Intracranial suction catheter and method of use thereof

Abstract

The present invention discloses an intracranial suction catheter and a method for using the same, comprising: a catheter body and a handle connected to the catheter body; the catheter body comprises a push tube connected to the catheter body, a catheter proximal expansion portion arranged on one end of the catheter body close to the push tube direction, a proximal development ring arranged between the catheter proximal expansion portion and the catheter body, and a distal development ring arranged at the other end of the catheter body; the catheter proximal expansion portion comprises a braided mesh inner layer and a braided mesh outer layer, and the opening section in the catheter proximal expansion portion is a trumpet-shaped structure with an oblique opening; the method for using the catheter is to tighten the closing ring when the catheter enters the sheath, and after the catheter is in place, the opening section is gradually expanded to fit the inner wall of the sheath, and a suction power source is added at the proximal end of the sheath to complete the suction of the thrombus. Under the condition that the suction source provides the same suction force, the present invention increases the cross-sectional area for obtaining the suction force and improves the suction efficiency by connecting the suction power source to a new suction method of a long sheath.

Description

Technical Field

[0001] The present invention relates to the technical field of surgical supplies materials, in particular to the technical field of anticoagulation treatment of surgical supplies, and specifically to an intracranial suction catheter and a method for using the same. Background Art

[0002] Ischemic stroke is a general term for brain tissue necrosis caused by stenosis or occlusion of the blood supply arteries to the brain and insufficient blood supply to the brain. Ischemic stroke has now become a common cerebrovascular disease, and its cause is mostly due to poor blood flow caused by blockage of intracranial blood vessels. The most common cause of cerebral thrombosis is atherosclerosis of the intracranial arteries, which leads to thickening of the vascular endothelium and narrowing of the vascular lumen. At the narrow part of the blood vessel, coagulation factors may coagulate into blocks in the blood vessel to form a thrombus due to factors such as increased blood viscosity, reduced vascular pressure and flow rate, and platelet aggregation. Thrombi in the blood vessels will cause blood vessel blockage, greatly reducing blood flow, and even completely blocking the blood vessels in severe cases. If the brain tissue cannot be supplied with sufficient blood normally for a long time, severe cases may eventually lead to brain tissue necrosis.

[0003] For the treatment of cerebral thrombosis, a suction catheter is usually used to aspirate and remove the thrombus at the lesion. Compared with the stent thrombectomy method, the use of a suction catheter thrombectomy has the advantages of preventing the thrombus from breaking during the thrombectomy process and shortening the recanalization time.

[0004] Traditional suction catheters will produce coagulation when in use. This is because after blood is exposed to the catheter surface, blood components (such as proteins and platelets) will quickly adsorb to the catheter surface, causing platelet aggregation and activation of coagulation factors, thereby triggering a coagulation cascade reaction, which may lead to the formation of blood clots.

[0005] Therefore, bioactive coatings such as heparin coatings are used, which inhibit the activity of coagulation factors by binding and activating antithrombin III (ATIII) in the blood, thereby blocking the coagulation reaction. However, after the heparin coating is fixed on the surface of the polymer material, its biological activity may be reduced.

[0006] Moreover, the use of traditional suction catheters is usually accompanied by a long sheath to enter the blood circuit. The distal tip of the suction catheter is close to the thrombus, and negative pressure is applied at the proximal end to suck the thrombus from the distal port of the suction catheter into the tube body and expel it from the body. The suction efficiency of the suction catheter is proportional to the suction force applied to the catheter and the inner diameter of the catheter. Therefore, under the condition of a constant suction force, increasing the inner diameter of the catheter can significantly improve the suction efficiency of the catheter. The suction process of the traditional suction catheter is completely carried out inside the suction catheter. However, due to the size limitation of the long sheath, the extent to which the inner diameter of the suction catheter can be increased is very limited, resulting in insufficient improvement in suction efficiency, and the efficiency and success rate of thrombectomy are still very low.

[0007] Therefore, it is necessary to provide an intracranial aspiration catheter with high aspiration rate, high thrombus removal rate and high anticoagulant performance to solve the above problems. Summary of the invention

[0008] The present invention overcomes the deficiencies of the prior art and provides an intracranial suction catheter and a method for using the same.

[0009] To achieve the above object, the technical solution adopted by the present invention is: an intracranial suction catheter, comprising: a catheter body, and a handle connected to the catheter body;

[0010] The catheter body comprises: a catheter body, a push tube connected to the catheter body, a catheter proximal expansion portion arranged at one end of the catheter body close to the push tube, a proximal development ring arranged between the catheter proximal expansion portion and the catheter body, and a distal development ring arranged at the other end of the catheter body;

[0011] The proximal expansion portion of the catheter is a double-layer braided mesh structure, including a braided mesh inner layer and a braided mesh outer layer. The proximal expansion portion of the catheter includes an opening section and a transition section. The opening section is a trumpet-shaped structure and is an oblique opening.

[0012] A cross-closing ring is arranged at the bottom of the proximal expansion part of the catheter, and the closing ring is divided into a supporting part and a connecting part. The supporting part is arranged between the inner layer of the braided mesh and the outer layer of the braided mesh. A plurality of recovery wires are arranged in the push tube, and the connecting part extends to the recovery wire inside the push tube through two side holes opened on the push tube; one end of the recovery wire is connected to the handle, and the other end is welded to the end of the connecting part of the closing ring.

[0013] In a preferred embodiment of the present invention, the tube body structure of the catheter tube body is, from inside to outside, a PTFE film layer, a metal reinforcement layer, a polymer material outer layer and a hydrophilic coating, wherein the metal reinforcement layer is a double-layer structure formed by combining a braided layer and a spring layer, the braided layer is arranged on the outer layer, and the spring layer is arranged on the inner layer.

[0014] In a preferred embodiment of the present invention, the total length of the catheter body is 30 to 50 cm, and 5 to 10 cm of the catheter body away from one end of the push tube is configured as a single-layer spring-wound non-woven structure.

[0015] In a preferred embodiment of the present invention, the inner diameter and outer diameter of the catheter tube body are one of the following specifications: inner diameter 1.4 mm, outer diameter 1.7 mm (5F) or inner diameter 1.8 mm, outer diameter 2.1 mm (6F).

[0016] In a preferred embodiment of the present invention, the total length of the push tube is 90 to 110 cm, and one end close to the catheter body is a hypotube structure, and the length of the hypotube structure is 1 / 2 to 1 / 3 of the total length of the push tube.

[0017] In a preferred embodiment of the present invention, the proximal developing ring is arranged on the braided layer of the catheter tube body by welding; the distal developing ring is arranged on the single-layer spring-wound non-braided structure of the distal end of the catheter tube body by welding; wherein the developing ring is made of a platinum group metal alloy.

[0018] In a preferred embodiment of the present invention, the closing ring is woven from a plurality of metal braided wire strands, the number of the metal braided wire strands is 4 to 10 strands, of which 2 to 4 strands are braided wires of developing material, and the rest are nickel-titanium wires.

[0019] In a preferred embodiment of the present invention, the average weaving pore size of the opening section is 60-80 μm, the transition section is a mesh tube structure, and the average weaving pore size of the transition section is 30-40 μm.

