A pulmonary artery embolism thrombectomy device with blood flow conduction function

Abstract

The present invention relates to a pulmonary embolism thrombus removal device with a blood flow conduction function, the device comprising: an expandable and contractible braided stent (1), the braided stent (1) being made of a shape memory alloy and being used to capture thrombi and conduct blood flow; a delivery sheath (5) being used to constrain the withdrawal and release of the braided stent (1); a hollow push tube (4) being used to deliver the braided stent (1); the push tube (4) being arranged in the braided stent (1) and running through the entire thrombus removal device; the braided stent (1) comprising at least two umbrella-shaped structures when expanded. Compared with the prior art, the thrombus removal device provided by the present invention can quickly reestablish blood flow, realize the blood flow conduction function, and thus alleviate pulmonary embolism; and can efficiently capture thrombi, completely remove thrombi, and greatly reduce damage to the blood vessel wall, thereby having good safety and reliability.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a pulmonary embolism thrombectomy device with a blood flow conduction function. Background Art

[0002] The formation of blood clots within the circulation is called a thrombus. If an unorganized thrombus breaks off and is carried by the bloodstream to other locations in the circulatory system, blocking part or all of the blood vessel lumen, it can lead to thromboembolism. Damage to the blood vessel wall (mechanical, infectious, chemical, immune, etc.), changes in blood composition, and changes in blood flow (slowness, stagnation, vortex formation, etc.) are the basic causes of thrombosis. Dislodgment of a thrombus due to external pressure, muscle contraction, or catheterization can cause blood vessel blockage and organ damage. Thromboemboli can be of any size, and thromboembolic events can occur at any time.

[0003] When a blood clot forms in the body's venous circulation, it often travels to the lungs. Such clots typically invade the veins of the legs, pelvis, or inferior vena cava, travel to the right heart chamber, and then into the pulmonary arteries, resulting in pulmonary embolism. Pulmonary embolism can lead to right-sided heart failure and reduce blood flow to the lungs, which in turn reduces oxygenation in the lungs, heart, and other parts of the body. More specifically, when such a clot enters the pulmonary artery, it can cause blockage and spasm of various pulmonary arteries, further reducing blood flow and gas exchange through the lung tissue, leading to pulmonary edema. All of these factors reduce the amount of oxygen in the blood flowing through the left side of the heart. As a result, the coronary arteries supply insufficient oxygenated blood to the muscles of the left and right heart for proper muscle contraction, further reducing the overall oxygenated blood flow to the rest of the body. This often leads to heart dysfunction, particularly right ventricular dysfunction.

[0004] There are many causes of this condition. Common ones include prolonged inactivity, such as bed rest, prolonged sitting (e.g., long airplane trips), dehydration, frequent surgery, or long-term illness. Almost all of these causes are characterized by varying degrees of clotting of the blood in the peripheral circulation of the lower extremities, leading to permanent drainage problems.

[0005] Over the past 20 years, the FDA has approved nearly 200 thrombectomy platforms developed for the arterial system. Research targeting venous thrombosis is limited, and early product development primarily involved applying arterial-specific products directly to veins. However, there are significant differences between the arterial and venous systems. Arterial clots are characterized by high flow and high pressure, so arterial clots are often soft and centralized, not attached to the vessel wall. The opposite is true for venous clots, which are characterized by low flow and low pressure. Consequently, venous clots form slowly, tending to grow from the vessel wall. However, by the time patients present to the emergency room, they often already have massive clots, thousands of times larger than those in the arterial area, and often a combination of chronic and acute clots. Consequently, antithrombotic drugs are often ineffective against venous clots, as these are chronic clots that transform from fibrils to collagen. New interventional therapies are needed to better manage these conditions.

