JPH0472547B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a new vascular prosthesis used as a connecting piece between blood vessels or a bypass, and particularly to a vascular prosthesis used for a bypass between a vein and an artery. It is about things.

BACKGROUND OF THE INVENTION In medical technology, vascular prostheses for connecting or bypassing blood vessels are used relatively often in analytical tests and drainage for blood purification. This type of bypass is left in the body for an extended period of time and is used as a drainage site for blood for various purposes. For example, the use of vascular prostheses or bypasses has become commonplace in so-called hemodialysis, which is performed on patients with impaired renal function, and in particular in blood purification in artificial kidneys, which is performed regularly every week. .

As vascular prostheses, generally used are heterografts, ie blood vessels taken from cows, sheep or pigs. These specially treated xenografts, called xenografts, are harvested from animals and treated with chemicals to allow them to remain in the body for long periods of time and to constitute tissue-compatible materials. Consists of physically or physically treated blood vessels. These bypasses are surgically connected at one end to an artery in the patient's arm and at the other end to a vein. This method connects two blood vessels. In this state, through the bypass formed, there is an intermittent drainage of blood, purification of the ejected blood and return of the purified blood to the blood circulation system.

[Problem to be solved by the invention] However, in order to connect arteries and veins,
When using conventional vascular prostheses, the following problems could occur.

For blood drainage, a bypass surgically inserted under the skin is pierced with a cannula. If drainage is repeated,
The bypass will lose its elasticity. on the other hand,
When removing the cannula after blood processing is completed, it is necessary to apply pressure to the drainage site in order to coagulate the blood, using a method similar to that used for drainage commonly used in blood analysis, etc. becomes. If the vascular prosthesis that makes up the bypass has lost its elasticity,
After external pressure is applied to the bypass to cause blood to coagulate, when the pressure on the bypass or vascular prosthesis is released, the bypass or vascular prosthesis may not return to its normal expanded state due to its lack of elasticity. Instead, it remains in a compressed state, which may disrupt blood circulation.

Another problem when using this type of vascular prosthesis is that when one end of the vascular prosthesis is surgically connected to a blood vessel such as a vein, blood flowing out from the bypass may cause damage to the blood vessels near the bypass site. It is about being influenced. Experiments have shown that venous narrowing occurs within a few centimeters from the connection site of the vascular prosthesis.

Therefore, an object of the present invention is to provide a vascular prosthesis that can solve the above problems.

[Means for Solving the Problems] Regarding the present invention, compared to the conventional method described above,
It has been found that it is possible to provide a vascular prosthesis consisting of a tubular component of tissue compatible material that has substantial advantages. The vascular prosthesis according to the invention comprises:
A support member having an elastic return force is provided inside the hollow tubular prosthesis main body, and this support member is provided to protrude by a predetermined length from at least one side end of the prosthesis main body. When the present invention is used for a permanent or long-term connection of an artery to a vein, the support member protruding from the prosthesis body expands when inserted into the vein to expand the vein from the inside. support,
Prevents narrowing of veins.

The prosthesis body is formed from tissue-compatible natural or synthetic materials. It is therefore possible to use, as the body of the prosthesis, the conventional materials used in xenografts from cows, sheep or pigs, which are known in the art. According to the invention, the prosthesis body is preferably formed by a xenograph prepared by special chemical or physical treatment of the xenograft and the substances present therein. It is also possible to form a prosthesis with a tissue-integrated material made of synthetic resin such as polyethylene terephthalate, polytetrafluoroethylene, polyethylene, polypropylene, or the like. However, it is particularly preferred in the present invention to use biological materials of the non-human xenograft type.

The support member inserted into the hollow tubular prosthesis body can be designed in various ways. For example, the support member can be configured as a helical spiral spring that applies a predetermined expansion pressure to the inner wall surface of the prosthesis. In this case, the material for forming the spiral spring may be tissue compatible stainless steel or plastic material having sufficient rigidity. Details of such spiral springs are described in detail, for example, in Swedish Patent Application No. 8202740-0.

