Some embodiments relate to a catheter system having a changeable or adjustable working length. The catheter system can comprise a proximal end, a distal end, and a first axial lumen configured to receive a guidewire formed through at least a portion of the catheter body. A first opening can be formed through a portion of the catheter body and be in communication with the first lumen. The sheath can be rotatable, axially movable, or otherwise changeable from at least a first position to a second position, wherein the sheath can substantially cover the first opening in the catheter body in the first position, and can substantially expose the first opening in the catheter body in the second position.