The anomalous origin of the left coronary artery from the distal pulmonary artery with an interarterial course: a case description

Introduction

Anomalous origin of the coronary artery from the pulmonary artery (PA) with 90% involvement of the left coronary artery (LCA) is a rare congenital anomaly, occurring in approximately 1 out of 300,000 live births (1,2). The vast majority of infants with this condition die within 1 year due to a failure to establish adequate intercoronary collateral circulation after birth. Those in whom a richer collateral circulation is established and survive remain at a higher risk of sudden cardiac death (SCD) due to endocardial ischemia despite having no or mild symptoms of myocardial ischemia (3). Echocardiography is the preferred screening method for anomalous origin of the LCA from the pulmonary artery (ALCAPA). However, when ALCAPA involves an origin from the distal PA and an interarterial course, it can further complicate the diagnosis and management of this condition.

We report the case of a 15-year-old girl who was initially diagnosed with ALCAPA with an origin from the distal PA and an interarterial course by echocardiography. The diagnosis was then confirmed by computed tomography angiography (CTA). She was successfully treated with LCA reimplantation surgery.

Case presentation

A 15-year-old girl was admitted to Wuhan Union Hospital with chest tightness and shortness of breath after activity for 1 year. Electrocardiography suggested ST-T segment changes. Subsequent transthoracic echocardiography (TTE) indicated right coronary artery (RCA) dilatation within the accelerated flow (Figure 1A) and abundant collateral circulation signals in the myocardium (Figure 1B), raising suspicions of an anomalous origin of the LCA from the PA. In the short-axis view at the level of the great arteries, the LCA seemed to originate normally from the left coronary sinus (Figure 1C), but color Doppler flow imaging (CDFI) showed that it had a reverse flow (Figure 1D; Video S1). No abnormal blood flow signals were detected at the pulmonary sinus, where the coronary artery anomalous orifice most commonly originates. Finally, a search upward along the PA located the abnormal orifice at the superomedial aspect of the distal PA, near the beginning of the right PA. The proximal segment of the LCA created a “pig-tail” appearance, which coursed between the aorta and PA, forming a typical “sandwich” sign (Figure 1E,1F; Video S2). Additionally, TTE showed severe mitral regurgitation and endocardial elastofibrosis of the left ventricle, especially the papillary muscles (Figure 1G). Eventually, the patient was diagnosed with ALCAPA (interarterial course) via TTE. Further CTA showed a clear separation between the LCA and the aorta (Figure 2A). Three-dimensional reconstruction indicated that the LCA originated from the superomedial aspect of the PA (Figure 2B).

Figure 1 Ultrasound images. (A) RCA dilatation (*) within the accelerated flow. (B) Abundant collateral circulation signals in the myocardium. (C) The LCA seemed to originate normally from the left coronary sinus. (D) Reverse flow within the LCA (yellow arrow). (E) Abnormal LCA orifice at the medial trunk wall near the beginning of the right PA. The proximal segment of the LCA coursed between the AO and PA, creating a “pig-tail” appearance (white arrow shows the course) and forming a typical “sandwich” sign. (F) The abnormal blood flow signal in the LCA between the AO and PA. (G) Severe mitral regurgitation and elastofibrosis of the endocardial and papillary muscles. AO, aorta; LCA, left coronary artery; RCA, left coronary artery; IVS, interventricular septum; LA, left atrium; RA, right atrium; LV, left ventricle; RV, right ventricle; PA, pulmonary artery.

Figure 2 CTA imaging. (A) CTA showed a clear separation between the AO and LCA (yellow arrow). (B) Three-dimensional reconstruction of CTA revealed a high origin of the LCA from the PA. CTA, computed tomography angiography; AO, aorta; LCA, left coronary artery; RCA, left coronary artery; PA, pulmonary artery; LAD, left anterior descending.

The patient received LCA reimplantation surgery and mitral valve repair. Intraoperatively, a tortuously dilated RCA was noted on the heart’s surface (Figure 3A). When the PA was opened, the LCA orifice was identified on the distal segment of the PA (Figure 3B, Video S3). Ultimately, the cardiac surgeons carefully freed the LCA and reimplanted it in the aortic wall above the left coronary sinus to reconstruct the dual coronary system.

Figure 3 Intraoperative photographs of the patient. (A) Intraoperative photo of a tortuously dilated RCA. (B) Intraoperative photo of the orifice of the LCA at the wall of the PA (yellow arrow). AO, aorta; RCA, left coronary artery; PA, pulmonary artery; RAA, right atrial appendage.

One week after surgery, the patient was successfully discharged without any complications. Postoperative TTE showed smooth blood flow within the reimplanted LCA without stenosis (Video S4).

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient’s legal guardians for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

ALCAPA is considered to be a malignant coronary anomaly that requires surgical correction. Due to the low pressure in the PA compared to the aorta, an anomalous LCA cannot receive adequate blood supply and relies on collateral circulation from the RCA, leading to a phenomenon known as “coronary steal” (3). Consequently, patients with ALCAPA can experience myocardial ischemia and even SCD due to insufficient endocardial perfusion. Notably, the risk of SCD is increased in patients with ALCAPA who also have an interarterial course, ostial tightness, and an acute takeoff angle. Echocardiography is the first-line imaging modality for screening coronary anomalies in children, which can accurately define these features; however, due to the rarity of the condition, echocardiographers often miss the diagnosis due to lack of detection experience. In this case, the LCA originated from the superomedial aspect of the distal PA, with coursing present between the aorta and PA, making it particularly challenging for the sonographer to display and interpret. This case suggests that when ALCAPA is suspected but the orifice is not visible at the level of the pulmonary sinus, it is crucial to scan upward along the PA.

Importantly, timely and accurate identification of ALCAPA via echocardiography can guide clinicians in performing further CTA for arriving at a definitive diagnosis. Through a combination of echocardiography and CTA, the anomalous origin and course of the LCA can be identified and thus inform the selection of surgical approach. Reimplantation of the LCA into the aortic wall above the left coronary sinus is the first choice. Conversely, if the LCA orifice is distant from the aorta, the Takeuchi procedure can be performed through the creation of an intrapulmonary tunnel using a parietal flap from the PA to connect the anomalous ostium to the aorta (1,4). In our case, the LCA originated from the medial wall of the PA between the aorta and the PA, running between the two arteries. Thus, the cardiac surgeon freed the anomalous LCA and reimplanted it into the aortic wall to reconstruct the dual coronary system.

Acknowledgments

Funding: This work was supported by the National Natural Science Foundation of China (grant No. 82272023).

Footnote

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-1378/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient’s legal guardians for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Gentile F, Castiglione V, De Caterina R. Coronary Artery Anomalies. Circulation 2021;144:983-96. [Crossref] [PubMed]
2. Goo HW. Anomalous Origin of the Coronary Artery from the Pulmonary Artery in Children and Adults: A Pictorial Review of Cardiac Imaging Findings. Korean J Radiol 2021;22:1441-50. [Crossref] [PubMed]
3. Chu H, Li J. Anomalous origin of left coronary artery from the pulmonary artery in an adult woman with ischemia and steal phenomena. J Nucl Cardiol 2022;29:235-8. [Crossref] [PubMed]
4. Takeuchi S, Imamura H, Katsumoto K, Hayashi I, Katohgi T, Yozu R, Ohkura M, Inoue T. New surgical method for repair of anomalous left coronary artery from pulmonary artery. J Thorac Cardiovasc Surg 1979;78:7-11.