Stent retention

Abstract

To provide suitable stent retention.SOLUTION: A system and method for a stent delivery system, the delivery system having a catheter 530 and a balloon 520, 525 coupled to a distal portion of the catheter. The catheter with the radially expandable member is inserted into the cavity in the mold. Heat and pressure are applied for a period of time to inflate the balloon and impart a shape memory to a portion of the balloon. The balloon is removed from the mold cavity with shape memory.SELECTED DRAWING: Figure 5E

Description

[Technical Field]

[0001] (Priority Claim) This application is a PCT application claiming the benefit of U.S. Provisional Application No. 62 / 988,135, filed March 11, 2020, the entire disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0002] The present invention relates to medical devices, and more particularly to the stenting and treatment of branched blood vessels. Stents are implantable scaffolds that are typically delivered percutaneously and deployed within veins, arteries, or other tubular body organs to treat occlusions, stenoses, aneurysms, collapsed, dissected, or weakened, diseased, or abnormally dilated blood vessels or vessel walls. Stents radially expand in situ, thereby dilating and / or supporting the blood vessel or body organ wall. In particular, stents are very commonly implanted within the coronary arteries, heart, lungs, neurovascular, peripheral vascular, kidney, gastrointestinal tract, and reproductive system, and have been successfully implanted within the urinary tract, bile duct, esophagus, tracheobronchial tree, and brain to strengthen these body organs. [Background technology]

[0003] Stents are commonly used to restore vascular patency, thereby allowing blood to flow through blocked vessels. Stents are used to treat stenotic lesions in blood vessels, such as coronary arteries, which supply oxygen-rich blood to the heart or other parts of the body. In addition, stents can help reduce symptoms such as angina and treat myocardial infarction. Stents are generally inserted percutaneously by catheter through an artery, such as the femoral, radial, or brachial artery; upon reaching the site of deployment, the stent expands, reopening the vessel lumen and supporting the vessel wall, and the catheter is removed, leaving the stent in place.

[0004] Conventional stent technology is relatively well developed. Conventional stent designs typically feature a single type of straight, porous structure, configuration, or pattern that is repetitive throughout translation along the longitudinal axis. In many stent designs, the repetitive structure, configuration, or pattern has struts and connecting balloon catheter segments that can obstruct blood flow in the vessel. Furthermore, the configuration of struts and connecting balloon catheter segments can interfere with post-operative use of the device to treat the vessel. Summary of the Invention [Means for solving the problem]

[0005] Therefore, given the challenges of current stent manufacturing and stent technology used to treat vascular conditions, there exists a need for improved stent delivery systems, delivery methods, and processes. At least some of these objectives will be met by the present invention.

[0006] Detailed Description of the Invention The present invention generally relates to improving stent delivery systems, delivery methods, and manufacturing techniques to allow for more precise vascular treatment and a lower likelihood of complications. For example, these systems and methods may be advantageous for reducing the risk of damaging surrounding tissue during distal advancement through a vessel. However, this is not intended to be limiting, and one skilled in the art will understand that the devices and methods described herein may be used to treat other areas of the body. [Brief explanation of the drawings]

[0007] In the drawings, which are not necessarily drawn to scale, like numbers may describe similar components in different views. Like numbers with different suffixes may represent different instances of similar components. Several embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.

[0008] [Figure 1]FIG. 1 illustrates a side view of a delivery system having a mother catheter and a daughter catheter.

[0009] [Figure 2A] FIG. 2A illustrates a stent delivery system within a guide catheter or introducer sheath.

[0010] [Figure 2B] FIG. 2B illustrates the stent edges hooking onto the edges of the introducer sheath or guide catheter of FIG. 2A.

[0011] [Figure 2C] FIG. 2C illustrates the stent edges contacting tissue upon delivery within a vessel.

[0012] [Figure 3A] FIG. 3A illustrates a side view of a radially expandable member positioned within a mold.

[0013] [Figure 3B] FIG. 3B illustrates a side view of the radial expansion of the radially expandable member within the mold of FIG. 3A.

[0014] [Figure 3C] FIG. 3C illustrates a side view of processing of the radially expandable member while in the mold.

[0015] [Figure 3D] FIG. 3D illustrates a side view of a collapsed radially expandable member within a mold.

[0016] [Figure 4A] FIG. 4A illustrates a side view of a stent loaded onto a radially expandable member after processing in a mold.

[0017] [Figure 4B] FIG. 4B illustrates a side view of the pillows that protect the stent from engaging the edge of the sheath.

[0018] [Figure 5A] FIG. 5A illustrates a side view of a pillow on the proximal end of a radially expandable member.

[0019] [Figure 5B] FIG. 5B illustrates a side view of a pillow on the distal end of the radially expandable member.

[0020] [Figure 5C] FIG. 5C illustrates a side view of pillows on the proximal and distal ends of the radially expandable member.

[0021] [Figure 5D] FIG. 5D illustrates another view of FIG. 5C after it has been removed from the mold.

[0022] [Figure 5E] FIG. 5E illustrates a side view of a stent loaded onto a first catheter.

[0023] [Figure 6A] FIG. 6A illustrates a distal portion of another stent delivery system.

[0024] [Figure 6B] FIG. 6B illustrates the stent of FIG. 6A partially crimped onto a delivery system.

[0025] [Figure 6C] FIG. 6C illustrates the stent of FIG. 6B further crimped onto a delivery system.

[0026] [Figure 6D] FIG. 6D illustrates pillowing of the radially expandable member in the stent delivery system of FIG. 6C.

[0027] [Figure 6E]FIG. 6E illustrates the insertion of a second catheter through the stent of FIG. 6D prior to the third crimping of the stent.

