A method is described for delivering a prosthesis to a branch region of a blood vessel, the branch region having first and second blood vessel branches, the prosthesis comprising a main conduit and first and second branch conduits. The method includes inserting a first guide wire in the blood vessel such that it extends through the blood vessel into the first blood vessel branch inserting a second guide wire in the blood vessel such that it extends through the blood vessel into the second blood vessel branch moving the prosthesis to the branch region by moving the first branch conduit along the first guide wire and the second branch conduit along the second guide wire and moving the first/second branch conduit along the first/second guide wire from a first position in which they project inside the main conduit to a second position in which they project out from the main conduit.
