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WO1995029051A1 - Tete et systeme d'extrusion - Google Patents

Tete et systeme d'extrusion Download PDF

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Publication number
WO1995029051A1
WO1995029051A1 PCT/US1995/004105 US9504105W WO9529051A1 WO 1995029051 A1 WO1995029051 A1 WO 1995029051A1 US 9504105 W US9504105 W US 9504105W WO 9529051 A1 WO9529051 A1 WO 9529051A1
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WO
WIPO (PCT)
Prior art keywords
section
resin
flow channel
volume
tube
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1995/004105
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English (en)
Inventor
James C. Wang
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Individual
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Individual
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Publication date
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Publication of WO1995029051A1 publication Critical patent/WO1995029051A1/fr
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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M25/00—Catheters; Hollow probes
    • A61M25/0043—Catheters; Hollow probes characterised by structural features
    • A61M25/0054—Catheters; Hollow probes characterised by structural features with regions for increasing flexibility
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M25/00—Catheters; Hollow probes
    • A61M25/0009—Making of catheters or other medical or surgical tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
    • B29C48/11—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels comprising two or more partially or fully enclosed cavities, e.g. honeycomb-shaped
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/12—Articles with an irregular circumference when viewed in cross-section, e.g. window profiles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
    • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
    • B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/30—Extrusion nozzles or dies
    • B29C48/32—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/30—Extrusion nozzles or dies
    • B29C48/32—Extrusion nozzles or dies with annular openings, e.g. for forming tubular articles
    • B29C48/335—Multiple annular extrusion nozzles in coaxial arrangement, e.g. for making multi-layered tubular articles
    • B29C48/337—Multiple annular extrusion nozzles in coaxial arrangement, e.g. for making multi-layered tubular articles the components merging at a common location
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/475—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using pistons, accumulators or press rams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/753—Medical equipment; Accessories therefor
    • B29L2031/7542—Catheters

Definitions

  • Catheters are used in the field of -medicine in a variety of medical and surgical procedures. For example, catheters are used extensively for delivering diagnostic or therapeutic agents to a selected site within the body. Microcatheters are used in neurointerventional and similar procedures. These catheters are commonly threaded through a vessel or artery and frequently follow a, tortuous path in order to reach the site where the agent is to be applied.
  • a balloon catheter for treating, for example, arterial stenosis has an inflatable balloon at its distal end. This catheter also follows a tortuous path to reach the site of the arterial restriction. The balloon is then inflated via a lumen through the shaft of the catheter, applying pressure to expand the stenosis against the artery wall.
  • the catheter must be rigid enough to allow the distal end of the catheter to be manipulated by the physician or surgeon.
  • the catheter must be quite flexible to permit it to follow the tortuous path to the desired site of application.
  • various designs of catheters are known and used.
  • One such catheter utilizes a flexible catheter with an inflatable balloon at its distal end which, when partially inflated, will be carried by the blood flow to the desired location.
  • Such catheters cannot be used if the site where the agent is to be applied can be accessed only through a vessel that has a low blood flow rate.
  • guide wires are used which can be advanced to the site, and with the guide wire in place, the catheter can then be telescoped over the wire and advanced to the application site.
  • Catheters that use the guide wire technique still must be sufficiently flexible to track the wire and sufficiently rigid so that , the catheter can be advanced without buckling at the proximal end.
  • differential stiffness catheters have been developed which have different degrees of flexibility throughout their length. These catheters have a long and stiff proximal section coupled to a short and soft or flexible distal section that will track the guidewire. With these differential stiffness catheters, the physician or surgeon can push and maneuver the stiff proximal end to effectively advance the soft distal end;
  • Engelson U.S. Patent No. 4,739,768 discloses a catheter which has a relatively stiff proximal segment and a relatively flexible distal segment, the segments being formed by forming the proximal segment of inner and outer coaxial tubes, one of which is relatively stiff, and the other of which is relatively flexible. The distal segment is then merely an extension of the relatively flexible tube.
  • differential stiffness catheter is usually made by hand by joining two or more pieces of tubing together, they are labor intensive and therefore expensive to manufacture. Moreover, these catheters tend to buckle and to kink at the joints where there occurs an abrupt change in stiffness. Buckling and kinking are very undesirable characteristics for catheters. Also, there is a tendency for the joints to separate leaving the tip of the catheter inside the body and requiring surgery to retrieve it. Attempts have been made to reduce the buckling and kinking problems and prevent joint separation , by making the catheter with a relatively soft layer throughout the entire length of the catheter, but this construction results in reduced stiffness at the proximal end.
  • interrupted layers co-extrusion process results in only a moderate difference in stiffness between the proximal and distal sections - less than is considered desirable for catheters.
  • these co- extrusion processes are not as economically feasible as first thought. Further study has shown that these deficiencies cannot be corrected by simple means, such as process variable changes, but rather require fundamental changes in the process itself.
  • medical catheters must have the proximal end attached to a variety of different connectors which facilitate attachment of one or more medical device or devices necessary to carry out the particular medical procedure using the catheter.
  • kinking can easily occur and restrict the flow of the fluid being introduced into the catheter tube.
  • prior art catheters commonly use a short length of a flexible rubber tube that extends from the connector and into which the proximal end of the catheter is inserted and affixed. Although use of this rubber tube reduces kinking of the catheter tube, there is still considerable strain applied to the catheter tube at the point where it exits the rubber tube connector. This kinking problem also exists in tubing used in nonmedical applications.
  • the invention relates to the manufacture of a tubing having different properties, for example differential stiffness, in different sections along its length.
  • Such tubing is useful in many medical applications, such as catheters.
