Isolated Unilateral Absence of Pulmonary Artery: An Incidental Finding During Pre-Op Evaluation

Abstract

Isolated unilateral absence of pulmonary artery (IUAPA) is a rare vascular anomaly mainly affecting men. Clinical presentation may range from no symptoms to shortness of breath and frequent respiratory tract infections, adversely impacting the quality of life. Here we report a middle-aged asymptomatic male diagnosed with IUAPA on an elective preoperative examination. CASE PRESENTATION:We present a fifty-nine-year-old male with history of hypertension and rheumatoid arthritis who was admitted to the hospital for an elective tracheostomy and composite resection of recently diagnosed squamous cell carcinoma of the right tonsil. Apart from localized jaw pain and restriction of movements, patient denied any other symptoms, like shortness of breath, chest pain, palpitations, orthopnea, fatigue, snoring, chronic cough, and hemoptysis. Patient states he can climb flights of stairs and perform daily activities without any difficulty. Of note, he was also a competitive swimmer in college. Patient's preoperative revised cardiac risk index score was 0, indicating a 3.9% 30-day risk of death, myocardial infarction, or cardiac arrest. ARISCAT post-operative pulmonary complications score was 34, indicating an intermediate risk with 13.3% complications rate. Arozullah respiratory failure index was 11-19 points with a 1.8% risk of respiratory failure. Electrocardiography was unremarkable. Chest x-ray showed collapse of the right lung with shift of the cardiomediastinal silhouette and trachea to the right along with hyperinflated left hemithorax and prominent left pulmonary artery as seen in figure 1. CT chest revealed absence of the right pulmonary artery with compensatory enlargement of the main and left pulmonary artery and hyper expansion of the left lung as seen in figure 2. Patient has successfully undergone the surgery with no post-operative complications.DISCUSSION: With a prevalence of 0.0005%, IUAPA is a rare anomaly that could present as an incidental finding in asymptomatic adults. It should also be considered in the presence of recurrent respiratory infections, decreased exercise intolerance, hemoptysis, or pulmonary hypertension in the absence of other known causes [1]. Plain films show contracted lung with mediastinal and tracheal shift, hemidiaphragm elevation, absent hilar shadow and pulmonary vascular markings [2]. A CT or MR angiography of chest can establish the diagnosis. Cardiac catheterization should be reserved for recurrent hemoptysis for embolization or during consideration of revascularization surgery [3].CONCLUSIONS: Despite being an alarming finding, asymptomatic IUAPA in adulthood should simply be watched carefully and shouldn't be a hindrance for undergoing surgical interventions. However, educating patients on potential adverse events, like hemoptysis, can help them to seek medical attention faster and thereby possibly prevent poor or even fatal outcomes.