An integrated flapped duct and a method of manufacturing the same

Abstract

This invention discloses an integrated valved conduit and its preparation method, relating to the field of medical device technology. It aims to solve the problems of traditional valved conduits, such as cumbersome suturing during surgery, risks of tearing and thrombosis, and insufficient adaptability. The integrated valved conduit consists of a leaflet and a conduit, which are sintered together, eliminating the need for sutures and effectively avoiding the risks of reflux and thrombosis caused by suture gaps. A metal shape memory alloy stent is embedded within the conduit wall, providing support to stabilize hemodynamics and prevent conduit collapse, while also enabling endovascular delivery. It is suitable for both open surgical and endovascular implantation methods, and can be used for valved conduit replacement in areas such as the pulmonary artery and deep veins of the lower extremities, restoring damaged valve function.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to an integrated valved conduit and its preparation method. Background Technology

[0002] Congenital heart disease (CHD) is a condition where a child is born with a structural abnormality in their heart. It is reported that CHD accounts for approximately one-third of all birth defects, affecting over 13.3 million children worldwide. It is estimated that one-fifth of CHD patients have pulmonary valve (PV) or right ventricular outflow tract (RVOT) dysfunction. Surgical repair within the first month after birth is currently the gold standard of treatment, with a high survival rate (98-100%) after initial complete repair. Currently, over 80% of CHD patients survive to age 35 after surgery, and 70% of those surviving to age 18 survive to age 70. Clinical data shows that approximately 60% of Tetralogy of Fallot patients require further intervention within 10 years after surgery, and 20% of Ross surgery patients require a second surgery due to RVOT failure. Right ventricular outflow tract (RVOT) reconstruction is a crucial factor in determining prognosis, and the pulmonary valved conduit is a key instrument in this procedure. Since Ross first used an allogeneic transplant valve catheter in 1966, several types of RVOT catheters have been developed.

[0003] For severe deep vein valve insufficiency, conventional treatments include valve repair and venous circumference reduction, but these two treatments are not very effective. Valved conduit replacement therapy is one of the promising treatments, but there are no marketed products available.

[0004] Currently, the most commonly used valved conduits can be broadly classified into four categories: allogeneic grafts, xenograft valved catheters, porcine valve catheters, and ePTFE valved conduits. The core challenges lie in three main areas: complex fabrication techniques, poor material biocompatibility, and poor hemodynamic performance.

[0005] The most common clinically used ePTFE tricuspid valve still requires manual suturing to achieve valve-conduit connection, which carries risks of leaflet misalignment and regurgitation. Preparation techniques limit its clinical adoption: current manual suturing techniques rely on surgeon experience. Even with dual template assistance (template A for positioning suture points, template B for cutting leaflets), preparation still takes 30-40 minutes. Furthermore, inconsistent product quality due to different surgeons' operations (pass rate only 78%) necessitates manual suturing of the valve and conduit. Valve-supported conduits have weak support, making them prone to hemodynamic instability. The conduit sways with the heartbeat, potentially causing suture tearing and gaps, increasing the risk of regurgitation and thrombosis (occurrence rate approximately 8%). This makes it difficult to promote in primary hospitals, further exacerbating the regional imbalance in RVOT reconstruction surgery.

[0006] For example, Chinese patent application CN2018113916315, filed on November 21, 2018 and published on April 5, 2019, discloses a valved conduit and a method for manufacturing a valved conduit. This patented valved conduit design includes a tubular body and at least three leaflets sewn onto the inner side. The upper edge of the leaflets is separated from the tubular body, and the side edges are sewn together to form a valve pocket. During manufacturing, the radius of the tubular body and the size of the leaflets are determined according to factors such as age and weight. The tubular body is formed by cutting, sewing the leaflets, and sewing the side edges. Although a standardized design using formulas ensures basic adaptability, the reliance on manual sewing makes it prone to suture gaps leading to regurgitation. Furthermore, the leaflet size is designed solely based on the tube diameter, making it impossible to personalize adjustments for individual patient hemodynamic parameters.

[0007] For example, Chinese patent application CN201910651676X, filed on July 18, 2019 and published on September 17, 2019, discloses a valved conduit and its preparation method. This patent proposes a valved conduit comprising a distal valved structure and a proximal vessel. The distal end is constructed using ePTFE tubing inversion and adhesive thermal fusion to create a U-shaped three-valve structure. The conduit is then extended using a mold under heat pressure to form the valve sinus. Adjacent leaflet roots require suturing at 1 / 10 of its diameter length. The preparation process involves cumbersome steps such as material preparation, tubing inversion fusion, mold extension, and end joining. Although the mold improves some structural stability, the leaflets and conduit are still prepared separately, the leaflet parameters are fixed, and the roots still require suturing, making the preparation cumbersome. Furthermore, ePTFE material generally has poor biocompatibility, making it difficult to adapt to the diverse anatomical and hemodynamic characteristics of patients.