[0006] There are many treatment options for thromboembolism, particularly pulmonary embolism. Some of these include the use of anticoagulants, thrombolytics, and endovascular attempts to remove the embolus from the pulmonary artery. Endovascular attempts involve inserting a catheter and chemical agents into the affected blood vessels or using mechanical methods to break up the clot. Invasive surgical procedures involve removing the embolus by entering the chest cavity, opening the blocked pulmonary artery or its branches, and removing the clot.

[0007] However, previous treatments have several drawbacks. For example, reducing or eliminating pulmonary embolism using agents such as anticoagulants or thrombolytics often takes a long time, often hours or even days, before treatment is effective. In some cases, such medications can cause bleeding in patients. Furthermore, the mechanical devices used to eliminate emboli are often highly complex, prone to undue trauma to blood vessels, and can be difficult and expensive to manufacture.

[0008] Finally, once a thrombus is identified, known treatments fail to adequately emphasize the goal of urgently restoring blood flow through the thrombus and fail to account for the impact of blood flow on the thrombus during thrombectomy. In other words, known methods primarily and primarily focus on overall clot reduction and removal, rather than primarily on alleviating the acute obstructive state, and fail to account for the impact of blood flow on the thrombus during thrombectomy. Consequently, known methods fail to provide optimal patient care, particularly as such care pertains to the treatment of pulmonary embolism. Furthermore, known mechanical devices for removing emboli are often highly complex and prone to undue trauma to the vessel. Furthermore, such known devices are difficult and expensive to manufacture. Summary of the Invention

[0009] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a pulmonary embolism thrombectomy device with blood flow conduction function that can quickly restore blood flow, conduct blood flow, and capture and remove thrombi.

[0010] The purpose of the present invention can be achieved by the following technical solutions:

[0011] In view of the foregoing, the present invention aims to provide a minimally invasive interventional treatment device for pulmonary embolism. This device first restores acceptable levels of oxygenated blood to the patient's circulatory system, directs blood flow, and rapidly reestablishes blood flow without causing excessive damage to the blood vessels. It then reduces the impact of blood flow on the thrombus, safely and effectively capturing and removing the thrombus. The specific approach is as follows:

[0012] A pulmonary artery embolism removal device with a blood flow conduction function, comprising:

[0013] The braided stent is expandable and contractible. It is made of shape memory alloy and has a certain self-expansion ability after heat setting. After being pressed, it forms a Figure 1 The structure shown in the natural state is as Figure 3 The structure in the lining is used to capture thrombi and redirect blood flow;

[0014] Delivery sheath, used to constrain the withdrawal and release of the braided stent;

[0015] A hollow push tube for delivering braided stents;

[0016] The pushing tube is inserted into the braided stent and runs through the entire thrombectomy device, and the delivery sheath is sleeved outside the pushing tube; when the braided stent is retracted, the braided stent abuts against the inner wall of the delivery sheath; when the braided stent is released, the delivery sheath releases the constraint on the braided stent;

[0017] When the braided stent is expanded, it includes at least two umbrella-shaped structures.

[0018] The umbrella-like structure includes an inclined surface. When the braided stent is pulled proximally, it provides a force perpendicular to the inclined surface. One component of the force pulls the thrombus proximally, while the other component helps separate the thrombus from the vessel without causing trauma to the vessel. The umbrella-like structure can be intermittent or continuous, spiraling around the push tube like a spiral staircase. "Proximal" and "distal" refer to the direction of the surgeon, with proximal referring to the side toward the surgeon and distal referring to the side away from the surgeon.

[0019] Furthermore, in the umbrella-like structure, the inclination angle of the umbrella-like structure at the proximal end is smaller than the inclination angle of the umbrella-like structure at the distal end.

[0020] The captured thrombus is clamped, thereby increasing the ability to capture the thrombus. The umbrella-shaped structure is not limited to two levels, and each level of the umbrella-shaped structure is connected by a drainage channel in the middle. The cone direction of the umbrella-shaped structure can be left or right.

[0021] The so-called tilt angle in the present invention refers to the angle between the actual position of the umbrella-shaped structure and the imaginary plane structure, assuming that the umbrella-shaped structure is a plane structure perpendicular to the push tube. In other words, the tilt angle of the plane structure perpendicular to the push tube is 0.

