Patent Publication Number: US-2023139430-A1

Title: Occluder and Occlusion System

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation application of PCT Application No. PCT/CN2021/103311, filed on Jun. 29, 2021, which claims the priority of Chinese Patent Application No. 202010625562.0, filed on Jul. 1, 2020, and Chinese Patent Application No. 202021260172.X, filed on Jul. 1, 2020, the entire contents of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present application relates to the field of medical devices, in particular to an occluder for occluding human body defects, and an occlusion system provided with the occluder. The occluder can occlude an oval foramen, and can also be used to occlude patent ductus arteriosus, and atrial septal and ventricular septal defects. 
     DESCRIPTION OF THE PRIOR ART 
     Oval foramen is usually closed in the first year after birth. If the oval foramen is not closed in children over 3 years, it is called Patent Oval Foramen (PFO). The oval foramens in 20% — 25% of the adults are not closed completely. Patent oval foramen (PFO) is a malformation in which the primary and secondary diaphragms at the oval fossa are not completely fused, with a permanent fissure-like defect therebtween, resulting in horizontal atrial shunt. Patent oval foramen is associated with a variety of clinical conditions, including paradoxical systemic embolism, such as ischemic stroke, transient ischemic attack, myocardial infarction, peripheral vascular embolism, decompression sickness, hypoxemia and aura migraine and so on. 
     In recent year, because of the advancement of cardiac catheterization technology and the improvement of occluder material, interventional occlusion has become the first clinical choice instead of thoracotomy for patent oval foramen with indication. In the prior art, the patent oval foramen occluder generally includes two disks and a cylindrical slender waist connected between the two disks. The cylindrical slender waist presses the primary septum and the secondary septum to be deformed, and the two disks clamp and fix the deformed defect to block blood flow. 
     However, the length of the cylindrical slender waist of the occluder for the patent oval foramen in the prior art cannot be adjusted. Therefore, the exiting occluder is only suitable for treatment of the patent oval foramen with the overlapping length of the primary septum and the secondary septum within a certain range. In the case of a patent oval foramen with a longer or shorter overlapping length, the occlusion effect is not ideal, a large residual shunt can be easily generated between the primary diaphragm and the secondary diaphragm after treatment, and the blood flow rate would be changed when the blood flows through the oval foramen, with a risk of thrombosis. For this reason, patients need to prolong the time of anticoagulant therapy, and if the resulted thrombus enters the blood circulation, it can cause serious adverse events such as embolism. 
     SUMMARY OF THE DISCLOSURE 
     The present application provides an occluder for occluding a defect in a vasculature, the occluder comprising: 
     a first occluding disk and a second occluding disk for respectively covering different openings of the defect, wherein the first occluding disk is provided with a connecting member, and the connecting member is provided with a threading hole, and a tightening wire passing through the threading hole of the connecting member, two ends of the tightening wire passing through the second occluding disk and forming an adjusting knot on a side of the second occluding disk facing away from the first occluding disk, and a spacing between the first occluding disk and the second occluding disk being adjustable by the ends of the tightening wire. 
     The present application further provides an occlusion system comprising an occluder comprising a first occluding disk, a second occluding disk and a tightening wire. The first occluding disk and the second occluding disk are respectively used to cover different openings of a defect. The first occluding disk is provided with a connecting member, and the connecting member is provided with a threading hole. The tightening wire passes through the threading hole of the connecting member, two ends of the tightening wire pass through the second occluding disk and form an adjusting knot on a side of the second occluding disk facing away from the first occluding disk, and a spacing between the first occluding disk and the second occluding disk is adjustable by the ends of the tightening wire. The delivery device is used to connect the tightening wire and for controlling the ends of the tightening wire to adjust the spacing between the first and second occluding disks. 
     In the occlusion system provided by the present application, two occluding disks are used to respectively cover different openings of the defect, two ends of the tightening wire pass through the second occluding disk and form an adjusting knot at a side of the second occluding disk facing away from the first occluding disk, wherein the distance between the first occluding disk and the second occluding disk can be adjusted by the ends of the tightening wire, in order to occlude different types of defects, which is beneficial to improving the closeness between the two occluding disks and the peripheral tissues of the defect, thereby stably occluding the defect. That is, after the occluder is implanted, the defect is less deformed, without affecting the endothelialization on the occluding disk, reducing the generation of residual shunt, avoiding the requirements for customized occluders due to specific defects of individual patients, expanding the applications of the occluder so that more patients can benefit from the minimally invasive surgery. 
     In addition, the tightening wire passes through the threading hole of the connecting member to connect the first occluding disk, so that the tightening wire can freely slide through the threading hole in the process of adjusting the tightening wire to change the length of the tightening wire between the two occluding disks, thereby changing the distance between the two occluding disks. In contrast to the case where the tightening wire is directly connected to the first occluding disk without passing through the threading hole of the connecting member, the connection position of the tightening wire with the first occluding disk cannot be easily changed, and in the process of adjusting the distance between the two occluding disks, the tightening wire can slide smoothly through the threading hole. In addition, in the case where the first occluding disk is covered with a film such as a flow-blocking film, as the tightening wire passes through the threading hole of the connecting member to connect the first occluding disk, eyelets in the film on the first occluding disk for connecting the tightening wire can be avoided, maintaining the wholeness of the film, and reducing the generation of residual shunt and film breakage after the occluder is implanted into the human body. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings for the embodiment are briefly described below. It is apparent that the drawings in the following description are some embodiments of the present application, for those skilled in the art, other drawings can be obtained from the drawings without creative labor. 
         FIG.  1    is a schematic structural view of an occlusion system according to an embodiment of the present application. 
         FIG.  2    is a schematic structural view of a first occluding disk of the occlusion system of  FIG.  1   . 
         FIG.  3    is an enlarged view of part III of  FIG.  2   . 
         FIG.  4    is an enlarged view of part IV of  FIG.  1   . 
         FIG.  5    is a schematic structural view of part of the first support frame and one of the second coils shown in  FIG.  2   . 
         FIG.  6    is a schematic structural view showing the knotting manner of each second coil shown in  FIG.  2   . 
         FIG.  7    is an enlarged view of the adjusting knot shown in  FIG.  1   . 
         FIG.  8    is a schematic structural view of another embodiment of the first occluding disk shown in  FIG.  2   . 
         FIG.  9    is a schematic structural view of a further embodiment of the first occluding disk shown in  FIG.  2   . 
         FIG.  10    is a schematic structural view of a still further embodiment of the first occluding disk shown in  FIG.  2   . 
