Non-bacterial Thrombotic Endocarditis (NBTE) in the Absence of Malignancy or Lupus Anticoagulant/Antiphospholipid Antibodies: A Case Report.

Non-bacterial thrombotic endocarditis (NBTE) is a very rare condition characterized by sterile thrombi formation on cardiac valves and is often associated with hypercoagulation states, such as malignancy and autoimmune disorders. We present the case of a 74-year-old patient admitted to the intensive care unit with acute respiratory failure, who had a history of COVID-19 infection five months prior to admission, despite having received certified vaccination. The patient developed NBTE involving the mitral valve, alongside acute respiratory distress syndrome (ARDS). In spite of the exclusion of cancer and systemic connective tissue disorders, the patient's condition rapidly deteriorated, leading to treatment-resistant multi-organ failure and demise, despite aggressive management, including anticoagulation therapy, mechanical ventilation, and renal replacement therapy. This case underscores the need for further research into the mechanisms underlying NBTE in the absence of traditional risk factors. Additionally, it highlights the importance of long-term anticoagulant therapy in NBTE management to mitigate the risk of embolic complications. Our case contributes to the growing body of literature identifying a subset of NBTE cancer-free patients with distinct characteristics, including those associated with current or past COVID-19 infection.