CA2381815A1 - Radioactive graft or cuff - Google Patents
Radioactive graft or cuff Download PDFInfo
- Publication number
- CA2381815A1 CA2381815A1 CA002381815A CA2381815A CA2381815A1 CA 2381815 A1 CA2381815 A1 CA 2381815A1 CA 002381815 A CA002381815 A CA 002381815A CA 2381815 A CA2381815 A CA 2381815A CA 2381815 A1 CA2381815 A1 CA 2381815A1
- Authority
- CA
- Canada
- Prior art keywords
- radioactive
- graft
- implantable
- particles
- flexible wire
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
- A61F2/06—Blood vessels
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- A61P9/00—Drugs for disorders of the cardiovascular system
- A61P9/08—Vasodilators for multiple indications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2210/00—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
- A61F2210/0095—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof radioactive
Abstract
Radioactive grafts or cuffs are made by incorporating radioactive elements into a pliable material such as ePTFE. The radioactive grafts or cuffs are placed into the body to prevent the proliferation of malignant cells. For example, a graft or cuff may be used in an occluded lumen after it has been opened to prevent subsequent restenosis. While the grafts are used primarily for implantation inside a body lumen, the cuffs can be used in a variety of locations including being wrapped around the outside of an affected vessel. Some embodiments of the present invention incorporate radioactive seeds into ePTFE grafts. The radioisotopes comprising the seeds are chosen according to their radioactive properties and are mixed with the PTFE prior to extrusion. Following extrusion, the PTFE is expanded and sintered to yield a final product.
Description
20-09-2001 2001 17:21 J A KEMP & CO No.08b9 FUS0026111 CVO 01/Z1106 . PCTNSOOl2611X
xAnxo~c~ car oR cv~
' ~ 1_ FieldoftheInvention 1'he present invention xetates generally to the field of medical devices, and more particularly, to devices and, methods to avoid vascular restaaosis.
~ ' ' 2. I2~s~.~ ' M~my devices such as steats have been used by physicians to prevent restenosis of blood vessels following tr~Gats to oxpa~nd vessels nairoovsd by arteriosclerosis:
' Following angioplasty, to correct arteriosclerosis reatmosis often. oconrs because such ' try stimulate excess a prolifetatioa IO Another solution to 'the problem of na:rowed vessels is to surgically bypass them with a prosthesis. Polytetsaftuoroethyleae (PTA has prvvetn adv. as a material from which to fabricate blood vessel grabs ar prostheses. This is partially because PTFE is ex~mely biocampadble causing little or no immuaogenic xeaction when placed within the Zm~nan body: ?his is also because in its prafcrred form, expanded: P,3'FE
.(~''~E)~ ~
~g , material is light and porous and can be readily colonized by living cells-so teat it becomes a p~a~d part of the body. Unforttmately, the process of suturing such a pmstsiesis of a living vessel often stimulates cellular proliferation sim~ar to angioplasty.
The. fas'lure modes of vascular grafts are fi~equently related -to a ~ lum~al hyper-pmliferative cellular response that eveamally affects the flow dy~ics resulting in thrombotic events and occlasion 'vf , .
EmpfangsAMENDED SHEET
xAnxo~c~ car oR cv~
' ~ 1_ FieldoftheInvention 1'he present invention xetates generally to the field of medical devices, and more particularly, to devices and, methods to avoid vascular restaaosis.
~ ' ' 2. I2~s~.~ ' M~my devices such as steats have been used by physicians to prevent restenosis of blood vessels following tr~Gats to oxpa~nd vessels nairoovsd by arteriosclerosis:
' Following angioplasty, to correct arteriosclerosis reatmosis often. oconrs because such ' try stimulate excess a prolifetatioa IO Another solution to 'the problem of na:rowed vessels is to surgically bypass them with a prosthesis. Polytetsaftuoroethyleae (PTA has prvvetn adv. as a material from which to fabricate blood vessel grabs ar prostheses. This is partially because PTFE is ex~mely biocampadble causing little or no immuaogenic xeaction when placed within the Zm~nan body: ?his is also because in its prafcrred form, expanded: P,3'FE
.(~''~E)~ ~
~g , material is light and porous and can be readily colonized by living cells-so teat it becomes a p~a~d part of the body. Unforttmately, the process of suturing such a pmstsiesis of a living vessel often stimulates cellular proliferation sim~ar to angioplasty.
The. fas'lure modes of vascular grafts are fi~equently related -to a ~ lum~al hyper-pmliferative cellular response that eveamally affects the flow dy~ics resulting in thrombotic events and occlasion 'vf , .
