A multi-release covered stent and covered stent system thereof

Abstract

The present invention provides a multiple-release covered stent, which includes a stent body and a fixing portion, wherein the stent body includes a metal stent and a covering, the metal stent supports the covering to form the covered stent, and the fixing portion is used to tighten and fix the contracted state of the covered stent, enter the blood vessel during surgery, and the fixing portion also controls the multiple deployments of the covered stent after the covered stent reaches the treatment position. Compared with the existing technology, the present invention is the first to achieve a covered stent and its system that can be more accurately positioned during interventional surgery without being affected by blood flow impact, and can ensure blood flow during surgery, reduce the technical requirements for doctors themselves, structurally ensure the order of multiple releases, and further achieve accurate positioning of the covered stent to complete intervention, making various intravascular reconstruction and other treatments safe, stable, and easy.

Description

Technical Field

[0001] The present invention relates to a multi-release covered stent and a covered stent system thereof in interventional surgery, and belongs to the field of interventional medical devices. Background Art

[0002] With the aging population and the increasing prevalence of hypertension and arteriosclerosis, the number of patients with cerebral vascular diseases and aortic diseases is increasing year by year. Open surgery is still the primary treatment for these patients. However, open surgery is highly traumatic, requires extracorporeal circulation, and is time-consuming. Longer surgeries are associated with higher rates of postoperative complications and mortality. Minimally invasive treatments for various vascular diseases are the goal of aortic disease treatment, following the achievement of minimally invasive treatment for simple lesions.

[0003] Taking aortic disease as an example, prolonged occlusion of the brain's blood supply is crucial. Ischemia exceeding ten minutes can lead to severe, irreversible brain damage due to hypoxia. The diverse structures of various blood vessels, such as the aortic arch, are particularly complex. Not only do three major branches of blood vessels supplying the brain and upper limbs originate from the aortic arch, but the arch itself also exhibits frequent variations in its three-dimensional morphology. Furthermore, aortic diseases such as aneurysms, penetrating ulcers, and aortic dissections can affect the arch. Advances in endovascular technology and increasing surgeon experience have led to the development of "hybrid" procedures that combine endovascular techniques with surgical interventions for aortic arch lesions. Other endovascular repair techniques, such as branched stenting, chimney stenting, and fenestrated stenting, have also been developed. However, these procedures are prone to endoleaks, are complex, involve significant trauma, and can easily overwhelm branches above the arch, resulting in serious complications. Similarly, endovascular covered stent grafts are difficult to routinely treat for lesions of the abdominal aorta involving branch vessels. While fenestrated, chimney, and periscope stent grafts are currently available, they are complex to perform, require customization, and offer uncertain long-term efficacy. Currently, there is no ideal, simple, and safe method for treating vascular lesions in the brain, aortic arch, or abdominal aortic branches. Lesions in these areas have always been challenging to treat, limiting the use of minimally invasive endovascular therapies for these conditions. These factors make multi-branch designs difficult to meet most clinical needs, and they are also difficult to perform and have a high incidence of surgical complications.

[0004] Before deployment, the stent graft must be loaded into the delivery system. The stent graft is then slowly unfolded using a release sheath, a process known as a primary release. After the primary release, the bare stent at the end of the stent graft is locked, meaning it is not deployed. Finally, the bare stent portion of the stent graft is released through a secondary release, achieving full deployment of the stent graft. The delivery system is then safely withdrawn from the patient's body, ensuring minimal damage to the blood vessel. If the stent graft is deployed incorrectly within the patient's body, it will lose its precise positioning, leading to complete surgical failure and, in severe cases, life-threatening consequences. Currently, stent grafts and their delivery systems cannot be repositioned within the vessel after deployment. Furthermore, they can be displaced by blood flow impact during the secondary release. Furthermore, the extent of the impact of the primary and secondary releases on the vessel is difficult to quantify, placing high demands on the surgeon's skills, resulting in increased surgical difficulty and a low success rate. In particular, inaccurate stent positioning due to blood flow impact can result in ineffective treatment of the lesion, leading to the risk of a secondary surgery. Furthermore, areas that should not be covered may become covered, necessitating additional measures to rescue the patient.

[0005] Therefore, surgeons expect a multi-release covered stent and covered stent system that can ensure blood flow and precise positioning, as well as an integrated covered stent that can achieve precise positioning to complete intervention, making various complex intravascular reconstruction and other treatments safe, stable and easy. Summary of the Invention

[0006] In response to the problems existing in the existing technology, the purpose of the present invention is to provide a multi-release covered stent to avoid serious accidents caused by high surgical difficulty or errors, ensure blood flow in blood vessels during surgery, and accurately locate the lesion site, so as to achieve blood supply guarantee and more accurate positioning in multiple scenarios.

[0007] Based on the above-mentioned purpose, the present invention provides a multiple-release coated stent, which includes a stent body and a fixing part, wherein the stent body includes a metal stent and a coating, the metal stent supports the coating to form a coated stent, and the fixing part is used to tighten and fix the contracted state of the coated stent, so that it can enter the blood vessel in a very small size during surgery, and the fixing part also controls the multiple expansion of the coated stent after the coated stent reaches the treatment position.

[0008] Preferably, the fastening portion includes a first fastening member and a second fastening member, and the first fastening member and the second fastening member are released one by one in sequence, and when the first fastening member is released, the second fastening member still constrains the coated bracket to be in a non-fully expanded state.

