Active intracranial thrombus brushing catheter

Abstract

The invention belongs to the technical field of medical instruments, and particularly relates to an active intracranial thrombus brushing catheter. An active intracranial thrombus brushing catheter comprises a handle, a catheter body is sleeved with the handle, a rotating rod is sleeved with the catheter body, thrombus brushing heads are arranged on the rotating rod, tip conical tubes are arranged at the most front ends of the thrombus brushing heads, bearings are arranged between the thrombus brushing heads and the tip conical tubes, and net umbrellas are installed on the bearings. According to the thrombus brush catheter, safety and effectiveness need to be both considered, secondary blockage of blood vessels caused by falling thrombus is prevented, residual thrombus is removed through the thrombus brush, the success rate of thrombus extraction operation treatment is improved, and the risk of secondary thrombus forming is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical devices, and particularly relates to an active intracranial thrombus brush catheter. BACKGROUND

[0002] Interventional therapy is a minimally invasive treatment using modern high-tech means, which mainly introduces special catheters, guide wires and other precision medical instruments into the human body under the guidance of medical imaging equipment to diagnose and locally treat the body's pathological conditions. Its advantages are small trauma, reduced patient pain, high precision, small side effects, small drug dosage, high local drug concentration, no drug resistance, small damage to normal tissues and fast postoperative recovery of patients.

[0003] Cerebral vascular disease refers to a group of diseases occurring in the brain due to intracranial blood circulation disorders causing brain tissue damage. Common ischemic cerebral vascular diseases are transient ischemic attack, cerebral thrombosis, cerebral embolism, etc., which can cause patients to have hemiplegia, monoplegia, sensory loss, aphasia, blindness and other symptoms. Thrombosis is the most common disease in the cardiovascular system, and the causes of thrombosis are various, but can be roughly divided into four causes, which are blood flow slowing down, blood vessel endothelial damage, increased blood coagulation, and vascular wall hardening to form plaques, which are locally not smooth, and blood flow is easy to form vortex in the not smooth place.

[0004] The current common thrombus minimally invasive treatment method is to remove the thrombus by stent, which generally enters through the femoral artery, uses catheter technology to deliver the catheter to the thrombus lesion site, places the thrombus removal stent at the thrombus site through the microcatheter, and then accurately determines the integration of the thrombus and the thrombus removal stent through imaging, and then withdraws the stent to remove the thrombus and save thousands of families.

[0005] However, the thrombus removal stent still has defects, for example: the thrombus remains on the blood vessel wall of the embolism site, although the patient shows good performance after thrombus removal surgery, but the residual thrombus may affect the patient's life safety at any time like a time bomb, so the above problems need to be solved, so an active intracranial thrombus brush catheter is proposed. The mainstream thrombus removal device on the market is a thrombus suction catheter and a thrombus removal stent. These devices do have some effect on removing larger thrombus plaques, but the thrombus suction catheter and the thrombus removal stent have little effect on stubborn thrombus adsorbed on the blood vessel wall for years. SUMMARY

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide an active intracranial thrombus brush catheter.

[0007] To achieve the above-mentioned purposes and other related purposes, the present application provides the following technical solutions: An active intracranial thrombus brush catheter, comprising a handle, a catheter tube sleeved in the handle, a rotating rod sleeved in the catheter tube, a thrombus brush head arranged on the rotating rod, a pointed conical tube at the front end of the thrombus brush head, a bearing between the thrombus brush head and the pointed conical tube, and a net umbrella mounted on the bearing.

[0008] In an embodiment, the catheter tube is a hypotube, and an intermediate layer is arranged between the outer wall of the catheter tube and the rotating rod, the intermediate layer being composed of a ring of rotatingly arranged balls.

[0009] In an embodiment, the rotating rod is a convex hypotube, and the rotating rod is divided into a distal end, a middle end and a proximal end with diameters gradually increasing.

[0010] In an embodiment, the bristles of the thrombus brush head are perpendicular to the rotating rod, and the thrombus brush head is in the shape of a cylinder as a whole; the thrombus brush head is provided with a developing marker wire at each end, and the developing marker wire is made of platinum-iridium alloy.