EmpfangsAMENDED SHEET
-2-blood flow. Dialysis access grafts typically fail at the venous anastomotic site due to flow related intimal hyperplasia. Peripherally placed bypass grafts often fail due to intimal thickening at the suture sites.
Clinical research has indicated that ionizing radiation is capable of reducing S restenosis and preventing cellular proliferation in vascular applications.
However, the concept of Vascular Brachytherapy is relatively new. Although radiation has been used for years in Oncology, its use for the reduction of smooth muscle cell proliferation and the reduction of restenosis in vascular applications is recent. Ionizing radiation has the ability to damage cellular DNA and can either prevent the cells from dividing or can kill them outright. The utilization of a radiation source in vascular graft, especially if incorporated into ePTFE, may have the ability to maintain graft patency for longer periods of time by preventing the hyper-proliferative responses mentioned above.
A major problem with some current methods of treating restenosis through radiation therapy is that the radiation source is present as a fluid within the vascular lumen, such that the possibility of leakage is present, potentially causing major injury to the patient. For example, U.S. Patent No. 5,616,114 to Thorton et al. discloses an apparatus and method to deliver radiation to the walls of a blood vessel through the use of a catheter with a balloon tip which balloon can be inflated with radioactive liquid. It would be desirable to provide radioactive therapy to areas of the body without the risk of causing injury to the patient in the event of a leak caused by balloon breakage.
2001 17:22 J A KEMP & CO No.O$59 P °''"
20-09-2001 . , . . CA 02381815 2002-02-12 US0026111
Clinical research has indicated that ionizing radiation is capable of reducing S restenosis and preventing cellular proliferation in vascular applications.
However, the concept of Vascular Brachytherapy is relatively new. Although radiation has been used for years in Oncology, its use for the reduction of smooth muscle cell proliferation and the reduction of restenosis in vascular applications is recent. Ionizing radiation has the ability to damage cellular DNA and can either prevent the cells from dividing or can kill them outright. The utilization of a radiation source in vascular graft, especially if incorporated into ePTFE, may have the ability to maintain graft patency for longer periods of time by preventing the hyper-proliferative responses mentioned above.
A major problem with some current methods of treating restenosis through radiation therapy is that the radiation source is present as a fluid within the vascular lumen, such that the possibility of leakage is present, potentially causing major injury to the patient. For example, U.S. Patent No. 5,616,114 to Thorton et al. discloses an apparatus and method to deliver radiation to the walls of a blood vessel through the use of a catheter with a balloon tip which balloon can be inflated with radioactive liquid. It would be desirable to provide radioactive therapy to areas of the body without the risk of causing injury to the patient in the event of a leak caused by balloon breakage.
2001 17:22 J A KEMP & CO No.O$59 P °''"
20-09-2001 . , . . CA 02381815 2002-02-12 US0026111
-3-Other methods of using radiation to treat restenosis extzploy radioactive sources (often metallic) delivered by catheter. A d~fficutty with this approach i9 leaving the catheter in the patient's circulatory system for a long enough time to adequately affect restmaosis. A radioactive source of adequate strength so as to minimize the indwelling time of ttxe catheter may be so strong as to have a potential for overexposure and prove dangerous to work with. A s ounce weak enough to avoid overexposure danger may result in problcxns caused by tb~e lengthy indwelling of the delivery catheter. Yet another alternative is to place the radioactive sources oz~ a metal stem. This approach may cause damage through direct eoutact between the radioactive stmt and the vessel. Also, it may be difficult to achieve the desired pattern of radiation because the pattern is determined by the physical canstrucdon of the stmt.
US-A-5873811 discloses an admixture of polymcrie ac~esive witb~
radioactive particles which was cured aver application to a vessel wall.
SLmrIIVIARY OF ~~N~',LON
The present invention is directed to radioactive grafts or cuffs, wherein radioactive therapy is localized to an afflicted area This can be accomplished in several different ways by incorporating radioactive elements into vascular gza~es ox similar irnplantable medical devices.
It is an object of this invc~auon to provide an i~ao~pla~atable m~sdical~
device this-... .
utilizes radiation therapy to prevent excess tissue proliferation especially proliferation resulting in restenosis of blood vessels. ' It is also an object of tbui5 invention to provido a device for radiation therapy that does not involve the transport of leak-prone radioactive ~,uid ~kbxough the body.
EmDfang:AMENDED SHEET
..._.. .w.r:.~,t"" .