[0009] More preferably, the first fastener and the second fastener are fastened and contracted by different core wires to fasten the coated stent, and the maximum lengths of the fastening arm of the first fastener and the fastening arm of the second fastener are different. In other words, when the first core wire of the first fastener is pulled out, the fixing arm of the first fastener loses its restraining force and therefore stretches. At this time, the coated stent is expanded to the fastened and contracted state of the second fastener, and the coated stent is in a non-fully expanded state. The first fastener preferably fastens the coated stent into an axially tightened state, so that the coated stent is loaded in the delivery system so that it can be delivered into the blood vessel.

[0010] As a preferred embodiment, the second fastener can constrain the stent graft to 40% to 70% of its designed diameter. Similarly, when the second core wire of the second fastener is withdrawn, the second fastener loses its constraint on the stent graft and expands its arms. At this point, the stent graft is fully deployed to the same diameter as the vessel at the adaptive treatment site, and the stent graft fully expands on its own, reaching 100% of its designed diameter. To facilitate differentiation between the two fasteners, the fastening arms can be configured with different diameters, such as having a larger diameter than the first fastener.

[0011] More preferably, the first and second fastening members are each provided with a plurality of fastening clips, each having a pair of fastening arms, one end of each pair of fastening arms being fixed to the stent graft body by hinged connection or suture, and the other end of each pair of fastening arms being provided with a fastening hole, which is then aligned with each other and fastened with a core wire. In other words, each pair of fastening arms is fastened to form a loop, thereby constricting the stent graft into a contracted state.

[0012] More preferably, the securing arms of the first and second securing members can be simplified to a single arm, and multiple single securing arms can be provided. Any non-endpoint portion of the single securing arm, such as the middle section, can be secured to the stent graft body. The single securing arms are provided with securing holes at both ends. After the securing holes at both ends overlap, the single securing arms are fastened and secured via a core wire, thereby tightening the stent graft. Both the first and second securing members can employ this single-arm approach to contract and secure the stent graft.

[0013] The second object of the present invention is to provide a coated stent system, which includes the above-mentioned coated stent and a delivery system for use. The delivery system includes a conical head, a marker, a core wire, a pull wire handle, a fixer, a core shaft tube, a support tube, a handheld part, a tail end connector and a loader.

[0014] Preferably, for the stent graft delivery system with direction selection, a mark is provided on the conical head, and the mark is preferably a developing mark, for example, which can be developed under X-ray images.

[0015] Further preferably, the mark consists of an axial mark and a radial mark, the axial mark is parallel to the core shaft tube, and the radial mark is perpendicular to the plane formed by the axial mark and the core shaft tube. As a preferred embodiment, the development shape of the axial mark can be a long strip, parallel to the whole. The shape of the radial mark can be circular, parallel to the core wire. When the opening of the embedded stent portion is projected directly onto the greater curvature side of the aortic arch, the development shape of the axial mark can be a strip, parallel to the guide wire, and basically blocked by the guide wire. The shape of the radial mark can be a rectangle perpendicular to the plane where the guide wire is located. As a preferred embodiment, a hardened guide wire is selected for the guide wire.

[0016] More preferably, the core wire is composed of two core wires, which are divided into a first core wire and a second core wire, wherein the core wire that is tied to the first fastener is the first core wire, and the core wire that is tied to the second fastener is the second core wire; a pull wire handle connecting the core wires is provided at the end of the delivery system, and the pull wire handles connecting the first core wire and the second core wire are named the first pull wire handle and the second pull wire handle. It is worth mentioning that the present invention cleverly fixes the first pull wire handle and the second pull wire handle at the handheld portion, and through the cooperation of the first pull wire handle and the second pull wire handle, the pulling order of the first pull wire handle and the second pull wire handle must be that the first pull wire handle is pulled out before the second pull wire handle can be pulled out, which can effectively avoid the failure of the semi-release function of the first deployment due to the wrong operation sequence.

[0017] Further preferably, the first pull-wire handle is provided with a card slot, the second pull-wire handle is provided with a protruding connecting piece, and the length of the first pull-wire handle is longer than that of the second pull-wire handle, so as to facilitate the priority operation of the first handle; the hand-holding part is provided with two slots, each slot is suitable for a pull-wire handle to pass through; when in use, the first pull-wire handle and the second pull-wire handle are inserted into the hand-holding part through the slot and then the second pull-wire handle is rotated to make the connecting piece snap into the card slot.

[0018] Further preferably, in another embodiment of the pull-wire handle, the length of the first pull-wire handle is longer than that of the second pull-wire handle, the second pull-wire handle is provided with a protrusion, the hand-holding portion is provided with a sleeve for inserting the first pull-wire handle and the second pull-wire handle, and the sleeve is provided with a groove that cooperates with the protrusion; when in use, the protrusion is inserted into the groove to limit the first pull-wire handle and the second pull-wire handle.

[0019] More preferably, the fixator is composed of a fixing ring and a fixing core wire, the fixing ring is a double-hole structure, the large hole is sleeved on the core shaft tube, and the end of the fixing core wire is inserted into the small hole. A clothes fork structure (h-shaped) is formed on the core shaft tube by the fixator.

