Rivet shunt and method of deployment

Abstract

To provide a shunt that effectively and safely treats multiple conditions while at the same time allows ease of use and reduced costs.SOLUTION: As a shunt 100 is deployed, its length substantially decreases to 101' and its diameter increases. End portions 100A increase to a maximum radial diameter 103' and then decrease in diameter towards a middle region 100B, which has a diameter 103". Thereby, the flared end portions engage the tissue surrounding a puncture or aperture within a patient's tissue. The shunt is fixed to the puncture or aperture.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] (Related Applications) This application claims priority to U.S. Provisional Application No. 62 / 802,656, entitled "Method and Technology for Creating Connections and Shunts Between Vessels and Chambers of Biological Structures", filed on February 7, 2019; U.S. Provisional Application No. 62 / 896,144, entitled "Rivet Stent", filed on September 5, 2019; and U.S. Provisional Application No. 62 / 942,631, entitled "Resizable Rivet Stent", filed on December 2, 2019, all of which are hereby incorporated by reference in their entirety.

Background Art

[0002] An artificial shunt functions as a hole or small passage that allows the movement of fluid from one part of a patient's body to another, or more specifically, from one body lumen to another. Such body lumens can be associated with virtually any organ in the body, but are most commonly associated with lumens in the heart, lungs, skull, and liver.

[0003] Shunts can be used to treat many different conditions. Such conditions include, but are not limited to, pulmonary hypertension, heart failure, hypertension, renal failure, volume overload, hypertrophic cardiomyopathy, valve regurgitation, and numerous congenital diseases.

[0004] As exemplified in U.S. Patent No. 9,551,083, a number of prior art shunt designs exist, the content of which is incorporated herein by reference. As will be understood by those skilled in the art, the effectiveness and safety of a shunt in its intended use depends primarily on attributes such as accurate shunt placement, secure shunt fixation, shunt durability, minimization of possible fluid stagnation regions, ease of placement, and adaptability over time, to name a few.

[0005] Therefore, it is necessary to constantly improve and refine prior art shunt designs to arrive at a shunt that can effectively and safely treat multiple conditions while at the same time enabling ease of use and cost reduction. SUMMARY OF THE INVENTION

[0006] In one embodiment, the present invention relates to a shunt that expands into an hourglass shape. As the shunt expands, its both ends spread radially outward with respect to its middle portion. Further, the length of the shunt becomes shorter, whereby the expanded ends engage with the tissue surrounding the puncture or opening in the patient's tissue, which is not entirely unlike a rivet. In an alternative embodiment, only one of its both ends expands radially outward with respect to its middle portion, while the other end maintains a diameter similar to that of its middle portion.

[0007] In one embodiment, the shunt achieves this shape by having a laser-cut body that forms a plurality of cells. The cells near the middle of the shunt have a smaller size (e.g., length, width) than the remaining cells. The cells near both the proximal and distal ends of the shunt have a larger size (e.g., length, width) than the middle cells and expand radially to a larger diameter. Further, as the cells expand radially, the width of the cells increases, and as a result, the length of the cells decreases. As the length of the cells decreases, the shunt as a whole shortens or decreases in length.

[0008] In one embodiment, the shunt can be placed using a balloon catheter. The shunt is compressed on the outer peripheral surface of the balloon catheter and, when inflated, expands the shunt.

[0009] In one embodiment, the balloon catheter has a balloon that expands into an hourglass shape. In other words, the proximal and distal regions of the balloon expand to a larger diameter relative to its middle portion.

[0010] In an example of the method of the present invention, the distal end of the balloon catheter has a shunt disposed on the outer peripheral surface of the balloon. The shunt and the balloon are disposed substantially in the middle through an opening in the patient's tissue. As the balloon expands into an hourglass shape, the shunt expands into an hourglass shape as well and at the same time shortens. Thereby, the expanded ends of the shunt engage the tissue surrounding the opening.