[0028] [Figure 6F] FIG. 6F illustrates a side view of FIG. 6E inserted into a die for a third crimp. DETAILED DESCRIPTION OF THE INVENTION

[0029] Aspects of the subject technology address some of the potential problems with conventional stent delivery systems, which can have limitations and challenges in stent retention during retraction of the stent-loading catheter back into the introducer sheath or guide catheter and during delivery of the stent delivery system through a vessel. For example, a potential problem with conventional stent delivery systems can occur when the proximal edge of the stent catches on the distal edge of the introducer sheath or guide catheter as the stent is being retracted proximally, causing the stent to become dislodged and / or damaged. Furthermore, upon introduction of the catheter through a vessel, the distal edge of the stent may contact tissue during distal advancement, or the proximal edge of the stent may contact tissue during proximal retraction, thereby causing vessel damage or plaque undermining. Tissue damage can occur around curves in tortuous vessels. Examples of stent delivery systems disclosed herein can reduce the risk of a stent becoming caught in an introducer sheath or guide catheter or causing tissue damage while being introduced or otherwise manipulated. These challenges can be alleviated using a stent delivery system with "pillow" regions on either side of the stent. Pillow regions are enlarged protrusions (e.g., ridges) that may be dumbbell-shaped and can protect the edges on either side of the stent from becoming dislodged from the catheter or damaging surrounding tissue upon insertion and retraction.

[0030] The proximal or distal edges of the stent may be protected from dislodgement and tissue damage through the use of a radially expandable member. In any of the embodiments discussed herein, the radially expandable member may be a balloon. The balloon member may have ridges on both ends of the stent that may have shape memory. The shape memory is induced by heat and pressure over time, and the shape may be retained after several cycles of inflation and deflation. Additionally, the balloon may be deflated but still maintain a protective shield (e.g., protrusions) due to the shape memory, which provides protection against the proximal or distal edges of the stent contacting the sheath or contacting tissue. Thus, the balloon or other radially expandable member may be deflated and re-inflated while still providing pillowing. The memory may last for one or more, two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, or more than ten inflation / deflation cycles before the memory is lost. The radially expandable member in this or any embodiment may be a balloon or another expandable member used in the deployment of a stent.

[0031] Generally, the methods disclosed herein may provide protection to a stent by inducing shape memory in a balloon. For example, inducing shape memory may be accomplished by using inserting the balloon into a mold. The mold may be made of metal, polymer, or ceramic, a combination thereof, or any other material known in the art. In any embodiment, all or a portion of the balloon is placed within the mold, and a portion of the balloon may be expanded within the mold while another portion is constrained inside or outside the mold. The mold may be a hand crimper, an iris, or an elongated shaft (e.g., made of metal, polymer, or ceramic). The balloon may be treated (e.g., heat, pressure) during expansion, which induces shape memory in the balloon. Throughout this application, references to D refer to "distal" and references to P refer to "proximal."

[0032] Reference will now be made in detail to specific embodiments of the present disclosure. In the following description, specific details are set forth to provide a thorough understanding of the subject matter. It will be understood that any embodiment may be practiced without some or all of these specific details, and that no specific feature is critical or limiting.

[0033] Stent retention

[0034] 1 shows a side view of a stent delivery system 100 for retaining a stent, according to an optional embodiment. The system includes a first catheter 120 (e.g., also referred to as a mother catheter or main branch catheter) with a first elongated shaft and hub 122, and a second catheter 110 (e.g., also referred to as a side branch catheter, daughter catheter) with a second elongated shaft and hub 112. The term "mother" may refer to a catheter, balloon, or stent in the main branch, while the term "daughter" may refer to a catheter, balloon, or stent in the side branch. Thus, the term "mother" may be substituted for the term "main branch," and the term "daughter" may be substituted for the term "side branch." The first catheter 120 has a first balloon 130 (e.g., mother balloon) disposed on a distal portion of the first catheter 120, and the second catheter 110 has a second balloon 140 (e.g., daughter balloon) disposed on a distal portion of the second catheter 110. A stent (not shown) may be disposed over the mother balloon, the daughter balloon, or a stent may be disposed over both balloons.

[0035] 2A shows a side view of a stent delivery system 200 for retaining a stent 230, showing the proximal side P and distal side D of the stent delivery system 200. The system for the stent includes a delivery catheter 220, a balloon 245 on a distal portion of the catheter 220, and a stent 230 disposed over the balloon. The balloon 245 has a working length that can match, be longer, or shorter than the length of the stent 230. The balloon 245 may include proximal and distal shoulder regions connected to the catheter 220, which is slidably disposed through a guide catheter 210 (e.g., a sheath). An introducer sheath or guide catheter 210 is provided through which the catheter 220 and stent 230 may be retracted proximally such that the stent is protected by the guide catheter 210 during delivery.

[0036] 2B shows a side view of the catheter 220, balloon 245, and stent 240 of FIG. 2A being retracted proximally, as indicated by arrow 247, through the sheath or guide catheter 210. The blunt proximal edge of the stent 240 may contact the distal edge of the sheath or guide catheter 210 and induce a compressive force on the stent 240. The stent may become deformed and / or become partially or completely dislodged from the catheter. Additionally, the stent may be damaged, rendering it unusable. This may be particularly undesirable when the stent is delivering a therapeutic agent, such as paclitaxel or rapamycin, or any other drug, because the drug may also be dislodged from the stent when the stent catches on the sheath edge.

[0037] 2C shows a side view of catheter 260, balloon proximal portion 270 and balloon distal portion 282, and stent 280 being delivered through blood vessel 250. In some embodiments, blood vessel 250 may have an arcuate region, and blunt proximal end 290 of stent 280 may contact the wall of blood vessel 250 as the catheter is retracted proximally through the vessel, as indicated by arrow 252. The area of ​​contact of blunt proximal end 290 may cause tissue damage. Damage to tissue may also occur during distal advancement through the vessel, as indicated by arrow 284, when distal end 286 of stent 280 may contact blood vessel 250.

[0038] Several embodiments are disclosed herein that protect one or more edges of a stent to form a protective barrier.

