Stroke Facts

What is a stroke?
A stroke occurs when the blood supply to the brain is blocked or severely reduced by a blood clot or by a rupture in a blood vessel. Without the normal supply of nourishing oxygen contained in blood, brain cells quickly begin to die. The resulting damage can cause disabilities or death.

Approximately 795,000 strokes occur every year in the United States among people of every race, age and gender, according to the National Stroke Association. 144,000 Americans die each year from stroke, and the disease is a leading cause of serious, long-term disability.¹

What are the risk factors? Major risk factors of stroke include high blood pressure, heart disease, diabetes and tobacco use. Nearly 40% of people who suffer stroke, however, have no known risk factors.² Their diagnosis is cryptogenic stroke, meaning stroke of an unknown origin or cause.

What are the warning signs?
These major symptoms often occur suddenly:

• Weakness or numbness of the face, arm or leg, especially on one side of the body
• Confusion, difficulty speaking or understanding others
• Change in vision in one or both eyes
• Difficulty walking
• Dizziness, loss of balance or coordination
• Sudden severe headache with no known cause

If you have or are experiencing these symptoms, you should see a doctor.

Is cryptogenic stroke linked to a common heart defect?
Medical researchers have suspected for some time that cryptogenic stroke could be linked to a common heart defect, patent foramen ovale (PFO). Studies have shown that nearly half of people who suffer a cryptogenic stroke also have a PFO.³

What is a patent foramen ovale?
A PFO is a small hole between the upper chambers of the heart. The opening is normal in babies developing in the womb and it usually closes after birth. But this hole remains open in nearly a quarter of all people, though many don't know it because there are no symptoms.⁴

Medical researchers now know a PFO allows blood to bypass the normal filtering system in the lungs. Studies indicate this unfiltered blood can carry small blood clots to the brain - triggering a stroke. But clinical trials involving survivors of cryptogenic stroke who have a PFO are needed to help determine the best treatment for these patients; PFO closure with a device or by taking medication.

Links:
Learn more about the RESPECT Trial
Learn more about stroke and its causes

¹ National Stroke Association
² Sacco, R. et al: Infarcts of Undetermined Cause: The NINCDS Stroke Data
   Bank. Annals of Neurology 25 (4), 1989
³ Lechat, P. et al: Prevalence of Patent Foramen Ovale in Subjects with Stroke.
   The New England Journal of Medicine (318) 1988
⁴ Hagen, P. et al: Incidence and Size of Patent Foramen Ovale During the First
   10 Decades of Life: An Autopsy Study of 965 Normal Hearts. Mayo Clinic
   Proc. 59, 1984