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| Resin systems for high energy electron curable resin coated webs |
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| Resin systems for high energy electron curable resin coated webs |
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| Plural layered coated abrasive |
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Atherectomy catheter and method
| Details |
Inventors: Conley, Daniel J.; Deem, Mark E.; Dell, Kent D.; Andreas, Bernard H.;
Assignee: Device for Vascular Intervention, Inc. (Santa Clara, CA)
Primary Examiner: Thaler; Michael H.
Assistant Examiner:
Attorney, Agent or Firm: Townsend and Townsend and Crew
An improved atherectomy catheter and methods of making and using a catheter are disclosed. In one embodiment, the catheter comprises a housing shaft having a torsionally-reinforced outer layer concentrically disposed over a polymeric inner layer, with an inflation tube disposed concentrically over the housing shaft to define an annular inflation lumen. A housing is attached to the distal end of the housing shaft, and may contain an interventional device such as a cutting blade. Apparatus for urging the housing against a vessel wall, such as a balloon, is attached to the housing opposite the an interventional device and is in communication with the inflation lumen. A drive shaft may be rotatably disposed through a longitudinal lumen in the housing shaft, the drive shaft being coupled at its distal end to the interventional device. The method of the invention facilitates construction of a catheter shaft through the steps of forming a flexible tubular polymeric outer layer with a first melting point over a tubular polymeric inner layer with a second melting point, the first melting point being lower than the second melting point; heating the outer layer to at least the first melting point and less than the second melting point, and impregnating a wire braid into the outer layer up to the inner layer. In a preferred embodiment, the inner layer is a fluorocarbon polymer, and the outer layer is a thermoplastic elastomer which is stable near body temperatures, impregnated with one or more layers of a stainless steel wire braid. |
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DETAILED DESCRIPTION In a first aspect of the present invention, a catheter comprises a housing shaft having a proximal end, a distal end and a lumen therebetween.
The shaft includes a torsionally reinforced polymeric outer layer over an unreinforced polymeric inner layer.
An inflation tube is disposed over the housing shaft to define an annular inflation lumen between the inflation tube and the housing shaft.
A housing is attached to the distal end of the housing shaft, and interventional means are disposed on a first side of the housing.
Means for urging the housing toward the vessel wall, which may comprise an inflatable balloon, is attached to a second side of the housing and is in communication with the inflation lumen.
Usually, the interventional means will comprise means for severing tissue, such as a cylindrical, helical, or other rotatable cutting blade.
The interventional means will be rotatably positionable, and engagement of the means with stenotic tissue is achieved by activating the urging means attached to the opposing side of the housing.
Catheters of the present invention thus have a simplified construction, and are manufacturable at relatively low cost.
Moreover, through the use of a torsionally reinforced polymeric outer layer over an unreinforced polymeric inner layer, the housing shaft provides the torsional rigidity desirable for improved rotational positioning of the distal end of the catheter by exerting torque on the proximal end.
Through similar construction, the inflation tube is made very durable.
In a preferred embodiment, the inner layer of the housing shaft will comprise a polymer having a first melting point, and the outer layer of the housing shaft will comprise a polymer having a second melting point, the second melting point being lower than the first melting point.
The outer layer may thus be heated to its melting point, without melting the inner layer.
At such a temperature, the outer layer may be impregnated with reinforcement material, such as a wire braid
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Liquid Purification 
