The full spectrum of PFO: Are we seeing just the tip of the iceberg?

A patent foramen ovale (PFO) is the most common congenital heart defect and is present in about 25% of adults. Emerging data recognize that the presence of a PFO is causally associated with a wide range of pathologies including stroke, myocardial infarction, peripheral ischemia, migraine with aura, and hypoxemia. Although recent randomized trials have established the superiority of PFO closure over medical therapy for secondary prevention of stroke without competitive causes, the practice of blaming a PFO for a stroke only in the absence of other stroke causes has resulted in considerable underestimation of the real-life prevalence of paradoxical embolism. Moreover, we are now beginning to understand that not all PFOs are created equal and some may exhibit “high-risk” features. With improvement in the procedural technique and safety profile of device closure, percutaneous PFO closure is considered among the safest interventional cardiology procedures, with robust long-term clinical yield. This chapter provides a unique perspective on percutaneous PFO closure, highlighting both what is known, and how these data can be extrapolated to other PFO-associated conditions.