Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2002-07-26
2003-09-23
Kennedy, Sharon (Department: 3762)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S103140
Reexamination Certificate
active
06623451
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to devices and methods for use in the manufacture of balloon catheters. More particularly, the present invention pertains to devices which fold a balloon onto a catheter tube during the deflation of the balloon. The present invention particularly, though not exclusively, pertains to springs which can fold the balloon of a dilatation balloon catheter in an uniform and predictable manner during balloon deflation.
BACKGROUND OF THE INVENTION
Arterial blockages caused by the build up of plaque in the arteries of a patient can have grave consequences. Specifically, the build up of plaque in arteries can reduce and eventually block blood flow through the affected vessel. When blood flow is reduced, the heart muscle is deprived of oxygen, and the patient is prone to suffer angina. In severe cases of artery blockage, the patient can suffer a heart attack.
Many modern surgical techniques have been developed to alleviate the stenoses that are formed when plaque builds up in a patient's arteries. For example, a large number of balloon angioplasty devices exist for relieving arterial stenoses by compression of the stenosis. In several respects, balloon angioplasty devices afford numerous advantages over alternative methods. Foremost among these advantages is that open heart bypass surgery can often be avoided by using angioplasty surgical techniques to relieve stenoses in the arteries that supply blood to the heart. For obvious reasons, it is preferable to avoid open heart surgery when possible because such surgery, as is well known, is invasive and can consequently require significant post-operative recovery time. Accordingly, it is preferable to use relatively simpler angioplasty surgical procedures when such procedures are feasible. Importantly, angioplasty procedures are efficacious in the peripheral arteries as well as in the arteries that supply blood to the heart.
In angioplasty surgery, the balloon of a balloon catheter is initially attached to a catheter tube in a deflated configuration and the catheter tube connects a fluid source in fluid communication with the balloon. The balloon is then positioned at the desired location in the affected artery by advancing the catheter through the artery until the balloon is positioned next to the stenosis that is to be treated. Once the balloon has been properly positioned, fluid is infused into the balloon within the artery. As the balloon expands, it dilates the lumen of the artery and compresses the plaque. Upon being compressed, the plaque may break up or flatten out against the arterial wall. The balloon is then subsequently deflated and, once in its deflated configuration, it is either withdrawn from the artery or placed across another stenosis, to restore normal blood flow through the artery.
A particular problem associated with an angioplasty procedure exists during the deflation stage of the balloon, prior to its removal from the artery. Specifically, it is desirable that the balloon be deflated as tightly as practicable to facilitate its removal from the arterial passageways. In any case, the key to removing the balloon catheter with ease is having the balloon collapse evenly and compactly during balloon deflation. Once deflated, the balloon catheter must often travel through tortuous passageways and it is, therefore, important for the balloon to deflate uniformly into a predictable configuration. If the balloon fails to deflate in an uniform manner, an irregular bulge in the balloon may cause difficulties in withdrawing the balloon catheter from the artery.
Various techniques and balloon constructions have been developed to encourage the balloon to deflate in an uniform manner. For example, U.S. Pat. No. 5,350,361 which issued to Tsukashima et al. for an invention entitled “Tri-fold Balloon For Dilatation Catheter and Related Method” discloses a balloon that is constructed with tri-fold flaps. Such flaps are subjected to heat treatment so that when the balloon deflates, the same fold flaps will form allowing the balloon to return to its original deflated configuration. Another example is a balloon catheter with a means to axially twist the inflatable balloon to reduce the diameter of the balloon for passage through the artery. Such a balloon catheter is disclosed in U.S. Pat. No. 4,292,974 which issued to Fogarty et al. for an invention entitled “Dilatation Catheter Apparatus and Method.”
There is, however, a continuing need for improved ways of deflating the balloon of a balloon catheter in a predictable manner for its removal from the artery. The present invention also recognizes the importance of collapsing a balloon evenly onto a catheter tube during balloon deflation so that the balloon catheter can be easily removed from the patient's body without causing damage to the artery. The present invention recognizes the need for an approach that is reliable and predictable. For example, when metals (which have beneficial spring properties) are used to collapse the balloon, several factors must be considered to ensure that the resulting collapsing system is reliable. First, it is important that the metal be corrosion resistant and biocompatible. In this regard, stainless steel is corrosion resistant and has a successful history in invasive medical device applications. Nickel-Titanium alloys such as Nitinol are also suitable for invasive medical device applications.
Another important factor that must be considered when using metals is the strength and reliability of any metal joints that must be made when fabricating a metal article such as a folding spring. In greater detail, the strength and reliability of a metal joint depends on the size and configuration of the joint and the joining method. Thus, when designing a joint to be strong and reliable, it is important to maximize the surface area to be joined and to use a suitable joining method. It is also important that the joining method be easy to use and inexpensive to reduce manufacturing costs. In this regard, the present invention recognizes that soldering and spot welding, when used in conjunction with the proper joint size and configuration, are capable of producing strong reliable joints while minimizing manufacturing costs.
In light of the above, it is an object of the present invention to provide a device and method for manufacturing a device that is useful for folding a balloon predictably and compactly onto a catheter tube during balloon deflation to facilitate removal of the balloon catheter from a patient's body. Another object of the present invention is to provide a device and method for manufacturing a device that is useful for maintaining the balloon tightly wrapped on a balloon catheter when the balloon is in a deflated configuration. It is yet another object of the present invention is to provide a folding spring for a balloon catheter having a strong and reliable metal joint to ensure the reliability of the folding spring. Yet another object of the present invention is to provide a folding spring for a balloon catheter which is relatively simple to manufacture, easy to use, and comparatively cost effective.
SUMMARY OF THE PREFERRED EMBODIMENTS
The present invention is directed to a device and a method for manufacturing a device for folding a balloon of a dilatation balloon catheter during balloon deflation. For the present invention, the device includes a band and a plurality of elongated fingers that are attached to the band.
Each finger in the device of the present invention has a first end and a second end, with the first end being attached to the band and the second end extending away from the band. In their extension, the fingers are substantially parallel to each other and the second end of each finger is rounded. Importantly, the device of the present invention has at least three such fingers. Further, the band of the present invention is formed with a tab and a notch and the length of the band corresponds with the diameter of the catheter tube. When the band is folded, the t
Kennedy Sharon
Nydegger & Associates
Sci-Med Life Systems, Inc.
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