Abstract:
A device for collapsing a balloon in the vasculature of a patient after an angioplasty procedure includes a balloon and at least one elastomeric member that is attached to the inner surface of the balloon at a plurality of attachment points. Preferably, the elastomeric member is an annular band that will stretch during balloon inflation. Consequently, when the balloon is deflated, the elastomeric member pulls on the balloon at its attachment points to return the balloon to a predetermined configuration, wherein the balloon collapses inwardly onto itself for subsequent removal of the balloon from the vessel.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention pertains generally to balloon devices which are used in interventional medical procedures. More particularly, the present invention pertains to angioplasty balloon devices which collapse a balloon during deflation for subsequent removal from the vasculature of a patient. The present invention particularly, though not exclusively, pertains to elastomeric members which are incorporated to collapse the balloon in a uniform and predictable manner during a balloon deflation.  
         BACKGROUND OF THE INVENTION  
         [0002]    Many modern surgical techniques have been developed which are employed to alleviate or obviate the stenoses that are formed when plaque builds up in a patient&#39;s vessels. For example, several balloon angioplasty devices have been proposed for insertion into a vessel to compress the stenosis and widen the passageway through the vessel. In several respects, balloon angioplasty devices afford numerous advantages over alternative methods. Foremost among these advantages is that open-heart bypass surgery can often be avoided by using angioplasty surgical techniques to relieve stenoses in the vessels that supply blood to the heart. For obvious reasons, it is preferable to avoid open heart surgery whenever possible, because such surgery, as is well known, is invasive and can consequently require significant post-operative recovery time. Accordingly, rather than many alternative procedures, it is often preferable to use relatively simpler angioplasty surgical procedures, when such procedures are feasible. Importantly, angioplasty procedures can be performed in the peripheral vessels of a patient, as well as in the vessels that supply blood to the heart.  
           [0003]    In an angioplasty surgical procedure, the balloon of a balloon catheter is initially in a deflated configuration as it is advanced through the vasculature into a vessel and positioned next to the stenosis that is to be treated. Once the balloon has been properly positioned, fluid is infused into the balloon to expand the balloon. As the balloon expands, it dilates the stenosis in the lumen of the vessel and compresses the plaque. This causes the plaque to break up or flatten out against the vessel wall. Once the stenosis has been compressed, however, the balloon needs to be deflated. In its deflated configuration, it is then either withdrawn from the vessel or placed across another stenosis, as necessary, to restore normal blood flow through the vessel.  
           [0004]    During the deflation of a balloon, after an angioplasty procedure and prior to its removal from the vessel, it is desirable that the balloon be deflated into a predictable configuration as evenly and as compactly as practicable to facilitate removal of the balloon through tortuous passageways of the vessel. Several polymers which are desirable for use in balloon angioplasty catheters, because of their strength, such as polyethylene terephthalate and polyethylene naphthalate, are well known for poor refold characteristics.  
           [0005]    In light of the above, it is an object of the present invention to provide a device that is useful for collapsing a balloon into a compact pleated cross-sectional configuration during balloon deflation to facilitate removal of the balloon from a patient&#39;s body. Another object of the present invention is to provide a device that is useful for collapsing a balloon in a uniform and predictable manner during balloon deflation. Yet another object of the present invention is to provide a device which is relatively simple to manufacture, easy to use, and comparatively cost effective.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention is a device for predictably collapsing a balloon into a desired reconfiguration during its deflation. For the present invention, the device includes the balloon and at least one elastomeric member that is attached to the inside surface of the balloon at predetermined attachment points. The balloon, defining a longitudinal axis, can be any angioplasty balloon known in the art. The device is particularly effective, however, in construction with balloon materials which, due to their polymeric structure, resist heat setting and exhibit poor refold.  
           [0007]    As contemplated for the present invention, it is preferable that a plurality of elastomeric members be attached to the inner surface of the balloon to influence deflation of the balloon. In particular, each elastomeric member is a generally annular-shaped band having an unstretched diameter, D m . Further, each elastomeric band is attached to the inner surface of the balloon at a plurality of attachment points and is centered on the axis of the balloon. For example, each elastomeric member can be attached to the inner surface of the balloon at multiple separate attachment points by any means well known in the art, such as by gluing, bonding with anaerobic adhesive, heat bonding and laser welding.  
