Bending-adjustable balloon micro-catheter

Abstract

The invention provides a bending-adjustable balloon micro-catheter, and belongs to the technical field of balloon micro-catheters.The bending-adjustable balloon micro-catheter comprises a catheter body, a balloon, a bending mechanism and a feedback mechanism, the catheter body is of a slender tubular structure, and an inner cavity of the catheter body is used for conveying therapeutic drugs or embolism materials or other media; the balloon is located at the far end of the catheter body, is in an ellipsoidal shape and is used for blocking blood flow or expanding blood vessels. The multiple bending mechanisms are sequentially located at the middle section position of the catheter body and are composed of shape memory alloy wires, and the shape memory alloy wires are spirally wound around the outer wall of the catheter body, connected to the catheter body and used for adjusting the bending angle and direction of the catheter body; the feedback mechanisms are pressure sensor arrays, and the number of the feedback mechanisms is eight. The problems that an existing balloon micro-catheter is difficult to accurately reach a target position in a complex blood vessel or cavity, and the blood vessel is prone to being damaged can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of balloon microcatheters, and more particularly, relates to an adjustable-bend balloon microcatheter. Background Art

[0002] Balloon microcatheter technology is an important device widely used in interventional medical treatment, especially in the treatment of vascular lesions and interventional surgeries. The emergence and development of microcatheter technology have greatly improved the accuracy and safety of traditional surgical methods, enabling doctors to perform precise operations in high-risk lesion areas. Balloon microcatheters have significant advantages especially in vascular dilation and thrombus removal, and their application scope covers multiple fields such as coronary artery disease, peripheral artery disease, intracranial artery stenosis, and venous thrombosis.

[0003] A microcatheter is a small-diameter catheter, usually with a diameter between 0.5 mm and 2.5 mm, designed for precise operations through narrow or complex vascular channels. Early interventional surgeries mostly relied on traditional open surgeries, but these methods had disadvantages such as large trauma and long recovery time. With the development of minimally invasive technology, the application of microcatheters has gradually emerged in the medical field. It enters the patient's body through a smaller incision and performs precise operations under image guidance, reducing the patient's pain and recovery time.

[0004] Existing balloon microcatheters are difficult to accurately reach the target position in complex blood vessels or cavities and are prone to causing vascular injury. Summary of the Invention

[0005] In view of this, the present invention provides an adjustable-bend balloon microcatheter, which can solve the problems that existing balloon microcatheters are difficult to accurately reach the target position in complex blood vessels or cavities and are prone to causing vascular injury.

[0006] The present invention is implemented as follows: The present invention provides an adjustable-bending balloon microcatheter, which includes a catheter body, a balloon, a bending mechanism and a feedback mechanism. The catheter body is an elongated tubular structure, and its inner cavity is used to transport therapeutic drugs, embolization materials or other media. The balloon is located at the distal end of the catheter body and is ellipsoidal in shape, and is used to block blood flow or dilate blood vessels. The bending mechanism includes a plurality of shape memory alloy wires, which are sequentially located in the middle section of the catheter body and are composed of shape memory alloy wires. The shape memory alloy wires are helically wound around the outer wall of the catheter body and are connected to the catheter body to adjust the bending angle and direction of the catheter body. The feedback mechanism is a pressure sensor array, and its number is 8, which are evenly distributed on the surface of the balloon to monitor the internal pressure and contact force of the balloon in real time, so as to provide feedback information on the contact force between the balloon and the blood vessel wall, avoid blood vessel damage caused by over-inflation of the balloon, and at the same time, the filling pressure of the balloon can be adjusted according to the contact force to achieve the best therapeutic effect.

[0007] On the basis of the above technical solutions, the adjustable-bending balloon microcatheter of the present invention can also be improved as follows: Among them, the catheter body is composed of three layers: an inner layer, a middle layer and an outer layer. The inner layer is made of polytetrafluoroethylene material and has good lubricity and antithrombotic properties. The middle layer is composed of braided nylon filaments to provide certain support and anti-torsion performance. The outer layer is made of polyimide material to provide biocompatibility and wear resistance. The outer diameter of the catheter body is 0.80 mm, the inner diameter is 0.54 mm, and the length is 100 - 160 cm.

[0008] Furthermore, the shape memory alloy wire of the bending mechanism is made of nickel-titanium alloy, and its phase transition temperature is 40 °C, which is used to precisely control the shape and length of the shape memory alloy wire by controlling the temperature of an external heating device to adjust the bending angle and direction of the catheter. The outer diameter of the shape memory alloy wire of the bending mechanism is 2 mm, and the length is 10 cm.