         FIG.  11    is a schematic structural view of another embodiment of the first support frame and one of the second coils shown in  FIG.  5   . 
         FIG.  12    is a schematic structural view of a further embodiment of the first support frame and one of the second coils shown in  FIG.  5   . 
         FIG.  13    is a schematic structural view of a structure of the support frame of the occluder according to one embodiment of the present application. 
         FIG.  14    is a schematic structural view of another structure of the support frame of the occluder according to one embodiment of the present application. 
         FIG.  15    is a schematic structural view of the support frame of  FIG.  14    with a flow-blocking film provided thereon. 
         FIG.  16    is a schematic structural view of another structure of the support frame of the occluder according to one embodiment of the present application. 
         FIG.  17    is a schematic structural view of another structure of the support frame of the occluder according to one embodiment of the present application. 
         FIG.  18    is a schematic structural view of another structure of the support frame of the occluder according to one embodiment of the present application. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The technical solutions according to the embodiments of the present application will be clearly and fully described below with reference to the drawings according to the embodiments of the present application. Apparently, the described embodiments are only part of the embodiments of the present application, but not all embodiments. Based on the embodiments of the present application, other embodiments obtained by the skilled person in the art without any creative labor fall within the protection scope of the present application. 
     In the description of the present application, the “proximal end” refers to the end close to the control from the operator and the “distal end” refers to the end away from the control from the operator. The axial direction refers to the direction along the central axis of the occluder, and the radial direction is the direction perpendicular to the central axis. These terms are only for convenience of description and should not be construed as limitations on the present application. 
     Referring to  FIGS.  1  to  3   , an occlusion system  100  is provided, which includes an occluder  20  for occluding a defect in a vasculature and a delivery device  50  for releasing the occluder  20 . The defect includes, but not limited to, an oval foramen, a ductus arteriosus, an atrial septal defect, a ventricular septal defect, or the like. In the present application, the oval foramen is taken as an example of the defect for illustrating the advantages of the occlusion system  100  for treating a patent oval foramen. It can be understood that the defect can be other defects mentioned above. 
     The occluder  20  includes a first occluding disk  21 , a second occluding disk  23 , and a tightening member. The first occluding disk  21  and the second occluding disk  23  are respectively used to cover different openings of the defect in the vasculature. The first occluding disk  21  is provided with a connecting member  27  which has a threading hole  270 . The tightening member is a tightening wire  25 , which passes through the threading hole  270  of the connecting member  27 . Two ends of the tightening wire  25  pass through the second occluding disk  23  and form an adjusting knot  250  on the side of the second occluding disk  23  facing away from the first occluding disk  21 . The spacing between the first occluding disk  21  and the second occluding disk  23  can be adjusted through the ends of the tightening wire  25 . The delivery device  50  includes a sheath  52  for receiving the occluder  20  and delivering the occluder  20  into the vasculature of the human body and a handle  54  connected to the proximal end of the sheath  52  for the operator to control the delivery and release of the occluder  20 , and the distance between the first occluding disk  21  and the second occluding disk  23  can be adjusted by adjusting the tightening wire  25  in order to meet the requirements of different patients and different tissue anatomies. 
     After implantation of the occlusion system  100  of the present application, the first occluding disk  21  and the second occluding disk  23  respectively cover on two sides of the tissue, wherein the sides of the first occluding disk  21  and the second occluding disk  23  for clamping the tissue are the inner sides of the first occluding disk  21  and the second occluding disk  23 , and the sides of the first occluding disk  21  and the second occluding disk  23  facing away from the clamped tissue are the outer sides. In this embodiment, the occluder is an oval foramen occluder. The peripheries of the openings on the opposite sides of the oval foramen, i.e., the areas on the two sides of the primary diaphragm and the secondary diaphragm adjacent to the oval foramen are covered by the first occluding disk  21  and the second occluding disk  23 , respectively, wherein the sides of the first occluding disk  21  and the second occluding disk  23  covering the primary diaphragm and the secondary diaphragm are the inner sides, and the sides of the first occluding disk  21  and the second occluding disk  23  facing away from the primary diaphragm and the secondary diaphragm are the outer sides. The tightening wire  25  passes through the threading hole  270  of the connecting member  27 , and two ends of the tightening wire  25  pass through the second occluding disk  23  and form the adjusting knot  250  on the outer side of the second occluding disk  23 . The spacing between the first occluding disk  21  and the second occluding disk  23  can be controlled by adjusting the tightening wire  25  connected with the first occluding disk  21  and the second occluding disk  23 , in order to occlude different types of defects and to adapt to the anatomy of the patient, improving the closeness between the first and second occluding disks  21  and  23  and the tissues around the oval foramen, thereby stably occluding the oval foramen. As the distance between the first occluding disk  21  and the second occluding disk  23  is adjustable after implantation of the occluder  20 , the primary diaphragm and the secondary diaphragm are less deformed, without affecting the endothelialization of the primary diaphragm and the secondary diaphragm on the occluding disks, reducing the generation of residual shunt, avoiding the requirements for customized occluders due to specific oval foramens of individual patients, expanding the applications of the PFO occluder so that more patients can benefit from the minimally invasive surgery. Further, the tightening wire  25  passes through the threading hole  270  of the connecting member  27  to connect the first occluding disk  21  so that when adjusting the tightening wire  25 , the tightening wire  25  can slide freely through the threading hole  270  to change the length of the tightening wire  25  between the two occluding disks, thereby changing the distance between the two occluding disks. In contrast to the case where the tightening wire  25  is directly connected to the first occluding disk  21  without passing through the threading hole  270  of the connecting member  27 , the connection position of the tightening wire  25  with the first occluding disk  21  in the present application cannot be easily changed, and the tightening wire  25  can slide relatively smoothly through the threading hole  270  during the process of adjusting the distance between the two occluding disks. In addition, in the case where the first occluding disk  21  is covered with a film such as a flow-blocking film, as the tightening wire  25  passes through the threading hole of the connecting member  27  to connect the first occluding disk  21 , eyelets in the film on the first occluding disk  21  for connecting the tightening wire can be reduced, maintaining the wholeness of the film, and reducing the generation of residual shunt and film breakage after the occluder is implanted into the human body. 