           [0008]    When more than one elastomeric members are used for the present invention, the individual elastomeric members can be positioned at predetermined distances along the axis of the balloon. The consequence of this is that the attachments points of each elastomeric member are positioned in respective planes that are perpendicular to the axis of the balloon and substantially parallel to each other. Thus, corresponding attachment points on respective elastomeric members are spaced apart from each other. Preferably, these attachment points are aligned with each other and located at predetermined distances from each other in an axial direction. The predetermined distance between each elastomeric member may vary depending upon the particular need. Also, the attachment points need not be axially aligned and, instead, can be helically aligned along the length of the balloon axis.  
           [0009]    In operation, the initially deflated balloon is positioned in a vessel of the patient and is then infused with fluid to perform an angioplasty procedure. In this surgical procedure, the inflating balloon may pull on the unstressed elastomeric members at the respective attachment points. During balloon inflation, the elastomeric members may stretch and expand away from the axis. Because of the elastic nature of the elastomeric members, however, each elastomeric member is biased in its stressed configuration to return to its unstressed configuration. Thus, once the fluid begins to be removed from the balloon, the elastomeric members may pull on the balloon at their respective attachment points. Since corresponding attachment points on respective elastomeric members are axially aligned with each other, this pulling action on the balloon at these corresponding attachment points may create fold lines in the axial direction. As a result, the deflating balloon may fold onto itself along the axis to form a pleated cross-sectional shape. Once the balloon is deflated and the elastomeric members have returned to their unstressed, substantially ring-shaped form, the balloon catheter may then be removed from the vessel. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:  
         [0011]    [0011]FIG. 1 is a perspective view of the present invention, shown positioned in the vasculature of a patient, with the balloon in its deflated configuration;  
         [0012]    [0012]FIG. 2A is a perspective view of the present invention, when the balloon is inflated, and the elastomeric members, shown in phantom, are in their stressed configurations;  
         [0013]    [0013]FIG. 2B is a perspective view of the present invention, when the balloon is deflated, and the elastomeric members, shown in phantom, are in their unstressed configurations;  
         [0014]    [0014]FIG. 3A is a cross-sectional view of the elastomeric member attached to the balloon as seen along the lines  3 A- 3 A in FIG. 2A; and  
         [0015]    [0015]FIG. 3B is a cross-section view of the elastomeric member attached to the balloon, with the balloon in its deflated configuration as would be seen along the lines  3 B- 3 B in FIG. 2B.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    Referring initially to FIG. 1, an angioplasty balloon in accordance with this present invention is shown and is generally designated  10 . The balloon  10  is shown inserted into a vessel  12  of a patient  14  and positioned adjacent to a stenosis  16  in the vessel  12 . As is also shown, balloon  10  is connected in fluid communication with a hollow catheter tube  18  which, in turn, is connected in fluid communication with a fluid source  20 . If required, the balloon  10 , along with the catheter tube  18 , can be inserted into the patient  14  through an insertion catheter  22 . The balloon  10  is preferably made of any suitable angioplasty balloon material, such as polyethylene terephthalate or polyethylene naphthalate.  
         [0017]    The present invention can perhaps be best appreciated by cross-referencing FIGS. 2A and 2B. In contrast to each other, FIG. 2A shows elastomeric members  24   a - e  in their stressed configurations, with balloon  10  inflated. FIG. 2B, on the other hand, shows elastomeric members  24   a - e  in their unstressed configuration, with balloon  10  deflated. As shown in FIGS. 2A and 2B, the elastomeric members  24   a - e  are attached to an inner surface  23  of the balloon  10 . In detail, the balloon  10  has a midsection  25  defining a longitudinal axis  26  and end portions  27   a  and  27   b  that are attached to the midsection  25 . When balloon  10  is inflated (FIG. 2A), the midsection  25  of the balloon  10  is substantially cylindrical-shaped and the ends  27   a - b  are substantially conical-shaped. Specifically, when inflated, the ends  27   a - b  have a diameter  28  that decreases in a direction away from the midsection  25 . FIGS. 2A and 2B show the balloon  10  with five elastomeric members  24   a - e  attached to the inner surface  23  of the balloon  10 . In particular, two respective elastomeric members  24   d - e  are shown in the corresponding conical-shaped end portions  27   a - b.  It is to be appreciated that these five elastomeric members  24   a - e  are only exemplary, for there may be either fewer or more elastomeric members  24  attached to the balloon  10  as desired.  
