Patent Publication Number: US-6669665-B2

Title: Delivery mechanism for balloons, drugs, stents and other physical/mechanical agents and method of use

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of patent application Ser. No. 09/305,138 filed May 4, 1999, now U.S. Pat. No. 6,312,406 B1, which is a continuation-in-part of prior patent application Ser. No. 08/932,726 filed Sep. 18, 1997, now U.S. Pat. No. 6,056,722. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to catheters for delivering balloons, drugs, stents, and other devices or agents into the arterial or venal systems of the human body. In particular, this invention relates to catheters that provide a quick, efficient and rapid exchange capability for the delivery of an angioplasty balloon into the arterial vessels of the human heart. 
     BACKGROUND ART 
     The human body includes arterial and venous conduits which run throughout various sections of the human body. These conduits conduct blood into and from the heart which maintain the circulation that helps to sustain the metabolic events in the body. The vessels undergo biological, physiological and mechanical changes depending on the body metabolism which determine the functionality of the wall of the artery. 
     Sometimes the wall of an artery becomes occluded due to deposits of fatty tissues which in turn form plaque on the walls of the artery. These plaques then have to removed to restore the normal function of the artery. One known mechanism of removing the plaque is to compress the plaque against the wall of the artery using a balloon catheter. This procedure is called Per cutaneous (under the skin) Transluminal (under x-ray guidance) Coronary (region of intervention) Angioplasty (plaque compression) or PTCA. 
     For a PTCA procedure to be accomplished, a balloon catheter and a guidewire along with a guiding catheter are typically required. The guiding catheter is normally introduced in a groin artery and pushed upwards towards the aorta until it reaches the mouth of the coronary artery. Once the guiding catheter is placed at the opening of the coronary artery, a highly floppy wire is introduced into the guiding catheter such that the wire crosses the mouth of the guiding catheter and goes into the coronary artery. It then has to reach the site of the lesion (plaque) which is usually a very tortuous route and the operator (the cardiologist) has to struggle to reach the guidewire in place. Once a guidewire has crossed the lesion, it is then pushed distally to the lesion so that it remains at a safe place. This is to ensure that the wire does not slip out of the lesion. 
     A catheter which has a balloon at one end and a shaft at the other end is usually introduced into the lesion on top of the guidewire. Although the mechanism of introduction and the design of the catheter that facilitate the mechanism have been improved by known catheters, they still leave room for improvement. 
     Several designs of balloon catheters are disclosed in various U.S. patents that facilitate insertion into the artery using a guidewire as an intermediate tool. The way in which the balloon travels on top of the guidewire and the length of the catheter that travels on top of the guidewire is the subject of known devices such as those shown and described in U.S. Pat. Nos. 5,620,417; 5,607,406; 5,607,394; 5,598,844; 5,549,556; 5,545,134; 5,531,690; 5,514,092; 5,077,311; 5,501,227; 5,489,271; 5,472,425; 5,468,225; 5,460,185; 5,458,613; 5,443,457; 5,413,560; 5,413,559; 5,409,097; 5,387,226; 5,383,853; 5,380,283; 5,357,978; 5,336,184; 5,334,147; 5,195,978; 5,170,286; 4,748,982; 4,762,129; and 5,626,600, all of which are incorporated herein in their entirety. 
     While each one of these above-listed patents describe and illustrate several ways of approaching the traverse mechanism, all of them essentially assume the following; (1) the catheter has proximal and distal ends; (2) there is a balloon mounted on the distal end; (3) the proximal end has a shaft; (4) the interior of the balloon is in communication with a lumen; (5) there is another sleeve that either extends towards the entire length of the catheter or runs at a fixed distance from the distal end of the catheter; (6) the sleeve if it does not run the entire length of the catheter extends up to a predetermined distance from the balloon up to the midsection of ⅓ of the entire catheter length or sometimes shorter; (7) the portion of the sleeve is called the flexible portion, while the proximal portion is either a hallow tube or an elliptical structure which provides for pushability of the catheter; (8) the sleeve has one opening at the proximal side of the balloon through which a guidewire can be inserted and it comes out through the center of the balloon—this is commercially known as the rapid exchange or the monorail concept; (9) in instances where the sleeve extends along the entire length of the balloon the wire extends inside the sleeve from the distal to the proximal end of the catheter through the balloon—this is called the over the wire concept. 
     In the devices of the above patents, regardless of whether the catheter is over the wire or monorail, the guidewire has one entry point and one exit point and the regions between the entry and exit are imbedded in the catheter sleeve or the catheter shaft. 
     However, the catheters of the above patents have some serious disadvantages in lesions that are completely occluded or in lesions that have severe tortuosity. In lesions that have complex distal diseases the catheter has to traverse multiple bifurcations in order to reach the site of lesion. In case of the above described known catheters, the operator or the cardiologist forces the body of the catheter on top of the wire using an external force. This force then transmits from the catheter body to the surface of the wire. When the wire is held with a counteractive force, the force against the catheter becomes greater and a law of physics comes into play, the object with the greatest force moves forward. 
