Researchers are finding that the fibers that form blood clots are tougher and more elastic than they suspected. And doctors say this discovery could lead to better treatments for heart attacks and strokes.

The research findings are in tomorrow's edition of the journal Science.

They say the fibers are more stretchy than any other naturally occurring fiber, even spider silk.

Blood clots seal wounds, prevent bleeding and start the body's healing process. But they can also prove dangerous, blocking critical arteries.

Researchers at Wake Forest University say the stretchiness of blood clots also make them difficult to remove.

They are already talking to the makers of an ultrasound device that's used to treat problem blood clots.