[0008] For example, Chinese patent application CN2023230502092, filed on November 10, 2023, and published on September 27, 2024, discloses a utility model patent for aortic valved conduit. This utility model patent targets aortic repair, and the valved conduit consists of an artificial heart valve and an aortic conduit. The artificial heart valve includes a valve stent and artificial leaflets. The aortic conduit has two states: compressible (for easy delivery) and expanded (for support and anchoring). The conduit includes a vascular frame and a lining, and the frame is reinforced and fixed to the vascular wall through connectors (including anchoring structures). However, this patent is only applicable to the aorta, the leaflet design is standardized, and it relies on balloon or self-expanding fixation, limiting the implantation method and applicable sites, and failing to meet the needs of other sites such as the pulmonary artery and individualized patient requirements.

[0009] For example, US patent application US7320705B2 discloses a bileaflet pulmonary artery heart valve and its preparation method. Using fluoropolymers such as PTFE as raw materials, the valve is cut into elliptical pieces, incised along its short axis, and folded into a tubular structure. Finally, the flexible valve component is fixed to the infundibulum septum of the right ventricular outflow tract by manual suturing. This design has significant drawbacks: manual suturing, which relies on the surgeon's experience, is not only time-consuming but also leads to poor product consistency. Furthermore, the suture sites are exposed to blood flow, making them susceptible to tearing due to interfacial stress generated by cardiac pulsation, potentially causing regurgitation. Additionally, it can only be standardized and adapted according to a single parameter—"the short axis of the ellipse is approximately 1.5 times the diameter of the outflow tract"—making it only suitable for right ventricular outflow tract reconstruction, thus limiting its applicability.

[0010] For example, US patent application US20200113681A1 discloses an artificial valved conduit, but the preparation process is cumbersome: the conduit must first be cut into two sections, a groove must be made at the proximal end of the second section, and then the valve leaflet attachment edge must be clamped between the two conduit sections and fixed by complex sutures or fixation elements. This process relies on manual operation, which is not only inefficient, but also prone to micro-gaps at the clamping interface that can cause reflux, and the suture site is prone to material fatigue fracture due to stress concentration at the interface; personalization is limited to matching the inner diameter of the conduit with the size of the valve leaflet, the morphology of the sinus structure is fixed, and the coordination with the opening and closing movement of the valve leaflet is insufficient, making it difficult to adapt to the diverse hemodynamic needs of patients.

[0011] This technology is the first of its kind to create a sutureless, electrospun, integrated valved conduit. The preparation method is simple and solves problems such as leakage in traditional hand-sewn conduits. It can improve patient prognosis, reduce medical costs, and promote the development of cardiovascular implantable devices, and has significant clinical value and application prospects. Summary of the Invention

[0012] The purpose of this invention is to provide an integrated valved conduit and its preparation method. In this integrated valved conduit, the valve leaflets and conduit are formed into one piece through high-temperature sintering, eliminating the need for suture fixation. This solves the problems of cumbersome manual suturing during surgery, poor product consistency, easy tearing of suture sites, and the risk of reflux and thrombosis in traditional valved conduits. At the same time, through customized valve leaflet mold design, the valve leaflet morphology can be personalized according to the patient's hemodynamic characteristics, enabling the integrated valved conduit to be adapted to the replacement needs of human pulmonary artery valves and deep vein valved conduits through open surgery or endovascular intervention.

[0013] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0014] The first aspect of the present invention provides an integrated valved conduit, the integrated valved conduit comprising a valve leaf and a conduit;

[0015] The petals and the pipe are formed as one piece by sintering, without the need for stitching; the petals are two or three petals, and each petal includes a base and a free surface, with the junction between two adjacent free surfaces and the base being integrally connected to the pipe.

[0016] In this invention, the specific shape of the leaflet is not uniquely limited and can be adjusted using a mold according to the patient's hemodynamic characteristics. Typically, when the free surface of the leaflet mold is fully unfolded, it is a semi-ellipse with its minor axis halved. This semi-ellipse is defined by its major axis (a) and minor axis (b), and the focal length (c, the distance from the center to a focal point) satisfies (c...). 2 =a 2 -b 2 The eccentricity (e=c / a) determines the flatness of the ellipse (e=0 is a circle, and the closer e is to 1, the flatter it is). Different anatomical needs can be adapted by adjusting the major axis and minor axis parameters. At the same time, the valve sinus structure is formed in sync with the canal formation. Its outward convexity and size can be preset by the mold to ensure that it is adapted to the opening and closing movement of the valve leaflets and reduce blood flow turbulence.