[0009] Furthermore, each sensor of the feedback mechanism has a diameter of 0.1 mm and a thickness of 0.05 mm, and is connected to an external microprocessor through a wire. The microprocessor is used to collect and process sensor data and transmit the data to an external control system.

[0010] Furthermore, a marking ring is provided at the distal end of the catheter body. The marking ring is made of platinum-iridium alloy and has good X-ray opacity, and is used to display the position of the catheter under X-rays; the marking ring has a thickness of 0.05 mm and a width of 0.5 mm, and is fixed 2 mm proximal to the distal balloon of the catheter body by a medical-grade epoxy resin adhesive; the outer diameter of the marking ring is the same as the outer diameter of the catheter body, and the inner diameter of the marking ring is the same as the inner diameter of the catheter body, so that the marking ring and the catheter body form a smooth transition to avoid additional resistance during intravascular advancement.

[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the setting of the platinum-iridium alloy marker ring can clearly display the position of the catheter under X-ray, improving the accuracy of surgical positioning. The marker ring has the same inner and outer diameters as the catheter body and is fixed with epoxy resin to form a smooth transition structure, avoiding additional resistance during intravascular advancement and reducing the risk of damage to the vascular wall. Precise positioning 2mm proximal to the balloon helps doctors accurately determine the balloon position, ensures accurate positioning of the treatment site, and improves the navigation and positioning capabilities of the microcatheter in complex vascular systems.

[0012] Furthermore, the balloon has a spindle-shaped structure, which is thickest in the middle and gradually becomes thinner at both ends and smoothly transitions to the catheter body; the balloon is made of high-pressure resistant medical silicone rubber material and has good elasticity and strength; the wall thickness of the balloon is 0.08mm, and the maximum expansion diameter is 3mm; the proximal end of the balloon and the distal end of the catheter body are fixed by hot-melt connection, and the thickness of the hot-melt connection is 0.15mm and the length is 1mm; the distal end of the balloon and the catheter body are fixed in the same way to form a sealing structure.

[0013] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the balloon adopts a spindle-shaped structure design, with the thickest part in the middle and gradually tapering at both ends, forming a smooth transition with the catheter body, avoiding scratching and damage to the blood vessel wall when advancing in the blood vessel. The balloon made of high-pressure resistant medical silicone rubber material has good elasticity and strength, and is not easy to rupture when subjected to high-pressure expansion, which improves product safety. The two ends of the balloon are fixed by hot-melt connection to form a stable sealing structure to prevent liquid leakage, ensure the controllability and stability of balloon expansion, and improve the treatment effect and safety of the balloon microcatheter.

[0014] Furthermore, a three-way connector is provided at the proximal end of the catheter body. The three-way connector is made of medical-grade polycarbonate material. The three-way connector includes a main channel, a side channel, and a locking structure. The inner diameter of the main channel matches the inner diameter of the catheter body and is used for introducing a guide wire or delivering a therapeutic drug. The side channel is connected to the inner cavity of the balloon and is used for injecting liquid to inflate the balloon. The locking structure is located at the proximal end of the three-way connector and is used for fixing the guide wire. The three-way connector is connected to the proximal end of the catheter body through a rotary joint, and the rotary joint allows the catheter body to rotate without changing the position of the three-way connector.

[0015] The beneficial effects of adopting the above improvement scheme are as follows: The three-way connector is made of medical-grade polycarbonate material, which has good biocompatibility and mechanical strength. The inner diameter of the main channel matches the inner diameter of the catheter body, facilitating the introduction of a guide wire or the delivery of a therapeutic drug. The side channel is connected to the inner cavity of the balloon, enabling independent control of balloon inflation. The locking structure can fix the position of the guide wire, improving the operation stability. The rotary joint design allows the catheter body to rotate without changing the position of the three-way connector, greatly enhancing the flexibility of catheter manipulation, enabling the doctor to more precisely adjust the catheter position, reducing the surgical operation difficulty, and improving the treatment efficiency.

[0016] Furthermore, a flexible transition section is provided between the balloon and the bending mechanism of the catheter body. The length of the flexible transition section is 15 cm. The flexible transition section is made of polyether block amide material, and its hardness gradually increases from the distal end to the proximal end, forming a hardness gradient structure. The hardness of the distal end of the flexible transition section is 65D, and the hardness of the proximal end is 75D. The flexible transition section is connected to the catheter body through a heat shrinkable tube. The length of the heat shrinkable tube is 5 mm, and the wall thickness is 0.03 mm. The surface of the flexible transition section is coated with a hydrophilic coating, and the thickness of the hydrophilic coating is 0.01 mm, which is used to reduce friction and improve the passing ability of the catheter body.

