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.