  • a catheter extruded utilizing the extrusion head and system of the invention has a stiff proximal section for "pushability", a flexible, soft distal section for tracking the guidewire and a unique transition section of controlled length, e.g., significantly shorter than is possible with prior art extrusion heads, in which the stiff material of the proximal section and the flexible material that forms the distal section are sequentially co-extruded, e.g., "wedged into” one another to produce an extremely secure, practically non-breakable joint between the two materials.
  • the merging of the two materials is very smooth and gradual to eliminate kinking that usually occurs at abrupt joint between two materials of different stiffness.
  • the gradual transition also facilitates tracking of the guidewire and is short enough to be useful in catheter applications, including so-called microcatheters.
  • the average length of the transition section in such medical catheter tubing is about 0.25 - 20 inches, preferably about 0.5 - 10 inches.
  • a co- extrusion head and a system including such a head are provided.
  • the co-extrusion head is designed to minimize , volumes for all the flow channels, within limits discussed further below, and has no moving parts which is essential to precisely control the diameter of the tubing and to assure consistently high quality of the final product.
  • the design of the co-extrusion head also provides for virtually mutual exclusivity of resins, i.e., it is possible to produce a tubing that has virtually 100% of the stiff resin in the proximal section a ⁇ id virtually 100% of the soft resin in the distal section.
  • the system of the invention provides for the production of tubing using several thermoplastic resins of varied stiffness which can be automatically fed into the co- extrusion head in a precisely synchronized fashion to produce a tubing having different resins or resin combinations in different sections of the tubing, always with gradual transitions from one to the other in short transition sections.
  • the co-extrusion head and system are designed for the fabrication of an elongated tube having an annular wall with an outer surface and an inner surface that defines a central passageway.
  • the elongated tube includes a first section formed of a first resin, a second section formed of a second resin, and an intermediate section joining the first section and the second section.
  • the intermediate section is a transition section in which the tube wall gradually changes from the first resin of the first section to the second resin of the second section to form a continuous unbroken tube without abrupt joints.
  • the co-extrusion head includes a body defining a first flow channel, a second flow channel, and a joint flow channel, each having an upstream end and a downstream, end. The downstream ends of the first and second channels open into the upstream end of the joint flow channel.
  • the body further defines a first inlet for the introduction of a first resinous stream of the first resin into the , upstream end of the first channel, a second inlet for the introduction of a second resinous stream of the second resin into the upstream end of the second channel, and an exit for the discharge of the first and second resinous streams from the co-extrusion head.
  • the co-extrusion head further includes a die closely fitting within the exit, and a tip.
  • the die has a passageway therethrough of a geometry selected to produce the outer surface of the tube wall. A portion of the tip is disposed within the die passageway to be coaxial therewith, and the geometry of the outer surface of the tip is selected to produce the inner surface of the tube wall.
  • the co-extrusion head includes no moving parts, and the contact volume within the joint flow channel is selected to determine the length of the tube transition section.
  • the co-extrusion system includes the above-described co-extrusion head and modulating means for controlling the flow of the second resinous stream into the second inlet.
  • Figs. 1A, IB, 1C, ID, IE and IF are longitudinal cross- sectional views of a portion of differential stiffness catheters of the type to which the invention , relates;
  • Fig. 2 is a schematic diagram of a system for producing a differential stiffness catheter using the co-extrusion technique of the invention
  • Figs. 3A and 3B are views, partly in section, of a two-stage flow modulator used in the system of the invention, Fig. 3A being a front elevational view and Fig. 3B being an end elevational view;
  • Fig. 4 is a side elevational view partly in cross- section illustrating a three-layer co-extrusion head utilizing the principles of the invention. •
  • Fig. 5 is an end view of the co-extrusion head of Fig. 4;
  • Fig. 6 is side elevational view partly in cross-section similar to Fig. 4 but showing a two-layer co-extrusion head
  • Fig. 7 is a series of diagrams showing the steps of a process performed using the principles of the invention.
  • Figs. 8A, 8B and 8C each contain various views of a section of a catheter to illustrate the differences between a slanted end and an even end, and the configuration normally found in an even end;
  • Figs. 9A and 9B each contain various views of a catheter end to illustrate the differences between a layer construction and an elements construction;
  • Fig. 10 is a longitudinal sectional view of another type of tubing that can be produced using the principles of the invention.
  • Fig. 11 is a longitudinal sectional view of still another type of tubing that can be produced using the, principles of the invention.
  • Figs. 12A - 12F show a multi-lumen catheter tubing produced using the principles of the invention
  • Fig. 13 is an angiographic catheter produced using the principles of the invention.
  • Fig. 14 is a strain relief joint including tubing produced using the principles of the invention.
  • Fig. 15 is a soft tip guiding catheter produced using the principles of the invention.
  • Fig. 16 is a catheter guidewire coated with tubing produced using the principles of the invention.
  • Fig. 17 is a metal braid reinforced tubing produced using the principles of the invention.
  • Fig. 18 is a wire wound tubing produced using the principles of the invention.
  • Figs. 1A, IB, 1C, ID, IE and IF there are illustrated differential stiffness catheters of the type to which the invention relates.
  • Such catheter tubing is typically of an outside diameter of about 0.25 - 0.02 inch.
  • the tubing and process described herein are most valuable for catheters no larger than 0.08 inch outside diameter.
  • the diameter has been greatly enlarged and the length compressed so as to clearly show the different layers between the catheter walls.
  • the catheters shown in Figs. 1A, IB, 1C, ID, IE and IF each have an inner wall 10 and outer wall 12 that define an annular tube with a longitudinally or axially extending passageway 14 through which a guidewire (not shown) can be passed and through which fluid flows.
