CA2113259C

CA2113259C - Transformable catheter

Info

Publication number: CA2113259C
Application number: CA002113259A
Authority: CA
Inventors: Larry D. Paskar
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-07-15
Filing date: 1992-07-13
Publication date: 1999-01-12
Anticipated expiration: 2012-07-13
Also published as: WO1993001857A1; JP3191939B2; JPH07501953A; CA2113259A1; EP0607155A4; US7022102B2; EP0607155A1; US20030199960A1; US5304131A

Abstract

A medical tube (31) has at least one wire (37) running from the proximal end to the vicinity of the distal end, which wire (37) is connected to the tube adjacent the distal end so as to allow the distal tip to be deflected upon movement of the wire. The tube has gaps (71) therein on one side as to form a predetermined region of weakness, whereby upon tension being applied to the wire (37) the distal end of the tube bends in the direction of the predetermined region of weakness. The medical tube may be a sheath (33) in which is disposed a preformed inner catheter (35) having a complex curve formed into the distal end thereof. By suitable manipulation of the wire (37) and of the inner catheter (35) with respect to the sheath (33) the shape of the exposed portion of the distal end of the inner catheter may be transformed to a variety of shapes.

Description

WO 93/OlX57 2 1 1 3 2 5 9 PCr/USg2/05833 -Tra~,~ro""able r~ot1.~
Background of the Invention This invention relates generally to medical devices ! and more particularly to a catheter which can be formed, inside the human body, into a vast number of different shapes.
Selective catheterization of cerebral and visceral branch arteries is often difficult and at times impossible in some patients -- particularly older patients with very tortuous and ectatic vasculature. Successful catheterization sometimes requires multiple catheter exchanges for various shaped catheters. It is not uncommon to easily catheterize three of four vessels for a four vessel head study, only to find that the fourth vessel (generally the left or right carotid) requires an entirely different catheter shape and tip orientation. It would be desirable if one could easily and simply reshape the catheter and reorient the tip to direct it into the vessel orifice, instead of d~ren~ing on several complex catheters that require reformation, fancy torque and advancing maneuvers, body english and, above all, luck.
- Tip reorientation, the goal of most prior devices which have a~ the problem, is oniy half of what is needed to make a truly workable universal catheter. Numerous catheter curve configurations ha~e been conceived not only to reorient the tip properly for selection of branch vessels, but also to provide A~h~rage of the catheter against the aortic wall.- A
wide looped~long~ tipped sidëwinder III~configuration with.an.~.
exaggeratëd rretlG~L~e ls one such example of a highly .
specialized complex catheter.
. . ..
This ~h~rage or wedge effect a~inct the aortic wall le-~?n~ the recoil caused by the ~jet effect~ during high.
pressure:contrast injection which might otherwise aause the catheter to flip out of the selècted branch vessel (particularly in short branch vessels or at lëvels of a dilated aorta).
These complex configurations, therefore,.evolved not only to orient the tip properly, but also to wedge the catheter securely in the branch vessel. Other devices which simply modify the distal catheter curve may aid in tip orientation for vessel SIIBSTITUTE SHET

WO93/01857 ' PCT/US92/0~
211325~ - 2 -selection, but fail to provide the anchorage which is necessary to prevent catheter dislodgement.
In addition, prior designs could be improved in that the radii which the prior devices are able to make (to enter a vessel at a sharp angle, for example) have heretofore been severely limited.
Moreover, the size of prior designs has made them less desirable for many applications.
In certain applications (for example, complex interventional procedures such as angioplasties or intracerebral procedures), current catheters could be improved with respect to their ability to facilitate crossing of tight s~eno~es or with respect to their trackability out into peripheral branches.
In this respect, the current catheters could be improved in the areas of displacing forces from the application site at the point of catheter i.-L~od~ction (most often in the inguinal area) to points close to the actual catheter tip. This would increase the control that a user, such as an angiographer, has on the catheter, creating a more precise local longitudinal vector force for crossing tight stenoses, and also increase torque force for ;Aing the catheter tip toward the orifice of a selected vessel.
In would also-be desirable to have a catheter construction which provided ~c.,~lollable variability in the distal catheter stiffness. Such a catheter could be stiffened for support close to a first order selected branch through which a more flexible catheter could be tracked peripherally. Conversely, such a catheter could be made less stiff over variable dista~ces to allow better tr~c~in~of a more flexible distal end over~-a--~ire.
Summary of the T~vention Among the various objects and features of the present invention may be noted the provision of a catheter which--simplifies the~catheterization pro~ed~Le. - ~
A ~eco~A object is the provision of such a catheter which significantly reA11seC the number of catheterizations required for any particular medical procedure.

wo g3/0~8s7 2 1 1 3 2 5 9 PCT/US92/05833 .

A third object is the provision of such a catheter which can be easily and simply ~ re~ into a variety of different shapes as desired by the user.
A fourth object is the provision of such a catheter which can mimic almost any catheter configuration, and can thereafter be reformed in the body to other desired shapes.
A fifth object is the provision of such a catheter which obviates the need for multiple catheter ex~An~es, thereby reducing the time involved in a medical ~r~ re and also reducing the possibility of complications.
A sixth object is the provision of such a catheter which provides adequate anchorage of the catheter against the aortic wall to re~l~c~ the ~jet effect.
A seventh object is the provision of such a catheter which is car~hle of achieving an improved curve radius at its distal end.
An eighth object is the provision of su~h a catheter which is significantly reduced in size compared to the prior devices.
A ninth object is the provi8ion of such a catheter which will di~place longit~în-l vector force from the site of .. . . . . . .
a~rlic~tion in the groin of the patient to a point near the tip of the cath ter, thereby facilitating the cro~ci~ of tight ~tenoses d ~ angioplasty procc~u~e_. ' A tenth object is the provision of such a catheter which will ~i~rlr~e torque force from the site of application in the groin of the patient to a point near the tip to facilitate more pre~i~e torgue of the catheter *ip, improving~the~ability to " ~ . ~,i r,; ,, ~; ' ''' Qnter r~l ç~d~
An ecla~e..~h object is the provision of such a catheter which wili provide variable stiffness at the'distal end that wili facilitate~catheter advancement peripherally when it serves as a 8tiffened ~ near a first order take off vessel and'will lik~wi~e fr~ tate trA~in~ over a guidewire when made more 7O ~ver a variable distance, distally.
Other ob~ects will be in part apparent and in part pointed out hereinafter.
:~:

