A guidewire system for insertion into a vascular system of a human or an animal so as to form a guide for guiding a catheter to a predetermined position. The system comprises a support catheter (5 105) bounding a lumen (6 106) for receiving at least a portion of the guidewire (3 53 103). The support catheter (5 105) comprises a guidewire engagement structure (8 108) for engaging the guidewire (3 53 103) inside the lumen (6 106). The engagement structure in engaged condition causes the guidewire (3 53 103) and the support catheter (5 105) to be held mutually positioned at least in longitudinal direction thereof. (Fig. 3)
