PFO closure is a minimally invasive heart procedure that seals a small hole between the upper chambers of the heart. The hole, called a patent foramen ovale (PFO), is a leftover opening from fetal development that never closed after birth. About 1 in 4 people have one without knowing it, and most never need treatment. But for people who’ve had an unexplained stroke, closing the PFO with a catheter-delivered device can cut the risk of another stroke roughly in half.
Why the Hole Exists
Before birth, every baby has a small opening called the foramen ovale between the left and right upper chambers of the heart (the atria). This opening lets blood bypass the lungs, which aren’t yet in use. After birth, once a baby starts breathing, the opening typically seals shut on its own. When it doesn’t, it’s called a patent foramen ovale, meaning the passage remains open.
A PFO isn’t the same as a full hole in the heart. It’s more like a flap that can open under pressure, allowing blood to pass from one side to the other. Most people with a PFO never experience symptoms and never need treatment. The concern arises when a blood clot from the veins slips through that flap, bypasses the lungs (which normally filter out small clots), and travels to the brain. This can cause an ischemic stroke with no other identifiable cause, known as a cryptogenic stroke.
Who Qualifies for Closure
PFO closure isn’t offered to everyone with this opening. Current clinical guidelines focus on adults between 18 and 60 who have already had a cryptogenic stroke. Doctors use scoring systems like the RoPE score and the PASCAL Classification to determine whether the stroke was likely related to the PFO or caused by something else entirely.
The PASCAL system sorts patients into three groups: probable, possible, and unlikely PFO-associated strokes. Roughly 6 out of 7 patients fall into the probable or possible categories and are likely to benefit from closure. The remaining 1 in 7, those classified as unlikely, may actually be harmed by the procedure because their stroke probably had a different cause, and closure would expose them to procedural risks without meaningful benefit. High-risk anatomic features of the PFO itself, such as a larger opening or an associated membrane called an atrial septal aneurysm, also factor into the decision.
How the Procedure Works
PFO closure is performed through a catheter, meaning there’s no open-heart surgery. The entire procedure is done through a small puncture in a vein near the groin. A thin, flexible tube is threaded up through the vein, into the right side of the heart, and across the PFO into the left atrium. Imaging and pressure measurements confirm the catheter is in the correct position.
Once the catheter is in place, the closure device is delivered through it. The most widely used device is a self-expanding double-disc occluder made from a nickel-titanium alloy mesh with thin polyester fabric sewn inside to help seal the opening. The left-side disc opens first and is pulled snug against the wall separating the atria. Then the right-side disc deploys, sandwiching the tissue between the two discs. After release, doctors use imaging and a bubble study (injecting agitated saline to look for bubbles crossing between chambers) to confirm the device is seated properly and no blood is leaking through.
The procedure typically takes about an hour. You’re given blood-thinning medication during the procedure to prevent clotting, and supplemental oxygen as a precaution.
What Recovery Looks Like
Recovery is quick compared to most heart procedures. You’ll stay in bed for about six hours afterward and can usually go home the same evening or the next morning. Most people return to regular daily activities within a week, though there are a few specific restrictions to follow:
- Driving: wait at least two days
- Light lifting (over 10 pounds): avoid for one week
- Strenuous exercise or heavy lifting (over 20 pounds): wait one month
After the procedure, you’ll be prescribed blood-thinning medication, most commonly aspirin. The standard course runs at least six months, which is roughly how long it takes for the body’s own tissue to grow over the device and fully incorporate it into the heart wall. A study tracking patients for 10 years found that stopping blood thinners at the six-month mark did not increase the risk of recurrent stroke or clot formation on the device. Some doctors prescribe longer courses, but the evidence suggests six months is sufficient for most people.
How Well It Prevents Stroke
A landmark trial published in the New England Journal of Medicine followed patients with cryptogenic stroke for an extended period and found that PFO closure cut the rate of recurrent stroke by 45% compared to medication alone. Among patients who received closure, strokes occurred at a rate of 0.58 per 100 patient-years, versus 1.07 per 100 patient-years with medical therapy only.
The benefit was even more pronounced for strokes that remained unexplained. These recurred at a 62% lower rate in the closure group, suggesting that the procedure is most effective when the original stroke was genuinely caused by a clot passing through the PFO. This is why patient selection matters so much: the better the match between the PFO and the stroke mechanism, the greater the protection closure provides.
Risks and Complications
PFO closure is generally safe, but it carries one notable risk: new-onset atrial fibrillation, an irregular heart rhythm. Clinical trials have reported this occurring in roughly 2% to 12% of patients. A smaller study using continuous heart monitors (implantable loop recorders) detected a higher rate of 26%, suggesting that many mild or brief episodes go undetected in studies relying on standard monitoring. Most of these episodes occur within the first six months, likely triggered by the device pressing against heart tissue before it’s fully healed over.
Serious procedural complications like bleeding around the heart (pericardial effusion) or blood clots in the leg veins are rare. The groin puncture site can develop bruising or minor bleeding, but significant vascular complications are uncommon with experienced operators. The device itself has a very low rate of clot formation, around 0.2% per patient-year in long-term follow-up, particularly once tissue has grown over the mesh.
Life After the Device
Once the device is in place and tissue has covered it, most people don’t feel it or think about it. The nickel-titanium alloy is MRI-compatible, so future imaging isn’t a concern. You’ll have follow-up echocardiograms to confirm the device is seated properly and no residual shunting remains. After the initial recovery period and the six-month course of blood thinners, most patients return to a fully normal life with no ongoing restrictions. The device stays in permanently and doesn’t need replacement.