Remotely adjustable mechanisms and related systems and methods

Abstract

Aspects of the present disclosure relate to apparatus, systems, and methods including a medical device that includes a remotely actuated cross-sectional adjustment mechanism. The medical device may include a cross-sectional adjustment mechanism configured to actuate an implantable medical device between a first size and a second size greater than the first size to adjust a fluid flow through the implantable medical device.

Description

Technical Field

[0001] The present disclosure relates generally to implantable medical devices, and more particularly to mechanisms for remotely adjusting the cross-section and flow characteristics of implantable medical devices and related systems and methods. Background Art

[0002] Implantable medical devices such as stents, stent grafts, valves, and other intraluminal devices are used in a variety of medical procedures associated with various body passages or cavities to maintain, prevent, and / or regulate fluid flow therethrough. Such devices may be implanted in various locations within a patient's body, including within the vascular system, coronary system, respiratory system, urinary tract, and bile duct, among others.

[0003] In some cases, the necessary size of a medical device may change over time. Current practice often requires replacing the device with a new, differently sized device altogether, which may require further manipulation and / or invasive surgery, thereby causing increased risk, stress, and discomfort to the patient. In other cases, such as during the case of hemodialysis, when the patient is not receiving treatment, the device may be oversized, thereby allowing treatment to be performed at less than optimal performance (e.g., causing too much blood to flow to the patient's heart). Summary of the invention

[0004] In one example ("Example 1"), a medical device including a remotely actuated cross-sectional adjustment mechanism includes: an implantable medical device that defines a cavity; and a cross-sectional adjustment mechanism that is connected to the implantable medical device, the cross-sectional adjustment mechanism being configured to actuate the implantable medical device between a first size and a second size greater than the first size when an external adjustment force is applied to the cross-sectional adjustment mechanism to adjust fluid flow through the cavity.

[0005] In another example ("Example 2"), a medical device configured to be percutaneously adjusted in cross-section (percutaneously perform cross-sectional adjustment) includes: an implantable medical device that defines a cavity; and a cross-sectional adjustment mechanism connected to the implantable medical device, the cross-sectional adjustment mechanism configured to selectively actuate the implantable medical device from a first size to a second size larger than the first size by applying an external adjustment force on the cross-sectional adjustment mechanism along a first radial direction, and to selectively actuate the implantable medical device from the second size to the first size by applying an external adjustment force on the cross-sectional adjustment mechanism along a second radial direction different from the first radial direction.

[0006] According to another example ("Example 3") further relative to the medical device of Example 2, the cross-sectional adjustment mechanism includes a shape memory material configured to move between a first size and a second size in response to an external adjustment force.

[0007] In one example ("Example 4"), a medical device configured to be transcutaneously adjusted in cross-section includes: an implantable medical device that defines a cavity; and a cross-sectional adjustment mechanism connected to the implantable medical device, the cross-sectional adjustment mechanism configured to selectively actuate the implantable medical device between a first dimension toward a second dimension greater than the first dimension by applying heat exceeding body temperature to the cross-sectional adjustment mechanism, and to selectively actuate the implantable medical device from the second dimension to the first dimension when the temperature returns to or is less than body temperature.

[0008] According to another example ("Example 5") that is further than the medical device of Example 4, the cross-sectional adjustment mechanism includes a thermally adjustable material that is configured to maintain a first size when the implantable medical device is at body temperature and to maintain a second size when the implantable medical device is heated to above body temperature.

[0009] In one example ("Example 6"), a medical device including a percutaneously actuatable cross-sectional adjustment mechanism includes: an implantable medical device defining a cavity; and a cross-sectional adjustment mechanism connected to the implantable medical device, the cross-sectional adjustment mechanism being configured to convert to a reduced size when an external adjustment force is applied and to maintain the reduced size when the external adjustment force is removed.

[0010] According to another example ("Example 7") further than the medical device of Example 6, the cross-sectional adjustment mechanism operates to maintain the reduced size via a magnetic force.

