Vascular sheath structure with variable diameter

Abstract

The utility model relates to a diameter-variable blood vessel sheath structure, which solves a series of problems of large operative wound, incapability of intraoperative radiography and the like in the process of treating lower limb artery embolism by opening a Fogarty catheter to take thrombus. The device comprises an outer sheath, an inner sheath and a sheath core which are sequentially nested from outside to inside, the outer sheath comprises an outer sheath main body and an outer sheath base arranged at the near end of the outer sheath main body; the inner sheath comprises an inner sheath body, an inner sheath base is arranged at the near end of the inner sheath body and connected with a hemostasis valve, the far end of the inner sheath body is connected with a self-expansion covered stent sample structure with two open ends, and the length of the inner sheath is larger than that of the outer sheath. The sheath core comprises a sheath core body, a sheath core base is arranged at the near end of the sheath core body, a conical end with the outer diameter gradually reduced is arranged at the far end of the sheath core body, a middle hole for a guide wire to penetrate through is formed in the sheath core body, and the length of the sheath core is larger than that of the inner sheath. The utility model has the advantages of high effectiveness, high safety, strong adaptability, good adaptability, simple structure and convenient operation.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and to a vascular embolization treatment device, particularly to a vascular sheath structure with variable diameter. Background Technology

[0002] Acute lower extremity arterial embolism is a serious ischemic disease of the lower extremities, with an annual incidence of approximately 1.5 cases per 10,000 people. Middle-aged and elderly patients are the main affected population. The cause of acute lower extremity arterial embolism is usually a thrombus that breaks off from the wall of the heart or a major artery and travels with the bloodstream to block the distal lower extremity arteries, causing an interruption of blood flow. This can lead to ischemia and necrosis of the lower extremities within a short period, and in severe cases, can result in systemic infection, sepsis, amputation, or even death. Due to the rapid onset of the disease, timely, complete, and thorough removal of the embolus and restoration of forward blood flow are crucial to saving ischemic tissue.

[0003] Currently, the treatment of acute lower extremity arterial embolism remains a challenge in vascular surgery. Existing main treatment measures include...

[0004] Option 1:

[0005] 1) Technical Solution: Open thrombectomy using a Fogarty catheter: After anesthesia, a 10cm skin incision is made in the groin to expose the femoral artery. Under direct vision, blood flow to the femoral artery is blocked. After the femoral artery is cut open, a Fogarty catheter with an inflatable balloon is inserted to the location of the thrombus. The balloon is inflated, and the thrombus is removed, restoring vascular patency. This technique is suitable for treating acute lower extremity arterial embolism, especially those caused by cardiac emboli. The procedure must be performed under general anesthesia.

[0006] 2) Disadvantages: ① Patients require general anesthesia, which carries inherent risks, especially for elderly patients;

[0007] ②A 10cm incision is required in the groin, which is a major trauma and carries risks such as surgical infection, poor wound healing, fat liquefaction, and lymphatic leakage.

[0008] ③ The femoral artery blood flow was blocked during the procedure, which led to a. the easy induction of new thrombi; b. the inability to conduct simultaneous angiography to assess whether the thrombi had been completely removed;

[0009] ④ It is impossible to continue interventional procedures such as balloon dilation and stent implantation simultaneously. If further interventional treatment of the diseased blood vessel is required, the femoral artery incision site must be sutured first, the vascular sheath must be reinserted, and then the interventional procedure can be continued through the vascular sheath.

[0010] ⑤ Once angiography reveals residual thrombus after vascular suturing, further treatment is required. This necessitates re-blocking and cutting the femoral artery, inserting a thrombectomy catheter, and repeating the process, which is tedious and complex.

[0011] ⑥ New stenosis may occur after the cut blood vessel site is sutured.

[0012] Option 2:

[0013] 1) Technical Solution: Catheter-guided thrombolysis: Catheter-guided thrombolysis refers to the percutaneous insertion of a thrombolytic catheter into the target blood vessel under DSA or ultrasound guidance. Thrombolytic drugs are then directly infused into the thrombus site through the catheter to dissolve the formed thrombus and restore vascular patency. The infusion time for thrombolytic drugs is usually greater than 12 hours.

[0014] 2) Disadvantages: ① Catheter-directed thrombolysis can often only dissolve fresh thrombi that develop on the basis of old thrombi, while thrombi that break off from the heart are often old thrombi that are difficult to dissolve.