[0039] Shape memory function

[0040] 3A-3D show an example of a process for forming the proximal portion of the balloon.

[0041] FIG. 3A shows a side view of a system 300 for forming a balloon to help protect and retain a stent on a stent delivery catheter. The stent delivery system includes a stent delivery catheter having a first catheter 330 and a folded balloon 340 on the first catheter 330. The balloon 340 may have pleats or folds 342 when the balloon 340 is in a neutral (e.g., unexpanded) state. The balloon is fixedly attached to the first catheter 330. The first catheter 330 and the balloon 340 are inserted into a mold 310. The mold 310 may be made of ceramic (e.g., glass), polymer, or metal, or a combination thereof, or any other material known in the art. In this or any embodiment, a portion of the balloon 340 may be constrained by the mold 310. The mold 310 includes a first cavity 380, a second cavity 395, and a transition region, such as a tapered portion 390, that may be disposed therebetween. The first cavity of the mold 310 is cylindrical, and the second cavity of the mold 310 is also cylindrical, with the first cavity 380 having a larger diameter than the second cavity 395. The mold 310 may have the same length as the balloon 340 or a longer length than the balloon 340. A proximal portion of the balloon 340 may be disposed within the first cavity 380, and a distal portion of the balloon 340 may be disposed within the second cavity 395. In addition, a portion between the proximal portion of the balloon 340 and the distal portion of the balloon 340 may be disposed within the tapered portion 390. The distal portion of the balloon 340 is disposed within the second cavity of the mold 310 and is constrained by the mold, preventing expansion of the balloon 340 (or substantially preventing any expansion). The first cavity 380 has a diameter greater than the folded balloon 340 in its unexpanded state. The first cavity 380 may have a larger diameter than the fully expanded balloon 340, which may allow the balloon 340 to fully expand.Alternatively, the first cavity 380 may have a smaller diameter than the balloon 340 in its fully expanded state, which prevents the balloon 340 from further expanding (e.g., not fully expanding) after it abuts the inner wall of the first cavity 380. The proximal portion of the balloon 340 may expand to create a pillow region. The pillow region creates a protective cover for the edges of the stent during introduction and retraction into and out of the vessel. The first cavity 380 is greater than or equal to the length of the pillow region on the proximal portion of the balloon 340. The second cavity 395 has a diameter sized to receive the distal portion of the balloon 340; however, this constrains the distal portion of the radially expandable portion and does not allow expansion when the balloon is heated and pressurized. The second cavity 395 is greater than or equal to the length of the distal portion of the balloon 340.

[0042] 3B shows a side view of stent delivery system 300 when the balloon is pressurized as shown in FIG. 3A. Balloon 340 may be expanded within mold 310. Expansion of balloon 340 occurs when heat is applied to mold 310 and pressure is applied, expanding balloon 340. The heat, pressure, and dwell time in the mold will be discussed below. In one embodiment, a proximal portion of balloon 340 is expanded within mold 310, while a distal portion of balloon 340 is constrained to open as described above.

[0043] The entire balloon 340 may be subjected to heat and pressure within the mold 310; however, only the proximal portion of the balloon 340 may expand, as the distal portion of the balloon 340 may be constrained and therefore unable to expand. Additionally, an optional protective sheath 335, as shown in FIG. 4A below, may be applied to a portion of the balloon 340 within the mold to prevent expansion. The constrained portion of the balloon 340 has a smaller diameter than the unconstrained portion of the balloon 340, as shown in FIG. 4A.

[0044] In any embodiment, the proximal portion of the balloon 340 may be inflated to contact the inner wall of the first cavity 380, while the distal portion of the balloon 340 is constrained and not inflated. The proximal portion of the balloon 340 may be fully inflated, which radially expands to the full diameter of the balloon 340 without reaching the inner wall of the first cavity 380. Alternatively, the balloon 340 may be partially inflated, and further expansion of the balloon 340 is prevented upon reaching the inner wall of the first cavity 380. Alternatively, the balloon 340 may be partially expanded such that it does not reach its full diameter or contact the inner surface of the mold wall.

[0045] FIG. 3C shows a side view of the treatment of the balloon while it is placed in the mold. In this example, the entire balloon 340 may be placed in the mold and undergo treatment, but only the proximal portion of the balloon 340 expands to contact the larger proximal diameter of the mold; the distal portion of the balloon 340 does not expand because it is constrained by the mold. Treatment may include applying heat 360, pressure 370, or both for a predetermined time. In any example, the added heat 360, pressure 370, or both may induce shape memory in the balloon 340. Once a stent is placed on the balloon 340, the shape memory may protect the edges of the stent. The shape memory may be ridges or dumbbells protruding from the edges of the stent that retain their shape after a series of inflations and deflations of the balloon 340. Heat 360, pressure 370, or both are applied for a predetermined time, which will induce shape memory in the balloon 340 within the mold. In any embodiment, heat 360 may be between 40°C and 80°C, or between 50°C and 70°C, or between 55°C and 65°C, or the heat may be 60°C. In any embodiment, pressure 370 may be between 100 psi and 150 psi, or between 110 psi and 140 psi, or between 110 psi and 130 psi, or between 115 psi and 130 psi, or between 120 psi and 125 psi, or between 120 psi and 125 psi. Dwell time may be the amount of time that heat 360 and pressure 370 are applied. In any embodiment, dwell time may be between 15 seconds and 2 minutes, or between 15 seconds and 1 minute, or between 30 seconds and 1 minute, or between 1 minute and 1 minute 30 seconds, or between 1 minute 30 seconds and 2 minutes, or between 30 seconds, 45 seconds, 1 minute, 1 minute 15 seconds, 1 minute 30 seconds, 1 minute 45 seconds, or 2 minutes. Any combination or permutation of time, temperature, or pressure ranges may be used to treat the balloon. While heat 360 and pressure 370 are applied to the entire radially expandable component, only the expanded proximal portion of balloon 340 will undergo shape memory, as the distal portion of balloon 340 remains constrained and unexpanded. Shape memory will allow radially expandable portion 340 to retain the protruding pillow region even after it is fully deflated.The proximal portion of the balloon 340 that undergoes shape memory will be larger in diameter than the distal portion of the constrained balloon 340. The shape memory added to the proximal portion of the balloon 340 can last for more than 2, 3, 4, 5, 6, 7, 8, 9, or 10 cycles. A cycle is identified by inflation and deflation of the balloon during use on a patient.

