A ball-tipped mandrel, separate or integrated on a device delivery assembly, can be used to ease delivery and/or retrieval of an ancillary device within a body vessel having tortuous anatomy. A ball-tipped mandrel can be moved through a catheter as a part of a preparation procedure prior to insertion into a body vessel of a patient. A ball-tipped mandrel can be moved through a catheter during or after insertion into a body vessel of a patient in preparation for delivery of an ancillary device. A ball-tipped mandrel can be integrated onto the distal portion of a device to produce dilation during device delivery.