[0015] ② Catheter-directed thrombolysis requires time to dissolve the thrombus and has a slow onset of action. Furthermore, patients with acute arterial embolism face the risk of limb necrosis due to prolonged ischemia.

[0016] ③ Catheter thrombolysis takes a long time to restore arterial blood flow (low-pressure perfusion), causing perfusion injury.

[0017] ④ Bleeding is the most common complication of catheter-directed thrombolysis, with intracranial hemorrhage being the most serious complication.

[0018] ⑤ Risks of infection and catheter displacement associated with prolonged catheter placement.

[0019] Option 3:

[0020] 1) Technical solution: Mechanical thrombectomy catheter aspiration, commonly used catheters include AngioJet and Rotarex (Straub) thrombectomy catheters. The procedure involves percutaneous puncture of the artery to insert the thrombectomy catheter, which is then inserted into the thrombus for aspiration.

[0021] 2) Disadvantages: ① Catheter-assisted thrombectomy is difficult to completely remove thrombi. Regardless of the type of thrombectomy catheter, there is a certain thrombus removal rate, and it is difficult to completely remove thrombi, especially for old thrombi originating from the heart, the removal efficiency is even lower.

[0022] ②During the process of clearing the thrombus, small emboli may occur and block distal arterioles along the direction of blood flow.

[0023] ③Because the diameter of the artery below the knee is small, the above-mentioned mechanical embolization catheter device is difficult to use in embolism involving the artery below the knee.

[0024] ④ Mechanical thrombectomy catheters are expensive.

[0025] Since middle-aged and elderly patients are the main affected population for this disease, they often have multiple underlying diseases. Furthermore, due to age-related vascular degeneration and atherosclerosis, vascular fragility increases, leading to variations in the effectiveness and safety of different treatment methods. Among these, the classic and mainstream surgical procedure for treating acute lower extremity arterial embolism involves dissecting and exposing the femoral artery under general anesthesia, followed by thrombectomy using a Fogarty catheter. At the start of the procedure, a 10cm skin incision is made at the femoral artery bifurcation point. The femoral artery is then dissected and exposed layer by layer. Blood flow to the femoral artery is then blocked, and the femoral artery is cut open before inserting the Fogarty thrombectomy catheter. Under fluoroscopy, the catheter is advanced to the distal end of the embolic artery. The distal balloon of the Fogarty thrombectomy catheter is then inflated. Pulling back the inflated balloon allows the thrombus to be removed from the cut femoral artery. Open thrombectomy using the Fogarty catheter is currently the main treatment for lower extremity arterial embolism, but it still has many drawbacks: 1) Open thrombectomy using the Fogarty catheter requires prolonged and complete occlusion of proximal lower extremity arterial blood flow, which may induce the formation of new thrombi during the procedure; 2) Because it requires complete occlusion of proximal lower extremity arterial blood flow, it is impossible to simultaneously perform angiography to verify whether the thrombus has been completely removed, and if vascular injury occurs during the thrombectomy, interventional procedures such as balloon dilation and stent implantation cannot be performed concurrently; 3) When angiography is required, the Fogarty catheter must be completely withdrawn, the femoral artery incision sutured, and a vascular sheath inserted for angiography. If the angiography is unsatisfactory and thrombectomy is required again, the sutured femoral artery incision must be reopened, and the Fogarty catheter reinserted. The process is cumbersome and complex, and may induce new thrombi, leading to an increase in the number of thrombi removed. 4) Open thrombectomy requires general anesthesia. The surgery is highly invasive, and the risks of anesthesia and surgery are very high for patients with atrial fibrillation or who are elderly. Utility Model Content

[0026] The purpose of this invention is to solve a series of problems in the treatment of lower extremity arterial embolism using traditional Fogarty catheter open thrombectomy, such as large surgical trauma, high risk, and inability to perform intraoperative angiography. This invention provides a variable-diameter vascular sheath structure that can be percutaneously implanted into the artery under local anesthesia, reducing surgical trauma. Furthermore, the outer sheath's constraint and release during the expansion and contraction of the inner sheath, combined with the Fogarty catheter, facilitates thrombectomy. Post-thrombectomy angiography and subsequent interventional procedures can be performed directly without suturing the vessel or changing the access device.

