Patent foramen ovale: where are we in 2009?

Patent Foramen Ovale (PFO) is present in 20 - 25% of the population, and is known to be associated with a number of clinical syndromes. However, it is less clear that there is a causal (or contributory) role for the PFO in the development of thromboembolic stroke, systemic thromboembolization, decompression illness in divers, hypoxemia with obstructive sleep apnea, or migraine headaches. On-going and new randomized prospective trials are testing these relationships and are attempting to prove therapeutic benefit to closing the defects. This paper will review the existing literature on PFO, and will attempt to clarify some of the outstanding clinical management issues.