Patent foramen ovale and atrial septal defects: A focused overview

The foramen ovale is a key fetal cardiac structure enabling oxygenated blood flow from the right to the left atrium, bypassing the non-functional fetal lungs. Postnatally, this opening typically closes due to increased left-sided atrial pressure. However, the closure remains incomplete in approximately 25%-30% of adults, resulting in a Patent Foramen Ovale (PFO), which can have significant clinical implications. PFO has been associated with cryptogenic strokes, migraines, Platypnea-Orthodeoxia Syndrome (POS) and decompression sickness. In cryptogenic strokes, PFO serves as a potential pathway for paradoxical embolism. Migraine, particularly with aura, has shown a correlation with PFO, although trials like MIST and PREMIUM did not support routine PFO closure for migraines. Diagnosis of PFO includes Transthoracic (TTE) and Transesophageal Echocardiography (TEE), with TEE being the gold standard due to its high sensitivity and specificity. Management strategies for PFO-associated strokes involve medical therapy (antiplatelets or anticoagulants) and transcatheter closure. Trials such as CLOSURE, RESPECT and DEFENSE-PFO demonstrated variable outcomes, with newer guidelines advocating cl