WO1992007610A1

WO1992007610A1 - Catheter exchange apparatus with removable inflation assembly

Info

Publication number: WO1992007610A1
Application number: PCT/US1991/007926
Authority: WO
Inventors: William H. Penny; Stephen R. Paidosh; Larry E. Fuller
Original assignee: Scimed Life Systems, Inc.
Priority date: 1990-10-24
Filing date: 1991-10-24
Publication date: 1992-05-14

Abstract

A catheter exchange apparatus (10) for exchanging a first non-over-the-wire catheter for a second non-over-the-wire catheter without reestablishing the path through a patient's vascular system to stenosis includes a coupler (12). The coupler has a luer fitting that allows the coupler to be releasibly secured to an inflation assembly. A sliding member (64) slidably mounted on the coupler is movable between a first state wherein a hypotube (28) of a catheter (14) is freely receivable within a through slot (50) of the coupler, and a second state wherein the hypotube is firmly gripped between an engagement surface of the sliding member and a bottom wall (58) of the through slot. The hypotube of the catheter can be affirmatively and releasibly coupled to an extension wire (128) once the hypotube is disengaged from the coupler and inflation assembly combination. The extension wire (128) is joined to the hypotube by way of a snap-fit connector (126) which increases the length of the catheter for catheter exchange purposes. A pathway tube (158) can be slid over the catheter and extension wire combination such that a distal end of the pathway tube crosses the stenosis.

Description

-1-

CATHETER EXCHANGE APPARATUS WITH REMOVABLE INFLATION ASSEMBLY BACKGROUND OF THE INVENTION The present invention relates to the field of percutaneous translu inal coronary angioplasty (PTCA) . In particular, the present invention is an exchange apparatus that permits the exchange of a first non-over- the-wire dilatation catheter, within a patient's vascular system, for a second non-over-the-wire dilatation catheter to be accomplished without reestablishing the path through the patient's vascular system to the stenosis.

Angioplasty has gained wide acceptance in recent years as an efficient and effective method for treating types of vascular diseases. In particular, angioplasty is widely used for opening stenosis in the coronary arteries, although it is also used in the treatment of stenosis in other parts of the vascular system. The most widely used form of angioplasty makes use of a dilatation catheter which has an inflatable balloon at its distal end. Using fluoroscopy, the physician guides the catheter through the vascular system of a patient until the balloon is positioned across the stenosis. The balloon is then inflated by supplying a fluid under pressure through an inflation lumen in the balloon. The inflation of the balloon causes stretching of the artery and pressing of the lesion into the artery wall to reestablish acceptable blood flow through the artery.

Over-the-wire catheters and non-over-the-wire catheters are two types of dilatation catheters that are comirtonly used in angioplasty. An over-the- ire catheter has an inflation lumen and a guide wire lumen through which a guide wire is advanced to establish a path to the stenosis. The separate dilatation catheter is then advanced over the guide wire until the balloon is positioned across the stenosis.

A non-over-the-wire catheter does not require a separate guide wire, and thus does not have a guide wire lumen. The shaft of a non-over-the-wire catheter is sufficiently pushable that the catheter can be steered and advanced without a guide wire. Due to the fact that a non-over-the-wire catheter has no through lumen diameter to restrict balloon wrapping, such a catheter generally has the advantage of having a smaller profile than over-the-wire catheters, thereby allowing the non-over-the-wire catheter to traverse smaller stenoses than over-the-wire catheters.

Sometimes during the installation of a dilatation catheter, the balloon profile of the dilatation catheter is too large to cross the stenosis or the balloon inflated diameter so small that the balloon cannot effectively dilatate the stenosis. In other cases, the dilatation catheter may lack control or flexibility necessary to track a path to the stenosis. In either situation, the catheter must be exchanged for one with a different size balloon or for one with different tracking characteristics to alleviate the respective difficulty.

To exchange an over-the-wire catheter, the guide wire must first be replaced by one 300 cm long or the normal 175 cm guide wire extended to 300 cm by adding an extension wire to the proximal end outside of -3 -

the patient's body. A typical over-the-wire dilatation catheter is 135 cm long. The dilatation catheter is removed from the guide wire by holding the extended guide wire in place while pulling back on the catheter until the catheter is out of the patient's body. By similar means, a different catheter is placed on the extended guide wire and advanced to the stenosis. The guide wire remains in position within the vascular system during the exchange of catheters such that the path to the stenosis need not be reestablished. Not having to recross the lesion with a guide wire is considered safer in the that risk of entering a false lumen is reduced.

In comparison, to exchange a non-over-the-wire catheter, the catheter within the patient's vascular system is removed and a different catheter is inserted in its place. This exchange of catheters necessarily requires removal of the distal portion of the catheter from the stenosis due to the "single unit" construction of the non-over-the-wire catheter. Thus, to advance the replacement non-over-the-wire catheter to the stenosis, the entire pathway through the vascular system of the patient must be reestablished since no portion of the original catheter remains within the vascular system during the exchange. Establishing a path through the arterial tree to a stenosis is a difficult procedure and the risk of entering false lumen is great. Thus, having to accomplish this task more than once is highly undesirable. What is needed is a device that permits the exchange of a first non-over-the-wire catheter for a second non-over-the-wire catheter to be accomplished -4-

without reestablishing the pathway through the patient's vascular system to the stenosis. This device would reduce the risk of entering a false lumen and thereby make the angioplasty procedure less difficult. SUMMARY OF THE INVENTION

The present invention is a catheter exchange apparatus that permits a first non-over-the-wire catheter to be exchanged for a second non-over-the-wire catheter without reestablishing the path through a patient's vascular system. The exchange apparatus includes a coupler having a through slot extending from its proximal end to its distal end. The through slot is configured to receive a tubular proximal portion of a non-over-the-wire catheter which is adapted to have a distal portion thereof inserted into a patient's vascular system. A planar bottom wall of the through slot defines a first generally planar engagement surface.