  • the catheter has a distal section 16 which is commonly the soft or flexible portion of the tube and a proximal section 18 which is the stiff portion of the tube.
  • the "transition section” 19 is the length of the catheter in which the tube changes from a stiff tube to a soft tube.
  • the term “transition section” is defined further below.
  • a key feature of the invention is the gradual change and the controlled, shorter length of the transition section between the soft, flexible portion and the stiff portion of the tube.
  • Another key feature of some aspects of the invention is the "wedged-in” construction in the transition section 19 of the catheter where a layer of one , material forms a wedge-shaped profile extending into another material. This construction is naturally formed provided that the "skewing volume”, (defined hereinafter) is not overly short, and the viscosity of the "wedging" material or resin is not overly high when compared with the "wedged” resin.
  • the speed of flow of the resin is usually the greatest near the center of any flow channel of the co-extrusion head and slowest near the walls of the flow channel. Therefore, any new and different material introduced into one flow channel tends to flow out first near the center of the channel and last near the walls, thus forming the "wedged-in" structure.
  • Another way of forming a "wedged-in” construction is to introduce an interior layer at a gradually increasing rate.
  • one material or resin is always gradually combined with another material in the transition section 19, in some aspects of the invention forming a "wedge" structure.
  • the "wedge” can be in the form of a gradually thinning layer, as shown in Fig. 1A, or in other gradually changing shapes, such as multiple spear points.
  • this wedge construction forms an extremely secure, virtually unbreakable joinder between two resins because of the large surface contact area created between the two resins which effectively restricts relative movement between them.
  • Fig. 1A shows a catheter in which the proximal section 18 is of a single layer of material that makes the section 18 stiff.
  • the distal section 16 is also of a single layer of soft material that makes the distal section 16 soft and flexible.
  • the stiff material of the proximal section 18 is wedged into the soft material of the distal section 16, thus providing an enclosed, secure joinder of the stiff and soft materials and avoiding an abrupt change in material that can cause kinking.
  • Fig. IB shows a catheter in which the stiff material of the proximal section 18 is an inside layer 15 with the soft material of the distal section 16 forming an outside layer 14 along the proximal section 18 as well as the transition section 19. As in the embodiment of Fig. 1A, the stiff material is wedged into the soft material in the transition section 19.
  • Fig. 1C the construction of the catheter is similar to that of the embodiment of Fig. IB except the stiff material also extends into the distal section 16 to form a thin inside layer 13 with the soft material forming the outside layer 14 as in the embodiment of Fig. IB.
  • Fig. ID shows a catheter construction in which the stiff material of the proximal section 18 forms an interior layer 17, and the stiff material extends into the transition section 19 and is wedged into the soft material of the transition section 19.
  • the outside layer 14 is uninterrupted and , extends the entire length of the tubing from the proximal section 18 through the transition section 19 and the distal section 16.
  • the inside layer 13 is of a different material from the material of either the outside layer 14 or the interior layer 17, layer 14 being of a material that is softer than the stiff material but suitable for movement of a guide-wire.
  • Fig. IE shows a catheter construction in which a plurality of materials of different stiffness provide a differential stiffness catheter.
  • the stiffest material of the proximal section 18 forms an interior layer 15, and the stiffest material extends into the transition section 19 and is wedged into the less stiff material in portion 19c of transition section 19. This less stiff material, in turn, is wedged into a softer material in portion 19b of transition section 19, which, in turn, is wedged into the softest material in portion 19a of transition section 19.
  • four materials of different stiffness provide the differential stiffness along the length of the catheter.
  • three or more than four materials may also provide a similar construction.
  • both the outside layer 11 and the inside layer 15 are uninterrupted and extend the entire length of the tubing from the proximal section 18 through the transition section 19 and the distal section 16.
  • the four different materials are successively wedged into one another in such a way that portions 19a, 19b and 19c of transition section 19 overlap and three materials are present in each area of , overlapping portions.
  • portions 19a, 19b and 19c may be immediately adjacent to or separated from one another within transition section 19 to provide differential stiffness for the catheter.
  • Fig. IF illustrates a non-wedged construction in which the stiff material and the soft material both extend the full length of the catheter, the differential stiffness resulting from a change in relative thickness of the two materials which takes place in the transition section.
  • the stiff material forms an inside layer 15 which is significantly thicker in the proximal section 18 than in the distal section 16, gradually decreasing in thickness in transition section 19.
  • the soft material forms an outside layer 11 which is significantly thinner in the proximal section 18 than in the distal section 16, gradually increasing in thickness in the transition section 19.
  • inner layer 15 provides a continuous smooth surface for passage of a guidewire
  • outer layer 11 provides a low-friction layer for passage of the catheter through bodily passages.
  • transition section 19 in such a catheter is about 0.25 to 20 inches long.
  • either inner layer 15 or outer layer 11 may not extend the entire length of the catheter; that is, inner layer 15 may terminate anywhere along the length of proximal section 18 or outer layer 11 may terminate anywhere along the length of distal section 16.
  • either inner layer 15 or outer layer 11 or both extend the entire length of the catheter.
  • three or more materials may extend along the length of the catheter in a non-wedged construction.
  • a third material may provide an interior layer of intermediate stiffness between the stiffer layer and the softer layer. This interior layer provides a relatively thick lengthwise layer segment in transition section 19 between the thicker stiff layer of proximal section 18 and the thicker soft layer of distal section 16, gradually decreasing in thickness in the proximal and distal sections.