     As shown in  FIG.  2    and  FIG.  3   , the first occluding disk  21  includes a central region  211  and an edge region  213  at the edge of the central region  211 . The connecting member  27  includes a first coil  271  disposed at the center of the central region  211 . The first coil  271  has an annular shape and is provided with the threading hole  270  through which the tightening wire  25  passes. When the tightening wire  25  is tensioned, the tightening wire  25  can slide through the first coil  271 , thereby adjusting the length of the tightening wire  25  between the first occluding disk  21  and second occluding disk  23 , and thus adjusting the distance between the two occluding disks. The first occluding disk  21  includes a first sleeve  214  and a first support frame  215  disposed within the central region thereof. Preferably, the first sleeve  214  is disposed at the geometric center of the first occluding disk  21 . The first support frame  215  includes a plurality of support rings. The plurality of support rings are connected to the first sleeve  214  and surround the first sleeve  214  so as to form the first support frame  215 . The first coil  217  is wound on the first sleeve  214 . It will be appreciated that in other embodiments, the first sleeve  214  can be disposed at an eccentric position on the first occluding disk  21 . 
     Preferably, the first coil  271  is disposed at the geometric center of the first occluding disk  21 , and the tightening wire  25  is tensioned after passing through the threading hole  270  of the first coil  271 . The first coil  271  and the tightening wire  25  are intersected at the geometric center of the first occluding disk  21 , so that the first occluding disk  21  can be uniformly pulled, and would not be easily tilted when adjusting the length of the tightening wire  25  after the first occluding disk  21  is positioned in place. 
     Preferably, the first sleeve  214  can be a steel sleeve with two open ends. Alternatively, the first sleeve  214  can be a combination of multiple steel sleeves. The first sleeve  214  has two opposite openings and a cavity  2140  between the openings. In one embodiment, the first coil  271  is a single coil, which passes through the two openings and the cavity  2140  and is hanged on the first sleeve  214 . In this embodiment, the cavity  2140  of the first sleeve  214  is a through hole extending along the thickness direction of the first occluding disk  21  (the direction perpendicular to the disk surface of the first occluding disk  21 ). The first coil  271  passes through the openings of the first sleeve  214  and the cavity  2140  and is connected to the peripheral wall of the first sleeve  214 . The first coil  271  is wound on the first sleeve  214  to form the threading hole  270  through which the tightening wire  25  movably passes. When the tightening wire  25  is pulled away from the first support frame  215 , the force bearing point of the first sleeve  214  is located on the geometric center line of the first support frame  215 . In this embodiment, the ends of the plurality of support rings are connected to the outer periphery of the first sleeve  214 , and are fixedly connected to the first sleeve  214  by welding or gluing. The first sleeve  214  is made of stainless steel, nickel-titanium alloy, or other biocompatible materials. 
     Specifically, the first coil  271  includes a threading coil  2712  and a positioning coil  2714  connected to each other. The threading coil  2712  has an annular shape and is provided with the threading hole  270 , and the positioning coil  2714  is wound on the first sleeve  214 . The threading coil  2712  and the positioning coil  2714  can be formed by the same suture or two sutures. In this embodiment, the first coil  271  is formed by knotting a suture at the knotting point  2715  to form the threading hole  270 , and the two ends of the suture are wound around the outer surface of the first sleeve  214  and fixedly connected by knotting at the knotting point  2716  to form the positioning coil  2714 . The positioning coil  2714  includes floating segments  2717  disposed on the first sleeve  214  and two positioning segments  2718  contacting the outer peripheral surface of the first sleeve  214 . The positioning coil  2714  includes at least two opposite floating segments  2717 , which are respectively located at two openings of the first sleeve  214 . The floating segment  2717  extends in the radial direction of the first sleeve  214  and passes through the geometric center of the first sleeve  214 . The connection between the threading coil  2712  and the positioning coil  2714  is located on at least one floating segment  2717  of the positioning coil  2714 , preferably at the midpoint of one floating segment  2717 . When the threading coil  2712  is tightened, the connection between the threading coil  2712  and the positioning coil  2714  and the threading coil  2712  are both located at the geometric center of the first sleeve  214 . In an alternative embodiment, the connection between the threading coil  2712  and the positioning coil  2714  and the threading coil  2712  are not necessarily to be located at the geometric center of the first sleeve  214 . 
     In other embodiments, the positioning coil  2714  is a coil formed by one suture that is wound around the outer surface of the first sleeve  214  and knotted fixedly, and the threading coil  2712  is a coil formed by another suture that is knotted and connected to the positioning coil  2714 . 
     As shown in  FIGS.  1  to  3   , the first occluding disk  21  and the second occluding disk  23  can have disk surfaces in a shape of a circle, a polygon, an ellipse, a triangle or other irregular shapes. The radial size of the first occluding disk  21  and the radial size of the second occluding disk  23  can be the same or different. For example, the radial size of the first occluding disk  21  can be smaller than the radial size of the second occluding disk  22 . In this embodiment, both the first occluding disk  21  and the second occluding disk  23  are substantially in the shape of a hexagonal disk, and the radial size of the first occluding disk  21  is equal to the radial size of the second occluding disk  23 . 
     The plurality of support rings of the first support frame  215  includes a first support ring  2151 . The first support ring  2151  includes a plurality of strands. The positioning coil  2714  passes through a gap between the plurality of strands of the first support ring  2151 , so that the positioning coil  2714  can be securely positioned on the first sleeve  214 . Preferably, the other end of the positioning coil  2714  further passes through a gap between the strands of another support ring on the opposite side, so that the positioning coil  2714  can be positioned on both sides by the strands of the respective support rings, thereby making the positioning of the positioning coil more stable. 
     In this embodiment, the first occluding disk  21  further includes a first flow-blocking film  218  disposed on the first support frame  215 . The first flow-blocking film  218  can be fixedly disposed on the inner surface and/or the out surface of the first support frame  215  by sewing, gluing or heat bonding. In the case where the first support frame  215  is in the form of a cage, the first flow-blocking film  218  can be fixedly disposed in the inner cavity of the first support frame  215 , and the first flow-blocking film  218  covers at least a portion of the inner surface or a portion of the outer surface of the first support frame  215 . In this embodiment, the first flow-blocking film  218  covers the surface of the first support frame  215  facing away from the second occluding disk  23 , that is, the first flow-blocking film  218  covers the outer surface of the first occluding disk  21 . The first sleeve  214  is disposed on the inner side of the first occluding disk  21 , and the first flow-blocking film  218  covers the opening of the first sleeve  214  facing the outer side of the first occluding disk  21  to seal the opening of the cavity  2140  of the first sleeve  214  facing the outer side of the first occluding disk  21 . In this embodiment, the positioning coil  2714  passes through the gap between the first flow-blocking film  218  and the first sleeve  214 , without passing through the first flow-blocking film  218 , maintaining the wholeness of the first flow-blocking film  218 , and reducing the generation of residual shunt and breakage of the first flow-blocking film  218  after implantation of the occluder  20 . 