[0046] 3D shows a side view of deflation of stent delivery system 300. Here, balloon 340 is fully deflated but has shape memory that creates a bulge on the proximal portion of balloon 340. In another embodiment, balloon 340 is only partially deflated to retain a larger bulge on the edge of a stent (not shown) for insertion into the body. First catheter 330 coupled to balloon 340 is then removed from mold 310, and a stent may then be added to the delivery catheter.

[0047] 4A shows a side view of a stent delivery system 400 loaded into a stent 410 after forming a shape memory region or regions in the balloon according to any of the embodiments disclosed herein. In any embodiment, the stent 410 is loaded onto the balloon 340 in such a way that the proximal end of the stent abuts the pillow or protruding portion 344 of the balloon 340. The "pillow effect" of the proximal portion of the balloon 340 has a larger diameter than the stent 410. The sheath 335 is pulled over the balloon 340 so that the edges of the sheath pass over the balloon 340 without catching on the edges of the stent. The balloon 340 may be collapsed for removal through the sheath 335, or the balloon 340 automatically collapses as it is removed through the sheath 335, however, the shape memory remains intact.

[0048] 4B shows continued proximal retraction 377 of the delivery catheter and stent 410 of FIG. 4A above into sheath 335, with protruding region 344 of balloon 340 protecting the proximal blunt edge of stent 410 as the stent is further retracted proximally, so that stent 410 does not catch on sheath 335 as the delivery catheter is retracted into sheath 335. Balloon 340 covers the proximal edge of stent 410, preventing it from catching on sheath 335. Additionally, the proximal edge of stent 410 is protected from dislodgement or tissue damage during proximal retraction 377 through the vessel.

[0049] FIG. 5A shows a side view of the loading of the proximal portion 520 of a balloon into a mold 510 and protective sheath 560. FIG. 5A is another example of imparting shape memory to the proximal portion 520 of a balloon similar to FIG. 4B above, with the primary difference being the mold 510 and protective sheath 560 used during processing. In the stent delivery system 500, the mold 510 may be an elongated tube. The mold may be made of metal, polymer, or ceramic, a combination thereof, or any other material known in the art. Alternatively, the mold 510 may be a channel formed by a collapsible iris of a crimping system. Alternatively, the mold 510 may be a plastic tube. In the stent delivery system 500, the first catheter 530 has a distal radiopaque marker 540 and a proximal radiopaque marker 550. The distal radiopaque marker 540 and the proximal radiopaque marker 550 may provide assistance in positioning the stent between the radiopaque markers. The proximal portion 520 of the balloon may have a constrained portion and a portion that remains unconstrained. In this example, the proximal portion of the balloon remains unconstrained. The distal portion of the balloon may be constrained using a protective sheath 560. The protective sheath 560 may be made of metal, plastic, or any other material known in the art. The protective sheath 560 may restrict a portion of the balloon from expanding. Heat and pressure may be applied for a period of time to induce expansion of the unconstrained proximal portion 520 of the balloon using any of the processing parameters previously described above. The proximal portion 520 of the balloon may expand until it reaches the wall of the mold 510. The diameter of the mold 510 may determine the diameter of the pillow portion of the proximal portion 520 of the balloon. Expansion of the proximal portion 520 induces a shape memory in the proximal portion 520. The shape memory may be a ridge on the proximal end of the balloon or a pillow as described above in the shape of a dumbbell. The shape memory may withstand several cycles of inflation and deflation (as previously described above) of the proximal portion 520. The stent may be loaded onto the balloon so that the proximal edge of the stent abuts the pillow.The shape memory of the proximal portion 520 of the balloon may protect the stent from becoming dislodged or damaged from retraction of the catheter or causing trauma to the tissue, as previously explained above.

[0050] 5B shows another embodiment similar to FIG. 5A, however, in this embodiment, the distal portion 525 of the balloon is endowed with shape memory. In the stent delivery system 500, a protective sheath 560 is loaded onto the proximal end of the first catheter 530 and over the distal portion 525 of the balloon. Two radiopaque markers may be coupled to the first catheter 530. A proximal radiopaque marker 550 and a distal radiopaque marker 540 are located on the distal portion of the first catheter 530, with the proximal radiopaque marker 550 being proximal to the distal radiopaque marker 540. In any embodiment, the protective sheath 560 may constrain the proximal portion 523 of the distal portion 525 of the balloon and leave the distal portion 527 of the distal portion 525 of the balloon unconstrained. Additionally, the constraining sheath 532 may restrain a further distal portion 529 of the balloon distal portion 525 from expanding, while a more proximal portion of the balloon distal portion 525 is unconstrained and allowed to expand, forming a pillow distal to the distal radiopaque marker 540 where the distal edge of the stent would be. As explained above, heat may be applied to the mold 510 and pressure may be applied to the balloon distal portion 525 to inflate it, to induce shape memory in the balloon distal portion 525. The shape memory may be a bulge or a pillow. The shape memory may withstand several cycles of inflation and deflation of the balloon distal portion 525. The stent may be loaded onto the balloon such that the distal edge of the stent abuts the balloon distal portion 525. The shape memory of the balloon distal portion 525 may protect the tissue of the vessel upon delivery.

