Coated endovascular devices

Abstract

The present disclosure relates to the field of medical treatment. More particularly, the current invention delivers medication via a coating via a hydrogel infused with pharmaceutical compounds into the bloodstream to promote the supply to the distal vascular bed beyond the stent. The present invention uses in a preferred embodiment a stent with a thin coating of biodegradable or non-biodegradable hydrogel designed to ameliorate or eliminate vasospasms or thromboses, or to treat cancer, which hydrogel may optionally be impregnated with pharmaceutical compounds. The present invention also teaches the use of thin hydrogel coatings to ameliorate treatment related difficulties.

Claims

1. A device for ameliorating thrombosis and tissue reactions by deploying a thin coating of hydrogel.

2. The device of claim 1, wherein said hydrogel is deployed upon the outer surface of a stent.

3. The device of claim 1, wherein said hydrogel is deployed upon the inner surface of a stent.

4. The device of claim 1, wherein said hydrogel is deployed upon the interstices in the surface of a stent.

5. The device of claim 1, wherein said hydrogel is impregnated with at least one pharmaceutical compound.

6. The device according to claim 5, for wherein said at least one pharmaceutical compound is released into the blood at a prescribed dose over a prescribed time.

7. The device of claim 1, wherein said device said hydrogel is coated upon any surface exposed to blood or a lumen wall.

8. The device according to claim 1, wherein said hydrogel is coated upon all surfaces of a stent.

9. The device according to claim 1, wherein said hydrogel is deployed upon a stent and expands to occlude the intersteces of said stent.

10. The device according to claim 1, wherein said hydrogel is deployed upon a stent but does not expand sufficiently to occlude the intersteces of said stent.

11. The device of claim 1, wherein said hydrogel is biodegradable.

12. The device of claim 1, wherein said hydrogel is non-biodegradable.

13. The device according to claim 1, wherein said hydrogel is deployed upon a cardiac prosthesis.

14. The device according to claim 1, wherein said hydrogel is deployed upon an orthopedic device.

15. A device comprising a stent for deployment in a body lumen, a coating adhered to said stent, wherein said coating is capable of containing at least one pharmaceutical compound, releasing said at least one pharmaceutical compound into said body lumen for downstream therapy.

16. The device of claim 15, wherein said coating is a hydrogel.

17. The device of claim 15, wherein the device is adapted for intravascular use.

18. The device of claim 15, wherein said device is adapted for use in the genitourinary tract.

19. The device of claim 15, wherein said device is adapted for use in the biliary tract.

20. The device of claim 15, wherein said device is adapted for use in a gastrointestinal tract.

21. The method of treating vasospasm via implanting at least one stent that releases at least one vasodilator pharmaceutical into a vascular territory.

22. The method of prophylactively ameliorating post-aneurysmal vasospasm via implanting at least one stent that releases at least one vasodilator pharmaceutical into a vascular territory.

23. The method of delivering at least one chemotherapy via implanted stents impregnated with at least one chemotherapy agent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detail description thereof. Such description makes reference to the annexed drawings wherein:

[0043] FIG. 1 is a planar view showing a stent covered in hydrogel depicted as misformed circles or beads.

[0044] FIG. 2 depicts a cross-section of the embodiment of the present invention shown in FIG. 1, situated within in a mammalian vessel, without showing the delivery system.

[0045] Note that hydrogel coating is depicted in the foregoing Figures as misformed circles or beads as being representative only, and said circles or beads shown are not drawn to scale

DETAILED DESCRIPTION OF THE INVENTION

[0046] The present disclosure teaches the placement of hydrogel within or coating surfaces of intravascular devices and stents, which are often delivered proximally to target area using a stent allowing for the implementation of a therapeutic endovascular treatment.

[0047] Referring now to FIG. 1, a stent 10 disposed upon a delivery device 20. Stent 10 is shown deployed within vessel wall 100.

[0048] Stent 10 includes a distal end 11. Delivery device 20 has a distal end 21.

[0049] Stent 10 is coated with hydrogel 15 or 16. Hydrogel 15 or 16 is typically amorphous. It is adhered to all or select surfaces of stent 10 or other intravascular device.