[0011] In one example ("Example 8"), a system for controlled blood flow includes: an implantable medical device that defines a cavity; and a cross-sectional adjustment mechanism connected to the implantable medical device, the cross-sectional adjustment mechanism being configured to convert to a reduced size when an external adjustment force is applied and to maintain the reduced size when the external adjustment force is removed; and an external force applicator being configured to apply the external adjustment force to the cross-sectional adjustment mechanism through the patient's skin.

[0012] According to another example ("Example 9") further relative to the system of Example 8, the external force applicator is configured to apply a magnetic force to the cross-section adjustment mechanism.

[0013] According to another example ("Example 10") further to the system of any of Examples 8-9, the cross-sectional adjustment mechanism is configured to reduce thrombosis or stenosis in response to a transition of the implantable medical device between a reduced size and a nominal diameter.

[0014] In one example ("Example 11"), a medical device configured to be actuated through the skin of a patient includes: an implantable medical device defining a cavity and a wall, the wall including an outer surface and an inner surface; and a cross-sectional adjustment mechanism, the cross-sectional adjustment mechanism including a storage portion and a bag between the outer surface and the inner surface of the wall, the storage portion being filled with a fluid, the cross-sectional adjustment mechanism being configured to actuate the implantable medical device between a first size and a second size greater than the first size when an external adjustment force is applied to the storage portion to transfer the fluid from the storage portion to the bag to adjust the fluid flow through the cavity.

[0015] According to another example ("Example 11") further than the medical device of Example 10, the implantable medical device moves from a first size to a second size when fluid is removed from the bag.

[0016] In one example (“Example 12”), a method for adjusting the cross-section of a medical device as described in any of the preceding claims includes: actuating a cross-section adjustment mechanism to move the implantable medical device from a first size to a second size; and actuating the cross-section adjustment mechanism to move the implantable medical device from the second size to the first size.

[0017] According to another example ("Example 13") further than the method of Example 12, the cross-sectional adjustment mechanism is actuated through the patient's skin.

[0018] According to another example ("Example 14") that is further than the method of any one of Examples 12-13, a medical device forms an anastomosis between two blood vessels of a patient, the method further comprising entering the medical device through the patient's skin to enter (reach) the anastomosis when the implantable medical device is in a first size, and actuating the cross-sectional adjustment mechanism to a second size after entering the medical device through the patient's skin to reduce the flow through the implantable medical device.

[0019] According to another example ("Example 15") further than the method of any of Examples 12-14, the method also includes coupling the cross-sectional adjustment mechanism and the implantable medical device, wherein the implantable medical device is one of a new implant or a previously implanted implantable medical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments and together with the description serve to explain the principles of the present disclosure.

[0021] Figure 1 An implantable medical device for controlled blood flow implanted in a patient is shown according to an embodiment;

[0022] Figure 2A is an end view of an implantable medical device including a remotely actuated diameter adjustment mechanism according to an embodiment;

[0023] Figure 2B is a side view of an implantable medical device including a remotely actuated diameter adjustment mechanism according to an embodiment;

[0024] Figure 2C is an end view of an implantable medical device including a remotely actuated diameter adjustment mechanism according to an embodiment;

[0025] Figure 2D is a side view of an implantable medical device including a remotely actuated diameter adjustment mechanism according to an embodiment;

[0026] Figure 3A-3B is a side view of an implantable medical device according to an embodiment;

[0027] Figure 4A is a side view of a medical device including a remotely actuated diameter adjustment mechanism according to an embodiment;

[0028] Figure 4B-4C is an end view of a medical device including a remotely actuated diameter adjustment mechanism according to an embodiment;

[0029] Figure 5A-5B is a side view of a medical device including a remotely actuated diameter adjustment mechanism according to an embodiment. DETAILED DESCRIPTION

[0030] Various aspects of the present disclosure relate to adjustment mechanisms for remotely adjusting the cross-sectional area of ​​an implantable medical device. Examples of implantable medical devices may include stents, stent grafts, valves, and devices for occlusion and / or anastomosis, etc. In some examples, the implantable medical device may be configured to adjust (e.g., increase and / or reduce) the size of a specific artificial body cavity or natural body cavity, passage, and / or conduit to promote, limit, or otherwise adjust the fluid flow therethrough. This diameter or size adjustment may be used as a precursor to treatment, during treatment, or after treatment as desired.

