BALLOON CATHETER TAPERED SHAFT HAVING HIGH STRENGTH AND FLEXIBILITY AND METHOD OF MAKING SAME

• US 20080045928A1
• Filed: 06/15/2007
• Published: 02/21/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Wilson, Bruce M., Durcan, Jonathan P., Simpson, John A.
• Granted Patent: US 8,382,738 B2
• Time in Patent Office: Days
• US Class Current: 604/525
• CPC Class Codes: A61L 29/06 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61M 2025/018 Catheters having a lateral opening for guiding elongated means lateral to the catheter
• CPC Class Codes: A61M 2025/0183 Rapid exchange or monorail catheters
• CPC Class Codes: A61M 2025/1031 Surface processing of balloon members, e.g. coating or deposition; Mounting additional parts onto the balloon member's surface
• CPC Class Codes: A61M 25/00 Catheters; Hollow probes dilators A61M29/00; peritoneal catheters A61M1/285; tracheal tubes A61M16/04; for drainage A61M27/00; for uterus, vagina or rectum A61M31/00 ; for measuring or testing A61B; materials for catheters A61L29/00
• CPC Class Codes: A61M 25/0009 Making of catheters or other medical or surgical tubes
• CPC Class Codes: A61M 25/0021 characterised by the form of the tubing A61M25/0054 takes precedence
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: A61M 25/1006 Balloons formed between concentric tubes
• CPC Class Codes: A61M 25/1029 Production methods of the balloon members, e.g. blow-moulding, extruding, deposition or by wrapping a plurality of layers of balloon material around a mandril
• CPC Class Codes: A61M 25/1034 Joining of shaft and balloon
• CPC Class Codes: A61M 25/1036 Making parts for balloon catheter systems, e.g. shafts or distal ends A61M25/1029 takes precedence
• CPC Class Codes: A61M 25/104 used for angioplasty
• CPC Class Codes: B29C 2049/7831 characterised by pressure values or ranges
• CPC Class Codes: B29C 2049/7879 Stretching, e.g. stretch rod
• CPC Class Codes: B29C 2791/001 Shaping in several steps
• CPC Class Codes: B29C 2949/08 Preforms made of several individual parts, e.g. by welding or gluing parts together
• CPC Class Codes: B29C 48/001 Combinations of extrusion moulding with other shaping operations
• CPC Class Codes: B29C 48/0018 combined with shaping by orienting, stretching or shrinking, e.g. film blowing B29C48/0017 takes precedence
• CPC Class Codes: B29C 48/09 : Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/10 : flexible, e.g. blown foils
• CPC Class Codes: B29C 48/11 : comprising two or more partially or fully enclosed cavities, e.g. honeycomb-shaped
• CPC Class Codes: B29C 48/13 : Articles with a cross-section varying in the longitudinal direction, e.g. corrugated pipes
• CPC Class Codes: B29C 49/00 : Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
• CPC Class Codes: B29C 49/04 : Extrusion blow-moulding
• CPC Class Codes: B29C 49/08 : Biaxial stretching during blow-moulding
• CPC Class Codes: B29C 49/087 : Means for providing controlled or limited stretch ratio
• CPC Class Codes: B29C 49/18 : using several blowing steps B29C49/16 takes precedence
• CPC Class Codes: B29C 49/64 : Heating or cooling preforms, parisons or blown articles
• CPC Class Codes: B29C 55/26 : biaxial
• CPC Class Codes: B29C 65/02 : by heating, with or without pressure
• CPC Class Codes: B29C 65/48 : using adhesives , i.e. using supplementary joining material; solvent bonding
• CPC Class Codes: B29C 66/1122 : Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/24221 : being circular B29C66/51 takes precedence
• CPC Class Codes: B29C 66/53241 : said articles being tubular and said substantially annular single elements being of finite length relative to the infinite length of said tubular articles making T-shaped pieces by joining tubular articles B29C66/52241
• CPC Class Codes: B29C 66/534 : Joining single elements to open ends of tubular or hollow articles or to the ends of bars
• CPC Class Codes: B29C 66/73711 : oriented
• CPC Class Codes: B29C 66/73713 : bi-axially or multi-axially
• CPC Class Codes: B29D 23/001 : Pipes; Pipe joints pleated hoses B29D23/18
• CPC Class Codes: B29K 2105/258 : Tubular
• CPC Class Codes: B29L 2022/022 : Balloons
• CPC Class Codes: B29L 2031/7542 : Catheters

Abstract

A catheter having an elongated shaft with a tubular member which forms at least a portion of the shaft and which is formed of a biaxially oriented thermoplastic polymeric material, and a method of forming the catheter shaft by radially and longitudinally expanding the tubular member to biaxially orient the polymeric material, and, in one embodiment, tapering the tubular member to form a bending stiffness transition. A catheter of the invention has an improved combination of low bending stiffness, high rupture pressure, and high tensile strength, for improved catheter performance.