     In balloon angioplasty, it is desired to design a catheter which pushes on top of a wire with a minimum force. In order to achieve this, catheters with very low profiles are sought. These low profiles enable easy slippage on top of the wire. Sometimes the wires are also coated with a lubricous coating to enable ease of passage of the catheter. 
     In numerous instances, the operator is unable to cross a lesion with a rapid exchange catheter. He then switches over to an over the wire design or vice versa when the operator cannot transmit the necessary force for the balloon catheter to traverse the lesion. 
     In general rapid exchange catheter designs are preferred because there is only about ⅓ of the catheter body that is imbedded in the guidewire and hence the force required for the catheter to travel is less. In the case of total occlusions, over the wire designs are preferred as the catheter. If the catheter is being pushed through a very hard plaque or a totally occluded artery, the maximum force from the proximal end of the catheter has been delivered to the distal end. 
     The force delivered at the proximal end by the operator relates to the force of balloon moving forward toward the lesion. There are forces lost between the proximal end to the distal end of the catheter and this happens due to the tortuosity of the lesions, length of the shaft of the catheter and also lesion morphology. 
     Prior art inventions are easily understood if we draw a very simple analogy between the catheter and the guidewire. Assume the guidewire is the track of the train, and the catheter is the train. In the rapid exchange design, the train has one pair of small wheels that are the distal ⅓ of the catheter of the length of the sleeve. In the case of an over the wire design, the train has one pair of long wheels from the distal end of the catheter to the proximal end. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a catheter comprising body member having a lumen; balloon member disposed on the body member and communicating with the lumen; and plurality of sleeve members disposed on the body member, each sleeve member having a passageway therethrough. 
     In one preferred embodiment, at least one of the sleeve members is disposed in a distal region of the elongated member. The at least one of the sleeve members can be disposed adjacent the balloon member and can have a length less than that of the balloon member. The at least one of the sleeve members can be disposed within the balloon member. 
     According to a catheter of the present invention, at least one of the sleeve members can be disposed adjacent the balloon member and have a length greater than that of the balloon member. The at least one of the sleeve members extends through the balloon member. 
     In another preferred embodiment, the at least one of the sleeve members can be disposed generally centrally of the balloon member. 
     In alternative embodiments, the at least one of the members can be disposed generally eccentrically of the balloon member, or generally outside of the balloon member, or proximally of the balloon member. The remaining sleeve members can be equally sized and equally spaced along the catheter body. Alternatively, the remaining sleeve members can be differently sized and differently spaced along the catheter body. Preferably there are two or three remaining sleeve members. 
     The present invention is also directed to an angioplasty catheter comprising elongated body member having a lumen which includes an opening adjacent its distal end and at least one opening adjacent its proximal end; balloon member sealingly disposed on the elongated member adjacent its distal end, the elongated member having at least one opening communicating with the interior of the balloon and the lumen within the elongated body member; and plurality of sleeve members disposed on the elongated member, each sleeve member having a passageway therethrough. 
     An angioplasty catheter, according to the present invention, can also comprise guidewire dimensioned and configured for passing through the passageway of the sleeve members. 
     The present invention is also directed to a catheter comprising body member having a lumen; and plurality of sleeve members disposed on the body member, each sleeve member having a passageway therethrough. 
     A catheter, according to the present invention, comprises generally rigid body member having a lumen; balloon member disposed on the body member and communicating with said lumen; and plurality of generally flexible sleeve members disposed on the body member, each sleeve member having a passageway therethrough. 
     The present invention also is directed to a catheter which comprises body member having a lumen; device member disposed on the body member; and plurality of sleeve members disposed on the body member, each sleeve member having a passageway therethrough. The device member can be a stent or a container having a chamber for containing a drug. 
     Also, the present invention is directed to a method of using a catheter comprising providing a catheter including body member having a lumen; balloon member disposed on the body member and communicating with the lumen; and plurality of sleeve members disposed on the body member, each sleeve member having a passageway therethrough; selectively passing a guidewire through the passageways of the sleeve members, the guidewire being disposed in a body cavity, so as to position the catheter at a desired location within the body cavity; and selectively inflating the balloon and withdrawing the catheter from within the body cavity. 
     The present invention is also directed to a method of using a catheter comprising providing a catheter including body member having a lumen; device member disposed on the body member; and plurality of sleeve members disposed on the body member, each sleeve member having a passageway therethrough; selectively passing a guidewire through the passageways of the sleeve members, the guidewire being disposed in a body cavity, so as to position the catheter at a desired location within the body cavity; and selectively operating the device member within the body cavity. 
     According to one preferred embodiment wherein the device member comprises a container having a chamber containing a drug, the method further comprises releasing the drug from the chamber. Alternatively, wherein the device member comprises a stent, the method further comprises releasing the stent within the body cavity. 