[0020] More preferably, the core shaft tube runs through the entire delivery system from the inside of the tapered head to the tail connector at the end, serving as a channel for tracking the guide wire and connecting the entire delivery system.

[0021] More preferably, the support tube sleeve is arranged behind the core shaft tube bracket section to the inside of the handheld part, and is composed of a three-lumen tube and a thickened layer, and the thickened layer is a reinforced steel tube.

[0022] More preferably, the three-lumen tube has three lumens, forming three passages throughout the entire support tube. The core shaft lumen is located in the innermost layer of the support tube and is coaxially connected to the outer wall of the core shaft tube. The other two lumens serve as passages for the core wires, namely the first core wire lumen and the second core wire lumen. As a preferred embodiment, the portion of the three-lumen tube located outside the body is sheathed with metal tubing to increase strength, such as stainless steel tubing as a reinforcing steel tube, to enhance the operability of the delivery system.

[0023] Further preferably, a thickened layer is provided on the outer wall of the three-lumen tube to make the three-lumen tube transition smoothly, so that the delivery system can smoothly enter the adjustable sheath or the adjustable valve sheath can be withdrawn.

[0024] More preferably, a hand-grip portion is provided at the rear end of the support tube, and the hand-grip portion is used to facilitate grasping and fixing the first wire-pulling handle and the second wire-pulling handle during operation.

[0025] More preferably, the loader is used to flush and exhaust the membrane and allow the coated stent to smoothly pass through the hemostatic valve of the adjustable valve sheath. The loader includes a tube body, a side tube, a valve, a seat, and a hemostatic valve.

[0026] Further preferably, the proximal end of the stent graft is fixed by a fixator, so as to facilitate the delivery system to push the stent graft within the sheath and to precisely position the stent graft at the lesion (to avoid the stent graft from moving backward relative to the delivery system when pushing and retracting the core wire). As a preferred embodiment, the fixed core wire on the fixator ties the coil on the inner side of the front end of the stent body, thereby fixing the proximal end of the above-mentioned adaptive transthoracic aortic stent graft. In this way, under the condition that the front end of the stent is constrained by the fixator, the stent graft can maintain an unchanged axial position with the delivery system during delivery, initial release, and full deployment, thereby ensuring the precise release of the stent graft.

[0027] It is worth mentioning that the above-mentioned coated stent can also be transported in the sheath in conjunction with the delivery system. At this time, the coated stent system is released three times. The first release is to release the coated stent from the delivery sheath. At this time, the coated stent is still in a tightened state. The second release is to release the first fastener to make the coated stent partially expanded. At this time, the blood flow in the blood vessel can be shunted through the inside and outside of the stent respectively, greatly reducing the impact of blood flow. Moreover, since the coated stent is not attached to the blood vessel wall after the first release, the fixator also fixes the proximal end of the coated stent. Under this condition, the release position can be further adjusted, so that the coated stent can be easily positioned in the axial and circumferential directions through the delivery system; the third release is to make the coated stent fully expanded after precise positioning. At this time, subsequent intraoperative operations can be performed to treat the lesion.

[0028] the term

[0029] Interventional surgery: It is a minimally invasive treatment performed using modern high-tech means. Under the guidance of medical imaging equipment, special catheters, guide wires and other precision instruments are introduced into the human body to diagnose and treat internal diseases.

[0030] Extracorporeal circulation: The purpose of extracorporeal circulation is to maintain blood supply throughout the body during open-heart surgery. This is a life-support technique that uses a series of specialized artificial devices to drain blood from the veins back into the body, artificially exchange gases, regulate temperature, and filter blood before returning it to the arterial system. Extracorporeal circulation, also known as extracorporeal circulation, involves artificial devices replacing human functions.

[0031] Stent graft: A stent graft is a membrane-based stent supported by a metal stent. Typically, a stent made of a special membrane material (such as polytetrafluoroethylene, Dacron, polyester, or polyurethane) is fused or sutured onto the metal stent. This retains the functionality of the metal stent while retaining the insulating properties of the membrane material.

[0032] Compared with the existing technology, the present invention is the first to realize a covered stent and its system that can be more accurately positioned during interventional surgery without being affected by blood flow impact, and can ensure blood flow during the operation, reducing the technical requirements for the doctor himself, and structurally ensuring the sequential order of multiple releases. In addition, it can achieve precise positioning of the covered stent to complete the intervention, making various intracavitary reconstruction and other treatments safe, stable and easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the three-dimensional structure of the stent graft in Example 1 of the present invention;

[0034] FIG2( a ) is a schematic diagram of the stent graft in Example 1 of the present invention when being tightened;

[0035] FIG2( b ) is a schematic diagram of a single fastening clip of the stent graft in Example 1 of the present invention;

[0036] Figure 3 Schematic diagram of the structure of the conveying system in Example 1 of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure of the conical head in Example 1 of the present invention;

[0038] Figure 5 Schematic diagram of the application structure of the core wire in Example 1 of the present invention;

[0039] Figure 6 This is a schematic diagram of the connection position of the pull wire handle in Example 1 of the present invention;

[0040] Figure 7 Schematic diagram of the cross-sectional structure of the wire pull handle in Example 1 of the present invention;

[0041] Figure 8 This is a structural diagram of another embodiment of the first pull-wire handle in Example 1 of the present invention;