[0020] In a preferred embodiment of the present invention, the opening section and the transition section are both woven from nickel-titanium wires that have been subjected to a heat treatment and shaping process, and the number of nickel-titanium wire strands is 48 to 64.

[0021] The present invention also provides a method for using an intracranial suction catheter, comprising the following steps:

[0022] S1. After the long sheath of the suction catheter reaches the position, insert the suction catheter along the long sheath;

[0023] S2. When the suction catheter enters the sheath, tighten the closing ring by pulling back the handle to ensure that the proximal expansion part of the catheter is in a tightened state;

[0024] S3, after the suction catheter enters the sheath and reaches the suction position, the handle is released to gradually expand the trumpet-shaped structure of the opening section of the proximal expansion part of the catheter as the closing ring is released until it fits with the inner wall of the sheath; and the opening and closing of the opening section is observed at any time through the display image;

[0025] S4. After the suction catheter is stabilized, add a suction power source at the proximal end of the sheath to complete the suction of the thrombus.

[0026] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0027] (1) The present invention provides an intracranial suction catheter and a method for using the same suction force provided by the suction source. By adopting a new suction method in which the suction power source is connected to a long sheath, the cross-sectional area of ​​the proximal end of the suction catheter for obtaining the suction force is increased, thereby solving the problem in the prior art that the inner diameter of the suction catheter is limited due to the size limitation of the long sheath, thereby improving the suction efficiency. At the same time, the anti-coagulant coating can reduce the coagulation reaction when the catheter surface contacts the blood, and reduce the formation of thrombus on the catheter surface. The anti-coagulant coating has good biocompatibility and lubricity, which can reduce the friction and damage between the catheter and the blood vessel wall, thereby protecting the integrity of the blood vessel wall and improving the safety of the operation.

[0028] (2) The present invention uses a double-layer braided mesh structure for the catheter proximal expansion portion, which can well maintain the shape and expandability of the proximal end of the catheter. At the same time, the opening section is designed as a trumpet-shaped structure with an oblique opening, which is conducive to attracting thrombus into the interior of the catheter. At the same time, it can further improve the adhesion between the proximal end of the suction catheter and the inner wall of the long sheath, thereby avoiding the loss of suction force in the suction catheter.

[0029] (3) The catheter body of the present invention adopts a multi-layer composite structure, with different materials arranged in the inner and outer layers, which can well ensure the mechanical strength, radiopacity and biocompatibility of the catheter; at the same time, by setting proximal and distal developing rings, it is convenient to observe the position and condition of the catheter during imaging examinations such as CT.

[0030] (4) The present invention tightens the closing ring by pulling back the handle first, thereby ensuring that the proximal expansion portion is in a tightened state. Before the suction catheter enters the long sheath, the proximal expansion portion can be tightened by tightening the closing ring, thereby effectively reducing the diameter of the catheter, making it easier for it to pass through the narrow channel of the long sheath, and maintaining the stability and smoothness of the catheter during the process of the suction catheter entering the long sheath; at the same time, it helps to avoid excessive friction and resistance between the catheter and the inner wall of the long sheath during the pushing process, thereby improving the passability and pushing efficiency of the catheter.

[0031] (5) The tightening ring of the present invention can make the catheter more stable during the pushing process. Due to the supporting effect of the long sheath, the tightened proximal expansion part can better fit the inner wall of the long sheath, reducing the radial runout and deviation of the catheter; it helps to improve the controllability and accuracy of the catheter, and can more accurately control the position and direction of the catheter.

[0032] (6) The flow rate slowing zone designed in the present invention can gradually reduce the blood flow rate in the catheter, and can achieve preliminary regulation of the blood flow rate in the area closer to the catheter entrance, while providing guidance for the blood, slowing down blood flow, and reducing bleeding; the recovery zone can smoothly restore the blood flow rate from a slowed state to a normal state. The smooth change in flow rate can reduce the impact of directly jumping from a low flow rate to a high flow rate on the surrounding tissues, improve the degree of protection of the surrounding tissues, and complete thrombus aspiration more smoothly.

[0033] (7) The main purpose of the upper section structure, middle section structure and lower section structure set at the opening section of the present invention is to allow the thrombus to pass through the opening section smoothly while reducing blood outflow. Here, the upper section structure is equivalent to the acceleration section. In the acceleration section, the blood and thrombus are subjected to acceleration due to the eddy current effect, and both pass smoothly; in the deceleration section, the friction ribs and micro-semicircular protrusions increase the roughness of the inner wall of the pipe, which will cause the fluid to generate more friction resistance when passing through, thereby slowing down the blood flow rate, while the thrombus may maintain a smaller speed reduction due to inertia, and this part of the thrombus is more likely to move to the lower section structure; in the secondary acceleration section, the inclined guide strip in the acceleration section changes the flow direction of the fluid, so that the thrombus is accelerated by additional driving force, while avoiding excessive disturbance of the blood, accelerating the outflow of the thrombus, and increasing the overall thrombus passing rate.

[0034] (8) The present invention can more comprehensively control the flow state of blood in the catheter by combining the flow rate slowing zone and the recovery zone with the acceleration zone, the deceleration zone and the secondary acceleration zone provided at the opening section, thereby alleviating the change in blood flow rate when the blood flow rate enters the trumpet-shaped opening section from the thin catheter and reducing the amount of bleeding; at the same time, the blood flow rate can be changed more slowly and gradually, reducing blood damage and achieving rapid and effective thrombus aspiration. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 is an overall three-dimensional structural diagram of a catheter body in an embodiment of the present invention;

[0037] Figure 2 is a schematic structural diagram of a catheter body in an embodiment of the present invention;

[0038] Figure 3 is a schematic structural diagram of a metal reinforcement layer in a catheter body in an embodiment of the present invention;

[0039] Figure 4 1 is a schematic diagram of the overall structure of a push tube in an embodiment of the present invention;

[0040] Figure 5 is a schematic diagram of the connection structure between the push tube and the catheter tube body in an embodiment of the present invention;

[0041] Figure 6 is a schematic structural diagram of a proximal expansion portion of a catheter in an embodiment of the present invention;

[0042] Figure 7 2 is a schematic structural diagram of a proximal developing ring and a distal developing ring in an embodiment of the present invention;

[0043] Figure 8 Schematic diagram of the connection structure between the recycling wire and the closing ring in an embodiment of the present invention;

[0044] Fig. 9 is a detailed view of the closing ring in an embodiment of the present invention;

[0045] Fig.10 is a schematic structural diagram of a closing ring in an embodiment of the present invention;

[0046] Fig.11 is a layout diagram of the suction source of a conventional suction catheter during the suction process in an embodiment of the present invention;

[0047] Fig.12 is a diagram showing the layout position of the suction source of the suction catheter during the suction process in an embodiment of the present invention;

[0048] Fig.13 is a schematic flow chart of a method for using a suction catheter in an embodiment of the present invention;

[0049] Fig.14 It is a cross-sectional three-dimensional structural diagram of the flow velocity slowing zone and the recovery zone in an embodiment of the present invention;

[0050] Fig.15 Schematic diagram of the cross-sectional structure of the flow velocity slowing zone and the recovery zone in an embodiment of the present invention;