The coupler further includes a sliding member having a second generally planar engagement surface that is aligned parallel to the bottom wall of the through slot. The sliding member is movable between a first state wherein the second engagement surface is spaced from the bottom wall such that the tubular proximal portion of the catheter can be readily inserted into the through slot; and a second state wherein the tubular proximal portion is securely gripped between the second engagement surface and the bottom wall of the through slot. Side walls of the through slot include a first pair of ramped surfaces that are configured to be engaged by a second pair of ramped surfaces formed on the sliding member. The first and second ramped -5-

surfaces cooperate to allow the sliding member to be slid between the first and second states.

The proximal portion of the coupler includes a luer fitting having a threaded portion that is adapted to cooperate with a threaded distal end of an inflation assembly. The luer fitting allows the inflation assembly to be readily attached to and detached from the coupler. The luer fitting further includes a through opening in aligned registry with the through slot. In addition, the through opening has an annular seal that engages an exterior portion of the tubular proximal portion of the catheter and forms a fluid-tight seal between the coupler and inflation assembly combination and the tubular proximal portion of the catheter. Positioned distally of the annular seal is a funnel member that forms a guide to direct the tubular proximal portion of the catheter into the through opening formed in the luer fitting. The funnel member includes a base portion having an opening in aligned registry with the through opening and an integral funnel portion extending partially into the proximal end of the coupler. The funnel portion is semi-cylindrical in shape and tapers radially outward from the opening in the base portion. The tubular proximal portion includes a collar the abuts the base portion of the funnel member to define a fully seated state of the catheter within the through slot of the coupler. The coupler allows the inflation assembly to be removed from the tubular proximal portion of the catheter. In addition, the coupler can be removed from the catheter by simply moving the sliding member from the second state back to the first state thereby freeing the tubular proximal -6-

portion.

The tubular proximal portion of the catheter can be joined to an extension wire. The extension wire includes a mating end defined by a tubular portion that forms a female connector member. The tubular portion includes a concentric groove that forms an inwardly extending concentric ridge. A mating end of the tubular proximal portion of the catheter defines a tubular segment that forms a male connector member that is received within the tubular portion of the extension wire. The tubular segment of the tubular proximal portion includes a concentric groove that forms a concentric channel. When the tubular segment is inserted into the tubular portion the concentric channel receives the concentric ridge in a snap-fit engagement manner. The tubular portion further may include a longitudinal slot that allows the tubular portion to expand radially outward as the tubular segment is inserted or removed from the tubular portion of the extension wire.

The extension wire includes a guide portion the is concentrically received within the tubular segment when the extension wire is coupled to the catheter. The guide portion acts as a guide and assists in initially aligning the tubular segment with the tubular portion during the coupling procedure. The guide portion may include a first bulb member. The first bulb member is configured to override in a snap- fit manner a concentric crest defined by the concentric groove of the tubular segment when the extension wire is coupled to the catheter.

The guide portion may further include a second -7-

bulb member spaced proximally from the first bulb member. The second bulb member is configured to abut the concentric crest when the extension wire is coupled to the catheter. To exchange a first non-over-the-wire catheter disposed within the vascular system of a patient for a second non-over-the-wire catheter the inflation assembly and coupler combination on the first catheter is removed by moving the sliding member from the second state to the first state which allows the tubular proximal portion of the first catheter to be removed from the coupler. This exposes the tubular segment of the tubular proximal portion of the first catheter. The tubular segment is inserted into the tubular portion of the extension wire to affirmatively secure the extension wire to the first catheter. This extends the length of the first catheter. A pathway tube is than inserted over the proximal end of the extension wire and is advanced distally over the extension wire and the first catheter until a distal end of the pathway tube extends through the stenosis adjacent to a balloon of the first catheter. The pathway tube is then held while the first catheter and extension wire combination is moved proximally away from the stenosis and out of the pathway tube.

Next, the extension wire is removed from the first catheter and snap locked onto the tubular proximal portion of the second non-over-the-wire catheter. While still holding the pathway tube, the second catheter is introduced into the pathway tube and moved through the vascular system of the patient with the pathway tube acting as a conduit. When the balloon of the second -8-

catheter reaches the stenosis, the second catheter and extension wire combination is held while the pathway tube is moved proximally away from the stenosis and out of the confines of patient's body. Next the extension wire is unsnapped from the second catheter and the tubular proximal portion of the second catheter is inserted into the coupler of the inflation assembly and coupler combination. The sliding member of the coupler is then moved from the first state to the second state wherein the tubular proximal portion of the second catheter is firmly gripped between the engagement surface of the sliding member and the bottom wall of the through slot of the coupler. The balloon of the second catheter is now ready to be inflated. In an alternative method of catheter exchange, the pathway tube is left in place in the vascular system of the patient during inflation of the balloon of the second catheter. In application, with the first catheter removed from the patient's body, the second catheter, with inflation assembly attached, is inserted into the pathway tube. The second catheter is then advanced distally through the pathway tube until the balloon of the second catheter is positioned so as to extend across the stenosis within the distal end of the pathway tube.

The pathway tube is then slid proximally along the second catheter (but is not removed from the second catheter) until the distal end of the pathway tube is no longer positioned within the stenosis. This procedure exposes the balloon of the second catheter that is in position across the stenosis. The balloon of the second catheter is then inflated to dilatate the stenosis. This catheter exchange apparatus is relatively uncomplicated and allows a first non-over-the-wire catheter to be exchanged for a second non-over-the-wire catheter without having to reestablish the pathway through the patient's vascular system. As such, this catheter exchange apparatus reduces the risk of the second catheter entering a false lumen and makes the procedure of inserting the catheter through the arterial tree a less difficult procedure. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of the catheter exchange apparatus in accordance with the present invention.

