LAUSR

Introduction Apixaban, a direct factor Xa inhibitor, is one of the oral anticoagulant drugs (available since 2012) for stroke prevention in patients with nonvalvular atrial fibrillation. Other indications for its use include deep venous thrombosis, postoperative venous thromboprophylaxis, and pulmonary embolism. The ARISTOTLE trial showed that apixaban was superior to warfarin in preventing stroke or systemic embolic event and was associated with less bleeding and lower mortality rates. Major bleeding was the primary safety endpoint in the trial and was defined as “clinically overt bleeding accompanied by 1 or more of the following: bleeding that was fatal, bleeding that occurred in at least 1 of the following critical sites: intracranial, intraspinal, intraocular, pericardial, intra-articular, intramuscular with compartment syndrome, and retroperitoneal; a transfusion of 2 or more units of packed red blood cells; or a decrease in hemoglobin of 2 g/dL or more.” Neither the supplementary appendices in the ARISTOTLE trial nor any of the study tables break down each of the sites of major bleeding, and they lump the safety outcome as any major bleeding. Bleeding in the pericardial space, hemopericardium, can be a life-threatening adverse reaction and should be monitored for. An extensive literature search showed 1 prior case report of spontaneous hemopericardium in a patient receiving apixaban, none reported in the United States. We present the first reported case series of hemopericardium in association with apixaban therapy in the United States.