Solid composite pressure wire

Abstract

The application discloses a solid composite structure pressure guide wire, which comprises a guide wire body, a plurality of pressure sensing units and a conductive film. The guide wire body is of a solid structure, and a helical groove is formed in the surface of the guide wire body. A plurality of mounting grooves are arranged at intervals on the helical groove. The plurality of pressure sensing units are embedded in the mounting grooves. The conductive film is attached to the helical groove, electrically connected with the pressure sensing units, and extends to the tail of the guide wire body to be connected with an operating handle at one end. The solid structure avoids the problem of excessive material removal caused by accommodating sensors in traditional hollow lumen guide wires. Compared with the existing hollow guide wire, the structure can complete the pressure measurement of multiple points in the blood vessel at one time, avoids the error accumulation caused by multiple zero calibration operations, further shortens the surgical procedure, and reduces the risk of endothelial injury in the blood vessel caused by repeated operations.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a pressure guide wire with solid composite structure. BACKGROUND

[0002] As a typical representative, the fractional flow reserve (FFR) technology measures the average pressure (Pd) in the distal coronary artery of the stenosis lesion and the average pressure (Pa) in the aorta at the coronary artery opening through an interventional pressure guide wire or pressure microcatheter system, establishes a pressure gradient ratio, and quantitatively evaluates the degree of influence of stenosis on hemodynamics. This technology not only can accurately determine whether there is functional ischemia in the coronary vessel, but also can accurately locate the ischemic responsible lesion, providing key decision-making basis for the accurate placement of stents in percutaneous coronary intervention (PCI), and has become an internationally recognized standard for guiding PCI surgery.

[0003] However, the existing pressure guide wire adopts a hollow lumen structure at the end to accommodate the pressure or temperature sensor, but the lumen space directly limits the size of the sensor (constrained by the size of the guide wire), not only restricting the miniaturization development of the sensor, but also significantly increasing the processing cost. More importantly, the lumen structure is difficult to integrate multiple sensors, and if multiple sensors are needed, the lumen size must be expanded, but this will reduce the mechanical properties of the distal end of the guide wire - the axial stiffness decreases and the longitudinal flexibility weakens, directly affecting the maneuverability of the guide wire in complex coronary artery anatomy. Therefore, the existing products generally adopt a single-point measurement scheme, which requires two zero-calibration operations to complete relative pressure detection, not only increasing the complexity of the surgical procedure, but also causing error accumulation due to multiple measurements, affecting the accuracy of FFR evaluation.

[0004] Therefore, it is necessary to provide a pressure guide wire with solid composite structure to solve the above technical problems. SUMMARY

[0005] The present application overcomes the shortcomings of the prior art and provides a pressure guide wire with solid composite structure, breaking through the technical shackles of the existing hollow lumen structure, achieving multi-parameter integrated measurement under the premise of ensuring the mechanical properties of the guide wire, thereby improving the efficiency and accuracy of FFR detection and promoting the further development of cardiac interventional diagnosis and treatment technology.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a pressure guide wire with solid composite structure, comprising:

[0007] A guide wire body, the guide wire body is of solid structure, a helical groove is formed on the surface of the guide wire body, and a plurality of mounting grooves are arranged on the helical groove at intervals;

[0008] An imaging spring is arranged at the head of the guide wire body.

[0009] a plurality of pressure sensing units embedded in the installation groove;

[0010] a conductive film attached to the spiral groove and electrically connected to the pressure sensing unit, and one end of the conductive film extending to the tail of the guide wire body and connected to the operating handle; and

[0011] a protective layer covering the outer surface of the guide wire body and the conductive film;

[0012] The pressure sensing unit comprises, from the inside to the outside, a support layer, a lower electrode, a cavity, an insulating layer and a corrugated upper electrode.

[0013] In a preferred embodiment of the present application, the number of pressure sensing units is 2-4, and adjacent pressure sensing units are spaced 10-15 mm along the guide wire axis and 150-180° along the circumference of the guide wire body.

[0014] In a preferred embodiment of the present application, the spiral groove is opened in the region 100-150 mm away from the distal end of the guide wire body, the pitch is 2-5 mm, the spiral direction is right-handed, the groove width is 500-700 μm, and the groove depth is 20-30 μm.

[0015] In a preferred embodiment of the present application, the installation groove is an elliptical long groove, the long axis direction is consistent with the guide wire axis, the long axis is 350-500 μm, the short axis is 200-300 μm, and the groove depth is 40-55 μm.

[0016] In a preferred embodiment of the present application, the support layer is a Parylene film with a thickness of 8-10 μm, the lower electrode is a magnetron sputtering Au layer with a thickness of 2-3 μm, the cavity is a closed air gap with a depth of 22-25 μm, and the insulating layer has a thickness of 3-5 μm.

[0017] In a preferred embodiment of the present application, the periodic undulating structure is a sinusoidal wave with a period of 10-20 μm, an amplitude of 3-5 μm, and a thickness of 2-3 μm, and is prepared by a magnetron sputtering Cr / Au composite layer, specifically a Cr transition layer of 5-10 nm and an Au functional layer of 2-3 μm.

[0018] A preparation method of a solid composite structure pressure guide wire, comprising the following steps:

[0019] S1, cutting the surface of the guide wire body with a femtosecond laser to form a spiral groove and a plurality of installation grooves in the spiral groove;

[0020] S2, preparing a conductive film on the surface of the polyimide film;

[0021] S3, machining a cavity and a corrugated upper electrode on the conductive film, and assembling with a prefabricated lower electrode and a support layer into a pressure sensing unit;

[0022] S4, winding the conductive film in the spiral slot, embedding the pressure sensing unit in the mounting slot, and fixing by ultraviolet curing glue;

[0023] S5, coating a protective layer on the outer surface of the guide wire body, and obtaining a pressure guide wire after curing.

