The present invention concerns a catheter-access sheath assembly (20) comprising a catheter (2) and an access sheath (1) characterized in that the catheter comprises at least a groove (23) extending between an outer hole (12) and an inner hole (11) having a greater width than the width of the security guide (3), in that the access sheath (1) comprises an opening (21) extending longitudinally from a distal end of the access sheath (1), in that the access sheath (1) is rotatable around the catheter (2) between an open position in which the opening (21) of the access sheath (1) at least partially coincides with the groove (23) of the catheter and enables the release of the security guide (3), and a closed position in which the access sheath (1) covers the groove (23) of the catheter (2) and enables to maintain the security guide within the groove (23).