[0017] Preferably, when the petal leaflet is bilobed, the petal leaflet includes two free surfaces; when the petal leaflet is trilobed, the petal leaflet includes three free surfaces.

[0018] Preferably, the pipe includes a metal support.

[0019] Preferably, the metal support is made of shape memory alloy.

[0020] A second aspect of the present invention provides a method for preparing an integral valved conduit, the method comprising the following steps:

[0021] (1) Dissolve the polymer in an organic solvent to obtain a polymer solution;

[0022] (2) A first thin film is formed on the surface of a cylindrical metal receiver, and one end is cut as a free edge;

[0023] (3) Fit one end of the leaflet mold onto the free edge end of the first film, and then form a second film on the surface of the leaflet mold and the surface of the first film with a polymer solution;

[0024] (4) The metal receiver covered with the first and second thin films is sintered. The first and second thin films are completely fused by utilizing the difference in melting points of different polymers (at least one polymer has a melting point within the sintering temperature range). During the sintering process, the leaflet mold avoids the accidental fusion of the first thin film (leaflet) and the second thin film (channel). The bottom of the leaflet base and the junction of adjacent free surfaces are sintered together with the second thin film by external extrusion. The valve sinus structure is shaped as each layer of material is fused. Finally, the excess material is removed by laser cutting and the leaflet mold is taken out to obtain the integrated valve-type channel.

[0025] Preferably, after step (3), the method further includes: fitting a metal support onto the surface of the second film layer, and continuing to form a third film layer on the surface of the metal support.

[0026] Preferably, in step (1), the polymer is selected from at least one of polyurethane, polycaprolactone, polystyrene, polytetrafluoroethylene, and polyethylene glycol. Specifically, a single polymer or a blend of multiple polymers can be selected according to the mechanical properties (such as flexibility and support) and biocompatibility requirements of the valved conduit. For example, a blend of polyurethane and polycaprolactone can take into account the differences in elasticity and sintering melting point.

[0027] Preferably, in step (3), the leaflet mold includes a tubular body and an arc-shaped protrusion (i.e., the free surface of the leaflet mold) disposed at one end of the tubular body and spaced apart.

[0028] Preferably, the arc-shaped protrusion of the leaflet mold is fitted onto the free edge end of the first film, and the connection between the arc-shaped protrusion and the tubular body is aligned with the free edge.

[0029] Preferably, in step (3), the inner diameter of the leaf mold is 8~30mm.

[0030] Preferably, in step (3), there is at least one arc-shaped protrusion.

[0031] In this invention, the connection between the leaflet and the pipe is achieved through sintering to achieve a tight fit without gaps, which can effectively reduce the risk of backflow.

[0032] Preferably, in steps (2) and (3), the formation methods of the first thin film (leaflet layer), the second thin film (inner duct layer) and the third thin film (outer duct layer) are selected from any one of electrospinning, 3D printing, spin coating, dip coating, spraying and casting, respectively; wherein when electrospinning is used, the film thickness in the convex region of the valve sinus can be made uniform by adjusting the spinning voltage, flow rate and receiving distance, so as to avoid local thinning that leads to insufficient structural strength.

[0033] Preferably, in step (4), the sintering temperature can be adjusted according to the melting point of the selected polymer (usually 50~150℃), and the holding time is 0.01~2h to ensure that the materials of each layer are tightly fused and the integrity of the metal support, leaflet and pipe structure is not damaged; during the cutting process, high-precision laser cutting is used for the edge of the valve sinus to avoid the valve opening and closing sealing performance affected by the cutting error.

[0034] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0035] (1) The integrated valved conduit of the present invention adopts an integrated sutureless design, which solves the defects of traditional separate preparation by suturing or heat fusion: by using film-forming technology and valve leaflet mold-assisted design, a brand-new preparation process is developed, which realizes the full integration of valve leaflet and conduit through sintering, eliminating the need for manual suturing. This completely solves the problems of traditional valved conduits (such as ePTFE trileaflet conduits) that rely on the surgeon's experience for suturing, are time-consuming to prepare (30~40 minutes), have a low pass rate (only 78%), and suffer from suture tearing, suture gap reflux, and thrombosis (occurrence rate of about 8%). At the same time, it avoids the structural weaknesses of traditional valve sinus splicing design and improves overall durability.

[0036] (2) The present invention has a metal stent structure inside the tube, which can stabilize hemodynamics, prevent tube collapse, and meet the requirements for valve delivery via intravascular implantation.

