CATHETER FOR BLOOD VESSEL

Abstract: This invention relates to a catheter to be inserted into the blood vessel to treat or inspect an affected part in the vessel. To make the insertion easy, this catheter includes an ultra-elastic wire which is disposed inside a catheter body in its longitudinal direction. The ultra-elastic wire may be fixed or disposed removably in an internal passage of the catheter body, or be implanted in part of the catheter body. A water-soluble polymer coating may be applied to the exposed surface of the catheter body or ultra-elastic wire, or a non-X-ray-transmitting material may be applied.

Description: The present invention relates to a catheter for introduction into a blood vessel for the treatment or inspection of a diseased portion within the blood vessel. A catheter for introduction into a blood vessel is used mainly for injection of a medical solution, a contrast media, etc. into the blood vessel for the treatment or inspection of a diseased portion within the blood vessel. The conventional catheter of this type is constructed such that a hub is simply mounted to the proximal end of a flexible tubular body. For introducing the conventional catheter into a blood vessel, a guide wire is inserted in advance into the blood vessel, followed by introducing the catheter into a desired position within the blood vessel along the guide wire. Such a conventional catheter is known from EP-A- 0 141 006. The guide wire thereof is a super-elastic wire, detachably inserted in a lumen of the catheter, and being covered with a synthetic resin layer having an X-ray non transmission material mixed therein. The requirement of guiding by a guide wire necessitates a troublesome operation for a long time for enabling the distal end of the conventional catheter to reach a desired position. Also, a blood vessel after branching is bent and diminished in inner diameter, leading to an increased resistance to the catheter insertion. Naturally, it is difficult to insert a guide wire into the branched blood vessel, making it more difficult to introduce the catheter to reach the desired position. Further, a series of operations for insertion and withdrawal of the catheter give serious pains to the patient. An object of the present invention is to provide a catheter for introduction into a blood vessel, which can be easily introduced even into a branched blood vessel such as a celiac artery without using a guide wire. The catheter of the present invention permits markedly alleviating the pain given to the patient. Also, it is possible to simplify the operation for introducing the catheter into a blood vessel. As claimed, the catheter for introduction into a blood vessel, comprises a catheter body having a lumen opening at a distal end of said catheter and provided at its proximal end with a first hub. A super-elastic wire is detachably inserted in said lumen of the catheter body and is covered with a synthetic resin layer having an X-ray non-transmission material mixed therein. According to the invention, said catheter body is covered on its outer surface with a water-soluble high molecular weight material ; said super-elastic wire leaves a space around said wire for passage of a medical liquid through said lumen ; said wire is attached to a second hub which is detachably fitted in said first hub and has a passage for introducing a medical liquid therethrough, and said super-elastic wire is covered with a water-soluble high molecular weight material covering said synthetic resin layer. According to an embodiment of the invention, said super-elastic wire extends to reach a distal end region of the catheter body, said lumen of the catheter body having a diameter larger than said wire thereby defining said space around said wire, and said passage of said second hub is in communication with said space for introducing said medical liquid through said first and second hubs, said space and out of said opening. Further, the distal portion of the super-elastic wire may be bent to conform with the shape of that portion of a blood vessel at which said distal end portion is to arrive. According to an embodiment of the invention, said second hub comprises a lure tapered portion mounted at the distal end portion of a connector body, the distal end portion of the super-elastic wire being held at the junction between the lure tapered portion and the connector body. The super-elastic wire used in the present invention is formed of an alloy which exhibits an apparent plastic deformation of several % to about 10%, if load is applied to the alloy under temperatures higher than the temperature at which the reverse transformation of the alloy is completed, and which is completely brought back to the original state upon removal of the load. It is most desirable to use a Ti-Ni alloy consisting essentially of 50.5 to 51.0 atomic % of Ni