CN115337074A

CN115337074A - Pulmonary artery embolism taking device with blood flow conduction function

Info

Publication number: CN115337074A
Application number: CN202110528981.7A
Authority: CN
Inventors: 王盛章; 赵可佳; 蔡云寒
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2021-05-14
Filing date: 2021-05-14
Publication date: 2022-11-15

Abstract

The invention relates to a pulmonary artery embolism extraction device with blood flow conduction function, which comprises: the expandable and contractible braided stent (1), the braided stent (1) is processed by shape memory alloy and is used for capturing thrombus and conducting blood flow; a delivery sheath (5) for constraining the retraction and release of the braided stent (1); a pushing circular tube (4) with a hollow structure, which is used for conveying the braided stent (1); the pushing circular tube (4) penetrates through the woven support (1) and penetrates through the whole thrombus taking device; when the braided stent (1) is expanded, the braided stent comprises at least two umbrella-shaped structures. Compared with the prior art, the thrombus extraction device provided by the invention can quickly reconstruct blood flow and realize the function of blood flow guidance, thereby relieving pulmonary embolism; and can catch the thrombus with high efficiency, take out the thrombus thoroughly, and greatly reduced the damage to the vascular wall, have good security and reliability.

Description

Pulmonary artery embolism taking device with blood flow conduction function

Technical Field

The invention relates to the field of medical instruments, in particular to a pulmonary artery embolism removal device with a blood flow conduction function.

Background

Blood components form blood clots in the circulation called thrombi. The uncompleted thrombus sloughs off, is carried by the blood stream to other locations in the circulatory system, and plugging some or all of the vessel lumen leads to thromboembolism. Damage to the vessel wall (mechanical, infectious, chemical, immunological, etc., factors), changes in blood composition, and changes in the state of blood flow (slowness, stagnation, vortex formation, etc.) are fundamental causes of thrombus formation. The blood vessel may be blocked to cause organ injury after the thrombus falls off due to external pressure, muscle contraction or catheter insertion. The thromboembolism may be of any size, and thromboembolic events may occur at any time.

When a thrombus forms in the venous circulation of the human body, it usually embolises the lungs. Such thrombi usually embolize from the veins of the leg, pelvis or inferior vena cava, travel to the right heart cavity and then into the pulmonary artery, resulting in pulmonary embolism. Pulmonary embolism can lead to right heart failure and reduce blood flow through the lungs, which in turn reduces oxygenation of the lungs, heart and other parts of the body. More specifically, when such a thrombus enters a pulmonary artery, obstruction and spasm of the different arteries of the lung occurs, which further reduces blood flow and gas exchange through the lung tissue, resulting in pulmonary edema. All of these factors reduce oxygen in the blood of the left heart. As a result, the oxygenated blood supplied by the coronary arteries to the muscles of the left and right heart is insufficient to cause the muscles to contract properly, which further reduces the overall flow of oxygenated blood to other parts of the body. This often leads to cardiac dysfunction, particularly right ventricular dysfunction.

There are many reasons for this. There is often a long period of inactivity, such as bed rest, sitting for a long period of time (e.g., long travel by airplane), dehydration, frequent surgery or long-term illness. Almost all of these causes are characterized by the fact that blood in the peripheral major circulatory system of the lower extremities coagulates to varying degrees and causes permanent drainage problems.

Over the past 20 years, the FDA has approved nearly 200 thrombectomy platforms developed for the arterial system. Thrombus research on the venous system is rare, and earlier products mainly apply artery-related products directly to veins. However, there are significant differences between the arterial and venous systems. The arterial system has high flow, high pressure characteristics, and thrombi in the arteries tend to be soft and concentrated and not connected to the vessel wall. But the situation of veins and arteries is quite the opposite, and the venous system has the characteristics of low flow and low pressure. Thus, the venous clot is slowly formed, which tends to grow slowly from the vessel wall. However, when the patient eventually presents to the emergency room, there is often already a large amount of blood clots, thousands of times larger than the arterial side, and often a chronic blood clot and an acute blood clot are simultaneously packed together. Therefore, antithrombotic drugs are often ineffective against venous thrombosis because they are chronic clots that are converted from fibers to collagen, requiring new interventional therapies to better address this disease.