[0042] Figure 9 This is a structural diagram of another embodiment of the second pull-wire handle in Example 1 of the present invention;

[0043] Figure 10 This is a schematic diagram of the operation of another embodiment of the pull-wire handle in Example 1 of the present invention;

[0044] Figure 11 This is a partial structural diagram of the handheld housing in Example 1 of the present invention;

[0045] Figure 12 This is a schematic structural diagram of the first pull-wire handle in Example 1 of the present invention;

[0046] Figure 13 This is a schematic structural diagram of the second pull-wire handle in Example 1 of the present invention;

[0047] Figure 14 This is a schematic diagram of the pull-wire handle in Example 1 of the present invention after being used together;

[0048] Figure 15 This is a schematic diagram after release in Example 1 of the present invention;

[0049] Figure 16 Schematic diagram of the structure of the fixator in Example 1 of the present invention;

[0050] Figure 17 This is a schematic diagram of the connection of the three-lumen tube in Example 1 of the present invention;

[0051] Figure 18 This is a schematic diagram of the position of the loader in Example 1 of the present invention;

[0052] Figure 19 Schematic diagram of the structure of the loader in Example 1 of the present invention;

[0053] Figure 20 Schematic diagram of the stent graft being delivered to a target location in Example 1 of the present invention;

[0054] Figure 21 Schematic diagram of the stent graft in Example 1 of the present invention in a semi-expanded state after the first release and a blood flow diagram;

[0055] Figure 22 Schematic diagram of the stent graft in Example 1 of the present invention in a fully deployed state;

[0056] Figure 23 Schematic diagram of blood flow when the covered stent is in a fully expanded state after the second release in Example 1 of the present invention.

[0057] Figure 24 This is a schematic diagram of the stent graft being tightened in Example 2 of the present invention;

[0058] Figure 25 Schematic diagram of a single fastening clip of the stent graft in Example 2 of the present invention;

[0059] Figure 26 This is a schematic diagram of the stent graft being tightened in Example 1 of the present invention;

[0060] Figure 27 This is a schematic diagram of an implementation of a single fastening clip of the stent graft in Example 1 of the present invention;

[0061] Figure 28 This is a schematic diagram of the stent graft being tightened in Example 1 of the present invention;

[0062] Figure 29 Schematic diagram of another embodiment of a single fastening clip of the stent graft in Example 1 of the present invention;

[0063] Figure 30 This is a schematic diagram of the stent graft being tightened in Example 1 of the present invention;

[0064] Figure 31 Schematic diagram of the third embodiment of a single fastening clip of the stent graft in Example 1 of the present invention. DETAILED DESCRIPTION

[0065] The adaptive transthoracic aortic stent graft and its system provided by the present invention are further described in detail and completely in conjunction with the following embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0066] Example 1

[0067] The adaptive trans-arch aortic covered stent provided by the present invention is shown in the structural diagram in the expanded state unless otherwise specified in order to better illustrate the stent structure provided by the present invention. Figure 1 is a three-dimensional diagram of the adaptive cross-arch stent graft of this embodiment, as shown in FIG. Figure 1As shown, the stent comprises a main body 1 and a fastening portion 2. The main body 1 includes a metal stent component 3 and a coating 4. The metal stent component 3 supports the coating 4 to form a coated stent. The main body 1 is made of a flexible material and can adapt to the shape of a blood vessel, such as the aortic arch, to facilitate insertion and post-fixation operation. As a preferred embodiment, the metal stent component may be provided with a sealing stent 5, a first metal stent 6, a second metal stent 7, and a third metal stent 8. The number of metal stents depends on the desired surgical procedure and is not intended to limit the present invention.

[0068] The fastening portion 2 is used to tighten and fix the contracted state of the stent graft, so that it can enter the blood vessel in a very small size during the operation. The fastening portion 2 also contacts and constrains the stent graft after it reaches the treatment position, thereby controlling the multiple deployments of the stent graft, such as Figure 3 As shown, the fastening portion 2 is divided into a first fastening member 201 and a second fastening member 202. The first fastening member 201 and the second fastening member 202 are released one by one in sequence, and when the first fastening member is released, the second fastening member can still constrain the coated stent to a non-fully expanded state. As a preferred embodiment, the second fastening member 202 can constrain the coated stent to 40% to 70% of the design diameter, and fully expand to 100% of the design diameter.

