An element is disclosed that can be fixed in a blood vessel of a living being has a base body to which a first substance and/or a second substance is/are applied at least in parts. In at least one embodiment, the first substance is determined in such a way that it can be detected from outside of the body of the living being by way of a first non-invasive detection method and reacts with at least one first biochemical substance that is released by the living being into the blood vessel during a first pathological condition of the living being, with the result that the quantity of first substance applied to the base body is reduced. The second substance is determined in such a way that it binds at least one second biochemical substance that is released by the living being into the blood vessel during a second pathological condition of the living being and the presence of the bound substance can be detected from outside of the body of the living being by way of a second non-invasive detection method.
