1. Field of the Invention
This invention pertains to treating coronary artery disease. More particularly, this invention pertains to treating such disease with a conjunctive therapy of a coronary stent and an anti-restenosis agent applied at an epicardial surface of a patient's heart.
2. Description of the Prior Art
The history of treatment of coronary artery disease includes a progressive development of less-invasive procedures for treating coronary vessel occlusion. Traditional bypass procedures include harvesting a patient's blood vessel and using the harvested vessel to create a new blood flow path which terminates distal to a coronary occlusion. Historically, such surgical procedures required a highly invasive sternotomy. Less invasive surgical procedures such as thoracotomies have been developed.
Non-surgical (i.e., percutaneous) options have been developed for treating occluded blood vessels. Angioplasty involves placement of a balloon in a coronary vessel at an occlusion site. The balloon is inflated to improve the patency of the blood vessel. Further, mechanical supports (i.e., stents) have been developed for placement in the blood vessel at the occlusion site. Such stents may be self-expanding or balloon expanded.
Historically, coronary stents were bare metal stents (e.g., stainless steel, nitinol or other bio-compatible material). More recently, drug-eluting stents have been developed. These stents include an anti-restenosis drug to abate restenosis following placement of the stent. Commonly, the drug is carried in a polymer matrix permitting delayed release of the drug over a period of time following stent placement.
Drug-eluting stents have exhibited a material improvement in abating restenosis. However, with passage of time, such stents have exhibited an apparent increased likelihood of thrombosis relative to bare metal stents. It is believed the thrombogenic experience is related to the polymer matrix which carries the anti-restenosis drug. Namely, after the anti-restenosis drug is discharged from the matrix, the polymer of the matrix remains on the stent and presents a site for thrombus formation.
One of several inventions disclosed in this application includes a conjunctive therapy of a stent and an epicardial delivered anti-restenosis agent.
The pericardium is a sack surrounding the exterior surface (i.e., epicardium or epicardial surface) of the heart. Incisions through the pericardium can result in adhesions which may complicate future heart treatments.
Less invasive procedures have been described for accessing the pericardial space (i.e., the space defined between the pericardium and the epicardial surface). These include surgical and percutaneous procedures. As used herein, “surgical” access means accessing a pericardial space from an exterior side of the pericardium. “Percutaneous” access means accessing the pericardial space without penetrating through the tissue of the pericardium.
Examples of such less invasive surgical procedures are shown in the following (all of which are incorporated herein by reference as though set forth in full): U.S. Pat. No. 5,634,895 to Igo et al. issued Jun. 3, 1997; U.S. patent application Publication No. US 2006/0074373 to Walsh et al. published Apr. 6, 2006; U.S. patent application Publication No. US 2006/0189840 to Walsh et al. published Aug. 24, 2006; U.S. patent application Publication No. US 2005/0261673 to Bonner et al. published Nov. 24, 2005 (also enumerating various therapeutic agents); U.S. Pat. No. 7,186,214 to Ness issued Mar. 6, 2007; U.S. Pat. No. 6,206,004 to Schmidt et al. issued Mar. 27, 2001; U.S. Pat. No. 6,156,009 to Grabek issued Dec. 5, 2004; U.S. Pat. No. 5,972,013 to Schmidt issued Oct. 26, 1999 and U.S. Pat. No. 5,931,810 to Grabek issued Aug. 3, 1999.
