Catheters and related devices to form steps between blood vessels or other anatomical structures.

System comprising a catheter and a torqueable sheath, the catheter being insertable (40) in the cover (10) torqueable; and being insertable cover 10 may bend in a mammalian organism, and comprising a body (12) of the collapsible tubular sheath having a proximal end, a distal end and a hollow lumen (20) extending longitudinally therethrough , said resistance body tubular housing sufficient to transfer torque from the proximal end thereof to the distal end thereof so that the distal end of the sheath body will rotate in substantial correlation with the proximal end of the body torsion cover, said system being characterized by: a surface (30) of catheter coupling formed within the lumen of the cover body, being operative said engaging surface of the catheter to engage the catheter when the catheter is inserted through the cover so that i) will prevent the catheter introducer rotate independently of the cover, but ii) at least will rotate the distal end of the catheter together with the cover.