     Optionally, the first sleeve  214  includes two layers of steel sleeves, the ends of the support rings are clamped in the gap between the two steel sleeves, in the cavity between the inner and outer steel sleeves. 
     In one embodiment, the positioning coil  2714  is glued to the first flow-blocking film  218  to prevent displacement of the positioning coil  2714 . In one embodiment, the first flow-blocking film  218  is disposed on the inner side of the first occluding disk  21 , the first sleeve  214  is disposed on the inner side or outer side of the first occluding disk  21 , and the positioning coil  2714  passes through the first flow-blocking film  218 , with a plurality of eyelets formed in the first flow-blocking film  218  for the positioning coil  2714  passing through. It can be understood that in other embodiments, the positioning coil  2714  and the flow-blocking film  218  can be connected through other connecting methods. Even in an alternative embodiment, the first flow-blocking film  218  can be removed. 
     As shown in  FIG.  1   , the structure of the second occluding disk  23  is similar to that of the first occluding disk  21 . The second occluding disk  23  also has a central region  231  and an edge region  233  around the central region  231 . The second occluding disk  23  includes a second sleeve  234  disposed at the central region thereof and a second support frame  235  connected around the second sleeve  234 . In this embodiment, the second sleeve  234  is fixedly disposed at the geometric center of the second occluding disk  23 , and a plurality of support rings of the second support frame  235  surround the second sleeve  234 . It will be appreciated that in other embodiments, the second sleeve  234  can be disposed eccentrically on the second occluding disk  23 . 
     As shown in  FIG.  4   , the structure of the second sleeve  234  is similar to that of the first sleeve  214 . The second sleeve  234  can be a steel sleeve with two open ends, or a combination of multiple steel sleeves. Specifically, the second sleeve  234  is cylindrical and has a cavity  2340 . Two ends of the tightening wire  25  pass through the second occluding disk  23  from the inner side to the outer side. Specifically, two ends of the tightening wire  25  pass through different positions of the second occluding disk  23 , respectively. Preferably, one end of the tightening wire  25  passes through the cavity  2340  of the second sleeve  234 , and the other end of the tightening wire  25  passes through the eyelet formed by the second support frame  235  around the second sleeve  234 . In an alternative embodiment, two ends of the tightening wire  25  pass through different eyelets formed by the second support frame  235 , respectively. In an alternative embodiment, the second sleeve  234  has two cavities extending along its axis, and two ends of the tightening wire  25  pass through different cavities of the second sleeve  234 . 
     The ends of the plurality of support rings are fixedly disposed on the outer peripheral surface or the inner peripheral surface of the second sleeve  234 . In this embodiment, the second sleeve  234  includes two layers of steel sleeves, and the ends of the support rings are clamped in the gap between the two steel sleeves. The cavity in the inner steel sleeve is used for the tightening wire passing therethrough. The second sleeve  234  is made of stainless steel, nickel-titanium alloy or other biocompatible materials. Preferably, regarding the second occluding disk  23 , the second sleeve  234  is disposed on the outer side of the second occluding disk  23 , i.e., the outer side of the second support frame  235 . The second flow-blocking film  238  is disposed on the inner side of the second occluding disk  23 , which facilitates tissue endothelialization. 
     In other embodiments, the ends of the support rings can be fixedly connected to the outer or inner peripheral surface of the second sleeve  234  by welding or gluing. 
     The second occluding disk  23  further includes a second flow-blocking film  238  disposed on the second support frame  235 . The second flow-blocking film  238  can be fixedly disposed on the inner surface and/or the outer surface of the second support frame  235 . In the case where the second support frame  235  is in the form of a cage, the second flow-blocking film  238  can be fixedly disposed in the inner cavity of the second support frame  235 , and the second flow-blocking film  238  covers at least a radial area of the second support frame  235 . In this embodiment, the second flow-blocking film  238  covers the surface of the second support frame  235  facing the first occluding disk  21 , that is, the second flow-blocking film  238  covers the inner side surface of the second support frame  235 . One end of the tightening wire  25  passes through the cavity  2340  of the second sleeve  234 , and the other end of the tightening wire  25  passes through the eyelet formed by the second support frame  235  and the area of the second flow-blocking film  238  corresponding to the eyelet. 
     The first flow-blocking film  218  and the second flow-blocking film  238  can use a non-biodegradable polymer film with good biocompatibility, such as ePTFE or PET materials. Alternatively, the first flow-blocking film  218  and the second flow-blocking film  238  can use an absorbable polymer film, such as polylactic acid, polycaprolactone, polylactic acid-polycaprolactone copolymers, etc. The first flow-blocking film  218  and the second flow-blocking film  238  can be fixed to the inner surface or the outer surface of the respective occluding disks by sewing or gluing, for occluding blood flow. 
     The first support frame  215  and the second support frame  235  each can be a braided mesh structure or a cut frame structure, so that the first occluding disk  21  and the second occluding disk  23  can closely contact the surfaces of the atrial septum. The first support frame  215  and the second support frame  235  can be any one of a single-layer braided mesh structure, a single-layer frame structure, a double-layered braided mesh structure or a double-layered frame structure, respectively. In the present application, the first support frame  215  and the second support frame  235  are each a single-layer braided mesh structure, and the plurality of the support rings are arranged around the sleeve by at least one round. In this embodiment, as the first sleeve  214  is disposed at the geometric center of the first occluding disk  21  and the second sleeve  234  is disposed at the geometric center of the second occluding disk  23 , the support rings of the first occluding disk  21  are arranged circumferentially around the geometric center of the first sleeve  214 , and the support rings of the second occluding disk  23  are arranged circumferentially around the geometric center of the second sleeve  234 . In a preferred embodiment, the support rings of the first occluding disk  21  and the second occluding disk  23  are evenly spaced. 