[0011] In an embodiment, the pointed conical tube is made of silicone, and the pointed conical tube is fixed to the rotating rod; the handle comprises a handle bayonet, and the handle bayonet is connected to the rotating rod.

[0012] In an embodiment, the bearing comprises a bearing one and a bearing two, the bearing one is close to the developing marker wire, the bearing two is close to the pointed conical tube, a net umbrella is connected to the outer ring of the bearing two, the net umbrella is woven by a plurality of umbrella wires, the umbrella wires are expanded to form an umbrella surface, the umbrella surface has gaps or pores, and two umbrella wires are respectively connected to the outer ring of the bearing one and the net umbrella, and a spring is mounted between the bearing one and the bearing two.

[0013] In an embodiment, the rotating rod and the inner ring of the bearing one are in interference fit, and the inner ring of the bearing two and the rotating rod are in clearance fit; the net umbrella is made of a memory alloy, the memory alloy comprises a nickel-titanium alloy wire; the thrombus brush head is made of a degradable polymer, the degradable polymer comprises polylactic acid, and the surface of the bristles of the thrombus brush head is coated with an anticoagulant.

[0014] In an embodiment, the anticoagulant comprises one of heparin sodium and a modified anticoagulant.

[0015] In an embodiment, a method for preparing the modified anticoagulant comprises the following steps: Nicotinic acid and polyethylene glycol diamine are co-dissolved in anhydrous THF, and then a catalyst is added; the reaction is stirred; filtration and purification are performed to obtain P1. Chitosan is dissolved in an acetic acid solution, methyl acryloyl chloride and 1-ethyl imidazole are added dropwise, and the reaction is performed; the pH is adjusted; impurities are removed, and drying is performed to obtain P2. P1 and P2 are dissolved in an ethanol solution; ZnCl2 solution is added, and ultrasonic is performed; a stabilizer is added, stirring is performed, and the pH is adjusted to obtain gel particles. The gel particles are mixed into a PLA solution to obtain the modified anticoagulant.

[0016] In one embodiment, the catalyst comprises DCC, DMAP; the stabilizer comprises a surfactant.

[0017] In one embodiment, the mass ratio of the gel particles to PLA is 2-6:1.

[0018] Compared with the conventional thrombus suction catheter and thrombus removal stent, the present application has the following advantages: 1. The active intracranial thrombus brush catheter prepared by the present application is an interventional instrument for minimally invasive removal of intracranial thrombus. The existing technology enters the intracranial blood vessel through a neurointerventional surgery (such as mechanical thrombectomy), directly brushes or assists in crushing the thrombus, carries a net umbrella at the distal end of the catheter, ensures the thrombus brush to clean the thrombus, and prevents the fallen thrombus plaque from flowing to the distal end with the blood flow, thereby causing intracranial infarction. The design of the present application needs to consider safety (avoiding blood vessel injury) and effectiveness (rapid recovery of blood flow), and also prevents the fallen thrombus from causing secondary occlusion of the blood vessel (the net umbrella catches the fallen thrombus), which is especially suitable for the treatment of acute ischemic stroke (AIS), removes the residual thrombus through the thrombus brush, improves the success rate of thrombectomy surgery treatment, and reduces the risk of thrombus reshaping.

[0019] 2. At present, the mainstream thrombectomy instruments on the market include thrombus suction catheters, thrombus removal stents and the like. The thrombus suction catheter has poor reachability and is prone to folding when facing tortuous and relatively thin blood vessels, thereby failing to complete thrombus suction. The thrombus removal stent cannot remove all the thrombus when facing stubborn thrombus, thereby increasing the risk of thrombus recurrence. In the present application, the catheter body is a soft and slender hypotube, which has strong folding resistance and can easily pass through relatively complex curved blood vessels, thereby ensuring the smooth progress of the surgery.

[0020] 3. In the present application, the active intracranial thrombus brush catheter is delivered to the lesion site through an intermediate catheter or a microcatheter. When the net umbrella enters the blood vessel through the distal end of the intermediate catheter or the microcatheter, the net umbrella is automatically released under the tension of the spring, and the umbrella mouth is attached to the inner wall of the blood vessel. When the thrombus brush rotates to remove the thrombus, the fallen thrombus plaque is collected in the net umbrella, thereby preventing thrombus escape and allowing normal blood flow.

