Blood vessel prosthesis and delivery apparatus

A method 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 comprising:

• 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 branch conduit along the first guide wire from a first position in which it projects inside the main conduit to a second position in which it projects out from the main conduit, to locate the first branch conduit in the first blood vessel branch, the first branch conduit turning inside out as it moves from the first position to the second position;
• moving the second branch conduit along the second guide wire from a first position in which it projects inside the main conduit to a second position in which it projects out from the main conduit, to locate the second branch conduit in the second blood vessel branch, the second branch conduit turning inside out as it moves from the first position to the second position.