and the balance substantially Ti for forming the super-elastic wire. It is also possible to use a Ti-Ni alloy consisting essentially of 50.3 to 51.0 atomic % of Ni and the balance substantially Ti. Further, it is possible to use a so-called Ti-Ni-X series alloy, where "X" represents at least one kind of a third element. In the catheter of the present invention, the super-elastic wire performs the function performed by a guide wire in the conventional catheter. Thus, the invented catheter can be easily inserted into a branched blood vessel such as a celiac artery without using a guide wire. It follows that the present invention permits simplification of the catheter introducing operation, and also permits alleviating the pain given to the patient. In addition, the time required for the catheter introduction can be shortened to less than about half the time required in the conventional catheter using a guide wire. Fig. 1 is a cross sectional view showing a catheter for introduction into a blood vessel according to one embodiment of the present invention; Fig. 2 is a side view of the catheter for introduction into a blood vessel shown in Fig. 1; Fig. 3 is a cross sectional view along the line III-III shown in Fig. 2; Fig. 4 is a cross sectional view showing in a magnified fashion the hub portion of a catheter according to another embodiment of the present invention; Fig. 5 is a side view showing how to use the catheter shown in Fig. 4; and Figs. 6 and 7 are cross sectional views each showing a catheter for introduction into a blood vessel according to still another embodiment of the present invention. Figs. 1 and 2 collectively show a catheter for introduction into a blood vessel according to one embodiment of the present invention. As seen from the drawings, the catheter comprises a tubular catheter body 1 having an inner diameter of 1.0 mm and a length of 800 mm, a lure tapered hub 2 fixed by fusion, an adhesive or the like to the proximal end of the catheter body 1, and a super-elastic wire 3 having an outer diameter of 0.6 mm and a length of 810 mm. The catheter body 1 is formed of a flexible synthetic resin such as nylon, polyurethane, fluorine resin, or soft fluorine resin. The hub 2 is also formed of a synthetic resin such as nylon. Further, the super-elastic wire 3, which extends through a lumen 1a of the catheter body 1 to reach the distal end region of the catheter body 1, is formed of a Ni-Ti alloy containing at least 50.3 atomic % of Ni. Fig. 3 illustrates as an example how to fix the super-elastic wire 3 within the hub 2. It is seen that the wire 3 is supported by the tip portions of a plurality of projections 2a radially projecting from the inner wall of the hub 2 toward the axis. It is desirable to cover each of the super-elastic wire 3 and the catheter body 1 with an urethane resin layer by the method as described in, for example, Unexamined Published Japanese Patent Application No. 31-45775, so as to modify the surface conditions of these wire 3 and catheter body 1. It is also desirable to cover the outer surfaces of the catheter body 1 and the super-elastic wire 3 with a layer of a water-soluble high molecular weight material such as polyvinyl pyrrolidone, sodium methylvinyl ether maleic anhydride, polyacrylamide hydrolyzate, sodium alginate, sodium polyvinyl sulfonate, ammonium salt of methylvinyl ether maleic anhydride or polyacrylamide quaternary compound. Further, it is also desirable to impart lubricity by wetting with water or an aqueous solution. For example, it is desirable to lightly wipe the surface of the catheter body 1 with gauze immersed in a heparin-added physiological saline so as to achieve lubrication with a water-soluble high molecular weight material. Each of the catheter body 1 and the super-elastic wire 3 is somewhat bent at the distal end portion as shown in the drawings to conform with the shape of the blood vessel into which the catheter is to be introduced. Further, an X-ray intransmissible material may be mixed into the catheter body 1 and the super-elastic wire 3 via the resin coating or the like. In this case, introduction into a blood vessel by utilizing, for example, an X-ray image forming apparatus. For introducing the catheter of the present invention into a blood vessel, it is unnecessary to use a guide wire. Specifically, the catheter is introduced as it is into an artery having an introducing needle, an introducer, etc. retained therein. Under this condition, the hub is operated to transmit torque to the distal end of the catheter so as to achieve selection of passageway at a branched portion of the blood vessel such that the distal end of the catheter reaches a desired position within the blood vessel. Then, a medical solution, an image-forming agent, etc. is injected from the hub 2 into the blood vessel. Figs. 4 and 5 collectively show a catheter according to