[0011] The conventional method further includes a subsequent secondary expansion of the shunt, which can further increase its diameter. This can be achieved by advancing a second balloon catheter into the shunt and expanding its balloon to the desired shunt passage diameter.

[0012] In another embodiment of the present invention, the shunt comprises barbs, hooks or similar fixation mechanisms on its outer surface.

[0013] In another embodiment of the present invention, the shunt may comprise a cover portion disposed along its entire length or only along a part of its length (e.g., the middle part).

[0014] In another embodiment, the balloon supply catheter may comprise a positioning device that provides a tactile resistance indicating that the shunt is aligned at the desired position. For example, the positioning device may comprise a plurality of arm portions extending from the catheter body, an annular ring portion disposed on the outer surface of the shunt, or a shunt portion heat-set to expand radially.

Brief Description of the Drawings

[0015] The above and other aspects, features, and advantages of the embodiments of the present invention will become apparent and be elucidated from the following description of the embodiments of the present invention with reference to the accompanying drawings.

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Mode for Carrying Out the Invention

[0040] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. The terms used in the detailed description of the embodiments shown in the accompanying drawings are not intended to limit the present invention. In the drawings, like numbers refer to like elements.

[0041] The present invention generally relates to a shunt and a method of placing a shunt. More specifically, the shunt radially expands into an hourglass shape or a rivet shape while also shortening longitudinally. The shunt is first placed within an opening in the tissue and then expanded, whereby the distal and proximal ends of the shunt expand radially outward and move towards each other. When fully expanded, these radially expanded ends engage the tissue surrounding the opening, creating a smooth transition between both sides of the tissue.

[0042] This shunt design offers several advantages over conventional shunt designs. For example, due to its expanded shape, the shunt can "self-position" itself within the opening of the tissue, thus improving its positioning accuracy compared to conventional designs. Also, the expanded portion provides a strong connection to the surrounding tissue compared to conventional shunt designs. Finally, the shunt may have a small collapsed profile and still be able to expand to a consistent inner diameter with high radial force. This allows the use of a low-profile balloon to assist in the expansion of the shunt and achieve consistent and reliable implantation results.

[0043] A stent design that can be modified for use as a shunt in accordance with the principles of the invention as described herein is disclosed in Oepen U.S. Patent No. 6,068,656, the entire contents of which are incorporated herein by reference.

[0044] As discussed in more detail herein, the shortened and hourglass shape can be achieved in several different ways and the shunt itself can have several different features. It should be clearly understood that the features shown in different embodiments herein can be used interchangeably with the features of other embodiments herein. In other words, the features of the embodiments are intended to be "mixed and matched" with each other.

[0045] Figures 1A and 1B show the shape changes of one embodiment of the tubular shunt 100 of the present invention. In Figure 1A, the shunt 100 is shown in a radially compressed configuration having a relatively long length 101 and a relatively small uniform diameter 103. When the shunt 100 is placed, its length decreases substantially to 101' and its diameter increases. More specifically, the end 100A increases radially to a maximum diameter 103' and then decreases in diameter towards the intermediate region 100B having a diameter 103".

[0046] In one example, when compressed, the shunt 100 has a length 101 of about 20 mm and a diameter 103 of about 1.5 mm, and when expanded, the shunt 100 has a diameter 103' of the end portion 100A of about 8 mm and a diameter 103'' of the intermediate region 100B of about 5 mm.

[0047] In another example, when compressed, the shunt 100 has a length 101 of about 30 mm and a diameter 103 of about 2.2 mm, and when expanded, the shunt 100 has a diameter 103' of the end portion 100A of about 8 mm and a diameter 103'' of the intermediate region 100B of about 4 mm.

[0048] In another example, when compressed, the shunt 100 has a length 101 of about 22 mm and a diameter 103 of about 3.5 mm, and when expanded, the shunt 100 has a diameter 103' of the end portion 100A of about 24 mm and a diameter 103'' of the intermediate region 100B of about 20 mm.

