A catheter for insertion into vasculature of a patient to a target area in the vasculature includes a hollow inner shaft, a non-occluding self-expandable scaffold coupled to the distal end of the inner shaft and disposed at the distal end of the inner shaft, and a hollow outer shaft. The outer shaft is slidable over the inner shaft and scaffold such that the scaffold is in a non-expanded state when the outer shaft is around the scaffold. The outer shaft has a state where the distal end of the outer shaft remains near the target area without the inner shaft and the scaffold being within the outer shaft. The inner shaft and the scaffold are removable through the proximal end of the outer shaft while the distal end of the outer shaft remains near the target area.