     As shown in  FIG.  2   , in this embodiment, the first support frame  215  includes six support rings which are arranged circumferentially around the geometric center of the first occluding disk  21 . Two adjacent support rings are cross-connected at a connection point  2155 . Specifically, the first support frame  215  further includes a second support ring  2152 , a third support ring  2153 , a fourth support ring, a fifth support ring, and a sixth support ring arranged in a clockwise direction from the first support ring  2151 . Each support ring is formed by bending a support rod. Two ends of each support ring located within the central region  211  are fixedly connected to the first sleeve  214 . The portion of each support ring located within the edge region  213  is located at the radial edge of the first occluding disk  21 . Taking the first support ring  2151  as an example, the first support ring  2151  is cross-connected with the second support ring  2152  and the sixth support ring, and the ends of the first support ring  2151  within the central region  211  are connected with the first sleeve  214  and connected with the end of the third support ring  2153  within the central region and the end of the fifth support ring within the central region, respectively. That is, the first support ring  2151 , the third support ring  2153  and the fifth support ring  2153  all have end connecting portions  2156 , and adjacent support rings are connected in one piece at the respective end connecting portion  2156 . For example, the first support ring  2151  and the third support ring  2153  are connected in one piece at the end connecting portion  2156 , the third support ring  2153  and the fifth support ring are connected in one piece at the end connecting portion  2156 , and the first support ring  2151  and the fifth support ring are connected in one piece at the end connecting portion  2156 . 
     As shown in  FIG.  2    and  FIG.  5   , the “cross-connection” between the first support ring  2151  and the second support ring  2152  refers to that at least one of two adjacent support rings includes a plurality of strands which are intertwined with each other or arranged parallel to each other, and the other support ring is inserted in the gap between the strands of the at least one support ring, such that two adjacent support rings are positioned relative to each other. For example, the first support ring  2151  includes a plurality of strands which are intertwined with each other or arranged parallel to each other, and the cross-connection between the second support ring  2152  and the first support ring  2151  is the gap between the strands of the first support ring  2151  where the second support ring  2152  is inserted into. The second support ring  2152  also includes a plurality of strands which are intertwined with each other or arranged parallel to each other, and the cross-connection of the second support ring  2152  and the third support ring  2153  is the gap between the strands of the second support ring  2152  where the third support ring  2153  is inserted into. 
     The intersections of the first support ring  2151  with the third support ring  2153  and the fifth support ring are at the end connecting portions  2156 , and the adjacent support rings are connected in one piece at the respective end connecting portion  2156 . The end connecting portions  2156  are located within the central region  211 , and the strands of two support rings are braided together at the end connecting portion  2156 . For example, the first support ring  2151  and the third support ring  2153  are braided together at the end connecting portion  2156  within the central region  211 , and the inter-braided region of the two support rings extend from the first sleeve  214  to the position where the two support rings are separated from each other. In an alternative embodiment, the strands of adjacent support rings at the end connecting portion  2156  are arranged parallel to each other, either secured in one piece by suture winding and knotting, or glued in one piece, or welded in one piece. 
     The connection points where the support rings of the first occluding disk  21  are cross-connected with each other are further away from the geometric center of the first occluding disk  21  than the connection points where the support rings of the first occluding disk  21  are braided together. 
     In an alternative embodiment, the connection points where the support rings of the first occluding disk  21  are cross-connected with each other are closer to the geometric center of the first occluding disk  21  than the connection points where the support rings of the first occluding disk  21  are braided together. 
     In an alternative embodiment, the support rings of the first occluding disk  21  are cross-connected with each other at all the connection points, or the support rings of the first occluding disk  21  are braided to each other at all the connection points. 
     In an alternative embodiment, the support rings of the first occluding disk  21  are cross-connected with each other at at least part of the connection points, or the support rings of the first occluding disk  21  are braided to each other at at least part of the connection points. 
     In the present embodiment, each support ring is formed by a plurality strands which are intertwined with each other or arranged parallel to each other, that is, the first support ring  2151  to the sixth support ring are each formed by a plurality strands. In an alternative embodiment, some of the support rings of the first occluding disk  21  each include a plurality of strands, and the other support rings of the first occluding disk  21  each include one strand. 
     The structure of the second support frame  235  is the same as that of the first support frame  215 . Therefore, the structure of the second support frame  235  would not be repeated herein. 
     The support rings of the first support frame  215  and the second support frame  235  can each be made of various biocompatible materials, i.e., each support ring can be made of various biocompatible materials. Various biocompatible materials include common materials used in the manufacture of releasable medical devices, such as memory alloy materials, preferably nickel-titanium alloy. Alternatively, the first support frame  215  and the second support frame  235  can be made of biodegradable materials, i.e., each support ring can be made of biodegradable materials. The biodegradable materials include, for example, polylactic acid (PLA), polycaprolactone (PCL), polyglycolide (PGA) or polyp-dioxocyclohexanone (PDO), etc. Alternatively, the first support frame  215  and the second support frame  235  can be made of high molecular polymer materials. 
     As shown in  FIG.  2   , the connecting member  27  further includes at least one second coil  273  disposed on the side of the first occluding disk  21  facing the second occluding disk  23  around the first coil  271 . The at least one second coil  273  has an annular shape and a threading hole  270 . The tightening wire  25  passes through the threading holes  270  of the first coil  271  and the second coil  273 . In this embodiment, the first occluding disk  21  is provided with a first coil  271  on the side thereof facing the second occluding disk  23  at the center and a plurality of second coils  273  surrounding the first coil  271 . The plurality of second coils  273  are evenly spaced around the first coil  271  by at least one round, so as to improve the uniformity of the force exerted on the first occluding disk  21  during the tension and release of the tightening wire  25 . In other an alternative embodiment, the second coils  273  are not necessarily to being evenly spaced. 
     Specifically, the first coil  271  is a central coil located at the geometric center of the first occluding disk  21 . The central coil refers to the coil of the first coil  271  and the second coils  273  that is closest to the geometric center of the first occluding disk  21 . The number of the plurality of second coils  273  is three. The three second coils  273  are arranged around the geometric center of the first sleeve  214  in an annular array, each of the second coils  273  is fixedly connected to the first support frame  215 , and the tightening wire  25  passes through the first coil  271  and each of the second coils  273 . 
     In an alternative embodiment, one of the second coils  273  is the central coil. 
     The second coil  273  is connected to the first support frame  215 . Specifically, the second coil  273  can be connected to the first support frame  215  by knotting. Alternatively, the second coil  273  can be clamped between the strands at the intersection of two adjacent support rings of the first support frame  215 , or can be glued to the first support frame  215 . 
     Preferably, the second coil  273  is disposed at the connection of two adjacent support rings, such as the connection point  2155  or the end connecting portion  2156  of the support rings. Specifically, in this embodiment, as shown in  FIG.  2   , the intersection of the end of the first support ring  2151  and the end of the third support ring  2153 , the intersection of the end of the first support ring  2151  and the end of the fifth support ring, and the intersection of the end of the third support ring  2153  and the end of the fifth support ring are each provided with a second coil  273 , so that the three second coils  273  are evenly spaced around the first sleeve  214 . 
