Percutaneous artery and vein split type artificial blood vessel system for hemodialysis and use method of percutaneous artery and vein split type artificial blood vessel system

Abstract

The invention relates to a percutaneous artery and vein split type artificial blood vessel system for hemodialysis and a using method of the percutaneous artery and vein split type artificial blood vessel system. The percutaneous artery and vein split type artificial blood vessel system comprises two infusion devices completely implanted subcutaneously and two sections of independent blood vessel substitutes. The diaphragm of the infusion device is made of a high-elasticity biocompatible material, and a microstructure and an antibacterial coating are designed on the surface of the diaphragm, so that the sealing performance and the anti-infection performance are ensured; the blood vessel substitute reduces turbulence and thrombus risks through inner diameter matching, conical transition section optimization and antibacterial treatment. The system reliability is further improved through key connection point stability testing and implantation position optimization. According to the application, the stability and safety of a hemodialysis channel are remarkably improved, and the infection and complication risk is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical devices, in particular to a split type artificial blood vessel system for percutaneous arteriovenous and its use method. BACKGROUND

[0002] In current clinical practice, autologous arteriovenous fistula (AVF) is generally considered as the gold standard for vascular access in hemodialysis patients due to its lower complication rate and longer service life. However, not all patients have the anatomical conditions to establish AVF, such as poor vascular conditions, previous surgical history or multiple puncture injuries, etc. For this part of patients who cannot establish AVF, the existing technology mainly provides two alternative vascular access schemes: artificial blood vessel arteriovenous fistula (Arteriovenous Graft, AVG) and central venous catheter (Central Venous Catheter, CVC). Artificial blood vessel arteriovenous fistula usually connects a piece of biocompatible material (such as polytetrafluoroethylene, ePTFE) made of artificial blood vessel between the artery and vein of the patient through surgery, thereby forming a high flow rate blood access under the skin for repeated puncture and blood drainage during dialysis. This scheme to some extent makes up for the limitations of AVF and provides a feasible dialysis access for many patients, especially for patients with poor vascular conditions or unsuitable vascular anatomy for AVF formation. Central venous catheter is usually a flexible catheter placed in the central vein (such as internal jugular vein, subclavian vein or femoral vein) of the patient to provide immediate or temporary hemodialysis access. Its advantage is that the operation is relatively simple, and the dialysis access can be quickly established, especially suitable for emergency dialysis or as a transition scheme before establishing a permanent access.

[0003] CN113694285A proposes a similar dialysis access system, including an arterial end and a venous end artificial blood vessel, both ends are provided with a closer and controlled by a water bag. However, this technology does not involve the details of the septum design and the non-core needle puncture, and the system structure is relatively simple.

[0004] CN106821544B describes a non-blocking type release artificial blood vessel system, which solves the problem of artificial suture anastomosis, but its technical focus is on the stent design, which is significantly different from the split type artificial blood vessel system of the present application.

[0005] US8652195B2 provides an artificial blood vessel design with a lock, mainly used for intravascular folding back connection, which is different from the technical direction of the present application.

[0006] In summary, whether it is an artificial blood vessel fistula that requires repeated puncture and bears the risk of local complications, or a central venous catheter that faces the threat of systemic infection and central vein injury, the existing technology has certain limitations in balancing long-term patency rate, low complications, low infection risk and convenient operation. Therefore, how to design a new type of vascular access scheme can effectively reduce many complications caused by repeated puncture or long-term indwelling catheter in the prior art, while reducing the risk of infection, and at the same time ensuring long-term patency rate and operational convenience, has become the key challenge and technical problem to be solved currently faced by the technical personnel in the field. SUMMARY

[0007] The present application relates to a percutaneous arteriovenous split type artificial blood vessel system for hemodialysis and its use method, aiming to solve the complication problem caused by repeated puncture or long-term indwelling catheter in the prior art, while reducing the risk of infection and ensuring the long-term patency of the access.