FIG. 2 is an enlarged side elevational view partially in section of a coupler of the catheter exchange apparatus shown in FIG. 1.

FIG. 3 is an enlarged exploded perspective view of the coupler shown in FIG. 2.

FIG. 4 is a sectional view of the coupler taken along line 4-4 in FIG. 2.

FIG. 5 is an enlarged elevational view of a snap-fit connector for releasibly coupling an extension wire to a non-over-the-wire catheter in accordance with the catheter exchange apparatus of the present invention.

FIG. 6 is a greatly enlarged elevational view partially in section of the snap-fit connector shown in FIG. 5.

FIG. 7 is an elevational view of the extension wire coupled to the catheter in accordance with the catheter exchange apparatus of the present invention. FIG. 8 is an elevational view similar to FIG. -10-

7 but with a pathway tube advanced over the extension wire and catheter combination in accordance with the catheter exchange apparatus of the present invention.

FIG. 9 is a greatly enlarged elevational view partially in section of the snap-fit connector illustrating an alternative embodiment of a guide portion of the extension wire.

FIG. 10 is a greatly enlarged elevational view partially in section of the guide portion of the extension wire shown in FIG. 9 illustrating an alternative embodiment of a bulb member.

FIG. 11 is a greatly enlarged elevational view partially in section of the snap-fit connector illustrating a further embodiment of a guide portion of the extension wire.

FIG. 12 is a greatly enlarged elevational view partially in section of the snap-fit connector illustrating a further embodiment of a guide portion and spacer of the extension wire. FIG. 13 is an elevational view of an alternative embodiment of the method of catheter exchange in accordance with the catheter exchange apparatus of the present invention.

FIG. 14 is an elevational view of a further alternative embodiment of the method of catheter exchange in accordance with the catheter exchange apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A catheter exchange apparatus 10 in accordance with the present invention is illustrated generally in

FIG. 1. The exchange apparatus 10 includes a coupler 12 for readily, releasibly securing a non-over-the-wire, -11-

dilatation balloon catheter 14 to an inflation assembly 16.

The catheter 14 is used to perform percutaneous transluminal coronary angioplasty (PTCA) 5 and is thereby adapted to have a distal portion 18 introduced into a patient's vascular system. The distal portion 18 of the catheter 14 includes an inflatable balloon 20 that is configured to be positioned within an arterial member of the vascular system across a stenosis 10 to be dilatated. A balloon waist portion 22 extends proximally from the balloon 20 and is coupled at a proximal end 24 to a distal end 26 of a tubular proximal portion, such as a stainless steel hypotube 28, of the catheter 14. A core wire extends from the hypotube 28 15 through the waist portion 22 and the balloon 20 and has a distal tip 30 to assist in steering the catheter 14 through the patient's vascular system to the stenosis.

As seen in FIG. l, the inflation assembly 16 includes an inflation device 32 having a catheter 0 connecting tube 34. A swivel luer-lock connector 36 is attached to a distal end 38 of the catheter connecting tube 34 and serves to connect the inflation device 32 to the coupler 12 and thereby the catheter 14. A three-way valve 40 may be optionally incorporated at the luer-lock 5 connector 36 to aid in eliminating air while priming the catheter 14. Inflation medium from the inflation device

32 enters the catheter 14 through the hypotube 28 and travels through the waist portion 22 to inflate the balloon 20 and thereby dilatate the stenosis. 0 As seen in FIGS. 2 and 3, the coupler 12 includes a generally cylindrical body member 48 having a longitudinal through slot 50 extending from a proximal -12-

end 52 to a frusto-conical shaped distal end 54. The body member 48 includes a plurality of longitudinally extending ribs 56 that add strength and rigidity to the coupler 12. The through slot 50 is defined by planar 5 bottom wall 58 that forms a first engagement surface and a pair of parallel upstanding side walls 60. The upstanding side walls 60 include a first pair of ramped surfaces, such as a pair of inwardly directed, sloped ledges 62 that extend from the proximal end 52 to just 0 proximally of the frusto-conical shaped distal end 54 of the body member 48. The inwardly directed, sloped ledges 62 extend at a four degree angle with respect to the planar bottom wall 58. The inwardly directed, sloped ledges 62 are configured to slidably support a 5 sliding member 64.

As seen best in FIG.3, the sliding member 64 has an overall I-beam shape as defined by an upper cross member 66, a lower cross member 68 and a central, upright longitudinal beam 70. A second pair of ramped 0 surfaces, such as a pair of oppositely directed, angled channels 72 are formed between the upper and lower cross members 66 and 68. The oppositely directed, angled channels 72 are configured to slide upon the inwardly directed, sloped ledges 62. The oppositely directed, 5 angled channels 72 extend parallel to the inwardly directed, sloped ledges 62 and thereby extend at a four degree angle relative to the planar bottom wall 58 of the through slot 50.

As seen best in FIG. 2, a bottom surface 74 of 0 the lower cross member 68 defines a second generally planar engagement surface 76 that is generally parallel to the planar bottom wall 58 of the through slot 50. With the inwardly directed, sloped ledges 62 received within the oppositely directed, angled channels 72, the sliding member 64 is movable relative to the body member 48 such that as the sliding member 64 is moved longitudinally (as represented by the directional arrow 78) from the proximal end 52 of the body member 48 to the distal end 54, the engagement surface 76 moves toward the planar bottom wall 58 of the through slot 50. The sliding member 64 is slidably movable from a first state wherein the sliding member 64 is positioned adjacent to the proximal end 52 of the body member 48 and the hypotube 28 is freely receivable into the through slot 50; and a second state (see FIG. 2) wherein the hypotube 28 of the catheter 14 is firmly gripped between the engagement surface 76 and the planar bottom wall 58. The sliding member 64 is held in the second state by frictional engagement between the oppositely directed, angled channels 72 and the inwardly directed, sloped ledges 62. The lower cross member 68 of the sliding member 64 includes ribs 80 that aid this frictional engagement.

