(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2001/0044633 A1
`Klint
`(43) Pub. Date:
`Nov. 22, 2001
`
`US 20010044633A1
`
`(54) ENDOVASCULAR MEDICAL DEVICE WITH
`PLURALITY OF WIRES
`
`(76) Inventor: Henrik Sonderskov Klint, LYngby
`(DK)
`Correspondence Address:
`Anton P. Ness
`Patent Attorney
`P.O. BOX 2269
`Bloomington, IN 47402-2269 (US)
`(21) Appl. No.:
`09/770,417
`(22) Filed:
`Jan. 26, 2001
`(30)
`Foreign Application Priority Data
`
`Publication Classification
`(51) Int. CI.7.
`... A61M 25/00; A61M 29/00
`(52) U.S. Cl. ............................................ 606/200, 604/527
`(57)
`ABSTRACT
`An endovascular device (1,100,200,300) having a distal end
`(2), a proximal end (4) and a body portion (3) therebetween.
`The body portion is made of a multiple filament helically
`wound row (A) of wires (5), provided with a Sealing coating
`(14) on the inside surface or the outside surface or both. The
`device may be a catheter (1), a sheath, an introducer, a
`delivery device, a pusher (100), an embolization coil deliv
`ery device (300), or a receptacle (208) for an expandable
`prosthesis (220) used with a delivery device(200). From 2 to
`12, and preferably from 4 to 8, wires (5) are used in the row,
`and fewer wires may be used proceeding toward the distal
`end (2) for greater flexibility. The helically wound row of
`
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`while resisting kinking, and enables a Small outside diameter
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 1 of 24
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`

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`Patent Application Publication Nov. 22, 2001 Sheet 1 of 10
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 2 of 24
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`

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`Patent Application Publication Nov. 22, 2001 Sheet 2 of 10
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`US 2001/0044633 A1
`
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 3 of 24
`
`

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`Patent Application Publication Nov. 22, 2001 Sheet 3 of 10
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`US 2001/0044633 A1
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 4 of 24
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`Patent Application Publication Nov. 22, 2001 Sheet 4 of 10
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 5 of 24
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`Patent Application Publication Nov. 22 , 2001 Sheet 6 of 10
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 7 of 24
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`

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`Patent Application Publication Nov. 22, 2001 Sheet 7 of 10
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`US 2001/0044633 A1
`
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 8 of 24
`
`

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`Patent Application Publication Nov. 22, 2001 Sheet 8 of 10
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 9 of 24
`
`

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`Patent Application Publication Nov. 22, 2001 Sheet 9 of 10
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`US 2001/0044633 A1
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 10 of 24
`
`

`

`Patent Application Publication Nov. 22, 2001 Sheet 10 of 10
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`US 2001/0044633 A1
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`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 11 of 24
`
`

