CA2184484A1

CA2184484A1 - Catheter guidewire with radiopaque markers

Info

Publication number: CA2184484A1
Application number: CA002184484A
Authority: CA
Inventors: Richelle Tartacower; Lex Jansen; Joanne Gilbert; Rebecca C. Testa
Original assignee: Individual
Current assignee: Medtronic Vascular Inc
Priority date: 1994-03-11
Filing date: 1995-03-09
Publication date: 1995-09-14
Also published as: DE69517518D1; EP0749334A1; JPH09510125A; DE69517518T3; WO1995024237A2; DE69517518T2; US5606981A; EP0749334B2; WO1995024237A3; EP0749334B1

Abstract

A guidewire for use with a catheter has varying radiopacity as well as at least one radiopaque marker in its distal end. In one embodiment, the guidewire includes a shaft having a distal radiopaque coil supported by and attached to a distal portion of the shaft and a proximal radiopaque coil supported by and attached to an intermediate portion of the shaft. The proximal and distal coils are spaced apart from one another. The distal coil may be more radiopaque than or equally radiopaque to the proximal coil such that when viewed under fluoroscopy, the highly radiopaque coil will define a dark image whereas the more proximal radiopaque coil will define a moderately radiopaque image or both will define a dark image. The area between the two coils will appear white. Between the coils, at least one radiopaque marker band is attached to the shaft. The marker bands provide several reference lengths for a physician. A polymer sleeve encases the marker bands and the shaft between the first and second coils providing a uniform outer diameter to the distal region of the guidewire. In another embodiment, the proximal coil of the first embodiment is absent and the polymer sleeve extends proximally of the radiopaque marker bands. In a further embodiment, a radiopaque coil having varying pitch along its length is supported by and attached to a distal region of the core wire.

Description

wo 9sl2~237 ,, ~ ~ PCT~rS95/03076 t~AT~T~TF~R ~:rU.~ ,Wlh'~ NIT~T RAT)IOppt~uE MARR~RR
RF~T.~TT"n AppTlT(~z~TIoN
This application is a rrlntlnll~tion-in-part of application Serial No. 08/212,558, filed March ll, 1994.
FJ~T n OF T~T~ IN~ENTION
The invention relates to guidewires used to support and guide dilatation catheters as they are advanced through body lumens such as blood vessels.
R(.RO~lNn OF T~ INVENTI( 1N
A wide variety of guidewires are used for various medical purposes in the treatment of the human body. Typically guidewires are used to guide a catheter to a site within a patient ' s blood vessel to perform the procedure for which the catheter is adapted. For e~mple, guidewires, particularly small diameter steerable guidewires, perform the important function in percutaneous transluminal coronary a~gioplasty of guiding a balloon catheter such that the balloor~ can be placed at the s~te of the stenosis (obstruction) to be treated. The balloon is then inflated to dilate the stenosis and subsequently increase the blood f low through the artery .
SUBSTITUTE SHEET (RUI E 26) W095/21237 2 } 8 4 4 8 4 r ~ 03Q76 Typical angioplasty steerabie guidewires include a torsionally rigid, longitudinaliy flexible shaft and a f lexible distal end that includes a coil, all or part of which may be radiopaoue, so that a physician can monitor fluoroscopically the position and advancement of the guidewi re .
During procedures, such as coronary angioplasty, it is often the practice to inject a radiopaque contrast liquid into the artery so that the shape and path of the artery, particularly in the region of the stenosis, may be visualized 1uoroscopically. The radiopacity of some guidewire coils may be so dense as to visually obstruct the stenosed part of the artery when the contrast liquid is injected. As a result of the visual obstruction, the ability of the physician to visualize and assess the nature of the stenosis is impaired.
U.S. Patent No. ~,144,959 (Gambale) describes a guidewire which does not visually obstruct the desired part of the artery when contrast liquid is injected. The distal region of the Gambale guidewire includes a coil having a highly radiopaque distal portion, a moderately radiopaque proximal portion and a non-radiopague ; nt~ ate portion . The guidewire may be advanced so that its distal portion advances through and beyond the stenosis while the non-radiopaque portion is disposed at the region of the stenosis to prevent visual obstruction. The moderately radiopague proximal portion provides an indication of the position and configuration of the more proximally located portions of the guidewire. Thorough assessment of the stenosis, however, is difficult without ~he provision of a visual reference len-gth.
SU~SrIME SHEET (RULE 26~

~r, ~. ` y<~',' advanced 80 that its distal portion advances through and beyond the stenosis while the non-radiopa~ue portion is disposed at the region o~ the stenosis to prevent vi~ual obstruction. The moderately radiopa~ue proximal portion provides an indication of the position and configuration of the more proximally located portions of the guidewire.
Thorough assessment of the stenosis, however, is difficult without the provision of a visual reference length .

