| Stroke and PFO |
Stroke is the third leading cause of death in the United States. One million people suffer from stroke each year.
Stroke is the major cause of disability in the United States. There are 5 million survivors of stroke in this country.
Stroke is not rare in young people under 50 years of age accounting for 5% of all strokes.
Until recently, 40% of all strokes were of unknown cause. We now know that most of these unexplained strokes are caused by a PFO. |
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| What is a PFO? (Patent Foramen Ovale) |
During formation of the heart in the fetus, two pieces of the wall grow to overlap each other to divide the upper chambers (atria) of the heart into right and left chambers.
Before birth, the lower divider acts as a flap or tunnel which allows blood to flow from the right side of the heart to the left side. This blood flow contains oxygen from the mother’s placenta.
After birth, right to left blood flow is no longer needed. The two dividers of the right and left atria fuse to form a solid wall (septum). The septum is fused in 90% of people by 18 months of age.
However, the dividers which form the septum do not fuse in 10% of people leaving a flap or tunnel which may open and close as right heart pressure changes.
This opening (flap or tunnel) is the Patent Foramen Ovale or PFO. |
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| Why PFO cause strokes |
In the normal adult heart, the right and left sides are completely separated.
Blood from the body enters the right atrium and flows to the lungs.
Filtered blood from the lungs carries oxygen and is pumped to the brain and organs of the body.
With a PFO present, blood from the body can bypass the lungs and travel to the left side of the heart.
In the normal heart (no PFO), a blood clot from the body would be stopped in the lungs.
But if a clot crosses the PFO, it can go to the brain causing a stroke.
Where do blood clots come from to cause stroke in patients with a PFO?
Blood clots may form in the veins in the legs, break lose, and travel with blood flow to the heart. These clots may pass through the PFO causing a stroke.
Or, blood trapped within the PFO flap or tunnel for a period of time may clot.
When increased pressure in the right heart opens the flap of the PFO, the clot may dislodge and travel to the left side of the heart and then to the brain. |
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| How are PFO diagnosed? |
| Transthoracic Echo |
Heart disorders are the most common cause of stroke.
TransThoracic Echocardiography ( or TTE) is a noninvasive, ultrasound test which evaluates heart structures. Microscopic bubbles injected into a vein show a PFO when they cross to the left side.
TTE is about 60% reliable in finding a PFO.
Although surface echo (or TTE) can define most heart structures, the atrial septum ( the site of the PFO) is hard to see.
TransEsophageal Echo (or TEE) uses a special ultrasound probe which is placed in the esophagus after giving sedation. The atrial septum and PFO can be clearly seen by this technique. |
| Transcranial Doppler |
TransCranial Doppler (or TCD) is a new, non-invasive test for diagnosing the presence of a PFO. TCD is more sensitive than TTE or TEE for finding a PFO, but does not show heart anatomy. TCD+TTE may render TEE unnecessary.
When microscopic bubbles are injected by IV into a vein in a normal heart, the lungs reduce their passage to the left side of the heart.
When a PFO is present, TCD detects bubbles which pass through the PFO and travel to the arteries in the brain. TCD, unlike TTE/TEE, is quantitative.
The abnormal flow of blood through the PFO (detected by TCD) is called “shunting”. Shunting is one of the hallmarks of the PFO. |
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| What is known about PFO and Stroke |
PFO occurs in 10-15% of all adults
PFO is diagnosed in 50-70% of patients with stroke of unknown cause.
After a first stroke due to PFO, ½ of patients still have moderate to severe disability after 1 year.
After a first stroke due to PFO, second strokes occur at a rate of 2%-9% each year. (depending on risk)
After several strokes from PFO, repeat strokes occur at a rate of 6%-20% each year.
The risk of repeat stroke due to PFO is increased in patients with leg clots, migraine headache, atrial septal aneurysm (seen by echo), and large PFO shunting (seen by TCD). |
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| Not all PFO are the same |
| Risk and Amount of PFO Flow |
While blood flow from the right atrium to the left atrium is the hallmark of a PFO, it is the AMOUNT of flow (or shunt) that is associated with the risk of recurrent stroke; the greater the flow: the greater the risk.
Bubbles injected by an IV appear in the right atrium and are detected by echo when they appear in the left atrium. A small number of bubbles may pass through the lungs.
Tiny PFO communications are low risk for stroke and do not need treatment. Large PFO are much more likely to result in stroke, migraine, decompression illness in divers, and low oxygen levels in the blood. Mistakenly thinking that all PFO are the same is one of the reasons doctors may disagree on PFO treatment. |
| Atrial Septal Aneurysm and Increased Stroke Risk |
In ½ of patients with high flow PFO, the septum primum (lower divider) is redundant and floppy due to excessive tissue. This floppy divider is called an atrial septal “aneurysm” (ASA). It is not at all like a true arterial aneurysm and cannot burst.
In patients with both ASA + PFO, the chance of repeat stroke is increased four fold (even on blood thinning medications). The presence of an ASA in a PFO stroke patient means that the YEARLY stroke risk is 4%. (Risk > 1.5% / year is considered very high). |
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| Defining PFO Stroke Risk |
The guide post for all medical treatment is called RISK STRATIFICATION. Medical tests and patient conditions help to show how much danger exists for a stroke. Since ½ of PFO strokes are disabling strokes, predicting the chance of stroke before it happens seems important.
Four risk factors are established in medical research which indicate a higher
risk for stroke due to PFO. We use these to decide on PFO treatment.