[0017] The beneficial effects of adopting the above improvement scheme are as follows: The flexible transition section is made of polyether block amide material, and its hardness gradually increases from the distal end to the proximal end, forming a hardness gradient structure, realizing a smooth transition between the rigidity and flexibility of the catheter and avoiding the risk of catheter breakage caused by stress concentration. The heat shrinkable tube connection method ensures the structural strength, and the hydrophilic coating reduces the friction between the catheter and the blood vessel wall, improving the passing ability of the catheter. The design of the flexible transition section enables the catheter to have good pushing performance while maintaining the flexibility of the distal end, greatly improving the passing ability and positioning accuracy of the catheter in complex blood vessels and reducing the risk of blood vessel perforation.

[0018] Further, the pressure sensor array of the feedback mechanism is connected to a ring-shaped hub through a wire. The ring-shaped hub is located 2 mm proximal to the balloon and fixed to the outer wall of the catheter body. The ring-shaped hub has a diameter of 1 mm and a thickness of 0.2 mm and is made of polyimide material. The ring-shaped hub is provided with 8 wire interfaces, and each interface is connected to one of the pressure sensors. A signal processing unit is provided inside the ring-shaped hub for preprocessing the pressure sensor signals. The ring-shaped hub is connected to the signal transmission line inside the catheter body through a micro wire, and the signal transmission line extends along the inner wall of the catheter body to the proximal end of the catheter body.

[0019] The beneficial effects of adopting the above improvement scheme are as follows: The ring-shaped hub is connected to the pressure sensor array, realizing the centralized processing and transmission of signals and simplifying the catheter structure. The ring-shaped hub made of polyimide material has good insulation and biocompatibility. The signal processing unit provided inside the hub preprocesses the sensor signals, improving the signal transmission quality and reducing external interference. The design of connecting through a micro wire to the signal transmission line inside the catheter ensures the stability and accuracy of the signal during long-distance transmission, providing real-time and accurate balloon pressure and contact force feedback information for doctors and effectively preventing blood vessel damage caused by over-expansion of the balloon.

[0020] Further, an insulating layer is coated on the surface of the shape memory alloy wire of the bending mechanism. The insulating layer is made of polyimide material and has a thickness of 0.01 mm. The shape memory alloy wire is wound around the outer wall of the catheter body at a 15-degree helix angle, and the distance between each turn is 1 mm. The two ends of the shape memory alloy wire are respectively connected to electrodes, and the electrodes extend along the outer wall of the catheter body to the proximal end of the catheter body. The winding area of the shape memory alloy wire is 5 cm long and is located 25 cm proximal to the catheter body. The winding area of the shape memory alloy wire is covered with a heat shrinkable tube, and the heat shrinkable tube is used to fix the shape memory alloy wire and provide insulation protection.

[0021] The beneficial effects of adopting the above improvement scheme are as follows: The surface of the shape memory alloy wire is coated with a polyimide insulating layer, preventing current leakage and ensuring patient safety. The 15-degree helix angle winding design enables the catheter to bend in multiple planes, improving the accessibility of the catheter in complex blood vessels. The design with a distance of 1 mm between each turn ensures the uniformity and continuity of the bending. The electrodes extend along the outer wall of the catheter to the proximal end, facilitating the control of the current passing through the shape memory alloy wire. The heat shrinkable tube covering provides additional insulation protection and at the same time fixes the shape memory alloy wire, ensuring that it will not be displaced during operation, greatly improving the reliability and safety of the bending mechanism.

[0022] Compared with the prior art, the beneficial effects of an adjustable-bending balloon microcatheter provided by the present invention are as follows: The catheter body is an elongated tubular structure, whose main function is to transport therapeutic drugs, embolization materials or other media. Through its inner lumen, drugs or media can be accurately delivered to the target location.

[0023] The balloon is located at the distal end of the catheter body and is ellipsoidal in shape. It is mainly used for vascular treatment, such as blocking blood flow or dilating blood vessels. The adjustment of its shape and position is precisely controlled by a feedback mechanism to ensure no damage to the blood vessel wall.

[0024] The bending mechanism consists of multiple shape memory alloy wires, which are helically wound around the outer wall of the catheter body. It allows for precise adjustment of the bending angle and direction of the catheter through temperature control. This design enables flexible operation of the catheter, facilitating treatment by doctors.

[0025] The shape memory alloy wires undergo a phase change when the temperature reaches a certain level, allowing the catheter to be bent and adjusted without manual operation. This self - adaptive control makes the micro - catheter more precise and stable.