The sliding member 64 is movable by a finger or thumb of an operator and the upper surface 82 of the upper cross member 66 includes lateral grooves 84 and a knob 86 to enhance the grip and facilitate the movement of the sliding member 64 between the first and second states. The hypotube 28 of the catheter 14 can be readily released from the coupler 12 by simply moving the sliding member 64 from the second state back to the first state. As seen in FIG. 3, the sliding member 64 includes angled front walls 88 that are configured to engage cooperating sloped portions 90 located at distal -14-

ends of the inwardly directed, sloped ledges 62 to limit the extent to which the sliding member 64 can be moved towards the distal end 54 of the body member 48. Proximal ends of the inwardly directed, sloped ledges 62 include angled guide portions 92 that direct the sliding member 64 into the through slot 50 during assembly of the coupler 12.

As seen in FIGS. 2 and 3, the proximal end 52 of the body member 48 includes a fastening member 94, such as a luer fitting, defined by a first cylindrical portion 96, a second cylindrical portion 98 and a third cylindrical portion 100. A through opening 102 extends through the first, second and third cylindrical portions 96, 98 and 100 of the fastening member 94 and is in aligned registry with the through slot 50 of the body member 48.

As seen in FIG. 2, the first cylindrical portion 96 defines a first seat 104 and a second seat 106. The first seat 104 is sized to receive the proximal end 52 of the body member 48, such that the fastening member 94 can be readily bonded to the coupler 12 to form a fluid-tight seal. The second seat 106 is configured to closely receive a funnel member 108 defined by a base portion 110 and an integral funnel portion 112. The base portion 110 is received within the second seat 106 and includes an opening 114 in aligned registry with the through opening 102 of the fastening member 94. As seen in FIG. 4, the funnel portion 112 is semi-cylindrical in shape and tapers radially outward from the opening 114 in the base portion 110 such that the funnel portion 112 extends partially into the proximal end 52 of the body member 48. The funnel portion 112 is adapted to guide the hypotube 28 of the catheter 14 into the opening 114 and the through opening 102 as the hypotube 28 is being inserted into the through slot 50 of the coupler 12. As seen in FIGS. 2 and 3, the second cylindrical portion 98 defines a third seat 116 that is configured to closely receive an annular seal, such as an 0-ring 118. The 0-ring 118 receives the hypotube 28 of the catheter 14 and forms a fluid-tight seal between the body member 48 and the catheter 14 such that inflation medium from the inflation assembly 16 must travel up the hypotube 28. The third cylindrical portion 100 of the fastening member 94 includes a threaded exterior portion 120 that cooperates with a threaded interior portion 122 of the luer-lock connector 36. The cooperation of the exterior and interior threaded portions 120 and 122 forms a readily releasible fluid-tight seal between the coupler 12 and the inflation assembly 16. As seen in FIGS. 5-7, the catheter exchange apparatus 10 further includes a snap-fit connector 126 for releasibly coupling an extension wire 128 to the catheter 14 once the catheter 14 has been disengaged from the coupler 12. The snap-fit connector 126 includes a female connector member 130 defined by a tubular portion 132 fixed to a mating end 134 (i--^., distal end) of the extension wire 128 by way of a spacer 135a (see FIG. 6) . The spacer 135a is brazed or otherwise bonded to the extension wire 128 and the tubular portion 132. The extension wire 128 has a guide portion 136a that extends distally beyond the tubular portion 132. The tubular portion 132 includes a -16-

concentric groove 133 that forms an inwardly extending concentric ridge 140 (see FIG. 6) .

As seen in FIGS. 5 and 6 the tubular portion 132 is configured to receive concentrically therein a 5 male connector member 142 defined by a tubular segment 144 that forms part of a proximal end of the hypotube 28. The hypotube 28 is received concentrically within the tubular segment 144 and is secured thereto by bonding or brazing. The tubular segment 144 includes a

10 concentric groove 146 that forms a concentric channel 148. The concentric channel 148 is adapted to receive the concentric ridge 140 in a snap-fit manner when the tubular segment 144 is inserted into the tubular portion 132 to thereby affirmatively and releasibly secure the

15 extension wire 128 to the hypotube 28 of the catheter 14. As seen best in FIG. 6, the guide portion 136a of the extension wire 128 is concentrically received within the tubular segment 144 when the extension wire 128 is coupled to the catheter 14. In addition, the guide

20 portion 136a acts as a guide and assists in initially aligning the tubular segment 144 with the tubular portion 132 during the coupling procedure.

As seen in FIGS. 5 and 6, the tubular portion 132 includes a longitudinal slot 150 extending distally

25 beyond the concentric ridge 140. The longitudinal slot 150 allows the tubular portion 132 to expand radially outward to a small extent to permit the tubular segment 144 to be easily inserted into the tubular portion 132. However, the tubular portion 132 may include a plurality

30 of longitudinal slots 150 equally spaced concentrically about the tubular portion 132 to make it easier to insert the tubular segment 144 into the tubular portion -17-

132. As a further alternative, the tubular portion 132 may not include a longitudinal slot 150, which may make insertion of the tubular segment 144 into the tubular portion 132 somewhat more difficult but may result in a greater gripping force between the tubular segment 144 and tubular portion 132 such that they may not be easily decoupled. The spring nature of the tubular portion 132 allows the tubular portion 132 to retain its initial configuration after coupling between the catheter 14 and the extension wire 128.