[0031] For reference, the term "cavity" should be broadly understood to include any of a variety of passages, such as those associated with the vascular system, bile duct, urinary tract, lymphatic system, reproductive system, gastrointestinal system or other. Also, the terms "cross-sectional area", "diameter" or "diametric (radial)" should not be understood to require a circular cross-section. Instead, these terms should be understood to represent an effective cross-sectional area or diameter, or in some cases the maximum transverse dimension of a cross section. Therefore, unless otherwise indicated, the terms "cross-sectional area", "diameter" or "diametric" can be understood to mean a more general "size".

[0032] In some cases, it may be beneficial to temporarily adjust the diameter or cross-sectional area of ​​an implantable medical device after implantation in a patient. For example, in certain medical procedures (e.g., in the case of hemodialysis), a higher blood flow through the device may be required or desired while the procedure is being performed. However, it may be beneficial to reduce the blood flow through the device after the procedure so as not to provide blood overflow to the patient's heart.

[0033] In the above examples, it may also be beneficial to be able to adjust the implantable medical device without additional invasive procedures. Invasive procedures such as these can cause additional stress and discomfort to the patient. In addition, non-invasive procedures are generally less burdensome to the healthcare provider in terms of preparation, treatment, and follow-up efforts. In summary, various embodiments propose solutions for achieving health benefits with potential reduction in additional burden on patients and / or medical providers.

[0034] Figure 1 An implantable medical device 100 for controlling blood flow (volume) implanted in a patient's body B is shown according to one embodiment. Figure 1 In an embodiment, the patient already has an AV fistula, which is a connection between an artery and a vein, and Figure 1 Shown is placed in the patient's forearm.While an AV fistula is used as the primary example, it should be understood that any of a variety of body cavities and tracts may be considered in connection with the inventive concepts described herein.

[0035] The medical device 100 has been placed in an AV fistula and includes a conduit 110 and an adjustment mechanism 120 coupled to the conduit 110. In various examples, the conduit 110 defines an inner flow lumen and is configured to convey a body fluid (e.g., blood) as desired. Although various forms of the conduit 110 are contemplated, some examples include a graft, a stent graft, a heart valve, a vascular filter, or other implantable medical device. Advantageous conduit forms may include a graft, a stent graft, a heart valve, a vascular filter, or other implantable device conduit utilizing expanded polytetrafluoroethylene (ePTFE) technology, such as those products available from WL Gore and Associates, Inc. Any of a variety of additional and alternative materials are contemplated, and the ePTFE example should not be construed in a limiting sense.

[0036] The adjustment mechanism (e.g., diameter adjustment mechanism) 120 is configured to be actuated between a first size and a second size (e.g., which may be a preset cross-sectional area(s) or diameter(s)) through the patient's skin via application of an external adjustment mechanism (e.g., a physical force, an energy force, an ultrasonic force, a thermal force, or a combination thereof) without piercing the patient's skin (e.g., without creating a wound or other percutaneous access). The adjustment mechanism 120, in turn, can adjust the flow area of ​​the conduit 110, and thus adjust the device 100 between various diameters or cross-sectional areas. In this manner, the size or size of the lumen of the device 100, and thus the flow rate through the device 100, can be externally adjusted (e.g., via application of an external adjustment force), thereby reducing or eliminating the need for an invasive procedure (surgery) to replace the device 100 with another device having a different flow cross-sectional area, or reducing or eliminating the need to otherwise modify the flow cross-sectional area of ​​the device 100 through invasive techniques.