[0050] In a preferred embodiment, stent 10 is covered with a one (1) nanometer to one (1) millimeter layer of hydrogel 15 or 16 to prevent thrombosis and tissue reactions. Another embodiment includes impregnating medications into hydrogel 15 or 16 on stent 10. This alternate embodiment may have multiple subgroups including chemotherapy and vasodilator agents, among others. This embodiment could also have multiple applications for treatment of cancer, vasospasm, and other diseases, with varying the medications and the location of the stent.

[0051] Referring now to FIG. 2, a cross-section of deployed covered stent 10 within vessel wall 100, showing hydrogel 15 or 16 coating on the outer surface 15 and the inner surface 16.

[0052] When said coated device 10 is employed in an endovascular treatment, the exposure of the adhered added hydrogel 15 or 16 with the device 10 to the blood and temperature in the body causes it to expand further, decreasing the permeability of device 10 to blood and which decreases the risk of the aneurysm rupturing or clots forming and embolizing.

[0053] The present invention uses a device designed to facilitate endovascular treatment by coating hydrogel along delivery device 20 to prevent episodes of distal migration due to addition of hydrogel 15 and 16.

[0054] In the preferred embodiment of the current invention a thin coating of hydrogel 15 and 16 is placed on all surfaces, including the surface pressing on the vessel wall to reduce the rate of intimal hyperplasia caused by the vessel reacting to the foreign body. This results in a non-obvious benefit of the use of hydrogel 15 and 16 because vasospasms turn cause sub-optimal outcomes, including in some cases the death of the patent.

[0055] The thickness of the hydrogel 15 and 16 coating on the stent 10 would be from the minimum possible thickness of approximately one nanometer or less, up to one centimeter in thickness. However, for most carotid and vertebral artery applications the preferred thickness is one millimeter or less.

[0056] In general dosage depends on the specific medication and the intended task. For example, Verapamil 2 mg/hr and Cardene 100 mcg/hr are non-limiting examples of medication doses that are released to the blood for cases of vasospasm. Various possible vasodilators, including and not limited to the ones listed herein may be infused for treating vasospasms; any chemotherapy agent may be employed for treatment of cancer.

[0057] In alternate embodiments (not shown), hydrogel 15 and 16 is lined onto nonvascular stents 10, such as biliary and ureter stents, to reduce rates of in-stent stenosis; and may help anchor the stent 10 in place and prevent stent migration.

[0058] In another alternate embodiment (not shown), hydrogel 15 and 16 does not fill the interstices between metal areas of stent 10.

[0059] In alternate embodiments, hydrogel may be coated on such devices as a delivery mechanism of medications, which can be immediate release or controlled sustained slow release.

[0060] Slow, local release of adhered medications is also useful in treating certain cancers.

[0061] In some embodiments, a bio-degradeable hydrogel is employed.

[0062] In another embodiment, a non-biodegradable hydrbiogel, that will be permanent, may be employed.

[0063] In some embodiments said additional coating includes chemotherapy compounds in said thin coating of hydrogel. As examples, said chemotherapy compounds embedded a device may be used in the carotid artery for a brain tumor in that vascular distribution, or in right renal artery for a right kidney tumor, or in right pulmonary artery for a right lung mass. This could allow sustained delivery locally, while minimizing the systemic dose and associated side effects.

[0064] Said hydrogel thin coating may be impregnated with pharmaceutical compounds to ameliorate vasospasm. Said compounds may include, but are not limited to nimodipine, Verapamil, Cardene, nitroglycerin, and nitroprusside. Said compounds may be formulated for immediate release or controlled sustained slow release.

[0065] By way of non-limiting example, impregnating hydrogel adhered to a stent with Verapamil that is released over two weeks, and placing said stent in carotid artery, may be used to treat intracranial vasospasm. In addition or in the alternative, impregnating hydrogel adhered to a stent with a slow release chemotherapy agent, allowing selective delivery over a time to a single organ, with lower systemic doses, is likely to lead to fewer side-effects. It may allow higher and more effective local doses of medication as well.

[0066] To minimize the risk of severe symptomatic vasospasm in aneurysmal subarchnoid hemorrhage (a typical bleed from a ruptured brain aneurysm) or other intracranial vasoconstriction syndrome, the said thin coating of hydrogel might include a vasodilator compound that slowly releases over two to four weeks. Said medication infused hydrogel can be embedded in a stent for placement in the common or internal carotid arteries on one or both sides, and/or the placement in one or both vertebral arteries. Non-limiting examples of vasodilators that can be embedded include nimodipine, Verapamil, Cardene, nitroglycerin, and nitroprusside. They can be implanted therapeutically after vasospasm is identified. In some cases they can be implanted prophylactically, before the onset of vasospasm.