     The present invention is also directed to a catheter comprising body member having a lumen; balloon member disposed on said body member and communicating with the lumen; and plurality of sleeve members disposed on the body member, each sleeve member having a passageway therethrough, at least one or more sleeve members disposed adjacent the balloon member and along at least a portion of the length of the balloon member, and wherein the balloon adjacent sleeve members have a generally non uniform cross-section. In a preferred embodiment, at least one of said balloon adjacent sleeve members is generally conical and has a cross-section generally increasing in the proximal direction. Also, at least one of the sleeve members is disposed in a distal region of said elongated member. In addition, at least one of the sleeve members is disposed adjacent the balloon member and has a length less than that of the balloon member. Furthermore, at least one of the sleeve members can be disposed within the balloon member. At least one of the sleeve members is disposed adjacent the balloon member and has a length greater than that of the balloon member. At least one of the sleeve members extends through the balloon member. 
     At least one of the sleeve members can be disposed in one of following configurations, i.e., generally centrally, eccentrically, generally outside, or proximally of the balloon member. The remaining sleeve members can be equally sized and equally spaced along the catheter body. Also they can be differently sized and differently spaced along the catheter body. In preferred embodiments, there are two or three remaining sleeve members. The body member can have a plurality of apertures on said body member. 
     Also the present invention can be directed to an angioplasty catheter comprising elongated body member having a lumen and having an opening at its proximal end and at least one opening adjacent its distal end; elongated balloon member sealingly disposed on the elongated body member adjacent its distal end, the elongated body member having at least one opening communicating with the interior of the balloon and the lumen within the elongated body member; plurality of sleeve members disposed on the elongated member, each sleeve member having a passageway therethrough, at least one or more sleeve members disposed adjacent the balloon member and along at least a portion of the length of the balloon member, and wherein the balloon adjacent sleeve members have a generally non uniform cross-section; and guidewire dimensioned and configured for passing through the passageway of the sleeve members. 
     Method of using a catheter comprises providing a catheter comprising: body member having a lumen; balloon member disposed on the body member and communicating with the lumen; and plurality of sleeve members disposed on the body member, each sleeve member having a passageway therethrough, at least one or more sleeve members disposed adjacent the balloon member and along at least a portion of the length of the balloon member, and wherein the balloon adjacent sleeve members have a generally non uniform cross-section; selectively passing a guidewire through the passageways of the sleeve members, the guidewire being disposed in a body cavity, so as to position the catheter at a desired location within the body cavity; and selectively inflating the balloon. At least one of the balloon adjacent sleeve members is generally conical and is provided with a cross-section that is generally increasing in the proximal direction. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is described in detail below with reference to the drawings wherein: 
     FIG. 1A is a cross-sectional view of a balloon catheter according to the prior art taken along the midsection of the balloon, wherein the balloon lumen is in the center and the guidewire lumen is eccentric to the balloon but in the shaft of the catheter. 
     FIG. 1B is a cross-sectional view of a balloon catheter according to the prior art wherein the balloon lumen is in the center and the guidewire lumen is eccentric to the shaft. 
     FIG. 1C is a cross-sectional view of a bi-lumen catheter according to the prior art wherein the guidewire lumen and the balloon lumen are concentric to the shaft of the catheter. 
     FIG. 1D is a cross-sectional view of the balloon catheter according to the prior art wherein the guidewire lumen and the balloon lumen are in a symmetrical axis to each other. 
     FIG. 2A is a side view of a balloon catheter according to the prior art wherein the guidewire sleeve exits proximally out of the balloon about ⅔ the length of the catheter. 
     FIG. 2B is a side view of a balloon catheter according to the prior art wherein the guidewire sleeve exits at the proximal tip of the balloon. 
     FIG. 2C is a side view of a balloon catheter according to the prior art wherein the guidewire sleeve exits adjacent but prior to the proximal end of the catheter. 
     FIG. 2D is a side view of another embodiment of a balloon catheter according to the prior art wherein the guidewire sleeve exits at the proximal end of the catheter. 
     FIG. 3A is a side view of an embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of four spaced apart sleeve members and wherein the sleeve member through the balloon is the longest. 
     FIG. 3B is a side view of another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of four spaced apart sleeve members wherein the guidewires lumen is eccentric to the balloon lumen and exits proximal to the balloon. 
     FIG. 3C is a side view of an yet another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of four spaced apart sleeve members which are more closely spaced than the sleeve members in FIG. 3A or  3 B. 
     FIG. 3D is a side view of an still another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of three spaced apart sleeve members and wherein the sleeve member through the balloon is the longest. 
     FIG. 3E is a side view of an still yet another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of five different sized and differently spaced apart guidewire sleeve members. 
     FIG. 4A is a side view of an embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of three spaced apart sleeve lumens located along and extending beyond the ends of the balloon and wherein the guidewire lumen is eccentric to the balloon. 
     FIG. 4B is a side view of an embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of three spaced apart sleeve lumens and wherein two sleeve lumens are positioned distally of the balloon and the remaining sleeve lumen is positioned in the region of the balloon and wherein the guidewire lumen is eccentric to the balloon. 