[0026] The feedback mechanism monitors the pressure inside the balloon and the contact force with the blood vessel wall through an array of 8 micro - pressure sensors installed on the surface of the balloon. These sensors help obtain real - time force feedback when the balloon contacts the blood vessel wall, avoid blood vessel damage caused by over - inflation, and adjust the filling pressure of the balloon according to the contact force to optimize the treatment effect.

[0027] The catheter body is composed of three layers of materials. Among them: the inner layer is made of polytetrafluoroethylene (PTFE), which has good lubricity and antithrombotic properties, reducing thrombus formation. The middle layer is made of braided nylon filaments, enhancing the support force and anti - torsional property of the catheter. The outer layer uses polyimide (PI), providing biocompatibility and wear resistance to ensure that long - term use will not cause adverse effects on blood vessels.

[0028] The shape memory alloy wires are made of nitinol (Nitinol) and have a phase change temperature of 40°C, enabling them to adjust their shape and length according to the external temperature. Through precise control by an external heating device, the catheter can adjust the bending angle and direction as needed.

[0029] The balloon is made of medical silicone rubber material, with good elasticity and strength, and can work stably under high pressure. The wall thickness of the balloon is 0.08 mm, and the maximum expansion diameter is 3 mm, ensuring that it can provide sufficient expansion force during treatment.

[0030] The connection between the balloon and the catheter body is fixed by a hot - melt method to form a sealed structure, avoiding any leakage.

[0031] The three-way connector is designed to be made of polycarbonate material and includes a main channel, a side channel, and a locking structure, which are used for guide wire guidance, balloon inflation, and guide wire fixation respectively. This design allows for flexible control of the catheter position during the treatment process while ensuring a stable connection between the guide wire and the balloon.

[0032] A flexible transition section is provided between the balloon and the bending mechanism, which serves to transition the hardness, reducing the jamming feeling during catheter operation. The hardness of the transition section gradually increases, helping to smooth the advancement of the catheter. At the same time, its surface is coated with a hydrophilic coating to reduce friction and improve the catheter's passability.

[0033] The pressure sensor in the feedback mechanism is connected to an annular hub through a wire. The annular hub is used to collect signals from the sensor and transmit them to an external microprocessor for analysis. This design allows for real-time monitoring of the balloon status, helping the doctor to make timely adjustments during the treatment process.

[0034] The surface of the shape memory alloy wire is coated with an insulating material (polyimide), which protects it from the external environment and provides electrical insulation function. The alloy wire is wound around the outer wall of the catheter in a spiral manner and fixed and protected by a heat shrink tube to ensure its stability and durability. Description of the Drawings

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0036] Figure 1 It is a schematic structural diagram of an adjustable-bending balloon microcatheter; In the drawings, the list of components represented by each label is as follows: 10. Catheter body; 20. Balloon; 30. Bending mechanism; 40. Feedback mechanism. Detailed Embodiments

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

[0038] Such as Figure 1As shown, it is a schematic structural diagram of an adjustable-bending balloon microcatheter provided by the present invention. In the figure, it includes a catheter body, a balloon, a bending mechanism, and a feedback mechanism. The catheter body is an elongated tubular structure, and its inner cavity is used to transport therapeutic drugs, embolization materials, or other media; the balloon is located at the distal end of the catheter body and is ellipsoidal in shape, used to block blood flow or dilate blood vessels; there are multiple bending mechanisms, which are sequentially located in the middle section of the catheter body and are composed of shape memory alloy wires. The shape memory alloy wires are spirally wound around the outer wall of the catheter body and are connected to the catheter body, used to adjust the bending angle and direction of the catheter body; the feedback mechanism is a pressure sensor array, with a quantity of 8, evenly distributed on the surface of the balloon, used to monitor the internal pressure and contact force of the balloon in real time, so as to provide feedback information on the contact force between the balloon and the blood vessel wall, avoid blood vessel damage caused by over-inflation of the balloon, and at the same time, the filling pressure of the balloon can be adjusted according to the contact force to achieve the best therapeutic effect.

[0039] Among them, in the above technical solution, the catheter body is composed of three layers: an inner layer, a middle layer, and an outer layer. The inner layer is made of polytetrafluoroethylene material, which has good lubricity and antithrombotic properties; the middle layer is composed of braided nylon filaments, providing certain supporting force and anti-torsion performance; the outer layer is made of polyimide material, providing biocompatibility and wear resistance; The outer diameter of the catheter body is 0.80 mm, the inner diameter is 0.54 mm, and the length is 100 - 160 cm.