[0067] The objective of the present invention is to deliver pharmaceutical compound(s) downstream from the stent 10. The present invention teaches four techniques to achieve this objective in a manner which is superior to the prior art.

[0068] First, the hydrogel 15 and 16 which contains the pharmaceutical compounds is located both inside and outside the stent 10 wall. Said positioning allows blood flowing through stent 10 to leach medication from hydrogel 15 or 16. Said blood flow then delivers said pharmaceutical compounds downstream of stent 10. Hydrogel 16 (interior surface) differs from the prior art because the prior art deposits the pharmaceutical compound directly on the outer surface of a (typically) metal stent.

[0069] When the prior art devices release the pharmaceutical compounds, they expose metal surfaces either inside the prior-art stent, thus harming the blood, or outside the metal stent, thus harming the vessel tissue in contact with the vessel wall 100. In light of the fact that it is known that exposure of blood to metal causes injury, the present invention in its preferred embodiment uses an intermediate compound such as hydrogel 15 or 16, which covers the stent 10 both inside and out, after the medication has been leached away, thus preventing injury of the metal contact with either the blood or the vessel wall 100. Coating hydrogel 16 inside stent 10 allows superior downstream results as compared to prior-art devices.

[0070] The second technique to enhance superior downstream results, when compared to the prior art, is the present invention's asymmetrical distribution of the hydrogel 15 and 16, in some embodiments. By placing relatively more hydrogel 15 and 16 toward the downstream end of stent 10, pharmaceutical compounds are more likely to exit stent 10 and travel further from stent 10 then if the compounds were uniformly distributed on a stent 10, as disclosed by the prior art.

[0071] The third technique, in some embodiments, is to shape the inside of stent 10 to produce spiral flow. Said shaping may be achieved by either forming internal spiral ridges on the inside of stent 10, or plating the inside of stent 10 with spiral mounds of hydrogel 15 and 16. Either the spiral ridges coated with hydrogel or spiral mounds of hydrogel will result in changing the course of the blood flow through stent 10. More particularly, such spiral-coated structures or mounds will cause the blood flow through stent 10 to spiral. Such spiraling will encourage turbulent flow. Turbulent flow has a well-known characteristic of clumping particulate matter such as pharmaceutical compounds in the center of the flow. Particulate matter in the center of the flow will go further downstream than particulate matter under laminar-flow conditions.

[0072] The fourth technique, in some embodiments, is to make the downstream stent 10 opening smaller than the upstream stent 10 opening. It is well known that constricting a fluid results in turbulent flow. Therefore, for the reasons noted above, pharmaceutical compounds will travel in the center of the flow further downstream than stents with similarly sized openings, as disclosed by the prior art.

[0073] The foregoing four techniques, individually or in a combination of one or more of these techniques, may also be used to control the amount and distance the pharmaceutical compounds will be sent downstream in addition to allowing superior downstream range of pharmaceutical-compound delivery as compared to the prior art.

[0074] The present invention can alternatively be used by embedding or impregnating pharmaceutical compounds medications in stent 10 for local delivery, short release or sustained release, using permanent non-degradeable hydrogel or biodegradable hydrogel. The following are non-limiting embodiments.

[0075] Placing a stent with chemotherapy embedded into carotid artery for a brain tumor in that vascular distribution, or in right renal artery for a right kidney tumor, or in right pulmonary artery for a right lung mass. This could allow sustained delivery locally, while minimizing the systemic dose and associated side effects.

[0076] Similarly, to minimize the risk of severe symptomatic vasospasm in aneurysmal subarchnoid hemorrhage (a typical bleed from a ruptured brain aneurysm), a vasodilator that slowly releases over time can be embedded in stent 10 for placement in the common or internal carotid arteries on both sides, with optional additional placement in one or both vertebral arteries. Non-limiting examples of vasodilators that can be embedded include nimodipine, Verapamil, Cardene, nitroglycerin, and nitroprusside.

[0077] Although the invention has been described in detail in the foregoing embodiments and methods for the purpose of illustration, it is to be understood that such detail is solely for that purpose, and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention, except as it may be described by the following claims.