Abstract 15986: Very Rare Case of a Interatrial Thrombus Following Watchman Device Placement

Abstract

Introduction: Device related thrombus (DRT) is a known complication of left atrial appendage closure (LAAC). We present a case of a thrombus at the interatrial septum following LAAC detected eight months after the procedure. Case: Eighty-six years old woman with a history of coronary artery disease s/p percutaneous coronary intervention with drug eluting stent to right coronary artery in 2016, heart failure with preserved ejection fraction, atrial fibrillation (AF) s/p 27mm Watchman device placement (on aspirin only) due to recurrent episodes of hematuria, hypertension, hyperlipidemia, chronic kidney disease presented to the hospital with complaints of right flank pain. Initial labs were unremarkable except for anemia, hemoglobin of 10g/dl. Computed tomography (CT) abdomen and pelvis showed an incidental finding of new mass like filling defect within the left atrium. Transthoracic echocardiogram (TTE) showed mobile mass 1.7 x 1.6 cm attached to the interatrial septum on the left atrial side.(Figure 1.A) Low dose apixaban was started. Follow up transesophageal echocardiogram (TEE) in four months interval showed the thrombus attached to the interatrial septum had slightly reduced in size to 1.5 x 0.9 cm, but an additional large thrombus measuring 2.5 x 1.3 cm was seen on top of the Watchman device (Figure 1.B) and Apixaban was increased to full dose. Discussion: Incidence of DRT after LAAC is 3.74% with most cases occurring in the first year after LAAC. Exposed and incompletely endothelialized device are foci for DRT. Iatrogenic pericardial effusion, hypercoagulable state, deep implant, renal insufficiency, non-paroxysmal AF are some of the factors increasing the risk of device related thrombus. Most cases of DRT described are attached to the device. In our case, a large interatrial thrombus was identified incidentally which likely formed at the site of septal puncture during device insertion which highlights the importance of follow up echocardiogram at intervals.