`

`US 2001/0044633 A1
`
`Nov. 22, 2001
`
`ENDOWASCULAR MEDICAL DEVICE WITH
`PLURALITY OF WIRES
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`0001. This application claims priority of the following
`European applications:
`0002)
`Ser. No. 00610012.7 filed Jan. 28, 2000
`0003)
`Ser. No. 006100 13.5 filed Jan. 28, 2000
`0004)
`Ser. No. 00610014.3 filed Jan. 28, 2000
`0005)
`Ser. No. 00610015.0 filed Jan. 28, 2000
`
`TECHNICAL FIELD
`0006 The present invention relates to the field of medical
`devices and more particularly to vascular devices Such as
`catheters and delivery Systems for implantable devices.
`
`BACKGROUND OF THE INVENTION
`0007 Catheters for medical diagnostic or therapeutic use
`are well known. A catheter has a distal end and a proximal
`end, with a body extending therebetween and a lumen
`extending therethrough from end to end. A wide variety of
`catheters exists for percutaneous insertion by the Seldinger
`technique into the vascular System to accomplish diagnostic
`or therapeutic objectives. The vessels of the peripheral
`vasculature have a relatively large diameter and low tortu
`osity, the coronary vasculature is Somewhat Smaller and
`more tortuous, and the vasculature in the Soft tissue of the
`brain and liver is of Small lumen and is very tortuous.
`0008. In order to be able to access the various parts of the
`vasculature, the catheter needs to be flexible and to maintain
`its column Strength when it follows a tortuous path. The
`contradictory requirements for flexibility and column
`Strength are particularly pronounced in catheters for intrac
`ranial catheterizations used in a variety of diagnostic and
`interventional neurological techniques including delivery of
`contrast fluids, drugs or a vasoocclusive agent, treatment of
`tumors, aneurysms, AVS (arteriovenous shunts) and So forth.
`0009. When a central member is to be moved within a
`catheter or sheath to perform an activity at or beyond the
`distal end of the catheter, after the catheter has been posi
`tioned, the central member is to be pushed through the
`catheter lumen. The more tortuous the path and the Smaller
`the catheter the more difficult it is to advance the central
`member through the catheter lumen. This difficulty is in
`particular pronounced in coaxial Systems for intracranial
`use. Where the central member is a delivery device for an
`embolization coil and must be rotated to disconnect from the
`coil upon release at the treatment Site, the central member
`must be capable of transmitting torque to its distal end for
`assured coil disconnection; one Such prior art coil delivery
`system is disclosed in U.S. Pat. No. 5,122,136; but it is a
`common problem that Such prior art coil delivery members
`have relatively high rigidity which is problematic in Small or
`tortuous vessels with aneurysms. Where the device is a
`pusher to push a device Such as a Stent from the distal end
`of the catheter, the pusher must have Substantial column
`Strength as well as great flexibility.
`
`0010 Where a catheter is to be used for delivery of an
`endovascular prosthesis to a treatment Site, Such as a Stent,
`a Stent graft, a valve member, or a filter, where the prosthesis
`is compressed to pass through the catheter and then SelfeX
`pand upon release therefrom within a body lumen, the
`prosthesis must be constrained while within the catheter and
`imposes significant forces against the Surrounding catheter
`body.
`0011. It is an objective of the present invention to provide
`a medical device that includes a distal area that is very
`flexible and yet easily pushable and capable of transferring
`torque in an assured, controllable manner.
`0012. It is another objective to provide a catheter system
`that makes it easier to advance the central member through
`the catheter also in cases where the catheter exhibits Sharp
`turns.
`0013. It is further an objective to provide a catheter that
`resists the Substantial radially outward forces of a com
`pressed endovascular prosthesis contained within the distal
`end thereof, and yet be very flexible and capable of trans
`ferring torque.
`0014.
`It is yet another objective to provide a central
`member for movement within a catheter lumen that is very
`flexible, has Substantial column Strength and/or is capable of
`transferring torque.
`
`SUMMARY OF THE INVENTION
`0.015 The foregoing and other problems are solved and a
`technical advance is achieved in an illustrative medical
`device for passage along the vasculature of a patient, having
`a body portion comprising primarily a plurality of coils or
`turns of a plurality of wound filaments or wires. The medical
`device may be a catheter or may be one or more components
`of a delivery System for endovascular devices, Such as a
`central member within a catheter, for example, a pusher or
`delivery device for an embolization coil. Two to twelve
`filaments Such as wires, and preferably from four to eight
`wires, are preferably helically wound adjacent to each other
`as a group or row with a pitch corresponding generally to the
`aggregate width of the adjacent wires in the row.
`0016. The wound wires transfer torque and also force
`components directed in the axial direction of the medical
`device to the distal end thereof, and this construction is
`found to give a very high resistance to kinking of the
`medical device. When a catheter according to the present
`invention is heavily bent, the cross-section of the catheter
`maintains a circular shape. This provides a distinct advan
`tage over prior art catheters which are deformed into an Oval
`shape in cross-section when bent leading to kinking. The
`catheter Surprisingly maintains its capabilities for transfer
`ring torque and push when it follows a tortuous path
`involving two or more loops, probably because of the
`excellent kinking resistance. These qualities facilitate place
`ment of the catheter at the desired position in the vascular
`System, and by making the catheter System So that the inner
`Surface of the catheter is mainly undeformable by a central
`member moving axially there within, it is virtually impos
`Sible for the central member to get Stuck in the catheter wall,
`even in situations where the catheter is heavily curved. This
`is in contrast to prior art coaxial Systems where the catheter
`is made of a Soft material Such as a resin, the inner Surface
`
`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 12 of 24
`
`

