Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-08-05
2004-03-23
Hayes, Michael J. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S511000
Reexamination Certificate
active
06709427
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to medical systems and procedures and more particularly to systems and procedures for delivering a flowable treatment agent into targeted tissues, e.g., cardiac tissue, of a living being.
Cardiovascular disease is the leading cause of death in the industrial world today. During the disease process, atherosclerotic plaques develop at various locations within the arterial system of those affected. These plaques restrict the flow of blood through the affected vessels. Of particular concern is when these plaques develop within the blood vessels that feed the muscles and other tissues of the heart. In healthy hearts, cardiac blood perfusion results from the two coronary arterial vessels, the left and right coronary arteries that perfuse the myocardium from the epicardial surface inward towards the endocardium. The blood flows through the capillary system into the coronary veins and into the right atrium via the coronary sinus. When atherosclerosis occurs within the arteries of the heart it leads to myocardial infarctions, or heart attacks, and ischemia due to reduced blood flow to the heart tissues. Over the past few years numerous devices and methods have been evaluated for treating cardiovascular disease, and for treating the resulting detrimental effects that the disease has upon the myocardium and the other heart tissues. They are: traditional surgical methods (e.g. open heart surgery), minimally invasive surgery, traditional interventional cardiology (e.g. angioplasty, atherectomy, stents), and advanced interventional cardiology (e.g. catheter based drug delivery). Other recent advances in cardiovascular disease treatment involve transmyocardial revascularization (TMR), and growth factor and gene delivery.
Traditional methods for treating cardiovascular disease utilize open surgical procedures to access the heart and bypass blockages in the coronary blood vessels. These procedures require an incision in the skin extending from the supra-sternal notch to the zyphoid process, the sawing of the sternum longitudinally in half, and the spreading of the rib-cage to surgically expose the patient's heart. Based upon the degree of coronary artery disease, a single, double, triple, or even greater number of vessels are bypassed. Each bypass is typically performed by creating a separate conduit from the aorta to a stenosed coronary artery at a location distal to the occluded site. In general, the conduits are either synthetic or natural bypass grafts. Grafting with the internal thoracic (internal mammary) artery directly to the blocked coronary site has been particularly successful with superior long-term patency results. During conventional cardiac surgery, the heart is stopped using cardioplegia solutions and the patient is put on cardiopulmonary bypass. The bypass procedure uses a heart-lung machine to maintain circulation throughout the body during the surgical procedure. A state of hypothermia may be induced in the heart tissue during the bypass procedure to preserve the tissue from necrosis. Once the procedure is complete, the heart is resuscitated and the patient is removed from bypass.
There are great risks associated with these traditional surgical procedures such as significant pain, extended rehabilitation time and high risk of mortality for the patient. The procedure is time-consuming and costly to perform. Traditional cardiac surgery also requires that the patient have both adequate lung and kidney function in order to tolerate the circulatory bypass associated with the procedure and a number of patients which are medically unstable are thus not a candidate for bypass surgery. As a result, over the past few years, minimally invasive techniques for performing bypass surgery have been developed and in some instances the need for cardiopulmonary bypass and extended recovery times are avoided. A number of companies, e.g., Heartport, Inc. of Redwood City, Calif. and Cardiothoracic Systems, Inc. of Cupertino, Calif., have developed devices that allow for cardiac surgical procedures that do not require a grossly invasive median sternotomy or traditional cardiopulmonary bypass equipment. The procedures result in a significant reduction in pain and rehabilitation time.
In addition, as an alternative to surgical methods, traditional interventional cardiology methods (e.g. angioplasty, atherectomy, and stents) non-surgical procedures, such as percutaneous transluminal coronary angioplasty (PTCA), rotational atherectomy, and stenting have been successfully used to treat this disease in a less invasive non-surgical fashion. In balloon angioplasty a long, thin catheter having a tiny inflatable balloon at its distal end is threaded through the cardiovascular system until the balloon is located at the location of the narrowed blood vessel. The balloon is then inflated to separate and expand the obstructing plaque and expand the arterial wall, thereby restoring or improving the flow of blood to the local and distal tissues. Rotational atherectomy utilizes a similarly long and thin catheter, but with a rotational cutting tip at its distal end for cutting through the occluding material. Stenting utilizes a balloon tipped catheter to expand a small coil-spring-like scaffold at the site of the blockage to hold the blood vessel open.
While many patients are successfully relieved of their symptoms and pain with traditional interventional procedures, in a significant number of patients the blood vessels eventually restenose or reocclude within a relatively short period of time. As such, researchers have explored advanced interventional cardiology methods (e.g., catheter based drug delivery, radiation therapy, etc.) to delay or prohibit the process of restenosis. As summarized by Raoul Bonan, MD. (“Local Drug Delivery for the Treatment of Thrombus and Restenosis, IAGS Proceedings, The Journal of Invasive Cardiology, 8:399-408, October 1996), the cardiology community has recently begun to augment standard catheter-based treatment techniques with devices that provide local delivery of medications to the treated site. This localized administration of drugs has shown promise for counteracting clotting, reducing inflammatory responses, and blocking proliferative responses.
Several devices are reported to be under evaluation for site specific drug delivery, such as the so-called “Channel Balloon” catheter of Boston Scientific (Natick, Mass.), the “Infiltrator” device of InterVentional Technologies (San Diego, Calif.), the “InfusaSleeve” device of LocalMed Inc. (Sunnyvale, Calif.), the “Dispatch” catheter of SciMed/Boston Scientific (Natick, Mass.), and an ultrasound enhanced catheter of EKOS (Bothell Wash.). The “Channel Balloon” catheter is an over-the-wire catheter with separated ports for balloon inflation and drug infusion. The “Infiltrator” device utilizes nipples in a balloon to force a drug into vessel wall.
U.S. Pat. No. 5,279,565 (Klein et al.) discloses a device for infusing a treatment site with a medicinal agent. The device has a flexible body and deflectable support frames that are deployed radially against the intended treatment site. The InfusaSleeve device of LocalMed, Inc. slides over existing balloons to position drug delivery ports against the artery wall. The Dispatch is an over the wire catheter with separate ports for drug infusion and balloon inflation.
U.S. Pat. No. 5,527,292 (Adams et al.) describes an intravascular device having an elongated flexible tube sized for insertion into a coronary vessel beyond a distal end of a guide catheter. In certain applications, the intravascular device is used as a drug (or other fluid) delivery device or as an aspiration device. In other applications, the intravascular device is used as a guiding means for placement of an angioplasty device, such as a guide wire or a balloon catheter. EKOS (Bothell, Wash.) has developed a site-specific catheter that uses ultrasound energy to enhance the performance of a thrombolytic drug. The ultrasound energy transports the drug molecules into
Evans Douglas G.
Hoganson David M.
Nash John E.
Caesar Rivise Bernstein Cohen & Pokotilow Ltd.
Hayes Michael J.
Kensey Nash Corporation
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