AMENDED SHEET
IPEA/EP

~'0 '~ 3~ PCT~IS9~ 3()7~
3 2 1 ~3 4 4 8 4 The proYisiOn o~ a visible reference length would enable the physician to make in vivo measurements of the lesion to determine its length and shape and dimensions o~ the artery ad~acent to the lesion. The assessment facilitates the selection of an appropriately sized balloon catheter anl, additionally, in the event that a stent is needed to prevent the artery from collapsing in the area of the lesion, aids in the selection of an appropriately sized stent. It is, therefore, desirable for the distal region of non-obstructin~
guidewires to include a highly radiopaque distal section and more proximal uniformly spaced radiopaque markers, which provide such a reference length.
It is among the gene~al objects of the invention to provide guidewires having the foregoing desirable characteristics .
S~RY aF THE INVENTION
A guidewire, in accordance ~ith the invention, has an elongate f lexible shaft . In a f irst ~ of the invention, a distal radiopaque coil is ~ uL~ed about and is att~rhod to a distal portion of the shaft. A prûximal radlopaque coil is supported about and is attached to a distal portion of the shaft, spaced proximally from the distal coil. The distal coil may be more rA~l~oF~u~ than the proximal coil which would make it appear darker than the proximal coil under fluoroscopy. The two coils may have identical radiopacity. A polymer sleeve encases the shaft between the distal and proximal coils, its ends overlapping the proximal end of the distal coil and the distal end of the SU8STlTllTE SHEET (RUL 26) wo 9sl2~37 PCTIUS95/03076 1 8 4 4 8 4 o proximal coil. The guidewire also includes at least one radiopague marker band attached to the shaf t between the distal and proximal coils and encased by the polymer sleeve.
Thus, the guidewire provides a distal region having a highly radiopague distal portion, a non-radiopaque intermediate portion (except for the radiopaque markers), and a moderately or highly radiopaque proximal portion.
In a second ~ of the invention, a radiopaque coil is supported about and is attached to the distal portion of the distal region of the shaft. At least one radiopaque marker band is attached to the proximal portion of the distal region of the shaft. A polymer sleeve encases the marker bands and the proximal portion of the distal region of the shaft. In this embodiment, the guidewire provides a distal region having a highly radiopas~ue distal portion and a non-radiopaque proximal portion (except for the radiopaque markers ) .
In a third embodiment of the invention, a radiopaque coil is supported about and is attached to the distal region of the shaft. The coil has varying pitch along its length and includes highly radiopaque distal and proximal sections and a moderately radiopague ;nter ~l;ate section. The guidewire may also include an additional small radiopa~aue coil attached to the distal end of the guidewire and located within the distal section of the coil for increased radiopacity in the distar section. The intermediate section may include one or more tightly wound coil sections. Each coil section appears as a dark marker under fluoroscopy, and is separated from the proximal and distal sections by loosely wound coil sections, which appear lighter under fluoroscopy. A polymer sleeve SUBSTITUTE SHEET (RULE 26) wo gsl2~237 ~ ~ ~ " ~ , 2 1 8 4 4 8 4 PC rlUsgs/03076 encases the coil along a majority of the length of the coil.
Thus, the guidewire provides a distal region having highly radiopaque distal and proximal portions and a very lightly radiopaque inte -~liate portion (except for the darker radiopaoue markers ) .
In a fourth em~odiment of the invention, a radiopaoue coil is supported about and is attached to the distal region of the shaft. The coil has varying pitch along its leng~h and includes highly radiopaque distal and proximal sections and a lightly radiopaque intermediate window section. The int~ -~iatp window section may include one or more smaller tightly wound coil sections separated by loosely wound coil sections. Each smaller tightly wound coil section appears as a dark marker under f luoroscopy. A polymer sleeve encases the int~ te window section of the coil. The sleeve is attached to the guidewire only at the ends of the sleeve by heat shrinking the ends of the sleeve to the tightly wound coils immediately adjacent the int~rr~ iate window section.
A small gap exists between the coils of the intermediate window section and the sleeve such that the contour of the coils in the window section do not project through the sleeve. Thus, the guidewire provides a distal region having highly radiopaque distal and proximal portions and a lightly radiopaque intermediate- portion (except for the darker radiopaque markers ) .
The guidewire of the invention is int~n~lPd to be used such that the ~on-radiopas;ue section ( if using the guidewire of the first or second ~mhsrlim~nts), or lightly radiopaque section ( if using the guidewire of the third or fourth ~mhcu1i tc), is placed within the stenosed region of the SU8S1 1TUTE SHEET (RULE 26~

WO9~12.1237 ~ i- 2 ~ 84484 PCT~TS95103076 artery so that the radiopacity of the guidewire will not interfere with the fluoroscopic imaging of the stenosis when the artery is injected with radiopaque contrast liquid. The radiopaque markers provide a reference for the physician to measure the length of the stenosis, the dimensions of the adjacent arterial area, and/or to mark the location of a lesion or a stent. Thus, the markers aid in the selection of an appropriate balloon and, if necessary, in the selection of an appropriate stent. This invention allows the physician to do this regardless of visualization angle or degree of fluoroscopic magnification. The polymer sleeve insulates the spaced coils or bands from the inner arterial wall and provides a uniform outer diameter (in some embodiments) to the distal region of the guidewire such that a catheter will smoothly move over the guidewire.
DEST-RIPTION OF THE DRAWI~iTGS
The foregoing and other objects and advantages of the invention will be appreciated more fully from the following further description thereof, with reference to the ~-c ~ ying drawings wherein:
FIG. 1 is a longitudinal sectional frT~J ~od illustration of f irst embodiment of the invention;
FI~. 2 is a longitudinal sectional fra~ d illustration of a second embodiment of the invention;~
FIG. 3 is a longitudinal sectional fragmented illustration of a third embodiment of the invention;
FIG. 4 is a longitudinal sectional fragmented illustration of a variation to the third em~odiment of the invent ion: and SUBSTIME SHEET (RUL~