As seen in FIG. 6, the tubular segment 144 further includes a stop member, such as a concentric collar 154 that is configured to be engaged by a distal end 155 of the tubular portion 132 to indicate when the concentric ridge 140 is fully received within the concentric channel 148. In addition, a proximal end 156 of the tubular segment 144 abuts a distal end 157 of the spacer 135a to further indicate that the concentric ridge 140 is fully received within the concentric channel 148. As seen in FIG. 2, the collar 154 abuts the base portion 110 of the funnel member 108 to limit the extent to which the tubular segment 144 of the hypotube 28 extends into the through opening 102 of the fastening member 94 and thereby defines a fully seated state of the hypotube 28 of the catheter 14 within the through slot 50 of the coupler 12.

As seen in FIG. 8, the catheter exchange apparatus 10 further includes a pathway tube 158 that can be slid over the coupled extension wire 128 and catheter 14 (as represented by the directional arrow 160) . A distal end 162 of the pathway tube 158 is positioned across the stenosis such that the non-over- -18-

the-wire catheter 14 (with the extension wire 128 attached) can be removed from a patient's vascular system and replaced with a second non-over-the-wire catheter without reestablishing the pathway through the vascular system to the stenosis. In addition, the distal end 162 of the pathway tube 158 acts as a temporary stent when in place across the stenosis, and helps prevent the stenosis from collapsing back to an undilatated state. An alternative guide portion 136b is illustrated in FIG. 9. A bulb member 164a is formed on the guide portion 136b proximally of a distal end 166 of the guide portion 136b. The bulb member 164a is configured to override in a snap-fit manner a concentric crest 168 formed by the concentric groove 146 when the tubular segment 144 is inserted into the tubular portion 132. The interaction of the bulb member 164a and the concentric crest 168 acts as a further measure in addition to the interaction of the concentric ridge 140 and the concentric channel 148 to affirmatively and releasibly secure the extension wire 128 to the hypotube 28 of the catheter 14.

An alternative bulb member 164b is illustrated in FIG. 10. The bulb member 164b is defined by a concentric ber 170a formed in a tube segment 172. The tube segment 172 is configured to be brazed or otherwise bonded to the extension wire 128 to form a guide portion 136c that functions in a manner similar to that described above in relation to the guide portion 136b. A further alternative guide portion 136d is illustrated in FIG. 11. The guide portion 136d includes a first bulb member 164c and a second bulb member 174 -19-

spaced proximally from the first bulb member 164c. The first and second bulb members are formed on the extension wire 128. The first bulb member 164c functions in a manner similar to that described above in relation to the bulb member 164a. The second bulb member 174 acts as a stop for the concentric crest 168 and indicates that the concentric ridge 140 is fully received within the concentric channel 148 and that the first bulb member 164c has overridden the concentric crest 168.

A still further alternative guide portion 136e is illustrated in FIG. 12. The guide portion 136e includes a tubular spacer 135b defined by a proximal, first tubular part 176 brazed or otherwise bonded to the tubular portion 132. The tubular spacer 135b further includes an intermediate tapered part 178 formed at a distal end 180 of the first tubular part 176. The tapered part 178 extends radially inward with respect to the tubular part 176. A distal, second tubular part 182 is further formed at a distal end 184 of the tapered part 178 and includes a neck portion 186 and a concentric berm 170b defining a bulb member 164d. The mating end 134 of the extension wire 128 is brazed or otherwise bonded to the second tubular part 182 of the spacer 135b to secure the extension wire 128 to the tubular portion 132. The bulb member 164d of the guide portion 136e functions in a manner similar to that described above in relation to the bulb member 164a of the guide portion 136b. As seen in FIG. 12, the proximal end 156 of the tubular segment 144 abuts the tapered part 178 of the spacer 135b to indicate that the concentric ridge 140 is fully received within the -20-

concentric channel 148, and that the bulb member 164d has overridden the concentric crest 168. The proximal end 156 of the tubular segment 144 is tapered to cooperate with the tapered part 178. METHOD OF CATHETER EXCHANGE

To introduce a first non-over-the-wire catheter 14 into a stenosed coronary artery, a guide catheter (not shown) is first positioned within the vascular system of a patient. The distal end of the guide catheter is inserted into the femoral artery located in the thigh of the patient and pushed distally up through the vascular system until a distal end of the guide catheter is located in the ostium of the coronary artery. The proximal end of the guide catheter protrudes outside of the patient's body to provide an entryway for subsequent insertion of additional angioplasty devices. Thus, the guide catheter establishes a pathway from outside the body (at the thigh) to the ostium of the coronary artery adjacent the stenosis.

Next, a first non-over-the-wire catheter 14 in accordance with the present invention is prepared for use by securing the inflation assembly 16 to the hypotube 28 of the first catheter 14. This is accomplished by first securing the coupler 12 to the inflation device 32 via the threaded interengagement of the threaded exterior portion 120 of the fastening member 94 and the threaded interior portion 122 of the luer-lock connector 36. With the sliding member 64 in the first state, the hypotube 28 is then inserted into the through slot 50 of the body member 48 such that the tubular segment 144 extends into the through opening 102 and through the O-ring 118 and opening 114 and the collar 154 abuts the base portion 110 of the funnel member 108. In this position, the first catheter 14 is in the fully seated state within the coupler 12. The sliding member 64 is then moved from the first state to the second state wherein the tubular segment 144 of the hypotube 28 of the first catheter 14 is firmly gripped between the engagement surface 76 and the planar bottom wall 58 (see FIGS. 1 and 2) . The sliding member 64 is held in the second state by frictional engagement between the oppositely directed, angled channels 72 and the inwardly directed, sloped ledges 62.

The first catheter 14 of the assembled combination of the first catheter 14, coupler 12 and inflation assembly 16 is then inserted within the proximal end of the guide catheter. Next, the first catheter 14 is pushed through the guide catheter and steered through the ostium of the coronary artery and the arterial branches of the vascular system of the patient until the balloon 20 of the first catheter 14 is positioned as desired across the stenosis.

