WO2017199155A1

WO2017199155A1 - Variable size balloon catheter for vessel treatment

Info

Publication number: WO2017199155A1
Application number: PCT/IB2017/052849
Authority: WO
Inventors: Ronald Jay Solar; Glen Lieber
Original assignee: Thermopeutix, Inc.
Priority date: 2016-05-15
Filing date: 2017-05-15
Publication date: 2017-11-23

Abstract

Localized delivery of a therapeutic or diagnostic agent within a vessel, providing for adjustability of the length and diameter of the treatment area and for selective treating of an area without adversely affecting other parts of the body. Systems and methods include a catheter having an inner elongated element, an outer elongated element positioned external to and coaxially with respect to the inner elongated element, wherein the inner elongated element is movable with respect to the outer elongated element, and a balloon attached to the inner and outer elongated elements, wherein a balloon proximal end is attached to the outer elongated element distal end and a balloon distal end is attached to the inner elongated element wherein in a pre-deployment configuration the balloon is positioned within an outer elongated element lumen, with a balloon inner surface adjacent to an inner surface of the outer elongated element.

Description

VARIABLE SIZE BALLOON CATHETER FOR VESSEL TREATMENT

FIELD AND BACKGROUND

[001] The present invention relates to systems and methods for treatment of vessels, including delivery of therapeutic or diagnostic agents, wherein the systems provide for varying lengths and diameters of the treatment area. The systems and methods herein are designed for selective treating of an area without adversely affecting other parts of the body.

[002] Methods and devices designed to provide drugs to a vessel, include, for example, the use of drug-coated balloons, such as disclosed in US Patent Number 5,954,706 to Sahatjian, for example. Such devices include a catheter with an expandable portion, wherein at least a portion of the exterior surface of the expandable portion is defined by a coating of hydrogel polymer. Incorporated within the hydrogel polymer is a solution of a preselected drug to be delivered to the tissue or plaque. Disadvantages of such devices include limitations on the length and diameter of the treatment area as defined by the predetermined length and diameter of the expandable portion, inability to position the balloon in tight or tortuous vascular anatomy, and loss of drug during transit of the balloon to the treatment area. To prevent loss of drug during transit of the balloon to the treatment area, some devices include an outer sheath or other means to cover the balloon during transit. For example, US Patent Number 8,617, 104 to Yribarren et al discloses maintaining the balloon within a chamber defined by an outer shaft member and inner shaft member during transit, and retracting the outer shaft member to expose the balloon to the treatment area. However, in treatment areas that are located in narrowed or tortuous vascular anatomy, it may be difficult to position the balloon with such a design.

[003] Another device is disclosed in US Patent Publication 2007/0078433 to Schwager et al. This device includes a balloon catheter having a predetermined inflow angle of medication. A first and second expandable balloon are positioned on the catheter, with a treatment zone therebetween. Disadvantages of devices such as the ones disclosed in the above-referenced publications include limitations on the length of the treatment area as predetermined by the distance between the expandable members.

[004] Devices disclosed in US Patent Application Publication Number 2005/0059930 to Garrison et al., and in US Patent Number 8,721 ,592 to Solar et al. include catheter systems with at least two expandable occluding elements that are used to create a localized site for administration of agents. The catheters are slidable with respect to one another to vary the space between the balloons as desired. However, in certain clinical applications, particularly in treating blood vessels, there may be small collateral vessels located within the desired drug treatment zone, and this may result in leakage of the agent from the zone. There is thus a need for, and it would be highly advantageous to have, a system and method for localized drug delivery within a vessel, with adjustability of the length and diameter of the treatment area, with means for preventing loss of drug during transit to the treatment area, and with ability to treat very narrowed and tortuous vascular anatomy.

SUMMARY

[005] There is provided, in accordance with embodiments of the present invention, a catheter system having an inner elongated element and an outer elongated element positioned coaxially with respect to the inner elongated element. The outer elongated element has an outer elongated element proximal end and an outer elongated element distal end, with an outer elongated element lumen extending from the outer elongated element proximal end to the outer elongated element distal end. The inner elongated element has an inner elongated element proximal end and an inner elongated element distal end. The inner elongated element may optionally include an inner elongated element lumen, and is movable with respect to the outer elongated element. A balloon, having a balloon proximal end and a balloon distal end, is appended or attached to the inner and outer elongated elements. The balloon proximal end is appended or attached to the outer elongated element distal end. In accordance with further features of the present invention, the balloon distal end is appended or attached to the inner elongated element at one of various locations. The system may further include a treatment or diagnostic agent disposed on the outer surface of the balloon. The inner elongated element may further include a guidewire positioned therethrough, or the system may include a distal rail element at the distal end of either the outer elongated element or inner elongated element, wherein the distal rail element is slidable over a guidewire. A hub may be included at the outer elongated element proximal end for introducing inflation fluid into the outer elongated element lumen.