[0051] Fig.16 It is a structural schematic diagram of the upper section structure, the middle section structure and the lower section structure of the opening section in an embodiment of the present invention;

[0052] Fig.17 It is a cross-sectional three-dimensional structural diagram of the upper section structure, the middle section structure and the lower section structure of the opening section in an embodiment of the present invention;

[0053] Fig.18 It is a schematic cross-sectional structure diagram of an upper section structure, a middle section structure and a lower section structure of an opening section in an embodiment of the present invention;

[0054] In the figure: 1, catheter body; 11, catheter body; 111, PTFE film layer; 1111, flow rate slowing area; 1112, recovery area; 1113, slowing ribs; 112, metal reinforcement layer; 1121, braided layer; 1122, spring layer; 1123, single-layer spring non-braided structure; 113, polymer material outer layer; 114, hydrophilic coating; 12, push tube; 13, catheter proximal expansion part; 131, opening section; 1311, upper section structure ; 1312, middle section structure; 1313, lower section structure; 1314, spiral groove; 1315, friction ribs; 1316, semicircular raised structure; 1317, inclined guide strip; 132, transition section; 133, inner layer of woven mesh; 134, outer layer of woven mesh; 14, proximal developing ring; 15, distal developing ring; 16, recovery wire; 17, closing ring; 171, support part; 172, connecting part; 2, handle; 3, sheath; 4, suction power source. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The present invention provides an intracranial suction catheter, wherein the structure of the suction catheter is as follows: Figure 1 As shown, it includes: a catheter body 1, and a handle 2 connected to the catheter body 1; the catheter body 1 includes: a catheter body 11, a push tube 12 connected to the catheter body 11, a catheter proximal expansion part 13 arranged on one end of the catheter body 11 close to the push tube 12, a proximal development ring 14 arranged between the catheter proximal expansion part 13 and the catheter body 11, and a distal development ring 15 arranged at the other end of the catheter body 11; the connection method between the catheter body 11 and the catheter proximal expansion part 13 is one of bonding or welding.

[0057] like Figure 2 As shown, the specifications of the inner diameter and outer diameter of the catheter tube body 11 are one of the inner diameter 1.4mm, outer diameter 1.7mm (5F) or the inner diameter 1.8mm, outer diameter 2.1mm (6F); the tube body structure of the catheter tube body 11 is, from the inside to the outside, a PTFE film layer 111, a metal reinforcement layer 112, a polymer material outer layer 113 and a hydrophilic coating 114.

[0058] like Figure 3As shown, the metal reinforcement layer 112 is a double-layer structure formed by combining a braided layer 1121 and a spring-wound layer 1122, wherein the braided layer 1121 is arranged on the outer layer, and the spring-wound layer 1122 is arranged on the inner layer; the total length of the catheter body 11 is 30 to 50 cm, and the 5 to 10 cm at one end of the catheter body 11 away from the push tube 12 is arranged as a single-layer spring-wound non-braided structure 1123, in order to meet the use characteristics of the suction catheter, that is, the distal end of the catheter needs to be designed to be softer to avoid damage to the blood vessels.

[0059] The catheter body 11 adopts a multi-layer composite structure with different materials arranged in the inner and outer layers, which can well ensure the mechanical strength, radiopacity and biocompatibility of the catheter; at the same time, by arranging proximal and distal developing rings 15, it is convenient to observe the position and condition of the catheter during imaging examinations such as CT.

[0060] like Figure 4 As shown, the total length of the push tube 12 is 90 to 110 cm, and the end close to the catheter body 11 is a hypotube structure, that is, a tubular structure with multiple groups of hollow grooves of different shapes and sizes on the surface. The length of the hypotube structure is 1 / 2 to 1 / 3 of the total length, which is used to reduce the excess rigidity of the push tube 12 during pushing, ensuring that the push tube 12 has a certain support while taking into account sufficient softness; the material of the push tube 12 is one of stainless steel or nickel-titanium alloy, and the outer surface of the push tube 12 is coated with PTFE coating, which is used to reduce the friction between the push tube 12 and the long sheath during pushing.

[0061] like Figure 5 As shown, the push tube 12 is connected to the catheter body 11, and the end of the push tube 12 close to the catheter body 11 is arranged between the braided layer 1121 and the spring layer 1122 of the catheter body 11 close to the push tube 12. The specific arrangement method is: after the spring winding process of the catheter body 11, the 3-5 cm part of the push tube 12 close to the end of the catheter body 11 is pre-placed at the catheter body 11 close to the end of the push tube 12, and the braiding process is performed. At this time, the push tube 12 is between the braided layer 1121 and the spring layer 1122, and the push tube 12 is clamped due to the tension force; when the catheter body 11 is subsequently formed by rheological processes, the catheter body 11 is fixedly connected to the push tube 12; this connection method can not only avoid radial runout of the push tube 12 during the pushing process, but also increase the transmission efficiency of the push tube 12.

[0062] like Figure 6As shown, the proximal expansion portion 13 of the catheter is a double-layer woven mesh structure, including a woven mesh inner layer 133 and a woven mesh outer layer 134. The proximal expansion portion 13 of the catheter is divided into an opening section 131 and a transition section 132. The opening section 131 is a trumpet-shaped structure and is an oblique opening. The average weaving pore size of the opening section 131 is 60-80μm. The transition section 132 is a mesh tube-shaped structure. The average weaving pore size of the transition section 132 is 30-40μm. The trumpet-mouth design is adopted to ensure that the proximal opening of the expansion portion can fit closely to the inner wall of the long sheath after expansion, thereby minimizing the loss of suction force.

[0063] The total length of the proximal expansion portion 13 of the catheter is 3 to 7 cm, the opening section 131 accounts for 1 / 4 of the total length of the proximal expansion portion 13 of the catheter, and the end of the transition section 132 away from the proximal expansion portion 13 of the catheter is connected to the catheter body 11 by one of the methods of bonding or welding, and the inner diameter of the connection of the transition section 132 is equal to the inner diameter of the catheter body 11, and the outer diameter of the connection of the transition section 132 is equal to the outer diameter of the catheter body 11.

[0064] The inner wall of the proximal expansion portion 13 of the catheter is covered with a polymer material layer, and the outer wall is provided with a polymer material layer and a hydrophilic coating from the inside to the outside. The polymer material layer is preferably polyurethane, more preferably thermoplastic polyurethane elastomer (TPU for short), brand Tecothane 1085A, purchased from Shanghai Lubimei New Materials Co., Ltd. The hydrophilic coating material is preferably polyvinyl pyrrolidone (PVP), with a thickness of 0.02-0.06 mm, purchased from Shanghai Luyu Biotechnology Co., Ltd. The PVP coating has good biocompatibility, helps to maintain the natural flow state of blood, reduces coagulation reaction, and therefore has anticoagulation function. At the same time, the PVP coating has good stability in an aqueous environment, and even after long-term immersion, the friction coefficient of the coating will not change significantly, which means that the coating can continue to provide an anticoagulation effect.

[0065] The opening section 131 and the transition section 132 are both woven from nickel-titanium wires that have been heat-treated and shaped, and the number of nickel-titanium wire strands is 48 to 64. The inner and outer TPU polymer layers are integrated with the heat-treated and shaped braided mesh through high-temperature flow, and a layer of PVP hydrophilic coating is coated on the outer layer.