`

`US 2001/0044633 A1
`
`Nov. 22, 2001
`
`of which is readily deformable in a local area, causing the
`formation of a small bead in front of the tip of the central
`member bearing against the wall of the curved catheter. It is
`an advantage of the catheter according to the present inven
`tion that the wall is primarily made of wires that provide a
`hard and relatively Slippery inner Surface resulting in low
`resistance to advancing the central member through the
`lumen of the catheter.
`0.017. The inventive catheter maintains three valuable
`characteristics of very high flexibility, pushability and
`torqueability even when Set in a very tortuous pattern
`involving two or more tight loops, and the catheter can thus
`be of use in very Small and distant vessels. Such as deep brain
`Sites accessed by intracranial catheterization. Preferably, a
`thin Sealing coating of elastic, low-friction material, or
`adhesive material may be provided over the outwardly
`directed Surfaces of the coiled wires or along the inner
`Surfaces that define a lumen, or at least in recesses between
`abutting wires or in interstices between nonabutting turns
`between the groups of wires, thus Sealing the interstices
`between the wires so that the catheter wall is leakproof
`especially where the device is a catheter or sheath.
`0.018
`Further, wires may have the same diameter in the
`group and extend the entire length of the device, or the
`device may have portions with wires of different diameters,
`lessening toward the distal end and thereby decreasing
`gradually in outer diameter; the device may also have a
`noncoiled part in the proximal region Such as a Supplemen
`tary cannula or tubing.
`0019. In the present context, the term “catheter' is to be
`understood in the Sense that it can be an ordinary catheter,
`but also a sheath, which is a short catheter, and in the latter
`case the central member can be a catheter, e.g., a catheter
`according to the present invention. The sheath can have a
`check-flow valve or a fitting at the proximal end in order to
`Stop bleeding out of the puncture Site. In one aspect, the
`catheter may be utilized without a guidewire. When intended
`for use in a Soft tissue region, it is preferred that the distal
`end of the catheter is provided with a buffer member, such
`as a soft obturator, that distributes the force from the catheter
`tip over a large area So that damage to the vascular wall is
`avoided. The term "central member” can be a member that
`Simply blocks the distal opening of the catheter during
`inflation of a balloon for percutaneous transluminal coronary
`angioplasty; it may also be an embolization means Such as
`a Sack containing Several occlusion coils, or a Stent for
`expansion on a balloon, a Sensor body for measuring pres
`Sure or temperature or the composition of blood, a physical
`shunt member, a retrieval wire or a forcepS used to retrieve
`another member from a vascular Site, or it can be a central
`member of Some other kind.
`0020. In another aspect, the number of wires may vary
`along the length of the catheter, Such as reducing the number
`of wires in the row during the winding operation in the distal
`direction, enabling a larger pitch angle and increasing the
`flexibility of the catheter proximate to the distal end.
`0021. In a second embodiment, the medical device may
`be a delivery System for a prosthesis Such as a Stent, a Stent
`graft, a valve member, or a filter, wherein the prosthesis is
`compressible to be placed within a receptacle at the distal
`end of the delivery catheter and is then radially expandable
