Challenges of Echocardiographic Diagnosis of Pericardial Hematoma vs Right Atrial Thrombus

Abstract

Pericardial hematoma causing right atrial (RA) compression following cardiac surgery is a known postoperative complication, and has been reported in the literature since as early as 1985. A postoperative pericardial hematoma has echocardiographic characteristics that can make its differentiation from an RA thrombus challenging. The ability to differentiate between pericardial hematoma and RA thrombus via bedside point-of-care ultrasound or formal transthoracic ultrasound is crucial as a prompt diagnosis may lead to expedited treatment and improved patient outcomes. CASE PRESENTATION:A 40-year-old woman with antiphospholipid syndrome on warfarin, systemic lupus erythematous, and severe mitral valve and tricuspid valve regurgitation due to marantic endocarditis, underwent bioprosthetic mitral valve replacement and tricuspid valve repair. Three days after discharge, she presented to the emergency department (ED) with chest pain. She was hypoxic with an oxygen saturation of 60%. She was intubated and became pulseless requiring cardiopulmonary resuscitation, with rapid return of spontaneous circulation. An ED physician's bedside ultrasound showed a newly reduced ejection fraction of 10%. A transthoracic echocardiogram (TTE) was concerning for an RA thrombus with near obliteration of the right atrial cavity. Transesophageal echocardiogram (TEE) was concerning for RA thrombus vs pericardial hematoma. She was emergently brought to the operating room and was found to have compression of the right atrium by a pericardial hematoma. The hematoma was evacuated and she was discharged to home on hospital day 22. Figure 1 highlights TTE and TEE findings. DISCUSSION:The differentiation between pericardial hematoma and right atrial thrombus via echocardiogram can be difficult due to the variable appearance of pericardial hematomas in regards to their echodensity. Pericardial hematomas can appear anywhere from hypoechoic to hyperechoic on echocardiogram, depending on how much clotting has occurred within this collection of blood. A hypoechoic hematoma that is compressing the RA can be mistaken for the RA chamber itself, while a hyperechoic hematoma may resemble a thrombus. The following features are suggestive of the diagnosis of pericardial hematoma: restriction to a superior-lateral location, rounded borders extending into the RA, and an area of central echolucency within the culprit area. This case highlights the challenges of diagnosis of postoperative pericardial hematoma by echocardiography, and the characteristics that can be used to differentiate between pericardial hematoma and right atrial thrombus.CONCLUSIONS: Diagnosis of post-operative pericardial hematoma by echocardiography can be challenging. Being aware of the characteristics that differentiate pericardial hematoma from thrombus may help guide diagnosis and expedite treatment.