Heart Defect PFO

The oxygen supply of a child in the womb is independent of the lungs. Therefore the blood flow is deviated and the lungs are bypassed by a connection between the two atria. This connection is called the foramen ovale. After birth, the child starts to breathe independently and the connection between the atria closes. In as many as 1 out of 4 people the atria does not close properly, and a trap-door-like opening a few millimeters wide is left open, known as a Patent Foramen Ovale (PFO). 

As the PFO is constructed like a trap-door, the opening is normally closed, since the pressure in the left atrium is higher than in the right atrium and this pressure closes the lid of the door. However, when the pressure on the right side of the heart increases and becomes much higher than the pressure on the left side of the heart, the trap-door will be pushed open. This may occur in situations with heavy pressure development inside the chest, such as gasping for breath, coughing or sneezing, or with chest infections. Other typical examples are lifting a heavy weight or even when diving.

PFO

When the door is pushed open, oxygen-poor blood from the right heart (venous) side may mix with oxygen-rich (arterial) blood from the left heart side. Unfortunately, there are usually many small blood clots in the venous system arising from smaller injuries as well as low flow conditions when patients do not move for several hours (e.g., sitting in an airplane, etc.). These blood clots are normally transported with the blood stream into the lungs, filtered there and finally resolved. If, however, pressure in the lungs rises, a clot can then come from the right atrium into the left atrium, which would otherwise remain stuck in the filter system of the lungs. This is called a paradoxical embolism. Such clots can be the cause of an occlusion of a small blood vessel, and if this occlusion happens in the brain it can cause a stroke.

As many as 25% of all people have a PFO. Infants with PFOs have no symptoms if they do not have other heart defects. Unless there are other defects, there are usually no complications from a PFO, and the situation is similar in adults. Adults or older people however may suffer more frequently from clotting disorders based on risk factors typical for older age (i.e., smoking, obesity, hormonal contraception (“the pill”, high blood pressure, arteriosclerosis, etc.) Therefore adults with a PFO may have a higher risk of getting certain types of strokes, namely a stroke via a paradoxical embolism. In these circumstances, medication to prevent blood clots can be advantageous.

Once a person has had a stroke caused by a clot in the brain, and a PFO is diagnosed with the likelihood of a paradoxical embolism, a closure of the PFO is recommended to avoid future strokes.

Closure of PFO

Once the diagnosis of a PFO responsible for paradoxical embolism is made, it is time to close it. Today, in nearly all patients with a PFO, closure can be achieved without open-heart surgery but by using interventional catheterization.

Interventional closure:  the closure is performed in a cardiac catheterization laboratory, known as a cath lab. Techniques vary between clinics and physicians active in catheter intervention. The procedure can be done under local anesthesia, with the support of sleeping medication (sedation) or by general anesthesia and will be performed by a (pediatric) cardiologist. A thin tube, i.e., a catheter, is inserted into a blood vessel in the groin and guided to the heart. The exact size of the PFO is usually measured by ultrasound transesophageal echography (TEE) or intracardiac echography (ICE) and the surrounding tissue is assessed. In many PFO cases, the size of the defect can be measured exactly by inserting a soft balloon. This is known as ‘balloon sizing’. Everything is constantly controlled through an X-ray, and the thin tube, i.e., the catheter, is exchanged for a larger catheter; the delivery sheath.

The appropriate PFO occluder is pushed through to be placed across the hole, through the delivery sheath. The occluders consist of a left-sided disc and a right-sided disc. The left-sided disc is deployed first and then retracted directly to the septum, followed by the right-sided disc being deployed and sealing the defect between the two discs. Once the device is in the correct position, the physician will release the device and withdraw the delivery sheath. The defect is now closed and the tissue will grow around the device and ultimately become a permanent part of the septum.  This procedure takes approximately 60 minutes.

Occluders and airports

The device will not set off any metal detectors at an airport security scan. 

If you have additional questions or need additional information, please contact Occlutech’s service center via email: order@occlutech.com

Airport

PFO Procedure

Patent Foramen Ovale

A heart with a PFO defect
A Patent Foramen Ovale (PFO) is an opening or trap-door between the right and left atrium. Usually this opening is closed but it can open in situations with elevated blood pressure in the right side of the heart. 

Closing the PFO defect
The closure is performed in a cardiac catheterization laboratory, a cath lab. A thin tube, i.e., a catheter, is inserted into a blood vessel in the groin and guided to the heart. The size of the PFO is measured by ultrasound (TEE, ICE) or with a balloon catheter. The catheter is then exchanged for a larger catheter; the delivery sheath. A PFO occluder is pushed through to be placed across the hole through the delivery sheath. Once the device is in the correct position and firmly attached on both sides, the physician will release the device and withdraw the delivery sheath. 

Occlutech PFO device in position
The device is now in the correct position and the defect is closed by the device’s two discs. After a few months, the occluder will be covered by a thin layer of cells, then covered by the tissue of the heart and over time the defect will be completely overgrown. Only an X-ray and ultrasound (ECHO) will show that an occluder is implanted.

Animation showing the mechanism of a PFO related cryptogenic stroke in a general way.

Language versions

Animation showing how an Occlutech PFO Occluder is implanted in a general way.

Language versions

Occlutech PFO Occluder

The Occlutech device used to close a PFO defect is called the Occlutech PFO Occluder. The device is made of braided Nitinol threads. Nitinol is a very elastic alloy with wide-ranging memory skills. The superelasticity effect helps the device to go back into its “programmed” shape after being deformed, a Nitinol device can be folded to be guided to its intended place of implantation. The device will be pushed through the delivery catheter across the defect, then both discs will fix the device at the septum wall and the device will then be released when placed in the correct position to close the defect. This helps stop the blood going through the meshwork of the device.1

2023-06-19_Occlutech_PFO_PUB_6
Not approved or available for sale in the United States. Product(s) may not be available in all markets because product availability is subject to the regulatory and/or medical practices in individual markets. Please contact your Occlutech representative if you have questions about the availability of Occlutech products in your area.
Content references:
  1. HildickSmith, D. et al. Occlutech percutaneous patent foramen ovale closure: Safety and efficacy registry (OPPOSE). Int J Cardiol 245, 99104 (2017)
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