Giant Feeding Artery from Abdominal Aorta in Intralobar Pulmonary Sequestration.

Pulmonary sequestration (PS) is a rare congenital lung malformation. We present a case of newborn with antenatally diagnosed case of PS. The baby was delivered by cesarean section to primigravida mother at 38 + 3 weeks of gestation with birth weight of 2700 g. At 20 weeks of gestation, the antenatal ultrasound showed a triangular echogenic area in left lung supplied by feeding artery from descending aorta. The baby had respiratory distress soon after birth. Computerized tomographic pulmonary angiogram revealed abnormal blood supply of left lower lobe arising from descending aorta. The feeding vessel was abnormally large and was almost half of the diameter of the aorta. The baby underwent left lower lobectomy with double ligation of feeding artery at day 7 of life and was discharged on day 14 of life. Antenatal diagnosis of congenital lung malformation helps in careful planning of perinatal care and facilitates the early diagnosis and management. Copyright:

INTRODUCTION

Pulmonary sequestration (PS) consists of a solid or cystic nonfunctioning mass of lung tissue that lacks normal communication with the tracheobronchial tree. PSs account for 0.15%–6.4% of congenital lung malformations.[1] It receives its blood supply from the systemic (rather than the pulmonary) circulation. The feeding vessel generally originates from the aorta, although other origins are the splenic artery and left gastric artery. It can be associated with congenital pulmonary airway malformation. Congenital diaphragmatic hernia, bronchogenic cyst, congenital heart disease, and gastric duplication are other associations. Antenatal diagnosis can be helpful in the postnatal care plan. We report a case of intralobar PS which was diagnosed antenatally and had a giant feeding artery arising from the abdominal aorta.

CASE REPORT

The present case was a natural conception, and the pregnancy was booked and supervised at a tertiary care center from 8 weeks of gestation. There were no significant antenatal complications. At 20 weeks of gestation, the antenatal ultrasonogram showed a triangular echogenic area in the left lung supplied by a feeding artery from the descending aorta. The heart was displaced to the right side. There was no evidence of pleural effusion or hydrops. The baby was delivered by an emergency lower segment cesarean section at 38 + 3 weeks of gestation in view of oligohydramnios and cord around the neck. The baby did not require active resuscitation. The birth weight of the neonate was 2700 g, which was appropriate for gestational age. The baby developed respiratory distress soon after birth. The respiratory rate was 72 breaths/min with mild subcostal retractions. There were no added sounds or decreased air entry. Oxygen saturation on room air was 84%. The baby was shifted to neonatal intensive care unit and started on oxygen by hood. General examination was normal, and there were no dysmorphic features present. The apex beat was felt in midclavicular line in the 4th intercostal space on the left side. No murmur was heard. In view of the antenatal imaging, X-ray chest was done which was apparently normal [Figure 1]. Computerized tomography (CT) angiogram of thorax revealed abnormal blood supply of posterior basal segment of left lower lobe arising from descending aorta with shunting into left pulmonary vein and further to left atrium. The feeding vessel was abnormally large and was almost half of the diameter of the aorta [Figure 2a]. There was a small area of collapse-consolidation in the posterior basal segment [Figure 2b]. Echocardiogram revealed a 3 mm-sized patent foramen ovale. Neurosonogram and ultrasound of abdomen were normal.

Figure 1

The chest X-ray

Figure 2

(a) Computerized tomography angiogram of thorax showing abnormal blood supply of posterior basal segment of left lower lobe arising from descending aorta with shunting into left pulmonary vein and further to left atrium (arrow), (b) computerized tomography showing adjacent small area of collapse-consolidation in the posterior basal segment