[0024] In a preferred embodiment of the present application, the preparation method of the conductive film comprises the following steps:

[0025] S21, cutting a cavity on one side of the polyimide film by femtosecond laser without penetrating the polyimide film, and the residual material as an insulating layer of the pressure sensing unit;

[0026] S22, magnetron sputtering Cu / Ni composite layer on the surface of the polyimide film, and sputtering in the conductive band area and the upper electrode reserved area;

[0027] S33, according to the number of conductive bands, design a photoetching mask plate: the width of the conductive band is 40-50 μm, the distance between adjacent conductive bands is 20-40 μm, and the conductive band is U-shaped around the edge of the upper electrode reserved area;

[0028] S24, by coating photoresist, exposing and developing to define the pattern, using etching process to remove excess metal, and manufacturing a conductive film including conductive bands and upper electrode reserved areas.

[0029] In a preferred embodiment of the present application, the preparation method of the pressure sensing unit comprises the following steps:

[0030] S31, in the upper electrode reserved area, depositing a Cr / Au composite electrode layer by magnetron sputtering, then defining a periodic corrugated structure by ultraviolet lithography process, developing after exposure and removing excess metal layer by ion beam etching, and stripping the photoresist to form a corrugated upper electrode directly connected with the conductive band;

[0031] S32, preparing a support layer on the glass substrate by chemical vapor deposition process, and depositing a 2-3 μm thick Au layer on the surface of the support layer by magnetron sputtering;

[0032] S33, taking down the lower electrode containing the support layer from the glass substrate, and sealingly connecting the opening at the bottom of the cavity by ultraviolet curing glue.

[0033] In a preferred embodiment of the present application, the conductive band on the surface of the polyimide film has 3-5 strips, one of which is connected with the lower electrode as a common ground level circuit, and the remaining conductive bands are connected with corresponding corrugated upper electrodes as independent signal circuits.

[0034] The present application solves the defects in the background art and has the following advantages:

[0035] (1) The present application provides a solid composite structure pressure guide wire, the solid structure avoids the problem of excessive material removal caused by accommodating sensors in traditional hollow lumen guide wires, and the stepped subtractive design of the spiral groove and the mounting groove realizes the axial and circumferential dispersion layout of multiple sensing units while retaining more than 90% of the original radius of the guide wire body. The distal part of the guide wire has reduced bending stiffness, and the proximal end still retains the original stiffness, ensuring the passability of complex tortuous blood vessels and efficient transmission of proximal pushing force; compared with the existing hollow guide wire, which needs to expand the lumen due to the integration of a single sensor, the present structure can complete pressure measurement at multiple points in the blood vessel at one time, avoid error accumulation introduced by multiple zero calibration operations, further shorten the surgical procedure, and reduce the risk of endothelial injury in the blood vessel caused by repeated operations.

[0036] (2) The sinusoidal upper electrode of the pressure sensing unit of the present application adopts a sinusoidal periodic undulating structure, so that when the guide wire bends in the electrode sensing area, the peak area bears tensile stress and the valley area bears compressive stress. The stress directions of adjacent corrugated units are opposite, and part of the stress is offset by material elastic deformation. The concentrated load is decomposed into distributed load along the periodic direction. At the same time, the periodic undulation increases the electrode surface area and the stress transmission path length, so that the bending stress gradually decays in transmission. Further, the corrugated structure converts part of the oblique bending stress into an axial component, which is further dispersed through the spiral winding structure of the conductive film, thereby reducing the interference with the capacitance value and avoiding the occurrence of false pressure signals.

[0037] (3) The present application adopts an in-slot integration and surface flush design: the thickness of the conductive film is consistent with the depth of the spiral groove, and the thickness of the pressure sensing unit matches the depth of the mounting groove. The maximum diameter of the integrated whole is controlled to be 0.36±0.02mm. The polyimide conductive film attached in the spiral groove is seamlessly connected with the pressure sensing unit, avoiding the problem of dramatic increase in diameter caused by the protrusion of the sensor in traditional design. The guide wire of this structure can pass through coronary artery branches and cerebral blood vessels with a diameter of ≤2.5mm, meeting the needs of small blood vessel intervention.

[0038] (4) The present application forms a cavity on the polyimide film by femtosecond laser cutting, and uses the residual polyimide material as an insulating layer between the cavity and the upper electrode of the corrugated structure, avoiding the problems of bubbles or uneven thickness caused by additional coating of insulating glue, and eliminating the need for multiple processes such as sacrificial layer preparation, removal, and insulating layer deposition, thereby simplifying the production steps and improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0040] Figure 1 is a three-dimensional structure diagram of the pressure guide wire of embodiment 1 of the present application;

[0041] Figure 2 is a schematic diagram of multi-channel pressure monitoring of embodiment 1 of the present application;

[0042] Figure 3 is a cross-sectional structure diagram of the pressure sensing unit of embodiment 1 of the present application;

[0043] Figure 4 is a flow chart of the preparation method of the pressure guide wire of embodiment 2 of the present application;

[0044] Figure 5 is a schematic diagram of the distribution of the conductive belt on the conductive film of embodiment 2 of the present application;

[0045] In the figure: 100, guide wire body; 200, developing spring; 300, helical slot; 400, mounting groove; 500, pressure sensing unit; 510, support layer; 520, lower electrode; 530, cavity; 540, insulating layer; 550, corrugated upper electrode; 600, conductive film; 610, conductive belt. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0047] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0048] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0049] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] In the complex heart interventional surgery scene such as coronary artery bifurcation lesion and diffuse long segment stenosis, it is often necessary to synchronously acquire pressure data of multiple points in the blood vessel to accurately evaluate the hemodynamic changes:

[0051] Bifurcation lesion: the pressure gradient of the main branch and the side branch needs to be monitored synchronously, and single-point measurement cannot capture the dynamic pressure oscillation caused by blood flow separation at the bifurcation;

[0052] Diffuse lesion: in the case of stenosis of more than 20mm, the full-range pressure change at the lesion site needs to be obtained to reflect the functional ischemic range, and single-point data may miss the pressure recovery area, for example, the pressure rises 3-8mm after the stenosis.

