Aberrant arterial supply to left lung.

Anomalous systemic arterial supply to normal segments of the lung is a rare congenital anomaly. Although the etiology of systemic arterial supply to normal lung is still unknown, it is generally believed that this might result from an abnormal persistence of the embryonic connection between aorta and pulmonary parenchyma.[1] This disease was previously classified as Pryce Type I sequestration.[2] However, the absence of parenchymal abnormalities with a normal bronchial supply distinguishes systemic arterial supply from true pulmonary sequestration.[3] Review of published literature search shows that the systemic arterial supply is not usually associated with other anomalies.[4]

Symptoms of systemic arterialization of the left lower lobe without sequestration were variable. Most patients were asymptomatic. Hemoptysis seemed to be an unusual manifestation.[5] Computed tomography often detects the lesion [Figure 1] but gold standard of diagnosis is selective angiogram. Pathological examination of anomalous arteries documented that the walls had elastic laminae within their media, but not the muscular layer, unlike bronchial arteries. Such a wall may not withstand the high pressure of the systemic circulation.[6] This might explain the mechanism of hemoptysis in the anomalous systemic arterial supply to the normal lung.

Figure 1

Contrast CT thorax showing a single branch from the descending thoracic aorta supplying basal segments of the left lower lobe

Treatment is recommended for all patients diagnosed with this anomaly - with or without symptoms, because of its potential risk for hemoptysis.[7] Treatment options utilized in case reports include: Simple ligation of aberrant systemic artery, anastomosis to the pulmonary artery or simple lobectomy.[8] In pulmonary sequestration, resection of the sequestrated lung parenchyma is recommended because of its propensity for recurrent infection.[4] However, in pulmonary sequestration, if the parenchyma is normal, as one might encounter in systemic arterialization to lung, only a ligation of the systemic vessel by surgical ligation or coil embolization [Figure 2] may be sufficient.[5]

Figure 2

Check angiogram performed post deployment showing non-opacification of the distal aberrant artery with Amplatzer II plug in place