[0066] The proximal expansion portion 13 of the catheter using a double-layer woven mesh structure can well maintain the shape and expandability of the proximal end of the catheter. At the same time, the opening section 131 is designed as a trumpet-shaped structure with an oblique opening, which is conducive to attracting thrombus into the interior of the catheter. At the same time, it can further improve the adhesion between the proximal end of the suction catheter and the inner wall of the long sheath, avoiding the loss of suction force in the suction catheter.

[0067] like Figure 7As shown, the proximal developing ring 14 is set on the braided layer 1121 of the catheter body 11 by welding; the distal developing ring 15 is set on the single-layer spring-wound non-braided structure 1123 at the distal end of the catheter body 11 by welding; wherein the developing ring is made of platinum group metal alloy.

[0068] like Figure 8 As shown, a plurality of recovery wires 16 are arranged in the push tube 12, one end of the recovery wire 16 is connected to the handle 2, and the other end is welded to the end of the connection part 172 of the closing ring 17. This arrangement can realize the contraction and expansion of the opening of the proximal expansion part 13 of the catheter by tightening or withdrawing the recovery wire 16. The material of the recovery wire 16 is one of stainless steel or nickel-titanium alloy.

[0069] like Fig. 9 As shown, the closing ring 17 is a C-shaped annular structure, and the two ends of the closing ring 17 cross and close at the bottom of the proximal expansion part 13 of the catheter, dividing the closing ring 17 into a supporting part 171 and a connecting part 172. The supporting part 171 is arranged between the inner layer 133 of the braided mesh and the outer layer 134 of the braided mesh, and the connecting part 172 extends through the two side holes of the push tube 12 to the recovery wire 16 inside the push tube 12, and the end of the connecting part 172 is welded to the recovery wire 16.

[0070] The closing ring 17 is woven from a plurality of metal braided wires, wherein the number of the metal braided wires is 4 to 10, of which 2 to 4 are braided wires of developing material, and the rest are nickel-titanium wires.

[0071] like Fig.10 As shown, the closing ring 17 adopts a braided structure of multiple braided wires, which can firstly further improve the radial wall adhesion of the catheter tube opening, and due to the flexibility of its braided structure, it can be more closely attached to the inner wall of the long sheath; the tightening and release of the closing ring 17 can be manually controlled by tightening and withdrawing the recovery wire 16 in the push tube 12, thereby controlling the expansion and contraction of the proximal opening of the proximal expansion part. The developing material of the closing ring 17 can facilitate the operator to observe the expansion of the proximal opening.

[0072] The present invention aims to improve the current suction catheter. When the suction catheter is currently used, Fig.11 As shown, it is usually necessary to cooperate with a long sheath to deliver it into the blood circuit. When the suction catheter is in place, its distal port will be close to the thrombus, and suction will be performed by applying negative pressure at the proximal end of the suction catheter. According to the suction efficiency formula Among them, Q is the suction efficiency, P is the suction force, r is the inner diameter of the suction catheter, η is the liquid viscosity, and l is the length of the suction catheter. The suction efficiency is proportional to the inner diameter of the catheter and the suction force. This means that when the suction force is fixed, in order to improve the suction efficiency, the inner diameter of the suction catheter needs to be increased.

[0073] However, since the suction process of the traditional suction catheter is completely carried out inside the catheter and is limited by the size of the long sheath, the room for increasing the inner diameter of the suction catheter is very limited. At the same time, the long sheath is necessary during the use of the suction catheter. Therefore, the suction space can only be increased by improving the structural design of the suction catheter itself, thereby improving its suction efficiency.

[0074] Therefore, the present invention provides a new type of suction method by connecting the suction power source 4 to the long sheath under the condition that the suction source provides the same suction force, specifically as follows Fig.12 As shown, the cross-sectional area of ​​the proximal end of the suction catheter for obtaining the suction force is increased, which solves the problem in the prior art that the inner diameter of the suction catheter is limited due to the size limitation of the long sheath, and improves the suction efficiency.

[0075] By combining the flow rate slowing zone and the recovery zone with the acceleration section, the deceleration section and the secondary acceleration section provided at the opening section 131, the flow state of blood in the catheter can be more comprehensively controlled, the change in blood flow rate when the blood flows from the thin catheter into the trumpet-shaped opening section 131 can be alleviated, and the amount of bleeding can be reduced; at the same time, the blood flow rate can be changed more slowly and gradually, reducing blood damage and achieving rapid and effective thrombus aspiration.

[0076] like Fig.13 As shown, a method for using an intracranial suction catheter provided by the present invention is characterized in that it specifically includes the following steps:

[0077] S1. After the long sheath of the suction catheter reaches the position, insert the suction catheter along the long sheath;

[0078] S2, when the suction catheter enters the sheath 3, the closing ring 17 is tightened by pulling back the handle 2 to ensure that the proximal expansion part 13 of the catheter is in a tightened state;

[0079] S3, after the suction catheter enters the sheath tube 3 and is in place, the handle 2 is released to gradually expand the trumpet-shaped structure of the opening section 131 of the proximal expansion portion 13 of the catheter as the closing ring 17 is released, until it fits with the inner wall of the sheath tube 3; and the opening and closing of the opening section 131 is observed at any time through the display image;

[0080] S4. After the suction catheter is stabilized, a suction power source 4 is added to the proximal end of the sheath 3 to complete the suction of the thrombus.

[0081] In conventional technology, the suction power source 4 needs to be connected to one end of the suction catheter to apply negative pressure for suction. However, since the suction catheter needs to be used with a long sheath, the efficiency that can be improved even if the inner diameter of the suction catheter is changed is very limited. This method connects the suction power source 4 to the long sheath, and completes the suction by contacting the thrombus with the distal port of the suction catheter, thereby improving the suction efficiency.

[0082] Before the suction catheter enters the long sheath, the proximal expansion part is tightened by tightening the closing ring 17, which can effectively reduce the diameter of the catheter and make it easier to pass through the narrow passage of the long sheath. This helps to avoid excessive friction and resistance between the catheter and the inner wall of the long sheath during the pushing process, thereby improving the passability and pushing efficiency of the catheter.

[0083] During the process of the catheter entering the blood vessel, if the proximal expansion part is in an expanded state, it may increase the contact area and friction with the inner wall of the blood vessel, thereby increasing the risk of vascular damage; by tightening the proximal expansion part, this contact and friction can be reduced, reducing the possibility of vascular damage.

[0084] Due to the support of the long sheath, the tightened proximal expansion part can better fit the inner wall of the long sheath, reducing the radial runout and deviation of the catheter. This helps to improve the maneuverability and accuracy of the catheter, allowing the operator to more accurately control the position and direction of the catheter.

[0085] The closing ring 17 contains a developing material, and the opening and closing of the proximal expansion part can be observed at any time through imaging equipment; when the catheter enters the long sheath, keeping the proximal expansion part tightened helps to better observe and locate the position of the catheter, ensuring that the catheter can accurately reach the target area.

[0086] In one or more embodiments, the inner wall of the PTFE film layer 111 inside the catheter body 11 is provided with a plurality of flow rate slowing areas 1111 and recovery areas 1112, which are designed to optimize blood flow, reduce bleeding, and improve the working efficiency of the catheter, such as Fig.14 and Fig.15 shown.