[0037] As described above, in some cases, the device 100 forms an anastomosis between two blood vessels of a patient. The device 100 can be touched through the patient's skin to regulate or change the flow through the anastomosis. For example, the adjustment mechanism 120 can be actuated to convert the device 100 from the first cross-sectional area A1 to the second cross-sectional area A2 so that the flow rate can be changed (e.g., the flow rate through the device 100 increases). In some examples, the adjustment mechanism 120 can then be actuated back to the first cross-sectional area A1 (e.g., to reduce the flow rate through the device 100). In other examples, the adjustment mechanism 120 is self-actuated or self-deployed, and returns to the first cross-sectional area A1 without intervention by the user (e.g., after a period of time).

[0038] Figures 2A to 2D2 is an end view and a side view of an implantable medical device 200 including a conduit 210 having an inner flow lumen 230 and a diameter adjustment mechanism 220 according to one embodiment. The implantable medical device 200 may optionally be used as or for Figure 1 The device 200 is a portion of an implantable medical device 100 (e.g., as an anastomosis between two blood vessels) and incorporates any features associated with the previously described medical device 100. As shown, the diameter adjustment mechanism 220 is coupled to the conduit 210. In some cases, the diameter adjustment mechanism 220 is generally disposed around a portion of the outer surface of the conduit 210, such that a change in the diameter of the diameter adjustment mechanism 220 also changes the cross-sectional area of ​​the inner flow lumen 230 of the conduit 210, and thus the inner flow lumen of the device 200.

[0039] In one example, the diameter adjustment mechanism 220 is configured to selectively actuate the inner flow cavity of the conduit 210, and more generally the device 200, between a first cross-sectional area A1 and a second cross-sectional area A2. For example, in some cases, depending on the desired flow dynamics through the cavity 230, the first cross-sectional area A1 can be about 2 mm to about 4 mm, while the second cross-sectional area A2 can be about 6 mm to about 8 mm. Adjusting the device 200 between the first cross-sectional area A1 and the second cross-sectional area A2 adjusts the amount of fluid flowing through the cavity 230, for example, from a smaller flow rate to a larger flow rate, or vice versa. In other examples, there can be actuation between at least two different sizes.

[0040] As desired, the cross-sectional adjustment mechanism 220 may be disposed on any portion of the conduit 210. Typically, the length of the cross-sectional adjustment mechanism 220 is less than the total length of the device 200. For example, as desired, the length of the cross-sectional adjustment mechanism 220 may be 80-90% of the length of the device 200, 70-80% of the length of the device 200, 50-70% of the length of the device 200, or less than 50% of the length of the device 200. For example, in some cases, the cross-sectional adjustment mechanism 220 may simply include a ring or hoop-like structure coupled to the outer surface of the conduit 210. In other examples, the cross-sectional adjustment mechanism 220 may be a stent-like structure covering a portion of the conduit 210 or disposed within the lumen 230 of the conduit 210. In some examples, the adjustment mechanism may be along the inner surface of the conduit 210.

[0041] exist Figures 2A to 2D In the example of FIG. 2 , the inner flow cavity 230 of the device 200 is adjusted between the first cross-sectional area A1 and the second cross-sectional area A2 by applying an external adjustment force to the cross-sectional adjustment mechanism 220 . For reference, Figure 2A and 2C is a transverse cross-section of the device 200 at the cross-section adjustment mechanism 220 . Figure 2A and 2BThe medical device 200 is shown transitioning to a second larger cross-sectional area A2, and Figure 2C and 2D The device is shown transitioning to a first smaller cross-sectional area A1.