[0051] FIG. 5C illustrates another embodiment for inducing shape memory. In FIG. 5C, shape memory is induced in both the proximal portion 520 of the balloon, as illustrated in FIG. 5A above, and the distal portion 525 of the balloon, as illustrated in FIG. 5B above. In any embodiment, the pillow portion of the distal portion 525 of the balloon may be smaller in diameter than the pillow portion of the proximal portion 520 of the balloon. This may be due to a lower need for pillowing to protect surrounding tissue. Alternatively, the pillow portion of the proximal portion 520 of the balloon may have a smaller diameter than the pillow portion of the distal portion 525 of the balloon. This may be due to less concern about tissue damage to the surrounding vessel upon insertion and retraction and greater concern about stent dislodgement upon insertion and retraction. Alternatively, the pillow regions of the proximal portion 520 of the balloon and the distal portion 525 of the balloon may have the same size diameter. In this or any embodiment, a protective sheath 560 may be placed between the distal balloon portion 525 and the proximal balloon portion 520 to prevent the intermediate portion from expanding under heat and pressure. Heat, pressure, and dwell time ranges are discussed above. The sheath 560 may be made from any of the materials discussed above. The first catheter 530 may have two or more radiopaque markers on the distal end of the shaft. The distal radiopaque marker 540 and the proximal radiopaque marker 550 may provide assistance with alignment of the protective sheath 560 or the stent. The stent may be positioned between the radiopaque markers. The distal and proximal portions of the balloons 525 and 520, respectively, may expand into contact with the mold 510 when heat and pressure are applied.

[0052] In another embodiment, when the protective sheath 560 is loaded into the mold 510 and placed between the distal portion 525 of the balloon and the proximal portion 520 of the balloon, the proximal portion 520 or the distal portion 525 of the balloon may be fully expanded or partially expanded. When the distal portion 525 and the proximal portion 520 of the balloon are partially expanded, they may not contact the mold 510. Alternatively, the distal portion 525 of the balloon may contact the mold when it is fully expanded, while the proximal portion 520 of the balloon does not contact the mold 510 when it is partially expanded. Or conversely, the proximal portion 520 of the balloon may contact the mold 510 when it is fully expanded, while the distal portion 525 of the balloon does not contact the mold 510 when it is partially expanded. Whether the distal or proximal portions 525 and 520 of the balloon are fully or partially expanded may depend on the desired diameter size of the distal or proximal portion. For example, if a large proximal portion 520 is desired and a smaller distal portion 525 is desired, the proximal portion 520 may be fully expanded and the distal portion 525 may be partially expanded. In any embodiment, the distal and proximal portions 525 and 520 of the balloon may be expanded simultaneously. Alternatively, the proximal portion may be expanded before the distal portion. Alternatively, the distal portion may be expanded before the proximal portion.

[0053] 5D shows the embodiment after the balloon has been removed from the mold 510 and the protective sheath 560 has been removed. Shape memory is induced in the proximal and distal portions 520 and 525 of the balloon, allowing them to withstand a series of inflations and deflations of the balloon (e.g., balloon), as discussed above. After shape memory is induced, a stent may be loaded onto the first catheter 530. The stent may be positioned between the distal radiopaque marker 540 and the proximal radiopaque marker 550. A sheath 570 may be inserted over the balloon.

[0054] 5E shows the embodiment after a stent 580 has been loaded onto a first catheter 530 with a proximal portion 520 of the balloon and a pillow portion of a distal portion 525. The stent 580 is positioned between a proximal radiopaque marker 550 and a distal radiopaque marker 540.

[0055] Combined stent crimping and shape memory formation

[0056] 6A-6F show different steps in crimping a stent 610 as it is loaded over a balloon 620 attached to the distal end of a first catheter 630 for delivery using a delivery system 600. FIG.

[0057] FIG. 6A shows a system 600 for crimping a stent 610 and expanding a balloon 620 to form one or more of the pillow regions previously described above. In FIG. 6A, the stent 610 is loaded over a balloon 620 that is attached to the distal end of a first catheter 630 for delivery. The working length of the balloon 620 matches the length of the stent 610, while the shoulder 635 may extend slightly beyond the stent. In some embodiments, the balloon 620 may be longer than the stent 610 and may extend past the stent 610 on both sides. The stent 610 may have side holes 645, or in some embodiments where side holes are used, the spaces between the struts on the stent may be used as side holes. The first catheter 630 may have two or more radiopaque markers, which may aid in stent alignment over the balloon 620. In this example, there are two radiopaque markers: a distal radiopaque marker 640 and a proximal radiopaque marker 650 that is more proximal than the distal radiopaque marker 640. Both markers may be on the distal portion of the first catheter.

[0058] In FIG. 6B , a first partial crimp may be applied to the distal portion 615 of the stent 610. The partial crimp provides alignment of the stent on the balloon 620 and prevents longitudinal movement of the stent 610 so that the stent remains positioned between the radiopaque markers 640, 650. In this or any embodiment, the distal crimp may extend from the distal-most end of the stent to the side hole 645. In any embodiment, the proximal portion 617 of the stent 610 may not be crimped. The distal crimp of the distal portion 615 may aid in alignment between the distal radiopaque marker 640 and the proximal radiopaque marker 650 by holding the stent in place. The distal crimp may be performed by light hand crimping or with any other crimping tool. Alternatively, the distal crimp may be performed by inserting the system 600 into a crimping iris, which applies pressure and heat for a given period of time. A protective coating may be applied to the proximal portion 617 of the stent 610 to prevent expansion. Alternatively, or in addition, the proximal portion 617 is not inserted into the iris to be crimped.

[0059] In FIG. 6C, a full crimp is applied to the system 600, embedding the stent 610 within the balloon 620. A full crimp may be applied to the distal portion 615. A full crimp embeds the stent 610 within the balloon 620, preventing migration or dislodgement of the stent 610. A full crimp may impart some shape memory to the distal portion 615 when heat and pressure are applied for a period of time (see operating parameters discussed above); however, because the dwell time for crimping the stent is relatively short, full expansion may not occur. Embedding the stent within the balloon prevents any longitudinal movement of the stent 610 relative to the balloon 620. Additionally, a full crimp eliminates movement during transvascular delivery and routine handling and manipulation of the device. A protective coating may be applied to the proximal portion 617 of the stent 610 to prevent expansion. Alternatively, or in addition, the proximal portion 617 may not be inserted into the iris to be crimped.

