PFO Closure for Obstructive Sleep Apnoea

Obstructive sleep apnoea (OSA) is a condition which involves episodes of interrupted breathing during sleep due to repetitive narrowing or collapse of the throat. These episodes are usually associated with a drop in blood oxygen levels and brief awakenings, which disrupt the sleep of those affected and can lead to daytime sleepiness. OSA is associated with an increased risk of heart disease and stroke. In some individuals, the low oxygen levels in the blood can be made worse by also having a small hole in the heart, called a patent foramen ovale (PFO). This hole is present at birth in everyone, but in some people (about 30% of the normal population) it fails to close. Usually a PFO does not cause any medical problems. However, it may be recommended to have a PFO closed by key-hole surgery if someone suffers a stroke, severe migraine or if they are professional divers. There is a higher incidence of PFO in patients with OSA (25-50%) compared to the wider population and this may account for some of the observed increased risk of heart disease and stroke in patients with OSA. This study will assess the number of patients with OSA who also have a PFO, and whether closing the PFO can improve the symptoms of OSA (e.g. sleepiness, exercise capacity and general well-being), thereby enabling the patient to not be reliant on treatment for OSA. If the study shows that closing the PFO is beneficial then the investigators will assess in a larger study if this treatment can also reduce heart disease and strokes.