j ~ 2 1 84484 so410/7227WO

FIG. 5 is a longitudinal sectional fragmented illustration of a fourth embodiment of the invention.
It is to be appreciated that the figures are not drawn to scale and are highly diagrammatic to illustrate the concepts of the invention.
DT'C~RTPTION OF T~T~ TT,T,USTR;~TIVE F~ lF3ODTl~FiNT
FIG. 1 shows a first embodiment of the invention. As shown, the guidewire, when ;nt~n~Pd for percutaneous transluminal coronary angioplasty may be approximately 175 cm to 300 cm in total length and_includes an elongated rotationally rigid, longitudinally flexible core wire 10, preferably made of stainle3s steel or other material suitable for use as a guidewire shaft. The majority of the length ~approximately 148 cm to 273 cm) is in the proximal segment ll of the core wire which ha~ a substantially uniform diameter of approximately 0 . 25 to 0 . 457 mm (0.010 to 0.018 inches). The proximal segment 11 merges into a first tapered segment 12, about 3 cm long which, in turn, merges into an intermediate barrel segment 14, approximately 22 . 5 cm long and about 6 mils in diameter. Intermediate segment 14 merges into a second tapered segment 15, about 3 cm long which, in turn, merges into a distal barrel segment 16, about 2.5 cm long and approximately . 05 mm (2 mils) in diameter. The distal segment 16 is more f lexible than the intermediate segment 14 .
Alternatively, the core wire (from taper 12 to distal segment 16) may have a continuous taper along its length.
AMENDED SHEEr I PEA/EP

~ 2 ~ ~4484 so410/7227Wo A distal coil 18, approximately 3 cm in length, is supported about the distal segment of the core wire and preferably is attached at its proximal end to the core wire by adhesive at joint 20. Suitable adhesives include an ultraviolet curable adhesive or a cyanoacrylate adhesive. The joint 20 alternatively may be welded, soldered or brazed. The distal coil 18 is attached at its distal end to the core wire by a distal hemispherical tip weld 22. The distal coil may be formed from a highly radiopaque material such as a gold/platinum or platinum/tungsten alloy. In a guidewire intended for use in percutaneous transluminal coronary angioplasty, the diameter of the wire from which the distal coil 18 is wound preferably is within the range of 0 . 025-0 .102mm ( . 001- . 004 inches) . The outer diameter of the distal coil 18 preferably is within the range of 0.25 - 0.46 mm (.010-.018 inches).
A proximal coil 24 is 3upported about the intermediate segment 14 of the core wire and is preferably attached at its distal end to the core wire by adhesive at joint 26. The proximal end of coil 24 extend3 to the proximal end of the intermediate segment 14 of the core wire where it may be attached to the core wire by adhesive at joint 25. Joints 25 and 26 may alternatively be welded, soldered or brazed. The outer diameter of the proximal coil is preferably the same as that of the distal coil 18. The proximal coil preferably is 7-22 cm in length. The proximal coil 24 may be less radiopaque than the distal coil 18 or of equivalent radiopacity. The proximal coil preferably is formed from the same material a~ the distal coil but may be formed from smaller diameter wire to achieve the desired reduced radiopacity . AMENDED SHEFT
IPtAlEP

21 844~4 B0410t7227WO
g The region of the guidewire between the proximal and distal coils, inr]ll~;nJ a portion of the int~ te segment 14 and tapered segment 15, is covered by a f lexible polymeric sleeve 34 .
The sleeve, preferably having an outer diameter er~ual to that of the proximal and distal coils, provides a uniform outer ,1; i tPr to the distal region of the guidewire such that the catheter will -smoothly move over the guidewire during advi~nrpm~nt~ The sleeve preferably is flexible, kink resistant and includes a lubricious surface for aiding in guidewire maneuverability. The sleeve preferably is formed from a polymer material (such as polyamide or polyethrlene) which exhibits the above properties. A
hydrophilic or hydrophobic coating may be used to coat the outer surface of the polymer sleeve for added lubricity.
The sleeve preferably is as thin as is practical, depending on the polymer material from which the 81eeve iiY made, in order that the region of the sleeve displays a desired degree of flexibility. The wall thickness of the sleeve preferably falls within the range of 0.005 - 0.05 mm (.0002-.002 inches). The sleeve preferably covers the proximal end of the distal coil and the distal end of the proximal coil and may be 5-20 cm in length.
As shown in FIG. 1, the distal end of the proximal coil 24 and the proximal end of the distal coil 18 can be stretched and tapered down to a smaller diameter in the region where they are attached to the core wire and overlapped by the ends of the polymer sleeve 34. The polymer sleeve preferably is adhesively attached at both ends to the guidewire. If adhesively attached, a small gap 23 exists between the inner surface of the sleeve and outer surfaces of AMENDE~ SHEET
IPEA/EP
. _ , . , .. , .. , . . , _ . . .. .. .