[0049] As shown in FIGS. 2-4, the present embodiment of the shunt 100 includes a plurality of tubular radial bands 107, each formed from a plurality of uniform and alternately waved ones that generate a shunt passage 100C. Taking another approach, particularly referring to FIGS. 3 and 4A, each radial band 107 includes a plurality of straight regions 107B joined together, creating a pattern of triangular peaks 107A with alternating longitudinal directions. The peaks 107A of each radial band 107 are aligned with each other and connected via small straight portions 109, and when compressed radially, they effectively create rhombus-shaped cells 102. As a result of this design, the angle of each peak 107A increases as the shunt 100 expands radially and the radial bands 107 approach each other, which results in a shortening in the longitudinal direction (i.e., a decrease in the length of the shunt 100).

[0050] One mechanism that causes a radial expansion of the end 100A of the shunt 100 is shown in FIGS. 4A and 4B. These figures show a pattern as if the shunt 100 were longitudinally cut and flattened. Specifically, a pattern of cells 102 is created in which the length from the proximal end to the distal end of some cells 102A, 102B, 102C, 102D is longer than that of other cells (i.e., has a longer straight region 107B). Preferably, the intermediate cells 102 of the shunt 100 have the minimum length, and as the distance from the middle increases, the length of each row of cells 102 gradually increases. Alternatively, the longer cells 102 may be arranged only near the ends of the shunt 100.

[0051] For example, the intermediate cell 102A has a first length, the longitudinally adjacent cell 102B has a second length longer than that of the cell 102A, the longitudinally adjacent cell 102C has a third length longer than that of the cell 102B, and the longitudinally adjacent cell 102D has a fourth length longer than that of the cell 102C.

[0052] To better understand this difference, in FIG. 4B, cells 102A and 102D are juxtaposed and compared. In the compressed configuration, the larger cell 102D has a longer straight portion 107B and a smaller angle of peak 107A with respect to the cell 102A. However, when expanding, the larger straight portion 107B allows these cells to contract more than the cell 102A and expand to a larger diameter. In this way, the expansion shape and the amount of shortening can be determined.

[0053] The sizes and ratios of the cells 102 and the straight portions 107B can be varied according to the desired expanded shape of the shunt 100. For example, by having dramatically large end cells (e.g., cells 102C and 102D), the expanded configuration of the shunt 100 may have a larger expanded diameter size relative to its middle portion. In one particular example, the increase in the size of the straight portion 107B (i.e., struts) of each radial band 107 can be seen in the following list. This starts from the straight portion 107B of the middle cell 102A and proceeds towards the ends of the shunt 100. In the case of a shunt having enlarged portions at both ends, the progression of the size increase is the same on both sides of the central region of the shunt. With the inventive configuration of the size progression described herein, one enlarged portion can be of a different size or different configuration than the enlarged portion on the opposite side, and thus it will be understood that the shunt is particularly adjustable for a particular use and location within the patient's body. Note that this particular example shows a greater number of straight portions 107B, and thus cells 102, than that shown in FIG. 4A. However, the shunt 100 can include a variety of different quantities of cells. Exemplary sizes of the straight portion 107B are 1.218 mm, 1.242 mm, 1.287 mm, 1.351 mm, 1.432 mm, 1.528 mm, 1.638 mm, 1.763 mm, 1.897 mm, 2.036 mm.

[0054] In addition to the variable size of the cells 102 along the length of the shunt 100, the shunt 100 can be heat set into an hourglass shape when unrestricted to provide additional expansion force, with or without the assistance of a balloon catheter.

[0055] Notwithstanding the cell design described above, it should be noted that according to the present invention, deformation of multiple cells is contemplated. In this regard, an important design parameter is that each "row" or band in the shunt body reaches maximum expansion at a particular diameter to achieve the final desired shape.

[0056] As shown in FIGS. 5 and 6, the shunt 100 is supplied via the balloon catheter 110 and can be expanded. In one embodiment, the balloon 114 is disposed at the distal end of the tubular catheter body 112. The interior of the catheter body 112 has an inflation lumen 112A that communicates with the proximal inflation port and the distal inflation port 112B within the balloon 114. The guide wire lumen 116 is disposed within the catheter body 112 and communicates with the proximal and distal ends of the body 112.

