A PFO closure is a minimally invasive heart procedure that seals a small opening between the upper chambers of your heart. This opening, called a patent foramen ovale, is a leftover from fetal development that never fully closed on its own. About 25% of people have one and never know it. But in certain cases, particularly after an unexplained stroke, closing it can significantly reduce the risk of another one.
What a PFO Is and Why It Exists
Before birth, every baby has a small opening called the foramen ovale between the right and left upper chambers of the heart. This opening serves an important purpose: because a fetus doesn’t breathe air, there’s no reason to send blood to the lungs. Instead, oxygen-rich blood from the mother flows through the placenta, enters the baby’s heart on the right side, and passes through the foramen ovale directly to the left side, where it gets pumped out to the body.
After birth, the pressure changes from breathing normally force this flap-like opening to seal shut. In most people it fuses permanently. But in roughly one in four people, the flap never fully closes, leaving a patent (open) foramen ovale. Most of the time, the flap stays pressed shut by normal blood pressure and causes no problems at all. The concern arises when pressure changes (coughing, straining, even sneezing) briefly open the flap and allow blood to cross from the right side to the left without passing through the lungs first. If that blood carries a small clot, it can travel straight to the brain and cause a stroke.
Why Doctors Recommend Closing It
PFO closure is primarily performed to prevent a second stroke in people who have already had one with no identifiable cause. These unexplained strokes are called cryptogenic strokes. The logic is straightforward: if a clot slipped through the PFO and caused the first stroke, sealing it shut should prevent that from happening again.
Not everyone with a PFO and a history of stroke benefits equally. Doctors use a classification system called PASCAL to sort patients into three groups based on two factors: the size and features of the PFO itself, and a scoring tool (the RoPE score) that accounts for age, blood pressure history, diabetes, smoking, and characteristics of the stroke on brain imaging. Patients classified as “probable” candidates, meaning they have a large PFO and a high RoPE score, see the greatest benefit: roughly a 90% relative reduction in recurrent stroke compared to medication alone. Those in the “possible” category still see a meaningful 62% relative reduction. For patients in the “unlikely” category (small PFO, lower RoPE score), closure doesn’t offer a clear advantage over blood-thinning medication.
Current guidelines focus on adults younger than 60 who have had a cryptogenic stroke. For patients over 60, the evidence is limited because clinical trials haven’t specifically studied this group. Older patients are typically monitored with extended heart rhythm tracking to rule out atrial fibrillation, which is a more common stroke cause in that age range.
How a PFO Is Diagnosed
The standard way to detect a PFO is a “bubble study.” A technician injects a small amount of agitated saline (essentially tiny bubbles mixed into saltwater) into a vein while performing an ultrasound of the heart. Normally, the lungs filter out all the bubbles before the blood reaches the left side of the heart. If bubbles appear on the left side, it means blood is crossing through an opening like a PFO.
This test can be done with a standard echocardiogram through the chest wall, which catches about 73% of cases. For a more definitive answer, doctors use transesophageal echocardiography, where a small ultrasound probe is guided down the throat to get a much closer view of the heart wall. This is considered the gold standard and is typically performed before proceeding with closure, since it can also measure the size of the opening and check for other structural features that affect treatment decisions.
What Happens During the Procedure
PFO closure is a catheter-based procedure, meaning there’s no open-heart surgery involved. You’ll be given sedation or general anesthesia. A doctor makes a small puncture in a blood vessel in your groin and threads a long, thin tube (catheter) through the vein up to your heart. At the tip of the catheter is a small closure device, most commonly the Amplatzer PFO Occluder, which is the FDA-approved device designed specifically for this purpose.
Once the catheter reaches the PFO, the doctor positions the device so that it straddles the opening, with one disc on each side of the heart wall, essentially sandwiching the flap shut. The device locks into place, the catheter is withdrawn, and a bandage covers the small puncture site in your groin. Over the following weeks, heart tissue grows over the device, permanently incorporating it into the wall between the chambers. The entire procedure typically takes about an hour.
How Effective Closure Is
A large meta-analysis tracking over 3,600 patients for an average of nearly four years found that PFO closure cut the rate of recurrent stroke roughly in half compared to medication alone. The stroke recurrence rate dropped from about 1.1 per 100 patient-years with medical therapy to 0.53 per 100 patient-years after closure. In absolute terms, about 47 patients need to be treated to prevent one stroke over that time frame. That may sound modest, but for a younger person facing decades of stroke risk, the cumulative benefit grows substantially over a lifetime.
Risks and Complications
The most notable complication is new-onset atrial fibrillation, an irregular heart rhythm that can itself increase stroke risk. In clinical trials, this occurs in roughly 2.8% to 5% of patients, usually within the first few weeks after the device is placed. Longer-term studies tracking patients for eight to nine years report rates of 6% to 7.6%. Most episodes are temporary and resolve on their own or with treatment, but it’s an important tradeoff to discuss beforehand.
Other risks are typical of catheter-based heart procedures: bleeding at the groin site, blood vessel damage, infection, or the device shifting out of position (rare). Serious complications are uncommon, but the upfront procedural risk is part of why doctors carefully select which patients are likely to benefit enough to justify closure over medication alone.
Recovery and What Comes After
Recovery is quick. You’ll rest in the hospital bed for about six hours after the procedure and typically go home the same evening or the next morning. Walking is fine right away, though at a relaxed pace. You can drive again after two days and return to most regular activities within a week. The main restrictions: avoid lifting anything over 10 pounds for the first week, and wait a full month before strenuous exercise or lifting 20 pounds or more.
After the procedure, you’ll take two blood-thinning medications (typically aspirin and clopidogrel) for one to six months. This dual regimen prevents clots from forming on the device while tissue grows over it. After that initial period, you’ll continue on aspirin alone for up to five years. Follow-up imaging confirms the device is seated properly and that the opening has sealed completely.