JPH04336077A - Blood vessel expanding member - Google Patents

Abstract

PURPOSE:To expand a blood vessel unit its desired internal diameter is obtained and to hold this expanded internal diameter by forming the blood vessel in a helical coil shape almost closely wound by a wire rod of circular or rectangular cross section of shape memory material, subjected to composition of components so as to obtain its initially set shape at a specific temperature, and applying a plating process to its surface by a metallic material having bioaffinity. CONSTITUTION:A helical coil of external diameter D is formed by almost close winding with a wire rod 2 of shape memory alloy or polymer shape memory material, subjected to composition of components so as to obtain the initially set shape at a 35 to 37 deg.C temperature, and applying a plating process to the outside of the coil by a material prevented from being damaged by blood and provided with affinity also to the tissue of a blood vessel. A blood vessel expanding member, is extended at first and after a small external diameter (d) suited for insertion-advancing in the blood vessel is formed it is mount to the point end of a hollow guide pipe 3, but the blood vessel expanding member is locked between both locking expanded parts 3A, 3B of the hollow guide pipe 3 and carried into the blood vessel. After reaching the target location, pressurized salt water is discharged from the inside of locking expanded parts 3A, 3B and the guide pipe 3 is contracted to be pulled out.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood vessel dilator, and more particularly to a blood vessel dilator for coronary arteries that can also be used for implantation.

0002

[Prior Art] Heart diseases, commonly referred to as myocardial infarction or angina pectoris, occur when the inside of a coronary artery is partially occluded, making it difficult for blood to pass through. The technique is widely practiced. This involves attaching a rotary cutting cutter or a laser heating element to the tip of a thin conduit called a catheter, passing it through the blood vessel to the target site, where the diseased tissue on the inner wall of the blood vessel is removed by cutting, or burned and melted, and the removed material is removed. This is a method of storing it in an attached collection container and pulling it up. Because this method requires a fairly high level of skill, a vasodilatation technique called balloon dilation is more widely used for patients with milder conditions.

[0003] As shown in FIG. 3, this balloon type catheter is called a balloon type catheter, and a balloon, that is, a balloon-like expandable body 102 is attached to the tip of a thin hollow conduit 101 usually made of polyethylene, which is passed into the blood vessel. Expansion body 10
2 reaches the target site of the stenotic lesion portion 1A as shown in FIG. 4(a), the pump 103 pumps physiological saline to inflate the expansion body 102 as shown in FIG. 4(b). The pressure (normally 4 to 5 atmospheres, which can be measured with a pressure gauge at hand) presses the stenotic lesion part 1A in the blood vessel 1 against the inner wall of the blood vessel 1, as shown in Figure (c). This is a method of crushing and shrinking.

[0004] Balloon vasodilation is often used because it is relatively simple and safe; however, the above-mentioned dilatation procedures, including this method, can cause acute thrombosis in the injured part of the vascular intima or due to intimal cell proliferation. The problem of restenosis remains. In order to prevent this, an appropriate expanded state maintaining member having a substantially hollow cylinder shape is fitted inside the blood vessel that has been expanded. An example of this is the hollow cylindrical net-like thing shown by reference numeral 104 in FIG. ((a) in the same figure) After that, it is left in that position to maintain the dilated state of the blood vessel and to help prevent restenosis.

[0005]

[Problems to be Solved by the Invention] However, in general, considering the role of the expanded state holding member, it is natural that the expanded state maintaining member has sufficient flexibility and biocompatibility for transport within the blood vessel, and furthermore, It cannot have a large outer diameter, and it must have the elasticity to be able to expand simultaneously when the expandable body 102 is expanded, and it must also remain fixed at the desired outer diameter even after the expandable body 102 is decompressed. There are various conditions that must be met, such as: The conventional expanded state holding member 104 is insufficient in that this most important holding outer diameter is not large enough.
Moreover, due to the gap 105 between the meshes, there is a problem of restenosis due to proliferation of intima and smooth muscle cells using this gap as a scaffold.