[0040] Furthermore, in the above technical solution, the shape memory alloy wire of the bending mechanism is made of nickel-titanium alloy, and its phase transition temperature is 40 °C, used to precisely control the shape and length of the shape memory alloy wire by controlling the temperature of an external heating device, so as to adjust the bending angle and direction of the catheter; The outer diameter of the shape memory alloy wire of the bending mechanism is 2 mm, and the length is 10 cm.

[0041] Furthermore, in the above technical solution, the diameter of each sensor of the feedback mechanism is 0.1 mm, the thickness is 0.05 mm, and it is connected to an external microprocessor through a wire. The microprocessor is used to collect and process sensor data and transmit the data to an external control system.

[0042] Furthermore, in the above technical solution, a marker ring is provided at the distal end of the catheter body. The marker ring is made of platinum-iridium alloy and has good X-ray impermeability, used to display the position of the catheter under X-ray; the thickness of the marker ring is 0.05 mm, the width is 0.5 mm, and it is fixed at 2 mm proximal to the distal end balloon of the catheter body through a medical-grade epoxy resin adhesive; the outer diameter of the marker ring is the same as the outer diameter of the catheter body, and the inner diameter of the marker ring is the same as the inner diameter of the catheter body, so that the marker ring and the catheter body form a smooth transition to avoid generating additional resistance during the advancement in the blood vessel.

[0043] Furthermore, in the above technical solution, the balloon has a spindle-shaped structure, being thickest in the middle and gradually tapering at both ends and smoothly transitioning with the catheter body; the balloon is made of high-pressure-resistant medical silicone rubber material, having good elasticity and strength; the wall thickness of the balloon is 0.08 mm, and the maximum inflation diameter is 3 mm; the proximal end of the balloon is fixedly connected to the distal end of the catheter body by hot melting, and the thickness of the hot melting connection part is 0.15 mm and the length is 1 mm; the distal end of the balloon is fixedly connected to the catheter body in the same way to form a sealed structure.

[0044] Furthermore, in the above technical solution, a three-way connector is provided at the proximal end of the catheter body, and the three-way connector is made of medical-grade polycarbonate material; the three-way connector includes a main channel, a side channel, and a locking structure; the inner diameter of the main channel matches the inner diameter of the catheter body and is used for introducing a guide wire or delivering a therapeutic drug; the side channel is connected to the inner cavity of the balloon and is used for injecting liquid to inflate the balloon; the locking structure is located at the proximal end of the three-way connector and is used for fixing the guide wire; the three-way connector is connected to the proximal end of the catheter body through a rotary joint, and the rotary joint allows the catheter body to rotate without changing the position of the three-way connector.

[0045] Furthermore, in the above technical solution, a flexible transition section is provided between the balloon and the bending mechanism of the catheter body, and the length of the flexible transition section is 15 cm; the flexible transition section is made of polyether block amide material, and the hardness gradually increases from the distal end to the proximal end, forming a hardness gradient structure; the hardness of the distal end of the flexible transition section is 65D, and the hardness of the proximal end is 75D; the flexible transition section is connected to the catheter body through a heat-shrinkable tube, the length of the heat-shrinkable tube is 5 mm, and the wall thickness is 0.03 mm; the surface of the flexible transition section is coated with a hydrophilic coating, and the thickness of the hydrophilic coating is 0.01 mm, which is used to reduce friction and improve the passing performance of the catheter body.

[0046] Example 1: Treatment of coronary artery stenosis The patient suffers from atherosclerotic stenosis of the coronary artery, resulting in angina symptoms.

[0047] Adjustable bendability of the microcatheter: The design of this balloon microcatheter can be flexibly bent according to different anatomical structures of the coronary artery, enabling it to adapt to complex vascular curves. During the operation, the doctor can adjust the bending angle of the balloon catheter to avoid sharp turns of the blood vessels, thereby more accurately locating the lesion area.

[0048] Balloon dilation function: After passing through the stenotic area, the balloon can be inflated to dilate the blood vessel and restore blood flow.

[0049] In traditional treatment methods, doctors often face the problems of multi-bent coronary arteries or small blood vessels. With this adjustable-bend balloon microcatheter, doctors can flexibly change the curvature of the catheter through the catheter adjuster to adapt to different bends in the stenotic area. During the balloon dilation process, the dilation force can be monitored through a pressure feedback mechanism to avoid over-dilation and damage to the blood vessel wall. This process can effectively dredge the stenotic blood vessels, restore blood supply to the heart, relieve the angina symptoms of patients, and reduce the occurrence of complications.