     FIG. 4C is a side view of an yet another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of three spaced apart sleeve lumens positioned distally of the balloon and wherein the guidewire lumen is eccentric to the balloon. 
     FIG. 5 is a side view of still yet another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of three spaced apart sleeve lumens positioned proximally of the balloon. 
     FIG. 6 is a side view of an embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of four spaced apart sleeve members and wherein the sleeve member through the balloon is the longest. 
     FIG. 7 is a side view of a generally rigid tube for use with the balloon catheter of FIG.  8 . 
     FIG. 8 is a side view of an yet another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of two spaced apart sleeve members and wherein the balloon is disposed on a flexible sheath which is coupled to the generally rigid tube of FIG. 7 so that the flexible portion is distal and the rigid portion is proximal. 
     FIG. 9 is a side view of an still another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of two spaced apart sleeve members and the catheter shaft includes proximal and distal apertures for perfusion of blood during angioplasty. 
     FIG. 10 is a side view of an still yet another embodiment of a balloon catheter according to the present invention wherein the catheter shaft has microporous holes disposed along the shaft for drug delivery. 
     FIG. 11 is a side view of an yet another embodiment of a balloon catheter according to the present invention wherein the guidewire sleeve is formed of two spaced apart sleeve lumens and wherein the balloon carries a stent. 
     FIG. 12 is a side view of the balloon catheter of FIG. 11 having different sized sleeve members and further including a sheath on the stent for removal and inflation. 
     FIG. 13 is a side view of a drug delivery catheter in a closed configuration. 
     FIG. 14 is a side view of the drug delivery catheter of FIG. 13 in an open configuration. 
     FIG. 15 is a side view of a different embodiment of a balloon catheter according to the present invention wherein the guidewire channel inside the balloon has a different diameter along the length of the channel. 
     FIGS. 16A and 16B are a cross-sectional view of the catheter of FIG. 15 taken along the lines A—A and B—B, respectively, to illustrate the larger diameter at the proximal end portion of the guidewire lumen inside the balloon. 
     FIG. 17 is a side view of still another embodiment of a balloon catheter according to the present invention wherein the guidewire channel is parallel to the body member inside the balloon and wherein the sleeves are of varying length and spaced equidistantly. 
     FIG. 18 is a side view of still another embodiment of a balloon catheter according to the present invention wherein the guidewire channel is parallel to the body member inside the balloon and includes three sleeve members. 
     FIG. 19 is a side view of yet another embodiment of a balloon catheter according to the present invention wherein the guidewire channel is a long sleeve with slits under the balloon. 
     FIG. 20 is a side view of still another embodiment of a balloon catheter according to the present invention wherein the guidewire channel includes four sleeve members. 
     FIG. 21 is a side view of another embodiment of a balloon catheter according to the present invention wherein there is a single sleeve through the balloon and three sleeve members disposed outside of the balloon. 
     FIG. 22 is a side view of another embodiment of a balloon catheter according to the present invention wherein the guidewire lumen through the catheter is formed of three sleeve members which are integral with the lumen extending along the length of the catheter. 
     FIG. 23 is a side view of another embodiment of a balloon catheter according to the present invention wherein there is a double lumen through the balloon and a single lumen outside of the balloon and the guidewire lumen through the balloon is conical in shape, i.e., it has a larger diameter at its proximal end than at its distal end and has an increasing diameter from the distal end to the proximal end. 
     FIG. 24 is a side view of another embodiment of a balloon catheter according to the present invention wherein there is a single conical (or tapering) guidewire lumen through the balloon and which guidewire lumen has multiple sleeve members or sections inside the balloon. 
     FIG. 25 is a side view of another embodiment of a balloon catheter according to the present invention wherein there is a single conical (or tapering) guidewire lumen through the balloon and which guidewire lumen has slits that form a non continuous channel under the balloon. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the description which follows, any reference to direction or orientation is intended primarily and solely for purposes of illustration and is not intended in any way as a limitation to the scope of the present invention. Also, the particular embodiments described herein, although being preferred, are not to be considered as limiting of the present invention. 
     An invention is hereby described which applies the laws of physics and also the general principle of train on a track. A train moves on a track with multiple wheels which are positioned at equal distances form the engine. The present invention applies this principle to a catheter by having multiple entry points and exit points of a catheter body for the passage of a guidewire. 
     From physics it is known that the force required to push an object on top of another depends on the surface area of coverage and the nature of the radial coverage that enables a longitudinal force to be transmitted while the object is being pushed on top of the other object. 
     Various known balloon catheter configurations are shown in FIGS. 1A-1D and FIGS. 2A-2D. In FIG. 1A, a balloon  10  is shown with an internally and centrally positioned balloon lumen  12  and a guidewire lumen  14  which is in the shaft of the catheter but eccentric to the balloon  10 . In the catheter shown in FIG. 1B, the balloon lumen  16  is centrally located within the balloon  20  and the guidewire lumen  18  which is eccentric to the shaft and the balloon  20 . The catheter shown in FIG. 1C has a balloon  22  with internal guidewire lumen  24  and surrounding balloon lumen  26 . Both guidewire lumen  24  and balloon lumen  26  are concentric to the shaft of the catheter. In FIG. 1D, the guidewire lumen  30  and balloon lumen  34  are positioned within balloon  36  so that the balloon lumen  34  is centrally positioned and the guidewire lumen  30  is outside of the balloon lumen  34 . 