[0069] The first fastening member 201 and the second fastening member 202 are both provided with a plurality of fastening clips 203, such as Figure 1 As shown, the fastening clamps 203 of the first fastening member and the second fastening member are alternately arranged in sequence along the axial direction of the coated support. Each fastening clamp 203 has a pair of fastening arms 204. One end of the paired fastening arms is fixed to the coated support body by hinged or sutured methods, and the other end is provided with a fastening hole 605. The fastening holes are overlapped and fixed by a core wire. Figure 2 (a) is a cross-sectional view of a single fastening clamp 203 and a fastening arm 204 constraining the coated support. Figure 2 (b) is a structural schematic diagram of a single fastening clamp, as shown in FIG. Figure 2(a)-2(b)As shown, each pair of fastening arms is fastened into a ring to tighten the stent graft into a contracted state. It is worth mentioning that the inventors pioneered the method of realizing multiple deployment of the stent graft, wherein the first fastening member 201 and the second fastening member 202 are fastened and contracted by different core wires to tighten the stent graft, and the maximum lengths of the fastening arms of the first fastening member 201 and the second fastening member are different. In other words, when the first core wire 1101 of the first fastening member 201 is withdrawn, the fixing arms of the first fastening member 201 lose their restraining force and thus extend. At this time, the stent graft is deployed to the tightened and contracted state of the second fastening member, and the stent graft is in a partially non-fully deployed state. The first fastening member 201 preferably tightens the stent graft into an axially contracted state, which not only enables the stent graft to be loaded into a cooperating delivery system through the first fastening member for delivery to the surgical vessel, but also enables the stent graft to be delivered through a thinner sheath as much as possible or the delivery system can be made thinner. Similarly, when the second core wire 1102 of the second fastening member 202 is withdrawn, the second fastening member 202 loses its restraint on the stent graft and expands. The stent graft is now fully deployed to the same diameter as the vessel in the adaptive treatment position, and the stent graft fully expands on its own. To facilitate differentiation between the two fastening members, the fastening arms can be configured with different diameters, such as a larger diameter for the second fastening member than for the first.

[0070] Figure 3 The diagram is a structural diagram of the tapered head of the stent graft delivery system. The stent graft and the delivery system together constitute a system for completing thoracic aortic arch surgery. Figure 3 As shown, the delivery system includes a tapered head 9 , a marker 10 , a core wire 11 , a pull wire handle 12 , a fixer 13 , a core shaft tube 14 , a support tube 15 , a handheld portion 16 , a tail end connector 17 and a loader 18 .

[0071] A mark 10 is provided on the conical head 9, and the mark can be a development mark, for example, which can be developed under X-ray images. Figure 4 is a schematic diagram of the cone head structure, as shown in Figure 4 As shown, the mark 10 is composed of an axial mark 1001 and a radial mark 1002. The axial mark 1001 is parallel to the core shaft tube 14, and the radial mark 1002 is perpendicular to the plane formed by the axial mark 1001 and the core shaft tube 14. Among them, the development shape of the axial mark 1001 can be a bar, parallel to the guide wire, and basically blocked by the hardened guide wire. The shape of the radial mark 1002 can be a rectangle perpendicular to the plane where the guide wire is located. As a preferred embodiment, the guide wire is selected to be a hardened guide wire.

[0072] The core wire 11 is composed of two core wires, such as Figure 5As shown, the core wire tied to the first fastener 201 is named the first core wire 1101, and the core wire tied to the second fastener 202 is named the second core wire 1102. The end of the delivery system is provided with a pull wire handle 12 connected to the core wire 11, and the pull wire handles connecting the first core wire 1101 and the second core wire 1102 are named the first pull wire handle 1201 and the second pull wire handle 1202. Figure 6 As shown, the first pull wire handle 1201 and the second pull wire handle 1202 fixed at the hand-held part 16 are cleverly matched with each other, so that the pulling order of the first pull wire handle 1201 and the second pull wire handle 1202 must be that the first pull wire handle 1201 is pulled out before the second pull wire handle 1202 is pulled out, which can effectively avoid the failure of the semi-release function of the first deployment due to the wrong operation sequence.

[0073] In this embodiment, Figures 6 to 9 As shown, the handle of the first wire pull handle 1201 is provided with an L-shaped groove 1203c, and a pull ring is provided at one end, and the L-shaped groove 1203c runs through the side away from the pull ring. The handle of the second wire pull handle 1202 is provided with a protruding connecting piece 1203b. The length of the first wire pull handle 1201 is longer than the length of the second wire pull handle 1202. The hand-held portion 16 is composed of two symmetrical shells, one of which is provided with two slots 1207, and a connecting groove 1208 is provided between the two slots 1207. The slots 1207 are used for the insertion of the wire pull handle, and the connecting groove 1207 is used for the passage of the connecting piece 1203b. The shell is also provided with a limiter 1204, which is located in the middle of the first wire pull handle 1201 and the second wire pull handle 1202. The limiter 1204 is fixed to the shell and is located inside the hand-held portion 16. When in use, first insert the first pull-wire handle 1201 and the second pull-wire handle 1202 into the hand-held part through the slot 1207, and then rotate the second pull-wire handle 1202 so that the connector 1203b is inserted into the short side along the long side of the L-shaped slot 1203c for fixation. When the first pull-wire handle 1201 is not withdrawn from the hand-held part 16, due to the presence of the connector 1203b and the L-shaped slot 1203c, the second pull-wire handle 1202 cannot be rotated or pulled out, preventing the bracket from being released during transportation or released by mistake. The structural design of the first pull-wire handle 1201 and the second pull-wire handle 1202 ensures precise positioning during the release process. In conjunction with the use of double bundling and metal wires (i.e., the first fastener 201, the second fastener 202, the first core wire 1101, and the second core wire 1102) at the main body 1 of the stent graft to tie the stent graft in a compressed state, the rear release structure can realize the first release (i.e., semi-expansion) and second release (i.e., full expansion) of the transthoracic aorta stent graft, and the first and second release processes will not block blood flow, effectively avoiding inaccurate release position caused by blood flow impact.