[0057] As shown in FIG. 6, the balloon 114 can expand into an hourglass shape having an intermediate region 114C with a diameter smaller than the proximal region 114A and the distal region 114B of the balloon 114. There are several different techniques for achieving this inflated shape of the balloon 114. For example, the balloon 114 can be constructed from a compliant material and a non-compliant band (not shown) can be disposed around the intermediate region 114C. In another example, the proximal region 114A and the distal region 114B can be constructed from a material having different expansion characteristics than the intermediate region 114C (e.g., a compliant intermediate region with non-compliant proximal / distal regions, or a non-compliant intermediate region with compliant proximal / distal regions).

[0058] FIGS. 7 and 8 show the shunt 100 disposed on the outer peripheral surface of the balloon 114. Preferably, the shunt 100 is provided on the balloon 114 such that the intermediate region 100B of the shunt 100 is aligned with the intermediate region 114C of the balloon 114. When the balloon 114 expands, the proximal region 114A and the distal region 114B expand the end regions 100A of the shunt 100 to a diameter larger than the intermediate region 100B.

[0059] Figures 9 and 10 illustrate how the shunt 100 can be delivered to the area of the target tissue 10. First, an initial aperture is made at the desired location (e.g., using a needle). Next, the distal end of the delivery catheter 110 is advanced through the aperture in the tissue 10 such that substantially equal portions of the shunt 100 are present on either side of the tissue 10. Either the shunt 100 or the delivery catheter 110 can be provided with radiopaque markers at various known locations to assist the physician in achieving the desired alignment.

[0060] Once the desired alignment is achieved, the balloon 114 is inflated and the shunt 100 radially expands and shortens into an hourglass shape. The shunt 100 is configured such that upon shortening, the expanded end regions 100A engage and are pushed into the tissue 10. These expanded end regions 100A as well as the proximal region 114A and distal region 114B of the balloon serve to "self-center" the shunt 100 in the appropriate position. The end result is an opening in the tissue 10 having smooth funnel-shaped transitions on each side of the tissue.

[0061] One variation of this delivery technique allows for the passage through the shunt 100 (i.e., the narrowed intermediate region 110B) to be sized after delivery if necessary. Specifically, the shunt 100 can be delivered as described above, but the narrowed intermediate region 110B is expanded to an initial diameter that is smaller than the intermediate region 110B is expandable. This can be achieved, for example, by restricting the expansion size of the intermediate region 114C of the balloon 114. If the physician determines that it is beneficial to increase the size of the intermediate region 100B of the shunt 100, the diameter of the intermediate region 100B can be further expanded by different portions of the balloon (e.g., 114A or 114B) or by a second balloon catheter that expands to the desired passage diameter.

[0062] Alternatively, if the physician determines that the intermediate region 100B of the shunt 100 was initially placed with a diameter larger than desired, a tubular spacer having a thickness that reduces the size of the passage through the intermediate region 100B may be supplied using a second supply catheter. In one example, the tubular spacer may be similar to the initially placed shunt, but may be a second shunt 100 disposed inside the first shunt.

[0063] This ability to resize the shunt 100 after supply enables the physician to customize the amount of fluid shunted for an individual patient. Also, if the patient's hemodynamics require a change, the shunt 100 can be revised at a later date.

[0064] In an alternative embodiment, the balloon catheter may comprise two or three separate, independently inflatable balloons that can be inflated to different sizes to achieve a similar hourglass shape. This allows the physician to ensure that the ends of the shunt 100 expand radially enough to engage the surrounding tissue while restricting the expansion of the intermediate portion of the shunt 100 to a desired diameter.

[0065] In another alternative embodiment, instead of using a balloon, a mechanical device on the catheter can be used to expand the shunt 100. For example, such a catheter may comprise two conical structures that are slidable longitudinally towards each other. The shunt 100 may be disposed between these two structures such that they expand the shunt 100 as they move towards each other.

