JPS61360A - Freely deformable canula - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new type of cannula, and more particularly to a new deformable cannula for use in cardiac surgery.

BACKGROUND OF THE INVENTION Conventionally, a cannula for an artificial heart-lung machine has been used during heart surgery.

The present invention provides a new cannula developed for a completely new type of heart surgery different from conventional heart surgery techniques, namely, an artificial heart or an auxiliary artificial heart (hereinafter collectively referred to as an artificial heart). .

Although the average lifespan of humans is increasing year by year with advances in medicine, the proportion of causes of death from heart disease is increasing year by year. Among heart disease patients, artificial hearts are being used as a new treatment to save patients with chronic congestive heart disease, acute myocardial infarction, and post-surgical low cardiac output syndrome, which are difficult to survive with conventional surgical methods. Development is underway. However, artificial hearts have not yet been commercially available, and only a few clinical cases have been seen so far at several research institutes worldwide that are conducting research and development of artificial hearts. Various types of artificial hearts are being developed, but any type of artificial heart must have enough heart function to become a total artificial heart, and in the meantime, in order for cardiac surgery to be successful for critically ill patients, the patient's own In order to assist the heart until it functions normally and to play its role in saving patients' lives, a special cannula for an artificial heart that does not previously exist must be developed. Even if you use a cannula used in
Moreover, since the shape does not correspond to the shape of the heart, there is a problem in that the function of the artificial heart cannot be fully demonstrated. In order for an artificial heart to function adequately, the first thing required is a cannile shape.The patient's heart is located in the narrow space between the pleural cavities and beats constantly. There are two types of cannula. One is the blood removal cannula. This is a cannula that drains blood from the right atrium, vena cava, or left atrium and guides it into the artificial heart.
The other is a blood supply cannula that connects the artificial heart to the pulmonary artery or aorta. All of these cannulae need to be short so that they do not restrict movement of the patient's heart, bypass the constantly active heart, and have as little pressure drop as possible. For this reason, a special way of bending and shape of the crab is required.

Moreover, it is necessary that the curved portion of the cannula does not cause pulsation or kinking phenomenon due to blood pulsation.

Furthermore, the shape of the cannile must be widely applicable. This is because there are a wide variety of patients, including patients, children, men, and women.
In particular, the hearts of people with heart disease exhibit an abnormal enlargement commonly referred to as cardiomegaly, and the appearance of this phenomenon differs from person to person.There are no cannulae that have been widely applied to these various shapes of hearts. However, in order to actually use an artificial heart, these requirements must be met. Further, it is preferable that the inner diameter on the side of the connecting portion with the artificial heart is larger than a certain value. If this part does not have an inner diameter of a certain size or more, pressure loss will occur before the blood pumped from the artificial heart reaches the aorta blood vessel or pulmonary artery blood vessel, which will drastically reduce the function of the artificial heart, which is undesirable. A patient's heart is located in the space between the pleural cavities, in which the heart beats vigorously. If the cannula is too thick over its entire length, it may be difficult to use it for treatment.
- This puts full pressure on the heart, restricts the movement of the heart, and reduces the function of cardiac support. Therefore, an ideal cannula for an artificial heart must be longitudinally deformable and have an appropriate inner diameter. Additionally, the cannula must not bulge in a pulsating manner in response to sudden pressure ejection from the heart during use. This is because the pressure of extraction from the heart reaches as much as 2aa11 mmy, and this pressure is a vigorous beat of 60 to 120 times per minute. If,
If the cannula deforms as blood is extracted from the artificial heart, the deformation absorbs the pulsating flow of blood, impairing the full functionality of the artificial heart. Therefore, it is necessary that the entire cannula is free from pulsating deformation due to pulsation of blood flow during surgical use.

Note that it is desirable that the length of the cannula can be adjusted instantaneously during surgery. This is because, as already mentioned, the shapes of patients' hearts vary widely, and when using an artificial heart, a cannula whose length can be adjusted is desirable from the standpoint of performing surgery. As mentioned above, the blood removal cannula is used to remove blood from the patient's left atrium and guide it to the artificial heart when the artificial heart is used for left heart assistance or replacement.
Blood pumped from the artificial heart is sent to the ascending aorta by a blood feeding cannula. The above-mentioned surgical method is considered to be the most widely used method when using an artificial heart to assist cardiac function.Many researchers have developed many surgical methods using an artificial heart. Although it is growing,
In terms of actual surgical cases, cases in which the patient's left heart is assisted are thought to account for most of the cases. In this case, the blood removal method most desired by cardiac surgeons is to insert a cannula into the left atrium from the interface between the pulmonary veins and the right atrium on the dorsal side of the patient's heart, as shown in Figure 5. Blood is removed from the left atrium or cannulated from the left atrial appendage. In case B, the cannula needs to be shaped so that it goes around the patient's heart to the front side of the heart, as short as possible, and does not interfere with the movement of the patient's heart.