There are many methods of treating thromboembolism, particularly pulmonary embolism. Some of these methods include the use of anticoagulants, thrombolytic agents and intravascular attempts to clear emboli from the pulmonary artery. Intravascular attempts to catheterize the affected vessel and chemical agents or by mechanical means to break down the clot. Invasive surgery removes emboli by accessing the chest cavity, opening the occluded pulmonary artery or branch thereof and removing the clot.

However, prior treatments have some drawbacks. For example, the use of agents such as anticoagulants or thrombolytic agents to reduce or eliminate pulmonary embolism often requires a long period of time, e.g., hours or even days, before treatment is effective. In certain instances, such drugs can cause bleeding in patients. In addition, the mechanical devices used to remove emboli are often highly complex, prone to undue trauma to the vessel, and can be difficult and expensive to manufacture.

Finally, once a thrombus is discovered, known treatments do not adequately address the goal of emergency restoration of blood flow through the thrombus and do not take into account the impact of blood flow on the thrombus during the embolectomy procedure. In other words, the known methods focus primarily and primarily on overall clot reduction and removal, rather than primarily on the mitigation of acute occlusion states, and do not take into account the impact of blood flow on thrombus during thrombus removal. Thus, the known methods do not provide optimal patient care, in particular because such care involves treatment of pulmonary emboli. Also, known mechanical devices for removing emboli are often very complex and prone to undue trauma to the vessel. Moreover, such known devices are difficult and expensive to manufacture.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a pulmonary artery embolism taking device which can quickly rebuild blood flow, conduct blood flow and capture and take out thrombus and has a blood flow conduction function.

The purpose of the invention can be realized by the following technical scheme:

in view of the foregoing, it is an object of the present invention to provide a device for minimally invasive interventional treatment of pulmonary embolism that first restores an acceptable level of oxygenated blood to the patient's circulatory system, performs blood flow guidance, and rapidly reestablishes blood flow without causing excessive damage to the blood vessels; then reducing the impact of blood flow on thrombus, capturing and removing the thrombus safely and effectively, and the specific scheme is as follows:

a pulmonary artery embolism thrombus removal device with blood flow communication function, which comprises:

an expandable and contractible braided stent, which is processed by shape memory alloy, has certain self-expansion capacity after heat setting, and forms a structure shown in figure 1 after being pressed, and a structure shown in figure 3 in a natural state for capturing thrombus and conducting blood flow;

the conveying sheath tube is used for restricting the retraction and the release of the braided stent;

the pushing circular tube is of a hollow structure and is used for conveying the braided stent;

the pushing circular tube penetrates through the weaving support and penetrates through the whole thrombus taking device, and the conveying sheath tube is sleeved outside the pushing circular tube; when the braided stent is withdrawn, the braided stent is abutted against the inner wall of the conveying sheath tube; when the braided stent is released, the conveying sheath tube releases the restraint on the braided stent;

when expanded, the braided stent comprises at least two umbrella structures.

The umbrella-shaped structure comprises an inclined plane, when the braided stent is pulled towards the near side, a force vertical to the inclined plane can be provided, one component pulls the thrombus towards the near side, and the other component is beneficial to separating the thrombus from the blood vessel without causing trauma to the blood vessel. The umbrella-shaped structures can be discontinuous or continuous and spiral on the pushing circular tube in a rotating stair type. "proximal" and "distal" refer to viewing from the physician, proximal referring to toward the physician, and distal referring to the side away from the physician.

Furthermore, in the umbrella-shaped structure, the inclination angle of the umbrella-shaped structure at the near end is smaller than that of the umbrella-shaped structure at the far end.

The action of clamping the thrombus to be captured increases the capturing capability of the thrombus. The umbrella-shaped structures are not limited to two stages, the middle of each stage of umbrella-shaped structure is connected by a drainage channel, and the conical direction of each umbrella-shaped structure can be towards the left or the right.