`upon delivery to a treatment site after being urged from
`
`receptacle. The delivery System has a catheter Shaft with a
`receptacle that may be simply a distal end portion of the
`catheter shaft, but the receptacle may also be a separate
`tubular member that extends from the distal end of the
`catheter Shaft, or optionally partially within the distal end.
`The receptacle, whether integral with the catheter shaft or a
`Separate member, is primarily defined by a group of wires
`wound about a lumen, thus having the same advantageous
`properties of high flexibility and kink resistance as the
`catheter Shaft, optionally and preferably, when the recep
`tacle is a Separate member, the catheter Shaft may also be of
`the inventive type hereinbefore set forth. The receptacle may
`have a larger lumen dimension than the lumen of the catheter
`shaft, Such as by having a Smaller wall thickness through use
`of Smaller diameter wire or grinding away an innermost
`portion of the coiled wires of the distal tip when integral
`with the catheter shaft, Since the wall thickneSS required for
`resisting the outward pressure from the radially compacted
`prosthesis is Smaller than the wire thickneSS required to
`transmit axial thrust over a long Shaft distance, Such as 80
`cm or more, enabling the outer diameter to remain the same
`as that of the catheter Shaft portion.
`0022. In a third embodiment, a prosthesis receptacle is a
`Separate member and is fixed to the helically wound multiple
`filament row of wires of the catheter Shaft, in axial extension
`thereof. This allows the prosthesis receptacle to be designed
`and manufactured independently of the Shaft portion. The
`mounting in direct extension of the wire or wires of the
`catheter shaft makes the prosthesis receptacle follow tor
`Sional actions on the shaft portion. Although the prosthesis
`receptacle can be designed in any manner capable of resist
`ing the outward pressure applied to the inside of the recep
`tacle by the compressed prosthesis, it is preferred that the
`prosthesis receptacle be a tubular Segment of multiple fila
`ment construction, Such as a braided wire construction
`providing the prosthesis receptacle with a high flexibility.
`More preferably, the receptacle is a construction of a Second
`helically wound group or row of multiple wires; this makes
`it possible to obtain a very diminutive outer diameter as only
`a single layer of wires is required.
`0023. In yet another embodiment, the medical device
`may be a pusher for use in a delivery System of the type
`described above, where the pusher is primarily comprised of
`multiple wires that are helically coiled, resulting in a hollow
`construction with torqueability and pushability similar to the
`shaft portion of the delivery device and with slightly greater
`flexibility due to the smaller outer diameter of the row of
`wires.
`In still another embodiment, the medical device
`0024.
`may be used in an introducer for an embolization device,
`where the delivery member comprises primarily a plurality
`of wires to provide the advantageous torqueability of the
`present invention. The distal end of the delivery member
`thus is able to be rotated from rotation of the proximal end
`thereof, and thus being disconnectable through unscrewing
`from the embolization device, a technique that causes only
`negligible influence on the vasculature while enabling pre
`cise maintenance of the embolization device in its desired
`position during detachment even in very tortuous paths to
`treatment Sites Such as intracranial locations.
`
`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 13 of 24
`
`