[0066] As discussed above, the shunt 100' may be composed of a shape memory material and is heat set to an hourglass shape that expands when unrestricted. In such an embodiment, the balloon catheter 110 may not be necessary. FIGS. 11 and 12 show a similar delivery procedure using a delivery catheter 120 configured for placement of the heat set shunt 100. The catheter 120 includes an elongate catheter body 122 having a storable sheath 124 disposed around the shunt 100'. Similar to the placement procedure described above, the distal end of the catheter 120 is positioned through the opening in the tissue 10 such that substantially equal portions of the shunt 100 are disposed on each side of the tissue 10. When the desired alignment is achieved (e.g., by reference to radiopaque markers at known locations), the sheath 124 is retracted proximally and the shunt 100' radially expands and shortens into the hourglass shape as shown in FIG. 12.

[0067] In one embodiment, the shunt 100 may include a plurality of return portions 113, hook portions, or similar fixation structures as seen in FIG. 13. These may be disposed outside the expanded region so as to penetrate the patient's tissue when the shunt 100 expands. Alternatively, the return portions 113 or similar fixation structures may be disposed at various positions along the length of the shunt 100 so as to point radially outward.

[0068] In one embodiment, the shunt 100 acts to maintain an opening through the tissue by mechanical force without any kind of cover. FIG. 14 shows another embodiment of a shunt 130 having a similar laser cut structure 132 as the shunt 100 but also having a cover layer 134 attached to the laser cut structure 132 (either outside or inside the structure 132) that forms a similar tubular and hourglass shape. To accommodate the change from tubular to hourglass shape, some or all of the material of the cover layer 134 may be elastic or stretchable. Alternatively, the tubular cover layer 134 may be included only in the intermediate region of the laser cut structure 138 of the shunt 136 as shown in FIG. 15.

[0069] In another embodiment, any of the shunts may have two laser cut structural layers disposed on the inner and outer surfaces of the cover layer so as to "sandwich" the cover layer.

[0070] It may be desirable to occlude an existing shunt (e.g., a naturally occurring tissue passageway) or a chamber such as the left atrial appendage. In this regard, any of the shunt embodiments herein may extend across the central lumen of the shunt and include a material for occlusion. For example, the material may be a polymeric sheet attached to the end of the device having a small hole in the center. The polymeric sheet may be elastic such that the entry hole expands with the balloon from the delivery catheter and then returns to effectively seal the opening when the balloon is removed.

[0071] Shunt 100 and its variations have been described above as expanding to an enlarged hourglass shape, but other variations of the expanded shape are possible. For example, FIG. 22 shows a shunt 180 in which only one end is radially expanded outward while the opposite end 180C maintains a diameter similar to that of the intermediate region 180B. Since the length of the shunt 180 is shortened, it may be beneficial to have a return portion or other securing mechanism along the intermediate region 180B and the end 180C to assist in securing the shunt 180 during radial expansion.

[0072] In another example, neither end of the shunt expands to a flared shape.

[0073] The shunts described herein can be composed of biocompatible materials such as Nitinol or similar alloys, or bioabsorbable materials such as magnesium, PLA, or PLA-PGA. Additionally, the shunts described herein may have a polymer coating known to promote tissue growth, or features that promote endothelization such as open surface pores with a diameter of approximately 60 microns.

[0074] Although shunt 100 has been described in a particular pattern, it should be understood that other patterns and designs are possible to achieve a similar function. For example, FIGS. 16A and 16B show a shunt 140 comprising a plurality of rings 144 including a plurality of alternating peaks. These rings 144 are fixed to a cover 142 and may not be connected to each other (other than the cover) or may have a connecting member 148 connecting adjacent peaks in the longitudinal direction. The ends of shunt 140 each comprise an end ring 146 composed of a plurality of alternating peaks larger than the peaks of rings 144. As shown in FIG. 16B, when expanded radially, the peaks of rings 144 compress longitudinally against each other and conform to each other.