The present invention is a special cannula newly developed in response to such demands, and is an artificial cannula in which the tube section from the insertion tip of the cannula to the other end is reinforced with a spiral or ring-shaped reinforcing material. Composed of blood vessels,
The inner surface of the artificial blood vessel is preferably coated with polyurethane or an antithrombotic material based on polyurethane, so that it can be freely bent in three dimensions along the length of the cannula. Q: In order for the artificial heart mentioned above to perform its functions, it must be inserted into the desired position of the left atrium as quickly as possible without interfering with the movement of the patient's heart. It is necessary to have a special cannulae that can be freely bent in three dimensions. Another feature of the present invention is that the distal end of the cannulae is attached to a fitting for insertion or for anastomosis to a living body. On the side of the cannula connected to the artificial heart, there is an orthosis (tube made of polyvinyl chloride, polyurethane, epoxy resin, etc. connector). Furthermore, at least the inner surface of the artificial blood vessel is coated with an antithrombotic material, and the fitting for insertion of the tip of the cannula, the connecting device to the artificial blood vessel graft for anastomosis, and the artificial heart boat part are also coated with an antithrombotic material.
It is preferable that the surface of the foreign material connected to the artificial blood vessel be coated seamlessly with the anti-thrombotic material so that the entire inner surface is seamlessly coated with the anti-thrombotic material.

The deformable cannula according to the present invention, for example, as shown in FIG. This allows for easy bending through the vicinity of the midline sternotomy line to reach the artificial heart, and can be configured according to the condition of the patient. The degree of bending is very important, and if it is not appropriate, various problems will occur. In other words, if these curves are too steep, they will put pressure on the heart's movement, and if the curves are too steep, they will
,) If the cannula is insufficient and has little bending, too much force will be applied to the insertion joint with the patient's heart, which may cause the distal end of the cannula to come off, and there is also a concern that it may put pressure on the patient's lungs. The cannile according to the present invention uses an artificial blood vessel reinforced with a spiral or ring-shaped reinforcing material that can be freely deformed in three dimensions, so it can be easily deformed depending on the intended purpose and can be used quickly. It also has the characteristic that it does not undergo deformation due to movement or kinking (bending phenomenon).

The material for the artificial blood vessel part that makes up the cannile is, for example, various tubular fabrics (including felt, woven, knit, velor, etc.) made of polyethylene terephthalate (l/-) fibers, and so-called KPTF'E. (Expanded
Foly tetrafluoroethylene'
A tubular body of polyfluorinated ethylene such as (no) is used.

Further, these artificial blood vessel sections are reinforced on the outer or inner surface with a ring-shaped or spiral-shaped reinforcing material made of synthetic resin such as polypropylene or gold 114, thereby providing kink resistance.

As shown in Figures 1 to 4, the tip of the cannula +11 is attached to an artificial blood vessel for anastomosis (2) (without external reinforcement) and an insertion type fitting (2A)', which have external reinforcement. It is made integrally and continuously with the cannula main body, or is made through a connector (6) made of polyvinyl chloride (possible porcelain).The connection part with the artificial heart is a one-touch connector (4). Alternatively, it may be connected to a polyvinyl chloride tube (4A) plasticized with a sizing agent.

In any case, the tip is connected to an artificial blood vessel (2) for anastomosis to a living body (a part of the heart or a blood vessel) or a preferably porous brace (2) made of polyvinyl chloride for insertion, A device (4) or (4A) that has a ring-shaped or spirally reinforced artificial blood vessel part (3) connected to this distal device, and is connected to the artificial heart pump main body at the other end.
) is necessary. The material of this deformable artificial blood vessel is preferably one made of the above-mentioned tetrafluoroethylene polymer, especially the so-called 1!1 whose inner surface is fibrillated.
xpanaea poly tetrafluoro
Ethylene (KPTFFi) is preferred.

It may also be a woven fabric made from fibers made of polyethylene terephthalate, ie, woven, knitted, and bell gamma fabrics using Tetron (2) or Dacron (2).

The significance of coating the inner surface of the artificial blood vessel with a polyurethane-based antithrombotic material, which is a feature of the present invention, will be explained.

When an artificial blood vessel comes into contact with blood, a thrombus is first formed on the inner surface, and subsequently, fibroblasts infiltrate and proliferate from the outside of the blood vessel and from the host blood vessel, and fibroblasts with high differentiation potential are observed during blood flow. The a cyst implants and proliferates, and a new membranous substance consisting mainly of fibrin and collagen fibers is formed on the inner surface of the artificial blood vessel.