W093/01857 ' ' PCT/US92/058~
2113259 - 4 - ' ' Briefly, a catheter of the present invention includes a catheter tube having a wall and an internal lumen exten~ing substantially through the length of the catheter tube, the catheter tube having an outside diameter sufficiently small so that the catheter tube may be inserted into the human body and having a proximal end and a distal end. At least one wire runs from the proximal end of the catheter tube to the vicinity of the distal end of the catheter tube, which wire is connected to the catheter tube adjacent the distal end so as to allow the distal tip of the catheter tube to be deflected upon movement of the wire. The catheter tube has a substantially uniform transverse cross section throughout a substantial part of its length, and the catheter tube wall adjacent the distal end of the catheter tube has gaps therein on one side of the longitudinal axis of the catheter tube so as to form a predetermined region of weakness.
Upon tension being applied to the wire, the distal end of the catheter tube h~n~c in the direction of the predetermined region of weAknecc.
In a second aspect of the p,~~?nt invention, a transformable catheter includes a sheath having a diameter sufficiently small 80 that the sheath may be inserted into blood vessels of the human body, the sheath having'a length which is a substantial fraction of the entire length of the transformable catheter. The sheath also has a bore therethrough r~nnin~ substantially from the proximal end of the sheath to the distal end of the sheath.
A preformed inner catheter has a complex curve formed into the distal end thereof, and i8 sized to fit in the sheath bore. The inner catheter is axially movable with respect'to~'thé''sheath in the ~bore,~the sheath being~ufficiently'rigid and'the inner catheter hein~ sufficiently pliable~so that withdrawal of the inner catheter into the-sheath substantially straightens out the portion~of the complex curve of the distal tip contAineA within the sheath. The distal tip resumes its complex curve shape'upon movement thereof out of the sheath-bore. The user àxially moves the inner catheter with ~ to the bore to expose only so much of the distal end of the inner catheter as to cause the ~C093/01857. - 2 1 1 3 2 5 9 PCT/US92/0~33 _ 5 _ ::
eYroFeA portion of the distal end of the inner catheter to take a desired ~Ar~. The inner catheter has a length substantially eGl ~ ~ ~ronding to the length of the transformable catheter. At least one wire runs from the proximal end of the sheath to the vicinity of the distal end of the sheath, the wire being connected to the sheath adjacent the distal end ~o as to allow the distal tip of the sheath to be deflected upon movement of the wire. By suitable manipulation of the wire and of the inner catheter with l~-pect to the sheath, the shape of the ex~o-~cd portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of r~pe~ as desired by the user. The sheath has at its distal end a predetermined region of weakne~s so that upon tension h~in~ applied to the wire, the distal end of the sheath ~nA~ in the direction of the predetermined region of weakness.
Although the invention is described in connection with blood v~-~el~, it is not so limited. It may be used not only in arterial and ~..ou_ brAn~ec, but also in the biliary tree, urinary tract, body cavities (such as the thorax and abdomen), hollow vî~cous organs (such as the stomach, intestines, and ~-~ urinary bladder).. , cysts and A~ e~ --' in short, in any place '-where ~eleckive direction and reformation of-a'catheter,'tube or guidewire i8 required. ' The method of the ~ ~ nt i-.ve-.Lion includes changing the ~:
~ ~hape of a catheter in a human body. It includes the steps of inserting a combination catheter into a cavity of a human'body.
The combination catheter has;a ~heath'~with a lèngth'which is a ub~tantial fraction~of-the entire lèngth-'of'~the"combination .
catheter. f.The comb.in.ation.catheter also has'à prèformed inner catheter with a complex curve formed into"the'~distal end thereof disposed. in~the.bore of the sheath. The user axially moves the inner catheter with~ rect to'the bore to e'x~ only'so much of ~ the distal end of the inner catheter as to:caûse-the eY~o~6~
~ portion of the.distal end of the inner catheter to take a desired ~hape.. - ~ . ' ~ .

WOg3/01857 '' ' '' '''" PCT/US9~0583~

Brief Description of the Drawings Figs. lA - lB, and lD are side elevations illustrating the cG,~LL~ction of the transformable catheter of the p~ t invention; - ' Fig. lC is a top plan of the proximal portion of the transformable catheter of the ~ ent invention;
Fig. lE is a view, similar to Fig. lD but on an enlarged scale, illustrating the construction of a side port of the transformable catheter of the present invention;
Figs. 2A - 2D are simplified elevations illustrating some of the myriad ~re~ which are at~Ain~hle with the transformable catheter of the p~-ent invention;
Figs. 3A - 3C are simplified elevations illustrating the reformation of a complex catheter shape inside the human body.
Figs. 4A - 4D are partial elevations illustrating operation of one embodiment of the ~-ent invention;
Fig. 5 is a partial elevation illustrating a gaF ~r~ -different from that shown in Figs. 4A - 4D;
Fig. 6 is a view similar to Fig. 5 illustrating another gap shape; , - , - -~ ,Fig. 7 ic a view similar to Fig. 4A illustrating ~n'alternative construction;~
Fig. 8 is a view similar to Fig. 4A showing a ~v.e~ing over the gaps;
Fig. 9 i8 a sectional view illustrating an alternative way to cause the catheter to bend in a de~ired direction;
~ Figs. lQ and ll,ill~L.aLe-the method of ~ol._L.~ ;nn of'an alt ~ i,v,,e,to~,*hat, o,f~,Figs.~,4A~--4D; and'~
, Fjig_.;-12 and 12A~ar,~e perspective views illu~L~aLing'an im~v.e~ h~n~i e of, the~ -ent invention. '''~ ' Similar reference characters indicate similar parts .,~ ~ , . ,, -throughout the several vieWC of the drawings.ri~i ~n of the Pref~rred EEpodiment- -- ' ,, ~, .,; ". . ...
, A catheter 31,(see Figs. lA - lC) of the p~.-ent invéntion in its cimplest form includes an enabling sheath 33, and an inner catheter 35 having a distal tip with a complex-curv~e Q~ape.