[006] In accordance with further features of the present invention, the catheter system has a pre-deployment configuration wherein the balloon is positioned within the outer elongated element lumen with a balloon inner surface adjacent to an inner surface of the lumen wall of the outer elongated element, and with the balloon distal end positioned proximal to the balloon proximal end. That is, the balloon may initially be positioned in an "inside-out" configuration. Introduction of inflation fluid into the outer elongated element lumen causes the balloon to begin to unroll and evert distally from the outer elongated element lumen into a desired treatment zone of the vessel. Such eversion of the balloon may be achieved or assisted by advancement of the inner elongated element. A stopping mechanism is provided to stop the eversion at a desired point to provide a preferred length of the balloon. With the eversion halted at the desired location, continued introduction of inflation fluid into the outer elongated element lumen will cause the balloon to expand radially to a desired diameter.

[007] In accordance with an additional embodiment of the present invention, the inner elongated element has an inner elongated element lumen extending from inner elongated element proximal end to inner elongated element distal end. The balloon distal end is bonded or otherwise attached to the inner elongated element distal end. In a pre-deployment configuration, wherein the balloon is positioned within the outer elongated element lumen with a balloon inner surface adjacent to an inner surface of the lumen wall of the outer elongated element, and the balloon distal end positioned proximal to the balloon proximal end, the system further includes an introducing element within the inner elongated element lumen. The introducing element extends proximally from the outer elongated element distal end to and beyond the inner elongated element proximal end, and may include an introducing element lumen adapted to accommodate a moveable guidewire. The catheter unit is advanced over the moveable guidewire to the treatment zone, and prior to deployment of the balloon, the introducing element is removed from the inner elongated element.

[008] In accordance with another embodiment of the present invention, initial eversion of the balloon provides for occlusion of the blood vessel at a location proximal to the treatment zone, and further eversion of the balloon will progress with the balloon unrolling while maintaining contact with the wall of the blood vessel. The unrolling of the balloon allows it to follow the contour of the vessel/luminal wall. Delivering a balloon to a target location in this manner will avoid shear forces produced by delivery of prior art balloon catheters which can damage the inner walls of a blood vessel by pushing of the balloon through the lesion. These shear forces may scrape the drug off the balloon, may cause damage to the lining of the vessel wall (e.g. scraping of endothelial cells from the intima), or may cause embolization. Use of the catheter unit of the present invention avoids these problems.

[009] In accordance with another embodiment of the present invention, the inner elongated element has an inner elongated element lumen extending from the inner elongated element proximal end to the inner elongated element distal end. The balloon distal end is bonded or otherwise attached to the inner elongated element at a location proximal to the inner elongated element distal end. Eversion of the balloon from the outer elongated element will advance the inner elongated element distally into the vessel. A guidewire may optionally be placed into the inner elongated element lumen. Attaching the balloon to a point which is proximal to the inner elongated element distal end results in a design wherein the inner elongated element will extend distally into the vessel, beyond the balloon, as the balloon is everting out in partial and full deployment. If a guidewire is placed within the inner elongated element, this would provide for a device which does not require a separate guidewire lumen via an introducing element, for example, which could help maintain a small profile for the device. A guidewire placed within an inner elongated element such as the one described herein could also provide access through a lesion, distal to the treatment site. In some embodiments, the inner elongated element is solid. If the balloon is attached to the inner elongated element proximal to the inner elongated element distal end, the extension of the inner elongated element distally past the balloon could help facilitate crossing of a tight lesion. There may be additional advantages to different locations of bonding of the balloon onto the inner elongated element, with or without an inner elongated element lumen.