[0053] However, the pressure guide wire with traditional hollow structure has significant shortcomings due to structural limitations: the single-sensor design forces the doctor to repeatedly withdraw the guide wire for segmented measurement, not only prolonging the operation time, but also introducing cumulative errors due to multiple zero calibration operations, and the hollow cavity weakens the stiffness of the guide wire, resulting in decreased maneuverability when passing through tortuous blood vessels.

[0054] The solid composite structure pressure guide wire proposed by the present application embeds 2-4 circumferentially staggered pressure sensing units in the spiral groove, and cooperates with the anti-bending interference design of the corrugated upper electrode, which can complete the full-range synchronous measurement before, during and after the lesion at one time, avoid error accumulation, and retain 90% material strength with the solid matrix, balance the flexibility of the distal end and the rigidity of the proximal end, significantly improve the passing efficiency in complex anatomical environments such as bifurcated blood vessels, and synchronously solve the clinical pain points of measurement accuracy and surgical safety.

[0055] Embodiment 1:

[0056] Figure 1 A structural schematic diagram of a solid composite structure pressure guidewire of the embodiment is shown. The pressure guidewire comprises a solid structure guidewire body 100, and a developing spring 200 welded at the distal end of the guidewire body 100.

[0057] The developing spring 200 is wound by a metal wire with developing properties, and the material is preferably a platinum group metal, and the structure is single or multi-strand. The developing spring 200 is connected with the distal end of the guidewire body 100 through a laser / tin welding process, and provides flexibility and torque control for the guidewire, and better improves the tracking of the guidewire in the blood vessel.

[0058] Further, the top end of the developing spring 200 is provided with a welding head, which is laser / plasma welded into a ball head type, greatly reducing the stimulation and damage of the guidewire to the blood vessel.

[0059] The guidewire body 100 of the embodiment is provided with a helical groove 300 on the surface, and a plurality of mounting grooves 400 are arranged on the helical groove 300 at intervals, specifically an elliptical long groove, and the long axis direction of the mounting groove 400 is consistent with the axial direction of the guidewire. The helical groove 300 is arranged on the surface of the distal end portion of the guidewire body 100, the pitch is 2-5mm, the helical direction is right-handed, which conforms to the conventional processing habit of interventional instruments, and matches the torque transmission direction when the guidewire is pushed.

[0060] The pressure guidewire of the embodiment further comprises a plurality of pressure sensing units 500 embedded in the mounting groove 400, a conductive film 600 attached to the helical groove 300, and a protective layer covering the outer surface of the guidewire body 100 and the conductive film 600. Among them, the conductive film 600 is electrically connected with the pressure sensing unit 500, and one end extends to the proximal end of the guidewire body 100 and is connected with the operating handle.

[0061] The diameter of the guidewire body 100 of the embodiment is 0.32mm, and the maximum diameter of the pressure guidewire after integrating the pressure sensing unit 500 and the protective layer is 0.36±0.02mm.

[0062] Further, the total length of the pressure guidewire is 150cm-300cm, and the optional length is generally 190cm and 300cm two specifications, to adapt to different blood vessel paths (such as radial / femoral artery approach) and lesion positions. Special cases can be customized to 182cm, 195cm and 205cm, etc., for specific anatomical structures or combined instrument operation. The length of the distal end portion is 100mm-150mm, including the sensor coverage and the helical groove 300 area.

[0063] The axial distance of adjacent installation grooves 400 is 10-15 mm, and 2-4 pressure sensing units 500 can be arranged at the distal end of the guide wire body 100, forming a multi-channel pressure guide wire structure, which can measure the blood flow pressure signals of multiple points in the axial direction of the blood vessel at one time, avoiding the measurement error and surgical risk introduced by multiple measurements of a single-channel pressure guide wire. Figure 2 As shown in the figure, at least two pressure sensing units 500 (A, B) are arranged before and after the occlusion position (stagnant plaque) in the blood vessel to measure the pressure values at different points before and after the occlusion position.

[0064] The adjacent installation grooves 400 are staggered by 150-180° along the circumference of the guide wire body 100, that is, half of the arranged pressure sensing units 500 are in the same radial plane, and the other half are in the opposite radial plane, avoiding the strength weakening caused by too many grooves in the same radial plane.

[0065] Further, the groove width of the spiral groove 300 is set to 500-700 μm, and the groove depth is set to 20-30 μm. The spiral groove 300 is completely attached to the conductive film 600, which is composed of 2-4 conductive strips 610 and insulating strips between adjacent conductive strips 610. Among them, the number of conductive strips 610 on the conductive film 600 is consistent with the number of pressure sensing units 500 arranged on the pressure guide wire, and each conductive strip 610 is connected to one pressure sensing unit 500.

[0066] The diameter of the guide wire body 100 is 320 μm, and the remaining wall thickness is 290 μm when the single groove depth is 30 μm, which retains more than 90% of the original radius, ensuring the bending strength of the distal end of the pressure guide wire.

[0067] Further, the long axis length of the installation groove 400 is 350-500 μm, matching the length of the pressure sensing unit 500 embedded therein. The short axis length of the installation groove 400 is 200-300 μm, and the groove width accounts for 20%-30% of the circumference of the guide wire body 100, ensuring uniform distribution of the remaining material in the circumferential direction and avoiding stress concentration. The groove depth of the installation groove 400 is 40-55 μm, which is slightly deeper than the spiral groove 300, avoiding the sudden change in rigidity caused by the stepped depth.

[0068] The thickness of the conductive film 600 is consistent with the depth of the spiral groove 300, and the thickness of the pressure sensing unit 500 is consistent with the depth of the installation groove 400, so that the surfaces of the conductive film 600, the pressure sensing unit 500 and the guide wire body 100 are in the same plane. Further, the process of coating a protective layer on the surface is simplified, and the problem of rapid increase in the diameter of the guide wire caused by the increase of the pressure sensing unit 500 is reduced.

