Proximal Interruption of the Pulmonary Artery: A Case Series

Abstract

A seven-year-old boy, presented with recurrent respiratory tract infection. The chest radiograph showed reduced left lung volume, small left hilum, and hyperlucent contralateral lung herniated across the midline. A diagnosis of left pulmonary hypoplasia was considered initially. Contrast CT thorax confirmed volume loss in the left haemithorax with hyperinflation of the right lung [Table/ Fig-1b]. There was non-visualization of the entire left pulmonary artery , with paucity of pulmonary vasculature, mild bronchiectasis, subpleural and mediastinal systemic collaterals, pleural thickening and subpleural scarring . The patient underwent pneumonectomy and the gross specimen showed hypoplastic, pale looking left lung with a leash of telangiectatic vessels and absent left pulmonary artery. Microscopy revealed mild bronchiectasis and interstitial inflammation within the hypoplastic lung. Case 2A 27-year-old male patient, with an underlying congenital heart disease (subaortic VSD, mild aortic regurgitation and mild mitral regurgitation) diagnosed on echocardiography, presented with haemoptysis of 3 months duration. Chest radiograph showed loss of right lung volume, with paucity of markings. There were linear opacities and pleural thickening in the right upper zone. The left lung showed increased transradiancy and hyperinflation, with prominence of the left hilum. Contrast enhanced CT thorax We present a few cases of Proximal Interruption of the Pulmonary Artery, an uncommon developmental anomaly associated with congenital heart disease. The cases had varied clinical presentations. Chest radiograph showed a hypoplastic lung with an ipsilateral small hilum on the side of the interruption and hyperinflation of the contralateral lung. Contrast CT confirmed the diagnosis, demonstrating non-visualization of the left or right pulmonary artery, and other related findings.demonstrated loss of right lung volume, non-visualization of the right pulmonary artery and its branches, and collaterals from bronchial and non-bronchial systemic circulation in the subpleural and intercostal spaces [Table/ Fig-2b]. There were discrepancies in the calibre of the intraparenchymal pulmonary arterial branches in the right and left lungs. Right pleural thickening and parenchymal scarring were present. AFB smear was negative and sputum culture showed multiple gram-positive bacteria. The patient was treated with antibiotics and had no haemoptysis at first follow up. He was advised embolization, if haemoptysis recurred. Case 3A 57-year-old male patient, diagnosed elsewhere to have non-small cell carcinoma lung, came for a follow up CT after chemotherapy.

Mimickers of chronic thromboembolic pulmonary hypertension on imaging tests: a review

“…Left-sided interruption of the pulmonary artery is often associated with concurrent congenital cardiac anomalies like tetralogy of Fallot, right aortic arch, aortic coarctation, patent ductus arteriosus, septal defects, and transposition of great arteries. [81][82][83] Right-sided defects are usually present in isolation. 18 The affected lung is supplied by systemic collateral vessels formed mainly by branches of the bronchial arteries but also by collaterals from the intercostal, internal mammary, subclavian, subdiaphragmatic, or innominate arteries.…”

“…18 The affected lung is supplied by systemic collateral vessels formed mainly by branches of the bronchial arteries but also by collaterals from the intercostal, internal mammary, subclavian, subdiaphragmatic, or innominate arteries. 80,81,83 This condition is typically diagnosed at a younger age (median age of 14 years). 83 The most common symptoms include recurrent infections, dyspnea, exercise intolerance, and hemoptysis.…”

“…80,81,83 This condition is typically diagnosed at a younger age (median age of 14 years). 83 The most common symptoms include recurrent infections, dyspnea, exercise intolerance, and hemoptysis. 80,83 In a significant proportion of adult patients, this condition can be asymptomatic.…”

“…The CTA will also show the collateral vessels on the affected side of the lung and ipsilateral volume loss. 83 If a main pulmonary artery is blocked by a thrombus in CTEPH, it may mimic UPPA on a CTA and be difficult to distinguish from this condition. A VQ scan may not be reliable in distinguishing UPPA and CTEPH as both conditions will show mismatched perfusion defects.…”

“…87 However, in UPPA, the perfusion defect will only be seen on one side. 83 Cardiac MRI may be useful in identifying other congenital anomalies of the cardiac structures that may be present concomitantly. 80 A history of deep vein thrombosis may provide a clue to the presence of CTEPH.…”