PULMONARY EMBOLISM IN FONTAN CIRCULATION: A DIAGNOSTIC CHALLENGE

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Vascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: The population with congenital heart disease as well as Fontan physiology are rapidly growing as life expectancy is increased and better diagnostic and treatment approaches become available to those affected. The altered hemodynamics poses difficulties in the diagnosis of pulmonary embolism (PE) as computed tomography angiography (CTA) can be a suboptimal imaging and result in a nondiagnostic test. Thus, the risk factors and clinical presentation have an increased role when considering PE in this population. CASE PRESENTATION: A 26-year-old female with medical history of single ventricle and pulmonary atresia status post Fontan procedure was transferred to the intensive care unit (ICU) after an emergent cesarean section for close monitoring of hypoxemic respiratory failure and arrhythmia on telemetry. Before parturition the patient had developed sudden worsening of chest pain, shortness of breath, diaphoresis, supraventricular tachycardia of more than 160 bpm and hypoxemia. Upon arrival at ICU, laboratories revealed an elevated alveolar-arterial gradient, transaminitis, thrombocytopenia and hypermagnesemia. On evaluation of the electrocardiogram, Multifocal Atrial Tachycardia (MAT) was found. In ICU the patient had a transient intermittent arrhythmia that converted to wandering pacemaker for two days. Hypoxemia as a result of an arrhythmogenic event, coupled with structural heart disease and risk factors for a thromboembolic event, merited ruling out life threatening conditions. A CTA was performed but it could not confirm or rule out Pulmonary embolism (PE) due to aberrant anatomy of the myocardium. A Ventilation-Perfusion lung scan was obtained afterwards, demarcating a high probability for PE. Full dose anticoagulation with low molecular weight heparin was initiated obtaining an improvement in symptoms over the next two days. DISCUSSION: In this case, Fontan surgery resulted in a complex cardiopulmonary anatomy which made confirming PE diagnosis a challenge. CTA was unable to reveal the cause and false positive ventilation perfusion scanning results for PE in Fontan circulation has been reported. However, this patient’s pregnancy, decreased mobility, refusal of anticoagulation, and Fontan Circulation increased the risk for a thromboembolic event. Furthermore, such a patient presenting with chest pain, MAT and hypoxemia made PE a very likely diagnosis and the decision to start anticoagulation was made. CONCLUSIONS: Congenital heart disease poses clinical challenges during adulthood. This case underlines the importance of taking into account risk factors and clinical presentation in a setting where standard imaging protocols may be undiagnostic. In addition, case reports of pulmonary embolism in the Fontan circulation population state the need of optimization of alternative imaging protocols in order to improve diagnosis and for it not to be a challenge in the future. Reference #1: Beachey J, Widmer RJ, Jentzer J. Evaluating Pulmonary Embolism In Patients With Fontan Physiology. Journal of the American College of Cardiology. 2018;71(11). doi:10.1016/s0735-1097(18)33050-x. Reference #2: Panagiotidis E. False Positive Perfusion/Ventilation SPECT Study for Pulmonary Embolism in a Patient with Fontan Circulation. Malecular Imaging and Radionuclide Therapy. 2017;26(3):131-134. doi:10.4274/mirt.70883. DISCLOSURES: No relevant relationships by Sergio Alegre-Boschetti, source=Web Response No relevant relationships by Ian Da Silva Lugo, source=Web Response No relevant relationships by Gabriel Galindez De Jesus, source=Web Response No relevant relationships by Juan Santiago, source=Web Response No relevant relationships by Mark Vergara-Gomez, source=Web Response