[0006]

[Means for Solving the Problems] This invention has been made to solve the above-mentioned problems.
It is formed into a nearly tightly wound helical coil shape by a wire rod with a circular or rectangular cross section made of a shape memory material whose components are blended to assume the initial set shape at a temperature of °C, and the surface is made of an appropriate metal material with biocompatibility. This is a blood vessel expansion member that has been plated.

[0007]

[Effect] Depending on the patient's body temperature after surgery, this vasodilator will take the shape of a helical coil with the initially set outer diameter according to the properties of the shape memory material, so the initially set outer diameter will be adjusted to the desired inner diameter of the blood vessel to be inserted and treated. If they are aligned, the blood vessel can be expanded to a desired inner diameter and the expanded inner diameter can be maintained by simply placing the blood vessel expansion member on the target blood vessel site.

[0008] Furthermore, since this blood vessel dilation member has a substantially tightly wound spiral coil shape, the inner wall portion of the diseased blood vessel is covered by the outer wall portion of this blood vessel dilation member and comes into direct contact with the plated surface of the metal material. Therefore, it suppresses the proliferation of endometrial cells.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 and 2. Shape memory alloy or polymer whose ingredients are blended so that it assumes the initial set shape at a temperature of 35 to 37 ° C.
Generally speaking, a helical coil with an outer diameter D is formed by almost tightly wound wire rods 2 made of shape memory material, as shown in FIG. Plating is performed using a material that is compatible with tissues. This outer diameter D is determined medically depending on the individual patient and the type of blood vessel to be inserted, but in the case of a coronary artery, it is approximately 2 to 4 mm.

[0010] In order to insert this vasodilator into a blood vessel, the vasodilator is first stretched to increase the pitch so that its outer diameter becomes a small value d suitable for the progress of insertion into the blood vessel. Then, attach it to the tip of the hollow conduit 3. This conduit 3 is a thin hollow tube made of synthetic resin material such as polyethylene, similar to those currently used in balloon catheters, and has a locking bulge with a slightly thinner wall at the tip to make it easier to inflate. 3A, a similar locking bulge 3B is formed at a position closer to the hand by the stretched length when inserting the blood vessel dilation member from the locking bulge 3A, and the vasodilation member is connected to both of the locking bulges 3A, 3B and transported into the blood vessel, and after reaching the target site, the pressurized saline is discharged from these latching enlarged portions 3A and 3B and contracted to form the conduit 2.
All you have to do is pull it out. In addition, in order to pass through a narrowed part, the outer diameter of the locking enlarged part 3A is preferably made as small as possible.

[0011]

[Effects of the Invention] According to the present invention, the vasodilator member changes to the shape of a helical coil with the initially set outer diameter according to the properties of the shape memory material due to the body temperature of the patient after vasodilation. If it is matched to the desired enlarged inner diameter of the blood vessel to be inserted and treated, just by placing this blood vessel expansion member on the target blood vessel site, the blood vessel will be expanded to the desired inner diameter without the need for pump operation, and the enlarged blood vessel will be expanded to the desired inner diameter. It has the advantage that the inner diameter can be maintained. Furthermore, since the vasodilator member of the present invention has a substantially tightly wound spiral coil shape,
Since the diseased inner wall portion of the blood vessel is covered by the outer wall portion of the blood vessel expansion member and comes into direct contact with the metal material, there is an advantage that the risk of proliferation of intimal cells and restenosis is drastically reduced.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a side cross-sectional view showing the vasodilator member of FIG. 1 in an expanded state for insertion.

FIG. 3 is a side view showing a balloon catheter.

FIG. 4 is a side sectional view illustrating a process in which a balloon crushes stenotic tissue within a blood vessel.

FIG. 5 is a side view illustrating a conventional intravascular implant member.

[Explanation of symbols]

1 Blood vessels 2 Shape memory material wire rod

Claims (1)

[Claims] 1. Formed into a substantially tightly wound helical coil shape by a wire rod (2) having a circular or rectangular cross section made of a shape memory material whose components are blended so as to assume an initial set shape at a temperature of approximately 35 to 37°C; A blood vessel dilation member whose surface is plated with an appropriate biocompatible metal material.