Introduction

Scimitar syndrome is a complex congenital anomaly characterised by partial anomalous pulmonary venous return and lung hypoplasia. The co-occurrence of anomalous left coronary artery from the pulmonary artery and Scimitar syndrome is extremely rare, and few case reports in the literature exist outlining an association. ^{Reference Aly, Lizano Santamaria and Yoo1–Reference Marcondes, Ghez and Magee5} We present two siblings with Scimitar syndrome who were also found to have an anomalous left circumflex artery from the pulmonary artery and were positive for a mutation in the myelin regulatory factor gene.

The older sibling was found to have Scimitar syndrome shortly after birth and underwent catheterisation, confirming a large aortopulmonary collateral to the sequestered right lung (Figure 1). He underwent coil occlusion of this arterial collateral. An echocardiogram had shown concern for an anomalous circumflex coronary artery coming from the main pulmonary artery, which was confirmed by angiography (Figure 2). He subsequently underwent reimplantation of the anomalous circumflex coronary artery at 1 month of age. At 4 years of age, the patient underwent translocation of the Scimitar vein to the right atrium and baffle via atrial septal defect to the left atrium.

Figure 1.

Sibling 1. AP/Caudal angulation with branch pulmonary artery angiography. (^) depicts the anomalous left circumflex artery coming off of the junction of the main and right pulmonary artery and coursing in its usual fashion.

Figure 2.

Sibling 1. (a) AP angulation and (b) lateral angulation with selective angiography in the aortopulmonary collateral supplying the sequestered right-sided lung.

The younger sibling, born 5 years after the brother, was also found to have Scimitar syndrome soon after birth. The echocardiogram again had concerns for an anomalous left circumflex coronary artery from the pulmonary artery. The patient was taken for cardiac catheterisation, which confirmed a significant left-to-right shunt with elevated pulmonary artery pressures. Angiography confirmed a large aortopulmonary collateral to the sequestered lung along with the left circumflex artery coming off the distal main pulmonary artery (Figures 3 and 4 a , b ). Embolisation of the aortopulmonary collateral was performed. Due to the significant pulmonary hypertension with normal biventricular function, the patient was placed on triple medical therapy. As the pulmonary artery pressures decreased, there was concern for coronary steal causing heart failure. Due to the significant pulmonary hypertension, the patient was thought to be a poor surgical candidate for coronary artery translocation. The patient then underwent embolisation of the pulmonary artery connection of the left circumflex artery due to collateralisation from the right coronary artery (Figure 4 c , d ). To successfully do this, a microcatheter was inserted into the left circumflex artery from the pulmonary end. A 5 mm Azure plug was then advanced through the microcatheter and placed within the ostium of the left circumflex artery at the pulmonary end. The patient is now 13 months old and may undergo Scimitar vein repair in the future if clinically indicated.

Figure 3.

Sibling 2. (a) AP/caudal angulation and (b) lateral angulation with selective angiography in the anomalous left circumflex artery (^) coming off of the distal main pulmonary artery. The left circumflex artery courses in its usual fashion and has connections to the right coronary artery. (c) AP and (d) lateral angulation within the left circumflex artery more clearly showing the connection to the right coronary artery. (e) AP and (f) lateral angulations with angiography in the aortic root depicting a left aortic arch, a right main coronary (<) and left anterior descending artery (*) coming off the sinotubular junction normally.

Figure 4.

Sibling 2. (a) AP angulation and (b) lateral angulation with selective angiography in the aortopulmonary collateral supplying the sequestered right-sided lung. (c) AP angulation and (d) lateral angulation with angiography in the branch pulmonary arteries after coiling (^) of the origin of the left circumflex artery on the pulmonary artery end.

Exome sequencing was performed due to the brother’s history and revealed a maternally inherited pathogenic variant in the myelin regulatory factor gene in both brothers and their mother. The gene variant encodes a transcription factor associated with myelin regulatory factor gene-related cardiac urogenital syndrome. While myelin regulatory factor gene mutations have been identified in Scimitar syndrome, we present the first familial cases of Scimitar syndrome and anomalous left circumflex artery. To date, only one genetic association has been reported, a mutation in the FRAS1 gene, identified in a patient with both of these cardiac anomalies. ^{Reference Aly, Lizano Santamaria and Yoo1}