[0037] (3) The integrated valved conduit of the present invention can be customized and has stronger adaptability: combined with the customized valve leaflet mold, the valve leaflet shape, conduit inner diameter, number of valve leaflets and valve sinus size can be adjusted according to the patient's hemodynamic parameters and anatomical size, breaking through the adaptability limitations of traditional standardized products.

[0038] (4) The materials and processes used in this invention are controllable and have high clinical applicability: the biocompatible polymer materials used are widely available and the preparation process is simple and controllable, which can reduce the risk of material degradation and calcification; the sutureless process does not rely on the experience of senior surgeons, which is convenient for promotion in primary hospitals and helps to alleviate the regional imbalance of right ventricular outflow tract reconstruction surgery and reduce medical costs.

[0039] (5) The integrated valved conduit of this application is applicable to the replacement of peripheral venous valves and pulmonary artery valves, and can realize surgical and intravascular implantation of areas with human valve structures. Attached Figure Description

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0041] Figure 1 This is a schematic diagram of the structure of the metal receiver in an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the structure of the leaflet mold in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the structure of the leaflet mold fitted into the metal receiver in an embodiment of the present invention;

[0044] Figure 4 This is a three-dimensional structural diagram of the integrated two-lobed pipe with flaps in Embodiment 1 of the present invention;

[0045] Figure 5 This is a top view schematic diagram of the integrated two-lobed valve pipe in Embodiment 1 of the present invention;

[0046] Figure 6 This is a three-dimensional structural diagram of the integrated three-lobed pipe with valves in Embodiment 2 of the present invention;

[0047] Figure 7 This is a top view schematic diagram of the integrated three-lobed pipe with flaps in Embodiment 2 of the present invention;

[0048] Figure 8 This is a three-dimensional structural diagram of the integrated two-lobed pipe with flaps in Embodiment 3 of the present invention;

[0049] Figure 9 This is a top view schematic diagram of the integrated two-leaf lobed pipe in Embodiment 3 of the present invention.

[0050] Illustration:

[0051] 1-Metal receiver; 2-Valve mold; 21-Tubular body; 22-Archive protrusion; 3-Integral valved tube; 31-Tube; 32-Valve; 33-Base; 34-Free surface; 35-Metal support. Detailed Implementation

[0052] The embodiments of the technical solution of the present invention will be described in detail below with reference to the examples. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and are therefore only examples, and should not be used to limit the scope of protection of the present invention.

[0053] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0054] This invention provides an integrated valve-type conduit 3, such as... Figures 1-9 As shown, the integrated valved conduit 3 includes a leaflet 32 ​​and a conduit 31;

[0055] The leaflet 32 ​​and the pipe 31 are formed into one piece by sintering, without the need for stitching and fixing; the leaflet 32 ​​is two or three leaflets, and the leaflet 32 ​​includes a base 33 and a free surface 34. The junction between two adjacent free surfaces 34 and the base 33 are integrally connected to the pipe 31.

[0056] The integrated valved conduit 3 of this invention forms the valve leaflet 32 ​​and conduit 31 into one piece through high-temperature sintering, eliminating the need for suture fixation. This solves the problems of complex preparation process, long preparation time, poor product consistency, and early tearing, regurgitation, and thrombosis risks caused by manual suturing of the valve leaflet 32 ​​and conduit 31 in the prior art, as well as the stress concentration at the suture site. At the same time, by setting the structure of the valve leaflet mold 2 and combining it with the morphology of the valve leaflet 32, it can be customized according to the patient's hemodynamic characteristics, thereby improving hemodynamic performance.

[0057] In this invention, the specific shape of the leaflet 32 ​​is not uniquely limited and can be adjusted using a mold according to the patient's hemodynamic characteristics. Typically, when the free surface of the leaflet mold 2 is fully unfolded, it is a semi-ellipse with its minor axis halved. This semi-ellipse is defined by its major axis (a) and minor axis (b), and the focal length (c, the distance from the center to a focal point) satisfies (c...). 2 =a 2 -b 2 The eccentricity (e=c / a) determines the flatness of the ellipse (when e=0 it is a circle, the closer e is to 1 the flatter it is), and different anatomical needs can be adapted by adjusting the major axis and minor axis parameters; at the same time, the valve sinus structure is formed synchronously with the formation of the conduit 31, and its outward convexity and size can be preset by the mold to ensure that it is adapted to the opening and closing movement of the leaflet 32 ​​and reduce blood flow turbulence.

[0058] In one embodiment, the conduit 31 includes a metal support 35, which provides support and enables interventional delivery.