[0087] Specifically, the starting position of the flow slowing zone 1111 is arranged from the center of the catheter tube body 11 to the direction of the push tube 12, and the length of each flow slowing zone 1111 is 1 to 2 cm. Such a length design can ensure the effect while avoiding excessive interference with blood flow. A number of slowing ribs 1113 are arranged on the inner wall of the flow slowing zone 1111 along the circumference of the flow direction. The height of the slowing rib 1113 is 8 to 18 μm, the length of the slowing rib 1113 is 45 to 68 μm, and the width of the slowing rib 1113 is 25 to 30 μm. The flow slowing zone 1111 is used to provide guidance for blood, slow blood flow, and reduce bleeding.

[0088] The flow rate slowing areas 1111 and the recovery areas 1112 are arranged alternately, and the length of each recovery area 1112 is 0.5 to 0.8 cm. The inner wall of the recovery area 1112 is a smooth streamline structure, which is used to restore the flow rate from a slowed state to a normal state and complete the fluid transmission more smoothly.

[0089] The designed flow rate slowing zone 1111 can gradually reduce the blood flow rate in the catheter, and can achieve preliminary regulation of the blood flow rate in the area closer to the catheter entrance, while providing guidance for the blood, slowing down blood flow, and reducing bleeding; the recovery zone 1112 can smoothly restore the blood flow rate from a slowed state to a normal state. The smooth change in flow rate can reduce the impact of directly jumping from a low flow rate to a high flow rate on surrounding tissues, improve the degree of protection of surrounding tissues, and complete thrombus aspiration more smoothly.

[0090] In one or more embodiments, the opening section 131 in the proximal expansion portion 13 of the catheter includes an upper section structure, a middle section structure and a lower section structure. Fig.16 , Fig.17 and Fig.18 shown.

[0091] The upper structure adopts a micro-eddy current structure, which includes a plurality of spiral grooves 1314, the length of the spiral grooves 1314 is 0.25-0.75 cm, the width is 20-25 μm, the turning angle is 30°-65°, and the plurality of spiral grooves 1314 are arranged in a circular array on the inner wall of the opening section 131. The upper structure is an acceleration section, and the micro-eddy current structure accelerates the thrombus, speeding up the flow, which is conducive to the passage of the thrombus.

[0092] The middle section structure includes a plurality of friction ribs 1315, the height of the friction ribs 1315 is 2-6 μm, the length is 0.05-0.25 cm, and the width is 4-12 μm. Each friction rib 1315 is provided with 3-5 micro semicircular protrusion structures 1316, and the diameter of the semicircular protrusion structures 1316 is 1.2-2.5 μm; the middle section structure is a deceleration section, the blood flow rate is slowed down, but the thrombus maintains a higher speed due to inertia, and is easier to flow out of the deceleration section than blood.

[0093] In fluid mechanics, flow resistance is closely related to the radius of the pipe. According to Poiseuille's law, under laminar flow conditions, flow resistance (ΔP) is proportional to pipe length (L), the fourth power of pipe radius (r), fluid viscosity (η), and flow velocity (v). The formula is as follows: ΔP = (8ηLv) / (πr^4). Although Poiseuille's law states that flow resistance is proportional to the fourth power of pipe radius, the change in flow velocity does not only depend on the change in pipe radius. Other factors such as fluid viscosity, pipe length, fluid flow velocity, etc. also affect flow velocity. In the actual blood flow process, due to the viscosity of blood, the complexity of the flow path, and the effect of friction, simply increasing the pipe radius to increase the flow velocity may not be significant.

[0094] However, the increase in the inner diameter of the "deceleration section" (1312) mentioned here relative to its upper section (1313) does not mean that the flow rate will increase significantly, because the friction ribs (1315) and the micro-semicircular protrusions (1316) increase the roughness of the inner wall of the pipe, which will cause the fluid to generate more friction resistance when passing through, thereby slowing down the flow rate. The thrombus has a greater inertia due to its larger mass. In the deceleration section, the blood flow rate slows down, but the thrombus may maintain a smaller speed reduction due to inertia, which helps the thrombus to be more easily removed relative to the blood in the deceleration section.

[0095] The lower section structure includes a plurality of inclined guide strips 1317, which are alternately arranged on the inner wall of the opening section 131. The inclined guide strips 1317 have a length of 0.5 to 0.7 cm, a width of 5 to 10 μm, and an inclination angle of 10° to 15°. The lower section structure is a secondary acceleration section, which is used to accelerate the flow speed of the thrombus again, and together with the upper section structure and the middle section structure, forms an "acceleration-deceleration-secondary acceleration" structure for the flow of the thrombus.

[0096] In order to form a spiral groove, friction ribs and inclined guide strips on the opening section, here, the spiral groove 1314 is prepared with a length of 0.5 cm, a width of 22 μm, a turning angle of 45°, a friction rib 1315 with a height of 4 μm, a length of 0.15 cm, and a width of 8 μm; each friction rib 1315 is provided with 4 micro semicircular protrusion structures 1316 with a diameter of 2 μm; the inclined guide strip 1317 has a length of 0.6 cm, a width of 7 μm, and an inclination angle of 12° as an example to illustrate its formation method, which can adopt micromachining technology, specifically including:

[0097] First, CAD software is used to design a 3D model of the spiral groove (1314), the friction ribs (1315) and the inclined guide strips (1317), and a corresponding mold is prepared; wherein the surface of the template has a preset pattern or structure at the nanometer or micrometer level, and these structures are the friction ribs, micro semicircular protrusion structures and inclined guide strips that are expected to be replicated on the catheter; quartz, silicon and other materials are selected here, and the designed 3D model is transferred to the template by electron beam lithography;

[0098] Then, the opening section of the catheter is placed in a focused ion beam etching device to ensure that the catheter is firmly fixed and accurately positioned; and the previously designed 3D model is imported into the focused ion beam etching device, and the etching parameters are set according to the size and shape of the model, and the ion beam energy is selected: 30keV, etching time is 1h, ion beam current is 1pA, and etching angle is 45°. The software of the device is used to accurately set the etching to realize the etching of several spiral grooves in the upper structure of the catheter;

[0099] Next, a layer of UV curing glue is applied on the surface of the designated part of the catheter opening section, and the nickel alloy wire coated with the embossed glue is aligned with the template, and an appropriate pressure of 20psi is applied. When the nickel alloy wire coated with the embossed glue is aligned with the template and pressure is applied, the pattern on the template is transferred to the surface of the nickel alloy wire through the embossed glue; a UV light source is used to cure the embossed glue, with an exposure time of 30 seconds and an exposure intensity of 100mJ / cm 2 , forming a friction rib structure, a micro-semicircular protrusion structure and an inclined guide strip.

[0100] Finally, the samples were cleaned with a mixed solution of acetone and isopropyl alcohol (1:1 ratio) to remove the residual curing glue and etchant.

