What is a Patent Foramen Ovale (PFO) Closure Devices?
A patent foramen ovale (PFO) is a normal opening between the two upper chambers of the heart that failed to close after birth. In a normally developing fetus, the foramen ovale allows blood to bypass the lungs. After birth, as the lungs expand and the baby takes its first breath, the pressure changes cause the flap-like tissue separating the left and right atria (the two upper chambers) to close. In about 25% of adults, the flap doesn't always seal tightly leaving a PFO.
Most people who have a PFO don't experience any problems. However, in some cases a Patent Foramen Ovale (PFO) Closure Devices allows blood clots to pass from the right side of the heart to the left side and potentially cause a stroke. The risk is higher for those who have had a stroke or transient ischemic attack (TIA) before the age of 55. PFOs have also been associated with migraines with aura in some studies.
Devices Used to Close a Patent Foramen Ovale (PFO) Closure Devices
For patients who have had a stroke or TIA due to a PFO and have a high recurrence risk, doctors may recommend closing the opening. This can help prevent future blood clots from entering circulation and reduce the risk of another stroke. There are a few different types of PFO closure devices that can be used during a minimally invasive catheter procedure:
- Amplatzer PFO Occluder: This was the first PFO closure device approved by the FDA in 2001. It has nitinol wire panels covered in a fabric that the device expands into a disc shape to close the PFO opening. The panels seal against the heart wall on either side of the PFO.
- Amplatzer Amulet PFO Occluder: An updated version of the original Amplatzer device launched in 2017. It has a similar nitinol frame design but also includes hooks to help anchor it in place and reduce risk of device embolization after implantation.
- Gore CARDIOFORM Septal Occluder: A self-expanding nitinol mesh device covered in PTFE material. One disc is deployed on the left atrial side and another on the right atrial side to close the defect. This was approved by the FDA in 2015.
- Starflex Septal Repair implant: A nitinol single disc device covered in ePTFE material. It has barbs or anchors around the edge to help secure it in the septum wall and prevent movement after implantation. FDA approved in 2018.
- Figulla Flex II PFO Occluder: A self-expanding nitinol mesh device with two discs made of braided nitinol wire that is then covered in ePTFE material. It was approved for use in Europe but did not receive FDA approval in the United States.
How is a PFO Closure Performed?
To close a PFO using one of these implantable devices, doctors perform a catheter-based procedure called percutaneous PFO closure or percutaneous PFO occlusion. The patient is placed under local anesthesia and conscious sedation. Access is obtained through a small incision in the groin area. A catheter is then threaded through blood vessels until it reaches the heart.
The size of the PFO opening is first measured using imaging like transesophageal echocardiography (TEE). The appropriately sized device is then loaded onto a catheter delivery system and threaded through the catheter into the heart. Under TEE and fluoroscopy guidance, the right atrial disc of the device is deployed inside the heart's right atrium. The catheter is then pulled back so the left atrial disc deploys and sandwiches the PFO flap shut between the two discs.
Proper positioning and closure of the defect is confirmed using TEE imaging before removing the delivery catheter. The entire procedure usually takes about an hour. Patients can usually go home the same day and recover for 1-2 weeks with activities limited to prevent device dislodgement as tissue grows over it. Follow up TEE is done to check healing and closure of the PFO at certain intervals after the procedure.
Outcomes and Complications
Multiple randomized controlled clinical trials have shown PFO closure devices to be more effective than medical treatment alone in reducing recurrent stroke or transient ischemic attack (TIA) events among patients who had a previous stroke due to a PFO. On average closure reduced the risk of repeat events by over 50% in studies.
However, PFO closure does carry some risks and potential complications, including:
- Device embolization or dislodgement: Around 1-2% risk the device may detach partially or fully from the septum. This requires percutaneous or surgical removal.
- Arrhythmias: Less than 1% chance of new atrial fibrillation, flutter or other rhythm disturbances after PFO closure.
- Perforation of heart structures: Rare but possible perforation of the atria, ventricle or vessels can occur from catheter, wire or device.
- Infection: Less than 1% chance of infection requiring antibiotics or device removal.
- Bleeding complications: Around 3% risk of significant bleeding or bruising from the vascular access site that requires treatment or transfusion.
- Thrombus formation: Small potential risk of thrombus (blood clot) forming on the device surface that could embolize.
When performed by experienced operators, the rates of major complications are relatively low. But long term device or tissue interactions are still not fully understood given the devices have only been used widely for around 15 years. Ongoing studies continue to evaluate long term safety. For properly selected patients though, PFO closure has become an important treatment option.
PFO closure devices have proven effective in reducing recurrent stroke risk for patients who have experienced an event due to a PFO defect. The minimally invasive procedure can successfully seal the opening between the atria. While complications are possible, outcomes are generally good when performed by experienced heart teams. PFO closure remains an important therapeutic option for select patients.
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Ravina Pandya, Content Writer, has a strong foothold in the market research industry. She specializes in writing well-researched articles from different industries, including food and beverages, information and technology, healthcare, chemical and materials, etc. (https://www.linkedin.com/in/ravina-pandya-1a3984191)
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