~n co~ 2001 11:22 J A KEMP & CO ~o,OgSg n 20-09-2001 ' - ' ' ~ CA 02381815 2002-02-12 US0026111 ..
These and additional objects are accomplished by a first aspect of the invention as defned in claim 1 and by a second aspect of the invention as defined in claim 4. The radioactivity may be imparted through tbie incozpoxataon of radioactive "seeds", coals, wixes, fluids, etc. eathex epcapsulated, impregnated, wrapped around or otbexwise attached to a vascular graft, patch, drape or other implantable nnedzcal device. The material of constxuctian could be cy'TFE, polyester, silicon, polyurethane ox any athet bxo~xedical material. The design of the device and choice of the radioisotope material dictates the duration and strength of the ra,dioaetivxty.
The biomedical material envelops and encapsulates tbo radioactive souxce preventing accidental release and providing a "spacer" between the source and the cellular tissue to be treated.
The present uavenlaon contemplates five pximary ezzzbadizztents, although one slailled in the art can appreciate a greaser numbs' of possibilities based on the inventive concepts hereiua_ ,A, fast eznbodirn~ent includes incorporating radioactive "seeds" (grains, granules, encapsulated radioactive fluid or other radioactive particles) into a graft eithex alozag ats length ox at proximal and distal ends. Tb~e seeds can be placed into the ePTI?'E or other biomedical material prior to extrusion (e.g., coextruded) or fabrication so that they will be embedded into the graft and ~l havo au even distribution withita the gz~a~'t. ,A. second embodirttcut uses radioactive secd$
implanted in the biomedical matcnial as in the first embodiment, but the end product is in the form of a "bandage" that is wrapped around a synthetic or natural vessel, -axxadiaxing the vessel to inhibit the tissue proliferation. A third embodime~;t incorporates radioactive ware into a graft by coiling~the wane along its length or at isolated positions (e.g, near the point of aoastamosis with the living vasculatuare). Zn the case ofwoven biomedical zaatexials (e.g., polyester) the wire can be cowoven with the Empfanss:AMENDED SHEET
=5-biomedical material. The radioactive "wire" can actually be a beading of solid plastic (e.g., PTFE) which contains radioactive powder or seeds. Such beading can be readily laminated to biomedical graft material. A fourth embodiment includes impregnating radioactive agents into the wall of a graft. Finally, a fifth embodiment utilizes an encapsulated stmt graft with .
pockets that are filled with radioactive material. This embodiment can be used intraluminally or as an interposition graft.
A more complete understanding of the radioactive grafts or cuffs will be afforded to those skilled in the art, as well'as a realization of additional advantages and objects thereof, by a consideration of the following detailed description of the preferred embodiment.
Reference will be made to the appended sheets of drawings which will first be described briefly.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a first embodiment of the present invention with radioactive seeds dispersed throughout a graft;
Fig. 2 is a cut-away view of a second embodiment of the present invention with the radioactive seeds of Fig. 1 dispersed throughout a cuff like device;
Fig. 3 is a perspective view of a third embodiment of the present invention vaith a radioactive coil (wire or beading) wrapped around a graft;
Fig. 4 is a perspective view of a fourth embodiment of the present invention with pockets of radioactive fluid dispersed throughout a graft;
Fig. 5 is a diagrammatic cross-sectional view of a mandrel and die assembly which is used to extrude a graft (especially PTFE) containing radioactive agents.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention satisfies the need for a medical device to prevent restenosis through radioactive elements incorporated therein. This can be accomplished by mixing the radioactive seeds or powders into PTFE or other biomedical material before extrusion of the device so that the radioactive elements are evenly distributed throughout the resulting graft or cuff. Another method of incorporation is to wrap a solid radioactive element (wire or beading) around the device during manufacture or just prior to implanting into the body. It should be appreciated that the various devices can be fabricated with a non-radioactive component that is then rendered radioactive by neutron bombardment prior to use. This allows device manufacture without need to worry about radioactive contamination of the site or workers. Also, neutron bombardment can be used to generate radioactive isotopes with such short half lives that normal manufacture and delivery would be impractical (that is, the radioactivity would be significantly decayed by the time the device was delivered).
Referring now to the drawings, in which like reference numbers represent similar or identical structures throughout, Fig. 1 illustrates a first embodiment of a radioactive graft 10.