2~8~484 so410/722~Wo /

the marker bands 28, 30 and 32 (discu3sed below). The size of the gap is approximately equal to 0 . 025mm ( . 001 inches) but would depend on the rh;~kn~qs of the sleeve wall and the outer diameter of the marker bands. The gap prevents the outer contour of the marker bands from projecting through the polymer sleeve.
Alternatively, the sleeve may be heat shrunk about the guidewire.
Radiopaque marker bands 28, 30 and 32 are attached to the core wire between the proximal and distal coils. Marker bands 28, 30 and 32 preferably are attached by adhesive at joints 36, 38 and 40, respectively. Alternatively, ;oints 36, 38 and 40 may be welded or brazed. The marker bands preferably are made from a radiopaque material such as tantalum, platinum, gold or alloys thereof. The marker bands will be spaced to provide optimum usability for various l n vivo dlmension measurements by a physician. Particularly, the spacing and dimensions of the marker bands provide ref erence lengths such that the length and shape of a lesion and adjacent arterial dimensions can be determined fluoroscopically. Such a determination can aid a physician in the selection of an appropriately sized balloon.
Additionally, if necessary, such a determilzation aids in the selection of an appropriately sized stent The marker bands also provide reference locations which can aid in placing a post-stent balloon after stent placement. While the guidewire preferably includes three marker bands, as shown and described, it is envisioned that as few as one marker band could be used.
AMENDE~D SHEET
IPEAIEP

WO 95/2.1237 ~ t ~ PCTrUSs~rO3076 ' The guidewire of the first embodiment thus has a distal tip section 16 that is highly radiopaque, an ;nt~rr^C~iate section (between the coils) that is non-radiopaque (except for the marker bands), and a proximal section that is moderately or highly radiopaque. Such an arrangement may be referred to as "grey/white/black" or "black/white/black"
~from the proximal to the distal ends), referring to its relative appearance under fluoroscopy. The highly radiopaque distal segment provides clear, Yisible, fluoroscopic indication of the distal tip of the guidewire to indicate clearly the guidewire position. Typically, the distal tip of the guidewire is advanced through and beyond the stenosis to be treated. The jn' -';ate, non--radiopague segment is intf~n~led to be disposed at the region of the stenosis so that the region will be ~ulob~L.Lcted by radiopague effects of the guidewire. Thus, the full radiopaque effect of the radiopa~ue contrast liquid injected into the artery can be visualized on the fluoroscope, particularly in the critical stenosed region of the artery. The moderately or highly radiopaque proximal segment provides an indication of the position and conf iguration of the more proximally located portions of the guidewire and, therefore, the proximal arterial anatomy.
The "grey/white/black" or "black/white/black"
configuration can be achieved with the appropriate relative degrees of radiopacity by varying the thicknesses of the wires from which the coils are wound, as described above.
Alternatively, as will be understood by those skilled in the art, the coils may be plated with varying thicknesses of radiopaque material to achieve the desired levels of SU~SrIME SHEET (RULE 26) wo ssl2~237 2 ~ 8 4 4 8 4 PCT/US9S/03076 , ~ " r t --12-- ~
radiopacity. The plating process is described in U . S . Patent No. 5,144,959 (Gambale), which is herein incorporated by reference in its entirety.
FIG. 2 illustrates a second embodiment of the invention which is fairly similar in construction to the first i . Like elements in FIG. 2 are referred to by identical reference characters ~to those in EIG. 1). In the embodiment of FIG. 2, the construction of the core wire 10, the distal coil 18, and the marker bands 28, 30 and 32 is identical to that of the first ' ~i L ~shown in FIG. 1).
The guidewire of the second embodiment, however, omits the proximal coil 24 of the first ~ . As in the first : ~o~; ~, a polymeric sleeve 34, having the same properties as those described above, encases the proximal end of the distal coil and the marker bands. In the second ' ~
however, sleeve 34 extends proximally of the marker bands to tapered segment 12 of core wire 10. The sleeve provides a uniform outer diameter to the distal region of the guidewire to aid in smooth advdllcG t of the catheter over the guidewire. The sleeve preferably is adhesively attached at both ends to the guidewire. Like the: ' of FIG. 1, if adhesively attached, a small gap 39 exists between the inner surface of the sleeve and the outer surface of the marker bands 28, 30 and 32. The gap prevents the outer contour of the marker bands from projecting through the polymer sleeve. Alternatively, the sleeve may be heat shrunk about the guidewire such that, proximally of the marker bands, the sleeve 34 tapers down to f it tightly around the int~r--~l; Ate segment 14 of core wire to create a smooth transition .
SU35r1TUTE SHEET (RULE 26) so410,/7227wo !

The guidewire of the second embodiment thus has a distal region including a distal tip section 16 that i8 highly radiopaque and a proximal section that is non-radiopaque. Such an arrangement is referred to as "white/black" (from the proximal to the distal ends), referring to its relative appearance under f luoroscopy As with the embodiment of FIG . 1, the highly radiopaque distal segment provides clear, visible fluoroscopic indication of the distal tip of the guidewire to indicate clearly the guidewire position and the proximal, non-radiopaque segment provides for unobstructed visualization of the stenosis.
FIG. 3 shows a third embodiment of the invention in which a radiopaque coil 50 is supported by and attached to a distal region of the core wire 51 Core wire 51 is an alternate embodiment core wire in which the distal barrel segment 16 of the core wire 10 of the first embodiment is absent and is replaced by a pair of round forming wires 53 and 55 which extend from tapered segment 15 to hemispherical tip weld 22 The forming wires, typically 3-7 cm in length, preferably are adhesively attached to tapered segment 15 and extend approximately 2 cm beyond the distal tip of core wire 51 ~he forming wires preferably are formed from materials such as stainless steel, Sandvik lRK91, PH455 or MP35~ Coil 50 can be used, however, with the core wire 10 of the first embodiment. Similarly, the guidewire constructions of the first and second embodiments can be used with the core wire 51 AMENDED SHEET
IPEA/EP

