Mini-Stroke Precedes Just 1 In 8 Strokes

October 1, 2009.  One out of every eight strokes is preceded by a milder interruption of blood flow to the brain, called a transient ischemic attack (TIA).  Canadian researchers conclude that such an attack is not the crucial warning sign that physicians need.

For the study published in the Sept. 29 issue of Neurology, researchers found that, of the 16,409 people diagnosed with stroke over a four-year period, 2,032 -- or 12.4 percent of them -- had a TIA in the weeks before the stroke.

As a result, the medical experts concluded that a TIA does not have enough predictive power to warrant intensive preventive measures.

A TIA, which some refer to as a mini-stroke, occurs when a clot briefly blocks a brain artery. Symptoms of a TIA are the same as those of a stroke -- sudden onset of weakness or numbness in an arm or leg, loss of vision or double vision, speech difficulty, dizziness, loss of balance -- but they go away, often in a few minutes. Many people ignore the symptoms, but they are clear signs of possible trouble.

Dr. Larry B. Goldstein, director of the Duke Stroke Center. But he disagrees with the Canadian report's  interpretation of the predictive importance of TIAs.  "They predict 10 to 15 percent of strokes," Goldstein said. "This is not a small number, so it is an opportunity to prevent stroke that you don't want to miss when it happens."

Some medical experts noted that better predictive tools are available.  Many prefers carotid ultrasound, an inexpensive way to listen to blood flow in the main artery to the brain.

Stroke is a leading cause of critical illness with over one million new cases diagnosed in the United States annually according to the American Association for Critical Illness Insurance the national trade organization.