An expandable introducer sheath provided with a steering mechanism is disclosed. The introducer sheath is configured for providing a prosthesis delivery system percutaneous access to a patient's vasculature. The introducer sheath includes a sheath component defining a central lumen and having a longitudinally-extending, radially-expandable portion. The sheath component also includes a steering wire slidably disposed within a wall thereof that longitudinally extends along the radially-expandable portion. When the steering wire is in a slackened configuration, the steering wire permits a width of the radially-expandable portion to increase. When the steering wire is in a taut configuration, the steering wire permits a distal portion of the sheath component to be manipulated or bent in order to align a distal port of the introducer sheath, for instance, with an ostium of a branch vessel.