[0050] Advantages: Higher operating precision, capable of adapting to complex blood vessels with different anatomical structures.

[0051] Real-time pressure monitoring to ensure safe dilation and avoid damaging the blood vessel wall.

[0052] Minimally invasive treatment, with fast patient recovery and less trauma.

[0053] Example 2: Thrombus removal for peripheral artery disease (PAD) In elderly patients, due to peripheral artery lesions, poor blood circulation in the legs occurs, resulting in venous thrombosis.

[0054] Adjustable-bend catheter and balloon: The adjustable bendability of the balloon microcatheter enables it to pass through multiple stenotic or bent parts in the peripheral artery and flexibly bypass complex vascular structures in the limb.

[0055] Balloon dilation and thrombus removal function: The balloon can not only dilate blood vessels and restore blood flow, but also physically break or push away thrombi through the dilation effect, enabling them to pass through the blood vessels smoothly.

[0056] The peripheral arteries of elderly patients are often affected by atherosclerosis, leading to vascular stenosis and thrombus formation. During the treatment process, doctors introduce the balloon microcatheter into the blood vessel under imaging guidance. Due to the complex vascular bends, conventional microcatheters are difficult to pass through smoothly. By adjusting the bendability of the balloon microcatheter, doctors can easily bypass the vascular bends at the stenosis and accurately reach the thrombus area. After the balloon is inflated, it not only dilates the blood vessels, promotes blood flow, but also squeezes or removes the thrombus from the blood vessels, preventing the thrombus from continuing to block the blood vessels.

[0057] Advantages: Highly flexible, capable of adapting to complex vascular paths and ensuring the smooth progress of thrombus removal operations.

[0058] Through balloon dilation treatment, blood flow is restored and patient symptoms are relieved.

[0059] Reduces the trauma and recovery time of traditional surgeries, and the effect is remarkable.

[0060] Example 3: Interventional treatment for intracranial artery stenosis The blood vessels in the brain are stenosed, increasing the risk of stroke, and urgent interventional treatment is needed.

[0061] Precision positioning and adjustable bending catheter: Intracranial artery stenosis usually occurs at the base of the skull or at the curved parts of cerebral arteries, where the operation is often difficult. The adjustable bending property of the balloon microcatheter is especially suitable for the treatment of such complex blood vessels. By adjusting the bending angle of the catheter, doctors can perform treatment at the precise location.

[0062] Pressure feedback mechanism: This microcatheter is equipped with a pressure feedback system, which monitors the pressure of the blood vessel wall in real time during the dilation process to avoid complications such as rupture of cerebral blood vessels caused by over-dilation.

[0063] This embodiment involves treating the stenosed part of the intracranial artery. Since cerebral blood vessels are usually small and complexly curved, it is difficult for traditional treatment methods to achieve the best treatment effect. Doctors enter the artery through image guidance and precisely introduce the balloon microcatheter into the intracranial blood vessels. By adjusting the bending angle of the catheter, the catheter can smoothly pass through the complex blood vessel path and finally reach the stenosed part. After the balloon is inflated and dilated, it not only widens the blood vessel and restores blood supply to the brain but also avoids the risks of large-scale surgery. During the whole operation process, the pressure feedback mechanism can monitor the blood vessel wall pressure in real time to ensure safety.

[0064] Advantages: High-precision operation, especially suitable for cerebral blood vessels in the stenosed part.

[0065] The adjustable bending property helps the catheter bypass the complex blood vessel path.

[0066] Real-time monitoring of the dilation pressure to avoid complications such as rupture of cerebral blood vessels caused by operation errors.

[0067] Furthermore, in the above technical solution, the pressure sensor array of the feedback mechanism is connected to the annular hub through a wire. The annular hub is located 2 mm proximal to the balloon and fixed to the outer wall of the catheter body; the diameter of the annular hub is 1 mm and the thickness is 0.2 mm, which is made of polyimide material; there are 8 wire interfaces on the annular hub, and each interface is connected to a pressure sensor; a signal processing unit is arranged inside the annular hub for preprocessing the pressure sensor signals; the annular hub is connected to the signal transmission line inside the catheter body through a micro wire, and the signal transmission line extends along the inner wall of the catheter body to the proximal end of the catheter body.

