Background: Necropsy studies have shown that nonbacterial thrombotic endocarditis (NBTE) may be associated with cerebral infarctions and antemortem diagnosis is now possible. However, the best treatment for patients with NBTE presenting with stroke is not known. We describe three patients presenting with an acute embolic stroke secondary to large,mobile vegetations detected by transthoracic (one case) or transesophageal echocardiography (two cases). All patients underwent surgery for removal of the vegetations to prevent recurrent embolic events; valve replacement was necessary in two cases. The sterile nature of the vegetations was confirmed by pathological examination and negative stains and cultures of the surgical samples. A previously unrecognized hypercoagulable condition was diagnosed in all patients (antiphospholipid antibody syndrome in two cases and disseminated adenocarcinoma in one case).
Conclusion: NBTE should be considered among the possible causes of embolic stroke even in the absence of history of cancer, hypercoagulability, or previous embolic manifestations. If NBTE is diagnosed, the possibility of underlying thrombophilia should be thoroughly investigated. Valvular surgery represents a valuable therapeutic alternative in patients with large mobile vegetations, valvular dysfunction or recurrent embolic events despite anticoagulation.