[0059] In this invention, the connection between the leaflet 32 ​​and the pipe 31 is achieved through sintering to achieve a tight fit without gaps, which can effectively reduce the risk of backflow.

[0060] Another embodiment of the present invention provides a method for preparing an integral valved conduit 3, the method comprising the following steps:

[0061] (1) Dissolve the polymer in an organic solvent to obtain a polymer solution;

[0062] (2) A first thin film is formed on the surface of the cylindrical metal receiver 1, and one end is cut as a free edge;

[0063] (3) Fit one end of the leaflet mold 2 onto the free edge end of the first film, and then form a second film on the surface of the leaflet mold 2 and the surface of the first film with a polymer solution;

[0064] (4) The metal receiver 1 covered with the first and second thin films is sintered, and then the leaflet mold 2 and the metal receiver 1 are removed to obtain the integrated valve tube 3. The first and second thin films are completely fused by utilizing the difference in melting points of different polymers (at least one polymer melting point is within the sintering temperature range). During the sintering process, the leaflet mold 2 avoids the accidental fusion of the first thin film (leaflet) and the second thin film. The base 33 of the leaflet 32 ​​and the junction of the adjacent free surface 34 are sintered with the second thin film by external extrusion. The valve sinus structure is shaped by the fusion of each layer of material. Finally, the excess material is removed by laser cutting, and the leaflet mold 2 is removed to obtain the integrated valve tube 3.

[0065] The above-mentioned preparation method of the present invention achieves the integrated molding of leaflet 32 ​​and conduit 31 by high-temperature sintering, without the need for suture fixation. This solves the problem that the preparation process of leaflet 32 ​​and conduit 31 by suture fixation in the prior art is complicated and time-consuming, and causes early tearing of the suture site after implantation due to interface stress concentration.

[0066] In one embodiment, step (3) is followed by: fitting the metal support 35 onto the surface of the second film layer, and continuing to form a third film layer on the surface of the metal support 35.

[0067] In one embodiment, in step (1), the polymer is selected from at least one of polyurethane, polycaprolactone, polystyrene, polytetrafluoroethylene, and polyethylene glycol. Specifically, a single polymer or a blend of multiple polymers can be selected according to the mechanical properties (such as flexibility and support) and biocompatibility requirements of the valved conduit. For example, a blend of polyurethane and polycaprolactone can take into account the differences in elasticity and sintering melting point.

[0068] The polymer in this invention is a high molecular material with a wide range of raw material sources, and the preparation process is simple and reduces the risk of degradation and calcification. The integrated valved conduit 3 of this invention is suitable for surgical implantation and minimally invasive intravascular delivery, and is adapted to the replacement needs of pulmonary valves and venous valves in the human body, avoiding the defects of traditional manual suturing.

[0069] In one embodiment, in step (3), the leaflet mold 2 includes a tubular body 21 and arc-shaped protrusions 22 disposed at one end of the tubular body 21 and spaced apart.

[0070] In one embodiment, the arc-shaped protrusion 22 of the leaflet mold 2 is fitted onto the free edge end of the first thin film, and the connection between the arc-shaped protrusion 22 and the tubular body 21 is aligned with the free edge.

[0071] In one embodiment, in step (3), the inner diameter of the leaflet mold 2 can be any value between 8 and 30 mm, and can be selected according to clinical needs.

[0072] In one embodiment, in step (3), there is at least one arc-shaped protrusion 22. When the leaflet 32 ​​has two leaves, there are two arc-shaped protrusions 22. When the leaflet 32 ​​has three leaves, there are three arc-shaped protrusions 22.

[0073] In one embodiment, in steps (2) and (3), the formation methods of the first thin film (leaf layer), the second thin film (inner duct layer) and the third thin film (outer duct layer) are selected from any one of electrospinning, 3D printing, spin coating, dip coating, spraying and casting, respectively; wherein when electrospinning is used, the film thickness in the convex region of the valve sinus can be made uniform by adjusting the spinning voltage, flow rate and receiving distance, so as to avoid local excessive thinness leading to insufficient structural strength.

[0074] Preferably, in step (4), the sintering temperature can be adjusted according to the melting point of the selected polymer. Specifically, the sintering temperature is 50~150℃ and the holding time is 0.01~2h to ensure that the materials of each layer are tightly fused and the structural integrity of the metal support 35, leaflet 32 ​​and pipe 31 is not damaged. During the cutting process, high-precision laser cutting is used for the edge of the valve sinus to avoid affecting the opening and closing sealing of the leaflet due to cutting errors.

[0075] In one embodiment, the leaflet mold 2 can prevent the leaflet 32 ​​from fusing with the pipe 31 during the sintering process. The junction of the base 33 of the leaflet 32 ​​and the adjacent free surface 34 is sintered together with the second film by external extrusion.

