Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-07-12
2003-01-28
Denion, Thomas (Department: 3748)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S523000, C604S524000, C604S525000, C604S526000, C604S527000, C264S463000
Reexamination Certificate
active
06511462
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-202607, filed Jul. 16, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a catheter inserted into, for example, a blood vessel for use and a method of manufacturing the catheter.
In general, in performing a selective angiography or angioplasty, used are, for example, an angiography catheter, a guiding catheter, a dilatation catheter and an embolotherapy catheter (microcatheter).
Such a catheter is required to exhibit an excellent operability to permit the catheter to be inserted promptly and with an ensured selectivity into vasculature of a fine complex pattern.
The catheter is also required to have an outer diameter as small as possible while ensuring a predetermined inner diameter in order to widen the range of selection in the insertion region, to alleviate strain given to the patient, and to improve the operability in inserting the catheter into, for example, a blood vessel.
The catheter is required to meet various operability including, for example, pushing capability (pushability) that the pushing force of the operator for moving forward the catheter within a blood vessel can be transmitted from the proximal end of the catheter to the distal end; torque transmitting capability (trackability) that the turning force applied to the proximal end of the catheter can be transmitted to the distal end without fail; the following capability that the catheter is capable of following smoothly and without fail the guide wire preceding the catheter within a curved blood vessel; and kink resistance that, even after the guide wire is withdrawn after the distal end of the catheter has reached a desired region, the catheter is not kinked in the curved portion of the blood vessel. The catheter is also required to exhibit safety that the distal end of the catheter does not damage the inner wall of the blood vessel.
In order to obtain a good pushability and a good torque transmitting capability, it is desirable for the catheter to be formed of a relatively hard material except the distal end portion. In order to obtain a good following capability and safety, it is desirable for the distal end portion of the catheter to be formed of a relatively soft material.
As a catheter meeting the above-noted requirements, a catheter prepared by joining unit tubes made of different materials disclosed in, for example, U.S. Pat. No. 5,792,124, and a catheter prepared by co-extruding a plurality of different kinds of resins, disclosed in, for example, U.S. Pat. No. 5,456,674, are known.
However, the catheter prepared by joining unit tubes made of different materials is likely to be cut away because of decrease in the bonding strength at the joining portion. To overcome this difficulty, it is necessary to increase the thickness of the tube, i.e., the difference between the inner and outer diameters of the tube, making it difficult to diminish the outer diameter of the tube. Also, stepped portions are formed on the outer surface in the joining portions, with the result that the inner wall of the blood vessel tends to be damaged when the catheter is inserted into the blood vessel. In addition, since the rigidity is rapidly changed in the joining portion, the catheter tends to be kinked at the joining portion. In other words, the catheter is not satisfactory in the kink resistance.
On the other hand, a costly manufacturing apparatus is required in the method of manufacturing a catheter by the co-extrusion of a plurality of different kinds of resins, making the method impractical.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a catheter excellent in operability such as the pushability, the torque transmitting capability, the following capability and the kink resistance and a method of manufacturing the catheter that is advantageous in making the catheter small in its outer diameter.
According to a first aspect of the present invention, there is provided a method of manufacturing a catheter having a proximal end, a distal end and a tubular member defining an inner lumen extending between the proximal end and the distal end, the method comprising steps of: preparing a first linear member made of a first resin material and a second linear member made of a second resin material; disposing the first linear member in a dense spiral or mesh in a first region of the tubular member and in a sparse spiral or mesh in a second region of the tubular member; and disposing the second linear member in a sparse spiral or mesh in the first region of the tubular member and in a dense spiral or mesh in the second region of the tubular member.
The method of the present invention may further comprise steps of: disposing the first linear member in an intermediate region between the first and second regions in a spiral or mesh of a disposing density intermediate between the disposing densities in the first and second regions; and disposing the second linear member in an intermediate region between the first and second regions in a spiral or mesh of a disposing density intermediate between the disposing densities in the first and second regions.
In this case, the first region, the intermediate region and the second region are arranged in the order mentioned as viewed from the proximal end of the catheter.
To be more specific, the method of the present invention is performed by, for example, rotating the supply source of the first linear member and the supply source of the second linear member around the tubular member and by adjusting the relative rotating speeds of the supply sources of the first and second linear members so as to adjust the disposing densities of the first and second linear members on the tubular member.
In the method of the present invention, it is desirable for the first linear member to have a flexural rigidity higher than that of the second linear member.
The method of the present invention may further comprise steps of: melting at least partially the first and second linear members disposed on the tubular member so as to mix or fuse the first and second linear members; and solidifying the molten portion.
The method of the present invention may further comprise a step of covering the first and second linear members disposed on the tubular member with a heat shrinkable tube and heating the resultant product, thereby melting at least partially the first and second linear members so as to mix or fuse these first and second linear members and solidifying these first and second linear members.
The method of the present invention may further comprise a step of disposing the first linear member alone in a region on the side of the proximal end relative to the first region of the tubular member.
The method of the present invention may further comprise a step of disposing the second linear member alone in a region on the side of the distal end relative to the second region of the tubular member.
According to a second aspect of the present invention, there is provided a catheter having a proximal end, a distal end and a tubular member defining an inner lumen extending between the proximal end and the distal end, comprising: a first resin layer arranged in a first region of the tubular member and consisting of a first resin material disposed in a dense spiral or mesh and a second resin material disposed in a sparse spiral or mesh; and a second resin layer arranged in a second region of the tubular member and consisting of the second resin material disposed in a dense spiral or mesh and the first resin material disposed in a sparse spiral or mesh.
The catheter of the present invention may further comprise a resin layer arranged in an intermediate region between the first region and the second region of the tubular member and consisting of the first resin material disposed in a spiral or mesh of a disposing density intermediate between the disposing densi
Itou Takenari
Mihara Nobuaki
Burns Doane , Swecker, Mathis LLP
Chang Ching
Denion Thomas
Terumo Kabushiki Kaisha
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