A medical device such as a catheter may have an elongate shaft that includes a hypotube having a helical cutting formed therein. The elongate shaft may define a lumen that extends within the elongate shaft. An electroactive polymer may be disposed over at least a portion of the hypotube. A medical device may include a spiral cut hypotube having a constant pitch and may be configured to reversibly and temporarily alter the pitch of at least a portion of the spiral cut hypotube. In some cases, the medical device may be configured to reversibly and/or temporarily alter a compressive strength of at least a portion of the spiral cut hypotube.