[0008] The present application sets up two completely implanted subcutaneous infusion devices, which are connected to the artery and vein respectively, and each infusion device contains a diaphragm inside. The diaphragm is made of a highly elastic and biocompatible material, and a specific microstructure is designed on its surface to reduce the risk of tearing the material during puncture. The thickness of the diaphragm is set to 0.8-1.2mm, and it can still maintain its sealing performance after being vertically punctured 100 times by a 14G coreless needle through mechanical testing. The microstructure on the surface of the diaphragm is composed of groove arrays with a diameter of 50-100 microns. The design of these grooves can disperse the stress concentration during puncture, thereby prolonging the service life of the diaphragm. In addition, the surface of the diaphragm has also been treated with antibacterial properties. The coating material is a silver ion-containing compound, and the coating thickness is controlled between 0.05-0.1 microns, which can inhibit the adhesion and reproduction of bacteria.

[0009] The present application further realizes the blood flow connection between the artery and the vein through two independent blood vessel substitutes. One end of the first blood vessel substitute is connected to the artery through surgery, and the other end is connected to the arterial end infusion device through subcutaneous tunneling technology; one end of the second blood vessel substitute is connected to the vein through surgery, and the other end is connected to the venous end infusion device through subcutaneous tunneling technology. The two blood vessel substitutes are not connected to each other in the body, ensuring one-way blood flow from the artery to the vein. The material of the blood vessel substitute is selected from polymers with biocompatibility and anticoagulant properties, and the inner and outer surfaces are specially treated to reduce the risk of postoperative infection. The outer surface is coated with an antibacterial coating, and the coating material is a silver ion compound, with a coating thickness of 0.1 to 0.2 microns. The preparation process of the antibacterial coating includes immersing the blood vessel substitute in an antibacterial solution for 30 minutes, followed by drying in a sterile environment for 2 hours, with the environmental humidity controlled at 50%. Antibacterial performance tests show that the coating can effectively inhibit the growth of common pathogenic bacteria within 24 hours. The inner surface is treated to optimize the smoothness, and a microscope is used to ensure that there are no defects that can cause thrombosis.

[0010] To ensure the stability of blood flow, the inner diameter of each blood vessel substitute needs to match the inner diameter of the corresponding blood vessel. Specifically, after measuring the inner diameter of the artery and the vein, the inner diameter of the first blood vessel substitute is selected to be 90% to 100% of the inner diameter of the artery, and the inner diameter of the second blood vessel substitute is selected to be 90% to 100% of the inner diameter of the vein. The two ends of each blood vessel substitute are provided with a tapered transition section, and the length of the tapered transition section is twice the inner diameter of the blood vessel substitute, which is used to reduce the turbulence phenomenon during blood flow. Through finite element analysis to simulate the stress distribution of the tapered transition section at different blood flow velocities, its length and angle are adjusted so that its turbulence intensity is less than 5% when the blood flow velocity is 0.2 meters per second. The surface smoothness of the tapered transition section is checked by scanning electron microscopy to ensure that there are no microscopic defects that can cause thrombosis.

[0011] The implantation position of the infusion device is optimized after obtaining the anatomical structure data of the patient through three-dimensional imaging technology. A digital model containing bone, muscle and blood vessel distribution is constructed, and candidate implantation areas are set in the model. The candidate areas need to meet the requirements of being no more than 5 centimeters away from the artery or vein entrance and being located in the range of 1 to 2 centimeters in subcutaneous tissue depth. Based on the candidate areas, a surgical difficulty score is calculated for each area, and the score factors include surgical incision length, operation space size and postoperative recovery time. Finally, the area with the lowest surgical difficulty score is selected as the implantation position, and an accurate implantation path is generated through computer-aided design software. Before actual surgery, virtual reality technology is used to simulate and verify the surgical path to ensure the safety and accuracy of the implantation process.

[0012] This invention also tested the stability of critical connection points. The connection points between the first segment of the vascular substitute and the artery, and between the second segment of the vascular substitute and the vein, were marked as critical connection points. Dynamic pressure was applied to these connection points, ranging from 80 mmHg to 120 mmHg, for 24 hours. Pressure changes and displacement data at the critical connection points were recorded, and their sealing and tensile properties were analyzed. After the dynamic pressure test, the critical connection points were examined under a microscope to ensure there were no cracks or material deformation. Based on the test results, the design parameters of the connection ends were adjusted, including increasing the length of the connection ends or optimizing the surface roughness of the connection ends, until the stability requirements were met.