[0060] FIG. 6D shows the system of FIG. 6C in which system 600 is inserted into a mold (as described above) and heat and pressure are applied for a dwell time to form a shape memory. The mold may be any of the materials or shapes discussed herein. Heat is applied to the mold and pressure is applied to the balloon, and in response, a portion of the balloon partially expands, forming a dumbbell shape. This may cause a proximal portion 670 of the balloon to expand. Alternatively, this may cause a distal portion 660 of the balloon to expand. In this example, the heat in the mold and pressure on the balloon cause the proximal and distal portions 670 and 660 of the balloon to become pressurized and expand. The proximal portion 670 may be larger in diameter than the distal portion 660. Alternatively, the distal portion 660 may be larger in diameter than the proximal portion 670. Alternatively, the distal and proximal portions 660 may have the same diameter. The heat, pressure, and dwell time that imparts the shape memory may create protruding ridges on the balloon that cover the proximal or distal or both ends of the stent 610. Alternatively, the ridges may be bulbous or dumbbell-shaped. The ridges may be maintained even after several cycles of inflating and deflating the balloon.

[0061] FIG. 6E is a side view rotated 90 degrees from FIG. 6D with a side hole at the top of the stent 610. A second catheter 690 (e.g., a daughter catheter or side branch catheter) is inserted into the side hole 645. The second catheter 690 may contain a second balloon 697. In some embodiments, the second catheter may contain a second stent disposed over the second balloon 697. The first catheter may have a hollow exchange port tube 695 to aid in alignment of the second catheter 690 with the side hole 645. The hollow exchange port 695 may be made of glass, plastic, rubber, or any suitable combination thereof. In this embodiment, the second catheter 690 has a distal end that exits the optional side hole 645 after being advanced through the hollow exchange port 695 and through the proximal end of the stent 610. Insertion of the second catheter 690 through the side hole 645 of the stent 610 can cause an overlap between the first catheter 630 and the second catheter 690. The second catheter 690 may be introduced through the stent 610 through existing openings between adjacent struts in the sidewall of the stent 610.

[0062] Figure 6F shows the system 600 of Figure 6E inserted into a mold 699. Heat and pressure applied to the system as discussed above crimps the stent to the working lengths of the balloons on both the first catheter 630 (e.g., mother catheter) and the second catheter 690 (e.g., daughter catheter). The distal and proximal regions 660 and 670 may undergo a reduction in diameter because they will be reduced in size; however, the dumbbell shape will remain due to the shape memory imparted to these regions of the balloon. The various vertical arrows illustrate the compressive force and movement of the mold 699 that will crimp the system 600 together. Notes and Examples

[0063] The following non-limiting examples detail certain aspects of the present subject matter to, among other things, solve the problems and provide the benefits discussed herein.

[0064] Example 1 provides a stent delivery system comprising a first elongate shaft and a first radially expandable member disposed on a distal portion of the first elongate shaft, the first elongate shaft further comprising a distal radiopaque marker on the distal portion of the first elongate shaft and a proximal radiopaque marker disposed on the distal portion of the first elongate shaft, the proximal marker being proximal to the distal marker; and inserting the first radially expandable member into a cavity in a mold; and inserting the first radially expandable member into a cavity in a mold to expand the distal portion of the stent in the first radially expandable member. a first radially expandable member, the first radially expandable member being partially crimped to hold the stent in alignment between the proximal and distal radiopaque markers; a first radially expandable member being fully ...

[0065] Example 2 is the method of example 1, wherein the first radially expandable member is a balloon, and imparting shape memory further includes constraining a portion of the first radially expandable member by a mold while another portion of the first radially expandable member is not constrained by the mold.

[0066] Example 3 is a method according to any of Examples 1-2, wherein the first radially expandable member comprises a proximal portion, a distal portion, and an intermediate portion disposed therebetween, and wherein imparting shape memory further comprises imparting shape memory to the proximal portion without imparting shape memory to the distal portion or the intermediate portion, or imparting shape memory further comprises imparting shape memory to the distal portion without imparting shape memory to the proximal portion or the intermediate portion, or imparting shape memory further comprises imparting shape memory to the distal portion and the proximal portion without imparting shape memory to the intermediate portion.

[0067] Example 4 is the method described in any of Examples 1-3, wherein imparting shape memory to the proximal portion without imparting shape memory to the distal portion or the intermediate portion further comprises forming the proximal portion of the first radially expandable member such that the proximal portion has a diameter greater than the diameter of the distal portion of the first radially expandable member, or wherein imparting shape memory to the distal portion and the proximal portion without imparting shape memory to the intermediate portion further comprises forming the proximal portion of the first radially expandable member such that the proximal portion may have a diameter less than the diameter of the distal portion of the first radially expandable member.

[0068] Example 5 is the method of any of Examples 1-4, wherein crimping the distal portion of the stent includes partially crimping the distal portion, and wherein crimping the distal portion of the stent further includes a second crimping after the partial crimping, and wherein the second crimping further includes fully crimping the distal portion of the stent to the first radially expandable member without crimping a proximal portion onto the first radially expandable member.

[0069] Example 6 is the method of any of Examples 1-5, wherein crimping the distal portion of the stent further comprises fully crimping the distal portion of the stent to the first radially expandable member, and wherein crimping the distal portion of the stent further comprises a second full crimp after the full crimping, and wherein the second full crimping further comprises fully crimping the distal and proximal portions of the stent to the first radially expandable member.

