Abstract:
An angioplasty catheter comprising a catheter shaft having a proximal portion and a distal end, an angioplasty balloon attached to the shaft at the distal end, a balloon inflation lumen extending through the shaft and communicating with the interior of the balloon, a guidewire lumen extending through the shaft and through the balloon for receiving a steerable guidewire, the guidewire lumen having an outside wall, wherein the guidewire lumen has a proximal opening located at a point normally outside of the patient during use of the catheter for insertion of a guidewire into the lumen, and a side port adapted to permit passage of a guidewire into the lumen through the outside wall of the guidewire lumen, the side port located distally of the proximal opening and at a point normally inside of the patient during use, and guidewire removing means in the outside wall of the guidewire lumen extending from the proximal opening to the side port for permitting a guidewire in the guidewire lumen to be moved laterally from the guidewire lumen through the outside wall of the guidewire lumen. Also disclosed are a removable “Y” connector and methods for using the catheter and for exchanging catheters and guidewires during vascular catheterization procedures.

Description:
RELATED APPLICATIONS 
   This application is a continuation of application Ser. No. 07/714,642 filed Jun. 13, 1991 now U.S. Pat. No. 6,824,554, the disclosure of which is hereby incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   This invention relates to vascular catheters (such as angioplasty catheters) specially adapted for rapid-exchange of both the guidewire and the catheter during use. It also relates to the method of using those catheters. 
   Percutaneous transluminal coronary angioplasty (PTCA) has emerged as the major viable present alternative to bypass surgery for revascularization of stenotic and occluded coronary arteries. Although transluminal angioplasty has application in peripheral artery disease, it is most widely used in the treatment of coronary artery disease. Unlike bypass surgery, percutaneous angioplasty does not require general anesthesia, cutting of the chest wall, extracorporeal perfusion, or transfusion of blood. Percutaneous coronary angioplasty is not only less invasive and less traumatic to the patient, it is also less expensive because the angioplasty patient will have a shorter hospital stay and shorter post-procedure recovery time. 
   Percutaneous transluminal angioplasty is performed by making a skin puncture with a specially-designed needle in one of the groins, and then introducing a guiding catheter (typically 8 or 9 French size) into the aorta and coronary artery orifice. A smaller caliber catheter which has a built-in inflatable and deflatable balloon of predetermined size and diameter is passed through the guiding catheter which is positioned in the opening of a target artery. This balloon catheter (with the balloon totally deflated by negative pressure) is advanced inside the target artery toward the point of obstruction that needs to be dilated. The guidewire plays an essential role in leading the balloon catheter to the target coronary artery in safety and non-traumatic fashion. With the balloon portion of the catheter properly positioned inside the obstructed segment of the artery, under X-ray fluoroscopic observation, the balloon is inflated by injecting contrast media mixed with saline at a pressure sufficient to overcome the resistance of the arteriosclerotic plaque of the obstructed segment. 
   By inflating the balloon in the stenosis multiple times over a period of between 10–30 seconds and one or two minutes (allowing blood flow between inflations), the desired dilation of the obstructed segment of the artery can be achieved. When the desired results have been obtained by balloon inflations, the guiding catheter, the balloon catheter (with the balloon completely deflated with negative pressure) and the guidewire are withdrawn from the artery and the patient and the procedure is successfully terminated. 
   The size and diameter of the balloon to be used in a transluminal angioplasty should be approximately matched to the size and native diameter of the obstructed segment of the artery to be dilated. If the balloon size and diameter is smaller than the native artery, the results of balloon angioplasty are suboptimal, requiring a second dilation with a larger-sized balloon, and if balloon size is too large for the native artery, complications may occur due to arterial wall damage. 
   During the angioplasty procedure, a guidewire is first advanced into the desired location, after which the angioplasty catheter is advanced over the guidewire. It is sometimes necessary to replace (or exchange) either the guidewire or the balloon catheter during the procedure. 
   If the balloon is undersized, for example, the catheter must be withdrawn and replaced with a larger balloon catheter in order to permit adequate dilatation of the lesion. With conventional over-the-wire catheters, in which the guidewire lumen extends the entire length of the catheter shaft, a guidewire extension (e.g., 145 cm long) must first be attached to the regular guidewire (e.g., 175 cm long) being used outside the patient before the catheter is withdrawn. This permits the distal end of guidewire to be held in position while the catheter is removed and a new catheter is exchanged. Usually, two to three operators are needed to effect such a catheter exchange. 
