A method of assembling a Catheter, the Catheter comprising: a catheter body having a proximal portion, a distal portion, a proximal end, and a distal end; a guidewire lumen extending from the proximal end to the distal end of the catheter body; and at least one guidewire channel formed from a tube by; inserting a wire into the tube; and skiving the tube wall along the top of the wire; to thereby form a channel having an open width along the tube; the at least one guidewire channel extending from a channel proximal end to a channel distal end, the channel proximal end being attached to the catheter body at the distal portion thereof and extending in a distal direction therefrom; and a main body self-expandable prosthesis loaded on the distal portion of the catheter and the guidewire channel proximal end extending proximally from the expandable prosthesis and the channel distal end extending out of a side opening in the main body self-expandable prosthesis; the method comprising: - placing the expanded main body self-expandable prosthesis onto a first temporary tube, wherein a first stiffening mandrel is positioned within the first temporary tube; - placing a second temporary tube through a side wall opening of the main body self-expandable prosthesis; - compressing the main body self-expandable prosthesis and holding the main body self-expandable prosthesis in a compressed state using a constraining sheath; - routing a distal end of the second temporary tube through a slit in the constraining sheath and inserting a second stiffening mandrel through the second temporary tube; - removing the first and second temporary tubes; - pushing the guidewire lumen over the first stiffening mandrel and pushing the guidewire channel over the second stiffening mandrel; - bonding a distal tip onto the distal end of the catheter and removing the first and second mandrels. a catheter body having a proximal portion, a distal portion, a proximal end, and a distal end; a guidewire lumen extending from the proximal end to the distal end of the catheter body; and at least one guidewire channel formed from a tube by; inserting a wire into the tube; and skiving the tube wall along the top of the wire; to thereby form a channel having an open width along the tube; the at least one guidewire channel extending from a channel proximal end to a channel distal end, the channel proximal end being attached to the catheter body at the distal portion thereof and extending in a distal direction therefrom; and a main body self-expandable prosthesis loaded on the distal portion of the catheter and the guidewire channel proximal end extending proximally from the expandable prosthesis and the channel distal end extending out of a side opening in the main body self-expandable prosthesis; the method comprising: - placing the expanded main body self-expandable prosthesis onto a first temporary tube, wherein a first stiffening mandrel is positioned within the first temporary tube; - placing a second temporary tube through a side wall opening of the main body self-expandable prosthesis; - compressing the main body self-expandable prosthesis and holding the main body self-expandable prosthesis in a compressed state using a constraining sheath; - routing a distal end of the second temporary tube through a slit in the constraining sheath and inserting a second stiffening mandrel through the second temporary tube; - removing the first and second temporary tubes; - pushing the guidewire lumen over the first stiffening mandrel and pushing the guidewire channel over the second stiffening mandrel; - bonding a distal tip onto the distal end of the catheter and removing the first and second mandrels. - placing the expanded main body self-expandable prosthesis onto a first temporary tube, wherein a first stiffening mandrel is positioned within the first temporary tube; - placing a second temporary tube through a side wall opening of the main body self-expandable prosthesis; - compressing the main body self-expandable prosthesis and holding the main body self-expandable prosthesis in a compressed state using a constraining sheath; - routing a distal end of the second temporary tube through a slit in the constraining sheath and inserting a second stiffening mandrel through the second temporary tube; - removing the first and second temporary tubes; - pushing the guidewire lumen over the first stiffening mandrel and pushing the guidewire channel over the second stiffening mandrel; - bonding a distal tip onto the distal end of the catheter and removing the first and second mandrels.