Methods and apparatus for catheters, adaptable tips for catheters, including for aspiration catheters, and aspiration catheters with adjustable tips

1. A movable hollow tip for a distal end of an aspiration catheter, the tip comprising

a support ring having a solid annular element and a plurality of proximally-extending projections wherein at least one of the plurality of proximally extending projections includes a hollow circular end portion,

a plurality of struts wherein adjacent struts are coupled to each other at respective nodes and wherein a plurality of nodes are coupled to the support ring and wherein the plurality of struts form a plurality of parallelograms extending circumferentially to form the shape of a cylinder,

a plurality of extensions wherein each of the plurality of extensions is coupled to respective first and second nodes of adjacent nodes at distal portions of respective parallelograms, wherein each of the plurality of extensions includes at least first and second extension struts extending in a plane perpendicular to an axis of the tip when the tip is in a neutral state and

at least one nonplanar radiopaque marker distal of the first and second extension struts, and

a fluid impermeable coating over the plurality of extensions and the plurality of struts forming a cylindrical wall and extending distally beyond distal end portions of the plurality of extensions.

2. The tip of claim 1 wherein the support ring and the cylinder of the plurality of parallelograms have substantially the same outer diameters when the tip is in the neutral state and unconstrained circumferentially.

3. The tip of claim 1 wherein the at least one marker is non-circular.

4. The tip of claim 1 wherein the at least one marker is one of a plurality of markers and wherein each marker extends arcuately a first distance and axially a second distance and wherein the first distance is greater than the second distance.

5. The tip of claim 4 wherein the first distance is greater than twice the second distance.

6. The tip of claim 1 wherein the at least one marker is asymmetric about a plane bisecting the at least one marker and the plane is perpendicular to the tip axis.

7. The tip of claim 1 wherein the at least one marker extends a first distance in a plane perpendicular to the tip axis greater than a second distance in a direction parallel to the tip axis, and wherein the first distance is substantially four times the second distance.

8. The tip of claim 1 wherein the at least one marker includes a width extending circumferentially and wherein adjacent markers are separated by a gap and wherein a ratio of the marker width to the gap is greater than or equal to substantially one and less than or equal to substantially 6.

9. The tip of claim 1 wherein each extension extends arcuately a third distance and adjacent extensions of the plurality of extensions are spaced apart by a gap extending a fourth distance, and wherein a ratio of the third distance to the fourth distance is greater than or equal to one and less than or equal to six.

10. The tip of claim 1 wherein the at least first and second struts in each of the plurality of extensions includes at least one strut extending in a circumferential direction.

11. The tip of claim 1 wherein at least one extension of the plurality of extensions has a first range of motion circumferentially and a second range of motion radially, and wherein the second range is greater than the first range of motion.

12. The tip of claim 1 wherein at least one extension of the plurality of extensions has a first flexibility circumferentially and a second flexibility radially, and wherein the first flexibility is less than the second flexibility.

13. The tip of claim 1 wherein each of the plurality of extensions is pivotable about a respective axis that is substantially on a chord of a cylinder defined by the tip in the neutral state and includes at least one of the extension struts extending arcuately and at least partly on the chord.

14. The tip of claim 1 wherein the plurality of struts forming the shape of a cylinder define a plurality of openings extending at least partly circumferentially and the coating extends into the openings.

15. The tip of claim 1 wherein the tip is formed from nitinol and has a hollow cylindrical shape.

16. A catheter assembly comprising an aspiration catheter having a catheter body having a distal end portion and a movable hollow tip according to claim 1 supported on the distal end portion of the aspiration catheter.

17. The catheter assembly of claim 16 wherein the distal end portion has a first outer diameter and the support ring has a second outer diameter substantially the same as the first outer diameter.

18. The catheter assembly of claim 16 wherein the catheter body defines a lumen having an inside diameter at the distal end portion and wherein an inside diameter of the tip is substantially the same as the inside diameter of the catheter lumen.

19. The catheter assembly of claim 16 further including an annular element supported on the distal end portion, wherein the annular element includes walls forming key openings for receiving portions of respective ones of the projections of the tip.

20. The catheter assembly of claim 19 wherein the annular element is formed of a radiopaque material.