[0042] The external adjustment force may be a physical radial force (eg, clamping) of the medical device 200, and specifically of the cross-sectional adjustment mechanism 220. Specifically, the cross-sectional adjustment mechanism 220 is configured such that the cross-sectional adjustment mechanism 220 is radially radially radially directed along the first direction F1 ( Figure 2C and 2D ) causes the cross-sectional adjustment mechanism to expand (outward) or flip outward, and in the second direction F2 ( Figure 2A and 2B ) causes the cross-sectional adjustment mechanism 220 to flip reversibly (inwardly) or collapse inwardly to Figure 2C and 2D The collapsed or "clamped" configuration is maintained due to the elasticity of the material, and vice versa.

[0043] In this clamped or deflected position, the medical device 210 defines a first (smaller) cross-sectional area A1 with a smaller internal flow lumen 230. The adjustment mechanism 220 can be reversibly expanded by applying a physical radial force (e.g., clamping) the adjustment mechanism 220 in a second direction (e.g., perpendicular to the first direction) to cause the cross-sectional adjustment mechanism to expand such that the medical device defines a second (larger) cross-sectional area A2 with a larger flow lumen 230.

[0044] For example, the cross-sectional adjustment mechanism 220 may be configured to move from the first cross-sectional area A1 to the second cross-sectional area A2 in response to an external adjustment force applied along the first radial direction F1, and may be configured to move from the second cross-sectional area A2 back to the first cross-sectional area A1 in response to an external adjustment force applied along a second radial direction F2 different from the first radial direction F1.

[0045] In some cases, the cross-sectional adjustment mechanism 220 may include an elastic or superelastic material (e.g., a shape memory alloy) configured to transition between the first cross-sectional area A1 and the second cross-sectional area A2 when an external adjustment force is applied to the diameter adjustment mechanism 220. In various examples, the cross-sectional adjustment mechanism 220 inverts (everts) or flips along an orientation between two diameter conditions or between the cross-sectional areas A1 and A2.

[0046] Figure 3A and 3B3 is a side view of an implantable medical device 300 including a conduit 310 and a diameter adjustment mechanism 320 according to an embodiment. As shown, the diameter adjustment mechanism 320 of the device 300 is coupled to the conduit 310. In some cases, the cross-sectional adjustment mechanism 320 is generally disposed around a portion of the outer surface of the conduit 310, such that a change in the cross-sectional area of ​​the cross-sectional adjustment mechanism 320 also changes the cross-sectional area of ​​the inner flow lumen 330 of the conduit 310, and thus the inner flow lumen of the device 300.

[0047] The cross-sectional adjustment mechanism 320 is configured to selectively actuate the inner flow chamber 330 of the device 300 between a first cross-sectional area A1 and a second cross-sectional area A2 that is greater than the first cross-sectional area A1. For example, in some cases, the first cross-sectional area A1 may be about 2 mm to about 4 mm, while the second cross-sectional area A2 may be about 6 mm to about 8 mm, depending on the desired flow dynamics (flow dynamics) through the inner flow chamber 330. Adjusting the cross-sectional adjustment mechanism 320, and thus the inner flow chamber 330, between the first cross-sectional area A1 and the second cross-sectional area A2 adjusts the amount of fluid flowing through the inner flow chamber 330, for example, from a smaller flow rate to a larger flow rate and from a larger flow rate to a smaller flow rate.

[0048] The cross-sectional adjustment mechanism 320 may be disposed on any portion of the conduit 310. In some cases, the diameter adjustment mechanism 320 may be approximately the same length as the overall length of the device 300, while in other cases, the length of the diameter adjustment mechanism 320 may be less than the overall length of the device 300. For example, the length of the diameter adjustment mechanism 320 may be 80-90% of the length of the device 300, 70-80% of the length of the device 300, 50-70% of the length of the device 300, or less than 50% of the length of the device 300, as desired. For example, in some cases, the cross-sectional adjustment mechanism 320 may simply include a ring or hoop-like structure coupled to the outer surface of the device 300. In other examples, the cross-sectional adjustment mechanism 320 may be a stent-like structure that covers a portion of the device 300.