[0022] Furthermore, the braided stent comprises a dense portion and a loose portion;

[0023] The loose portion is located at the proximal blood flow inlet and the distal blood flow outlet, and is mainly used to guide blood flow into the blood flow channel;

[0024] The dense part is located in the middle, and most of it is generally located in the umbrella-shaped structure, which mainly serves as a blood flow channel to conduct blood flow.

[0025] Blood flow conduction is primarily achieved through variations in the density of the braided stent, which is sparse at the proximal and distal ends and dense in the middle. Coatings can also be applied to the braided stent to further enhance drainage.

[0026] Furthermore, the pushing circular tube is provided with an opening for better guiding blood flow into the drainage channel formed by the braided stent.

[0027] Furthermore, an attachment component is fixed to the distal end of the pushing circular tube for limiting the position of the braided stent.

[0028] Furthermore, the attachment member is a hollow structure, allowing blood to flow out of it to allow blood to pass through it, and is provided with a small hole allowing the guide wire to pass through it.

[0029] Furthermore, the attachment member is made of polymer material.

[0030] Furthermore, the proximal end of the braided stent is connected to the pushing circular tube via a limit spring, which is used to limit the axial displacement of the braided stent after expansion.

[0031] When the thrombectomy stent is in a compressed state, the spring coil is in a natural state; when the thrombectomy stent expands itself, the spring coil is compressed.

[0032] Furthermore, a catheter is sheathed outside the delivery sheath, and the catheter, delivery sheath and pushing tube are coaxially arranged, and a guide wire is provided at the axis.

[0033] It is not difficult to imagine that since the push tube is a hollow structure, it allows the guide wire to pass through it.

[0034] Furthermore, the braided stent is braided from nickel-titanium alloy wires, and may also be replaced by superhard materials such as nitinol or materials such as cobalt-chromium alloys.

[0035] The present invention also provides a method for delivering the thrombus removal device.

[0036] After the guidewire reaches the thrombus, the large-diameter catheter follows the guidewire to the proximal end of the thrombus. The delivery sheath and braided stent follow the guidewire through the thrombus. The delivery sheath is then withdrawn, and the braided stent gradually self-expands, trapping the thrombus by attaching to the umbrella-shaped and funnel-shaped structures. Finally, the push tube is withdrawn, and the braided stent and thrombus are retrieved and returned to the large-diameter catheter.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] (1) The thrombectomy device of the present invention is used for mechanical thrombectomy of the pulmonary artery and is an interventional pulmonary artery mechanical thrombectomy device with a small surgical wound.

[0039] (2) The device of the present invention relies on the densely woven mesh portion to change the hemodynamics at the embolic site, allowing the blood to flow along the guide device, thereby achieving the function of blood flow guidance; after being delivered to the embolic site, the braided stent self-expands, which can immediately relieve the patient's acute embolism, and reduce the impact of blood flow on the thrombus during thrombectomy, preventing the embolus from breaking and escaping;

[0040] (3) The umbrella-shaped design of the distal end of the present invention increases the contact area between the thrombus and the thrombus remover, and the umbrella-shaped slope facilitates the separation of the thrombus from the vessel wall, thereby capturing the thrombus;

[0041] (4) The multi-level tapered structure of the present invention with different angles is conducive to the capture of thrombus;

[0042] (5) The present invention does not require an external power device, has a low cost, and is beneficial for reducing the burden on patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the thrombus removal device passing through the thrombus in the embodiment;

[0044] Figure 2 is a schematic diagram of the thrombus removal device in a fully self-expanding state according to an embodiment;

[0045] Figure 3 Schematic diagram of a thrombus removal device capturing a thrombus in an embodiment

[0046] Figure 4 A side view of an attachment member in an embodiment;

[0047] The numbers in the figure indicate: braided stent 1, attachment member 2, limit spring 3, push tube 4, delivery sheath 5, catheter 6, guide wire 7. DETAILED DESCRIPTION

[0048] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0049] In the description of the present invention, the terms "proximal end" and "distal end" refer to the side viewed from the doctor's direction, the proximal end means toward the doctor, and the distal end means the side away from the doctor.