Brain injury on MRI(1) and migraine headache(2) increase the risk of stroke
several fold in addition to high flow(3) and septal “aneurysm”(4). Other conditions may also increase risk: leg clots, sleep apnea, and diving.
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| What Are My Treatment Options? |
No specific treatment
Aspirin/Plavix to reduce clotting
Coumadin to reduce clotting
Open heart surgery to close the PFO
Trans-catheter closure of the PFO
Randomized trials (the strongest form of scientific proof) have not been done for ANY of these treatment options. |
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| PFO Treatment Options |
| ASPIRIN/ PLAVIX/ COUMADIN |
| RISKS |
-Continued lifelong risk of stroke
ranging from 2-9% each year
-Bleeding due to medication effect
aspirin:1.4% per year coumadin:2.2% per year
-Inconvenience of frequent blood tests (coumadin) |
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| BENEFITS |
-No procedure related problems
-Possible reduction in stroke risk
Reduction of stroke due to PFO by medicines remains unproven |
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| OPEN HEART SURGERY |
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| RISKS |
-Serious complications (5%):
death, stroke, nerve injury, lung injury, infection, transfusion, anesthesia, re-operation, chest scar
-5-7 day hospital stay/ 4-6 week recovery period |
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| BENEFITS |
-Reduction of stroke risk
-Good complete closure rate: 90% at our hospital
-Established procedure |
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| CATHETER CLOSURE OF PFO |
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| RISKS |
-Serious complications (0.2%):
death, stroke, infection, bleeding, blood vessel injury, anesthesia, device movement or dislodgement (1:400), incomplete closure (1-5%) clot forming on device (30/10,000 cases) |
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| BENEFITS |
-Stroke reduction to less than 1%
-No scar; minimal pain
-Out patient procedure
-Return to full activity in 2 days |
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| Available Devices For Catheter Septal Defect Closure |
CardioSEAL Septal Occluder
Amplatzer PFO Septal Occluder
These two devices are available for PFO closure. They are not investigational devices but are regulated by the FDA which requires you to have 2 strokes on coumadin (a strong anti-coagulant) before you can receive this preventative treatment.
The Amplatzer SO device is approved for septal defect closure. It has been used “off-label” for PFO closure and in a recent survey (TCT 2005), 90% of centers reported use of this device for PFO closure. Use of devices or medications “off-label” is common, legal, and accepted in medical practice. Indeed, in many circumstances “off-label” treatments are mandatory.
“Off-label” use occurs because research and experience and patient need move beyond original intended use of a therapy. Patients should understand these issues and all options before considering “off-label” treatments.
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| How do PFO devices work? |
The PFO devices consist of two back-to-back umbrellas (CardioSEAL®) or discs (Amplatzer® PFO) which are connected centrally by a thin pin.
The devices are “spring loaded” to open to their original shape after being folded into a catheter or tube for placement in the body. |
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| How do Septal Defect Devices Work? |
The Amplatzer® SO device is similar to the other 2 devices and is inserted in the same way. It is available in 17 sizes rather than 3.
However, this closure device has a thicker middle section which fills the atrial septal defect space better than the thin pin connectors of the other devices.
Use of this device for a PFO septal defect would be an “off-label” use since it was originally intended for an atrial septal defect. |
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| How Do Closure Devices Work? |
The closure device is delivered to the heart through a small catheter or tube. The ICE (echo) catheter is placed in the same vein.
These catheters are introduced into the body through a major vein in the groin. After the procedure, the catheters are removed and sutures are not needed.
TEE (echo) or more commonly Intra-Cardiac Echo (or ICE) and fluoroscopy ( low level xrays) are used to safely and accurately place the devices in the heart. The ICE catheter is placed in the same vein as the device delivery catheter.
The discs or umbrellas on each side of the atrial septum (divider) hold onto the tissue and “pinch” the PFO closed. The SO device “pinches + fills” the septal defect. Device stability and completeness of closure are confirmed by the ICE images immediately during the procedure. |
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| How Septal Occlunders Heal |
Within 3-6 months, the normal lining cells of the heart grow over the device, completely covering the artificial materials.
The occluder device becomes part of the atrial septum and blood flows normally and clots cannot form or pass through the septum. |
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| How Septal Occlunders Heal |
EXPERIENCE
We have performed over 1400 implants: CardioSEAL(261), Amplatzer PFO (750) and Amplatzer SO (450); over 1000 TCD studies; over 750 ICE procedures.
SAFETY
Our very low procedural and device complication results have been published and can be seen on our RESEARCH page.
EFFICACY
Primary efficacy, the correction of PFO flow, is best quantified by our TCD studies: 95% of patients have complete resolution; 4% have residual shunt which is reduced; 1% have no improvement in amount of shunt. |
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| What Happens After Catheter Closure? |
ACTIVITY:
Return to normal activity in
2 days
MEDICATION:
Aspirin 6 months
Plavix 3 months
TESTING:
TCD 3 months
TTE 3 months
Other testing may be required
RESTRICTIONS:
No dental care for 6 months
No contact sports for 1 month
No heavy lifting for 1 month |
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| How Septal Occlunders Heal |
| Our rigorous Program requirements assure that you are informed and receive the safest and most effective treatment.
Over 25 neurology specialists choose our Program
Different devices and more than one technique for different patient anatomy and physiology assure better results
More than one hospital system to meet insurance needs
A dedicated, specialized team of echo, nursing, catheterization laboratory, and physician members
One of the most experienced centers in this country and abroad with excellent results over many years
Active participation in research and development of new devices, stroke prevention, and new areas of treatment |
