Isolated MAPCAs – A rare cause of hemoptysis in an adolescent

Dear Editor,

A previously healthy 15-year-old female presented to respiratory medicine with complaints of sudden onset haemoptysis (3–4 episodes) and shortness of breath. She had no history of similar complaints in the past, nor of fever or cough. General and systemic examination was unremarkable. Initial blood investigations revealed mild leucocytosis. Chest Xray showed homogenous opacification of the left lower lung lobe. Hence, suspecting pneumonia, intravenous antibiotics were started. However, her symptoms persisted. Bronchoscopy and bronchoalveolar lavage were non-contributary. She was referred to paediatric cardiology. Her 2D echocardiography showed dilated left atrium and left ventricle, and retrograde flow in left pulmonary artery (LPA).

CT pulmonary angiography was performed for better delineation [Video 1]. It showed dilated LPA with abnormal branches to the lower lobe of left lung. Left upper pulmonary vein was absent. In addition, dilated tortuous left bronchial arteries were seen arising from the descending thoracic aorta at D5, D6, and D7 level and coursing toward the left upper lobe, left lingula and left lower lobe.

During cardiac catheterization, PA pressure was noted to be normal (34/17/28 mmHg, aortic pressure 113/60/83 mmHg). Angiogram of branch pulmonary arteries, using multipurpose A2 catheter, showed competitive flow into LPA and normal flow in RPA. No pulmonary arteriovenous malformation was seen. Aortogram using pigtail catheter showed significant collaterals from the descending aorta; which were subsequently hooked using right coronary catheter. Collaterals from descending thoracic aorta (DThA) and left subclavian artery (LSCA) were seen forming a vascular malformation and draining into LPA. These were closed using Cook coils and Amplatzer Vascular Plug II. Collaterals to left lung from DThA and LSCA to the left lung were also closed using AVP II and Lifetech vascular plug [Video 2]. Right subclavian artery angiogram was normal.

There was significant reduction in the blood flow of collaterals after coiling and device closure. Patient’s hemoptysis resolved and she was discharged in a hemodynamically stable condition.

On 18 months follow-up, she remains asymptomatic.

EMBRYOLOGY

In the early fatal life, primitive intersegmental arteries supply the lung parenchyma prior to the formation of the pulmonary arteries. As the PAs develop, the intersegmental arteries regress and cease to supply the lungs by 50 days post ovulation. However, they may continue to supply the lungs in case of restricted pulmonary circulation caused by anomalies of right ventricular outflow tract, pulmonary valve, or pulmonary artery.[1]

Isolated collaterals that persist without underlying heart disease are rare but have been described in the literature. They are associated with prematurity, neonatal hypoxic/ischemic episodes, traumatic conditions, and ingestion of maternal antiepileptic drugs.[2]

CLINICAL PRESENTATION

Isolated MAPCAs are usually seen in the newborn period or childhood. Commonly asymptomatic, they also close spontaneously. Hence, they seldom require treatment. However, rarely they may present with recurrent respiratory tract infections, congestive heart failure, incidental detection by murmur, or hemoptysis.[3,4,5]

Our patient presented much later than what has been reported in literature. Hemoptysis occurs either due to the rupture of the collateral or subsequent development of pulmonary hypertension. In addition, collateral arteries act as peripheral left to right shunt, which led to her left atrium and ventricle being dilated on echocardiography.

MANAGEMENT

Echocardiography, CT angiogram, and MRI have key roles in diagnosis, with echocardiography being the primary imaging modality. But even a chest radiograph can provide an important clue due to the differential pulmonary vascularity. In our patient, the chest radiography showed homogenous opacification, which was erroneously thought to be pneumonia.

Cardiac catheterization is the gold standard, being both diagnostic and therapeutic. Angiography delineates the anatomy of the collaterals, their arborization pattern, the pulmonary territory they supply, communication with the branch pulmonary artery, associated stenosis, and for planning endovascular embolization.[1] Patent non-stenotic collaterals transmit increased blood volume, as well as high systemic pressures to the normally low-pressure pulmonary circulation. Hence, closure of these collaterals is warranted, especially in symptomatic patients, to prevent microvascular changes in the lung parenchyma.

In our patient, pulmonary artery angiogram showed competitive flow into the left pulmonary artery, suggestive of presence of collaterals. In addition, significant collaterals were seen arising from the descending aorta and the left subclavian artery and draining into the left pulmonary artery, which were subsequently closed. Coils are commonly used for the closure of major aortopulmonary collateral arteries, but due to the significant size, we also used vascular plugs.

Our case is unique as she presented outside the common age group, with sole complaints of haemoptysis. A thorough and segmental echocardiographic evaluation helped in clinching the diagnosis. In addition, timely intervention had good results.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.