[0021] 4. In the present application, the net umbrella is made of a nickel-titanium alloy wire. The alloy wire is a memory alloy, which can maintain the metal memory performance after high-temperature heat treatment. Even if it is compressed and bound in the distal end of the intermediate catheter or the microcatheter, it can still maintain the umbrella shape after being pushed out.

[0022] 5. In this application, the mesh umbrella wire is welded to the outer ring of the bearing, and the rotating rod is interference-fitted with the inner ring of the first bearing. This ensures that when the thrombus brush is working, the inner ring of the first bearing rotates together with the rotating rod, while the outer ring of the bearing and the mesh umbrella remain stationary. This prevents the mesh umbrella from rotating when the rotating rod rotates, thus avoiding vascular abrasion and injury. The inner ring of the second bearing is clearance-fitted with the rotating rod, ensuring that the second bearing can slide freely on the rotating rod. This ensures that the mesh umbrella can contract freely when the thrombus brush enters the intermediate catheter or microcatheter.

[0023] 6. In this application, the thrombus brush head is made of a biodegradable polymer, which is both soft and tough, ensuring that stubborn thrombi are removed without damaging the blood vessel wall.

[0024] 7. The bristles of the thrombus brush head are coated with an anticoagulant, which can inhibit thrombus regeneration. The modified anticoagulant is more effective than heparin sodium. The multiple anticoagulant mechanisms of the modified anticoagulant lie in: P1 chelating Zn... 2+ Later on Ca 2+ Competitive binding blocks the formation of the prothrombin activation complex in the coagulation cascade; Zn 2+ It can also bind to phospholipids, disrupting the orderly localization of coagulation factors on the vascular wall. P2 is a weakly cationic polysaccharide derived from chitosan, which can reduce platelet aggregation efficiency by electrostatically adsorbing negative charges on the platelet surface; the imidazole side chain has certain antioxidant / anti-stress effects, which is beneficial for inhibiting platelet-stimulated activation pathways. The formed nanogel particles can form a highly hydrophilic repellent layer on the surface of the bristles of the thrombus brush head; this layer can reduce the plasma protein adsorption rate, thereby blocking the formation of coagulation-related biofilms; the stabilizer can enhance the stability and dispersibility of the anticoagulant.

[0025] 8. The pointed conical tube acts as a guide, allowing it to move freely through tortuous blood vessels without damaging the inner wall, thus avoiding the "windowsill effect" that occurs when using a thrombus aspiration catheter.

[0026] 9. The contrast-enhancing marker wire, visible under X-ray, can accurately locate the thrombus lesion, improving the success rate of the procedure. Compared to catheters and balloons that use contrast-enhancing rings, the active intracranial thrombus brush catheter uses a contrast-enhancing marker wire spirally transferred onto a rotating rod, avoiding excessive stiffness at the distal end that would result in poor flexibility and difficulty in pushing the wire.

[0027] 10. The middle layer is composed of a ring of rotating balls to ensure that the friction is minimized during operation and to prevent the tube from overheating. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0029] In the drawings: Figure 1 is the overall structure schematic diagram of the active intracranial thrombus brush catheter of the present application; Figure 2 is the axial anatomical diagram of the active intracranial thrombus brush catheter of the present application; Figure 3 is the local anatomical diagram of the umbrella of the active intracranial thrombus brush catheter of the present application.

[0030] Figure 4 is the axial anatomical diagram of the catheter body of the active intracranial thrombus brush catheter of the present application.

[0031] Figure 5 is the axial anatomical diagram of the handle of the active intracranial thrombus brush catheter of the present application.

[0032] In the drawings, 1. handle, 2. catheter body, 3. thrombus brush head, 4. developing marker wire, 5. rotating rod, 6. pointed conical tube, 7. umbrella, 8. bearing one, 9. ball, 10. handle bayonet, 11. bearing two, 12. spring. DETAILED DESCRIPTION

[0033] The applicant will describe the embodiments of the present application in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application and cannot be understood as a limitation of the present application. In addition, if not specifically stated, all reagents used in the following embodiments are commercially available or can be synthesized according to existing literature or known methods, and the reaction or test conditions not listed are also conventional technical means easily obtained by those skilled in the art. The terms used in the present application are common in the art and can be clearly understood by those skilled in the art, and are not described one by one.