The inclination angle in the present invention means that the umbrella structure is assumed to be a planar structure perpendicular to the pushing circular tube, and the inclination angle means that the actual position of the umbrella structure forms an angle with the imaginary planar structure. In other words, the inclination angle of the planar structure perpendicular to the pushing circular tube is 0.

Further, the braided stent includes a dense portion and a loose portion;

the loose part is positioned at the proximal blood flow inlet and the distal blood flow outlet and is mainly used for guiding blood flow to flow into the blood flow channel;

the compact part is positioned in the middle part, and the most part of the compact part is positioned at the umbrella-shaped structure and mainly used as a blood flow channel for communicating blood flow.

The blood flow conduction function is realized mainly by the density change of the braided stent, the braided stent is sparse at the near end and the far end, and the middle section is encrypted. The membrane can be coated on the woven stent to better realize the drainage function.

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

Further, the far end of the pushing circular tube is fixedly provided with an attachment member for limiting the braided stent.

Further, the attaching component is a hollow structure, allows blood to flow out of the attaching component so as to allow blood to pass through, and is provided with a small hole for allowing a guide wire to pass through.

Further, the attachment member is made of a polymer material.

Furthermore, the near end of the braided support is connected with the pushing circular tube through a limiting spring. To limit axial displacement of the braided stent after expansion.

When the thrombus taking bracket is in a compressed state, the spring ring is in a natural state; when the stent is self-expanded, the spring ring is compressed.

Furthermore, a catheter is further sleeved outside the conveying sheath tube, the catheter, the conveying sheath tube and the pushing circular tube are coaxially arranged, and a guide wire is arranged at the axis.

It is not difficult to imagine that the pushing circular tube has a hollow structure, so that a guide wire can be allowed to pass through the pushing circular tube.

Furthermore, the braided stent is formed by braiding nickel-titanium alloy wires. But may also be replaced by a super hard material such as nitinol or a material such as cobalt chromium alloy.

The invention also provides a conveying method of the thrombus removal device.

After the guide wire reaches the position of the thrombus, the large-diameter catheter reaches the proximal end of the thrombus along the guide wire, the conveying sheath tube and the braided stent pass through the thrombus along the guide wire, then the conveying sheath tube is withdrawn, the braided stent gradually self-expands, the thrombus is attached to the umbrella-shaped and funnel-shaped structures, and the thrombus is captured. And finally, withdrawing the pushing circular tube, and recovering the braided stent and the thrombus into the large-diameter catheter.

Compared with the prior art, the invention has the following advantages:

(1) The thrombus taking device is used for mechanical thrombus taking of pulmonary artery, belongs to an intervention type mechanical thrombus taking device of pulmonary artery, and has small operation wound;

(2) The device changes the hemodynamics at the position of embolism by depending on the dense net weaving part, so that blood flows along the guiding device, and the blood flow guiding effect is realized; the braided stent delivered to the embolism position can immediately relieve acute embolism of a patient after self-expansion, and reduce the impact of blood flow on thrombus in the process of thrombus extraction, thereby preventing the embolism from fragmentation and escape;

(3) The umbrella-shaped design of the far end of the thrombus capture device increases the contact area of thrombus and the thrombus taking device, and the umbrella-shaped inclined plane is favorable for separating the thrombus from the wall surface of a blood vessel so as to capture the thrombus;

(4) The multi-stage conical structure with different angles is beneficial to capturing thrombus;

(5) The invention does not need to be equipped with an external power device, has low manufacturing cost and is beneficial to reducing the burden of patients.

Drawings

FIG. 1 is a schematic view of an embodiment of an embolectomy device passing through a thrombus;

FIG. 2 is a schematic view of the thrombus removal device in a fully self-expanded state in the embodiment;

FIG. 3 is a schematic view of the thrombus capture by the thrombectomy device in the embodiment

FIG. 4 is a side view of an attachment member of an embodiment;

the reference numbers in the figures indicate: the device comprises a braided stent 1, an attachment member 2, a limiting spring 3, a pushing circular tube 4, a conveying sheath tube 5, a catheter 6 and a guide wire 7.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

In the description of the present invention, the terms "proximal" and "distal" refer to the side from the doctor, proximal referring to the side toward the doctor, and distal referring to the side away from the doctor.