[0027] The technical solution adopted by this utility model to solve its technical problem is: a variable diameter vascular sheath structure, characterized in that: an outer sheath, an inner sheath, and a sheath core are nested sequentially from the outside to the inside; the outer sheath is a hollow flexible tube with openings at both ends, the outer sheath includes an outer sheath body and an outer sheath base disposed at the proximal end of the outer sheath body; the inner sheath is a hollow flexible tube with openings at both ends, the inner sheath includes an inner sheath body, an inner sheath base disposed at the proximal end of the inner sheath body, and a self-expanding stent with openings at both ends is connected to the distal end of the inner sheath body, the length of the inner sheath is greater than that of the outer sheath; the sheath core is a flexible flexible tube, the sheath core includes a sheath core body, a sheath core base disposed at the proximal end of the sheath core body, and a tapered end with a gradually decreasing outer diameter at the distal end of the sheath core body, the sheath core body has a central hole for inserting a guidewire, and the length of the sheath core is greater than that of the inner sheath.

[0028] In the original Fogarty catheter thrombectomy, a guidewire was passed through the thrombus site, and then the Fogarty catheter was advanced along the guidewire. The Fogarty catheter had an inflatable balloon distal to the thrombus site, through which the thrombus was removed. The original Fogarty catheter thrombectomy procedure used an open surgery approach, requiring the patient to undergo the procedure under general anesthesia. For elderly patients or those in poor general condition, who could not tolerate anesthesia, the risks of anesthesia itself were significant. Verifying the effectiveness of open thrombectomy required angiography, necessitating complete withdrawal of the Fogarty catheter, suturing the femoral artery incision, inserting a vascular sheath, and then angiography. If the angiography was unsatisfactory, thrombectomy needed to be repeated, requiring reopening the sutured femoral artery incision and reinserting the Fogarty catheter. This process was cumbersome, complex, and prolonged, potentially requiring repeated procedures, posing a significant challenge to both patients and physicians. This device can be used in conjunction with the existing Fogarty guidewire balloon to perform minimally invasive thrombectomy. Compared with traditional open surgery, it does not require general anesthesia, is safer, and can provide real-time angiography during the operation. It eliminates the need for repeated suturing and cutting, greatly simplifying the operation and effectively shortening the operation time.

[0029] Preferably, the self-expanding support has a mesh structure.

[0030] Preferably, the self-expanding stent is a self-expanding covered stent, and both the inner and outer walls of the self-expanding stent are provided with an elastic covered layer to prevent scratching the blood vessel wall.

[0031] Preferably, the connection between the self-expanding support and the inner sheath body is tapered.

[0032] Preferably, when the inner sheath base abuts against the end face of the outer sheath base, the self-expanding support extends completely beyond the end of the outer sheath body.

[0033] Preferably, a hemostatic valve is detachably connected to the proximal end of the inner sheath base, and the hemostatic valve is connected to a three-way valve via an extension tube.

[0034] Preferably, the three-way valve has three openings, and in addition to the opening connected to the extension pipe, the other two openings are equipped with protective caps.

[0035] Preferably, the outer sheath body has an outer diameter of 5F-18F and a length of 20-110cm; the inner sheath body has an outer diameter of 4F-16F (F stands for Fr, French is a unit of sheath size, 1F is approximately equal to 1 / 3mm) and a length of 30-120cm; the sheath core body has a length of 40-140cm.

[0036] Preferably, the self-expanding bracket is firmly connected to the distal end of the inner sheath body, and the diameter of the self-expanding bracket after expansion is 3mm-12mm and the length is 4mm-20mm.

[0037] This utility model has the following beneficial effects:

[0038] (1) High effectiveness. The tip of the self-expanding stent adheres well to the vessel wall during expansion. When used in conjunction with the Fogarty thrombectomy catheter, it can completely collect the captured thrombus, effectively avoiding the possibility of thrombus or plaque dislodging when the thrombectomy balloon is withdrawn, thus improving thrombus capture efficiency.

[0039] (2) High safety. The percutaneous implantation of this vascular sheath can be performed under local anesthesia. It is minimally invasive, has a fast recovery, and few postoperative complications. After thrombectomy, the thrombectomy balloon is withdrawn from the vessel through the channel formed by the self-expanding stent and the inner sheath, reducing the damage to the vascular intima caused by withdrawal. When there are vascular lesions that require simultaneous balloon dilation or stent implantation, the procedure can continue through this vascular sheath, reducing the number of steps required.