`

`US 2001/0044633 A1
`
`Nov. 22, 2001
`
`BRIEF DESCRIPTION OF THE DRAWING
`0.025 Embodiments of the present invention will now be
`described by way of example with reference to the accom
`panying drawings, in which:
`0.026
`FIG. 1 is a side view of a catheter according to the
`present invention;
`0027 FIGS. 2 and 3 are enlarged partial views in lon
`gitudinal section of embodiments of the catheter in FIG. 1;
`0028 FIG. 4 is a partial view in longitudinal section of
`an embodiment where the number of wires in a row varies
`along the length of the catheter;
`0029 FIG. 5 is an enlarged partial and sectional view of
`the transition between two catheter Segments having wires
`of different diameter;
`0030 FIG. 6 is an enlarged view of an embodiment
`having a catheter tip with a buffer member;
`0.031
`FIG. 7 depicts a winding operation on a multiple
`wire row;
`0.032
`FIG. 8 depicts a catheter segment having decreas
`ing outer diameters,
`0033 FIG. 9 is an illustration of the catheter of FIG. 1
`in position in the vascular System;
`0034 FIG. 10 is an illustration of a device of the present
`invention used in a delivery System having a central member
`that Serves as a pusher,
`0035 FIGS. 11 and 12 are enlarged views of central
`members of FIG. 10 being advanced out of the distal end of
`the catheter;
`0036 FIG. 13 is an illustration of a delivery system of
`the present invention, for delivery of a prosthesis Such as a
`Stent,
`0037 FIGS. 14 to 18 are enlarged partial views in lon
`gitudinal Section of various embodiments of the delivery
`system of FIG. 13;
`0038 FIG. 19 depicts a partial view of a delivery mem
`ber of an embolization device introducer according to the
`present invention;
`0039 FIG. 20 is a sketch of the introducer of FIG. 19
`ready for disengaging an embolization device;
`0040 FIG. 21 is an enlarged illustration of the distal end
`of the delivery member of FIG. 20 with an embolization
`device during placement in a catheter;
`0041 FIGS. 22 and 23 are partial view of the delivery
`members of other embodiments of embolization device
`introducers,
`0.042
`FIG. 24 is an enlarged view of a coil connection
`means of FIG. 19;
`0043 FIGS. 25 and 26 are views of different embodi
`ments of embolization device introducers providing
`increased flexibility in the distal end area of the delivery
`member; and
`0044 FIG. 27 illustrates delivering an embolization
`device by the embolization device introducer of FIG. 19.
`
`DETAILED DESCRIPTION
`0045. In the following description of the depicted
`embodiments, the same reference numerals are used for
`features of the same type. FIGS. 1 to 12 illustrate luminal
`medical devices Such as catheters and sheaths, FIGS. 13 to
`18 illustrate prosthesis receptacles and delivery Systems
`therefore; and FIGS. 19 to 27 illustrate embolization device
`delivery Systems.
`0046 A vascular medical device according to the present
`invention and illustrated in FIG. 1 is generally denoted 1,
`and it has a distal end 2, a body portion 3 extending from the
`distal end to a proximal end 4. The body portion is made of
`a first helically wound multiple-filament Sequence, group or
`row of wires 5 and it has a central longitudinally extending
`lumen 6. The medical device may be a catheter, and a
`catheter is normally open ended at both the proximal and the
`distal end; but for Special uses Such as a Single lumen
`balloon dilatation catheter, the distal end can be provided
`with means for barring the distal end opening (see FIG. 6).
`0047 For example, a catheter according to the present
`invention can be a balloon dilatation catheter used for
`percutaneous transluminal coronary angioplasty, an angiog
`raphy catheter, a drug delivery catheter, a guiding catheter,
`an infusion catheter, and So forth.
`0048. The wires 5 used in the helically wound multifila
`ment group or row are of a linear elastic material, Such as
`Stainless Steel, titanium or tantalum, or it is made of a
`Superelastic alloy, Such as nitinol. Preferably, the wires have
`an ultimate tensile strength in the range of 1800 to 2700
`N/mm but lower or higher values are also possible. The
`body portion 3 of the catheter is made by placing a group of
`from two to twelve wires of desired wire diameter in a row
`next or closely adjacent to each other, whereafter the group
`of wires is wound according to the desired pitch angle in a
`common movement into the body portion. Because a row of
`wires is wound, an individual wire is restricted in movement
`by the other wires and is plastically deformed into a per
`manent helical shape which is kept without any further
`restraints other than the remaining wires in the row. The
`winding can be done on the inside end of a tubular Support
`member where the row of wires is inserted at said end by
`rotating and Simultaneously pushing the wires against the
`inside of the Support. The wound wire then exits at the other
`end of the support. This produces a wire body with a very
`precise outer diameter.
`0049. Alternatively, the winding operation can take place
`about a mandrel 7. FIG. 7 depicts a winding of a row A of
`four identical wires 5. After the winding the mandrel with
`the coiled wires can be Subjected to heat treatment in order
`to remove residual Stresses from the wires. AS an example
`the heat treatment can last for about two hours in an oven at
`a temperature of about 500 C. Generally, the temperature
`can be in the range of 400 to 600 C. and the holding time
`at the temperature can last for many hours, Such as up to 20
`hours or more. After the heat treatment the mandrel is
`removed from the wires. The wires in the resulting helically
`wound multiple-wire group maintain their mutual position
`even when heavily torqued, bent or pushed, presumably
`because each Single wire is Supported by the contiguous
`wires in the row. The winding operation can be effected So
`that the windings are touching each other, but preferably it
`is performed So that an interstice B is present between the
`
`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 14 of 24
`
`