[0070] Example 7 is the method of any of Examples 1-6, wherein the shape memory is maintained after multiple cycles of expanding and contracting the radially expandable member, and the shape memory comprises a bulbous region configured to abut an edge of the stent and provide a protective covering to the edge of the stent.

[0071] Example 8 is the method of any of Examples 1-7, wherein the bulbous region is configured to have a diameter greater than a diameter of the edge of the stent.

[0072] Example 9 is the method of any of Examples 1-8, further including, after full crimping, slidably positioning a second elongated shaft having a second radially expandable member under a proximal portion of the first stent and through a side hole of the stent, and simultaneously crimping the stent onto the first radially expandable member and the second radially expandable member.

[0073] Example 10 is the method described in any of Examples 1-9, wherein the first elongate shaft further comprises a hollow exchange port tube coupled to an outer surface of the first elongate shaft, the hollow exchange port tube having a lumen disposed therethrough, and inserting the second radially expandable member further comprises slidably disposing the second elongate shaft through the lumen of the hollow exchange port tube such that the second elongate shaft is aligned with the side hole of the stent.

[0074] Example 11 is the method of any of Examples 1-10, wherein the shape memory is maintained after multiple cycles of expanding and contracting the first radially expandable member, and the shape memory comprises a bulbous region configured to abut an edge of the stent and provide a protective covering to the edge of the stent.

[0075] Example 12 is a stent delivery system comprising a first elongate shaft and a first radially expandable member disposed on a distal portion of the first elongate shaft, the first elongate shaft further comprising a distal radiopaque marker on the distal portion of the first elongate shaft and a proximal radiopaque marker disposed on the distal portion of the first elongate shaft, the proximal marker being proximal to the distal marker; and a mold comprising a cavity, the first radially expandable member disposed in the cavity, and a stent, the stent being configured to include a distal radiopaque marker and a proximal radiopaque marker. A system for retaining a stent comprising: a mold disposed on a first radially expandable member so as to be positioned between the stent and a permeable marker, the stent having a proximal portion and a distal portion, the distal portion of the stent being fully crimped onto the first radially expandable member and the proximal portion not being crimped onto the first radially expandable member such that full crimping prevents axial movement of the stent during delivery; and a region of the first radially expandable member comprising a shape memory portion having a first bulbous region that abuts the edge of the stent to provide a protective covering to the edge of the stent.

[0076] Example 13 is the system of example 12, in which the first radially expandable member is a balloon.

[0077] Example 14 is a system described in any of Examples 12-13, wherein the first radially expandable member further comprises a proximal portion, a distal portion, and an intermediate portion disposed therebetween, and wherein the shape memory portion is applied to the proximal portion without the shape memory portion being applied to the distal portion or the intermediate portion, or the shape memory portion is applied to the distal portion without the shape memory portion being applied to the proximal portion or the intermediate portion, or the shape memory portion is applied to the distal portion and the proximal portion without the shape memory portion being applied to the intermediate portion.

[0078] Example 15 is the system of any of Examples 12-14, wherein when the shape memory portion is imparted to the proximal portion without shape memory being imparted to the distal portion or the intermediate portion, or when shape memory is imparted to the distal portion and the proximal portion without shape memory being imparted to the intermediate portion, the proximal portion of the first radially expandable member has a diameter greater than the diameter of the distal portion of the first radially expandable member.

[0079] Example 16 is the system of any of Examples 12-15, wherein the distal and proximal portions of the stent are fully crimped onto the first radially expandable member.

[0080] Example 17 is the system of any of Examples 12-16, wherein the shape memory portion is maintained after multiple cycles of expansion and contraction of the first radially expandable member.

[0081] Example 18 is a system described in any of Examples 12-17, wherein the stent has a side wall with a side hole extending therethrough, the first elongated shaft further comprises a hollow exchange port tube coupled to an outer surface of the first elongated shaft, the hollow exchange port tube having a lumen disposed therethrough, and the second elongated shaft is slidably disposed through the lumen of the hollow exchange port tube such that the second elongated shaft is aligned with the side hole of the stent.

[0082] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. The inventors also contemplate examples using any combination or permutation of those elements (or one or more aspects thereof) shown or described, either with respect to a particular example (or one or more aspects thereof) or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0083] In the event of inconsistency in usage between this document and any document so incorporated by reference, the usage in this document shall prevail.