[0076] In one embodiment, the cutting method is laser cutting to ensure the accuracy of the free surface 34 of the leaflet 32 ​​and the port of the pipe 31.

[0077] In this invention, the thickness of the first, second, and third thin films in the above preparation method is not specifically limited. Those skilled in the art can make conventional selections according to actual needs. Preferably, the thickness of the first thin film is 30~200µm, and the thicknesses of the second and third thin films are 30~200µm, respectively.

[0078] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0079] Example 1

[0080] This embodiment describes an integrated valved conduit 3 (bilobed) suitable for pulmonary artery reconstruction in children. Figure 1-5 As shown, the integrated valved conduit 3 (two-leaf) includes a leaflet 32 ​​and a conduit 31. The total length of the conduit 31 is 45 mm, which is adapted to the anatomical dimensions of the pulmonary artery.

[0081] The inner diameter of the conduit 31 is customized to 18mm, which is consistent with the average inner diameter range of the pulmonary artery in children of this age group. There are two leaflets 32, symmetrically distributed inside the conduit 31. The base 33 of the leaflets 32 is completely fitted to the inner layer of the conduit 31, and the junction of adjacent free surfaces 34 is tightly connected to the conduit 31 through sintering, without any suture gaps. The arc-shaped protrusion 22 of the leaflet mold 2 is semi-elliptical when laid flat, with a major axis a = 22mm and a minor axis b = 10mm. The focal length c is calculated based on the ellipse parameters. = = = With a diameter of approximately 19.6 mm and an eccentricity of e=c / a≈19.6 / 22≈0.89, this flat design can adapt to the physiological characteristics of children's pulmonary artery blood flow velocity being relatively slow (approximately 0.8-1.2 m / s), reducing blood flow resistance.

[0082] The preparation method of the above-mentioned integrated valved conduit 3 includes the following steps:

[0083] (1) Polymer solution preparation: Polyurethane and polycaprolactone were dissolved in hexafluoroisopropanol at a mass ratio of 2:1 and stirred for 24 hours until completely dissolved to obtain a polymer solution with a concentration of 9%, wherein the melting point of polyurethane is about 170℃ and the melting point of polycaprolactone is about 60℃, which meets the requirements of subsequent sintering temperature.

[0084] (2) Preparation of the first film layer: The polymer solution was electrospinned to form the first film layer on the surface of the metal receiver 1. The electrospinning parameters were set as follows: 23G spinneret, voltage 16kV, spinning speed 2.0mL / h, receiving distance 15cm, ambient humidity 35%, temperature 20℃, spinning time 1.5h, and finally a uniform first film layer with a thickness of 100µm was formed. After spinning, one end of the first film layer was cut with a laser cutting device to shape the free edge contour of the leaflet.

[0085] (3) Preparation of the second film: The customized bilobal leaf mold 2 is placed on the surface of the first film, ensuring that the connection between the arc-shaped protrusion 22 and the tubular body 21 is aligned with the free edge to avoid subsequent leaf displacement. Electrospinning is used again to form the second film on the leaf mold 2 and the surface of the first film with the same spinning parameters. The spinning time is 1 hour and the thickness is 200µm. At this time, the first film, leaf mold 2 and second film are tightly attached.

[0086] (4) High-temperature sintering and molding: The metal receiver 1 covered with the first and second thin films is sintered. The sintering temperature is set to 80℃ (within the melting point range of polycaprolactone, lower than the melting point of polyurethane, which allows polycaprolactone to melt and achieve interlayer fusion while retaining the structural support of polyurethane), and the holding time is 0.2h. During the sintering process, the arc-shaped protrusions 22 on the leaf mold 2 isolate the overlapping part of the first and second thin films to prevent accidental fusion and the formation of free surface 34. The area of ​​the first thin film other than the free surface 34 is sintered with the second thin film by external extrusion to achieve tight fusion of polymer fibers. After sintering, it is cooled to room temperature, and the excess material at both ends of the second thin film is removed by laser cutting equipment. Finally, the leaf mold 2 is taken out to obtain an integrated petal-shaped pipe 3 (two-leaf).

[0087] Example 2

[0088] This embodiment describes an integrated valved conduit 3 (trilobite) suitable for adult pulmonary artery repair, such as... Figures 1-3 , Figures 6-7 As shown, the integrated valved conduit 3 (trilobite) includes a leaflet 32 ​​and a conduit 31. The total length of the conduit 31 is 40 mm, which is adapted to the anatomical requirements of the pulmonary artery.

