Surgery – Instruments – Cutting – puncturing or piercing
Reexamination Certificate
1999-08-05
2001-03-20
Truong, Kevin (Department: 3731)
Surgery
Instruments
Cutting, puncturing or piercing
C606S220000
Reexamination Certificate
active
06203556
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to medical systems and procedures and more particularly to systems and procedures for effecting revascularization of the myocardium of a living being.
Atherosclerosis is the leading causes 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 of the heart. In healthy hearts, cardiac blood perfusion results from the two coronary arterial vessels, the left and right coronary arteries which 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 muscle.
Over the past few years numerous methods for treating cardiovascular disease have become available. Traditional methods utilize open surgical procedures to access the heart and bypass blockages in the coronary blood vessels. In these procedures, the patient's heart is surgically exposed and one or more coronary arteries are replaced/bypassed with synthetic or natural bypass grafts. During conventional cardiac surgery, the heart is stopped using cardioplegia solutions and the patient is put on cardiopulmonary bypass which uses a heart-lung machine to maintain circulation throughout the body during the surgical procedure. A state of hypothermia is 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 surgical procedures such as significant pain, extended rehabilitation times, and high risk of mortality for the patient. The procedure is time-consuming and costly to perform. This 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. In addition, as an alternative to surgical methods, non-surgical procedures, such as percutaneous transluminal coronary angioplasty, 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 containing 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 compress the obstructing plaque against 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, in a significant number of patients, the blood vessels eventually reocclude within a relatively short period of time. In addition, for a large number of patients that are in the later stages of ischemic heart disease, the current technology offers little hope for long term cure. In these patients even extending the patient's life for several months provides a significant benefit to the patients and their families.
Although these non-surgical procedures are much less costly and less traumatic to the patient than coronary bypass surgery there are a number of patients for which these procedures are not suitable. For certain types of patients the presence of extremely diffuse stenotic lesions and total occlusion in tortuous vessels prohibits them from being candidates. In addition to these procedures which attempt to reopen or bypass the coronary vessels, direct myocardial revascularization has been performed by inducing the creation of new channels, other than the coronary arteries themselves, to supply oxygenated blood and remove waste products from the heart tissue. Myocardial revascularization is a technique used to supplement the blood supply delivered to the heart by providing the ischemic inner surface of the heart, known as the endocardium, with direct access to the blood within the ventricular chamber. Typically the endocardium receives its nutrient blood supply entirely from the coronary arteries that branch through the heart wall from the outer surface known as the epicardium.
In an article entitled “New Concepts In Revascularization Of Myocardium” by Mirhoseini et al. in Ann. Thor. Surg., 45:415-420, April, 1988 the work of investigators exploring several different approaches for direct revascularization of ischemic myocardium is discussed. One revascularization technique utilizes “myoepexy”, which consists of roughening of the myocardial surface to enhance capillarization. Another technique, known as “omentopexy”, consists of sewing the omentum over the heart to provide a new blood supply. Another approach involves implanting the left internal mammary artery directly into heart muscle so that blood flowing through the side branches of the artery will perfuse the muscle.
Similar revascularization techniques have involved the use of polyethylene tubes, endocardial incisions, and the creation of perforated or bored channels with various types of needles, and needle acupuncture. For example, T-shaped tubes have been implanted in the muscle, with the leg of the T-tube extending into the ventricular cavity as reported by Massimo et al. in an article entitled “Myocardial Revascularization By A New Method Of Carrying Blood Directly From The Left Ventricular Cavity Into The Coronary Circulation” appearing in J. Thorac. Surg., 34:257-264, August, 1957. In an article entitled “Experimental Method For Producing A Collageral Circulation To The Heart Directly From The Left Ventricle” by Goldman et al. in the Journal of Thoracic and Cardiovascular Surgery, 31:364-374, March, 1965, several experimental methods for myocardial revascularization are described. One method involved the implantation of excised perforated carotid arteries into the left ventricular wall. Goldman et al. also examined the use of implanted perforated polyethylene tubing in a similar fashion.
Needle acupuncture approaches to direct myocardial revascularization have been made and were based upon the premise that the heart of reptiles achieve myocardial perfusion via small channels between the left ventricle and the coronary arterial tree as described by Sen et al. in their article entitled “Transmyocardial Acupuncture: A New Approach To Myocardial Revascularization” in the Journal of Thoracic and Cardiovascular Surgery, 50:181-187, August, 1965. In that article it was reported that researchers attempted to duplicate the reptilian anatomy to provide for better perfusion in human myocardium by perforating portions of the ventricular myocardium with 1.2 mm diameter needles in 20 locations per square centimeter. It has been shown that the perfusion channels formed by mechanical methods such as acupuncture generally close within two or three months due to fibrosis and scaring. As a result these types of mechanical approaches have been abandoned in favor of the use of lasers to effect the transmyocardial revascularization (TMR).
U.S. Pat. No. 5,591,159 (Taheri) describes a device for e
Evans Douglas G.
Nash John E.
Caesar Rivise Bernstein Cohen & Pokotilow Ltd.
Kensey Nash Corporation
Truong Kevin
LandOfFree
Transmyocardial revascularization system and method of use does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transmyocardial revascularization system and method of use, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transmyocardial revascularization system and method of use will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2475243