-axis planes, which demonstrates the anomalous origin of the LCA and its two branches from the PA with retrograde flow [Figure 3]a, [Figure 3]b and [Video 1], [Video 2]. In some cases, direct visualization of LCA from the pulmonary artery becomes a challenge as LCA falsely appears to connect to aortic sinus due to deficiency in lateral resolution.
Figure 3: Echocardiography of an infant with anomalous origin of the left coronary artery from the pulmonary artery. (a) Parasternal short-axis view at the level of great vessels of showing the origin of the left coronary artery from pulmonary artery (arrow) on two-dimensional echo. (b) On color flow mapping reversal of color flow in the left main and left anterior descending is seen (blue flow instead of normal red flow). (c) Parasternal short-axis view showing dilated right coronary artery (arrow). (d) Apical four-chamber view showing dilated left ventricle with sclerosed mitral valve papillary muscle (arrow). (e) Same view on color flow mapping showing mitral regurgitation. Ao: Aorta, PA: Pulmonary artery, RCA: Right coronary artery, RA: Right atrium, LA: Left atrium, RV: Right ventricle, LV: Left ventricle, MPA: Main pulmonary artery
Dilated RCA and its tortuosity seen on two-dimensional echo [Figure 3]c
Dilatation of left atrium and left ventricle left ventricular systolic dysfunction with global hypokinesia and segmental wall-motion abnormality [Figure 3]d
Myocardial ischemia leads to wide enhancement of endocardium due to bright endocardial scarring. This scarring often includes mitral papillary muscle, which leads to ischemic mitral regurgitation [Figure 3]e and [Video 3]. These findings are suggestive of ALCAPA in patients with severe LV dysfunction
Color Doppler demonstrates reversal of flow from LCA [Figure 3]b and [Video 1], [Video 2]. LCA with normal origin demonstrates a red signal in parasternal short-axis view suggestive of blood flow away from the aortic root [Figure 1]b. In ALCAPA, there is retrograde LCA filling from PA, which is seen in color Doppler as emptying into the main PA (blue color in LCA and LAD).
Anomalous Origin of Right Coronary Artery from Pulmonary Artery
The anomalous origin of RCA from the pulmonary artery (ARCAPA) is the second most common of these conditions, with an incidence of 0.002%. The clinical presentation can vary from being asymptomatic into adulthood to sudden cardiac death.
The timing of presentation depends on the severity of ventricular ischemia, which is determined by the shunt size, presence of collateral circulation, and myocardial oxygen demands. Since right ventricular oxygen demands are usually lower than the left ventricle demands, ventricular ischemia in ARCAPA is less common than in ALCAPA.
Dilated LCA and absence of RCA from right anterior sinus
Delineation of the anomalous origin of RCA from the pulmonary artery is best seen by 2D echocardiography in parasternal short-axis view at the level of great vessels
On color flow mapping, continuous flow at the site of connection of RCA into the pulmonary artery can be visualized. The quantity of flow depends on the degree of collaterals from LCA.
Anomalous Origin of Left Anterior Descending Artery from Pulmonary Artery
Anomalous origin of the LAD artery from pulmonary artery is a very rare diagnosis which requires a very high index of suspicion. It has been reported to have an estimated frequency of about 0.0008%. Clinical presentation varies from asymptomatic to presenting with congestive heart failure, acute myocardial infarction, and sudden death depending on the extent of collaterals.
While the coronary artery origin is seen normally arising from the left aortic sinus, posterior course or absence of bifurcation raises suspicion for this anomaly
Other findings include prominent collaterals arising from dilated circumflex and RCA and reversal of flow in LAD artery on color flow mapping
Features due to myocardial ischemia, including left ventricular dysfunction, sclerosis of the anterior papillary muscle of the mitral valve with mitral regurgitation may also be present.
Anomalous Aortic Origin of Coronary Artery
Anomalous aortic origin of a coronary artery (AAOCA) is a congenital anomaly in which a coronary artery arises either from the opposite sinus of Valsalva or can rarely arise from the noncoronary sinus.
