Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Made of synthetic material
Reexamination Certificate
1998-12-31
2001-02-20
Willse, David H. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Made of synthetic material
C623S001540, C623S023570, C427S002310, C427S455000, C604S265000
Reexamination Certificate
active
06190407
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to medical articles having associated antimicrobial metal. Furthermore, the invention relates to new approaches for applying antimicrobial metal to a variety of biocompatible materials.
BACKGROUND OF THE INVENTION
A variety of medical articles are designed particularly for contact with a patient's bodily fluids. The duration of this contact may be relatively short, as is typical with wound dressings, or may be long term, as is typical with prosthetic heart valves implanted into the body of a recipient. Some articles such as catheters can have either short term or relatively long term contact. Other articles typically having relatively short term contact with the patient include, without limitation, burn dressings and contact lenses. Other articles typically having long term contact with a patient include, without limitation, implanted prostheses.
Contact of articles with bodily fluids creates a risk of infection. This risk can be very serious and even life threatening. In addition, considerable costs, and longer or additional hospital stays may result due to infection. For example, infections associated with dressings can increase the seriousness of the injury for burn victims. Also, infection associated with an implanted prosthesis can necessitate replacement of the device.
Infections are a particularly common complication resulting from the use in hospitals of percutaneous devices such as catheters. Infections related to catheter use can result from intracutaneous invasion during catheter insertion or from invasion by way of the exit site during use. Adherence of bacteria to the catheter surface complicates treatment of the infection.
Prostheses, i.e., prosthetic articles, are used to repair or replace damaged or diseased organs, tissues and other structures in humans and animals. Prostheses generally must be biocompatible since they are typically implanted for extended periods of time. Examples of prostheses include, without limitation, prosthetic hearts, prosthetic heart valves, ligament repair materials, vessel repair and replacement materials, stents, and surgical patches. A variety of prostheses may incorporate tissue as at least a component of the prosthesis.
Physicians use a variety of prostheses to correct problems associated with the cardiovascular system, especially the heart. For example, the ability to replace or repair diseased heart valves with prosthetic devices has provided surgeons with a method of treating heart valve deficiencies due to disease and congenital defects. A typical procedure involves removal of the native valve and surgical replacement with a mechanical or bioprosthetic valve. Another technique uses an annuloplasty ring to provide structural support to the natural annulus of the native valve.
Prosthetic Valve Endocarditis (PVE) is an infection that can be associated with a heart valve prosthesis. Bacteria can form colonies at the surgical site associated with the implant and in the fabric of the sewing cuff of the valve prosthesis. The deposition of proteins onto the sewing cuff material also is associated with the attachment of bacteria and other pathogens. For this reason, heart valve recipients are cautioned regarding activities that may introduce bacteria into the bloodstream, such as dental work. For bioprosthetic replacement valves, PVE also is associated with the leaflet portion of the valve as well as the sewing cuff portion of the valve.
PVE can be caused by gram-negative bacteria, gram-positive bacteria, fungi or yeast. PVE caused by gram-positive bacteria is particularly prevalent. Diagnosis is based generally on two positive blood cultures for the same organism along with compatible clinical symptoms. Certain organisms are difficult to culture, however, which can complicate diagnosis.
With respect to replacement heart valves, care must be taken to ensure sterility during production and to prevent contamination during the replacement valve implantation process. For example, to ensure sterility or to reduce perioperative contamination, some surgeons apply antibiotics to the prosthesis prior to implantation. These techniques, however, have relatively short-term effectiveness. In spite of these efforts, PVE occurs in about 2 percent to 6 percent of patients.
Typically, infections occurring within the first 60 days after valve replacement are termed early onset PVE while infections occurring more than 60 days after valve implantation are termed late onset PVE. Mortality rates for early onset PVE may range from 30 percent to 80 percent. Mortality rates for late onset PVE can be greater than 20 percent. These high mortality rates emphasize the seriousness of these infections. Similar infections are associated with other prostheses.
SUMMARY OF THE INVENTION
In a first aspect the invention pertains to a method for preparing a medical article comprising biocompatible material, the method comprising:
combining a metal composition and the biocompatible material in a solution under reducing conditions, where the reducing conditions induce a reaction that results in deposition of antimicrobial metal in association with the biocompatible material.
In another aspect, the invention pertains to a method for preparing a medical article comprising biocompatible material, the method comprising:
combining a chemical reducing agent, a metal composition and the biocompatible material in a solution, where the chemical reducing agent induces a reaction that results in the deposition of antimicrobial metal in association with the biocompatible material.
In a further aspect, the invention pertains to a method for preparing a medical article, the method comprising:
illuminating a solution comprising an antimicrobial metal composition, the solution being in contact with biocompatible material, where the illumination results in the deposition of elemental antimicrobial metal, the antimicrobial metal being associated with the biocompatible material.
In addition, the invention pertains to a method for forming a medical article including a biocompatible material associated with an antimicrobial elemental metal, the method comprising:
electroplating an antimicrobial elemental metal onto the biocompatible material.
Furthermore, the invention pertains to a medical article comprising:
a material associated with an antimicrobial elemental metal, the material being selected from the group consisting of polymers and ceramics.
In another aspect, the invention pertains to a method of producing a medical article, the method comprising physically associating antimicrobial metal with another material in the formation of a biocompatible material. The physical association can be performed by forming, such as by weaving or knitting, thread, yarn or fibers into a fabric. Alternatively, the physical association can be performed by associating a metal leaf onto a biocompatible material. The fabric can comprise silver wire in some embodiments. In some embodiments, the physical association is performed by combining an antimicrobial metal composition with a polymer.
Moreover, the invention pertains to a medical article comprising fabric, the fabric comprising threads, fibers or yarns associated with a first antimicrobial metal and threads, fibers or yarns associated with a second elemental metal interspersed with the threads, fibers or yarns associated with the first antimicrobial elemental metal, where the second elemental metal alters the dissociation rate of the antimicrobial elemental metal when the fabric contacts an aqueous solution.
Furthermore, the invention pertains to a method for forming a medical article, the method comprising:
incorporating a fabric into the medical device, the fabric including thread, yarn, filaments or fibers having an associated antimicrobial elemental metal.
The invention also pertains to a medical article including fabric with associated antimicrobial elemental metal, the fabric having physical alterations to increase the surface area of the antimicrobial elemental metal.
In another aspect, the invent
Bergman Darrin J.
Finucane Hallie A.
Guzik Donald S.
Holmberg William R.
Mirsch, II M. William
Dardi Peter S.
Finucane, Esq. Hallie A.
Koh Choon P.
St. Jude Medical Inc.
Westman Champlin & Kelly P.A.
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