   The catheter disclosed in U.S. Pat. No. 4,762,129 avoids the necessity for extending the guidewire or exchange guidewire (e.g., 300 cm in length) by having a short guidewire lumen that extends substantially only through the distal end of the catheter. This type of catheter is referred to herein as a rapid-exchange catheter. Thus, the guidewire is outside the catheter shaft for much of the catheter length, and is inside the catheter at only the distal end. The catheter can be exchanged without extending the 175 cm regular guidewire, and the exchange can be effected by one or two operators. However, this catheter has a serious drawback of not being able to permit ready exchange of guidewires. In clinical practice, the need for guidewire exchange is more common. 
   Conventional over-the-wire angioplasty catheters, with a guidewire lumen extending their entire length, permit simple guidewire exchange. During angioplasty procedures, the guidewire tip may become damaged, may be needed of a different type of guidewire or may need to be reshaped to complement the patient&#39;s vasculature. The guidewire exchange procedure is readily accomplished with such a conventional over-the-wire catheter. However, with the rapid-exchange type catheter of U.S. Pat. No. 4,762,129, guidewire exchange requires complete removal and reinsertion of both the guidewire and the angioplasty catheter; thus, defeating the original goal of expedient advantage of the rapid-exchange catheter. 
   Another disadvantage of the rapid-exchange catheter is backbleeding. While the guidewire is being manipulated to select the target vessel or to cross the culprit lesion, the Tuehy-Borst adapter must be loosened. This, in turn, permits backbleeding to occur. 
   Accordingly, there is a need for an angioplasty catheter that permits rapid-exchange of both the catheter and the guidewire. There is also a need for a catheter that will permit the user to select the mode of usage between the rapid-exchange and the over-the-wire systems. 
   BRIEF SUMMARY OF THE INVENTION 
   In accordance with one aspect of the present invention, there is provided an angioplasty catheter comprising a catheter shaft having a proximal portion and a distal end, an angioplasty balloon attached to the shaft at the distal end, a balloon inflation lumen extending through the shaft and communicating with the interior of the balloon, a guidewire lumen extending through the shaft and through the balloon for receiving a steerable guidewire, the guidewire lumen having an outside wall, wherein the guidewire lumen has a proximal opening located at a point normally outside of the patient during use of the catheter for insertion of a guidewire into the lumen, and a side port adapted to permit passage of a guidewire into the lumen through the outside wall of the guidewire lumen, the side port located distally of the proximal opening and at a point normally inside of the patient during use, and guidewire removing means in the outside wall of the guidewire lumen extending from the proximal opening to the side port for permitting a guidewire in the guidewire lumen to be moved laterally from the guidewire lumen though the outside wall of the guidewire lumen. In one embodiment, the side port is located adjacent to and proximally of the balloon, preferably within about 35 cm of the balloon. One embodiment of the guidewire removing means is a slit through the outside wall of the catheter shaft. This slit may be continuous from the proximal opening to the side port or may be discontinuous, forming a perforated line from the proximal opening to the side port. In another embodiment, the guidewire removing means is a weakened area of the wall of the guidewire lumen adapted to be severed for removal of the guidewire therethrough. One variation of the invention provides a second side port communicating with the interior of the guidewire lumen. Another provides a perfusion opening communicating with the interior of the guidewire lumen, the perfusion opening located between the side port and the balloon. Still another embodiment includes a “Y” connector at the proximal opening having an axial portion through which the balloon inflation lumen extends and a side portion through which the guidewire may be inserted into the guidewire lumen, wherein at least a portion of the connector can be removed from the catheter shaft to permit a guidewire extending through the connector and into the guidewire lumen to be removed through the guidewire removing means. The connector is advantageously adapted to be separated longitudinally and at least a portion thereof removed from the catheter shaft. In one variation, the connector comprises two longitudinally separable portions having first and second longitudinal sides on different sides of the catheter shaft, the portions being hingedly joined at the first longitudinal side and separably joined at the second longitudinal side. 
   Another embodiment of the present invention comprises an intravascular catheter comprising a catheter shaft having a proximal end and a distal end, wherein a portion of the catheter including the distal end is normally inside a patient during use and the proximal end is normally outside the patient or outside the guiding catheter, a guidewire lumen extending through the shaft for receiving a steerable guidewire, wherein the guidewire lumen has an outside wall, and a proximal opening at the proximal end of the shaft for insertion of a guidewire into the lumen, and means formed in the outside wall of the guidewire lumen extending distally from the proximal opening to a point normally inside the patient during use of the catheter for permitting a guidewire in the guidewire lumen to be moved laterally from the guidewire lumen through the outside wall of the guidewire lumen. The guidewire removing means may be a slit, fully formed or inchoate. The catheter preferably includes a side port through the outside wall of the guidewire lumen for passage of a guidewire into through the side of the catheter shaft, the side port located distally of the proximal opening and normally inside of a patient during use of the catheter. In one embodiment of the catheter, the guidewire removing means is a slit and the slit is continuous from the proximal opening to the side port. In another, the guidewire removing means is a slit and the slit is discontinuous, forming a perforated line from the proximal opening to the side port. In still another embodiment, the guidewire removing means is a weakened area of the wall of the guidewire lumen adapted to be severed for removal of the guidewire therethrough. According to one modification, the catheter may further comprise a second side port communicating with the interior of the guidewire lumen. 
