Catheter and method for making same
The present invention relates to a catheter, its proximal portion and the tip thereof as well as to the method for making the same. The distal flap of the catheter main tube comprises a plurality of reliefs arranged on planes transversal to the tube axis; a tapered portion coaxially connected to the distal flap comprising a plurality of notches complementary to said reliefs.
1. A catheter comprising
a main tube ( 2 ) having a proximal end and a distal end,
said distal end having a flexible portion ( 10 ) extending along an axis and
a tapered tip ( 12 ) connected coaxially to said flexible portion ( 10 ),
said flexible portion ( 10 ) comprising a plurality of external reliefs ( 11 ) arranged on planes transverse to said axis,
said tapered tip ( 12 ) comprising a plurality of internal grooves ( 13 ) complementary to said reliefs ( 11 ) and engaging said reliefs to retain the tip on the main tube,
said tip having a larger proximal end and a smaller distal end,
wherein said reliefs have an outside diameter which increases in a proximal direction from the distal end to the proximal end.
2. A catheter according to claim 1 wherein said reliefs ( 11 ) are arranged on planes perpendicular to said axis.
3. A catheter according to claim 1 wherein said reliefs ( 11 ) comprise corrugations of the tube ( 2 ) wall.
4. A catheter according to claim 1 further comprising a radiopaque marker ( 9 ).
5. A catheter according to claim 4 wherein said tapered portion ( 12 ) further comprises a notch complementary to said radiopaque marker ( 9 ).
6. A catheter according to claim 1 wherein said tapered portion ( 12 ) comprises an apex port ( 14 ) for a guide wire to pass therethrough.
7. A catheter according to claim 6 wherein said tapered portion ( 12 ) comprises a distal section ( 120 ) suitable to fair the diameter of the apex port ( 14 ) with the outer diameter of a sheath ( 3 ).
8. A catheter according to claim 7 wherein said distal section ( 120 ) of said tapered portion ( 12 ) substantially has the shape of a truncated cone.
9. A catheter according to claim 1 wherein said tapered portion ( 12 ) comprises a proximal section ( 122 ) suitable to fair the diameter of the distal section ( 120 ) of said tapered portion ( 12 ) with the outer diameter of said main tube ( 2 ).
10. A catheter according to claim 9 wherein said proximal section ( 120 ) of said tapered portion ( 12 ) substantially has the shape of a truncated cone.
11. A catheter according to claim 9 wherein said proximal section ( 120 ) of said tapered portion ( 12 ) comprises a shoulder ( 17 ).
12. Distal section ( 5 ) of catheter ( 1 ) comprising a tip ( 15 ) according to claim 1 and a first marker ( 8 ) placed at a preset distance in the proximal direction from said tip ( 15 ).
13. Distal section ( 5 ) of catheter ( 1 ) according to claim 12 wherein said distance is preset based on the length of a stent loadable on said catheter ( 1 ).
14. Distal section ( 5 ) of catheter ( 1 ) according to claim 12 wherein said main tube ( 2 ) comprises a shoulder ( 7 ) against which said first marker ( 8 ) is in axial abutment.
15. Distal section ( 5 ) of catheter ( 1 ) according to claim 14 wherein said shoulder ( 7 ) comprises an abrupt change of the main tube ( 2 ) outer diameter.
16. Distal section ( 5 ) of catheter ( 1 ) according to claim 14 wherein said shoulder ( 7 ) comprises a buckling of the main tube ( 2 ) wall.
17. Distal section ( 5 ) of catheter ( 1 ) according to claim 14 wherein said shoulder ( 7 ) comprises a distal end of an intermediate tube ( 23 ) coaxially interposed between said main tube ( 2 ) and said sheath ( 3 ).
18. Distal section ( 5 ) of catheter ( 1 ) according to claim 12 wherein said first marker ( 8 ) is shaped such as to define in turn a shoulder.