     The second coil  273  is inserted in the gap in the intersection of the two support rings. As shown in  FIG.  5   , the second coil  273  is disposed at the intersection of the end of the first support ring  2151  and the end of the third support ring  2153 . Specifically, the second coil  273  penetrates the end connecting portion  2156  of the first support ring  2151  and the third support ring  2153 . At the end connecting portion  2156 , a plurality of strands of the first support ring  2151  and the third support ring  2153  are braided together. The second coil  273  passes through the gap between the strands of the end connecting portion  2156  so as to position the second coil  273  at the first support frame  215 . As shown in  FIG.  5   , in the present embodiment, the second coil  273  is connected to the end connecting portion  2156  of the two support rings at a portion of the end connecting portion  2156  away from the first sleeve  214 . In an alternative embodiment, the second coil  273  is connected to the end connecting portion  2156  of the two support rings at a portion of the end connecting portion  2156  close to the first sleeve  214  or at a middle portion of the end connecting portion  2156 . It will be appreciated that in an alternative embodiment, the second coil  273  can be disposed at the connection point  2155  where adjacent support rings are cross-connected, such as the connection point  2155  of the first support ring  2151  and the second support ring  2152  described above. 
     As shown in  FIG.  6   , the first coil  271  and the second coils  273  are each formed by a suture which is knotted several times in succession in the tying method as shown in  FIG.  6   , so that the knots of the first coil  271  and the second coils  273  are secure and thus the first coil  271  and the second coils  273  each can be stably maintained in a loop configuration, through which the tightening wire  25  can easily pass. The knot tying method shown in  FIG.  6    refers to that first looping the suture for forming the first coil  271  or the second coil  273  to form a connecting loop  2732 , and then passing one end of the suture through the connecting loop  2732  to form a fixed knot. 
     As shown in  FIG.  1    and  FIG.  7   , two ends of the tightening wire  25  are respectively configured as an adjusting section  251  and a locking section  253 . The adjusting section  251  or the locking section  253  includes a centering section  254  connected between the first coil  271  and the second occluding disk  23 . After passing through the second occluding disk  23 , the adjusting section  251  and the locking section  253  form an adjusting knot  250  on the side facing away from the first occluding disk  21  (the outer side of the second occluding disk  23 ). The end of the adjusting section  251  passes through the adjusting knot  250 , and the adjusting section  251  can be locked by locking the adjusting knot  250 , so as to fix the space between the first occluding disk  21  and the second occluding disk  23  through the tightening wire  25 . The centering section  254  is connected between the first occluding disk  21  and the second occluding disk  23 , preferably between the inner side of the first occluding disk  21  and the inner side of the second occluding disk  23 . The end of the centering section  254  away from the second occluding disk  23  passes through the threading hole  270  of the first coil  271  and the threading hole  270  of the second coil  273 . When the tightening wire  25  is tensioned, the first coil  271  is tightened by the centering section  254  so that the first occluding disk  21  can be forced at the center, which facilitates the positioning control of the first occluding disk  21 . 
     In an alternative embodiment, one of the second coils  273  is a central coil. 
     In an alternative embodiment, the adjusting section  251  and the locking section  253  each include a centering section  254 , and two centering sections  254  extend out of the same central coil. 
     In an alternative embodiment, both ends of the tightening wire  25  do not pass out from the central coil. 
     Specifically, as shown in  FIG.  7   , the locking section  253  includes a free end  2530 , and the adjusting section  251  includes a free end  2510 . The locking section  253 , the adjusting section  251  and the adjusting knot  250  are all disposed on the side of the second occluding disk  23  facing away from the first occluding disk  21 . The length of the centering section  254  can be adjusted by the adjusting section  251 . The free end  2530  of the locking section  253  and the free end  2510  of the adjusting section  251  are connected to the delivery device  50 . The free end  2510  can be pulled proximally by controlling the delivery device  50 , so that the tightening wire  25  can slide along the axial direction of the second occluding disk  23  (for example, through the cavity  2340  and the eyelets of the second support frame in this embodiment) and through the threading holes  270  of the first coil  271  and the second coil  273 , thereby shortening the length of the tightening wire between the first and second occluding disks  21 ,  23  and thus adjusting the waist length of the occluder  20 . The free end  2530  can be pulled proximally by controlling the delivery device  50 , so that the adjusting knot  250  can be locked so as to lock the adjusting section  251  by the adjusting knot  250 , thereby fixing the distance between the first occluding disk  21  and the second occluding disk  23  and thus fixing the distance between the first occluding disk  21  and the second occluding disk  23 , which is beneficial to maintain the relative position and contact between the primary, secondary diaphragms and the two occluding disks during and after the procedure, reducing the difficulty of withdrawing the delivery device  50 , facilitating the endothelialization of the two diaphragms on the occluder  20  to form a permanent atrial septum. 
     One end of the adjusting knot  250  is connected to a portion of the locking section  253  adjacent to the second occluding disk  23 , and the other end of the adjusting knot  250  is connected to the free end  2530  away from the second occluding disk  23 . When the adjusting knot  250  is not tightened, the free end  2510  can drive the adjusting section  251  connected thereto to slide through the adjusting knot  250 , so as to adjust the length of the centering section  254  between the first occluding disk  21  and the second occluding disk  23 . The free end  2530  of the locking section  253  is used to tighten the adjusting knot  250  so that the adjusting knot  250  can tighten a portion of the adjusting section  251  located therein, thereby fixing the length between the first occluding disk  21  and the second occluding disk  23 . 
     As shown in  FIG.  7   , the adjusting knot  250  includes a base loop  2501  and a locking loop  2503  connected to each other, and the base loop  2501  and the locking loop  2503  are formed by winding and knotting the locking section  253 . Specifically, one end of the base loop  2501  and one end of the locking loop  2503  are connected in one piece, and the other end of the base loop  2501  away from the locking loop  2503  (or the end of the base loop  2501  that is not connected with the locking loop  2503 ) extends to the second occluding disk  23 . The end of the locking loop  2503  away from the base loop  2501  (or the end of the locking loop  2503  that is not connected with the base loop  2501 ) is the free end  2530 . The free end  2510  of the adjusting section  251  passes through the base loop  2501  and the locking loop  2503 . When the base loop  2501  and the locking loop  2503  are not tightened, the free end  2510  can drive the adjusting section  251  to slide through the adjusting knot  250 , thereby adjusting the length of the centering section  254  between the first occluding disk  21  and the second occluding disk  23 . When the free end  2530  of the locking section  253  is pulled, the locking loop  2503  and the base loop  2501  are gradually tightened in turn, so that a portion of the adjusting section  251  can be tightened in the locking loop  2503 . 
