JPH0614941B2 - Multi-branch vascular prosthesis for coronary artery bypass - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an artificial blood vessel for aorta-coronary artery bypass.

[Outline of Invention]

The present invention relates to an artificial blood vessel for aorta-coronary artery bypass, wherein a large-diameter portion having an end portion having a diameter of 6 mm to 20 mm and a branch pipe having an inner cavity communicating with and branching from the large-diameter portion are integrally formed, and the distal end of the branch pipe is formed. By providing a portion having a taper in the branch pipe so that the caliber has a caliber of 1 mm to 4 mm, narrowing or blockage of the blood vessel is prevented.

[Conventional technology]

Even with the recent remarkable development of medical care, the number of deaths due to heart disease has been increasing year by year, making it the leading cause of death in the United States and the third leading cause of death in Japan.
Occupies the top rank and tends to increase year by year. 55 heart disease deaths per year in the US
It is said to have reached the number of all, most of which is due to the narrowing of the coronary arteries. To save these people, more than 200,000 aortic-coronary bypass operations are performed each year in the United States. Usually, the saphenous vein of the patient is transplanted to the aorta-coronary artery bypass, the main reason for this is that with commercially available artificial blood vessels with a diameter of 5 mm or less used for coronary artery bypass, vascular narrowing or This is because it causes blockage.

Therefore, the current situation is to transplant the patient's own saphenous vein, which has achieved considerable success.

[Problems to be solved by the invention]

However, patients who have succeeded in transplantation of the saphenous vein as an aorta-coronary artery bypass have come to have to perform re-operation again after the transplanted blood vessels have narrowed in 4 to 6 years. In such a case, the patient is using the saphenous autologous vein in the first operation and no more veins are needed for reoperation. Therefore, such a patient cannot be re-operated and the lifesaving route is cut off.

In addition, a significant number of patients with coronary artery disease have poor quality of the saphenous vessels, none are available, or sufficient length cannot be obtained, so a blood vessel for aorta-coronary artery bypass is obtained. I can't. Therefore, such a life-saving method for patients is closed.

The present inventor has advanced the development of a good quality aortic-coronary artery bypass graft material in order to save the life of such a patient, and arrived at the present invention.

Currently, artificial blood vessels mainly made of knitted and woven polyester fibers and those made of so-called PTFE (polytetrafluoroethylene), which is stretched and fibrillated with a fluororesin, are used.

After transplantation, these artificial blood vessels undergo plasma protein adsorption, platelet deposition, coagulation factor activation, and fibrin deposition, and the deposited fibrin is replaced by cells. The artificial blood vessel is required to have an appropriate porosity (porosity). But the aorta-
A blood vessel for bypassing the coronary artery requires an artificial blood vessel with an inner diameter of 5 mm or less, usually 4 mm to 3 mm.
It can be said that the following artificial blood vessels do not cause stenosis or blockage of blood vessels after transplantation.

The inventor has found that most of the causes of the stenosis and occlusion are caused by the anastomosis with the host blood vessel, and whether the anastomosis is good or bad has a great influence on the results of patency of the transplanted artificial blood vessel.

[Means for solving problems]

Obviously, the technique of anastomosis has superiority and inferiority to the operator's suturing technique, but it goes without saying that as the diameter of the blood vessel to be sutured becomes smaller, the anastomosis is more difficult. The present invention advances earnest research on the development of an artificial blood vessel for aorta-coronary artery bypass, and in order to improve the patency of the transplanted blood vessel, the diameter of the anastomosis at one end is
That is, the end on the side of anastomosis to the ascending aorta is 6 mm to 20 mm in diameter.
mm, branching into 2 branches, 3 branches, and 4 branches from this relatively thick blood vessel, and devising to make the end of this branch tube 1 mm to 4 mm in diameter to match the thickness of the coronary artery to be transplanted. The present invention has been achieved.

The saphenous vein of the patient is currently used as a blood vessel for aorta-coronary artery bypass. In most cases, an appropriate length of blood vessel is cut from the patient's saphenous or femoral vein and used as a blood vessel for aortic-coronary artery bypass, but for patients with coronary stenosis, usually only one bypass is required. In many cases, it is necessary to bypass two or three branches.

