Aspiration catheter systems and methods of use

1 . A catheter system, the system comprising:

a catheter comprising a lumen and a distal end having an opening from the lumen, the lumen having an inner diameter at the distal end of at least 0.052″; and

a catheter advancement element comprising:

a tubular portion having an inner diameter that is at least 0.014″ up to 0.024″, an outer diameter, wherein the outer diameter has at least one snug point; and

a tubular, polymer tip portion located distal to the at least one snug point of the tubular portion, wherein the tip portion has a length and tapers along at least a portion of the length of the tip portion,

wherein the catheter system has an assembled configuration characterized by:

a) the catheter advancement element positioned within the lumen of the catheter, wherein the at least one snug point of the tubular portion is substantially aligned with the distal end of the catheter, and

b) wherein the tip portion in the assembled configuration has at least three points spaced along the length of the tip portion, the at least three points comprising:

a distal point of the at least three points located a distance proximal from a distal-most end of the catheter advancement element, the distal point having a first bending force;

an intermediate point of the at least three points located a distance proximal from the distal point, the intermediate point having a second bending force; and

a proximal point of the at least three points located a distance proximal from the intermediate point, the proximal point having a third bending force; and

c) wherein the catheter system has at least two system points along a length of the catheter system, the at least two system points comprising:

a first system point of the at least two system points located proximal to the distal end of the catheter, the first system point having a first system bending force; and

a second system point of the at least two system points located distal to the first system point by a distance that is at least 1 mm distal to the distal end of the catheter, wherein the second system point can be the same or different from the proximal point, the second system point having a second system bending force,

wherein a difference between the second bending force and the first bending force divided by a distance between the distal point and the intermediate point equals a first flexibility slope;

wherein a difference between the third bending force and the second bending force divided by a distance between the intermediate point and the proximal point equals a second flexibility slope;

wherein an average of the first flexibility slope and the second flexibility slope defines an average tip portion flexibility slope;

wherein a difference between the first system bending force and the second system bending force divided by a distance between the first system point and the second system point equals a third flexibility slope; and

wherein a ratio of the third flexibility slope to the average tip portion flexibility slope is less than 25.

2 . The catheter system of claim 1 , wherein the catheter advancement element further comprises a proximal extension coupled to and extending proximally from the tubular portion, the proximal extension of the catheter advancement element being less flexible than the tubular portion, and wherein the proximal extension of the catheter advancement element has at least one stiffness point located within 125 cm from the distal-most end of the catheter advancement element, the at least one stiffness point has a bending force, wherein a ratio of the bending force of the at least one stiffness point to the first bending force of the distal point is at least 100.

3 . The catheter system of claim 1 , wherein the catheter advancement element further comprises a proximal extension coupled to and extending proximally from the tubular portion, the proximal extension of the catheter advancement element being less flexible than the tubular portion, and wherein the proximal extension of the catheter advancement element has at least one stiffness point located within 125 cm from the distal-most end of the catheter advancement element, the at least one stiffness point has a bending force, wherein a ratio of the bending force of the at least one stiffness point to the first bending force of the distal point is at least 200.

4 . The catheter system of claim 1 , wherein the catheter advancement element further comprises a proximal extension coupled to and extending proximally from the tubular portion, the proximal extension of the catheter advancement element being less flexible than the tubular portion, and wherein the proximal extension of the catheter advancement element has at least one stiffness point located within 125 cm from the distal-most end of the catheter advancement element, the at least one stiffness point has a bending force, wherein a ratio of the bending force of the at least one stiffness point to the first bending force of the distal point is greater than at least 300.

5 . The catheter system of claim 1 , wherein the length of the tip portion is at least 1 cm up to 4 cm.

6 . The catheter system of claim 5 , wherein a ratio of the third bending force of the proximal point to the first bending force of the distal point is at least 2.

7 . The catheter system of claim 1 , wherein a ratio of the first system bending force to the first bending force of the distal point is at least 2.

8 . The catheter system of claim 1 , wherein the catheter has a catheter point located a distance of at least 5 mm proximal from the distal end, the catheter point having a catheter bending force.

9 . The catheter system of claim 8 , wherein the first bending force of the distal point is 5%-15% the catheter bending force.

10 . The catheter system of claim 9 , wherein the third bending force of the proximal point is 50%-90% the catheter bending force.

11 . The catheter system of claim 1 , wherein a difference between the first bending force at the distal point to the third bending force at the proximal point is a function of wall thickness.

12 . The catheter system of claim 1 , wherein the tubular portion of the catheter advancement element has a radiopaque marker band embedded within or positioned over a wall of the tubular portion.

13 . The catheter system of claim 12 , wherein the radiopaque marker band remains external to the lumen of the catheter when the system is in the assembled configuration.

14 . The catheter system of claim 12 , wherein the radiopaque marker band is aligned with the distal end of the catheter when the system is in the assembled configuration.

15 . The catheter system of claim 12 , wherein the radiopaque marker band is positioned near the snug point when the system is in the assembled configuration.

16 . The catheter system of claim 12 , wherein the radiopaque marker band has a proximal edge, a distal edge, and a width between the proximal edge and the distal edge, wherein, when in the assembled configuration, the proximal edge of the radiopaque marker band aligns substantially with the distal end of the catheter such that the radiopaque marker band remains external to the lumen of the catheter.

17 . The catheter system of claim 1 , wherein the outer diameter of the tubular portion extends along a length of the tubular portion, the length being at least 5 cm up to 10 cm, wherein the snug point is located along at least a portion of the length.

18 . The catheter system of claim 17 , wherein the outer diameter is substantially uniform along the length.

19 . The catheter system of claim 17 , wherein the outer diameter is substantially non-uniform along the length.

20 . The catheter system of claim 1 , wherein the at least one snug point is located at least 13 mm from the distal-most end of the catheter advancement element.

21 . The catheter system of claim 20 , wherein the distal point is located 5 mm proximal from the distal-most end of the catheter advancement element.

22 . The catheter system of claim 21 , wherein the intermediate point is located 12 mm proximal from the distal-most end of the catheter advancement element.

23 . The catheter system of claim 22 , wherein the proximal point is located 13 mm proximal from the distal-most end of the catheter advancement element.

24 . The catheter system of claim 22 , wherein the first system point is located 19 mm from a distal-most end of the catheter system.

25 . The catheter system of claim 1 , wherein the at least one snug point is located at least 25 mm from the distal-most end of the catheter advancement element.

26 . The catheter system of claim 25 , wherein the distal point is located 5 mm proximal from the distal-most end of the catheter advancement element.

27 . The catheter system of claim 26 , wherein the intermediate point is located 20 mm proximal from the distal-most end of the catheter advancement element.

28 . The catheter system of claim 27 , wherein the proximal point is located 25 mm proximal from the distal-most end of the catheter advancement element.

29 . The catheter system of claim 28 , wherein the first system point is located 33 mm from a distal-most end of the catheter system.

30 . The catheter system of claim 1 , wherein the ratio of the third flexibility slope to the average tip portion flexibility slope is less than 15.

31 . The catheter system of claim 1 , wherein the ratio of the third flexibility slope to the average tip portion flexibility slope is less than 5.