Computed tomography perfusion-guided mechanical thrombectomy and histopathological analysis of a fibrin-rich septic embolus in infective endocarditis-related internal carotid artery occlusion

Background: Infective endocarditis (IE) could cause cerebral infarction through septic embolization, presenting challenges in both diagnosis and treatment. Because intravenous thrombolysis is contraindicated in suspected IE-related stroke, careful evaluation of cerebral perfusion and infarct extent is crucial for selecting appropriate therapy. Case Description: A 45-year-old woman was admitted to the emergency department with fever and disturbance of consciousness. Imaging revealed a cerebral infarction due to right internal carotid artery (ICA) occlusion. Echocardiography demonstrated a vegetation on the mitral valve, suggesting IE as the embolic source. As the onset time was unclear and no diffusion-weighted image-fluid-attenuated inversion recovery mismatch was observed, intravenous alteplase was considered inappropriate. Although the neurological deficit was mild, computed tomography perfusion (CTP) imaging showed extensive hypoperfusion in the right ICA-middle cerebral artery territory with a limited infarct core. Mechanical thrombectomy was therefore performed. The procedure was technically challenging, requiring a switch from aspiration thrombectomy to a combined stent retriever technique, ultimately achieving successful recanalization (thrombolysis in cerebral infarction grade 2b). Histopathological examination of the retrieved thrombus revealed fibrin-rich material containing bacterial colonies, and blood cultures were positive for Staphylococcus aureus . Subsequently, the mitral vegetation enlarged, necessitating urgent mitral valve replacement. Conclusion: This case illustrates the usefulness of CTP imaging in guiding treatment decisions for low National Institutes of Health Stroke Scale large-vessel occlusion associated with IE. It also emphasizes that histopathological examination of retrieved thrombi could provide valuable insights into the underlying infectious etiology and inform subsequent management strategies.