FIG. 5 shows an example of a conventional two-support bypass. In most cases, bypass surgery usually involves two or three branches. In this case, a thin blood vessel having a diameter of 3 mm to 4 mm must be sutured to the aorta twice at two places. Therefore, an anastomosis occupies a considerable area of the ascending aorta. In such a case, even if you try to save life by applying a supplemental artificial heart to the patient,
There is no place to insert a cannula for introducing the pumped blood on the aorta side of the artificial heart, and it becomes impossible to apply the auxiliary heart. Further, in this method, since the transplanted blood vessel is thin, the anastomosis technique is difficult, and the possibility of thrombus generation due to inadequate suturing increases. Further, in the case of a two-support and three-support bypass, the same operation has to be repeated twice or three times, which requires double or triple labor, which increases the burden on the patient.

The present inventors have reached the present invention by conducting various studies to solve these problems, to develop an artificial blood vessel that is easy for an operator, reduces the burden on the patient, and has less trouble after transplantation. The main point is an artificial blood vessel for aorta-coronary artery bypass, in which a large-diameter portion having an end portion with a diameter of 6 mm to 20 mm and a plurality of branch pipes with which the lumen communicates and branches A multi-branch artificial blood vessel for coronary artery bypass, characterized by having a tapered portion between the large diameter portion and the end of the branch pipe so that the end of the branch pipe has a relatively small diameter. is there.

The number of branch pipes according to the invention is between 2 and 6, preferably 2
-4, more preferably 2 or 3. In the artificial blood vessel of the present invention, the portion to be sutured to the aorta has an inner diameter of 6 mm to 20 mm, preferably 8 mm to 15 mm, more preferably 9 mm to
It is 13 mm. That is, if it is less than 6 mm, it may be difficult for the anastomosis technique to narrow the lumen in the blood clot, and if it is more than 20 mm, it is difficult to suture to the aorta and is too thick, which is not preferable.

The blood vessel according to the present invention has a narrower diameter toward the side of the coronary artery graft, but may be tapered substantially uniformly over the entire length, or may continue to have a relatively large diameter up to a certain length,
The taper may be tapered from the middle, or may be tapered anywhere from the aortic anastomosis side to the coronary anastomosis side. The diameter of the end of the branch tube on the coronary artery side is 1
It is from mm to 4 mm, preferably from 2 mm to 3 mm. As a result, anastomosis to the coronary arteries is difficult regardless of whether it is thin or thick, and the graft vessel is often occluded due to its inadequacy.

FIG. 1 shows a first example of the present invention.

An example of this is a bifurcated blood vessel that is bifurcated. The large diameter portion has a diameter L ₁ of 10 mm, and this thickness continues to the branch portion. This branching is actually very important, and it is necessary that the inner surface forming the lumen has no step and is smoothly connected. The angle θ (first
In the figure, 90 ° or less, preferably 70 ° or less, more preferably 60 °. It is desirable that θ is 10 ° or more. The luminal surface must be smooth with no steps. In this example, the diameter L ₁ on the large diameter side is 10 mm,
The longest diameter L ₂ of the branching portion is inflated to 16 mm, and the branching pipe after branching has two tapered tapers A ₁ and A ₂ with an inner diameter l ₁ of 8 mm. Has a diameter l ₂ of 2 mm and a branch pipe length of 1
It is 3 cm.

FIG. 2 shows a second example of the present invention. In this example, there are three branch blood vessels branched into three, and the tip diameter L ₃ on the large diameter side is 12
mm, and it is branched into 3 branches at 5 cm from this tip, and at this branch point, the diameter L ₄ is 21 mm at the longest.
The caliber l ₃ of the branched branch pipes is 7 mmφ. The 7 mmφ pipe has a length of about 35 mm, and the tapered pipes A ₃ , A ₄ , and A ₅ have tapered ends, and the diameter l ₄ of the tip of the branch pipe is 2 mm, and the length of each branch pipe is 15 mm.
cm. The branch tubes have a smooth curvature in the same direction and are designed to be convenient for bypass surgery.

FIG. 3 shows a third example of the present invention. This example also has three branch vessels that branch into three, but unlike the second example, there are two branch points, and each branch point forms a branch tube. In this example, the tapered tapers A ₆ , A ₇ ,
A ₈ is the middle of the branch pipes is provided per the middle of the branch pipe, both ends are of constant diameter. Branching in this manner is preferable because there is no difficulty in the blood flow in the blood vessel.

The branched multi-branch tubes of FIGS. 2 and 3 illustrated here are bent in the same direction with smooth curves. Such an appropriate curvature facilitates bypass surgery along the heart of the patient to be operated, which is convenient.

The tapered portion of the branched branch pipe may be formed in a tapered shape from the branching point to the tip as shown by A ₁ , A _{2 in} FIG. ₁ , and A ₃ , A ₄ , A ₅ in FIG. The intermediate portion between the branch point and the tip of the branch pipe may be formed in a taper shape as indicated by A ₆ , A ₇ , and A ₈ in FIG.

