Valved stent, base material for forming valved stent, and method for producing valved stent

Abstract

The present invention provides a valved stent that can provide a valve function without blocking a branch blood vessel, and also can provide a valve function with minimum covering of blood vessel tissue in a stent indwelling section. Specifically, a cylindrical stent body 4 is provided. A leaflet 5 that can open/close a blood vessel 2 in a blood flow direction is provided. The leaflet 5 is composed of connective tissue and protrudes radially inward from the stent body 4 . An inside and an outside of the stent body 4 radially communicate with each other. The stent does not block a branch blood vessel 8 . An area of the blood vessel covered with the stent is reduced.

1 . A valved stent indwelled in a blood vessel to provide a valve function to the blood vessel, comprising:
 a cylindrical stent body; and   a leaflet composed of connective tissue that protrudes radially inward from the stent body and is capable of opening/closing the blood vessel in a blood flow direction,   wherein an inside and an outside of the stent body radially communicate with each other.   
     
     
         2 . The valved stent according to  claim 1 , wherein the stent body is a mesh-like metal member. 
     
     
         3 . The valved stent according to  claim 1 , wherein the stent is capable of being indwelled in an ampulla with a blood vessel wall of the blood vessel expanding radially outward, and the stent body is set to a length such that the stent body is capable of spanning the ampulla in the blood flow direction and being held on opposite sides. 
     
     
         4 . The valved stent according to  claim 1 , wherein a plurality of the leaflets are arranged in parallel in a circumferential direction of the stent body, and the plurality of leaflets are integrated at a base end. 
     
     
         5 . The valved stent according to  claim 1 , wherein a contact section that covers the stent body and comes into contact with the blood vessel wall is composed of connective tissue, and a plurality of the contact sections are continuously formed in the blood flow direction at intervals in the circumferential direction of the stent body to expose the stent body between the plurality of contact sections. 
     
     
         6 . The valved stent according to  claim 5 , wherein the contact section is formed so as to be aligned with a boundary between the plurality of leaflets in the circumferential direction of the stent body. 
     
     
         7 . A base material for forming a valved stent that is placed in an environment with a body tissue material to form film-like tissue on a surface of the base material and form a valved stent including a leaflet protruding radially inward from a stent body, comprising:
 a columnar base material body;   a plurality of recesses formed in an outer peripheral surface of the base material body;   an inner cover that covers the recesses to form a leaflet forming space for forming the leaflet; and   an outer cover placed on an outer surface side of the inner cover with the stent body interposed therebetween.   
     
     
         8 . The base material for forming a valved stent according to  claim 7 , wherein the inner cover and the outer cover have open sections that expose a boundary between the plurality of recesses in the outer peripheral surface of the base material body via the stent body. 
     
     
         9 . The base material for forming a valved stent according to  claim 7 , further comprising a positioning section that circumferentially positions the base material body, the inner cover, and the outer cover. 
     
     
         10 . A method for producing a valved stent comprising:
 an assembly step of assembling a base material for forming the valved stent according to  claim 7  by incorporating a stent body between an inner cover and an outer cover;   a placement step of placing the base material for forming the valved stent in an environment with a body tissue material;   a formation step of forming film-like tissue around the base material for forming the valved stent;   a taking-out step of taking out the base material for forming the valved stent covered with tissue from the environment; and   a separation step of integrally delaminating and taking out tissue including the leaflet and the stent body from the base material for forming the valved stent as a valved stent,   wherein the separation step is a step of removing tissue on surfaces of opposite ends of the base material for forming the valved stent and the outer cover, detaching the outer cover, and then central-axially disassembling and taking out the base material body and the inner cover from a lumen of the valved stent.   
     
     
         11 . A base material for forming a valved stent that is placed in an environment with a body tissue material to form film-like tissue on a surface of the base material and form a reverse valved stent with an inside and an outside being reversed of a valved stent including a leaflet protruding radially inward from a stent body, comprising:
 a columnar base material body; and   a base material cover placed on an outer peripheral side of the base material body with the stent body interposed therebetween.   
     
     
         12 . The base material for forming a valved stent according to  claim 11 , wherein the base material cover has an open section that exposes the outer peripheral surface of the base material body via the stent body. 
     
     
         13 . The base material for forming a valved stent according to  claim 12 , wherein the outer peripheral surface of the base material body has an entry groove that connective tissue enters, and the base material cover is placed so that the entry groove is aligned with the open section. 
     
     
         14 . The base material for forming a valved stent according to  claim 11 , wherein the base material cover has a bulge formed by expanding an outer surface side. 
     
     
         15 . A method for producing a valved stent comprising:
 an assembly step of assembling a base material for forming the valved stent according to  claim 11  by incorporating a stent body between a base material body and a base material cover;   a placement step of placing the base material for forming the valved stent in an environment with a body tissue material;   a formation step of forming film-like tissue around the base material for forming the valved stent;   a taking-out step of taking out the base material for forming the valved stent covered with tissue from the environment; and   a separation step of integrally delaminating and taking out tissue including the leaflet and the stent body from the base material for forming the valved stent as a reverse valved stent,   wherein the separation step is a step of removing tissue on opposite ends of the base material for forming the valved stent, then central-axially disassembling the base material body and the base material cover, taking out the base material cover from between the leaflet and the stent body, and taking out the base material body from a lumen of the reverse valved stent, and   the method further comprises, after the separation step, a reverse step of reversing an inside and an outside of the reverse valved stent to form a valved stent.