The invention relates to an assembly using a vascular filter accommodated in an implanting sleeve from which it can be partially expelled in the case of temporary filtration. It is used by means of a maneuvering rod to which the filter is connected in a separable manner so that the filter is separated therefrom, and then expelled into the sleeve. The filter may have legs in the shape of a corolla and extensions for retaining it in place in the blood vessel, which naturally define a cylinder. Its use is for the treatment of risk of embolism.