[0075] With respect to FIG. 16B, in one embodiment, the illustrated shape is achieved by over-expanding the shunt with a balloon. This causes the ends to expand and open as shown, and the expansion of the central section is restricted by cover 142.

[0076] In addition to having different laser cut patterns, alternative embodiments may instead be composed of a plurality of braided wires such as shunt 180 shown in FIGS. 17 and 18. Shunt 180 can be braided onto an hourglass-shaped mandrel using a plurality of shape memory wires. After braiding, shunt 180 is heat set on the mandrel and then removed. This allows it to be compressed into a tubular shape and radially expanded into an hourglass shape (i.e., an expanded end region 180A and a smaller diameter intermediate region 180B).

[0077] As discussed above, the supply catheters 110 and 120 can include radiopaque markers to assist the physician in aligning the shunt 100. However, other positioning devices can also be used to assist in positioning.

[0078] For example, FIG. 19 shows a supply device 150 that includes an elongated arm 152 connected to the catheter body at the proximal end and configured to radially expand away from the shunt 100 at the distal end 154. The arm 152 is preferably of a length such that when the shunt 100 is disposed in a desired alignment position (e.g., approximately midway through the opening), the rounded distal tip contacts the tissue 10. This contact by the arm 152 provides tactile feedback to the user in addition to visualization of the radiopaque marker. To prevent damage to the tissue 10, the arm 152 is preferably constructed of a flexible material such as nitinol, stainless steel, Pebax, nylon, polyurethane, or other plastic. The arm 152 can be relatively straight or can form a plurality of waves to provide additional flexibility and compressibility.

[0079] FIG. 20 shows another embodiment of a supply device 160 that includes an annular ring 162 disposed on the outer peripheral surface of the shunt 100 to assist in aligning the shunt 100 in a desired position. The annular ring 162 preferably has a thickness such that it is larger than the opening in the tissue 10 when the shunt 100 is compressed. The ring 162 is longitudinally disposed on the proximal end side of the shunt 100 such that when the ring 162 contacts the tissue 10, the shunt 100 achieves a desired longitudinal alignment through the tissue opening. The ring 162 can be constructed of cloth, polymer, or a bioabsorbable material.

[0080] Alternatively, instead of the annular ring 162, the shunt 100 itself may comprise a structure 172 on the shunt 100 that is heat set to expand radially, as seen in the device 170 of FIG. 21. For example, the structure may be a loop, flap, or similar structure that pops out radially when a loop, flap, or overlapping sheath is pulled out from the shunt. Similar to the ring 162, these structures 172 are positioned in such a location as to provide tactile feedback to the physician to indicate the desired alignment of the shunt 100 within the tissue opening.

[0081] This specification has focused on various embodiments of shunts used to create a shunt within a patient's body or to close a hole between two blood vessels or heart chambers, but other uses are possible. For example, the shunt 100 may be used as an anchor and / or attachment point for additional structures (e.g., tubes, other shunts, etc.). In another example, the shunt 100 may be used as a fixation point for an artificial valve such as a mitral valve or an aortic valve. In another example, the shunt 100 may be used to help restore a circular shape to a structure (e.g., coarctation of the aorta).

[0082] The shunts and delivery methods described herein can be used for a wide variety of shunt procedures. One example is a right-to-right shunt between the right pulmonary artery and the superior vena cava, between the pulmonary artery and the right atrium, between the pulmonary artery or right ventricle and the venous system, or between the azygos vein and the inferior vena cava. These techniques can be seen in more detail in Application No. 16 / 576,704, entitled "Methods And Technology For Creating Connections And Shunts Between Vessels And Chambers Of Biologic Structures", filed on September 19, 2019 (incorporated herein by reference). Other possible uses include atrial septostomy, creation of an arteriovenous shunt for the treatment of hypertension, creation of an arteriovenous shunt for fistula creation for dialysis patients, creation of a shunt between cardiac chambers such as from the left atrium to the coronary sinus, from the pulmonary artery to the aorta, or from the aorta to the pulmonary artery.