2 1 8~484 As shown in FIG. 3, the distal end of the coil 50 is attached to the hemispherical tip weld and the coil extends proximally to the tapered section 12 of the core wire. The proximal end of the coil 50 is attached to the core wire by adhesive at joint 52.
Alternatively, joint 52 may be soldered or brazed. Coil 50 may also be attached to the core wire, preferably by adhesive, near the distal end of the coil to add structural integrity to the distal end of the guidewire such that unwinding of the coil during adv~n~ ~mf~n~ of the guidewire through an artery i~
prevented. Spring 50 preferably is formed from a radiopaque material such as a platinum/gold or other suitable alloy. The diameter of the wire from which the coil 50 is wound preferably is within the range of 0.025 - p.10 mm (0.001-0.004 inches). The outer diameter of the coi1 preferably is within the range of o . 25 - 0.46 mm (.010-.018 inches). A typical coil length falls within the range of 5-20 cm. If using a coil having a length of 5 cm, the corresponding dimensions of the core wire would be less than that disclosed above, as will be appreciated by those skilled in the art.
Spring 50 has varying pitch along its length including multiple tightly wound coil sections separated by loosely wound coil sections. The tightly wound coil ~iections appear dark under fluoroscopy and the loosely wound coil sections appear light.
Among the tightly wound coil sections are a distal section 54, preferably within the range of 2-3 cm in length, and a proximal section 55, within the range of 3-10 cm in length. Thus, the proximal and distal sections are highly radiopaque.
AMENDED SHEET
~PEA/EP

wo 9sl2~237 , ~ PCTlUSsSI03076 ~ 2 1 ~4484 An intermediate section 57 of the coil may include multiple tightly wound coil sections 56; 58, 60, 62, and 64, and loosely wound coil sections 65, 66, 68, 70, 72, and 7~.
The iLlL ~-'i ate section as a whole appears light under fluoroscopy with the tightly wound sections appearing as dark markers, providing reference lengths and location markers for the physician. Markers 56, 58, 60 and 62 may be uniformly spaced, preferably in 1 cm to 2 cm multiples. The number of markers and the length and spacing thereof, however, can be changed to suit a particular application. It is envisioned, that as few as one marker band could be used.
The majority of the length of the spring, from a proximal point of the distal section to the proximal end of the spring, is covered by a f lexible polymeric sleeve 34 . Sleeve 34 exhibits the same ~ualities as the sleeve described above in connection with the f irst and second embodiments . The sleeve provides a uniform outer diameter to the distal region of the guidewire. The sleeve, therefore, helps to ensure smooth catheter ~ over the guidewire during advAn,~- L. Sleeve 34 preferably is adhesively attached to the guidewire at proximal 76 and distal 78 joints. If adhesively attached, a small gap 80 exists between the outer surface of spring 50 and the inner surface of sleeve 34. The gap enables free bending ~l ,t of the coils of spring 50 beneath the sleeve 34 while the guidewire is maneuvered through an artery. Additionally, the gap ~ v~ S the co~tour of the outer surface of the coils from projecting through the polymer sleeve 34. Alternatively, the ends of the sleeve 34 maybe heat shrunk about the guidewire. It should be unde~stood that the m-thod of attaching the sleeve to the SuaST~ME SHEET (RULE 26) ~,~'0 95121237 2 1 8 4 ~ 8 4 PCTIUS95/03076 3 1, guidewire only at its ends by adhesive or by heat shrirking its ends can be used with any of the guidewire embodiments disclosed herei~.
The guidewire of the third o-`~oAi ~ thus has a distal tip section and a proximal section that are highly radiopaque and an int: -~iate section that is lightly radiopaque (except for the darker markers). Such an arrangement is referred to as "black/grey/black" (from the proximal to the distal ends), referring to its relative appearance under fluoroscopy. As with the previously described ~ ts, the highly radiopaque distal segment provides clear, visible fluoroscopic indication of the distal tip of the guidewire to indicate clearly the guidewire position and the int e~ii ate, lightly radiopague segment provides for substantially unobstructed vis~ a~; on of the stenosis .
As described above, the proximal and distal sections of the coil preferably are equally highly radiopaque.
Alternatively, the distal section can be more radiopaque than the proximal section. To achieve the desired relative radiopacity, the distal section 54 of the coil may be wound from a wire having a greater diameter than that of the proximal sectio~. Alternatively, as will be understood by those skilled in the art, the distal section 54 may include another shorter radiopaque coil 90 which is supported by and attached to the extreme distal part of the core wire and which is located within the distal section of the coil, as shown in FIG. 4.
Referring to FIG. 4, inner coil 90 is attached at its distal end to the hemispherical tip weld 22 and may be attached at its proximal end to the forming wires 53 and 55 SUBSTITUTE SHEET (RULE 26) . O - 2i8'1~84 and the tapered segment 15, preferably by adhesive.
Alternatively, the proximal end of the inner coil may not be attached to any element. Be~ides inner coil 9o, the embodiment of FIG. 4 is identical to that of FIG. 3. The inner coil 90 preferably has an outer diameter within the range of 0.15 - 0.30 mm(.006-.012 inches~, a length within the range of 1-4 cm, and is made from a radiopaque material such as platinum, gold or a platinum/gold alloy. The diameter of the wire from which the inner coil is wound i5 preferably within the range of 0 . 025 -0 . 076 mm ( . 001 to 003 inches) . The inner coil 90 is surrounded by the distal section of the coil 50 such that the distal ~ection will appear highly radiopaque.
FIG. 5 shows a fourth embodiment of the invention in which the guidewire preferably falls within the range of 180-300 cm in length and includes an elongated rotationally rigid, longitudinally flexible core wire 10, preferably made of stainle~s ~teel. The majority of the length (preferably 110-280 cm) of the core wire is in the proximal portion 11 which has a substantially uniform diameter, typically within the range of 0.25 -~0.46 mm (10-18 mils) . The proximal portlon 11 merges into a first tapered segment 12, preferably 2-10 cm in length, which, in turn, merge~ into a first barrel segment 13, preferably 10-20 cm in length. The diameter of barrel segment 13 preferably is within the range of 0.13 - 0.30 mm (5-12 mils), less than that of proximal portion 11 First barrel segment 13 merges into a second tapered segment 17, preferably 2-6 cm in length, which, in turn, merges into a second barrel segment 19, preferably 5-15 cm in length. The diameter of barrel segment 19 preferably is within the range of 0.10 - 0.25 mm(4-10 mils), less than that of AMENDEI~ EET
IPEA~'EP