[0049] The device 300 is adjusted between the first cross-sectional area A1 and the second cross-sectional area A2 by applying an external adjustment force to the cross-sectional adjustment mechanism 320. The external adjustment force can be any force of various types. In some cases, the cross-sectional adjustment mechanism 320 may include a thermally adjustable or heat-adjustable material that is configured to maintain the first cross-sectional area A1 when the device 300 is at body temperature and maintain the second cross-sectional area A2 when the device 300 is heated above body temperature. For example, the cross-sectional adjustment mechanism 320 is optionally formed of a shape memory material such as a nickel-titanium alloy that is configured to change phase above body temperature.

[0050] In some examples, upon application of an external heat source (e.g., a heat lamp not shown), the shape memory material changes phase and causes the cross-sectional adjustment mechanism 300, and therefore the conduit 310 and the inner flow cavity 330 of the device 300, to transition from the first cross-sectional area A1 to the second cross-sectional area A2. Upon removal of the external heat source, the inner flow cavity of the device 300 returns from the second cross-sectional area A2 to the first cross-sectional area A1.

[0051] In other examples, thermal energy is applied to the device in the form of cooling (e.g., an ice pack), which causes the shape memory material to change phase and causes the inner flow lumen 330 of the device 300 to transform from the first cross-sectional area A1 to the second cross-sectional area A2. After the thermal energy (e.g., the ice pack) is removed, the patient's body warms up, which causes the diameter adjustment mechanism 320, and therefore the inner flow lumen 330 of the conduit 310 and the device 300, to transform from the second cross-sectional area A2 to the first cross-sectional area A1.

[0052] Examples of suitable thermally regulatable materials include any of a variety of shape memory materials, primarily including nickel-titanium alloy shape memory materials (eg, Nitinol), including polymer shape memory or phase change materials.

[0053] Figure 4A is a side view of an implantable medical device 400 including a conduit 410 and a cross-sectional adjustment mechanism 420 according to one embodiment. Figure 4B and 4C According to one embodiment, the cross-sectional adjustment mechanism 420 is included. Figure 4A An end view of an implantable medical device 400 is shown. Figure 4A As shown, the cross-section adjustment mechanism 420 is coupled to the conduit 410. In general, the cross-section adjustment mechanism 420 may be coupled to the conduit 410 at any location along the conduit 410 (eg, from the first end 402 to the second end 404 of the apparatus 400).

[0054] The cross-sectional adjustment mechanism 420 is configured to selectively actuate the device 400 between a first cross-sectional area A1 and a second cross-sectional area A2 that is larger than the first cross-sectional area A1. Figure 4B and 4C As shown, the inner flow cavity 400 of the conduit 410 is adjusted between a first cross-sectional area A1 and a second cross-sectional area A2. For example, in some cases, the first cross-sectional area A1 can be about 2 mm to about 4 mm, and the second cross-sectional area A2 can be about 6 mm to about 8 mm, depending on the desired flow dynamics (flow dynamics) through the cavity 410. Adjusting the device 400, and specifically adjusting the inner flow cavity 430, between the first cross-sectional area A1 and the second cross-sectional area A2 adjusts the amount of fluid flowing through the inner flow cavity 430, for example, from a smaller flow rate to a larger flow rate, and from a larger flow rate to a smaller flow rate.

[0055] like Figure 4B and 4C As shown, in some cases, the cross-sectional adjustment mechanism 420 may include a first adjustment portion 422 and a second adjustment portion 424, which are arranged at a distance from each other along the periphery of the pipe 410. The first adjustment portion 422 and the second adjustment portion 424 are generally configured to match each other to clamp the device 400 and maintain the inner flow cavity 430 of the pipe 410, and more generally (the inner flow cavity 430 of the device 400) at the first cross-section A1. The first adjustment portion 422 and the second adjustment portion 424 are configured to separate from each other and move the inner flow cavity 430 to the second cross-section A2 when an external adjustment force is applied. For example, in some cases, the cross-sectional adjustment mechanism 420 may include magnets that are configured to interact with each other to maintain the inner flow cavity 430 of the device 400 at the first cross-section A1, and are configured to separate from each other when a magnetic force is applied to drive the device 400, thereby converting the inner flow cavity 430 to the second cross-section A2, and vice versa.

