Abstract 14050: A Giant Free-Floating Ball Thrombus or a Tiny Fibroelastoma: Which Causes Multiple Strokes?

Abstract

Background: Left atrial (LA) thrombus is not rare in patients with mitral valve stenosis, but in patients with nonvalvular atrial fibrillation on anticoagulation, the formation of a "ball thrombus" in the LA is uncommon. Case: A 73-year-old man with nonvalvular atrial fibrillation on eliquis presented with frequent syncope and slurred speech. .The appearance of the infarcts on brain MRI and involvement of different vascular territories suggests embolic phenomena as the cause. On transthoracic echo a large, highly mobile echo density in the left atrium was noted. Transesophageal echo revealed smoke in the left atrium and the left atrial appendage. A large round mobile echo density mass measuring 4.7 cm X 3.6 cm was seen in left atrium with no attachment to left atrium. A mobile round density measuring 0.7x0.7 cm was seen on the right coronary cusp. Absence of perfusion, no enhancement, and high signal intensity on T1 and T2 weighted images on cardiac MRI was suggestive organized clot in left atrium. Decision-making: Both masses were removed successfully. Pathology confirmed a large intact spherical organized clot from the LA and a small fibroelastoma attached to the aortic leaflet. Conclusion: This was a rare case of giant round-shaped left atrium thrombus, which occurred in a patient with nonvalvular atrial fibrillation on anticoagulation. An aortic fibroelastoma was also discovered by transesophegeal echo as another potential cause of stroke. The left atrial thrombus is thought to have developed from a small mural thrombus caused by prolonged blood stagnation, which gets rounded by the sculpting impact of multiple complex encounters with the atrial wall. This may then detach from the LAA and form a floating "ball thrombus.