Examples

A pulmonary artery embolism retrieval device with blood flow communication function, as shown in fig. 1-3, the device comprises:

an expandable and contractible braided stent 1, wherein the braided stent 1 is processed by shape memory alloy, has certain self-expansion capability after heat setting, and forms a structure as shown in figure 1 after being pressed, and a structure as shown in figure 3 in a natural state for capturing thrombus and conducting blood flow;

a delivery sheath 5 for restricting the retraction and release of the braided stent 1;

a pushing circular tube 4 with a hollow structure for conveying the braided stent 1; is connected with the near end of the braided stent 1 through a limit spring 3;

the conveying sheath pipe 5 is sleeved outside the pushing circular pipe 4; when the braided stent 1 is withdrawn, the braided stent 1 is abutted against the inner wall of the conveying sheath tube 5; when the braided stent 1 is released, the braided stent 1 comprises at least two umbrella-shaped structures, and the conveying sheath 5 releases the restraint on the braided stent 1.

The conveying sheath pipe 5 is also sleeved with a guide pipe 6, the conveying sheath pipe 5 and the pushing circular pipe 4 are coaxially arranged, and a guide wire 7 is arranged at the axis. It is not inconceivable that the pushing cylinder 4 has a hollow structure, so that the guide wire 7 can pass through the hollow structure.

The umbrella-shaped structure comprises an inclined plane, when the braided stent 1 is pulled towards the near side, a force vertical to the inclined plane can be provided, one component of force pulls the thrombus towards the near side, and the other component of force is beneficial to separating the thrombus from the blood vessel without causing trauma to the blood vessel. The umbrella-shaped structures can be discontinuous or continuous, and spiral on the pushing circular tube 4 in a rotating stair type. In the umbrella-shaped structure, the inclination angle of the umbrella-shaped structure at the near end is smaller than that of the umbrella-shaped structure at the far end. The action of clamping the thrombus to be captured is formed, so that the capturing capability of the thrombus is increased. The umbrella-shaped structures are not limited to two stages, the middle of each stage of umbrella-shaped structure is connected by a drainage channel, and the conical direction of the umbrella-shaped structures can be towards the left or the right.

The braided stent 1 comprises a dense part and a loose part; the loose part is positioned at the near-end blood flow inlet and the far-end blood flow outlet and is mainly used for absorbing and capturing thrombus; the compact part is positioned in the middle part, and the most part is positioned at the umbrella-shaped structure generally and mainly used as a drainage channel for communicating blood flow. The blood flow conduction function is realized mainly by the density change of the braided stent 1, the braided stent is sparse at the near end and the far end, and the middle section is encrypted. The woven stent 1 can be coated with a film to better realize the drainage function. The pushing circular tube 4 can be provided with an opening for guiding blood flow to flow into a drainage channel formed by the braided stent 1.

As shown in fig. 3, the distal end of the pushing cylinder 4 is fixedly provided with an attachment member 2 for limiting the braided stent 1. The attachment member 2 is of an open construction allowing blood flow therethrough and is provided with a small hole allowing a guide wire 7 to pass therethrough. The attachment member 2 is made of a polymer material. The braided stent 1 is formed by braiding nitinol wires. But may also be replaced by a super hard material such as nitinol or a material such as cobalt chromium alloy.

The near end of the braided stent 1 is connected with a pushing circular tube 4 through a limiting spring 3. To limit axial displacement of the braided stent 1 after expansion. When the thrombus taking bracket is in a compressed state, the spring ring is in a natural state; when the stent is self-expanded, the spring ring is compressed.

The invention is used for the interventional pulmonary artery embolectomy, a large-caliber catheter 6 is inserted into the femoral vein of a patient, and then tools and devices required for treating pulmonary embolism are inserted into the femoral vein through the inferior vena cava and a guiding device and do not reach the heart of the patient. Access from other locations of the patient's venous circulatory system is also possible, allowing the length of the guide to be reduced. Such as via the jugular vein, the subclavian vein, the brachial artery vein or any other venous access that ultimately leads to the superior vena cava.

