Anomalous origin of the left lower lobe artery from the right pulmonary artery

Case contributed by Yeuhen Yeuhenovich Tsasyuk


Admitted with a diagnosis of subaortic ventricular septal defect (VSD) and severe pulmonary hypertension. The general condition was satisfactory, without signs of infection. After echocardiography, a pulmonary sling was suspected; therefore, computed tomography was ordered.

Patient Data

Age: 1 year
Gender: Male

Anomalous origin of the lower lobe branch of LPA from RPA

Subaortic VSD 9 mm, dilated left atrium as a result of pulmonary hypertension

This patient in the first year of life has a rare congenital malformation. The upper lobe branch of the left pulmonary artery has a typical anatomy from the bifurcation of the pulmonary artery, but the left lower lobe branch arises from the right pulmonary artery. It originates below the level of the right lower lobe bronchus. It is located between the esophagus and the left main bronchus and does not compress them. In relation to the left main bronchus, it courses below and behind, has a parallel course and is not aberrant. Therefore, this case cannot be called a pulmonary sling.

Case Discussion

Aberrant left pulmonary artery or pulmonary artery sling is characterized by anomalous origin of the left PA from the right PA and passes between trachea and esophagus. It causes compression of the trachea and right mainstem bronchus, causing upper airway symptoms. These patients require a full work-up, including imaging and surgery planning.

In our case, only the lower lobe branch of the left PA has an anomalous origin. It originates below the level of the right lower lobe bronchus and is located between the left main bronchus and the esophagus, without compressing them. 

The patient underwent surgery to repair the VSD. It was decided to monitor the condition of the pulmonary arteries.

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