Having a hole in the heart might sound dramatic and alarming, but it's not nearly as uncommon as you might think. Two of the most common reasons to have such a hole are atrial septal defects and a patent foramen ovale (PFO).
What is a PFO?
PFO is not a result of something that happens, but rather something that doesn't — every fetus has a hole between the left and right atria (the two upper chambers of the heart). An essential part of the fetal circulatory system, this foramen ovale allows blood get oxygenated without ever involving the lungs, which don't yet work.
When the foramen ovale does not close after birth, as it does within months after birth in three quarters of infants, it's called a patent ("open") foramen ovale. If the infant doesn't have any additional heart defects, the prognosis is generally very good and treatment may not even be required.
Blood clots and patient foramen ovale: Why this is a risk
Blood clots are a very common problem in the cardiovascular system. They are often filtered out by tiny blood vessels in the lungs. However, since PFO creates a "portal" through which blood can escape the lungs, clots risk being sent on to the rest of the body and even the brain. This, in short, leads to an increased risk of stroke, though strokes are still quite rare in people with PFO.
What are the symptoms of a patent foramen ovale?
PFO doesn't usually cause any symptoms, which is why many people have the condition without even knowing it. In some cases, however, the condition leads to insufficient arterial blood oxygen levels and accompanying shortness of breath.
What are the risks associated with PFO?
Some studies do indicate that patients with PFO are more likely to develop certain diseases, including:
- Migraines. Patients with PFO often suffer from migraines with aura. Despite the fact that these migraines stop when patients have their PFO closed, more studies are needed to figure out if this actually leads to migraine relief.
- Stroke. Patients with PFO have a higher risk of developing stroke because PFO can cause high pressure in the right side of the heart, potentially leading a blood clot to move from the heart to the brain. In fact, for many people, a stroke may be the first sign that they have PFO. People who have a stroke before the age of 55 without a known cause will often turn out to have PFO.
- Heart attack. PFO also increases your risk of having a heart attack. Similar to a stroke, a blood clot may travel from the heart to coronary arteries, causing a heart attack.
- Deep vein thrombosis. Patients with PFO are more likely to develop deep vein thrombosis, a condition in which blood clots form in veins located deep within the body.
What is the cause of PFO?
Scientists don’t know exactly why the foramen ovale doesn’t close in some people. However, genetics are thought to play an important role.
How is PFO diagnosed?
Doctors can use several different tests to diagnose PFO, including:
- Echocardiogram, to create a moving picture of the heart using ultrasound waves. Doctors will likely use a type of echocardiogram called transthoracic echocardiogram to diagnose PFO. A transthoracic echocardiogram uses sound waves that are directed at your heart to develop an image of your heart in motion. Another type of echocardiogram called a transesophageal echocardiogram uses a tube inserted through your mouth and to the stomach. This can help provide a more detailed view of your heart and blood flow.
- Cardiac catheterization, in which a tube is guided to your heart in order to view a detailed image of your cardiovascular system.
How is PFO treated?
Most patients with PFO don’t need treatment to close the foramen ovale closed, but medical intervention is sometimes recommended. A doctor may suggest treatment to close the hole if a patient has:
- Low blood oxygen levels
- Migraines. Though this is not usually recommended, closing the patent foramen ovale potentially liberates patients from debilitating migraines.
- Had a stroke, in order to prevent recurrent strokes.
These are the procedures that can be carried out to close a PFO:
- Device closure, which uses cardiac catheterization to insert a device that helps plug the PFO. The device is located at the end of a long, thin, flexible tube that is put into a vein and guided up using echocardiogram.
- Surgical repair, in which a surgeon closes the PFO by opening up the heart and stitching up the opening. This procedure can now be done by making a very small incision using robotic techniques.
How do you prevent stroke?
Since patients with PFO are more likely to have stroke, doctors may recommend that you go on medication to reduce the risk of blood clots. These include:
- Aspirin
- Clopidogrel
- Warfarin
- Dabigatran
- Apixaban
- Rivaroxaban
- Webster, M. W. I., Smith, H. J., Sharpe, D. N., Chancellor, A. M., Swift, D. L., Bass, N. M., & Glasgow, G. L. (1988). Patent foramen ovale in young stroke patients. The Lancet, 332(8601), 11-12.
- Lechat, P. H., Mas, J. L., Lascault, G., Loron, P. H., Theard, M., Klimczac, M., ... & Grosgogeat, Y. (1988). Prevalence of patent foramen ovale in patients with stroke. New England Journal of Medicine, 318(18), 1148-1152.
- Homma, S., Sacco, R. L., Di Tullio, M. R., Sciacca, R. R., & Mohr, J. P. (2002). Effect of medical treatment in stroke patients with patent foramen ovale: patent foramen ovale in Cryptogenic Stroke Study. Circulation, 105(22), 2625-2631.
- Photo courtesy of SteadyHealth
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