The invention relates to a catheter-access sheath assembly for positioning an access sheath (1) and a security guide (3) next to the sheath for an intervention in a difficult-to-access area within the body, comprising, along the catheter (2), at least one security channel (61)for positioning a guide (3) , wherein the security channel is a channel extending between an outer hole (12) and an inner hole (11), the wall of the catheter extending between both holes of the security channel being arranged to open under the action of a peel strength directed from inside to outside the channel and the access sheath is a collapse resistant flexible tube.