[0089] The inner diameter of the conduit 31 is customized to 25mm, which conforms to the average inner diameter range of the adult pulmonary artery. There are three free surfaces 34, symmetrically distributed at 120° on the inner side of the conduit 31. The base 33 of the leaflet 32 ​​fits seamlessly with the conduit 31, and the junctions of adjacent free surfaces 34 are firmly connected to the conduit 31 through sintering. The arc-shaped protrusion 22 of the leaflet mold 2 is semi-elliptical when laid flat, with a major axis a=28mm and a minor axis b=14mm. The calculated focal length c≈24.2mm and eccentricity e≈0.86 are designed to adapt to the blood flow velocity of the adult pulmonary artery (approximately 1.0-1.5m / s), balancing blood flow permeability and regurgitation control.

[0090] The preparation method of the above-mentioned integrated valved conduit 3 includes the following steps:

[0091] (1) Preparation of polymer solution: Polyurethane and polycaprolactone were dissolved in hexafluoroisopropanol solvent at a mass ratio of 2:1 and stirred for 6 hours until the solution was uniformly dissolved to obtain a polymer solution with a concentration of 9%.

[0092] (2) Preparation of the first film layer: A cylindrical metal receiver 1 with a diameter of 17 mm was selected and covered with aluminum foil to achieve conductivity. The first film layer was prepared by electrospinning. The electrospinning parameters were adjusted as follows: 21G spinneret, voltage 18kV, spinning speed 2.5mL / h, receiving distance 16cm, ambient humidity 30%, temperature 22℃, spinning time 2h, forming a first film layer with a thickness of 110µm. After spinning, the film was initially cut with laser cutting according to the outline of the three-lobed semi-elliptical free surface to shape the outline of the free edge of the lobes.

[0093] (3) Preparation of the second film: The customized trilobal leaflet mold 2 is placed on the surface of the first film, ensuring that the connection between the arc-shaped protrusion 22 and the tubular body 21 is aligned with the free edge to avoid subsequent leaflet displacement. Electrospinning is used again to form the second film on the leaflet mold 2 and the surface of the first film with the same spinning parameters. The spinning time is 1 hour and the thickness is 200µm. At this time, the first film, leaflet mold 2 and second film are tightly attached.

[0094] (4) High-temperature sintering and molding: The metal receiver 1 covered with the first and second thin films is sintered at a temperature of 90°C (to meet the fusion requirements of the polymer compound system) and held for 0.2 hours. During the sintering process, the arc-shaped protrusions 22 on the leaf mold 2 isolate the overlapping part of the first and second thin films to prevent accidental fusion and form a free surface 34. The area of ​​the first thin film other than the free surface 34 is sintered with the second thin film by external extrusion to achieve close fusion of polymer fibers. After cooling, the second thin film of the pipe is laser-cut to the preset length, the leaf mold 2 is removed, and an integrated pipe 3 (three-leaf) with a leaf is obtained.

[0095] Example 3

[0096] This embodiment describes an integrated valved conduit 3 (bileaflet) suitable for minimally invasive interventional valve repair in humans, such as... Figures 1-3 , Figures 8-9 As shown, the integrated valved conduit 3 includes a leaflet 32 ​​and a conduit 31. The total length of the conduit 31 is 30 mm, which is adapted to the anatomical path and length requirements of interventional delivery and can be used to improve the problem of blood reflux caused by valvular insufficiency.

[0097] The inner diameter of the conduit 31 is customized to 18mm; there are two free surfaces 34, symmetrically distributed on the inner side of the conduit 31. The base 33 of the leaflet 32 ​​is completely fitted with the inner layer of the conduit 31. The junction of adjacent free surfaces 34 is tightly connected to the inner layer of the conduit 31 through sintering, without any seam gaps. When the arc-shaped protrusion 22 of the leaflet mold 2 is laid flat, it is semi-elliptical, with a major axis a=22mm and a minor axis b=10mm. According to the ellipse parameters, the focal length c≈19.6mm and the eccentricity e≈0.89 are calculated. This flat design can adapt to the physiological characteristics of children's pulmonary artery blood flow velocity being relatively slow (about 0.8-1.2m / s), reducing blood flow resistance.

[0098] The preparation method of the above-mentioned integrated valved conduit 3 includes the following steps:

[0099] (1) Polymer solution preparation: Polyurethane and polycaprolactone were dissolved in hexafluoroisopropanol at a mass ratio of 2:1 and stirred for 18 hours until completely dissolved to obtain a polymer solution with a concentration of 9%. The melting point of polyurethane is about 170°C and that of polycaprolactone is about 65°C. The difference in melting points between the two can meet the requirements of interlayer fusion during subsequent sintering. Moreover, this compound system has both flexibility and biocompatibility, which is suitable for the slight deformation of the tubes during lower limb activities.