  • transition section refers to the portion of the catheter in which the properties of the tubing change from those principally provided by one material, i.e., the primary material of the distal section (distal primary material) to those principally provided by another material, i.e., the primary material of the proximal section (proximal primary material) .
  • the volume percent of the proximal primary material changes from a maximum in the proximal section to a minimum in the distal section, while the reverse is true for the distal primary material.
  • the transition section therefore, may be defined relative to this maximum volume % of the proximal primary material (Vmax) .
  • the term "transition section” is defined as the portion of the tubing between two points along the length of the tubing.
  • the proximal primary material at the proximal end point of the transition section is at least about 95% of the Vmax, while the proximal primary material at the distal end point of the transition section is no more than about 5% of the Vmax.
  • the Vmax is 100%
  • the transition section is the portion between about 95% (95% of 100%) and about 5% (5% of 100%) by volume of the proximal primary material.
  • the outside layer of the distal primary material carried throughout the length of the tubing does not affect the definition of the transition layer, i.e., if the Vmax (of the proximal primary material) is 80%, the transition section is the portion between about 76% (95% of 80%) and about 4% (5% of 80%) by volume of the proximal primary material.
  • the proximal primary material is carried into the distal section as an inside layer throughout the catheter tube. Therefore, for the purpose of determining the transition section boundaries, this layer may be treated as a separate material not part of the Vmax.
  • the Vmax is about 90%
  • the transition section is the portion between about 85.5% (95% of 90%) and about 4.5% (5% of 90%) by volume of the proximal primary material.
  • the primary difficulty encountered in co-extrusion of differential stiffness tubing as taught by the prior art is the length of the transition section 19.
  • the prior art co-extrusion heads and systems that result in these undesirable long transition sections.
  • a co-extrusion head indicated, generally, by the reference numeral 20 into which extruders 22, 24 and 26 feed the different resins, such as a soft resin and a stiff resin, that will be used to form the finished tubing.
  • extruder 22 provides a resinous stream for a resin "A” which, for example, will ultimately form the outside layer 14 of the catheter of Fig. ID, while extruder 26 provides a stream of resin "B" that will form the interior layer 17 of the finished catheter.
  • extruder 24 provides a resinous stream for resin "C" which is the material that will form the inside layer 13 of the finished catheter.
  • a modulating device indicated generally by the reference numeral 28, regulates the flow of the resins from each of the extruders 22 and 26 into the co-extrusion head 20, while another modulator 27 may be used to bleed resin "A” from the head 20 to relieve residual pressure.
  • the modulators 28 are actuated periodically and in synchronized fashion to abruptly stop or change the resin flow to the head 20.
  • the tubing is cooled by passage through a water tank
  • a co-extrusion head is an assembly of many precision machined parts that provide a plurality of flow channels, each of which is connected to one of the extruders.
  • Fig. 4 illustrates the design of a co-extrusion head 20 for producing a tubing of three different materials, such as that shown in Fig. ID.
  • Fig. 6 illustrates a head design for producing a tubing of two different materials, such as the tubing illustrated in Figs. 1A, IB and lC.
  • the co-extrusion head 20 has a main body 30, usually of a cylindrical shape, in which is formed an inlet 32 for resin "A", an inlet 34 for resin "B” and an inlet 36 for resin "C” .
  • each of the inlets is connected to the respective one of the extruders 22, 24 and 26, and through a flow channel formed in the main body 30, to a die 40 which, together with the tip 42, forms the exit from the head 20 for the flow of resins to create the desired configuration of the finished product.
  • the co-extrusion head 20 has a flow channel 38 connected to inlet 32 for resin "A”, a flow channel 44 that is connected to inlet 34 for resin "B” and a flow channel 46 that is connected to inlet 36 for resin "C” .
  • a removable cap 48 on main body 30 provides access to the head to change the die 40 and tip 42.
  • the design of the head 20 can be such so as to include in the same co-extrusion head 20 both large and small dies 40 and tips 42.
  • a side stream means any resinous stream in the co-extrusion head 20 of the type of Fig. 4 that is either on the outside or on the inside at point 51 where the resinous streams meet prior to exiting the head 20 at point 52.
  • interior stream is any resinous stream in the co-extrusion head 20 that is between two side streams at point 51.
  • Contact volume of any resin, such as resin "C” is the volume in the flow channel portions of the co-extrusion head 20 where resin “C” is flowing jointly with at least one other resin, such as resin "B”, and where resin "C” is in intimate contact with solid non-moving surfaces of the head 20 in the section where there is such joint flow.
  • contact surface means the solid, non-moving surface of head 20
  • the "residual flow volume of a resin” is the volume of a flow channel section between the, discharge from the modulator 28 and the point where the resin joins another resinous flow for the first time.
  • the "skewing volume” of a resin is the volume in a flow channel between the point where the resin stream "C” joins another flow stream for the first time (the start of the contact volume) and the point where the resin exits from the co-extrusion head 20.
  • the "skewing volume” of all three resins is the volume in a flow channel between point 51 and the resin exit point 52.
  • the contact volume and the skewing volume are probably the most influential factors in forming the length of the transition section.
  • the undesirable lengthy transition section occurs in prior art co-extrusion heads because the solid contact surface drastically slows down the resin flowing by it to cause a "drag-out" effect that overly elongates the resin interface.
  • zero contact volume should be designed into the co-extrusion head 20 since zero contact volume design completely or substantially eliminates the drag-out
  • Fig. 4 illustrates a flow channel arrangement in a co-extrusion head design that we have termed a "die-length contact volume" head design.
  • the contact volume is no greater than the volume covered by , the length of the die 40 multiplied by a factor of 10, and is no less than the volume covered by the die length.
