Patent Foramen Ovale (PFO)

Patent foramen ovale (PFO) is when you have a small flap or opening between the upper chambers (atria) of your heart. Everyone has this opening before birth. It’s called a foramen ovale. It usually closes before age 3. “Patent” means “open,” and “patent foramen ovale” means the foramen ovale is still open after your third birthday.

PFO is somewhat common. Experts estimate that up to 1 in 4 adults have it. But most of the time, PFO doesn’t cause symptoms and won’t need treatment. But some uncommon problems related to having a PFO include stroke and transient ischemic attacks.

What does a foramen ovale do?

A fetus doesn’t use its lungs to get oxygen-rich blood. Instead, it comes from the placenta, delivered through the umbilical cord. Oxygen-rich blood from the umbilical cord enters the fetus’s heart and then uses the foramen ovale as a shortcut.

Taking that shortcut means blood skips the lungs (which aren’t doing anything yet). It goes straight from the heart’s right upper chamber (right atrium) to the left upper chamber (left atrium). From there, the blood eventually pumps out to the fetus’s brain (and everywhere else in its body).

The foramen ovale should naturally close when your baby starts breathing and blood goes to their lungs to get oxygen. The shortcut isn’t needed anymore, so it closes up.

Who might have patent foramen ovale?

Anyone can have patent foramen ovale. But people who need an echocardiogram for certain reasons are more likely to get a diagnosis. That usually affects:

• Divers with decompression sickness (barotrauma): Under high pressure, gases in your blood compress. Fast pressure drops, like in underwater divers who come up too quickly, can make those gases expand and form bubbles. Those bubbles block blood flow.
• People with cryptogenic strokes: About 3 in 10 strokes are cryptogenic, meaning they have an unknown cause. Medical testing after an unexplained stroke often finds a PFO, especially in people under 60. As many as 1 in 2 people under 60 with cryptogenic strokes have a PFO.
• Mountain climbers: A PFO might make you more likely to develop altitude sickness conditions like high-altitude pulmonary edema (HAPE).

How does patent foramen ovale affect my body?

A PFO is a small opening that lets blood leak between your heart’s upper chambers. It’s usually not a problem unless the leak is big enough. When it is, blood clots can slip through the opening. Those clots can either be from:

• Somewhere else in your body: An example of this would be a clot from deep vein thrombosis (DVT) in your legs.
• Within your heart itself: Blood that doesn’t flow properly can pool and start to clot inside your heart. Those clots can easily pass through a PFO and head anywhere in your body.

Clots that make it through a PFO can easily head straight to vital places like your brain. Once there, a clot can get stuck in tiny blood vessels and block blood flow, causing an ischemic stroke. Clots can also get stuck in other critical places, like inside the tiny blood vessels in your kidneys.

Symptoms of patent foramen ovale

PFO usually doesn’t cause symptoms unless the opening is big enough for a lot of blood to pass through. That’s rare, but it can cause:

• Low blood oxygen levels or symptoms of it
• Migraines or migraine-like headaches
• Shortness of breath while sitting or standing (platypnea-orthodeoxia syndrome)
• Ischemia symptoms in your limbs or organs, like your kidneys

It’s much more common for healthcare providers to find a PFO when trying to find a reason why you had a:

• Stroke
• Transient ischemic attacks (often incorrectly called “mini-strokes")
• Heart attack

Patent foramen ovale causes

Experts aren’t sure why PFO happens. But research shows it could be at least partly genetic.

How doctors diagnose patent foramen ovale

Healthcare providers can diagnose PFO with a combination of methods. One easy way they might detect it is by just listening to your heart with a stethoscope (though this isn’t common). Your provider might be able to hear a murmur from the flow of blood through the PFO.

Echocardiograms are the main test to diagnose a PFO. There are two specific types of echocardiogram your provider might recommend:

• Transthoracic echocardiogram (TTE): This type of echocardiogram looks at your heart from outside your body. It uses a wand held to the skin of your chest. Sound waves from the wand help create a picture of the inside of your heart.
• Transesophageal echocardiogram (TEE): This is like TTE, but it looks at your heart from inside your body. Your esophagus passes right next to your heart. That means an echocardiogram probe inserted into your esophagus can get detailed pictures of your heart’s insides.

Your provider may also suggest a bubble test with an echocardiogram or transcranial Doppler (TCD) ultrasound. During a bubble test, they inject saltwater solution into your vein. The TCD ultrasound can detect the bubbles in your head if they pass through the PFO. An echocardiogram can show the bubbles as they pass through a PFO in your heart.

How is patent foramen ovale treated?

Most people with PFO won’t need treatment. But your provider may recommend treatment if you have a history or high risk of stroke or blood clots. Treatments can include:

• Medications: Blood-thinning medications (anticoagulants) can prevent blood clots. Examples include aspirin, clopidogrel (Plavix®) or warfarin (Coumadin™, Jantoven®). You might need to take these while you recover from a procedure to close a PFO, too.
• Endovascular surgery: This is when a provider uses a small tube-shaped device called a catheter. They’ll insert it into a major vein and then thread the tube up to your heart. That lets them place a closure device into the PFO, sealing it up from inside your heart.
• Heart surgery: If endovascular surgery isn’t an option, your provider may recommend another type of surgery. That includes minimally invasive heart surgery, robot-assisted surgery or open-heart surgery.

The best treatment for you depends on several factors. Your healthcare provider is the best person to explain your options.

Complications of treatment

The treatments for PFO can sometimes cause complications, but this isn’t common. The complications vary by treatment. Some of the possible complications include:

• Bleeding: This can happen with any treatment, but especially with medications. That bleeding can be dangerous depending on where it happens, like with brain bleeds.
• Blood clots: These can happen for many reasons, including atrial fibrillation. Medications can prevent clots so they don’t lead to dangerous issues, like pulmonary embolism or stroke.
• Inflammation inside your heart (endocarditis): This can sometimes happen with infections after catheter-based and surgical procedures.
• Irregular heart rhythms: Closing a PFO with a device can sometimes cause atrial fibrillation. This isn’t common. When it does happen, atrial fibrillation usually occurs in short-lived episodes.
• Nearby tissue damage: Damage to the surrounding heart or blood vessel tissue can sometimes happen with procedures to close a PFO. This isn’t common, but it can lead to issues like cardiac tamponade or embolism.
• Unsuccessful closure: Sometimes, a PFO might not heal closed. Other times, a closure device can slip out of place and let the PFO reopen. But neither of these events is common.

What can I expect if I have a patent foramen ovale?

Most people with PFO never know they have it because it doesn’t cause any issues. And while PFO can lead to serious, or even life-threatening, events, it’s also a very treatable condition. The outlook for adults and children who need a procedure to close a PFO is generally positive.

People under 25 who have a PFO closure procedure have the same life expectancy as people their age without a PFO. And in people under 40 with symptoms or a high risk of complications, closing a PFO can greatly improve survival chances and quality of life.

Is PFO a serious heart condition?

Most people with a PFO don’t even know they have one because it typically isn’t serious. But for some people, a PFO can lead to serious events like a stroke. If you have a PFO or a family history of them, talk to a healthcare provider. They can tell you more about your risks and offer advice on what to do about them.

How do you treat a PFO in a newborn?

PFO in newborns usually doesn’t need treatment unless it’s causing symptoms. Babies with a severe PFO may need surgery. But for most babies, a PFO will close up on its own before their third birthday.

Does a PFO need to be fixed?

Most PFOs don’t need treatment. It’s usually only necessary if the PFO creates a high risk for or has already caused a serious event.