The incidence of AAOCA is reported as around 0.7%, and anomalous aortic origin of the RCA from the left sinus is much more common than the anomalous origin of the LCA from the right sinus. It is usually a benign abnormality, however, can be associated with ischemic events and sudden death in young, especially in athletes <40 years of age following strenuous activity. The factors that increase the risk of such events include ostial stenosis, intramural (within anterior wall of the aorta), interarterial (within myocardium) course between great arteries, or acute angle of takeoff from the aorta.,
This anomaly is most commonly incidentally detected when TTE is performed for other reasons. The coronary origins are best imaged in parasternal windows in transthoracic echocardiography. The evaluation includes the examination of ostium location and number and course and distribution of proximal coronary branches.
Left Coronary Artery Arising from the Right Coronary Sinus (or Right Coronary Artery)
An aberrant origin of the LCA or LAD coronary artery from the right sinus of Valsalva is a rare anomaly that has been associated with myocardial ischemia and sudden cardiac death. Depending on the anatomic relationship of the anomalous vessel to the aorta and the pulmonary trunk, the anomaly can be classified into four anatomic subtypes by Robert and Shirani [Figure 4]a,[Figure 4]b,[Figure 4]c,[Figure 4]d.
Figure 4: Origin of the left coronary artery from the right coronary sinus and its course in relation to great vessels. (a) Anterior or prepulmonic, left coronary artery courses to the left anterior to the pulmonary artery and is usually asymptomatic. (b) Posterior or retroaortic, left coronary artery courses dorsal to the ascending aorta. (c) Preaortic or interarterial, left coronary artery courses to the left and posteriorly between the aortic and pulmonary roots. This is the most common subtype and in view of compression by the aortic root, and pulmonary root has been reported to be associated with myocardial ischemia and sudden death in the young athlete. (d) Subpulmonic or septal course, left coronary artery courses to the left and inferiorly burrowing into the interventricular septum through the crista supraventricularis or outflow septum. This type is also usually asymptomatic
Figure 5: Origin of the right coronary artery from the left coronary sinus and its course in relation to great vessels. (a) Anterior or prepulmonic right coronary artery. (b) Interarterial or preaortic course of right coronary artery-sudden cardiac deaths in athletes. (c) Posterior or retroaortic course of the left coronary artery. (d) Septal or subpulmonic course of the right coronary artery. (e) Echocardiography from parasternal short-axis view showing the origin of the right coronary artery from left sinus and crossing in between two great vessels. Ao: Aorta, PA: Pulmonary artery, LCA: Left coronary artery, RCA: Right coronary artery
The acute bend of the proximal RCA at its ostium and compression of the coronary by the aorta and the pulmonary artery as it courses between these two structures are the usual causes which lead to myocardial ischemia in these patients.
Isolated Left Circumflex Artery or Isolated Left Anterior Descending Artery from Right Coronary Artery
LCx from RCA or LAD artery from RCA are common anomaly of coronary artery and most common coronary anomaly seen in patients with TGA and tetralogy of Fallot, respectively.
Four-chamber view (subcostal coronal and apical) in the posterior plane shows the course of LCx in the posterior atrioventricular groove as it arises from RCA [Figure 6]. It can also be visualized on parasternal short-axis view at the level of great vessels in which LCA continuation to LAD artery can be visualized LCx can be seen
Figure 6: Echocardiography showing origin of left circumflex from the right coronary artery. (a) Apical four-chamber view in posterior plane showing circumflex artery (arrow) from right to left. (b) Parstaernal short-axis view showing circumflex artery from right crossing posterior to the aorta to reach left atrioventricular groove (arrow). Ao: Aorta, MPA: Main pulmonary artery, RCA: Right coronary artery, RA: Right atrium, LA: Left atrium, RV: Right ventricle, LV: Left ventricle
In imaging of LAD artery from RCA, Coronary from left-facing sinus would be continuing to the circumflex artery and LAD artery would be seen arising from RCA and crossing right ventricular outflow tract [Figure 7].
Figure 7: Parasternal short-axis view showing the origin of the left anterior descending artery from the right and crossing anterior to right ventricular outflow tract (arrow). LAD: Left anterior descending artery, RCA: Right coronary artery, Ao: Aorta
Coronary artery fistulas are direct connections from one or more coronary arteries to cardiac chambers, coronary sinus or a large vessel and represent an anomaly of termination, Coronary arteriovenous fistulas are present in 0.002% of the general population. CAF may be congenital or acquired; due to infectious, traumatic, and post angioplasty or postcardiac.