  • the contact volume is equal to the volume covered by the die length.
  • This "die length contact volume" head design is especially useful in interrupted side streams in co-extrusion rather than where the center streams are interrupted, and in some designs, the use of a die is deemed necessary to control the overall tube concentricity and assure its uniformity. As a practical matter, in many cases the contact volume should not exceed the volume contained in the desired transition section length multiplied by a factor of 10. For producing some catheters of a small diameter, the contact volume can be as small as 0.5 ml. Thus, by the die-length contact volume design of the co-extrusion head 20 as shown in Fig. 4 for resin "A" , one of the most influential causes of lengthy transition sections is practically eliminated.
  • the design of the head 20 shown in Fig. 4 uses a die-length contact volume for resin "A", and by changing the thickness of the die 40, the contact volume can be varied.
  • the length of the transition section also can be changed by a simple change of tooling in the tip 42 and die 40 of the head 20. By changing this tooling, both the skewing volume for resins "A” and "B” and the contact volume for resin "A” can be modified.
  • the length of the transition section 19 in a differential stiffness catheter there are other factors that influence the , length of the transition section 19 in a differential stiffness catheter.
  • One factor that influences the length of the transition section is the final cross-sectional area of the tubing to be formed. Tension and internal air pressure are applied, as is known in the art, to the hot, as-extruded tubing exiting the extrusion head, resulting in elongation and shaping of the tubing to preselected inside and outside diameters.
  • the length of the transition section is inversely proportional to the final cross-sectional area of the wall of the tubing. In other words, thin tubing with very small diameters tend to have very long transition sections.
  • the length of the transition section can also be changed by changing the viscosity of the resins. For example, when the leading edge of the stiff layer is used to wedge into the layer of softer material as illustrated in Figs. 1A, IB, 1C and ID, raising the viscosity of the stiff layer or lowering the viscosity of the softer side layers will shorten the length of the transition section.
  • the head design includes adjustment screws 54 on the rear of the head 20. By adjusting the screws 54, the length of the annular stiff layer, and thus the length of the transition section 19, can be varied along only a portion of the annular layer to produce a slanted end, as illustrated in Fig. 8A. Fig.
  • FIG. 8B shows the stiff layer of uniform length around the entire circumference to produce , an "even" wedge.
  • the tubings are shown schematically; in particular, the downstream, thinner ends of the wedges of the stiff layers are shown as sharp edged and smooth.
  • the downstream edge of the wedged-in layer ends in a plurality of longitudinally extending "spear points" of one material extending into the other in the wall of the transition section, as shown in Fig. 8C.
  • points of the stiffer material extend into the softer material.
  • the downstream ends of the points are circumferentially spaced apart in the wall of the transition section, and the points gradually increase in size in the upstream direction until they join to form the annular layer shown in Figs. 8A - 8C.
  • this lag distance can be as short as a fraction of an inch or as long as many feet.
  • the lag distance increases with the increase of skewing volume and it is inversely proportional to the final cross-sectional area of the tubing.
  • An important design feature of the invention is that the co-extrusion head 20 of the invention has no moving parts, thus assuring that the diameter of the tubing will be consistently accurate which is especially important for medical tubing such as catheters. Also important in maintaining consistent diameters of the tubing is the close match of melt strengths of the resins used.
  • the modulator 28 is also important in order to regulate and control the actual length of the transition section as well as the profile for any particular tubing.
  • the modulator 28 functions to regulate the flow rate of the resins in a rapid and precise fashion.
  • a typical modulator 28 is illustrated in Figs. 3A and 3B, which show a two-stage type modulator in which the flow can be regulated so as to flow through to the head 20 or interrupted to direct the resin flow to a recycling container (not shown) .
  • the modulator 28 must be fast acting so as to operate to change the flow within no more , than two seconds and preferably in less than 0.5 seconds.
  • the modulator 28 thus has an inlet 56 leading to a chamber 57 into which extends a valve member 58 operated by actuator 60.
  • the resin flowing into the chamber 57 is directed to the outlet 62 which is connected to the head 20 or the resin is directed into a bypass outlet 64.
  • a variety of different designs of the modulating device 28 can be utilized as long as they have extremely fast responses and can produce rather precise flow controls. Since a typical cycle for making one length of tubing for a single catheter is only about 0.5 to 10 seconds, rapid response is extremely necessary.
  • the modulator 28 can be replaced by a plunger type modulating device, actuated by a servo valve with a programmer (not shown) .
  • the programmer may be of any suitable design such as that marketed by "Moog" Electronics and Systems Division which produces and markets a line of parison programming systems.
  • co-extrusion head 20 is properly designed and operated, rather simple on-off types of modulating devices may be sufficient, depending upon the type of tubing being produced. Also, devices with mechanical gradual flow reduction or gradual flow-increase functions can also be used depending upon the tubing requirements.
  • modulators may be programmed to deliver tubing having a consistent diameter throughout the production cycle, small variations do occur due to slight mismatches of the modulators.
  • a tubing can be produced, with the most consistent diameter, e.g., for use as a catheter (before tapering) by keeping the skewing volume greater than the resin volume contained in distal section 16 of the catheter, and preferably greater than the resin volume of the distal section multiplied by a factor of 5.
  • Fig. 7 there is illustrated the operating steps of a complete cycle for producing the differential stiffness catheter of Fig. ID.
  • This figure shows schematically the die 40 and tip 42 of the head 20 and illustrates the flow of the resins through the die 40 and tip 42.
  • the flow of resin "B” is stopped while the flow of resins "A” and “C” are on.