[0074] Another possible implementation of the pull wire handle is: Figure 10-15 As shown, in this embodiment, the first wire pull handle 1201 and the second wire pull handle 1202 are respectively composed of a handle body and a pull ring. The length of the handle body of the first wire pull handle 1201 is longer than the length of the handle body of the second wire pull handle 1202. The handle body of the second wire pull handle 1202 is provided with a protrusion 1203a. Correspondingly, a sleeve is provided at the end of the hand-held portion 16. The sleeve is fixed on the hand-held portion. A groove that can cooperate with the protrusion 1203a is provided in the sleeve, but the groove is not a through groove along the inner wall of the sleeve. The size of the groove is slightly larger than the protrusion 1203a. The inner cavity of the sleeve is the size of the handle bodies of the two wire pull handles, that is, the inner cavity of the sleeve just accommodates the handle bodies of the two wire pull handles. When in use, first extend the handle body of the second wire pull handle 1202 into the sleeve, and the protrusion 1203a is stuck in the groove, and then extend the handle body of the first wire pull handle 1201 into the sleeve. When pulling out, first withdraw the first pull wire handle 1201 so that the gap left in the sleeve is larger than the width of the second pull wire handle 1202, then pull the pull ring to first move the protrusion 1203a out of the groove, and then withdraw the second pull wire handle 1202.

[0075] like Figure 16 As shown, the fixator 13 is composed of a fixing ring 1301 and a fixing core wire 1302. The fixing ring 1301 is a double-hole structure, with the large hole being sleeved on the core shaft tube 14, and the end of the fixing core wire 1302 being inserted into the small hole. A clothes fork-shaped structure (h-shaped) is formed on the core shaft tube 14 by the fixator 13. The core shaft tube 14 runs through the entire delivery system from the inside of the conical head 9 to the tail end connector 17 at the end, serving as a channel for tracking the guide wire and connecting the entire delivery system. Figure 19 As shown, the support tube 15 is sleeved after the core shaft tube 14 support section to the inside of the handheld part 16, and is composed of a three-lumen tube 1501 and a thickening layer 1502, and the thickening layer is a reinforced steel tube. The three-lumen tube 1501 has three cavities, forming three channels running through the entire support tube 15, the core shaft tube cavity 15011 is located in the innermost layer of the support tube 15, and is coaxially sleeved with the outer wall of the core shaft tube 14. The other two cavities serve as channels for the core wire, namely the first core wire cavity 15012 and the second core wire cavity 15013. The three-lumen tube 1501 is located in the part outside the body and is sleeved with metal tubing to increase strength, such as stainless steel pipe as a reinforced steel pipe, to enhance the operability of the conveying system. The thickening layer 1502 is sleeved on the outer wall of the three-lumen tube 1501 to make the three-lumen tube 1501 transition smoothly, so that the conveying system can proceed smoothly when entering the adjustable sheath or the adjustable valve sheath is withdrawn. A hand-grip portion 16 is provided at the rear end of the support tube 15 , and the hand-grip portion 16 is used to facilitate grasping and fixing the first pull-wire handle 1201 and the second pull-wire handle 1202 during operation.

[0076] The loader 18 is used to flush and exhaust the membrane and allow the stent graft to pass smoothly through the hemostatic valve of the adjustable valve sheath. Figure 18and 19 As shown, the loader 18 includes a tube body 1801 , a side tube 1802 , a valve 1803 , a seat 1804 , and a hemostatic valve 1805 .

[0077] The proximal end of the stent graft is fixed by a fixator, which facilitates the delivery system to push the stent graft in the sheath and to accurately position the stent graft at the lesion (to avoid the stent graft from moving backward relative to the delivery system when pushing and withdrawing the core wire 11). The fixed core wire 1302 on the fixator 13 ties the coil on the inner side of the front end of the stent body 1, thereby fixing the proximal end of the stent graft of the present invention. In this way, under the condition that the front end of the stent is constrained by the fixator, the stent graft can maintain an unchanged axial position with the delivery system during delivery, initial release and full deployment, ensuring the precise release of the stent graft. After the stent graft is fully released, the stent graft is anchored in the blood vessel. When the delivery system is withdrawn, the fixed core wire 1302 on the fixator 13 is pulled out of the coil on the inner side of the front end of the stent body 1, and the stent graft is then released from the connection with the delivery system. It is not difficult to see that because the delivery system of the present invention has no outer sheath itself, it has good flexibility. The sheath and the delivery system pass through the arch respectively, and the delivery system passes through the arch in the sheath, so that the delivery system can easily push the stent graft across the arterial arch.

[0078] The surgical operation of the covered stent and system of this embodiment is as follows. In order to better illustrate the surgical operation of the covered stent provided by the present invention, this embodiment uses the aortic arch three-branch reconstruction surgery with higher surgical difficulty for illustration. Accordingly, due to surgical needs, the covered stent is also provided with an embedded branch portion, and the embedded branch portion is provided with three embedded branch stents arranged in the same trunk for subsequent three-branch reconstruction, which does not affect the design essence of multiple releases of the present invention, so it is illustrated here. Figure 20-23 Schematic diagram of the reconstruction process.