[0034] Example 1 Referring to Figure 1 , an active intracranial thrombus brush catheter, comprising a handle 1.

[0035] Referring to Figure 5 , the handle 1 has a handle bayonet 10.

[0036] The catheter body 2 is sleeved in the handle 1, and the catheter body 2 is a soft and slender hypotube with strong folding resistance, which can easily pass through relatively complex curved blood vessels to ensure the smooth progress of the operation.

[0037] Referring to Figure 2 and Figure 4The wall of the catheter tube 2 is thin, the rotating rod 5 is sleeved in the catheter tube 2, and an intermediate layer is arranged between the outer wall of the catheter tube 2 and the rotating rod 5. The intermediate layer is composed of a row of rotating balls, which can reduce the friction of the rotating rod 5 as much as possible during work, and prevent the catheter tube 2 from being too hot.

[0038] The rotating rod 5 is a convex hypotube, the diameter of the distal end is thin, the outer diameter of the middle end and the proximal end is thick, and the outer diameter of the proximal end is larger than that of the middle end. The distal end and the proximal end of the rotating rod 5 are referred to as the distance between the rotating rod 5 and the handle 1, for example, the proximal end is the part closest to the handle 1.

[0039] The proximal end of the rotating rod 5 is connected to the handle bayonet 10. The thrombus brush head 3 is arranged on the middle end of the rotating rod 5, and the bristles of the thrombus brush head 3 are perpendicular to the rotating rod 5. The thrombus brush head 3 is in the shape of a cylinder as a whole.

[0040] The thrombus brush head 3 is provided with a developing marker wire 4 at both ends. The developing marker wire 4 is made of platinum-iridium alloy. The developing marker wire 4 can be used to accurately locate the thrombus lesion under X-ray, thereby improving the success rate of the operation. The developing marker wire is spirally transferred on the rotating rod, which can avoid the hard distal end and reduce the flexibility, thereby avoiding the difficulty in pushing.

[0041] The thrombus brush head 3 is provided with a sharp tapered tube 6 at the front end. The sharp tapered tube 6 is fixed to the rotating rod 5 and is made of silicone. The sharp tapered tube 6 has a guiding effect and can freely shuttle in the tortuous blood vessel without damaging the inner wall of the blood vessel, thereby avoiding the occurrence of the "window sill effect" during the delivery of the thrombus suction catheter.

[0042] Referring to Figure 3 The distal end of the rotating rod 5 is provided with bearings. The bearings include bearing one 8 and bearing two 11. The bearing one 8 is close to the developing marker wire 4, and the bearing two 11 is close to the sharp tapered tube 6. The umbrella 7 is welded to the outer ring of the bearing two 11. The umbrella 7 is woven by a plurality of umbrella filaments. The woven umbrella filaments can form an umbrella surface after being released. The umbrella surface has gaps or pores, i.e., gaps or pores exist between the plurality of umbrella filaments, which can carry thrombus. The other ends of the additional two umbrella filaments are welded to the outer ring of the bearing one 8, and the other ends are welded to the umbrella 7. In this way, the contraction and release of the umbrella 7 can be matched. The spring 12 is arranged between the bearing one 8 and the bearing two 11. The spring 12 can push the release of the umbrella 7.

[0043] The handle 1 is an integrated driving system interventional instrument control module, which needs to consider torque transmission efficiency, operation safety and human-computer interaction friendliness.

[0044] The operator can control the rotation of the distal end of the active intracranial thrombectomy brush catheter by connecting the handle 1 to the external unit. The speed of the distal end of the active intracranial thrombectomy brush catheter can be controlled by operating the knob on the external unit. The connecting cable on the external unit is inserted into the handle bayonet 10 for locking. The external unit is turned on, and the rotation of the rotating rod 5 is driven by rotating the handle bayonet 10, which ultimately realizes the rotation of the thrombectomy brush head 3.

[0045] Example 2 Unlike Embodiment 1, this embodiment further includes a matching microcatheter or intermediate catheter required for use with the active intracranial thrombus brush catheter. The microcatheter or intermediate catheter is a conventional thrombus microcatheter with imaging and localization capabilities. It is readily available for purchase, and its principle is known to those skilled in the art. It is not an improvement to this application or a key factor affecting this application, and is therefore not shown in the figures and will not be described in detail.