In addition, the support member may be constructed of a tubular body having flexibility by braiding yarn elements having appropriate rigidity and flexibility and having an axis common to the central axis of the prosthesis body. is also possible. In this case, each yarn element constituting the tubular body is wound in one direction.
Consisting of one or more thread-like elements wound in the opposite direction to the thread-like elements, each thread-like element is wound in a spiral and is disposed at a predetermined distance in the axial direction with respect to the other thread-like elements. The thread-like elements intersect with other thread-like elements to form a braided structure. The tubular body formed with this braided structure has elasticity in the axial direction, reduces its diameter in the stretched state to facilitate insertion into the vein, and expands in the contracted state to come into contact with the inner wall of the vein. , this will be expanded and supported.

The diameter of the vascular prosthesis can vary within a relatively wide range depending on the application, but generally the diameter of the vascular prosthesis is 3.
The dimensions are ~10mm. The appropriate length of the support member protruding from the end of the prosthesis body is about 20 times the inner diameter of the prosthesis, but in order to obtain the desired function, it should be about 3 to 12 times the inner diameter of the prosthesis. is appropriate. With this method, the part protruding from the end of the prosthesis body can expand and support blood vessels such as veins that may be negative to atmospheric pressure, thereby preventing their narrowing. becomes.

By using the vascular prosthesis according to the invention, the problems of the prior art mentioned above can be easily and effectively overcome. In addition, the elastic restoring force of the support member housed within the prosthesis body ensures sufficient elasticity for the entire period in which the vascular prosthesis is left in the body. Therefore, blood drainage can be performed without any hindrance. In addition, if a spiral spring wound in the opposite direction is used, when the cannula is inserted into the vascular prosthesis, the spring material expands, and the cannula is removed and the support member returns to its reduced diameter. This provides the advantage that the prosthesis, which has been expanded by insertion of the cannula, can be contracted and brought into a sealed state almost automatically. In this case as well, stenosis of the vein can be prevented by inserting the portion of the support member protruding from the prosthesis body into the vein.

[Embodiment] The accompanying drawings schematically show a vascular prosthesis 1 according to an embodiment of the invention, in the illustrated example the vascular prosthesis 1 is coupled to an artery 5 and a vein 7 to bypass the vein and artery. It consists of The bypass or vascular prosthesis 1 has a helically wound spiral spring 3 as a support element. This spiral spring 3
is a protrusion that extends from the arterial joint end 9 of the prosthesis main body 2 formed into a hollow tube shape, passes through the prosthesis main body 2 to the venous end 11, and further projects a predetermined length from the venous end. The portion 13 is extended and inserted into the vein.

The prosthesis body 2 is preferably constituted by a xenograft formed of a xenograft taken from, for example, a cow and treated chemically and/or physically in an appropriate manner. The spiral spring 3 is made of stainless steel that is medically acceptable.

The method of use and insertion of the vascular prosthesis to connect the artery 5 to the vein 7 is as follows.

First, as a first step, a patient's vein is surgically incised, and then a prosthesis body 2 made of a xenograft is attached to the incision site of the vein using a conventional method. Next, the spiral spring 3 constituting the support member is inserted through the prosthesis body from the outside of the prosthesis body. In this case, by rotating the spiral spring 3 in an appropriate manner, it is inserted into the prosthesis main body 2 in a reduced diameter state, and the protrusion 13 is inserted into the vein as shown in the figure. At this position, the restriction on the spiral spring 3 is released and it is expanded, and the prosthesis main body 2 and the vein 7 are opened with a predetermined pressure.
The spiral spring 3 is fixed to the prosthesis body and the vein by abutting against the inner wall surface of the prosthesis body and the vein. Note that the length of the protrusion 13 inserted into a vein can be 3 to 4 cm when the vascular prosthesis of the present invention is used for hemodialysis.

After the spiral spring 3 is inserted into the prosthesis body 2, the spring 3 is cut at the other end (the end on the artery side) of the prosthesis body. Next, the patient's skin is incised, the vascular prosthesis is inserted under the patient's skin, and the other end of the prosthesis body is joined to the incised opening of the artery 5 by suture. In this example, since the blood in the artery is under pressure, it is unnecessary to provide a protrusion of the spiral spring that protrudes from the artery side end of the prosthesis body 2.