Upon a complete and successful positioning of the balloon 20 within the stenosis, the balloon 20 of the first catheter 14 is inflated to dilatate the stenosis. Dilatation of the stenosis can be repeated at various pressures until an acceptable reduction in the stenosis is achieved and blood flow through the stenosed area is improved. Sometimes after a successful installation, the balloon 20 of the first catheter 14 is too large to fit through the stenosis or so small that the stenosis cannot be fully dilatated. When this occurs, the first catheter 14 must be exchanged for a second non-over-the-wire catheter which is identical to the first catheter 14 except that the second catheter has ,a different balloon profile.

To exchange the first catheter 14 for the second catheter in accordance with the present invention the inflation assembly 16 and coupler 12 combination is first removed from the first catheter 14. This is accomplished by moving the sliding member 64 from the second state back to the first state thereby allowing the hypotube 28 of the first catheter 14 to be removed from the through slot 50 of the coupler 12. Next, tubular portion 132 of the extension wire 128 is coupled in a snap-fit manner to the tubular segment 144 of the hypotube 28 to extend the length of the first catheter 14 (see FIG. 7) .

The pathway tube 158 is then slid over the extension wire 128 and first catheter 14 combination (see FIG. 8) until the distal end 162 of the pathway tube 158 is positioned within the stenosis and surrounding the balloon 20. A proximal end of the pathway tube 158 extends outside of the patient's body. Next, while holding the pathway tube 158 in position across the stenosis, the first catheter 14 is removed from the patient's vascular system by pulling the first catheter 14 and extension wire 128 combination proximally out of the pathway tube 158 and thereby from the patient's body. The pathway tube 158 acts as a temporary stent and helps prevent the stenosis from collapsing back to an undilatated state. The extension wire 128 is then decoupled from the first catheter 14 by disengaging the tubular segment 144 from the tubular portion 132. Next, the extension wire 128 is coupled to the hypotube of the second non- over-the-wire catheter in the same manner as described above in relation to the first catheter 14 (see FIG. 7) . Next, while holding the pathway tube 158 in position across the stenosis, the second catheter is introduced into the patient's vascular system. This is accomplished by pushing the second catheter and extension wire 128 combination distally through the pathway tube 158 until the balloon of the second catheter is positioned across the stenosis within the distal end 162 of the pathway tube 158. The pathway tube 158 acts as a conduit such that the exchange of the first catheter 14 for the second catheter can be accomplished without reestablishing the path through the patient's vascular system to the stenosis.

With the balloon of the second catheter held in place across the stenosis, the pathway tube 158 is removed from the patient's body by pulling the pathway tube 158 proximally out over the second catheter and extension wire 128 combination (see FIG. 8) . Next, the extension wire 128 is decoupled from the second catheter and the inflation assembly 16 and coupler 12 combination is secured to the hypotube of the second catheter in the same manner as described in relation to the first catheter 14 (see FIG. 1) . Upon a complete and successful positioning of the balloon of the second catheter within the stenosis, the balloon is inflated to dilatate the stenosis.

An alternative method of catheter exchange is illustrated in FIG. 13. The first catheter 14 is introduced and removed from the vascular system of the patient in the same manner as described above in the previous method of exchange. The first catheter 14 is exchanged for a second catheter 188, which is identical to the first catheter 14 except that a balloon 190 of the second catheter 188 has a different profile. The inflation assembly 16 and coupler 12 combination is secured to a hypotube of the second catheter 188 in the same manner as set forth above in relation to the previous method of exchange.

With the inflation assembly 16 and coupler 12 combination secured to the second catheter 188, the second catheter 188 is introduced into the patient's vascular system in the same manner as described above in relation to the previous method of exchange. The second catheter 188 is pushed distally through the pathway tube 158 until the balloon 190 of the second catheter 188 is positioned so as to extend across the stenosis within the distal end 162 of the pathway tube 158.

The pathway tube 158 is then slid proximally (as represented by the directional arrow 192) along the second catheter 188 (but is not removed from the second catheter 188) until the distal end 162 of the pathway tube 158 is no longer positioned across the stenosis. This procedure exposes the balloon 190 of the second catheter 188 that is in position across the stenosis. The balloon 190 of the second catheter 188 is then inflated to dilatate the stenosis.

A further alternative method of catheter exchange is illustrated in FIG. 14. In the embodiment, the first catheter 14 is introduced and removed from the vascular system of the patient in the same manner as described above in relation to the first method of exchange. However, the first catheter 14 is exchanged for a second catheter 194 of conventional design. A distal end of the second catheter 194 includes a balloon 196 having a different profile than the balloon 20 of the first catheter 14. A proximal end of the second catheter 194 includes a luer fitting 198 to which an inflation assembly 16 can be secured.

With the inflation assembly 16 secured to the second catheter 194, the second catheter 194 _s introduced into the patient's vascular system in the same manner as described above in relation to the first method of exchange. The second catheter 194 is pushed distally through the pathway tube 158 until the balloon 196 of the second catheter 194 is positioned so as to extend across the stenosis within the distal end 162 of the pathway tube 158.

