Stroke and PFO
What is a stroke?
A stroke happens when part of the brain does not get enough blood.  The brain tissue in the area that is starved of blood then dies and the functions of that part of the brain are permanently damaged.  Symptoms of stroke depend on the area of the brain that is affected.  For more information on the symptoms of stroke, go to  If part of the brain is starved for blood for a very short period and then blood flow is restored, brain function is affected only temporarily and then can recover completely.  This type of event is called a transient ischemic attack (TIA).  There are many causes of stroke and transient ischemic attacks (TIA).  A neurologist typically asseses patients after a stroke or TIA to determine the likely cause.  Knowing the cause is important so that steps can be taken to reduce the risk of another event. Strokes are common and occur in about 700,000 people in the United States each year.
Stroke and Patent Foramen Ovale (PFO)
In about 40% of patients who have had stroke or TIA, no definite cause is found. This situation occurs most frequently in young and middle-aged adults. In this group of patients with history of stroke and no definite cause, a PFO is found much more frequently than is found in people without a history of stroke. Because of this, we understand that PFOs are the cause of strokes and TIAs in many people.

The likely mechanism of stroke in patients with a PFO and no other cause is passage of small clots from the veins through the PFO to the left-side of the heart, and then to the brain. These clots then block the flow of blood to that area of the brain.

Risk of stroke with a PFO

Patients who have had a stroke or TIA and have a PFO have about a 1-3% per year chance of having another stroke. 

Certain factors may make the risk of subsequent strokes even higher.  If the tissue of the PFO is very mobile, it is called an atrial septal aneurysm*.  In patients with atrial septal aneurysm, the risk of recurrent stroke may be as high as 5% per year.

* Atrial septal aneurysm should not be confused with blood vessel or brain aneurysms that are an unrelated problem

Medical Therapy
After a first stroke or TIA, a complete workup is performed.  If a PFO is present and no other cause of stroke or TIA is found, then treatment is usually started with blood thinners.

The blood thinning drugs usually chosen are either aspirin or coumadin. These medicines work to decrease the risks of subsequent stroke by decreasing the tendency to form clots. Both medicines increase the tendency to have bleeding problems - coumadin much more so than aspirin.

For more information on PFO closure

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