The baby was planned for thoracotomy and left lower lobectomy under general anesthesia with tracheal intubation. Left posterolateral thoracotomy was done through the 5th intercostal space. Thoracotomy revealed a nonventilated sequestrated segment in left lower lobe. Sequestrated segment was supplied by a large aberrant arterial feeder arising from below the diaphragm [Figure 3]. Aberrant artery was dissected carefully, doubly ligated and divided. Lower lobe branches of left pulmonary artery were individually dissected, doubly ligated and divided. Left inferior pulmonary vein was dissected, doubly ligated and divided. Left lower lobe bronchus was clamped, divided, and closed with 4-0 prolene, interrupted sutures. Left upper lobe was healthy. The baby required mechanical ventilation for 12 h postsurgery and was extubated on postoperative day 1. The baby was discharged on the 7th postoperative day in stable condition. Histopathology revealed findings consistent with lung sequestration. The baby has been followed up till 6 months of age and is asymptomatic.

Figure 3

Intraoperative photograph showing sequestrated segment of lung supplied by a large aberrant arterial feeder arising from below the diaphragm (arrow)

DISCUSSION

Rokitansky and Rektorzic first described PS in 1861 as a malformation comprising dysplastic lung tissue with no normal communication with the tracheobronchial tree and with an anomalous systemic arterial supply.[2] It is classified into intralobar and extralobar PS depending on the presence of own pleural lining in malformed lung tissue. Intralobar sequestration (ILS) is an abnormal lung tissue within the normal pulmonary parenchyma without its own pleural covering. Extralobar sequestration (ELS) is the true accessory lung, with its own pleural cover. Intra PS accounts for 75% of cases. ELS is more common in males while ILS has no gender predilection.

Most of the ILSs are located on the left side in the medial and posterior basal lung segments. Associated congenital anomalies in ILS are uncommon and in ELS include congenital cystic adenoid malformation, diaphragmatic hernia, bronchogenic cysts, cardiovascular malformation, and gastrointestinal malformation. The clinical presentation in neonates may be asymptomatic or symptomatic. The symptomatic clinical presentation may be in the form of respiratory distress, congestive heart failure, or hydrops fetalis. Recurrent pulmonary infection and pulmonary hemorrhage from the bleeding of feeder vessels are important complications. The presentation in our case was in the form of respiratory distress which could be explained by combined effect of sequestrated lobe and high flow arteriovenous shunting in the sequestrated lobe which can subsequently increase the work of breathing due to congestion. Chest X-ray was apparently normal in the present case. In our case, antenatal imaging finding helped in the decision for computerized tomographic angiography for confirmation of diagnosis.

The systemic arterial supply in ILS is through the descending thoracic aorta (72%), as seen in the present case; abdominal aorta, celiac axis, or splenic artery (21%); intercostal artery (3.7%); and rarely through the subclavian, internal thoracic, and pericardiophrenic arteries.[34] Most venous drainage (95%) is through the pulmonary veins. In our case, the blood supply of the sequestration tissue was from a giant feeder vessel which was approximately half of the diameter of aorta. Such a large vessel should be carefully handled during surgery and should be ligated at the first. If left untreated, ILS with giant feeder vessel can present as near-fatal pulmonary hemorrhage.[567] Chest radiographs may show the presence of opacity or cystic lesions or may be normal which so was in our case. Therefore, CT should be considered in the cases with high index of suspicion. Computerized tomographic angiography is diagnostic. It helps in identification of mass, areas of consolidation, systemic arterial supply, and venous drainage. The gold standard for identifying PS is angiography as it confirms the anatomy, systemic supply, and the venous drainage.

Symptomatic PS should be managed with surgical lobectomy. Controversies remain about the management of asymptomatic condition. The decision of surgical versus conservative management in asymptomatic cases in resource-limited settings should be individualized. Factors such as feasibility of regular follow-up, access to pediatric surgical services, and neonatal intensive care unit (in case of complications such as infections and hemorrhage) should be assessed.

CONCLUSIONS

Antenatal diagnosis of congenital lung malformation helps in careful planning of perinatal care in such cases and also facilitates the early diagnosis and management. The feeding vessels should be ascertained a priority to better take care of its dissection and ligation and to avoid any complications.

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Conflicts of interest

There are no conflicts of interest.