ISOLATED CONGENITAL ABSENCE OF THE LEFT PULMONARY ARTERY WITH LUNG HYPOPLASIA

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Vascular Disease 1 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Unilateral absence of the pulmonary artery (UAPA) is a rare congenital defect with significant physiologic sequelae. Here, we describe a patient presenting with congenital isolated left-sided UAPA. CASE PRESENTATION: A 27-year-old African male presented with six weeks of flu-like symptoms. He was born in Sierra Leone and immigrated to the United States at age 17. To evaluate his persistent cough and left side chest discomfort, a chest x-ray was obtained, showing significant opacification of the left hemithorax with left pneumothorax initially concerning for necrotizing pneumonia. He was placed on broad spectrum IV antibiotics and admitted. A follow-up computerized tomography of the chest found significant hypoplasia of the left lung with changes consistent with chronic infection, a significantly hypoplastic left pulmonary artery (PA), and hyperexpanded right lung. An echocardiogram found the right PA to be 1.8 cm in diameter compared to the left PA at 1.1 cm. His antibiotic regimen was changed to Augmentin to cover community-acquired pneumonia and he was discharged with plan to follow up with Cardiothoracic Surgery. DISCUSSION: UAPA is a rare condition that typically presents with associated congenital heart defects. Isolated presentation is even rarer, especially on the left side. During embryogenesis, the extrapulmonary PAs arise from the sixth aortic arch. Improper development, possibly due to persistence of a ductus arteriosus, leads to agenesis of the ipsilateral PA. While revascularization from collateral circulation arising from other arteries is possible, typically, inadequate blood flow to the ipsilateral lung during fetal development leads to hypoplasia of the lung.A UAPA essentially cuts pulmonary circulation in half, resulting in a diversion of cardiac output to the remaining PA. Studies in pigs have shown medial hypertrophy of the larger PAs in the unaffected lung and increased muscularity of the smaller arteries. Pulmonary hypertension developed in 44% of all patients with associated right ventricular hypertrophy. This can ultimately lead to right heart failure and eventually death.While many present in infancy, it is not uncommon for patients to remain asymptomatic until adulthood, when they may present with dyspnea on exertion, hemoptysis, or recurrent pulmonary infections. Patients often have a hypertrophied contralateral lung to compensate for the hypoplastic affected lung, leading to a mediastinal shift towards the affected lung. Despite this compensation, patients often have decreased pulmonary function. CONCLUSIONS: Isolated left UAPA results in left lung hypoplasia secondary to lack of blood flow during development. The diversion of cardiac output through the remaining PA may result in pulmonary hypertension and right-side heart failure. Pulmonary function is usually decreased despite contralateral lung compensation. Reference #1: Steiropoulos P. Unilateral pulmonary artery agenesis: a case series. Hippokratia. 2013;17(1):73–6. Reference #2: ADJ TH, NA B, Ottenkamp J. Isolated unilateral absence of a pulmonary artery: a case report and review of the literature. Chest. 2002;122(4):1471–7. Reference #3: Kruzliak P, Syamasundar RP, Novak M, Pechanova O, Kovacova G. Unilateral absence of pulmonary artery: Pathophysiology, symptoms, diagnosis and current treatment. Arch Cardiovasc Dis. 2013;106:448–54. DISCLOSURES: My spouse/partner as a Employee relationship with SAS Please note: >$100000 Added 02/28/2018 by Audrey Hopping, source=Web Response, value=Salary No relevant relationships by Vikas Pathak, source=Web Response No relevant relationships by Christine Zhou, source=Web Response