Examples of such less invasive percutaneous procedures are shown in the following (all of which are incorporated herein by reference as though set forth in full): U.S. Pat. No. 5,269,326 to Verrier issued Dec. 14, 1993; U.S. Pat. No. 6,200,303 to Verrier et al. issued Mar. 13, 2001; U.S. patent application Publication No. US 2001/0039410 to Verrier et al. published Nov. 8, 2001; U.S. Pat. No. 5,968,010 to Waxman et al. issued Oct. 19, 1999; U.S. Pat. No. 6,582,536 to Shimada issued Jun. 24, 2003; U.S. Pat. No. 7,207,988 to Leckrone et al. issued Apr. 24, 2007; U.S. Pat. No. 6,692,458 to Forman et al. issued Feb. 17, 2004; U.S. Pat. No. 4,884,567 to Elliott et al. issued Dec. 5, 1989; U.S. Pat. No. 6,613,062 to Leckrone et al. issued Sep. 2, 2003; U.S. patent application Publication No. US 2006/0247672 to Vidlund et al. published Nov. 2, 2006; U.S. patent application Publication No. US 2007/0010793 to Callas et al. published Jan. 11, 2007; U.S. patent application Publication No. US 2006/0173441 to Gelfand et al. published Aug. 3, 2006; U.S. patent application Publication No. US 2006/0074397 to Shimada published Apr. 6, 2006; and U.S. Pat. No. 5,087,243 to Avitall issued Feb. 11, 1992 (describing myocardial iontophoresis).
One of several inventions disclosed in this application includes a novel method and apparatus for delivery of a therapeutic agent to the pericardial space.
The description of the present invention includes placement of a cardiac therapeutic agent at an epicardial surface. Such agents are well-known in the art and form no part of this invention per se. Examples of such are described in the following (all of which are incorporated herein by reference as though set forth in full): U.S. patent application Publication No. US 2003/0060415 to Hung published Mar. 27, 2003 (enumerating a variety of such agents including anti-restenosis agents and agents administered to the epicardial space); U.S. patent application Publication No. US 2005/0261673 to Bonner et al. published Nov. 24, 2005; U.S. Pat. No. 5,634,895 to Igo et al. issued Jun. 3, 1997 (including describing delivery of anti-restenosis agents to the pericardial space); U.S. patent application Publication No. US 2003/0032998 to Altman published Feb. 13, 2003 (including describing a rolled epicardial patch for distributing a drug to an epicardial surface—e.g., paragraph 0084 of the '998 application); U.S. Pat. No. 6,977,080 to Donovan issued Dec. 20, 2005; International Publication No. WO 2006/076342 A2 published Jul. 20, 2006; U.S. patent application Publication No. US 2003/0109442 to Bisgaier et al. published Jun. 12, 2003 (describing restenosis treatment with localized delivery of therapeutic agent); U.S. patent application Publication No. US 2004/0102759 to Altman et al. published May 27, 2004 (including treating of coronary artery disease with therapeutic agents injected into heart wall tissue); U.S. patent application Publication No. US 2006/0084943 to Rosenman et al. published Apr. 20, 2006 (including therapeutic agent delivery carriers implanted into heart wall tissue); U.S. patent application Publication No. US 2006/0292125 to Kellar et al. published Dec. 28, 2006; U.S. patent application Publication No. US 2007/0078620 to Seward et al. published Apr. 5, 2007 (including method and kits for delivering pharmaceutical agents to adventia surrounding a blood vessel); U.S. patent application Publication No. US 2003/0004141 to Brown published Jan. 2, 2003 (including describing polymeric compounds impregnated with a therapeutic agent for delayed delivery); U.S. patent application Publication No. 2003/0009145 to Struijker-Boudier et al. published Jan. 9, 2003 (including describing delivery of drugs from sustained release devices implanted in myocardial tissue or in the pericardial space); U.S. Pat. No. 6,333,347 to Hunter et al. issued Dec. 25, 2001 (describing intrapericardial delivery of agents for treating a variety of cardiac diseases); U.S. Pat. No. 5,482,925 to Keefer et al. issued Jul. 22, 1997 (describing nitric oxide releasing polymers to treat restenosis); U.S. Pat. No. 7,208,011 to Shanley et al. issued Apr. 24, 2007 (describing an implantable medical device with drug filled holes) and U.S. Pat. No. 5,387,419 to Levy et al. issued Feb. 7, 1995 (controlled release, site specific myocardial agents in polymeric matrix at epicardium).
According to a preferred embodiment of the present invention, a method and kit are disclosed for a conjunctive method of treating coronary artery disease for use in conjunction with a primary treatment. In the primary treatment, a stent is placed in a coronary artery of a patient at a site of an occlusion. The conjunctive method comprises placing a therapeutic agent at an epicardial surface of a heart of the patient and at the site of the occlusion. The therapeutic agent is selected for abating restenosis at the site.