   The present invention also includes a catheter for use in an animal body with a guidewire, comprising a catheter shaft having a proximal end and a distal end with at least two lumens extending therethrough, and a “Y” connector surrounding at least a portion of the proximal end of the catheter shaft and having at least two arms, one arm providing an access channel into one of the lumens and another arm providing an access channel into another of the lumens, wherein the “Y” connector has at least two segments joined together in a separable manner along a longitudinal line so that upon separation of the segments, the “Y” connector no longer surrounds the portion of the proximal end of the catheter shaft. In one embodiment, upon separation of the segments, one of the segments is completely removable from the catheter shaft. In another embodiment, upon separation of the segments, the connector is completely removable from the catheter shaft in such a manner that an elongate object extending through one arm of the connector into a lumen of the catheter shaft can remain in the lumen during such removal of the connector. 
   The invention further includes a method of removing a catheter during a procedure involving vascular catheterization, comprising the steps of providing a catheter of the type described above having a guidewire passing through the guidewire lumen from the proximal opening to the distal opening thereof and positioning the catheter in a patient with the prximal end of the guidewire extending proximal opening, holding the proximal end of the guidewire to maintain the positioning of the guidewire in the patient while removing the catheter from the patient by moving the guidewire laterally out of the guidewire lumen through the guidewire removing means until the entire catheter is outside the patient and outside the guiding catheter and a portion of the guidewire is exposed at the distal end of the catheter, and then holding the exposed portion of the guidewire and removing the catheter off of the proximal end of the guidewire. The method may also include inserting another catheter, with the guidewire in the guidewire lumen at the distal portion of the catheter and either remaining in the guidewire lumen for the entire length of the catheter that is inside the patient during use, or extending out through the side of the catheter and running parallel to the catheter proximal of the distal portion of the catheter. 

   
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a foreshortened plan view of a catheter according to the present invention. 
       FIG. 1A  is a transverse cross section of the catheter of  FIG. 1 , taken along the line A—A. 
       FIG. 1B  is a transverse cross section of the catheter of  FIG. 1 , taken along the line B—B. 
       FIG. 1C  is a transverse cross section of the catheter of  FIG. 1  corresponding to  FIG. 1B , but illustrating the opening of the guidewire removing means. 
       FIG. 2  is a fragmentary view of a portion of the catheter shaft of the  FIG. 1  catheter surrounding the proximal opening, illustrating one variation of the guidewire removing means. 
       FIG. 3  is a longitudinal cross section of the catheter of  FIG. 1  taken along the line  3 — 3 , illustrating the guidewire in place and the function of the guidewire removing means. 
       FIG. 4  is a cross sectional fragmentary perspective view of the catheter of  FIG. 1 , taken along the line B—B, illustrating another variation of the guidewire removing means. 
       FIG. 5  is a longitudinal cross section corresponding to  FIG. 3 , illustrating movement of the guidewire laterally out of the guidewire removing means. 
       FIG. 6  is a foreshortened longitudinal cross section of the proximal end of one embodiment of the catheter of the present invention. 
       FIG. 7  is a perspective view of a removable “Y” connector at the proximal end of the catheter shaft. 
       FIG. 8  is a detailed perspective view of a locking mechanism on the “Y” connector of  FIG. 7 . 
       FIG. 9  is a transverse cross section taken along the line  9 — 9  in  FIG. 7 . 
       FIG. 10  is a detailed perspective view of another locking mechanism on the “Y” connector of  FIG. 7 . 
       FIG. 11  is an exploded transverse cross section corresponding to  FIG. 9 , illustrating removal of the “Y” connector from the catheter shaft. 
       FIG. 12  is a perspective view of the distal end of the catheter shaft after removal of the “Y” connector, illustrating a sealing member. 
       FIG. 13  is a longitudinal cross section of the removable “Y” connector, taken along the line  13 — 13  in  FIG. 7 . 
       FIG. 14  is a longitudinal cross section of the entire catheter, taken along the line  13 — 13  in  FIG. 7 . 
       FIG. 15  corresponds to  FIG. 14 , except that the guidewire is illustrated in place in the guidewire lumen. 
   

   The foregoing summary, as well as the following detailed description of the preferred embodiments of the present invention, will better understood when read in conjunction with the appended drawings. For the purpose of illustrating the preferred embodiments of the present invention, there is shown in the drawings, embodiments which are presently preferred. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings. 