[0069] By opening a spiral groove 300 on the surface of the guide wire body 100 and the cooperative design of the mounting groove 400, the guide wire distal end part realizes the flexible target of reducing the bending stiffness and the minimum bending radius ≤5mm under the premise of retaining most of the structural strength, and ensures the torque transmission efficiency and the pushing stability through the size gradient and distribution optimization. This design not only meets the passability requirement of complex blood vessels, but also avoids the strength weakening through precise control of the material removal amount, providing structural support for the safety and efficiency of interventional surgery.

[0070] Further, by embedding the pressure sensing unit 500 in the groove structure of the guide wire body 100, and filling the conductive film 600 in the spiral groove 300, the overall diameter of the pressure guide wire is finally controlled within the standard range of 0.36±0.02mm, solving the contradiction between sensor integration and miniaturization in traditional design, and providing feasibility for small vessel (such as coronary artery branch, cerebral vessel) intervention.

[0071] Further, the distal end part and the proximal end part (proximal end connected to the operation handle) of the guide wire body 100 adopt the same super-elastic nickel-titanium alloy material (composition Ti-50.8at%Ni, phase transition temperature Af=-10℃), and the stiffness gradient is precisely controlled through the pure structural subtractive design of the spiral groove 300 and the 180° circumferential staggered elliptical long groove on the distal end surface. This design significantly reduces the cross-sectional area of the material in the distal end slotted area through non-material modification, precisely reduces the bending stiffness, while retaining the high strength and torsional stiffness of the complete material in the proximal end, directly constructing a continuous stiffness gradient of "distal end super-soft - proximal end rigid", which not only ensures the flexibility of the distal end through complex tortuous blood vessels, but also guarantees the efficient transmission of pushing force and torque in the proximal end.

[0072] Further, a single pressure guide wire can be compatible with the whole process operation of passing through tortuous blood vessels, measuring multi-point pressure, and cooperating with instrument delivery, greatly reducing the need for intraoperative guide wire replacement, significantly shortening the operation time, reducing the risk of vascular endothelial injury, and effectively improving the operation efficiency and safety.

[0073] Figure 3 The pressure sensing unit 500 cross-sectional structure diagram of the present embodiment is shown. The pressure sensing unit 500 is prepared by MEMS microfabrication process, and the total thickness is controlled within 40-55μm, which is consistent with the depth of the mounting groove 400. Each layer includes, from inside to outside: support layer 510, lower electrode 520, cavity 530, corrugated upper electrode 550, and insulating layer 540 between corrugated upper electrode 550 and cavity 530.

[0074] The working principle of the pressure sensing unit 500 is as follows: when the blood flow pressure in the blood vessel is applied vertically to the corrugated upper electrode 550, the pressure causes the corrugated upper electrode 550 to elastically deform in the direction of the lower cavity 530, thereby reducing the distance between the corrugated upper electrode 550 and the lower electrode 520. According to the parallel-plate capacitance calculation relationship , the reduction of the electrode spacing d will cause the increase of the capacitance value C. Finally, the capacitance change is converted into a readable electrical signal output through the electrode lead end and the wiring connection, achieving effective monitoring of the blood flow pressure.

[0075] The pressure sensing unit 500 of the embodiment is composed as follows:

[0076] The support layer 510 is a uniform Parylene film prepared by a chemical vapor deposition process, and is arranged on the bottom surface of the mounting groove 400 with a thickness of 8-10 μm. When the thickness of the Parylene film is greater than 5 μm, a dense and uniform film state is presented, and when the thickness is less than 5 μm, pinholes are easily generated, and too thin thickness will cause the problem of "poor step coverage" of the lower electrode 520 during deposition. Further, the Parylene film used for the support layer 510 is an insulating material, which can effectively isolate the electrical signal of the guide wire main body 100 and the lower electrode 520.

[0077] The lower electrode 520 is an Au layer deposited on the surface of the support layer 510 by a magnetron sputtering process, with a thickness of 2-3 μm. If the thickness of the lower electrode 520 is too thick, stress cracking is easily generated, which is not conducive to the progress of the distal part of the pressure guide wire in the tortuous blood vessel. It should be noted that the lower electrode 520 is the fixed plate of the pressure sensing unit 500, and together with the corrugated upper electrode 550, it forms two plates of a parallel-plate capacitor, which are isolated by air, the cavity 530 and the insulating layer 540, and form a fixed capacitance initial value in the initial state. The lower electrode 520 serves as the "ground terminal" or "reference electrode" of the capacitance loop, providing a stable position reference for the deformation of the corrugated upper electrode 550, ensuring that the pressure change only changes the plate spacing through the displacement of the upper electrode, rather than the movement of the lower electrode 520.

[0078] The cavity 530 is a closed air gap structure with a depth of 22-25 μm, located between the lower electrode 520 and the corrugated upper electrode 550. The bottom of the cavity 530 is in direct contact with the surface of the lower electrode 520, and the top is isolated from the corrugated upper electrode 550 by the insulating layer 540.

[0079] The insulating layer 540 has a thickness of 3-5 μm and completely covers the upper surface of the cavity 530. The lower surface is in contact with the air gap of the cavity 530, and the upper surface is the base of the corrugated upper electrode 550.

[0080] The corrugated upper electrode 550 has a thickness of 2-3 μm and a periodic undulating structure. Specifically, the corrugated upper electrode 550 has a sinusoidal or sawtooth wave shape, and the sinusoidal wave shape is the best design due to better stress distribution uniformity, with a period of 10-20 μm and an amplitude of 3-5 μm. The periodic undulating structure of the sinusoidal wave shape decomposes the concentrated stress into distributed loads along the periodic direction through the gradual deformation of the wave peaks and wave troughs. When the bending position of the guide wire corresponds to the area where the pressure sensing unit is located, the wave peak area bears tensile stress and the wave trough area bears compressive stress. The stress directions of adjacent corrugated units are opposite, and part of the stress is offset by the elastic deformation of the material, thereby improving the fatigue resistance of the electrode structure.