Referring now to the several drawing figures in which identical elements are numbered identically throughout, a description of a preferred embodiment of the present invention will now be provided. The present invention is described in a currently preferred embodiment as an adjunctive treatment with prior art coronary artery stents. However, the invention is not intended to be so limited and may include a stand-alone therapy for a wide variety of uses including treatments for ischemia, infarction, vulnerable plaque and other cardiac disorders.
By way of background,
With the prior art procedures of
While drug-eluting stents have been very effective in reducing restenosis, long-term (for example, two to four years following stent placement) drug-eluting stents are shown in certain studies to have higher incidences of thrombus formation over bare metal stents. While bare metal stents (i.e. not drug-eluting stents or drug-coated stents) are more likely to experience restenosis during a short-term period (e.g., less than 6 to 12 months), such stents which do not restenose are more likely to have successful endothelial growth relative to drug-eluting stents and less potential for late term thrombosis (e.g., after one year). With such endothelial growth, blood flow to the coronary artery is not exposed directly to the metal of the stent thereby reducing the likelihood of platelet activation or other responses to foreign bodies within the blood flow. It is believed that such thrombus formation is due to the fact that the sites on the stent which release the drug present blood-contact surface which can produce thrombus formation.
In its most preferred embodiment, the present invention is an adjunct procedure for use with placement of a bare metal stent at an occlusion site within a coronary artery. The invention is illustrated in
The implant 10 is shown in
It will be appreciated that
The implant 10 is a carrier for a therapeutic agent to treat coronary disease residing beneath the position of the implant 10. In the embodiments of
The implant 10 is delivered to the epicardial surface E through the pericardial space PS. Access to the pericardial space PS may be either surgical or percutaneous through any of the techniques disclosed in the previous section of this application titled “Pericardial Access Procedures”. In percutaneous access, implant 10 is preferably delivered through an atrial appendage into the pericardial space PS.
In either of the pericardial access procedures, a small diameter catheter 12 (
In
The material of the implant 10 is biocompatible for chronic placement in the pericardial space PS. It may be an elastic material or material which assumes the second geometry by reason of phase change of the material. It will be appreciated that such materials (both plastic and metal) are well known in the art (such as nitinol and polymer materials). The therapeutic agent may be in a polymer coating on the material of the implant. The agent is selected that upon release it penetrates heart tissue to a coronary artery (e.g., capable of tissue penetration up to 5 mm). Such drugs are none in the art are in included in those described in the section “Therapeutic Agents”.
The implant 10 may contain radiopaque markers to permit visualization by a physician when placing the implant 10 within the pericardial space PS to ensure positioning over the stent S. The implant 10 may be placed during the same procedure at the placement of the stent S or may be placed before or after placement of the stent S. Drugs from the implant 10 are released over time and migrate through the myocardium M to the coronary artery at the site of the stent S to provide the desired therapy of anti-restenosis drugs at the stent site. Implant 10 may include sufficient drugs for full release (e.g., 90% of the original amount of the drug) of the drugs over a time period (for example, 30 to 45 days) to abate restenosis at the site of the stent S.
The previously described embodiment of the present invention is an implant 10 in the form of a implant sized to have a surface area overlying the epicardial surface E to cover the area of a stent S placed within a coronary artery CA beneath the epicardial surface E.
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The implant 10e of
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In all of the disclosed embodiments, the implant discharges a therapeutic agent over time. The therapeutic agent migrates through the myocardial tissue to a desired treatment site of the heart. The implant is positioned within the heart at the epicardial surface by delivery from a delivery tool admitted into the pericardial space. Following delivery, the delivery tool is removed leaving the implant 10 completely contained within the heart (i.e., not exposed through the pericardium).
With the present invention now disclosed in the preferred embodiment, modifications and equivalents of the disclosed concepts may occur to one of ordinary skill in the art. It is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.
This application claims subject matter disclosed in commonly assigned and co-pending U.S. patent application Ser. No. [not yet assigned] filed on even date herewith and in the name of the same inventors as the present application and titled “Cardiac Tissue Therapy”.