W O 93/01857 2 1 1 3 2 ~ 9 PC~r/US92/05833 Catheter 31 is especially suited for celective arterial catheterization. In that application, the catheter is custom shaped or formed while in the patient to make it easy to direct the tip in any orientation required to enter a branching orifice or serpiginous vessel. Catheter 31 is not a steerable catheter, ' but rather one which may be custom curved and recurved by the user to select each branch vessel. The catheter may also be used in the biliary tree and urinary tract to negotiate branches, corners, and serpiginous pathways.
As will become apparent in view of the following disclosure, ~anipulation of catheter 31 results in mimicking virtually any simple or complex curved configuration of selective arterial catheter ~ imaginable while the catheter i~ oscd in the patient. ni~e~rise~ modification of curve and tip orientations allow selection and direction of wire guides for other invasive pror~A~res such as percutaneous cholangiography and percutaneous nephrostomy; that is, any p~o~ e requiring direction or redirection of a catheter.
Inner catheter 35 i~ a complex memory curve catheter which runs in a co~Y~,Al manner through enabling sheath 33. With the complex tip completely,ex~en~e~ beyond the'sheath,ithé most complex tip configuration reforms. ' By pull'ing the inner catheter back through the enabling sheath to varying de~Lces (sheathing and ~ -~6~thing the inner catheter tip), various segments of the curve are ~i~G..ed outn -- thereby changing the overall catheter tip configuration and tip orientation. The inner catheter is the activ prima y component but is a passive p~qnger~with'respect to the ~-hlin,,g~sheath ,which acts upon the cathetër'to modify its shape. In add,itio~n,, the fact that the~transformation'takes place in a vessel in the human body further~modifies the shapes which can be achieved due to~interaction of the transformable catheter with the walls of the vessel. - '' ' ' ' Sheath 33,has the;capability of being formed by a pullwire 37 into a hook configuration, as described below. (Although described as a wire, item 37 could equivalently be made of high tensile strength suture or thread material.) This capability W093/01857 ~ ~ PCT/US92/058~