     In reference to FIG. 2A, a known catheter  38  includes a catheter body  40  with a distally positioned balloon  42 . A guidewire lumen  44  for a guidewire (not shown) extends from the distal end of the catheter but exits before the full length of the catheter  38 . In the catheter  46  of FIG. 2B, the guidewire lumen  48  extends through the balloon  50  and exits at the proximal end of the balloon  50 . In another known catheter  52  shown in FIG. 2C, the guidewire lumen  54  extends through the balloon  56  and extends closely to the proximal end of the catheter body  58 . As shown in FIG. 2D, the catheter  60  has a catheter body  62 , a balloon  64  and a guidewire lumen that extends the length of the balloon  64 . 
     Referring to FIG. 3A, a balloon catheter  100  according to the present invention has a catheter body  102  and a distal balloon  104 . Coupled to the catheter body  102  are four sleeve members including the longest member  106  that spans the balloon  104 . The other three sleeve members  108  are equal in size and spaced apart from each other and sleeve member  106 . Each sleeve member  106  and  108  has an entry port  110  which is located at the most distal end of the sleeve member and an exit port  112  located at the proximal end of the respective sleeve member. Thus the sleeve members provide multiple points of entry for the guidewire (not shown) and corresponding multiple points of exit for the guidewire. The exit port  112  for the largest sleeve member  106  is proximal to the proximal end of the balloon  104  either concentric or eccentric to the balloon  104 . Alternatively, the other ports of exit  112  can be located at various distances along the length of the catheter  100 . These ports of entry and exit can be located at various predetermined locations. Various desired predetermined configurations of displacements of the sleeve members  106  and  108  can be utilized as well as various lengths of the different sleeves. These points n run along the entire length of the catheter or can run only in the distal part of the catheter. 
     Depending on the lesion morphology and also the tortuosity of the lesion, the length of the catheter which runs on the guidewire can be selected. 
     In one preferred embodiment, a catheter can have four points, five or up to ten points of entry and five, six or up to 10 points of exit. In an alternative embodiment, the catheter can have seven to nine points of entry and seven to nine points of exit. 
     Depending on the length of the coverage of each, the exposed segments of the catheter between the sleeve members act as wheels. Hence the catheter of the present invention provides multiple wheels that guide the catheter. 
     The first point of entry is ideally located at the tip of the balloon and can run concentric to the balloon axis or can run eccentric to the balloon axis, the first point of exit is located just after the balloon or a short distance proximal to it. The second point of entry is located at a distance greater than the first point of entry and subsequent exit at second pint. The distance between the first point of exit and the second point of entry is the exposed part of the wire in the body of the catheter. This exposed part of the wire is called the “wire segment”. The distance between the second point of entry and the second point of exit is called the “catheter segment”, the wire segment and the catheter segment can alternate along the entire length of the catheter or only on the distal ⅓ of the catheter. 
     A catheter is also described wherein the first point of entry is located distal to the location of the balloon such that the wire does not pass inside the lumen of the balloon. In such a case the catheter shaft that has “wire segments” and “catheter segments” is taken at the site of the lesion, the wire pulled back such that it is proximal to the balloon and the balloon is then dilated at the site of the lesion. 
     Referring to FIG. 3B, the catheter  114 , similar to that shown in FIG. 3A, has a balloon  116  and four sleeve members  118  and  120  which are equally spaced apart. Sleeve member  118  is the longest and spans the balloon  116 . Unlike catheter  100  wherein sleeve member  106  is a separate tubular structure coupled to catheter body  102 , sleeve member  118  in catheter  114  can be formed as part of the catheter body  122 . In the alternative embodiment of FIG. 3C, the catheter  124  has four sleeve members  126  and  128  that are more closely spaced than in FIGS. 3B and 3C. 
     In yet another alternative embodiment, catheter  130  in FIG. 3D includes three sleeve member  132  and  134  which are spaced at different intervals along the catheter body  136 . Still another embodiment  138  shown in FIG. 3E has five different spaced and different sized sleeve members  140 ,  142 ,  143 ,  144  and  145 . The catheter  138  has a catheter body  146  that at its proximal end has a Y-lumen configuration  148 . 
     Turning to the catheter embodiment  150  shown in FIG. 4A, a catheter body  152  has a balloon structure  154  (shown schematically) at the distal end of the catheter  150 . Three equally sized and spaced sleeve members  156  are positioned distally and span the length of the half balloon  154 . In the alternative embodiments  158  and  160  illustrated schematically in FIGS. 4B and 4C, the balloon  154  is located on the catheter body  152  closer to the proximal end of the catheters  158  and  160 . In the embodiment  162  of FIG. 5, the balloon  164  is positioned distally of the sleeve members  166  that receive guidewire  168  that passes through the passageways of each sleeve member  166 . In the exemplary embodiment of FIG. 5, the guidewire  168  has a curled distal end  170  but straight configurations can also be employed with the catheters of the present invention. 