another embodiment of the present invention. In this embodiment, the super-elastic wire 3 is detachable from the catheter body 1. As seen from Fig. 4, the proximal end of the super-elastic wire 3 is fixed to a hub 4 for fixing the wire 3, and the hub 4 is detachably coupled with the hub 2 of the catheter body 1. The super-elastic wire 3 can be fixed to the hub 4 by a method similar to that shown in Fig. 3. Thus, it is possible to withdraw the super-elastic wire 3 together with the hub 4 after introduction of the catheter body 1 to the desired position within a blood vessel, as shown in Fig. 5. The withdrawal of the wire 3 results in an increased effective area of the lumen 1a of the catheter body, making it possible to increase the injection rate of a medical solution, an image-forming agent, etc. through the hub 2. The other construction is the same as that of the embodiment shown in Figs. 1 to 3 and, thus, the description thereof is omitted. In each of the embodiments described above, the super-elastic wire extends through the lumen of the catheter body. However, the super-elastic wire may be embedded in the material forming the catheter body, as shown in, for example, Fig. 6. It is seen that the super-elastic wire 3 is embedded in the catheter body in a manner to extend in the longitudinal direction of the catheter body 1. Like the embodiment of Fig. 4, the embodiment of Fig. 6 also permits increasing the effective area of the lumen 1a. The other construction of Fig. 6 is the same as that of the embodiment shown in Figs. 1 to 3. Thus, the same reference numeral are put in Fig. 6 to omit the description thereof. Fig. 7 shows a still another modification with respect to the technique of fixing the super-elastic wire. In this case, the connector for fixing the super-elastic wire comprises a lure tapered portion 5 and a connector body 6 having the lure tapered portion 5 mounted at the distal end portion. As seen from the drawing, the distal end portion of the super-elastic wire 3 is held at the junction between the lure tapered portion 5 and the connector body 6 so as to fix the super-elastic wire. The other construction of Fig. 7 is the same as that of the embodiment shown in Figs. 1 to 3. Thus, the same reference numeral are put in Fig. 7 to omit the description thereof. The catheter for introduction into a blood vessel according to the present invention is adapted for use in the treatment or inspection of a diseased portion within a blood vessel, particularly, adapted for injecting or withdrawing a liquid such as a medical solution and a contrast media or, in the case of applying an embolus operation, a thrombolic material such as a gelatine sponge into and out of the diseased portion.

Claims: A catheter for introduction into a blood vessel, comprising a catheter body (1) having a lumen (1a) opening at a distal end of said catheter and provided at its proximal end with a first hub (2), and a super-elastic wire (3), detachably inserted in said lumen (1a) of the catheter body (1) and being covered with a synthetic resin layer having an X-ray non-transmission material mixed therein characterized by the fact that said catheter body (1) is covered on its outer surface with a water-soluble high molecular weight material, by the fact that said super-elastic wire (3) leaves a space around said wire (3) for passage of a medical liquid through said lumen (1a), said wire being attached to a second hub (4 ; 6) which is detachably fitted in said first hub (2) and has a passage for introducing a medical liquid therethrough, and by the fact that said super-elastic wire (3) is covered with a water-soluble high molecular weight material covering said synthetic resin layer. Catheter according to claim 1 wherein said super-elastic wire (3) extends to reach a distal end region of the catheter body (1), said lumen (1a) of the catheter body having a diameter larger than said wire (3) thereby defining said space around said wire (3), and said passage of said second hub (4) being in communication with said space for introducing said medical liquid through said first (2) and second (4) hubs, said space and out of said opening. Catheter according to claim 1 or 2, wherein the distal portion of the super-elastic wire is bent to conform with the shape of that portion of a blood vessel at which said distal end portion is to arrive. Catheter according to any one of the preceding claims, wherein said second hub comprises a lure tapered portion (5) mounted at the distal end portion of a connector body (6), the distal end portion of the super-elastic wire (3) being held at the junction between the lure tapered portion (5) and the connector body (6).

Inventors: ISHIHARA KAZUHITO, KUGO TAKAHIRO, ISHIHARA, KAZUHITO, KUGO, TAKAHIRO
Applicants: TERUMO CORP, TERUMO KABUSHIKI KAISHA
Application year: 1988
Main classification: A61M25
IPC codes: A61M25