Case report: Thrombus in transit—a cause of impending paradoxical embolism

A thrombus in transit (TIT) is a life-threatening condition associated with pulmonary embolism (PE). While TIT was once considered a rare diagnosis, its emergence has risen in recent years mainly through advancement in medical technology. Rare cases of a thrombus in transit crossing a patent foramen ovale in the context of pulmonary embolism have been reported. The appropriate treatment of patients in this setting remains unclear.

We describe a 64-year-old man who presented with syncope to the emergency room secondary to acute pulmonary embolism. Initial transthoracic echocardiogram revealed a large intracardiac thrombus in transit across a patent foramen ovale, verified by transoesophageal echocardiogram. He underwent anticoagulation and urgent surgical thrombectomy with a favourable outcome.

Risk stratification of patient with acute PE is mandatory for determining the appropriate therapeutic management. Initial risk stratification is based on clinical symptoms and signs of haemodynamic instability which indicate a high risk or early death associated massive PE. Thrombolytic therapy is indicated in high-risk patients (Grade 1B), while anticoagulation alone is recommended for intermediate-high- to low-risk patients. Assessment for intracardiac thrombi in PE modifies the treatment strategy in case of a thrombus in transit.