allows reformation of the complex memory curvature by directing the catheter tip downward while transformable catheter 31 is dispo~e~ in the aorta. Secondarily the sheath curve can, to some degree, act on the catheter to further modify the catheter shape.
In detail, transformable catheter 31 (see Figs. lA - lC) includes outer enabling ~heath 33 which extends almost the entire length of the catheter. It is preferred that sheath 31 be long enough so that only the complex curve distal end portion of the inner catheter extends beyond it. Inner catheter 35 is disposed in the central bore of sheath 33 and has the most exaggerated sidewinder preformed tip configuration distally. (Of course, any other similar complex-shaped memory curve inner catheter could also be used in the pL~-ent invention as inner catheter 35.) The distal end of enabling sheath 33 can be formed into a curve with up to one hundred and eighty degrees of curvature when retracted by pull wire 37 by the suitable application of tension to the pull wire. This allows the hook configuration of the sheath 33 to reform the catheter 35 when the catheter is advanced through the sheath. The variable curved tip also allows variation in the degree of curvature, modifying the natural memory curve and thereby the overall ~re of the catheter.
Enabling sheath 33 modifies the extreme natural curvature of catheter 35 by acting as a housing that irons out various segments of the curvature when the catheter is retracted back into the sheath. Such an ~ironing~ effect is illustrated in Fig.
2A. In Figs. 2 and 3, the various portions of transformable catheter 31 are shown in~simplified form'for ciarity. For example,~in~Fig.-2A,~the catheter 35'i~ shown exten~i~g distally from sheath 33 a small amount, while catheter ànd sheath are o-~ in a vessel (such as an artery) 41.~ ~
In Fig. 2B, the same catheter 35 is shown extended distally out of sheath 33 a small additional amount such that the catheter re~inC some of its curvature. Similarly, in Fi~s. 2C and 2D, catheter 35 is exte~ distally even further. Note that in Fig.
~ 2D, thé distal curved portion of catheter 35 is fully extended from sheath 33, but the original configuration of catheter 35 is r ~093/01857 2113 2 5 9 PCT/USg~ ~ 33 not obtained because of the interaction of the catheter ~ith vessel wall 41.
If the physician desires to instead shape or form catheter 35 back into its original, preformed shape of Fig. ~, the steps illustrated in Figs. 3A - 3C are followed. In this case-j the sheath is first formed (by use of retraction wire 37~ into the shape shown in Fig. 3A and Fig. 3B. As a result of this ~hape of the sheath, as catheter 35 i8 moved distally with respect to the sheath it assumes the form in the vessel as illustrated in Figs.
3A and 3B. The sheath is restraightened by suitable manipulation (i.e., release) of retraction wire 37 as shown in Fig. 3C as desired. This prsre~11re allows the original form of catheter 35 to be obt~;n~A in the v~ ~el.
Note, from comparing Fig. 2D with Fig. 3C, the great differences in catheter shape achievable by simple manipulation of sheath 33 and of the catheter with respect to the sheath. In fact Figs. 2A - 2D and 3A - 3C all illustrate some of the multitude of different catheter shapes which may be formed in the body, during a medical p~G~ re, using the present invention.
It ~o~ll d be realized that these ch~pe~ are merely illustrative and ~hat with suitable manipulation of the sheath and rélative movement Le~-ree.. the sheath~and the catheter-, a great number of additional catheter confi~a~ions may ~e achieved.
Note as well, that the particular configuration shown in Fig. 3B provides a tighter radius for the tip of catheter 31 than is Ac~ievable with prior devices due to the interaction of the complex-formed tip of the~inner catheter-and the deflection of the sheath. This greater.flexibility in the ihAp~c achièvable permits v~ to-be entered with the present catheter which were not r~ ly accessible with the prior devices.
Referring back to Figs. lA - lC, the inner catheter 35 travels through the enabling sheath in a coaxial manner, but is stiffeneq from its proximal end to a point just proximaL- to the distal exaggerated curvatures by an outer stiffening segment 43.
This outer etiffening segment is fused to the inner catheter proximally and distally and provides sufficient strength to the W093/01857 PCT/US92/058~
2113259 - lo -inner catheter to permit it to be moved axially with respect to the sheath without collapsing or bin~;ng.
Transformable catheter 31 is introduced in the usual manner through the femoral artery and advanced into the abdominal aorta. The catheter is reformed and selectively shaped-in the abdominal aorta. When initially introduced the inner catheter is in its ironed-out parked position within the enabling sheath with only a small distal tip segment protruding (see Fig. 2A). The pull wire 37 is retracted, forming a hooked curve (see Fig. 3A) which allows direction of the catheter tip downward and thereby easy reformation of the memory curve. Once reformed, the various sh~pes of the catheter can be selected by advancing or retracting the catheter into the enabling sheath, thereby allowing or disallowing the natural memory curves to form at various segments. Pull wire modification of the enabling sheath allows additional curved configurations.
Proximally, the stiffened inner catheter is pulled back through a plastic sleeve 45, slotted on either side. (See Figs.
lC and lD.) A fixation collar 47 at~ C to the proximal portion of the catheter. A molded spring ~V~ prong 49, rounded on one s~de and flat on the other, arises from the side of the collar and extends through the sleeve. The ~16~1y iS fixedly secured to catheter 35 and can be pulled through a right slot 51 , . .
of the sleeve (see Fig. lD), thereby pulling the catheter as a whole through the enabling sheath and ironing out various degrees of memory curve in the distal tip of the catheter. The spring ~V~ prongl49 when squeezed together r~er~ freely-through the slot whose border is~straight~inferiorly bùt serrated superiorly 1 ~, .-3i~ 7i~ j. , , "
as shown in Fig. ~lD. When rele~ the prong springs open and the ro~n~e~ segment locks in a chosen serrated position.
Distally,~a crossing slot 53 allows the prong to be pulled across to the left slot (similar in size and shape to the right slot Sl shown), thereby twisting and torquing the entire catheter'one hu"~.e~ and eighty de~Lee_ so that when the prong 49 is pulled back in the left slot position the curved configuration is ironed out, resulting in additional variations in catheter shape. The 21132~9 ~Q93/018$7 - PCT/US92/05833 locking pattern of the left slot is opposite to that of the right -- flat upper border, serrated lower border, still allowing collar loç~ing in various retracting positions.
The inner catheter proximally must exit through a valve (such as hemostasis valve 61 shown in Fig. lC) as found in current arterial sheaths. A ~Y~ branch side port 63 allows constant pressure flushing of the sheath to prevent possible clot formation and allows water activation of the hydrophilic retraction wire.
On top of the side port 63, slide tracks 6S (see Fig. lE) are molded. The tracks contain a plastic ns~ spring slide 67 with loc~ing teeth. The slide spring is attached to the pull wire 37 proximally. As the slide spring is disengaged by pushing downward and pulling back, the wire is retracted. When released the ~S~ slide locks into the celected position in the track.
When straight~ning of the enabling sheath is desired, the slide 67 is ~is~ngaged and pushed to the forward position, thereby releasing traction on the wire and allowing the enabling sheath to reform spontA-,eo!-~ly or with help by sliding the reinforced catheter towards the tip or by placing a straightening wire guide ,. ~ . . .
through the inner catheter lumen. - ~
The v~.,L~al primary curvature segment of the enabling sheath is bi A~e~ (as indicated at the reference numeral 71, Fig. lA) to curve in a desired direction by making the sidewall along the inner portion of the desired curve more flexible due to the type or thickness of the material in this segment. Similarly, a flexibility bias can be establi~e~ by dèsigning'eY~os~ or covered gaps along;~onerside of-a segment of the sheàth'over which the bend l~ desired.- When pulled distally, the more fiexible or side of the segmentrwill-give first, thereby, allowing curvature in a precisely selected segment and direction.
Alth~gh heretofore the invention has been described with ~ ~~ to a transformable catheter'with a controllablè sheath and a complex ~u~ed inner catheter, the present invention is not ~o limited. The inventive aspects of the controllable sheath are applicable in general to medical tubing, including catheters. It ~' ' ' ' j s i;J ~ ~
WO93/01857 ; PCT/US92/0583~
21132~9 - 12 -should be understood, therefore, that a reference herein to ' nsheath~ should be understood in the broader sense of medical tubing, which includes catheters.
Turning to Fig. 4A, a sheath or catheter 72 of the present invention includes a medical tube 73 having an exterior-wall and an internal lumen exten~ing substantially through the length of the tube. The tube has an outside diameter sufficiently small so that it may be inserted into the human body. The distal end 74 of tube 73 is shown in Fig. 4A.
Wire 37 runs from the proximal end of the tube to the vicinity of the distal end of the tube, and, in the same manner as described above in connection w~ith Fig. l, is connected to the tube adjacent the distal end so as to allow the distal tip of the tube to be deflected upon movement of the wire. The tube has a substantially uniform transverse cross section throughout a substantial part of its length, except for the distal tip section. The tube wall adjacent the distal end has gaps 75 77, and 79 therein on one side of the longitll~in~l axis of the catheter tube 80 as to form a predetermined region of weAk~e 71. As a ~ t, upon tension h~i ng applied to the wire the ~- . .. .
distal end of the catheter tube ~nAC in the'direction of th'e predetermined ~egion of weakness.
Al~hQ~h gaps 75, 77, and 79 can all be the same size, it is preferred that they differ in size as shown in Fig. 4A. The three gapc of Fig. 4A differ in depth, as can readily be seen. It has been found that with this construction the catheter or sheath preferentially~bends first at the gap with the'-greatest depth'' (gap 79), an~d~next at the gap with the ~?co~'''greatest dëpth'(gap 77), and f;n~ll~rat the gap with the least depth (gap 75), as shown in Fig~. 4B.- 4D, as increasing-tension is applied to wire 37. ~ -~ .
Altho~gh gaps ?5, 77 and 79 of Fig. 4 are generally crescentmoon ~r~, the p~-ent invention is not limited to any particular gap ch~re. For example, gaps 81 having'a generally ' diamond shape (Fig. 5), or gaps 83 having a comro~, arrowhead shape (Fig. 6), or any of a number of other gap shapes may also be used. Gaps shaped so that portions of the catheter tube wall on opposite sides of each gap may overlap when the catheter is formed by the wire to have its greatest curvature may be used, as may gaps shaped so that there is no overlap (although overlapping can provide a tighter curve on the distal end of the --sheath/catheter)~ Similarly, gaps shaped 80 that the distal wall portion overlaps the proximal wall portion of the gap when the catheter is formed by the wire to have its greatest curvature may be used, as may gaps shaped so that the proximal wall portion overlaps the distal wall portion of the gap.
Nor is there any rigid requirement concerning depth of gap.
Although the gaps of Fig. 4 extend through the walls of the sheath/catheter to the lumen, that is not a requirement. In Fig.
7, for example, a gap 75A is provided which terminates short of the sheath/catheter lumen. It still helps provide the desired predetermined region of weakness 7l. Also shown in Fig. 7 is a reinforcing section 85 which may, for example, be co-extruded with the sheath/catheter. This reinforcing section may be used in combination with the gaps, or by itself, to cause the distal ~nd of-the sheath/catheter to bend in the direction of region 71 when tension is applied to wire 37.
No matter what the ~re of the gap, it is preferrèd that the inner surface of the gap adjacent the lumen of the catheter be smooth.
For some applications, it may be preferred that the gaps be covered. Fig. 8 shows a layer of material 87 covering the gaps.
lt ~o~ be realized that ~he physical appearance of layer 87 in ~Fig.,8 is illustrative~only.~ The appearancè will diffèr dep~n~in~ upon how layer~87 is made. It can be for~ed by dipping, fusing, or heat shr~ ng, for example.
;Similarly, the gaps themselves may be formed in a number of different ways. They can be laser cut, water jet cut, punched, or formed by any other suitable-p~o~edu~e.
In addition,~various ways can be used to form the - predetermined region of weakness 71, either alone or in ~combination with the gaps. For example, Fig. 9 shows a region of WOg3/01857 --~ PCT/US92tO5833_ weakness 71 formed by reducing the thick~e~s of the sheath/catheter wall at the predetermined region of weAk~ecs.
Or, the predetermined region of weakness may be formed by having a portion of the wall which is chemically different from the tube wall elsewhere, or otherwise differs in some way from the rest o~
the sheath/catheter wall. This is accompli~h~A, for example, by leaching material out of the a~G~riate portion of the sheath/catheter wall to form the region of we~kness, or by using a different material in that region which is weaker than the material which makes up the rest of the sheath/catheter wall.
It should be appreciated that when gaps 75, 77 and 79 are cut into a straight sheath/catheter, and the layer 87 put over those gaps, there is the possibility that layer 87 material will bulge into the inner lumen of the sheath/catheter when the distal end is curved by application of tension to wire 37.
This bulging can be prevented if the distal end of the catheter tube is preformed into a curved ~h~re with the gaps on the inner side of the preformed curve, as shown in Fig. 10. The gaps are then in their ~rest~ position~ when the distal end of the sheath/catheter is fully ~ved. A stretchable covering .
material 87 is then A~pQcited over the gaps in this ~ el, ~reet~ position, ~o that the stretchable covering layer is substantially rel~YeA when the tube is A; SpQ~e~ in a predetermined bent position.
With this construction, the stretchable covering layer 87 is ubstantially in tension when the distal end of the sheath/catheter is straight, and the covering~layer tends to pull the distal end back tol.the preformed,-curved ~-r~ To ovërcome this ~nA~ncy,.a spring (or other suitable device) 91 is provid~d for biassing the stretchable covering layer into à stretched position, as shown in Fig. 11. A jacket of material 93 is provided to cover.the biassing spring.
Turning to Figs. 12 and 12A, it is desirable to make the transformable catheter of the p~ -ent invention as easy to use as possible~ To facilitate this, a h~nAle assembly 95 is provided which is an alternative to the structure shown in Figs. lC - lE.

