Paradoxical Cerebral Embolization Caused by Thrombus-In-Transit via a Patent Foramen Ovale in a Patient with Symptomatic Pulmonary Embolism: A Case Report

OBJECTIVE: Acute pulmonary embolism (PE) is a life-threatening cardiovascular event associated with high mortality and morbidity. The presence of a patent foramen ovale (PFO) in patients with acute PE represents a risk factor for mortality. Furthermore, a thrombus-in-transit via a PFO with impending paradoxical embolism carries a high mortality rate. CASE PRESENTATION: An adult patient with ischemic stroke caused by paradoxical embolism following PE underwent mechanical thrombectomy and achieved successful recanalization. Initial CT pulmonary angiography (CTPA) showed not only pulmonary thromboemboli but also bilateral atrial thromboemboli. During hospitalization, transesophageal echocardiography (TEE) revealed the PFO with a right-to-left shunt. Two months after rehabilitation undergone by the patient, PE completely disappeared and PFO closure was conducted to reduce the recurrence risk of ischemic stroke. CONCLUSION: Not only cardiologists but also interventional neurologists should understand that CTPA can demonstrate the thrombus-in-transit through the PFO and provides a reliable prediction of the sudden onset of ischemic stroke in patients with symptomatic PE. When identified, considering a case-by-case treatment approach by multidisciplinary teams is essential for preventing further life-threatening paradoxical embolization.