Patent Foramen Ovale Closure
PFO closure is relevant in 4 clinical situations
1 For those who have a stroke because a clot from the leg passes across the PFO and is embolised to important organs such as the brain, causing stroke or transient global amnesia, or the heart, causing heart attack. This phenomenon, of a clot crossing from the right to the left side of the circulation, is known as paradoxical embolus or embolism.
2 For divers who suffer decompression illness which is caused by bubbles from the venous circulation (which are generated in the veins of divers undertaking fairly standard dives) crossing over the PFO and being sent into tissues already loaded up with dissolved nitrogen.
3 For those who suffer migraine with aura, where there is a proven link with PFO, but there remains uncertainty how much benefit may be associated with closing the PFO in this clinical situation.
4 For those who suffer low oxygen levels in particularly when this is positional, because deoxygenated blood flows across the PFO into the left side of the circulation. This usually occurs in older patients with enlargement of the aorta, or if it occurs in younger patients, it is usually due to hsvign a very abnormal atrial septum.
PFO for prevention of paradoxical embolism / stroke prevention
This is the most common reason for PFO closure in the UK and Worldwide. 700-900 procedures are performed each year in the UK, but only about 10 hospitals perform more than 30 procedures. National guidelines suggest that cardiologists should perform more than 40 congenital heart procedures a year, and lead interventionalists 80. It is widely accepted that if you perform a good volume of a procedure it allows you to become safer and more efficient, so you should always ask how many of a certain type of procedure the operator has performed. There are recent studies that give a strong signal that PFO closure reduces recurrent strokes when the first stroke was likely to have been caused by paradoxical embolism (a clot from the leg crossing the PFO).
PFO for divers
Dr Turner has a particular interest in the problem of PFO in divers. Not only does he have a large experience of PFO closure, but he was also trained in diving and diving medicine in the Royal Navy, including treating divers in recompression chambers. He is also recognised as a Medical Referree for the UK Sports Diving Medical Committee, as well as being Vive-Chairman of the Committee and conference organiser 2011 and 2013. The details surrounding the diving illness, such as the dive profiles, breathing gas and activity in the water and on the surface are all relevant in making decisions about whether PFO closure is likely to be appropriate. Thus it is important for divers to see cardiologists with experience in assessing divers who have PFO-related decompression illness. NICE Guidelines also indicate that this is appropriate, so divers should ensure that the cardiologist they see has appropriate training and experience to advise them. The 2 cardiologists currently recognised by the UK Sports Diving Medical Committee as referees, who also regularly assess divers for this problem, are Dr Wilmshurst and Dr Turner.
PFO closure for migraine
Cardiologists who regularly close PFOs for stroke, observe that many of these patients also have migraine with aura. Furthermore, many of these patients report a reduction in migraine symptoms after closure. This observation has not been properly tested in a well designed randomised trial, as the only trial that set out to test the hypothesis that PFO closure would reduce migraine has been widely criticised and has been the subject of legal proceedings against the original cardiology principle investigator, and also the subject of some GMC proceedings. The results were not conclusive and did not reach the primary end point, so does not provide evidence for closing PFOs solely to reduce migraine. It is however an ongoing hypothesis, but NICE indicated that it should not be routine practice.
PFO Closure for deoxygenation (Orthodeoxia Platypnea)
This is very rare, so you need to be assessed by a specialist cardiologist. Small PFOs do not usually cause this, and the right to left shunt needs to be at rest in order to make the diagnosis possible. The commonest type of patient that suffers this also has enlargement of the aorta, which can distort the atrial septum. These procedures are technically more challenging and should be performed by experienced operators. However, many patients feel massively better after the PFO closure, as it can improve their oxygen levels to normal, or at least near normal.