Non-infective endocarditis

### Learning objectives Endocarditis is defined as inflammation of the endocardium, the lining of the cardiac chambers and valves, and characterised by vegetations, most commonly caused by infection with bacteria or fungi. Non-infective endocarditis, also known as non-bacterial thrombotic endocarditis (NBTE) or aseptic endocarditis, refers to a rare condition characterised by formation of sterile vegetations. Without treatment, these can lead to valve dysfunction, heart failure, systemic embolism and death. Herein, we review the pathophysiology, clinical features, diagnosis and treatment of NBTE. The first description of sterile vegetations on the heart valves was provided by Zeigler in 1888.1 Libman and Sacks then published a case series of four patients in 1924 which associated these atypical lesions with systemic lupus erythematosus (SLE).2 These vegetations are not associated with an inflammatory response or bacteraemia and commonly occur as a result of fibrin deposition and platelet aggregation. Sterile vegetations can develop in a number of conditions, including autoimmune disease, malignancy and hypercoagulable states. Although Libman–Sacks endocarditis refers specifically to NBTE seen in patients with the autoimmune disorders SLE and antiphospholipid syndrome (APLS), other interchangeable terminology for NBTE includes verrucous endocarditis and marantic endocarditis. A vegetation is defined as an oscillating intra-cardiac mass on a valve (or its supporting structure) or implanted material. The rapid evolution of echocardiographic imaging techniques has resulted in higher rates of vegetation detection in more recent studies using these developed imaging modalities.3 4 NBTE is a rare condition and most commonly diagnosed at post-mortem. The exact incidence is unknown but rates of up to 3.7% have …