r ; ~ ~

W093/01857 ~ r PCT/US92/~833 -- 15 -- .
~nAle assembly 95 includes a h~nAle 97 fixedly ~ecured to sheath 33 . ~n~l e 97 has a slot 99 formed therein in which rides a thumbwheel operated clamp 101 (shown in more detail in Fig.
12A). The body of the thumbwheel operated clamp is connected to wire 37, 80 that the user may manually adjust the tension on wire 37 by moving clamp 101 to the desired position in slot 99 and fix the clamp in that position to maintain the desired tension on the wire. Since the position of clamp 101 in slot 99 is infinitely variable, the tension on wire 37 is also continuously variable over the desired range.
~he construction of Fig. 12 al~o provides for infinite -variation in the rotational and longi~A i n- 1 positioning of catheter 35 with t ~ ~ ~L to h~nAl e 97 - The hanAle has secured thereto a spring clamp 103. Catheter 35 may be held by the jaws of spring clamp 103 (or other suitable device) in any desired rotational or longit~ n~l position, as controlled by the user.
The jaws of the clamp are merely opened to allow the user to move the catheter longi~ inally and/or rotationally, and then closed on the catheter to hold it in the new desired position.
A180 shown in Fig. 12 i8 an A--Y~ 1 i a~y line 105 which constitutes means (in combination with a syringe, for example) -for forcing fluid between the sheath 33 and the catheter 35.
.- . , .
- Such fl~ ng helps to p~evel.L the formation of clots, for example.
In view of the above, it will be seen that the various objects and fea~ s of the ~L~ ~o~t i,~en~ion are achieved and ~ other adv~ntAgeous ~ ts obtained. m e examples of the present }on ~i~clo~ed herein~are intended to be illustrative, and are not to be~construed in a limiting ~en~e.
. -- . .
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.
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A transformable catheter comprising:
a sheath having a diameter sufficiently small so that the sheath may be inserted into the human body, said sheath having a length which is a substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath, the distal end of the sheath being curvable to a plurality of different curvatures;
a preformed inner catheter having a curve formed into the distal end thereof, said preformed catheter being sized to fit in the sheath bore and being axially movable with respect to the sheath in the bore, said sheath being sufficiently rigid and the inner catheter being sufficiently pliable so that withdrawal of the inner catheter into the sheath substantially irons out the curve of that portion of the distal tip which is disposed in the sheath, said distal tip resuming its curved shape upon movement thereof completely out of the sheath bore, said inner catheter having a length substantially corresponding to the length of the transformable catheter;
means for curving the distal end of the sheath to a selected one of the plurality of different sheath curvatures;
whereby by suitable manipulation of the curving means and of the inner catheter with respect to the sheath the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user.

2. The transformable catheter as set forth in claim 1 wherein the sheath includes at its distal end a predetermined direction of curvature so that upon operation of the curving means the distal end of the sheath bends in the predetermined direction of curvature.

3. The transformable catheter as set forth in claim 1 wherein the distal tip of the inner catheter is substantially more pliable than the body of the inner catheter, whereby the inner catheter has sufficient strength to support axial and rotational movement thereof with respect to the sheath.

4. The transformable catheter as set forth in claim 1 further including means for holding the inner catheter longitudinally in place with respect to the sheath at a plurality of positions.