[0081] Further, the lower electrodes 520 of the plurality of pressure sensing units 500 share a conductive strip 610 as a ground electrode line, and the corrugated upper electrodes 550 are connected to independent conductive strips 610 as signal lines.

[0082] In the specific implementation of the pressure guide wire, the pressure guide wire integrated with the pressure sensing unit 500 is bent, and the bending position exactly covers the sensing area. The deformation of the cavity 530 caused by the bending stress may change the distance between the upper electrode and the lower electrode 520, resulting in a false pressure signal.

[0083] The corrugated upper electrode 550 is used in this embodiment. The wave peaks and wave troughs of the corrugation produce gradual deformation when bending, which decomposes the concentrated stress into distributed loads along the period of the corrugation. For example, when the bending radius is 5 mm, the wave peak area bears part of the tensile strain and the wave trough area bears part of the compressive strain. The stress directions of adjacent corrugated units are opposite, and part of the stress is offset by the elastic deformation of the material. In addition, the periodic undulation increases the surface area and stress transmission path length of the corrugated upper electrode 550, so that the stress gradually decays during transmission.

[0084] Further, the corrugated structure converts part of the oblique bending stress into an axial component, which is further dispersed through the spiral winding structure of the conductive film 600, thereby reducing the interference with the capacitance value and avoiding the occurrence of false pressure signals.

[0085] To ensure the safety of the pressure guide wire, a protective layer is coated on the surface of the pressure guide wire after the integrated pressure sensing unit 500 and the wound conductive film 600, which isolates the guide wire body 100 from the working environment. The protective layer is PTFE or medical-grade transparent silicone gel. The surface of the protective layer is smooth, which can significantly reduce the resistance of the guide wire when moving in the blood vessel or cavity, reduce mechanical damage to the tissue, and has electrical insulation, protecting the conductive structure integrated on the guide wire.

[0086] Embodiment 2:

[0087] Figure 4A flow chart of a preparation method of the pressure guide wire of the solid composite structure is shown. The preparation method of the pressure guide wire comprises the following steps:

[0088] In step S1, a helical groove 300 is machined along the guide wire body 100 in the axial direction by femtosecond laser cutting, and a mounting groove 400 is machined according to a predetermined position.

[0089] In step S2, a Cu / Ni composite layer is magnetron sputtered on the surface of the polyimide film, and a conductive strip 610 pattern is defined by photolithography, and the conductive strip 610 is reserved after wet etching, to obtain a conductive film 600.

[0090] In step S3, a pressure sensing unit 500 is layer-by-layer fabricated on a predetermined area of the surface of the conductive film 600, and the corrugated upper electrode 550 and the lower electrode 520 of the pressure sensing unit 500 are connected to the corresponding conductive strip 610.

[0091] In step S4, ultraviolet curing glue is coated in the helical groove 300 of the guide wire body 100, and low-modulus silicone rubber is filled in the mounting groove 400, the conductive film 600 integrated with the pressure sensing unit 500 is wound along the helical groove 300, and the pressure sensing unit 500 is embedded in the mounting groove 400, and the glue layer is cured under irradiation of ultraviolet light at 365 nm for 30-60 s.

[0092] In step S5, a protective layer is coated to cover the surface of the guide wire body 100 and the conductive film 600, to obtain the pressure guide wire.

[0093] The preparation method of the pressure guide wire significantly reduces the integration difficulty of the pressure sensing unit 500 and the flexible guide wire through the process path of planar prefabrication and three-dimensional integration, and meets the high-precision and reliability requirements of intravascular pressure monitoring.

[0094] The steps of the preparation method of the pressure guide wire will be described in detail below.

[0095] In step S1, the guide wire body 100 is made of super-elastic nickel-titanium alloy material (composition Ti-50.8at%Ni, phase transition temperature Af=-10°C), and the surface roughness is increased by electrolytic polishing to ensure the adhesion of the subsequent coating.

[0096] In this step, the helical groove 300 and the mounting groove 400 are machined by femtosecond laser. The helical groove 300 has a groove width of 400-500 μm, a groove depth of 20-30 μm, a pitch of 2-5 mm, and a right-handed helical direction. The helical groove 300 is machined by helical progressive cutting: the guide wire rotates at 100 rpm, and the laser scanning speed is 400 mm / s. The mounting groove 400 is an elliptical long groove, and the long axis of the mounting groove 400 is 350-500 μm, the short axis is 200-300 μm, and the groove depth is 40-55 μm. The mounting groove 400 is machined by layer-by-layer cutting, and the mounting groove 400 is machined to the set depth by multiple cutting.

[0097] It should be noted that the installation groove 400 is in the spiral groove 300, and the adjacent installation grooves 400 are circumferentially staggered by 150-180°, and the distance is 10-15 mm.

[0098] In step S2, the polyimide film is used as the main body of the conductive film 600. Specifically, the conductive film 600 is composed of 3-5 conductive strips 610 and insulating strips between adjacent conductive strips 610. The insulating strips, i.e., the polyimide film, not only form isolation between the conductive strips 610, but also form isolation between the conductive strips 610 and the guide wire body 100. That is, 3-5 conductive strips 610 are prepared on the surface of the polyimide film, one of which is used as a common ground line, and the remaining conductive strips 610 are used as independent signal lines. The conductive strips 610 are used to connect the pressure sensing unit 500 and extend to the proximal end of the guide wire body 100 to connect with the operating handle, realizing the electrical signal capture of the pressure sensing unit 500.

[0099] A Cu / Ni composite layer is magnetron sputtered on the surface of the polyimide film, and the conductive strip 610 pattern is defined by photolithography. After wet etching, the conductive strip 610 is retained to obtain the conductive film 600.

