Presented by Dr. MOHAMMAD ISMET M.B.Ch.B.-C.A.B.M.S.-F.I.B.M.S. Practicing pediatric cardiology
What is a PFO? A patent foramen ovale (PFO) is a defect in the septum (wall) between the two upper (atrial) chambers of the heart. Specifically, the defect is an incomplete closure of the atrial septum that results in the creation of a flap or a valve-like opening in the atrial septal wall. A PFO is present in everyone before birth but seals shut in about 80% of people.
When blood moves directly from the right atrium to the left atrium, this blood bypasses the filtering system of the lungs (the lungs actually do dissolve tiny blood clots). If debris is present in the blood, such as small blood clots, it now passes through the left atrium and can lodge in the brain, causing a stroke, or another organ, such as the heart, eyes, or kidneys.
With each heart beat or when a person with this defect creates pressure inside his or her chest - such as when coughing, sneezing, or straining during a bowel movement - the flap can open, and blood can flow in either direction directly between the right and left atrium.
Symptoms Infants with a patent foramen ovale and no other heart defects do not have symptoms. Although present in about one in five adults, PFOs usually cause no symptoms at all. Far less than 1% has a stroke or other outcome that results in the need to have the PFO closed.
What causes a PFO? The cause of a PFO is unknown. There are no known risk factors. A PFO is congenital, meaning it is a defect that is inborn or exists at birth. Stated another way, the defect is an abnormality, not a disease. The septum between the two atria of the heart developed normally before birth, but the flap did not seal completely after birth.
How is a PFO diagnosed? Frequently a PFO is not diagnosed until a child or adult with this defect has a transient ischemic attack (TIA) - symptoms of a stroke that last for less than 24 hours - or a stroke. Symptoms of a TIA or stroke include any of the following: *Sudden numbness or weakness in the face, arm or leg (especially on one side of the body) *Difficulty speaking or understanding words or simple sentences *Sudden blurred vision or decreased vision in one or both eyes *Difficulty swallowing *Dizziness, loss of balance or coordination *Brief loss of consciousness *Sudden inability to move part of the body (paralysis)
Signs and tests An echocardiogram can be done to diagnose a PFO. If the PFO is not easily seen, a cardiologist can perform a "bubble test." Saline solution (salt water) is injected into the body as the cardiologist watches the heart on an ultrasound (echocardiogram) monitor. If a PFO exists, tiny air bubbles will be seen moving from the right to left side of the heart.
Treatment This condition is not treated unless other heart abnormalities exist or if you had a stroke caused by a blood clot to the brain. Treatment usually requires cardiac cathertization by a specifically trained cardiologist to permanently seal the PFO.
How is a PFO closed using a catheter-based procedure? The catheter is initially inserted into a large vein through a small incision made usually in the inner thigh (groin area) and then is advanced into the heart. One or more tests will be done to measure the PFO and to be sure there are no other defects.
An imaging test called angiography, (an injection of a certain type of dye followed by an x-ray motion picture) may be used to better visualize the heart. An ultrasound imaging technique, to see the defect better and also to determine the size of the closure device needed, may be used. Intracardiac echo (ICE), involves passing an imaging device up to the heart through the vein in the patient’s other leg. Another technique uses an ultrasound probe passed down the esophagus (transesophageal echo, or TEE) to allow to see the heart structures and blood flow as the device is being placed. In addition, a special balloon on a catheter is moved to the area of the hole and inflated across the hole in order to measure the size of the hole when it is gently stretched.
A PFO closure device is moved through the catheter to the heart and specifically to the location of the heart wall defect. Once in the correct location, the PFO closure device is allowed to expand its shape to straddle each side of the hole. The device will remain in the heart permanently to stop the abnormal flow of blood between the two atria chambers of the heart. The catheter is then removed and the procedure is complete.
How does the body react to a permanent implant? The materials used in the closure device products have a proven long-term safety history and have been widely used in heart surgery procedures. It’s not likely that the body will have a negative reaction to these devices. Within a few days, the body’s own tissue will begin to grow over the device. By 3 to 6 months, the device is completely covered by heart tissue and at that point becomes a part of the wall of the patient’s heart.
The patient will not be able to feel the device. The implant will not be affected by airport or other security sensors, or by any household appliances, or medical imaging methods. However, the clarity of medical images may be slightly reduced because of the wire frame on the occluder devices. For this reason, be sure to inform the imaging technician that you or your child has such a device in your heart. You will receive an identification card that should be carried with you/or by your child to show to medical personnel if necessary.