The thrombectomy device is then passed through the right atrium, across the tricuspid valve, into the right ventricle, and then across the pulmonary valve into the main pulmonary artery. After reaching the main pulmonary valve, the thrombus removal device is guided to the left pulmonary artery or the right pulmonary artery according to the position of the thrombus to reach the position of the thrombus.

After the guidewire 7 reaches the site of the embolism, the catheter large diameter catheter 6 is guided to the proximal embolism, the delivery sheath 5 is continuously guided forward to the distal end of the embolism, the attachment member 2 is completely passed through the thrombus portion, and then the delivery sheath 5 is withdrawn in the proximal direction, thereby exposing the thrombus capture device, which, due to its shape memory properties, expands the stent 1, blood can flow through the drainage channel, acute embolism is relieved, and the impact of blood flow on the embolism is prevented.

The pusher metal pusher tube 4 is then withdrawn, pulling the distal attachment member 2 proximally back, thereby withdrawing the entire thrombectomy device and the captured thrombi into the delivery sheath 5, withdrawing the entire delivery system from the patient.

Wherein, weave support 1 from the blood flow direction after the inflation completely as shown in figure 3, the blood flow weaves sparse part from the near-end and flows in the support in, and middle dense part can supply blood to flow for drainage channel, carries out the blood flow direction, and the blood flow recovers after the inflation, has alleviated acute embolism, has improved the circulation of the internal oxygenated blood of patient to prevent the impact of blood flow to the thrombus, the blood flow is followed and is attached the component 2 outflow.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A pulmonary artery embolism removal device with blood flow communication function is characterized by comprising:

the expandable and contractible braided stent (1), the braided stent (1) is processed by shape memory alloy and is used for capturing thrombus and conducting blood flow;

a delivery sheath (5) for constraining the retraction and release of the braided stent (1);

a pushing circular tube (4) with a hollow structure for conveying the braided stent (1);

the pushing circular tube (4) penetrates through the braided support (1) and penetrates through the whole thrombus removal device, and the conveying sheath tube (5) is sleeved outside the pushing circular tube (4); when the braided stent (1) is withdrawn, the braided stent (1) is abutted against the inner wall of the conveying sheath tube (5);

when the braided stent (1) is expanded, the braided stent comprises at least two umbrella-shaped structures.

2. The pulmonary artery embolectomy device of claim 1, wherein the proximal umbrella structure is inclined at an angle smaller than the distal umbrella structure.

3. The pulmonary artery embolism retrieval device with blood flow communication function as claimed in claim 1, wherein the braided stent (1) comprises a dense part and a loose part;

the loose part is positioned at the near end and the far end;

the dense part is located in the middle.

4. The pulmonary artery embolism removal device with the blood flow communication function as claimed in claim 1 or 3, wherein the pushing circular tube (4) is provided with an opening for guiding blood flow to the braided stent (1).

5. The pulmonary artery embolism retrieval device with blood flow communication function according to claim 1, wherein the distal end of the pushing circular tube (4) is fixedly provided with an attachment member (2) for limiting the braided stent (1).

6. The pulmonary artery embolism removal device with the blood flow communication function as claimed in claim 5, wherein the attachment member (2) is hollow and provided with a small hole.

7. The pulmonary artery embolectomy device with blood flow communication function of claim 5, wherein the attaching member (2) is made of polymer material.

8. The pulmonary artery embolism retrieval device with blood flow communication function as claimed in claim 1 or 5, wherein the proximal end of the braided stent (1) is connected with the pushing circular tube (4) through a limiting spring (3).

9. The pulmonary artery embolism extraction device with the blood flow communication function according to claim 1, wherein a catheter (6) is further sleeved outside the delivery sheath (5), the catheter (6), the delivery sheath (5) and the pushing circular tube (4) are coaxially arranged, and a guide wire (7) is arranged at the axial center.

10. The pulmonary artery embolism retrieval device with blood flow communication function as claimed in claim 1, wherein the braided stent (1) is braided by nitinol wires.