Abstract:
A balloon angioplasty apparatus includes a guide wire, a balloon catheter, and a guide catheter. The balloon catheter has slots formed in it to define a plurality of elongate members between the slots. A joint is formed at the proximal, distal, and mid-point of each elongate member. Displacing the proximal and distal joints toward one another causes the respective middle joints to displace radially outwardly, and radial inward travel of the middle joints is caused by increasing the distance between the proximal and distal joints. A mesh that captures emboli overlies the jointed members and opens and closes with them. The guide catheter is used to close the joined members and the emboli-capturing mesh at the conclusion of the angioplasty procedure. In a second embodiment, the jointed members are formed in a delivery catheter. In a third embodiment, the jointed members are formed in a guide wire.

Description:
CROSS REFERENCE TO RELATED DISCLOSURES 
     This disclosure is a divisional application claiming the benefit of the filing date of U.S. patent application entitled “Emboli Capturing Device”, by the same inventor, filed Oct. 25, 1999, bearing Ser. No. 09/426,438, now U.S. Pat. No. 6,264,672. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates, generally, to endovascular surgical tools. More particularly, it relates to a tool used in balloon angioplasty and stenting of blood vessel narrowings (stenoses). 
     2. Description of the Prior Art 
     Percutaneous angioplasty is an efficacious treatment for improving the blood carrying capacity of an artery that has become occluded by plaque, calcification, and other deposits. There are several ways of performing the procedure and the type and number of catheters and other tools used may vary between differing procedures. Typically, a needle puncture is made into an artery and an elongate guide wire is fed through the puncture site until it has traversed the stenotic lesion (the area where the plaque has built up). A guide catheter having a relatively large diameter is then introduced into the artery, using the guide wire to guide it. A balloon-carrying catheter is then fed through the guide catheter, also using the guide wire as a guide. The guide catheter is then advanced to a preselected point so that its distal end is downstream of the stenotic lesion, and the balloon catheter is positioned so that the balloon is in registration with said lesion, also known as a stenosis. The guide catheter is withdrawn a relatively short distance to expose the balloon catheter. The balloon is then inflated to permanently dilate and tear the two inner layers of the artery, thereby enlarging its diameter, breaking up the stenosis, thereby increasing the blood-carrying capacity of the artery. An expandable stent may be carried on the outer surface of the balloon and left in place after the balloon is deflated and withdrawn. Alternatively, a self-expanding stent may be deployed over the treated lesion using a different delivery catheter. The stent holds the arterial walls in their expanded condition. After the balloon is deflated, the balloon catheter is withdrawn into the guide catheter, and both of said catheters and the guide wire are withdrawn to conclude the procedure. 
     The primary drawback to balloon angioplasty or stenting is the creation of debris and thrombus that can clog blood vessels downstream of the treatment site. The stretching of the two inner arterial walls breaks up the stenotic lesion and creates debris known as emboli. Accordingly, when the balloon is deflated, the emboli flow downstream with the blood. If the stenotic lesion is in the iliac or femoral arteries, the emboli may flow to the feet; this may or may not be problematic. However, if the stenotic lesion is in the carotid artery, the emboli can flow into various brain vessels and cause permanent brain damage. Similarly, kidney damage can ensue from dilating a lesion in the main renal artery. For this reason, balloon angioplasty carries a higher risk of embolic complications for stenotic lesions in the carotid, renal, and coronary arteries unless means are provided for preventing the flow of emboli to the blood vessels of the brain, kidney, or heart, respectively. 
     U.S. Pat. No. 5,833,644 discloses a complex catheter system that deploys at least two additional balloons that flank the main balloon that stretches the blood vessel. When inflated, the auxiliary balloons isolate the treatment area so that emboli cannot flow therefrom. However, no blood can flow to the brain when the auxiliary balloons are inflated, so the physician must perform the treatment in an expedited manner to avoid brain damage arising from oxygen deprivation. This can result in less than optimal treatment. Catheters of this type also include dedicated lumens for aspiration and irrigation and may require a complex electromechanical system to operate and control the saline flow rate, pressure, and the like. 