         [0018]    As shown in FIGS. 2A and 2B, each elastomeric member  24   a - e,  is positioned around the axis  26 , and is attached to the inner surface  23  of the balloon  10  at a plurality of attachment points  30   a - d.  As shown, each elastomeric member  24   a - e  is attached to the inner surface  23  of the balloon  10  at four attachment points  30   a - d,  by any means well known in the art. These four attachment points  30   a - d,  however, are only exemplary. It would be appreciated that each elastomeric member  24  may be attached to the inner surface  23  of the balloon  10  at either fewer or more attachment points  30  as desired. It can also be appreciated that the attachments could be made asymmetrically or from an asymmetric folded balloon shape, if desired. In any case, these attachment points  30   a - d  between one of the elastomeric members  24  and the balloon  10  can perhaps be best seen in FIGS. 3A and 3B.  
         [0019]    As shown in FIGS. 3A and 3B, the elastomeric member  24  is attached to the inner surface  23  of the balloon  10  at four attachment points  30   a - d.  With four attachment points  30   a - d,  each attachment point  30  is azimuthally distanced from adjacent attachment points  30  by approximately ninety degrees (90°). FIG. 3A shows an azimuthal angle, β, between attachment points  30   c  and  30   d  that is approximately ninety degrees (90°). On the other hand, when an elastomeric member  24  is attached to the balloon  10  at three attachment points  30  (not shown), each attachment point  30  is azimuthally distanced from adjacent attachment points  30  by approximately one hundred twenty degrees (120°).  
         [0020]    Referring back to FIGS. 2A and 2B, each elastomeric member  24   a - e  is shown attached to the balloon  10  at its respective attachment points  30   a - d.  In order for the elastomeric members  24   a - e  to act in concert to collapse the balloon  10  during balloon deflation, it is preferable that corresponding attachment points  30   a - d  on respective elastomeric members  24   a - e,  as shown in FIG. 2A, are spaced apart from each other and are axially aligned at a predetermined linear distance  32   a - d  in the axial direction, as shown in FIG. 2B. For the present invention, these predetermined distances  32   a - d  between elastomeric members  24   a - e  may vary depending upon the particular need.  
         [0021]    For the present invention, each elastomeric member  24  will move between a stressed configuration, as shown in FIGS. 2A and 3A, and an unstressed configuration, as shown in FIGS. 2B and 3B, depending on whether balloon  10  is inflated or deflated. Specifically, when balloon  10  is inflated, and when the elastomeric members  24   a - e  are in their stressed configurations (FIGS. 2A and 3A), balloon  10  will pull on the elastomeric members  24   a - e  at their respective attachment points  30   a - d.  As a result, when attached at four attachment points  30   a - d,  each elastomeric member  24  expands and assumes a substantially square or rectangular shape. This can be seen in FIGS. 2A and 3A. The inflated balloon  10  has a substantially circular cross-sectional shape with a diameter  34  (D b ), as shown in FIG. 3A. Furthermore, when the balloon  10  is inflated, the diameter  34  (D b ) of the inflated balloon  10 , as shown in FIG. 3A, is greater than the diameter  36  (D m ) of the unstressed elastomeric member  24 , as shown in FIG. 3B. More specifically, the diameter  34  of the inflated balloon  10  is approximately eight to twelve times greater than the diameter  36  of the elastomeric member  24  in its unstressed configuration. For example, the diameter  34  of the inflated balloon  10  can be ten times greater than the diameter  36  of the elastomeric member  24  (D b =10 D m ).  
