Balloon catheter with non-deployable stent having improved stability
An angioplasty catheter comprises a catheter body having a balloon or other radially expandable shell at its distal end. An external structure is carried over the shell and scores a stenosed region in a blood vessel when the balloon is inflated therein. The catheter has an attachment structure disposed between the catheter body and the balloon to accommodate foreshortening and rotation of the external structure as the balloon is expanded. The external structure may be part of a helical cage structure which floats over the balloon. Stabilizing struts are provided between at least some of the helical struts.
1. A catheter comprising:
a catheter body;
a balloon coupled to the catheter body;
a helical scoring structure disposed over the balloon, the helical scoring structure comprising:
a proximal end coupled to the catheter body;
a distal end coupled to the catheter body;
a plurality of helical elements that longitudinally extend from the proximal end to the distal end; and
a plurality of S-shaped stabilizing struts, wherein each S-shaped stabilizing strut is disposed between and coupled to at least two adjacent helical elements,
wherein the helical scoring structure is configured to radially expand in response to inflating the balloon,
wherein at least one of the proximal end and the distal end moves axially as the helical scoring structure shortens to accommodate for radial expansion of the helical scoring structure during expansion of the balloon.
2. The catheter of claim 1 , wherein the helical scoring structure is configured to rotate about a longitudinal axis of the plurality of helical elements as the balloon is expanded.
3. The catheter of claim 1 , wherein the plurality of stabilizing struts are evenly spaced along the length of the helical scoring structure.
4. The catheter of claim 3 , wherein the plurality of helical elements and the plurality of stabilizing struts are comprised of a metal.
5. The catheter of claim 4 , wherein the plurality of helical elements and the plurality of stabilizing struts are comprised of Nitinol.
6. The catheter of claim 1 , wherein the helical scoring structure is unattached to the balloon.
7. The catheter of claim 1 , wherein the helical scoring structure has a length in a range of about 50 mm to about 300 mm.
8. The catheter of claim 7 , wherein the balloon is capable of expanding to a diameter of about 2 mm to about 24 mm.
9. The catheter of claim 1 , wherein each of the plurality of S-shaped stabilizing struts is coupled to the at least two adjacent helical elements at respective points on the at least two adjacent helical elements and the points are radially offset.
10. The catheter of claim 1 , wherein the helical scoring structure comprises a longitudinal axis and each S-shaped stabilizing strut is generally parallel to the longitudinal axis.
11. The catheter of claim 1 , wherein the S-shaped stabilizing struts extend generally longitudinally between the at least two adjacent helical elements.