     PCT patent application No. PCT/US98/01894 filed by Yadav, published Aug. 6, 1998, discloses an emboli-catching device that is mounted to the distal end of a guidewire. It is positioned downstream of the stenotic lesion and opened up, much like an umbrella, to catch the emboli created by inflation of the angioplasty balloon. It is designed for use in the carotid artery and is formed of a material that is permeable to red blood cells so the brain is not deprived of oxygen during its deployment. However, since it must be positioned downstream of the stenotic lesion, it cannot be used in the lower half of the body because such use would require that it be fed to its operative location from a point in the upper half of the body. Moreover, the mechanism required to deploy and retract the emboli-catching means requires a dedicated sheath which makes the procedure relatively complex. 
     Several prior art emboli-catching devices also rely upon mesh-carrying frames that are formed of a flexible and resilient material such as a nickel-titanium alloy. The problem with such devices is that they pop open when they emerge from a containment catheter. Some of them spring open under their inherent bias until they hit the interior walls of an artery, and others spring open to a predetermined diameter that may be less than the diameter of an artery. In either case, the physician cannot instantaneously control the amount of opening or closing of the mesh. In other words, the nickel-titanium devices are either fully open or fully closed and the physician cannot open or close such devices to an infinite plurality of functional positions of adjustment because the opening or closing of the emboli-catching device is not under the positive control of the physician. 
     What is needed, then, is an emboli containment and removal device that does not block blood flow when in use, which can be used with any diagnosis or treatment catheter, which is small, which is mechanically simple in construction, and which is under the positive control of the physician. Moreover, such a device is needed that can be used in the carotid artery and in other blood vessels, including those in the region of the kidneys, heart, and peripheral blood vessels. 
     However, it was not obvious to those of ordinary skill in this art how the needed improvements could be provided, in view of the art considered as a whole at the time the present invention was made. 
     SUMMARY OF THE INVENTION 
     The long-standing but heretofore unfulfilled need for an innovation that overcomes the limitations of the prior art is now met by a new, useful, and nonobvious invention. A first embodiment of the novel apparatus for performing balloon angioplasty and/or stenting includes a guide wire of elongate, flexible construction and a balloon catheter that slideably receives the guide wire. A plurality of longitudinally disposed, circumferentially spaced apart jointed members is formed in the balloon catheter near a distal end thereof. Each joint member of the plurality of joint members has a proximal joint, a distal joint longitudinally spaced apart from the proximal joint, and a middle joint that is substantially half-way between the proximal and distal joints. The jointed members have a position of repose where no bends are formed in any of the joints and the jointed members are therefore substantially flush with the exterior cylindrical wall of the balloon catheter. Each middle joint is displaced radially outwardly, with respect to a longitudinal axis of the balloon catheter, when the distance between its associated proximal and distal joints is reduced, and each middle joint is displaced radially inwardly when that distance is increased. A first displacement means is provided for selectively displacing each of the distal joints toward their associated proximal joints, and a second displacement means is provided for displacing each of the distal joints away from their associated proximal joints to return the jointed members to their position of repose. Both displacement means are under the positive control of a physician and the amount of displacement can be any amount so that the joint members have an infinite number of positions of functional adjustment. 
     A mesh structure of flexible construction has a generally frusto-conical configuration when in repose and is disposed in partially ensleeving relation to the balloon catheter. More particularly, in a first configuration, a first relatively short distal extent of the mesh structure is secured to the balloon catheter distally of the jointed members and a second predetermined proximal extent of the mesh structure ensleeves about half the extent of the jointed members. Thus, the proximal end of the mesh structure is enlarged in diameter when the middle joints are displaced radially outwardly. However, as will become clear as this disclosure continues, the just-described configuration of the mesh structure may be reversed so that the proximal end of the mesh structure is secured to the balloon catheter, proximally of the jointed members, and the distal end thereof is disposed in partially ensleeving relation to the jointed members so that the distal end of the mesh structure is enlarged when the middle joints are displaced radially outwardly. This enables the novel structure to be positioned downstream of a stenosis whether it is positioned in an artery where blood is flowing upwardly or downwardly with respect to the heart. 