[0101] The main purpose of the upper section structure, middle section structure and lower section structure provided at the opening section 131 of the present invention is to allow the thrombus to pass through the opening section smoothly while reducing the outflow of blood. Here, the upper section structure is equivalent to the acceleration section. In the acceleration section, the blood and thrombus pass smoothly due to the acceleration effect of the eddy current. In the deceleration section, the friction ribs and micro-semicircular protrusions increase the roughness of the inner wall of the pipe, which will cause the fluid to generate more friction resistance when passing through, thereby slowing down the blood flow rate, while the thrombus may maintain a smaller speed reduction due to inertia, and this part of the thrombus is more likely to move to the lower section structure; in the secondary acceleration section, the inclined guide strip in the acceleration section changes the flow direction of the fluid, so that the thrombus is accelerated by the additional driving force, while avoiding excessive disturbance of the blood, accelerating the outflow of the thrombus, and increasing the overall thrombus passing rate.

[0102] It should be noted that the “proximal end” in the text refers to the end close to the operator, and the “distal end” refers to the end far away from the operator.

[0103] Embodiment 1

[0104] The present embodiment provides an intracranial suction catheter, comprising: a catheter body 1, and a handle 2 connected to the catheter body 1; the catheter body 1 comprises: a catheter body 11, a push tube 12 connected to the catheter body 11, a catheter proximal expansion portion 13 arranged on one end of the catheter body 11 close to the push tube 12, a proximal developing ring 14 arranged between the catheter proximal expansion portion 13 and the catheter body 11, and a distal developing ring 15 arranged at the other end of the catheter body 11; the catheter body 11 and the catheter proximal expansion portion 13 are connected by welding.

[0105] The specifications of the inner diameter and outer diameter of the catheter tube body 11 are 1.4 mm for the inner diameter and 1.7 mm for the outer diameter (5F); the tube structure of the catheter tube body 11 is, from inside to outside, a PTFE film layer 111 , a metal reinforcement layer 112 , a polymer material outer layer 113 and a hydrophilic coating 114 .

[0106] The metal reinforcement layer 112 is a double-layer structure formed by combining a braided layer 1121 and a spring-wound layer 1122, wherein the braided layer 1121 is arranged on the outer layer and the spring-wound layer 1122 is arranged on the inner layer; the total length of the catheter body 11 is 40 cm, and the 8 cm portion of the catheter body 11 away from one end of the push tube 12 is arranged as a single-layer spring-wound non-braided structure 1123.

[0107] The total length of the push tube 12 is 100 cm, and the end close to the catheter body 11 is a hypotube structure, the length of the hypotube structure is 1 / 2 of the total length; the material of the push tube 12 is nickel-titanium alloy, and the outer surface of the push tube 12 is coated with PTFE coating.

[0108] The push tube 12 is connected to the catheter body 11, and one end of the push tube 12 close to the catheter body 11 is arranged between the braided layer 1121 and the spring layer 1122 of the catheter body 11 close to the push tube 12. The specific arrangement method is: after the spring winding process of the catheter body 11, the 4 cm part of the push tube 12 close to the end of the catheter body 11 is pre-placed at the catheter body 11 close to the end of the push tube 12, and the braiding process is performed. At this time, the push tube 12 is between the braided layer 1121 and the spring layer 1122, and the push tube 12 is clamped due to the tension force; when the catheter body 11 is subsequently formed by rheological processes, the catheter body 11 and the push tube 12 are fixedly connected.

[0109] The proximal expansion portion 13 of the catheter is a double-layer woven mesh structure, including a woven mesh inner layer 133 and a woven mesh outer layer 134. The proximal expansion portion 13 of the catheter is divided into an opening section 131 and a transition section 132. The opening section 131 is a trumpet-shaped structure and is an oblique opening. The average weaving pore size of the opening section 131 is 70 μm. The transition section 132 is a mesh tube structure. The average weaving pore size of the transition section 132 is 35 μm. The trumpet-mouth design is adopted to ensure that the proximal opening of the expansion portion can fit closely to the inner wall of the long sheath after expansion, thereby minimizing the loss of suction force.

[0110] The total length of the proximal expansion portion 13 of the catheter is 5 cm, and the opening section 131 accounts for 1 / 4 of the total length of the proximal expansion portion 13 of the catheter. The end of the transition section 132 away from the proximal expansion portion 13 of the catheter is connected to the catheter body 11 by one of the methods of bonding or welding, and the inner diameter of the connection of the transition section 132 is equal to the inner diameter of the catheter body 11, and the outer diameter of the connection of the transition section 132 is equal to the outer diameter of the catheter body 11.

[0111] The inner wall of the proximal expansion part 13 of the catheter is covered with a polymer material layer, and the outer wall is provided with a polymer material layer and a hydrophilic coating from the inside to the outside. The polymer material layer is a thermoplastic polyurethane elastomer (TPU for short), the brand is Tecothane 1085A, purchased from Shanghai Lubimei New Materials Co., Ltd. The hydrophilic coating material is preferably polyvinyl pyrrolidone (PVP), the thickness of the PVP coating is 0.02 mm, purchased from Shanghai Luyu Biotechnology Co., Ltd.

[0112] The opening section 131 and the transition section 132 are both woven from nickel-titanium wires that have been heat-treated and shaped, and the number of nickel-titanium wire strands is 55. The inner and outer TPU polymer layers are integrated with the heat-treated and shaped braided mesh through high-temperature flow, and a layer of PVP hydrophilic coating is coated on the outer layer.

[0113] The proximal expansion portion 13 of the catheter using a double-layer woven mesh structure can well maintain the shape and expandability of the proximal end of the catheter. At the same time, the opening section 131 is designed as a trumpet-shaped structure with an oblique opening, which is conducive to attracting thrombus into the interior of the catheter. At the same time, it can further improve the adhesion between the proximal end of the suction catheter and the inner wall of the long sheath, avoiding the loss of suction force in the suction catheter.

[0114] The proximal developing ring 14 is set on the braided layer 1121 of the catheter body 11 by welding; the distal developing ring 15 is set on the single-layer spring-wound non-braided structure 1123 at the distal end of the catheter body 11 by welding; wherein the developing ring is made of platinum group metal alloy.

[0115] A plurality of recovery wires 16 are arranged in the push tube 12, one end of the recovery wire 16 is connected to the handle 2, and the other end is welded to the end of the connection part 172 of the closing ring 17. This arrangement can realize the contraction and expansion of the opening of the proximal expansion part 13 of the catheter by tightening or withdrawing the recovery wire 16.

[0116] The closing ring 17 is a C-shaped annular structure. The two ends of the closing ring 17 cross and close at the bottom of the proximal expansion portion 13 of the catheter, dividing the closing ring 17 into a supporting portion 171 and a connecting portion 172. The supporting portion 171 is arranged between the inner layer 133 of the braided mesh and the outer layer 134 of the braided mesh. The connecting portion 172 extends through the two side holes of the push tube 12 to the recovery wire 16 inside the push tube 12, and the end of the connecting portion 172 is welded to the recovery wire 16.

[0117] The closing ring 17 is woven from a plurality of metal braided wires, the number of the metal braided wires being 6, of which 3 are braided wires of developing material and the rest are nickel-titanium wires.

[0118] Embodiment 2

[0119] Embodiment 2 of the present application provides an intracranial suction catheter. The similarities between Embodiment 2 and Embodiment 1 are not repeated here. Embodiment 2 is different from Embodiment 1 in that the inner wall of the PTFE film layer 111 inside the catheter body 11 is provided with a plurality of flow rate slowing areas 1111 and recovery areas 1112.