  • the flow of resin "B” is then commenced while the rate of flow of resin "A” is reduced and the flow of resin "C” continues.
  • the transition section 19 is formed.
  • the head and systems designs of the invention are also useful where it is desired to obtain a specified diameter and wall thickness and to combine interrupted resin streams technology with tapering• and lumen air regulating techniques. When so doing, the timing of all these devices should be synchronized to avoid drift.
  • FIG. 12A A typical multi-lumen tubing for such a catheter is shown in Figs. 12A - 12F.
  • tubing 100 includes stiffer proximal section 101, transition section 102, and softer distal section 103.
  • Fig. 12B illustrates a cross section of softer distal section 103 taken along line B-B of Fig. 12A.
  • distal section 103 includes lumens 104 formed within softer material 105.
  • transition section 102 taken along line C-C, D-D, and E-E, respectively, of Fig. 12A.
  • the portion of transition section 102 near distal section 103 includes lumens 104 formed within softer material 105, with inserts of stiffer material 106 on either side of lumens 104.
  • Fig. 12D from near the center of transition section 102, is similar to Fig. 12C, but with larger insertions of stiffer material 106.
  • the portion of transition section 102 near proximal section 101 is made up largely of stiffer material 106, with thin layers of softer material 105 adjacent lumens 104 and the outer surface of transition section 103.
  • Fig. 12C illustrate cross sections of transition section 102 taken along line C-C, D-D, and E-E, respectively, of Fig. 12A.
  • the portion of transition section 102 near distal section 103 includes lumens 104 formed within softer material 105, with inserts of stiffer material 106 on either side of lumens
  • proximal section 101 includes only stiffer material 106, with lumens 104 formed therewithin.
  • stiffer sections each of which may form one or two proximal sections 101
  • softer sections each of which may form one or two distal sections 103
  • a small remnant of stiffer material remains at the core of the softer and transition sections between stiffer sections.
  • Such a remnant is shown in Figures 12B, 12C, and 12D as remnant 107 of stiffer material 106.
  • the multi-lumen catheter may include three or more lumens, and the lumens may have any of a variety of shapes and may be of the same or different shapes and sizes.
  • Such multi-lumen tubing is useful for applications in which known multi-lumen tubing has been found useful, for example, in balloon catheters or electrophysiology (EP) catheters.
  • EP electrophysiology
  • a particular advantage is provided by the variable stiffness tubing in an EP catheter. When the distal tip of the EP catheter is deflected for maneuvering of the catheter through tortuous anatomies, the short transition section and soft distal section permit faster recovery of the straight-line axial configuration than has been achieved in prior art EP catheters.
  • SUBSTTTUTE SHEET (RULE 26) invention not only can be used for making the full length of the catheter, they can also be used to make only a part of the catheter.
  • the invention can be used to make a single lumen tubing inside the balloon, or produce a catheter with the distal section combined with a proximal section formed of either a braided construction or a metal tubing such as Nitenol tubing.
  • Another type of catheter construction to which the principles of the, invention can be applied is to produce a catheter with a low friction layer on the inside surface for good guidewire movement.
  • the catheter distal section may be shaped, e.g., by heating to form a bent configuration in its relaxed state.
  • a J-tip or hook-shaped profile may be formed at the distal tip of the catheter.
  • the wall of this bent or other catheter may be perforated by known means, e.g., at the proximal section to provide for inflation of a balloon via the central passageway or at the transition or distal section to provide for dispensing of fluid medication or a fluoroscopic dye.
  • An example of such a catheter is shown in Fig. 13, showing angiographic catheter 110 having proximal section 111, transition section 112, and distal section 113.
  • Distal section 113 has been, e.g., heated and bent to form loop 114 in its relaxed configuration.
  • catheter 110 is threaded onto a guidewire (not shown) , which holds distal section 113 in a configuration generally coaxial with the guidewire.
  • the guidewire may be partially withdrawn to permit distal 32
  • transition section 112 may be perforated to provide apertures 115 for fluid communication between central passageway 116 of catheter 110 and the outside of the catheter. Apertures 115 may be used for, e.g., the dispensing of a dye for fluoroscopic viewing of the bodily passage.
  • the, invention can be employed to produce soft-tip catheters, catheters of varied colors and for "strain-relief" of any part of a catheter.
  • a short differential stiffness section of the catheter is formed at the proximal end to provide a transition from the connector, for example, to which the tubing is attached and the main portion of the proximal end of the catheter.
  • a separate short piece of differential stiffness tubing can be used to provide improved strain relief to a known tubing/connector assembly.
  • a strain relief insert of this type is shown in Fig. 14.
  • tubular strain relief insert 123 which is a length of differential stiffness tubing, jackets flexible shaft 121 in the area of joint 124 between shaft 121 and fitting 122. Portion 125 of stiff second section 126 of strain relief insert 123 is disposed between shaft 121 and fitting 122, while the remainder of second section 126, transition section 127, and soft first section 128 of insert 123 extend distally about shaft 121, providing graduated flexibility to joint 124 to prevent kinking of the joint.
  • Soft tip guiding catheter 130 includes proximal section 131, transition section 132, and distal section 133.
  • Transition section 132 has been, e.g., heat treated to form S-shaped portion 134 for maneuverability of the catheter, while short distal section 133 provides , low-trauma soft tip 135 for the catheter.
  • stiffer proximal section 131 has been reinforced with a metal braid jacket (not shown) embedded in the wall of proximal section 131. Such an embedded metal braid jacket is described further below.