     The mesh structure allows blood to flow therethrough and captures and retains emboli produced by a balloon angioplasty and/or stenting procedure when the middle joints are displaced radially outwardly. The mesh structure returns to its position of repose when the middle joints are displaced radially inwardly. 
     Significantly, the jointed members do not deploy automatically under the influence of shape memory when released from the confines of the guide catheter or other catheter which contains them; the deployment is under the control of a physician. Similarly, the return to said position of repose is not a result of the resiliency of the materials of which the balloon and/or stenting catheter and jointed members are made. Instead, the above-mentioned second displacement means is a guide catheter that is displaced by a physician in a proximal-to-distal direction to cause the collapse of the jointed members, it being understood that said guide catheter ensleeves the balloon and/or stenting catheter. 
     A nickel-titanium alloy is the preferred material of which the jointed members are made. Such an alloy is a shape memory alloy, but the memory is insufficient to cause full deployment of the mesh structure when the guide catheter is withdrawn in a distal-to-proximal direction to expose the balloon and the jointed members. Moreover, by employing the first and second displacement means, both of which are under the positive control of a physician, as the positive means for opening and closing said jointed members, respectively, there is no need to use an enhanced shape memory alloy such as a stress-induced martensite alloy as disclosed and broadly claimed in U.S. Pat. No. 5,067,957. Such shape memory alloys are not under the positive control of a physician in that they spring open to their maximum diameter when released from a containment catheter and thus cannot fulfill an important object of this invention. 
     The first displacement means is advantageously provided in the form of a stop means carried by the guide wire near a distal end thereof. The stop means has a breadth greater than the interior diameter of the balloon catheter. Accordingly, an initial displacement of the guide wire in a distal-to-proximal direction, by a physician, causes the stop means to abut a distal end of the balloon catheter and continued displacement causes the middle joints to displace radially outwardly. This enables the physician to open the jointed members to any percentage of full opening as may be desired. 
     The stop means is preferably provided in the form of a bead that is formed on the guide wire near its distal end. The bead has a diameter greater than the internal diameter of the balloon catheter; preferably, the bead diameter is greater than the internal diameter of the distal tip of said balloon catheter. 
     The mesh structure has a generally frusto-conical shape when the middle joint members are radially deployed. A first end of the mesh structure has a first diameter, a second end has a diameter greater than the first diameter, and a generally conical body extends between the first and second ends. The diameter of the second end spans the lumen of the artery within which the novel balloon catheter is deployed so that all emboli produced by the treatment procedure are captured in the mesh. 
     In a second embodiment, the novel jointed members are formed in a catheter, sometimes known as an inner catheter, that is received within the balloon catheter. Due to the small diameter of the inner catheter, it may be enlarged in the region of the jointed members to facilitate their construction. However, if the inner catheter is formed of a suitable material, the enlarged part is not needed. 
     In a third embodiment, the novel jointed members are formed in a guidewire of the type having a coiled outer sheath and an elongate rod slideably mounted therein. The opening and closing of the jointed members is under the positive control of a physician because the physician controls the instantaneous position of the elongate rod. 
     It is a primary object of this invention to provide an emboli collector suitable for use in any part of the body, whether in a region where blood flows upwardly or downwardly with respect to the heart. 
     Another important object is to provide an emboli collector that is opened and closed by positive displacement means under the positive control of a physician so that said opening and closing is not dependent upon the use of special alloys having a shape memory. 
     Still another important object is to provide an emboli collector that may be formed in a balloon catheter, in an inner lumen, or in a guidewire. 