[0120] The initial setting position of the flow velocity slowing zone 1111 is arranged from the center of the catheter tube body 11 to the direction of the push tube 12. The length of each flow velocity slowing zone 1111 is 1 cm. A plurality of slowing ribs 1113 are arranged circumferentially along the flow direction on the inner wall of the flow velocity slowing zone 1111. The height of the slowing rib 1113 is 10 μm, the length of the slowing rib 1113 is 55 μm, and the width of the slowing rib 1113 is 28 μm. The flow velocity slowing zone 1111 and the recovery zone 1112 are arranged alternately, and the length of each recovery zone 1112 is 0.6 cm.

[0121] Embodiment 3

[0122] Embodiment 3 of the present application provides an intracranial suction catheter. The similarities between Embodiment 3 and Embodiment 1 are not repeated here. The difference between Embodiment 3 and Embodiment 1 is that the opening section 131 in the proximal expansion portion 13 of the catheter includes an upper section structure, a middle section structure and a lower section structure; the upper section structure adopts a micro-vortex structure, and the upper section structure includes a plurality of spiral grooves 1314, the length of the spiral grooves 1314 is 0.5 cm, the width is 22 μm, and the turning angle is 45°. The plurality of spiral grooves 1314 are arranged in a circular array on the inner wall of the opening section 131; the middle section structure includes a plurality of friction ribs 1315, and the height of the friction ribs 1315 is 4 μm, the length is 0.15 cm, and the width is 8 μm. Each friction rib 1315 is provided with four micro semicircular protrusion structures 1316, and the diameter of the semicircular protrusion structure 1316 is 2 μm; the middle section structure is a deceleration section, and the blood flow rate is slowed down, but the thrombus maintains a high speed due to inertia, and is easier to flow out of the deceleration section than blood. The lower section structure includes a plurality of inclined guide strips 1317, which are alternately arranged on the inner wall of the opening section 131, and the inclined guide strips 1317 are 0.6 cm long, 7 μm wide, and have an inclination angle of 12°.

[0123] Embodiment 4

[0124] Embodiment 4 of the present application provides an intracranial suction catheter. The similarities between Embodiment 4 and Embodiment 1 are not repeated here. The difference between Embodiment 4 and Embodiment 1 is that the thickness of the PVP coating material is 0.04 mm.

[0125] Embodiment 5

[0126] Embodiment 5 of the present application provides an intracranial suction catheter. The similarities between Embodiment 5 and Embodiment 1 are not repeated here. The difference between Embodiment 5 and Embodiment 1 is that the thickness of the PVP coating material is 0.06 mm.

[0127] Comparative Example 1

[0128] This comparative example provides an intracranial suction catheter. The difference between this comparative example and the first embodiment is that the opening section is a mesh tube structure that is the same as the transition section.

[0129] Comparative Example 2

[0130] This comparative example provides an intracranial suction catheter. The difference between this comparative example and Example 1 is that a suction power source is connected to one end of the suction catheter to apply negative pressure for suction.

[0131] Comparative Example 3

[0132] This comparative example provides an intracranial suction catheter. The difference between this comparative example and Example 1 is that the tube body structure of the catheter tube body is a PTFE film layer, a metal reinforcement layer and a polymer material outer layer from the inside to the outside.

[0133] Test Example 1

[0134] In order to determine whether the hydrophilic coating in Examples 1-3 falls off after use, a test experiment was designed: a simulated use test was conducted in which a catheter was inserted from the right femoral artery of the vascular model under the guidance of a 0.035-in guide wire, and pushed along the vascular model to the C2 segment of the right internal carotid artery, and the test was repeated 10 times.

[0135] After the catheter was used in simulation, the surface of the hydrophilic coating was coated with Congo red. Under a microscope magnification of 7 times (the microscope objective lens magnification was rotated to 0.7), the coating part of the catheter was observed to see whether it was colored and completely colored. The results are shown in Table 1.

[0136] Table 1 Surface coating integrity test results after simulated use

[0137]

[0138]

[0139] It can be seen from the above table that the hydrophilic coating after Congo red coating in Examples 1 to 3 is completely colored, indicating that the coating does not fall off after simulated use.

[0140] Test Example 2

[0141] This embodiment conducts the following tests on the suction catheters used in Embodiments 1 to 3 and Comparative Examples 1 and 2:

[0142] (1) Patients with anterior circulation occlusion who underwent mechanical thrombectomy were selected as research subjects. There were a total of 148 research subjects, of which 48 used the aspiration catheter thrombectomy in Example 1, 48 used the aspiration catheter thrombectomy in Comparative Example 1, and 52 used the aspiration catheter thrombectomy in Comparative Example 2. All of them used the same suction force for thrombectomy. The results are shown in Table 2.

[0143] Table 2 Summary of mechanical thrombectomy data

[0144] Embodiment 1 Comparative Example 1 Comparative Example 2 Average age 75 75 75 ICA 17(35.4％) 29(60.4％) 32(61.5％) Suction program time (minutes) 42(35-60) 58(42-70) 65(57-75) Successful recanalization 41(85.4％) 27(56.3％) 23(44.2％) Symptomatic intracerebral hemorrhage 3(6.3％) 7(14.6％) 9(17.3％)

[0145] According to the data in the above table, it can be seen that: in the three groups, the average age is 75 years old, and the influence of age factors on the results can be controlled; the ICA incidence rate of Example 1 (35.4%) is the lowest, while the ICA incidence rate of Comparative Example 2 (61.5%) is the highest. This shows that the ICA incidence rate increases with the increase of the suction procedure time.

[0146] The aspiration procedure time of Example 1 was the shortest, with a median of 42 minutes, while the aspiration procedure time of Comparative Example 2 was the longest, with a median of 65 minutes. This once again confirms that the longer the aspiration procedure time, the higher the incidence of ICA.

[0147] The successful recanalization rate dropped from 85.4% in Example 1 to 44.2% in Comparative Example 2. This indicates that the longer the aspiration procedure, the lower the possibility of successful recanalization. The symptomatic intracerebral hemorrhage rate also increased with the increase of aspiration procedure time. Example 1 was 6.3%, while Comparative Example 2 was 17.3%.

[0148] In summary, we can conclude that:

[0149] Under the condition of providing the same suction force, this scheme adopts a new suction method of connecting the suction power source to the long sheath, which increases the cross-sectional area of ​​the proximal end of the suction catheter for obtaining the suction force, shortens the suction time, and thus further improves the suction efficiency; due to the shortened suction time, it can further reduce the incidence of ICA and symptomatic cerebral hemorrhage rate, and improve the successful recanalization rate, thereby ensuring the therapeutic effect while reducing the risk of complications.

[0150] (2) The aspiration catheters in Examples 1 to 3 were used to remove the thrombus, and the blood extracted along with the thrombus was collected and homogenized. The supernatant was taken and the hemoglobin content was detected using a hemoglobin detection kit, and the data were summarized in Table 3.