[0013] This invention significantly improves the stability and safety of vascular access during hemodialysis through the aforementioned technical means. The diaphragm design of the infusion device reduces the risk of injury during puncture, while the antibacterial coating treatment reduces the possibility of infection. Two independent vascular replacements, through strict inner diameter matching and tapered transition optimization, ensure stable blood flow and reduce the risk of turbulence and thrombosis. Stability testing at key connection points and optimized implantation site design further improve system reliability and surgical safety. Long-term performance testing of the antibacterial coating verifies its effectiveness in long-term use, resolving many problems caused by repeated punctures or long-term indwelling catheters in existing technologies. Attached Figure Description

[0014] Appendix Figure 1 Flowchart Detailed Implementation

[0015] This invention relates to a percutaneous arteriovenous split-type artificial blood vessel system for hemodialysis and its usage method. Its purpose is to solve the complications caused by repeated punctures or long-term indwelling catheters in existing technologies through specific structural design and material selection, while reducing the risk of infection and ensuring long-term patency of the access. This embodiment will describe in detail the specific composition, installation method, and operating principle of the system, and comprehensively demonstrate its technical solution through actual operation steps.

[0016] The system includes two fully subcutaneous infusion devices connected to an artery and a vein respectively. Each infusion device contains a septum made of a highly elastic and biocompatible material with a thickness of 0.8-1.2 mm. The surface of the septum is designed with specific microstructures composed of groove arrays with a diameter of 50-100 microns, which can disperse stress concentration during puncture, thereby prolonging the service life of the septum. The surface of the septum is also treated with an antibacterial coating, with a silver ion-containing compound as the coating material and a thickness of 0.05-0.1 microns. In actual production, the septum is first formed into a basic shape by injection molding, then the required groove array is processed on its surface by laser etching, and finally the antibacterial coating is applied by spraying. To ensure the sealing performance of the septum, mechanical testing is required, including checking whether the septum can maintain its sealing performance after being punctured 100 times by a 14G coreless needle. The test results show that the septum can effectively prevent liquid leakage after 100 punctures, meeting the use requirements.

[0017] Two infusion devices are implanted in the patient's body through surgical operation and connected to an artery and a vein respectively. The arterial end infusion device is connected to one end of the first vascular substitute through subcutaneous tunneling technology, and the other end of the first vascular substitute is connected to the artery through surgical operation. The venous end infusion device is connected to one end of the second vascular substitute through subcutaneous tunneling technology, and the other end of the second vascular substitute is connected to the vein through surgical operation. The two sections of vascular substitutes are not connected to each other in the body, ensuring one-way flow of blood from the artery to the vein. The material of the vascular substitute is a polymer with biocompatibility and anticoagulant properties, and the inner and outer surfaces are specially treated to reduce the risk of postoperative infection. The outer surface is coated with an antibacterial coating, with a silver ion compound as the coating material and a thickness of 0.1-0.2 microns. The inner surface is treated for smoothness optimization, and a microscope is used to ensure that there are no defects that may cause thrombosis. In actual production, the vascular substitute is first formed into a basic tubular structure by extrusion molding, then the antibacterial coating is applied on the outer surface by dipping, and the coating thickness is precisely controlled by adjusting the dipping time. The smoothness optimization of the inner surface is completed by polishing, and finally the inner surface is checked using a scanning electron microscope to ensure that there are no microscopic defects.

