Abstract 16233: Paradoxical Coronary Embolus Associated With Right Atrial Thrombus in Cardiac Amyloidosis

Abstract

Introduction: This case highlights amyloidosis’ risk for intracardiac thrombosis with an atypical presentation of paradoxical coronary embolism due to right atrial thrombus. Clinical Presentation: An 87-year-old male with atrial fibrillation not on anticoagulation, HFrEF, severe mitral regurgitation, CKD3B, and recent medically managed NSTEMI, presented with shortness of breath. Labs showed elevated Troponin-T HS (174 ng/L) and proBNP (11,955 pg/mL). Echocardiogram revealed EF 25-30% with new lateral and anterior wall akinesis, concerning for NSTEMI I. Coronary catheterization revealed possible thrombus in the left circumflex artery (Figure 1A), but distal perfusion was intact. CT angiogram was negative for coronary artery dissection, providing clearance to initiate treatment with Eliquis. Intriguingly, cardiac MRI suggested intracardiac thrombus within the right atrial appendage and patent foramen ovale (Figure 1B), and possible amyloidosis from delayed gadolinium uptake. Despite negative serologic amyloid workup, pyrophosphate scan confirmed transthyretin amyloidosis. The patient was diuresed for decompensated heart failure but hypotension and acute-on-chronic kidney disease limited Guidelines-Directed Medical Therapy at discharge. Discussion: This case elucidates the importance of recognizing the thromboembolic risk in cardiac amyloidosis patients. Studies indicate up to 30% of cardiac amyloidosis patients have intracardiac thrombi, particularly those with primary amyloidosis subtype. Notably, no correlation exists between the CHA2DS2-VASc score and the presence of left atrial appendage thrombus in patients with cardiac amyloidosis and atrial fibrillation. Despite the left atrial appendage being twice more susceptible to thrombus formation, the right atrial appendage requires attention. Timely screening in high-risk patients could enable early thrombus detection, potentially improving prognosis.