These are called pseudointima or neointima, and eventually endothelial cells are generated and become an antithrombotic membrane. However, it actually takes 4 to 8 weeks for the inner surface of the artificial blood vessel to become an antithrombotic membrane.

When an artificial heart is used, it may be used for a long period of time, but as an auxiliary heart it is only used for a few hours to 15 days at most. (Rather, it corresponds to the period when a thrombus layer is formed on the inner surface of the artificial blood vessel.The formed thrombus is not necessarily stably implanted and may fall off.
This can become an embolus and cause kidney damage or occlusion of cerebral blood vessels. Although the artificial blood vessel used in the present invention has the characteristic of being freely three-dimensionally deformed, it is desirable that the inner surface of the artificial blood vessel does not generate any thrombus. The present invention solves this problem, and the antithrombotic material must be able to freely adapt to deformation and have elasticity. There is a reason why this is preferable.

The inner diameter of the cannile of the present invention is preferably between 3 and 16 mm. If it is less than 311, it is too thin even for infants, causing a large pressure drop and causing problems in introducing blood into the artificial heart.
If it is larger than 1 m, it is undesirable because it puts pressure on the patient's heart.

The length can be freely configured from 10mm for infants to 40mm for adults.

The device for inserting the tip (2A) and the tube for connecting to the artificial heart (4A) are preferably made of plasticized polyvinyl chloride, and in this case, as a plasticizer for the polyvinyl chloride, known dioctyl phthalate, dioctyl adipate, etc. Polyvinyl chloride plasticizers are widely used. In this case, the flexible polyvinyl chloride may be molded from a so-called polyvinyl chloride paste consisting of polyvinyl chloride and a plasticizer composition.

In this case, the amount of plasticizer mixed is preferably 40 to 100 times the amount of polyvinyl chloride, and more preferably 50 to 80% by weight. stabilizers, such as non-toxic calcium
It may also contain a zinc-organic composite plate or the like. It is preferable to use polyvinyl chloride having a degree of polymerization of 500 to 2,000.

As described above, the antithrombotic material used in the present invention is preferably a polyurethane-based material, and polyester polyurethane and polyether polyurethane are both used, but polyether segment polyurethane is preferable in terms of antithrombotic properties. is preferably used. Particularly preferred are polyether-based segmented polyurethanes containing polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polydimethylsiloxane, etc. as soft segments. Polyurethanes and polyurethane ureas whose chains are extended using diol compounds and diamine compounds using isocyanates, 4,4' dicyclohexylmethane diisocyanates, etc. are preferably used.

Further, a copolymer of polyurethane and polydimethylsiloxane or an antithrombotic material containing polyurethane and polydimethylsiloxane as constituent components is used. In this case, an antithrombotic material may be used in which polydimethylsiloxane is the clear independent phase (island phase) and polyurethane is the continuous phase (channel phase). Such an antithrombotic material can be prepared by dispersing a polysiloxane having a terminal OR or terminal 4HocoaH group in a solution of polyurethane, and applying silane coupling such as methyltriacetoxysilane in the presence of an appropriate amount of water. Dispersed polydimethylsiloxane particles (1 μ~
60 μ) Stabilized by cross-linking the surface and simultaneously entangling polyurethane molecules into the cross-linked network. c emulsion may be used.

In addition, a difunctional or hexafunctional silane coupling agent activated by water, such as a mixture of dimethyldiacetoxysilane and methyltriacetoxysilane, is mixed into the polyurethane solution in an anhydrous state to form a bath liquid, and this is then mixed into a solution. Alternatively, during coating, finely distributed polysiloxane may be formed on the surface by reacting with moisture to form a so-called mutually flowing network structure (PN).

These antithrombotic materials are polyurethane-based and have elasticity, so they can freely bend the entire artificial blood vessel without any problems, suppress the adhesion of platelets in the blood, and prevent the formation of blood clots. be. As mentioned above, it is necessary that the antithrombotic material be applied at least to the inner surface of the artificial blood vessel.

The present invention will be explained in more detail below based on examples.

J Example ゛Reinforcement material (5) made of polypropylene strings is made of EPTFB reinforced by spirally wound inner diameter 10! l
A stainless steel rod (mold) was inserted approximately 1011 degrees from the end of the artificial blood vessel (3) at 1N. At this time, the flare between the metal rod and the artificial blood vessel was set to be about 11. This was heated as it was in a 200°C heater for 10 minutes, and the artificial blood vessel part was 5111 to 10% in a paste sol containing a heat stabilizer containing 70 parts by weight of dioctyl phthalate per 100 parts by weight of polyvinyl chloride. Insert it vertically so that it is immersed in IIN, and when it is pulled out after 5 minutes, the paste sol becomes a semi-gel and adheres to the artificial blood vessel. This was cured for 15 minutes at 200°C to completely integrate with the artificial blood vessel (Fig. 1 and Rattan Fig. 4). The tip (2) was processed using a conventional method, and the side hole (8) was drilled. Boxwood (7) can be attached (Figures 6 and 4) 0 The other end can be processed in exactly the same way as the PVC tube (4A
) can also be connected (Figures 2 and 3) (filling the contact area with paste sol and curing that area),
One-touch connector +41t- connection (Fig. 1 and 4)
Figure) can also be done.