[0050] Example

[0051] A pulmonary artery embolism removal device with blood flow conduction function, such as Figure 1-3 , the device comprises:

[0052] The braided stent 1 is expandable and contractible. The braided stent 1 is made of shape memory alloy and has a certain self-expansion ability after heat setting. After being pressed, it forms a Figure 1 The structure shown in the natural state is as Figure 3 The structure in the lining is used to capture thrombi and redirect blood flow;

[0053] The delivery sheath 5 is used to constrain the withdrawal and release of the braided stent 1;

[0054] The hollow push tube 4 is used to transport the braided stent 1 and is connected to the proximal end of the braided stent 1 via a limit spring 3;

[0055] The delivery sheath 5 is sleeved on the outside of the pushing circular tube 4; when the braided stent 1 is retracted, the braided stent 1 abuts against the inner wall of the delivery sheath 5; when the braided stent 1 is released, it includes at least two umbrella-shaped structures, and the delivery sheath 5 releases the constraint on the braided stent 1.

[0056] The delivery sheath 5 is also sheathed with a catheter 6, which is coaxially arranged with the delivery sheath 5 and the push tube 4, and a guide wire 7 is provided at the axis. It is not difficult to imagine that since the push tube 4 is a hollow structure, the guide wire 7 can be allowed to pass therethrough.

[0057] The umbrella-shaped structure includes an inclined plane. When the braided stent 1 is pulled proximally, it can provide a force perpendicular to the inclined plane. One component of the force pulls the thrombus proximally, and the other component of the force is conducive to the separation of the thrombus from the blood vessel without causing trauma to the blood vessel. The umbrella-shaped structures can be intermittent or continuous, and are spirally wound on the pushing tube 4 in the form of a spiral staircase. In the umbrella-shaped structure, the inclination angle of the proximal umbrella-shaped structure is smaller than the inclination angle of the distal umbrella-shaped structure. A clamping action is formed on the thrombus to be captured, thereby increasing the ability to capture the thrombus. The umbrella-shaped structure is not limited to two levels. The umbrella-shaped structures at each level are connected by a drainage channel in the middle, and the tapered direction of the umbrella-shaped structure can be left or right.

[0058] The braided stent 1 includes a dense portion and a loose portion; the loose portion is located at the proximal blood flow inlet and distal blood flow outlet, and is primarily used to absorb and capture thrombi; the dense portion is located in the middle, generally mostly located in the umbrella-shaped structure, and primarily serves as a drainage channel to conduct blood flow. The blood flow conduction function is primarily achieved by varying the density of the braided stent 1, which is sparse at the proximal and distal ends and dense in the middle section. The braided stent 1 can also be coated to further achieve the drainage function. The push tube 4 can be provided with an opening to guide blood flow into the drainage channel formed by the braided stent 1.

[0059] like Figure 3 The distal end of the push tube 4 is secured with an attachment member 2, which serves to position the braided stent 1. The attachment member 2 is a hollow structure that allows blood to flow out and has a small hole for the passage of the guidewire 7. The attachment member 2 is made of a polymer material. The braided stent 1 is braided from nickel-titanium alloy wire. It can also be substituted with ultra-hard materials such as nitinol or cobalt-chromium alloy.

[0060] The proximal end of the braided stent 1 is connected to the push tube 4 via a limit spring 3, which is used to limit the axial displacement of the braided stent 1 after expansion. When the thrombectomy stent is in a compressed state, the spring coil is in a natural state; when the thrombectomy stent expands, the spring coil is compressed.

