Mixing artifact on imaging misinterpreted as pulmonary embolism in adult congenital heart disease patient with hemoptysis

SESSION TITLE: Broken Hearts SESSION TYPE: Case Reports PRESENTED ON: 10/09/2023 01:00 pm - 02:00 pm INTRODUCTION: Congenital heart disease (CHD) accounts for 1% of all births in the United States, and with advances in management, adults with complex cardiac anatomy are more frequently being admitted to adult critical care units. (1) CHD patients have complex anatomy with unique complications of which providers should be aware. Tricuspid atresia is a form of cyanotic CHD in which the tricuspid valve does not develop in utero resulting in the absence of a passage between the right atrium and right ventricle. Cavo-pulmonary anastomosis, a procedure in which the vena cava is connected directly to the pulmonary artery, has greatly improved survival of patients with tricuspid atresia. (2) A common sequela of this procedure is the formation of pulmonary arteriovenous malformations (AVMs). (3) Here we present a case of hemoptysis, hypoxia, and a pulmonary artery mixing artifact masquerading as a pulmonary embolus in a patient with cavo-pulmonary anastomosis and pulmonary AVMs. CASE PRESENTATION: A 27-year-old male presented to an emergency department with small volume hemoptysis for two days. The patient was found to have an oxygen saturation of 80% on room air. Vitals were otherwise unremarkable. On exam, he appeared comfortable. Lungs were clear to auscultation. Marked digital clubbing was noted as well as a hemoglobin of 20.8 mg/dL. CT angiogram of the chest demonstrated a large hypodensity in the main pulmonary artery concerning for a pulmonary embolus. The patient was started on a heparin infusion and transported to our hospital. The patient required high flow nasal cannula to maintain oxygen saturations above 90%. Further review of the imaging revealed tricuspid atresia with single ventricle physiology and a prior surgical cavo-pulmonary anastomosis. The suspected pulmonary embolus was rather a venous-arterial mixing artifact in the main pulmonary artery. The heparin was discontinued and oxygen saturation goals were reduced to 80-85%. The patient was weaned to room air without event. Bronchoscopy showed bleeding in the basal segment of the right lower lobe which corresponded to an AVM. Embolization of feeding arteries was performed with resolution of hemoptysis. The patient was seen by adult congenital cardiology in-house, and follow-up was arranged prior to discharge. DISCUSSION: Complex CHD anatomy can produce mixing artifact on imaging studies that may resemble filling defects. In this case of hemoptysis, tricuspid atresia with cavo-pulmonary anastomosis (Glenn procedure) produced a mixing artifact that, in the context of profound hypoxia, was misinterpreted as a pulmonary embolism resulting in the incorrect and potentially harmful initiation of anticoagulation. Pulmonary AVMs are frequently seen after the Glenn procedure and can present as hemoptysis. (3) CONCLUSIONS: As the CHD population's life expectancy continues to increase, providers should become familiar with common CHD anatomy and potential post-repair complications. REFERENCE #1: Hendrickson M, Arora S, Chew C, et al. EIGHTEEN-YEAR TRENDS IN HOSPITAL ADMISSIONS FOR ADULTS WITH CONGENITAL HEART DISEASE. J Am Coll Cardiol. 2021 May, 77 (18_Supplement_1) 448. https://doi.org/10.1016/S0735-1097(21)01807-6 REFERENCE #2: Minocha PK, Phoon C. Tricuspid Atresia. [Updated 2022 Sep 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554495/ REFERENCE #3: Duncan BW, Desai S. Pulmonary arteriovenous malformations after Cavopulmonary Anastomosis. The Annals of Thoracic Surgery. 2003;76(5):1759-1766. doi:10.1016/s0003-4975(03)00450-8 DISCLOSURES: No relevant relationships by Ibett Colina Garcia No relevant relationships by Abigail Khan No relevant relationships by Miranda Merrill No relevant relationships by Lucas Meuchel No relevant relationships by Craig Morris No relevant relationships by Bart Moulton No relevant relationships by Mason Paas No relevant relationships by Vishal Saini