Once the vascular prosthesis has been installed, it can be easily held in place and easily penetrated for blood drainage.

The details of the spiral spring 3 used in the above embodiments are given in Swedish patent application No. 8202740-0.
Disclosed in the issue.

The structure of the support member is not limited to the one described above, and various structures may be adopted. For example, the support member may be formed of a tubular body formed by braiding a plurality of thread-like elements. It is possible. This tubular body has one or more thread-like elements with one winding direction and one or more thread-like elements with the opposite winding direction, respectively, in the axial direction with respect to the common axis with the prosthesis body. The tubes are arranged at predetermined intervals and are braided so that the diameter of the tubular body decreases when it is expanded in the axial direction and expands when it is contracted in the axial direction. Although various methods can be considered for expanding the diameter of the tubular body when it contracts in the axial direction, it is preferable to expand the diameter of the tubular body when the restricting force that restricts the tubular body to the extended state is released. The diameter is automatically expanded and restored by the elastic restoring force of the thread-like elements. This elastic restoring function can be achieved, for example, by using the tension of the filamentous element.

The function of the support member made of the tubular body described above is the same as that of the support member made of the helical spring described above.

The present invention is not limited to the structure of the embodiments described above, but includes various changes and modifications, and the present invention is also applicable to blood discharge for sample collection, analysis, dialysis, etc. It can be used for all applications that require interconnecting two blood vessels by creating a bypass. Furthermore, the method for attaching the vascular prosthesis is not limited to the above method, and any appropriate method may be employed. For example, it is also possible to insert a support member made of a helical spring or the like into the prosthesis body in advance with the protrusion 13 protruding, and connect it to the vein and artery in this state. In this case, the end on the side where the protrusion is provided is sutured to the vein with the protrusion inserted into the vein, and then the other end is coupled to the artery.

As mentioned above, according to the present invention, in addition to the above-mentioned advantages, when the vascular prosthesis is attached subcutaneously for use in hemodialysis, for example, the prosthesis does not bend like conventional vascular prostheses. It does not wobble or rotate and can always be held in a fixed position. In addition, by inserting the support member, sufficient elasticity is ensured in the vascular prosthesis, and the vascular prosthesis can be easily guided and used.

[Brief explanation of the drawing]

The figure is a perspective view schematically showing a vascular prosthesis according to an embodiment of the present invention that is indwelled in the body for a long period of time for periodic hemodialysis. 1... Blood vessel prosthesis, 2... Prosthesis main body, 3... Helical spring, 5... Artery, 7... Vein, 13... Protrusion part.

Claims (1)

[Scope of Claims] 1. A tubular prosthesis body formed of a material having tissue affinity, which is inserted into the prosthesis body and protrudes by a predetermined length from at least one side end of the prosthesis body, The support member has an elastic restoring force and has a protrusion that is inserted into the vein to which the one end is connected, and the support member has an elastic restoring force and is inserted into the artery with the corresponding end inserted into the vein to which the corresponding end is connected. and a vascular prosthesis, characterized in that it connects veins to form a bypass. 2. Claim 1, wherein the prosthesis body is comprised of a xenograft taken from a cow, sheep, or pig.
Vascular prosthesis described in section. 3. The vascular prosthesis according to claim 1, wherein the prosthesis body is composed of a xenograft. 4. A vascular prosthesis according to claim 1, wherein the prosthesis body is formed of a synthetic material. 5. The vascular prosthesis according to any one of claims 1 to 4, wherein the support member is a helical spring that comes into contact with the inner wall of the prosthesis body with a predetermined pressure to ensure a predetermined expansion force. . 6. The support member is composed of a tubular body formed by braiding a plurality of thread-like elements having appropriate rigidity and flexibility, and the thread-like elements are wound in one winding direction. One or more first thread-like elements and one or more thread-like elements wound in the winding direction of the first thread-like element are arranged at a predetermined interval in the axial direction and intersect with each other. A vascular prosthesis according to any one of claims 1 to 4. 7 The protruding length of the protrusion from the end of the prosthesis body is about 20 times the diameter of the prosthesis body, preferably 3 to 3.
A vascular prosthesis according to any one of claims 1 to 6, which is 12 times as long.