The graft 10 is composed of a biomedical material (e.g., ePTFE) 14 with embedded radioactive seeds 12. The seeds 12 (either solid particles or radioactive fluid droplets) are either co-extruded with the material already in a radioactive state, or are treated after _7_ extrusion by neutron bombardment or the like. The latter method of forming the radioactive seeds 12 would present various advantages with respect to manufacturability, safety and shelf life. In the case where the material is PTFE or a similar substance extrusion will be explained with reference to Fig. 5 below.
By implanting the radioactive seeds 12 into the ePTFE covering 14, the use of the radioactive substance becomes wide ranging. The flexibility of the radioactive graft 10 enables it to be used in many applications such as on the inside or outside of a stmt. With the radioactive element in the form of seeds, the radioactive properties can be manipulated based on need. Thus, if a longer duration of treatment is necessary, a long life, low energy isotope can be utilized; conversely, if a shorter more intense treatment is desired, a different isotope can be employed.
Fig. 2 illustrates a second embodiment of the present invention which is akin to the first embodiment. Radioactive cuff 20 includes a strip 24 made of any biomedical material, such as ePTFE that is nonabsorbable, with imbedded radioactive seeds 12. As shown in Fig.
2, the radioactive cuff 20 is wrapped around a body vessel 70 like a bandage, so that the radioactive seeds 12 irradiate the proliferating cells 72 within the vessel.
This cuff 20 is extremely versatile and can be used in many different applications, including treatment of non-vascular malignancies such as those found in the synthetic replacement of a bile duct. In fact, radioactive cuff 20 can be utilized for nearly any tube or lumen in the body that is being occluded by a growth. As with the first embodiment, the radioactive properties of the seeds 12 can be chosen based on the specific application of the device, although an isotope with a _g_ very long half life emitting relatively low energy radiation will normally be preferred. As in all cases of the present invention, the ePTFE prevents direct contact between the vascular tissue and the radioactive source. Thickness of the ePTFE can be selected to provide the ideal spacing between the source and the tissue.
Fig. 3 shows a third embodiment of the present invention. The graft structure includes a graft or tubular member 34 with a radioactive wire 32 coiled radially around the outside surface, extending along its length. Beading as of PTFE containing radioactive material can be used in place of wire. Beading can be readily laminated to the graft as can wire clad in an appropriate plastic material. If the biomedical material is woven or knitted, the wire or beading can also be woven or knitted into the structure. The graft structure 30 can be used in conjunction with a stmt in which the graft structure 30 is used to cover either a luminal or abluminal stent surface for insertion into a body lumen. The radioactive wire 32 would then act to reduce the possibility of restenosis after the stmt was deployed by eliminating the proliferating cells. Most likely the radioactive wire or beading would be limited to the end regions of the graft 34 where it is sutured to the patient's vasculature. The radioactive wire 32 can be attached to the graft with adhesives.
Alternatively, the wire. can be coated with PTFE (e.g., by inserting the wire 32 into an elongate PTFE tube of a slightly greater diameter than the wire 32) or other plastic. This coated wire can then be adhered to the graft 34 through heat and pressure or through the use of an adhesive.
Fig. 4 illustrates a fourth embodiment of the present invention. In this embodiment, the radioactive agent is again incorporated into an ePTFE or other biomedical material .~rN. 1UU1 II:'tt ~ A KEMP & CO No.0869 P~ U/IV
wo oxnx~o6 ~ ~ rcr~soa~zsm .9..
member. Flerc, !he radioactive substance is in the form of a liquid wharein a radioaetrve solutiQ~a is prepared sad small droplets of the solution aro encased by. tu~~
plastic shells. The .rcsulnng radioactive balls 4Z arc co-a~t~ded with the biomedical material, 44; creat~ug a radioactive grad 40 contaiaiag small pockets 46 filled with radioactive balls 42. Beside co-. ~truding techniques, the graft 40 can also be created by implanting or enezpsulating tire t '' radioactive balls 42 after graft fabrication.
In a Bdlh aabodiment; much Iike the first and third cmbodituents, radiosdive or radiophatmaceutieat aarc izupregaated directly into the wall of as ePTFE graft without boing aggregated as "sends". in this case, the radioactive agent can come iri the foes of a IO gnouad up solid or powder which is coextruded with the PT~1~. Whit refexence to the first, third and fifth embodiments, Fig. 5 illustrates a ram extruder assembly 50 for co-acrtuding a billet of material, whirls is this case consists of PTFE mixed wilt: any of the radioactive agents described. The ram extzuder assembly 50 includes as extrusion bxael 52,. an extrnsiau die 54, a mandrel 55, and g ram 58. The billet of material S9 is placed within tho .