     Another object is to provide an emboli collector having a mechanically simple structure. 
     These and other important objects, features, and advantages of the invention will become apparent as this description proceeds. 
     The invention accordingly comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which: 
     FIG. 1A is a longitudinal sectional view of a blood vessel and a guidewire inserted therewithin; 
     FIG. 1B is a view like that of FIG. 1A, depicting a guide catheter inserted over the guidewire; 
     FIG. 1C is a view like that of FIG. 1B, further depicting a balloon catheter inserted over the guidewire and through the guide catheter; 
     FIG. 1D is a view like that of FIG. 1C, depicting the novel jointed members in their deployed configuration; 
     FIG. 1E is a view like that of FIG. 1D, depicting an angioplasty balloon in its inflated configuration and the novel emboli collector in its open position; 
     FIG. 2 is a view like that of FIG. 1E, depicting the flow of emboli into the novel emboli collector upon deflation of the balloon; 
     FIG. 3 is a view like that of FIG. 1E, depicting emboli collected in the novel emboli collector and depicting the balloon in its fully deflated configuration; 
     FIG. 4 is a view like that of FIG. 1E, depicting the guide catheter in an advanced position to ensleeve the deflated balloon of FIG. 3; 
     FIG. 5 is a view like that of FIG. 1E, depicting further proximal-to-distal displacement of the guide catheter or distal-to-proximal travel of the balloon catheter and hence retraction of the novel emboli collector into the guide catheter; 
     FIG. 6A is a perspective view of a first embodiment of the novel mesh structure when in repose; 
     FIG. 6B is a perspective view of said first embodiment of the novel mesh structure when in an open configuration; 
     FIG. 6C is a perspective view of a second embodiment of the novel mesh structure when in its open configuration; 
     FIG. 6D is a perspective view of a third embodiment of the novel mesh structure when in its open configuration; 
     FIG. 7 is a perspective view depicting the novel mesh structure being held in an open configuration by the novel frame; 
     FIG. 8 is a perspective view of an elongate, flexible guidewire having a stop means formed thereon near a distal end thereof; 
     FIG. 9A is a perspective view of the guide wire of FIG. 8 disposed in ensleeved relation to the novel balloon catheter when the jointed members of the novel frame are slightly deployed; 
     FIG. 9B is a perspective view like that of FIG. 9A when the jointed members are deployed to a greater extent; 
     FIG. 9C is a perspective view like that of FIG. 9A when the jointed members are fully deployed; 
     FIG. 10A is a perspective view of the second embodiment where an inner catheter received within a balloon delivery catheter is enlarged along a predetermined extent to facilitate the formation therein of an increased number of slots and hence an increased number of jointed members; 
     FIG. 10B is a perspective view depicting the embodiment of FIG. 10A when partially deployed; 
     FIG. 10C is a perspective view depicting the embodiment of FIG. 10A when fully deployed; 
     FIG. 10D is a perspective view depicting the environment of the embodiment of FIG. 10A when fully deployed in the iliac or femoral arteries; 
     FIG. 11A is a perspective view of an embodiment similar to that of the FIG. 10A embodiment, where an inner catheter is enlarged at the distal end or tip of the catheter; 
     FIG. 11B is a perspective view depicting the embodiment of FIG. 11A when fully deployed; 
     FIG. 12A is a perspective view depicting the embodiment of FIG. 10A when deployed in an artery and when in its position of repose; 
     FIG. 12B is a perspective view like that of FIG. 12A, depicting said embodiment when partially deployed; 
     FIG. 12C is a perspective view like that of FIG. 12A, depicting said embodiment when fully deployed; 
     FIG. 13A is a longitudinal sectional view of an artery, depicting a third embodiment of the invention where the novel frame is formed in a guidewire, depicting the frame in its position of repose; 
     FIG. 13B is a view like that of FIG. 13A, depicting the novel frame when in its deployed configuration; 
     FIG. 14A is a longitudinal sectional view of a variation of the third embodiment when the jointed members are closed; and 
     FIG. 14B is a view like that of FIG. 14A but with the jointed members deployed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1A-E and  2 , it will there be seen that an exemplary embodiment of the invention is denoted as a whole by the reference numeral  10 . 