[0018] To ensure the stability of blood flow, the inner diameter of each vascular substitute needs to match the inner diameter of the corresponding blood vessel. Specifically, after measuring the inner diameter of the artery and vein, the inner diameter of the first vascular substitute is chosen to be 90% to 100% of the inner diameter of the artery, and the inner diameter of the second vascular substitute is chosen to be 90% to 100% of the inner diameter of the vein. A tapered transition section is provided at both ends of each vascular substitute, with a length of twice the inner diameter of the vascular substitute, to reduce turbulence during blood flow. The design of the tapered transition section is simulated by finite element analysis under different blood flow velocities to adjust its length and angle, so that the turbulence intensity is less than 5% when the blood flow velocity is 0.2 meters per second. The surface smoothness of the tapered transition section is checked by scanning electron microscopy to ensure that there are no microscopic defects that may cause thrombosis. In actual application, the length and angle of the tapered transition section are personalized according to the inner diameter of the patient's blood vessels and blood flow velocity to ensure the best blood flow effect. The implantation position of the infusion device is optimized after obtaining the patient's anatomical structure data through three-dimensional imaging technology. A digital model containing bone, muscle and blood vessel distribution is constructed, and candidate implantation areas are set in the model. The candidate areas need to meet the requirements of being no more than 5 centimeters away from the entrance of the artery or vein and being located in the range of 1 centimeter to 2 centimeters in subcutaneous tissue depth. Based on the candidate areas, a surgical difficulty score is calculated for each area, with factors including surgical incision length, operation space size and postoperative recovery time. The area with the lowest surgical difficulty score is finally selected as the implantation position, and an accurate implantation path is generated through computer-aided design software. Before actual surgery, virtual reality technology is used to simulate and verify the surgical path to ensure the safety and accuracy of the implantation process. During the surgery, the skin is first cut at the selected implantation position through minimally invasive surgery technology, and then the infusion device is fixed in place through subcutaneous tunneling technology. The fixation of the infusion device is achieved through double fixation of medical glue and suture line to ensure that it does not shift after surgery.

[0019] The stability test of the key connection points is an important part of the system, and the test objects include the connection between the first vascular substitute and the artery and the connection between the second vascular substitute and the vein. Dynamic pressure is applied at these connection points, with a pressure range of 80 to 120 millimeters of mercury and a duration of 24 hours. The pressure change and displacement data at the key connection points are recorded to analyze their sealing performance and tensile resistance. After the dynamic pressure test is completed, the key connection points are examined under a microscope to ensure that there are no cracks or material deformation. According to the test results, the design parameters of the connection end are adjusted, including increasing the length of the connection end or optimizing the surface roughness of the connection end, until the stability requirements are met. In actual application, the design parameters of the connection end are personalized according to the patient's blood vessel size and hemodynamic characteristics to ensure the best connection effect.

[0020] In actual use, the patient needs to undergo regular hemodialysis treatment. Before treatment, medical staff punctures the septum of the infusion device through a coreless needle to lead the blood out of the body for dialysis. Due to the specific microstructure designed on the surface of the septum, stress concentration is effectively dispersed during the puncture process, reducing damage to the septum. The antibacterial coating on the surface of the septum further reduces the risk of infection, ensuring the safety of the treatment process. The blood flows from the artery to the dialysis equipment through the first vascular substitute, and then flows back to the vein through the second vascular substitute after dialysis. The two vascular substitutes are not connected to each other in the body, ensuring the one-way flow of blood from the artery to the vein. The design of the conical transition section reduces the turbulence phenomenon during blood flow, reducing the risk of thrombosis. After treatment, the coreless needle is pulled out, and the septum automatically closes to prevent blood leakage. The entire treatment process is safe and reliable, significantly improving the stability and safety of the vascular access during hemodialysis.

[0021] In this embodiment, the connection relationship, position relationship and mutual cooperation relationship between all parts are strictly designed and tested to ensure that the overall performance of the system reaches the optimum. Through the above specific embodiments, the technical solutions of the present application are fully disclosed, so that those skilled in the art can implement the technology according to the content of the specification, meeting the requirements of Article 26, paragraph 3 of the Chinese Patent Law.

[0022] In order to better enable those skilled in the relevant art to fully understand and implement the present application, the following further supplements the specific implementation principles of the present application in conjunction with a specific application scenario.

[0023] In actual operation, first, the anatomical structure data of the patient is obtained through a three-dimensional imaging device, and the data is imported into a computer-aided design software to generate a digital model containing bones, muscles and blood vessel distribution. According to the model, a candidate implantation area is set, which needs to meet the distance from the arterial or venous entrance not more than 5 centimeters and located in the range of subcutaneous tissue depth of 1 centimeter to 2 centimeters. Based on the candidate area, the surgical difficulty score of each area is calculated, and the scoring factors include surgical incision length, operation space size and postoperative recovery time. Finally, the area with the lowest surgical difficulty score is selected as the implantation position of the infusion device, and the virtual reality technology is used to simulate and verify the surgical path to ensure the safety and accuracy of the implantation process. Subsequently, the skin is cut at the selected implantation position through minimally invasive surgery technology, and the infusion device is fixed in place using subcutaneous tunneling technology. The fixation of the infusion device is fixed by medical glue and suture line to prevent postoperative displacement.