     As shown in  FIG.  1   , in use, the first occluding disk  21  is delivered to the left atrium by the delivery device  50  and deployed there, and the second occluding disk  23  is delivered to the right atrium by the delivery device  50  and deployed there. The centering section  254  connected between the first occluding disk  21  and the second occluding disk  23  is flexible and adjustable in length. The centering section  254  passed through the oval foramen between the primary and secondary diaphragms. The free end  2510  of the adjusting section  251  can be pulled proximally to tension the centering section  254  which is located at the geometric center of the first occluding disk  21 , so that the centering section  254  is gradually shortened, that is, the distance between the first occluding disk  21  and the second occluding disk  23  is gradually reduced. Therefore, the primary diaphragm and the secondary diaphragm are closer to each other and clamped by the first occluding disk  21  and the second occluding disk  23 . The first occluding disk  21  covers the primary and secondary diaphragms around the oval foramen, and the second occluding disk  23  covers the primary and secondary diaphragms around the oval foramen. That is, the openings on the two sides of the oval foramen in the left and right atria are covered by the first occluding disk  21  and the second occluding disk  23 , respectively. Since the first and second occluding disks  21  and  23  each include a support frame and a flow-blocking film disposed on the support frame, the flow-blocking films on two sides of the oval foramen can prevent blood from flowing into the oval foramen, thereby preventing the blood from flowing from the left atrium into the right atrium, so as to achieve an instantaneous occlusion. After the occluder  20  is implanted, the primary and secondary diaphragms creep to the portions of the first and second occluding disks  21 ,  23  contacting the primary and secondary diaphragms, thereby closing the oval foramen after the endothelialization is completed and thus forming a complete atrial septum. In an alternative embodiment, the density of the support frames of the two occluding disks is sufficiently great so that the flow-blocking film can be removed, without affecting the endothelialization of the two diaphragms on the occluding disks, and avoiding a shunt in the oval foramen channel or with a small shunt in the oval foramen channel. 
     As shown in  FIG.  8   , the structure of the first occluding disk  21   a  according to another embodiment of the present application is similar to the structure of the first occluding disk  21  according to one of the above embodiments, and the difference therebetween is that: all the second coils  273  are removed from the first occluding disk  21 , that is, the connecting member of the first occluding disk  21   a  includes only the first coil  271 , and the tightening wire  25  passes through the threading hole  270  of the first coil  271 . When the tightening wire  25  is pulled proximally, the tightening wire  25  can slide through the first coil  271 , thereby adjusting the spacing between the two occluding disks. 
     As shown in  FIG.  9   , the structure of the first occluding disk  21   b  according to a further embodiment of the present application is similar to the structure of the first occluding disk  21  according to one of the above embodiments, and the difference therebetween is that: the connecting member of the first occluding disk  21   b  includes one first coil  271  and two second coils  273 , wherein the first coil  271  is disposed at the geometric center of the first occluding disk  21   b , and the two second coils  273  are disposed on the first occluding disk  21   b  and symmetrically arranged about the geometric center of the first occluding disk  21   b . In this embodiment, one second coil  273  is connected to the intersection of the end of the first support ring  2151  and the end of the fifth support ring, and the other second coil  273  is connected to the end connecting portion  2156  of the second support ring  2152  and the fourth support ring. Each second coil  273  is inserted into the gap between the strands of the respective support rings, so that the second coil  273  is fixedly connected to the first occluding disk  21   b . The tightening wire  25  passes through the threading hole  270  of the first coil  271  and the threading holes  270  of the respective second coils  273 . 
     As shown in  FIG.  10   , the structure of the first occluding disk  21   c  according to a still further embodiment of the present application is similar to the structure of the first occluding disk  21  according to one of the above embodiments, and the difference therebetween is that: the connecting member of the first occluding disk  21   c  includes one first coil  271  and six second coils  273 , wherein the first coil  271  is disposed at the geometric center of the first occluding disk  21   c , and the six second coils  273  are arranged around the geometric center of the first occluding disk  21   c  in an annular array by one round. In this embodiment, the end connecting portion  2156  of each adjacent two support rings  2151  is connected with a second coil  273 . Specifically, the end connecting portion  2156  of the first support ring  2151  and the third support ring  2153 , the end connecting portion  2156  of the first support ring  2151  and the fifth support ring, the end connecting portion  2156  of the second support ring  2152  and the fourth support ring, the end connecting portion  2156  of the second support ring  2152  and the sixth support ring, the end connecting portion  2156  of the third support ring  2153  and the fifth support ring, and the end connecting portion  2156  of the fourth support ring and the sixth support ring are respectively provided with a second coil  273 . Each second coil  273  is inserted into the gap between the strands of the respective support rings, so that each second coil  273  is fixedly connected to the first occluding disk  21   c . The tightening wire  25  passes through the threading hole  270  of the first coil  271  and the threading holes  270  of the respective second coils  273 . As shown in  FIG.  11   , the structure of the first support frame  215   a  according to the present embodiment is similar to the structure of the first support frame  215  shown in  FIG.  5    described above, and the difference therebetween is that: adjacent support rings penetrate each other at the connections within both the central region and the edge region. Specifically, the first support ring  2151  and the third support ring  2153  are located at opposite sides of the second support ring  2152 . The ends of the first support ring  2151  and the third support ring  2153  are connected with and penetrate each other, and the first sleeve  214  is spaced from the connection of the end of the first support ring  2151  and the end of the third support ring  2153 , with an eyelet defined therebetween. In this embodiment, the end of the first support ring  2151  is inserted into the gap between the strands of the end of the third support ring  2153 . In other embodiment, the end of the third support ring  2153  can be inserted into the gap between the strands of the end of the first support ring  2151 . Alternatively, a part of the strands of the end of the first support ring  2151  can be inserted into the gap between the strands of the end of the third support ring  2153 . Preferably, the support rings of the first support frame  215   a  penetrate each other at all the connections. 