[0100] Figure 5 A schematic diagram of the distribution of the conductive strips 610 on the conductive film 600 of the present embodiment is shown. The preparation method of the conductive film 600 of the present embodiment includes the following steps:

[0101] In step S21, a polyimide film with a thickness of 25-30 μm and a width of 490-690 μm is selected, which is slightly smaller than the width of the spiral groove 300. A femtosecond laser is used to cut a cavity 530 on one side of the polyimide film, with a depth of 22-25 μm, without penetrating the polyimide film. The residual material serves as an insulating layer 540 of the pressure sensing unit 500.

[0102] In step S22, a Cu / Ni composite layer is magnetron sputtered on the surface of the polyimide film, and a partition sputtering mode is adopted:

[0103] In the conductive strip 610 area, the bottom layer is a 50 nm Ni layer, and the top layer is a 3-5 μm Cu layer.

[0104] In the upper electrode reserved area, only a 50 nm Ni layer is deposited.

[0105] It should be noted that the Ni bottom layer has strong chemical affinity with the polyimide substrate, which improves the adhesion through metal-polymer interface chemical bonds (Ni-O-C), and at the same time inhibits the diffusion of Cu to the substrate. The Cu top layer has high conductivity, which meets the low-loss transmission requirement of the weak signal of the pressure sensing unit 500.

[0106] Step S23, according to the number of the designed conductive strips 610, design the photoetching mask plate, the width of the conductive strips 610 is 40-50 μm, and the distance between adjacent conductive strips 610 is 20-40 μm. Moreover, the conductive strips 610 are in a "U-shaped bypass" at the edge of the upper electrode reserved area, the bypass path radius is ≥100 μm, the bypass segment length is 20 μm wider than the reserved area, and the stress concentration caused by sharp corners is avoided.

[0107] Step S24, through coating photoresist, exposing and developing to define the pattern, and then removing the excess metal by etching process, the conductive film 600 including the conductive strips 610 and the upper electrode reserved area is prepared.

[0108] In step S3, the corrugated upper electrode 550 is prepared at the upper electrode reserved area on the surface of the conductive film 600, and the lower electrode 520 and the support layer 510 made externally are spliced with the cavity 530, so as to obtain the pressure sensing unit 500.

[0109] The corrugated upper electrode 550 is on one side of the conductive strips 610, and the cavity 530 is on the side of the non-conductive strips 610. The insulating layer 540 between the corrugated upper electrode 550 and the cavity 530 has been prepared when the conductive film 600 is prepared in step S2.

[0110] The specific preparation method of the pressure sensing unit 500 includes the following steps:

[0111] Step S31, in the upper electrode reserved area, a Cr / Au composite electrode layer is deposited by magnetron sputtering, and then a periodic corrugated structure is defined by ultraviolet photoetching process: positive photoresist is spin-coated, a sinusoidal corrugated pattern with a period of 10-20 μm and an amplitude of 3-5 μm is formed by ultraviolet photoetching technology, the excess metal layer is removed by ion beam etching after exposure and development, and the corrugated upper electrode 550 directly connected with the conductive strips 610 is formed after stripping the photoresist, and the thickness is 2-3 μm.

[0112] The magnetron sputtering deposition of the Cr / Au composite electrode layer is specifically as follows: taking Cr and Au target materials with a purity of 99.99% as the source, a Cr transition layer with a thickness of 5-10 nm and an Au functional layer with a thickness of 2-3 μm are sequentially deposited in an Ar atmosphere.

[0113] Step S32, the support layer 510 is prepared on the glass substrate by chemical vapor deposition process: the glass substrate is fixed in the vacuum deposition cavity, Parylene monomer is introduced, and the gas phase polymerization is initiated at 80°C to deposit a uniform film with a thickness of 8-10 μm on the surface of the glass substrate.

[0114] An Au layer with a thickness of 2-3 μm is deposited on the surface of the support layer 510 by magnetron sputtering, and a lead area with a diameter of 60-100 μm is reserved at the edge of the lower electrode 520.

[0115] Step S33, the lower electrode 520 containing the support layer 510 is removed from the glass substrate, and is sealed and connected with the bottom opening of the cavity 530 by ultraviolet curing glue, which is actually bonded with the surface of the polyimide film, realizing the sealing of the cavity 530; wherein the size of the lower electrode 520 is larger than that of the cavity 530, and the lead area of the lower electrode 520 corresponds to the pad area of the conductive strip 610. The laser micro-hole is formed in the pad area of the conductive strip 610, the bottom of the hole corresponds to the lead area of the lower electrode 520, and copper is plated in the micro-hole to connect the lower electrode 520 with the conductive strip 610.

[0116] In this embodiment, the cavity 530 is formed on the polyimide film by femtosecond laser cutting, and the residual polyimide material is used as the insulating layer 540 between the cavity 530 and the corrugated upper electrode 550, avoiding the problems of bubbles or uneven thickness caused by additional coating of insulating glue, and saving the multiple processes of preparation, removal of the sacrificial layer, and deposition of the insulating layer 540, thereby simplifying the production steps and improving the production efficiency.

[0117] Further, the corrugated upper electrode 550 is directly bonded with the polyimide film, reducing the risk of electrode layer peeling when the pressure guide wire is bent, and the corrugated upper electrode 550 and the conductive strip 610 form a continuous conductive path by integrated photolithography and etching process, which has higher signal transmission effect than gold wire bonding connection, and is especially suitable for collecting weak capacitance signals.

[0118] Through the in-situ integrated preparation of the cavity 530, the insulating layer 540, and the corrugated upper electrode 550 on the conductive film 600, seamless integration of the sensor and the conductive carrier is realized, which has higher structural precision and reliability than the traditional separate preparation and reassembly mode, and greatly saves the manufacturing cost.

[0119] In step S4, ultraviolet curing glue is coated in the spiral groove 300 of the guide wire body 100, and low-modulus silicone rubber is filled in the mounting groove 400. The conductive film 600 integrating the pressure sensing unit 500 is wound along the spiral groove 300, and the pressure sensing unit 500 is embedded in the mounting groove 400. The glue layer is cured by irradiation with ultraviolet light of 365 nm for 30-60 s.