~ - 2 1 84484 f irst barrel segment 13 . Barrel segment 19 merges into a third tapered segment 21, preferably 2-10 cm in length, which extends to the distal end of the core wire.
One or more forming wires (only one of the forming wires 53 is shown) extend from tapered segment 21 to a rounded tip weld 22. The forming wires, typically one to five cm in length, preferably are adhesively attached to tapered segment 21 at joint 78 and extend approximately 2 cm beyond the distal tip of core wire 10. Alternatively, joint 78 can be soldered or brazed. The forming wires preferably are made from a specially treated precipitation hardenable alloy material. One such material is an alloy of nickel, cobalt, molybdenum and chromium, colllmercially available from Fort Wayne Metals of Fort Wayne, Indiana under the trade designation MP35N. Another suitable material i8 a single stage martensitic precipitation hardenable stainless ~teel having modif ied proportions of chromium and nickel and with additional elements of copper and titanium, commercially available f rom Carpenter Steel Co. of Reading, Pennsylvania under the trade designation 455PH. Still another suitable material i~ a precipitation hardenable alloy that is commercially available from Sandvik Steel under the trade designation Sandvik lRKgl.
While the distal region 27 of the core wire has been shown and described herein as including two tapered segments, two barrel segments and two forming wires, it should be understood that other core wires can be used with this fourth embodiment such as, for example, a core wire that has a distal region including only a single barrel segment which merges into a tapered segment that extends to the distal end AMENDED SHEET
IPEA/EP

. ~ ` t~
- 2 ~ ~4484 sO410/7227WO

of the core wire (with or without forming wires). Any of the guidewire embodiments disclosed herein can be practiced with a core wire having a distal region that either includes one or more forming wires or, alternatively, a core wire that extends to the distal tip of the guidewire.
A radiopaque coil 50 is supported by and attached to the distal region 27 of the core wire 10. The distal end of the coil 50 is attached by the hemispherical tip weld. Just proximally of the distal end of coil 50, the coil is attached to the core wire at joint 78. Joint 78 also adds integrity to the structure of the distal end of the guidewire to prevent the coil 50 from separating from the core Mire if the forming wires break during use. The coil extends proximally to the tapered sectipn 12 o the core wire lO. The proximal end of the coil is attached to the corc wire by adhesive at joint 52. Alternatively, joint 52 can be soldered or brazed. Spring 50 preferably is formed from a radiopaque material such as platinum/gold or other suitable alloy. The diameter of the wire from which the coil is wound preferably is within the range of 0 . 038 - 0 . 076 mm ( . 0015 - . 003 inches). The outer diameter of the coil preferably is within the range of 0 . 25 - 0 . 45 mm ( . 010 - . 018 inches) . A typical coil length falls within the range of 15-40 cm. While the coil is shown in FIG. S as having an outer diameter that is less than that of the proximal portion 11 of the core wire, it is to be appreciated that the outer diameter of the coil is preferably equal to or approximately equal to the outer diameter of the proximal portion 11 of the core wire.
Al~AENDED SHEET
IPEA/EP

wo g~/2~237 PCr~'S9~/03076 t -~
~ 21 ~4484 Spring 50 has varying pitch along its length including distal and proximal tightly wound coil sections 54 and 55 separated by an intermediate loosely wound window coil section 57. The tightly wound coil sections appear dark under fluoroscopy and the loosely wound window coil section appears light. Distal section 54 preferably falls within the range of one to five cm in length, proximal section 55 preferably falls within the range o 10--25 cm in length, and -~iiate window section 57 preferably falls within the range of 5-20 cm in length.
Tntl -~iate window section 57 may include a number of short tightly wound coil sections (not shown) separated by loosely wound coil sections as in the embodiment of FIG. 3.
The tightly wound sections appear as dark marlcers under fluoroscopy for providing reference lengths and location marks for a physician. The number of markers and the length and spacing thereof can be selected to suit a particular application .
T L ~iate window section 57 of the coil 50 is covered by a flexible polymeric sleeve 81. The sleeve 81 is kink resistant and includes a lubricious surface for aiding in guidewire maneuverability. The sleeve preferably is formed from polyethylene terephthalate (PET) but may be formed from other thermoplastic polymers such as polyethelene. A
hydrophilic or hydrophobic coating may be used to coat the outer surface of the guidewire including the polymer sleeve for added lubricity.
The sleeve preferably is as thin as is practical, depending on the polymer material from which the sleeve is made, in order that the region of the sleeve displays a SUBSTITUTE SHEET (RUI.E 26~