   DETAILED DESCRIPTION OF THE INVENTION 
   A basic embodiment of the catheter of the present invention is illustrated in  FIG. 1 . A catheter  10  is provided with a catheter shaft  12  extending from a proximal end  14  to a distal end  16 . As shown more clearly in  FIG. 1B , the interior of the catheter shaft  12  has a guidewire lumen  20  and a balloon inflation lumen  22  extending through the catheter shaft  12 . 
   The catheter  10  has an angioplasty balloon  24  at the distal end  16  thereof. At the proximal end  14  of the catheter shaft  12 , a balloon inflation connector  26  is provided in fluid communication with the balloon lumen  22 . Fluid introduced into the proximal end of the balloon inflation connector  26  can travel through the balloon lumen  22  and into the interior of the balloon  24  to inflate and deflate the balloon  24  during an angioplasty procedure. The balloon inflation lumen  22  terminates inside the balloon  24 . The opposite end of the balloon inflation lumen  22  terminates inside the balloon inflation connector  26 . 
   The guidewire lumen  20  is adapted to receive a steerable guidewire and has an outside wall  30  (shown in  FIG. 1B ). 
   A proximal opening  32  is provided through the outside wall  30  of the guidewire lumen  20 . This proximal opening  32  is situated in the proximal portion of the catheter shaft  12  at a location sufficiently close to the proximal end  14  that it is normally outside of the patient during the angioplasty (or other vascular procedure). Typically, the proximal opening  32  will be within 60 cm, preferably within about 40 cm, more preferable within about 30 cm of the proximal end  14  of the catheter  10 . 
   The balloon  24  is made in accordance with conventional techniques for fabricating angioplasty balloons. Preferably, it is either blown from the distal end  16  of the catheter shaft  12 , or is blown or formed of a separate piece of material which is bonded to the distal end of  16  of the catheter shaft  12 . The balloon  24  may advantageously be formed of relative inelastic polymer material, such as polyethylene, polypropylene, polyvinylchloride, polyethylene terephthalate, and the like. 
   The catheter shaft  12  is also provided with a side port  34  which extends through the outside wall  30  of the guidewire lumen  20 . The side port  34  is located distally of the proximal opening  32 , and is located at a point normally inside of the patient when the catheter is properly placed for performance of an angioplasty procedure. Preferably, the side port  34  is located proximally of the balloon  24  and within 80 cm, preferably 60 cm, and more preferably about 40 cm of the balloon  24 . 
   The catheter  10  of the present invention is provided with a means for removing a guidewire that is inside of the guidewire lumen out of the guidewire lumen  20  through the outside wall  30  of the guidewire lumen  20 . If the catheter shaft  12  or the guidewire is considered to extend in a longitudinal or axial direction, this movement of the guidewire out of the guidewire lumen  20  can be considered as a sideways, radial, or transverse motion of the guidewire. The guidewire removing means  40  is adapted to form a slit through the outside wall  30  of the guidewire lumen  20  through which the guidewire may be removed from inside the guidewire lumen  20 . The guidewire removing means  40  may be an actual slit cut entirely through the side wall  30  of the guidewire lumen  20  as illustrated in  FIG. 1C . Alternatively, it may an inchoate slit such as the weakened area illustrated in  FIG. 1B . The guidewire removing means  40  may be cut entirely through the outside wall  30  of the guidewire lumen  20  only in certain sections, leaving other sections at least partially intact, to form a sort of perforated line. It may be formed of a different material than the remainder of the catheter shaft  12  and even of a different material than the adjacent portions of the outside wall  30  of the guidewire lumen  20 . 
   One advantage of having only an inchoate slit is that it prevents backbleeding out of the guidewire removing means  40  during performance of the procedure. It is possible, however, to use an inchoate slit for only the portion of the guidewire removing means  40  that is outside of the guiding catheter in use. The remainder of the guidewire removing means  40  that is outside the patient and outside the guiding catheter can be a fully formed slit or a perforated slit without creating backbleeding problems. 
   As illustrated in  FIG. 2 , the guidewire removing means  40  may comprise a removable tear strip  42  defined by a pair of weakened lines  44 ,  46  extending distally from the proximal opening  32 . 
   The guidewire removing means  40  extends from the proximal opening  32  distally along the length of the catheter shaft  12  to a point that is ordinarily inside the patient when the catheter  10  is properly placed for performance of an angioplasty procedure. Thus, the guidewire removing means  40  begins at a point ordinarily outside the patient and outside the guiding catheter upon proper placement of the catheter  10  and extends distally to a point ordinarily inside the patient upon such placement. From another perspective, it can be said that the guidewire removing means  40  extends distally for at least 40 cm, preferably at least 60 or 70 cm, and more preferably at least 80, 90 or 100 cm. 