[0046] Specifically, the active intracranial thrombus brush catheter of Example 1 can be used as a disposable active intracranial thrombus brush catheter, which is installed in a microcatheter or intermediate catheter.

[0047] Reference Figure 3 The rotating rod 5 is interference-fitted with the inner ring of the bearing 8. This ensures that when the thrombus brush head 3 is working, the inner ring of the bearing 8 rotates together with the rotating rod 5, while the outer ring of the bearing and the mesh umbrella 7 remain stationary. This prevents the rotating rod 5 from rotating the mesh umbrella 7, which could cause vascular abrasion and injury.

[0048] The inner ring of bearing 211 is fitted with the rotating rod 5 with a clearance, ensuring that bearing 211 can slide freely on the rotating rod 5. This ensures that the net umbrella 7 can retract freely when the thrombus brush head 3 enters the microcatheter or intermediate catheter.

[0049] The active intracranial thrombus brush catheter is delivered to the lesion site through a microcatheter or intermediate catheter. When the net umbrella 7 enters the blood vessel through the distal end of the intermediate catheter or microcatheter, the net umbrella 7 is automatically released under the tension of the spring 12. The opening of the net umbrella 7 will adhere to the inner wall of the blood vessel. When the thrombus brush head 3 rotates to remove the thrombus, the detached thrombus plaque will be collected into the net umbrella 7, which prevents the thrombus from escaping while allowing normal blood flow.

[0050] A more detailed procedure involves the operator assembling the active intracranial thrombus brush catheter with a microcatheter or intermediate catheter. Utilizing the positioning function of the microcatheter or intermediate catheter, the operator pushes it to the site of the intracranial thrombus. First, the conical tip 6 of the active intracranial thrombus brush catheter is pushed out of the microcatheter or intermediate catheter. The conical tip 6 acts as a guide, allowing it to navigate through tortuous blood vessels, or even pass through the thrombus first. Then, the umbrella-shaped guide wire 7 and the contrast-detecting wire 4 are pushed out of the microcatheter or intermediate catheter, with the conical tip 6 guiding the umbrella-shaped guide wire 7 to also pass through the thrombus. The pores of the umbrella-shaped thrombus 7 can trap a portion of the thrombus. The contrast-marking wire 4 is used to locate the thrombus, and then the thrombus brush head 3 is pushed out. The rotating rod 5 is operated by the handle 1 to rotate, which drives the thrombus brush head 3 to rotate and remove the residual thrombus. The thrombus plaque that falls off is collected by the umbrella-shaped thrombus 7. After the removal is completed, the active intracranial thrombus brush catheter is withdrawn back into the microcatheter or intermediate catheter. The thrombus attached to and collected on the umbrella-shaped thrombus 7 and the thrombus brush head 3 is collected together into the microcatheter or intermediate catheter. Finally, the microcatheter or intermediate catheter is withdrawn from the body to complete the thrombus removal.

[0051] Example 3 Unlike Embodiment 1 or Embodiment 2, the net umbrella 7 is further configured to be made of nickel-titanium alloy wire. This alloy wire is a shape memory alloy, which can maintain its metal shape memory properties after high-temperature heat treatment. Even if it is compressed and bound in the microcatheter or intermediate catheter, it can still maintain its umbrella shape after being pushed out.

[0052] Example 4 Unlike Embodiment 1, Embodiment 2, or Embodiment 3, in a further embodiment, the thrombus brush head 3 is made of a biodegradable polymer, such as polylactic acid (PLA). The thrombus brush head 3 is soft yet resilient, ensuring that stubborn thrombi are removed without damaging the blood vessel wall. Furthermore, the bristles of the thrombus brush head 3 are coated with an anticoagulant to inhibit thrombus regeneration.

[0053] Example 5 Based on Example 4, heparin sodium was further selected as the anticoagulant.

[0054] Example 6 Based on Example 5, a modified anticoagulant was used instead of heparin.

[0055] The specific steps for preparing the modified anticoagulant are as follows: 1. Prepare the ingredients: Polyethylene glycol diamine: NH2-PEG-NH2, Mn=2000; THF: Tetrahydrofuran, AR grade; DCC: N,N'-Dicyclohexylcarbodiimide; DMAP: 4-Dimethylaminopyridine; Stabilizer: Pluronic F68.