     Artery  11  is partially occluded by plaque, calcification, and other debris  12  that builds up on the interior walls of the artery. 
     FIGS. 1A-E provide an animation that concludes with FIG. 1E where inflated balloon  14  is mounted about balloon catheter  16 . Balloon catheter  16  ensleeves elongate guide wire  18 . The distal end of guide wire  18  is denoted  18   a.    
     In the first step of the novel procedure, depicted in FIG. 1A, elongate guidewire  18  is introduced into artery  11 . A bead  42  or other enlargement is formed on said guidewire  18  near distal end or tip  18   a . A guide catheter  19  is then introduced over guidewire  18 , as depicted in FIG.  1 B. 
     Balloon catheter  16  is then introduced into guide catheter  19  as depicted in FIG. 1C; note that balloon  14  is in its deflated condition at this step of the procedure and that said balloon  14  must be positioned outside of guide catheter  16  before it can be inflated. 
     A frame member  20  is formed integrally with balloon catheter  16  near the distal end thereof. A mesh structure  22  is depicted in its operable position in partial ensleeving relation to frame member  20 . Said frame  20  and mesh  22  must also be positioned outside guide catheter  16  so that they may be radially expanded in the manner hereinafter described. FIG. 1D depicts frame  20  when it has been opened by the physician. Note that balloon  14  is still not yet inflated. 
     FIG. 1E depicts balloon  14  when inflated. When so inflated, it physically breaks up plaque  12  into small particles known as emboli. As depicted in FIG. 2, upon deflation of balloon  14 , these small particles or emboli, denoted  24 , are carried away by the bloodstream, thereby reducing the local occlusion. 
     Mesh structure  22  may be made of a molded polymer or a fabric such as Dacron® synthetic fabric, woven sufficiently tight to capture emboli  24  while allowing blood perfusion. Since emboli  24  are much larger in size than red blood cells, they are captured in mesh structure  22 , and they remain captured therewithin when frame  20  is closed and balloon  14 , balloon catheter  16 , guide wire  18 , catheter  19 , frame  20  and mesh structure  22  are withdrawn from artery  11  at the conclusion of the angioplasty and/or stenting procedure. 
     Mesh  22  may be woven with a relatively tight mesh structure at its leading, open end, and with a looser mesh structure at its closed end. The transition between the tight structure and the looser structure would preferably be at a point about mid-length of the mesh structure. The looser mesh structure at the closed end would reduce back pressure and therefore direct blood flow toward the center of mesh  22  so that debris would be captured at the most distal end of mesh  22 . 
     FIG. 3 depicts the novel assembly after balloon  14  has been fully deflated. Note that emboli  24  is captured within mesh structure  22 . 
     FIG. 4 depicts proximal-to-distal advancement of guide catheter  19  relative to balloon catheter  16 . The distal or leading end of guide catheter  19  abuts the proximal or trailing end of frame  20 . 
     FIG. 5 depicts frame  20  as it is withdrawn into guide catheter  19 . The relative proximal-to-distal travel of the guide catheter collapses frame  20  and causes it to close. Note how emboli  24  remain captured within mesh structure  22 . By comparing FIGS. 4 and 5, it should be understood that guide catheter  19  is the positive displacement means for closing frame  20 . Significantly, said positive displacement means is under the control of the physician. 
     Mesh structure  22  may have a cylindrical construction when in repose, as depicted in FIG. 6A, a frusto-conical construction as depicted in FIG. 6B, a parabolic or hyperbolic form as depicted in FIG. 6C, or it may include extension arms for better attachment as depicted in FIG.  6 D. The cylindrical configuration of  6 A is not used if mesh structure  22  is not to be stretched. 
