Culture-Negative Infective Endocarditis Post-mitral Valve Repair: A Case Illustrating the Role of Advanced Imaging in Surgical Decision-Making

Endocarditis is a rare but serious condition that can occur in patients with valvular heart disease, particularly after valvular repair or in those with prosthetic heart valves. While it is generally considered less common following successful valvular repairs without evidence of active infection, endocarditis can present in a variety of ways, including as an incidental finding in patients with stroke. Stroke in the setting of endocarditis is often caused by embolic events originating from infected valve leaflets or vegetations. Although blood cultures remain the gold standard for diagnosing infective endocarditis, negative blood cultures are not uncommon, particularly in early or indolent cases. Advanced imaging modalities, such as transesophageal echocardiography (TEE) and cardiac computed tomography (CT), play a crucial role in identifying valve abnormalities, vegetations, and other structural heart lesions that may suggest endocarditis, especially when blood cultures fail to provide a definitive diagnosis. This case report focuses on the diagnostic challenges and the role of advanced imaging in a patient with a history of prior mitral valve repair who presented with recurrent stroke events but was otherwise asymptomatic. Despite initial negative blood cultures, suggestive of early or indolent endocarditis, serial imaging with cardiac CT and TEE guided clinical decision-making and timely intervention. Dynamic changes in echogenic structures over time prompted surgical intervention before microbiologic confirmation, underscoring the importance of imaging in prosthetic valve patients who may present atypically, such as with stroke as the sole manifestation. In addition, the study explores whether stroke can be the sole presenting symptom of endocarditis in patients with valvular disease or repair. The case further emphasizes the need for high suspicion of endocarditis in patients with valvular heart disease, especially those with embolic events, and underscores the importance of timely imaging to guide management decisions. This case also provides a review of similar reports in the literature, reinforcing the role of cardiac CT and TEE in diagnosing endocarditis in patients with valvular disease and prosthetic valve repairs.