[0056] In some cases, an external adjustment force can be applied with an external force applicator (not shown). For example, the external force applicator can be a magnet strong enough to overcome the attraction between the first adjustment portion 422 and the second adjustment portion 424 to separate the first adjustment portion 422 and the second adjustment portion 424 from each other.

[0057] Figure 5A and 5B 5 is a side view of an implantable medical device 500 including a conduit 510 and a cross-sectional adjustment mechanism 520 according to an embodiment. As shown, the conduit 510, and therefore the device 500, defines an inner flow cavity 530 and includes a wall having an inner surface 532 and an outer surface 534. The cross-sectional adjustment mechanism 520 includes a bag 540 located between the inner surface 532 and the outer surface 534 of the wall. The bag 540 is fluidly connected to a reservoir 550 configured to hold a fluid (e.g., water, saline, or any other suitable fluid). When an external adjustment force is applied to the cross-sectional adjustment mechanism 520, the fluid can move from the reservoir 550 to the bag 540 to maintain the cross-section of the inner flow cavity 530 at a first cross-section A1, and return from the bag 540 to the reservoir 550 to maintain the inner flow tube 530 of the device 500 at a second cross-section A2.

[0058] The cross-sectional adjustment mechanism 520 is configured to selectively actuate the inner flow chamber 530 of the device 500 between a first cross-sectional area A1 and a second cross-sectional area A2 that is greater than the first cross-sectional area A1. For example, in some cases, the first cross-sectional area A1 may be about 2 mm to about 4 mm, while the second cross-sectional area A2 may be about 6 mm to about 8 mm, depending on the desired flow dynamics (flow dynamics) through the chamber. Adjusting the device 500 between the first cross-sectional area A1 and the second cross-sectional area A2 adjusts the amount of fluid flowing through the inner flow chamber 530, for example, from a smaller flow rate to a larger flow rate, and vice versa.

[0059] Typically, the fluid is maintained in the bag 540 until an external adjustment force is applied to the bag 540. In some cases, the external adjustment force is a force applied through the patient's skin by a physician or other operator (e.g., squeezing or clamping a portion of the cross-sectional adjustment mechanism 520). For example, the external adjustment force is applied to the bag 540 to force the fluid to flow from the bag 540 into the reservoir 550 and actuate the inner flow chamber 530 and more generally the device 500 from the first cross-sectional area A1 to the second cross-sectional area A2. Similarly, the external adjustment force can be applied to the reservoir 550 to force the fluid back into the bag 540 to actuate the inner flow chamber 530 and more generally the device 500 from the second cross-sectional area A2 back to the first cross-sectional area A1.

[0060] In some cases, the fluid can be a high viscosity substance, such as a biocompatible polymer, or a shear-thinning fluid, or a gel material. Shear-thinning materials such as hydrogels can be used. In this case, the applied local force will cause the viscous fluid to thin and flow. When the force causing the shear stops, the material quickly returns to its viscous gel-like state until another force is applied. Magnetic fluids or "ferrous fluids" are also considered. These materials change shape in the presence of a magnetic field. In these cases, the external regulating force may also include heat applied through the patient's skin. Heat can reduce the viscosity of the fluid so that the fluid flows between the bag 540 and the reservoir 550. Once the heat is removed, the viscosity of the fluid increases, thereby maintaining the fluid in the bag 540 or the reservoir 550 and then maintaining the device 500, more specifically the inner flow cavity 530, at the first cross-section A1 or the second cross-section A2, respectively.