[0083] While the invention has been described with respect to specific embodiments and uses, those skilled in the art will be able to generate additional embodiments and modifications in light of this teaching without departing from the spirit of the claimed invention or exceeding its scope. Accordingly, it should be understood that the drawings and specification herein are provided by way of example to facilitate understanding of the invention and should not be construed as limiting its scope.

Claims

1. A method for treating a patient's disease state, comprising: identifying two lumens of the patient for the purpose of shunting to improve the disease state of the patient; placing a shunt device between the two lumens; fixing the shunt device to the two lumens by expanding both ends of the shunt device and shortening the shunt device; wherein the expansion and shortening fix the shunt device between the two lumens and shunt the two lumens.

2. The method according to claim 1, wherein the disease state is one of the group consisting of pulmonary hypertension, heart failure, hypertension, renal insufficiency, fluid volume overload, hypertrophic cardiomyopathy, valvular regurgitation, and a number of congenital diseases.

3. The method according to claim 1, wherein the shunt device comprises a stent-like device.

4. The method according to claim 1, wherein the expansion and shortening are generated by inflating a balloon disposed inside the shunt device.

5. The method according to claim 1, wherein the expansion and shortening are generated by self-expansion of the shunt device.

6. The method according to claim 1, wherein the degree of expansion and the degree of shortening are determined by different sizes of cells of the stent-like structure of the shunt device.

7. The method according to claim 6, wherein the different cell sizes are composed of cell sizes that gradually increase from the middle of the stent-like structure to the end extending in the axial direction of the stent-like structure.

8. The method according to claim 1, wherein the two lumens are separated by a common wall of tissue.

9. The method according to claim 1, wherein the shunt device is coated with a material.

10. The method according to claim 8, wherein the common wall is compressed between the opposing expanded walls as a result of the expansion and shortening.

11. The method according to claim 1, wherein parameters related to the disease state are measured before placing the shunt device and after the expansion and shortening.

12. A method for placing a prosthesis in a patient, comprising: placing the prosthesis in a biological passage; 1) radially expanding the distal and proximal ends of the prosthesis relative to the middle of the prosthesis, and 2) shortening the length of the prosthesis such that the distal and proximal ends of the prosthesis engage tissue surrounding the biological passageway, the step of radially expanding the prosthesis; wherein the prosthesis forms a shunt passageway between a first body cavity and a second body cavity. **Claim 13** The method of claim 11, wherein the prosthesis is a laser cut tubular structure having a plurality of cells that have a greater length near the proximal and distal ends of the prosthesis than at the middle of the prosthesis when the prosthesis is in a radially compressed configuration. **Claim 14** The method of claim 11, wherein the step of radially expanding the prosthesis further comprises expanding a balloon under the prosthesis, the balloon expanding in an hourglass shape. **Claim 15** The method of claim 11, wherein the prosthesis is a shunt having a tubular coating disposed along at least a portion of the length of the prosthesis. **Claim 16** The method of claim 11, wherein the prosthesis is a device having a coating layer that substantially blocks an internal passageway of the shunt. **Claim 17** A prosthesis for treating a patient, comprising a tubular structure having a radially compressed configuration and a radially expanded configuration, wherein the radially expanded configuration includes an expanded state of the distal and proximal ends and a shortened length, wherein the expanded state and the shortened length are sufficient to secure the tubular structure between tissues of two lumens of the patient. **Claim 18** The prosthesis of claim 17, wherein the tubular structure comprises a plurality of struts whose length increases away from the middle of the tubular structure towards the distal and proximal ends. **Claim 19** The prosthesis of claim 18, wherein the struts form a plurality of cells, and wherein the plurality of cells have a length that increases away from the middle of the tubular structure towards the distal and proximal ends when the tubular structure is in its radially compressed configuration. **Claim 20** The prosthesis according to claim 19, having a radially compressed length of about 30 mm, a radially compressed diameter of about 2.2 mm, a proximally and distally expanded diameter of about 8 mm, and an intermediate diameter expanded radially to about 4 mm.

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