[0100] (2) Preparation of the first thin film: A cylindrical metal receiver 1 with a diameter of 17 mm was selected and its surface was covered with aluminum foil to achieve conductivity. The first thin film was formed on the surface of the metal receiver 1 by electrospinning. The electrospinning parameters were set as follows: 25G spinneret, voltage 15kV, spinning speed 1.8mL / h, receiving distance 14cm, ambient humidity 40%, temperature 21℃, spinning time 1.2h, and finally a uniform first thin film with a thickness of 90µm was formed. After spinning, the first thin film was cut at one end by laser cutting equipment according to the preset 2-lobed semi-elliptical free surface contour to shape the lobe free edge contour.

[0101] (3) Preparation of the inner and outer layers of the conduit (second and third film layers): The customized two-leaf valve mold 2 is placed on the surface of the first film layer. The connection between the arc-shaped protrusion 22 and the tubular body 21 is aligned with the free edge to prevent subsequent valve displacement from affecting the opening and closing function. The second film layer is formed on the surface of the valve mold 2 and the first film layer using electrospinning with the same spinning parameters. The spinning time is 0.9h and the thickness is 90µm. Then, the metal support 35 (material memory alloy, diameter 12mm, length 48mm) is placed on the surface of the second film layer. The spinning is continued for 1h with the same parameters to form a third film layer with a thickness of 95µm. At this time, the first film layer, valve mold 2, inner and outer layers of the conduit (second and third film layers) are tightly attached to the metal support 35. The metal support 35 is wrapped between the second and third film layers, which can provide stable support and does not directly contact the blood.

[0102] (4) High-temperature sintering and molding: The metal receiver 1 covered with the first film, the second film and the third film is sintered. The sintering temperature is set to 75℃ (within the melting point range of polycaprolactone, lower than the melting point of polyurethane, which can melt polycaprolactone to achieve tight fusion between the first film and the inner layer of the pipe, and between the inner layer of the pipe and the outer layer of the pipe, while retaining the structural stability of polyurethane and the shape memory characteristics of the metal support 35), and the holding time is 0.3h. During the sintering process, the arc-shaped protrusion 22 on the leaf mold 2 isolates the overlapping part of the first film and the second film to prevent accidental fusion and the formation of free surface 34. The area of ​​the first film other than the free surface 34 is sintered with the second film by external extrusion to achieve tight bonding of polymer fibers. After sintering, it is cooled to room temperature, and the two ends of the pipe are cut to a preset length of 50mm using a laser cutting device to remove excess material. Finally, the leaf mold 2 is taken out to obtain an integrated valve pipe 3 (two-leaf intervention type).

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for preparing an integrated valved conduit, characterized in that, The preparation method includes the following steps: (1) Dissolve the polymer in an organic solvent to obtain a polymer solution; (2) A first thin film is formed on the surface of a cylindrical metal receiver, and one end is cut as a free edge; (3) Fit one end of the leaflet mold onto the free edge end of the first film, and then form a second film on the surface of the leaflet mold and the surface of the first film with a polymer solution; (4) The metal receiver covered with the first and second thin films is sintered, and then the leaflet mold and the metal receiver are removed to obtain the integrated valved pipe. In step (3), the leaflet mold includes a tubular body and an arc-shaped protrusion disposed at one end of the tubular body and spaced apart; the arc-shaped protrusion of the leaflet mold is fitted onto the free edge end of the first film, and the connection between the arc-shaped protrusion and the tubular body is aligned with the free edge.

2. The preparation method according to claim 1, characterized in that, Step (3) is followed by: fitting a metal support onto the surface of the second film layer, and continuing to form a third film layer on the surface of the metal support.

3. The preparation method according to claim 1, characterized in that, In step (1), the polymer is selected from at least one of polyurethane, polycaprolactone, polystyrene, polytetrafluoroethylene and polyethylene glycol.

4. The preparation method according to claim 1, characterized in that, In step (3), the inner diameter of the leaf mold is 8~30mm.

5. The preparation method according to claim 1, characterized in that, In step (3), there is at least one arc-shaped protrusion.

6. The integral valved conduit prepared by the method according to any one of claims 1 to 5, characterized in that, The integrated valved conduit consists of valve leaflets and a conduit. The petals and the pipe are formed as one piece by sintering, without the need for stitching; the petals are two or three petals, and each petal includes a base and a free surface, with the junction between two adjacent free surfaces and the base being integrally connected to the pipe.

7. The integrated valve-type conduit according to claim 6, characterized in that, The pipeline includes a metal support.

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