~ - - 2 ~ 84~4 so410/7227Wo desired degree of flexibility. The wall thickness of the sleeve preferably falls within the range of 0.005 - 0.05 mm (.0002-.002 inches). The sleeve 81 is attached to the guidewire only at its proximal and distal ends 82 and 84 leach preferably within the range oi 0.5-2 cm in length) by heat shrinking the sleeve only at those ends. Only the ends 82 and 84 of the sleeve 81 are respectively heat shrunk about the tightly wound coils of the proximal 55 and distal 54 regions immediately adjacent the window section 57.
A small gap 80 exists between the outer surface of the intermediate section 57 of coil 50 and the inner surface of sleeve 81. The size of the gap is approximately equal to . 0001 inches but would depend on the thickness of the sleeve wall and the outer diameter of the spring. The gap prevents the contour of the outer surface of the coils from projecting through the sleeve and contacting the inner arterial wall (which would occur if the sleeve were heat shrunk about the entire length of the coil) so that the guidewire can be navigated smoothly through the artery during use. Additionally, the sleeve 81 insulates the loosely wound coils of the intermediate section 57 from the inner arterial wall to prevent them from significant m.,v t relative to one another during advancement through an artery. Such movement could result in altering the fluoroscopic image of the guidewire and/or altering the structure and functionality of the coils of the spring.
The distal region of the fourth embodiment (FIG 5) of the guidewire thus has distal tip and proximal sections that are highly radiopaque and an intermediate section that is lightly radiopaque- Such an Alr\~Eln~Dem-eDn~ EErTeferred to as IPEA/EP

wo 9512 1237 ~ PCTIUS95103076 ' `i 21~4484 "black/grey/black" (from the proximal section to the distal end), referring to its relative appearance under fluoroscopy. The highly radiopaque distal segment provides clear, visible fluoroscopic indication of the distal tip of the guidewire to indicate clearly the guidewire position, Typically, the distal tip of the guidewire is advanced through and beyond the stenosis to be treated. The ;ate, lightly radiopaque segment is inr~n~ tl to be disposed at the region of the stenosis so that the region will not be materially obstructed by radiopaque effects of the guidewire. Thus, the full radiopaque effect of the radiopaque contrast liquid injected into the artery can be visuali~ed on the fluoroscope, particularly in the critical stenosed region of the artery. The radiopaque proximal segment provides an irldication of the position and configuration of the more proximally located portions of the guidewire and, therefore, the proximal arterial anatomy, so that a physician can observe the more proximally located portions of the guidewire.
The proximal and distal sections of the coil preferably are equally highly radiopaque. Alternatively, the distal section can be more radiopaque than the proximal section. To achieve the desired relative radiopacity, the distal section 54 of the coil may be plated with a radiopaque material.
The guidewire of the present inventio~ provides a number of advantages. The guidewire facilitates better lesi~n asse~ both by providing a non-obstructing region that does not impair fluoroscopic evaluation of the shape of the lesion and by providing a radiopaque proximal section that allows visualization of the proximal portion of the wire. It SUBSrlTUTE SHEET (RULE 26) wo g~/2~237 ~ ;, PCT/US~/03076 ; ~ 2 1 ~ 4 4 8 4 ' also provides radiopaque markers which offer a simple means by which the physician can determine the length of the lesion, adjacent arterial dimensions, and/or reference lesion or stent location. Selection of an appropriately sized balloon and, i necessary, selection of an appropriate stent is, therefore, facilitated. Additionally, the sleeve provides a uniform outer diameter to the distal region of the guidewire to ensure smooth r,l~ v~ t of the catheter during advancement. Also, as in the fourth embodiment, by heat shrinking the sleeve only at its ends, the outer contour of the coils is prevented from projecting through the sleeve, and the sleeve insulates the loosely wound coils from the inner arterial wall, preventing them from substantial relative r ~ L.
Thus, we have described a guidewire having varied degrees of radiopacity whereby, a distal section of the distal region of the guidewire appears dark under fluoroscopy and an jnt~ -aiate section o~ the distal region appears generally white (or light in an alternate: ' -'; t). At least one radiopaque marker may be located in the int, 'iate section for providing rèference lengths and location marks for a physician. A polymer sleeve encases at least part of the distal region, providing a uniform outer diameter to the region (in some: ' li tS), to aid in smooth catheter advAn. ~. It should be understood, however, that the foregoing description of the invention is ;nt~n~ ad merely to be illustrative thereof and that other embo~ai and modifications may be apparent to those skilled in the art without departing from its objects, purposes and spirit.
Having thus described the invention, what we desire to claim is:
SUBSrlTUTE SHt~T (RULE 26)

Claims

-24 -

1. A medical guidewire having an elongate flexible shaft (10); a distal radiopaque coil (18) supported about and attached to a distal portion of the shaft (15); a proximal radiopaque coil (24) supported about and attached to an intermediate portion (14) of the shaft, the proximal coil being spaced from the distal coil; a polymer sleeve (34) encasing the shaft between the proximal and distal coils and at least a portion of the proximal and distal coils characterized by at least one radiopaque marker (28, 30, 32) attached to the shaft between the distal and proximal coils, the at least one marker being encased by the polymer sleeve and the space between the coils being less radiopaque than the coils and the at least one marker.