Claims

1. A balloon catheter, comprising

a) an elongated shaft having a proximal end, a distal end, an inflation lumen extending therein, and a tubular member which has the inflation lumen therein and which is formed of a biaxially oriented nonporous thermoplastic polymer, and which has at least a section with a diameter tapering distally over a length of at least about 2% of the length of the tubular member such that the tapering section has a bending stiffness that decreases distally by about 20% to about 80% therealong;

and

b) a balloon sealingly secured to a distal shaft section, which has an interior in fluid communication with the inflation lumen, and a rupture pressure which is significantly less than the rupture pressure of the shaft tubular member.

2. The catheter of claim 1 wherein the taper length is greater than about 10 cm.

3. The catheter of claim 1 wherein the taper length is about 30 to about 65% of the length of the tubular member.

4. The catheter of claim 1 wherein the tapered section of the biaxially oriented tubular member has a distally tapering wall thickness and outer diameter, and the bending stiffness increases proximally by at least about 65% therealong.

5. The catheter of claim 1 wherein the tapered section of the biaxially oriented tubular member has a distally tapering inner diameter and a distally tapering outer diameter, and a substantially constant wall thickness.

6. The catheter of claim 1 wherein the biaxially oriented tubular member bending stiffness decreases substantially linearly along the tapering section.

7. The catheter of claim 1 wherein the biaxially oriented tubular member of the shaft is a distal outer member which has a distal end sealingly secured to the balloon and a proximal end sealingly secured to a proximal tubular member, and the bending stiffness decreases by a factor of about 2 to 4.5 along the length of the tapering section.

8. The catheter of claim 7 wherein the catheter is an over-the-wire catheter with a guidewire lumen proximal port at a proximal end of the catheter, and the tapered section has a proximal end at the proximal end of the biaxially oriented tubular member of the shaft and the tapered section length is about 1% to about 20% of the total length of the shaft.

9. A balloon catheter, comprising

a) an elongated shaft having a proximal end, a distal end, a guidewire lumen, an inflation lumen extending therein, an inner tubular member with the guidewire lumen therein, and a proximal outer tubular member with a proximal portion of inflation lumen therein, and a distal outer tubular member which has a distal portion of the inflation lumen therein and which is formed of a biaxially oriented nonporous thermoplastic polymer, and which has a distal section, and a tapering proximal section with a length of at least about 1 cm and with a wall thickness tapering distally such that a bending stiffness of the distal outer tubular member increases proximally by at least about 65% along the tapering proximal section;

and

b) a balloon sealingly secured to a distal shaft section, which has a proximal skirt secured to the distal outer tubular member and a distal skirt secured to the inner tubular member such that an interior of the balloon is in fluid communication with the inflation lumen, and a rupture pressure which is significantly less than the rupture pressure of the shaft tubular member.

10. The balloon catheter of claim 9 wherein the distal section of the biaxially oriented distal outer tubular member extends from the tapering proximal section to the distal end of the biaxially oriented distal outer tubular member, and the distal section of the biaxially oriented distal outer tubular member has a constant inner and outer diameter and a constant wall thickness along substantially its entire length.

11. The balloon catheter of claim 9 wherein the bending stiffness of the distal outer tubular member decreases by a factor of about 2 to 4.5 along the length of the tapering proximal section.

12. The balloon catheter of claim 9 wherein the tapering proximal section of the biaxially oriented distal outer tubular member has a constant inner diameter, and a distally tapering outer diameter.

13. The balloon catheter of claim 12 wherein the bending stiffness of the distal outer tubular member increases proximally by about 200 to about 350% along the tapering proximal section.

14. The balloon catheter of claim 9 wherein the length of the tapering proximal section of the distal outer tubular member is at least about 10 cm.

15. The balloon catheter of claim 9 wherein the tapering proximal section of the biaxially oriented distal outer tubular member has a constant outer diameter, and a distally increasing inner diameter.

16. The balloon catheter of claim 9 wherein the biaxially oriented tubular member bending stiffness decreases substantially linearly along the tapering proximal section.

17. The catheter of claim 9 wherein the biaxially oriented distal outer member has an axial orientation that increases distally along the tapering proximal section, and has a circumferential orientation that is substantially uniform along the entire length of the biaxially oriented distal outer member at least within a radial inner surface portion thereof.

18. The catheter of claim 9 wherein the biaxially oriented thermoplastic polymer has a Shore durometer hardness of not greater than about 55 D to about 75 D, such that the tubular member has a Gurley bending stiffness of not greater than about 50 to about 150 mg, a rupture pressure of at least about 20 to about 50 atm, and a tensile break load of at least about 1 to about 5 lbf.