19. Catheter ( 1 ) comprising a distal section ( 5 ) in accordance with claim 12 .
20. Catheter ( 1 ) comprising a distal section ( 5 ) in accordance with claim 17 wherein said intermediate tube ( 23 ) comprises a reinforcement ( 25 ) made of a material stiffer than the material composing the wall of said intermediate wall ( 23 ).
21. Catheter ( 1 ) in accordance with claim 20 wherein said reinforcement comprises a metal coil ( 25 ).
22. Method for making a catheter in accordance with claim 1 , comprising the steps of:
providing a main tube ( 2 ) of said catheter ( 1 ),
providing a distal flap ( 10 ) of said main tube ( 2 ) defining an axis;
providing on the outer surface of said distal flap ( 10 ) a plurality of external reliefs ( 11 ) on transverse planes to said axis;
overmolding coaxially to said distal flap ( 10 ) a tapered tip ( 12 ) having a distal end and a proximal end,
wherein said reliefs have an outside diameter which increases in a proximal direction from the distal end to the proximal end; and
providing in said tapered portion ( 12 ) a plurality of notches ( 13 ) complementary to said reliefs ( 11 ).
23. Method in accordance with claim 22 , wherein said step of providing said plurality of reliefs ( 11 ) on said distal flap ( 10 ), comprises in turn the steps of:
loading the wall of said distal flap ( 10 ) of said main tube ( 2 ) by axial compression;
induce a phenomenon of local instability suitable to cause on said distal flap ( 10 ) a plurality of bucklings.
24. Method in accordance with claim 22 , further comprising the step of heating said distal flap ( 10 ) of said main tube ( 2 ).
25. Method in accordance with claim 22 , further comprising the step of supporting said distal flap ( 10 ) of said main tube ( 2 ) with a rigid stylet ( 19 b ).
26. Method in accordance with claim 23 , wherein said step of providing said plurality of reliefs ( 11 ) on said distal flap ( 10 ) comprises a step of using a ferrule.
27. Method in accordance with claim 23 , wherein said step of providing said plurality of reliefs ( 11 ) on said distal flap ( 10 ) comprises a step of using a heated ferrule.
28. Method in accordance with claim 23 , wherein said step of providing said plurality of reliefs ( 11 ) on said distal flap ( 10 ) comprises a step of using a countersunk ferrule.
29. Method for making a distal section ( 5 ) of a catheter ( 1 ) in accordance with claim 12 , comprising the steps of:
providing a tip ( 15 ) by
providing a main tube of said catheter,
providing a distal flap of said main tube defining an axis,
providing on the outer surface of said distal flap a plurality of reliefs on transverse planes to said axis,
overmolding coaxially to said distal flap a tapered tip having a distal end and a proximal end,
providing in said tapered portion a plurality of notches complementary to said reliefs, and
providing a first marker ( 8 ) to a predefined distance in the proximal direction from said tip ( 15 ),
wherein said reliefs have an outside diameter which increases in a direction from the distal end to the proximal end.
30. Method in accordance with claim 29 , wherein said distance is predefined based on the length of a stent loadable on said catheter ( 1 ).
31. Method in accordance with claim 29 , comprising the steps of:
providing a shoulder ( 7 ) on said main tube ( 2 );
axially abutting a first marker ( 8 ) against said shoulder ( 7 ).
32. Method in accordance with claim 29 , wherein said step of providing a shoulder ( 7 ) on said main tube ( 2 ) comprises the step of forcing said distal section ( 5 ) of said main tube ( 2 ) inside a first heated ferrule ( 18 ) with a slightly smaller diameter than the outer diameter of said main tube ( 2 ).
33. Method in accordance with claim 29 , wherein said step of providing a shoulder ( 7 ) on said main tube ( 2 ) comprises steps of:
loading by axial compression the wall of said main tube ( 2 ) by axial compression;
inducing a phenomenon of local instability suitable to cause a buckling on said wall.
34. Method in accordance with claim 29 , wherein said step of providing on said main tube ( 2 ) a shoulder ( 7 ) comprises the step of providing the distal end of an intermediate tube ( 23 ) coaxially interposed between said main tube ( 2 ) and said sheath ( 3 ).