[0079] like Figure 20As shown, when the covered stent is implanted, the adjustable valve sheath is first delivered to the ascending aorta, and then the stent delivery system is delivered from the adjustable valve sheath. During the delivery to the target blood vessel, the stent does not contact the blood vessel wall, effectively avoiding damage to the blood vessel wall during the delivery process of the stent. When the delivery system pushes the covered stent to the arterial arch, the mark 10 on the conical head 9 is used to confirm whether the embedded branch and the inner collapsed platform of the covered stent are located on the greater curvature side. If the accurate position is not reached, the delivery system is rotated to align the embedded branch and the inner collapsed platform with the side wall of the greater curvature of the aorta. Specifically, the delivery system is rotated to make the radial mark 1002 face the greater curvature side, and at the same time, when the axial mark 1001 is basically overlapped with the guide wire, it represents that the opening of the embedded branch is facing the top of the arterial arch. Combined with the mark at the entrance of the embedded branch, it is delivered to the leading edge of the opening of the brachiocephalic trunk blood vessel to achieve accurate positioning of the covered stent, so that the covered stent enters the target position. Since the fixator fixes the proximal end of the stent graft, the delivery system pushes the stent graft in the sheath and can accurately position the stent graft at the lesion (to avoid the stent graft from moving backward relative to the delivery system when pushing and withdrawing the core wire 11).

[0080] After the delivery system delivers the stent graft to its proper position, first pull the pull handle 1201 of the first core wire 1101 (there is no specific correspondence between the fasteners, the core wire, and the pull handle. This embodiment is only used to illustrate the secondary release process of the stent graft body). The core wire 1101 is pulled out from the first fastener 201, and the first fastener 201 loses its constraint on the stent graft. The stent graft is unfolded to a state constrained by the second fastener 202. At this time, the stent graft is in a partially unfolded state (e.g., a semi-expanded state). Figure 21 As shown. After the stent is delivered to its place, first withdraw the adjustable valve sheath until the front end of the sheath is located behind the end of the stent. Then pull back the pull wire handle 1201 connected to the core wire 1101 to complete the first release of the stent, so that the stent body is in a semi-expanded state. At this time, the blood flow in the aorta is diverted for the first time and is divided into three directions. The first flow flows in from the ascending aorta section of the covered stent body and is diverted to the embedded branch part and the inner collapsed platform, and then enters the three branch arteries of the aortic arch to form the first pathway, thereby ensuring the blood supply of the three branches; in addition, since the covered stent is in a semi-expanded state, the remaining two blood flows flow out of the aortic arch from inside the covered stent body and outside the covered stent body (that is, the original pathway of the blood vessel itself).

[0081] It is worth emphasizing that, unlike the prior art where all coated stents are released in place at once, since the stent is not attached to the blood vessel wall after the first release, the fixator also fixes the proximal end of the coated stent. Under this condition, the release position can be further adjusted, so that the coating can be easily and accurately positioned in the axial and circumferential directions through the delivery system. When the first pull-wire handle 1201 is pulled out, the limit of the pull-wire handle 1202 is released, and the pull-wire handle 1202 connected to the core wire 1102 can be pulled back to pull the second core wire 1102 out of the second fastener 202. The second fastener 202 loses its constraint on the coated stent, and the coated stent fully expands on its own. Figure 22 As shown. The secondary release is completed by pulling back the pull wire handle 1202 connected to the core wire 1102. Since the fixed core wire 1302 on the fixator 13 ties the coil on the inner side of the front end of the stent body 1 and fixes the proximal end of the coated stent, under the condition that the front end of the stent is constrained by the fixator, the coated stent can maintain the same axial position with the delivery system during delivery, initial release and full deployment, and will not be affected by the impact of blood flow and affect the positioning, thereby ensuring the precise release of the coated stent. After the coated stent is fully released, the coated stent is anchored in the blood vessel. When the delivery system is withdrawn, the fixed core wire 1302 on the fixator 13 pulls out the coil on the inner side of the front end of the stent body 1, and the coated stent is released from the delivery system, as shown Figure 23 At this point, blood flow in the aorta is diverted a second time, splitting into two directions. The first flow still flows from the ascending aorta segment of the stent graft body, is diverted to the embedded branch, and then enters the three branch arteries of the aortic arch, forming the first pathway. The second flow, due to the complete deployment of the stent graft body, all remaining blood flows out through the stent graft body into the descending aorta. At this time, blood flow in the stent and in the branches above the aortic arch can always remain unobstructed.

[0082] From the above, it is clear that the covered stent of the present invention does not block blood flow during either the initial or secondary release process during surgery (blood flow outside the stent remains unobstructed during the initial release, and blood flow inside the stent remains unobstructed during the secondary release). Furthermore, it acts as a fixator, preventing stent displacement caused by blood flow impact and enabling precise release. This facilitates subsequent bridging of branch vessels and avoids bridging failure and branch vessel occlusion.

[0083] As mentioned above, the covered stent of this embodiment can be used to complete various interventional surgeries such as three-branch aortic arch reconstruction, which can be completed quickly with a short operation time, which is conducive to the promotion of surgery, improving postoperative effects and reducing complications.

[0084] Example 2

[0085] The difference between this embodiment and embodiment 1 is that each fastening member 203 of the fastening portion 2 can also be simplified to a single arm, such as Figure 24 and25 As shown, any non-endpoint portion of a single securing arm 204, such as the middle section, can be secured to the stent graft body. The single securing arm has securing holes at both ends. When the securing holes overlap, the stent graft is secured and tightened via a core wire. Both the first securing member 201 and the second securing member 203 can be secured by contracting the stent using this single securing arm 204. The stent deployment method is as described above and will not be further described here.