[0120] In step S5, PTFE or medical-grade transparent silicone gel is coated to cover the surface of the guide wire body 100 and the conductive film 600, obtaining a pressure guide wire.

[0121] In the following, different pressure guide wire samples are prepared, and bending tests are conducted to monitor the change of electrical signals and verify the influence of different structural designs (upper electrode shape, line groove type) on the electrical signal stability during the bending process of the pressure guide wire.

[0122] Sample 1:

[0123] The preparation method of the sample 1 comprises the following steps:

[0124] Step 1, a nickel-titanium alloy wire with a diameter of 0.32 mm is selected, a helical slot 300 with a slot width of 700 μm, a slot depth of 30 μm and a pitch of 5 mm is processed on a region 150 mm away from a distal end of a guide wire body 100 by a femtosecond laser, and an elliptical mounting slot 400 with a slot depth of 55 μm, a long axis of 500 μm and a short axis of 300 μm is processed at a position 30 mm away from a head end of the guide wire body 100.

[0125] Step 2, two conductive strips 610 are made on the surface of a 30 μm thick polyimide film, one is a ground electrode circuit and the other is a signal circuit, and a cavity 530 with a depth of 25 μm is cut on the polyimide film by a femtosecond laser, and the residual material is an insulating layer 540 with a thickness of 5 μm.

[0126] Step 3, a Cr / Au composite electrode layer (Cr 10 nm, Au 3 μm) is formed on the other side of the cavity 530 on the polyimide film by magnetron sputtering, a sinusoidal wave structure (period 20 μm, amplitude 5 μm) is defined by ultraviolet lithography, and ion beam etching is used for forming, in addition, the upper electrode 550 on the wave structure is connected with the signal conductive strip 610 by integrated photolithography.

[0127] Step 4, the pre-prepared lower electrode 520 with a thickness of 3 μm is bonded to the bottom of the cavity 530 by ultraviolet curing glue, and the lower electrode 520 is connected with the ground conductive strip 610 by laser microporous copper plating.

[0128] Step 5, the conductive film 600 of the integrated pressure sensing unit 500 is wound in the helical slot 300, and a PTFE protective layer is coated on the outer surface of the pressure guide wire, to obtain the sample 1.

[0129] Sample 2:

[0130] Based on the sample 1, the difference lies in that the upper electrode 550 on the wave structure is a sinusoidal wave with a period of 10 μm and an amplitude of 3 μm.

[0131] Sample 3:

[0132] Based on the sample 1, the difference lies in that the upper electrode is a flat electrode layer with a thickness of 3 μm.

[0133] Sample 4:

[0134] Based on the sample 1, the difference lies in that the conductive film 600 is attached in a straight slot with a consistent slot depth.

[0135] The pressure guide wire of samples 1 to 4 was fixed at a position 200 mm away from the distal end, and two mechanical arms were used, one fixed clamping the guide wire head end, and the other mechanical arm clamping the position variable, by changing the position of the two mechanical arms, the random position bending of the guide wire sample was realized, repeated 1000 times, the output signal of the pressure sensing unit 500 of samples 1 to 4 was monitored (analog pressure value unit: mmHg, reference pressure 0 mmHg), and the results are shown in Table 1.

[0136] Table 1. Monitoring results summary

[0137]

[0138] In the operation of coronary artery bifurcation lesions, the bifurcation lesion main branch / branch pressure gradient is often only 1-3 mmHg, and if the fluctuation amplitude is >0.5 mmHg, the FFR critical value will be misjudged, and serious errors will lead to misplacement of the branch stent; while diffuse lesions need to be determined by pressure-distance curve slope to determine the ischemic range, and linearity <0.9 will increase the detection rate of 3-8 mm pressure recovery zone after stenosis; more importantly, the number of random signal fluctuations caused by thousands of times of bending will cause false alarms, forcing the operator to repeatedly verify, prolonging the operation time and increasing the risk of vascular injury.

[0139] As can be seen from the above table, the signal fluctuation of sample 1 is the smallest, and the linearity is close to the ideal value. The corrugated upper electrode 550 of sample 1 has a large period and high amplitude sinusoidal structure, which disperses the bending stress into distributed load along the periodic direction through the progressive deformation of the wave crest / valley, reduces the false change of capacitance caused by the deformation of the cavity 530, and the spiral winding of the conductive film 600 converts the axial bending stress into a circumferential component, further reducing the stress concentration in the sensing unit area.

[0140] The stress of sample 3 is concentrated in the local area of the electrode, which directly leads to the compression / stretching of the cavity 530, and the dramatic change of the capacitance value (false pressure signal), so the signal fluctuation amplitude of sample 3 is the largest, and the fluctuation times reach 79 times. The fluctuation amplitude of sample 4 is 4.2 times that of sample 1, and the fluctuation times also reach 53 times, which is because the conductive film 600 is attached along a straight line, and the stress is directly transmitted to the sensing unit along the axial direction when bending, while the "spiral winding" of the spiral slot 300 can disperse the stress through circumferential rotation.

[0141] The prepared solid composite structure pressure guide wire of the application avoids the problem of excessive material removal of traditional hollow lumen guide wire caused by accommodating sensors, and realizes the axial and circumferential dispersion layout of multiple sensing units while reserving more than 90% of the original radius of the guide wire body through the stepped subtractive design of the spiral groove and the mounting groove. The distal end of the guide wire is reduced in bending stiffness, and the proximal end still retains the original stiffness, ensuring the passability of complex tortuous blood vessels and efficient transmission of proximal pushing force; compared with the existing hollow guide wire, which needs to expand the lumen due to the integration of a single sensor, the structure can complete the pressure measurement of multiple points in the blood vessel at one time, avoid the error accumulation introduced by multiple zero calibration operations, further shorten the surgical procedure, and reduce the risk of endothelial injury in the blood vessel caused by repeated operations.

