Patent foramen ovale and divers

Abstract

A patent foramen ovale (PFO) occurs in approximately 27-30 % of the population (Thompson and Evans, Q J Med 23:135-52, 1930; Hagen et al. Mayo Clin Proc 59:17-20, 1984) and has been linked to paradoxical embolism, cryptogenic stroke, migraine and an increased risk of decompression illness (DCI) in divers.Recent estimates have suggested that over 15 million people worldwide are participating in recreational diving, with greater than 250,000 dives per year (UN atlas of the Oceans. 2006.http://www.oceanaltas.org). Decompression sickness is estimated to occur in one per every 6,369 dives deeper than 30 m of sea water (St Leger Dowse et al., Aviat Space Environ Med 73:743-9, 2002). However, those with PFOs have been shown to have a fivefold increase in the risk of experiencing decompression illness (Torti et al., Eur Heart J 25:1014-20, 2004). This, and recent studies describing a higher incidence of subclinical cerebral damage in divers with PFOs has led to increasing numbers of divers seeking out screening for the presence of a PFO and elective PFO closure. In the absence of definitive practice guidelines, the clinical management of such patients remains challenging. In this chapter we review the pathophysiology of diving and PFOs, the potential risks associated with the presence of a PFO in divers, as well as some proposed methods of screening and managing this patient group.