  • Fig. 10 illustrates "bump" tubing in which the insert end is of stiffer material and the bell end is of soft material. Unlike bump tubing produced using prior art methods where both ends are soft, the stiff insert end of the tubing produced by the invention provides for a more secure and tighter fitting connection. Also, the invention can be used to produce a new tubing for quick connect fittings in which the ends are of stiff material but alternating sections are of a softer material to provide flexibility for the length of tubing between the fittings while the stiff ends are easier to fit into quick connect fittings. A tubing of this type is shown in Fig. 11.
  • the tube includes several stiff first sections, each pair of first sections having a soft second section therebetween. Each stiff section is joined to an adjacent soft section by a transition section to form a continuous unbroken tube of differential stiffness without abrupt joints. Alternatively, only the ends of the tubing may be formed of stiff first sections, while a single long soft section may extend therebetween.
  • the tubing of Fig. 11 may be provided in a long length for cutting at the center of any of its stiffer sections , to provide a shorter length of soft, flexible tubing with stiff ends suitable for inserting into quick connect fittings.
  • Fig. 16 shows another product of the invention, coated guidewire 140 for use with a medical catheter.
  • Coated guidewire 140 includes guidewire 141 jacketed with differential stiffness tubing 142 along part or all of its length, stiffer proximal section 143, transition section 144, and softer distal section 145 of tubing 142 providing differential stiffness to coated guidewire 140.
  • Wire 141 may be a single filament wire.
  • guidewire 141 has proximal end 146 of uniform stiffness throughout its length and distal end 147 tapered to decrease its stiffness in the distal direction. As shown in Fig.
  • jacket 142 may be applied with increasing thickness in the distal direction to lessen the diameter difference between the wire proximal end 146 and wire distal end 145, and preferably to provide a uniform or near-uniform outer diameter along the length of guidewire 140.
  • the differential stiffness tubing described herein also may be utilized to jacket a cable to provide differential stiffness to the cable.
  • SCTS This technique is thus named "SCTS" technology.
  • nylons polyamides
  • HOPE'S polyesters
  • polypropylenes polypropylenes
  • other materials including mineral and fiber-filled materials
  • ethylene vinyl acetate, ethylenic copolymers, polyamide elastomers, polyurethanes and other thermoplastic elastomers can be used.
  • the tubing is for a medical catheter requiring a guidewire
  • many of the above listed materials for the stiff layer can be used for the inside layer that will come into contact with the guidewire, especially if the material is combined with current orientation technology to provide a low-friction surface.
  • all resins can be filled with radio opacity or not depending upon the intended use of the finished product.
  • good adhesion between layers is necessary while in other applications that is not a requirement. In either case, the invention can be used.
  • Another advantage of the invention is the versatility that it provides. Because the principles of the invention can be used to produce tubing in a continuous reel, the principles can be combined with other technologies to enhance the properties of the finished product. For example, tapering combined with lumen air control has been successfully employed to vary I.D., O.D. or wall thickness in some sections of a catheter. In particular, the invention can be used to produce microcatheters with a desired tip section having a thinner wall and smaller O.D. but with only a very slightly smaller I.D. Braiding of metal and non-metal wires can also be used with products produced by the invention to give the finished product more torqueability, higher stiffness, etc., and wire winding can be added to give additional kink resistance. Such tubings are illustrated in Figs.
  • Fig. 17, not drawn to scale shows metal braid reinforced tubing 150 made up of differential stiffness tubing 151 and metal mesh or braid 152 to provide a reinforcing sleeve over tubing 151.
  • braid 152 is shown as forming a sleeve over only proximal section 153 of the tubing.
  • braid 152 may extend distally from proximal section 153 to provide reinforcement to transition section 154 and, if desired, part or all of distal section 155.
  • Fig. 18, not drawn to scale similar features to those shown in Fig. 17 are indicated by the same reference numerals.
  • Fig. 18 shows similar features to those shown in Fig. 17 are indicated by the same reference numerals. Fig.
  • wire wound tubing 156 made up of differential stiffness tubing 151 and metal wire 157 wound around tubing 151 to provide reinforcement.
  • wire 157 is shown as being wound over only proximal section 153 of the tubing.
  • wire 157 may extend distally from proximal section 153 to provide reinforcement to transition section 154 and, if desired, part or all of distal section 155.
  • Either reinforced tubing 150 or 156 may be, e.g., heat treated to embed braid 152 or wire 157 in the outer, surface of the tube wall, as shown for reinforced tubing 150.
  • irradiation and orientation technologies can be employed along with the invention to produce tubing of higher strength, more dimensional stability, lower elongation, etc. The latter is beneficial to prevent neck-down of catheters that results in clamping of the catheter onto the guidewire when subjected to axial stress during a medical procedure.
  • Plastic foam technologies can also be employed with the method of the invention to produce super-soft tips.

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Abstract

Tête de co-extrusion (20) sans pièces mobiles et système comprenant la tête, chacun étant conçu pour fabriquer, p.ex. des tubes de rigidité différente. Dans la section intermédiaire du tube, la paroi du tube passe graduellement d'une première résine à une seconde résine afin de former un tube continu, sans cassures et sans jonctions brusques. La tête de co-extrusion comprend un corps formant un premier canal d'écoulement (38), un second canal d'écoulement (44) et un canal d'écoulement (51) commun, chacun possédant une extrémité en amont et une extrémité en aval. Les extrémités en aval des premier et second canaux débouchent dans l'extrémité amont du canal d'écoulement commun. Le corps définit également un premier orifice d'admission (32) servant à introduire la première résine dans l'extrémité en amont du premier canal, et un second orifice d'admission (34) pour introduire la seconde résine dans l'extrémité en amont du second canal, et une sortie (52) pour évacuer les résines de la tête de co-extrusion (20). La tête de co-extrusion (20) comprend également une matrice (40) étroitement ajustée à la sortie, et un embout (42). Le volume des résines en contact se trouvant dans le canal d'écoulement commun est sélectionné pour déterminer la longueur de la section intermédiaire du tube. Le système de co-extrusion comprend la tête de co-extrusion décrite ci-dessus et un dispositif modulateur pour réguler l'écoulement de la seconde résine dans le second orifice d'admission.