     The small diameter end  28  of mesh structure  22  is secured to balloon catheter  16  by a suitable adhesive or other attachment means. The main body  29  thereof at least partially overlies frame  20  so that opening frame  20  expands the large diameter end  30  thereof so that emboli is captured downstream of the stenotic lesion. When fully opened, large end  30  of mesh  22  should span the artery and conform to the circumference thereof so that no emboli can flow past said mesh  22 . 
     The structure of frame  20  and mesh  22  is perhaps better understood in connection with FIG.  7 . Distal joint  32  and proximal joint  34  are formed in balloon catheter  16 , and three (or more, not shown) elongate slots are formed therebetween to divide the part of balloon catheter  16  between said joints into three elongate sections  36 ,  38 , and  40 . Each of said sections is jointed mid-length thereof as at  36   a ,  38   a , and  40   a  so that when the relative distance between distal and proximal joints  32  and  34  is decreased, said mid-length joints  36   a ,  38   a , and  40   a  are displaced radially outwardly with respect to a longitudinal axis of balloon catheter  16  and when said relative distance is increased, said joints are displaced radially inwardly. Significantly, said decrease and increase in relative distance is under the positive control of the physician. Although jointed members  36 ,  38  and  40  are preferably formed of a nickel-titanium alloy, they do not rely upon shape memory for deployment or retraction. Instead, the physician controls the degree of deployment and contraction. 
     Again, note that the proximal end  30  of mesh  22  is secured to balloon catheter  16  and that main body  29  of said mesh is disposed at least in partial overlying relation to frame  20 . Preferably, proximal end  30  extends slightly proximally of mid-length joints  36   a ,  38   a , and  40   a . This ensures substantially maximum opening of mesh  22  and hence maximum collection of emboli  24 . 
     There are several ways to accomplish the opening of frame  20  and hence of mesh  22 . As depicted in FIG. 8, one way is to provide an enlargement, such as bead  42  near the distal end  18   a  of guide wire  18 . As perhaps best understood in connection with FIGS. 9A,  9 B, and  9 C, bead  42  abuts against the distal end of balloon catheter  16  when guide wire  18  is pulled toward the physician, i.e., when guide wire  18  is displaced in a distal-to-proximal direction as indicated by single-headed directional arrow  44  in said Figures. The mesh structure is not depicted in these Figures to simplify them. Note that the distance between joints  32  and  34  decreases as said guide wire is pulled in the direction of arrow  44 . 
     Maximum emboli collection is achieved when the proximal, open end  30  of mesh  22  is round. It is therefore desirable to increase the number of jointed members to better approximate a circle. FIGS  10 A,  10 B,  10 C, and  10 D disclose an embodiment where four or more jointed members are formed on an enlarged surface of an inner catheter  16   a  for a balloon or stent catheter of the type having a separate inner catheter, so that opening  30  of mesh  22  is close to round; this is the second embodiment of the invention. Inner catheter  16   a  is built up or enlarged as at  17 , and elongate slots  17   a ,  17   b  (depicted in FIG.  10 A),  17   c , and  17   d  (not visible in FIG. 10A) are formed in said enlarged part. This not only increases the number of longitudinal slots that may be formed, it also provides jointed members having rounded profiles as is clear from the drawings. FIG. 10D depicts this embodiment when in use in arteries below the heart level where ability to capture emboli below the lesion is important. Note the substanial roundness of the open end  30  of mesh  22 . The enables it to conform to the lumen of the artery it spans. This embodiment could provide a mesh structure as a middle laminate to inner catheter  16   a  and enlarged body  17 . 
     Significantly, if inner catheter  16   a  is made of an appropriate material, such as aluminum, there is no need to provide enlarged part  17 , i.e., the slots can be formed in an inner catheter  16   a  having no enlarged section. 