2. A medical guidewire as defined in claim 1, further characterized in that the polymer sleeve (34) encases a proximal region of the distal coil and a distal region of the proximal coil (24).

3. A medical guidewire as set forth in claim 1 further characterized by the at least one radiopaque marker (28, 30, 32) being attached to the shaft (14).

4. A medical guidewire as set forth in claim 1 further characterized by the at least one marker (28, 30, 32) including at least one radiopaque marker band attached to the shaft (14).

5. A medical guidewire as set forth in claim 1 further characterized in that the distal coil (18) is more radiopaque than the proximal coil (24) such that the distal coil will appear darker than the proximal coil under fluoroscopy.

6. A medical guidewire as set forth in claim 5 further characterized in that the wire from which the distal coil (18) is wound has a greater diameter than the wire from which the proximal coil (24) is wound.

7. A medical guidewire as set forth in claim 1 further characterized in that the radiopacity of the distal coil (18) is approximately equal to the radiopacity of the proximal coil (24) such that both coils will appear equally dark under fluoroscopy.

8. A medical guidewire having an elongate flexible shaft (10); a radiopaque coil (18) supported by and attached to a distal portion of the shaft (15) further characterized by at least one radiopaque marker (28, 30 ,32) attached to an intermediate portion of the shaft (14), proximally to the coil (18); and a polymer sleeve (34) attached to the shaft and encasing the at least one marker such that a gap (39) exists between the at least one marker and the sleeve.

9. A medical guidewire as set forth in claim 8 further characterized by the at least one marker (28, 30 ,32) including at least one marker band (28, 30 ,32) attached to the shaft (14).

10. A medical guidewire as set forth in claim 9 further characterized by the polymer sleeve also encasing the shaft (14) proximally to the at least one marker band (28, 30 ,32).

11. A medical guidewire as set forth in claim 10 further characterized by the polymer sleeve (24) also encasing the proximal end of the coil (18).

12. A medical guidewire comprising an elongate flexible shaft (10) and a first radiopaque coil (50) supported by and attached to a distal region of the shaft (10) further characterized by the first coil having highly radiopaque distal and proximal sections (54, 55) and more moderately radiopaque intermediate section (57), the intermediate section of the first coil including at least one tightly wound coil section (64) separated from the distal and proximal sections by loosely wound coil sections (74); and a polymer sleeve (34) attached to the shaft (12) and encasing the first coil along a majority of the length of the coil such that a gap (80) exists between the sleeve and the coil.

13. A medical guidewire as set forth in claim 11 further characterized by a second radiopaque coil 90 supported by the distal region of the shaft (15), wherein the distal section of the first coil (54) surrounds the second coil (90).

14. A medical guidewire having an elongated, flexible shaft (10) having a proximal region and a distal region; a helical coil (50) mounted to and disposed about the distal region of the shaft and at least a segment (74) of the helical coil being loosely wound further characterized by a flexible polymeric sleeve (34) covering at least that segment of the coil that is loosely wound;
the sleeve being attached to the guidewire both proximally and distally of the loosely wound coil segment, the sleeve being dimensioned with respect to the coil to define an annular gap (80) between an outer surface of the coil and an inner surface of the sleeve.

15. A medical guidewire as defined in claim 14 further characterized by the regions of the sleeve (34) that are attached to the guidewire being attached adhesively.

16. A medical guidewire as defined in claim 14 further characterized by the ends of the sleeve (34) being heat shrunk about the guidewire.

17. A medical guidewire as defined in any one of claims 14-16 further characterized by at least one radiopaque marker (62) defined along the loosely wound segment of the coil.

18. A medical guidewire having an elongated, flexible shaft (10) having a proximal region and a distal region, a helical coil (50) mounted to and disposed about the distal region of the shaft and at least a segment (57) of the helical coil being loosely wound further characterized by a flexible polymeric sleeve (81) covering at least that segment of the coil that is loosely wound;
the sleeve being attached to the guidewire only at its ends (82, 84) both proximally and distally of the loosely wound coil segment.

19. A medical guidewire as defined in claim 18 further characterized by the helical coil (50) including tightly wound proximal (55) and distal (54) coil sections and wherein the sleeve (81) is attached only to a distal end of the proximal tightly wound coil section and a proximal end of the distal tightly wound coil section.

20. A medical guidewire as defined in either of claims 18 or 19 further characterized by the sleeve (81) being heat shrinkable and the sleeve is heat shrunk only at its ends (82, 84) to the guidewire.

21. A medical guidewire having an elongated, flexible shaft (10) having a proximal region and a distal region, a helical coil (50) mounted to and disposed about the distal region of the shaft and at least a segment (57) of the helical coil being loosely wound; further characterized by a flexible polymeric sleeve (81) covering at least that segment of the coil that is loosely wound, the sleeve being loosely disposed about the loosely wound segment of the coil, the sleeve being attached only at its end (82, 84) to the guidewire.

22. A medical guidewire as set forth in claim 1 further characterized by the at least one marker being a plurality of markers (28, 30, 32) having predetermined spacing.

23. A medical guidewire as set forth in claim 1 further characterized by the at least one marker being a plurality of markers (28, 30, 32) having equal spacing.