[0010] In accordance with yet an additional embodiment of the present invention, there is provided a system having an inner elongated element and an outer elongated element positioned coaxially with respect to the inner elongated element. The outer elongated element has an outer elongated element proximal end and an outer elongated element distal end, with an outer elongated element lumen extending from the outer elongated element proximal end to the outer elongated element distal end. The inner elongated element has an inner elongated element proximal end and an inner elongated element distal end, with an inner elongated element lumen extending from the inner elongated element proximal end to the inner elongated element distal end, and the inner elongated element is movable with respect to the outer elongated element. A balloon, having a balloon proximal end and a balloon distal end, is appended or attached to the inner and outer elongated elements. The balloon proximal end is appended or attached to the outer elongated element distal end. In accordance with further features of the present invention, the balloon distal end is appended or attached to the inner elongated element at one of various locations. The system may include a treatment or diagnostic agent disposed on the outer surface of the balloon. The system further may include a supply element coaxial to the outer elongated element, the supply element having an inlet port at a distal end thereof, wherein the inlet port is proximal to the outer elongated element distal end.

[0011] In accordance with an additional embodiment of the present invention, there is provided a method for treating a vessel. The method includes introducing a catheter unit having an inner elongated element and an outer elongated element positioned coaxially with respect to the inner elongated element, and a balloon attached to the inner and outer elongated elements, wherein a balloon proximal end is attached to an outer elongated element distal end, the balloon distal end is attached to the inner elongated element, and the catheter unit has a pre-deployment configuration wherein the balloon is positioned within an outer elongated element lumen with a balloon inner surface adjacent to an inner surface of a lumen wall of the outer elongated element, and the balloon distal end is positioned proximal to the balloon proximal end. Introduction of inflation fluid into the outer elongated element lumen causes the balloon to begin to unroll and evert distally from the outer elongated element lumen into the desired treatment zone of the vessel. The method may further include everting the balloon to variable lengths and diameters, delivery of a therapeutic or diagnostic agent on the outer surface of the balloon, and expanding the diameter of the balloon to dilate a narrowed or occluded segment of a vessel.

[0012] It should be readily apparent that various combinations of the features disclosed herein are possible and that any of the embodiments may include any of the features in any combination.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the embodiments of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. [0015] In the drawings:

[0016] FIG. 1A is a schematic illustration of a catheter unit in accordance with embodiments of the present invention, having an outer elongated element, an inner elongated element, a balloon element positioned thereon, and a hub for introduction of an inflation solution;

[0017] FIG. 1 B is a schematic illustration of the catheter unit of FIG. l A in a pre- deployment configuration wherein the balloon is positioned within the lumen of the outer elongated element;

[0018] FIG. 1 C is a schematic illustration of the catheter unit of FIG. 1A with the balloon deployed to a desired configuration;

[0019] FIG. 2 is a schematic illustration of the catheter unit of FIG. 1A in accordance with yet another embodiment of the present invention, wherein the system has a distal rail at the distal end of the inner elongated element to accommodate a guidewire;

[0020] FIG. 3 is a schematic illustration of a catheter unit in accordance with embodiments of the present invention wherein the inner elongated element includes a lumen therethrough and an introducing element is positioned within the lumen of the inner elongated element;

[0021] FIGS.4A-4C are schematic illustrations of steps of a method of treating a segment of a vessel using a catheter unit, in accordance with embodiments of the present invention;

[0022] FIG. 5 is an illustration of a system having a catheter with a supply lumen, in accordance with another embodiment of the present invention; and

[0023] FIGS.6A-6C are schematic illustrations of steps of a method of treating a segment of a vessel using a catheter unit, in accordance with additional embodiments of the present invention.

[0024] It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components may be included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function.

DETAILED DESCRIPTION

[0025] The present invention is of systems and methods which can be used for treatment of a vessel including delivery of a therapeutic or diagnostic agent into the vessel. As will be apparent to one of skill in the art, the invention can also be used to cross stenotic segments in a vessel. For the purposes of the present invention, the term "delivery substance" is used to include any therapeutic or diagnostic agent which may be delivered into the vessel, including but not limited to medications, saline, contrast media, sealing agents, etc. The present invention provides a device wherein a user can selectively adjust the length and diameter of a delivery portion of the catheter and can control the period of exposure of the delivery substance at the selected location while minimizing exposure of the delivery substance to unwanted areas.

[0026] The principles and operation of systems and methods according to the present invention may be better understood with reference to the drawings and accompanying descriptions.