[0040] (3) It has strong adaptability and good compatibility. By adjusting the expansion degree of the self-expanding stent, it can be adapted to blood vessels of various sizes, and the stenotic segment of the blood vessel can be passed smoothly, ensuring the smooth progress of the thrombectomy.

[0041] (4) Simple structure and easy operation. Attached Figure Description

[0042] The present invention will be further described below with reference to the accompanying drawings.

[0043] Figure 1 This is a schematic diagram of the non-working state structure of this utility model.

[0044] Figure 2 This is a schematic diagram of the working state structure of this utility model.

[0045] Figure 3 This is a schematic diagram of a split structure of this utility model.

[0046] Figure 4 This is a schematic diagram of the vascular sheath insertion process of this utility model.

[0047] Figure 5 This is a schematic diagram of the thrombectomy process using a vascular sheath according to this utility model.

[0048] In the diagram: 1: Outer sheath body; 2: Inner sheath body; 3: Sheath core body; 4: Hemostatic valve; 5: Extension tube; 6: Three-way connecting valve; 7: Protective cap; 8: Outer sheath base; 9: Inner sheath base; 10: Sheath core base; 11: Self-expanding stent; 12: Outer sheath; 13: Hemostatic device; 14: Inner sheath; 15: Sheath core. Detailed Implementation

[0049] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0050] Example: A vascular sheath structure with variable diameter, such as Figure 1 , 2 As shown in Figure 3, this device consists of an outer sheath 12, an inner sheath 14, and a sheath core 15 nested sequentially from the outside in. The outer sheath 12 is a hollow flexible tube open at both ends, comprising an outer sheath body and an outer sheath base 8 located near the proximal end of the outer sheath body 1. The inner sheath 14 is a hollow flexible tube open at both ends, comprising an inner sheath body 2, with an inner sheath base 9 located near the proximal end of the inner sheath body. A self-expanding support 11 with open ends is connected to the distal end of the inner sheath body. The length of the inner sheath body 2 is greater than that of the outer sheath body 1. When the inner sheath base 9 abuts against the end face of the outer sheath base 8, the self-expanding support 11 extends completely beyond the end of the outer sheath body. The sheath core 15 is a flexible flexible tube, comprising a sheath core body 3, with a sheath core base 10 located near the proximal end of the sheath core body 3. The distal end of the sheath core body has a tapered end with a gradually decreasing outer diameter. A central hole for a guide wire is provided inside the sheath core body. The length of the sheath core is greater than that of the inner sheath. An inflatable balloon is provided at the front end of the guide wire. A hemostatic device 13 is detachably connected to the proximal end of the inner sheath base 9. For example... Figure 3 As shown, the hemostatic device 13 includes a hemostatic valve 4, which is connected to a three-way valve 6 via an extension tube 5. The three-way valve 6 has three openings, and in addition to the opening connected to the extension tube, the other two openings are equipped with protective caps 7.

[0051] The self-expanding stent 11 has a mesh structure and is a self-expanding covered stent. Both the inner and outer walls of the self-expanding stent 11 are provided with elastic covering layers to prevent scratching of the blood vessel wall. The self-expanding stent 11 is firmly connected to the distal end of the inner sheath body 2, and the connection position between the self-expanding stent 11 and the inner sheath body 2 has a tapered transition.

[0052] The outer sheath has an outer diameter of 5F-18F and a length of 20-110cm; the inner sheath has an outer diameter of 4F-16F and a length of 30-120cm; the sheath core has a length of 40-140cm. The self-expanding support has a diameter of 3mm-12mm and a length of 4mm-20mm after expansion.