     FIGS. 11A and 11B show a variation of the embodiment of FIGS. 10A-D when the enlarged surface is molded over the distal end of inner catheter  16   a  to form the tip of the catheter assembly. FIG. 11A depicts this embodiment when frame  20  is in repose at the distal tip of inner catheter  16   a . Each jointed member has a profile like that of an isosceles triangle so that open end  30  of mesh  22  has a larger diameter than closed end  28  thereof even before the distance between the distal and proximal joints  32 ,  34  is decreased. This embodiment could also provide a mesh structure as a middle laminate to inner catheter  16   a  and enlarge body  17 . 
     FIGS. 12A-C depict the embodiment of FIGS. 10A-D when disposed within an artery  11 . FIGS. 12A depicts frame  20  in its closed position. FIG. 12B depicts said frame in its partially deloyed configuration, and the jointed members are fully deployed in FIG.  12 C. Note in FIG. 12C how frame  20  completely spans the artery so that all emboli will be captured within mesh  22  (not depicted). 
     In a third embodiment of the invention, depicted in FIGS. 13A-B, a modified elongate guide wire  40  of the type having a coiled, flexible outer structure  39   a  that slideably receives an elongate inner rod  44  therein is used. The modification includes two additional segments brazed onto the distal end  41  of guidewire  40 . The first segement, denoted  20   a , is formed of a nickel-titanium alloy and includes a plurality of jointed members. The second segment, denoted  39   b , is brazed onto the distal end of first segment  20   a  and is formed of the same material as coiled, flexible outer structure  39   b . Inner rod  44  is secured to the distal end of slotted segment  20   a  as at  48 . Accordingly, axial retraction of inner rod  44  provides a first positive displacement means that deploys the joined members  20   a  as indicated in FIG.  13 B and opens mesh  22  to enable emboli capture. Balloon or guide catheter  16  (FIG. 13B) provides a second positive displacement means when it is displaced in a proximal-to-distal direction, as in the previous embodiments, to collapse the joined members when the angioplasty procedure is over. Alternatively, inner rod  44  provides a second positive displacement means that accomplishes the closing of the jointed members and hence of the mesh structure when the axial retraction of said inner rod  44  is reversed. 
     Exhibit B attached hereto indicates how each of the original paragraphs is amended to produce the paragraphs as rewritten. In Exhibit B, underscored terms are added and bracketed terms are deleted. 
     A variation of the third embodiment is depicted in FIGS. 14A and 14B, and is denoted  40   a  as a whole. Guidewire  40   a  includes an outer structure  42   a  made of a nickel-titanium alloy and an inner core  44   a  slideably received therewithin. An elongate slot  50  is formed in outer structure  42   a  to allow longitudinal movement of pin  52  that extends diametrically through annular bushing  54  to slideably secure said bushing  54  to said outer structure  42   a . A similar bushing  56  encircles said outer structure  42   a  and is interconnected to bushing  54  by a plurality of jointed members, collectively denoted  58 . Jointed members  58  are also preferably made of a nickel-titanium alloy. However, their deployment and closing is under the positive control of inner rod  44   a  as understood upon comparison of FIGS. 14A and 14B. Mesh  22  is in its position of repose in FIG.  14 A and is in its emboli-collecting position in FIG.  14 B. 
     In all embodiments, mesh  22  may be impregnated with an anti-clotting compound such as Heprin® to further enhance its utility. 
     The novel apparatus is not limited to balloon angioplasty procedures. It has utility in connection with any procedure where blood clots are broken into smaller pieces, including any surgical procedure in which a plaque-filled vessel is clamped. 
     This invention represents a major breakthrough in the art of balloon angioplasty and/or stenting. Being drawn to a pioneering invention, the claims that follow are entitled, as a matter of law, to broad interpretation to protect the heart or essence of the invention from piracy. 
     It will thus be seen that the objects set forth above, and those made apparent from the foregoing description, are efficiently attained. Since certain changes may be made in the foregoing construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing construction or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
     It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention that, as a matter of language, might be said to fall therebetween. 
     Now that the invention has been described,