Patent Foramen Ovale (PFO)

A patent foramen ovale (PFO) is a hole between the heart’s upper chambers (the left and right atria) that failed to close after birth.

The small, flap-like opening — known as the foramen ovale — exists in everyone prior to birth. Shortly after birth, the opening typically closes. When it doesn't close, which happens in approximately a quarter of the population, the opening is called a patent foramen ovale.

Most individuals with a PFO never know they have it because signs or symptoms are typically rare. In fact, a patent foramen ovale is often discovered during tests for other health conditions and for most people does not need to be treated.

The Connection Between PFO and Other Conditions

Although a PFO is not generally cause for concern, some studies indicate the condition is more common in those who experience unexplained strokes or migraines with aura.

Most often it is found that the cause of an individual’s stroke or migraine is due to other health issues, not a PFO. The fact that the person has a PFO is merely a coincidence. In some cases, however, the PFO is responsible as small blood clots in the legs or heart move through the small hole and block blood flow to the brain, resulting in a stroke.

Research suggests that closure of a PFO in carefully selected patients with a history of stroke and PFO can reduce the risk of a recurrent stroke. However, studies of PFO closure in patients with migraines show no significant reduction in headache symptoms.

For more information about stroke, visit our Stroke Treatment at the Frankel Cardiovascular Center on, or our Stroke page on

PFO Expertise

The decision to close a PFO is based on a patient’s risk factors for stroke or on whether the patient has actually experienced a stroke or transient ischemic attack (TIA). Transient ischemic attack, or TIA, is a temporary blockage of blood flow to the brain, also known as a mini stroke. For this reason, patients at Michigan Health undergo a thorough evaluation by experts in stroke neurology and interventional cardiology. Together, this experienced team offers collaborative care through the Michigan Health Comprehensive Stroke and PFO Program.

For patients who have had a stroke or TIA and who also have a PFO, our team provides a thorough diagnostic evaluation by a vascular neurology specialist and an interventional cardiologist to determine if the PFO was a potential cause for the stroke and whether other causes might exist (e.g., heart attack, irregular heartbeat).

We then work with the patient to develop a personalized treatment plan and provide individualized counseling to help the patient understand their neurological and cardiac conditions as well as how to reduce the risk of another stroke.

Patients may schedule appointments with a Michigan Medicine neurologist and cardiologist on the same day or may be seen on separate days. Virtual visits are also available.

Diagnosing Stroke Risk

Not all patients with a PFO are at risk for a stroke from the PFO. However, patients who have experienced a stroke require a thorough stroke evaluation. Common causes of strokes in older adult patients include heart disease and cholesterol buildup in the blood vessels going to the brain or within the brain. Patients who have a stroke will undergo evaluation for these common causes.

Heart Conditions That Increase Stroke Risk

The most common heart condition that increases the risk of stroke is an irregular heartbeat, called atrial fibrillation. Stroke evaluation may include a short-term heart monitor to evaluate for this abnormal rhythm. Other heart conditions that increase the risk of stroke include a recent heart attack or abnormalities of the valves in the heart. This may be evaluated with a heart ultrasound.

Blood Vessel Conditions That Increase Stroke Risk

The most common blood vessel condition that increases the risk of stroke is atherosclerosis, or cholesterol buildup of the blood vessels leading up to the brain and within the brain itself. To evaluate for this, a CT, MRI or ultrasound may be performed to take a closer look at the blood vessels from the heart to the brain.

Stroke Evaluation in Younger Patients

In younger patients without typical risk factors for stroke, evaluation may include lab tests to identify abnormal blood clotting disorders that increase the risk of blood clot formation.

If these evaluations fail to identify a typical cause or typical risk factors for the stroke, a PFO may be considered as a potential cause in the right setting.

How Is a PFO Treated?

Extensive research has shown that not all patients with a PFO require the PFO be closed. Among carefully selected stroke patients with a PFO, there was a reduction in recurrent stroke after closure. Stroke as a result of PFO is relatively uncommon and is the reason a thorough evaluation of potential stroke risk factors is important prior to a decision to close a PFO.

Once it is decided to close the PFO, a careful review of cardiac imaging studies is done. The majority of PFOs can be closed via minimally invasive or percutaneous catheter-based techniques. A catheter-based closure is done through the femoral vein in the leg. The catheter is inserted into the femoral vein and a closure device is guided through the catheter up to the heart with the imaging assistance of an echocardiogram and x-ray. Once in place, the device is opened and the PFO is sealed. Most PFO closure procedures can be performed under light or moderate sedation and require an overnight stay in the hospital.

In rare cases, a PFO closure may require an open surgical procedure in which the heart is opened and the PFO is stitched shut.


Michigan Medicine is involved in ongoing PFO research and is also home to a registry for patients over 60 with stroke and PFO to help inform treatment.

Make an Appointment

To make an appointment at the Comprehensive Stroke and PFO Program, call us at 888-287-1082 or visit our Make a Cardiovascular Appointment page for more information about what to expect when you call us.