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What is a PFO?What is an ASD?What is a VSD?
A patent foramen ovale, or PFO, results from an incomplete closure of the atrial septum. This type of defect is transient, meaning it is present only under certain conditions. Typically, this defect works like a flap valve, and opens up when the patient creates more pressure inside their chest. This is called a Valsalva maneuver, and can occur when people cough, sneeze, or strain. If the pressure is enough to open the defect, blood can flow from the right atrium to left atrium. If there are debris or chemicals (i.e.: serotonin) present in the blood at the site of the defect and crosses it, this material may travel to the arterial circulation and into the coronary arteries causing a heart attack or to the brain causing a stroke, transient ischemic attack (TIA), or triggering a migraine.
What is PFO?How does a PFO affect the body?What are the treatment options for a PFO?Is surgery an option for PFO?How does an implant differ from surgery to close a PFO?What are the Advantages of BioSTAR®, STARFlex® and CardioSEAL® to close a PFO?
What is PFO?
The foramen ovale is a small opening located on the atrial septum that is used during fetal circulation to speed up the travel of oxygenated blood through the heart. When in the womb, a baby does not use its own lungs to oxygenate blood; it relies on the mother to provide oxygen rich blood from the placenta through the umbilical cord. Normally the foramen ovale closes at birth when increased blood pressure on the left side of the heart forces the opening to close.
If the atrial septum does not close properly, it is called a patent foramen ovale. This type of defect generally works like a flap valve, only opening during certain conditions when there is more pressure inside the chest. This increased pressure occurs when people strain while having a bowel movement, cough, or sneeze.
How does a PFO affect the body?
If the pressure is sufficient, blood may travel from the right atrium to the left atrium. If there is a clot or particles in the blood traveling in the right side of the heart, it can cross the PFO, enter the left atrium, and travel out of the heart to the brain (causing a stroke) or into a coronary artery (causing a heart attack).
A stroke occurs when circulation to a part of the brain is blocked. The resultant lack of oxygen can cause problems that range from death to permanent or temporary affects on muscle control and body function.
A PFO does not cause a stroke, but its presence may be a pathway for a stroke to occur by allowing blood to flow from the venous system to the arterial system without going through the lungs first. One of the important functions of the lungs, in addition to oxygen exchange, is to filter debris from the venous blood returning to the heart. If this debris goes to the arterial circulation, it can lodge in an artery serving the brain, heart, or other major organ causing an arterial embolization. When it lodges in the brain, a stroke occurs. If the effects of the stroke last less than 24 hours, the stroke is called a Transient Ischemic Attack (TIA). If the symptoms persist longer than 24 hours, it is termed a stroke.
What are the treatment options for a PFO?
In patients for whom the patent foramen ovale has been demonstrated to open, the current standard of care is blood thinners. These drugs, including Coumadin (Warfarin), Aspirin or Plavix, thin out the blood or keep it from sticking together and hopefully reduce the risk of a clot.
There are complications associated with the chronic use of blood thinners, such as ulcers, internal bleeding, cerebral bleeding, hematuria, and hemorrhoidal bleeding. Quality of life is often affected as patients on chronic blood thinners must be careful to avoid injuries which may cause bleeding.
Recently, some neurologists and cardiologists have recommended that PFO's be closed. Surgical closure of a PFO is not often advocated because of the risks associated with open heart procedures, however the desire to close PFO's is gaining significant interest, as it potentially eliminates the need to continue with long-term anticoagulants and may reduce the risk of a recurrent stroke or TIA.
Transcatheter closure of a Patent Foramen Ovale (PFO) has been proved safe with thousands of implants. The long term benefits are currently being studied in clinical trials in the United States.
Is surgery an option for PFO?
Having open heart surgery to stitch the PFO close is one option. Open heart surgery for PFO closure is a major, invasive procedure which generally follows this sequence:
Open heart surgery is considered major surgery and carries with it some significant complications. Those include:
In addition, the surgery does not always result in total closure of the defect.
If you are considering surgery, ask your surgeon or cardiologist for specific information about the results of the surgery at your hospital. Generally, surgery requires 4 - 7 days in the hospital in uncomplicated cases, and 4-6 weeks of recovery at home prior to returning to full, normal activity. Pain can be significant, and pain management is routinely provided during the post operative and recovery phase.
How does an implant differ from surgery to close a PFO?
Transcatheter Repair
One option for repair if medical therapy fails is the percutaneous placement of a septal defect repair implant which provides the following advantages over open heart surgery.
Although not medically important, many parents and patients also indicate that the cosmetic benefit of avoiding a major scar on the chest is an important consideration, particularly in children and young adults.
As with all medical procedures, there are risks and potential complications associated with procedures used to deliver implants. Perhaps most importantly, the risk of a patient having a recurrent stroke or TIA with an implant has not been proven in any comparative way to medical therapy.
All of these complications have been reported through the years from different types of septal implants.
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What are the Advantages of BioSTAR®, STARFlex® and CardioSEAL® to close a PFO?
We believe that the BioSTAR®, STARFlex®, and CardioSEAL® implants have a distinct advantage over other PFO closure devices. We have the longest clinical use history, our designs are highly conformable, atraumatic, low septal profile, low metal surface area, and provide a scaffold proven to promote endothelialization. CardioSEAL® was the first generation of septal closure device to incorporate elbow coils which allow the device and future generations to be compliant with the septal surface and motion. STARFlex® has a self-adjusting PFO-compatible centering mechanism which provides exceptionally high closure rates. BioSTAR® our newest bioabsorbable device will provide even more biological response by promoting quicker healing and device endothelialization, improving both PFO closure rate and patient safety.
Since 1986, NMT Medical, Inc. has worked with physicians to pioneer innovative, catheter-based technologies to provide a minimally invasive treatment for a range of cardiac defects, such as Patent Foramen Ovale (PFO), atrial septal defects (ASD) and ventricular septal defects (VSD). NMT developed the first implants ever to be used for these applications and was the first company to receive regulatory approvals in the USA and Europe. There are now over 27,000 NMT septal repair implants successfully implanted worldwide and clinical experience (including earlier generation implants) dates back over 10 years. NMT is committed to developing and manufacturing products of the highest quality which meet a number of exacting criteria, including:Conformability – the majority of the surface area of the CardioSEAL® and STARFlex® implants is Dacron® fabric. The low profile of the device and smooth transition between the frame and fabric surface are designed to conform to individual patient anatomy.
Biocompatibility – the inherent porosity achieved by selecting a knitted design (CardioSEAL® and STARFlex®) enhances the integration of tissue ingrowth into the fabric, thus promoting uniform and smooth endothelialization. BioSTAR® employs a highly purified, bioabsorbable, Type I, porcine collagen which is replaced over time by natural tissue.
Minimal metal mass – by using only a low-profile, metal framework with a series of flexible “arms,” all NMT Medical implants minimize the risk of damage to the heart tissue. There are no known cases of nickel allergy using NMT devices.
Durability – designed to last a lifetime, NMT devices only use materials with proven clinical experience as permanent implants.
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"Over time the BioSTAR® scaffold will be replaced with the patient's native tissue."
Michael J. Mullen, MB, BS, MRCP, MD, Consultant Cardiologist, The Heart Hospital, London, United Kingdom