A 5-month-old infant female presented with irritability, feeding intolerance, failure to thrive, a 2/6 apical holosystolic murmur, and an electrocardiogram containing Q waves in leads I and aVL. Transthoracic echocardiogram revealed an anomalous origin of the left coronary artery (LCA) from the pulmonary artery (ALCAPA).
For surgical repair, a mini-multiplane transesophageal echocardiogram probe was placed. The midesophageal (ME) 4-chamber imaging highlighted a dilated left ventricular (LV) hypokinesia in the distribution of the left anterior descending and left circumflex arteries with bright and echogenic papillary muscles (Fig. 1). The anterior leaflet of the mitral valve was mildly prolapsing, resulting in mild-to-moderate mitral regurgitation (MR). Withdrawing the probe to the ME ascending aortic short-axis (SAX) view, then making a slight leftward turn and anteflexion, we were able to center on the main pulmonary artery (PA) in the sector and revealed the anomalous origin of the LCA. The LCA was seen originating from the posterolateral aspect of the mid-main PA, in proximity to where the normal aortic origin would be. Color flow and spectral Doppler revealed diastolic retrograde blood flow in the circumflex, left anterior descending, and coursing from the left main coronary artery along the posterior PA, aligning just opposite the left lateral aspect of the ascending aorta (Fig. 2; Video 1, Supplemental Digital Content 1, http://links.lww.com/AA/B189). Advancing to the ME, the aortic valve SAX view demonstrated a trileaflet aortic valve; the left coronary cusp region was devoid of the LCA origin. The right coronary cusp was anterior and adjacent to the right ventricular outflow tract, giving rise to a prominent right coronary artery (RCA) with antegrade flow by color flow Doppler. Advancing the probe into the transgastric position then anteflexing enabled us to visualize unusually large, color flow Doppler signals in the interventricular septum, because of septal perforators and other coronary collaterals connecting the right and left coronary arterial systems.
After surgical reimplantation of the left main coronary artery to the posterolateral aspect of the aorta, an ME ascending aorta SAX view was again obtained. Unobstructed antegrade flow from the aorta into the LCA and circumflex coronary artery was demonstrated on color flow and spectral Doppler assessment (Fig. 3; Video 1, Supplemental Digital Content 1, http://links.lww.com/AA/B189). In the ME 4-chamber view, the MR, dilated LV, and echogenic papillary muscles remained essentially unchanged. The patient subsequently had an uneventful postoperative recovery.
ALCAPA comprises approximately 0.5% of all congenital cardiac disease. Left untreated, mortality is estimated at 90% in the first year of life.1 Despite this, presentation in adults is reported; however, untreated survival depends on a well-developed perfusing collateral circulation (between the RCA and the LCA systems). Extensive collateral circulation in ALCAPA is not entirely protective because of coronary steal, because the left coronary circulation may lose oxygenated blood flow into the low-pressure/resistance pulmonary system (Fig. 4). In newborns, high neonatal pulmonary vascular resistance and pulmonary pressure help maintain antegrade ALCAPA blood flow, reducing the phenomenon of coronary steal. With the subsequent natural decrease in pulmonary pressure, infant survival is highly dependent on extensive collateralization. Therefore, without surgical correction, all patients remain at risk for sudden cardiac death.2
When LV dilation with dysfunction, echogenic papillary muscles, and/or MR are seen on infant echo, ALCAPA should be suspected. Demonstrating the LCA origin from the PA by 2D echocardiography and reversal of flow in the LCA by color Doppler confirms the diagnosis.3 Other common findings in echocardiogram include a dilated RCA, abnormal diastolic color flow in the ventricular septum, and LV free wall because of prominent collateralization, LV-dilated cardiomyopathy with hypokinetic lateral and inferoseptal wall, increased echogenicity of the papillary muscles suggesting ischemia (chronic ischemia results in fibrotic change including fibroelastosis), and varying degrees of ischemic MR.1,3–5 Rare origins of ALCAPA, such as from the right PA, have been described; however, its most common origin is the posterior leftward sinus of the PA.1,3 Color Doppler is needed to overcome limitations of 2D echocardiography such as close proximity of the anomalous artery to its normal aortic origin, dropout artifact, and mistaking the transverse pericardial sinus for a normal LCA connection.6 A coronary arterial fistula into the main PA might appear similar to ALCAPA on color Doppler, but aortic examination would then find 2 coronary vessels in their normal locations.5 Cardiac catheterization is the “gold standard” in diagnosing suspected coronary anomalies including ALCAPA (Video 2, Supplemental Digital Content 2, http://links.lww.com/AA/B190) and should be used after echocardiography if the study is inconclusive.7
