PFO and Stroke: What Is the Connection?
A patent foramen ovale — usually shortened to PFO — is common and normally causes no problems. But when somebody has had a stroke without another clear explanation, doctors may investigate whether a PFO could have played a part.
What is a PFO?
A PFO is a small flap-like opening between the two upper chambers of the heart that remains after birth.
Before birth, this opening is a normal and important part of a baby's circulation. It usually closes after birth, but in roughly one in four adults it remains partly open.
For most people this never causes symptoms and they may go through life without ever knowing they have one.
How could a PFO be connected with stroke?
Normally, a blood clot travelling through the veins reaches the right side of the heart and then travels towards the lungs.
If somebody has a PFO, under certain circumstances a clot may be able to cross from the right side of the heart to the left.
From there it can enter the arterial circulation. If it travels to an artery supplying the brain and blocks blood flow, it can cause an ischaemic stroke.
Many people who have never had a stroke also have a PFO, so doctors consider the PFO alongside the person's age, stroke pattern, medical history and other investigations.
My stroke eventually led to the discovery of my PFO
I had my stroke at 44. I was active, exercising regularly and did not consider myself someone who was likely to have a stroke.
After the immediate hospital investigations, the search for the reason it had happened continued.
Over time I had a number of heart investigations, including echocardiograms, a bubble study and a transoesophageal echocardiogram. A PFO was identified.
Eventually I was referred to Leeds General Infirmary and underwent a PFO closure procedure.
My experience isn't everybody's pathway
A PFO was part of my own investigation and treatment journey. That does not mean somebody else's stroke has the same cause or that everyone with a PFO needs treatment.
Neil — stroke survivor and founder of Stroke Health Fitness.
How might doctors find a PFO?
A PFO is not necessarily obvious on a routine examination. Different tests may be used depending on the individual situation.
Echocardiogram
Ultrasound can be used to examine the structure and function of the heart.
Bubble study
Saline containing tiny bubbles is injected into a vein while the heart is imaged. The movement of bubbles can help identify a right-to-left passage through the heart.
Transoesophageal echo
An ultrasound probe passed into the oesophagus can provide detailed images of the heart and the area around a PFO.
Why is PFO sometimes discussed after a younger stroke?
When a younger adult has an ischaemic stroke and common causes such as significant arterial disease or another clear cardiac source are not identified, doctors may investigate less obvious possibilities.
That can include looking for a PFO.
The difficult question is not simply:
It is: “How likely is it that this particular PFO was relevant to this particular stroke?”
Does every PFO need closing?
No. Most PFOs need no treatment at all.
PFO closure may be considered for selected people who have experienced a stroke where specialists believe paradoxical embolism through the PFO is a likely explanation.
Decisions about closure involve specialist assessment and consideration of the potential benefits, alternative treatment and procedural risks.
That decision belongs with the stroke and cardiology teams who know the individual's medical history and investigations.
What happens during PFO closure?
PFO closure is usually performed using a catheter-based or “keyhole” technique rather than open-heart surgery.
A catheter is introduced through a vein, commonly at the groin, and guided into the heart. A closure device is positioned across the PFO and remains in place while the body's tissue gradually heals around it.
The procedure
Imaging is used to guide the device into the correct position. Depending on the centre and individual circumstances, sedation or anaesthesia may be used.
Afterwards
Follow-up and medication are determined by the treating team. Patients should follow their own hospital's instructions about activity, driving, medication and return to work.
My PFO closure experience
I had my closure at Leeds General Infirmary during the COVID period, which meant my wife dropped me at the hospital entrance and I went through the admission and procedure without visitors.
The procedure itself involved accessing the heart through the groin. Afterwards I had some bleeding from the access site, which meant I stayed in hospital overnight rather than going straight home.
I was checked again the following day and then discharged.
One of the things my experience taught me was that even something described as a relatively straightforward procedure can feel very significant when you're the person lying in the hospital bed.
PFO closure wasn't the end of my story
I initially hoped closing the PFO might provide a neat ending to the question of my stroke.
Life turned out to be more complicated. Later, atrial fibrillation and flutter also became part of my medical story.
That's another reason I think it is important not to reduce somebody's health history to a single finding.
Questions people ask about PFO and stroke
Can a PFO cause a stroke?
A PFO can potentially allow a blood clot to cross from the venous circulation into the arterial circulation, where it could reach the brain. But simply finding a PFO does not prove that it caused an individual's stroke.
How common is a PFO?
PFOs are common, with estimates suggesting roughly 20–25% of adults have one. Most never know about it and experience no problem from it.
Does everyone with a PFO need treatment?
No. Most PFOs do not require treatment. Closure is considered in selected circumstances after specialist assessment.
Why might a PFO be found after a stroke?
When no clear cause of an ischaemic stroke has been identified, particularly in a younger person, investigations may include looking for a possible route through which a clot could have reached the brain.
Does PFO closure guarantee another stroke won't happen?
No. PFO closure can reduce recurrent stroke risk in appropriately selected patients, but it cannot guarantee that another stroke will never occur.
Continue exploring
Stroke in Younger Adults
Explore why stroke can happen earlier in life and what recovery may involve.
Explore younger stroke →My Stroke Journey
Follow my experience from stroke through investigation, PFO closure and life afterwards.
Read my journey →Understanding Stroke
Explore stroke symptoms, causes and other important topics.
Understanding Stroke →Trusted information
SHF combines lived experience with established UK healthcare information.
Medical information
This page provides general information and lived experience. It cannot diagnose a PFO, determine whether a PFO caused somebody's stroke or advise whether PFO closure is appropriate.
Decisions about investigation, medication and treatment should be made with appropriately qualified healthcare professionals.
Read the full Stroke Health Fitness Medical & Fitness Disclaimer .
Finding an answer can sometimes be a journey in itself.
Understanding what happened is one part of stroke recovery. The next challenge is deciding how to move forward with everything that comes afterwards.
Life after stroke. Moving forward.