[0024] Next, one end of the first section of vascular substitute is connected to the artery through surgical operation, and the other end is connected to the arterial end infusion device through subcutaneous tunneling technique; one end of the second section of vascular substitute is connected to the vein through surgical operation, and the other end is connected to the venous end infusion device through subcutaneous tunneling technique. The two sections of vascular substitute are not connected to each other in the body, thereby ensuring the one-way flow of blood from the artery to the vein. During the connection process, a tapered transition section is provided at both ends of each section of vascular substitute, the length of the tapered transition section is twice the inner diameter of the vascular substitute, which is used to reduce the turbulence phenomenon during blood flow. The length and angle of the tapered transition section are adjusted through finite element analysis, so that the turbulence intensity is less than 5% when the blood flow velocity is 0.2 meters per second. The surface smoothness of the tapered transition section is checked by scanning electron microscope to ensure that there is no micro defect that may cause thrombosis. Dynamic pressure test is applied at the key connection points, the test objects include the connection between the first section of vascular substitute and the artery and the connection between the second section of vascular substitute and the vein. The dynamic pressure range is set to 80 mmHg to 120 mmHg, and the duration is 24 hours. The pressure change and displacement data at the key connection points are recorded, and the sealing performance and tensile resistance are analyzed. After the dynamic pressure test is completed, the key connection points are examined under a microscope to ensure that there are no cracks or material deformation. If deficiencies are found in the connection end, improvements are made by increasing the length of the connection end or optimizing the surface roughness of the connection end until the stability requirements are met. After the above steps are completed, the diaphragm assembly is installed inside the infusion device. The diaphragm is made of a high-elasticity and biocompatible material, and the thickness is set to be between 0.8 mm and 1.2 mm. The surface of the diaphragm is designed with specific microstructures, which are composed of groove arrays with a diameter of 50-100 microns, which can disperse the stress concentration during puncture, thereby prolonging the service life of the diaphragm. The surface of the diaphragm also undergoes antibacterial treatment, and the coating material is a silver ion-containing compound, with a coating thickness of 0.05-0.1 microns. The preparation process of the antibacterial coating includes spraying the diaphragm with an antibacterial solution and drying it in a sterile environment for 2 hours, with an environmental humidity of 50%. Antibacterial performance tests show that the coating can effectively inhibit the growth of common pathogenic bacteria within 24 hours.

[0025] In actual use, medical staff punctures the septum of the coreless needle puncture infusion device to lead the blood out of the body for dialysis. Due to the specific microstructure designed on the surface of the septum, the stress concentration is effectively dispersed during the puncture process, reducing the damage to the septum. The antibacterial coating on the surface of the septum further reduces the risk of infection, ensuring the safety of the treatment process. The blood flows from the artery to the dialysis equipment through the first section of blood vessel substitute, and then flows back to the vein through the second section of blood vessel substitute after dialysis treatment. The two sections of blood vessel substitutes are not connected to each other in the body, ensuring the one-way flow of blood from the artery to the vein. The design of the conical transition section reduces the turbulence phenomenon during blood flow, reducing the risk of thrombosis. After treatment, the coreless needle is pulled out, and the septum is automatically closed to prevent blood leakage.

[0026] The entire system is optimized through strict inner diameter matching and conical transition section, ensuring the stability of blood flow. The long-term performance of the antibacterial coating is tested by a culture medium simulating the human body environment, and the test results show that the antibacterial coating can maintain more than 90% of the bacterial growth inhibition rate within 7 days. Through the above steps and principles, the stability and safety of the vascular access during hemodialysis are realized, and the reliability of long-term use is significantly improved.

[0027] The contents not described in detail in the specification are all prior art known to those skilled in the art, and the model parameters of each device are not specifically limited, and conventional equipment can be used. In the technical solution, the electric control elements not mentioned belong to the prior art, so they are not shown in the figure, and will not be described here.

