Role of closure of patent foramen ovale in cryptogenic stroke: Current status.

Ischaemic stroke is among the leading causes of disability and death. Despite extensive vascular, cardiac and serological evaluations, the cause remains unknown in 20%-40% of patients. These are classified as cryptogenic stroke. Paradoxical embolism is one of the many causes of cryptogenic stroke. The term paradoxical embolism is used to describe an embolus of venous origin entering the systemic circulation through a patent foramen ovale (PFO), atrial septal defect (ASD), ventricular septal defect or extracardiac communication such as pulmonary arteriovenous malformation. PFO is present in about 25% of the population. PFO is seen more commonly in patients with cryptogenic stroke. Secondary prevention of stroke in such patients includes the prevention of formation of a thrombus with antiplatelets, vitamin K antagonists or closure of the PFO by either surgery or the percutaneous route. Percutaneous closure using devices has been shown to be safe and beneficial in preventing secondary stroke. Data from randomized trials have shown device closure to be superior to medical management in the secondary prevention of cryptogenic stroke due to PFO.