[0027] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0028] Reference is now made to FIGS. 1A and 1 B, which are schematic illustrations of a catheter unit 10 in accordance with embodiments of the present invention. Catheter unit 10 includes a catheter body 12 which includes an outer elongated element 20 having an outer elongated element lumen 21 therethrough. Catheter body 12 further includes an inner elongated element 22. Inner elongated element 22 is preferably an elongated tubular member, extending through an entire length of catheter body 12, and has an inner elongated element proximal end 16 and an inner elongated element distal end 18. In some embodiments, inner elongated element 22 is a solid element, and in some embodiments inner elongated element 22 has an inner elongated element lumen 23 therethrough and a guidewire exit port 24 at or near inner elongated element distal end 18, as shown in FIGS. 4A- 4C. Inner elongated element lumen 23 and guidewire exit port 24 are configured for placement of a guidewire therethrough, as will be explained further hereinbelow, but can also be used for perfusion, or exchange of different sized guidewires, for example. In some embodiments, inner elongated element lumen 23 and guidewire exit port 24 are not included, and the profile of inner elongated element 22 may be reduced. Outer elongated element 20 is preferably an elongated tubular member having an outer elongated element proximal end 25 and an outer elongated element distal end 27. Outer elongated element 20 is positioned externally and coaxially with respect to inner elongated element 22, and inner elongated element 22 is movable with respect to outer elongated element 20. Catheter body 12 further includes an inflatable balloon 28, having a balloon proximal end 29 and a balloon distal end 30, appended or otherwise attached to the inner elongated element 22 and outer elongated element 20. Designation as "proximal" and "distal" with respect to balloon 28 is defined in accordance with the positions of balloon 28 upon full deployment. However, prior to introduction of catheter unit 10 and during deployment of balloon 28, the relative positions of balloon proximal end 29 and balloon distal end 30 will change (i.e., the balloon will be "inside-out"), as will be described hereinbelow. Balloon proximal end 29 is appended or attached to outer elongated element distal end 27 at a proximal attachment point 14. The term "attached" will be used herein to designate any form of attachment, including temporary or permanent attachment, using any suitable method. In accordance with further features of the present invention, the balloon distal end 30 is attached to inner elongated element 22 at one of various locations. For example, in one embodiment, as shown in Figs. 1A-1 C, balloon distal end 30 is attached to inner elongated element distal end 18 at a distal attachment point 15. In other embodiments, balloon distal end 30 is attached to inner elongated element 22 at a point which is proximal to inner elongated element distal end 18, as shown in FIGS. 4A-4C.

[0029] Catheter unit 10 further includes a hub 32 at outer elongated element proximal end 25 for introducing inflation fluid into outer elongated element lumen 21 , as indicated by arrows 70 in Fig. 1 C. Catheter unit 10 may further include a treatment or diagnostic agent disposed on a balloon outer surface 31 . Again, the designation of "outer" and "inner" with respect to balloon 28 is defined in accordance with the positions of balloon 28 upon full deployment. However, prior to introduction of catheter unit 10 and during deployment of balloon 28, the relative positions of balloon outer surface 31 and a balloon inner surface 1 1 will change, as will be described hereinbelow.

[0030] Figs. 1 A-1 C illustrate catheter unit 10 in various stages of deployment of balloon 28, in accordance with features of the present invention. Catheter unit 10 has a pre-deployment configuration as illustrated in Fig. 1 B, wherein balloon 28 is positioned within outer elongated element lumen 21 with balloon inner surface 1 1 adjacent to an outer elongated element wall inner surface 19, and balloon distal end 30 positioned proximal to balloon proximal end 29. In this embodiment, balloon distal end 30 is attached to inner elongated element distal end 18 at distal attachment point 15. Introduction of inflation fluid into outer elongated element lumen 21 from hub 32, as indicated by arrows 70 in Fig. 1 C, causes balloon 28 to begin to unroll and evert distally past outer elongated element lumen 21 into a desired treatment zone of the vessel. Such eversion of balloon 28 may be achieved or assisted by advancement of inner elongated element 22, wherein the advancement may be done simultaneously with the introduction of the inflation fluid. A stopping mechanism 33 is provided at inner elongated element distal end 16 to stop the eversion at a desired point, in order to provide a preferred length of balloon 28. Stopping mechanism 33 may include, for example, a clamp or high-friction valve as known in the art, and is designed to prevent inner elongated element 22 from extending too far distally. Alternatively, a desired length of balloon eversion may be achieved by manually holding inner elongated element 22 stationary with respect to outer elongated element 20. With the eversion halted at the desired location, continued introduction of inflation fluid into the outer elongated element lumen 21 will cause the balloon to expand radially to a desired diameter. Figure 1 A shows full deployment and inflation of balloon 28 in accordance with an embodiment of the present invention. FIG. 1 C shows an intermediate stage, wherein inner elongated element 22 is partially distally extended. In some embodiments, the distal extension of inner elongated element 22 will be stopped at this point by stopping mechanism 33 or by manually holding inner elongated element 22 in place. In other embodiments, inner elongated element 22 will be extended distally until extended further, as in FIG. 1A.