   The guidewire removing means  40  may advantageously extend distally to the side port  34 , and in one embodiment of the invention, may extend an additional distance distally beyond the side port  34 . The guidewire removing means  40  preferably terminates proximally of the balloon  24 , and may be immediately adjacent the balloon  24  or may be 5 cm, 10 cm, or more proximally of the balloon  24 . 
   If the guidewire removing means  40  is not a slit prior to its use, it becomes a slit or opening after use, as illustrated in  FIG. 1C . 
   The use of the catheter  10  of the present invention is illustrated in  FIG. 3 . In this longitudinal cross sectional view, the catheter  10  is illustrated with a guidewire  50  in place in the guidewire lumen  20 . The proximal portion of the guidewire  50  is outside of the catheter  10 . The guidewire  50  passes-through the proximal opening  32  into the guidewire lumen  20 , and is inside the guidewire lumen  20  for the entire length of the catheter shaft  12  that extends distally from the proximal opening  32 . The distal end of the guidewire  50  extends out of the distal end  16  of the catheter shaft  12 . 
   When the guide wire is to be removed radially or laterally out of the guidewire lumen  20 , the guidewire removing means  40  provides a slit or opening in the outside wall  30  of the guidewire lumen  20  through which the guidewire  50  may be removed from the guidewire lumen  20 . This slit or opening, if not fully formed, may be completed by cutting the outside wall  30  of the guidewire lumen  20 , by tearing or rupturing a weakened area in the outside wall  30 , or by tearing loose a removable strip (as illustrated in  FIG. 2 ). In a preferred embodiment the guidewire removing means  40  is a weakened area that is fully opened only when the guidewire  50  is removed through the guidewire removing means  40 . In one embodiment, the guidewire  50  is simply pulled through the outside wall  30  of the guidewire lumen  20 . Alternatively, as illustrated in  FIG. 4 , the catheter shaft  12  may be provided with a filament  52  in association with the guidewire removing means  40 . The filament  52  may be a continuous fiber or strand extending along the length of the guidewire removing means and inside at least a portion of the outside wall  30  of the guidewire lumen  20 . When the filament  52  is pulled outwardly, it tears a slit into the outside wall  30  of the guidewire lumen  20 . 
   In  FIG. 3 , the initial removal of the guidewire  50  through the guidewire removing mans  40  is illustrated in phantom. In that figure, a phantom guidewire  50  is illustrated extending through the outside wall  30  of the guidewire lumen  20  at a point distally of the proximal opening  32 . 
   As illustrated in  FIG. 5 , the phantom guidewire  50  is pulled through the outside wall  30  of the guidewire lumen  20  until the guidewire  50  has been removed through the outside wall  30  up to the side port  32 . It will be understood, of course, that in accordance with the present invention, the guidewire  50  may be removed through the outside wall  30  to a point proximal of or distal of the side port  34 ; however, in a preferred embodiment, the lateral removal out of the guidewire lumen  20  continues up to the side port  34 . 
   It should be noted that the removal of the proximal portion of the guidewire  50  through the outside wall  30  can be accomplished without longitudinal or axial movement of the distal portion of the guidewire  50 . Thus, in  FIG. 3 , the distal tip of the guidewire  50  is in the same position as in  FIG. 5 ; however, in  FIG. 5 , the guidewire has been removed laterally through the guidewire removing means along a portion of the length of the catheter shaft  12 . 
   In the simplest embodiment of the present invention the guidewire lumen  20  may be provided simply with a proximal opening  32 , a side port  34 , and guidewire removing means  40  extending distally of the proximal opening  32  at least to the side port  34 , and perhaps beyond. 
   However, more sophisticated versions of the present invention are also contemplated. In one such embodiment, a distal side opening  54  may be provided through the outside wall  30  of the guidewire lumen  20  to provide access into the guidewire lumen  20  at a point distal of the sideport  34 . The distal side opening  54  may be open in normal use; however, the distal side opening  54  is preferably covered with a removable patch  56 , as best seen in  FIGS. 3 and 5 . The removable patch  56  is preferably made of foil, Mylar, aluminized or metalized Mylar, or other suitable material, and may be held in place with an adhesive. The removable patch  56  may be removed from the catheter shaft  12  to open up the distal side opening  54  to permit extension of the guidewire  50  through the distal side opening  54  or to permit use of the distal side opening  54  as a perfusion opening. In one embodiment of the invention, the guidewire removing means  40  extends distally to the distal side of the distal side opening  54 . 
   The portion of the guidewire lumen  20  located proximally of the proximal opening  32  is preferably closed, and may be filled with a filler  60  such as a polymer material formed in place or a stylet inserted in a waterproof manner into the guidewire lumen  20 , as illustrated in  FIGS. 3 and 5 . 
