Surgery – Miscellaneous – Methods
Reexamination Certificate
2000-08-16
2003-12-02
Isabella, David J. (Department: 3738)
Surgery
Miscellaneous
Methods
Reexamination Certificate
active
06655386
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to medical methods, devices, and systems, and more particularly to methods, devices, and systems for a) revascularization and/or b) performing medical procedures at vascular or non-vascular intracorporeal locations within a mammalian body.
BACKGROUND OF THE INVENTION
A. Background Relating to Revascularization Procedures
In modern medical practice, it is often desirable to bypass segments of artery which have become obstructed, diseased or injured. The typical surgical procedures used for bypassing of obstructed, diseased or injured segments of blood vessel require open surgical exposure of the artery, and the attachment (e.g., suturing) of a tubular graft (e.g., homograft, xenograft, allograft, prosthetic or bioprosthetic graft) to the affected artery such that one end of the graft is connected upstream of the obstructed, diseased or injured segment, and the other end of the graft is connected to the artery downstream thereof. In this manner, arterial blood is channeled through the bypass graft, thereby restoring blood flow distal to the obstructed, diseased or injured segment of artery, and preventing tissue ischemia, infarction, and other sequelae which may result from impaired blood flow through the affected artery.
Although surgical bypass grafting of arteries has been performed at various locations within the body, it is most typical for such arterial bypass procedures to be performed for the treatment of either i) coronary artery disease or ii) peripheral vascular disease affecting the lower extremities.
i. Coronary Artery Disease
Coronary artery disease continues to be one of the leading causes of morbidity and mortality, throughout the world. The typical etiology of coronary artery disease is characterized by the build-up of atherosclerotic plaque within the coronary arteries. Such deposits of atherosclerotic plaque tend to fully or partially block the flow of blood through the affected coronary arteries, and if untreated can result in myocardial ischemia, infarction and death.
For many years, the traditional surgical treatment of coronary artery disease has been coronary artery bypass surgery wherein the patient is generally anesthetized, placed on cardiopulmonary bypass and the patient's heart is temporarily stopped. A thoracotomy (e.g., a median sternotomy) is performed and the obstructed coronary blood vessels are exposed by surgical dissection. One or more segments of the patient's saphenous vein or internal mammary artery is/are harvested for use as bypass graft(s). The harvested segment(s) of vein or artery is/are then anastomosed to the obstructed coronary artery(ies) to form bypass conduit(s) around the arterial obstruction(s). Such traditional coronary artery bypass surgery is expensive, extremely invasive, and is associated with significant operative and postoperative complications.
One alternative to traditional coronary artery bypass surgery is balloon angioplasty. In balloon angioplasty, a flexible guide catheter is percutaneously inserted into a peripheral artery (e.g., the femoral artery) and is transluminally advanced through the vasculature until the distal tip of the catheter is within the ostium of an obstructed coronary artery. Thereafter, a balloon catheter is passed through the guide catheter and into the obstructive lesion. The balloon of the balloon catheter is inflated one or more times to dilate the coronary artery in the region of the obstructive lesion. These balloon angioplasty procedures tend to be less expensive and less traumatic than traditional coronary artery bypass surgery. However, balloon angioplasty procedures of this type may be associated with a significant incidence of restenosis at the angioplasty site. The cause and mechanism of such restenosis continues to be the subject of ongoing study. However, such restenosis has generally been attributed to either a) an increase in the mass of the artery wall (e.g., neointima formation), b) a thickening of the artery wall without substantial change in it's mass (e.g., vascular remodeling) and/or c) radial contraction of the balloon-dilated artery wall upon healing of cracks and fissures that have been created by the balloon dilation process.
Another alternative to traditional coronary artery bypass surgery is intraluminal removal (e.g., atherectomy) or ablation (e.g., ultrasound, laser) of the obstructive matter within the coronary artery. These intraluminal removal or ablation procedures are performed by passing a catheter-mounted removal or ablation apparatus through the vasculature to the site of the coronary obstruction. The catheter-mounted removal or ablation apparatus is then utilized to cut, shave, sonicate, pulverize, or vaporize or otherwise ablate the obstructive matter from the lumen of the coronary artery. These procedures must be performed with caution to avoid perforation or damage to the artery wall, as such perforation or damage can result in hemorrhage or excessive scaring and subsequent reocclusion of the artery lumen. Furthermore, these ablative procedures may, in some cases at least, be confounded by the need to meticulously contain and remove dislodged or severed fragments of the obstructive matter, in order to prevent such fragments of obstructive matter from escaping into the patient's circulatory system. Examples of atherectomy catheters and other catheter-mounted ablative apparatus are described in U.S. Pat. Nos. 3,433,226 (Boyd), 3,823,717 (Pohlman, et al.), 4,808,153 (Parisi), 4,936,281 (Stasz), 3,565,062 (Kuris), 4,924,863 (Sterzer), 4B70,953 (Don Michael, et al.), 5,069,664 (Suess, et al.), 4,920,954 (Alliger, et al.) and 5,100,423 (Fearnot), as well as foreign patents/patent publications EP0347098A2-(Shiber), WO87-05739 (Cooper), WO89-06515 (Bernstein, et al.), WO90-0130 (Sonic Needle Corp.), EP316789 (Don Michael, et al.), DE 3,821,836 (Schubert), DE2438648 (Pohlman), and EP 0443256A1 (Baruch).
Other alternatives to traditional coronary artery bypass surgery have included minimally invasive endoscopic procedures which may, ostensibly at least, be performed through small (e.g., 1-3 cm) incisions formed in the patient's chest wall, by insertion of a thoracoscope and associated operative instruments through such incisions. One such minimally invasive coronary bypass procedure is described in U.S. Pat. No. 5,452,733 (Sterman et al.). If perfected, these minimally invasive coronary artery bypass procedures may lessen the discomfort and length of recovery time experienced by patients who undergo such minimally invasive procedures vis a vis those who undergo traditional coronary artery bypass surgery. However, endoscopic surgical procedures of this type typically require a great deal of operator skill and training. Furthermore, as with traditional coronary artery bypass surgery, these thoracoscopic procedures are typically performed under general anesthesia, and typically require that one or more chest tubes be left in place during the postoperative period to drain any blood which leaks from the graft anastomoses and to reduce the pneumothorax which has been created by the formation of full-thickness incision(s) in the chest wall. Moreover, some of these thoracoscopic coronary artery bypass procedures require that the patient be placed on cardiopulmonary bypass, and that the patient's heart be temporarily stopped. Others of these thoracoscopic procedures purport to be useable without placing the patient on cardiopulmonary bypass, and without stopping the heart. However, those thoracoscopic procedures which are purported to be useable without cardiopulmonary bypass and heart stoppage are relatively complex to perform and typically require temporary clamping or ligating of the coronary artery which is to be bypassed. Accordingly, even those thoracoscopic procedures which may be useable without cardiopulmonary bypass/heart stoppage are prone to unique and significant risks and difficulties due to the complexities of the procedure and the need for temporary clamping or c
Banks Thomas
Evard Philip Christopher
Flaherty J. Christopher
Garibotto John Thomas
Macaulay Patrick Edward
Buyan Robert D.
Isabella David J.
Stout, Uxa Buyan & Mullins, LLP
TransVascular, Inc.
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