[0031] In accordance with the features of the present invention, it will be appreciated that an embodiment that includes a treatment or diagnostic agent disposed on balloon outer surface 31 eliminates the disadvantages of other drug coated balloon systems. In the present invention, the drug is maintained inside the catheter during advancement to the target location in the vessel, protecting against the drug loss during transit that is common in other designs, or drug loss that occurs from retracting an outer sheath. The balloon everts forward in a distal direction, following the contour of the vessel, and treatment length and diameter can be controlled and adjusted to precisely match the intended target. Advancement of catheter body 12 to a target location may be assisted by use of guidewires as known in the art. The inner elongated element 22 may include an inner elongated element lumen 23, and further include a guidewire 39 therethrough, as shown in FIGS. 4A- 4C. In other embodiments, catheter unit 10 may include a distal rail element 34 at the distal end of either the outer elongated element 20 or inner elongated element 22 (as shown in FIG. 2, for example), wherein the distal rail element 34 is slidable over a guidewire.

[0032] Reference is now made to FIG. 2, which is an illustration of catheter unit 10 including a distal rail element 34 in accordance with embodiments of the present invention. Distal rail element 34, having a distal rail element lumen 35, is attached by suitable means to inner elongated element distal end 18. Distal rail element 34 is adapted to slide over a guidewire wherein in one embodiment, the guidewire, when positioned within distal rail element 34, will traverse alongside outer elongated element 20. [0033] Reference is now made to FIG. 3, which is an illustration of catheter unit 10 in accordance with yet an additional embodiment of the present invention. In the embodiment shown in FIG. 3, inner elongated element 22 has an inner elongated element lumen 23 extending from inner elongated element proximal end 16 to inner elongated element distal end 18. Balloon distal end 30 is bonded or otherwise attached to the inner elongated element distal end 18. In a pre-deployment configuration, wherein balloon 28 is positioned within outer elongated element lumen 21 with balloon inner surface 1 1 adjacent to outer elongated element inner surface 19, and balloon distal end 30 positioned proximal to balloon proximal end 29, the system further includes an introducing element 37 within inner elongated element lumen 23. Introducing element 37 extends proximally from outer elongated element distal end 27 to and beyond inner elongated element proximal end 16. Introducing element 37 includes an introducing lumen 38 adapted to accommodate a moveable guidewire therethrough. Catheter unit 10 may be advanced over the moveable guidewire to the treatment zone, and prior to deployment of balloon 28, introducing element 37 is removed from the inner elongated element lumen 23. A moveable guidewire placed through introducing lumen 38 may remain in place in the vessel after introducing element 37 is removed from the vessel. This may be done for various reasons, including the possibility of having to cross the lesion again or having to introduce a stent or an additional catheter, for example.

