The delivery system may include, for example, an outer catheter having a distal tip and an inner support member, such as an inner catheter, disposed within the outer catheter. The inner support member includes an anchor member adjacent a distal tip of the inner support member and a support portion axially inward of the anchor member. The support portion is configured for supporting an implantable device thereon. A diameter of the anchor member corresponds to a diameter of a portion of a vessel in which the anchor member is to be disposed. The anchor member is configured to be lodged in the portion of the vessel to locate an intended position of the anchor member and to prevent movement of the inner support member relative to the vessel during release of the implantable device.