         [0022]    When balloon  10  is deflated, and the elastomeric members  24   a - e  return to their unstressed configurations (FIGS. 2B and 3B), each elastomeric member  24  may be substantially ring-shaped and may have an unstretched diameter  36 , D m , as shown in FIG. 3B. Each elastomeric member  24  may pull on the balloon  10  at its respective attachment points  30   a - d  to return the elastomeric member  24  to its unstressed configuration. Further, when the elastomeric members  24   a - e  pull at their respective attachment points  30   a - d,  the balloon  10  may fold over at the attachment points  30   a - d  and collapse onto itself. As a result, the balloon  10 , in its deflated configuration, has a pleated cross-sectional shape, as shown in FIG. 3B.  
         [0023]    Since corresponding attachment points  30   a - d  are axially aligned with each other, as shown in FIG. 2A, as the elastomeric members  24   a - e  pull the balloon  10  toward the axis  26 , the balloon  10  may fold at fold lines  38  created by the axially aligned attachment points  30 . (The fold lines  38   a  and  38   b  shown in FIGS. 2A and 2B are only exemplary.) As shown, these fold lines  38  are, preferably, oriented substantially parallel to the axis  26 . Alternatively, the fold lines  38  could have a helical orientation in relation to the axis  26 . In either case, these fold lines  38  assist the balloon  10  in predictably collapsing onto the axis  26 , and into a desired reconfiguration after deflation.  
       Operation  
       [0024]    In the operation of the present invention, balloon  10  is first in a deflated configuration, as shown in FIG. 2B. As shown, when the balloon  10  is deflated, the elastomeric members  24   a - e  are in their unstressed configurations. Deflated balloon  10  can then be inserted through the insertion catheter  22  and advanced into the patient  14  until the balloon  10  is positioned adjacent the stenosis  16 , as seen in FIG. 1. Fluid from fluid source  20  can then be infused into balloon  10  through catheter tube  18  to inflate the balloon  10  in accordance with appropriate angioplasty procedures.  
         [0025]    Balloon  10 , when it is infused with fluid from fluid source  20 , presses against the stenosis  16  to expand the lumen of the patient  14 . Meanwhile, as the balloon  10  is being inflated, the elastomeric members  24   a - e  are being pulled by the inflating balloon  10  at their respective attachment points  30   a - d.  Consequently, each elastomeric member  24  moves from its unstressed configuration to its stressed configuration. In more detail, each elastomeric member  24  expands away to assume a substantially square or rectangular shape, when attached to the balloon  10  at four attachment points  30   a - d.    
         [0026]    In the stressed configuration, each elastomeric member  24  is biased toward its unstressed configuration to collapse the balloon  10  inwardly toward axis  26 . Accordingly, when fluid is withdrawn from balloon  10 , each elastomeric member  24  pulls the balloon  10  at its respective attachment points  30   a - d  to return balloon  10  to its deflated configuration, as shown in FIGS. 2B and 3B. In more detail, since corresponding attachment points  30   a - d  on respective elastomeric members  24   a - e  are axially aligned at predetermined distances  32   a - d  in the axial direction, the elastomeric members  24   a - e  pull at their respective attachment points  30   a - d  and create fold lines  38  on the balloon  10  where the balloon  10  folds over. The fold lines  38  are initially created, in large part, as a result of the elastomeric members  24   d  and  24   e  pulling on respective attachment points  30   a - d  in respective end portions  27   a  and  27   b.  As a result of the elastomeric members  24   a - e  pulling on the attachment points  30   a - d,  the balloon  10  will collapse at the fold lines  38  onto itself and fold onto the axis  26 . In its deflated configuration, balloon  10  may be subsequently removed from the vessel  12  of the patient  14 .  
         [0027]    Although the present invention has been described above in accordance with an angioplasty procedure performed in the vessel  12  of a patient  14 , it will be appreciated that the balloon  10  can be inserted into the vessel  12  of the patient  14  to perform a different surgical procedure. For example, the balloon  10  can be inserted into an air passageway of the patient  14  to widen the passageway. Accordingly, the present invention is intended to have universal application in surgical procedures performed on the patient  14 .  
         [0028]    While the particular Device and Method for Collapsing an Angioplasty Balloon as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.