[0034] Reference is now made to FIGS. 4A-4C, which are schematic illustrations of catheter unit 10 and methods of use thereof in accordance with embodiments of the present invention. As shown in FIGS. 4A-4C, catheter unit 10 in one embodiment is designed to occlude a blood vessel 41 at a location proximal to a treatment zone, and eversion of the balloon will progress with the balloon unrolling while maintaining contact with the wall of the blood vessel 41 . In accordance with embodiments of the present invention, inner elongated element 22 may have an inner elongated element lumen 23 extending from inner elongated element proximal end 16 to inner elongated element distal end 18. Balloon distal end 30 is bonded or otherwise attached to inner elongated element 22 at an attachment point 40 that is proximal to inner elongated element distal end 18. The catheter and method shown in FIGS. 4A-4C allow for passage through a tight-fitting lesion 42. In a pre-deployment configuration, as shown in FIG. 4A, balloon 28 is positioned within the outer elongated element lumen 21 with balloon inner surface 1 1 adjacent to outer elongated element inner surface 19, and balloon distal end 30 is positioned proximal to balloon proximal end 29. Eversion of balloon 28 from outer elongated element lumen 21 will initially occlude the blood vessel 41 at a location proximal to the treatment zone, and will concurrently begin advancement of inner elongated element 22 distally into the vessel 41 . As shown in FIG. 4B, balloon 28 begins to dilate lesion 42 that has narrowed the blood vessel 41 to facilitate advancement of inner elongated element 22. In this embodiment, balloon 28 is made from a material that can withstand inflation pressures high enough to effect dilatation of the lesion; such materials are known in the art, and may include semi-compliant or non- compliant polymers such as nylon, polyamides, polyimides, polyolefins, PET and others. Continued eversion of balloon 28 will advance the inner elongated element 22 through lesion 42, as shown in FIG. 4C. Since balloon distal end 30 is attached to inner elongated element 22 at a point which is proximal to inner elongated element distal end 18, in this embodiment inner elongated element 22 will extend distally into the vessel past balloon 28, allowing for additional treatment options. For example, inner elongated element 22 may be used for insertion of a guidewire past the lesion. Alternatively, inner elongated element 22 may be used to provide additional force for crossing of tight lesions. In some embodiments, inner elongated element 22 may eliminate the need for an introducing element, which can allow for a potentially smaller profile catheter unit 10. Other potential advantages may be envisioned as well. A guidewire 39 may optionally be placed into the inner elongated element lumen 23, and exit from guidewire exit port 24. In applications where there is no narrowing of the vessel, balloon 28 may be comprised of a very compliant material to minimize potential trauma to the vessel that may be caused by dilatation. Such materials are known in the art, and may include polyurethanes, latex, silicones and others.

[0035] Reference is now made to FIG. 5 which is an illustration of a system 8 having a catheter unit 10 in accordance with another embodiment of the present invention. System 8 may further include a control unit 72, which will be described further hereinbelow. Catheter unit 10 is similar in construction to catheter unit 10 shown in FIGS. 1 A-1 C, with an additional feature of a supply element 43 positioned external and coaxial to inner and outer elongated elements 22 and 20. Supply element 43 is configured for removing blood from the blood vessel during treatment.

[0036] In one embodiment, supply element 43 has inlet ports at one or more locations along its length for receiving blood from the blood vessel. In a preferred embodiment, as shown in FIG. 5, supply element 43 has an inlet port 44 located at a supply element distal end 45. In this embodiment, inlet port 44 is created by the coaxial arrangement of supply element 43 and outer elongated element 20, wherein an inner diameter of supply element 43 is sized at least 0.1 mm greater than an outer diameter of outer elongated element 20. The space created by this difference in diameter creates a port which is sufficiently sized for receiving blood from the vessel, as will be described in greater detail hereinbelow.

[0037] A supply hub 46 may connect supply element 43 and inner elongated element 22 to control unit 72. Control unit 72 may thermally alter (i.e. heat or cool) blood received from supply element 43 (represented by solid arrows 76), and send the altered blood (represented by dashed arrows 78) into the blood vessel through inner elongated element 22. Blood received from supply element 43 may be treated or altered in other ways as well (e.g., oxygenate, thin, drug modified, etc.), or may be used to perfuse the vessel distal to inner elongated element distal end 18.

[0038] In one embodiment, supply element 43 is a standard vascular sheath and supply hub 46 may be a side arm from which blood is removed from the vessel and in some embodiments sent to control unit 72. In another embodiment, supply element 43 is an extended sheath, and may extend distally to 100 cm or more depending on the application.

[0039] Referring again to FIG. 3, in embodiments of the present invention, radiopaque markers 47 may be included on inner elongated element distal end 18 and outer elongated element distal end 27, for visualization of the position of catheter body 12 within the vessel and relative positions of inner and outer elongated elements 22 and 20. Radiopaque markers 47 may, for example, be a ring surrounding the respective positions on inner and outer elongated elements 22 and 20 or, in order to minimize stiffness, a radiopaque marker may be comprised of a small sliver of radiopaque material embedded within a portion of the inner elongated element 22 and outer elongated element 20. Alternatively, portions of inner elongated element 22 and outer elongated element 20 may be comprised of radiopaque material. It should be readily apparent that any of the embodiments described above may further include radiopaque markers thereon.