[0068] Furthermore, in the above technical solution, an insulating layer is coated on the surface of the shape memory alloy wire of the bending mechanism. The insulating layer is made of polyimide material and has a thickness of 0.01 mm. The shape memory alloy wire is wound around the outer wall of the catheter body at a 15-degree helix angle, and the spacing between each turn is 1 mm. The two ends of the shape memory alloy wire are respectively connected to electrodes, and the electrodes extend along the outer wall of the catheter body to the proximal end of the catheter body. The winding area length of the shape memory alloy wire is 5 cm and is located 25 cm from the proximal end of the catheter body. The winding area of the shape memory alloy wire is covered with a heat shrinkable tube, which is used to fix the shape memory alloy wire and provide insulation protection.

[0069] Specifically, the principle of the present invention is as follows: During use, check the catheter, balloon and connection device to ensure there is no damage or leakage. Check whether the shape memory alloy wire functions properly and confirm that the temperature control device can be used normally. Clean all relevant instruments, including the catheter and balloon, with an appropriate disinfectant to ensure aseptic operation. Connect the three-way connector of the catheter to the corresponding infusion system and pressure monitoring device. Through the conventional blood vessel puncture method, insert the catheter through the blood vessel to the target position. The doctor will use X-ray guidance to ensure that the catheter reaches the treatment area. At this time, the catheter maintains a straight shape. Through the pressure sensor and feedback system, monitor the position and pressure of the catheter and balloon in real time to ensure there is no abnormality. According to the treatment needs, use an external temperature control device to adjust the bending angle of the catheter. By changing the temperature of the shape memory alloy wire, the catheter is bent at the desired position. At this time, the temperature should be precisely controlled to avoid excessive bending or damage to the catheter. Use the feedback mechanism (pressure sensor) to monitor the contact pressure between the catheter and the blood vessel wall to ensure that the catheter does not cause excessive pressure or damage to the blood vessel wall. Through the infusion system, inject an appropriate gas or liquid into the balloon to control the inflation of the balloon. When the balloon inflates, adjust the infusion volume according to the real-time pressure feedback to ensure that the balloon expands evenly and does not over-inflate, avoiding damage to the blood vessel wall. The balloon can be used for treatments such as blood vessel dilation, drug delivery, and thrombus removal, depending on the specific treatment plan. During the dilation process, monitor the internal pressure of the balloon and the contact force with the blood vessel wall in real time. If excessive or too little pressure is sensed, adjust the balloon inflation volume to ensure the safety and effectiveness of the treatment. If it is necessary to keep the balloon inflated for a long time, the balloon can be maintained in the desired inflated state by precisely controlling the gas injection and the settings of the temperature control device. After the treatment is completed, confirm through the feedback system that the treatment area has been effectively treated, and then slowly remove the catheter and balloon. After removing the catheter, the doctor will confirm the treatment effect through imaging examinations (such as angiography) and ensure that the blood vessel is not further blocked.

Claims

1. An adjustable bend balloon microcatheter, characterized in that: The invention comprises a catheter body, a balloon, a bending mechanism and a feedback mechanism. The catheter body is a slender tubular structure, and its inner cavity is used to deliver therapeutic drugs or embolic materials or other media. The balloon is located at the distal end of the catheter body, is ellipsoidal in shape, and is used to block blood flow or dilate blood vessels. The bending mechanism comprises a plurality of shape memory alloy wires, which are sequentially located at the middle section of the catheter body. The shape memory alloy wires are spirally wound around the outer wall of the catheter body and are connected to the catheter body to adjust the bending angle and direction of the catheter body. The feedback mechanism is an array of 8 pressure sensors, which are evenly distributed on the surface of the balloon and are used to monitor the internal pressure and contact force of the balloon in real time to provide feedback information on the contact force between the balloon and the blood vessel wall to avoid excessive expansion of the balloon causing blood vessel damage. At the same time, the filling pressure of the balloon can be adjusted according to the contact force to achieve the best therapeutic effect.

2. The adjustable bend balloon microcatheter according to claim 1, characterized in that: The catheter body is composed of a three-layer structure of an inner layer, a middle layer and an outer layer. The inner layer is made of polytetrafluoroethylene material, which has good lubricity and anti-thrombotic properties; the middle layer is made of braided nylon wire, which provides a certain support force and anti-torsion performance; the outer layer is made of polyimide material, which provides biocompatibility and wear resistance; The catheter body has an outer diameter of 0.80 mm, an inner diameter of 0.54 mm, and a length of 100-160 cm.

3. The adjustable bend balloon microcatheter according to claim 2, characterized in that: The shape memory alloy wire of the bending mechanism is made of nickel-titanium alloy, and its phase transition temperature is 40°C. It is used to accurately control the shape and length of the shape memory alloy wire by controlling the temperature of the external heating device, so as to adjust the bending angle and direction of the catheter; The shape memory alloy wire of the bending mechanism has an outer diameter of 2 mm and a length of 10 cm.