5. The transformable catheter as set forth in claim 1 further including means for rotating the inner catheter with respect to the sheath to allow formation of different catheter shapes at different rotational positions of the inner catheter.

6. The transformable catheter as set forth in claim 1 wherein the sheath includes a lumen extending substantially from the proximal to the distal end thereof in which the curving means is disposed.

7. A transformable catheter comprising:
a sheath having a straight relaxed shape and having a diameter sufficiently small so that the sheath may be inserted into the human body, said sheath having a length which is a substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath;
a preformed inner catheter having a complex curve formed into the distal end thereof, said preformed catheter being sized to fit in the sheath bore and being axially movable with respect to the sheath in the bore, said sheath being sufficiently rigid and the inner catheter being sufficiently pliable so that withdrawal of the inner catheter into the sheath substantially irons out the curve of that portion of the distal tip which is disposed in the sheath, said distal tip resuming its complex curve shape upon movement thereof completely out of the sheath bore, said inner catheter having a length substantially corresponding to the length of the transformable catheter, said complex curve having at least three curve portions having different radii of curvature, at least one of said curve portions having a direction of curvature retrograde to that of at least two of the other curve portions;
at least one wire running from the proximal end of the sheath to the vicinity of the distal end of the sheath, said wire being connected to the sheath adjacent the distal end so as to allow the distal tip of the sheath to be deflected from the straight relaxed shape upon movement of said wire;
whereby by suitable manipulation of the wire and of the inner catheter with respect to the sheath the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user.

8. The transformable catheter as set forth in claim 7 wherein the sheath includes at its distal end a predetermined region of weakness so that upon tension being applied to the wire, the distal end of the sheath bends in the direction of the predetermined region of weakness.

9. The transformable catheter as set forth in claim 8 wherein upon removal of the tension from the wire, the sheath returns to its original straight relaxed shape.

10. The transformable catheter as set forth in claim 7 wherein the distal tip of the inner catheter is substantially more pliable than the body of the inner catheter, whereby the inner catheter has sufficient strength to support axial and rotational movement thereof with respect to the sheath.

11. The transformable catheter as set form in claim 7 further including means for holding the inner catheter longitudinally in place with respect to the sheath at a plurality of positions.

12. The transformable catheter as set forth in claim 7 further including means for rotating the inner catheter with respect to the sheath to allow formation of different catheter shapes at different rotational positions of the inner catheter.

13. The transformable catheter as set forth in claim 7 wherein the sheath includes a lumen extending substantially from the proximal to the distal end thereof in which the wire is disposed.

14. The transformable catheter as set forth in claim 7 wherein there is only one wire running from the proximal end of the sheath to the vicinity of the distal end of the sheath.

15. A transformable catheter comprising:
a sheath having a diameter sufficiently small so that the sheath may be inserted into the human body, said sheath having a length which is a substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath;
a preformed inner catheter having a curve formed into the distal end thereof, said preformed catheter being sized to fit in the sheath bore and being axially movable with respect to the sheath in the bore, said sheath being sufficiently rigid and the inner catheter being sufficiently pliable so that withdrawal of the inner catheter into the sheath substantially irons out the curve of that portion of the distal tip which is disposed in the sheath, said distal tip resuming its curved shape upon movement thereof completely out of the sheath bore, said inner catheter having a length substantially corresponding to the length of the transformable catheter;
means for deflecting the distal tip of the sheath;
whereby by suitable manipulation of the deflecting means and of the inner catheter with respect to the sheath the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user;
means for holding the inner catheter longitudinally in place with respect to the sheath at a plurality of positions;
wherein the means for holding the inner catheter longitudinally in place with respect to the sheath at a plurality of positions includes means for mechanically locking the inner catheter in place with respect to the sheath, said means for mechanically locking being manually operable to unlock the inner catheter with respect to the sheath for longitudinal movement with respect thereto.

16. A transformable catheter comprising:
a sheath having a diameter sufficiently small so that the sheath may be inserted into the human body, said sheath having a length which is a substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath;
a preformed inner catheter having a curve formed into the distal end thereof, said preformed catheter being sized to fit in the sheath bore and being axially movable with respect to the sheath in the bore, said sheath being sufficiently rigid and the inner catheter being sufficiently pliable so that withdrawal of the inner catheter into the sheath substantially irons out the curve of that portion of the distal tip which is disposed in the sheath, said distal tip resuming its curved shape upon movement thereof completely out of the sheath bore, said inner catheter having a length substantially corresponding to the length of the transformable catheter;
means for deflecting the distal end of the sheath;
whereby by suitable manipulation of the deflecting means and of the inner catheter with respect to the sheath the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user;
further including mechanical means for locking the inner catheter in at least two different rotational positions with respect to the sheath, said mechanical means for locking being manually operable for unlocking the inner catheter with respect to the sheath for movement to another rotational position with respect thereto.

17. A transformable catheter comprising;
a sheath having a diameter sufficiently small so that the sheath may be inserted into blood vessels of the human body, said sheath having a length which is a substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath;
a preformed inner catheter having a curve formed into the distal end thereof, said preformed catheter being sized to fit in the sheath bore and being axially and rotationally movable with respect to the sheath in the bore, said sheath being sufficiently rigid and the inner catheter being sufficiently pliable so that withdrawal of the inner catheter into the sheath substantially straightens out the portion of the curve of the distal tip disposed within the sheath, said distal tip resuming its curved shape upon movement thereof out of the sheath bore, said inner catheter having a length substantially corresponding to the length of the transformable catheter;
means for deflecting the distal end of the sheath;

whereby by suitable manipulation of the deflecting means and of the inner catheter with respect to the sheath, the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user; and a spring disposed about the distal end of the sheath.