[0040] In some embodiments, inner elongated element lumen 23 may be maintained and used for other items even when not in use for movable guidewire 39. For example, a mandrel may be introduced through inner elongated element lumen 23 for enhancing pushability and for advancing catheter body 12 or inner elongated element 22. In some embodiments, inner elongated element lumen 23 may be used for exchanging guidewires, or for putting a second guidewire in the vessel. Alternatively, inner elongated element lumen 23 may be used for perfusion. For example, in a case of prolonged occlusion while treating the vessel , blood may be introduced through inner elongated element lumen 23 to an area distal to balloon 28, thus making it possible to keep treating the vessel for as long as necessary. This may be particularly useful in the coronary arteries, for example, which cannot be occluded for a prolonged period of time. In some embodiments, blood may be cooled, oxygenated or otherwise treated, and then introduced through inner elongated element lumen 23. In some embodiments, a supply elongated element is included as well, as described with reference to FIG. 5, for removing blood from the vessel which may then be reintroduced through inner elongated element lumen 23.

[0041] As discussed above, depending on the intended application of catheter unit 10, balloon 28 may be elastomeric, compliant, semi-compliant or non-compliant. In one embodiment, the balloon is pre-formed and relatively thin, so as to reduce the pressure necessary to inflate the balloon, while keeping the outer diameter to a minimum. For example, balloon thickness may range from 0.0001 inches to 0.002 inches. Balloon 28 may be formed integral with either inner elongated element 22 or outer elongated element 20. Alternatively, balloon 28 may be attached to inner and outer elongated elements by adhesive, mechanical, heat bonding or other means known in the art. [0042] Reference is now made again to FIGS. 4A-4C. In accordance with another embodiment of the present invention, a method is provided to cross a tight lesion. In this embodiment, inner elongated element 22 has an inner elongated element lumen 23 extending from inner elongated element proximal end 16 to inner elongated element distal end 18. Balloon distal end 30 is bonded or otherwise attached to inner elongated element 22 at a location 40 that is proximal to inner elongated element distal end 18. Inflation fluid is introduced through hub 32 into outer elongated element lumen 21 . Introduction of inflation fluid causes eversion of balloon 28 from the outer elongated element lumen 21 as described above, and additionally causes advancement of the inner elongated element 22 distally into and through lesion 42. Alternatively or in addition, inner elongated element 22 may be advanced manually through lesion 42. Once the inner elongated element 22 is positioned through lesion 42, balloon 28 may be fully expanded, as shown in FIG. 4C. A guidewire 39 may optionally be placed into the inner elongated element lumen 23, and exit from guidewire exit port 24.

[0043] Reference is now made to FIGS. 6A-6C, which are schematic illustrations showing catheter unit 10 and methods of use thereof, in accordance with additional embodiments of the present invention.

[0044] A vessel 41 is shown with a lesion 42. As shown in FIG. 6A, catheter 10, in a pre-deployment configuration, is introduced into vessel 41 and is positioned adjacent lesion 42. While catheter 10 is in position adjacent lesion 42, inflation fluid is introduced through hub 32 into outer elongated element lumen 21 . Introduction of inflation fluid into the outer elongated element lumen 21 causes balloon 28 to begin to unroll and evert distally from outer elongated element lumen 21 into vessel 41 , proximal to lesion 42, occluding vessel 41 . As shown in FIG. 6B, with continued introduction of inflation fluid, eversion of the balloon will progress with the balloon unrolling while maintaining contact with the wall of the blood vessel, partially dilating lesion 42 (FIG. 6B), and unrolling through lesion 42. Eversion of the balloon may be halted at a desired point to provide a preferred length of the balloon using stopping mechanism 33 or alternatively, by holding inner elongated element 22 stationary with respect to outer elongated element 20. With the eversion halted at the desired location, inflation fluid continues to be introduced into outer elongated element lumen 21 . This continued introduction of inflation fluid into the outer elongated element lumen 21 will cause balloon 28 to expand radially to a desired diameter, as depicted in FIG. 6C. In some embodiments, a diagnostic or therapeutic agent resides on the outer surface of balloon 28, and the expanded balloon causes occlusion of blood flow to the vessel and precise contact of the outer surface of balloon 28 with lesion 42, thus providing efficient delivery of agent to the lesion 42.