Coronary artery fistula involves more commonly the LCA (39%–63%); less often the RCA (29%–55%), and least often both (7%–19%).,,, The common sites of drainage are the right ventricle in about 40% of instances, right atrium in about 25% of instances, the pulmonary artery in 15%–20% of instances. Fistulas to the left atrium or left ventricle are rare.
The clinical presentation can range from asymptomatic, which are detected incidentally, to features of CHF due to volume overload or symptoms of pulmonary hypertension.
Dilated or tortuous proximal coronary artery in parasternal short-axis view or transesophageal echocardiography [Figure 8]a
A continuous high-velocity signal is observed when the CAF drains into a low-pressure chamber, such as the right atrium [Figure 8]b and [Figure 8]c or coronary sinus; however, when it empties into a high-pressure chamber like the LV, the shunt flows only occurs during diastole
Volume overload of recipient cardiac chambers depending on the magnitude of left-to-right shunt through the fistula.
Figure 8: Echocardiography from a patient with coronary arteriovenous fistula to the right atrium. (a) Parasternal short-axis view at the level of great vessels showing dilated left coronary artery and circumflex (arrow), which continues behind the aortic root as a feeding vessel to the fistula draining into the right atrium. (b) Apical four-chamber view in posterior plane showing coronary arteriovenous fistula from circumflex to the right atrium on two dimensional and color flow mapping (c). Cx: Circumflex artery, RA: Right atrium, LA: Left atrium, RV: Right ventricle, LV: Left ventricle
Rarely, the fistula may open into a large sac, which opens into one of the cardiac chambers.
Atresia of Left Main Coronary Artery
Atresia of LCA with a lack of luminal continuity from the aortic root to LCA is very rare. The survival depends upon collaterals formation from the RCA through septal branches.
Echocardiographic features are the same as in ALCAPA except no shunt between LCA and pulmonary artery and absence of reverse flow. Echocardiographic features of atresia of LCA are:
Left ventricular dysfunction
Mitral regurgitation due to the sclerosed papillary muscle
Collaterals flow. This mimics the septal collaterals of the anomalous origin of LCA from the pulmonary artery on echocardiography, but there will be no reverse flow pattern seen in LCA and no left-to-right shunt in the pulmonary artery.
Kawasaki disease is a childhood vasculitis of unknown etiology and mainly affects children younger than 5 years of age. It is the most commonly diagnosed cause of coronary aneurysms. Coronary artery involvement with aneurysms develops in about 25% of patients with untreated Kawasaki's disease; the incidence of coronary involvement has reduced to 5%–7% after intravenous gamma globulin therapy when patients are treated within 10 days of fever onset.
The Japanese guidelines classify coronary arteries by absolute lumen diameter.
Small aneurysms-localized dilation of the internal lumen diameter but <4 mm, or dilation with an internal diameter of a segment measuring ≤1.5 times that of an adjacent segment if the child is ≥5 years of age
Medium aneurysms are defined as an internal lumen diameter between 4 and 8 mm, or an internal diameter of a segment measuring 1.5–4 times that of an adjacent segment if the child is ≥5 years
Large or giant aneurysms are defined as an internal lumen diameter >8 mm, or internal diameter of a segment measuring >4 times that of an adjacent segment if the child is >5 years.
These criteria do not account for patient size, which can substantially affect normal coronary artery dimensions, potentially leading to underdiagnosis and underestimation of the true prevalence of coronary artery dilation.
The z-score stratification proposed by AHA guidelines (2017) to determine the degree of coronary involvement:
No involvement: Z score always <2
Dilation only: Z score 2 to < 2.5; or if initially < 2, a decrease in Z score during follow-up ≥ 1
Small aneurysm: Z score ≥2.5 to <5
Medium aneurysm: Z score ≥5 to <10, and absolute dimension <8 mm
Large or giant aneurysm: Z score ≥10, or absolute dimension ≥8 m
Most of the patients have dilatation only, which is characterized by measurement more than normal range but less than maximal Z score of <2.5 for age.
