Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
1991-05-24
2004-11-23
O'Connor, Cary E. (Department: 3732)
Surgery
Instruments
Internal pressure applicator
C604S160000
Reexamination Certificate
active
06821287
ABSTRACT:
This invention relates to vascular catheters (such as angioplasty catheters) specially adapted for rapid exchange of both the guidewire and the catheter during use. It also relates to the method of using those catheters.
Percutaneous transluminal coronary angioplasty (PTCA) has emerged as the major viable present alternative to bypass surgery for revascularization of stenotic and occluded coronary arteries. Although transluminal angioplasty has application in peripheral artery disease, it is most widely used in the treatment of coronary artery disease. Unlike bypass surgery, percutaneous angioplasty does not require general anesthesia, cutting of the chest wall, extracorporeal perfusion, or transfusion of blood. Percutaneous coronary angioplasty is not only less invasive and less traumatic to the patient, it is also less expensive because the angioplasty patient will have a shorter hospital stay and shorter post-procedure recovery time.
Percutaneous transluminal angioplasty is performed by making a skin puncture with a specially-designed needle in one of the groins, and then introducing a guiding catheter (typically 8 or 9 French size) into the aorta and coronary artery orifice. A smaller caliber catheter which has a built-in inflatable and deflatable balloon of predetermined size and diameter is passed through the guiding catheter which is positioned in the opening of a target artery. This balloon catheter (with the balloon totally deflated by negative pressure) is advanced inside the target artery toward the point of obstruction that needs to be dilated. The guidewire plays an essential role in leading the balloon catheter to the target coronary artery in safety and non-traumatic fashion. With the balloon portion of the catheter properly positioned inside the obstructed segment of the artery, under X-ray fluoroscopic observation, the balloon is inflated by injecting contrast media mixed with saline at a pressure sufficient to overcome the resistance of the arteriosclerotic plaque of the obstructed segment.
By inflating the balloon in the stenosis multiple times over a period of between 10-30 seconds and one or two minutes (allowing blood flow between inflations), the desired dilation of the obstructed segment of the artery can be achieved. When the desired results have been obtained by balloon inflations, the guiding catheter, the balloon catheter (with the balloon completely deflated with negative pressure) and the guidewire are withdrawn from the artery and the patient and the procedure is successfully terminated.
The size and diameter of the balloon to be used in a transluminal angioplasty should be approximately matched to the size and native diameter of the obstructed segment of the artery to be dilated. If the balloon size and diameter is smaller than the native artery, the results of balloon angioplasty are suboptimal, requiring a second dilation with a larger-sized balloon, and if balloon size is too large for the native artery, complications may occur due to arterial wall damage.
During the angioplasty procedure, a guidewire is first advanced into the desired location, after which the angioplasty catheter is advanced over the guidewire. It is sometimes necessary to replace (or exchange) either the guidewire or the balloon catheter during the procedure.
If the balloon is undersized, for example, the catheter must be withdrawn and replaced with a larger balloon catheter in order to permit adequate dilatation of the lesion. With conventional over-the-wire catheters, in which the guidewire lumen extends the entire length of the catheter shaft, a guidewire extension (e.g., 145 cm long) must first be attached to the regular guidewire (e.g. 175 cm long) being used outside the patient before the catheter is withdrawn. This permits the distal end of guidewire to be held in position while the catheter is removed and a new catheter is exchanged. Usually, two to three operators are needed to effect such a catheter exchange.
The catheter disclosed in U.S. Pat. No. 4,762,129 avoids the necessity for extending the guidewire or exchange guidewire (e.g. 300 cm in length) by having a short guidewire lumen that extends substantially only through the distal end of the catheter. This type of catheter is referred to herein as a rapid-exchange catheter. Thus, the guidewire is outside the catheter shaft for much of the catheter length, and is inside the catheter at only the distal end. The catheter can be exchanged without extending the 175 cm regular guidewire, and the exchange can be effected by one or two operators. However, this catheter has a serious drawback of not being able to permit ready exchange of guidewires. In clinical practice, the need for guidewire exchange is more common.
Conventional over-the-wire angioplasty catheters, with a guidewire lumen extending their entire length, permit simple guidewire exchange. During angioplasty procedures, the guidewire tip may become damaged, may be needed of a different type of guidewire or may need to be reshaped to complement the patient's vasculature. The guidewire exchange procedure is readily accomplished with such a conventional over-the-wire catheter. However, with the rapid-exchange type catheter of U.S. Pat. No. 4,762,129, guidewire exchange requires complete removal and reinsertion of both the guidewire and the angioplasty catheter; thus, defeating the original goal of expedient advantage of the rapid-exchange catheter.
Another disadvantage of the rapid-exchange catheter is backbleeding. While the guidewire is being manipulated to select the target vessel or to cross the culprit lesion, the Tuehy-Borst adapter must be loosened. This, in turn, permits backbleeding to occur.
Accordingly, there is a need for an angioplasty catheter that permits rapid-exchange of the catheter like a monorail system, and easy exchange of the guidewire like the conventional over-the-wire system. There is also a need for a catheter that will permit the user to select the mode of usage between the rapid-exchange and the over-the-wire systems.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided an angioplasty catheter comprising a catheter shaft having a proximal end and a distal end, an angioplasty balloon attached to the shaft at the distal end, a balloon inflation lumen extending through the shaft and communicating with the interior of the balloon, and a guidewire lumen extending through the shaft and through the balloon for receiving a steerable guidewire, wherein the guidewire lumen has a proximal opening at the proximal end of the shaft for insertion of a guidewire into the lumen, and a side port for insertion of a guidewire into the lumen through the side wall of the catheter shaft, the side port located distally of the proximal opening, the side port comprising guidewire directing means for permitting a guidewire to extend through the side port distally into the guidewire lumen and exit through the distal opening at the balloon catheter tip; while preventing a guidewire from extending through the side port proximally in retrograde fashion into the guidewire lumen. In one embodiment, the side port is located adjacent to and proximally of the balloon. In another, the side port is located proximally of the balloon within about 35 cm of the balloon. In another variation of this catheter, the side port has proximal and distal ends, and the distal end of the side port is defined by a cut into the guidewire lumen extending generally transversely with respect to the length of the catheter shaft. Preferably, the proximal end of the side port is a cut tapering proximally and outwardly from the distal end of the side port. In another variation of the foregoing catheter, the proximal end of the side port is a cut extending through the guidewire lumen extending proximally from the distal end of the side port. In a preferred embodiment, the guidewire lumen has an outside wall and the guidewire directing means comprises a guide flap having a proximal end and a distal end, the guide flap attached at its proxim
Advanced Cardiovascular Systems Inc.
McAndrews Held & Malloy Ltd.
O'Connor Cary E.
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