Coil embolization to treat pulmonary sequestration in the right upper lobe

Although there have been a few case reports of pulmonary sequestration, it is primarily located in the lower lobe and left lung, rarely in the right upper lobe. Here, we report a case presented with haemoptysis. Computed tomography images revealed ﬂake ground-glass shadows in the right upper lobe. Computed tomography angiography demonstrated an artery supplied the affected lesions stemmed from the aortic arch. We diagnosed and treated her with bronchial artery angiography with coil embolization. No complications were found after operation until now. Thus, CTA could help identify the abnormal blood vessels, and interventional therapy may be an effective alternative to surgery of pulmonary sequestration.


INTRODUCTION
Pulmonary sequestration (PS) is a congenital lung malformation recognized by abnormal lung tissues separated from normal lung in embryonic development and fed by aberrant systematic arteries, which lack normal communication with bronchial trees. It accounts for 0.15-6.4% of all congenital pulmonary malformations, mostly located in the lower lobe (98%) and left lung (58%), rarely in the right upper lobe [1,2].
Interventional therapy has been increasingly used as an alternative to surgery in recent years. We report a case of PS in the right upper lobe presented with haemoptysis, which was successfully cured by coil embolization.

CASE PRESENTATION
A 50-year-old female patient complained of repeated haemoptysis over 3 months. Computed tomography angiography revealed flake ground-glass shadows in the right upper lobe that communicated with an aberrant artery stemmed from the aortic arch on multiplanar and three-dimensional reconstructions (diameter: 4-7 mm; Fig. 1). The partially flake ground-glass shadows were deemed most likely to represent the sequestered lung.
Treatment options, including surgical resection and bronchial artery angiography with coil embolization, were explained in full detail to the patient. She decided to proceed with interventional therapy. Access was gained through the right common femoral artery using a 5-French catheter and coaxial 2.5-French microcatheter. A series of spring coils were placed into the feeding artery until stasis (COOK, MWCE-TORNADO, 8 mm). Repeat angiogram demonstrates no perfusion of the PS (Fig. 2).
After coil embolization, the patient stopped haemoptysis and was discharged 3 days later. No complications were found during her follow-up of 4 weeks later. Computed tomography revealed the flake shadows in the right upper lobe were absorbed.

DISCUSSION
In 1947, Pryce [3] reported 7 cases of lung lesions directly supplied by arterial branches and separated from normal lung tissue, and named this disease as PS. PS consists of intralobar sequestration and extralobar sequestration. Asymptomatic extralobar sequestration accounts for about 25% of PS. Intralobar sequestration often presents with cough, fever, chest pain, recurrent pulmonary infections and haemoptysis, accounting for about 75% of PS [4].
Extralobar sequestration is usually fed by descending thoracic (72%), abdominal aorta (21%) and the intercostal arteries (3%) [5]. As the gold diagnostic standard of PS, digital subtraction angiography is an invasive technique with high-dose exposure to radiation. In contrast, computed tomography angiography offers a non-invasive way of displaying the origin and pathway of aberrant arteries. In this case, three-dimensional computed tomography reveals the feeding branch arises from the aortic arch, whose pressure is higher than normal pulmonary artery, making    Coil embolization is advantaged by microtrauma, short-term recovery and less postoperative complications. Interventional embolization aims to cause ischaemia, consolidation and even mechanization of the isolated pulmonary lobe by occluding the aberrant artery supply. Gelatine sponge, absolute ethanol, polyvinyl alcohol (PVA) particles and spring coils are available embolization materials. Gelatine sponge is cheap, but easily washed away by aberrant artery supply with large flow in a short time. PVA particles, spring coils are suitable for blood vessels requiring permanent embolization. For PS supplied by a single artery, simple coil embolization is enough. For PS supplied by multiple arteries, multiple embolization material can be used in combination according to clinical requirement.
Interventional therapy inevitably has some postoperative complications, including pulmonary infection, ectopic embolism, acute pulmonary embolism, etc. Acute pulmonary embolism should attract the most attention and needs first aid measures as it happens.
CONCLUSION PS is rarely located in the right upper lobe, manifesting as chest pain, haemoptysis and recurrent pulmonary infections.
Computed tomography angiography determines the origin, number and course of feeding arteries. Surgery is the standard treatment for complex cases. For patients who are complex cases and insist on intervention therapy, coil embolization might be effective for symptoms relives according to our short-term follow-up result.