LEFT ATRIAL THROMBUS IN THE ABSENCE OF RISK FACTORS

Abstract

SESSION TITLE: Medical Student/Resident Cardiovascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Left atrial thrombus is commonly seen in conditions such as atrial fibrillation, rheumatic mitral stenosis, and conditions of hypercoagulability. The cause of left atrial thrombus in the absence of these conditions is not clear. This is a case of a 59-year-old female who presented with emboli to her spleen, brain, and bilateral lower extremities. The patient was found to have a highly mobile thrombus attached to the posterior wall of the left atrium. She did not have atrial fibrillation, a history of clotting disorder, or significant mitral dysfunction and was up-to-date on all age appropriate cancer screenings. CASE PRESENTATION: A 59-year-old female presented with confusion and right arm weakness. Her past medical history is significant only for mitral valve repair which was done with minimally invasive annuloplasty 18 months prior. She was found to have an MCA stroke which was treated with emergent thrombectomy. Further workup revealed a 1.1 cm x 1.4 cm irregular, highly mobile mass attached to the posterior wall of the left atrium. One month prior the patient was found to have a splenic infarct and on re-inspection of the TTE done at that time, a much smaller thrombus was detected in the same location which was previously missed. Her TEE revealed mild mitral regurgitation and an EF of 20-25%-- down from 55-65% one month prior; this along with apical ballooning was suggestive of Takotsubo cardiomyopathy. Bilateral lower extremity Doppler found thrombi in both popliteal arteries. Her hypercoagulability work-up was completely negative and she was up-to-date on all age appropriate cancer screenings. The patient was discharged on apixaban for long-term anticoagulation after stabilization following her stroke with no residual deficits. DISCUSSION: The etiology of this patient’s left atrial thrombus remained unclear despite hypercoagulability testing, cancer screening, continuous telemetry, and a thirty-day event monitor. This presents a diagnostic and management challenge. Cardiac valve surgeries can be complicated by valvular thrombi. However, prosthetic annuloplasty rings, as seen in this patient, are less likely to cause thrombosis compared to prosthetic valves, especially so long after the procedure [1]. Moreover, the thrombus was not attached onto any part of the valve or prosthesis. Occult malignancy was also a concern, being a strong risk factor of arterial thromboembolism [2]. However, there was no objective evidence of malignancy and her screening was all up-to-date. Finally, given the unknown etiology of the thromboembolism there was very little guidance on the best anticoagulant to use. Apixaban was used eventually mostly due to patient preference and extrapolation from atrial fibrillation patients. CONCLUSIONS: Left atrial thrombus in the absence of several classic conditions presents a diagnostic and therapeutic challenge. Reference #1: 1. Nishimura R.A., Otto C.M., Bonow R.O., et al. 2014 AHA/ACC Guideline for the Management of Patients with Valvular Heart Disease: Executive Summary. Circulation: Journal of the American Heart Association, 129(1), 2440-2492. doi:10.1161 Reference #2: 2. Navi B.B., Reiner A.S., Kamel H., et al. (2019). Arterial thromboembolic events preceding the diagnosis of cancer in older persons. Blood, 133(8), 781. doi:10.1182 DISCLOSURES: No relevant relationships by Anat Bergner, source=Web Response No relevant relationships by Hadas Michaeli, source=Web Response No relevant relationships by Nino Nozadze, source=Web Response No relevant relationships by Curtis Xu, source=Web Response