Dimensionally stable balloons

Abstract

A medical balloon composed of a micro-composite material which provides for radial expansion of a balloon to a predetermined extent, but which has minimal longitudinal growth during balloon inflation. The micro-composite material includes a fibril component, a matrix component, and optionally, a compatibilizer. The fibril component may preferably be liquid crystal polymer fibers randomly scattered through out the balloon material. The liquid crystal polymers are created by extrusion at high speed. An alternative fibril component may be a PET fibers which are uniformly spaced about the balloon material and extend through out the length of the balloon material tube.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of copending U.S. patent application Ser. No. 09 / 426384.BACKGROUND OF THE INVENTION [0002] Medical catheters having a balloon mounted thereon are useful in a variety of medical procedures. A balloon may be used to widen a vessel into which the catheter is inserted by dilating the blocked vessel, such as in an angioplasty procedure. More significant to the present invention however, is the use of a catheter to deliver a medical device, such as a stent, into a body lumen. Some examples of stent delivery balloons are disclosed in U.S. Pat. No. 5,702,418, and U.S. Pat. No. 5,797,877, the entire contents of both patents is hereby incorporated by reference. In these and other medical device delivery applications, radial expansion of a balloon may be used to expand or inflate a stent at a desired positioned within the body. Using a balloon equipped catheter to deliver a stent requires precise position...

AI Technical Summary

Benefits of technology

[0006] The present invention is directed generally to medical balloons which expand only to a predetermined extent, and which have minimal longitudinal and / or minimal radial growth during expansion. Specifically, the invention is directed to a stent delivery balloon composed of a micro-composite material which includes a longitudinal fibril structure that is either parallel to the longitudinal axis of the balloon structure, or that is diagonal to the longitudinal axis at the molecular level of the balloon. The orientation of the fibril structure can limit longitudinal expansion of the balloon and allow the balloon to expand radially as desired, but minimally, or not at all in the longitudinal direction if the fibrils are parallel to the balloon axis, or when the fibrils are oriented diagonally about the axis, can limit both longitudinal and radial expansion of the balloon when inflated.

Problems solved by technology

A known drawback of many previous delivery catheters and balloons is that when a balloon is radially inflated to a desired extent, the balloon will also expand longitudinally.

As a result of longitudinal expansion of a balloon during the delivery of a medical device, the balloon itself, the medical device mounted thereupon or both apparatuses may be shifted from their pre-inflation position resulting in improper delivery of the medical device.

In addition to potentially mis-delivering the medical device as described above, the resulting extended balloon may cause the edges of the stent to push against the vessel wall to a greater extent than they would from radial expansion alone.

The protruding stent edges may damage or tear the surrounding vessel resulting:in potentially serious trauma for the patient.

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