18. The transformable catheter as set forth in claim 17 further including a jacket of material covering said spring.

19. A transformable catheter comprising:
a substantially straight sheath having a diameter sufficiently small so that the sheath may be inserted into the human body, said sheath having a length which is substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath;
a preformed inner catheter having a complex curve formed into the distal end thereof, said preformed catheter being sized to fit in the sheath bore and being axially movable with respect to the sheath in the bore, said sheath being sufficiently rigid and the inner catheter being sufficiently pliable so that withdrawal of the inner catheter into the sheath substantially irons out the curve of that portion of the distal tip which is disposed in the sheath, said distal tip resuming its complex curve shape upon movement thereof completely out of the sheath bore, said inner catheter having a length substantially corresponding to the length of the transformable catheter, said complex curve having at least three curve portions having different radii of curvature, at least one of said curve portions having a direction of curvature, at least one of said curve portions having a direction of curvature retrograde to that of at least two of the other curve portions;
at least one wire running from the proximal end of the sheath to the vicinity of the distal end of the sheath, said wire being connected to the sheath adjacent the distal end so as to allow the distal tip of the sheath to be deflected upon movement of said wire;

whereby by suitable manipulation of the wire and of the inner catheter with respect to the sheath the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user;
means for holding the inner catheter longitudinally in place with respect to the sheath at a plurality of positions;
wherein the means for holding the inner catheter longitudinally in place with respect to the sheath at a plurality of positions includes means for mechanically locking the inner catheter in place with respect to the sheath, said means for mechanically locking being manually operable to unlock the inner catheter with respect to the sheath for longitudinally movement with respect thereto.

20. The transformable catheter as set forth in claim 19 wherein the means for mechanically locking includes a slot and pin locking mechanism.

21. A transformable catheter comprising:
a substantially straight sheath having a diameter sufficiently small so that the sheath may be inserted into the human body, said sheath having a length which is a substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath;
a preformed inner catheter having a complex curve formed into the distal end thereof, said preformed catheter being sized to fit in the sheath bore and being axially movable with respect to the sheath in the bore, said sheath being sufficiently rigid and the inner catheter being sufficiently pliable so that withdrawal of the inner catheter into the sheath substantially irons out the curve of that portion of the distal tip which is disposed in the sheath, said distal tip resuming its complex curve shape upon movement thereof completely out of the sheath bore, said inner catheter having a length substantially corresponding to the length of the transformable catheter, said complex curve having at least three curve portions having different radii of curvature, at least one of said curve portions having a direction of curvature retrograde to that of at least two of the other curve portions;
at least one wire running from the proximal end of the sheath to the vicinity of the distal end of the sheath, said wire being connected to the sheath adjacent the distal end so as to allow the distal tip of the sheath to be deflected upon movement of said wire;
whereby by suitable manipulation of the wire and of the inner catheter with respect to the sheath the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user;
further including mechanical means for locking the inner catheter in at least two different rotational positions with respect to the sheath, said mechanical means for locking being manually operable for unlocking the inner catheter with respect to the sheath for movement to another rotational position with respect thereto.

22. A method of directing and shaping an inner curved surgical element by interaction with a curvable outer catheter tube in which the inner curved element is disposed, said outer catheter tube having a diameter sufficiently small so that the catheter tube may be inserted into the human body, having a length substantially the length of the inner element, and having a bore therethrough running substantially from the proximal end of the catheter tube to the distal end of the catheter tube, said inner curved element being disposed in said bore and being axially movable with respect to the catheter tube in the bore, said catheter tube being sufficiently rigid and the inner element being sufficiently pliable so that withdrawal of the inner element into the catheter tube substantially irons out the portion of the curve of the distal tip of the inner element disposed within the catheter tube, said distal tip resuming its curved shape upon movement thereof out of the catheter tube bore, said inner element being longer than the length of the catheter tube, the distal end of the catheter tube being curvable in a predetermined direction, said method comprising the steps of:
disposing the inner element at a first rotational position with respect to the predetermined direction of curvature of the catheter tube such that the distal end of the inner element is disposed substantially in a plane containing the longitudinal axis of the predetermined direction of curvature, and extending the inner element distally outwardly with respect to the catheter tube to generate the desired element shape;
disposing the inner element at a second rotational position with respect to the predetermined direction of curvature of the catheter tube, said second rotational position being substantially 180 degrees from the first rotational position, and extending the inner element distally outwardly with respect to the catheter tube to generate the desired element shape; and disposing the inner element at a third rotational position with respect to the predetermined direction of curvature of the catheter tube, said third rotational position being disposed intermediate the first and second rotational positions, and extending the inner element distally outwardly with respect to the catheter tube to generate the desired element shape.

23. The method as set form in claim 22 wherein said catheter tube also has at least one wire running from the proximal end of the catheter tube to the vicinity of the distal end of the catheter tube, said wire being connected to the catheter tube adjacent the distal end such that the distal tip of the catheter tube is deflected upon tension being applied to said wire to modify the shape of the inner element carried by the catheter tube, further including the step of applying tension to said wire to deflect the distal end of the catheter tube an amount sufficient to form the inner element into a desired shape.

24. A combination catheter comprising:
a catheter tube having a wall and an internal lumen extending substantially through the length of the catheter tube, said catheter tube having an outside diameter sufficiently small so that the catheter tube may be inserted into the human body, said catheter tube having a proximal end and a distal end, said catheter tube further having a deflectable distal tip controlled from said proximal end;
said catheter tube having a substantially uniform transverse cross section throughout a substantial part of its length, the catheter tube wall adjacent the distal end of the catheter tube having a predetermined rotational reference position on one side of the longitudinal axis of the catheter tube;
an inner surgical element disposed in the lumen of the catheter tube, said inner surgical element being rotationally and axially movable in the lumen of the catheter tube, said inner surgical element being sufficiently pliable to bend upon bending of the catheter tube; and manually operable means for fixing the inner surgical element in desired rotational positions with respect to the catheter tube.

25. The catheter as set forth in claim 24 further including manually operable means for fixing the inner surgical element in desired longitudinal positions with respect to the catheter tube.

26. The catheter as set forth in claim 25 wherein the inner surgical element has a curved distal end.

27. The catheter as set forth in claim 24 wherein the catheter tube wall thickness is reduced at the predetermined rotational reference position.

28. The catheter as set forth in claim 24 wherein the catheter tube wall at the predetermined rotational reference position is defined by a material which differs from that of the rest of the catheter tube wall.

29. The catheter as set forth in claim 28 wherein the catheter tube wall at the predetermined rotational reference position is defined by a material which is weaker than the material forming the opposing wall of the catheter tube wall.

The catheter as set forth in claim 24 wherein the distal end of the catheter tube is preformed into a curved shape.

31. The catheter as set forth in claim 29 wherein said weaker material includes at least one gap in the catheter wall.

32. The catheter as set forth in claim 31 wherein said gaps are covered by a stretchable covering layer, said stretchable covering layer being substantially relaxed when the catheter tube is disposed in a predetermined bent position.