`

`US 2001/0044633 A1
`
`Nov. 22, 2001
`
`turns (FIG. 2). The interstice facilitates bending of the body
`portion in tight turns along the vasculature Such as is shown
`in FIG. 9.
`0050. The size of the pitch angle a (FIG. 2) depends on
`the diameter of the wires, the diameter of the body portion
`3 and the number of wires in the row. The most preferred
`pitch angle a for the catheter is in the range of 40 to 68 or
`50 to 70. However, the combination of torque-transferral,
`pushability and transverse flexibility is normally well-bal
`anced for pitch angles in the range of 50 to 68. The
`diameter d of the wire is typically in the range of 0.03 to 0.75
`mm, and preferably in the range of 0.15 to 0.45 mm. The
`present invention includes providing a medical device hav
`ing different Segments wherein the row of wires is Set to
`different pitch angles, or wherein different rows of wires
`have different pitch angles.
`0051. In order to make the tip portion of the catheter more
`Visible on a Screen it is desirable to use Some kind of
`radiopaque material, Such as platinum or gold. It can be of
`annular shape and be located at a predetermined distance
`from the distal end 2, or the terminal end of the distal tip of
`the catheter can be provided with a marker means for
`making it radiopaque, Such as a gold layer or a gold thread.
`0.052 The catheter can be made with a uniform diameter
`throughout its length. In case the catheter has a diminishing
`diameter towards the distal end, a prefabricated catheter of
`uniform diameter can be ground to the desired dimensions.
`0053 As an alternative or supplement to grinding, the
`catheter can be composed of Several Segments in which the
`wires have mutually different diameters and cross-sectional
`areas. In a proximal Segment 8 the wires can have a larger
`diameter than the wires in a distal Segment 9. The Segments
`can be joined together in axial eXtension by laser welding 10
`as depicted in FIG. 5, by soldering, by bracing or in another
`manner Such as mutual geometrically locking of the wires in
`the Segments or by mechanical locking, Such as preSS-fitting
`one Segment into the lumen of the other Segment, or binding
`the Segments in axial extension with threads or Suture.
`0.054 When the catheter body is of multi-segment con
`Struction, the inner lumens of the Segments are preferably of
`even size which brings the advantage that an advancing
`guidewire can not Snag or grip onto a step in the inner wall
`of the body portion.
`0055. In the embodiment illustrated in FIG. 4, the num
`ber of wires in Said helically wound group or row of wires
`varies along the length of the catheter. During the winding
`operation the number of wires in the row is reduced one by
`one at the points in time where the individual Segment
`having a certain number of wires has obtained the desired
`length. The segment marked “VI' has six wires in the row,
`and the segments marked “V”, “IV” and “III' have five, four
`and three wires, respectively, in the row. Each time a wire is
`left out of the row, the pitch gets shorter and the pitch angle
`grows resulting in an even more flexible consecutive Seg
`ment. The advantage of this embodiment is that the wires
`extending into the distal end Segment are continuous from
`the distal end to the proximal end of the catheter, thus
`avoiding any need for joining the various Segments. It is
`possible to Secure the wire ends of the discontinuous wires
`onto the other wires, Such as by welding, Soldering or the
`like.
`
`0056. A grinding procedure can also be used to produce
`one or more tapered segments 11 in the body portion 3 (FIG.
`8). The taper can extend along a Substantial length of the
`body portion. In the tapered Segment the outer diameter of
`the catheter diminishes toward the distal end. Due to the
`taper, the catheter obtains a gradually increasing transverse
`flexibility and a higher Softness, but column Strength and
`torque are nevertheless Surprisingly transferred to the distal
`end.
`0057 When the catheter is to be advanced without a
`guidewire, the distal end 2 can be provided with a soft buffer
`12, as shown in FIG. 6, having a rounded distal end which
`acts gently on the vascular wall when the catheter is pushed