I S cxtnuion barrel 5Z. Force is applied to i~a s8 which in tern cxpols pressiu~e on Errs YtiIIet of , . ~aI 59. The gr~ causes the bola of tnataial 59 to be extruded around the mandrel . .. _ 56, through t~ttc ion die 54 so that it issue as a tubular a~ctrud~e 60. An arrow 62 shows tbc direction of the ~ctrarion. The tubular adtudate b0 is then eapaaded and s is acdordaace wig , the atpsas:.on and sinteaag Procedures tmdcrtakea with puss PTFE
ZO vascular grafts which errs well known in the art. 'Where plastic aarased radioactive HqQid ball 4,i are used, earapsulation materials arc selected so that the~exttusion process does not Emvfane; ~, ~~ ~ _ ,~..~
AMENDED SHEET
result in rupture of the balls 42 and release of radioactive liquid.
Having thus described a preferred embodiment of the radioactive graft, it will be apparent to those skilled in the art how certain advantages of the present invention have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of~the present invention. Some examples have been illustrated with ePTFE as a biomedical material, but it should be apparent that the inventive concepts described above would be equally applicable to polyester, organosilicon, polyurethane or any other biomedical material that can be extruded or woven. Moreover, the words used in this specification to describe the invention and its various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification.
Thus, if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself. The definitions of the words or elements of the following claims are, therefore, defined in this specification to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same fimction in substantially the same way to obtain substantially the same result. The described embodiments are to be considered illustrative rather than restrictive. The invention is further defined by the following claims.
US-A-5873811 discloses an admixture of polymcrie ac~esive witb~
radioactive particles which was cured aver application to a vessel wall.
SLmrIIVIARY OF ~~N~',LON
The present invention is directed to radioactive grafts or cuffs, wherein radioactive therapy is localized to an afflicted area This can be accomplished in several different ways by incorporating radioactive elements into vascular gza~es ox similar irnplantable medical devices.
It is an object of this invc~auon to provide an i~ao~pla~atable m~sdical~
device this-... .
utilizes radiation therapy to prevent excess tissue proliferation especially proliferation resulting in restenosis of blood vessels. ' It is also an object of tbui5 invention to provido a device for radiation therapy that does not involve the transport of leak-prone radioactive ~,uid ~kbxough the body.
EmDfang:AMENDED SHEET
..._.. .w.r:.~,t"" .
~n co~ 2001 11:22 J A KEMP & CO ~o,OgSg n 20-09-2001 ' - ' ' ~ CA 02381815 2002-02-12 US0026111 ..
These and additional objects are accomplished by a first aspect of the invention as defned in claim 1 and by a second aspect of the invention as defined in claim 4. The radioactivity may be imparted through tbie incozpoxataon of radioactive "seeds", coals, wixes, fluids, etc. eathex epcapsulated, impregnated, wrapped around or otbexwise attached to a vascular graft, patch, drape or other implantable nnedzcal device. The material of constxuctian could be cy'TFE, polyester, silicon, polyurethane ox any athet bxo~xedical material. The design of the device and choice of the radioisotope material dictates the duration and strength of the ra,dioaetivxty.
The biomedical material envelops and encapsulates tbo radioactive souxce preventing accidental release and providing a "spacer" between the source and the cellular tissue to be treated.
The present uavenlaon contemplates five pximary ezzzbadizztents, although one slailled in the art can appreciate a greaser numbs' of possibilities based on the inventive concepts hereiua_ ,A, fast eznbodirn~ent includes incorporating radioactive "seeds" (grains, granules, encapsulated radioactive fluid or other radioactive particles) into a graft eithex alozag ats length ox at proximal and distal ends. Tb~e seeds can be placed into the ePTI?'E or other biomedical material prior to extrusion (e.g., coextruded) or fabrication so that they will be embedded into the graft and ~l havo au even distribution withita the gz~a~'t. ,A. second embodirttcut uses radioactive secd$
implanted in the biomedical matcnial as in the first embodiment, but the end product is in the form of a "bandage" that is wrapped around a synthetic or natural vessel, -axxadiaxing the vessel to inhibit the tissue proliferation. A third embodime~;t incorporates radioactive ware into a graft by coiling~the wane along its length or at isolated positions (e.g, near the point of aoastamosis with the living vasculatuare). Zn the case ofwoven biomedical zaatexials (e.g., polyester) the wire can be cowoven with the Empfanss:AMENDED SHEET
=5-biomedical material. The radioactive "wire" can actually be a beading of solid plastic (e.g., PTFE) which contains radioactive powder or seeds. Such beading can be readily laminated to biomedical graft material. A fourth embodiment includes impregnating radioactive agents into the wall of a graft. Finally, a fifth embodiment utilizes an encapsulated stmt graft with .
pockets that are filled with radioactive material. This embodiment can be used intraluminally or as an interposition graft.