Note that A ₁ , A _{2 in} FIG. ₁ and A ₃ , A ₄ , in FIG.
A _5, if the length of the tapered portion indicated by _{A 6, A 7, A 8} of FIG. 3 and _{A x,} length _{A x} of the tapered portion
And it is desirable that the length _{l 0} of the large diameter side _{(l 0} shown in FIG. 1-FIG. 8) is the relationship _{4l 0 ≧ A x ≧ l 0} /4.

If the length A _x of the tapered portion (a steep taper) shorter than l _0/4 and abrupt changes in blood flow velocity taper portion thereof, such as resulting in exfoliation of cells formed in the artificial blood vessel inner surface As a result, it may cause thrombus formation.

Further, since the required total length of the artificial blood vessel is limited to some extent, the length A _x of the taper portion of the total length of the artificial blood vessel is more than 4l _{0 with} respect to the length l ₀ on the large diameter side. If the length is increased, the length on the large diameter side of the entire artificial blood vessel becomes short, and it becomes extremely difficult to anastomose the host blood vessel.

FIG. 4 shows one embodiment of the artificial blood vessel of the present invention.

The material of the artificial blood vessel used in the present invention may be a knitted fabric of polyester fibers, a product made of stretched fibrillated fluororesin, a product made of polyurethane, or a non-woven fabric made of polypropylene, polyethylene, polyvinyl alcohol or the like. Needless to say, these artificial blood vessels may be processed with an antithrombotic material before use.

〔Example〕

An artificial blood vessel made of the segmented polyurethane of FIGS. 1 and 3 was formed. The diameter of the aortic anastomosis side was 9 mm, and the diameter of the coronary artery side was 3 mm. When this was subjected to model aortic-coronary bypass using a goat, it was completely patent even after 3 months. On the other hand, when a bypass was formed in the same manner using a comparative sample made of the same material and having a diameter of 3 mm over the entire length, stenosis occurred in one month and occlusion occurred in two months.

〔The invention's effect〕

 The effects of the present invention are as follows.

(1) Since the part to be anastomosed to the aorta has a large diameter, it is easy to make an anastomosis. As a result, the anastomosis is not distorted, and the trouble caused by the anastomosis with the aorta is drastically reduced.

(2) The anastomosis on the aortic side may be performed only once even in the multi-branch bypass.

(3) Since the anastomotic blood vessel on the aortic side is thick, it will not be blocked.

(4) Since a large diameter of the transplanted blood vessel has a large diameter, it does not cause occlusion or stenosis, and there is little pressure loss during that time, and high blood pressure can be maintained up to the tip of the branch pipe, so that even a narrowed portion does not cause thrombosis.

(5) Since the blood flow velocity increases toward the tip (on the side of the coronary artery) due to the taper effect, stenosis or occlusion due to thrombus does not occur at the anastomosis site of the coronary artery.

(6) The tip of the taper can be cut according to the thickness of the coronary artery to obtain the tip with a desired thickness.

Since the present invention has paved the way for the practical application of an artificial blood vessel for aortic-coronary artery bypass, it has opened the door to save many patients who were inoperable and unable to save lives up to now.

[Brief description of drawings]

In the drawings, FIG. 1 is a diagram showing one example of an aorta-coronary artery bypass bifurcated artificial blood vessel in the present invention, and FIG. 2 is a diagram showing an example of an aorta-coronary artery bypass trifurcated artificial blood vessel in the present invention. FIG. 3 is a diagram showing another example of the trifurcated artificial blood vessel for aorta-coronary artery bypass according to the present invention, FIG.
FIG. 1 is a diagram showing an embodiment of an artificial blood vessel for aorta-coronary artery bypass of the present invention, and FIG. 5 is a diagram showing an embodiment of a conventional saphenous vein aorta-coronary artery bypass graft surgery. In the reference numerals used in the drawings, 1 ... Ascending aorta 2 ... Pulmonary artery 3 ... Left atrium 4,5 ... Left coronary artery 6 ... Right coronary artery 7, 7 '... Stenosis 8 ... Bypass artificial Blood vessels 9, 10 ... Bypass vessels.

Claims (1)

[Claims] 1. A large-diameter portion having an end portion having a diameter of 6 mm to 20 mm and two or more branch pipes having an inner cavity communicating with and branched from the large-diameter portion are integrally formed, and the tip of the branch pipe has a diameter of 1 mm to 4 mm.
A multi-branch artificial blood vessel for coronary artery bypassing, wherein a tapered portion is present between the large diameter portion and the tip of the branch tube so that the diameter becomes mm.