B64-25 Trapped in Transit: A Case of Right Atrial Thrombus With Bilateral Pulmonary Embolism

Abstract Pulmonary embolism (PE) is a well-recognized and potentially fatal condition. PE typically results from thromboembolic migration from the venous system, most often from the lower extremities to the pulmonary arteries. A rarer but clinically significant source is the right atrial thrombus, which carries the risk of immediate embolization and sudden hemodynamic collapse. This is the case of an 88-year-old female with a history of congestive heart failure, atrial fibrillation post-Watchman device and pacemaker/defibrillator (off anticoagulation), chronic kidney disease, and hypothyroidism who presented with three days of dyspnea on exertion. She was hemodynamically stable upon arrival, and her labs were significant for a proBNP level of 8723 and a D-dimer level of 8363. CT pulmonary angiogram was significant for bilateral pulmonary thromboembolism with proximal extent into the distal main pulmonary arteries and findings suggestive of right heart strain. A filling defect in the markedly dilated right atrium raised concern for intracardiac thrombus. She was placed on oxygen, started on heparin drip, and admitted to the medical ICU. Transthoracic echocardiogram (TTE) showed a severely dilated right atrium containing a large mobile thrombus measuring 8.2 cm, a mildly dilated right ventricle, and TAPSE 1.0 cm. On hospital day two, she underwent right atrial thrombectomy with retrieval of three large intra-atrial thrombus segments (7cm, 6cm, and 3cm). Thrombectomy of pulmonary embolism was deferred given the risk of dislodging residual atrial thrombus. Repeat TTE showed a smaller 1.1 cm RA thrombus with possible adherence to pacer wire, improved TAPSE of 1.5 cm, and persistent atrial dilation. The patient was transitioned to abixaban from heparin drip and remained stable. She was ultimately downgraded from the ICU. Mobile right atrial thrombus is a rare and under-diagnosed cause of PE with increased mortality. This case emphasizes the role of bedside echocardiography in early diagnosis and thrombectomy in managing massive clot burden. In high-risk elderly patients, rapid diagnosis and prompt coordination among the intensivist, cardiology, and interventionalist teams can be lifesaving. This abstract is funded by: None