`forwardly. A thread 13 can be securely embedded into the
`soft pliable material of buffer 12 and be ensnared around one
`of the distal wires, so that the thread will keep the buffer
`connected to the catheter body portion when the buffer is
`pushed out and cleared from the lumen of the catheter.
`0.058
`Referring now to FIG. 3, the wound wires 5 are
`provided with a Sealing coating 14 on the inside, or on the
`outside or on both, Surfaces of the catheter body. The coating
`is relatively thin and is preferably made of an elastic material
`which can be hydrophilic. The coating extends along the
`entire length of the catheter and is typically applied after
`winding and heat treatment of the catheter body have been
`completed. AS an example, the coating can be of PTFE
`applied onto the outside Surface of the body portion in the
`Same manner as Such a coating is traditionally applied onto
`the exterior of a guidewire. When the coating is to be applied
`on the external and the internal Surfaces of the body portion
`the catheter length can be dipped briefly into a bath of liquid
`coating material, which is then allowed to Solidify following
`removal from the bath.
`0059. In case it is desirable to use a hydrophilic coating,
`the coating can comprise a hydrophilic polymer Selected
`from the group comprising polyacrylate, copolymers com
`prising acrylic acid, polymethacrylate, polyacrylamide,
`poly(Vinyl alcohol), poly(ethylene oxide), poly(ethylene
`imine), carboxymethylcellulose, methylcellulose, poly
`(acrylamide Sulphonic acid), polyacrionitril, poly(Vinyl pyr
`rolidone), agar, dextran, dextrin, carrageenan, Xanthan, and
`guar. The hydrophilic polymers can comprise ionizable
`groupS Such as acid groups, e.g., carboxylic, Sulphonic or
`nitric groups. The hydrophilic polymers may be croSS-linked
`through a Suitable cross-binding compound. A cross-binder
`generally comprises two or more functional groups which
`provide for the connection of the hydrophilic polymer
`chains. The actually-used croSS-binder depends on the poly
`mer System: if the polymer System is polymerized as a free
`radical polymerization, a preferred croSS-binder comprises 2
`or 3 unsaturated double bonds.
`0060. By making the inventive device primarily of a
`group or row of two or more wires, which row is helically
`wound with a pitch roughly corresponding to the aggregate
`width of the adjacent wires in the row, the wound wires
`transfer torque and also force components directed in the
`axial direction of the catheter to the distal end thereof, and
`this construction is found to give a very high resistance to
`kinking of the device. When the device is heavily bent the
`croSS-Section of the device maintains a circular shape, and
`the forces transmitted through the helically wound wires
`have less tendency to be concentrated in the area of the bend.
`
`Edwards Lifesciences Corporation, et al. Exhibit 1019, p. 15 of 24
`
`

`

`US 2001/0044633 A1
`
`Nov. 22, 2001
`
`This is a distinct advantage over prior art devices of the type
`that define a lumen (e.g., catheters and sheaths), which are
`deformed into oval shape when bent, and thus they are much
`more prone to kinking. The device Surprisingly maintains its
`capabilities for transferring torque and push when it follows
`a tortuous path involving two or more loops, probably
`because of the excellent kinking resistance, and in curved
`areas the torque and push is mainly transmitted within the
`device resulting in a favorably low influence on the vascular
`walls.
`0061 Due to the very high flexibility, pushability and
`torqueability and the ability of the construction of the
`inventive device to maintain each of these three character
`istics even when Set in a very tortuous pattern involving two
`or more tight loops, the device can be of use in very Small
`and distant vessels. Such as deep brain Sites accessed by
`intracranial catheterization.
`0062) If required, the flexibility of the distal portion of a
`luminal device during advancement along a tortuous path,
`can be further increased by avoiding the use of a guidewire.
`The body portion of a catheter, for example, can be maneu
`Vered to the desired prosthesis deployment site like a
`guidewire because it is made of the multiple wire coils So in
`terms of maneuverabili