Abstract: A catheter to be passed over a guidewire, including a screw portion with a cylindrical hollow shaft and a helical thread portion extending outwardly from the hollow shaft. The screw portion is secured coaxially to a tubular portion formed from a substantially rigid material. The tubular portion has, along a portion of its length, at least two slits having a pattern geometry that limits torsional displacement. The catheter also includes a hub having a lumen joined substantially coaxially to the tubular portion.

Abstract: A catheter to be passed over a guidewire, including a screw portion with a cylindrical hollow shaft and a helical thread portion extending outwardly from the hollow shaft. The screw portion is secured coaxially to a tubular portion formed from a substantially rigid material. The tubular portion has, along a portion of its length, at least two slits having a pattern geometry that limits torsional displacement. The catheter also includes a hub having a lumen joined substantially coaxially to the tubular portion.

Abstract: A coaxial guide catheter to be passed through guide catheter having a first lumen, for use with interventional cardiology devices that are insertable into a branch artery that branches off from a main artery. The coaxial guide catheter is extended through the lumen of the guide catheter and beyond the distal end of the guide catheter and inserted into the branch artery. The device assists in resisting axial and shear forces exerted by an interventional cardiology device passed through the second lumen and beyond the flexible distal tip portion that would otherwise tend to dislodge the guide catheter from the branch artery.