[0084] The terms "a" or "an" are used herein, as is common in patent documents, to include one or more than one, regardless of any other instance or usage of "at least one" or "one or more." The term "or" is used herein to refer to non-exclusive, unless otherwise indicated, or "A or B" to include "A but not B," "B but not A," and "A and B." The terms "including" and "in The term "which" is used as the plain-English equivalent of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, i.e., systems, devices, articles, compositions, formulations, or processes that include elements in addition to those recited after such term in a claim are still deemed to fall within the scope of that claim. Also, in the following claims, the terms "first," "second," "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[0085] The above description is intended to be illustrative, not limiting. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be utilized, such as by those skilled in the art, upon review of the above description. The Abstract is provided to enable the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be construed as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of the disclosed embodiments. Thus, the following claims are incorporated herein as examples or embodiments into the Detailed Description, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full range of equivalents to which such claims are entitled. The present specification also provides, for example, the following items: (Item 1) 1. A method for retaining a stent, comprising: a stent delivery system comprising: a first elongate shaft; and a first radially expandable member disposed on a distal portion of the first elongate shaft, the first elongate shaft further comprising a distal radiopaque marker on the distal portion of the first elongate shaft; and a proximal radiopaque marker disposed on the distal portion of the first elongate shaft, the proximal marker being proximal to the distal marker; Inserting the first radially expandable member into a cavity in a mold; partially crimping a distal portion of the stent onto the first radially expandable member to hold the stent in alignment between the proximal and distal radiopaque markers; fully crimping a distal portion of the stent onto the first radially expandable member, wherein fully crimping embeds the stent onto the first radially expandable member; applying heat and pressure to the first radially expandable member while disposed within the cavity in the mold, thereby imparting shape memory to a portion of the first radially expandable member; A method comprising: (Item 2) the first radially expandable member is a balloon; and imparting the shape memory further comprises constraining a portion of the first radially expandable member by the mold while another portion of the first radially expandable member is not constrained by the mold. The method according to item 1. (Item 3) the first radially expandable member comprising a proximal portion, a distal portion and an intermediate portion disposed therebetween; or imparting shape memory further comprises imparting shape memory to the proximal portion without imparting shape memory to the distal portion or the intermediate portion; or imparting shape memory further comprises imparting shape memory to the distal portion without imparting shape memory to the proximal portion or the intermediate portion; and imparting the shape memory further comprises imparting the shape memory to the distal portion and the proximal portion without imparting the shape memory to the intermediate portion. The method according to item 1. (Item 4) imparting shape memory to the proximal portion without imparting shape memory to the distal portion or the intermediate portion further comprises forming the proximal portion of the first radially expandable member such that the proximal portion has a diameter greater than a diameter of the distal portion of the first radially expandable member; or imparting shape memory to the distal portion and the proximal portion without imparting shape memory to the intermediate portion further includes forming the proximal portion of the first radially expandable member such that the proximal portion can have a diameter smaller than a diameter of the distal portion of the first radially expandable member. The method according to item 3. (Item 5) Item 10. The method of item 1, wherein crimping the distal portion of the stent comprises partially crimping the distal portion, and wherein crimping the distal portion of the stent further comprises a second crimping after the partial crimping, and wherein the second crimping further comprises fully crimping the distal portion of the stent to the first radially expandable member without crimping the proximal portion onto the first radially expandable member. (Item 6) Item 10. The method of item 1, wherein crimping the distal portion of the stent further comprises fully crimping the distal portion of the stent onto the first radially expandable member, and wherein crimping the distal portion of the stent further comprises a second full crimp after the full crimping, and the second full crimping further comprises fully crimping the distal and proximal portions of the stent onto the first radially expandable member. (Item 7) Item 10. The method of item 1, wherein the shape memory is maintained after multiple cycles of expanding and contracting the radially expandable member, and the shape memory comprises a bulbous region configured to abut an edge of the stent and provide protective covering to the edge of the stent. (Item 8) 8. The method of claim 7, wherein the bulbous region is configured to have a diameter greater than a diameter of the edge of the stent. (Item 9) slidably disposing a second elongate shaft having a second radially expandable member under a proximal portion of the first stent and through a side hole of the stent after full crimping; simultaneously crimping the stent onto the first radially expandable member and the second radially expandable member; Item 1. The method of item 1, further comprising: (Item 10) the first elongate shaft further comprises a hollow exchange port tube coupled to an outer surface of the first elongate shaft, the hollow exchange port tube having a lumen disposed therethrough, and inserting the second radially expandable member further comprises: 10. The method of claim 9, comprising slidably positioning the second elongate shaft through a lumen of the hollow exchange port tube such that the second elongate shaft is aligned with a side hole of the stent. (Item 11) Item 10. The method of item 1, wherein the shape memory is maintained after multiple cycles of expanding and contracting the first radially expandable member, and the shape memory comprises a bulbous region configured to abut an edge of the stent and provide protective covering to the edge of the stent. (Item 12) 1. A system for retaining a stent, comprising: a stent delivery system comprising: a first elongate shaft; and a first radially expandable member disposed on a distal portion of the first elongate shaft, the first elongate shaft further comprising a distal radiopaque marker on the distal portion of the first elongate shaft and a proximal radiopaque marker disposed on the distal portion of the first elongate shaft, the proximal marker being proximal to the distal marker; A mold having a cavity, the first radially expandable member is disposed within the cavity and a stent is disposed on the first radially expandable member such that the stent is disposed between the distal radiopaque marker and the proximal radiopaque marker; a mold, the stent comprising a proximal portion and a distal portion, the distal portion of the stent being fully crimped onto the first radially expandable member and the proximal portion not being crimped onto the first radially expandable member such that full crimping prevents axial movement of the stent during delivery; a region of the first radially expandable member comprising a shape memory portion comprising a first bulbous region that abuts the edge of the stent to provide a protective cover to the edge of the stent; A system comprising: (Item 13) Item 13. The system of item 12, wherein the first radially expandable member is a balloon. (Item 14) the first radially expandable member further comprising a proximal portion, a distal portion, and an intermediate portion disposed therebetween; the shape memory portion is applied to the proximal portion without the shape memory portion being applied to the distal portion or the intermediate portion; or the shape memory portion is applied to the distal portion without the shape memory portion being applied to the proximal portion or the intermediate portion; or the shape memory portion is applied to the distal portion and the proximal portion without the shape memory portion being applied to the intermediate portion; Item 13. The system according to item 12. (Item 15) Item 13. The system of item 12, wherein when the shape memory portion is imparted to the proximal portion without the shape memory being imparted to the distal portion or the intermediate portion, or when the shape memory is imparted to the distal portion and the proximal portion without the shape memory being imparted to the intermediate portion, the proximal portion of the first radially expandable member has a diameter greater than the diameter of the distal portion of the first radially expandable member. (Item 16) Item 13. The system of item 12, wherein the distal and proximal portions of the stent are fully crimped onto the first radially expandable member. (Item 17) Item 13. The system of item 12, wherein the shape memory portion is maintained after multiple cycles of expansion and contraction of the first radially expandable member. (Item 18) Item 13. The system of item 12, wherein the stent comprises a sidewall with side holes extending therethrough, the first elongated shaft further comprises a hollow exchange port tube coupled to an outer surface of the first elongated shaft, the hollow exchange port tube having a lumen disposed therethrough, and a second elongated shaft is slidably disposed through the lumen of the hollow exchange port tube such that the second elongated shaft is aligned with the side holes of the stent.

Claims

[Claim 1] Stent retention.

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