[0056] 2. Synthesis of nicotinic acid-PEG block copolymer (P1): In 50 mL of anhydrous THF, 1.0 g of nicotinic acid and 1.0 g of polyethylene glycol diamine were dissolved together, followed by the addition of 0.8 g of DCC and 50 mg of DMAP as a catalyst; the reaction was stirred at room temperature for 18 hours; the by-products were removed by filtration, and the product was purified by recrystallization to obtain P1.

[0057] 3. Synthesis of imidazole-based chitosan (P2): 2 g of chitosan was dissolved in 100 mL of 1% acetic acid solution, 1.5 mL of methacryloyl chloride and 1.0 mL of 1-ethylimidazole were added dropwise, and the reaction was carried out at 35°C for 8 h; the pH was adjusted to neutral; impurities were removed and dried to obtain P2 in powder form.

[0058] 4. Preparation of nanogel composite particles: An ethanol solution with a volume ratio of ethanol to water of 1:1 was prepared.

[0059] 200 mg of P1 and 100 mg of P2 were dissolved in 50 mL of the ethanol solution; 1 mL of a 10 mg / mL ZnCl2 solution was slowly added, and ultrasonic treatment was performed for 20 min; 0.1% of a stabilizer was added, and stirring was performed for 30 min; the pH was adjusted to 6.8 to obtain gel particles.

[0060] 5. Preparation of a modified anticoagulant: PLA was dissolved in ethyl acetate to prepare a 10% w / v PLA solution.

[0061] The gel particles were mixed into the PLA solution, and the mass ratio of the gel particles to PLA was 4:1 to obtain a modified anticoagulant.

[0062] It should be noted that, The block copolymer containing a nicotinic acid structure (P1) has a pyridine carboxyl ligand group, which can form a stable multi-ligand structure with Zn 2+ ions; the imidazole side chain of the chitosan derivative (P2) further constructs a dynamic ionic bridge structure with Zn 2+ ions; and a P1-Zn 2+ -P2 three-dimensional network microstructure is formed around the Zn 2+ ions, and gel particles are formed in an aqueous solution; this structure has a certain reversibility and can achieve local anticoagulation.

[0063] The anticoagulation mechanism of the modified anticoagulant is as follows: P1 competes with Ca 2+ ions for the binding of Zn 2+ ions, thereby blocking the formation of the "prothrombin activation complex" in the coagulation cascade; and Zn 2+It can also bind with phospholipids, and disturb the ordered positioning of coagulation factors on the inner wall of blood vessels. P2 is a weak cationic polysaccharide derived from chitosan, which can adsorb the negative charge on the surface of platelets through electrostatic adsorption, and reduce the efficiency of platelet aggregation; the imidazole side chain has certain antioxidant / anti-stress effect, which is conducive to inhibiting the platelet stimulation and activation pathway. The formed nanogel particles can form a high-hydrophilic repulsive layer on the bristle surface of the thrombus brush head 3; this layer can reduce the adsorption rate of plasma proteins, and then block the formation of coagulation-related biological membranes; the stabilizer can enhance the stability and dispersibility of the anticoagulant.

[0064] The concentration of each component is controlled during the preparation of the modified anticoagulant, and medical-grade raw materials are used to avoid increasing toxicity. It is additionally stated that although ZnCl2 is toxic, it provides Zn 2+ after the reaction, and does not bring toxicity to the modified anticoagulant.

[0065] To detect the effect of the anticoagulant, an experiment is set up to evaluate the inhibition effect on the endogenous coagulation pathway: The thrombus brush head 3 is soaked in 100 U / mL of heparin sodium (Example 5) and modified anticoagulant (Example 6) respectively for 10 min, and a coating is formed after soaking to obtain the sample.

[0066] At the same time, a sample of the blank control group is set up, i.e. the thrombus brush head 3 is not soaked in the anticoagulant.

[0067] According to the activated partial thromboplastin time (aPTT) method and using an aPTT kit for detection, fresh plasma is used, sodium citrate is added for anticoagulation, and plasma is prepared by centrifugation; the sample is incubated with the plasma for 3 min, and then the aPTT reagent is added; CaCl2 is added to start the reaction, and the time is counted until coagulation; the extension range (seconds) of the coagulation time of each sample is compared.

