Discussion

Alternative sources of pulmonary blood supply should be considered in a patient with a dilated left heart without an alternative aetiology.Reference Hubail, Eapen and Lemler ¹

Pulmonary sequestration is a rare congenital lung malformation, with an estimated incidence of 0.15–1.8% and a male to female predominance of 1.58:1.Reference Wei and Li ² In intralobar sequestration, the arterial supply is derived from the thoracic aorta and venous drainage occurs through the pulmonary veins with resultant left-to-left shunt. Symptomatic patients often present with chronic cough, fever, haemoptysis, chest pain, or shortness of breath. Rarely, they present with evidence of congestive heart failure secondary to excessive blood flow through the sequestered lobe.Reference Levine, Nudel and Gootman ³

Extralobar sequestrations are generally asymptomatic and are often incidentally diagnosed. The venous drainage is usually via the inferior caval vein, portal venous system, or azygous vein, resulting in a left-to-right shunt. Extralobar sequestrations have been associated with CHD including truncus arteriosus, total anomalous pulmonary venous return, pulmonary atresia with ventricular septal defect, and dextrocardia.Reference Wei and Li ^{2 ,} Reference Nakata, Ikeda and Doi ⁴

Sequestration most commonly occurs in the left lower lobe. The majority of sequestered lung segments are supplied by a single artery with greater than two feeding arteries seen <5% of the time.Reference Wei and Li ^{2 ,} Reference Nakata, Ikeda and Doi ⁴ To our knowledge, there is only one other case report of pulmonary sequestration with triple arterial supply and venous drainage via the pulmonary veins and the inferior caval vein.Reference Theodoropoulos and Schwartz ⁵ Classically, sequestered lung segments have been resected via thoracotomy or with thorascopic surgery. There are multiple reports of use of transcatheter embolisation of systemic arterial supply of sequestered lung segments using embolisation coils and devices, microcoils, particles, absolute alcohol, or histoacryl.Reference Castaldi, Santoro and Gaio ^{6 –} Reference Curros, Chigot and Emond ¹⁰ Early complications in a small number of patients from the procedure have included transient ischaemic limb changes, sepsis, and renal abscess in one patient from thrombus.Reference Leoncini, Rossi and Ferro ^{8 ,} Reference Curros, Chigot and Emond ¹⁰

Most devices used for successful embolisation of pulmonary sequestrations require a long sheath or guide catheter for delivery.Reference Castaldi, Santoro and Gaio ^{6 –} Reference Curros, Chigot and Emond ¹⁰ The feasibility of utilising the delivery long sheaths or guide catheters can be limited in tortuous vessels. The technical difficulties can lead to prolonged procedure times, increased radiation dose, incomplete occlusion, or limit the patient population for which interventional approach is suitable. A recent addition to our device armamentarium is the St. Jude Medical Amplatzer Vascular Plug 4 that can be delivered via any 0.038″ guide wire-compatible catheter. This is a major advantage over other devices, as Amplatzer Vascular Plug 4 devices can be delivered through the same flexible catheters used to achieve access into the feeding vessels and perform selective angiography, obviating the need for exchanging to a long sheath or guide catheter. There is only one other case report of utilising an Amplatzer Vascular Plug 4 for embolisation for lung sequestration.Reference Castaldi, Santoro and Gaio ⁶ We used six devices for closure of multiple feeding branches to achieve complete occlusion of the sequestered lung segments. The Amplatzer Vascular Plug 4 proved useful as this device was easily advanced to distal tortuous sites not amenable to long sheath placement. In addition, this device offered the advantage of a controlled release, unlike standard embolisation coils that go through the same catheters, making embolisation of the device less likely.