we call that a large penumbra that means that there's areas to save salvageable tissue and for these patients we're going to be very aggressive we're going to try to get that blood clot dissolved even though they're beyond the approved window for TPA so we can give TPA a little bit longer than its approved or we can physically go after the clot and the first mechanical device to be approved by the FDA to pull clots out of the brain is this mercy retriever this is from a company in Mountain View called concentric which has subsequently