A new medical apparatus for deployment within an anatomical blood vessel and methods of use thereof. The apparatus comprising: a first tubular wall； and a second tubular wall, placed within the first tubular wall； wherein the first and second tubular walls are firmly connected at their edges, therefore restricted to have same overall longitudinal length； and wherein the second tubular wall is configured to be partially constricted towards its inner radial axis, while maintaining its overall longitudinal length.