[0151] Table 3 Summary of hemoglobin content

[0152] Experimental Group Hemoglobin content in blood (μg / mL) Embodiment 1 559±36 Embodiment 2 402±68 Embodiment 3 255±72

[0153] As can be seen from the table above, the hemoglobin content data of Example 1 is the highest, which is 559±36μg / mL, while the data of Example 2 and Example 3 are lower, which are 402±68μg / mL and 255±72μg / mL respectively. This shows that the suction catheter of Example 3 has the best effect in reducing the amount of bleeding; in summary, Example 3 adopts an optimized structure, which can minimize bleeding and has the best effect in clearing thrombus.

[0154] Experimental Example 3

[0155] (1) Static coagulation test:

[0156] Fresh human venous blood was mixed with sodium citrate anticoagulant at a ratio of 9:1 and slowly centrifuged at 1200 rpm for 15 min to obtain platelet-rich plasma; the aspiration catheters in Example 1, Example 4, Example 5 and Comparative Example 3 were randomly selected and placed in 37°C plasma for incubation for 4 hours, and the wall adhesion of each catheter was observed and summarized in Table 4.

[0157] (2) Platelet adhesion test:

[0158] The anticoagulant coating materials used in Example 1, Example 4, Example 5 and Comparative Example 3 were cut into square samples of 5 cm×5 cm, and placed in different test tubes, 10 ml of the above plasma was added to all the test tubes, and all the test tubes were placed in a 37°C water bath shaker for incubation for 60 min at a speed of 60 r / min. After stopping the incubation, the residual blood in each test tube was transferred to another correspondingly marked test tube, and all the test tubes were placed in a blood analyzer to detect the number of platelets in the blood, and the results were summarized in Table 4.

[0159] Table 4 Summary of static coagulation test and platelet adhesion test data for different catheters

[0160] Experimental Group Static coagulation <![CDATA[Platelet count (×10 9 / L)]]> Decreased platelet count in the blood plasma 615 Embodiment 1 No blood cell adhesion 583 5.2％ Embodiment 4 A small amount of blood cells adhere 519 15.6％ Embodiment 5 A small amount of blood cells adhere 482 21.6％ Comparative Example 3 More blood cells adhere 309 49.8％

[0161] As can be seen from the above table, the static coagulation test results show that no blood cells adhere to the surface of the catheter in Example 1, a small amount of blood cells adhere to the surface of the catheter in Examples 4 and 5, and a large amount of blood cells adhere to the surface of the catheter in Comparative Example 3.

[0162] The platelet adhesion test results showed that the number of platelets in the plasma of Example 1 was closest to the number of platelets in the original plasma (615×10 9 / L), 583×10 9 / L, the number of adsorbed platelets decreased the least (5.2%), indicating that the anticoagulant performance is strong and less platelets are adhered; the reduction in the number of adsorbed platelets of the catheter materials of Examples 4 and 5 is greater than that of Example 1 but less than that of Comparative Example 3; the reduction in the number of platelets in the plasma of Comparative Example 3 is the most significant, only 309×10 9 / L, the number of adsorbed platelets decreased the most (49.8%), indicating that its anticoagulant performance was poor, resulting in a large number of platelets being adsorbed.

[0163] In summary, the experimental data show that the anticoagulation and antiplatelet adhesion performance of the suction catheter used in Example 1 is the best, followed by Example 4, and finally Example 5 and Comparative Example 3. This shows that the anticoagulation coating material used in Example 1 performs best in preventing blood coagulation and platelet adhesion.

[0164] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. An intracranial suction catheter, comprising: A catheter body, and a handle connected to the catheter body, characterized in that: The catheter body comprises: a catheter body, a push tube connected to the catheter body, a catheter proximal expansion portion arranged at one end of the catheter body close to the push tube, a proximal development ring arranged between the catheter proximal expansion portion and the catheter body, and a distal development ring arranged at the other end of the catheter body; The proximal expansion portion of the catheter is a double-layer braided mesh structure, including a braided mesh inner layer and a braided mesh outer layer. The proximal expansion portion of the catheter includes an opening section and a transition section. The opening section is a trumpet-shaped structure and is an oblique opening. The opening section in the proximal expansion portion of the catheter includes an upper section structure, a middle section structure and a lower section structure; wherein the upper section structure adopts a micro-vortex structure, and the upper section structure includes a plurality of spiral grooves; the middle section structure includes a plurality of friction ribs, and each of the friction ribs is provided with a micro-semicircular protrusion structure; A cross-closed closing ring is provided at the bottom of the proximal expansion portion of the catheter, and the closing ring is divided into a supporting portion and a connecting portion, and the supporting portion is provided between the inner layer of the braided mesh and the outer layer of the braided mesh. A plurality of recovery wires are provided in the push tube, and the connecting portion extends to the recovery wire inside the push tube through two side holes provided on the push tube; one end of the recovery wire is connected to the handle, and the other end is welded to the end of the connecting portion of the closing ring; The tube body structure of the catheter tube body is composed of a PTFE film layer, a metal reinforcement layer, a polymer material outer layer and a hydrophilic coating from the inside to the outside, wherein the metal reinforcement layer is a double-layer structure formed by combining a braided layer and a spring layer, the braided layer is arranged on the outer layer, and the spring layer is arranged on the inner layer; wherein the inner wall of the PTFE film layer inside the catheter tube body is provided with a plurality of flow rate slowing areas and recovery areas, the starting setting position of the flow rate slowing area is arranged from the center of the catheter tube body toward the direction of the push tube, and a plurality of slowing ribs are arranged on the inner wall of the flow rate slowing area along the circumference of the flow direction, and the flow rate slowing area is used to provide guidance for blood and slow down blood flow.

2. An intracranial suction catheter according to claim 1, characterized in that: The total length of the catheter body is 30 to 50 cm, and the 5 to 10 cm portion of the catheter body away from one end of the push tube is configured as a single-layer spring-wound non-woven structure.

3. An intracranial suction catheter according to claim 2, characterized in that: The specifications of the inner diameter and outer diameter of the catheter tube body are one of the following: inner diameter 1.4 mm, outer diameter 1.7 mm, or inner diameter 1.8 mm, outer diameter 2.1 mm.

4. An intracranial suction catheter according to claim 3, characterized in that: The total length of the push tube is 90 to 110 cm, and one end close to the catheter body is a hypotube structure, and the length of the hypotube structure is 1 / 2 to 1 / 3 of the total length of the push tube.

5. An intracranial suction catheter according to claim 1, characterized in that: The proximal developing ring is arranged on the braided layer of the catheter body by welding; the distal developing ring is arranged on the single-layer spring-wound non-braided structure of the distal end of the catheter body by welding; wherein the developing ring is made of a platinum group metal alloy.

6. An intracranial suction catheter according to claim 1, characterized in that: The closing ring is woven from a plurality of metal braided wires, the number of the metal braided wires being 4 to 10, of which 2 to 4 are braided wires of developing material, and the rest are nickel-titanium wires.

7. An intracranial suction catheter according to claim 1, characterized in that: The average weaving pore size of the opening section is 60-80 μm, the transition section is a mesh tube structure, and the average weaving pore size of the transition section is 30-40 μm.

8. An intracranial suction catheter according to claim 7, characterized in that: The opening section and the transition section are both woven from nickel-titanium wires that have been processed by a heat treatment shaping process, and the number of nickel-titanium wire strands is 48 to 64.

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