A more complete understanding of the radioactive grafts or cuffs will be afforded to those skilled in the art, as well'as a realization of additional advantages and objects thereof, by a consideration of the following detailed description of the preferred embodiment.
Reference will be made to the appended sheets of drawings which will first be described briefly.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a first embodiment of the present invention with radioactive seeds dispersed throughout a graft;
Fig. 2 is a cut-away view of a second embodiment of the present invention with the radioactive seeds of Fig. 1 dispersed throughout a cuff like device;
Fig. 3 is a perspective view of a third embodiment of the present invention vaith a radioactive coil (wire or beading) wrapped around a graft;
Fig. 4 is a perspective view of a fourth embodiment of the present invention with pockets of radioactive fluid dispersed throughout a graft;
Fig. 5 is a diagrammatic cross-sectional view of a mandrel and die assembly which is used to extrude a graft (especially PTFE) containing radioactive agents.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention satisfies the need for a medical device to prevent restenosis through radioactive elements incorporated therein. This can be accomplished by mixing the radioactive seeds or powders into PTFE or other biomedical material before extrusion of the device so that the radioactive elements are evenly distributed throughout the resulting graft or cuff. Another method of incorporation is to wrap a solid radioactive element (wire or beading) around the device during manufacture or just prior to implanting into the body. It should be appreciated that the various devices can be fabricated with a non-radioactive component that is then rendered radioactive by neutron bombardment prior to use. This allows device manufacture without need to worry about radioactive contamination of the site or workers. Also, neutron bombardment can be used to generate radioactive isotopes with such short half lives that normal manufacture and delivery would be impractical (that is, the radioactivity would be significantly decayed by the time the device was delivered).
Referring now to the drawings, in which like reference numbers represent similar or identical structures throughout, Fig. 1 illustrates a first embodiment of a radioactive graft 10.
The graft 10 is composed of a biomedical material (e.g., ePTFE) 14 with embedded radioactive seeds 12. The seeds 12 (either solid particles or radioactive fluid droplets) are either co-extruded with the material already in a radioactive state, or are treated after _7_ extrusion by neutron bombardment or the like. The latter method of forming the radioactive seeds 12 would present various advantages with respect to manufacturability, safety and shelf life. In the case where the material is PTFE or a similar substance extrusion will be explained with reference to Fig. 5 below.
By implanting the radioactive seeds 12 into the ePTFE covering 14, the use of the radioactive substance becomes wide ranging. The flexibility of the radioactive graft 10 enables it to be used in many applications such as on the inside or outside of a stmt. With the radioactive element in the form of seeds, the radioactive properties can be manipulated based on need. Thus, if a longer duration of treatment is necessary, a long life, low energy isotope can be utilized; conversely, if a shorter more intense treatment is desired, a different isotope can be employed.
Fig. 2 illustrates a second embodiment of the present invention which is akin to the first embodiment. Radioactive cuff 20 includes a strip 24 made of any biomedical material, such as ePTFE that is nonabsorbable, with imbedded radioactive seeds 12. As shown in Fig.
2, the radioactive cuff 20 is wrapped around a body vessel 70 like a bandage, so that the radioactive seeds 12 irradiate the proliferating cells 72 within the vessel.
This cuff 20 is extremely versatile and can be used in many different applications, including treatment of non-vascular malignancies such as those found in the synthetic replacement of a bile duct. In fact, radioactive cuff 20 can be utilized for nearly any tube or lumen in the body that is being occluded by a growth. As with the first embodiment, the radioactive properties of the seeds 12 can be chosen based on the specific application of the device, although an isotope with a _g_ very long half life emitting relatively low energy radiation will normally be preferred. As in all cases of the present invention, the ePTFE prevents direct contact between the vascular tissue and the radioactive source. Thickness of the ePTFE can be selected to provide the ideal spacing between the source and the tissue.