     As shown in  FIG.  12   , the structure of the first support frame  215   b  in this embodiment is similar to the structure of the first support frame  215   a  shown in  FIG.  11    described above, and the difference therebetween is that: the second coil  273  passes through the eyelet  2158  formed at the connection where the first support ring  2151  and the third support ring  2153  penetrate each other. Specifically, four eyelets  2158   a ,  2158   b ,  2158   c ,  2158   d  are defined which are distributed in a clockwise direction at the connection where the first support ring  2151  and the third support ring  2153  penetrate each other, wherein the eyelet  2158   a  is opposite to the eyelet  2158   c , and the eyelet  2158   b  is opposite to the eyelet  2158   d . The eyelet  2158   c  is surrounded by first support ring  2151  and the third support ring  2153  and is located within the central region. The eyelet  2158   a  is further away from first sleeve  214  than the eyelet  2158   c . The eyelet  2158   b  and the eyelet  2158   d  are located at two sides of the eyelet  2158   a  and the eyelet  2158   c , respectively. The second coil  273  is inserted in the eyelet  2158   a  and the eyelet  2158   c , and extends across the connection of the first support ring  2151  and the third support ring  2153 , thereby preventing the second support ring  273  from being displaced on the first support frame. 
     In other embodiments, the first support frame  215  and the second support frame  235  each are generally braided from 4 to 50 support rings, with eyelets formed between adjacent support rings. Hereinafter, the first support frame  215  will be described as an example. The following description can also be applied to the second support frame  235 . The first support frame  215   c  as shown in  FIG.  13    is formed by thirty circular support rings circumferentially arranged around the axis of the first sleeve  214 . The first support frame  215   d  shown in  FIGS.  14  and  15    is formed by six circular supporting rings arranged in an annular array around the axis of the first sleeve  214 . The first support frame  215   d  shown in  FIG.  15    is provided with a first flow-blocking film  218 . 
     In other embodiment, each of the support rings can be elliptical, semi-circular, or irregularly shape, etc. As shown in  FIG.  16   , the first support frame  215   e  includes a plurality of oval-shaped support rings arranged in an annular array around the geometric center of the first sleeve  214 , wherein one end of each support ring is connected to the first sleeve  214 , and the inner surface and/or the outer surface of the first support frame  215   e  are provided with the flow-blocking film. As shown in  FIG.  17   , the first support frame  215   f  is formed by several semicircular support rings arranged in an annular array around the geometric center of the first support frame  215   f , wherein one end of each support ring is connected to the first sleeve  214 , and the inner surface and/or the outer surface of the first support frame  215   f  are provided with the flow-blocking film. As shown in  FIG.  18   , the first support frame  215   h  is formed by several irregularly shaped support rings arranged in an annular array around the geometric center of the first support frame  215   h , wherein one end of each support ring is connected to the first sleeve  214 , and the inner surface and/or the outer surface of the first support frame  215   h  are provided with the flow-blocking film. 
     The tightening wire  25  and the connecting member can use non-absorbable biocompatible sutures, such as metal wire, cotton thread, polyester, polypropylene and the like. Alternatively, the tightening wire  25  and the connecting member can use absorbable biocompatible sutures, such as catgut, polyglycolide, multi-filament non-biodegradable suture and the like. Alternatively, the tightening wire  25  can use forcibly wound fiber and the like. 
     In the present embodiment, the tightening wire  25  uses PTFE suture which is a material having good toughness and high mechanical strength. Alternatively, the tightening wire  25  can use biodegradable PGA, PGLA, PLA, collagen, nylon suture, polyester suture, and the like. The material of the connecting member  27  is a PP material which has a good tensile strength and hardness. Alternatively, the connecting member  27  can use PET, ePTFE or the material used for the above-mentioned tightening wire  25 . In this embodiment, the connecting member  27  is made of a suture with two strands, so that the occluder has a good connection strength. In other embodiment, the connecting member  27  can use suture with more strands, or suture with one strand. 
     In procedure, the occlusion system  100  of the present application is used in cooperation with a guide wire, the delivery device  50 , a dilator, and the like. The procedure is as follows: 
     1. Insert the guide wire into the left superior pulmonary vein, retain the guide wire and insert the delivery sheath and dilator into the middle of the left atrium, and withdraw the dilator and the guide wire. 
     2. Keep the delivery sheath still, insert the delivery rod of the delivery device  50  carrying the first occluding disk  21  and the second occluding disk  23  into the posterior end of the delivery sheath, push the delivery device forward, and push the anterior end of the delivery rod out of the delivery sheath. 
     3. Release the first occluding disk  21  relatively away from the handle  54  within the left atrium until the first occluding disk  21  is deployed within the left atrium; subsequently retract the delivery sheath with the delivery device  50 ; when the delivery sheath is retracted into the right atrium, release the second occluding disk  23  until the second occluding disk  23  is deployed in the right atrium; now the adjusting knot  250  is in a relaxed state, the base loop  2501 , the locking loop  2503  and the adjusting knot  250  are in a relaxed state, and the loops are not tightened. 
     4. Fix the second occluding disk  23  at the distal end of the delivery sheath, and pull the free end  2510  of the adjusting section  251  proximally by the delivery device  50  so that the centering section  254  is straightened and shortened in length, so as to drive the first occluding disk  21  and the second occluding disk  23  to move relative to the atrial septum until the inner side of the first occluding disk  21  abuts against the side of the atrial septum around the oval foramen, and the inner side of the second occluding disk  23  abuts against the other side of the atrial septum around the oval foramen. 
     5. When the atrial septum around the oval foramen is firmly clamped by the first occluding disk  21  and the second occluding disk  23 , pull the free end  2530  of the locking section  253  proximally by the delivery device  50  to gradually tighten the locking loop  2503  which will in turn drive the base loop  2501  to be tightened until both the locking loop  2503  and the base loop  2501  are tightened, so that the adjusting section  251  is tensioned and locked by the locking loop  2503  and the base loop  2501  and fixed between the locking loop  2503  and the base loop  2501 , and the length of the tightening wire  25  between the first occluding disk  21  and the second occluding disk  23  is fixed, thereby clamping the atrial septum between the first occluding disk  21  and the second occluding disk  23 . 
     6. After the knotting is completed, push the suture trimmer into the right atrium through the delivery sheath, cut the suture at a distance of 3-5 mm from the adjusting knot, and withdraw the delivery sheath and the suture trimmer, thereby achieving the occlusion of the oval foramen. 
     For convenience of description, numbers are used for the above steps of the method. However, it should be noted that the numbers are not used to limit the sequence among the steps. Without departing from the spirit of the present application, the specific technical solutions according to the above embodiments are applicable with each other. 
     The above embodiments are the implementations of the present application. It should be noted that several modifications and improvements can be made by those skilled in the art without departing from the principle of the embodiments of the present application. These modifications and improvements are also considered to be within the scope of the present application.