News Review From Harvard Medical School -- Value of Sealing Hole in Heart Debated
Makers of a device that seals a small hole in the heart are being told to prove that it is helpful. Until the studies are done, the U.S. Food and Drug Administration has tightened rules on marketing the devices, the Associated Press reported October 30. About 1 in 5 adults has a small hole in the heart called a patent foramen ovale. Such a hole is present in about 60% of younger adults who have strokes. However, it's not clear if the hole causes strokes or if sealing it prevents strokes. This is what the new studies would show.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

A small hole between the two upper chambers of the heart has caused a big controversy.

Before we are born, all of our oxygen supply comes from our mothers' blood. So it doesn't matter if blood mixes between the two sides of the heart. It's normal for a fetus and newborn baby to have an opening that allows blood to move between the two upper chambers (the atria).

After we are born and need to breathe air to get oxygen, this connection is supposed to close. The heart has its own natural way to fix it. There is a flap on the upper left chamber wall. The pressure is higher in the upper left chamber than in the right chamber. So the higher pressure pushes the flap over the hole. In time, this flap usually gets permanently attached.

However, in 1 out of every 5 of us, the hole doesn't close permanently and completely. The opening is the foramen ovale, and when it stays open it is called a patent foramen ovale (PFO). Many millions of people who have this never know they have it, nor do they need to know.

The potential importance of a PFO was recognized in the 1960s. During this decade, doctors were regularly using ultrasound to take pictures of the heart (echocardiography) for many reasons, one of them to diagnose the cause of a stroke.

Doctors started seeing a higher-than-expected rate of PFO in people with strokes and TIAs (transient ischemic attacks, which can lead to a stroke). This seemed especially true for younger people not at traditional risk of stroke.

This association has led to an acceptance of PFO as a cause of TIA and stroke. The next natural step was to fix the hole either with surgery or by threading a device through the artery to close the hole. But now doctors are not so sure that this always needs to be done.

The waters have grown even muddier. More recently doctors have noticed that people with certain types of migraine (sometimes called complex migraine) also tend to have PFOs. The symptoms of a complex migraine can be just like those of a TIA or stroke.

What Changes Can I Make Now?

If you have complex migraine or symptoms that suggest of a TIA, your doctor may have ordered an echocardiogram as part of the evaluation. So what should you do if you are told you have a PFO?

There is no correct answer. Although it is not likely that the PFO is actually causing your symptoms, the two can have a direct relationship.

Here is one example of a direct relationship. If you have an untreated blood clot in a vein, a piece of that blood clot can break off and travel to the right side of your heart. If there is an opening between the upper right and left chambers, the clot can move across the PFO. It then travels into the lower left heart chamber, where it exits into the aorta. From here, the clot can travel to the brain and cause a TIA or stroke.

In this situation, the person takes blood thinners initially and then has a procedure to close the PFO.

In another example, a person with a PFO who has TIA-like symptoms and blood that clots too easily would be considered for PFO closure.

But most of the time, the situation is not so straightforward. You and your doctor will balance the risks and benefits of the options, usually taking an aspirin or other blood thinner or having the PFO closed.