What is a Patent Foramen Ovale?
The Foramen Ovale is an opening between the upper chambers of the heart called the right and left atria. This connection is necessary during fetal life but normally closes soon after birth. Sometimes it does not close, but remains open after birth and through life. If this happens, the result is called a patent foramen ovale or PFO. Typically it does not cause an immediate problem. A PFO is something like a flap valve between the upper chambers of the heart that usually remains closed and functions normally. However, sometimes it can open with pressure shifts in the heart chambers. For example, bearing down during child birth or bowel movements can cause the PFO to flap open. Many individuals may have a PFO and never know it. PFOs are not repaired unless they become symptomatic or are implicated in a stroke.
PFO and Stroke
Doctors believe that in some instances PFOs may be the cause of some types of strokes because they allow a small amount of blood to circulate directly from the right atria to the left, bypassing the lungs. The lungs act as a filter to remove small clots from the blood stream. If these clots bypass the lungs and get into the general body circulation they can block blood flow to the brain and cause a stroke.
Diagnosing and Repairing a PFO
Diagnosing a PFO is done by using a transesphogeal echocardiogram along with a bubble study. During this procedure agitated saline is inserted into the upper right chamber of the heart and using echocardiography a physician can determine if the bubbles are passing directly into the left atria. If so, this means that a PFO is present. If the PFO is thought to be a danger to the patient, a physician will recommend closing it.
Treatment of PFO
Traditionally, surgery has been required to close a PFO. This requires a major incision through the breastbone, and a 3-4 day hospitalization. In the past 2 years, a less invasive method has been developed.
IHI’s own Dr. Mark Sanz is experienced in repairing PFO using the less invasive cardiac catheterization technique. An implant is used to cover the flap and prevent blood from flowing across the border between the right and left atria. In the cath lab the patient will have a catheter inserted into the groin area. This catheter allows the physician access to the heart chambers. After careful measurements have been taken to ensure that the implant fits the PFO, the implant can be delivered to the heart via the catheter in the groin. When the implant reaches the PFO one side can be opened and pulled snug up against the border that divides the heart chambers. The other side can then be placed and the flap valve can no longer open, regardless of the pressure in the heart system. It is like opening two tiny umbrellas and pulling them tightly together. The implant is made of a small metal frame covered with a special fabric that promotes the growth of new tissue. This procedure avoids general anesthesia and a major incision. The patient may be in the hospital for 1-2 days.
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