Combined endovascular and surgical approaches to treat intralobar pulmonary sequestration: a case report

Abstract

Pulmonary sequestration is a congenital abnormality of a non-functional pulmonary mass with anomalous systemic arterial supply. Surgical resection is the gold standard treatment, but it carries a risk of life-threatening haemorrhage from accidental injury of the anomalous artery. Endovascular embolisation has been introduced as a safe alternative, but does not eliminate the possibility of symptom recurrence. We report a case of a 61-year old woman with intralobar pulmonary sequestration treated with a combination of endovascular coil embolisation and surgical resection.

Background

Pulmonary sequestration is a congenital abnormality of a non-functional pulmonary mass with anomalous systemic arterial supply. It was first described by Huber in 1877 and named by Prycy in 1946.¹ The estimated incidence is 0.15–1.8%, although its exact incidence remains uncertain due to the unknown prevalence of asymptomatic cases.² Pulmonary sequestration is classified into extralobar and intralobar, depending on the presence of a distinct pleural covering separating it from the normal lung parenchyma. Extralobar pulmonary sequestration is less common (16%) and usually diagnosed in infancy, while intralobar pulmonary sequestration is relatively more frequently seen (84%) but tends to cause symptoms after two years of age.² Its clinical presentations, including chest pain, cough, chest infection, haemoptysis and heart failure, and computed tomography (CT) appearances, such as a cystic lesion, solid mass and bronchiectatic changes, are variable.

Surgical resection via thoracotomy or video-assisted thoracoscopic surgery is the gold standard treatment for pulmonary sequestration. It is curative but carries a small risk of torrential haemorrhage from the accidental tearing of the systemic feeding artery. Endovascular embolisation has gained popularity since the first report of its role in the treatment of pulmonary sequestration in 1998.³ In addition to its role as an alternative treatment for small-sized pulmonary sequestration, it can be used preoperatively to reduce the risk of surgical resection.⁴

Case history

A 61-year old woman who had never smoked presented with a recurrent chest infection and haemoptysis. Her past medial history included sciatica and treated hyperthyroidism. CT showed a slightly irregular-shaped mass, measured 42×16×38mm, located medially within the right lower lobe (Fig 1a,b). The lesion had both fluid and solid components. It was supplied by a coeliac trunk branch, which had a tortuous pathway before terminating in several small branches. This partially necrotic mass was deemed most likely to represent a pulmonary sequestration.

Figure 1.

(a, b) Oblique coronal views of the computed tomography angiography showing the pulmonary sequestration (asterisk) and the feeding artery (solid arrow) from the coeliac trunk. (c, d) Digital subtraction angiogram showing the feeding artery arising from the coeliac trunk before (c) and after (d) coil embolisation.

The outcome of a multidisciplinary meeting was to use a combination of endovascular embolisation and surgical resection via small modified thoracotomy. The patient agreed with this plan and provided consent for publication of her case.

The embolisation was performed via a right femoral artery access using a 5-French catheter and coaxial 2.7-French microcatheter. A series of platinum detachable coils were placed into the feeding artery until stasis (Fig 1c,d). Two days later, surgical resection was performed. The feeding artery was found to be in the inferior pulmonary ligament and ligated using an Echelon 60-mm vascular stapler (Fig 2), followed by a standard right lower lobectomy.

Figure 2.

Intraoperative views showing the feeding artery before (a) and after (b) being ligated

The patient was discharged three days later. No complication was reported during her follow-up clinic eight weeks later. The pathology report confirmed an intralobar pulmonary sequestration surrounded by lung tissues with bronchiectatic changes, severe scarring and active inflammation.

Discussion

The combination of surgical resection and endovascular embolisation makes the management of pulmonary sequestration much safer. First, in our patient, endovascular embolisation reduced the danger of intraoperative profuse haemorrhage. One of the defining features of pulmonary sequestration is a systemic arterial supply, mainly from the descending aorta. Despite having to sustain systemic arterial pressure, these feeding arteries usually have fewer muscle fibres than normal arteries, making them more susceptible to tearing. Moreover, previous chronic inflammation in pulmonary sequestration and its surrounding lung parenchyma leads to the development of adhesions.⁴ Adhesiolysis during the operation increases the risk of accidental injury to the feeding arteries, especially in this case where the feeding artery divided into multiple branches in the right pleural space.

Second, the preoperative endovascular procedure helps confirm the diagnosis of pulmonary sequestration. According to one of the largest pulmonary sequestration studies published,¹ 58.6% of pulmonary sequestration were incorrectly diagnosed. The angiography performed during endovascular embolisation precisely delineates the anatomy of the systemic arteries, which is invaluable for operative planning, and confirms the lack of blood flow to the pulmonary sequestration after successful embolisation. In the 15–20% of patients with multiple anomalous arteries,⁴ the endovascular approach can embolise each individual feeding artery. In the rare cases where the feeding artery is aneurysmal, endovascular exclusion with a stented graft followed by surgical resection has a more favourable risk profile than surgical resection alone.⁵

Conclusion

We believe that the addition of endovascular embolisation made this surgical resection of pulmonary sequestration safer and easier to perform. This combined approach should be considered for all cases of pulmonary sequestration that warrant surgical resection.