Fig. 3 shows a third embodiment of the present invention. The graft structure includes a graft or tubular member 34 with a radioactive wire 32 coiled radially around the outside surface, extending along its length. Beading as of PTFE containing radioactive material can be used in place of wire. Beading can be readily laminated to the graft as can wire clad in an appropriate plastic material. If the biomedical material is woven or knitted, the wire or beading can also be woven or knitted into the structure. The graft structure 30 can be used in conjunction with a stmt in which the graft structure 30 is used to cover either a luminal or abluminal stent surface for insertion into a body lumen. The radioactive wire 32 would then act to reduce the possibility of restenosis after the stmt was deployed by eliminating the proliferating cells. Most likely the radioactive wire or beading would be limited to the end regions of the graft 34 where it is sutured to the patient's vasculature. The radioactive wire 32 can be attached to the graft with adhesives.
Alternatively, the wire. can be coated with PTFE (e.g., by inserting the wire 32 into an elongate PTFE tube of a slightly greater diameter than the wire 32) or other plastic. This coated wire can then be adhered to the graft 34 through heat and pressure or through the use of an adhesive.
Fig. 4 illustrates a fourth embodiment of the present invention. In this embodiment, the radioactive agent is again incorporated into an ePTFE or other biomedical material .~rN. 1UU1 II:'tt ~ A KEMP & CO No.0869 P~ U/IV
wo oxnx~o6 ~ ~ rcr~soa~zsm .9..
member. Flerc, !he radioactive substance is in the form of a liquid wharein a radioaetrve solutiQ~a is prepared sad small droplets of the solution aro encased by. tu~~
plastic shells. The .rcsulnng radioactive balls 4Z arc co-a~t~ded with the biomedical material, 44; creat~ug a radioactive grad 40 contaiaiag small pockets 46 filled with radioactive balls 42. Beside co-. ~truding techniques, the graft 40 can also be created by implanting or enezpsulating tire t '' radioactive balls 42 after graft fabrication.
In a Bdlh aabodiment; much Iike the first and third cmbodituents, radiosdive or radiophatmaceutieat aarc izupregaated directly into the wall of as ePTFE graft without boing aggregated as "sends". in this case, the radioactive agent can come iri the foes of a IO gnouad up solid or powder which is coextruded with the PT~1~. Whit refexence to the first, third and fifth embodiments, Fig. 5 illustrates a ram extruder assembly 50 for co-acrtuding a billet of material, whirls is this case consists of PTFE mixed wilt: any of the radioactive agents described. The ram extzuder assembly 50 includes as extrusion bxael 52,. an extrnsiau die 54, a mandrel 55, and g ram 58. The billet of material S9 is placed within tho .
I S cxtnuion barrel 5Z. Force is applied to i~a s8 which in tern cxpols pressiu~e on Errs YtiIIet of , . ~aI 59. The gr~ causes the bola of tnataial 59 to be extruded around the mandrel . .. _ 56, through t~ttc ion die 54 so that it issue as a tubular a~ctrud~e 60. An arrow 62 shows tbc direction of the ~ctrarion. The tubular adtudate b0 is then eapaaded and s is acdordaace wig , the atpsas:.on and sinteaag Procedures tmdcrtakea with puss PTFE
ZO vascular grafts which errs well known in the art. 'Where plastic aarased radioactive HqQid ball 4,i are used, earapsulation materials arc selected so that the~exttusion process does not Emvfane; ~, ~~ ~ _ ,~..~
AMENDED SHEET
result in rupture of the balls 42 and release of radioactive liquid.
Having thus described a preferred embodiment of the radioactive graft, it will be apparent to those skilled in the art how certain advantages of the present invention have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of~the present invention. Some examples have been illustrated with ePTFE as a biomedical material, but it should be apparent that the inventive concepts described above would be equally applicable to polyester, organosilicon, polyurethane or any other biomedical material that can be extruded or woven. Moreover, the words used in this specification to describe the invention and its various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification.
Thus, if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself. The definitions of the words or elements of the following claims are, therefore, defined in this specification to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same fimction in substantially the same way to obtain substantially the same result. The described embodiments are to be considered illustrative rather than restrictive. The invention is further defined by the following claims.
Claims (10)
1. An impalatable radioactive device for preventing tissue proliferation, comprising a graft structure composed of pliable material, wherein a radioactive element is incorporated therein, characterized in that the graft structure is for use as a replacement or bypass vessel and the radioactive element is selected from the group consisting of radioactive powder, radioactive solid particles (12) and units of encapsulated radioactive liquid (42).
2. The implantable radioactive device according to claim 1, wherein the radioactive element is mixed into and co-extruded with the graft structure.
3. The implantable radioactive device as is claims 1 or 2, wherein the pliable material is selected, from the group consisting of expanded polytetrafluoroethylene, polyester, silicone rubber, polyurethane, and fluoropolymers.