[0061] The cross-sectional area A1 can be equal to zero. The actuation of the device discussed herein, such as the actuation of the device 200, 300, 400, 500, can be between fully open (A2) and fully closed (A1). Therefore, when the device 200, 300, 400, 500 is fully closed, the blood will not flow. In order to prevent the blood from clotting in these cases, a "locking solution" can be injected through one of the dialysis access needles. The locking solution or heparin lock is used as an anticoagulant in the double chamber of the central venous catheter used in dialysis. The same solution can be used to prevent clotting in the closed fistula until the next dialysis course triggers a cross-sectional change and the dialysis process begins again. In addition, the actuation of the device 200, 300, 400, 500 and more specifically the actuation of the cross-sectional adjustment mechanism can reduce the possibility of thrombosis or stenosis based on the conversion of the implantable medical device 200, 300, 400, 500 between the reduced size and the nominal diameter. If the conversion is performed on a daily or weekly basis, the adjustment can reduce the possibility of blood stagnation in certain circumstances.

[0062] Devices 200, 300, 400, 500 can be separate devices added to a prosthetic graft or a natural fistula, or devices 200, 300, 400, 500 can be manufactured as part of an integral component of a graft. A cross-sectional adjustment mechanism (e.g., a remotely adjustable mechanism) can be added to a new graft, or a cross-sectional adjustment mechanism can be added after the graft has been implanted or a fistula has been created. Implantation can be surgically implanted, or in some embodiments, intravascularly implanted. In some cases, the remotely adjustable mechanism can be placed in the cavity of the device, while in other cases, the remotely adjustable mechanism is designed to be placed in the abdominal cavity. It is conceivable that a combination of these devices can be used together. For example, it may be desirable to close the AV access graft at both ends and heparin lock the segment between the remotely adjustable mechanisms.

[0063] Various methods of implanting the aforementioned devices 200, 300, 400, 500 include implanting each device into a percutaneously accessible site without major trauma (e.g., a needle stick) to actuate an associated cross-sectional adjustment device to change the size of the internal flow cavity of the device. Those skilled in the art will readily appreciate that various aspects of the present disclosure may be implemented by any number of methods and devices configured to perform the intended functions. It should also be noted that the drawings referenced herein are not necessarily drawn to scale, but may be exaggerated to illustrate various aspects of the present disclosure, and in this regard, the drawings should not be construed as limiting.

Claims

1. A medical device configured to be adjusted transcutaneously in cross section, the device comprising: an implantable medical device, the implantable medical device defining a cavity; as well as A cross-sectional adjustment mechanism is connected to the implantable medical device, the cross-sectional adjustment mechanism being configured to selectively actuate the implantable medical device from a first size including a first cross-sectional area of ​​the cavity to a second size including a second cross-sectional area of ​​the cavity that is larger than the first size by applying a first external adjustment force along a first radial direction on a first portion of the cross-sectional adjustment mechanism, and to selectively actuate the implantable medical device from the second size to the first size by applying a second external adjustment force along a second radial direction that is perpendicular to and different from the first radial direction on a second portion of the cross-sectional adjustment mechanism that is perpendicular to the first portion.

2. The medical device according to claim 1, characterized in that The cross-sectional adjustment mechanism includes a shape memory material configured to move between the first dimension and the second dimension in response to the external adjustment force.

3. The medical device according to claim 1, characterized in that An external adjustment force in the first radial direction causes the cross-section adjustment mechanism to flip outward.

4. The medical device according to claim 1, characterized in that An external adjustment force in the second radial direction causes the cross-section adjustment mechanism to turn inward.

5. The medical device according to claim 1, characterized in that The cross-section adjustment mechanism is positioned along an inner surface of the cavity.

6. The medical device according to claim 1, characterized in that The first external adjustment force and the second external adjustment force are applied by a doctor or an operator.

7. The medical device according to claim 1, characterized in that The first external adjustment force and the second external adjustment force are one of a pressing force and a clamping force.

Images