   In an alternative embodiment the invention, the catheter of  FIG. 1  is modified at its proximal end as illustrated in  FIG. 6 . Specifically, this particular catheter has a conventional “Y” connector  62  at the proximal end  14  of the catheter shaft  12  has the balloon inflation connector  26  and a guidewire connector  64  at the two “branches” of the “Y”. The guidewire lumen  20  extends from the proximal end  14  of the catheter shaft  10  through the guidewire connector  64  and the “Y” connector  62  and extends distally the length of the catheter shaft  12 . 
   The proximal opening  32  is located distally of the “Y” connector  62 . The catheter  10  is provided with a sliding cover  66  that is axially movable to cover or uncover the proximal opening  32 . The sliding cover  66  is preferably an annular sleeve circling the catheter shaft  12  and axially movable with respect thereto. The sliding cover  66  preferably has a soft sealing material  70  (such as a pliable closed cell polymer foam, a silicone elastomer, or other suitable material) on its inside surface to provide a seal against the catheter shaft  12 . Ordinarily, the sliding cover  66  is over the proximal opening  32 , closing and sealing the proximal opening  32 . 
   In an alternative embodiment, the sliding cover  66  may be replaced by a removable covering (not illustrated) similar to the removable patch  56  to close the proximal opening  32  until it is used. 
   In ordinary use, the guidewire  50  extends distally through the guidewire connector  64 , the remainder of the “Y” connector  62 , inside the guidewire lumen  20 , past the proximal opening  32 , and out of the distal end  16  of the catheter  10 . When required (as will be explained in more detail hereafter), the sliding cover  66  or other seal covering the proximal opening  32  is removed, the catheter  10  is maintained in place in the patient while the guidewire  50  is removed proximally out of the guidewire connector  64 , and the guidewire  50  is then inserted through the proximal opening  32  until it is in the desired position. Then the guidewire  50  is removed out through the outside wall  30  of the guidewire lumen  20  as explained in more detail elsewhere. Removal of the guidewire  50  through the outside wall of the catheter shaft  12  permits conversion of the catheter from an over-the-wire catheter to a rapid-exchange catheter that can be removed from the patient without extension of the guidewire  50 . 
   In the embodiment illustrated in  FIG. 6 , because a conventional guidewire connector  64  is ordinarily used, backbleeding during use is eliminated by tightening the Tuehy-Borst adapter (not shown) except when manipulating the guidewire  50 . This is in contrast to the embodiment illustrated in  FIG. 1 , where some backbleeding might be expected. 
   In yet another embodiment of the invention, the guidewire removal and reinsertion explained in connection with  FIG. 6  is eliminated by providing a removable “Y” connector  80 , illustrated in  FIGS. 7–13 . 
   The particular embodiment of removable “Y” connector illustrated in  FIG. 7  provides an axially separable “Y” connector  80 . The “Y” connector  80  is preferably molded of a relatively hard thermoplastic material, and is adapted to fit concentrically around the catheter shaft. The removable “Y” connector  80  is formed of 2 (or more) pieces which are joined together along lines extending in the axial or longitudinal direction of the catheter shaft  12 . In the illustrated embodiment, the removable “Y” connector has an axial portion  82  through which the balloon lumen  22  (and preferably the catheter shaft  12 ) extends. The removable “Y” connector  80  further has a guidewire connector  64  extending proximally and at an angle outwardly from the axial portion  82  of the removable “Y” connector  80 . 
   The guidewire connector  64  of the removable “Y” connector  80  is cylindrical in shape and has a guidewire bore  84  extending therethrough. The guidewire bore  84  connects through the proximal opening  32  into the guidewire lumen  20 , as best illustrated in  FIG. 13 . 
   The removable “Y” connector  80  is preferably formed of a first half  86  and second half  90 . The first half  86  and the second half  90  each has a semi cylindrical recess  92 ,  94  extending axially along the length of each half  86 ,  90  of the removable “Y” connector  80 . The semi cylindrical recesses  92 ,  94  are best illustrated in  FIG. 11 . When the first and second halves  86 ,  90  are joined together, the semi cylindrical recesses  92 ,  94  together form a cylindrical recess through which the catheter shaft  12  extends. 
   When the first and second halves  86 ,  90  are joined together on the catheter shaft  12 , they are joined at a first edge  96  and a second edge  100  on opposite sides of the catheter shaft  12 . The first and second edges  96 ,  100  of each half  86 ,  90  extend axially parallel to the axis of the catheter shaft  12 . 
   In a preferred embodiment of the invention, the first edges  96  of the first and second halves  86 ,  90  are joined by a hinge  102 . Preferably, the hinge  102  is a “live” hinge; that is, a hinge formed of a thin portion of the polymer material of which the removable “Y” connector  80  is formed. In a preferred embodiment, the hinge  102  extends axially the entire length of the first edge  96 . 