The interior of the cannula thus formed is coated with an antithrombotic material, and an example of the synthesis of the antithrombotic material used in this example is shown below. That is, tetrahydronerane-dioxane (2
:1)'t-Dehydrated to make water content 400 ppm, and dissolved segmented polyurethane (Goodrich 5714) to make a 12% solution. This polyurethane is a polyether polyurethane whose soft segment is polytetramethylene glycol. Add to this the molecular weight 3 Q, OQ
Add 10 parts by weight of polydimethylsiloxane having a terminal hydroxyl group of O to 100 parts by weight of polyurethane, stir to disperse, and then add 2 parts by weight to 100 parts by weight of polyurethane using methyltriacetoxy7silane, and add 5 parts by weight at room temperature. The mixture was stirred for several days. The product is a milky white, stable emulsion with polydimethylsiloxane particles averaging 5 microns, the surface of which is crosslinked and entangled with polyurethane molecules.

This emulsion was filled into the cannula and then drained and air-dried. By this operation, the crab-
The inner surface of the tube is covered with this antithrombotic material.

Example 2 As shown in FIG.
FF: A manufacturing method for making an artificial blood vessel, in which the paste sol is applied to each of the outer surfaces of both ends of a pre-formed soft polyvinyl chloride tube (length 30n11) for about 10 cm from the tip, and then applied on top of the paste sol. , an artificial blood vessel (3) reinforced with six-ring-shaped polypropylene strings (5), and an artificial blood vessel (2) reinforced with the above-mentioned tube from above, respectively, so that the length of the overlapped portion is 10 It was a crane. At this time, make sure that the paste sufficiently penetrates into the fibril portion of EPTFE. By curing this at 200° C. for 2 hours, complete integral molding can be achieved as shown in FIG.

The inner surface of this cannula was completely coated with an antithrombotic material, and the antithrombotic material used in this example was prepared as follows.

Tetrahydro7rane=dioxane (1:1)' to 1 part water
Dehydrated to below 0 ppm. To this, a prepolymer was made from polyethylene glycol (molecules [1000) and 414' diphenylmethane diincyanate, and 11% polyether polyurethane was obtained by chain-extending it with butanediol.
Comb to form a solution and add 8% to this polyurethane.
% of a silane compound (diacetoxydimethylsilane-triacetoxymethylsilane (8:2 mixture)) was added to form a homogeneous and transparent solution.

This solution was filled inside the molded cannile and immediately allowed to flow freely to coat the inner surface, air-dried in an atmosphere of RH 60%, and the silane compound was activated and condensed with the moisture in the entire atmosphere.

In this way, a polyurethane-based antithrombotic material was coated on the inner surface.

Example 3 The artificial heart was set using a full-size model of the heart, and the cannula prepared in Examples 1 and 2 was inserted into the narrow thoracic cavity by fitting into the complex shape around the heart. When we examined the fit, we found that it fit perfectly, as shown in Figure 5.

Example 4 Using the cannulae of Examples 1 and 2, a left heart bypass experiment was conducted using goats. Four weeks later, when the inside of the tube was examined, no blood clots were found.

Similar results were obtained whether Biomer (Ethicon) or a purified product of polyether polyurethane Nisten 5714 (Gutdrich) was used as the antithrombotic material.

As explained above, since the cannula according to the present invention can be freely deformed, it can be adapted to various patient conditions and usage conditions, and can also be smoothly connected to an artificial heart, unlike the conventional straight cannula. - This is a brilliant solution to problems that could not be implemented with other devices (for example, those for artificial lungs).
'And by coating the inner surface with antithrombotic material, the occurrence of blood clots is also prevented.

[Brief explanation of drawings]

FIGS. 1 to 4 are partially cutaway perspective views of the cannula according to the present invention, and FIG. 5 shows an embodiment in which the cannula according to the present invention is used together with an auxiliary artificial heart during heart surgery. FIG. Patent applicant Zeon Corporation Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. The distal end to be attached has a fitting for insertion or an artificial blood vessel graft for anastomosis, the other end is equipped with a device for connecting to an artificial heart, and the main tubular part extending between these ends has a spiral or A deformable cannula comprising an artificial blood vessel reinforced with a ring-shaped reinforcing material, the artificial blood vessel having at least its inner surface coated with an antithrombotic material.