Disclosed herein are expandable introducer sheaths and methods of making and using the same. The sheaths minimize trauma to a patient's vasculature by allowing for temporary expansion of a portion of the sheath to accommodate passage of a delivery system for a cardiovascular device, then return to a non-expanded state after the passage of the device. The sheath includes an elongated annular member having longitudinally extending channels that facilitate the sheath's temporary expansion. The channels are positioned in such a way that, upon expansion, they enable the movement of protruding contact surfaces toward the inner and outer surfaces of the annular member, reducing friction between the surface and the passing device. Some embodiments of the expandable sheath include an elastic outer layer that pushes the protruding contact surfaces back towards their original positions after the passage of the device.