[0045] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0046] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

CLAIMS What is claimed is:

1 . A catheter unit comprising: an inner elongated element having an inner elongated element proximal end and an inner elongated element distal end; an outer elongated element, having an outer elongated element proximal end, an outer elongated element distal end, and an outer elongated element lumen extending from said outer elongated element proximal end to said outer elongated element distal end, said outer elongated element positioned external to and coaxially with respect to said inner elongated element, wherein said inner elongated element is movable with respect to said outer elongated element; and a balloon having a balloon proximal end and a balloon distal end, said balloon attached to said inner and outer elongated elements, wherein said balloon proximal end is attached to said outer elongated element distal end and said balloon distal end is attached to said inner elongated element wherein in a pre-deployment configuration the balloon is positioned within said outer elongated element lumen, with a balloon inner surface adjacent to an inner surface of said outer elongated element.

2. The catheter unit of claim 1 , wherein said inner elongated element comprises an inner elongated element lumen.

3. The catheter unit of claim 1 , further comprising a treatment or diagnostic agent disposed on an outer surface of the balloon.

4. The catheter unit of claim 2, further comprising a guidewire positioned within said inner elongated element lumen.

5. The catheter unit of claim 1 , further comprising a distal rail element at the distal end of either the outer elongated element or inner elongated element, wherein the distal rail element is slidable over a guidewire.

6. The catheter unit of claim 1 wherein upon introduction of inflation fluid into said outer elongated element lumen, said balloon is configured to unroll and evert distally from the outer elongated element lumen into a desired treatment zone of a blood vessel.

7. The catheter unit of claim 6, wherein advancement of said inner elongated element is configured to assist the unrolling and eversion of the balloon.

8. The catheter unit of claim 6, further comprising a stopping mechanism to stop the eversion at a desired point to provide a preferred length of the balloon.

9. The catheter unit of claim 8, wherein when said eversion of the balloon is stopped at the preferred length, continued introduction of inflation fluid into the outer elongated element lumen will cause the balloon to expand radially to a desired diameter.

10. The catheter unit of claim 1 , further comprising a hub at said outer elongated element proximal end, said hub configured for introducing a delivery substance into said outer elongated element lumen.

1 1 . The catheter unit of claim 1 , wherein the distal end of the balloon is bonded or otherwise attached to the distal end of the inner elongated element.

12. The catheter unit of claim 1 , wherein the distal end of the balloon is bonded or otherwise attached to the inner elongated element at a location proximal to the distal end of the inner elongated element.

13. The catheter unit of claim 12, wherein eversion of the balloon from the outer elongated element will advance the inner elongated element distally into the vessel.

14. The catheter unit of claim 1 , further comprising a supply element coaxial to the outer elongated element, said supply element having an inlet port at a distal end thereof, wherein the inlet port is proximal to the outer elongated element distal end.

15. A method for treating a vessel, the method comprising: introducing into a vessel, a catheter unit having an inner elongated element and an outer elongated element positioned coaxially with respect to the inner elongated element, and a balloon attached to the inner and outer elongated elements, wherein a balloon proximal end is attached to an outer elongated element distal end, a balloon distal end is attached to the inner elongated element, and wherein in a pre-deployment configuration, the balloon is positioned within an outer elongated element lumen, with a balloon inner surface adjacent to an outer elongated element inner surface, and wherein in the pre-deployment configuration, said balloon distal end is positioned proximal to said balloon; introducing an inflation fluid into the outer elongated element lumen; and unrolling the balloon via the introducing of the inflation fluid, wherein during said unrolling, the balloon is everted distally past the outer elongated element lumen and into a desired treatment zone of the vessel.

16. The method of claim 15, wherein said unrolling comprises only partially everting the balloon so as to obtain a particular length of balloon within the vessel .

17. The method of claim 15, further comprising delivery of a therapeutic or diagnostic agent on an outer surface of the balloon.

18. The method of claim 15, further comprising advancement and placement of said inner elongated element lumen within a lesion.

19. The method of claim 15, further comprising expanding the diameter of the balloon after the unrolling of the balloon to dilate a narrowed or occluded segment.

20. The method of claim 15, wherein said inner elongated element comprises an inner elongated element lumen, the method further comprising perfusing blood through said inner elongated element lumen and into the vessel.

21 . The method of claim 15, further comprising removing blood via a supply elongated element, said supply elongated element positioned coaxial to said outer elongated element.