[0028] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A percutaneous arteriovenous split artificial vascular system for hemodialysis, characterized by, The application comprises the following components and steps: two infusion ports are set, an arterial infusion port and a venous infusion port, each of which is completely implanted subcutaneously and contains a septum for being punctured by a coreless needle to connect a dialysis pipeline; two independent artificial blood vessels are set, one end of the first artificial blood vessel is connected with an artery, the other end is connected with the arterial infusion port, one end of the second artificial blood vessel is connected with a vein, the other end is connected with the venous infusion port, and the two artificial blood vessels are not connected with each other in the body; during dialysis, the septum of the arterial infusion port is punctured by the coreless needle, the blood in the arterial infusion port is led out and transported to a dialyzer through the dialysis pipeline for purification treatment; the purified blood is transported to the venous infusion port through the dialysis pipeline and injected into the venous infusion port through the coreless needle, and then flows into the second artificial blood vessel and finally returns to the vein; the above process ensures that the blood flows unidirectionally from the artery to the vein through the split artificial blood vessel system, and the hemodialysis operation is completed.

2. The percutaneous arteriovenous split artificial vascular system for hemodialysis according to claim 1, characterized by, The setting of the two independent artificial blood vessels comprises the following steps: a first artificial blood vessel is selected, which is made of a polymer with biocompatibility and anticoagulant properties, one end of the first artificial blood vessel is connected with the artery through surgical operation, and the other end is connected with the arterial infusion port through subcutaneous tunneling technology; a second artificial blood vessel is selected, which is also made of a polymer with biocompatibility and anticoagulant properties, one end of the second artificial blood vessel is connected with the vein through surgical operation, and the other end is connected with the venous infusion port through subcutaneous tunneling technology; during the connection of the two artificial blood vessels, the inner diameter of each artificial blood vessel is ensured to match the inner diameter of the corresponding blood vessel to maintain the stability of blood flow; the outer surface of the two artificial blood vessels is treated with an antibacterial coating to reduce the risk of postoperative infection; after the connection of the artificial blood vessels is completed, the patency and sealing of the two artificial blood vessels are confirmed by ultrasonic detection.

3. The percutaneous arteriovenous split artificial vascular system for hemodialysis according to claim 2, characterized by The matching of the inner diameter of each artificial blood vessel with the inner diameter of the corresponding blood vessel comprises the following steps: The inner diameters of the artery and the vein are measured, the inner diameter of the artery is recorded as a first size value, and the inner diameter of the vein is recorded as a second size value; the inner diameter of the first artificial blood vessel is selected to be 90% to 100% of the first size value, and the inner diameter of the second artificial blood vessel is selected to be 90% to 100% of the second size value; a tapered transition section is arranged at each end of the artificial blood vessel, the length of the tapered transition section is twice the inner diameter of the artificial blood vessel, so as to reduce the turbulence phenomenon during blood flow; the blood flow state after the matching of the inner diameter of the artificial blood vessel with the inner diameter of the corresponding blood vessel is verified by fluid mechanics simulation, so as to ensure that the blood flow rate and pressure distribution are uniform; after the matching is completed, the smoothness of the inner wall of the artificial blood vessel is checked using a microscope, so as to ensure that there is no defect that may cause thrombosis.

4. The percutaneous AV split artificial vascular system for hemodialysis according to claim 3, characterized by, The blood flow state after matching the inner diameter of the artificial blood vessel with the corresponding blood vessel is verified by a fluid mechanics simulation, including the following steps: constructing a three-dimensional geometric model of an artery, a vein, and two segments of an artificial blood vessel, including the detailed structure of the tapered transition section; setting the physical property parameters of the blood, including a density of 1050 kilograms per cubic meter and a viscosity of 0.0035 Pascal seconds; applying boundary conditions in the model, setting the blood flow rate at the artery inlet to be 0.2 meters per second and the pressure at the vein outlet to be zero; running the fluid mechanics simulation software, analyzing the blood flow rate distribution and pressure distribution in the artificial blood vessel; adjusting the inner diameter of the artificial blood vessel or the length of the tapered transition section according to the simulation results until the blood flow state meets the preset standard.

5. The percutaneous AV split artificial vascular system for hemodialysis according to claim 1, characterized in that, The septum design of the arterial end infusion port and the venous end infusion port includes the following steps: selecting a septum material that is high in elasticity and biocompatible, such as silicone, with a thickness of 0.8 to 1.2 millimeters to ensure sealing and durability during core needle puncture; performing microstructure treatment on the surface of the septum to form a groove array with a diameter of 50 to 100 microns to reduce the risk of tearing the septum material during puncture.

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