Large Left Atrial Thrombus on Amplatzer Septal Occluder Secondary to Medication Nonadherence.

Patent foramen ovale (PFO) is a common clinical entity that is encountered in 20-34% of the general population. In most individuals, this anatomical variation is asymptomatic and goes undetected throughout their lives or is only incidentally discovered on cardiac investigations. In situations when the conduit is large enough and when the right atrial pressure exceeds the left atrial pressure, right to left interatrial flow may occur in these individuals. This creates a channel for translocation of air or thrombi from the venous to the arterial circulation, a phenomenon known as paradoxical embolism. Approximately 25-40% of strokes and transient ischemic attacks in patients less than 60 years of age are classified as cryptogenic and studies have identified a higher prevalence (60%) of PFO in young adults with strokes of unidentifiable etiology. Recent trials have demonstrated utility of PFO closure with mechanical devices for secondary prevention of recurrent strokes in patients aged <60 years of age. The general consensus of post-operative management of PFO closure has been largely drawn from randomized controlled trials and comprises use of aspirin and clopidogrel for 6 months followed by use of aspirin alone for at least 5 years. We present a case of an incidentally discovered left intra-atrial thrombus attached to a PFO closure device in a 36-year-old female with a history of cryptogenic stroke three months after implantation.