[0142] Further, the corrugated upper electrode of the pressure sensing unit adopts a sinusoidal periodic undulating structure, so that when the guide wire is bent in the electrode sensing area, the wave crest area bears tensile stress and the wave trough area bears compressive stress, the stress directions of adjacent corrugated units are opposite, and part of the stress is offset by material elastic deformation, thereby decomposing the concentrated load into distributed load along the periodic direction; at the same time, the periodic undulation increases the electrode surface area and the stress transmission path length, so that the bending stress gradually attenuates during propagation. Further, the corrugated structure converts part of the oblique bending stress into an axial component, and the axial component is further dispersed through the spiral winding structure of the conductive film, thereby reducing the interference with the capacitance value and avoiding the occurrence of false pressure signals.

[0143] The above is based on the ideal embodiment of the application, and through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the application. The technical scope of the application is not limited to the contents of the specification, and must be determined according to the scope of the claims.

Claims

1. A solid composite pressure wire, characterized by, The utility model relates to a pressure guide wire, comprising: a guide wire body with a solid structure, a helical groove is formed on the surface of the guide wire body, and a plurality of mounting grooves are arranged at intervals on the helical groove; a developing spring is arranged at the head of the guide wire body; a plurality of pressure sensing units are embedded in the mounting grooves, and adjacent pressure sensing units are staggered by 150-180 degrees along the circumferential direction of the guide wire body; a conductive film is attached to the helical groove and electrically connected to the pressure sensing units, and one end of the conductive film extends to the tail of the guide wire body and is connected to the operating handle; and a protective layer is coated on the outer surface of the guide wire body and the conductive film; wherein the pressure sensing unit comprises, from inside to outside, a support layer, a lower electrode, a cavity, an insulating layer and a corrugated upper electrode; the corrugated upper electrode has a periodic undulating structure, and the periodic undulating structure is a sinusoidal wave.

2. A solid composite pressure guide wire according to claim 1, wherein: The number of pressure sensing units is 2-4, and adjacent pressure sensing units are spaced apart by 10-15 mm along the axial direction of the guide wire.

3. A solid composite structural pressure guidewire as in claim 1, wherein: The helical groove is formed in the region 100-150 mm away from the distal end of the guide wire body, the pitch is 2-5 mm, the helical direction is right-handed, the groove width is 500-700 μm, and the groove depth is 20-30 μm.

4. A solid composite structural pressure guidewire as in claim 1, wherein: The mounting groove is an oval long groove, the long axis direction is consistent with the axial direction of the guide wire, the long axis is 350-500 μm, the short axis is 200-300 μm, and the groove depth is 40-55 μm.

5. A solid composite structural pressure guidewire as in claim 1, wherein: The support layer is a Parylene film with a thickness of 8-10 μm; the lower electrode is a magnetron sputtering Au layer with a thickness of 2-3 μm; the cavity is a closed air gap with a depth of 22-25 μm; and the insulating layer has a thickness of 3-5 μm.

6. A solid composite structural pressure guidewire as in claim 1, wherein: The parameters of the sinusoidal wave are as follows: period 10-20 μm, amplitude 3-5 μm, thickness 2-3 μm, prepared by magnetron sputtering Cr / Au composite layer, specifically Cr transition layer 5-10 nm and Au functional layer 2-3 μm.

7. A method for the production of a solid composite pressure wire based on a solid composite pressure wire according to any one of claims 1 to 6, characterized in that The steps include: S1, cutting the surface of the guide wire body with femtosecond laser to form a helical groove and a plurality of mounting grooves in the helical groove; S2, preparing a conductive strip on the surface of the polyimide film to form a conductive film; S3, processing a cavity and a corrugated upper electrode on the conductive film, and assembling the lower electrode and the support layer to form a pressure sensing unit; S4, winding the conductive film in the helical groove, embedding the pressure sensing unit in the mounting groove, and fixing it with ultraviolet curing glue; S5, coating a protective layer on the outer surface of the guide wire body, and obtaining a pressure guide wire after curing.

8. A method of making a solid composite structure pressure guidewire according to claim 7, wherein: The preparation method of the conductive film includes the following steps: S21, cutting a cavity on one side of the polyimide film with femtosecond laser without penetrating the polyimide film, and the residual material is used as an insulating layer of the pressure sensing unit; S22, magnetron sputtering Cu / Ni composite layer on the surface of the polyimide film, and sputtering in the conductive strip area and the upper electrode reserved area; S33, according to the designed number of conductive strips, design the photoetching mask: the width of the conductive strip is 40-50 μm, the distance between adjacent conductive strips is 20-40 μm, and the conductive strip is U-shaped around the edge of the upper electrode reserved area. S24, by coating photoresist, exposure and development define pattern, using etching process to remove excess metal, made of conductive film including conductive strip and the upper electrode reserved area.

9. A method of making a solid composite structure pressure guidewire according to claim 8, wherein: The preparation method of the pressure sensing unit comprises the following steps: S31, in the upper electrode reserved area, a Cr / Au composite electrode layer is deposited by magnetron sputtering, and then a periodic corrugated structure is defined by using a UV lithography process; after exposure and development, the excess metal layer is removed by ion beam etching; and after stripping the photoresist, the corrugated upper electrode directly connected with the conductive strip is formed; S32, a support layer is prepared on the glass substrate by using a chemical vapor deposition process, and a Au layer with a thickness of 2-3 μm is deposited on the surface of the support layer by magnetron sputtering; S33, the lower electrode containing the support layer is removed from the glass substrate, and is sealed and connected with the bottom opening of the cavity by using UV curing adhesive.

10. The method of claim 8, wherein: The conductive strips on the surface of the polyimide film are 3-5, one of which is connected with the lower electrode as a common ground line, and the remaining conductive strips are connected with corresponding corrugated upper electrodes as independent signal lines.

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