Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-05-26
2001-02-13
Silbaugh, Jan H. (Department: 1732)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S304200, C156S304600, C264S138000, C264S248000, C264S254000
Reexamination Certificate
active
06187130
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to catheters for performing medical procedures. More particularly, the present invention relates to guide catheters for use in an angioplasty procedure.
BACKGROUND OF THE INVENTION
Intravascular diseases are commonly treated by relatively non-invasive techniques such as percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA). These angioplasty techniques typically involve the use of a balloon catheter. In these procedures, a balloon catheter is advanced through the vasculature of a patient such that the balloon is positioned proximate a restriction in a diseased vessel. The balloon is then inflated and the restriction in the vessel is opened.
The most widely used form of angioplasty makes use of a guide catheter positioned within the vascular system of a patient. The guiding catheter assists in transporting the balloon dilation catheter to the restriction in the diseased vessel. During this procedure, the distal end of the guide catheter is typically inserted into the femoral artery located near the groin of the patient. The guide catheter is urged through the vasculature of the patient until its distal end is proximate the restriction. In many cases, the distal end of the guide catheter is positioned in the ostium of the coronary artery. The balloon catheter may then be fed through a lumen in the guide catheter.
The guide catheter must possess a level of rigidity which will allow it to be passed through the vascular system without folding or buckling. Because the guide catheter possesses this level of rigidity, it is desirable to incorporate an atraumatic tip on the distal end of the guide catheter to avoid injury to the walls of the blood vessels.
SUMMARY OF THE INVENTION
The present invention relates generally to catheters for performing medical procedures. More particularly, the present invention relates to guide catheters for use in an angioplasty procedure. A guide catheter in accordance with the present invention includes an elongate shaft. A hub is preferably affixed to the proximal end of the elongate shaft. In the catheter of the present invention, an atraumatic tip is affixed to the distal end of the elongate shaft.
A method of forming an atraumatic tip in accordance with the present invention typically begins with the step of providing an elongate shaft. A joining portion of generally reduced diameter and desired axial length is formed or included proximate a distal end of the elongate shaft. A variety of manufacturing methods may be used to form the joining portion of the elongate shaft including using a thinner wall extrusion segment, material forming processes and material removal processes.
After the joining portion has been formed or otherwise included on the elongate shaft, the joining portion is inserted into the lumen of a first tubular member. The first tubular member is then positioned so that a proximal end thereof is adjacent and abutting a step in the elongate shaft corresponding to the proximal end of the joining portion of the elongate shaft. The first tubular member preferably has a lumen diameter about equal to the outside diameter of the joining portion of the shaft to be disposed thereon.
A mandrel is positioned so that a portion of the mandrel is disposed inside the lumen of the elongate shaft, and the remainder of the mandrel extends distally from the distal portion of the elongate shaft. The mandrel may then be inserted into the lumen of a second tubular member. The second tubular member is slid completely onto the mandrel so that a proximal end of the second tubular member is proximate and preferably abutting the distal end of the first tubular member and the distal end of the elongate shaft. The second tubular member preferably has a lumen diameter about equal to the mandrel diameter.
The next step in a method in accordance with the present invention is positioning a third tubular member so that it overlays both the first tubular member and the second tubular member. The proximal end of the third tubular member is positioned proximate the step in the elongate shaft corresponding to the proximal end of the joining portion of the elongate shaft. The length of the third tubular member is preferably substantially equal to the combined lengths of the first tubular member and the second tubular member so that the distal end of the third tubular member is generally aligned with the distal end of the second tubular member.
In one method in accordance with the present invention, the distal portion of the elongate shaft is overlaid with a sleeve. The first tubular member, the second tubular member, the third tubular member, and the joining portion of the elongate shaft are all disposed in a lumen of the sleeve. In a presently preferred method, the sleeve is comprised of heat shrink tubing. After placing the sleeve in the desired position, heat is applied to the sleeve causing it to shrink. After shrinking, the diameter of the sleeve lumen is substantially equal to the outer diameter of both the third tubular member and the elongate shaft.
The first tubular member, the second tubular member, the third tubular member, and the distal portion of the elongate shaft are heated to an elevated temperature. A number of methods may be used to heat the assembly including convection, conduction and radiation.
In a presently preferred method in accordance with the present invention, the first tubular member, the second tubular member, and the third tubular member are heated to a temperature at or above their melting point, causing them all to fuse together forming an integral distal tip. The elevated temperature also causes the distal tip to be securely bonded to the distal portion or joining portion of the elongate shaft.
REFERENCES:
Carlson, D. Peter et al., “Fluoropolymers, Organic,”Ullmann's Enclyclopedia of Industrial Chemistry, vol. A 11 (1988) pp. 393-428.
Johnson, R. W., “Paste Extrusion of Filled TFE-Fluorocarbon Resin for Wire Insulations,”SPE Journal, Feb. 1961, pp. 151-154.
Lontz, John F. et al., “Extrusion Properties of Lubricated Resin From Coagulated Dispersion,”Industrial and Engineering Chemistry, vol. 44, No. 8, Aug. 1952, pp. 1805-1810.
McCane, Donald I., “Tetrafluoroethylene Polymers,”Encyclopedia of Polymer Science and Technology, vol. 13 (1970) pp. 623-654.
Benson Thomas Mark
Berard John
Moore Diana
Scheinost Jeff Voy
Crompton Seager & Tufte LLC
Sci-Med Life Systems, Inc.
Silbaugh Jan H.
Staicovici Stefan
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