In Kawasaki disease, the most common sites of coronary artery aneurysms, in decreasing frequency, are the proximal LAD, proximal RCA, left main coronary artery (LMCA) followed by LCX, Body surface area–adjusted Z scores are used to document z scores and diagnose ectasia for the proximal RCA, LMCA, and proximal LAD.,
During echocardiographic evaluation of coronary arteries, all measurements are made to measure the internal vessel diameters [Figure 9]a and [Figure 9]b. All measurements should exclude points of branching and be measured from inner edge to inner edge
The origins proximal portions of left main and its branches and RCA are best defined from parasternal short-axis view at the level of great vessels as described earlier. Apical 4-chamber view with posterior tilt is used to define the distal part of RCA in the right atrioventricular groove and of LCx in the left atrioventricular groove
Lack of tapering seen in normal coronary arteries is suggestive of pathological dilatation
Careful assessment of the internal lumen for thrombus formation is required in dilated coronary arteries, especially giant aneurysms
Valve regurgitation (mitral, tricuspid, aortic). Aortic valve regurgitation is more commonly noted with aortic root dilatation
Figure 9: Parasternal short-axis view at the level of great vessels from a child with Kawasaki disease. (a) Dilated left main coronary artery and left anterior descending artery. (b) Dilated right coronary artery. Ao: Aorta, RCA: Right coronary artery, LAD: Left anterior descending artery, LCA: Left coronary artery, LA: Left atrium, RA: Right atrium, RV: Right ventricle
After a significant coronary artery abnormality is recognized in a pediatric patient, surgery or appropriate transcatheter intervention should be performed in patients with anomalous origin from the pulmonary artery and in case of anomalous course of the coronary artery between two great vessels. The risk from a congenital coronary abnormality far outweighs the risks of surgical or catheter intervention. In the hands of an experienced echocardiographer, two-dimensional and color-flow Doppler echocardiography is one of the best diagnostic tools for congenital coronary abnormalities, and various coronary anomalies are identifiable with echocardiography while some are suspected on echocardiography. For a complete evaluation, other cardiac imaging methods like CT, MRI, and conventional angiography may be needed.
Akasaka T, Yoshikawa J, Yoshida K, Hozumi T, Takagi T, Okura H. Comparison of relation of systolic flow of the right coronary artery to pulmonary artery pressure in patients with and without pulmonary hypertension. Am J Cardiol 1996;78:240-4.
Wesselhoeft H, Fawcett JS, Johnson AL. Anomalous origin of the left cor- onary artery from the pulmonary trunk. Its clinical spectrum, pathology, and pathophysiology, based on a review of 140 cases with seven further cases. Circulation 1968;38:403-25.
Berre LL, Baruteau AE, Fraisse A, Boulmier D, Jimenez M, Gallet B, et al. Anomalous origin of the left coronary artery from the pulmonary artery presenting in adulthood: A french nationwide retrospective study. Semin Thorac Cardiovasc Surg 2017;29:486-90.
Ismail MY, Nassar MI, Hamad MA. Anomalous left anterior descending coronary artery arising from pulmonary artery in a 63 year-old male patient: Case report and literature review. Heart Views 2015;16:98-103. [PUBMED] [Full text]
Cheezum MK, Liberthson RR, Shah NR, Villines TC, O'Gara PT, Landzberg MJ, et al. Anomalous aortic origin of a coronary artery from the inappropriate sinus of valsalva. J Am Coll Cardiol 2017;69:1592-608.
Holzer R, Johnson R, Ciotti G, Pozzi M, Kitchiner D. Review of an institutional experience of coronary arterial fistulas in childhood set in context of review of the literature. Cardiol Young 2004;14:380-5.
Newburger JW, Takahashi M, Gerber MA, Gewitz MH, Tani LY, Burns JC, et al. Diagnosis, treatment, and long-term management of Kawasaki disease: A statement for health professionals from the Committee on Rheumatic Fever, Endocarditis and Kawasaki Disease, Council on Cardiovascular Disease in the Young, American Heart Association. Circulation 2004;110:2747-71.
Newburger JW, Takahashi M, Beiser AS, Burns JC, Bastian J, Chung KJ, et al. A single intravenous infusion of gamma globulin as compared with four infusions in the treatment of acute Kawasaki syndrome. N Engl J Med 1991;324:1633-9.
McCrindle BW, Rowley AH, Newburger JW, Burns JC, Bolger AF, Gewitz M, et al. Diagnosis, treatment, and long-term management of Kawasaki disease: A scientific statement for health professionals from the American Heart Association. Circulation 2017;135:927-99.