Sliding friction between a catheter and a guiding core is reduced by a rotating inner catheter member (12), introduced between the guiding core (13) and an outer catheter member (11). The inner catheter member (12) is rotated in the outer catheter member (11) by a motor (14), which may be controlled by a control unit (2). A lower catheter friction with respect to the guidewire allows the physician improved assessment of the forces resulting from collisions of the outer catheter member (11) and the vascular wall.
