Abstract 4367374: Paradoxical Embolism from a Port-a-Catheter-Associated Thrombus Striking a Patent Foramen Ovale: A Rare Cause of TIA

Background: Paradoxical embolism through a patent foramen ovale (PFO) is a recognized cause of cryptogenic stroke and transient ischemic attacks (TIAs), especially in patients with intracardiac right-to-left shunting. Indwelling central venous catheters may lead to thrombus formation, but direct embolic events from catheter-associated thrombi interacting with a PFO are exceedingly rare and underrecognized. Case: A 39-year-old woman with a history of thalassemia, anemia, agoraphobia, anxiety, gastric bypass surgery, liver dysfunction, and multiple prior C-sections, a port-a-cath for recurrent blood transfusions presented with acute altered mental status, confusion, agitation, and restlessness. CT head showed subtle findings concerning for infarction in the right temporal and parietal lobes, although MRI brain was unremarkable. Her neurologic status returned to baseline. A transthoracic echocardiogram (TTE) with bubble study revealed right-to-left atrial shunting, raising suspicion for PFO. She was discharged with cardiology and neurology follow-up. At follow-up, she remained emotionally distressed and convinced she had suffered a stroke. Repeat TTE raised concern for an intracardiac mass. A transesophageal echocardiogram (TEE) revealed a port-a-catheter tip in the right atrium with a large, mobile thrombus attached to its distal end. A small PFO with intermittent right-to-left shunting was also identified. The thrombus moved like a pendulum, intermittently striking the interatrial septum at the PFO. It is likely that embolization of a portion of the thrombus through the PFO led to a TIA. Interventional Radiology administered catheter-directed tPA to facilitate clot dissolution. Discussion: This case highlights a rare but clinically significant mechanism of paradoxical embolism originating from a central venous catheter, diagnosed through high clinical suspicion and confirmatory imaging. Conclusion: In patients with neurologic symptoms and indwelling catheters, paradoxical embolism should be considered. TEE plays a vital role in detecting thrombi and intracardiac shunts. Early recognition and targeted therapy may prevent recurrence of embolic events.