[0053] This device, combined with the Fogarty balloon minimally invasive thrombectomy technique, allows for the placement of a variable-diameter vascular sheath into the blood vessel. Figure 4 As shown: S11: First, insert the guidewire along the vessel's course through the puncture site to the distal end of the thrombus; S12: Push the outer sheath, inner sheath, and sheath core together along the guidewire to the proximal end of the thrombus; S13: Retract the sheath core, and position the outer and inner sheaths appropriately along the guidewire; S14: Keep the inner sheath in a fixed position, retract the outer sheath so that the self-expanding inner sheath stent is partially or completely uncovered by the outer sheath, achieving self-expansion and adhering to the vessel wall. During this process, if the inner sheath is deemed incorrectly positioned, the outer sheath can be pushed forward to cover the self-expanding inner sheath stent, compressing the self-expanding inner sheath stent into the outer sheath, thereby adjusting the positions of the inner and outer sheaths; S15: Push the Fogarty thrombectomy balloon along the guidewire through the hollow channel inside the inner sheath to the distal end of the thrombus; S16: Expand the Fogarty thrombectomy balloon to adhere to the vessel wall. At this point, the thrombus is located between the self-expanding inner sheath stent and the Fogarty thrombectomy balloon.

[0054] This device utilizes a Fogarty balloon-assisted minimally invasive thrombectomy procedure with a variable-diameter vascular sheath, as follows: Figure 5 As shown: S21: The thrombus is located between the inner sheath self-expanding stent and the Fogarty thrombectomy balloon; S22: Retract the Fogarty thrombectomy balloon, pulling the thrombus into the inner sheath self-expanding stent; S23: Continue retraction and adjust the size of the Fogarty thrombectomy balloon to retract the balloon along with the thrombus into the inner sheath body; S24: Continue retraction of the Fogarty thrombectomy balloon; S25: Separate the connection between the inner sheath base and the hemostatic valve, and remove the thrombus and Fogarty thrombectomy balloon through the proximal end of the inner sheath body; S26: Push the outer sheath forward so that it partially covers the inner sheath self-expanding stent, restore forward blood flow, and inject contrast agent for angiography to observe for residual thrombus and other vascular lesions (dissection, stenosis, etc.). The thrombectomy process can be repeated to ensure complete removal of the thrombus. This vascular sheath can be used for subsequent interventional procedures such as stent implantation.

Claims

1. A variable-diameter vascular sheath structure, characterized in that: The structure consists of an outer sheath, an inner sheath, and a sheath core nested from the outside in. The outer sheath is a hollow flexible tube open at both ends, comprising an outer sheath body and an outer sheath base located near the proximal end of the outer sheath body. The inner sheath is also a hollow flexible tube open at both ends, comprising an inner sheath body, with an inner sheath base located near the proximal end of the inner sheath body. The distal end of the inner sheath body is connected to a self-expanding support open at both ends. The length of the inner sheath is greater than that of the outer sheath. The sheath core is a flexible flexible tube, comprising a sheath core body, with a sheath core base located near the proximal end of the sheath core body. The distal end of the sheath core body has a tapered end with a gradually decreasing outer diameter. The sheath core body has a central hole through which a guidewire passes. The length of the sheath core is greater than that of the inner sheath. The front end of the guidewire has an inflatable balloon.

2. The variable diameter vascular sheath structure according to claim 1, characterized in that: The self-expanding support has a mesh structure.

3. The variable diameter vascular sheath structure according to claim 1, characterized in that: The self-expanding stent is a self-expanding covered stent, and both the inner and outer walls of the self-expanding stent are provided with elastic covered layers to prevent scratching the blood vessel wall.

4. The variable diameter vascular sheath structure according to claim 1, characterized in that: The connection between the self-expanding support and the inner sheath body has a tapered transition.

5. A variable-diameter vascular sheath structure according to claim 1, characterized in that: When the inner sheath base abuts against the end face of the outer sheath base, the self-expanding support extends completely out of the end of the outer sheath body.

6. The variable diameter vascular sheath structure according to claim 1, characterized in that: The proximal end of the inner sheath base is detachably connected to a hemostatic valve, which is connected to a three-way valve via an extension tube.

7. A variable-diameter vascular sheath structure according to claim 6, characterized in that: The three-way valve has three openings. In addition to the opening that connects to the extension pipe, the other two openings are equipped with protective caps.

8. The variable diameter vascular sheath structure according to claim 1, characterized in that: The outer sheath has an outer diameter of 5F-18F and a length of 20-110cm; the inner sheath has an outer diameter of 4F-16F and a length of 30-120cm; and the sheath core has a length of 40-140cm.

9. A variable-diameter vascular sheath structure according to claim 8, characterized in that: The self-expanding support is firmly connected to the distal end of the inner sheath body. After expansion, the diameter of the self-expanding support is 3mm-12mm and the length is 4mm-20mm.

Images