     Referring to FIG. 6, a catheter  172  includes a  174  and four sleeve members  176 ,  178 ,  180  and  182  which are coupled to a shaft  184  that has a larger diameter proximal end portion. FIGS. 7 and 8 illustrate two parts of balloon catheter  186  that can be combined to form the catheter. The structure of FIG. 7 is a generally rigid tube  188 . In FIG. 8, the guidewire sleeve is formed of two separate members  188  and  190  that are connected to a balloon lumen  192  that allows for inflation of balloon  194 . The balloon lumen  192  is a generally flexible sheath which can be coupled to the generally rigid tube shown in FIG.  7 . After combining the components of catheter  186 , the flexible portion is distal and the rigid portion is proximal. 
     In the embodiment of FIG. 9, the balloon catheter  196  has a guidewire sleeve that is formed of two spaced apart sleeve members  198  and  200 . Included on the catheter shaft  202  are proximal and distal apertures  204  that allow for the perfusion of blood during angioplasty. In the catheter  206  shown in FIG. 10, microporous holes  208  are provided along the length of the catheter shaft  210 . Guidewire lumens (not shown) according the present invention can be attached to the shaft  210  at various locations along the catheter body. 
     In general, each sleeve member of the various embodiments disclosed and described herein has an entry port  110  and an exit port  112  as shown and discussed in connection with the catheter  100  of FIG.  3 A. Also, each sleeve member has a passageway to accommodate the passage of the guidewire. The embodiments herein demonstrate that various sized and spaced sleeve members can be employed to allow for passage of a guidewire. Also, the guidewire lumens can be attached or coupled to the catheter shaft by various known methods of attachment. Alternatively, the guidewire lumens can be formed integrally with the catheter body. 
     The invention also covers other interventional devices apart from the balloon to include stents, mounted on balloons or otherwise, drug delivery devices where the media can be delivered distal to the balloon or proximal to the balloon. Thus the catheter of the present invention allows for improved pushability and control over that available with known catheters. The balloon can be made of compliant, semi-compliant or a non-compliant polymeric material, or a combination of a polymeric material. The body member can be made of metal, plastic or a combination of both. The sleeve member is preferably made of plastic, polymeric material. In use, the balloon can be inflated with saline or a contrast fluid as is known by those skilled in the art. 
     In the embodiment illustrated in FIG. 11, a balloon catheter  210  includes a balloon  212  disposed on a catheter shaft or balloon lumen  214  which has guidewire lumens  216  and  218 . A stent  220  is positioned on and carried by the balloon  212 . After the balloon  212  is located at the preferred or desired site within a blood vessel, the stent can be released, the balloon deflated and the catheter  210  removed. In the embodiment shown in FIG. 12, the catheter  222  also includes a sheath on the stent for removal and inflation. Different sized and positioned guidewire lumens  224  and  226  can be used with balloon  228 . Drug delivery catheters  230  are shown in FIGS. 13 and 14 which can be used with the guidewire lumens (not shown) of the present invention. In FIG. 13, the catheter  230  is shown as including a catheter shaft  232  with a distally positioned device member  234  which is shown in a closed configuration in FIG.  13  and in an open and drug released configuration in FIG.  14 . The device member  234  has a hollow chamber inside for storing a desired drug for delivery to a location within a body cavity such as a blood vessel. Alternatively, the device member  234  can store and delivery other medical devices suitably sized so that they can be carried within device member  234 . The drug within device member  234  can be discharged by saline fluid which can be injected into the device member  234  through a suitably provided lumen within catheter shaft  232 . Alternatively mechanical release systems can also be employed. 
     Yet additional alternative embodiments of the present invention are shown in FIGS. 15 through 21. In these embodiments, the guidewire channel which is attached to the body member starts distal to the balloon and terminates at a point which is just proximal to the balloon and this channel is actually a plurality of sleeves which are underlying the balloon with a gap between them. 
     The guidewire channel, which can be a plurality of sleeve members generally within the balloon, is non cylindrical and has a diameter at the distal tip of the balloon lower than at the proximal tip which is higher. Therefore, the diameter generally increases toward the proximal end of the catheter. However, such increase in diameter is not necessarily constantly increasing, however but may vary toward the non-proximal end. Therefore, for some lengths the diameter may be increasing, then constant, then increasing again and the like. Alternatively, the diameter can increase constantly toward the proximal end. Generally, the diameter may be of a non uniform cross-section. Other structural variations include: the length of the sleeve, the gap between the sleeves, the diameter to length ratio between the sleeves, and the diameter of the sleeve. 
