Description
A 1-month-old male child presented with cyanosis and feeding difficulties. Transthoracic echocardiography was suggestive of common arterial trunk with sinusal origin of pulmonary artery segment; the pulmonary artery confluence however could not be visualised. The patient was further referred for a CT angiography (CTA) for accurate assessment of the anatomy of the pulmonary arteries and aortic arch along with evaluation of the primary defect and any other cardiac or extra-cardiac anomaly.
CTA revealed presence of a common arterial trunk with a tricuspid truncal valve. The pulmonary artery segment was seen arising from the left posterior sinus, close to the origin of left main coronary artery and was seen continuing as left pulmonary artery and showed presence of a focal significant stenosis. The right pulmonary artery however was not seen to arise from the pulmonary artery segment; instead, it was seen arising separately from the posterior aspect of the ascending aorta (figure 1A–D). No evidence of aortic arch hypoplasia or interruption was seen.
Figure 1.
Oblique coronal (A) and axial (B) maximum intensity projection images and volume rendered images (C,D) shows sinusal origin (thin black arrow in A) of the pulmonary artery segment (*). The left pulmonary artery (LPA) arises from the pulmonary artery segment and shows significant stenosis (indicated by block arrow). Right pulmonary artery (RPA) arises from the posterior aspect of the ascending aorta (AA).
Various classification systems for truncus arteriosus have evolved over time considering the variability in the pulmonary arterial and coronary arterial origins in these patients, which have obvious therapeutic implications. Sinusal variant of truncus arteriosus, ie, origin of pulmonary artery segment from truncal sinus, is not uncommon with a reported incidence of 21% in a study of 56 heart specimens with common arterial trunk.1 However, its preoperative diagnosis is limited to only a few case reports in literature. Moreover, origin of one of the branch pulmonary arteries from the ascending aorta with resultant non-confluent pulmonary arteries has not been reported in these cases. Surgical correction for truncus arteriosus conventionally uses a valved conduit. However, in cases of sinusal origin of the pulmonary artery segment, direct anastomosis to the right ventricular outflow tract without using an external conduit may be possible because of their close proximity. It is imperative to pay careful attention to the origin of coronary arteries (left main coronary artery, in this case) to avoid injury during surgery.
Learning points.
Sinusal origin of pulmonary artery segment from truncal sinus is seen in approximately one-fifth of the patients with common arterial trunk.
While conventionally repair of truncus arteriosus uses a valved conduit, in presence of sinusal origin of the pulmonary artery segment, direct anastomosis to the right ventricular outflow tract may be possible, without using an external conduit, because of their close proximity.
Careful attention to the origin of coronary arteries (left main coronary artery, in this case) to avoid injury during surgery.
Footnotes
Contributors: AS has participated sufficiently in the conception of the idea, development of the intellectual content, design, writing and final approval of the manuscript. NNP has participated sufficiently in the conception of the idea, development of the intellectual content, design, writing and final approval of the manuscript. SK has participated sufficiently in the conception of the idea, development of the intellectual content, design, writing and final approval of the manuscript.
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests: None declared.
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Parental/guardian consent obtained.
Reference
- 1. Adachi I, Uemura H, McCarthy KP, et al. Relationship between orifices of pulmonary and coronary arteries in common arterial trunk. Eur J Cardiothorac Surg 2009;35:594–9. 10.1016/j.ejcts.2008.12.043 [DOI] [PubMed] [Google Scholar]