PCT/US1995/004105 1994-04-20 1995-04-03 Tete et systeme d'extrusion Ceased WO1995029051A1 (fr)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29615956U1 (de) * 1996-08-28 1996-11-21 Auch, Dietmar, 73773 Aichwald Mehrschichtige fast einem steifen Tuch ähnliche Dekorfolie aus Kunststoff-Lackfolie
WO2002036194A3 (fr) * 2000-11-06 2002-08-15 Advanced Cardiovascular System Tige de catheter comprenant des couches d'epaisseurs variables et procede de fabrication
US6776945B2 (en) 2001-07-03 2004-08-17 Scimed Life Systems, Inc. Medical device with extruded member having helical orientation
US7037345B2 (en) 2001-10-16 2006-05-02 Boston Scientific Scimed, Inc. Medical stent with variable coil and related methods
WO2006055203A1 (fr) * 2004-11-12 2006-05-26 Boston Scientific Limited Modification de surface selective d'une tubulure de catheter
US7128862B2 (en) 2001-07-03 2006-10-31 Scimed Life Systems, Inc. Biaxially oriented multilayer polymer tube for medical devices
US7291180B2 (en) 2001-04-02 2007-11-06 Boston Scientific Scimed, Inc. Medical stent and related methods
US7410602B2 (en) 1998-02-24 2008-08-12 Namic/Va, Inc. High flow rate dialysis catheters and related methods
EP2869882B1 (fr) 2012-07-05 2018-02-28 Abbott Cardiovascular Systems Inc. Cathéter à tige monolithique à deux lumières
KR101922800B1 (ko) 2017-03-24 2018-11-27 이제권 벌룬 카테타 제조방법

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JPS642658A (en) * 1987-06-25 1989-01-06 Terumo Corp Multi-cavity catheter and its preparation
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DE4032869A1 (de) * 1990-10-17 1992-04-23 Gercke Hans Hermann Verfahren zur herstellung von kathetern
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US4330497A (en) * 1981-01-19 1982-05-18 Sherwood Medical Industries Inc. Method of making grooved plastic medical tubing
EP0236645A1 (fr) * 1985-12-18 1987-09-16 Societe Alphacan Appareillage et procédé pour l'extrusion de tubes plastiques à parois composites
JPS642658A (en) * 1987-06-25 1989-01-06 Terumo Corp Multi-cavity catheter and its preparation
JPH02280765A (ja) * 1989-04-24 1990-11-16 Hitachi Cable Ltd カテーテルならびにその製造方法および装置
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DE4032869A1 (de) * 1990-10-17 1992-04-23 Gercke Hans Hermann Verfahren zur herstellung von kathetern
EP0618059A1 (fr) * 1993-03-31 1994-10-05 Cordis Europa N.V. Procédé de fabrication d'un profile éxtrudé avec caractéristiques variables dans la direction longitudinale et cathéter fabriqué suivant ce procédé

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29615956U1 (de) * 1996-08-28 1996-11-21 Auch, Dietmar, 73773 Aichwald Mehrschichtige fast einem steifen Tuch ähnliche Dekorfolie aus Kunststoff-Lackfolie
US7410602B2 (en) 1998-02-24 2008-08-12 Namic/Va, Inc. High flow rate dialysis catheters and related methods
WO2002036194A3 (fr) * 2000-11-06 2002-08-15 Advanced Cardiovascular System Tige de catheter comprenant des couches d'epaisseurs variables et procede de fabrication
US6663614B1 (en) 2000-11-06 2003-12-16 Advanced Cardiovascular Systems, Inc. Catheter shaft having variable thickness layers and method of making
US7291180B2 (en) 2001-04-02 2007-11-06 Boston Scientific Scimed, Inc. Medical stent and related methods
US7128862B2 (en) 2001-07-03 2006-10-31 Scimed Life Systems, Inc. Biaxially oriented multilayer polymer tube for medical devices
US6776945B2 (en) 2001-07-03 2004-08-17 Scimed Life Systems, Inc. Medical device with extruded member having helical orientation
US7037345B2 (en) 2001-10-16 2006-05-02 Boston Scientific Scimed, Inc. Medical stent with variable coil and related methods
WO2006055203A1 (fr) * 2004-11-12 2006-05-26 Boston Scientific Limited Modification de surface selective d'une tubulure de catheter
US7951116B2 (en) 2004-11-12 2011-05-31 Boston Scientific Scimed, Inc. Selective surface modification of catheter tubing
US8777928B2 (en) 2004-11-12 2014-07-15 Boston Scientific Scimed, Inc. Selective surface modification of catheter tubing
US9132257B2 (en) 2004-11-12 2015-09-15 Boston Scientific Scimed, Inc. Selective surface modification of catheter tubing
EP2869882B1 (fr) 2012-07-05 2018-02-28 Abbott Cardiovascular Systems Inc. Cathéter à tige monolithique à deux lumières
EP3329958B2 (fr) † 2012-07-05 2022-08-31 Abbott Cardiovascular Systems Inc. Cathéter à tige monolithique à deux lumières
KR101922800B1 (ko) 2017-03-24 2018-11-27 이제권 벌룬 카테타 제조방법

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