4. An implantable radioactive device suitable as a replacement or bypass vessel for preventing tissue proliferation, comprising a graft (34) composed of pliable material, having a radioactive component associated therewith, characterized in that the radioactive component comprises a coiled flexible wire (32) extending at least partially along the longitudinal axis of the graft.
5. The implantable radioactive device according to claim 4, wherein the flexible wire further comprises beading, having a radioactive element contained therein.
6. The implantable radioactive device as is claims 4 or 5, wherein the flexible wire is adhered to the exterior of the graft.
7. The implantable radioactive device as in claims 4 or 5, wherein the flexible wire is woven into the graft.
8. The implantable radioactive device as in any of claims 4, 6 or 7, wherein the flexible wire is coated with an organic plastic material.
9. The implantable radioactive device as in any of claims 4-8, wherein the graft is composed of a material selected from the group consisting of expanded polytetrafluoroethylene, polyester, silicone rubber, polyurethane, and fluoropolymers.
10. A process for producing an implantable radioactive device suitable as a replacement or bypass vessel for preventing tissue proliferation, comprising the step of selecting a plurality of particles (12, 42) comprising a material that can be rendered radioactive, characterized by combining the particles (12, 42) with a plurality of polytetrafluoroethylene particles and a liquid, forming an extrudate by extruding the mixture, expanding the extrudate; and treating the extrudate to render the particles radioactive.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US40143799A | 1999-09-22 | 1999-09-22 | |
| US09/401,437 | 1999-09-22 | ||
| PCT/US2000/026111 WO2001021106A1 (en) | 1999-09-22 | 2000-09-21 | Radioactive graft or cuff |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2381815A1 true CA2381815A1 (en) | 2001-03-29 |
Family
ID=23587759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002381815A Abandoned CA2381815A1 (en) | 1999-09-22 | 2000-09-21 | Radioactive graft or cuff |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP1214019A1 (en) |
| JP (1) | JP2003509156A (en) |
| CA (1) | CA2381815A1 (en) |
| MX (1) | MXPA02003066A (en) |
| WO (1) | WO2001021106A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6471671B1 (en) | 2000-08-23 | 2002-10-29 | Scimed Life Systems, Inc. | Preloaded gas inflation device for balloon catheter |
| US6416492B1 (en) | 2000-09-28 | 2002-07-09 | Scimed Life Systems, Inc. | Radiation delivery system utilizing intravascular ultrasound |
| US6923927B2 (en) | 2000-10-03 | 2005-08-02 | Atrium Medical Corporation | Method for forming expandable polymers having drugs or agents included therewith |
| US6616876B1 (en) | 2000-10-03 | 2003-09-09 | Atrium Medical Corporation | Method for treating expandable polymer materials |
| AU2002953440A0 (en) | 2002-12-19 | 2003-01-09 | Unisearch Limited | A method of treating a stiffened vessel |
| JP2009514656A (en) * | 2005-11-09 | 2009-04-09 | シー・アール・バード・インコーポレーテッド | Graft and stent graft with radiopaque beading |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5616114A (en) | 1994-12-08 | 1997-04-01 | Neocardia, Llc. | Intravascular radiotherapy employing a liquid-suspended source |
| IT1291001B1 (en) * | 1997-01-09 | 1998-12-14 | Sorin Biomedica Cardio Spa | ANGIOPLASTIC STENT AND ITS PRODUCTION PROCESS |
| US5873811A (en) * | 1997-01-10 | 1999-02-23 | Sci-Med Life Systems | Composition containing a radioactive component for treatment of vessel wall |
| NL1008093C2 (en) * | 1998-01-22 | 1999-07-26 | Hendrik Glastra | Sheet material, method of manufacturing it and sleeve-shaped reinforcing element formed using this material. |
-
2000
- 2000-09-21 CA CA002381815A patent/CA2381815A1/en not_active Abandoned
- 2000-09-21 EP EP00965347A patent/EP1214019A1/en not_active Withdrawn
- 2000-09-21 MX MXPA02003066A patent/MXPA02003066A/en unknown
- 2000-09-21 JP JP2001524536A patent/JP2003509156A/en active Pending
- 2000-09-21 WO PCT/US2000/026111 patent/WO2001021106A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| JP2003509156A (en) | 2003-03-11 |
| EP1214019A1 (en) | 2002-06-19 |
| WO2001021106A1 (en) | 2001-03-29 |
| MXPA02003066A (en) | 2003-09-05 |
| WO2001021106A9 (en) | 2002-10-03 |
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