     By way of example, the guidewire lumen generally in the middle of the balloon is not a straight (cylindrical) lumen but it is more pointed in the distal end and increases in diameter until the point at which the guidewire exits at the first exit point. The guidewire lumen passes through the balloon and terminates at a point proximal to the balloon. This lumen is actually a plurality of sleeves that are underlying within the balloon segment. This guidewire segment described above can have only two sleeves under the balloon and one of the sleeves can form a substantial length of the balloon and the other sleeve can be of a smaller length inside the balloon. There is a gap between the sleeves inside the balloon and this provides at least one differentiation of the present invention from prior devices, whereby the guidewire member is not an integral cylindrical tube attached to the body member but actually has a gap which is inside the balloon. 
     The sleeves upon termination outside the balloon can extend all the way throughout the length of the body member or can terminate proximal to the balloon. If desired, the sleeves can extend up to ¼ distance of the body member or less than ½ the distance. Alternatively, the sleeves can extend up to ½ the distance of the body member or less than ½ the distance. In another embodiment, the sleeves can extend up to ¾ the distance of the body member or less than ¾ the distance. Also, the sleeves can extend up to the full distance of the body member. When the sleeves extend beyond ½ the distance of the body member, then a hypotube shaft is not needed at the proximal end of the body member, since the extension of the sleeves can provide the support that the catheter requires. 
     The plurality of sleeves are also preferably increasing in diameter. The farther the sleeves extend the greater their diameter. The first sleeve can be of a diameter x, the second sleeve can have a slightly increasing diameter, and the third sleeve can be of slightly increasing diameter than that of the second sleeve. Preferably, the sleeve that is passing inside the balloon is of increasing diameter only. The other sleeves which form the plurality can be of constant diameter. The sleeve inside the balloon is preferably of a slightly increasing diameter. While the distal tip of the catheter could have an internal diameter of 0.015″, the end of the first sleeve proximal to the balloon could have an internal diameter of 0.016″ or even up to 0.017″. 
     The plurality of sleeves could also be of decreasing diameter, where the plurality of sleeves decrease in diameter as the number of sleeves increase. 
     The gap between the sleeves can be uniform or generally non uniform. For example, the gap between the first sleeve and the second sleeve can be 3 centimeters (“cm”), the gap between the second sleeve and the third sleeve can be 4 cm, the gap between the third sleeve and the fourth sleeve can be 3 cm and so on. The uniformity or the non uniformity can extend along the length of the sleeve members. 
     The length of the sleeves can also vary. In the embodiment wherein the sleeves extend inside the balloon, the first sleeve may be at least 1.5 times the length of the balloon and this could be as much as two to three times. The remainder of the sleeves are less than or equal to the length of the balloon. No direct or indirect correlation is intended between the length of the balloon and the length of the sleeves, this is given for exemplary comparative purposes only. 
     While the guidewire lumen as defined in known devices is essentially cylindrical in shape to accommodate a guidewire which is usually of lumen 0.014″ in diameter, the guidewire lumen according to the present invention may be of increasing diameter or conical in shape. This shape of the cone is on the body member where the sleeve member terminates. Only the lumen is intended to be a cone and the outside segment does not have a cone. Any shape other than a cylinder is recommended for this function, and one of ordinary skill in the art can select the optimum shape for the particular design and the intended function in accordance with the teachings herein. 
     The sleeve members with the gaps generally provide the following functionality. There is friction between the guidewire channel or the sleeve members and the guidewire essentially and this has to be overcome and the catheter pushed with a force that exceeds the friction plus the pushing force. The plurality of the sleeve members also acts like the wheels on a rail and provide the backbone which gives it the trackability. This trackability exceeds the trackability of the currently existing catheters. The pushability of the catheter is much better when compared to known catheters because the guidewire is intermittently exposed on the guidewire channel. The flexibility of the distal segment of the catheter is far better and the sleeves allow for small radius of turning during curves in the arteries. The inside of the sleeve members can be coated with lubricious material to ensure that the guidewire is extremely slippery when passed through it. 
     Because the sleeve member inside the balloon segment is conical in shape, it allows for a smoother transition zone at the ends of the balloon. Also, the proximal most sleeve member on the catheter body which is farthest from the balloon provides for a smooth transition segment with the body of the catheter. 
     In the embodiment where there is no plurality of sleeve members and just one sleeve running midway or otherwise into the balloon, this sleeve member is conically shaped such that the diameter of the distal outlet is smaller than the diameter of the proximate outlet. 
     The catheter can sometimes be reinforced with a hypotube or a wire inside the body member to enable it to be more pushable. Because of the sleeves and also the gaps between them, it may not be necessary to have such a hypotube or stiffening wire as the external guidewire provides all the pushability. 
     In FIG. 15, there is schematically shown a catheter  300  wherein the guidewire lumen is formed of sleeve member  302  through balloon  304  and also includes four sleeve members  306 ,  308 ,  309 , and  310  outside the balloon. Preferably the sleeve member  302  has a non-uniform cross section. In a preferred embodiment, sleeve member  302  is conical, truncated or tapered, i.e., it has an increasing cross sectional diameter from the distal end portion to the proximal end portion. As shown in FIGS. 16A and 16B, the cross-section in the direction A—A at the distal end is smaller than at the proximal end in the direction B—B. 