[0068] Five thrombus brush heads are prepared in each group, and the experiment is repeated to take the average. The results are as follows: Blank control group: 32.5 seconds; Example 5: 68.3 seconds; Example 6: 72.8 seconds.

[0069] Analysis: The aPTT of the modified anticoagulant is significantly longer than that of heparin sodium, and the modified anticoagulant is superior to heparin sodium in prolonging the coagulation time, and has better anticoagulant performance.

[0070] The above merely describes the preferred embodiments of the present application and is not used to limit the present application, and although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some technical features thereof. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An active intracranial thrombus brush catheter, characterized by, The handle is sleeved with a catheter tube, the catheter tube is sleeved with a rotating rod, the rotating rod is arranged with a thrombus brush head, the thrombus brush head is provided with a pointed conical tube at the front end, a bearing is arranged between the thrombus brush head and the pointed conical tube, and a net umbrella is arranged on the bearing.

2. An active intracranial thrombus brush catheter according to claim 1, wherein, The catheter tube is a hypotube, and an intermediate layer is arranged between the outer wall of the catheter tube and the rotating rod, and the intermediate layer is composed of a circle of rotatingly arranged balls.

3. An active intracranial thrombus brush catheter according to claim 1, wherein, The rotating rod is a convex hypotube, and the rotating rod is divided into a farthest end, a middle end and a nearest end with increasing diameters.

4. An active intracranial thrombus brush catheter according to claim 1, wherein, The bristles of the thrombus brush head are perpendicular to the rotating rod, and the thrombus brush head is in a cylindrical shape as a whole; the thrombus brush head is provided with a developing marker wire at each end, and the developing marker wire is made of platinum-iridium alloy.

5. An active intracranial thrombus brush catheter according to claim 1, wherein, The pointed conical tube is made of silica gel and is fixed to the rotating rod; the handle comprises a handle socket, and the handle socket is connected to the rotating rod.

6. An active intracranial thrombus brush catheter according to claim 4, wherein, The bearing comprises a bearing one and a bearing two, the bearing one is close to the developing marker wire, the bearing two is close to the pointed conical tube, a net umbrella is connected to the outer ring of the bearing two, the net umbrella is woven by a plurality of umbrella wires, the woven umbrella wires are expanded to form an umbrella surface, the umbrella surface has gaps or pores, two umbrella wires are respectively connected to the outer ring of the bearing one and the net umbrella, and a spring is arranged between the bearing one and the bearing two.

7. An active intracranial thrombus brush catheter according to claim 6, wherein, The rotating rod is in interference fit with the inner ring of the bearing one, and the inner ring of the bearing two is in clearance fit with the rotating rod; the net umbrella is made of memory alloy, the memory alloy comprises a nickel-titanium alloy wire; the thrombus brush head is made of degradable polymer, the degradable polymer comprises polylactic acid, and the surface of the bristles of the thrombus brush head is coated with an anticoagulant.

8. An active intracranial thrombus brush catheter according to claim 7, wherein, The anticoagulant comprises one of heparin sodium and a modified anticoagulant; a method for preparing the modified anticoagulant comprises the following steps: Nicotinic acid and polyethylene glycol diamine are co-dissolved in anhydrous THF, and then a catalyst is added; the reaction is stirred; filtration and purification are performed to obtain P1; Chitosan is dissolved in an acetic acid solution, methacryloyl chloride and 1-ethyl imidazole are added dropwise, and the reaction is performed; the pH is adjusted; impurities are removed, and drying is performed to obtain P2; P1 and P2 are dissolved in an ethanol solution; a ZnCl2 solution is added, and ultrasonic is performed; A stabilizer is added, stirring is performed, the pH is adjusted, and gel particles are obtained; The gel particles are mixed into a PLA solution to obtain a modified anticoagulant.

9. An active intracranial thrombus brush catheter according to claim 8, wherein, The catalyst comprises DCC and DMAP; and the stabilizer comprises a surfactant.

10. An active intracranial thrombus brush catheter according to claim 8, wherein, The mass ratio of the gel particles to the PLA is 2-6:1.

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