What is a PFO and when is it up to closure?
A PFO is a valve-like opening between the right and the left atrium (auricle) of the heart leading to a small intermittent right-to-left shunt inside the heart, the volume of which usually is too small to impair circulation. However, this small shunt can carry small clots along to the arterial side of the heart that may lead to embolic stroke in rare cases. PFOs are inherent in about 25% of the normal population and causes no problems whatsoever except in a tiny minority of individuals. It might be closed if an embolic stroke has occurred and no other causes have been found.
Percutaneous device closure - how does it work?
To further briefly explain what happens in a PFO catheter-based procedure, a cardiac catheterization involves slowly moving a catheter (a long, thin, flexible, hollow tube) into the heart. 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 to and into the heart. 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. 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 communication. The device will remain in the heart permanently to stop any flow of blood between the two atria chambers of the heart. That way, crossing and subsequent embolization of small clots are prevented. An ultrasound imaging technique, called transesophageal echocardiography (TEE), is used to check for adequate device position at the very end of the procedure. Once a good result has been confirmed the catheter is removed and the procedure is complete.
How long does the procedure take?
The cardiac catheterization procedure for a PFO closure typically takes about 30 minutes to complete. A local anesthetic is used to numb the right groin area where the catheter is inserted. Use of sedation is mandatory for the TEE at the end of the procedure.
What is a PFO closure device and how does it work?
The preferred type of PFO closure devices are currently being used at the Cleveland Clinic Abu Dhabi is the Amplatzer® PFO Occluder System consisting of two attached circular discs - a larger disc, which will reside facing the right atrium, sandwiched on top of a smaller disc, which will face the left atrium. These discs are made of polyester fabric encased by a wire mesh made of a nickel-titanium metal alloy. (Figure: Amplatzer® PFO Occluder. Image, with permission, from AGA Medical Corporation, St. Jude Medical.)
How does the body react to this permanent implant?
The material used in the occluder, an alloy containing nickel, has a proven long-term safety history and have been widely used in medicine. 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 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. Ectopic heartbeats (extrasystoles) can occur days and weeks after implant. Usually, they can be treated medically if needed. Extrasystoles disappear with progressing ingrowth of the device after 6 to 8 weeks.
The implant won’t be affected by airport or other security sensors, or by any household appliances, or medical imaging methods. However, the clarity of MRI or CT 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 have such a device in your heart. The device can also be seen on chest X-ray. You will receive an identification card that should be carried with you to show to medical personnel if necessary.
Who is a good candidate for this type of valve replacement?
PFO closure devices can be used:
- If the patient has no blood clots in his/her heart
- If the patient does not need surgery to fix other heart defects
- If the patient has no bleeding disorder, untreated ulcer, and is able to take aspirin and clopidogrel
- If the patient has no active infection anywhere in the body (the device can be implanted not until any infection is completely gone)
Your doctor/neurologist will discuss alternative treatment options including long-term antiplatelet drug treatment.
How does long-term drug treatment compare to PFO device closure?
The catheter-based procedure for PFO closure could not be demonstrated superior to long-term drug treatment by multicenter trials. Individual anatomic characteristics as are size of the communication and coincident aneurysm of the interatrial septum as well as recurrent stroke make the PFO more probable to be the culprit source of embolism. For that reason, decision is made on an individual basis.
Your doctor will prescribe medications that will need to be taken at home. Aspirin will need to be taken daily for six months and clopidogrel for three months. Antibiotics will also need to be taken one hour before certain medical procedures (for example, dental cleaning/dental surgical procedures as well as certain surgeries) for up to 6 months post device placement. Your doctor will provide information on which procedures will require antibiotic pre-treatment. As with all medications, take them only as directed by your doctor, never stop taking the medication without talking with your doctor first, and call your doctor if you experience unpleasant reactions or have any concerns about the medication. Finally, a follow-up return trip to the hospital will be necessary at 6 months to monitor the patient’s heart and ingrowth of the device. The visit will include an electrocardiogram and TEE. The patient needs to fast prior to this visit.