   The second edges  100  of the first and second halves  86 ,  90  are separably joined together by any appropriate connecting mechanism. The illustrated mechanism is but one possibility. In the illustrated mechanism, the second edge  100  of the first and second halves  86 ,  90 , comprises on each half a radially extending tab  104  running the length of the second edge  100 . At the outside radial edge of the tabs  104  is a flange  106  formed so that, when the first and second halves  86 ,  90  are mated together at their second edges  100 , the flanges  106  extend in opposite directions on the first and second halves  86 ,  90 , forming a “T” shape in radial cross section as shown in  FIG. 9 . 
   An edge connector  110  is provided to hold the second edges  100  of the first and second halves  86 ,  90  together. The edge connector  110  preferably extends the entire length of the second edges  100  and is formed with a “T” channel inside to lock together the tabs  104  and flanges  106  of the second edges  100  of the first and second halves  86 ,  90 . Thus, the “T” of the mated second edges of the first second edges  100  of the first and second halves  86 ,  90  is adapted to slide inside the “T” channel of the edge connector  110 . Once the connector  110  is placed on the “T” of the second edges, it may be locked in place using any appropriate mechanism. In one embodiment, a first end  112  of the connector is permanently closed to prevent movement of the edge connector  110  in one direction. The second end  114  of the edge connector  110  may have a breakaway end  116 , as illustrated in  FIGS. 7 and 8 . The breakaway end  116  is glued or otherwise connected to the remainder of the connector  110  in such a manner that it may be readily severed from the edge connector  110 . This may be done by a rocking motion applied to the breakaway end  116  as illustrated in by the arrows  120  in  FIG. 7 . Once the breakaway end  116  is removed as illustrated in  FIG. 8 , the connector  110  may be moved axially in the direction indicated by arrow  122  until the edge connector  110  is removed from the remainder of the removable “Y” connector  80 . 
   Another method for locking the edge connector  110  onto the removable “Y” connector  80  is by use of a locking pin  124  as illustrated in  FIG. 10 . The locking pin may extend through the edge connector  110  and the second edges  100  of the first and second halves  86 ,  90 , to lock the edge connector  100  in place. When the pin  124  is removed, the edge connector  110  may also be removed. 
   Although the pin  124  illustrated in  FIG. 10  is circular, any other suitable pin or locking device may similarly be used. 
   After the removal of the edge connector  110 , the first and second halves  86 ,  90  may be removed from the catheter shaft  12  as illustrated in  FIG. 11  by pivoting the second edges  100  away from each other. The removable “Y” connector  80  may then be slid proximally off the proximal end of the guidewire  50 . 
   In a preferred embodiment of the invention, a seal  126  is provided around the catheter shaft  12  as illustrated in  FIG. 12 . The seal  126  prevents leakage between the removable “Y” connector  80  and the catheter shaft  12 , and is preferably formed of annular polymer material such as elastomeric material or closed cell foam. The seal  126  is preferably provided with an index feature  130  for preventing rotational or longitudinal movement of the in-place “Y” connector  80  with respect to the catheter shaft  12 . In the illustrated embodiment, the index feature  130  is an outwardly extending tab; however, the index feature  130  could alternatively be a groove, a recess, a flange, or the like. The outwardly-extending index feature  130  illustrated in  FIGS. 12 and 11  can cooperate with a complimentary index receptacle  132  on the axial portion  82  of the removable “Y” connector  80 . 
   The use of the removable “Y.” connector is further illustrated in  FIGS. 14 and 15 . The catheter  10  without the “Y” connector  80  in place is illustrated in  FIG. 14 . A guidewire  50  is inserted, into the proximal opening  32  through the guidewire connector  64 , as seen in  FIG. 15 . The guidewire  50  extends the length of the catheter shaft  12  and out of the distal end  16  of the catheter  10 . 
   When the removable “Y” connector  80  is removed from the catheter shaft  12 , the catheter  10  is properly illustrated in  FIG. 3 , and the guidewire  50  can be removed laterally through the outside wall  30  of the guidewire lumen  20  as illustrated in  FIGS. 3 and 5 , and as previously explained. 
   Although the removable “Y” connector  80  has been discussed in the context of a particular preferred embodiment, it will be understood that equivalent removable “Y” connectors can be provided in which only a portion (such as a strip) of the “Y” connector is removed from the catheter shaft  12 ; or where there are more than two separable pieces of the “Y” connector; or where alternative latches or locking mechanisms are utilized to hold the removable “Y” connector together until removal is desired. Further, other mechanical features having equivalent function can be substituted for others of the various described elements. 