19. The catheter of claim 9 wherein the balloon is a relatively high pressure balloon having a rated burst pressure of about 14 to about 25 atm, and the rupture pressure of the biaxially oriented tubular member is about 20 to about 50 atm.

20. A method of making a balloon catheter having an elongated shaft with a tapered biaxially oriented tubular member and a balloon on a distal shaft section, comprising:

a) melt-extruding a thermoplastic polymeric material having a relatively low Shore durometer hardness, to form a tube having a lumen, and a first inner and outer diameter, and cooling the extruded tube to a temperature less than an elevated temperature of the melt-extrusion;

b) placing the extruded tube within a capture member, and biaxially orienting the polymeric material of the extruded tube and simultaneously tapering at least a section of the extruded tube, by radially expanding the extruded tube with pressurized media in the tube lumen and simultaneously axially expanding the extruded tube with an external load applied on at least one end of the tube as an external heat supply traverses longitudinally from a first to a second end of the extruded tube in the capture member, an overall axial load on the tubing being controllably varied as at least a section is heated; and

c) cooling the expanded tube to room temperature, the cooled, expanded tube being a tapered biaxially oriented nonporous thermoplastic polymer tubular member, and sealingly securing a balloon to a distal end of the tubular member, such that the tubular member forms at least a portion of the catheter shaft and the balloon has an interior in fluid communication with the tubular member lumen.

21. The method of claim 20 wherein varying the overall axial load comprises varying the external load applied to the end of the tube as the external heat supply traverses along the tube.

22. The method of claim 20 wherein varying the overall axial load comprises varying the pressure of the pressurized media in the tube lumen as the external heat supply traverses along the tube.

23. The method of claim 20 wherein the capture member tapers from a smaller to a larger inner diameter along at least a section of the capture member, and the overall axial load is decreased as the heating nozzle traverses along the tapered section of the capture member from the smaller to the larger inner diameter.

24. The method of claim 21 wherein the overall axial load decreases by a relatively large amount such that the tapered section of the tubular member has a tapering outer diameter and wall thickness and a constant inner diameter.

25. The method of claim 21 wherein the overall axial load decreases by a relatively small amount such that the tapered section of the tubular member has a tapering outer and inner diameter and a constant wall thickness.

26. The method of claim 20 wherein the capture member has a uniform inner diameter, and the overall axial load constant as the first section is heated.

27. The method of claim 20 including heat stabilizing the expanded tube after b) by placing the tube on a mandrel with an outer surface having a shape corresponding to the inner surface shape of the tube, and heating the tube to an elevated temperature sufficient to stabilize the polymeric material of the tube.

28. A method of making a balloon catheter having an elongated shaft and a relatively high pressure balloon on a distal shaft section, the distal shaft section having a relatively high rupture pressure tubular member with a relatively low bending stiffness which varies along a length of the tubular member, comprising:

a) forming a portion of the elongated shaft by extruding a thermoplastic polymeric material having a relatively low Shore durometer hardness, to form a tube having a lumen;

b) placing the extruded tube in a capture member having an inner diameter which is uniform along a first section extending from a first end of the capture member and which tapers along a second section from a second end of the capture member to the uniform diameter first section, and biaxially expanding the extruded tube to thereby biaxially orient the polymeric material of the extruded tube and taper the wall thickness of the extruded tube, the biaxial expansion comprising;

i) longitudinally traversing a heating nozzle along the length of the capture member to heat the extruded tube therein;

ii) pressurizing the interior of the extruded tube to radially expand the extruded tube;

iii) applying an external load on at least one end of the extruded tube to axially expand the extruded tube, wherein the external load is substantially constant as the heating nozzle traverses the uniform diameter first section of the capture member and decreases as the heating nozzle traverses along the increasing inner diameter of the second section of the capture member, to form a tapered biaxially oriented tubular member having a first section with a substantially constant outer and inner diameter and wall thickness, and a second section with a substantially constant inner diameter and a tapering outer diameter and wall thickness;

c) cooling the expanded tube to room temperature, the cooled, expanded tube being a biaxially oriented nonporous thermoplastic polymer tubular member with a tapered proximal section, and sealingly securing a proximal skirt section of the balloon to a distal end of the tubular member after the tubular member is removed from the capture member, such that the tubular member forms at least a distal portion of the catheter shaft and the balloon has an interior in fluid communication with the tubular member lumen.

29. The method of claim 28 including heat stabilizing the expanded tube after b) by placing the tube on a mandrel with an outer surface having a shape corresponding to the inner surface shape of the tube, and heating the tube to an elevated temperature sufficient to stabilize the polymeric material of the tube, wherein the tube is allowed to radially and axial shrink during the heat stabilization.

30. The method of claim 29 wherein the expanded tube inner diameter radially shrinks by no more than about 10 percent during the heat stabilization.