     Referring to FIG. 17, the catheter  312  has a guidewire channel  314  which is parallel to the body member inside the balloon. The sleeve members  316  and  318  outside the balloon are of varying length. They are also spaced equidistantly. 
     In FIG. 18, the catheter  320  has a guidewire channel that is parallel to the body member of the catheter and is formed of three sleeve members  322 ,  324 , and  326 . These sleeve members can be of the same or varying sizes and spaced apart at different or equal distances. Preferably, the sleeve members can be conical so that the cross section increases from  322  to  324  and again to  326 . Also, preferably, the cross section can increase continuously and progressively along the lengths of these sleeve members. 
     Turning now to FIG. 19, the catheter  328  has a guidewire channel is formed of four sleeve members  330 ,  332 ,  334 , and  336  which are formed by slots or cutouts  338 . Here again, the sleeve members can be of varying lengths and preferably can be conical in shape. 
     In FIG. 20, the catheter  340  includes four sleeve members  342 ,  344 ,  346 , and  348  through the balloon to form the guidewire channel. The sleeve members are spaced apart at equal or different distances along the and can be conical in shape. 
     In FIG. 21, the catheter  350  includes four sleeve members  352 ,  354 ,  356 , and  358 , with the first sleeve member  352  being positioned under the balloon and the remaining three guide members  354 ,  356  and  358  being spaced along the through body member. Guide members  354 ,  356  and  358 , as shown, are of increasing length to assist in guiding the guide wire to the distal end of the catheter. If desired, the guide members  354 ,  356  and  358  can be of essentially the same length, although the increasing length design that is shown is advantageous in that shorter and shorter lengths of guide members eliminate unnecessary material. The guide members may be conical in shape, if desired. 
     In FIG. 22, the catheter  360  includes three sleeve members  362 ,  364 , and  366  positioned beneath the balloon to form the guidewire channel. These sleeve members may be essentially equal in length and are preferably spaced apart equidistantly beneath the balloon. If desired, the sleeve members  362 ,  364 , and  366  may have increasing lengths similar to those of FIG. 21, they may be arranged in other than equidistant spacing and may be conical in shape. 
     In FIG. 23, the catheter  370  includes a guidewire channel that is integrated within the balloon and has only one sleeve member  372  extending from the distal tip of the balloon to the proximal tip of the balloon. 
     FIG. 24 shows an alternative embodiment of that shown in FIG. 23 with the catheter  380  having a guidewire channel that is integrated within the balloon and has a plurality of spaced sleeve members  382 ,  384 , and  386  extending from the distal tip of the balloon to the proximal tip of the balloon. The sleeve members do not extend substantially all the way on the body member but extend just proximal to the balloon. As above, these sleeve members may have different lengths or may be essentially equal in length and are preferably spaced apart equidistantly beneath the balloon. If desired, the sleeve members  382 ,  384 , and  386  may be arranged in other than equidistant spacing and may be conical in shape. 
     Another variation is shown in FIG. 25, where the catheter  390  has a guidewire channel which is formed of four sleeve members  392 ,  394 ,  336 ,  338  and  339  which are formed by slots or cutouts  335 . Here again, the sleeve members can be of equal or varying lengths and are preferably spaced apart equidistantly beneath the balloon. If desired, the sleeve members may be arranged in other than equidistant spacing and may be conical in shape. 
     With respect to the embodiments described and illustrated herein wherein there is only one lumen within the balloon, any gaps or openings between the sleeves will not inflate the balloon because of leakage through the gaps. In such case, an external sheath or bridge (not shown) may be placed between the sleeves and thus slightly overlap the two sleeves such that the external sheath is permanently fixed between the two sleeves. The balloon can then be mounted on the two sleeves. This arrangement will provide that the guidewire does not kink when passing through a bend, and also this sheath serves the purpose of not letting any dye or air leak when the balloon is being inflated. While the two sleeves themselves can be made of coils, sires or polymer, the bridge is made of a plastic material preferably a heat shrinkable polymer which has an ultra thin wall thickness. This bridge can also be made of a radiopaque material so that the entire section can be visualized under fluroscopy. 
     While the present invention has been described and illustrated herein with respect to the preferred embodiments thereof, it should be apparent that various modifications, adaptations and variations may be made utilizing the teachings of the present disclosure. For example, the balloon may have only a single guidewire lumen beneath it where the catheter body has a dual lumen construction under the balloon and a single lumen construction for the remainder. As above, the guidewire lumen can have a plurality of spaced sleeve members extending from the distal tip of the balloon to the proximal tip of the balloon. In this arrangement, the sleeve members do not extend substantially all the way on the body member but extend just proximal to the balloon. Also as above, these sleeve members may have different lengths or may be essentially equal in length and are preferably spaced apart equidistantly beneath the balloon. If desired, the sleeve members may be arranged in other than equidistant spacing and may be conical in shape. It is intended that all these modifications are included within the scope of the claims without departing from the teachings of the present invention.