The pathway tube 158 is then slid proximally (as represented by the directional arrow 200) along the second catheter 194 (but is not removed from the second catheter 194) until the distal end 162 of the pathway tube 158 is no longer positioned across the stenosis. This procedure exposes the balloon 196 of the second catheter 194 that is in position across the stenosis. The balloon 196 of the second catheter 194 is then inflated to dilatate the stenosis. This catheter exchange apparatus 10 is relatively uncomplicated and allows a first non-over- the-wire catheter 14 to be exchanged for a second non- over-the-wire catheter without having to reestablish the pathway through the patient's vascular system. As such, this catheter exchange apparatus 10 reduces the risk of the second catheter entering a false lumen and makes the procedure of inserting the catheter through the arterial tree a less difficult procedure.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

-27-WHAT IS CLAIMED IS:

1. A coupler for readily, releasibly securing an inflation assembly to a tubular proximal portion of a non-over-the-wire catheter which is adapted to have a distal portion thereof inserted into a patient's vascular system, the coupler comprising: a body member having a through slot extending from a proximal end of the body member to a distal end thereof for releasibly receiving the tubular proximal portion of the non-over-the-wire catheter, and including: a first generally planar engagement surface; a sliding member having a second generally planar engagement surface which is parallel to and spaced from the first engagement surface, the sliding member being movable between a first state wherein the tubular proximal portion of the catheter is insertable into the through slot, and a second state wherein the tubular proximal portion is gripped between the first and second engagement surfaces and thereby secured to the coupler; and a fastening member attached to the proximal end of the body member for engaging a distal end of the inflation assembly and thereby -28-

readily, releasibly securing the inflation assembly to the tubular proximal portion of the catheter such that the catheter is in fluid medium communicaticn with the inflation assembly.

2. The coupler of claim 1 wherein the fastening member is a luer fitting having a threaded portion that cooperates with a threaded portion of the inflation assembly.

3. The coupler of claim 1 wherein the fastening member includes a through opening in aligned registry with the through slot of the body member such that the tubular proximal portion of the catheter extends partially into the through opening when the catheter is secured to the coupler.

4. The coupler of claim 3 wherein the body member further includes a seal member forming a fluid-tight seal between the coupler and the tubular proximal portion of the catheter.

5. The coupler of claim 4 wherein the seal member is an 0-ring secured in the fastening member and extending concentrically about the through opening.

6. The coupler of claim 3 wherein the tubular proximal portion of the catheter includes a stop member which abuts a stop portion of the body member to limit the extent to which the tubular proximal portion extends -29-

into the through opening of the fastening member and thereby define a fully seated state of the catheter within the coupler.

7. The coupler of claim 6 wherein the stop portion of the body member includes a funnel member secured in the fastening member.

8. The coupler of claim 7 wherein the funnel member includes: a base portion having an opening in aligned registry with the through opening of the fastening member; and a funnel portion joined to the base portion for guiding the tubular proximal portion of the catheter into the through opening of the fastening member.

9. The coupler of claim 8 wherein the funnel portion is semi-cylindrical in shape and tapers outwardly from the opening in the base portion and extends partially into the proximal end of the body member.

10. The coupler of claim 8 wherein the stop member is a collar extending concentrically about the tubular proximal portion of the catheter, the collar abutting the base portion of the funnel member in the fully seated state of the catheter.

11. The coupler of claim 1, and further including: an extension section having a mating end; -30-

a mating end on the tubular proximal portion of the catheter; and a connector for releasibly coupling the extension section to the catheter including: a female connector member on the mating end of one of the extension section and the tubular proximal portion; and a male connector member on the mating end of the other one of the extension section and tubular proximal portion which is configured to securely engage the female connector member and thereby secure the extension section to the catheter.

12. The coupler of claim 11 wherein the male connector member includes a tubular segment that is configured to be readily received concentrically within a tubular portion of the female connector member.

13. The coupler of claim 12 wherein the tubular portion includes a concentric groove that forms an inwardly extending concentric ridge, and the tubular segment includes a concentric groove that forms a concentric channel that is configured to receive the concentric ridge in a snap-fit manner to affirmatively and releasibly secure the extension section to the catheter.

14. The coupler of claim 13 wherein the tubular portion further includes at least one longitudinal slot that allows the tubular portion to expand radially outwardly to permit the tubular segment of the male connector member to be received within the tubular portion of the female connector member.

15. The coupler of claim 13 wherein the male connector member is on the mating end of the tubular proximal portion of the catheter and the female connector member is on the mating end of the extension section.

16. The coupler of claim 15 wherein the extension section further includes a guide portion extending through the tubular portion that is configured to be concentrically received within the tubular segment when the extension section is releasibly secured to the catheter.

17. The coupler of claim 16 wherein the concentric groove of the tubular segment forms an inwardly extending concentric crest and the guide portion includes a bulb member that is configured to override in a snap-fit manner the concentric crest when the extension section is releasibly secured to the catheter.

18. The coupler of claim 17 wherein a tube segment is secured to the guide portion, the tube segment including a concentric berm that defines the bulb member.

19. The coupler of claim 16 wherein the guide portion further includes a second bulb member spaced proximally from the first bulb member, the second bulb member abutting the concentric crest when the extension section is releasibly secured to the catheter.

20. The coupler of claim 1 wherein the body member further includes a first pair of ramped surfaces and the sliding member further includes a second pair of ramped surfaces which ride upon the first pair of ramped surfaces upon longitudinal movement of the sliding member relative to the body member, to move the second engagement surface toward the first engagement surface as the sliding member moves from the first state toward the second state.

21. An extendable non-over-the-wire catheter, comprising: a catheter tube which includes a main portion configured to be inserted into a patient's vascular system and a first mating end configured to extend out of the patient; an extension section having a second mating end; and a connector for coupling the extension section to the catheter tube, including: a female connector member on one of the first and second mating ends, including: a tubular portion having a concentric groove that forms -33 -

an inwardly extending concentric ridge; and a male connector member on the other one of the first and second mating ends, including: a tubular segment having a concentric groove that forms a concentric channel, wherein the tubular segment is readily received concentricallywithin the tubular portion, and wherein the concentric channel is configured to receive the concentric ridge in a snap-fit manner to affirmatively and releasibly secure the first and second mating ends of the catheter tube and extension section, respectively.