[0086] Example 3

[0087] The difference between this embodiment and embodiment 1 is that the fastener 203 can also be a single rope with a single free end or small rings at both ends, and can be designed in various ways, such as Figure 26 and 27 As shown, the middle part of the fastener 203 is fixed on the main frame, and the two ends are free ends, one free end is a coil structure, and the other free end is a single rope structure with a ring at the end. Figure 28 and 29 As shown, the middle part of the fastener 203 is fixed on the main frame, and the two ends are free ends, and the free ends are single rope structures with rings at the ends. Figure 30 and 31 As shown, one end of the fastener 203 is fixed on the main frame, and the other end is the free end, which is a single rope structure with a ring at the end.

[0088] The implementation methods of the fasteners in the above embodiments can be designed according to the actual application scenarios, or one or more implementation methods of any fastener in Examples 1-3 can be selected and used in combination. The above embodiments do not limit the fastening portion of the coated bracket of the present invention to only use the same implementation method of the fastener.

[0089] Finally, it is necessary to explain here that the above embodiments are only used to further illustrate the technical solution of the present invention in detail and cannot be understood as limiting the scope of protection of the present invention. Any technician familiar with this profession, without departing from the scope of the technical solution of this application, can make slight changes, modifications, substitutions, combinations, and simplifications using the above-disclosed technical content, which should be equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A multiple-release covered stent, characterized by: The stent graft comprises a stent body and a fastening portion, wherein the stent body comprises a metal stent and a membrane, the metal stent supports the membrane to form the stent graft, the fastening portion is used to tighten and fix the stent graft in a contracted state before entering the blood vessel during surgery, and the fastening portion also controls the secondary expansion of the stent graft after the stent graft reaches the treatment position; The fastening portion includes a first fastening member and a second fastening member, the first fastening member and the second fastening member are released one by one in sequence, and when the first fastening member is released, the second fastening member still constrains the stent graft to a non-fully deployed state; The first fastener and the second fastener are fastened and tightened by different core wires to shrink the coated stent. When the first core wire of the first fastener is pulled out, the fixing arm of the first fastener loses its restraining force and thus stretches its arm. At this time, the coated stent is expanded to the fixed and contracted state of the second fastener, and the coated stent is in a non-fully expanded state; when the second core wire of the second fastener is pulled out, the second fastener loses its restraint on the coated stent and stretches its arm. At this time, the coated stent is completed and expanded to the same diameter of the blood vessel in the adaptive treatment position, and the coated stent fully expands by itself; the first fastener and the second fastener are fastened and tightened by different core wires to shrink the coated stent, and the maximum length of the fixing arm or fixing arm of the first fastener and the fixing arm or fixing arm of the second fastener are different; the first fastener and the second fastener are both provided with a plurality of paired fixing arms or single fixing arms, and the fixing arms or fixing arms are fastened and tightened by a core wire to shrink the coated stent.

2. The multiple-release stent graft according to claim 1, characterized in that: The second fastener constrains the stent graft to 40% to 70% of the designed diameter of the stent graft.

3. The multiple-release covered stent according to claim 1, characterized in that: One end of the paired fastening arms is hinged or sutured to the main body of the stent graft, and the other end is provided with a fastening hole. After the fastening holes are overlapped, they are fastened and tightened by a core wire.

4. The multiple-release covered stent according to claim 1, characterized in that: Any non-end point portion of the single fixing arm is fixed to the stent body, and fixing holes are provided at both ends of the single fixing arm. After the fixing holes at both ends overlap, they are fastened and tightened by the core wire.

5. A stent graft system, characterized in that: The coated stent according to any one of claims 1 to 4 is used in conjunction with a delivery system, wherein the delivery system includes a conical head, a marker, a core wire, a pull wire handle, a fixer, a core shaft tube, a support tube, a handheld part, a tail end connector and a loader.

6. The stent graft system according to claim 5, characterized in that: The core wire is composed of two core wires, which are divided into a first core wire and a second core wire, wherein the core wire that ties the first fastener is the first core wire, and the core wire that ties the second fastener is the second core wire. A pull wire handle connecting the core wires is provided at the end of the conveying system, and the pull wire handles connecting the first core wire and the second core wire are the first pull wire handle and the second pull wire handle. Through the cooperation of the first pull wire handle and the second pull wire handle, the retreat order of the first pull wire handle and the second pull wire handle is to pull out the first pull wire handle and then pull out the second pull wire handle.

7. The stent graft system according to claim 6, wherein: The first pull-wire handle is provided with a card slot, and the second pull-wire handle is provided with a protruding connecting piece. The length of the first pull-wire handle is longer than that of the second pull-wire handle; the hand-held part is provided with two slots, each slot is suitable for a pull-wire handle to pass through; when in use, the first pull-wire handle and the second pull-wire handle are inserted into the hand-held part through the slots, and then the second pull-wire handle is rotated to make the connecting piece snap into the card slot.

8. The stent graft system according to claim 6, wherein: The length of the first pull-wire handle is longer than that of the second pull-wire handle. The second pull-wire handle is provided with a protrusion. The hand-holding part is provided with a sleeve for inserting the first pull-wire handle and the second pull-wire handle. The sleeve is provided with a groove that cooperates with the protrusion; when in use, the protrusion is inserted into the groove to limit the first pull-wire handle and the second pull-wire handle.

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