ALCAPA usually presents in isolation, but it is also associated with other congenital cardiac anomalies, such as patent ductus arteriosus, atrial septal defect, ventricular septal defect, tetralogy of Fallot, critical pulmonary stenosis, transposition of the great vessels, aortopulmonary window, and coarctation of the aorta.2 If there is a significant left-to-right shunt, it can provide protective physiology by maintaining PA pressures, providing relatively oxygenated antegrade blood flow to the anomalous LCA. Ventricular fibrillation after patent ductus arteriosus ligation7 and acute LV failure after ventricular septal defect closure2 were both reported in infants with unknown ALCAPA. Reversal of flow in the LCA by color Doppler and LV dysfunction may be absent when ALCAPA occurs in tandem with a significant left-to-right shunting lesion, during the neonatal stage, or when there is pulmonary hypertension.3 A high index of suspicion and careful echocardiographic interrogation of the coronary arteries will minimize the consequences of late or unrecognized diagnosis.
Verbal consent for publication was obtained from the parents of the patient at the time the patient was hospitalized. When attempting to obtain written consent, per the journal’s guidelines, we tried multiple times to contact the patient’s parents but were not successful. Permission to publish this case report was obtained from IRB. A cardiac catheterization video from another patient has been added to the manuscript; for this separate patient, written consent was obtained.
Clinician’s Key Teaching Points
By Roman M. Sniecinski, MD, and Martin M. Stechert, MD
- Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA), also known as Bland–White–Garland syndrome, is a rare congenital anomaly that is almost always fatal within the first year of life if left untreated. In fetal physiology, pulmonary artery (PA) pressure equals systemic pressure, providing myocardial perfusion through the abnormal artery. However, after birth and during infancy, PA pressure gradually decreases, resulting in retrograde flow in the left coronary artery, thereby provoking a coronary steal phenomenon and myocardial ischemia.
- Transesophageal echocardiogram can support a definitive diagnosis of ALCAPA by visualizing the left main coronary origin from the PA, as well as flow reversal in the left coronary system by color and spectral Doppler techniques. Nonspecific echocardiographic findings common in ALCAPA are those related to ischemia and congestive heart failure and include a dilated and dysfunctional left ventricle, functional mitral regurgitation, and increased echogenicity of the papillary muscles because of fibrotic changes.
- In this case of ALCAPA in a 5-month-old infant with failure to thrive, the left main coronary artery was seen originating from the posterolateral aspect of the mid-main PA. The view was obtained by withdrawing the probe from the midesophageal ascending aorta short-axis view slightly and turning the probe to the left with some anteflexion to center on the PA. Color flow Doppler demonstrated diastolic retrograde flow from the left main coronary artery into the PA.
- Although coronary angiography remains the “gold standard” for diagnosing congenital coronary anomalies, transesophageal echocardiogram can be useful in diagnosing ALCAPA by looking for retrograde diastolic flow using color flow Doppler.
Name: Jacob L. Christensen, MD.
Contribution: This author helped design the study, conduct the study, analyze the data, write the manuscript, and collected and prepared the media files.
Attestation: Jacob L. Christensen approved the final manuscript.
Name: Gautam K. Singh, MD.
Contribution: This author helped design the study, conduct the study, analyze the data, write the manuscript, and collect and prepare the media files.
Attestation: Gautam K. Singh approved the final manuscript.
Name: Jacob Aubuchon, MD.
Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.
Attestation: Jacob Aubuchon approved the final manuscript.
Name: Anshuman Sharma, MD, FFARCSI, MBA.
Contribution: This author helped design the study, conduct the study, analyze the data, write the manuscript, and anesthesiologist for the case.
Attestation: Anshuman Sharma approved the final manuscript.
This manuscript was handled by: Martin London, MD.
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