4. The adjustable bend balloon microcatheter according to claim 3, characterized in that: Each sensor of the feedback mechanism has a diameter of 0.1 mm and a thickness of 0.05 mm, and is connected to an external microprocessor via a wire. The microprocessor is used to collect and process sensor data and transmit the data to an external control system.

5. The adjustable bend balloon microcatheter according to claim 4, characterized in that: A marking ring is provided at the distal end of the catheter body. The marking ring is made of platinum-iridium alloy and has good X-ray opacity, and is used to display the position of the catheter under X-rays; the marking ring has a thickness of 0.05 mm and a width of 0.5 mm, and is fixed 2 mm proximal to the distal balloon of the catheter body by a medical-grade epoxy resin adhesive; the outer diameter of the marking ring is the same as the outer diameter of the catheter body, and the inner diameter of the marking ring is the same as the inner diameter of the catheter body, so that the marking ring and the catheter body form a smooth transition to avoid additional resistance during intravascular advancement.

6. The adjustable bend balloon microcatheter according to claim 5, characterized in that: The balloon has a spindle-shaped structure, which is thickest in the middle and gradually becomes thinner at both ends and smoothly transitions to the catheter body; the balloon is made of high-pressure resistant medical silicone rubber material and has good elasticity and strength; the wall thickness of the balloon is 0.08mm, and the maximum expansion diameter is 3mm; the proximal end of the balloon and the distal end of the catheter body are fixed by hot-melt connection, and the thickness of the hot-melt connection is 0.15mm and the length is 1mm; the distal end of the balloon and the catheter body are fixed in the same way to form a sealing structure.

7. The adjustable bend balloon microcatheter according to claim 6, characterized in that: A three-way connector is provided at the proximal end of the catheter body, and the three-way connector is made of medical-grade polycarbonate material; the three-way connector includes a main channel, a side channel and a locking structure; the inner diameter of the main channel matches the inner diameter of the catheter body, and is used to introduce a guide wire or deliver therapeutic drugs; the side channel is connected to the inner cavity of the balloon, and is used to inject liquid to inflate the balloon; the locking structure is located at the proximal end of the three-way connector, and is used to fix the guide wire; the three-way connector is connected to the proximal end of the catheter body through a rotating joint, and the rotating joint allows the catheter body to rotate without changing the position of the three-way connector.

8. The adjustable bend balloon microcatheter according to claim 7, characterized in that: The catheter body is provided with a flexible transition section between the balloon and the bending mechanism, and the length of the flexible transition section is 15 cm; the flexible transition section is made of polyether block amide material, and the hardness gradually increases from the distal end to the proximal end, forming a hardness gradient structure; the hardness of the distal end of the flexible transition section is 65D, and the hardness of the proximal end is 75D; the flexible transition section is connected to the catheter body through a heat shrink tube, and the heat shrink tube is 5 mm long and has a wall thickness of 0.03 mm; the surface of the flexible transition section is coated with a hydrophilic coating, and the thickness of the hydrophilic coating is 0.01 mm, which is used to reduce friction and improve the passability of the catheter body.

9. The adjustable bend balloon microcatheter according to claim 8, characterized in that: The pressure sensor array of the feedback mechanism is connected to the annular hub through a wire, and the annular hub is located 2 mm proximal to the balloon and fixed to the outer wall of the catheter body; the annular hub has a diameter of 1 mm and a thickness of 0.2 mm and is made of polyimide material; the annular hub is provided with 8 wire interfaces, each of which is connected to one of the pressure sensors; a signal processing unit is provided inside the annular hub for preprocessing the pressure sensor signal; the annular hub is connected to the signal transmission line in the catheter body through a micro-wire, and the signal transmission line extends along the inner wall of the catheter body to the proximal end of the catheter body.

10. The adjustable bend balloon microcatheter according to claim 9, characterized in that: The surface of the shape memory alloy wire of the bending mechanism is coated with an insulating layer, which is made of polyimide material and has a thickness of 0.01 mm; the shape memory alloy wire is wound around the outer wall of the catheter body at a helical angle of 15 degrees, and the spacing between each turn is 1 mm; the two ends of the shape memory alloy wire are respectively connected to electrodes, and the electrodes extend along the outer wall of the catheter body to the proximal end of the catheter body; the winding area of ​​the shape memory alloy wire is 5 cm long and is located 25 cm from the proximal end of the catheter body; the winding area of ​​the shape memory alloy wire is coated with a heat shrink tube, and the heat shrink tube is used to fix the shape memory alloy wire and provide insulation protection.

Images