An inner catheter (36) for use in an endoluminal delivery assembly (10) includes a stiffening element positioned at a transition between a hypotube (36a), a middle tube (36b) and a distal tube (36c) of the inner catheter (36) having different flexibilities. The stiffening element comprises three stiffening wires (42) embedded within the internal wall of the inner catheter (36) at their proximal ends. The stiffening wires (42) extend inwardly and distally to meet at an apex (60).