33. The catheter as set forth in claim 32 wherein said stretchable covering layer disposed over said gaps is substantially in tension when the distal end of the catheter tube is substantially straight.

34. The catheter as set forth in claim 32 further including means for biasing the stretchable covering layer into a stretched position.

35. A transformable catheter comprising:
a sheath having a diameter sufficiently small so that the sheath may be inserted into blood vessels of the human body, said sheath having a length which is a substantial fraction of the entire length of the transformable catheter, and having a bore therethrough running substantially from the proximal end of the sheath to the distal end of the sheath, said sheath having a deflectable distal tip controlled from said proximal end;
a preformed inner catheter sized to fit in the sheath bore and being axially and rotationally movable with respect to the sheath in the bore;
whereby by suitable manipulation of the inner catheter with respect to the sheath and of the distal end of the sheath the shape of the exposed portion of the distal end of the inner catheter may be reformed and transformed to any of a variety of shapes as desired by the user; and manually operable means for fixing the catheter in any desired rotational and/or longitudinal position with respect to the sheath.

36. The transformable catheter as set forth in claim 35 wherein the sheath wall adjacent the distal end of the sheath has gaps therein on one side of the longitudinal axis of the sheath so as to form a predetermined region of weakness, whereby the distal end of the sheath preferentially deflects in the direction of the predetermined region of weakness, further including a layer of material covering said gaps which form the predetermined region of weakness.

37. The transformable catheter as set forth in claim 36 wherein the predetermined rotational reference position is defined by gaps in the sheath wall which are not all of the same size.

38. The transformable catheter as set forth in claim 37 wherein the gaps differ in depth, whereby the sheath preferentially bends first at the gap with the greatest depth, and next at the gap with the second greatest depth.

39. The transformable catheter as set forth in claim 35 wherein the means for fixing the catheter in position with respect to the sheath includes a manually operable clamp, said manually operable clamp being adapted to hold the catheter against both longitudinal and rotational movement with respect to the handle.

40. A combination catheter comprising:
a catheter tube having a wall and an internal lumen extending substantially through the length of the catheter tube, said catheter tube having an outside diameter sufficiently small so that the catheter tube may be inserted into the human body, said catheter tube having a proximal end and a distal end, said catheter tube further having a deflectable distal tip controlled from said proximal end, said deflectable distal tip having a preformed shape;
a spring disposed around the inner lumen of the distal tip of the catheter tube such that the spring tends to restore the distal tip to its preformed shape;
an inner surgical element disposed in the lumen of the catheter tube, said inner surgical element being movable in the lumen of the catheter tube, said inner surgical element being sufficiently pliable to bend upon bending of the catheter tube.

41. The combination catheter as set forth in claim 40 wherein the spring is disposed in the wall of the catheter tube.

42. A method of changing the shape of a catheter located in a human body, said catheter comprising a combination catheter having a sheath with a length which is a substantial fraction of the entire length of the combination catheter, said combination catheter also having a preformed inner catheter with a curve formed into the distal end thereof disposed in the bore of the sheath, said preformed inner catheter extending distally from the distal end of the sheath, said method comprising the steps of:
axially moving the inner catheter to a first longitudinal position with respect to the sheath to expose only so much of the distal end of the inner catheter as to cause the exposed portion of the distal end of the inner catheter to take a first desired shape, wherein the distal end of the inner catheter can take a plurality of shapes depending upon the amount of the distal end which is exposed;
mechanically holding the inner catheter against longitudinal movement in the first longitudinal position;
releasing the inner catheter and axially moving the inner catheter with respect to the sheath to a second longitudinal position to cause the exposed portion of the distal end of the inner catheter to take a second desired shape;
mechanically holding the inner catheter against longitudinal movement in the second longitudinal position; and deflecting the distal end of the sheath to direct the distal end of the inner catheter in any of a plurality of desired directions and to modify at least one of the first and second shapes.

43. The method as set forth in claim 42 wherein the shape of the distal end of the inner catheter is affected by contact with the wall of the cavity in which the catheter is disposed.

44. The method as set forth in claim 42 wherein the deflecting step includes first deflecting the distal end of the sheath in a direction such that the preformed curve of the distal end of the inner catheter may be reformed and then further extending the distal end of the inner catheter distally out of the sheath to reform the curve of the distal end of the inner catheter.

45. The method as set forth in claim 42 wherein the distal end of the sheath is deflected and the distal tip of the inner catheter is exposed in an amount to cause the distal end of the combination catheter to assume a radius smaller than the radius achievable by deflecting the distal end of the sheath alone.

46. The method as set forth in claim 42 wherein the distal end of the sheath is deflected by selectively applying tension to a wire disposed in the sheath.

47. A method of changing the shape of a catheter located in a human body, said catheter comprising a combination catheter having a sheath with a length which is a substantial fraction of the entire length of the combination catheter, said combination catheter also having a preformed inner catheter with a curve formed into the distal end thereof disposed in the bore of the sheath, said preformed inner catheter extending distally from the distal end of the sheath, said method comprising the steps of:
rotating the inner catheter with respect to the sheath to a first rotational position with respect to the sheath;
mechanically holding the inner catheter against rotational movement in the first rotational position;
releasing the inner catheter and rotationally moving the inner catheter with respect to the sheath to a second rotational position;
mechanically holding the inner catheter against rotational movement in the second rotational position; and deflecting the distal end of the sheath to modify the shape of the combination catheter while the inner catheter is in at least one of the first and second rotational positions, whereby different catheter shapes are formed at different rotational positions of the inner catheter.

48. A method of changing the shape of a catheter located in a human body, said catheter comprising a combination catheter having a sheath with a length which is a substantial fraction of the entire length of the combination catheter, said combination catheter also having a preformed inner catheter with a curve formed into the distal end thereof disposed in the bore of the sheath, said preformed inner catheter extending distally from the distal end of the sheath, said method comprising the steps of:
axially moving the inner catheter with respect to the bore to expose only so much of the distal end of the inner catheter as to cause the exposed portion of the distal end of the inner catheter to take a desired shape, wherein the distal end of the inner catheter can take a plurality of shapes depending upon the amount of the distal end which is exposed;
mechanically fixing the inner catheter in place with respect to the sheath when a desired shape is achieved; and deflecting the distal end of the sheath to modify the achieved shape.