22. The extendable catheter of claim 21 wherein the tubular portion further includes at least one slot extending along a longitudinal extent of the tubular portion that allows the tubular portion to expand radially outwardly to permit the tubular segment of the male connector member to be received within the tubular portion of the female connector member.

23. The extendable catheter of claim 22 wherein the male connector member is on the first mating end of -34-

the catheter tube and the female connector member is on the second mating end of the extension section.

24. ^' The extendable catheter of claim 23 wherein the extension section further includes a guide portion extending through the tubular portion that is configured to be concentrically received within the tubular segment when the extension section is releasibly secured to the catheter tube.

25. The extendable catheter of claim 24 wherein the concentric groove of the tubular segment forms an inwardly extending concentric crest and the guide portion includes a bulb member that is configured to override in a snap-fit manner the concentric crest when the extension section is releasibly secured to the catheter tube.

26. The coupler of claim 25 wherein a tube segment is secured to the guide portion, the tube segment including a concentric berm that defines the bulb member.

27. The coupler of claim 25 wherein the guide portion further includes a second bulb member spaced proximally from the first bulb member, the second bulb member abutting the concentric crest when the extension section is releasibly secured to the catheter tube.

28. An inflation assembly that can be readily, releasibly secured to a tubular proximal portion of a non-over-the-wire catheter which is adapted to have a -35-

distal portion thereof inserted into a patient's vascular system, comprising: a coupler joined to the inflation assembly including a through slot having a generally planar bottom wall extending form a proximal end to a distal end thereof, the through slot releasibly receiving the tubular proximal portion of the catheter such that the tubular proximal portion is in fluid communication with the inflation assembly, and including: a sliding member having a generally planar engagement surface which is parallel to and spaced from the planar bottom wall, the sliding member being movable between a first state wherein the tubular proximal portion of the catheter can be freely inserted into the through slot, and a second state wherein the tubular proximal portion of the catheter is gripped between the engagement surface and the planar bottom wall and thereby secured to the inflation assembly.

29. The inflation assembly of claim 28 wherein the coupler includes a seal member forming a fluid-tight seal between the inflation assembly and an exterior region of the tubular proximal portion of the catheter.

30. The inflation assembly of claim 28 wherein the tubular proximal portion of the catheter includes a stop member which abuts a stop portion of the coupler to limit the extent to which the tubular proximal portion extends into the through slot to thereby define a fully seated state of the catheter within the inflation assembly.

31. The inflation assembly of claim 30 wherein the stop portion of the body member includes a funnel member secured within the coupler.

32. The inflation assembly of claim 31 wherein the funnel member includes: a base portion having an opening in aligned registry with the through slot; and a funnel portion joined to the base portion for guiding the tubular proximal portion of the catheter into the proximal end of the coupler.

33. The inflation assembly of claim 32 wherein the funnel portion is semi-cylindrical in shape and tapers outwardly from the opening in the base portion.

34. The inflation assembly of claim 33 wherein the stop member is a collar extending concentrically about the tubular proximal portion of the catheter that abuts the base portion of the funnel member in the fully seated state of the catheter.

35. The inflation assembly of claim 28 wherein the coupler includes a first ramped surface and the sliding member further includes a second opposed ramped surface which rides upon the first ramped surface upon longitudinal movement of the sliding member relative to the coupler, to move the engagement surface toward the planar bottom wall as the sliding member moves from the first state toward the second state.

36. A method of exchanging a first non-over-the- wire catheter within the vascular system of a patient for a second non-over-the-wire catheter, comprises the steps of: decoupling an inflation assembly from a catheter tube of the first catheter; securing an extension wire to a proximal end of the first catheter to form a first catheter and extension wire combination; sliding a pathway tube over the first catheter and extension wire combination such that a distal end of the pathway tube surrounds a balloon of the first catheter within a stenosis within the vascular system of a patient; holding the pathway tube to maintain the distal end thereof within the stenosis; withdrawing the first catheter and extension wire combination from the pathway tube and thereby from the vascular system of a patient; detaching the extension wire from the proximal end of the first catheter; securing the extension wire to a proximal end of a second catheter to form a second catheter and extension wire combination; inserting the second catheter and extension wire combination into the pathway tube; pushing the second catheter and extension wire combination through the pathway tube until a balloon of the second catheter is positioned in the distal end of the pathway tube within the stenosis in the vascular system of a patient; holding the second catheter and extension wire combination to maintain the balloon of the second catheter within the stenosis; withdrawing the pathway tube from around the second catheter and extension wire combination and thereby from the vascular system of a patient; detaching the extension wire from the proximal end of the second catheter; and securing the inflation assembly to the proximal end of the second catheter such that the second catheter is in fluid medium communication with the inflation assembly.

37. A method of exchanging a first non-over-the- wire catheter within the vascular system of a patient for a second non-over-the-wire catheter, comprises the steps of: decoupling an inflation assembly from a -39-

catheter tube of the first catheter; securing an extension wire to a proximal end of the first catheter to form a first catheter and extension wire combination; sliding a pathway tube over the first catheter and extension wire combination such that a distal end of the pathway tube surrounds a balloon of the first catheter within a stenosis within the vascular system of a patient; holding the pathway tube to maintain the distal end thereof within the stenosis; withdrawing the first catheter and extension wire combination from the pathway tube and thereby from the vascular system of a patient; securing the inflation assembly to the proximal end of a second catheter such that the second catheter is in fluid medium communication with the inflation assembly; inserting the second catheter into the pathway tube; pushing the second catheter through the pathway tube until a balloon of the second catheter is positioned in the distal end of the pathway tube within the stenosis in the vascular system of a patient; and sliding the pathway tube proximally along the second catheter until the distal end of the pathway tube is no longer positioned within the stenosis, thereby exposing the balloon of the second catheter that is in position across the stenosis.