   Methods of using the Convertible Mode Catheter 
   The catheter of the present invention may be used as a rapid-exchange catheter with the guidewire  50  extending through the side port  34  and out of the distal end  16  of the guidewire lumen  20 . Alternatively, it may be used as a conventional over-the-wire catheter with the guidewire  50  extending substantially the entire length of the catheter shaft  12  from the proximal end (either through a conventional “Y” connector  62  or a removable “Y” connector  80  or through the proximal opening  32 ) distally through the entire length of the catheter shaft and out of the distal end thereof. 
   A revolutionary aspect of the catheter of the present invention is that it may readily and rapidly be converted from one mode of use to the other. Thus, it can be used first as a rapid-exchange catheter, with the guidewire extending in the guidewire lumen  20  only from the side-port  34  to the distal end of the catheter. It can be converted from this rapid-exchange mode of use to conventional over-the-wire use simply by removing the guidewire and, while maintaining the catheter  10  in place in the patient, inserting a new guidewire  50  into the proximal end of the guidewire lumen  20  (through a “Y” connector or through the proximal opening  32 ) and extending the guidewire  50  out of the distal end of the catheter  10 . 
   When the catheter of  FIG. 4  is being used as a conventional over-the-wire catheter, it can be converted into a rapid-exchange catheter by removing the removable “Y” connector  80  (if used), and, with the guidewire extending proximally out of the proximal opening  32 , maintaining the guidewire  50  in position in the patient while moving the guidewire laterally out of the outside wall  30  of the guidewire lumen  20  through the guidewire removing means  40  and simultaneously withdrawing the catheter  10  proximally until the distal end  16  of the catheter  10  is outside of the patient. During this portion of the procedure, the guidewire  50  is held by grasping it at the proximal end. Then the operator may hold the guidewire  50  by grasping the portion of the guidewire  50  exposed at the distal end  16  of the catheter  10 , remove the catheter  10  off of the proximal end of the guidewire  50 , and insert a new catheter  10  over the guidewire  50  while maintaining the position of the guidewire  50  in the patient. The insertion of the new catheter  10  may be accomplished in rapid-exchange mode by retrograde insertion of the proximal end of the guidewire  50  through the distal end of the catheter and out of the side port  34 . The proximal end of the guidewire is then held while the catheter  10  is advanced back into position in the patient. The catheter can then be used as a rapid-exchange catheter. Alternatively, if desired, the guidewire  50  may be removed with the catheter maintained in position, and in a matter of seconds the guidewire may be reinserted through the proximal opening  32  or through the proximal end  14  of the catheter shaft  12  to convert the mode of use to conventional over-the-wire use. 
   Thus, it will be appreciated that the catheter of the present invention can easily be used in either a rapid-exchange mode or an over-the-wire mode; that conversion between modes of use may be readily accomplished; that guidewire exchange may be accomplished in either mode of use, and that catheter exchange when in either mode of use can be accomplished without use of an extension guidewire; and that all of the forgoing conversions and modes of use can be accomplished while maintaining the positioning of either the guidewire or the catheter in the patient. 
   Thus, one method of the present invention comprises inserting the catheter of  FIG. 1  into the patient with the guidewire  50  going through the proximal opening  32  and extending from that point distally through the entire remaining length of the catheter shaft  12  and out of the distal end  16 . The guidewire  50  can then be exchanged by removing it and reinserting it through the proximal opening  32 . The catheter can be exchanged by holding the guidewire as explained above while peeling away the catheter laterally while withdrawing it so that the guidewire is pulled through the guidewire removing means  40  until the distal end of the catheter is outside the patient. The guidewire is then held distally of the catheter and a new catheter is inserted, this time in rapid-exchange mode. Once that catheter is in place, the guidewire can be rapidly exchanged (if desired) to convert the catheter back into the over-the-wire mode of use as explained above. 
   In another method of use, the catheter of  FIG. 6  can be used. This catheter can be used with the guidewire in the side port or the proximal opening, as explained above, with the same catheter and guidewire exchanges possible. Moreover, it can be used with the guidewire extending through the entire length of the guidewire lumen  20  through the guidewire connector  64 . Exchange of the guidewire from the guidewire connector  64  to the proximal opening  32  and vice versa is also contemplated. 
   The identical modes of use explained in connection with the  FIG. 1  catheter can be used with the removable “Y” connector catheter of  FIGS. 7–15 , except the guidewire passes simultaneously through the proximal opening  32  and the guidewire adapter  64  of the removable “Y” connector  80 . Further, in these modes of use, the conversion from over-the-wire use to rapid-exchange use will require removal of the “Y” connector  80  prior to and in addition to use of the guidewire removing means  40 . 
   Although the present invention has been described in the context of certain preferred embodiments, it is intended that the scope of the present patent be measured with reference with the appended claims and reasonable equivalence thereof. 
   While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.