Introduction
Pulmonary arteriovenous malformations are the atypical vascular communications between pulmonary arteries and veins that bypass capillary beds owing to low resistance, resulting in significant intrapulmonary right-to-left shunts. Reference Majumdar and McWilliams1 More than 70% of pulmonary arteriovenous malformation are associated with hereditary haemorrhagic telangiectasia, also known as Osler–Weber–Rendu syndrome. Reference Saboo2 Pulmonary arteriovenous malformations are classified as simple if there is one feeding artery and complex if there are two or more feeding arteries. Reference White, Pollak and Wirth3 Surgery was the standard treatment before the emergence of interventional procedures. Percutaneous transcatheter closure is currently the treatment of choice, whereas surgical treatment is limited to cases where transcatheter closure cannot be achieved. Reference Nagano4 In this case, we present a child with a complex pulmonary arteriovenous malformation with four feeding vessels and successful transcatheter closure with various devices.
Case report
A 4-year-old boy weighing 20 kg was referred to our clinic because of low oxygen saturation. He was incidentally found to have low arterial saturation at the time of his emergency department admission for vomiting. Physical examination was normal except mild cyanosis. Arterial oxygen saturation values were ranging from 72 to 86% at rest. Chest X-ray showed a homogeneous mass in the right lower zone. Echocardiography revealed mild enlargement of the left ventricle. Contrast echocardiography performed with agitated saline from the right antecubital vein showed microbubbles in the left atrium after three cardiac cycles (Fig. 1A). Right heart catheterisation was performed. Selective right pulmonary artery angiography with a 5 Fr pigtail catheter revealed a large lobulated vascular sac in the right lower zone with at least three feeding arteries (Supplementary Video 1; Fig. 2A, asterisks).The most superiorly located feeding artery was first occluded with a 6x4 mm Amplatzer Ductal Occluder II via a 5 Fr Amplatzer delivery system. The feeding artery located centrally, which divided into three major branches, was occluded with a 10 mm Cera vascular plug (LifeTech Scientific Corporation) through a 7 Fr guiding catheter before branching. Post-occlusion arterial saturation rose from 72 to 91%. Then, an 8 mm Cera vascular plug was placed in the most inferior vessel through a 6 Fr Amplatzer delivery sheath. Selective right pulmonary angiogram performed after implantation of the three devices demonstrated the presence of another large feeding artery located superiorly (Fig. 2B). Eventually, it was occluded with a 6x6 mm Amplatzer Ductal Occluder II through a 5 Fr Amplatzer delivery sheath. Meanwhile, the patient’s saturation reached 98%. Post-implantation angiography demonstrated stable positions of the devices and complete lack of contrast transmission (Supplementary Video 2; Fig. 2C). Contrast echocardiography performed the following day showed that there was no significant microbubble transmission into the left atrium (Fig. 1B).
Contrast echocardiogram from the antecubital vein before and after the procedure. (a) complete opacification of the left atrium and left ventricle. (b) Occasional filling of the left atrium and left ventricle with bubbles. LA, left atrium; RA, right atrium.
Angiographic findings. (a) Selective right pulmonary arteriogram with large arteriovenous malformation involving the right lower lobe. Three larger feeding arteries (asterisks). (b) Angiogram after post-occlusion of three feeding arteries. (c) Post-implantation angiography.
Discussion
Most patients with pulmonary arteriovenous malformation are diagnosed in adulthood, while only 10% are initially diagnosed in childhood. Reference Gossage and Kanj5 Pulmonary arteriovenous malformations are seen in female patients twice as often. Reference Guttmacher, Marchuk and White6 Since serious complications like cerebral thrombo-embolism, brain abscess, and pulmonary haemorrhage may emerge, it is recommended to treat after diagnosis. Endovascular closure is currently the treatment of choice because it is less invasive than surgery and has low complication rates. Reference Nagano4 More than 70% of pulmonary arteriovenous malformations occur in patients with hereditary haemorrhagic telangiectasia. Although our patient has congenital pulmonary arteriovenous malformation, he has no other features of hereditary haemorrhagic telangiectasia. Patients are generally asymptomatic but can lead to significant morbidity (26-33%) and mortality (8-16%). Reference Gossage and Kanj5,Reference Swanson, Prakash and Stanson7 Symptoms related to pulmonary arteriovenous malformation usually develop after the fourth decade of life, with dyspnoea on exertion being the most common complaint. Reference Fuchizaki8 Our patient was asymptomatic and incidentally diagnosed after a routine saturation measurement in the emergency department. Pulmonary arteriovenous malformations are classified as simple and complex according to the feeding artery supply. Reference White, Pollak and Wirth3 Simple ones are more common (80%) and have a solitary feeding artery. Complex ones have multiple feeding arteries and can have multiple septations. Reference White9 Generally, transcatheter interventions aim to embolise the feeding artery. Differently, in a patient whose feeding artery was previously embolised with 31 coils, the vein of the pulmonary arteriovenous malformation was embolised via a transseptal approach in a different session due to recanalisation Reference White, Pollak and Wirth10 . In the literature, the use of four devices for the closure of pulmonary arteriovenous malformations is rarely reported. As far as we have reviewed in the literature, our case is the first pulmonary arteriovenous malformation patient with four large feeding arteries treated endovascularly. In a case report, four devices were used as in our case, but with the difference that only two feeding arteries were embolised. Reference Sulaiman, Vinayakumar and Bastian11
Conclusion
Though pulmonary arteriovenous malformations tend to be asymptomatic, symptoms and significant neurologic complications are common in patients with large feeding arteries. Therefore, they should be treated as early as possible after diagnosis.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S1047951125000575.