[0061] The present invention is used for interventional pulmonary artery thrombectomy. A large-caliber catheter 6 is inserted into the patient's femoral vein. The tools and devices required for treating pulmonary embolism are then inserted through the inferior vena cava via an introducer into the femoral vein, reaching the patient's heart. Access from other locations within the patient's venous system is also feasible, reducing the length of the introducer. For example, access can be made through the jugular vein, subclavian vein, brachial artery, or any other vein that ultimately leads to the superior vena cava.

[0062] The thrombectomy device is then passed through the right atrium, across the tricuspid valve, into the right ventricle, and then through the pulmonary valve into the main pulmonary artery. Once at the main pulmonary valve, the thrombectomy device is guided to the left or right pulmonary artery, depending on the location of the embolism.

[0063] After the guide wire 7 reaches the location of the embolism, the large-caliber catheter 6 is guided to the proximal embolism, and the delivery sheath 5 is further guided forward to the distal end of the embolism, so that the attachment member 2 completely passes through the thrombus part, and then the delivery sheath 5 is withdrawn in the proximal direction to expose the thrombus capture device. Due to its shape memory characteristics, the thrombus capture device braided stent 1 expands, and blood can flow through the drainage channel, acute embolism is alleviated, and the impact of blood flow on the embolism is prevented.

[0064] Then, the metal push tube 4 is retracted and pushed, and the distal attachment member 2 is pulled proximally to be recovered, so that the entire thrombus removal device and the captured thrombus are recovered into the delivery sheath 5, and the entire delivery system is withdrawn from the patient's body.

[0065] Wherein, after the braided stent 1 is fully self-expanded, the blood flow direction is as follows: Figure 3 As shown, blood flows from the sparsely woven part at the proximal end into the stent, and the dense part in the middle is a drainage channel for blood flow and blood flow guidance. After expansion, blood flow is restored, which relieves acute embolism, improves the circulation of oxygenated blood in the patient's body, and prevents the impact of blood flow on thrombus. Blood flows out from the attachment member 2.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A pulmonary artery embolism removal device with blood flow conduction function, characterized in that: The device includes: An expandable and contractible braided stent (1) is made of a shape memory alloy and is used to capture thrombi and conduct blood flow; the braided stent (1) comprises a dense portion and a loose portion; the loose portion is located at the proximal end and the distal end, and the dense portion is located in the middle; the "proximal end" and "distal end" refer to the side viewed from the doctor's direction, the proximal end refers to the side facing the doctor, and the distal end refers to the side away from the doctor; A delivery sheath (5) is used to constrain the withdrawal and release of the braided stent (1); A hollow push tube (4) is used to transport the braided stent (1); an opening is provided on the push tube (4) for guiding blood flow into the braided stent (1); the proximal end of the braided stent (1) is connected to the push tube (4) via a limit spring (3); the push tube (4) is inserted into the braided stent (1) and passes through the entire thrombus removal device, and the delivery sheath (5) is sleeved outside the push tube (4); when the braided stent (1) is withdrawn, the braided stent (1) abuts against the inner wall of the delivery sheath (5); an attachment member (2) is fixed to the distal end of the push tube (4) for limiting the position of the braided stent (1); the attachment member (2) is a hollow structure and is provided with a small hole; The delivery sheath (5) is further provided with a catheter (6), the catheter (6), the delivery sheath (5) and the pushing tube (4) are coaxially arranged, and a guide wire (7) is provided at the axis; When the braided stent (1) is expanded, it comprises at least two umbrella-shaped structures; among the umbrella-shaped structures, the inclination angle of the umbrella-shaped structure at the proximal end is smaller than the inclination angle of the umbrella-shaped structure at the distal end.

2. The pulmonary artery embolism thrombus removal device with blood flow conduction function according to claim 1, characterized in that: The attachment member (2) is made of polymer material.

3. The pulmonary artery embolism removal device with blood flow conduction function according to claim 1, characterized in that: The braided stent (1) is braided and formed from nickel-titanium alloy wires.

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