Scientists in Israel have developed a device which they believe could prevent thousands of strokes a year.
Many strokes are caused by blood clots travelling to the brain
The simple mesh cylinder is implanted into the two main arteries in the neck and is designed to divert blood clots away from the brain.
The device has already been used successfully on one woman, according to a report in New Scientist magazine.
MindGuard, the manufacturers are now planning clinical trials to test the implant further.
Strokes are the second most common cause of death in the western World. Those who survive are often left disabled.
The most common cause of stroke is a blood clot elsewhere in the body breaking off and travelling to the brain, where it blocks one of the small blood vessels. This deprives cells of oxygen and kills off part of the brain.
MindGuard's device, called the "Diverter", is placed in each of the two carotid arteries in the neck.
One of these arteries carries blood to the brain, the other carries blood to the face.
The mesh device does not stop blood from flowing into the brain. However, it does stop clots from entering. These are instead diverted to the face, where they are much less of a problem.
Ofer Yodfat of MindGuard said the device was implanted in an 80-year-old woman considered to be at high risk of stroke three months ago. He told New Scientist magazine that the woman is still healthy and stroke free.
The implantation was performed by Prof Horst Sievert at the Cardio Vascular Center in Frankfurt, Germany.
Speaking in December, he said: "This first human implant is an important advancement towards preventing stroke and improving the quality of life of many patients."
Peter Rothwell, director of the Oxford Stroke Prevention Research Unit at Oxford University, said the "diverter" could work.
"The device makes sense because about 40% of strokes are caused by blood clots from the heart or arch of the aorta," he said.
However, David Williams of the University of Liverpool said studies would be needed to show the mesh is effective.