Surgery – Diagnostic testing – Flexible catheter guide
Reexamination Certificate
1991-04-03
2001-04-17
Hindenburg, Max (Department: 3736)
Surgery
Diagnostic testing
Flexible catheter guide
Reexamination Certificate
active
06217526
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to guidewires used in guiding of catheters and to devices and techniques for extending the effective length of the guidewires to facilitate catheter exchanges.
BACKGROUND OF THE INVENTION
In some catheterization techniques, it is desirable to use a series of catheters in order to complete effectively the procedure at hand. For example, in percutaneous transluminal coronary angioplasty procedures in which a balloon catheter is advanced into a stenosed region of the patient's coronary artery and is inflated within the stenosis to dilate the lumen of the artery, it is not uncommon for the physician to require the sequential use of several balloon dilatation catheters having balloons of progressively increasing size. Typically, such catheters are used in connection with a guidewire that extends through the catheter and serves as a guide over which the catheter may be advanced to the stenosis. When performing such a catheter exchange, it is important to do so without shifting and losing the position of the guidewire in the entry so that the guidewire may be used to guide the next catheter to the stenosis. In order to maintain guidewire position, conventional practice has been to use a relatively long exchange wire. The exchange wire, which typically is of the order of 300 cm long (as compared to a conventional guidewire length of the order of 175 cm) is first exchanged for the conventional guidewire by removing the conventional guidewire from the existing catheter and replacing it with the longer exchange wire. Then the existing catheter is withdrawn over the exchange wire, the exchange wire being sufficiently long so that it is never completely covered by the withdrawn catheter thereby enabling the exchange wire to be held in position by the physician or an assistant during the catheter withdrawal. After the initial catheter is removed, the succeeding catheter is advanced over the exchange wire which guides the second catheter to the stenosis. The exchange wire then may be removed and may be replaced with a conventional guidewire which, typically, will be more easily manipulated during the angioplasty procedure.
The foregoing procedures are time consuming and somewhat awkward. A significant advance in the technique for effecting catheter exchanges has been developed and has been in use which involves a system that enables exchange of catheters without using exchange wires. In brief, that system utilizes an extension wire that is attached to the proximal end of the guidewire already in place in the patient. That effectively extends the overall length of the guidewire to that needed for the catheter exchange. The system uses a connection in which the distal end of an extension wire is telescoped together with the proximal end of the guidewire and the junction then is crimped, thus, retaining the wires together by deforming them at their juncture. The crimp is intended to present low resistance to the catheter as it is passed over the connection. Some resistance, however, does result and it has not before been possible to completely eliminate the resistance presented by the crimp. Further inconvenience with the crimped system is that it requires the use of a separate crimping tool. When the guidewire and extension wire are detached, they cannot be reconnected or reused easily because of the deformation formed during their connection. Thus, some inconvenience is presented should it be desirable to make multiple catheter exchanges.
It is among the general objects of the invention to provide an improved connection system for a guidewire and an extension wire.
SUMMARY OF THE INVENTION
In accordance with the present invention, a connection system for a guidewire and guidewire extension utilizes a telescoping connector that is self-latching, disconnectable and reconnectable without deformation of the guidewire or the extension. The connection enables the guidewire extension to be attached for a catheter exchange, then disconnected after the catheter exchange is complete to permit the guidewire and catheter to be manipulated and operated conventionally. Should another catheter exchange be required, the extension wire, which may be reused, is simply reconnected to the proximal end of the guidewire and the catheter exchange procedure may be repeated. The number of guidewire-extension wire connections and disconnections are unlimited as is the number of catheter exchanges that may be performed with the system.
More particularly, the guidewire is provided with a reduced diameter rod that is adapted to mate with a connector socket on the distal end of the extension wire. The extension wire includes a shaft having, on its distal end, a socket adapted to receive and become securely attached to the rod on the proximal end of the guidewire. The connector mounted on the distal end of the wire extension includes a tubular housing attached to the distal end of the extension wire. The tubular housing has an opening at its distal end which receives the wire on the proximal end of the guidewire. A helical coil is contained within the housing and is attached at its proximal end to the proximal end of the housing and distal end of the wire extension shaft. The coil has an outer diameter slightly less than the inner diameter of the housing. The opening at the distal end of the housing is defined by a surrounding inwardly extending lip which is dimensioned to present an obstruction to distal extension of the helical coil within the housing. The inner diameter of the coil is less than the outer diameter of the rod extending from the proximal end of the guidewire. The guidewire and extension wire may be connected simply by inserting the rod at the proximal end of the guidewire into the opening at the end of the housing on the wire extension. The rod is urged into the housing and into the helical coil which causes the helical coil to expand to receive the slightly larger diameter rod. It may be necessary to impart a slight rotation to the wire extension in order to facilitate the extension. Once connected, the attachment is secure and will withstand substantial separation forces without disconnecting. The wire extension and guidewire may be detached simply by rotating the extension wire with respect to the guidewire and while doing so, axially separating the two. The rotation of the helical coil with respect to the rod relaxes the grip of the coil on the rod, thus permitting the two to be separated under a light separation force.
It is among the general objects of the invention to provide an improved guidewire extension system.
A further object of the invention is to provide an improved guidewire extension system which is self-latching and does not require deformation of the joint between the guidewire and guidewire extension.
Another object of the invention is to provide a connection system for a guidewire and guidewire extension which is disconnectable and reconnectable.
Another object of the invention is to provide a guidewire and extension and connection system therefor which minimizes impedance to advancement of a catheter over the joint.
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patent: 2180454 (1987-04-01), None
Hindenburg Max
Medtronic Ave Inc.
Sterne Kessler Goldstein & Fox PLLC
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